JP2007247682A - Reduction gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction gear that includes an eccentric rotor rotating together with a motor shaft, an external tooth gear supported pivotally at the outer periphery of the eccentric rotor, an internal tooth gear fixed and arranged while meshing with the external tooth gear, an output member arranged coaxially with the motor shaft, and an Oldham's mechanism provided between the external tooth gear and the output member to transmit only rotation component of the external tooth gear to thereby eliminate play in the Oldham's mechanism and prevent the occurrence of axial deviation. <P>SOLUTION: The Oldham's mechanism 60 is composed of a plurality of pins 68 fixed in either of the external tooth gear 57 and the output member 59 and protruding onto the other side, a plurality of connection holes 69 formed to have larger diameter than that of the pin 68 at positions corresponding to these pins 68, being eccentric to the pins 68, and provided in either of the eccentric rotor 56 and the output member 59, and a plurality of eccentric rolling bearings 70 provided among the outer peripheries of each pin 68 and the inner peripheries of each connection hole 69 by bringing their inner peripheries and outer peripheries into contact with the outer peripheries of each pin 68 and the inner peripheries of each connection hole 69, respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes an eccentric rotator that has an axis that is eccentric from the axis of a motor shaft included in the electric motor, and that rotates together with the motor shaft, and that has the same axis as the eccentric rotator and is rotatable on the outer periphery of the eccentric rotator. An external gear provided with external teeth on the outer periphery and a larger number of internal teeth than the external teeth provided on the inner periphery so as to mesh with the external teeth and coaxial with the motor shaft An internal gear fixedly arranged, an output member having an axis coaxial with the motor shaft, and an Oldham mechanism provided between the external gear and the output member so as to transmit only the rotation component of the external gear. It is related with a reduction gear provided.

Such a reduction gear is already known from Patent Document 1, for example.
JP-A-6-294449

  However, in the Oldham mechanism disclosed in Patent Document 1, a plurality of pins provided on the external gear are merely loosely fitted in connection holes provided on the output member, respectively. There is a possibility that a play in the circumferential direction will occur and an axial deviation will occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a speed reducer that eliminates play in the Oldham mechanism and prevents axial misalignment.

  To achieve the above object, the present invention provides an eccentric rotating body that has an axis that is eccentric from an axis of a motor shaft included in an electric motor and that rotates together with the motor shaft, and that has the same axis as the eccentric rotating body. An external gear that is rotatably supported on the outer periphery of the eccentric rotating body and has external teeth on the outer periphery, and a larger number of internal teeth than the external teeth are provided on the inner periphery so as to mesh with the external teeth. And an external gear fixedly arranged coaxially with the motor shaft, an output member having an axis coaxial with the motor shaft, and the external gear and the external gear so as to transmit only the rotation component of the external gear. An Oldham mechanism provided between output members, wherein the Oldham mechanism includes a plurality of pins fixed to one of the external gear and the output member and projecting to the other side, and the pins. And a plurality of connecting holes provided in the other of the eccentric rotating body and the output member that are eccentric with respect to the pins, and are arranged at positions corresponding to the pins, and the outer circumferences of the pins and the connecting holes. The inner periphery and the outer periphery of the pin are in contact with each other, and a plurality of eccentric rolling bearings are interposed between the outer periphery of each of the pins and the inner periphery of each of the connection holes.

  According to the above configuration of the present invention, the inner periphery and the outer periphery of the eccentric rolling bearing interposed between the outer periphery of the plurality of pins and the inner periphery of the plurality of connection holes are the outer periphery of each pin and the inner periphery of each connection hole. Therefore, there is no circumferential play between the external gear and the output member, and therefore it is possible to reliably prevent shaft runout.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a vehicle disc brake using the speed reducer of the present invention. FIG. 3 is an enlarged cross-sectional view taken along line 3-3 in FIG. 1, FIG. 4 is an enlarged view of a portion indicated by arrow 4 in FIG. 1, FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. FIG.

  First, in FIG. 1 and FIG. 2, this vehicle disc brake can obtain a service brake state by hydraulic pressure and can be operated by the electric motor 11 to obtain a service brake state and a parking brake state. A pair of frictions disposed between the disk rotor 12 and the caliper body 13 so as to be opposed to both side surfaces of the disk rotor 12, the caliper body 13, and the disk rotor 12 rotating together with a wheel of a wheel (not shown). Pads 14 and 15 are provided.

  The caliper body 13 includes a working portion 13a supported by a bracket 16 attached to the vehicle body so as to be slidable in a direction along the axis of the disc rotor 12, and a reaction that sandwiches the disc rotor 12 between the working portion 13a. The portion 13 b is integrally connected by a bridge portion 13 c that straddles the disk rotor 12.

  The friction pad 14 facing one side of the disk rotor 12 on the side of the action part 13a is provided with a lining 17 that can slide and come into contact with the disk rotor 12 to exert a frictional force, and the disk 18 on the side of the reaction part 13b. The friction pad 15 facing the other side of the rotor 12 is formed by providing a lining 19 on the back metal 20 that can slide and contact the disk rotor 12 to exert a frictional force. As clearly shown in FIG. 2, the back metal 18 of the friction pad 14 is provided with ears 18 a, 18 a protruding from both ends along the circumferential direction of the disk rotor 12, and these ears 18 a. The holding grooves 16a and 16a provided are fitted so as to be able to move in the direction along the axis of the disk rotor 12. That is, the friction pad 14 can be moved in the direction along the axis of the disk rotor 12 and is held by the bracket 16. The friction pad 15 is also held by the bracket 16 with the same holding structure as the friction pad 14. It is possible to move in the direction along the axis of the disk rotor 12.

  A cylinder hole 21, which has an axis parallel to the axis of the disk rotor 12 and opens to the disk rotor 12 side and is closed by an end wall 22 on the side opposite to the disk rotor 12, is provided in the action portion 13 a of the caliper body 13. Are provided so as to have a circular cross-sectional shape, and a through hole 23 coaxial with the cylinder hole 21 is provided in the center of the end wall 22.

  The cylinder hole 21 has a brake fluid pressure chamber 24 formed between the end wall 22 and a brake piston 25 formed in a bottomed cylindrical shape having a closed portion 25a at the front end on the disk rotor 12 side. The front end closing portion 25a is slidably accommodated in the axial direction so as to contact the back metal 18 of the friction pad 14, and the front end closing portion 25a of the brake piston 25 prevents rotation in the cylinder hole 21. In order to do so, the back metal 18 is engaged.

  An annular piston seal 26 interposed between the caliper body 13 and the brake piston 25 is mounted on the inner surface of the cylinder hole 21, and an annular dust boot 27 is provided between the opening end of the cylinder hole 21 and the brake piston 25. And a hydraulic pressure path 28 for guiding the hydraulic pressure to the brake hydraulic pressure chamber 24 is provided in the action portion 13a.

  By the way, the brake piston 25 has an output of the electric motor 11 that exerts power for moving the friction pads 14 and 15 forward and backward with respect to the disk rotor 12, a speed reducer 32 that decelerates the output, and a rotation of the speed reducer 32. The output is transmitted via a screw mechanism 33 that is a motion conversion mechanism that converts the axial movement of the brake piston 25 into a forward / backward movement force, and the screw mechanism 33 is disposed behind the brake piston 25. The electric motor 11 is accommodated in the action part 13a of the caliper body 13 on the side opposite to the disk rotor 12, and the speed reducer 32 is attached to a speed reducer case 34 attached to the action part 13a. Be contained.

  Referring also to FIG. 3, the screw mechanism 33 includes a screw shaft 35 that is coaxial with the cylinder hole 21, and a nut 36 that is engaged with the brake piston 25 and is screwed into the screw shaft 35 while being relatively unable to rotate. The through-hole 23 of the end wall 22 is rotatable so as to transmit the rotational power of the electric motor 11 decelerated by the speed reducer 32 to the rear end of the screw shaft 35 on the side opposite to the brake piston 25. A transmission rotation shaft 37 that penetrates is coaxially and integrally connected, and an O-ring 38 is interposed between the end wall 22 and the transmission rotation shaft 37. In the brake fluid pressure chamber 24, the transmission rotating shaft 37 is sandwiched between an annular step portion 37 a provided on the transmission rotating shaft 37 and a retaining ring 31 attached to the transmission rotating shaft 37. A flange 40 is fixed, and a thrust bearing 39 is interposed between the flange 40 and the end wall 22.

  The screw shaft 35 is screwed into a nut 36 surrounding the screw shaft 35 in the brake piston 25. The nut 36 has an engagement portion 36 a having a regular square outer periphery at the front end, and the front end surface of the engagement portion 36 a abuts the front end inner surface of the brake piston 25.

  On the other hand, on the inner periphery of the brake piston 25 having a bottomed cylindrical shape, there are locking grooves 42 that are integral multiples (twice in this embodiment) of the number of the four corners 41 of the engaging portion 36a. The corner portions 41 are selectively engaged at a plurality of locations whose phases are shifted in the circumferential direction, and are provided at equal intervals in the circumferential direction while extending in the axial direction. That is, the inner periphery of the brake piston 25 is formed in a shape corresponding to the outer periphery shape of the engaging portion 36a and a plurality of regular polygons whose phases are shifted from each other. In this embodiment, the phase is 45. It is formed in a star shape with two regular squares that are offset.

  Accordingly, the engaging groove 42 on the inner periphery of the brake piston 25, which cannot be rotated, has a simple structure in which each corner 41 of the engaging portion 36a provided on the nut 36 is engaged with the outer periphery as a regular polygon. The nut 36 can be made non-rotatable. In addition, the engaging grooves 36a are provided with locking grooves 42, which are an integral multiple of the number of corners 41, of the engaging portion 36a, on the inner periphery of the brake piston 25, and when the engaging portion 36a is engaged with the brake piston 25. Can be easily aligned, and the assemblability can be improved. Further, the air release performance is enhanced by the locking grooves 42 in which the engaging portions 36a are not locked.

  In such a screw mechanism 33, when the power from the electric motor 11 is decelerated by the speed reducer 32 and the power rotating in one direction is transmitted to the screw shaft 35 via the transmission rotating shaft 37, the brake piston 25 and The disc rotor 12 is clamped from both sides by the friction pads 14 and 15 due to the action and the reaction caused by the brake piston 25 sliding forward in the axial direction in a state in which the rotation of the nut 36 is prevented, thereby obtaining a braking force. become. Further, when the screw shaft 35 is rotated in the other direction, the brake piston 25 slides rearward in the axial direction to release the braking state.

  Referring again to FIG. 1, the speed reducer case 34 is composed of an action part 13a in the caliper body 13 and a motor case 52 of the electric motor 11, and the motor case 52 is composed of a plurality of bolts 53. To be concluded. In addition, the motor shaft 55 provided in the electric motor 11 is disposed coaxially with the rotation axis of the screw mechanism 33, that is, the axis of the transmission rotation shaft 37 in a state where the motor case 52 is fastened to the action portion 13 a. The motor case 52 is provided with an annular seal member 51 that elastically contacts the action portion 13a.

  The speed reducer case 34 forms a speed reducer chamber 54 that is isolated from the brake fluid pressure chamber 24 in the action portion 13 a of the caliper body 13 by the end wall 22. A reduction gear 32 is accommodated.

  4 to 6, the speed reducer 32 has an eccentric rotator 56 that has an outer periphery that is eccentric from the axis of the motor shaft 55 of the electric motor 11, and rotates together with the motor shaft 55. An external gear 57 having the same axis as the rotary body 56 and rotatably supported on the outer periphery of the eccentric rotary body 56, an internal gear 58, and the motor shaft 55 are arranged coaxially with the screw mechanism. 33, an output member 59 coupled to the transmission gear 33 through the transmission rotation shaft 37, and an Oldham mechanism 60 provided between the external gear 57 and the output member 59 so as to transmit only the rotation component of the external gear 57. Is provided.

  The eccentric rotator 56 is formed integrally with the motor shaft 55 such that the center C2 is disposed at a position shifted from the axis C1 of the motor shaft 55 by the amount of eccentricity ε. The shaft 55 is eccentric by an eccentric amount ε.

  The external gear 57 is pivotally supported on the eccentric rotator 56 via a ball bearing 61 between the outer periphery of the eccentric rotator 56, and a plurality of external teeth 62, 62 are provided on the outer periphery of the external gear 57. ... are provided. The internal gear 58 is fixed to the speed reducer case 34 so as to be sandwiched between the action portion 13a of the caliper body 13 and the motor case 52. The number of internal teeth 63, 63... Larger than the number of external teeth 62, 62... Is provided so as to mesh with the external teeth 62, 62. For example, one is set more than the number of 62, 62.

  The output member 59 includes a disc portion 59a facing the external gear 57 on the side opposite to the electric motor 11, and the electric motor 11 connected to the inner periphery of the disc portion 59a at a right angle and integrally. The connecting cylindrical part 59b extending to the opposite side and the flange part 59c projecting radially inward from the end of the connecting cylindrical part 59b opposite to the electric motor 11 are integrally formed. A ball bearing 64 is interposed between 59b and the motor shaft 55, and a ball bearing 65 is interposed between the action portion 13a of the caliper body 13 and the connecting cylindrical portion 59b in the speed reducer case 34. Moreover, the inner periphery of the flange portion 59c is integrally connected to the transmission rotation shaft 37, and the output member 59, the transmission rotation shaft 37, and the screw shaft 35 are integrally formed.

  Further, the Oldham mechanism 60 has a plurality of, for example, four pieces, which are fitted and fixed to the external gear 57 at equal intervals in the circumferential direction on the first virtual circle SC1 with the axis of the external gear 57 as the center. Pins 68 are provided on the disk portion 59a of the output member 59 at equal intervals in the circumferential direction on the second virtual circle SC2 centered on the axis of the motor shaft 55. The inner periphery and the outer periphery are brought into contact with a plurality of connecting holes 69 formed to have a diameter larger than the diameter and eccentric from each pin 68, and the outer periphery of each pin 68 and the inner periphery of each connecting hole 69. The eccentric rolling bearings 70 are respectively interposed between the outer periphery of the pins 68 and the inner periphery of the connection holes 69.

  Next, the operation of this embodiment will be described. The speed reducer 32 that decelerates the rotational power of the electric motor 11 has an outer periphery that is eccentric from the axis of the motor shaft 55 provided in the electric motor 11 and rotates together with the motor shaft 55. And an external gear 57 having the same axis as the eccentric rotator 56 and rotatably supported on the outer periphery of the eccentric rotator 56 and provided with a plurality of external teeth 62. A larger number of internal teeth 63 than the number of external teeth 62 are provided on the inner periphery so as to mesh with the external teeth 62 and are arranged coaxially with the motor shaft 55; An output member 59 arranged coaxially with the motor shaft 55 and connected to the screw mechanism 33, and an Oldham mechanism 60 provided between the external gear 57 and the output member 59 so as to transmit only the rotation component of the external gear 57. Are those comprising, internal gear 58 is fixed to the reducer case 34 disposed to the caliper body 13 houses a reduction gear 32.

  According to such a reduction gear 32, the external gear 57 corresponds to the number of internal teeth 63 of the internal gear 58 and the external gear 57 according to the rotation of the eccentric rotating body 56 due to the rotation operation of the electric motor 11. The motor rotates with a reduction ratio corresponding to the difference in the number of external teeth 62..., And the rotation component of the external gear 57 is input to the screw mechanism 33 via the Oldham mechanism 60 and the brake piston 25 is driven in the axial direction. Will be. In addition, since the internal gear 58 of the speed reducer 32 is fixedly arranged and there is no need to secure a space for arranging ball bearings or the like radially outward of the external gear 57, the speed reducer 32 can be made compact. It becomes possible.

  The Oldham mechanism 60 includes a plurality of pins 68 provided on the external gear 57 at equal intervals in the circumferential direction on the first virtual circle SC1 with the axis of the external gear 57 as the center, and a motor shaft. The output member 59 is provided at a position at equal intervals in the circumferential direction on the second imaginary circle SC2 with the axis of 55 as the center, and is formed to have a diameter larger than the diameter of each pin 68. Is a plurality of eccentric connecting holes 69, and the outer periphery of each pin 68 and the inner periphery of each connecting hole 69 are brought into contact with the inner periphery and the outer periphery so that the outer periphery of each pin 68 and the inner periphery of each connecting hole 69. Are formed with eccentric rolling bearings 70... Interposed between them, so that there is no circumferential play between the external gear 57 and the output member 59, and therefore it is possible to reliably prevent shaft runout. be able to.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, the external gear 57 is provided with the pins 68... And the output member 59 is provided with the connection holes 69. However, conversely, the external gear 57 is provided with a connection hole. The output member 59 may be provided with a pin.

It is a longitudinal cross-sectional view of the disc brake for vehicles using the reduction gear of this invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is an enlarged view of a portion indicated by an arrow 4 in FIG. 1. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Electric motor 32 ... Reduction gear 55 ... Motor shaft 56 ... Eccentric rotating body 57 ... External gear 58 ... Internal gear 59 ... Output member 60 ... Oldham Mechanism 62 ... External teeth 63 ... Internal teeth 68 ... Pin 69 ... Connection hole 70 ... Eccentric rolling bearing

Claims (1)

  An eccentric rotator (56) having an axis decentered from the axis of the motor shaft (55) provided in the electric motor (11) and rotating with the motor shaft (55), and having the same axis as the eccentric rotator (56) An external gear (57) rotatably supported on the outer periphery of the eccentric rotating body (56) and provided with external teeth (62) on the outer periphery, and a larger number of internal gears than the external teeth (57). An internal gear (58) provided on the inner circumference with teeth (63) meshing with the external teeth (62) and fixedly arranged coaxially with the motor shaft (55), and the motor shaft (55) And an Oldham mechanism provided between the external gear (57) and the output member (59) so as to transmit only the rotation component of the external gear (57). (60) The Oldham mechanism (60) includes a plurality of pins (68) fixed to one of the external gear (57) and the output member (59) and protruding to the other side, and the pins (68). And a plurality of couplings provided on the other of the eccentric rotating body (56) and the output member (59) that are formed with a diameter larger than that of the pin (68) and eccentric with respect to the pin (68). An inner periphery and an outer periphery are brought into contact with a hole (69), an outer periphery of each pin (68) and an inner periphery of each connection hole (69), and the outer periphery of each pin (68) and each connection hole (69). A speed reducer comprising a plurality of eccentric rolling bearings (70) interposed between the inner peripheries of the motor.

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