EP2642123A1 - Kühlstruktur für einen zylinderblock und hydraulische taumelscheibenvorrichtung damit - Google Patents

Kühlstruktur für einen zylinderblock und hydraulische taumelscheibenvorrichtung damit Download PDF

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Publication number
EP2642123A1
EP2642123A1 EP10859806.1A EP10859806A EP2642123A1 EP 2642123 A1 EP2642123 A1 EP 2642123A1 EP 10859806 A EP10859806 A EP 10859806A EP 2642123 A1 EP2642123 A1 EP 2642123A1
Authority
EP
European Patent Office
Prior art keywords
cylinder block
pressure
cooling
oil
cylinders
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP10859806.1A
Other languages
English (en)
French (fr)
Other versions
EP2642123A4 (de
Inventor
Takeshi Ohno
Makoto Azuma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kawasaki Heavy Industries Ltd
Kawasaki Motors Ltd
Original Assignee
Kawasaki Heavy Industries Ltd
Kawasaki Jukogyo KK
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 Kawasaki Heavy Industries Ltd, Kawasaki Jukogyo KK filed Critical Kawasaki Heavy Industries Ltd
Publication of EP2642123A1 publication Critical patent/EP2642123A1/de
Publication of EP2642123A4 publication Critical patent/EP2642123A4/de
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/06—Cooling; Heating; Prevention of freezing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
    • F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
    • F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F01B3/0032—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F01B3/0035—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/02—Cylinders; Cylinder heads  having cooling means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/26—Cylinder heads having cooling means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F04B1/22—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B25/00—Multi-stage pumps
    • F04B25/04—Multi-stage pumps having cylinders coaxial with, or parallel or inclined to, main shaft axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B39/00—Component parts, details, or accessories, of pumps or pumping systems specially adapted for elastic fluids, not otherwise provided for in, or of interest apart from, groups F04B25/00 - F04B37/00
    • F04B39/06—Cooling; Heating; Prevention of freezing
    • F04B39/066—Cooling by ventilation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/08—Cooling; Heating; Preventing freezing

Definitions

  • the present invention relates to a cooling structure of a cylinder block, such as a cylinder block of a swash plate type liquid-pressure apparatus, configured such that: a plurality of cylinders are formed on the cylinder block; pistons can be respectively inserted through openings of the cylinders, the openings being formed on a piston insertion end surface of the cylinder block; and the inserted pistons perform reciprocating sliding in the cylinders when the cylinder block is rotated.
  • swash plate type oil-pressure motor/pump (hereinafter may be referred to as a "swash plate type oil-pressure apparatus") as in PTL 1 is known.
  • the swash plate type oil-pressure apparatus of PTL 1 includes a rotating shaft, and a cylinder block is integrally attached to the rotating shaft. Cylinders are formed on an end surface of the cylinder block so as to be arranged at regular intervals in a circumferential direction, and pistons are respectively inserted into the cylinders. Shoes are respectively attached to end portions of the pistons, the end portions projecting from the cylinders. The shoes are arranged on a supporting surface of a swash plate provided to be inclined.
  • the cylinder block is rotated by the reciprocating movements of the pistons in the cylinders.
  • the pistons By supplying high-pressure operating oil to the cylinders, the pistons perform the reciprocating movements, and this rotates the cylinder block.
  • the rotating shaft formed integrally with the cylinder block is rotated by the rotation of the cylinder block.
  • the swash plate type oil-pressure apparatus serves as the oil-pressure motor.
  • the pistons by rotating the cylinder block, the pistons perform the reciprocating movements in the cylinders.
  • the swash plate type oil-pressure apparatus By rotating the cylinder block by the rotating shaft, the swash plate type oil-pressure apparatus can suction the low-pressure operating oil and eject the high-pressure operating oil.
  • the swash plate type oil-pressure apparatus can also serve as the oil-pressure pump.
  • the swash plate type oil-pressure apparatus configured as in PTL 1 has been mainly used in low-speed rotation and medium-speed rotation. However, it is desired that in order to respond to the increase in the rotation of a driving device of the construction machinery or the industrial machinery, the swash plate type oil-pressure apparatus is configured to be able to be used in high-speed rotation. However, if the cylinder block of the swash plate type oil-pressure apparatus is rotated at high speed, the influence of centrifugal force acting on the pistons and the shoes increases and becomes unignorable, unlike a case where the cylinder block of the swash plate type oil-pressure apparatus is rotated at low speed.
  • the pistons when the pistons perform the reciprocating movements in the cylinders, heat is generated by the sliding of the pistons on sliding surfaces of the cylinder block.
  • the amount of heat generated on the sliding surfaces depends on the contact pressure between the pistons and the cylinder block.
  • the contact pressure corresponds to the pressure of the operating oil supplied or ejected. Therefore, the heat generated on the sliding surfaces is comparatively small in amount.
  • the sliding surfaces can be adequately cooled only by the operating oil leaking from clearances each formed between the sliding surface and the piston for allowing the operating oil to escape.
  • the flow of the operating oil at the narrow radially outer clearances becomes nonsmooth, and the operating oil is heated at the narrow radially outer clearances. If the operating oil is continuously heated, and the temperature thereof exceeds a transition temperature of the operating oil, a lubrication performance of the operating oil decreases. With this, the amount of heat generated on the sliding surfaces further increases, and the cylinders and the pistons may be burned out. By increasing the widths of the clearances, the decrease in the lubrication performance of the operating oil and the burnout can be prevented. However, if the widths of the clearances are increased, the leakage amount of operating oil significantly increases. Therefore, the performance as the pump or motor deteriorates, and the increase in the pressure of the oil-pressure apparatus is limited.
  • an object of the present invention is to provide a cooling structure of a cylinder block capable of improving a cooling performance for sliding surfaces.
  • a cooling structure of a cylinder block according to the present invention is configured such that: a plurality of cylinders each including an opening on a piston insertion end surface of the cylinder block are formed on the cylinder block; and when the cylinder block is rotated, pistons respectively inserted in the cylinders perform reciprocating sliding, the cooling structure including: a plurality of cooling depressions formed on an outer peripheral surface of the cylinder block, wherein each of the cooling depressions extends from the piston insertion end surface on a dividing wall located between the two adjacent cylinders and is formed by reducing a thickness of the dividing wall so as to reduce a thickness of a portion between the outer peripheral surface of the cylinder block and a sliding surface on which the piston slides.
  • the thickness of the portion between the sliding surface and the outer peripheral surface becomes small. Since the temperature of the sliding surface in the vicinity of the outer periphery which generates heat by the centrifugal force generated by the high-speed rotation is higher than the temperature of drain oil in a case on the periphery of the sliding surface. Therefore, the heat generated on the sliding surfaces can be quickly transferred to the outer peripheral surface and thus can be released from the outer peripheral surface. With this, the cooling performance of the sliding surfaces can be improved, and the temperature increase of the sliding surfaces can be suppressed.
  • the cooling depressions extend from the piston insertion end surface on which the openings of the cylinders are located, the increase in the surface temperature of a portion of the sliding surface can be especially suppressed, the portion increasing in temperature most significantly and being located in the vicinity of the piston insertion end surface. Therefore, the occurrence of the burnout of the sliding surface can be suppressed.
  • a clearance is formed between the sliding surface and the outer peripheral surface of the piston, and the operating oil leaking from the clearance is utilized as lubricating oil.
  • the increase in the temperature of the lubricating oil can be suppressed, and the transition of the lubricating oil can be prevented.
  • smooth movements of the pistons can be maintained, and the amount of heat generated on the sliding surfaces can be reduced.
  • each of the pistons perform the reciprocating sliding between a top dead center and a bottom dead center in the cylinder; and each of the cooling depressions be formed so as to extend from the piston insertion end surface in parallel with the cylinder and be formed such that a tip end of the cooling depression is located on the piston insertion end surface side of a vicinity of an end surface of the piston located at the bottom dead center, the end surface being located in the cylinder.
  • each of the cooling depressions be formed so as to satisfy 0.02D ⁇ tmin ⁇ 0.3D, where tmin denotes a minimum thickness of the portion between the outer peripheral surface of the cylinder block and the sliding surface, and D denotes an inner diameter of the cylinder.
  • the stiffness of a region of the sliding surface can be secured while improving the cooling effect, the region being located on the outer peripheral surface side. With this, the burnout of the cylinder block and the damages on the opening side can be prevented.
  • a swash plate type liquid-pressure apparatus of the present invention is configured to be connected to a low-pressure passage through which a low-pressure operating liquid flows and a high-pressure passage through which a high-pressure operating oil flows and further configured such that: the cylinder block is rotated by supplying the operating liquid through the high-pressure passage to the cylinders and discharging the operating liquid from the cylinders to the low-pressure passage; or by rotating the cylinder block, the operating liquid is suctioned through the low-pressure passage to the cylinders, and the operating liquid is then compressed and ejected to the high-pressure passage, and the swash plate type liquid-pressure apparatus includes any one of the above cooling structures.
  • the clearance is formed between the sliding surface and the outer peripheral surface of the piston, and the operating oil leaking from the clearance is utilized as the lubricating oil.
  • the above configuration by suppressing the temperature increase of the sliding surface, the increase in the temperature of the lubricating oil leaking from the clearance can be suppressed, and the transition of the lubricating oil can be prevented. With this, the decrease in the lubrication performance of the lubricating oil can be prevented, the smooth movements of the pistons can be maintained, and the amount of heat generated on the sliding surfaces can be reduced.
  • the swash plate type liquid-pressure apparatus further include a casing configured to accommodate the cylinder block, wherein the casing is connected to the low-pressure passage through a communication passage, and low-pressure operating oil in the low-pressure passage is introduced to the casing.
  • the outer peripheral surface of the cylinder block can be subjected to low-pressure, low-temperature operating liquid introduced to the casing, the outer peripheral surface can be cooled by the operating liquid. With this, a larger amount of heat can be released from the outer peripheral surface, so that the increase in the surface temperature of the sliding surface can be further suppressed.
  • the cooling performance for the sliding surfaces can be improved.
  • a swash plate type liquid-pressure apparatus 1 according to an embodiment of the present invention will be explained in reference to the above drawings.
  • the swash plate type liquid-pressure apparatus 1 explained below is just one embodiment of the present invention.
  • the present invention is not limited to the embodiment, and additions, eliminations and modifications may be made within the spirit of the present invention.
  • the swash plate type liquid-pressure apparatus 1 is provided to drive respective devices and actuators included therein.
  • Examples of the construction machinery are oil-pressure shovels, cranes, and bulldozers.
  • Examples of the industrial machinery are land devices, such as oil-pressure units, pressing machines, ironmaking machines, and injection molding machines.
  • the swash plate type liquid-pressure apparatus 1 is a so-called swash plate type motor/pump and has the function of a liquid-pressure motor configured to cause a rotated object included in the industrial machinery or ship to rotate or the function of a liquid-pressure pump configured to supply a pressure liquid to an actuator included in the industrial machinery or ship to activate the actuator.
  • a fluid used is operating oil
  • the swash plate type liquid-pressure apparatus 1 will be explained as an oil-pressure motor.
  • an oil-pressure motor 1 that is the swash plate type liquid-pressure apparatus 1 is a high-speed rotation oil-pressure motor including a rotating shaft 11 and capable of rotating the rotating shaft 11 at high rotation speed.
  • the oil-pressure motor 1 further includes a cylinder block 12, a plurality of pistons 13, a plurality of shoes 14, a swash plate 15, and a valve plate 16, and these components are accommodated in a casing 17.
  • the rotating shaft 11 extends in a front-rear direction so as to penetrate the casing 17 and is rotatably supported by bearings 18 and 19 at front and rear end portions of the casing 17.
  • the cylinder block 12 is fitted on the rotating shaft 11 so as to be located on a rear end portion of a middle portion of the rotating shaft 11.
  • the cylinder block 12 is formed in a substantially cylindrical shape, and an axis thereof is located so as to coincide with an axis L1 of the rotating shaft 11.
  • the cylinder block 12 is integrally splined to the rotating shaft 11 and is not relatively rotatable with respect to the rotating shaft 11.
  • a front end portion of an outer peripheral surface 12a of the cylinder block 12 is reduced in thickness toward a radially inner side over the entire periphery in the circumferential direction, and a cooling structure 30 is formed on the front end portion of the outer peripheral surface 12a. Details of the configuration of the cooling structure 30 will be described below.
  • a plurality of cylinders 20 are formed on the cylinder block 12. As shown in Fig.
  • the cylinders 20 are arranged at regular intervals in the circumferential direction. As shown in Fig. 3 , the cylinders 20 extend in parallel with the axis L1. Each of the cylinders 20 is a hole defined by a sliding surface having a circular cross section and a bottom surface and has an opening on a front end surface (piston insertion end surface) of the cylinder block 12. The pistons 13 are respectively inserted through the openings to fit in the cylinders 20.
  • Each of the pistons 13 is formed in a substantially columnar shape and performs the reciprocating sliding in the front-rear direction while sliding on the sliding surface 12b defining the cylinder 20.
  • a cylindrical sleeve (not shown), such as a copper bushing, may fit in the cylinder 20.
  • the piston 13 slides on an inner peripheral surface of the sleeve, and the sliding surface on which the piston 13 slides denotes the inner peripheral surface of the sleeve.
  • the sleeve does not fit in the cylinder 20. However, the same is true for a case where the sleeve fits in the cylinder 20.
  • An outer diameter of the piston 13 is slightly smaller than an inner diameter of the cylinder 20, and a clearance is formed around the piston 13, that is, the clearance is formed between the piston 13 and the sliding surface 12b.
  • the piston 13 includes a spherical support portion 13a at its front end portion. The spherical support portion 13a projects from the cylinder 20 regardless of the position of the piston 13.
  • An outer surface of the spherical support portion 13a is formed in a substantially spherical shape, and the shoe 14 is attached to the spherical support portion 13a.
  • Each of the shoes 14 is formed in a substantially bottomed cylindrical shape, and an inner surface thereof is formed in a partial spherical shape corresponding to the spherical support portion 13a.
  • the spherical support portion 13a of the piston 13 fits in the shoe 14, and the piston 13 is rotatable around a center point that is the center of the spherical support portion 13a.
  • the shoe 14 includes, at its bottom portion, a flange 14a projecting in a radially outward direction and is arranged on the swash plate 15 such that the bottom portion thereof contacts the swash plate 15.
  • the swash plate 15 is formed in a substantially circular plate shape.
  • the swash plate 15 is provided in the casing 17 so as to be inclined such that an upper portion thereof is located on a rear side, and the rotating shaft 11 penetrates the vicinity of the center of the swash plate 15.
  • the swash plate 15 is provided on a front side of the cylinder block 12 and includes a supporting plate 21 on the cylinder block 12 side.
  • the supporting plate 21 is formed in an annular shape, and the plurality of shoes 14 are arranged on the supporting plate 21 at regular intervals in the circumferential direction.
  • a retainer plate 22 is provided on the plurality of shoes 14 so as to press the shoes 14 against the supporting plate 21.
  • the retainer plate 22 is formed in a substantially annular shape, and the rotating shaft 11 penetrates the center of the retainer plate 22 so as to be relatively rotatable with respect to the retainer plate 22.
  • Attachment holes 22a are formed on the retainer plate 22.
  • the attachment holes 22a are arranged at regular intervals in the circumferential direction. Opening portions of the shoes 14 are respectively inserted in the attachment holes 22a, and the retainer plate 22 contacts the flanges 14a.
  • a spherical bushing 23 is inserted in an inner hole of the retainer plate 22.
  • the spherical bushing 23 is formed in a substantially cylindrical shape and is externally attached to the rotating shaft 11 and the cylinder block 12.
  • the spherical bushing 23 is biased toward the supporting plate 21 by a plurality of pressing springs 40 provided at the cylinder block 12, and the retainer plate 22 is pressed against the supporting plate 21 by the spherical bushing 23.
  • the regulator 24 includes a plunger 25 configured to be movable in the front-rear direction, and the swash plate 15 is coupled to the plunger 25. Therefore, by causing the plunger 25 to move in the front-rear direction, the inclination angle of the swash plate is changed. Thus, the strokes of the pistons 13 can be adjusted, and the volumes of oil chambers 20a of the cylinders 20 can be changed.
  • Each of the oil chambers 20a is a space in the cylinder 20, the space being located on the rear side of a rear end surface of the piston 13.
  • Cylinder ports 26 respectively connected to the oil chambers 20a are formed at the cylinder block 12.
  • One cylinder port 26 is formed for one cylinder 20, that is, the cylinder ports 26 correspond one-to-one to the cylinders 20.
  • the cylinder ports 26 open on a rear end surface of the cylinder block 12, and the valve plate 16 is provided on this rear end surface.
  • the valve plate 16 is an annular plate-shaped member and is located between the cylinder block 12 and a rear end portion of the casing 17.
  • the valve plate 16 is fixed to the casing 17 by pin members, not shown, so as not to be relatively rotatable with respect to the casing 17.
  • the rotating shaft 11 is inserted through an inner hole of the valve plate 16, and the rotating shaft 11 and the valve plate 16 are configured to be relatively rotatable with respect to each other.
  • An inlet port 16a and an outlet port 16b are formed on the valve plate 16 located as above.
  • Each of the inlet port 16a and the outlet port 16b is formed in a substantially circular-arc shape.
  • the inlet port 16a and the outlet port 16b are located so as to be spaced apart from each other in the circumferential direction.
  • Each of the inlet port 16a and the outlet port 16b penetrates the valve plate 16 in the thickness direction.
  • its opening located on the cylinder block 12 side is connected to some of the cylinder ports 26. By rotating the cylinder block 12, a destination to which the cylinder port 26 is connected is alternately switched between the inlet port 16a and the outlet port 16b.
  • the other opening of the inlet port 16a is connected to a high-pressure passage 27 shown in Fig.
  • FIG. 4 the other opening of the outlet port 16b is connected to a low-pressure passage 28 shown in Fig. 4 .
  • each of the cylinders 20 is alternately connected to the high-pressure passage 27 and the low-pressure passage 28.
  • FIG. 1 for convenience of explanation, the positions of the inlet port 16a and the outlet port 16b are shifted in the circumferential direction from the actual positions of the inlet port 16a and the outlet port 16b.
  • a circuit configuration shown in Fig. 4 is one example for further improving the cooling effect. Even without this configuration, the cooling effect can be obtained by oil in a case.
  • a communication passage 29 shown in Fig. 4 is formed at the casing 17.
  • An internal space of the casing 17 and the low-pressure passage 28 are connected to each other through the communication passage 29. With this, a certain amount of operating oil flowing through the low-pressure passage 28 can be introduced through the communication passage 29 to the internal space of the casing 17 to be utilized as a cooling liquid.
  • the rotating shaft 11, the cylinder block 12, the pistons 13, and the like can be cooled by low-pressure, low-temperature operating oil.
  • the oil-pressure motor 1 configured as above, while the piston 13 moves from a top dead center where the piston retracts most in the cylinder 20 to a bottom dead center where the piston 13 projects most from the cylinder 20, the operating oil flowing through the high-pressure passage 27 is suctioned to the oil chamber 20a through the inlet port 16a. With this, the piston 13 is pressed forward by the operating oil. As a result, the shoe 14 is pressed against the swash plate 15. Since the swash plate 15 is inclined, the pressed shoe 14 slides on the swash plate 15 so as to move downward and revolves around the axis L1 in one direction along the circumferential direction. With this, the rotational force around the axis L1 is applied to the cylinder block 12, and the cylinder block 12 and the rotating shaft 11 rotate around the axis L1.
  • the oil chamber 20a is connected to the low-pressure passage 28 via the outlet port 16b.
  • the shoe 14 slides on the swash plate 15 so as to move upward and revolves around the axis L1 in one direction along the circumferential direction.
  • the piston 13 is pressed backward.
  • the operating oil in the oil chamber 20a is discharged through the outlet port 16b to the low-pressure passage 28.
  • the pistons 13 perform the reciprocating sliding in the front-rear direction, and the cylinder block 12 and the rotating shaft 11 are rotated around the axis L1.
  • the oil-pressure motor 1 configured to repeat the suction and discharge of the operating oil
  • the pistons 13 slide on the sliding surfaces 12b to perform the reciprocating sliding in the front-rear direction. Therefore, frictional heat is generated on the sliding surfaces 12b when sliding, and the surface temperature of the sliding surface 12b, especially the surface temperature of a region on the opening side, increases.
  • the clearance is formed between the outer surface of the piston 13 and the sliding surface 12b.
  • the pistons 13 are lubricated.
  • the frictional heat generated on the sliding surfaces 12b is reduced, and the sliding surfaces 12b are cooled by the lubricating oil.
  • the oil-pressure motor 1 by providing the clearances, the increase in the surface temperatures of the sliding surfaces 12b is suppressed.
  • the oil-pressure motor 1 further includes the cooling structure 30 of the cylinder block 12.
  • the cooling structure 30 of the cylinder block 12 includes cooling depressions 31.
  • the cooling depressions 31 are respectively formed at dividing walls 32 each located between two adjacent cylinders 20 and extend from the front end surface of the cylinder block 12 toward the rear end surface thereof in parallel with the axis L1.
  • a tip end of the cooling depression 31 is located on the cylinder block 12 front end surface side of the vicinity of the rear end surface of the piston 13 located at the bottom dead center, that is, the tip end of the cooling depression 31 is located on the front side of the vicinity of the rear end surface of the piston 13 located at the bottom dead center (see Fig. 3 ).
  • Each of the dividing walls 32 denotes an entire wall (region shown by a diamond net pattern in Fig.
  • Figs. 5B and 5C are graphs respectively showing surface temperatures and oil pressures at respective positions on the sliding surface 12b when the piston 13 is located at the bottom dead center (see Fig. 5A ).
  • a vertical axis shows a surface temperature T of the sliding surface 12b
  • a horizontal axis shows a distance d from the front end surface of the cylinder block 12.
  • a vertical axis shows an oil pressure P applied to the sliding surface 12b
  • a horizontal axis shows the distance d from the front end surface of the cylinder block 12.
  • the surface temperature of the sliding surface 12b and the oil pressure applied to the sliding surface 12b are different between the front side and rear side of the rear end surface of the piston 13 located at the bottom dead center.
  • a high pressure is applied to the sliding surface 12b over a widest range.
  • the tip end of the cooling depression 31 on the cylinder block 12 front end surface side of the rear end surface of the piston 13 the cooling performance of a region where the surface temperature becomes high can be improved while increasing the stiffness of a region where the oil pressure applied to the sliding surface 12b becomes high. With this, damages by the burnout of the cylinder 12 and the piston 13 can be prevented without decreasing a service limit pressure of the operating oil.
  • the cooling depression 31 extending as above is bent so as to project toward a radially inner side.
  • a region of the dividing wall 32 is reduced in thickness, the region being located between the sliding surface 12b and the outer peripheral surface 12a.
  • the operating oil (lubricating oil) in the clearance between the sliding surface 12b and the piston 13 can be prevented from increasing in temperature and exceeding the transition temperature, and the burnout of the sliding surface 12b by the decrease in the lubrication performance of the operating oil can also be prevented.
  • the surface temperature of the sliding surface 12b can be reduced without increasing the clearance between the sliding surface 12b and the piston 13 and forming oil grooves on the sliding surface 12b. Therefore, the cooling performance improves without decreasing the performance of the motor.
  • the cooling depression 31 is formed to satisfy 0.02D ⁇ tmin ⁇ 0.3D, where tmin denotes a minimum thickness of the portion between the sliding surface 12b and the outer peripheral surface 12b, and D denotes the inner diameter of the cylinder 20. More specifically, the cooling depression 31 is formed to satisfy 0.02D ⁇ t ⁇ 0.3D, where t denotes a thickness of a portion between the outer peripheral surface 12a and a region 12c (corresponding to a region located on the outer peripheral surface 12a side in the sliding surface 12b) located on a radially outer side in the sliding surface 12b, and D denotes the inner diameter of the cylinder 20.
  • the region 12c located on the radially outer side is a region spreading from an intersection point A1 toward both directions along the circumferential direction, the intersection point A1 being one of two points where the straight line L2 and the sliding surface 12b intersect with each other and being located on the radially outer side.
  • the region 12c is a region spreading from the intersection point A1 as a center toward both directions along the circumferential direction and having a center angle ⁇ , and the center angle ⁇ satisfies 30° ⁇ ⁇ ⁇ 180°.
  • the cooling depression 31 may be formed such that the thickness t around the sliding surface 12b satisfies 0.02D ⁇ t ⁇ 0.3D over a wider range than the range defined by the center angle ⁇ (for example, see Fig. 6 described below).
  • the cooling performance of the sliding surface 12b can be improved, and the increase in the surface temperature of the sliding surface 12b can be suppressed.
  • the temperature increase of the operating oil (lubricating oil) flowing through the clearance between the sliding surface 12b and the piston 13 can be suppressed, and the temperature of the operating oil can be prevented from increasing and exceeding the transition temperature. Therefore, the burnout of the sliding surface 12b by the decrease in the lubrication performance of the operating oil can be prevented.
  • the surface temperature of the sliding surface 12b can be decreased without increasing the clearance between the sliding surface 12b and the piston 13 and forming oil grooves on the sliding surface 12b, the cooling performance improves without decreasing the performance of the motor. Further, by setting the thickness t to 0.02D or more, the stiffness in the vicinity of the opening side of the region 12c located on the radially outer side in the sliding surface 12b can be secured. Even when the piston 13 performs the reciprocating sliding at high speed in operation, the damages in the vicinity of the opening side can be prevented.
  • a bottom surface of the cooling depression 31 is bent in an arch shape.
  • the bottom surface does not have to have the arch shape.
  • a cooling depression 31A of a cooling structure 30A may be formed along the sliding surface 12b to have a sharp tip shape, so that the thickness t of an entire semicircle located on the radially outer side in the sliding surface 12b may become uniform.
  • the shape of the cooling depression 31 does not have to be bent.
  • the bottom surface may be flat, or the bottom surface may be formed like a fin by forming depressions and projections thereon. Further, the vicinity of the tip end of the bottom surface of the cooling depression 31 is bent toward the tip end so as to be located on the radially outer side.
  • the vicinity of the tip end of the bottom surface does not have to be bent and may be flat up to the tip end (for example, see reference sign 41 shown by a chain double-dashed line in Fig. 3 ).
  • the tip end of the cooling depression 31 is located between the front end surface of the cylinder block 12 and the rear end surface of the piston 13 located at the bottom dead center.
  • the tip end of the cooling depression 31 may be located in the vicinity of the rear end surface.
  • the swash plate type liquid-pressure apparatus 1 is the oil-pressure motor.
  • the swash plate type liquid-pressure apparatus 1 may be the oil-pressure pump.
  • the cylinder block 12 is rotated by rotating the rotating shaft 11 by an electric motor or an engine.
  • the pistons 13 perform the reciprocating sliding.
  • the outlet port 16b is connected to the high-pressure passage 27, and the inlet port 16a is connected to the low-pressure passage 28.
  • the piston 13 moves from the top dead center to the bottom dead center, the operating oil is suctioned through the inlet port 16a to the oil chamber 20a.
  • the suctioned operating oil is compressed and ejected through the outlet port 16b to the high-pressure passage 27.
  • the pistons perform the reciprocating sliding in the cylinders 20 and slide on the sliding surfaces 12b. Therefore, as with the oil-pressure motor 1, the heat is generated on the sliding surfaces 12b.
  • the same operational advantages as the oil-pressure motor 1 can be obtained by the cooling structure 30 of the cylinder block 12.
  • the cooling structure 30 of the cylinder block 12 may be applied to an inclined shaft type liquid-pressure apparatus.
  • the inclined shaft type liquid-pressure apparatus even if the speed is increased, the surface temperature of the sliding surface 12b does not increase, unlike the swash plate type liquid-pressure apparatus 1. Therefore, higher operational advantages are obtained in the case of the swash plate type liquid-pressure apparatus.
  • the oil is used as the operating liquid, other liquids, such as water, may be used as the operating liquid.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Reciprocating Pumps (AREA)
  • Hydraulic Motors (AREA)
  • Details Of Reciprocating Pumps (AREA)
EP10859806.1A 2010-11-16 2010-11-16 Kühlstruktur für einen zylinderblock und hydraulische taumelscheibenvorrichtung damit Withdrawn EP2642123A4 (de)

Applications Claiming Priority (1)

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PCT/JP2010/006721 WO2012066593A1 (ja) 2010-11-16 2010-11-16 シリンダブロックの冷却構造、及びそれを有する斜板形液圧装置

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EP2642123A1 true EP2642123A1 (de) 2013-09-25
EP2642123A4 EP2642123A4 (de) 2017-10-04

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US (1) US20130000481A1 (de)
EP (1) EP2642123A4 (de)
JP (1) JP5444462B2 (de)
KR (1) KR101330768B1 (de)
CN (1) CN102630279A (de)
WO (1) WO2012066593A1 (de)

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JP6080626B2 (ja) * 2013-03-13 2017-02-15 川崎重工業株式会社 アキシャルピストンモータ
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JP2018076826A (ja) * 2016-11-10 2018-05-17 川崎重工業株式会社 シリンダブロックとそれを備えた斜板形液圧回転装置
JP6831711B2 (ja) 2017-02-01 2021-02-17 川崎重工業株式会社 液圧駆動システム
KR102348899B1 (ko) * 2021-11-01 2022-01-11 토비스유압 주식회사 사판식 유압모터 시스템
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Also Published As

Publication number Publication date
US20130000481A1 (en) 2013-01-03
CN102630279A (zh) 2012-08-08
KR20120083876A (ko) 2012-07-26
JP5444462B2 (ja) 2014-03-19
JPWO2012066593A1 (ja) 2014-05-12
KR101330768B1 (ko) 2013-11-18
WO2012066593A1 (ja) 2012-05-24
EP2642123A4 (de) 2017-10-04

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