WO2015174516A1 - Actuator - Google Patents

Actuator Download PDF

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Publication number
WO2015174516A1
WO2015174516A1 PCT/JP2015/064004 JP2015064004W WO2015174516A1 WO 2015174516 A1 WO2015174516 A1 WO 2015174516A1 JP 2015064004 W JP2015064004 W JP 2015064004W WO 2015174516 A1 WO2015174516 A1 WO 2015174516A1
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WO
WIPO (PCT)
Prior art keywords
nut
support
screw shaft
support nut
housing
Prior art date
Application number
PCT/JP2015/064004
Other languages
French (fr)
Japanese (ja)
Inventor
勉 富樫
秀生 斉藤
寛正 安武
Original Assignee
Thk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 Thk株式会社 filed Critical Thk株式会社
Publication of WO2015174516A1 publication Critical patent/WO2015174516A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
    • F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
    • F16H25/20—Screw mechanisms
    • F16H25/24—Elements essential to such mechanisms, e.g. screws, nuts

Definitions

  • the present invention relates to an actuator that includes a screw shaft and a ball screw nut that is screwed onto the screw shaft and linearly moves a movable body such as a table.
  • An actuator that includes a screw shaft and a ball screw nut that is screwed onto the screw shaft and linearly moves a movable body such as a table is known.
  • a movable body such as a table is attached to the ball screw nut.
  • the screw shaft is driven to rotate, the ball screw nut moves in the axial direction of the screw shaft, and a movable body such as a table moves in the axial direction of the screw shaft together with the ball screw nut.
  • Patent Document 1 proposes an invention in which an intermediate support is disposed between the ball screw nut and the end of the screw shaft, and the screw shaft is supported by the intermediate support.
  • the intermediate support includes a housing guided so as to be movable in the axial direction of the screw shaft, and a support nut accommodated in the housing.
  • An annular groove with zero lead is formed in the support nut.
  • a ball is disposed at the intersection of the annular groove of the support nut and the ball rolling groove of the screw shaft.
  • the support nut moves in the axial direction of the screw shaft at half the speed of the nut. For this reason, even if the nut moves in the axial direction of the screw shaft, the intermediate support can be positioned between the nut and the end of the screw shaft. The principle that the support nut moves at a speed half that of the ball screw nut will be described later.
  • the intermediate support in order to adjust the position of the intermediate support, is provided with a clutch.
  • the clutch includes a position restricting plate disposed at both ends in the axial direction of the support nut, a recess formed in the position restricting plate, a ball that fits into the recess, a spring that biases the ball toward the recess, A push screw for adjusting the biasing force.
  • an actuator with an intermediate support has a problem that when the reciprocating motion is repeated, the intermediate support is displaced in the axial direction of the screw shaft. This is presumably because the contact between the annular groove of the support nut and the ball, the contact between the ball rolling groove of the screw shaft and the ball fluctuates between the forward path and the return path, and the amount of ball revolution changes. Possible causes of contact fluctuation include parts processing error, part mounting posture, and the like. Since the movement of the ball of the support nut involves both rolling and sliding movements and is uncertain, the movement of the ball of the support nut itself is considered to be a factor causing contact fluctuation. Even if the actuator is actually reciprocated, the intermediate support that initially caused the displacement in one direction of the screw shaft may cause the displacement in the opposite direction from the middle.
  • the intermediate support If the intermediate support is misaligned, the intermediate support cannot be placed between the nut and the end of the screw shaft, and the intermediate support can support an object such as a nut or a support that supports both ends of the screw shaft. In such a case, these parts may be damaged.
  • an object of the present invention is to provide an actuator capable of easily rotating a support nut when an intermediate support moving in the axial direction of a screw shaft hits an object.
  • an aspect of the present invention is arranged between a screw shaft, a nut assembled to the screw shaft via a rolling element, and an axial end portion of the nut and the screw shaft.
  • a support nut Moving in the axial direction of the screw shaft, a support nut in which rolling elements are interposed between the screw shaft, a housing in which the support nut is accommodated, and an outer periphery of the support nut, A rolling support for rotatably supporting the support nut with respect to the housing; and the support for the housing in contact with an outer periphery of the support nut.
  • a resistance adjusting portion that restricts rotation of the nut for rotation and allows the support nut to rotate relative to the housing when movement of the intermediate support in the axial direction of the screw shaft is restricted. It is an actuator provided.
  • the rolling support portion that reduces the rotation resistance of the support nut relative to the housing is disposed on the outer periphery of the support nut, the rotation resistance of the support nut relative to the housing is reduced with respect to the screw nut.
  • the rotation resistance resistance caused by the rolling elements of the support nut “sliding” on the ball rolling groove of the screw shaft
  • the support nut can be reliably rotated.
  • the resistance adjustment part which controls rotation of the support nut with respect to a housing is provided, an intermediate
  • FIG. 5 (A) is an operation
  • FIG.5 (B) is an operation
  • FIG. 6A is a conceptual diagram illustrating the principle of correction (FIG. 6A shows a state where the intermediate support moves in the axial direction of the screw shaft
  • FIG. 6A shows a state where the intermediate support moves in the axial direction of the screw shaft
  • 6B shows a state where the intermediate support hits the stopper).
  • It is sectional drawing which shows the other example of the nut for support. It is a disassembled perspective view which shows the other example of the nut for support. It is a top view of the actuator of 2nd embodiment of this invention.
  • FIG. 1 is a perspective view of an actuator according to a first embodiment of the present invention.
  • the actuator of this embodiment includes a screw shaft 1, a ball screw nut 2 as a nut assembled to the screw shaft 1, and a pair of intermediate supports 4a disposed between the ball screw nut 2 and both ends of the screw shaft 1. , 4b and a motor 3 as a drive source for rotationally driving the screw shaft 1.
  • the screw shaft 1 is rotationally driven by the motor 3
  • the ball screw nut 2 reciprocates in the axial direction of the screw shaft 1, and the intermediate supports 4 a and 4 b move at a speed half that of the ball screw nut 2. Reciprocate in the direction.
  • Both ends of the screw shaft 1 in the length direction are rotatably supported by the pair of support brackets 5a and 5b.
  • the support brackets 5 a and 5 b are fixed to a base 6 that is elongated in the axial direction of the screw shaft 1.
  • Bearings 9a and 9b (see FIG. 6) for guiding the rotation of the screw shaft 1 are incorporated in the support brackets 5a and 5b.
  • a motor 3 as a drive source is connected to one end of the screw shaft 1 in the axial direction via a joint 7.
  • rubber stoppers 8a and 8b that contact the intermediate supports 4a and 4b are arranged inside the support brackets 5a and 5b.
  • a spiral ball rolling groove 1a in which a ball as a rolling element rolls is formed on the outer peripheral surface of the screw shaft 1.
  • a ball rolling groove 1a of the screw shaft 1 a ball of a ball screw nut 2 described later and a ball 51 of intermediate supports 4a and 4b described later roll.
  • the ball rolling groove 1a has a predetermined lead.
  • the number of strips of the ball rolling groove 1a is not particularly limited, and can be set as appropriate, such as one strip, two strips, and three strips.
  • the cross-sectional shape of the ball rolling groove 1a is a Gothic arch groove composed of two arcs.
  • a load ball rolling groove having a predetermined lead is formed on the inner peripheral surface of the ball screw nut 2 so as to face the ball rolling groove 1a of the screw shaft 1.
  • the cross-sectional shape of the load ball rolling groove is a Gothic arch groove composed of two arcs.
  • the ball screw nut 2 is provided with a circulating component such as a return pipe for circulating the ball.
  • a large number of balls are arranged in the ball circulation path including the loaded ball rolling groove of the ball screw nut 2.
  • the ball screw nut 2 is guided so as to be movable in the axial direction of the screw shaft 1 by a linear guide 11 as a guide portion.
  • the rotation of the ball screw nut 2 is limited by the linear guide 11.
  • the linear guide 11 includes a rail 11a elongated in the axial direction of the screw shaft 1, and a moving block 11b assembled so as to be movable along the rail 11a.
  • a housing 14 in which the ball screw nut 2 is accommodated is coupled to the moving block 11b.
  • a movable body such as a table (not shown) is attached to the housing 14.
  • a pair of intermediate supports 4a and 4b are disposed between the ball screw nut 2 and both ends of the screw shaft 1.
  • the intermediate supports 4a and 4b include a housing 42, a support nut 44 rotatably accommodated in the housing 42, and a linear guide 12 as a guide portion for guiding the housing 42 to move in the axial direction of the screw shaft 1.
  • the rail 11 a of the linear guide 12 is also used as the rail 11 a of the linear guide 11.
  • the moving block 12b is assembled to the rail 11a so as to be linearly movable.
  • the housing 42 is coupled to the moving block 12 b of the linear guide 12.
  • FIG. 2 and 3 are detailed views of the intermediate supports 4a and 4b.
  • FIG. 2 shows a perspective view of the intermediate supports 4a and 4b.
  • FIG. 3 is an exploded perspective view of the intermediate supports 4a and 4b.
  • the intermediate supports 4 a and 4 b include a housing 42 fixed to the moving block 12 b of the linear guide 12, a support nut 44 accommodated in the housing 42, and a support nut 44 with respect to the housing 42.
  • a bearing 45 as a rolling support portion that supports the rotation of the support nut 44 and a resistance adjustment portion 49 that restricts the rotation of the support nut 44 relative to the housing 42 are provided.
  • the housing 42 is formed with an accommodation hole 42a through which the screw shaft 1 passes.
  • a support nut 44 is accommodated in the accommodation hole 42a.
  • the outer periphery of the support nut 44 is supported by a bearing 45 as a rolling support portion so as to be capable of rolling motion.
  • the outer periphery of the support nut 44 is in contact with a contact member 46 as a resistance adjusting portion.
  • the bearing 45 is accommodated in the accommodation hole 42a.
  • the housing 42 is formed with a through hole 42 b that extends in the radial direction of the support nut 44 and is exposed on the inner peripheral surface of the housing hole 42 a of the housing 42.
  • a concave portion 42 c is formed at the intersection of the through hole 42 b and the inner peripheral surface of the housing hole 42 a of the housing 42.
  • the contact member 46 is accommodated in the recess 42 c so as to be movable in the radial direction of the support nut 44.
  • the contact member 46 is provided on the housing 42 side, and the contact member 46 on the housing 42 side contacts the outer periphery of the support nut 44.
  • the contact member 46 is formed in a rectangular parallelepiped.
  • a sliding surface 46 a of the contact member 46 that is in contact with the outer periphery of the support nut 44 is formed into a curved surface that constitutes a part of the cylinder and is aligned with the outer peripheral surface of the support nut 44.
  • the contact member 46 is made of resin.
  • a coil spring 47 as an elastic body that pushes the contact member 46 against the support nut 44 is accommodated in the through hole 42b.
  • a press screw 48 for adjusting the position of the coil spring 47 is screwed into the through hole 42b. The coil spring 47 is interposed between the push screw 48 and the contact member 46.
  • the coil spring 47 When the push screw 48 is tightened, the coil spring 47 is compressed, and the force with which the contact member 46 pushes the support nut 44 in the radial direction increases. When the push screw 48 is loosened, the coil spring 47 extends, and the force with which the contact member 46 pushes the support nut 44 in the radial direction becomes weak. The force by which the contact member 46 pushes the support nut 44 in the radial direction is adjusted to a predetermined pressure by the coil spring 47. This predetermined pressure will be described later.
  • the contact member 46, the coil spring 47, and the push screw 48 constitute a resistance adjusting unit 49.
  • the bearing 45 is a deep groove ball bearing and can apply a radial load and an axial load in both directions.
  • a ball 45c is interposed between the inner ring 45a and the outer ring 45b of the bearing 45 so as to be able to roll.
  • the bearing 45 is provided to reduce the rotation resistance of the support nut 44 relative to the housing 42.
  • the support nut 44 has a cylindrical shape.
  • the support nut 44 is assembled to the screw shaft 1 via a ball as a rolling element.
  • An annular groove 44 a with zero lead is formed on the inner peripheral surface of the support nut 44.
  • the number of the strips of the annular groove 44a may be one or more, and is not particularly limited. In this embodiment, two annular grooves 44a are formed.
  • the cross-sectional shape of the annular groove 44a is a Gothic arch groove composed of two arcs.
  • the lead of the support nut 44 may be in the vicinity of 0, and is not limited to 0.
  • FIG. 3 shows a case where the ball rolling groove 1a of the screw shaft 1 has two strips. There are two intersections in each annular groove 44a, and two balls 51 are arranged at two intersections with an interval of 180 ° in the circumferential direction.
  • FIG. 3 shows a cross-sectional view of the support nut 44. In FIG. 3, only one ball 51 is shown in the left annular groove 44a, but in reality, two balls 51 are also arranged in the left annular groove 44a.
  • a groove 44c into which the flange 44b and the C-shaped retaining ring are fitted is formed on the outer peripheral surface of the support nut 44.
  • the support nut 44 is coupled to the inner ring 45a of the bearing 45 by sandwiching the inner ring 45a of the bearing 45 between the flange 44b and the C-shaped retaining ring.
  • FIG. 4 is a conceptual diagram for explaining the principle that the support nut 44 moves in the axial direction of the screw shaft 1 by 1/2 of the lead when the screw shaft 1 is rotated once.
  • the ball screw nut 2 moves in the axial direction of the screw shaft 1 by the size of the lead (marked with a scale of 2 in FIG. 4).
  • the ball of the ball screw nut 2 revolves around the screw shaft 1.
  • the movement amount of the ball in the axial direction of the screw shaft 1 is 1 ⁇ 2 of the ball screw nut 2.
  • the ball 51 of the support nut 44 also moves in the axial direction by a half of the ball screw nut 2 when the screw shaft 1 is rotated once, similarly to the ball of the normal ball screw nut 2. This is because both the ball 51 of the support nut 44 and the ball of the ball screw nut 2 revolve while rolling in the ball rolling groove 1a of the screw shaft 1. Since the support nut 44 is formed with an annular groove 44 a having no lead, the movement amount of the support nut 44 is equal to the movement amount of the ball 51. Therefore, the support nut 44 moves in the axial direction of the screw shaft 1 by 1/2 of the lead. That is, the support nut 44 moves in the axial direction of the screw shaft 1 at a speed half that of the ball screw nut 2.
  • the intermediate supports 4a and 4b repeat reciprocating motion, the intermediate supports 4a and 4b are displaced in the axial direction of the screw shaft 1. It is assumed that the contact between the annular groove 44a of the support nut 44 and the ball 51 and the contact between the ball rolling groove 1a of the screw shaft 1 and the ball 51 fluctuate between the forward path and the return path.
  • the position of the intermediate supports 4a and 4b is adjusted by rotating the support nut 44. It is corrected.
  • the operation of the ball screw nut 2 includes moving the ball screw nut 2 in the axial direction by rotating the screw shaft 1, and as shown in FIG. 5B. There is an operation of moving the ball screw nut 2 in the axial direction by rotating the ball screw nut 2.
  • the operation of the support nut 44 includes the operation shown in FIG. 5 (A) and the operation shown in FIG. 5 (B), like the ball screw nut 2.
  • the rotation resistance R1 of the support nut 44 relative to the housing 42 (hereinafter simply referred to as resistance R1) is set to be the resistance R4 of the rotation of the support nut 44 relative to the screw shaft 1 (support nut).
  • 44 balls 51 need to be smaller than the resistance caused by “sliding” the ball rolling groove 1a of the screw shaft 1 (hereinafter simply referred to as resistance R4). If this relationship is reversed, when the intermediate supports 4a and 4b hit the stoppers 8a and 8b, the balls 51 of the support nuts 44 instead of rotating the support nuts 44 are moved through the ball rolling grooves 1a of the screw shaft 1. Sliding and wrinkles on the ball rolling groove 1a.
  • a bearing 45 is interposed between the housing 42 and the support nut 44 to reduce the resistance R1.
  • the resistance R1 is a resistance R2 of rotation of the support nut 44 with respect to the screw shaft 1 (a resistance caused by the ball 51 of the support nut 44 "rolling" in the ball rolling groove 1a of the screw shaft 1, hereinafter simply referred to as a resistance R2). ) Is set smaller.
  • the housing 42 is provided with a contact member 46 that pushes the support nut 44 with a predetermined pressure.
  • the pressure of the contact member 46 is the resistance R3 of the rotation of the support nut 44 against the housing 42 (the resistance when the support nut 44 whose rotation is restricted by the contact member 46 starts to rotate with respect to the housing 42, hereinafter simply the resistance R3. Is set to be larger than the resistance R2.
  • the resistance R3 becomes larger than the resistance R4.
  • the pressure of the contact member 46 is set so that the resistance R3 is smaller than the resistance R4. If the pressure of the contact member 46 is set in this manner, the support nut 44 rotates while sliding against the contact member 46 when the intermediate supports 4a and 4b hit the stoppers 8a and 8b.
  • the resistors R1 to R4 need only have a relationship of R1 ⁇ R2 ⁇ R3 ⁇ R4.
  • the bearing 45 that reduces the resistance of rotation of the support nut 44 relative to the housing 42 is disposed on the outer periphery of the support nut 44, the resistance R1 can be made smaller than the resistance R4. . For this reason, when the intermediate supports 4a and 4b moving in the axial direction of the screw shaft 1 hit an object such as the stoppers 8a and 8b, the support nut 44 can be reliably rotated.
  • the resistance R3 of the rotation of the support nut 44 relative to the housing 42 can be finely adjusted. Furthermore, the resistance R3 can be finely adjusted by making the contact member 46 made of resin.
  • FIG. 7 and 8 show another example of the support nut 44.
  • 7 shows a cross-sectional view of the support nut 54 assembled to the screw shaft 1
  • FIG. 8 shows an exploded perspective view of the support nut 54.
  • the support nut 54 in this example guides the rotation of the retainer 56 relative to the nut body 52, the retainer 56 that holds the ball 55 of the support nut 54, and the nut body 52 having the annular groove 52 a. And a bearing 57.
  • the nut body 52 is formed in a cylindrical shape. On the inner peripheral surface of the nut main body 52, a three-row annular groove 52a having zero leads is formed.
  • the number of the ball rolling grooves 1a of the screw shaft 1 of this embodiment is one.
  • a total of three annular grooves 52a have a total of three intersections with a single ball rolling groove 1a.
  • Three balls 55 are arranged at the three intersections. When viewed from the axial direction of the screw shaft 1, the three balls 55 are arranged at equal intervals in the circumferential direction.
  • the retainer 56 is cylindrical.
  • a total of three holes 56a are opened in the cage 56 at the positions where the balls 55 are arranged.
  • Bearings 57 are accommodated at both ends of the nut body 52 in the axial direction. The bearing 57 is interposed between the nut main body 52 and the retainer 56 and guides the retainer 56 from rotating.
  • the support nut 44 of this example since the ball 55 is held at a predetermined position by the cage 56, the ball 55 can be moved smoothly. Further, since the cage 56 is guided rotatably by the bearing 57, the sliding friction of the cage 56 can be eliminated. Further, since the balls 55 of the support nut 44 are arranged at equal intervals in the circumferential direction when viewed from the axial direction of the screw shaft 1, the support nut 44 is assembled obliquely with respect to the screw shaft 1. Can be prevented.
  • FIG. 9 shows a plan view of the actuator according to the second embodiment of the present invention.
  • middle support 4a, 4b differs from the actuator of 1st embodiment.
  • two rails 61a and two moving blocks 61b are used as a guide portion for guiding the ball screw nut 2.
  • a table 62 is bridged between the two moving blocks 61b.
  • the ball screw nut 2 is coupled to the table 62. Since the structure of the screw shaft 1 and the ball screw nut 2 is the same as that of the actuator of the first embodiment, the same reference numerals are given and description thereof is omitted.
  • wheels 64a and 64b traveling on the base 63 are used as guide portions for guiding the intermediate supports 4a and 4b.
  • the wheels 64a and 64b are rotatably attached to the intermediate supports 4a and 4b.
  • the guide portion can also be constituted by the wheels 64a and 64b as in this embodiment.
  • the intermediate support is applied to the stopper in front of the support portion, but it can also be applied to the support portion. Further, the intermediate support can be applied to the ball screw nut housing, or the intermediate support moving block and the ball screw nut moving block can be applied.
  • a linear guide and a wheel are used as the guide portion.
  • a spline, a bush, or the like can be used as long as it restricts rotation while allowing linear motion of the ball screw nut or the support nut. .
  • the support nut and the bearing are separated, but the support nut and the inner ring of the bearing can be integrated.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transmission Devices (AREA)

Abstract

Provided is an actuator capable of rotating a support nut and automatically correcting position displacement of intermediate supports that move in the axial direction of a screw shaft, when the intermediate supports come in contact with an object. The intermediate supports (4a, 4b) are arranged between an actuator nut (2) and an end section of the screw shaft (1). A support nut (44) is inserted into a housing (42) for the intermediate supports (4a, 4b). A rolling support section (45) that rotatably supports the support nut (44) relative to the housing (42) is provided in the outer circumference of the support nut (44). A resistance adjustment section (49) is provided that comes in contact with the outer circumference of the support nut (44). The resistance adjustment section (49) is configured so as to restrict the rotation of the support nut (44) relative to the housing (42) and, when the movement of the intermediate supports (4a, 4b) in the axial direction of the screw shaft (1) has been restricted, enables the support nut (44) to rotate relative to the housing (42).

Description

アクチュエータActuator
　本発明は、ねじ軸、ねじ軸に螺合するボールねじナットを備え、テーブル等の可動体を直線運動させるアクチュータに関する。 The present invention relates to an actuator that includes a screw shaft and a ball screw nut that is screwed onto the screw shaft and linearly moves a movable body such as a table.
　ねじ軸、ねじ軸に螺合するボールねじナットを備え、テーブル等の可動体を直線運動させるアクチュータが知られている。ボールねじナットには、テーブル等の可動体が取り付けられる。ねじ軸を回転駆動させると、ボールねじナットがねじ軸の軸方向に移動し、ボールねじナットと一緒にテーブル等の可動体がねじ軸の軸方向に移動する。 An actuator that includes a screw shaft and a ball screw nut that is screwed onto the screw shaft and linearly moves a movable body such as a table is known. A movable body such as a table is attached to the ball screw nut. When the screw shaft is driven to rotate, the ball screw nut moves in the axial direction of the screw shaft, and a movable body such as a table moves in the axial direction of the screw shaft together with the ball screw nut.
　近年、可動体のストロークを伸ばすために、ねじ軸の軸方向の長さを長くする要請がある。また、アクチュエータのコンパクト化を図るために、ねじ軸の軸径も小さくする要請がある。しかし、ねじ軸のスパンを長くし、ねじ軸の軸径を小さくすると、ねじ軸の危険回転数が下がる。このため、ねじ軸が共振し、ねじ軸が振れ回り易くなる。 Recently, in order to extend the stroke of the movable body, there is a demand for increasing the axial length of the screw shaft. In addition, there is a demand for reducing the diameter of the screw shaft in order to reduce the size of the actuator. However, if the span of the screw shaft is made longer and the shaft diameter of the screw shaft is made smaller, the dangerous rotational speed of the screw shaft is lowered. For this reason, the screw shaft resonates and the screw shaft easily swings.
　ねじ軸の振れ回りを防止するために、特許文献１には、ボールねじナットとねじ軸の端部との間に中間サポートを配置し、中間サポートでねじ軸を支持する発明が提案されている。このアクチュエータにおいて、中間サポートは、ねじ軸の軸方向に移動可能に案内されたハウジングと、ハウジングに収納されるサポート用ナットと、を備える。サポート用ナットには、リードが０の環状溝が形成される。サポート用ナットの環状溝とねじ軸のボール転走溝との交点に、ボールが配置される。 In order to prevent the screw shaft from swinging around, Patent Document 1 proposes an invention in which an intermediate support is disposed between the ball screw nut and the end of the screw shaft, and the screw shaft is supported by the intermediate support. . In this actuator, the intermediate support includes a housing guided so as to be movable in the axial direction of the screw shaft, and a support nut accommodated in the housing. An annular groove with zero lead is formed in the support nut. A ball is disposed at the intersection of the annular groove of the support nut and the ball rolling groove of the screw shaft.
　ねじ軸を回転駆動させると、サポート用ナットは、ナットの１／２の速度でねじ軸の軸方向に移動する。このため、ナットがねじ軸の軸方向に移動しても、中間サポートをナットとねじ軸の端部との中間に位置させることができる。サポート用ナットがボールねじナットの１／２の速度で移動する原理は後述する。 When the screw shaft is driven to rotate, the support nut moves in the axial direction of the screw shaft at half the speed of the nut. For this reason, even if the nut moves in the axial direction of the screw shaft, the intermediate support can be positioned between the nut and the end of the screw shaft. The principle that the support nut moves at a speed half that of the ball screw nut will be described later.
　特許文献１に記載の発明において、中間サポートの位置を調整するために、中間サポートにはクラッチが設けられる。クラッチは、サポート用ナットの軸方向の両端部に配置される位置規制板と、位置規制板に形成される凹部と、凹部に嵌まるボールと、ボールを凹部に付勢するスプリングと、スプリングの付勢力を調整する押しねじと、を備える。中間サポートの位置を調整するとき、押しねじを緩め、位置規制板に対してサポート用ナットを回転できるようにする。手動によってサポート用ナットを回転させ、中間サポートの位置の調整が完了したら、押しねじを締め、サポート用ナットを回転できないようにする。 In the invention described in Patent Document 1, in order to adjust the position of the intermediate support, the intermediate support is provided with a clutch. The clutch includes a position restricting plate disposed at both ends in the axial direction of the support nut, a recess formed in the position restricting plate, a ball that fits into the recess, a spring that biases the ball toward the recess, A push screw for adjusting the biasing force. When adjusting the position of the intermediate support, loosen the push screw so that the support nut can be rotated relative to the position restricting plate. After manually rotating the support nut and adjusting the position of the intermediate support, tighten the push screw to prevent the support nut from rotating.
特開２０１０－１９６９０１号公報JP 2010-196901 A
　しかし、中間サポート付きのアクチュエータにあっては、往復運動を繰り返すと、中間サポートがねじ軸の軸方向に位置ずれを起こすという課題がある。往路と復路とで、サポート用ナットの環状溝とボールとの接点、ねじ軸のボール転走溝とボールとの接点が変動し、ボールの公転量が変動するからであると推測される。接点変動を起こす原因としては、部品の加工誤差、部品の取り付け姿勢等が考えられる。サポート用ナットのボールの運動は、転がり運動とすべり運動の両者を伴い、不確定なものであるから、サポート用ナットのボールの運動自体も接点変動を起こす一因であると考えられる。実際にアクチュエータを往復運動させても、最初にねじ軸の一方向に位置ずれを起こしていた中間サポートが、途中から反対方向に位置ずれを起こすこともある。中間サポートが位置ずれを起こすと、中間サポートをナットとねじ軸の端部との中間に配置することができないばかりでなく、中間サポートがナット、ねじ軸の両端部を支持する支持部等の物体に当たり、これらの部品が破損するおそれがある。 However, an actuator with an intermediate support has a problem that when the reciprocating motion is repeated, the intermediate support is displaced in the axial direction of the screw shaft. This is presumably because the contact between the annular groove of the support nut and the ball, the contact between the ball rolling groove of the screw shaft and the ball fluctuates between the forward path and the return path, and the amount of ball revolution changes. Possible causes of contact fluctuation include parts processing error, part mounting posture, and the like. Since the movement of the ball of the support nut involves both rolling and sliding movements and is uncertain, the movement of the ball of the support nut itself is considered to be a factor causing contact fluctuation. Even if the actuator is actually reciprocated, the intermediate support that initially caused the displacement in one direction of the screw shaft may cause the displacement in the opposite direction from the middle. If the intermediate support is misaligned, the intermediate support cannot be placed between the nut and the end of the screw shaft, and the intermediate support can support an object such as a nut or a support that supports both ends of the screw shaft. In such a case, these parts may be damaged.
　ねじ軸の軸方向に移動する中間サポートが物体に当たったとき、サポート用ナットが回転できるようにすれば、中間サポートの位置を自動的に補正できる。特許文献１に記載のアクチュエータおいては、クラッチが設けられているものの、中間サポートが物体に当たったとき、クラッチによってサポート用ナットを回転させることが困難であるという課題がある。 When the intermediate support moving in the axial direction of the screw shaft hits the object, the position of the intermediate support can be automatically corrected if the support nut can be rotated. In the actuator described in Patent Document 1, although a clutch is provided, there is a problem that when the intermediate support hits an object, it is difficult to rotate the support nut by the clutch.
　そこで、本発明は、ねじ軸の軸方向に移動する中間サポートが物体に当たったとき、サポート用ナットを容易に回転させることができるアクチュエータを提供することを目的とする。 Therefore, an object of the present invention is to provide an actuator capable of easily rotating a support nut when an intermediate support moving in the axial direction of a screw shaft hits an object.
　上記課題を解決するために、本発明の一態様は、ねじ軸と、前記ねじ軸に転動体を介して組み付けられるナットと、前記ナットと前記ねじ軸の軸方向の端部との間に配置される中間サポートと、を備え、前記ねじ軸を回転駆動させることによって、前記ナット及び前記中間サポートを前記ねじ軸の軸方向に移動させるアクチュエータにおいて、前記中間サポートは、前記ねじ軸の回転に応じて前記ねじ軸の軸方向に移動し、前記ねじ軸との間に転動体が介在されるサポート用ナットと、前記サポート用ナットが収容されるハウジングと、前記サポート用ナットの外周に配置され、前記ハウジングに対して前記サポート用ナットを回転可能に支持する転がり支持部と、前記サポート用ナットの外周に接して、前記ハウジングに対する前記サポート用ナットの回転を規制すると共に、前記ねじ軸の軸方向への前記中間サポートの移動が規制されたとき、前記ハウジングに対して前記サポート用ナットが回転できるようにする抵抗調整部と、を備えるアクチュエータである。 In order to solve the above-described problem, an aspect of the present invention is arranged between a screw shaft, a nut assembled to the screw shaft via a rolling element, and an axial end portion of the nut and the screw shaft. An intermediate support, and an actuator that moves the nut and the intermediate support in an axial direction of the screw shaft by rotationally driving the screw shaft, wherein the intermediate support responds to the rotation of the screw shaft. Moving in the axial direction of the screw shaft, a support nut in which rolling elements are interposed between the screw shaft, a housing in which the support nut is accommodated, and an outer periphery of the support nut, A rolling support for rotatably supporting the support nut with respect to the housing; and the support for the housing in contact with an outer periphery of the support nut. A resistance adjusting portion that restricts rotation of the nut for rotation and allows the support nut to rotate relative to the housing when movement of the intermediate support in the axial direction of the screw shaft is restricted. It is an actuator provided.
　本発明によれば、サポート用ナットの外周にハウジングに対するサポート用ナットの回転の抵抗を小さくする転がり支持部を配置するので、ハウジングに対するサポート用ナットの回転の抵抗を、ねじ軸に対するサポート用ナットの回転の抵抗（サポート用ナットの転動体がねじ軸のボール転走溝を「すべる」ことに起因する抵抗）よりも小さくすることができる。このため、ねじ軸の軸方向に移動する中間サポートが物体に当たったとき、サポート用ナットを確実に回転させることができる。また、ハウジングに対するサポート用ナットの回転を規制する抵抗調整部を備えるので、中間サポートをねじ軸の軸方向に移動させることができる。 According to the present invention, since the rolling support portion that reduces the rotation resistance of the support nut relative to the housing is disposed on the outer periphery of the support nut, the rotation resistance of the support nut relative to the housing is reduced with respect to the screw nut. The rotation resistance (resistance caused by the rolling elements of the support nut “sliding” on the ball rolling groove of the screw shaft) can be made smaller. For this reason, when the intermediate support moving in the axial direction of the screw shaft hits the object, the support nut can be reliably rotated. Moreover, since the resistance adjustment part which controls rotation of the support nut with respect to a housing is provided, an intermediate | middle support can be moved to the axial direction of a screw shaft.
本発明の第一の実施形態のアクチュエータの斜視図である。It is a perspective view of the actuator of 1st embodiment of this invention. 本実施形態の中間サポートの斜視図である。It is a perspective view of the intermediate support of this embodiment. 本実施形態の中間サポートの分解斜視図である。It is a disassembled perspective view of the intermediate support of this embodiment. サポート用ナットがリードの１／２だけねじ軸の軸方向に移動する原理を説明する概念図である。It is a conceptual diagram explaining the principle which the nut for support moves to the axial direction of a screw shaft only 1/2 of a lead | read | reed. ボールねじナットの動作を説明する図である（図５（Ａ）はねじ軸を回転させたときの動作図であり、図５（Ｂ）はナットを回転させたときの動作図である）。It is a figure explaining operation | movement of a ball screw nut (FIG. 5 (A) is an operation | movement figure when rotating a screw shaft, FIG.5 (B) is an operation | movement figure when rotating a nut). 補正の原理を説明する概念図である（図６（１）は、中間サポートがねじ軸の軸方向に移動する状態を示し、図６（２）は中間サポートがストッパに当たった状態を示す）。FIG. 6A is a conceptual diagram illustrating the principle of correction (FIG. 6A shows a state where the intermediate support moves in the axial direction of the screw shaft, and FIG. 6B shows a state where the intermediate support hits the stopper). . サポート用ナットの他の例を示す断面図である。It is sectional drawing which shows the other example of the nut for support. サポート用ナットの他の例を示す分解斜視図である。It is a disassembled perspective view which shows the other example of the nut for support. 本発明の第二の実施形態のアクチュエータの平面図である。It is a top view of the actuator of 2nd embodiment of this invention.
　以下添付図面に基づいて、本発明の実施形態のアクチュエータを詳細に説明する。図１は、本発明の第一の実施形態のアクチュエータの斜視図を示す。本実施形態のアクチュエータは、ねじ軸１と、ねじ軸１に組み付けられるナットとしてのボールねじナット２と、ボールねじナット２とねじ軸１の両端部との中間に配置される一対の中間サポート４ａ，４ｂと、ねじ軸１を回転駆動させる駆動源としてのモータ３と、を備える。モータ３によってねじ軸１を回転駆動させると、ボールねじナット２がねじ軸１の軸方向に往復運動し、中間サポート４ａ，４ｂがボールねじナット２の１／２の速度でねじ軸１の軸方向に往復運動する。 Hereinafter, an actuator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of an actuator according to a first embodiment of the present invention. The actuator of this embodiment includes a screw shaft 1, a ball screw nut 2 as a nut assembled to the screw shaft 1, and a pair of intermediate supports 4a disposed between the ball screw nut 2 and both ends of the screw shaft 1. , 4b and a motor 3 as a drive source for rotationally driving the screw shaft 1. When the screw shaft 1 is rotationally driven by the motor 3, the ball screw nut 2 reciprocates in the axial direction of the screw shaft 1, and the intermediate supports 4 a and 4 b move at a speed half that of the ball screw nut 2. Reciprocate in the direction.
　ねじ軸１の長さ方向の両端部は、一対の支持ブラケット５ａ，５ｂに回転可能に支持される。支持ブラケット５ａ，５ｂは、ねじ軸１の軸方向に細長いベース６に固定される。支持ブラケット５ａ，５ｂには、ねじ軸１の回転を案内するベアリング９ａ，９ｂ（図６参照）が組み込まれる。ねじ軸１の軸方向の一端部には、継手７を介して駆動源としてのモータ３が連結される。支持ブラケット５ａ，５ｂの内側には、中間サポート４ａ，４ｂに当たるゴム製のストッパ８ａ，８ｂ（図６参照）が配置される。 Both ends of the screw shaft 1 in the length direction are rotatably supported by the pair of support brackets 5a and 5b. The support brackets 5 a and 5 b are fixed to a base 6 that is elongated in the axial direction of the screw shaft 1. Bearings 9a and 9b (see FIG. 6) for guiding the rotation of the screw shaft 1 are incorporated in the support brackets 5a and 5b. A motor 3 as a drive source is connected to one end of the screw shaft 1 in the axial direction via a joint 7. Inside the support brackets 5a and 5b, rubber stoppers 8a and 8b (see FIG. 6) that contact the intermediate supports 4a and 4b are arranged.
　ねじ軸１の外周面には、転動体としてのボールが転がり運動する螺旋状のボール転走溝１ａが形成される。ねじ軸１のボール転走溝１ａには、後述するボールねじナット２のボール、及び後述する中間サポート４ａ，４ｂのボール５１が転がり運動する。ボール転走溝１ａは所定のリードを持つ。ボール転走溝１ａの条数は、特に限定されるものではなく、一条、二条、三条等適宜設定することができる。ボール転走溝１ａの断面形状は、二つの円弧からなるゴシックアーチ溝である。 A spiral ball rolling groove 1a in which a ball as a rolling element rolls is formed on the outer peripheral surface of the screw shaft 1. In a ball rolling groove 1a of the screw shaft 1, a ball of a ball screw nut 2 described later and a ball 51 of intermediate supports 4a and 4b described later roll. The ball rolling groove 1a has a predetermined lead. The number of strips of the ball rolling groove 1a is not particularly limited, and can be set as appropriate, such as one strip, two strips, and three strips. The cross-sectional shape of the ball rolling groove 1a is a Gothic arch groove composed of two arcs.
　ボールねじナット２の内周面には、ねじ軸１のボール転走溝１ａに対向し、所定のリードを持つ負荷ボール転走溝が形成される。負荷ボール転走溝の断面形状は、二つの円弧からなるゴシックアーチ溝である。ボールねじナット２には、ボールを循環させるためリターンパイプ等の循環部品が設けられる。ボールねじナット２の負荷ボール転走溝を含むボール循環路には、多数のボールが配列される。ねじ軸１を一回転させたとき、ボールねじナット２は所定のリードだけねじ軸１の軸方向に移動する。 A load ball rolling groove having a predetermined lead is formed on the inner peripheral surface of the ball screw nut 2 so as to face the ball rolling groove 1a of the screw shaft 1. The cross-sectional shape of the load ball rolling groove is a Gothic arch groove composed of two arcs. The ball screw nut 2 is provided with a circulating component such as a return pipe for circulating the ball. A large number of balls are arranged in the ball circulation path including the loaded ball rolling groove of the ball screw nut 2. When the screw shaft 1 is rotated once, the ball screw nut 2 moves in the axial direction of the screw shaft 1 by a predetermined lead.
　ボールねじナット２は、案内部としてのリニアガイド１１によって、ねじ軸１の軸方向に移動可能に案内される。ボールねじナット２の回転は、リニアガイド１１によって制限される。リニアガイド１１は、ねじ軸１の軸方向に細長いレール１１ａと、レール１１ａに沿って移動可能に組み付けられる移動ブロック１１ｂと、を備える。移動ブロック１１ｂには、ボールねじナット２が収容されるハウジング１４が結合される。ハウジング１４には、図示しないテーブル等の可動体が取り付けられる。 The ball screw nut 2 is guided so as to be movable in the axial direction of the screw shaft 1 by a linear guide 11 as a guide portion. The rotation of the ball screw nut 2 is limited by the linear guide 11. The linear guide 11 includes a rail 11a elongated in the axial direction of the screw shaft 1, and a moving block 11b assembled so as to be movable along the rail 11a. A housing 14 in which the ball screw nut 2 is accommodated is coupled to the moving block 11b. A movable body such as a table (not shown) is attached to the housing 14.
　ボールねじナット２とねじ軸１の両端部との中間には、一対の中間サポート４ａ，４ｂが配置される。中間サポート４ａ，４ｂは、ハウジング４２と、ハウジング４２に回転可能に収容されるサポート用ナット４４と、ハウジング４２がねじ軸１の軸方向に移動するのを案内する案内部としてのリニアガイド１２と、を備える。リニアガイド１２のレール１１ａは、リニアガイド１１のレール１１ａと兼用されている。レール１１ａには、移動ブロック１２ｂが直線運動可能に組み付けられる。ハウジング４２はリニアガイド１２の移動ブロック１２ｂに結合される。 A pair of intermediate supports 4a and 4b are disposed between the ball screw nut 2 and both ends of the screw shaft 1. The intermediate supports 4a and 4b include a housing 42, a support nut 44 rotatably accommodated in the housing 42, and a linear guide 12 as a guide portion for guiding the housing 42 to move in the axial direction of the screw shaft 1. . The rail 11 a of the linear guide 12 is also used as the rail 11 a of the linear guide 11. The moving block 12b is assembled to the rail 11a so as to be linearly movable. The housing 42 is coupled to the moving block 12 b of the linear guide 12.
　図２及び図３は、中間サポート４ａ，４ｂの詳細図を示す。図２は、中間サポート４ａ，４ｂの斜視図を示す。図３は、中間サポート４ａ，４ｂの分解斜視図を示す。図３に示すように、中間サポート４ａ，４ｂは、リニアガイド１２の移動ブロック１２ｂに固定されるハウジング４２と、ハウジング４２に収納されるサポート用ナット４４と、ハウジング４２に対してサポート用ナット４４を回転可能に支持する転がり支持部としてのベアリング４５と、ハウジング４２に対するサポート用ナット４４の回転を規制する抵抗調整部４９と、を備える。 2 and 3 are detailed views of the intermediate supports 4a and 4b. FIG. 2 shows a perspective view of the intermediate supports 4a and 4b. FIG. 3 is an exploded perspective view of the intermediate supports 4a and 4b. As shown in FIG. 3, the intermediate supports 4 a and 4 b include a housing 42 fixed to the moving block 12 b of the linear guide 12, a support nut 44 accommodated in the housing 42, and a support nut 44 with respect to the housing 42. A bearing 45 as a rolling support portion that supports the rotation of the support nut 44 and a resistance adjustment portion 49 that restricts the rotation of the support nut 44 relative to the housing 42 are provided.
　図２に示すように、ハウジング４２には、ねじ軸１が貫通する収容孔４２ａが形成される。収容孔４２ａ内には、サポート用ナット４４が収容される。サポート用ナット４４は、その外周が、転がり支持部としてのベアリング４５で転がり運動可能に支持される。そして、サポート用ナット４４は、その外周が抵抗調整部としての接触部材４６に接する。ベアリング４５は、収容孔４２ａ内に収容される。ハウジング４２には、サポート用ナット４４の半径方向に伸び、ハウジング４２の収容孔４２ａの内周面に露出する貫通孔４２ｂが形成される。貫通孔４２ｂとハウジング４２の収容孔４２ａの内周面との交差部には、凹部４２ｃが形成される。凹部４２ｃには、接触部材４６がサポート用ナット４４の半径方向に移動可能に収容される。接触部材４６はハウジング４２側に設けられていて、ハウジング４２側の接触部材４６がサポート用ナット４４の外周に接する。 As shown in FIG. 2, the housing 42 is formed with an accommodation hole 42a through which the screw shaft 1 passes. A support nut 44 is accommodated in the accommodation hole 42a. The outer periphery of the support nut 44 is supported by a bearing 45 as a rolling support portion so as to be capable of rolling motion. The outer periphery of the support nut 44 is in contact with a contact member 46 as a resistance adjusting portion. The bearing 45 is accommodated in the accommodation hole 42a. The housing 42 is formed with a through hole 42 b that extends in the radial direction of the support nut 44 and is exposed on the inner peripheral surface of the housing hole 42 a of the housing 42. A concave portion 42 c is formed at the intersection of the through hole 42 b and the inner peripheral surface of the housing hole 42 a of the housing 42. The contact member 46 is accommodated in the recess 42 c so as to be movable in the radial direction of the support nut 44. The contact member 46 is provided on the housing 42 side, and the contact member 46 on the housing 42 side contacts the outer periphery of the support nut 44.
　接触部材４６は、直方体に形成される。接触部材４６の、サポート用ナット４４の外周に接する摺動面４６ａは、サポート用ナット４４の外周面に合わせた、円筒の一部を構成する曲面に形成される。接触部材４６は、樹脂製である。貫通孔４２ｂ内には、接触部材４６をサポート用ナット４４に押す弾性体としてのコイルばね４７が収容される。貫通孔４２ｂには、コイルばね４７の位置を調整するための押しねじ４８が螺合する。コイルばね４７は、押しねじ４８と接触部材４６との間に介在する。押しねじ４８を締めると、コイルばね４７が圧縮され、接触部材４６がサポート用ナット４４を半径方向に押す力が大きくなる。押しねじ４８を緩めると、コイルばね４７が伸長し、接触部材４６がサポート用ナット４４を半径方向に押す力が弱くなる。コイルばね４７によって、接触部材４６がサポート用ナット４４を半径方向に押す力が所定の圧力に調整される。この所定の圧力については後述する。接触部材４６、コイルばね４７、押しねじ４８が抵抗調整部４９を構成する。 The contact member 46 is formed in a rectangular parallelepiped. A sliding surface 46 a of the contact member 46 that is in contact with the outer periphery of the support nut 44 is formed into a curved surface that constitutes a part of the cylinder and is aligned with the outer peripheral surface of the support nut 44. The contact member 46 is made of resin. A coil spring 47 as an elastic body that pushes the contact member 46 against the support nut 44 is accommodated in the through hole 42b. A press screw 48 for adjusting the position of the coil spring 47 is screwed into the through hole 42b. The coil spring 47 is interposed between the push screw 48 and the contact member 46. When the push screw 48 is tightened, the coil spring 47 is compressed, and the force with which the contact member 46 pushes the support nut 44 in the radial direction increases. When the push screw 48 is loosened, the coil spring 47 extends, and the force with which the contact member 46 pushes the support nut 44 in the radial direction becomes weak. The force by which the contact member 46 pushes the support nut 44 in the radial direction is adjusted to a predetermined pressure by the coil spring 47. This predetermined pressure will be described later. The contact member 46, the coil spring 47, and the push screw 48 constitute a resistance adjusting unit 49.
　ベアリング４５は、深溝玉軸受であり、ラジアル荷重、両方向のアキシャル荷重を負荷できる。ベアリング４５の内輪４５ａと外輪４５ｂとの間には、転がり運動可能にボール４５ｃが介在する。ベアリング４５は、ハウジング４２に対するサポート用ナット４４の回転の抵抗を小さくするために設けられる。 The bearing 45 is a deep groove ball bearing and can apply a radial load and an axial load in both directions. A ball 45c is interposed between the inner ring 45a and the outer ring 45b of the bearing 45 so as to be able to roll. The bearing 45 is provided to reduce the rotation resistance of the support nut 44 relative to the housing 42.
　サポート用ナット４４は、円筒形である。サポート用ナット４４は、転動体としてのボールを介してねじ軸１に組み付けられる。サポート用ナット４４の内周面には、リードが０の環状溝４４ａが形成される。環状溝４４ａの条数は一条以上であればよく、特に限定されるものではない。この実施形態では、二条の環状溝４４ａが形成される。環状溝４４ａの断面形状は、二つの円弧からなるゴシックアーチ溝である。なお、サポート用ナット４４のリードは０近傍であればよく、０に限られることはない。 The support nut 44 has a cylindrical shape. The support nut 44 is assembled to the screw shaft 1 via a ball as a rolling element. An annular groove 44 a with zero lead is formed on the inner peripheral surface of the support nut 44. The number of the strips of the annular groove 44a may be one or more, and is not particularly limited. In this embodiment, two annular grooves 44a are formed. The cross-sectional shape of the annular groove 44a is a Gothic arch groove composed of two arcs. The lead of the support nut 44 may be in the vicinity of 0, and is not limited to 0.
　リードが０の環状溝４４ａと所定のリードの一条のボール転走溝１ａとを組みわせると、一つの交点が存在する。この交点にサポート用ナット４４のボール５１が配置される。この図３には、ねじ軸１のボール転走溝１ａが二条の場合が示されている。各環状溝４４ａに二つの交点が存在し、二つの交点に二つのボール５１が円周方向に１８０°の間隔を空けて配置される。図３には、サポート用ナット４４の断面図が示されている。図３中左側の環状溝４４ａには、ボール５１が一つのみ示されているが、実際には、左側の環状溝４４ａにも二つのボール５１が配置されている。 When an annular groove 44a with a lead of 0 and a ball rolling groove 1a of a predetermined lead are combined, there is one intersection. The ball 51 of the support nut 44 is disposed at this intersection. FIG. 3 shows a case where the ball rolling groove 1a of the screw shaft 1 has two strips. There are two intersections in each annular groove 44a, and two balls 51 are arranged at two intersections with an interval of 180 ° in the circumferential direction. FIG. 3 shows a cross-sectional view of the support nut 44. In FIG. 3, only one ball 51 is shown in the left annular groove 44a, but in reality, two balls 51 are also arranged in the left annular groove 44a.
　サポート用ナット４４の外周面には、フランジ４４ｂ及びＣ形止め輪が嵌められる溝４４ｃが形成される。フランジ４４ｂとＣ形止め輪との間でベアリング４５の内輪４５ａを挟むことで、サポート用ナット４４がベアリング４５の内輪４５ａに結合される。 A groove 44c into which the flange 44b and the C-shaped retaining ring are fitted is formed on the outer peripheral surface of the support nut 44. The support nut 44 is coupled to the inner ring 45a of the bearing 45 by sandwiching the inner ring 45a of the bearing 45 between the flange 44b and the C-shaped retaining ring.
　図４は、ねじ軸１を１回転させたとき、サポート用ナット４４がリードの１／２だけねじ軸１の軸方向に移動する原理を説明する概念図である。ねじ軸１を１回転させるとき、ボールねじナット２は、リードの大きさ（図４に２の目盛を附す）の分だけねじ軸１の軸方向に移動する。このとき、ボールねじナット２のボールは、ねじ軸１の周囲を公転する。このボールの、ねじ軸１の軸方向の移動量は、ボールねじナット２の１／２である。 FIG. 4 is a conceptual diagram for explaining the principle that the support nut 44 moves in the axial direction of the screw shaft 1 by 1/2 of the lead when the screw shaft 1 is rotated once. When the screw shaft 1 is rotated once, the ball screw nut 2 moves in the axial direction of the screw shaft 1 by the size of the lead (marked with a scale of 2 in FIG. 4). At this time, the ball of the ball screw nut 2 revolves around the screw shaft 1. The movement amount of the ball in the axial direction of the screw shaft 1 is ½ of the ball screw nut 2.
　サポート用ナット４４のボール５１も、通常のボールねじナット２のボールと同様に、ねじ軸１を１回転させると、ボールねじナット２の１／２だけ軸方向に移動する。サポート用ナット４４のボール５１もボールねじナット２のボールも、ねじ軸１のボール転走溝１ａを転がりながら公転するからである。サポート用ナット４４には、リードが０の環状溝４４ａが形成されるので、サポート用ナット４４の移動量は、ボール５１の移動量に等しい。このため、サポート用ナット４４はリードの１／２だけねじ軸１の軸方向に移動する。すなわち、サポート用ナット４４は、ボールねじナット２の１／２の速度でねじ軸１の軸方向に移動する。 The ball 51 of the support nut 44 also moves in the axial direction by a half of the ball screw nut 2 when the screw shaft 1 is rotated once, similarly to the ball of the normal ball screw nut 2. This is because both the ball 51 of the support nut 44 and the ball of the ball screw nut 2 revolve while rolling in the ball rolling groove 1a of the screw shaft 1. Since the support nut 44 is formed with an annular groove 44 a having no lead, the movement amount of the support nut 44 is equal to the movement amount of the ball 51. Therefore, the support nut 44 moves in the axial direction of the screw shaft 1 by 1/2 of the lead. That is, the support nut 44 moves in the axial direction of the screw shaft 1 at a speed half that of the ball screw nut 2.
　中間サポート４ａ，４ｂが往復運動を繰り返すと、中間サポート４ａ，４ｂは、ねじ軸１の軸方向に位置ずれを起こす。往路と復路とで、サポート用ナット４４の環状溝４４ａとボール５１との接点、ねじ軸１のボール転走溝１ａとボール５１との接点が変動することが原因であると推測される。本実施形態では、サポート用ナット４４が位置ずれを起こし、中間サポート４ａ，４ｂがストッパ８ａ，８ｂ等の物体に当たっとき、サポート用ナット４４を回転させることによって、中間サポート４ａ，４ｂの位置を補正している。 When the intermediate supports 4a and 4b repeat reciprocating motion, the intermediate supports 4a and 4b are displaced in the axial direction of the screw shaft 1. It is assumed that the contact between the annular groove 44a of the support nut 44 and the ball 51 and the contact between the ball rolling groove 1a of the screw shaft 1 and the ball 51 fluctuate between the forward path and the return path. In the present embodiment, when the support nut 44 is displaced and the intermediate supports 4a and 4b hit an object such as the stoppers 8a and 8b, the position of the intermediate supports 4a and 4b is adjusted by rotating the support nut 44. It is corrected.
　図５及び図６を参照して、補正の原理を説明する。ボールねじナット２の動作には、図５（Ａ）に示すように、ねじ軸１を回転させることによって、ボールねじナット２を軸方向に移動させる動作と、図５（Ｂ）に示すように、ボールねじナット２を回転させることによって、ボールねじナット２を軸方向に移動させる動作と、がある。サポート用ナット４４の動作にも、ボールねじナット２と同様に、図５（Ａ）に示す動作と図５（Ｂ）に示す動作とがある。 The principle of correction will be described with reference to FIGS. As shown in FIG. 5A, the operation of the ball screw nut 2 includes moving the ball screw nut 2 in the axial direction by rotating the screw shaft 1, and as shown in FIG. 5B. There is an operation of moving the ball screw nut 2 in the axial direction by rotating the ball screw nut 2. The operation of the support nut 44 includes the operation shown in FIG. 5 (A) and the operation shown in FIG. 5 (B), like the ball screw nut 2.
　図６（１）に示すように、ねじ軸１を回転させると、図５（Ａ）の原理により、ボールねじナット２及びサポート用ナット４４がねじ軸１の軸方向（図６（１）の右方向）に移動する。上述したように、サポート用ナット４４の速度は、ボールねじナット２の１／２である。 As shown in FIG. 6A, when the screw shaft 1 is rotated, the ball screw nut 2 and the support nut 44 are moved in the axial direction of the screw shaft 1 according to the principle of FIG. Move to the right). As described above, the speed of the support nut 44 is 1/2 that of the ball screw nut 2.
　図６（２）に示すように、ねじ軸１の軸方向への中間サポート４ａの移動が規制されたとき、すなわち中間サポート４ａがストッパ８ａに当たったとき、サポート用ナット４４がねじ軸１の回転方向とは逆方向に回転すれば、図５（Ｂ）の原理により、中間サポート４ａが反対方向（図６（２）の左方向）に移動する。したがって、サポート用ナット４４が逆回転することで、中間サポート４ａの位置はストッパ８ａに当たった位置に保たれ、中間サポート４ａの位置を補正することができる。ここで、ストッパ８ａ，８ｂの位置を中間サポート４ａ，４ｂのストローク端に合わせれば、往復運動の度に中間サポート４ａ，４ｂの位置を補正することができる。 As shown in FIG. 6 (2), when the movement of the intermediate support 4a in the axial direction of the screw shaft 1 is restricted, that is, when the intermediate support 4a hits the stopper 8a, the support nut 44 is attached to the screw shaft 1. When rotating in the direction opposite to the rotation direction, the intermediate support 4a moves in the opposite direction (left direction in FIG. 6 (2)) according to the principle of FIG. 5 (B). Accordingly, when the support nut 44 rotates in the reverse direction, the position of the intermediate support 4a is maintained at the position where it hits the stopper 8a, and the position of the intermediate support 4a can be corrected. Here, if the positions of the stoppers 8a and 8b are matched with the stroke ends of the intermediate supports 4a and 4b, the positions of the intermediate supports 4a and 4b can be corrected each time the reciprocating motion is performed.
　サポート用ナット４４を回転させるためには、ハウジング４２に対するサポート用ナット４４の回転の抵抗Ｒ１（以下、単に抵抗Ｒ１という）を、ねじ軸１に対するサポート用ナット４４の回転の抵抗Ｒ４（サポート用ナット４４のボール５１がねじ軸１のボール転走溝１ａを「すべる」ことに起因する抵抗、以下単に抵抗Ｒ４という）よりも小さくする必要がある。この関係が逆だと、中間サポート４ａ，４ｂがストッパ８ａ，８ｂに当たったとき、サポート用ナット４４の回転の替わりに、サポート用ナット４４のボール５１がねじ軸１のボール転走溝１ａをすべり、ボール転走溝１ａに疵が付く。抵抗Ｒ１を抵抗Ｒ４よりも小さくするために、ハウジング４２とサポート用ナット４４との間にベアリング４５を介在させ、抵抗Ｒ１を小さくしている。抵抗Ｒ１は、ねじ軸１に対するサポート用ナット４４の回転の抵抗Ｒ２（サポート用ナット４４のボール５１がねじ軸１のボール転走溝１ａを「転がる」ことに起因する抵抗、以下単に抵抗Ｒ２という）よりも小さく設定される。 In order to rotate the support nut 44, the rotation resistance R1 of the support nut 44 relative to the housing 42 (hereinafter simply referred to as resistance R1) is set to be the resistance R4 of the rotation of the support nut 44 relative to the screw shaft 1 (support nut). 44 balls 51 need to be smaller than the resistance caused by “sliding” the ball rolling groove 1a of the screw shaft 1 (hereinafter simply referred to as resistance R4). If this relationship is reversed, when the intermediate supports 4a and 4b hit the stoppers 8a and 8b, the balls 51 of the support nuts 44 instead of rotating the support nuts 44 are moved through the ball rolling grooves 1a of the screw shaft 1. Sliding and wrinkles on the ball rolling groove 1a. In order to make the resistance R1 smaller than the resistance R4, a bearing 45 is interposed between the housing 42 and the support nut 44 to reduce the resistance R1. The resistance R1 is a resistance R2 of rotation of the support nut 44 with respect to the screw shaft 1 (a resistance caused by the ball 51 of the support nut 44 "rolling" in the ball rolling groove 1a of the screw shaft 1, hereinafter simply referred to as a resistance R2). ) Is set smaller.
　ただし、抵抗Ｒ１が抵抗Ｒ２よりも小さいと、ねじ軸１を回転させても、サポート用ナット４４が回転するだけで、サポート用ナット４４はねじ軸１の軸方向に移動しない。これを避けるために、ハウジング４２には、サポート用ナット４４を所定圧で押す接触部材４６が設けられる。接触部材４６の圧力は、ハウジング４２に対するサポート用ナット４４の回転の抵抗Ｒ３（接触部材４６によって回転を規制されたサポート用ナット４４がハウジング４２に対して回転し始めるときの抵抗、以下単に抵抗Ｒ３という）が、抵抗Ｒ２よりも大きくなるように設定される。 However, if the resistance R1 is smaller than the resistance R2, even if the screw shaft 1 is rotated, only the support nut 44 rotates, and the support nut 44 does not move in the axial direction of the screw shaft 1. In order to avoid this, the housing 42 is provided with a contact member 46 that pushes the support nut 44 with a predetermined pressure. The pressure of the contact member 46 is the resistance R3 of the rotation of the support nut 44 against the housing 42 (the resistance when the support nut 44 whose rotation is restricted by the contact member 46 starts to rotate with respect to the housing 42, hereinafter simply the resistance R3. Is set to be larger than the resistance R2.
　ただし、接触部材４６の圧力の過大であると、抵抗Ｒ３が抵抗Ｒ４よりも大きくなる。この場合、中間サポート４ａ，４ｂがストッパ８ａ，８ｂに当たったとき、サポート用ナット４４のボール５１がねじ軸１のボール転走溝１ａをすべり、ボール転走溝１ａに疵が付く。これを避けるために、接触部材４６の圧力は、抵抗Ｒ３が抵抗Ｒ４よりも小さくなるように設定される。このように接触部材４６の圧力を設定すれば、中間サポート４ａ，４ｂがストッパ８ａ，８ｂに当たったとき、サポート用ナット４４が接触部材４６に対してすべりながら回転する。結局、抵抗Ｒ１～Ｒ４には、Ｒ１＜Ｒ２＜Ｒ３＜Ｒ４の関係があればよい。 However, if the pressure of the contact member 46 is excessive, the resistance R3 becomes larger than the resistance R4. In this case, when the intermediate supports 4a and 4b hit the stoppers 8a and 8b, the ball 51 of the support nut 44 slides on the ball rolling groove 1a of the screw shaft 1, and the ball rolling groove 1a is wrinkled. In order to avoid this, the pressure of the contact member 46 is set so that the resistance R3 is smaller than the resistance R4. If the pressure of the contact member 46 is set in this manner, the support nut 44 rotates while sliding against the contact member 46 when the intermediate supports 4a and 4b hit the stoppers 8a and 8b. As a result, the resistors R1 to R4 need only have a relationship of R1 <R2 <R3 <R4.
　本実施形態のアクチュエータによれば、サポート用ナット４４の外周に、ハウジング４２に対するサポート用ナット４４の回転の抵抗を小さくするベアリング４５を配置するので、抵抗Ｒ１を抵抗Ｒ４よりも小さくすることができる。このため、ねじ軸１の軸方向に移動する中間サポート４ａ，４ｂがストッパ８ａ，８ｂ等の物体に当たったとき、サポート用ナット４４を確実に回転させることができる。 According to the actuator of the present embodiment, since the bearing 45 that reduces the resistance of rotation of the support nut 44 relative to the housing 42 is disposed on the outer periphery of the support nut 44, the resistance R1 can be made smaller than the resistance R4. . For this reason, when the intermediate supports 4a and 4b moving in the axial direction of the screw shaft 1 hit an object such as the stoppers 8a and 8b, the support nut 44 can be reliably rotated.
　また、サポート用ナット４４の外周をラジアル荷重を負荷できるベアリング４５で回転可能に支持し、サポート用ナット４４の外周に接触部材４６を押圧するので、ハウジング４２に対するサポート用ナット４４の回転の抵抗Ｒ３の微調整が可能になる。さらに、接触部材４６を樹脂製にすることで、より抵抗Ｒ３の微調整が可能になる。 Further, since the outer periphery of the support nut 44 is rotatably supported by a bearing 45 capable of applying a radial load, and the contact member 46 is pressed against the outer periphery of the support nut 44, the resistance R3 of the rotation of the support nut 44 relative to the housing 42 Can be finely adjusted. Furthermore, the resistance R3 can be finely adjusted by making the contact member 46 made of resin.
　図７及び図８は、サポート用ナット４４の他の例を示す。図７は、ねじ軸１に組み付けられたサポート用ナット５４の断面図を示し、図８は、サポート用ナット５４の分解斜視図を示す。この例のサポート用ナット５４は、環状溝５２ａを有するナット本体５２と、サポート用ナット５４のボール５５を保持する保持器５６と、ナット本体５２に対して保持器５６が回転するのを案内するベアリング５７と、を備える。 7 and 8 show another example of the support nut 44. 7 shows a cross-sectional view of the support nut 54 assembled to the screw shaft 1, and FIG. 8 shows an exploded perspective view of the support nut 54. The support nut 54 in this example guides the rotation of the retainer 56 relative to the nut body 52, the retainer 56 that holds the ball 55 of the support nut 54, and the nut body 52 having the annular groove 52 a. And a bearing 57.
　ナット本体５２は円筒形に形成される。ナット本体５２の内周面には、リードが０の三条の環状溝５２ａが形成される。この実施形態のねじ軸１のボール転走溝１ａの条数は１である。合計三条の環状溝５２ａは一条のボール転走溝１ａと合計三つの交点を持つ。三つの交点には、三つのボール５５が配置される。ねじ軸１の軸方向からみて、三つのボール５５は周方向に均等間隔を空けて配置される。保持器５６は円筒形である。保持器５６には、ボール５５が配置される位置に合計三つの孔５６ａが開けられる。ナット本体５２の軸方向の両端部には、ベアリング５７が収容される。ベアリング５７は、ナット本体５２と保持器５６との間に介在し、保持器５６が回転するのを案内する。 The nut body 52 is formed in a cylindrical shape. On the inner peripheral surface of the nut main body 52, a three-row annular groove 52a having zero leads is formed. The number of the ball rolling grooves 1a of the screw shaft 1 of this embodiment is one. A total of three annular grooves 52a have a total of three intersections with a single ball rolling groove 1a. Three balls 55 are arranged at the three intersections. When viewed from the axial direction of the screw shaft 1, the three balls 55 are arranged at equal intervals in the circumferential direction. The retainer 56 is cylindrical. A total of three holes 56a are opened in the cage 56 at the positions where the balls 55 are arranged. Bearings 57 are accommodated at both ends of the nut body 52 in the axial direction. The bearing 57 is interposed between the nut main body 52 and the retainer 56 and guides the retainer 56 from rotating.
　この例のサポート用ナット４４によれば、保持器５６でボール５５を所定の位置に保持するので、ボール５５を円滑に移動させることができる。また、保持器５６をベアリング５７で回転可能に案内するので、保持器５６のすべり摩擦を解消することができる。さらに、ねじ軸１の軸方向から見て、サポート用ナット４４のボール５５が円周方向に均等間隔を空けて配置されるので、ねじ軸１に対して斜めにサポート用ナット４４が組み付けられるのを防止できる。 According to the support nut 44 of this example, since the ball 55 is held at a predetermined position by the cage 56, the ball 55 can be moved smoothly. Further, since the cage 56 is guided rotatably by the bearing 57, the sliding friction of the cage 56 can be eliminated. Further, since the balls 55 of the support nut 44 are arranged at equal intervals in the circumferential direction when viewed from the axial direction of the screw shaft 1, the support nut 44 is assembled obliquely with respect to the screw shaft 1. Can be prevented.
　図９は、本発明の第二の実施形態のアクチュエータの平面図を示す。この実施形態では、ボールねじナット２を案内する案内部、中間サポート４ａ，４ｂを案内する案内部の構成が、第一の実施形態のアクチェータと異なる。 FIG. 9 shows a plan view of the actuator according to the second embodiment of the present invention. In this embodiment, the structure of the guide part which guides the ball screw nut 2 and the guide part which guides intermediate | middle support 4a, 4b differs from the actuator of 1st embodiment.
　この実施形態では、ボールねじナット２を案内する案内部として、二本のレール６１ａ及び二つの移動ブロック６１ｂを用いている。二つの移動ブロック６１ｂ間には、テーブル６２が架け渡されている。ボールねじナット２はテーブル６２に結合される。ねじ軸１、ボールねじナット２の構造は、第一の実施形態のアクチュエータと同一なので、同一の符号を附してその説明を省略する。 In this embodiment, two rails 61a and two moving blocks 61b are used as a guide portion for guiding the ball screw nut 2. A table 62 is bridged between the two moving blocks 61b. The ball screw nut 2 is coupled to the table 62. Since the structure of the screw shaft 1 and the ball screw nut 2 is the same as that of the actuator of the first embodiment, the same reference numerals are given and description thereof is omitted.
　この実施形態では、中間サポート４ａ，４ｂを案内する案内部として、ベース６３を走行する車輪６４ａ，６４ｂが用いられる、車輪６４ａ，６４ｂは、中間サポート４ａ，４ｂに回転可能に取り付けられる。中間サポート４ａ，４ｂの回転を制限できるものであれば、この実施形態のように、案内部を車輪６４ａ，６４ｂから構成することもできる。 In this embodiment, wheels 64a and 64b traveling on the base 63 are used as guide portions for guiding the intermediate supports 4a and 4b. The wheels 64a and 64b are rotatably attached to the intermediate supports 4a and 4b. As long as the rotation of the intermediate supports 4a and 4b can be restricted, the guide portion can also be constituted by the wheels 64a and 64b as in this embodiment.
　なお、本発明は上記実施形態に限られることはなく、本発明の要旨を変更しない範囲で様々な実施形態に具現化することができる。 It should be noted that the present invention is not limited to the above embodiment, and can be embodied in various embodiments without departing from the spirit of the present invention.
　上記実施形態では、中間サポートを支持部の手前のストッパに当てているが、支持部に当てることもできる。また、中間サポートをボールねじナットのハウジングに当てることもできるし、中間サポートの移動ブロックとボールねじナットの移動ブロックとを当てることもできる。 In the above embodiment, the intermediate support is applied to the stopper in front of the support portion, but it can also be applied to the support portion. Further, the intermediate support can be applied to the ball screw nut housing, or the intermediate support moving block and the ball screw nut moving block can be applied.
　上記実施形態では、案内部としてリニアガイド、車輪を用いているが、ボールねじナット又はサポート用ナットの直線運動を許容しつつ回転を制限するものであれば、スプライン、ブッシュ等を用いることもできる。 In the above embodiment, a linear guide and a wheel are used as the guide portion. However, a spline, a bush, or the like can be used as long as it restricts rotation while allowing linear motion of the ball screw nut or the support nut. .
　上記実施形態では、サポート用ナットとベアリングとを別体にしているが、サポート用ナットとベアリングの内輪とを一体にすることもできる。 In the above embodiment, the support nut and the bearing are separated, but the support nut and the inner ring of the bearing can be integrated.
　本明細書は、２０１４年５月１５日出願の特願２０１４－１０１２０１に基づく。この内容はすべてここに含めておく。 This specification is based on Japanese Patent Application No. 2014-101201 filed on May 15, 2014. All this content is included here.
１…ねじ軸，１ａ…ボール転走溝（転動体転走溝），２…ボールねじナット（ナット），４ａ，４ｂ…中間サポート，８ａ，８ｂ…ストッパ（物体），１１…リニアガイド（案内部），１２…リニアガイド（案内部），４２…ハウジング，４２ａ…収容孔，４２ｂ…貫通孔，４２ｃ…凹部，４４…サポート用ナット，４４ａ…環状溝，４５…ベアリング（転がり支持部），４６…接触部材，４９…抵抗調整部，５１…ボール（転動体），５２…ナット本体，５２ａ…環状溝，５４…サポート用ナット，５５…ボール，５６…保持器，５７…ベアリング
  DESCRIPTION OF SYMBOLS 1 ... Screw shaft, 1a ... Ball rolling groove (rolling body rolling groove), 2 ... Ball screw nut (nut), 4a, 4b ... Intermediate support, 8a, 8b ... Stopper (object), 11 ... Linear guide (Guide) Part), 12 ... linear guide (guide part), 42 ... housing, 42a ... accommodation hole, 42b ... through hole, 42c ... recess, 44 ... support nut, 44a ... annular groove, 45 ... bearing (rolling support part), 46 ... contact member, 49 ... resistance adjusting portion, 51 ... ball (rolling element), 52 ... nut body, 52a ... annular groove, 54 ... nut for support, 55 ... ball, 56 ... cage, 57 ... bearing

Claims (5)

  1. 　ねじ軸と、前記ねじ軸に転動体を介して組み付けられるナットと、前記ナットと前記ねじ軸の軸方向の端部との間に配置される中間サポートと、を備え、前記ねじ軸を回転駆動させることによって、前記ナット及び前記中間サポートを前記ねじ軸の軸方向に移動させるアクチュエータにおいて、
    　前記中間サポートは、
    　前記ねじ軸の回転に応じて前記ねじ軸の軸方向に移動し、前記ねじ軸との間に転動体が介在されるサポート用ナットと、
    　前記サポート用ナットが収容されるハウジングと、
    　前記サポート用ナットの外周に配置され、前記ハウジングに対して前記サポート用ナットを回転可能に支持する転がり支持部と、
    　前記サポート用ナットの外周に接して、前記ハウジングに対する前記サポート用ナットの回転を規制すると共に、前記ねじ軸の軸方向への前記中間サポートの移動が規制されたとき、前記ハウジングに対して前記サポート用ナットが回転できるようにする抵抗調整部と、を備えるアクチュエータ。     A screw shaft; a nut that is assembled to the screw shaft via a rolling element; and an intermediate support that is disposed between the nut and the axial end of the screw shaft. In the actuator that moves the nut and the intermediate support in the axial direction of the screw shaft,
    The intermediate support is
    A nut for support that moves in the axial direction of the screw shaft according to the rotation of the screw shaft, and a rolling element is interposed between the screw shaft,
    A housing that accommodates the support nut;
    A rolling support portion disposed on an outer periphery of the support nut and rotatably supporting the support nut with respect to the housing;
    In contact with the outer periphery of the support nut, the rotation of the support nut with respect to the housing is restricted, and when the movement of the intermediate support in the axial direction of the screw shaft is restricted, the support with respect to the housing An actuator including a resistance adjusting portion that allows the nut to rotate.
  2. 　前記転がり支持部は、前記サポート用ナットの外周に一体又は別体に設けられ、ラジアル荷重を負荷できるベアリングであり、
    　前記抵抗調整部は、前記ハウジングから前記サポート用ナットの外周に向けて押圧される接触部材を備えることを特徴とする請求項１に記載のアクチュエータ。     The rolling support part is a bearing that is provided integrally or separately on the outer periphery of the support nut, and is capable of applying a radial load.
    The actuator according to claim 1, wherein the resistance adjusting unit includes a contact member that is pressed from the housing toward an outer periphery of the support nut.
  3. 　前記サポート用ナットは、内周面にリードが０又はその近傍の環状溝を有し、
    　前記転動体は、前記サポート用ナットの前記環状溝と前記ねじ軸の転動体転走溝との交点に配置されることを特徴とする請求項２に記載のアクチュエータ。     The support nut has an annular groove on the inner peripheral surface where the lead is 0 or in the vicinity thereof,
    The actuator according to claim 2, wherein the rolling element is disposed at an intersection between the annular groove of the support nut and the rolling element rolling groove of the screw shaft.
  4. 　前記サポート用ナットは、
    　前記環状溝を有するナット本体と、
    　前記サポート用ナットの前記転動体を保持する保持器と、
    　前記ナット本体に対して前記保持器が回転するのを案内するベアリングと、を備えることを特徴とする請求項１ないし３のいずれかに記載のアクチュエータ。     The support nut is
    A nut body having the annular groove;
    A cage for holding the rolling elements of the support nut;
    The actuator according to any one of claims 1 to 3, further comprising a bearing that guides rotation of the cage with respect to the nut body.
  5. 　前記ハウジングに対する前記サポート用ナットの回転の抵抗をＲ１、
    　前記サポート用ナットの前記転動体が前記ねじ軸の前記転動体転走溝を転がるときの、前記ねじ軸に対する前記サポート用ナットの回転の抵抗をＲ２、
    　前記抵抗調整部によって回転を規制された前記サポート用ナットが前記ハウジングに対して回転し始めるときの、前記ハウジングに対する前記サポート用ナットの回転の抵抗をＲ３、
    　前記サポート用ナットの前記転動体が前記ねじ軸の前記転動体転走溝をすべるときの、前記ねじ軸に対する前記サポート用ナットの回転の抵抗をＲ４とするとき、
    　Ｒ１＜Ｒ２＜Ｒ３＜Ｒ４の関係があることを特徴とする請求項１ないし４のいずれかに記載のアクチュエータ。     R1 is a resistance of rotation of the support nut relative to the housing.
    When the rolling element of the support nut rolls the rolling element rolling groove of the screw shaft, the resistance of rotation of the support nut with respect to the screw shaft is R2,
    The resistance of rotation of the support nut relative to the housing when the support nut whose rotation is restricted by the resistance adjusting portion starts to rotate relative to the housing is R3,
    When the rolling resistance of the support nut relative to the screw shaft when the rolling element of the support nut slides on the rolling element rolling groove of the screw shaft is R4,
    5. The actuator according to claim 1, wherein a relationship of R1 <R2 <R3 <R4 is established.
PCT/JP2015/064004 2014-05-15 2015-05-15 Actuator WO2015174516A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112879517A (en) * 2021-01-20 2021-06-01 北京精密机电控制设备研究所 Lead screw supporting and limiting structure

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0369843A (en) * 1989-08-04 1991-03-26 Bo Granbom Support nut
JPH0529652U (en) * 1991-09-30 1993-04-20 日本精工株式会社 Intermediate support device for screw shaft
JP2001099260A (en) * 1999-09-29 2001-04-10 Nsk Ltd Intermediate support for ball screw device
JP2001205538A (en) * 2000-01-28 2001-07-31 Toshiba Mach Co Ltd Mounting structure of mover to feed drive system of machine tool

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0369843A (en) * 1989-08-04 1991-03-26 Bo Granbom Support nut
JPH0529652U (en) * 1991-09-30 1993-04-20 日本精工株式会社 Intermediate support device for screw shaft
JP2001099260A (en) * 1999-09-29 2001-04-10 Nsk Ltd Intermediate support for ball screw device
JP2001205538A (en) * 2000-01-28 2001-07-31 Toshiba Mach Co Ltd Mounting structure of mover to feed drive system of machine tool

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112879517A (en) * 2021-01-20 2021-06-01 北京精密机电控制设备研究所 Lead screw supporting and limiting structure

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