WO2016121291A1 - Gear pump and method for manufacturing same - Google Patents

Gear pump and method for manufacturing same Download PDF

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Publication number
WO2016121291A1
WO2016121291A1 PCT/JP2015/086533 JP2015086533W WO2016121291A1 WO 2016121291 A1 WO2016121291 A1 WO 2016121291A1 JP 2015086533 W JP2015086533 W JP 2015086533W WO 2016121291 A1 WO2016121291 A1 WO 2016121291A1
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WO
WIPO (PCT)
Prior art keywords
tooth
teeth
inner rotor
gear pump
clearance
Prior art date
Application number
PCT/JP2015/086533
Other languages
French (fr)
Japanese (ja)
Inventor
雅幸 木村
雅士 服部
光博 武田
Original Assignee
アイシン機工株式会社
アイシン・エィ・ダブリュ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by アイシン機工株式会社, アイシン・エィ・ダブリュ株式会社 filed Critical アイシン機工株式会社
Priority to JP2016571829A priority Critical patent/JP6343355B2/en
Priority to CN201580074754.4A priority patent/CN107208627B/en
Priority to US15/543,624 priority patent/US20170370359A1/en
Priority to DE112015006082.0T priority patent/DE112015006082T5/en
Publication of WO2016121291A1 publication Critical patent/WO2016121291A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/10—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
    • F04C2/102—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member the two members rotating simultaneously around their respective axes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/0057—Driving elements, brakes, couplings, transmission specially adapted for machines or pumps
    • F04C15/0061—Means for transmitting movement from the prime mover to driven parts of the pump, e.g. clutches, couplings, transmissions
    • F04C15/0065—Means for transmitting movement from the prime mover to driven parts of the pump, e.g. clutches, couplings, transmissions for eccentric movement
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C15/00—Component parts, details or accessories of machines, pumps or pumping installations, not provided for in groups F04C2/00 - F04C14/00
    • F04C15/06—Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082—Details specially related to intermeshing engagement type machines or pumps
    • F04C2/084—Toothed wheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2230/00—Manufacture
    • F04C2230/20—Manufacture essentially without removing material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2250/00—Geometry
    • F04C2250/20—Geometry of the rotor

Definitions

  • the present disclosure relates to a gear pump including an inner rotor having a plurality of external teeth and an outer rotor having a plurality of internal teeth and arranged to be eccentric with respect to the inner rotor, and a method for manufacturing the same.
  • a gear pump As a gear pump, one of the pump chambers defined by the external teeth of the external gear and the internal teeth of the internal gear communicates with a pump chamber (interdental chamber) whose volume is increased by the rotation of both gears.
  • a pump chamber internal chamber
  • One having a suction port and two discharge ports communicating with a pump chamber whose volume is reduced by the rotation of both gears is known (for example, see Patent Document 1).
  • This gear pump has a minimum clearance of 0.020 mm or more between the external teeth and the internal teeth located on the partition wall that divides the two discharge ports in a state where the external gear and the internal gear are pressed in opposite directions in the radial direction. And it is designed to be 0.110 mm or less.
  • the pump chamber communicating with one discharge port on the high pressure side and the other on the low pressure side It would be possible to improve the volumetric efficiency of the pump by reducing the leakage of hydraulic oil to the pump chamber communicating with the discharge port.
  • the minimum clearance between the external teeth and the internal teeth located on the partition wall is reduced, cavitation occurs when fluid flows into the pump chamber communicating with the suction port, thereby reducing volumetric efficiency. There is a risk of noise or vibration.
  • the main object of the present disclosure is to provide a gear pump that can suppress the occurrence of cavitation while improving volumetric efficiency, and a method for manufacturing the same.
  • a gear pump of the present disclosure includes an inner rotor having a plurality of external teeth, an outer rotor having a plurality of internal teeth larger than the external teeth of the inner rotor and arranged to be eccentric with respect to the inner rotor,
  • the gear pump including a plurality of interdental chambers defined by two adjacent external teeth and two adjacent internal teeth, the teeth whose volume increases as the inner rotor and the outer rotor rotate.
  • One suction port that communicates with the interchamber, and a first and a second that are partitioned by a partition wall and are independent of each other, and communicate with the interdental chamber that decreases in volume as the inner rotor and the outer rotor rotate.
  • the volume change amount when the inner rotor is rotated by a unit angle and communicating with the suction port is maximum.
  • the minimum clearance between the external teeth and the internal teeth defining the interdental chamber is defined as a suction side clearance, and the first and second discharge ports when the volume change amount per unit angle becomes maximum.
  • the minimum clearance between the external teeth and the internal teeth that define an interdental chamber that at least partially overlaps the partition wall is defined as a discharge side clearance
  • the suction side clearance is more than the discharge side clearance. Is also large.
  • the inner rotor communicates with the suction port and has a minimum clearance between the external teeth and the internal teeth that define the interdental space that maximizes the volume change when the inner rotor rotates by a unit angle.
  • the clearance is formed so as to be larger than the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that at least partially overlaps the partition wall.
  • the flow of fluid between the first and second discharge ports is regulated to improve volumetric efficiency.
  • FIG. 1 is a schematic configuration diagram illustrating a gear pump 1 according to an embodiment of the present disclosure.
  • a gear pump 1 shown in the figure is configured as an oil pump mounted on a vehicle (not shown), for example, and sucks hydraulic oil (ATF) stored in an oil pan and pumps it to a hydraulic control device (both not shown).
  • the gear pump 1 is defined by, for example, a pump housing (both not shown) constituted by a pump body fixed to a transmission case of an automatic transmission and a pump cover fastened to the pump body, and the pump housing.
  • An inner rotor (drive gear) 2 and an outer rotor (driven gear) 3 that are rotatably arranged in a gear housing chamber (not shown).
  • the gear pump 1 may be configured as an in-vehicle pump (for example, an engine oil pump) other than an oil pump that pumps hydraulic oil for transmission, and may be applied to uses other than the in-vehicle pump.
  • the inner rotor 2 is fixed to a rotary shaft 4 connected to a crankshaft (both not shown) of an engine mounted on a vehicle, and is rotationally driven by power applied to the rotary shaft 4.
  • a plurality of (for example, 11 teeth in this embodiment) external teeth 20 are formed on the outer periphery of the inner rotor 2.
  • the number of internal teeth 30 that is one more than the total number of external teeth 20 of the inner rotor 2 (for example, 12 teeth in this embodiment) is formed.
  • the outer rotor 3 is rotatable in the gear housing chamber with a plurality of inner teeth 30 positioned on the lower side in FIG.
  • a plurality of interdental chambers (pump chambers) 5 are formed between the inner rotor 2 and the outer rotor 3 by two adjacent external teeth 20 and two adjacent internal teeth 30.
  • the outer rotor 3 has a part of the plurality of inner teeth 30 meshed with a part of the plurality of outer teeth 20.
  • the inner rotor 2 and the outer rotor 3 are rotated, in the rear region in the rotation direction of the both (see the thick arrow in FIG. 1), that is, mainly in the right half region in FIG.
  • the volume of each interdental chamber 5 increases (interdental chamber 5 expands).
  • the inner rotor 2 and the outer rotor 3 rotate, in the front region in the rotation direction of the inner rotor 2 or the like, that is, mainly the left half region in FIG.
  • the volume of the chamber 5 decreases (the interdental chamber 5 contracts).
  • the pump housing (not shown) of the gear pump 1 increases in volume as the inner rotor 2 and the outer rotor 3 among the plurality of interdental chambers 5 defined by the external teeth 20 and the internal teeth 30 rotate.
  • the volume decreases with the rotation of the suction port 6 extending in a substantially arc shape so as to communicate (oppose) with the interdental chamber 5 and the inner rotor 2 and the outer rotor 3 of the plurality of interdental chambers 5 respectively.
  • a first discharge port 7 and a second discharge port 8 extending in a substantially arc shape so as to communicate (oppose) with the interdental chamber 5 are formed.
  • the first and second discharge ports 7 and 8 are partitioned by a partition wall 9 and are independent of each other.
  • the first discharge port 7 located on the rear side in the rotation direction of the inner rotor 2 or the like is a low pressure port
  • the second discharge port 8 located on the front side in the rotation direction is a high pressure port.
  • the 1st and 2nd discharge ports 7 and 8 may be connected to a mutually different oil path, and may be connected to a common oil path.
  • the suction port 6, the first and second discharge ports 7, 8 may be formed on both sides (both the pump body and the pump cover) in the axial direction of the inner rotor 2 and the outer rotor 3,
  • the outer rotor 3 may be formed on one side (one of the pump body and the pump cover) in the axial direction.
  • the suction port 6 may be formed on one side in the axial direction of the inner rotor 2 or the like, and the first and second discharge ports 7 and 8 are formed on the other side in the axial direction of the inner rotor 2 or the like.
  • the first discharge port 7 may be formed on one side in the axial direction of the inner rotor 2 or the like
  • the second discharge port 8 may be formed on the other side in the axial direction of the inner rotor 2 or the like.
  • FIG. 2 is a schematic diagram showing a procedure for creating the inner teeth 30 of the outer rotor 3 included in the gear pump 1.
  • the tooth profile (outline) of the outer rotor 3 defined by the plurality of inner teeth 30 is a diameter 2 ⁇ e + t with the rotation center 2c of the inner rotor 2 being the center of the rotation center 3c of the outer rotor 3.
  • a plurality of tooth profile lines (inner rotors) obtained by rotating the inner rotor 2 by the rotation angle ⁇ / N when the rotation center 2c revolves by the predetermined angle ⁇ . 2 contours (refer to the two-dot chain line in FIG. 3).
  • t indicates that the rotation center 2 c of the inner rotor 2, the rotation center 3 c of the outer rotor 3, the top portion 21 t of the tooth tip portion 21 of the external tooth 20, and the top portion of the tooth tip portion of the internal tooth 30 are aligned.
  • the clearance (tip clearance) between the top 21t and the top of the internal tooth 30 is, for example, a value of about 0.03 to 0.07 mm.
  • the tooth profile (outline) of the outer rotor 3 may be the envelope itself or may be determined to be located outside the envelope.
  • the inner teeth of the outer rotor 3 may be created using a gear cutting tool having substantially the same shape as the inner rotor 2.
  • FIG. 3 is a schematic configuration diagram showing the external teeth 20 of the inner rotor 2
  • FIG. 4 is a schematic diagram showing a procedure for creating the external teeth 20.
  • each external tooth 20 of the inner rotor 2 includes a convexly curved tooth tip portion 21, a concave curved tooth bottom portion 22, and the rotational direction of the inner rotor 2 relative to the tooth tip portion 21 ( The first intermediate portion 23 located between the tooth tip portion 21 and the tooth bottom portion 22 on the front side in the thick arrow in FIG. 3, and the tooth on the rear side in the rotational direction of the inner rotor 2 relative to the tooth tip portion 21.
  • a second intermediate portion 24 located between the tip portion 21 and the tooth bottom portion 22 is included.
  • the external teeth 20 are formed asymmetrically with respect to a tooth profile center line Lc passing through the top portion 21t located on the outermost radial direction of the tooth tip portion 21 and the rotation center 2c of the inner rotor 2.
  • the tooth tip portion 21 has a trochoidal coefficient obtained by dividing the radius rde of the first drawing point by the radius re of the abduction circle Co, which is larger than 1 (for example, about 1.2). Value)
  • a convex curved surface is formed by an epitrochoid curve.
  • the epitrochoid curve forming the tooth tip portion 21 maintains the radius rde of the first drawing point at the first value Rde (constant value) and has an abduction circle Co having a radius re smaller than the first value Rde. Is rolled without slipping while circumscribing the base circle BCt having the rotation center 2c of the inner rotor 2 and the center O in common.
  • the tooth bottom portion 22 is formed in a concave curved surface by a hypotrochoidal curve having a trochoid coefficient larger than 1 obtained by dividing the radius rdh of the second drawing point by the radius rh of the inversion circle Ci.
  • the hypotrochoid curve forming the tooth bottom portion 22 is the same as the epitrochoid curve forming the tooth tip portion 21 and the basic circle BCt.
  • the radius rdh of the second drawing point is set to the first value. It is obtained by rolling an inversion circle Ci having a radius Rh smaller than the second value Rdh while keeping the value Rdh (constant value) 2 without slipping while inscribed in the basic circle BCt.
  • the tooth bottom portion 22 is a front side in the rotational direction from the tooth profile center line Lc by a half ( ⁇ / 2) of an angle ⁇ (360 ° / the number of teeth of the external teeth 20) corresponding to one tooth of the external teeth 20.
  • the first tooth bottom portion 22a located on the front side in the rotation direction of the inner rotor 2 with respect to the tooth tip portion 21 and the tooth tip portion 21 with respect to the intersection portion 22x with the line segment Le rotated rearward. It is divided into a second tooth bottom portion 22b located on the rear side in the rotation direction of the inner rotor 2.
  • a range between the two intersecting portions 22 x sandwiching the tooth profile center line Lc is a range corresponding to one tooth of the external teeth 20.
  • the second tooth bottom portion 22 b is continuous with the rear first tooth bottom portion 22 a in the rotation direction of the inner rotor 2.
  • the radius rde of the first drawing point for drawing the epitrochoid curve forming the tooth tip portion 21, that is, the first value Rde, and the hypotrochoid curve forming the tooth bottom portion 22 are drawn.
  • the radius rdh of the second drawing point that is, the second value Rdh is set to the same value Rd.
  • the first intermediate portion 23 is formed between the tooth tip portion 21 and the first tooth bottom portion 22 a of the tooth bottom portion 22, and is located on the tooth tip portion 21 side. And an inner intermediate portion 23i located on the first tooth bottom portion 22a side.
  • the outer intermediate portion 23o is such that the tangent at the front end 21f in the rotational direction of the inner rotor 2 of the tooth tip portion 21 is the same as the tangent of the epitrochoidal curve at the end 21f. It is formed by a defined involute curve. Thereby, the tip part 21 and the outer side intermediate part 23o can be smoothly continued in the edge part 21f.
  • the inner intermediate portion 23i is smoothly continuous with the first tooth bottom portion 22a at the rear end portion 22r in the rotation direction of the inner rotor 2 of the first tooth bottom portion 22a and is a boundary portion 23x with the outer intermediate portion 23o.
  • the outer intermediate portion 23o is formed by a smooth curve (for example, an arc) that is smoothly continuous. As shown in the drawing, the curve forming the inner intermediate portion 23i may be selected to be as short as possible than the involute curve forming the outer intermediate portion 23o.
  • the first intermediate portion 23 is formed by an involute curve (see Japanese Patent Application Laid-Open No. 2014-181620) obtained by using a basic circle having a center O in common with the basic circle BCt of the epitrochoid curve and the hypotrochoid curve. May be.
  • the diameter of the base circle of the involute curve forming the first intermediate portion 23 is “Rbi”
  • the diameter of the base circle BCt of the epitrochoid curve forming the tooth tip portion 21 and the hypotrochoid curve forming the tooth bottom portion 22 is set. Is set to “Rbt”
  • the diameters Rbt and Rbi may be selected so as to satisfy the relationship Rbi ⁇ Rbt.
  • the first intermediate portion 23 may include a relay surface formed by a smooth curve (for example, an arc) on the inner side (front side) and the outer side (rear side) of the portion formed by the involute curve.
  • the second intermediate portion 24 is formed between the tooth tip portion 21 and the second tooth bottom portion 22 b of the tooth bottom portion 22, and has teeth more than the intersection portion 24 x with the basic circle BCt.
  • intersection part 24x are included.
  • the gear pump 1 in order to improve the volumetric efficiency by regulating the flow of the hydraulic oil between the first and second discharge ports 7 and 8, the gear pump 1 It is necessary to make the minimum value of the clearance between the external teeth 20 and the internal teeth 30 overlapping with the partition wall 9 as small as possible when viewed from the axial direction of 1.
  • the external teeth 20 and the internal teeth 30 It is necessary to increase the minimum value of the clearance to allow the hydraulic oil to flow between the interdental chambers 5 adjacent to each other, thereby reducing the flow velocity of the hydraulic oil flowing from the suction port 6. Therefore, the inventors have determined the minimum clearance between the external teeth 20 and the internal teeth 30 between the first and second discharge ports 7 and 8 and the clearance between the external teeth 20 and the internal teeth 30 on the suction port 6 side. We conducted intensive research to optimize the minimum value.
  • volume change amount per unit angle hereinafter referred to as “volume change”. It has come to focus on "rate ⁇ V").
  • the internal pressure greatly decreases when the volume change rate ⁇ V becomes the maximum, and from the suction port 6 due to the decrease in the internal pressure. Cavitation tends to occur when hydraulic fluid flows at a high flow rate.
  • the minimum value of the clearance between the external teeth 20 and the internal teeth 30 that define the interdental chamber 5 that communicates with the intake port 6 and has the maximum volume change rate ⁇ V (hereinafter referred to as “intake side clearance” as appropriate). The smaller the amount, the lower the amount of pressure in the interdental chamber 5 (negative pressure) becomes larger when the volume change rate ⁇ V becomes maximum.
  • the plurality of external teeth 20 of the inner rotor 2 are in the ideal center state, and the minimum clearance (the clearance between the external teeth 20 and the internal teeth 30 that overlap the partition wall 9 when the volume change rate ⁇ V amount becomes maximum (
  • the suction side clearance is appropriately asymmetrical with respect to the tooth profile center line Lc so as to be larger than the “discharge side clearance”.
  • the rotation center c of the inner rotor 2 coincides with the rotation center of the rotation shaft 4 fixed to the inner rotor 2, and the rotation center c of the outer rotor 3 and the outer rotor 3 are accommodated.
  • the state where the center of the gear housing chamber matches.
  • the length of the curve forming the first intermediate portion 23 that is, the length from the end portion 21f of the tooth tip portion 21 to the end portion 22r of the first tooth bottom portion 22a.
  • the length is determined to be longer than the length of the curve forming the second intermediate portion 24, that is, the length from the end portion 21r of the tooth tip portion 21 to the end portion 22f of the second tooth bottom portion 22b.
  • the length of the hypotrochoid curve forming the first tooth bottom portion 22a that is, the length from the end 22r of the first tooth bottom portion 22a to the intersecting portion 22x is the length of the hypotrochoid curve forming the second tooth bottom portion 22b.
  • the length of the curve forming the first intermediate portion 23 is made longer than the length of the curve forming the second intermediate portion 24, and the length of the hypotrochoid curve forming the first tooth bottom portion 22a is set to the first length.
  • the end portion 21r on the rear side in the rotational direction of the epitrochoid curve forming the tooth tip portion 21 is made the second tooth bottom portion as shown in FIG. 22b, and the end portion 21f on the front side in the rotational direction of the epitrochoid curve can be moved outward in the radial direction of the inner rotor 2.
  • interdental chamber 5 connected to the 1st and 2nd discharge ports 7 and 8 by making the end part 21r on the back side in the rotation direction of the epitrochoid curve forming the tooth tip part 21 closer to the second tooth bottom part 22b.
  • the minimum value of the clearance between the outer teeth 20 and the inner teeth 30 that define the above can be reduced as a whole.
  • the minimum clearance between the teeth 20 and the internal teeth 30 can be increased as a whole.
  • the interdental chamber 5 that has reached the top dead center is positioned on the rear side in the rotation direction of the inner rotor 2. While any one external tooth 20 is in contact with the corresponding internal tooth 30, the external tooth 20 located on the one rear side in the rotation direction of the inner rotor 2 is located with respect to any one external tooth 20.
  • a plurality of external teeth 20 of the inner rotor 2 are formed so as to contact the corresponding internal teeth 30.
  • the position where the tooth tip apex 21t of the external tooth 20 and the tooth top apex of the internal tooth 30 face each other in a straight line through the top dead center (refer to the position between the suction port 6 and the first discharge port 7 in FIG. 7). While one of the outer teeth 20 closest to () is in contact with the corresponding inner tooth 30, the outer teeth 30 are positioned one rear side in the rotational direction of the inner rotor 2 with respect to any one of the outer teeth 30. The external teeth 20 come into contact with the corresponding internal teeth 30.
  • the “top dead center” is a position where the volume of the interdental chamber 5 that increases with the rotation of the inner rotor 2 or the like is maximized (position between the suction port 6 and the first discharge port 7 in FIG. 1).
  • the “decentered state from the ideal center state” means a deviation between the rotation center c of the inner rotor 2 and the rotation center of the rotation shaft 4 and a deviation between the rotation center c of the outer rotor 3 and the center of the gear housing chamber. A state in which at least one of them has occurred.
  • FIG. 5 illustrates the relationship between the rotation angle ⁇ around the rotation center 2 c of the inner rotor 2 in the gear pump 1 and the minimum value of the clearance between the outer teeth 20 and the inner teeth 30, and
  • FIG. 6 illustrates the rotation center of the inner rotor 2.
  • the relationship between the rotation angle ⁇ around 2c and the volume V and volume change rate ⁇ V of one interdental chamber 5 is illustrated.
  • the rotation angle ⁇ around the rotation center 2c of the inner rotor 2 is a rotation angle around the rotation center 2c of the line portion connecting the bottommost portion (deepest portion) of the tooth bottom portion 22 of the external tooth 20 and the rotation center 2c. 7 is measured counterclockwise in FIG. 7 when the state where the bottom of the bottom 22 of the external tooth 20 is located directly below the center of rotation 2c of the inner rotor 2 is 0 °.
  • a range A in FIG. 5 indicates a range in which the bottom part of the bottom part 22 of the external tooth 20 overlaps the partition wall 9.
  • the volume change rate ⁇ V shown in FIG. 6 is a change amount of the volume V when the rotation angle ⁇ changes (increases) by, for example, 5 °.
  • the minimum clearance CLd between the external teeth 20d and the internal teeth 30d overlapping the partition wall 9 is the discharge side clearance.
  • the minimum clearance CLi (suction side clearance) between the external teeth 20i and the internal teeth 30i is the minimum clearance CLd between the external teeth 20d and the internal teeth 30d overlapping the partition wall 9 (FIG. 5). 5 to 9 to 10 times as large as the value in the range A).
  • the minimum clearance shown in FIG. 5 is a design value (analysis value) in an ideal center state, and the minimum clearance between the external teeth 20 and the internal teeth 30 in the gear pump 1 as a product is a manufacturing tolerance or the like. Varies depending on In this regard, according to experiments and analysis by the present inventors, if the suction side clearance (CLi) in the product is at least three times or more than the discharge side clearance (CLd), the external teeth 20 overlapping the partition wall 9 are obtained. It has been confirmed that the minimum value of the clearance in the interdental chamber 5 where the volume change rate ⁇ V is maximized can be made sufficiently large in practice, while the minimum value of the clearance between the teeth 30 and the internal teeth 30 is sufficiently small in practice. Yes.
  • the gear pump 1 is one rear side in the rotational direction of any one of the external teeth 20.
  • the external teeth 20 positioned in the inner rotor 2 are configured to come into contact with the corresponding internal teeth 30.
  • the suction side clearance (CLi) is set. The upper limit of will be determined.
  • the gear pump 1 when the volume change rate ⁇ V of the interdental chamber 5m shown in FIG. 7 is maximized, the pair of external teeth 20d and internal teeth 30d overlap with the partition wall 9. Therefore, the external teeth 20d and internal teeth
  • the minimum clearance CLd with respect to 30d is set as the discharge-side clearance, but is not necessarily limited thereto. That is, the gear pump 1 may be configured such that the two sets of external teeth 20 and internal teeth 30 overlap the partition wall 9 when the volume change rate ⁇ V of the interdental chamber 5m is maximized. Of the minimum clearances of the outer teeth 20 and the inner teeth 30 in the set, the smaller one may be used as the discharge side clearance.
  • the discharge-side clearance is defined by the external teeth 20 and the internal teeth that define the interdental chamber 5 that at least partially overlaps the partition wall between the first and second discharge ports 7 and 8 when the volume change rate ⁇ V becomes maximum.
  • the minimum clearance with the teeth 30 may be set.
  • any one of the external teeth 20 closest to the top dead center is in contact with the corresponding internal tooth 30.
  • the external tooth 30 at the top dead center in the ideal rotation state in order to bring the external tooth 20 positioned one rear side in the rotational direction from any one of the external teeth 20 into contact with the corresponding internal tooth 30, the external tooth 30 at the top dead center in the ideal rotation state.
  • the tip clearance CLx (see FIG. 7) between the outer teeth 30 and the inner teeth 20 is set to the driving tooth surface of the outer teeth 30 located one rear side in the rotational direction with respect to the outer teeth 30 on the top dead center and the corresponding inner teeth 30.
  • the clearance with the driven tooth surface be equal to or greater than the minimum value CLy (see FIG. 7) in the ideal center state.
  • the tip clearance CLx between the outer teeth 30 and the inner teeth 20 at the top dead center in the ideal center state is preferably set to 200 ⁇ m or less.
  • the lower limit value of the tip clearance CLx in the ideal center state may be set to 5 ⁇ m or more in consideration of manufacturing tolerances.
  • Each external tooth 20 of the inner rotor 2 is asymmetrical so that the minimum value of the clearance in the interdental chamber 5 where the rate ⁇ V is maximum is increased.
  • the tooth tip portion 21 of each external tooth 20 of the inner rotor 2 is formed by a portion other than the loop portion of the epitrochoid curve having a trochoid coefficient larger than 1
  • the tooth bottom portion 22 is formed by the epitrochoid.
  • the curve and the base circle BCt are made common and formed by a portion other than the hypotrochoid curve loop in which the trochoid coefficient is larger than 1.
  • the shape of the tooth tip portion 21 and the tooth bottom portion 22 is determined using one basic circle BCt, and the outer diameter of the basic circle BCt, that is, the outer diameter of the inner rotor 2 is reduced. It is possible to easily increase the tooth height while maintaining it.
  • the first intermediate portion 23 positioned on the front side of the tooth tip portion 21 in the rotation direction of the inner rotor 2 is formed by an involute curve.
  • the outer teeth 20 of the inner rotor 2 and the inner teeth 30 of the outer rotor 3 can be meshed more smoothly and the rotational speed ratio between the inner rotor 2 and the outer rotor 3 can be made constant.
  • the first intermediate unit 23 is an involute curve such as an n-order function (where “n” is an integer of 1 or more), an arc, an arbitrary polynomial, a trigonometric function, a relaxation curve, and a combination thereof. Needless to say, it may be formed by other curves.
  • the range from the intersection 24x with the basic circle BCt of the second intermediate portion 24 to the end 21r of the tooth tip 21 changes to the basic circle BCt while changing the radius of the drawing point of the abduction circle Co. It is formed by a first curve obtained by rolling the circumscribed circle Co that circumscribes it without slipping. Further, the range from the intersection 24x of the second intermediate portion 24 with the basic circle BCt to the end 22f of the second tooth bottom portion 22b is inscribed in the basic circle BCt while changing the radius of the drawing point of the inversion circle Ci. It is formed by a second curve obtained by rolling the inward circle Ci without slipping.
  • the second intermediate portion smoothly connecting the tooth tip portion 21 and the second tooth bottom portion 22b while bringing the rear end portion 21r of the tooth tip portion 21 in the rotation direction of the inner rotor as close as possible to the second tooth bottom portion 22b.
  • the part 24 can be configured.
  • the second intermediate portion 24 is also an involute curve such as an n-order function (where “n” is an integer equal to or greater than 1), an arc, an arbitrary polynomial, a trigonometric function, a relaxation curve, and a combination thereof. Needless to say, it may be formed by other curves.
  • the gear pump according to the present disclosure has an inner rotor having a plurality of external teeth, a plurality of internal teeth that are larger than the external teeth of the inner rotor, and is arranged to be eccentric with respect to the inner rotor. And a plurality of interdental chambers defined by the two adjacent external teeth and the two adjacent internal teeth, with the rotation of the inner rotor and the outer rotor.
  • One suction port that communicates with the interdental chamber that increases in volume, and the interdental chamber that is partitioned by a partition wall and independent from each other, and the volume decreases as the inner rotor and the outer rotor rotate.
  • the minimum clearance between the external teeth and the internal teeth that defines the interdental chamber that maximizes the volume change amount is defined as the suction side clearance, and the volume change amount per unit angle is maximized when the volume change amount is maximized.
  • the suction side clearance when the minimum clearance between the external teeth and the internal teeth that define an interdental chamber that at least partially overlaps the partition wall between the first and second discharge ports is the discharge side clearance. Is larger than the discharge-side clearance.
  • This gear pump has one suction port and first and second discharge ports that are partitioned by a partition wall and independent from each other.
  • the flow of fluid between the first and second discharge ports is reduced by further reducing the minimum clearance between the external teeth and the internal teeth that overlap the partition between the first and second discharge ports.
  • the minimum clearance between the external teeth and the internal teeth is reduced from the viewpoint of suppressing the occurrence of cavitation due to the inflow (suction) of fluid from the suction port. It needs to be bigger.
  • the internal pressure greatly decreases when the volume change per unit angle becomes maximum. Cavitation is likely to occur due to the flow of fluid from the suction port at a high flow rate due to the decrease in the pressure.
  • the minimum clearance between the external teeth and the internal teeth that define the interdental space that maximizes the volume change amount when the inner rotor rotates by a unit angle while communicating with the suction port, that is, the suction side clearance is small. As the amount of decrease in the pressure in the interdental chamber (negative pressure) increases, the volume change amount per unit angle becomes maximum.
  • the inner rotor of this gear pump has an external tooth and an internal tooth that define an interdental space that at least partially overlaps the partition wall when the suction side clearance has a maximum volume change per unit angle.
  • the clearance is formed to be larger than the minimum value, that is, the discharge-side clearance.
  • the volume is determined based on the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that at least partially overlaps the partition wall.
  • the plurality of external teeth may be formed asymmetrically with respect to the tooth profile center line. Thereby, the suction side clearance can be easily made larger than the discharge side clearance.
  • the tooth profile center line may be a straight line connecting the top of the tooth tip and the rotation center of the inner rotor.
  • the suction side clearance may be at least three times the discharge side clearance.
  • the minimum clearance between the external teeth and the internal teeth overlapping the partition wall can be reduced.
  • the minimum value of the clearance in the interdental chamber where the volume change amount is maximized can be made sufficiently large in practice while being sufficiently small in practice. Thereby, it becomes possible to satisfactorily suppress the occurrence of cavitation in the interdental chamber communicating with the suction port while further improving the volumetric efficiency.
  • the tip clearance between the external teeth and the internal teeth when any one of the external teeth and the corresponding tooth tops of the internal teeth are positioned in a straight line is greater than that of any one of the external teeth.
  • the clearance may be equal to or greater than the minimum value of the clearance between the driving tooth surface of the external tooth positioned on the rear side in the rotation direction of the inner rotor and the driven tooth surface of the internal tooth corresponding thereto.
  • the tip clearance between any one of the outer teeth and the corresponding inner teeth may be 200 ⁇ m or less. Thereby, it is possible to suppress the increase in the discharge-side clearance and to regulate the fluid flow between the first and second discharge ports and to improve the volume efficiency.
  • each of the outer teeth of the inner rotor is a tooth tip formed by an epitrochoid curve obtained by rolling an outer rotation circle having a radius smaller than the drawing point radius without slipping while circumscribing the base circle.
  • a second tooth bottom portion continuous with the first tooth bottom portion on the rear side in the rotation direction, and an arbitrary curve, and the tooth tip portion and the first tooth bottom.
  • a first intermediate portion located between the first tip portion and the second root portion, and a first intermediate portion located between the first tip portion and the second bottom portion.
  • the length of the curve forming the intermediate portion may be longer than the length of the curve forming the second intermediate portion.
  • the minimum value of the clearance between the external teeth and the internal teeth that overlap the partition wall is made smaller, while the minimum clearance value in the interdental chamber that maximizes the volume change amount is reduced. It becomes possible to make it larger. That is, by making the length of the curve forming the first intermediate portion longer than the length of the curve forming the second intermediate portion, the end portion on the rear side in the rotation direction of the epitrochoid curve forming the tooth tip portion is The two tooth bottoms can be brought closer to each other, and the end portion on the front side in the rotational direction of the epitrochoid curve can be moved outward in the radial direction of the inner rotor.
  • the external teeth and internal teeth that overlap the partition wall It is possible to reduce the cavitation in the interdental chamber satisfactorily by making the minimum clearance value smaller and sufficiently increasing the minimum clearance value in the interdental chamber where the volume change is maximum.
  • one basic circle is used by increasing the radius of the epitrochoid curve and hypotrochoid curve while keeping the radius of the abduction circle and adduction circle (the radius of the basic circle / the number of teeth) small.
  • the shape of the tip portion and the bottom portion of the tooth can be determined, and the tooth height of the outer teeth can be easily increased while keeping the outer diameter of the basic circle, that is, the outer diameter of the inner rotor small.
  • the first intermediate part may be formed by at least an involute curve.
  • the range from the intersection of the second intermediate portion with the basic circle to the boundary with the tooth tip portion is the outer circumference circumscribing the basic circle while changing the radius of the drawing point of the abduction circle. It may be formed by a first curve obtained by rolling a rolling circle without slipping, and the range from the intersection of the second intermediate part with the basic circle to the boundary with the second tooth bottom is It may be formed by a second curve obtained by rolling the inversion circle inscribed in the basic circle without slipping while changing the radius of the drawing point of the inversion circle. Accordingly, the second intermediate portion that smoothly connects the tooth tip portion and the second tooth bottom portion while making the rear end portion of the tooth tip portion in the rotation direction of the inner rotor as close as possible to the second tooth bottom portion is configured. Is possible.
  • the tooth profile of the outer rotor defined by the plurality of inner teeth has an eccentricity amount of the rotation center of the outer rotor with respect to the rotation center of the inner rotor as “e”, and the rotation center of the inner rotor and the outer rotor Clearance between the tooth tip of the external tooth and the tooth tip of the internal tooth when the rotation center of the rotor, the top of the tooth tip of the external tooth and the top of the tooth tip of the internal tooth are positioned on a straight line Is set to “t”, the rotation center of the inner rotor is revolved by a predetermined angle on the circumference of the diameter 2 ⁇ e + t centering on the rotation center of the outer rotor, and the rotation center of the inner rotor is When revolving by an angle, the inner rotor is drawn with respect to a plurality of tooth profile lines obtained by rotating the inner rotor by the rotation angle corresponding to the predetermined angle and the number of teeth of the inner rotor. It may be determined based on ⁇ .
  • a manufacturing method of a gear pump includes an inner rotor having a plurality of external teeth, and an outer rotor having a plurality of inner teeth larger than the outer teeth of the inner rotor and arranged eccentric to the inner rotor.
  • a suction port that communicates with the chamber, and a first and a second that are partitioned by a partition wall and are independent of each other, and communicate with the interdental chamber that decreases in volume as the inner rotor and the outer rotor rotate.
  • a method for manufacturing a gear pump comprising a discharge port, wherein the inner rotor rotates at a unit angle while communicating with the suction port.
  • the minimum clearance between the external teeth and the internal teeth that define the interdental chamber where the amount of change is the maximum is the suction side clearance, and the first change when the volume change amount per unit angle is the maximum.
  • the suction side clearance is A step of forming the inner rotor so as to be larger than the discharge-side clearance;
  • the flow of fluid between the first and second discharge ports is restricted to improve the volumetric efficiency, and the occurrence of cavitation in the interdental chamber communicating with the suction port is suppressed. It becomes possible.
  • the invention of the present disclosure can be used in the gear pump manufacturing industry.

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Abstract

A plurality of external teeth 20 of an inner rotor 2 are formed such that the intake-side clearance CLi is greater than the discharge-side clearance CLd, where the intake-side clearance is the minimum value of clearance CLi between external teeth 20i and internal teeth 30i delineating an inter-tooth chamber 5 that is in communication with an intake port 6 and will demonstrate the largest change in volume when the inner rotor 2 rotates by a unit angle, and the discharge-side clearance CLd is the minimum value of clearance CLd between external teeth 20d and internal teeth 30d delineating an inter-tooth chamber 5 at least partially overlapping a partition wall 9 between first and second discharge ports 7, 8 when the change in volume per unit angle is largest.

Description

ギヤポンプおよびその製造方法Gear pump and manufacturing method thereof
　本開示は、複数の外歯を有するインナーロータと、複数の内歯を有すると共にインナーロータに対して偏心するように配置されるアウターロータとを含むギヤポンプおよびその製造方法に関する。 The present disclosure relates to a gear pump including an inner rotor having a plurality of external teeth and an outer rotor having a plurality of internal teeth and arranged to be eccentric with respect to the inner rotor, and a method for manufacturing the same.
　従来、ギヤポンプとして、外歯歯車の外歯と内歯歯車の内歯とにより画成されるポンプ室のうち、両歯車の回転により容積が増加するポンプ室（歯間室）に連通する１つの吸入ポートと、両歯車の回転により容積が減少するポンプ室に連通する２つの吐出ポートとを有するものが知られている（例えば、特許文献１参照）。このギヤポンプは、外歯歯車および内歯歯車が径方向の相反する方向に押圧された状態で、２つの吐出ポートを仕切る隔壁上に位置する外歯と内歯との最小隙間が０．０２０ｍｍ以上かつ０．１１０ｍｍ以下になるように設計されている。 Conventionally, as a gear pump, one of the pump chambers defined by the external teeth of the external gear and the internal teeth of the internal gear communicates with a pump chamber (interdental chamber) whose volume is increased by the rotation of both gears. One having a suction port and two discharge ports communicating with a pump chamber whose volume is reduced by the rotation of both gears is known (for example, see Patent Document 1). This gear pump has a minimum clearance of 0.020 mm or more between the external teeth and the internal teeth located on the partition wall that divides the two discharge ports in a state where the external gear and the internal gear are pressed in opposite directions in the radial direction. And it is designed to be 0.110 mm or less.
特許第５４６９８７５号公報Japanese Patent No. 5469875
　２つの吐出ポートを仕切る隔壁上に位置する外歯と内歯との最小隙間を上記従来のギヤポンプのように設定すれば、高圧側の一方の吐出ポートに連通するポンプ室から低圧側の他方の吐出ポートに連通するポンプ室への作動油の漏出を低減させてポンプの容積効率を改善することができるであろう。しかしながら、隔壁上に位置する外歯と内歯との最小隙間を小さくすると、吸入ポートに連通するポンプ室に流体が流入する際にキャビテーションが発生してしまい、それにより容積効率が低下してしまったり、ノイズや振動が発生してしまったりするおそれがある。 If the minimum gap between the external teeth and the internal teeth located on the partition wall that divides the two discharge ports is set as in the conventional gear pump, the pump chamber communicating with one discharge port on the high pressure side and the other on the low pressure side It would be possible to improve the volumetric efficiency of the pump by reducing the leakage of hydraulic oil to the pump chamber communicating with the discharge port. However, if the minimum clearance between the external teeth and the internal teeth located on the partition wall is reduced, cavitation occurs when fluid flows into the pump chamber communicating with the suction port, thereby reducing volumetric efficiency. There is a risk of noise or vibration.
　そこで、本開示の発明は、容積効率の向上を図りつつ、キャビテーションの発生を抑制することができるギヤポンプおよびその製造方法の提供を主目的とする。 Therefore, the main object of the present disclosure is to provide a gear pump that can suppress the occurrence of cavitation while improving volumetric efficiency, and a method for manufacturing the same.
　本開示のギヤポンプは、複数の外歯を有するインナーロータと、前記インナーロータの前記外歯よりも多い複数の内歯を有すると共に該インナーロータに対して偏心するように配置されるアウターロータと、隣り合う２つの前記外歯と隣り合う２つの前記内歯とにより画成される複数の歯間室とを含むギヤポンプにおいて、前記インナーロータおよび前記アウターロータの回転に伴って容積が増加する前記歯間室に連通する１つの吸入ポートと、隔壁により仕切られて互いに独立しており、それぞれ前記インナーロータおよび前記アウターロータの回転に伴って容積が減少する前記歯間室に連通する第１および第２吐出ポートとを備え、前記吸入ポートに連通すると共に前記インナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吸入側クリアランスとし、前記単位角度あたりの前記容積変化量が最大となる際に前記第１および第２吐出ポートの間で前記隔壁と少なくとも部分的に重なり合う歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吐出側クリアランスとしたときに、前記吸入側クリアランスが前記吐出側クリアランスよりも大きいことを特徴とする。 A gear pump of the present disclosure includes an inner rotor having a plurality of external teeth, an outer rotor having a plurality of internal teeth larger than the external teeth of the inner rotor and arranged to be eccentric with respect to the inner rotor, In the gear pump including a plurality of interdental chambers defined by two adjacent external teeth and two adjacent internal teeth, the teeth whose volume increases as the inner rotor and the outer rotor rotate. One suction port that communicates with the interchamber, and a first and a second that are partitioned by a partition wall and are independent of each other, and communicate with the interdental chamber that decreases in volume as the inner rotor and the outer rotor rotate. 2 discharge ports, the volume change amount when the inner rotor is rotated by a unit angle and communicating with the suction port is maximum. The minimum clearance between the external teeth and the internal teeth defining the interdental chamber is defined as a suction side clearance, and the first and second discharge ports when the volume change amount per unit angle becomes maximum When the minimum clearance between the external teeth and the internal teeth that define an interdental chamber that at least partially overlaps the partition wall is defined as a discharge side clearance, the suction side clearance is more than the discharge side clearance. Is also large.
　このギヤポンプにおいて、インナーロータは、吸入ポートに連通すると共にインナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する外歯と内歯とのクリアランスの最小値が、単位角度あたりの容積変化量が最大になる際に隔壁と少なくとも部分的に重なり合う歯間室を画成する外歯と内歯とのクリアランスの最小値よりも大きくなるように形成される。このように、吸入ポートに連通する歯間室の容積変化を考慮して、隔壁と少なくとも部分的に重なり合う歯間室を画成する外歯と内歯とのクリアランスの最小値を基に、容積変化量が最大となる歯間室におけるクリアランスの最小値が大きくなるようにインナーロータを形成することで、第１および第２吐出ポート間での流体の流通を規制して容積効率の向上を図りつつ、吸入ポートに連通する歯間室でのキャビテーションの発生を抑制することが可能となる。 In this gear pump, the inner rotor communicates with the suction port and has a minimum clearance between the external teeth and the internal teeth that define the interdental space that maximizes the volume change when the inner rotor rotates by a unit angle. When the volume change amount per unit angle is maximized, the clearance is formed so as to be larger than the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that at least partially overlaps the partition wall. Thus, taking into account the volume change of the interdental chamber communicating with the suction port, the volume is determined based on the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that at least partially overlaps the partition wall. By forming the inner rotor so that the minimum value of the clearance in the interdental chamber where the amount of change is maximum is increased, the flow of fluid between the first and second discharge ports is regulated to improve volumetric efficiency. However, it is possible to suppress the occurrence of cavitation in the interdental chamber communicating with the suction port.
本開示のギヤポンプを示す概略構成図である。It is a schematic structure figure showing a gear pump of this indication. 本開示のギヤポンプに含まれるアウターロータの内歯の創成手順を示す模式図である。It is a schematic diagram which shows the creation procedure of the internal tooth of the outer rotor contained in the gear pump of this indication. 本開示のギヤポンプに含まれるインナーロータの外歯を示す概略構成図である。It is a schematic block diagram which shows the external tooth of the inner rotor contained in the gear pump of this indication. 本開示のギヤポンプに含まれるインナーロータの外歯の創成手順を示す模式図である。It is a schematic diagram which shows the creation procedure of the external tooth of the inner rotor contained in the gear pump of this indication. インナーロータの回転中心周りの回転角度と、外歯および内歯のクリアランスの最小値との関係を例示する図表である。It is a graph which illustrates the relationship between the rotation angle around the rotation center of an inner rotor, and the minimum value of the clearance of an external tooth and an internal tooth. インナーロータの回転中心周りの回転角度と、１つの歯間室の容積および容積変化率との関係を例示する図表である。It is a graph which illustrates the relationship between the rotation angle around the rotation center of an inner rotor, the volume of one interdental chamber, and the volume change rate. 容積変化率が最大となる歯間室を画成する外歯と内歯とのクリアランスの最小値と、隔壁と重なり合う外歯と内歯とのクリアランスの最小値を例示する概略構成図である。It is a schematic block diagram which illustrates the minimum value of the clearance between the external tooth and the internal tooth which defines the interdental chamber where the volume change rate becomes the maximum, and the minimum value of the clearance between the external tooth and the internal tooth which overlaps the partition wall.
　次に、図面を参照しながら、本開示の発明を実施するための形態について説明する。 Next, an embodiment for carrying out the invention of the present disclosure will be described with reference to the drawings.
　図１は、本開示の一実施形態に係るギヤポンプ１を示す概略構成図である。同図に示すギヤポンプ１は、例えば図示しない車両に搭載されるオイルポンプとして構成され、オイルパンに貯留されている作動油（ＡＴＦ）を吸引して油圧制御装置（何れも図示省略）へと圧送するものである。ギヤポンプ１は、例えば自動変速機の変速機ケースに固定されるポンプボディと当該ポンプボディに締結されるポンプカバーとにより構成されるポンプハウジング（何れも図示省略）と、当該ポンプハウジングにより画成される図示しないギヤ収容室内にそれぞれ回転自在に配置されるインナーロータ（ドライブギヤ）２およびアウターロータ（ドリブンギヤ）３とを含む。なお、ギヤポンプ１は、変速機用の作動油を圧送するオイルポンプ以外の車載ポンプ（例えば、エンジンオイルポンプ）として構成されてもよく、車載ポンプ以外の用途に適用されてもよい。 FIG. 1 is a schematic configuration diagram illustrating a gear pump 1 according to an embodiment of the present disclosure. A gear pump 1 shown in the figure is configured as an oil pump mounted on a vehicle (not shown), for example, and sucks hydraulic oil (ATF) stored in an oil pan and pumps it to a hydraulic control device (both not shown). To do. The gear pump 1 is defined by, for example, a pump housing (both not shown) constituted by a pump body fixed to a transmission case of an automatic transmission and a pump cover fastened to the pump body, and the pump housing. An inner rotor (drive gear) 2 and an outer rotor (driven gear) 3 that are rotatably arranged in a gear housing chamber (not shown). The gear pump 1 may be configured as an in-vehicle pump (for example, an engine oil pump) other than an oil pump that pumps hydraulic oil for transmission, and may be applied to uses other than the in-vehicle pump.
　インナーロータ２は、車両に搭載されたエンジンのクランクシャフト（何れも図示省略）に連結される回転軸４に固定され、当該回転軸４に付与される動力により回転駆動される。また、インナーロータ２の外周には、複数（本実施形態では、例えば１１歯）の外歯２０が形成されている。一方、アウターロータ３の内周には、インナーロータ２の外歯２０の総数よりも１つ多い数（本実施形態では、例えば１２歯）の内歯３０が形成されている。アウターロータ３は、図１における下側に位置する複数の内歯３０がインナーロータ２の対応する外歯２０に噛合すると共に、インナーロータ２に対して偏心した状態で上記ギヤ収容室内に回転自在に配置される。更に、インナーロータ２とアウターロータ３との間には、隣り合う２つの外歯２０と隣り合う２つの内歯３０とにより複数の歯間室（ポンプ室）５が形成される。 The inner rotor 2 is fixed to a rotary shaft 4 connected to a crankshaft (both not shown) of an engine mounted on a vehicle, and is rotationally driven by power applied to the rotary shaft 4. A plurality of (for example, 11 teeth in this embodiment) external teeth 20 are formed on the outer periphery of the inner rotor 2. On the other hand, on the inner periphery of the outer rotor 3, the number of internal teeth 30 that is one more than the total number of external teeth 20 of the inner rotor 2 (for example, 12 teeth in this embodiment) is formed. The outer rotor 3 is rotatable in the gear housing chamber with a plurality of inner teeth 30 positioned on the lower side in FIG. 1 meshing with the corresponding outer teeth 20 of the inner rotor 2 and eccentric with respect to the inner rotor 2. Placed in. Further, a plurality of interdental chambers (pump chambers) 5 are formed between the inner rotor 2 and the outer rotor 3 by two adjacent external teeth 20 and two adjacent internal teeth 30.
　これにより、回転軸４からの動力によりインナーロータ２が図１における太線矢印方向に回転すると、アウターロータ３は、複数の内歯３０の一部が複数の外歯２０の一部に噛合することで、インナーロータ２の回転中心２ｃから偏心量ｅだけ離間した回転中心３ｃの周りにインナーロータ２と共に同方向に回転する。インナーロータ２およびアウターロータ３が回転する際、両者の回転方向（図１における太線矢印参照）における後側の領域、すなわち図１における主に右側半分の領域では、インナーロータ２等の回転に伴って各歯間室５の容積が増加（歯間室５が膨張）する。また、インナーロータ２およびアウターロータ３が回転する際、インナーロータ２等の回転方向における前側の領域、すなわち図１における主に左側半分の領域では、インナーロータ２等の回転に伴って各歯間室５の容積が減少（歯間室５が収縮）する。 Thereby, when the inner rotor 2 is rotated in the direction of the thick arrow in FIG. 1 by the power from the rotating shaft 4, the outer rotor 3 has a part of the plurality of inner teeth 30 meshed with a part of the plurality of outer teeth 20. Thus, it rotates in the same direction together with the inner rotor 2 around the rotation center 3c that is separated from the rotation center 2c of the inner rotor 2 by the eccentric amount e. When the inner rotor 2 and the outer rotor 3 are rotated, in the rear region in the rotation direction of the both (see the thick arrow in FIG. 1), that is, mainly in the right half region in FIG. Thus, the volume of each interdental chamber 5 increases (interdental chamber 5 expands). Further, when the inner rotor 2 and the outer rotor 3 rotate, in the front region in the rotation direction of the inner rotor 2 or the like, that is, mainly the left half region in FIG. The volume of the chamber 5 decreases (the interdental chamber 5 contracts).
　また、ギヤポンプ１の図示しないポンプハウジングには、外歯２０と内歯３０とにより画成される複数の歯間室５のうちのインナーロータ２およびアウターロータ３の回転に伴って容積が増加する歯間室５と連通（対向）するように略円弧状に延在する吸入ポート６や、それぞれ複数の歯間室５のうちのインナーロータ２およびアウターロータ３の回転に伴って容積が減少する歯間室５と連通（対向）するように略円弧状に延在する第１吐出ポート７および第２吐出ポート８が形成されている。第１および第２吐出ポート７，８は、図示するように、隔壁９により仕切られて互いに独立している。本実施形態では、インナーロータ２等の回転方向における後側に位置する第１吐出ポート７が低圧ポートとされ、当該回転方向における前側に位置する第２吐出ポート８が高圧ポートとされる。 Further, the pump housing (not shown) of the gear pump 1 increases in volume as the inner rotor 2 and the outer rotor 3 among the plurality of interdental chambers 5 defined by the external teeth 20 and the internal teeth 30 rotate. The volume decreases with the rotation of the suction port 6 extending in a substantially arc shape so as to communicate (oppose) with the interdental chamber 5 and the inner rotor 2 and the outer rotor 3 of the plurality of interdental chambers 5 respectively. A first discharge port 7 and a second discharge port 8 extending in a substantially arc shape so as to communicate (oppose) with the interdental chamber 5 are formed. As illustrated, the first and second discharge ports 7 and 8 are partitioned by a partition wall 9 and are independent of each other. In the present embodiment, the first discharge port 7 located on the rear side in the rotation direction of the inner rotor 2 or the like is a low pressure port, and the second discharge port 8 located on the front side in the rotation direction is a high pressure port.
　なお、第１および第２吐出ポート７，８は、互いに異なる油路に接続されてもよく、共通の油路に接続されてもよい。また、吸入ポート６、第１および第２吐出ポート７，８は、インナーロータ２およびアウターロータ３の軸方向における両側（ポンプボディおよびポンプカバーの双方）に形成されてもよく、インナーロータ２およびアウターロータ３の軸方向における片側（ポンプボディおよびポンプカバーの一方）に形成されてもよい。また、例えば、吸入ポート６がインナーロータ２等の軸方向における一方側に形成されてもよく、第１および第２吐出ポート７，８がインナーロータ２等の軸方向における他方側に形成されてもよい。更に、第１吐出ポート７がインナーロータ２等の軸方向における一方側に形成されてもよく、第２吐出ポート８がインナーロータ２等の軸方向における他方側に形成されてもよい。 In addition, the 1st and 2nd discharge ports 7 and 8 may be connected to a mutually different oil path, and may be connected to a common oil path. The suction port 6, the first and second discharge ports 7, 8 may be formed on both sides (both the pump body and the pump cover) in the axial direction of the inner rotor 2 and the outer rotor 3, The outer rotor 3 may be formed on one side (one of the pump body and the pump cover) in the axial direction. Further, for example, the suction port 6 may be formed on one side in the axial direction of the inner rotor 2 or the like, and the first and second discharge ports 7 and 8 are formed on the other side in the axial direction of the inner rotor 2 or the like. Also good. Further, the first discharge port 7 may be formed on one side in the axial direction of the inner rotor 2 or the like, and the second discharge port 8 may be formed on the other side in the axial direction of the inner rotor 2 or the like.
　図２は、ギヤポンプ１に含まれるアウターロータ３の内歯３０の創成手順を示す模式図である。同図に示すように、複数の内歯３０により画成されるアウターロータ３の歯形（輪郭）は、インナーロータ２の回転中心２ｃをアウターロータ３の回転中心３ｃを中心とする直径２・ｅ＋ｔの円周上で所定角度δずつ１周公転させると共に、回転中心２ｃが所定角度δだけ公転する際にインナーロータ２を回転角度δ／Ｎだけ自転させることにより得られる複数の歯形線（インナーロータ２の輪郭、図３における二点鎖線参照）に対して描かれる包絡線に基づいて定められる。ただし、“ｔ”は、インナーロータ２の回転中心２ｃ、アウターロータ３の回転中心３ｃ、外歯２０の歯先部２１の頂部２１ｔおよび内歯３０の歯先部の頂部が一直線上に位置する際の頂部２１ｔと内歯３０の頂部とのクリアランス（チップクリアランス）であり、例えば、０．０３～０．０７ｍｍ程度の値とされる。これにより、インナーロータ２と適正に噛合可能なアウターロータ３を容易に得ることが可能となる。ただし、アウターロータ３の歯形（輪郭）は、上記包絡線自体であってもよく、当該包絡線よりも外側に位置するように定められてもよい。また、アウターロータ３の内歯は、インナーロータ２と概ね同一の形状を有する歯切工具を用いて創成されてもよい。 FIG. 2 is a schematic diagram showing a procedure for creating the inner teeth 30 of the outer rotor 3 included in the gear pump 1. As shown in the figure, the tooth profile (outline) of the outer rotor 3 defined by the plurality of inner teeth 30 is a diameter 2 · e + t with the rotation center 2c of the inner rotor 2 being the center of the rotation center 3c of the outer rotor 3. And a plurality of tooth profile lines (inner rotors) obtained by rotating the inner rotor 2 by the rotation angle δ / N when the rotation center 2c revolves by the predetermined angle δ. 2 contours (refer to the two-dot chain line in FIG. 3). However, “t” indicates that the rotation center 2 c of the inner rotor 2, the rotation center 3 c of the outer rotor 3, the top portion 21 t of the tooth tip portion 21 of the external tooth 20, and the top portion of the tooth tip portion of the internal tooth 30 are aligned. The clearance (tip clearance) between the top 21t and the top of the internal tooth 30 is, for example, a value of about 0.03 to 0.07 mm. As a result, it is possible to easily obtain the outer rotor 3 that can mesh properly with the inner rotor 2. However, the tooth profile (outline) of the outer rotor 3 may be the envelope itself or may be determined to be located outside the envelope. The inner teeth of the outer rotor 3 may be created using a gear cutting tool having substantially the same shape as the inner rotor 2.
　図３は、インナーロータ２の外歯２０を示す概略構成図であり、図４は、外歯２０の創成手順を示す模式図である。これらの図面に示すように、インナーロータ２の各外歯２０は、凸曲面状の歯先部２１と、凹曲面状の歯底部２２と、歯先部２１よりもインナーロータ２の回転方向（図３における太線矢印参照）における前側で当該歯先部２１と歯底部２２との間に位置する第１中間部２３と、歯先部２１よりもインナーロータ２の回転方向における後側で当該歯先部２１と歯底部２２との間に位置する第２中間部２４とを含む。図示するように、外歯２０は、歯先部２１の最も径方向外側に位置する頂部２１ｔとインナーロータ２の回転中心２ｃを通る歯形中心線Ｌｃに関して左右非対称に形成される。 FIG. 3 is a schematic configuration diagram showing the external teeth 20 of the inner rotor 2, and FIG. 4 is a schematic diagram showing a procedure for creating the external teeth 20. As shown in these drawings, each external tooth 20 of the inner rotor 2 includes a convexly curved tooth tip portion 21, a concave curved tooth bottom portion 22, and the rotational direction of the inner rotor 2 relative to the tooth tip portion 21 ( The first intermediate portion 23 located between the tooth tip portion 21 and the tooth bottom portion 22 on the front side in the thick arrow in FIG. 3, and the tooth on the rear side in the rotational direction of the inner rotor 2 relative to the tooth tip portion 21. A second intermediate portion 24 located between the tip portion 21 and the tooth bottom portion 22 is included. As shown in the drawing, the external teeth 20 are formed asymmetrically with respect to a tooth profile center line Lc passing through the top portion 21t located on the outermost radial direction of the tooth tip portion 21 and the rotation center 2c of the inner rotor 2.
　歯先部２１は、図４に示すように、第１の描画点の半径ｒｄｅを外転円Ｃｏの半径ｒｅで除して得られるトロコイド係数が値１よりも大きい（例えば１．２程度の値）エピトロコイド曲線により凸曲面状に形成される。歯先部２１を形成するエピトロコイド曲線は、第１の描画点の半径ｒｄｅを第１の値Ｒｄｅ（一定値）に保つと共に当該第１の値Ｒｄｅよりも小さい半径ｒｅを有する外転円Ｃｏをインナーロータ２の回転中心２ｃと中心Ｏを共通にする基礎円ＢＣｔに外接させながら滑りなく転動させることにより得られる。 As shown in FIG. 4, the tooth tip portion 21 has a trochoidal coefficient obtained by dividing the radius rde of the first drawing point by the radius re of the abduction circle Co, which is larger than 1 (for example, about 1.2). Value) A convex curved surface is formed by an epitrochoid curve. The epitrochoid curve forming the tooth tip portion 21 maintains the radius rde of the first drawing point at the first value Rde (constant value) and has an abduction circle Co having a radius re smaller than the first value Rde. Is rolled without slipping while circumscribing the base circle BCt having the rotation center 2c of the inner rotor 2 and the center O in common.
　歯底部２２は、第２の描画点の半径ｒｄｈを内転円Ｃｉの半径ｒｈで除して得られるトロコイド係数が値１よりも大きいハイポトロコイド曲線により凹曲面状に形成される。歯底部２２を形成するハイポトロコイド曲線は、歯先部２１を形成するエピトロコイド曲線と基礎円ＢＣｔを共通にするものであり、図４に示すように、第２の描画点の半径ｒｄｈを第２の値Ｒｄｈ（一定値）に保つと共に当該第２の値Ｒｄｈよりも小さい半径ｒｈを有する内転円Ｃｉを上記基礎円ＢＣｔに内接させながら滑りなく転動させることにより得られる。 The tooth bottom portion 22 is formed in a concave curved surface by a hypotrochoidal curve having a trochoid coefficient larger than 1 obtained by dividing the radius rdh of the second drawing point by the radius rh of the inversion circle Ci. The hypotrochoid curve forming the tooth bottom portion 22 is the same as the epitrochoid curve forming the tooth tip portion 21 and the basic circle BCt. As shown in FIG. 4, the radius rdh of the second drawing point is set to the first value. It is obtained by rolling an inversion circle Ci having a radius Rh smaller than the second value Rdh while keeping the value Rdh (constant value) 2 without slipping while inscribed in the basic circle BCt.
　また、歯底部２２は、外歯２０の一歯分に対応した角度φ（３６０°／外歯２０の歯数）の二分の１（φ／２）だけ歯形中心線Ｌｃから上記回転方向の前側または後側に回転させられた線分Ｌｅとの交差部２２ｘを境に、歯先部２１よりもインナーロータ２の回転方向における前側に位置する第１歯底部２２ａと、歯先部２１よりもインナーロータ２の回転方向における後側に位置する第２歯底部２２ｂとに区分される。そして、インナーロータ２では、図３および図４に示すように、歯形中心線Ｌｃを挟む２つの交差部２２ｘ間の範囲が外歯２０の一歯分の範囲とされる。第２歯底部２２ｂは、図３および図４に示すように、インナーロータ２の回転方向における後側の第１歯底部２２ａに連続する。 Further, the tooth bottom portion 22 is a front side in the rotational direction from the tooth profile center line Lc by a half (φ / 2) of an angle φ (360 ° / the number of teeth of the external teeth 20) corresponding to one tooth of the external teeth 20. Alternatively, the first tooth bottom portion 22a located on the front side in the rotation direction of the inner rotor 2 with respect to the tooth tip portion 21 and the tooth tip portion 21 with respect to the intersection portion 22x with the line segment Le rotated rearward. It is divided into a second tooth bottom portion 22b located on the rear side in the rotation direction of the inner rotor 2. In the inner rotor 2, as shown in FIGS. 3 and 4, a range between the two intersecting portions 22 x sandwiching the tooth profile center line Lc is a range corresponding to one tooth of the external teeth 20. As shown in FIGS. 3 and 4, the second tooth bottom portion 22 b is continuous with the rear first tooth bottom portion 22 a in the rotation direction of the inner rotor 2.
　また、本実施形態において、歯先部２１を形成するエピトロコイド曲線を描画するための第１の描画点の半径ｒｄｅすなわち第１の値Ｒｄｅと、歯底部２２を形成するハイポトロコイド曲線を描画するための第２の描画点の半径ｒｄｈすなわち第２の値Ｒｄｈとは、同一の値Ｒｄに定められている。同様に、外転円Ｃｏの半径ｒｅおよび内転円Ｃｉの半径ｒｈも同一の値Ｒに定められている。従って、インナーロータ２では、Ｒｄｅ＝Ｒｄｈ＝Ｒｄ、ｒｅ＝ｒｈ＝Ｒ、歯丈＝Ｒｄｅ＋ｒｅ＋Ｒｄｈ＋ｒｈ＝２・ｅという関係が成立する。 In the present embodiment, the radius rde of the first drawing point for drawing the epitrochoid curve forming the tooth tip portion 21, that is, the first value Rde, and the hypotrochoid curve forming the tooth bottom portion 22 are drawn. For this reason, the radius rdh of the second drawing point, that is, the second value Rdh is set to the same value Rd. Similarly, the radius re of the abduction circle Co and the radius rh of the inversion circle Ci are set to the same value R. Therefore, in the inner rotor 2, the relationship Rde = Rdh = Rd, re = rh = R, and tooth height = Rde + re + Rdh + rh = 2 · e is established.
　第１中間部２３は、図３および図４に示すように、歯先部２１と歯底部２２の第１歯底部２２ａとの間に形成され、歯先部２１側に位置する外側中間部２３ｏと、第１歯底部２２ａ側に位置する内側中間部２３ｉとを含む。本実施形態において、外側中間部２３ｏは、歯先部２１のインナーロータ２の回転方向における前側の端部２１ｆでの接線が当該端部２１ｆでの上記エピトロコイド曲線の接線と共通になるように定められたインボリュート曲線により形成される。これにより、端部２１ｆにおいて歯先部２１と外側中間部２３ｏとを滑らかに連続させることができる。また、内側中間部２３ｉは、第１歯底部２２ａのインナーロータ２の回転方向における後側の端部２２ｒで当該第１歯底部２２ａに滑らかに連続すると共に外側中間部２３ｏとの境界部２３ｘで当該外側中間部２３ｏと滑らかに連続する滑らかな曲線（例えば円弧）により形成される。図示するように、内側中間部２３ｉを形成する曲線は、外側中間部２３ｏを形成するインボリュート曲線よりもできるだけ短くなるように選択されるとよい。 As shown in FIGS. 3 and 4, the first intermediate portion 23 is formed between the tooth tip portion 21 and the first tooth bottom portion 22 a of the tooth bottom portion 22, and is located on the tooth tip portion 21 side. And an inner intermediate portion 23i located on the first tooth bottom portion 22a side. In the present embodiment, the outer intermediate portion 23o is such that the tangent at the front end 21f in the rotational direction of the inner rotor 2 of the tooth tip portion 21 is the same as the tangent of the epitrochoidal curve at the end 21f. It is formed by a defined involute curve. Thereby, the tip part 21 and the outer side intermediate part 23o can be smoothly continued in the edge part 21f. Further, the inner intermediate portion 23i is smoothly continuous with the first tooth bottom portion 22a at the rear end portion 22r in the rotation direction of the inner rotor 2 of the first tooth bottom portion 22a and is a boundary portion 23x with the outer intermediate portion 23o. The outer intermediate portion 23o is formed by a smooth curve (for example, an arc) that is smoothly continuous. As shown in the drawing, the curve forming the inner intermediate portion 23i may be selected to be as short as possible than the involute curve forming the outer intermediate portion 23o.
　なお、第１中間部２３は、上記エピトロコイド曲線およびハイポトロコイド曲線の基礎円ＢＣｔと中心Ｏを共通にする基礎円を用いて得られるインボリュート曲線（特開２０１４－１８１６２０号公報参照）により形成されてもよい。この場合、第１中間部２３を形成するインボリュート曲線の基礎円の直径を“Ｒｂｉ”とし、歯先部２１を形成するエピトロコイド曲線および歯底部２２を形成するハイポトロコイド曲線の基礎円ＢＣｔの直径を“Ｒｂｔ”としたときに、直径Ｒｂｔ，Ｒｂｉは、Ｒｂｉ≦Ｒｂｔという関係を満たすように選択されるとよい。また、この場合、第１中間部２３は、当該インボリュート曲線により形成される部分の内側（前側）および外側（後側）に滑らかな曲線（例えば円弧）により形成される中継面を含むとよい。 The first intermediate portion 23 is formed by an involute curve (see Japanese Patent Application Laid-Open No. 2014-181620) obtained by using a basic circle having a center O in common with the basic circle BCt of the epitrochoid curve and the hypotrochoid curve. May be. In this case, the diameter of the base circle of the involute curve forming the first intermediate portion 23 is “Rbi”, and the diameter of the base circle BCt of the epitrochoid curve forming the tooth tip portion 21 and the hypotrochoid curve forming the tooth bottom portion 22 is set. Is set to “Rbt”, the diameters Rbt and Rbi may be selected so as to satisfy the relationship Rbi ≦ Rbt. In this case, the first intermediate portion 23 may include a relay surface formed by a smooth curve (for example, an arc) on the inner side (front side) and the outer side (rear side) of the portion formed by the involute curve.
　第２中間部２４は、図３および図４に示すように、歯先部２１と歯底部２２の第２歯底部２２ｂとの間に形成され、上記基礎円ＢＣｔとの交差部２４ｘよりも歯先部２１側に位置する外側中間部２４ｏと、交差部２４ｘよりも第２歯底部２２ｂ側に位置する内側中間部２４ｉとを含む。本実施形態において、外側中間部２４ｏ、すなわち交差部２４ｘから歯先部２１のインナーロータ２の回転方向における後側の端部（境界）２１ｒまでの範囲は、図４に示すように、上記第１描画点の半径（図中点線参照）を変化させながら基礎円ＢＣｔに外接する外転円Ｃｏを滑りなく転動させて得られる第１の曲線により形成される。また、内側中間部２４ｉ、すなわち交差部２４ｘから第２歯底部２２ｂのインナーロータ２の回転方向における前側の端部（境界）２２ｆまでの範囲は、図４に示すように、上記第２描画点の半径（図中二点鎖線参照）を変化させながら基礎円ＢＣｔに内接する内転円Ｃｉを滑りなく転動させて得られる第２の曲線により形成される。なお、外転円Ｃｏや内転円Ｃｉの第１または第２描画点の半径を変化させる手順については、特開２０１４－１８１６１９号公報を参照されたい。 As shown in FIGS. 3 and 4, the second intermediate portion 24 is formed between the tooth tip portion 21 and the second tooth bottom portion 22 b of the tooth bottom portion 22, and has teeth more than the intersection portion 24 x with the basic circle BCt. The outer intermediate part 24o located in the front part 21 side and the inner intermediate part 24i located in the 2nd tooth bottom part 22b side rather than the cross | intersection part 24x are included. In the present embodiment, the range from the outer intermediate portion 24o, that is, the intersecting portion 24x to the rear end portion (boundary) 21r in the rotation direction of the inner rotor 2 of the tooth tip portion 21, as shown in FIG. It is formed by a first curve obtained by rolling an outer rotation circle Co circumscribing the base circle BCt without slipping while changing the radius of one drawing point (see the dotted line in the figure). Further, the range from the inner intermediate portion 24i, that is, the intersecting portion 24x to the front end portion (boundary) 22f in the rotation direction of the inner rotor 2 of the second tooth bottom portion 22b is the second drawing point as shown in FIG. Is formed by a second curve obtained by rolling the inversion circle Ci inscribed in the base circle BCt without slipping while changing the radius (see the two-dot chain line in the figure). For the procedure for changing the radius of the first or second drawing point of the abduction circle Co or the inversion circle Ci, refer to Japanese Patent Application Laid-Open No. 2014-181619.
　ここで、第１および第２吐出ポート７，８を有するギヤポンプ１では、第１および第２吐出ポート７，８間での作動油の流通を規制して容積効率を向上させるために、当該ギヤポンプ１の軸方向からみて隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値をできるだけ小さくする必要がある。これに対して、吸入ポート６に連通する歯間室５に関しては、当該吸入ポート６からの作動油の流入（吸入）に伴うキャビテーションの発生を抑制する観点から、外歯２０と内歯３０とのクリアランスの最小値を大きくして互いに隣り合う歯間室５間の作動油の流通を許容し、それにより吸入ポート６から流入する作動油の流速を低下させる必要がある。そこで、本発明者らは、第１および第２吐出ポート７，８間における外歯２０と内歯３０とのクリアランスの最小値や、吸入ポート６側における外歯２０と内歯３０とのクリアランスの最小値の適正化を図るべく鋭意研究を行った。その結果、本発明者らは、インナーロータ２が単位角度だけ回転する際の吸入ポート６に連通する歯間室５の容積Ｖの変化量（単位角度あたりの容積変化量、以下、「容積変化率ΔＶ」という）に着目するに至った。 Here, in the gear pump 1 having the first and second discharge ports 7 and 8, in order to improve the volumetric efficiency by regulating the flow of the hydraulic oil between the first and second discharge ports 7 and 8, the gear pump 1 It is necessary to make the minimum value of the clearance between the external teeth 20 and the internal teeth 30 overlapping with the partition wall 9 as small as possible when viewed from the axial direction of 1. On the other hand, with respect to the interdental chamber 5 communicating with the suction port 6, from the viewpoint of suppressing the occurrence of cavitation associated with the inflow (suction) of hydraulic oil from the suction port 6, the external teeth 20 and the internal teeth 30 It is necessary to increase the minimum value of the clearance to allow the hydraulic oil to flow between the interdental chambers 5 adjacent to each other, thereby reducing the flow velocity of the hydraulic oil flowing from the suction port 6. Therefore, the inventors have determined the minimum clearance between the external teeth 20 and the internal teeth 30 between the first and second discharge ports 7 and 8 and the clearance between the external teeth 20 and the internal teeth 30 on the suction port 6 side. We conducted intensive research to optimize the minimum value. As a result, the present inventors have found that the amount of change in the volume V of the interdental chamber 5 communicating with the suction port 6 when the inner rotor 2 rotates by a unit angle (volume change amount per unit angle, hereinafter referred to as “volume change”). It has come to focus on "rate ΔV").
　すなわち、吸入ポート６に連通すると共に容積変化率ΔＶが最大となる歯間室５では、容積変化率ΔＶが最大となる際に内圧が大きく低下し、内圧の低下に起因して吸入ポート６から高い流速で作動油が流入することによりキャビテーションが発生しやすくなってしまう。そして、吸入ポート６に連通すると共に容積変化率ΔＶが最大となる歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値（以下、適宜「吸入側クリアランス」という）が小さいほど、当該歯間室５内の圧力の低下量（負圧）は、容積変化率ΔＶが最大になる際に大きくなる。 That is, in the interdental chamber 5 that communicates with the suction port 6 and has the maximum volume change rate ΔV, the internal pressure greatly decreases when the volume change rate ΔV becomes the maximum, and from the suction port 6 due to the decrease in the internal pressure. Cavitation tends to occur when hydraulic fluid flows at a high flow rate. The minimum value of the clearance between the external teeth 20 and the internal teeth 30 that define the interdental chamber 5 that communicates with the intake port 6 and has the maximum volume change rate ΔV (hereinafter referred to as “intake side clearance” as appropriate). The smaller the amount, the lower the amount of pressure in the interdental chamber 5 (negative pressure) becomes larger when the volume change rate ΔV becomes maximum.
　これを踏まえて、インナーロータ２の複数の外歯２０は、理想中心状態で、容積変化率ΔＶ量が最大になる際に隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値（以下、適宜「吐出側クリアランス」という）よりも上記吸入側クリアランスが大きくなるように、それぞれ歯形中心線Ｌｃに関して非対称に形成される。“理想中心状態”は、インナーロータ２の回転中心ｃと当該インナーロータ２に固定された回転軸４の回転中心とが一致すると共に、アウターロータ３の回転中心ｃと当該アウターロータ３が収容されるギヤ収容室の中心とが一致する状態をいう。 Based on this, the plurality of external teeth 20 of the inner rotor 2 are in the ideal center state, and the minimum clearance (the clearance between the external teeth 20 and the internal teeth 30 that overlap the partition wall 9 when the volume change rate ΔV amount becomes maximum ( In the following description, the suction side clearance is appropriately asymmetrical with respect to the tooth profile center line Lc so as to be larger than the “discharge side clearance”. In the “ideal center state”, the rotation center c of the inner rotor 2 coincides with the rotation center of the rotation shaft 4 fixed to the inner rotor 2, and the rotation center c of the outer rotor 3 and the outer rotor 3 are accommodated. The state where the center of the gear housing chamber matches.
　上記吸入側クリアランスを吐出側クリアランスよりも大きくするために、第１中間部２３を形成する曲線の長さ、すなわち歯先部２１の端部２１ｆから第１歯底部２２ａの端部２２ｒまでの長さは、第２中間部２４を形成する曲線の長さ、すなわち歯先部２１の端部２１ｒから第２歯底部２２ｂの端部２２ｆまでの長さよりも長く定められる。更に、第１歯底部２２ａを形成するハイポトロコイド曲線の長さ、すなわち第１歯底部２２ａの端部２２ｒから交差部２２ｘまでの長さは、第２歯底部２２ｂを形成するハイポトロコイド曲線の長さ、すなわち第２歯底部２２ｂの端部２２ｆから交差部２２ｘまでの長さよりも短く定められる。このように、第１中間部２３を形成する曲線の長さを第２中間部２４を形成する曲線の長さよりも長くし、更に第１歯底部２２ａを形成するハイポトロコイド曲線の長さを第２歯底部２２ｂを形成するハイポトロコイド曲線の長さよりも短くすることで、図３に示すように、歯先部２１を形成するエピトロコイド曲線の回転方向後側の端部２１ｒを第２歯底部２２ｂにより近接させると共に、当該エピトロコイド曲線の回転方向前側の端部２１ｆをインナーロータ２の径方向における外側に寄せることができる。 In order to make the suction side clearance larger than the discharge side clearance, the length of the curve forming the first intermediate portion 23, that is, the length from the end portion 21f of the tooth tip portion 21 to the end portion 22r of the first tooth bottom portion 22a. The length is determined to be longer than the length of the curve forming the second intermediate portion 24, that is, the length from the end portion 21r of the tooth tip portion 21 to the end portion 22f of the second tooth bottom portion 22b. Furthermore, the length of the hypotrochoid curve forming the first tooth bottom portion 22a, that is, the length from the end 22r of the first tooth bottom portion 22a to the intersecting portion 22x is the length of the hypotrochoid curve forming the second tooth bottom portion 22b. That is, it is determined to be shorter than the length from the end portion 22f of the second tooth bottom portion 22b to the intersecting portion 22x. Thus, the length of the curve forming the first intermediate portion 23 is made longer than the length of the curve forming the second intermediate portion 24, and the length of the hypotrochoid curve forming the first tooth bottom portion 22a is set to the first length. By making it shorter than the length of the hypotrochoid curve forming the two tooth bottom portions 22b, the end portion 21r on the rear side in the rotational direction of the epitrochoid curve forming the tooth tip portion 21 is made the second tooth bottom portion as shown in FIG. 22b, and the end portion 21f on the front side in the rotational direction of the epitrochoid curve can be moved outward in the radial direction of the inner rotor 2.
　そして、歯先部２１を形成するエピトロコイド曲線の回転方向後側の端部２１ｒを第２歯底部２２ｂにより近接させることで、第１および第２吐出ポート７，８に連通する歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値を全体に小さくすることができる。また、歯先部２１を形成するエピトロコイド曲線の回転方向前側の端部２１ｆをインナーロータ２の径方向における外側に寄せることで、吸入ポート６に連通する歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値を全体に大きくすることができる。この結果、第１および第２吐出ポート７，８を仕切る隔壁９の位置すなわち第１および第２吐出ポート７，８からの吐出流量の分配比を定める際の自由度を向上させつつ、隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値（吐出側クリアランス）をより小さくし、かつ容積変化量ΔＶが最大となる歯間室５におけるクリアランスの最小値（吸入側クリアランス）を十分に大きくして当該歯間室５でのキャビテーションの発生を良好に抑制することが可能となる。 And the interdental chamber 5 connected to the 1st and 2nd discharge ports 7 and 8 by making the end part 21r on the back side in the rotation direction of the epitrochoid curve forming the tooth tip part 21 closer to the second tooth bottom part 22b. The minimum value of the clearance between the outer teeth 20 and the inner teeth 30 that define the above can be reduced as a whole. The outer teeth defining the interdental chamber 5 communicating with the suction port 6 by bringing the end portion 21f on the front side in the rotational direction of the epitrochoid curve forming the tooth tip portion 21 to the outside in the radial direction of the inner rotor 2 The minimum clearance between the teeth 20 and the internal teeth 30 can be increased as a whole. As a result, it is possible to improve the degree of freedom in determining the position of the partition wall 9 that partitions the first and second discharge ports 7, 8, that is, the distribution ratio of the discharge flow rate from the first and second discharge ports 7, 8. The minimum clearance (discharge-side clearance) between the external teeth 20 and the internal teeth 30 that overlap with each other is made smaller, and the minimum clearance (suction-side clearance) in the interdental chamber 5 where the volume change ΔV is maximum is sufficient. Therefore, the occurrence of cavitation in the interdental chamber 5 can be satisfactorily suppressed.
　また、ギヤポンプ１では、インナーロータ２およびアウターロータ３が理想中心状態から偏心した状態で回転している際、上死点に達した歯間室５のインナーロータ２の回転方向における後側に位置する何れか１つの外歯２０が対応する内歯３０と接触している間に、当該何れか１つの外歯２０よりもインナーロータ２の回転方向における１つ後側に位置する外歯２０が対応する内歯３０と接触するように、インナーロータ２の複数の外歯２０が形成される。すなわち、上死点を経て外歯２０の歯先頂部２１ｔと内歯３０の歯先頂部とが一直線上で対向する位置（図７における吸入ポート６と第１吐出ポート７との間の位置参照）に最接近した何れか１つの外歯２０が対応する内歯３０と接触している間に、当該何れか１つの外歯３０よりもインナーロータ２の回転方向における１つ後側に位置する外歯２０が対応する内歯３０と接触することになる。かかる条件を満たすように歯先部２１、第１および第２歯底部２２ａ，２２ｂ、第１および第２中間部２３，２４の諸元を定めることにより、ギヤポンプ１の作動中におけるインナーロータ２およびアウターロータ３の挙動を安定化させて振動やノイズを低減化することが可能となる。なお、“上死点”は、インナーロータ２等の回転に伴って増加する歯間室５の容積が最大となる位置（図１における吸入ポート６と第１吐出ポート７との間の位置）をいう。また、“理想中心状態から偏心した状態”とは、インナーロータ２の回転中心ｃと回転軸４の回転中心とのズレ、およびアウターロータ３の回転中心ｃとギヤ収容室の中心とのズレの少なくとも何れか一方が発生した状態をいう。 In the gear pump 1, when the inner rotor 2 and the outer rotor 3 are rotated in an eccentric state from the ideal center state, the interdental chamber 5 that has reached the top dead center is positioned on the rear side in the rotation direction of the inner rotor 2. While any one external tooth 20 is in contact with the corresponding internal tooth 30, the external tooth 20 located on the one rear side in the rotation direction of the inner rotor 2 is located with respect to any one external tooth 20. A plurality of external teeth 20 of the inner rotor 2 are formed so as to contact the corresponding internal teeth 30. That is, the position where the tooth tip apex 21t of the external tooth 20 and the tooth top apex of the internal tooth 30 face each other in a straight line through the top dead center (refer to the position between the suction port 6 and the first discharge port 7 in FIG. 7). While one of the outer teeth 20 closest to () is in contact with the corresponding inner tooth 30, the outer teeth 30 are positioned one rear side in the rotational direction of the inner rotor 2 with respect to any one of the outer teeth 30. The external teeth 20 come into contact with the corresponding internal teeth 30. By defining the specifications of the tooth tip portion 21, the first and second tooth bottom portions 22 a and 22 b, and the first and second intermediate portions 23 and 24 so as to satisfy such conditions, the inner rotor 2 during operation of the gear pump 1 and It is possible to stabilize the behavior of the outer rotor 3 and reduce vibration and noise. The “top dead center” is a position where the volume of the interdental chamber 5 that increases with the rotation of the inner rotor 2 or the like is maximized (position between the suction port 6 and the first discharge port 7 in FIG. 1). Say. In addition, the “decentered state from the ideal center state” means a deviation between the rotation center c of the inner rotor 2 and the rotation center of the rotation shaft 4 and a deviation between the rotation center c of the outer rotor 3 and the center of the gear housing chamber. A state in which at least one of them has occurred.
　図５に、ギヤポンプ１におけるインナーロータ２の回転中心２ｃ周りの回転角度θと、外歯２０および内歯３０のクリアランスの最小値との関係を例示し、図６に、インナーロータ２の回転中心２ｃ周りの回転角度θと、１つの歯間室５の容積Ｖおよび容積変化率ΔＶとの関係を例示する。 FIG. 5 illustrates the relationship between the rotation angle θ around the rotation center 2 c of the inner rotor 2 in the gear pump 1 and the minimum value of the clearance between the outer teeth 20 and the inner teeth 30, and FIG. 6 illustrates the rotation center of the inner rotor 2. The relationship between the rotation angle θ around 2c and the volume V and volume change rate ΔV of one interdental chamber 5 is illustrated.
　図５および図６は、インナーロータ２の歯底円の直径を例えば２０～８０ｍｍの範囲、アウターロータの歯底円の直径を例えば２５～１１０ｍｍの範囲、偏心量ｅを例えば１．０５～５．００ｍｍの範囲、Ｒｄｅ＝Ｒｄｈ＝Ｒｄを例えば０．５５～３．００ｍｍの範囲、ｒｅ＝ｒｈ＝Ｒを例えば０．５～２．０ｍｍの範囲内からそれぞれ選択したギヤポンプ１についての解析結果を示すものである。外歯２０と内歯３０とのクリアランスの最小値は、理想中心状態で、図７に示すように互いに最近接した外歯２０と内歯３０との歯面に対する法線の方向において測定される間隔である。また、インナーロータ２の回転中心２ｃ周りの回転角度θは、ある外歯２０の歯底部２２の最底部（最深部）と回転中心２ｃとを結ぶ線部の回転中心２ｃ周りの回転角度であり、インナーロータ２の回転中心２ｃの図中真下に当該外歯２０の歯底部２２の最底部が位置する状態を０°として図７中反時計周りに測定される。更に、図５における範囲Ａは、上記外歯２０の歯底部２２の最底部が隔壁９と重なる範囲を示す。また、図６に示す容積Ｖは、回転角度θの測定対象である歯底部２２を挟んで隣り合う２つの外歯２０と、それらに対応した２つの内歯３０とにより画成される歯間室５の容積である。更に、図６に示す容積変化率ΔＶは、回転角度θが例えば５°だけ変化（増加）する際の容積Ｖの変化量である。 5 and 6 show that the diameter of the root circle of the inner rotor 2 is in the range of, for example, 20 to 80 mm, the diameter of the root circle of the outer rotor is in the range of, for example, 25 to 110 mm, and the eccentricity e is, for example, 1.05 to 5 The analysis results for the gear pump 1 in which the range of .00 mm, Rde = Rdh = Rd, for example, 0.55 to 3.00 mm, and re = rh = R, for example, 0.5 to 2.0 mm are selected. It is shown. The minimum value of the clearance between the external teeth 20 and the internal teeth 30 is measured in the direction of the normal to the tooth surfaces of the external teeth 20 and the internal teeth 30 that are closest to each other as shown in FIG. It is an interval. Further, the rotation angle θ around the rotation center 2c of the inner rotor 2 is a rotation angle around the rotation center 2c of the line portion connecting the bottommost portion (deepest portion) of the tooth bottom portion 22 of the external tooth 20 and the rotation center 2c. 7 is measured counterclockwise in FIG. 7 when the state where the bottom of the bottom 22 of the external tooth 20 is located directly below the center of rotation 2c of the inner rotor 2 is 0 °. Further, a range A in FIG. 5 indicates a range in which the bottom part of the bottom part 22 of the external tooth 20 overlaps the partition wall 9. Further, the volume V shown in FIG. 6 is an interdental space defined by two external teeth 20 that are adjacent to each other with a tooth bottom portion 22 that is a measurement target of the rotation angle θ and two internal teeth 30 corresponding thereto. The volume of the chamber 5. Furthermore, the volume change rate ΔV shown in FIG. 6 is a change amount of the volume V when the rotation angle θ changes (increases) by, for example, 5 °.
　図５に示す解析結果より、ギヤポンプ１では、第１および第２吐出ポート７，８に連通する歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値を全体に小さくし、かつ吸入ポート６に連通する歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値を全体に大きくし得ることが理解されよう。また、上述のような諸元のギヤポンプ１では、図６に示すように、インナーロータ２の回転角度θが９０°から９５°に変化する際に図７に示す歯間室５ｍの容積変化率ΔＶが最大となり、歯間室５ｍを画成する外歯２０および３０のクリアランスＣＬｉおよびＣＬｉ′のうち小さい方、すなわち図７に示す外歯２０ｉと内歯３０ｉとのクリアランスの最小値ＣＬｉが上記吸入側クリアランスとなる。更に、歯間室５ｍの容積変化率ΔＶが最大になる際、隔壁９と重なり合う外歯２０ｄと内歯３０ｄとのクリアランスの最小値ＣＬｄが上記吐出側クリアランスとなる。そして、図５に示すように、外歯２０ｉと内歯３０ｉとのクリアランスの最小値ＣＬｉ（吸入側クリアランス）は、隔壁９と重なり合う外歯２０ｄと内歯３０ｄとのクリアランスの最小値ＣＬｄ（図５における範囲Ａ内の値）の９～１０倍程度の大きさとなる。かかる解析結果より、ギヤポンプ１では、隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値（吐出側クリアランス）をより小さくし、かつ容積変化量ΔＶが最大となる歯間室５におけるクリアランスの最小値（吸入側クリアランス）を十分に大きくして当該歯間室５でのキャビテーションの発生を良好に抑制し得ることが理解されよう。 From the analysis result shown in FIG. 5, in the gear pump 1, the minimum value of the clearance between the external teeth 20 and the internal teeth 30 that define the interdental chamber 5 that communicates with the first and second discharge ports 7 and 8 is reduced as a whole. In addition, it will be understood that the minimum clearance between the external teeth 20 and the internal teeth 30 defining the interdental chamber 5 communicating with the suction port 6 can be increased as a whole. Further, in the gear pump 1 having the above specifications, as shown in FIG. 6, when the rotational angle θ of the inner rotor 2 changes from 90 ° to 95 °, the volume change rate of the interdental chamber 5m shown in FIG. The smallest value CLi of the clearance between the external teeth 20i and the internal teeth 30i shown in FIG. 7 is the smaller of the clearances CLi and CLi ′ of the external teeth 20 and 30 that define the interdental chamber 5m. The suction side clearance. Further, when the volume change rate ΔV of the interdental chamber 5m is maximized, the minimum clearance CLd between the external teeth 20d and the internal teeth 30d overlapping the partition wall 9 is the discharge side clearance. As shown in FIG. 5, the minimum clearance CLi (suction side clearance) between the external teeth 20i and the internal teeth 30i is the minimum clearance CLd between the external teeth 20d and the internal teeth 30d overlapping the partition wall 9 (FIG. 5). 5 to 9 to 10 times as large as the value in the range A). From this analysis result, in the gear pump 1, in the interdental chamber 5 where the minimum clearance (discharge-side clearance) between the external teeth 20 and the internal teeth 30 overlapping the partition wall 9 is made smaller and the volume change ΔV is maximum. It will be understood that the minimum value of the clearance (suction side clearance) can be sufficiently increased to satisfactorily suppress the occurrence of cavitation in the interdental chamber 5.
　なお、図５に示すクリアランスの最小値は、理想中心状態での設計値（解析値）であり、製品としてのギヤポンプ１における外歯２０と内歯３０とのクリアランスの最小値は、製造公差等により変動する。この点に関し、本発明者らの実験・解析によれば、製品における上記吸入側クリアランス（ＣＬｉ）が吐出側クリアランス（ＣＬｄ）の少なくとも３倍以上になっていれば、隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値を実用上十分に小さくしつつ、容積変化率ΔＶが最大となる歯間室５におけるクリアランスの最小値を実用上十分な大きさにし得ることが確認されている。そして、ギヤポンプ１は、上死点に最接近した何れか１つの外歯２０が対応する内歯３０と接触している間に、当該何れか１つの外歯２０の回転方向における１つ後側に位置する外歯２０が対応する内歯３０と接触するように構成されるが、かかる条件を満たすようにインナーロータ２の複数の外歯２０を設計することで、上記吸入側クリアランス（ＣＬｉ）の上限が定まることになる。 The minimum clearance shown in FIG. 5 is a design value (analysis value) in an ideal center state, and the minimum clearance between the external teeth 20 and the internal teeth 30 in the gear pump 1 as a product is a manufacturing tolerance or the like. Varies depending on In this regard, according to experiments and analysis by the present inventors, if the suction side clearance (CLi) in the product is at least three times or more than the discharge side clearance (CLd), the external teeth 20 overlapping the partition wall 9 are obtained. It has been confirmed that the minimum value of the clearance in the interdental chamber 5 where the volume change rate ΔV is maximized can be made sufficiently large in practice, while the minimum value of the clearance between the teeth 30 and the internal teeth 30 is sufficiently small in practice. Yes. Then, while any one of the external teeth 20 closest to the top dead center is in contact with the corresponding internal tooth 30, the gear pump 1 is one rear side in the rotational direction of any one of the external teeth 20. The external teeth 20 positioned in the inner rotor 2 are configured to come into contact with the corresponding internal teeth 30. By designing the plurality of external teeth 20 of the inner rotor 2 so as to satisfy such conditions, the suction side clearance (CLi) is set. The upper limit of will be determined.
　また、ギヤポンプ１では、図７に示す歯間室５ｍの容積変化率ΔＶが最大になる際に１組の外歯２０ｄおよび内歯３０ｄが隔壁９と重なることから、当該外歯２０ｄと内歯３０ｄとのクリアランスの最小値ＣＬｄが上記吐出側クリアランスとされるが、必ずしもこれに限られるものではない。すなわち、ギヤポンプ１は、歯間室５ｍの容積変化率ΔＶが最大になる際に２組の外歯２０および内歯３０が隔壁９と重なり合うように構成されてもよく、この場合には、２組の外歯２０および内歯３０のクリアランスの最小値のうち、小さい方が上記吐出側クリアランスとされればよい。つまり、吐出側クリアランスは、容積変化率ΔＶが最大となる際に第１および第２吐出ポート７，８の間で隔壁と少なくとも部分的に重なり合う歯間室５を画成する外歯２０と内歯３０とのクリアランスの最小値とされてもよい。 Further, in the gear pump 1, when the volume change rate ΔV of the interdental chamber 5m shown in FIG. 7 is maximized, the pair of external teeth 20d and internal teeth 30d overlap with the partition wall 9. Therefore, the external teeth 20d and internal teeth The minimum clearance CLd with respect to 30d is set as the discharge-side clearance, but is not necessarily limited thereto. That is, the gear pump 1 may be configured such that the two sets of external teeth 20 and internal teeth 30 overlap the partition wall 9 when the volume change rate ΔV of the interdental chamber 5m is maximized. Of the minimum clearances of the outer teeth 20 and the inner teeth 30 in the set, the smaller one may be used as the discharge side clearance. In other words, the discharge-side clearance is defined by the external teeth 20 and the internal teeth that define the interdental chamber 5 that at least partially overlaps the partition wall between the first and second discharge ports 7 and 8 when the volume change rate ΔV becomes maximum. The minimum clearance with the teeth 30 may be set.
　更に、インナーロータ２およびアウターロータ３が理想中心状態から偏心した状態で回転している際、上死点に最接近した何れか１つの外歯２０が対応する内歯３０と接触している間に、当該何れか１つの外歯２０よりも回転方向における１つ後側に位置する外歯２０を対応する内歯３０に接触させるためには、理想回転状態での上死点における外歯３０と内歯２０とのチップクリアランスＣＬｘ（図７参照）を、上死点上の外歯３０よりも回転方向における１つ後側に位置する外歯３０の駆動歯面とそれに対応した内歯３０の被駆動歯面とのクリアランスの理想中心状態での最小値ＣＬｙ（図７参照）以上にするとよい。また、理想中心状態での上死点における外歯３０と内歯２０とのチップクリアランスＣＬｘは、２００μｍ以下にするとよい。これにより、吐出側クリアランスが大きくなってしまうのを抑制し、第１吐出ポート７から第２吐出ポート８への作動油の漏出を規制して容積効率を向上させることが可能となる。なお、理想中心状態でのチップクリアランスＣＬｘの下限値は、製造公差を考慮して、５μｍ以上とすればよい。 Furthermore, when the inner rotor 2 and the outer rotor 3 are rotating in an eccentric state from the ideal center state, any one of the external teeth 20 closest to the top dead center is in contact with the corresponding internal tooth 30. In addition, in order to bring the external tooth 20 positioned one rear side in the rotational direction from any one of the external teeth 20 into contact with the corresponding internal tooth 30, the external tooth 30 at the top dead center in the ideal rotation state. The tip clearance CLx (see FIG. 7) between the outer teeth 30 and the inner teeth 20 is set to the driving tooth surface of the outer teeth 30 located one rear side in the rotational direction with respect to the outer teeth 30 on the top dead center and the corresponding inner teeth 30. It is preferable that the clearance with the driven tooth surface be equal to or greater than the minimum value CLy (see FIG. 7) in the ideal center state. Further, the tip clearance CLx between the outer teeth 30 and the inner teeth 20 at the top dead center in the ideal center state is preferably set to 200 μm or less. As a result, the discharge-side clearance is prevented from becoming large, and the leakage of hydraulic oil from the first discharge port 7 to the second discharge port 8 can be restricted to improve the volumetric efficiency. The lower limit value of the tip clearance CLx in the ideal center state may be set to 5 μm or more in consideration of manufacturing tolerances.
　上述のように、ギヤポンプ１では、吸入ポート６に連通する歯間室５の容積変化を考慮して、隔壁９と重なり合う外歯２０と内歯３０とのクリアランスの最小値を基に、容積変化率ΔＶが最大となる歯間室５におけるクリアランスの最小値が大きくなるようにインナーロータ２の各外歯２０が非対称化される。これにより、第１および第２吐出ポート７，８間での作動油の流通を規制して容積効率の向上を図りつつ、吸入ポート６に連通する歯間室５でのキャビテーションの発生を抑制することが可能となる。 As described above, in the gear pump 1, the volume change based on the minimum clearance between the external teeth 20 and the internal teeth 30 that overlap the partition wall 9 in consideration of the volume change of the interdental chamber 5 communicating with the suction port 6. Each external tooth 20 of the inner rotor 2 is asymmetrical so that the minimum value of the clearance in the interdental chamber 5 where the rate ΔV is maximum is increased. Thus, the flow of hydraulic oil between the first and second discharge ports 7 and 8 is restricted to improve the volumetric efficiency, and the occurrence of cavitation in the interdental chamber 5 communicating with the suction port 6 is suppressed. It becomes possible.
　また、ギヤポンプ１において、インナーロータ２の各外歯２０の歯先部２１は、トロコイド係数が値１よりも大きいエピトロコイド曲線のループ部以外の部分により形成され、歯底部２２は、当該エピトロコイド曲線と基礎円ＢＣｔを共通にすると共にトロコイド係数が値１よりも大きいハイポトロコイド曲線のループ以外の部分により形成される。これにより、外転円Ｃｏや内転円Ｃｉの半径ｒｅ，ｒｈ(∝基礎円ＢＣｔの半径／歯数)を小さく保ったまま第１および第２の描画点の半径ｒｄｅ，ｒｄｈすなわち第１および第２の値Ｒｄｅ，Ｒｄｈを大きくすることで、１つの基礎円ＢＣｔを用いて歯先部２１および歯底部２２の形状を定めると共に当該基礎円ＢＣｔの外径すなわちインナーロータ２の外径を小さく保ったまま歯丈を容易に高くすることが可能となる。 Further, in the gear pump 1, the tooth tip portion 21 of each external tooth 20 of the inner rotor 2 is formed by a portion other than the loop portion of the epitrochoid curve having a trochoid coefficient larger than 1, and the tooth bottom portion 22 is formed by the epitrochoid. The curve and the base circle BCt are made common and formed by a portion other than the hypotrochoid curve loop in which the trochoid coefficient is larger than 1. As a result, the radii rde, rdh of the first and second drawing points, that is, the first and second radii are maintained while keeping the radii re, rh (radius / number of teeth of the heel base circle BCt) of the abduction circle Co and the inversion circle Ci. By increasing the second values Rde and Rdh, the shape of the tooth tip portion 21 and the tooth bottom portion 22 is determined using one basic circle BCt, and the outer diameter of the basic circle BCt, that is, the outer diameter of the inner rotor 2 is reduced. It is possible to easily increase the tooth height while maintaining it.
　更に、ギヤポンプ１では、歯先部２１のインナーロータ２の回転方向における前側に位置する第１中間部２３がインボリュート曲線により形成される。これにより、インナーロータ２の外歯２０とアウターロータ３の内歯３０とをよりスムースに噛み合わせると共にインナーロータ２とアウターロータ３との回転速度比を一定にすることが可能となる。ただし、第１中間部２３は、例えばｎ次関数（ただし、“ｎ”は値１以上の整数である。）、円弧、任意の多項式、三角関数、緩和曲線、更にはこれらの組み合わせといったインボリュート曲線以外の曲線により形成されてもよいことはいうまでもない。 Furthermore, in the gear pump 1, the first intermediate portion 23 positioned on the front side of the tooth tip portion 21 in the rotation direction of the inner rotor 2 is formed by an involute curve. As a result, the outer teeth 20 of the inner rotor 2 and the inner teeth 30 of the outer rotor 3 can be meshed more smoothly and the rotational speed ratio between the inner rotor 2 and the outer rotor 3 can be made constant. However, the first intermediate unit 23 is an involute curve such as an n-order function (where “n” is an integer of 1 or more), an arc, an arbitrary polynomial, a trigonometric function, a relaxation curve, and a combination thereof. Needless to say, it may be formed by other curves.
　また、ギヤポンプ１では、第２中間部２４の基礎円ＢＣｔとの交差部２４ｘから歯先部２１の端部２１ｒまでの範囲が外転円Ｃｏの描画点の半径を変化させながら基礎円ＢＣｔに外接する当該外転円Ｃｏを滑りなく転動させて得られる第１の曲線により形成される。更に、第２中間部２４の基礎円ＢＣｔとの交差部２４ｘから第２歯底部２２ｂの端部２２ｆまでの範囲は、内転円Ｃｉの描画点の半径を変化させながら基礎円ＢＣｔに内接する当該内転円Ｃｉを滑りなく転動させて得られる第２の曲線により形成される。これにより、歯先部２１のインナーロータの回転方向における後側の端部２１ｒを第２歯底部２２ｂにできるだけ近接させつつ、歯先部２１と第２歯底部２２ｂとを滑らかに繋ぐ第２中間部２４を構成することが可能となる。ただし、第２中間部２４も、例えばｎ次関数（ただし、“ｎ”は値１以上の整数である。）、円弧、任意の多項式、三角関数、緩和曲線、更にはこれらの組み合わせといったインボリュート曲線以外の曲線により形成されてもよいことはいうまでもない。 Further, in the gear pump 1, the range from the intersection 24x with the basic circle BCt of the second intermediate portion 24 to the end 21r of the tooth tip 21 changes to the basic circle BCt while changing the radius of the drawing point of the abduction circle Co. It is formed by a first curve obtained by rolling the circumscribed circle Co that circumscribes it without slipping. Further, the range from the intersection 24x of the second intermediate portion 24 with the basic circle BCt to the end 22f of the second tooth bottom portion 22b is inscribed in the basic circle BCt while changing the radius of the drawing point of the inversion circle Ci. It is formed by a second curve obtained by rolling the inward circle Ci without slipping. Accordingly, the second intermediate portion smoothly connecting the tooth tip portion 21 and the second tooth bottom portion 22b while bringing the rear end portion 21r of the tooth tip portion 21 in the rotation direction of the inner rotor as close as possible to the second tooth bottom portion 22b. The part 24 can be configured. However, the second intermediate portion 24 is also an involute curve such as an n-order function (where “n” is an integer equal to or greater than 1), an arc, an arbitrary polynomial, a trigonometric function, a relaxation curve, and a combination thereof. Needless to say, it may be formed by other curves.
　以上説明したように、本開示のギヤポンプは、複数の外歯を有するインナーロータと、前記インナーロータの前記外歯よりも多い複数の内歯を有すると共に該インナーロータに対して偏心するように配置されるアウターロータと、隣り合う２つの前記外歯と隣り合う２つの前記内歯とにより画成される複数の歯間室とを含むギヤポンプにおいて、前記インナーロータおよび前記アウターロータの回転に伴って容積が増加する前記歯間室に連通する１つの吸入ポートと、隔壁により仕切られて互いに独立しており、それぞれ前記インナーロータおよび前記アウターロータの回転に伴って容積が減少する前記歯間室に連通する第１および第２吐出ポートとを備え、前記吸入ポートに連通すると共に前記インナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吸入側クリアランスとし、前記単位角度あたりの前記容積変化量が最大となる際に前記第１および第２吐出ポートの間で前記隔壁と少なくとも部分的に重なり合う歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吐出側クリアランスとしたときに、前記吸入側クリアランスが前記吐出側クリアランスよりも大きいことを特徴とする。 As described above, the gear pump according to the present disclosure has an inner rotor having a plurality of external teeth, a plurality of internal teeth that are larger than the external teeth of the inner rotor, and is arranged to be eccentric with respect to the inner rotor. And a plurality of interdental chambers defined by the two adjacent external teeth and the two adjacent internal teeth, with the rotation of the inner rotor and the outer rotor. One suction port that communicates with the interdental chamber that increases in volume, and the interdental chamber that is partitioned by a partition wall and independent from each other, and the volume decreases as the inner rotor and the outer rotor rotate. A first discharge port and a second discharge port communicating with each other, wherein the inner rotor rotates by a unit angle while communicating with the suction port; The minimum clearance between the external teeth and the internal teeth that defines the interdental chamber that maximizes the volume change amount is defined as the suction side clearance, and the volume change amount per unit angle is maximized when the volume change amount is maximized. The suction side clearance when the minimum clearance between the external teeth and the internal teeth that define an interdental chamber that at least partially overlaps the partition wall between the first and second discharge ports is the discharge side clearance. Is larger than the discharge-side clearance.
　このギヤポンプは、１つの吸入ポートと、隔壁により仕切られて互いに独立した第１および第２吐出ポートとを有するものである。このようなギヤポンプでは、第１および第２吐出ポートの間で隔壁と重なり合う外歯と内歯とのクリアランスの最小値をより小さくすることで、第１および第２吐出ポート間での流体の流通を規制して容積効率を向上させることができる。これに対して、吸入ポートに連通する歯間室に関しては、当該吸入ポートからの流体の流入（吸入）に伴うキャビテーションの発生を抑制する観点から、外歯と内歯とのクリアランスの最小値を大きくする必要がある。特に、吸入ポートに連通すると共にインナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室では、単位角度あたりの容積変化量が最大となる際に内圧が大きく低下し、内圧の低下に起因して吸入ポートから高い流速で流体が流入することによりキャビテーションが発生しやすくなってしまう。そして、吸入ポートに連通すると共にインナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する外歯と内歯とのクリアランスの最小値、すなわち吸入側クリアランスが小さいほど、当該歯間室内の圧力の低下量（負圧）は、単位角度あたりの容積変化量が最大になる際に大きくなる。これを踏まえて、このギヤポンプのインナーロータは、吸入側クリアランスが、単位角度あたりの容積変化量が最大となる際に隔壁と少なくとも部分的に重なり合う歯間室を画成する外歯と内歯とのクリアランスの最小値、すなわち吐出側クリアランスよりも大きくなるように形成される。このように、吸入ポートに連通する歯間室の容積変化を考慮して、隔壁と少なくとも部分的に重なり合う歯間室を画成する外歯と内歯とのクリアランスの最小値を基に、容積変化量が最大となる歯間室におけるクリアランスの最小値が大きくなるようにインナーロータを形成することで、第１および第２吐出ポート間での流体の流通を規制して容積効率の向上を図りつつ、吸入ポートに連通する歯間室でのキャビテーションの発生を抑制することが可能となる。 This gear pump has one suction port and first and second discharge ports that are partitioned by a partition wall and independent from each other. In such a gear pump, the flow of fluid between the first and second discharge ports is reduced by further reducing the minimum clearance between the external teeth and the internal teeth that overlap the partition between the first and second discharge ports. Can be controlled to improve volumetric efficiency. On the other hand, with regard to the interdental chamber communicating with the suction port, the minimum clearance between the external teeth and the internal teeth is reduced from the viewpoint of suppressing the occurrence of cavitation due to the inflow (suction) of fluid from the suction port. It needs to be bigger. In particular, in the interdental chamber that communicates with the suction port and has the maximum volume change when the inner rotor rotates by a unit angle, the internal pressure greatly decreases when the volume change per unit angle becomes maximum. Cavitation is likely to occur due to the flow of fluid from the suction port at a high flow rate due to the decrease in the pressure. The minimum clearance between the external teeth and the internal teeth that define the interdental space that maximizes the volume change amount when the inner rotor rotates by a unit angle while communicating with the suction port, that is, the suction side clearance is small. As the amount of decrease in the pressure in the interdental chamber (negative pressure) increases, the volume change amount per unit angle becomes maximum. Based on this, the inner rotor of this gear pump has an external tooth and an internal tooth that define an interdental space that at least partially overlaps the partition wall when the suction side clearance has a maximum volume change per unit angle. The clearance is formed to be larger than the minimum value, that is, the discharge-side clearance. Thus, taking into account the volume change of the interdental chamber communicating with the suction port, the volume is determined based on the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that at least partially overlaps the partition wall. By forming the inner rotor so that the minimum value of the clearance in the interdental chamber where the amount of change is maximum is increased, the flow of fluid between the first and second discharge ports is regulated to improve volumetric efficiency. However, it is possible to suppress the occurrence of cavitation in the interdental chamber communicating with the suction port.
　また、前記複数の外歯は、それぞれ歯形中心線に関して非対称に形成されてもよい。これにより、吸入側クリアランスを吐出側クリアランスよりも容易に大きくすることが可能となる。なお、歯形中心線は、歯先部の頂部とインナーロータの回転中心とを結ぶ直線であってもよい。 The plurality of external teeth may be formed asymmetrically with respect to the tooth profile center line. Thereby, the suction side clearance can be easily made larger than the discharge side clearance. The tooth profile center line may be a straight line connecting the top of the tooth tip and the rotation center of the inner rotor.
　更に、前記吸入側クリアランスは、前記吐出側クリアランスの少なくとも３倍以上であってもよい。このように、吸入側クリアランスが吐出側クリアランスの３倍以上となるように複数の外歯をそれぞれ歯形中心線に関して非対称に形成すれば、隔壁と重なり合う外歯と内歯とのクリアランスの最小値を実用上十分に小さくしつつ、容積変化量が最大となる歯間室におけるクリアランスの最小値を実用上十分に大きくすることができる。これにより、容積効率をより向上させつつ、吸入ポートに連通する歯間室でのキャビテーションの発生を良好に抑制することが可能となる。 Furthermore, the suction side clearance may be at least three times the discharge side clearance. Thus, if the external teeth are formed asymmetrically with respect to the tooth profile center line so that the suction side clearance is three times or more of the discharge side clearance, the minimum clearance between the external teeth and the internal teeth overlapping the partition wall can be reduced. The minimum value of the clearance in the interdental chamber where the volume change amount is maximized can be made sufficiently large in practice while being sufficiently small in practice. Thereby, it becomes possible to satisfactorily suppress the occurrence of cavitation in the interdental chamber communicating with the suction port while further improving the volumetric efficiency.
　また、前記インナーロータおよび前記アウターロータが回転している際、前記外歯の歯先頂部と前記内歯の歯先頂部とが一直線上で対向する位置に最接近した何れか１つの前記外歯が対応する前記内歯と接触している間に、該何れか１つの前記外歯よりも前記インナーロータの回転方向における１つ後側に位置する前記外歯が対応する前記内歯と接触してもよい。これにより、ギヤポンプの作動中におけるインナーロータおよびアウターロータの挙動を安定化させて振動やノイズを低減化することが可能となる。 Further, when the inner rotor and the outer rotor are rotating, any one of the external teeth closest to a position where the tooth tops of the external teeth and the tooth tops of the internal teeth face each other on a straight line While one of the external teeth is in contact with the corresponding internal tooth, the external tooth positioned one rearward in the rotational direction of the inner rotor is in contact with the corresponding internal tooth. May be. As a result, it is possible to stabilize the behavior of the inner rotor and the outer rotor during operation of the gear pump and reduce vibration and noise.
　更に、何れか１つの前記外歯およびそれに対応した前記内歯の歯先頂部が一直線上に位置する際の前記外歯と前記内歯とのチップクリアランスは、前記何れか１つの前記外歯よりも前記インナーロータの回転方向における１つ後側に位置する前記外歯の駆動歯面とそれに対応した前記内歯の被駆動歯面とのクリアランスの最小値以上であってもよい。これにより、インナーロータおよびアウターロータが回転する際、外歯の歯先頂部と内歯の歯先頂部とが一直線上で対向する位置に最接近した何れか１つの外歯が対応する内歯と接触している間に、当該何れか１つの外歯よりも回転方向における１つ後側に位置する外歯を対応する内歯に接触させることが可能となる。 Furthermore, the tip clearance between the external teeth and the internal teeth when any one of the external teeth and the corresponding tooth tops of the internal teeth are positioned in a straight line is greater than that of any one of the external teeth. Alternatively, the clearance may be equal to or greater than the minimum value of the clearance between the driving tooth surface of the external tooth positioned on the rear side in the rotation direction of the inner rotor and the driven tooth surface of the internal tooth corresponding thereto. As a result, when the inner rotor and the outer rotor rotate, any one of the outer teeth closest to the position where the tooth tops of the external teeth and the tooth tops of the internal teeth face each other in a straight line corresponds to the corresponding internal teeth. While in contact, it is possible to bring the external tooth located one more rear side in the rotational direction than any one of the external teeth into contact with the corresponding internal tooth.
　また、前記何れか１つの前記外歯と、それに対応した前記内歯との前記チップクリアランスは、２００μｍ以下であってもよい。これにより、吐出側クリアランスが大きくなってしまうのを抑制し、第１および第２吐出ポート間での流体の流通を規制して容積効率を向上させることが可能となる。 Further, the tip clearance between any one of the outer teeth and the corresponding inner teeth may be 200 μm or less. Thereby, it is possible to suppress the increase in the discharge-side clearance and to regulate the fluid flow between the first and second discharge ports and to improve the volume efficiency.
　更に、前記インナーロータの前記外歯のそれぞれは、描画点の半径よりも小さい半径を有する外転円を基礎円に外接させながら滑りなく転動させて得られるエピトロコイド曲線により形成された歯先部と、描画点の半径よりも小さい半径を有する内転円を前記エピトロコイド曲線と共通の前記基礎円に内接させながら滑りなく転動させて得られるハイポトロコイド曲線により形成されると共に、前記歯先部よりも前記インナーロータの回転方向における前側に位置する第１歯底部と、前記内転円を前記基礎円に内接させながら滑りなく転動させて得られるハイポトロコイド曲線により形成されると共に、前記回転方向における後側の前記第１歯底部に連続する第２歯底部と、任意の曲線により形成されると共に、前記歯先部と前記第１歯底部との間に位置する第１中間部と、任意の曲線により形成されると共に、前記歯先部と前記第２歯底部との間に位置する第２中間部とを含んでもよく、前記第１中間部を形成する曲線の長さは、前記第２中間部を形成する曲線の長さよりも長くてもよい。 Further, each of the outer teeth of the inner rotor is a tooth tip formed by an epitrochoid curve obtained by rolling an outer rotation circle having a radius smaller than the drawing point radius without slipping while circumscribing the base circle. And a hypotrochoid curve obtained by rolling an inversion circle having a radius smaller than the radius of the drawing point without slipping while inscribed in the basic circle common to the epitrochoid curve, and A first tooth bottom portion located on the front side in the rotation direction of the inner rotor with respect to the tooth tip portion, and a hypotrochoid curve obtained by rolling the inner rotation circle without slipping while inscribed in the basic circle. And a second tooth bottom portion continuous with the first tooth bottom portion on the rear side in the rotation direction, and an arbitrary curve, and the tooth tip portion and the first tooth bottom. And a first intermediate portion located between the first tip portion and the second root portion, and a first intermediate portion located between the first tip portion and the second bottom portion. The length of the curve forming the intermediate portion may be longer than the length of the curve forming the second intermediate portion.
　このようにインナーロータの外歯を構成することにより、隔壁と重なり合う外歯と内歯とのクリアランスの最小値をより小さくしつつ、容積変化量が最大となる歯間室におけるクリアランスの最小値をより大きくすることが可能となる。すなわち、第１中間部を形成する曲線の長さを第２中間部を形成する曲線の長さよりも長くすることで、歯先部を形成するエピトロコイド曲線の回転方向後側の端部を第２歯底部により近接させると共に、当該エピトロコイド曲線の回転方向前側の端部をインナーロータの径方向における外側に寄せることができる。そして、歯先部を形成するエピトロコイド曲線の回転方向後側の端部を第２歯底部により近接させることで、第１および第２吐出ポートに連通する歯間室を画成する外歯と内歯とのクリアランスの最小値を全体に小さくすることができる。また、歯先部を形成するエピトロコイド曲線の回転方向前側の端部をインナーロータの径方向における外側に寄せることで、吸入ポートに連通する歯間室を画成する外歯と内歯とのクリアランスの最小値を全体に大きくすることができる。この結果、第１および第２吐出ポートを仕切る隔壁の位置すなわち第１および第２吐出ポートからの吐出流量の分配比を定める際の自由度を向上させつつ、隔壁と重なり合う外歯と内歯とのクリアランスの最小値をより小さくし、かつ容積変化量が最大となる歯間室におけるクリアランスの最小値を十分に大きくして当該歯間室でのキャビテーションの発生を良好に抑制することが可能となる。加えて、外転円や内転円の半径(∝基礎円の半径／歯数)を小さく保ったままエピトロコイド曲線やハイポトロコイド曲線の描画点半径を大きくすることで、１つの基礎円を用いて歯先部および歯底部の形状を定めると共に当該基礎円の外径すなわちインナーロータの外径を小さく保ったまま外歯の歯丈を容易に高くすることができる。 By configuring the outer teeth of the inner rotor in this way, the minimum value of the clearance between the external teeth and the internal teeth that overlap the partition wall is made smaller, while the minimum clearance value in the interdental chamber that maximizes the volume change amount is reduced. It becomes possible to make it larger. That is, by making the length of the curve forming the first intermediate portion longer than the length of the curve forming the second intermediate portion, the end portion on the rear side in the rotation direction of the epitrochoid curve forming the tooth tip portion is The two tooth bottoms can be brought closer to each other, and the end portion on the front side in the rotational direction of the epitrochoid curve can be moved outward in the radial direction of the inner rotor. Then, by bringing the end portion on the rear side in the rotation direction of the epitrochoid curve forming the tooth tip portion closer to the second tooth bottom portion, external teeth defining an interdental chamber communicating with the first and second discharge ports; The minimum value of clearance with the internal teeth can be reduced overall. In addition, by bringing the end portion of the epitrochoid curve forming the tooth tip portion on the front side in the rotational direction toward the outside in the radial direction of the inner rotor, the outer teeth and the inner teeth that define the interdental chamber communicating with the suction port The minimum clearance can be increased overall. As a result, while improving the degree of freedom in determining the position of the partition wall that partitions the first and second discharge ports, that is, the distribution ratio of the discharge flow rate from the first and second discharge ports, the external teeth and internal teeth that overlap the partition wall It is possible to reduce the cavitation in the interdental chamber satisfactorily by making the minimum clearance value smaller and sufficiently increasing the minimum clearance value in the interdental chamber where the volume change is maximum. Become. In addition, one basic circle is used by increasing the radius of the epitrochoid curve and hypotrochoid curve while keeping the radius of the abduction circle and adduction circle (the radius of the basic circle / the number of teeth) small. Thus, the shape of the tip portion and the bottom portion of the tooth can be determined, and the tooth height of the outer teeth can be easily increased while keeping the outer diameter of the basic circle, that is, the outer diameter of the inner rotor small.
　また、前記第１中間部は、少なくともインボリュート曲線により形成されてもよい。これにより、外歯と内歯とをよりスムースに噛み合わせると共にインナーロータとアウターロータとの回転速度比を一定にすることが可能となる。 Further, the first intermediate part may be formed by at least an involute curve. As a result, the external teeth and the internal teeth can be meshed more smoothly, and the rotational speed ratio between the inner rotor and the outer rotor can be made constant.
　更に、前記第２中間部の前記基礎円との交差部から前記歯先部との境界までの範囲は、前記外転円の前記描画点の半径を変化させながら前記基礎円に外接する該外転円を滑りなく転動させて得られる第１の曲線により形成されてもよく、前記第２中間部の前記基礎円との交差部から前記第２歯底部との境界までの範囲は、前記内転円の前記描画点の半径を変化させながら前記基礎円に内接する該内転円を滑りなく転動させて得られる第２の曲線により形成されてもよい。これにより、歯先部のインナーロータの回転方向における後側の端部を第２歯底部にできるだけ近接させつつ、歯先部と第２歯底部とを滑らかに繋ぐ第２中間部を構成することが可能となる。 Further, the range from the intersection of the second intermediate portion with the basic circle to the boundary with the tooth tip portion is the outer circumference circumscribing the basic circle while changing the radius of the drawing point of the abduction circle. It may be formed by a first curve obtained by rolling a rolling circle without slipping, and the range from the intersection of the second intermediate part with the basic circle to the boundary with the second tooth bottom is It may be formed by a second curve obtained by rolling the inversion circle inscribed in the basic circle without slipping while changing the radius of the drawing point of the inversion circle. Accordingly, the second intermediate portion that smoothly connects the tooth tip portion and the second tooth bottom portion while making the rear end portion of the tooth tip portion in the rotation direction of the inner rotor as close as possible to the second tooth bottom portion is configured. Is possible.
　また、前記複数の内歯により画成される前記アウターロータの歯形は、前記インナーロータの回転中心に対する前記アウターロータの回転中心の偏心量を“ｅ”とし、前記インナーロータの回転中心、前記アウターロータの回転中心、前記外歯の歯先部の頂部および前記内歯の歯先部の頂部が一直線上に位置する際の該外歯の歯先部と該内歯の歯先部とのクリアランスを“ｔ”としたときに、前記インナーロータの回転中心を前記アウターロータの回転中心を中心とする直径２・ｅ＋ｔの円周上で所定角度ずつ公転させると共に、前記インナーロータの回転中心が所定角度だけ公転する際にインナーロータを前記所定角度および前記インナーロータの歯数に応じた回転角度だけ自転させることにより得られる複数の歯形線に対して描かれる包絡線に基づいて定められてもよい。これにより、上述のようなインナーロータと適正に噛合可能なアウターロータを容易に得ることが可能となる。 Further, the tooth profile of the outer rotor defined by the plurality of inner teeth has an eccentricity amount of the rotation center of the outer rotor with respect to the rotation center of the inner rotor as “e”, and the rotation center of the inner rotor and the outer rotor Clearance between the tooth tip of the external tooth and the tooth tip of the internal tooth when the rotation center of the rotor, the top of the tooth tip of the external tooth and the top of the tooth tip of the internal tooth are positioned on a straight line Is set to “t”, the rotation center of the inner rotor is revolved by a predetermined angle on the circumference of the diameter 2 · e + t centering on the rotation center of the outer rotor, and the rotation center of the inner rotor is When revolving by an angle, the inner rotor is drawn with respect to a plurality of tooth profile lines obtained by rotating the inner rotor by the rotation angle corresponding to the predetermined angle and the number of teeth of the inner rotor. It may be determined based on 絡線. This makes it possible to easily obtain an outer rotor that can be properly meshed with the inner rotor as described above.
　本開示のギヤポンプの製造方法は、複数の外歯を有するインナーロータと、前記インナーロータの前記外歯よりも多い複数の内歯を有すると共に該インナーロータに対して偏心するように配置されるアウターロータと、隣り合う２つの前記外歯と隣り合う２つの前記内歯とにより画成される複数の歯間室と、前記インナーロータおよび前記アウターロータの回転に伴って容積が増加する前記歯間室に連通する１つの吸入ポートと、隔壁により仕切られて互いに独立しており、それぞれ前記インナーロータおよび前記アウターロータの回転に伴って容積が減少する前記歯間室に連通する第１および第２吐出ポートとを備えたギヤポンプの製造方法であって、前記吸入ポートに連通すると共に前記インナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吸入側クリアランスとし、前記単位角度あたりの前記容積変化量が最大となる際に前記第１および第２吐出ポートの間で前記隔壁と少なくとも部分的に重なり合う歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吐出側クリアランスとしたときに、前記吸入側クリアランスが前記吐出側クリアランスよりも大きくなるように、前記インナーロータを形成するステップを含むものである。 A manufacturing method of a gear pump according to the present disclosure includes an inner rotor having a plurality of external teeth, and an outer rotor having a plurality of inner teeth larger than the outer teeth of the inner rotor and arranged eccentric to the inner rotor. A plurality of interdental chambers defined by the rotor, the two adjacent external teeth and the two adjacent internal teeth, and the interdental space whose volume increases as the inner rotor and the outer rotor rotate. A suction port that communicates with the chamber, and a first and a second that are partitioned by a partition wall and are independent of each other, and communicate with the interdental chamber that decreases in volume as the inner rotor and the outer rotor rotate. A method for manufacturing a gear pump comprising a discharge port, wherein the inner rotor rotates at a unit angle while communicating with the suction port. The minimum clearance between the external teeth and the internal teeth that define the interdental chamber where the amount of change is the maximum is the suction side clearance, and the first change when the volume change amount per unit angle is the maximum. When the minimum clearance between the external teeth and the internal teeth defining the interdental chamber at least partially overlapping the partition wall between the second discharge ports is the discharge side clearance, the suction side clearance is A step of forming the inner rotor so as to be larger than the discharge-side clearance;
　この方法により製造されたギヤポンプでは、第１および第２吐出ポート間での流体の流通を規制して容積効率の向上を図りつつ、吸入ポートに連通する歯間室でのキャビテーションの発生を抑制することが可能となる。 In the gear pump manufactured by this method, the flow of fluid between the first and second discharge ports is restricted to improve the volumetric efficiency, and the occurrence of cavitation in the interdental chamber communicating with the suction port is suppressed. It becomes possible.
　そして、本開示の発明は上記実施形態に何ら限定されるものではなく、本開示の外延の範囲内において様々な変更をなし得ることはいうまでもない。更に、上記発明を実施するための形態は、あくまで発明の概要の欄に記載された発明の具体的な一形態に過ぎず、発明の概要の欄に記載された発明の要素を限定するものではない。 And the invention of this indication is not limited to the said embodiment at all, and it cannot be overemphasized that various changes can be made within the range of the extension of this indication. Furthermore, the mode for carrying out the invention described above is merely a specific form of the invention described in the Summary of Invention column, and does not limit the elements of the invention described in the Summary of Invention column. Absent.
　本開示の発明は、ギヤポンプの製造産業において利用可能である。 The invention of the present disclosure can be used in the gear pump manufacturing industry.

Claims (11)

  1. 　複数の外歯を有するインナーロータと、前記インナーロータの前記外歯よりも多い複数の内歯を有すると共に該インナーロータに対して偏心するように配置されるアウターロータと、隣り合う２つの前記外歯と隣り合う２つの前記内歯とにより画成される複数の歯間室とを含むギヤポンプにおいて、
    　前記インナーロータおよび前記アウターロータの回転に伴って容積が増加する前記歯間室に連通する１つの吸入ポートと、
    　隔壁により仕切られて互いに独立しており、それぞれ前記インナーロータおよび前記アウターロータの回転に伴って容積が減少する前記歯間室に連通する第１および第２吐出ポートとを備え、
    　前記吸入ポートに連通すると共に前記インナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吸入側クリアランスとし、前記単位角度あたりの前記容積変化量が最大となる際に前記第１および第２吐出ポートの間で前記隔壁と少なくとも部分的に重なり合う歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吐出側クリアランスとしたときに、前記吸入側クリアランスが前記吐出側クリアランスよりも大きいギヤポンプ。     An inner rotor having a plurality of outer teeth, an outer rotor having a plurality of inner teeth larger than the outer teeth of the inner rotor and arranged to be eccentric with respect to the inner rotor, and two adjacent outer In a gear pump including a plurality of interdental chambers defined by two internal teeth adjacent to a tooth,
    One suction port communicating with the interdental chamber, the volume of which increases with the rotation of the inner rotor and the outer rotor;
    First and second discharge ports that are partitioned by a partition wall and are independent of each other, each communicating with the interdental chamber, the volume of which decreases as the inner rotor and the outer rotor rotate.
    The suction side clearance is defined as the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that communicates with the suction port and that has a maximum volume change when the inner rotor rotates by a unit angle. The external teeth and the internal teeth defining an interdental chamber at least partially overlapping the partition wall between the first and second discharge ports when the volume change amount per unit angle is maximized. A gear pump in which the suction side clearance is larger than the discharge side clearance when the minimum clearance is the discharge side clearance.
  2. 　請求項１に記載のギヤポンプにおいて、前記複数の外歯は、それぞれ歯形中心線に関して非対称に形成されるギヤポンプ。 2. The gear pump according to claim 1, wherein each of the plurality of external teeth is formed asymmetrically with respect to a tooth center line.
  3. 　請求項１または２に記載のギヤポンプにおいて、
    　前記吸入側クリアランスは、前記吐出側クリアランスの少なくとも３倍以上であるギヤポンプ。     The gear pump according to claim 1 or 2,
    The gear pump, wherein the suction side clearance is at least three times the discharge side clearance.
  4. 　請求項１から３の何れか一項に記載のギヤポンプにおいて、
    　前記インナーロータおよび前記アウターロータが回転している際、前記外歯の歯先頂部と前記内歯の歯先頂部とが一直線上で対向する位置に最接近した何れか１つの前記外歯が対応する前記内歯と接触している間に、該何れか１つの前記外歯よりも前記インナーロータの回転方向における１つ後側に位置する前記外歯が対応する前記内歯と接触するギヤポンプ。     The gear pump according to any one of claims 1 to 3,
    When the inner rotor and the outer rotor are rotating, any one of the outer teeth closest to the position where the tooth tops of the external teeth and the tooth tops of the internal teeth face each other in a straight line corresponds. A gear pump in which the external tooth positioned one rear side in the rotation direction of the inner rotor comes into contact with the corresponding internal tooth while being in contact with the internal tooth.
  5. 　請求項１から４の何れか一項に記載のギヤポンプにおいて、
    　何れか１つの前記外歯およびそれに対応した前記内歯の歯先頂部が一直線上に位置する際の前記外歯と前記内歯とのチップクリアランスは、前記何れか１つの前記外歯よりも前記インナーロータの回転方向における１つ後側に位置する前記外歯の駆動歯面とそれに対応した前記内歯の被駆動歯面とのクリアランスの最小値以上であるギヤポンプ。     In the gear pump according to any one of claims 1 to 4,
    The tip clearance between the external teeth and the internal teeth when the tooth tops of the external teeth and the internal teeth corresponding to the external teeth are aligned in a straight line is more than that of the external teeth. A gear pump that is equal to or greater than a minimum clearance between the drive tooth surface of the external tooth and the corresponding driven tooth surface of the internal tooth that are located on the rear side in the rotation direction of the inner rotor.
  6. 　請求項５に記載のギヤポンプにおいて、
    　前記何れか１つの前記外歯と、それに対応した前記内歯との前記チップクリアランスは、２００μｍ以下であるギヤポンプ。     The gear pump according to claim 5,
    A gear pump in which the tip clearance between any one of the outer teeth and the corresponding inner teeth is 200 μm or less.
  7. 　請求項１から６の何れか一項に記載のギヤポンプにおいて、
    　前記インナーロータの前記外歯のそれぞれは、
    　描画点の半径よりも小さい半径を有する外転円を基礎円に外接させながら滑りなく転動させて得られるエピトロコイド曲線により形成された歯先部と、
    　描画点の半径よりも小さい半径を有する内転円を前記エピトロコイド曲線と共通の前記基礎円に内接させながら滑りなく転動させて得られるハイポトロコイド曲線により形成されると共に、前記歯先部よりも前記インナーロータの回転方向における前側に位置する第１歯底部と、
    　前記内転円を前記基礎円に内接させながら滑りなく転動させて得られるハイポトロコイド曲線により形成されると共に、前記回転方向における後側の前記第１歯底部に連続する第２歯底部と、
    　任意の曲線により形成されると共に、前記歯先部と前記第１歯底部との間に位置する第１中間部と、
    　任意の曲線により形成されると共に、前記歯先部と前記第２歯底部との間に位置する第２中間部とを含み、
    　前記第１中間部を形成する曲線の長さは、前記第２中間部を形成する曲線の長さよりも長いギヤポンプ。     The gear pump according to any one of claims 1 to 6,
    Each of the outer teeth of the inner rotor is
    A tooth tip formed by an epitrochoid curve obtained by rolling without rolling while an outer circle having a radius smaller than the radius of the drawing point is circumscribed to the base circle;
    The addendum circle having a radius smaller than the radius of the drawing point is formed by a hypotrochoid curve obtained by rolling without slipping while inscribed in the basic circle common to the epitrochoid curve, and the tooth tip portion Than the first tooth bottom portion located on the front side in the rotational direction of the inner rotor,
    A second tooth bottom formed by a hypotrochoid curve obtained by rolling the inward circle with the base circle without slipping, and continuing to the first tooth bottom on the rear side in the rotation direction; ,
    A first intermediate part formed by an arbitrary curve and located between the tooth tip part and the first tooth bottom part;
    A second intermediate portion formed by an arbitrary curve and positioned between the tooth tip portion and the second tooth bottom portion;
    The length of the curve that forms the first intermediate portion is longer than the length of the curve that forms the second intermediate portion.
  8. 　請求項７に記載のギヤポンプにおいて、前記第１中間部は、少なくともインボリュート曲線により形成されるギヤポンプ。 8. The gear pump according to claim 7, wherein the first intermediate portion is formed by at least an involute curve.
  9. 　請求項７または８に記載のギヤポンプにおいて、
    　前記第２中間部の前記基礎円との交差部から前記歯先部との境界までの範囲は、前記外転円の前記描画点の半径を変化させながら前記基礎円に外接する該外転円を滑りなく転動させて得られる第１の曲線により形成されると共に、前記第２中間部の前記基礎円との交差部から前記第２歯底部との境界までの範囲は、前記内転円の前記描画点の半径を変化させながら前記基礎円に内接する該内転円を滑りなく転動させて得られる第２の曲線により形成されるギヤポンプ。     The gear pump according to claim 7 or 8,
    The range from the intersection of the second intermediate portion with the basic circle to the boundary with the tooth tip portion is the abduction circle circumscribing the basic circle while changing the radius of the drawing point of the abduction circle. Is formed by a first curve obtained by rolling without slipping, and the range from the intersection of the second intermediate portion with the base circle to the boundary with the second tooth bottom is the inward circle. A gear pump formed by a second curve obtained by rolling the inversion circle inscribed in the basic circle without slipping while changing the radius of the drawing point.
  10. 　請求項１から９の何れか一項に記載のギヤポンプにおいて、
    　前記複数の内歯により画成される前記アウターロータの歯形は、前記インナーロータの回転中心に対する前記アウターロータの回転中心の偏心量を“ｅ”とし、前記インナーロータの回転中心、前記アウターロータの回転中心、前記外歯の歯先部の頂部および前記内歯の歯先部の頂部が一直線上に位置する際の該外歯の歯先部と該内歯の歯先部とのクリアランスを“ｔ”としたときに、前記インナーロータの回転中心を前記アウターロータの回転中心を中心とする直径２・ｅ＋ｔの円周上で所定角度ずつ公転させると共に、前記インナーロータの回転中心が所定角度だけ公転する際にインナーロータを前記所定角度および前記インナーロータの歯数に応じた回転角度だけ自転させることにより得られる複数の歯形線に対して描かれる包絡線に基づいて定められるギヤポンプ。     The gear pump according to any one of claims 1 to 9,
    The tooth profile of the outer rotor defined by the plurality of internal teeth is “e” as the amount of eccentricity of the rotation center of the outer rotor with respect to the rotation center of the inner rotor, and the rotation center of the inner rotor and the outer rotor The clearance between the rotation tip, the top of the tooth tip of the external tooth, and the top of the tooth tip of the internal tooth is aligned with the tooth tip of the external tooth and the tooth tip of the internal tooth. t ″, the center of rotation of the inner rotor is revolved by a predetermined angle on the circumference of the diameter 2 · e + t centered on the center of rotation of the outer rotor, and the center of rotation of the inner rotor is rotated by a predetermined angle. When revolving, the envelope is drawn with respect to a plurality of tooth profile lines obtained by rotating the inner rotor by the predetermined angle and a rotation angle corresponding to the number of teeth of the inner rotor. Gear pump that is determined Zui.
  11. 　複数の外歯を有するインナーロータと、前記インナーロータの前記外歯よりも多い複数の内歯を有すると共に該インナーロータに対して偏心するように配置されるアウターロータと、隣り合う２つの前記外歯と隣り合う２つの前記内歯とにより画成される複数の歯間室と、前記インナーロータおよび前記アウターロータの回転に伴って容積が増加する前記歯間室に連通する１つの吸入ポートと、隔壁により仕切られて互いに独立しており、それぞれ前記インナーロータおよび前記アウターロータの回転に伴って容積が減少する前記歯間室に連通する第１および第２吐出ポートとを備えたギヤポンプの製造方法であって、
    　前記吸入ポートに連通すると共に前記インナーロータが単位角度だけ回転する際の容積変化量が最大となる歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吸入側クリアランスとし、前記単位角度あたりの前記容積変化量が最大となる際に前記第１および第２吐出ポートの間で前記隔壁と少なくとも部分的に重なり合う歯間室を画成する前記外歯と前記内歯とのクリアランスの最小値を吐出側クリアランスとしたときに、前記吸入側クリアランスが前記吐出側クリアランスよりも大きくなるように、前記インナーロータを形成するステップを含むギヤポンプの製造方法。     An inner rotor having a plurality of outer teeth, an outer rotor having a plurality of inner teeth larger than the outer teeth of the inner rotor and arranged to be eccentric with respect to the inner rotor, and two adjacent outer A plurality of interdental chambers defined by the two internal teeth adjacent to the teeth, and one suction port communicating with the interdental chambers that increase in volume as the inner rotor and the outer rotor rotate Manufacturing a gear pump including first and second discharge ports that are partitioned by a partition wall and are independent of each other, and each communicates with the interdental chamber that decreases in volume as the inner rotor and the outer rotor rotate. A method,
    The suction side clearance is defined as the minimum clearance between the external teeth and the internal teeth that define the interdental chamber that communicates with the suction port and that has a maximum volume change when the inner rotor rotates by a unit angle. The external teeth and the internal teeth defining an interdental chamber at least partially overlapping the partition wall between the first and second discharge ports when the volume change amount per unit angle is maximized. A method of manufacturing a gear pump including the step of forming the inner rotor so that the suction side clearance is larger than the discharge side clearance when the minimum clearance is the discharge side clearance.
PCT/JP2015/086533 2015-01-30 2015-12-28 Gear pump and method for manufacturing same WO2016121291A1 (en)

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CN112628137B (en) * 2020-11-20 2023-05-02 中国航发哈尔滨东安发动机有限公司 Cycloidal gear pump with high volumetric efficiency and method for improving volumetric efficiency
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KR102425555B1 (en) * 2021-03-31 2022-07-27 창원대학교 산학협력단 Rotor for rotary lobe pump

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