WO2019044282A1

WO2019044282A1 - Power steering device

Info

Publication number: WO2019044282A1
Application number: PCT/JP2018/027744
Authority: WO
Inventors: 貴也柳生
Original assignee: Ｋｙｂ株式会社
Priority date: 2017-08-31
Filing date: 2018-07-24
Publication date: 2019-03-07
Also published as: JP6806649B2; JP2019043336A

Abstract

This power steering device (100) is provided with: a bearing (11) which rotatably supports the tip end side of a worm shaft (2); a gear case (3) for accommodating the worm shaft (2); and a holder (30) which is disposed in the gear case (3), and which accommodates the bearing (11). The holder (30) is provided with: a first holder (40) for holding the bearing (11); a second holder (60) provided with a guide part (62) for guiding movement of the bearing (11) towards a worm wheel (1); a spring (70) which is provided in a compressed state between the first holder (40) and the second holder (60); and a support part (50) which is provided to the first holder (40), and which supports the spring (70). The support part (50) is provided with: a first support part (51) which is capable of supporting the spring (70) such that an impelling force is exerted in a first impelling direction; and a second support part (52) which is capable of supporting the spring (70) such that an impelling force is exerted in a second impelling direction.

Description

Power steering device

The present invention relates to a power steering apparatus.

In JP2013-208933A, while both ends of a worm gear driven by an electric motor are pivotally supported by a bearing provided on a gear housing, a worm wheel meshing with the worm gear is fixed to a steering shaft, and a meshing portion between the worm gear and the worm wheel An electric power steering apparatus is disclosed which comprises preloading means for biasing the bearing of the worm gear in a predetermined preloading direction so as to apply a preload to the motor.

In this electric power steering apparatus, the worm gear is supported swingably around the bearing on one end side, and the bearing on the other end side is biased in a predetermined preload direction by the preload means. The preload means comprises a bearing case, a seat rubber and a spring. The cylindrical projection of the bearing case is loaded into a rubber loading hole provided in the gear housing, and a sheet rubber containing a spring is loaded into the rubber loading hole. In the preloading means, the preloading direction for biasing the bearing is the direction of the radial component of the driving reaction force received from the worm wheel when the worm gear rotates in the left steering direction, and the worm gear rotates in the right steering direction. It is set in the radial direction passing through the central axis of the worm gear within the range of the minor angle sandwiched by the direction of the radial component of the drive reaction force received from the worm wheel.

In the power steering apparatus, in order to reduce the manufacturing cost, it is required to share the configuration between the left-hand drive car and the right-hand drive car.

As described in JP2013-208933A, in a power steering apparatus provided with a mechanism that biases the worm shaft to reduce backlash, the twist directions of the worm gears differ between the left-hand drive car and the right-hand drive car. Therefore, the biasing directions of the springs for biasing the worm shaft are also different. Since the power steering device is configured to accommodate the spring in the hole formed in the gear case, in order to make the device configuration common to the left-hand drive car and the right-hand drive car, the power steering device is biased to the relatively large part gear case Processing such as forming holes according to the direction must be performed. Therefore, with this power steering apparatus, there is a possibility that the manufacturing cost will be increased.

The present invention aims to reduce the manufacturing cost of a power steering apparatus.

According to an aspect of the present invention, there is provided a power steering apparatus comprising: a worm shaft rotating with driving of an electric motor; a worm wheel meshing with the worm shaft; and a bearing rotatably supporting a distal end side of the worm shaft. A gear case for accommodating the worm shaft, and a holder disposed in the gear case for accommodating the bearing, the holder comprising: a first holder for holding the bearing; and a guide portion for guiding the movement of the bearing toward the worm wheel A second holder, an urging member provided in a compressed state between the first holder and the second holder, and a supporting portion provided on either the first holder or the second holder to support the urging member. The supporting portion is capable of supporting the biasing member so as to exert the biasing force in the first biasing direction, and a second biasing different from the first biasing direction And a second support portion capable of supporting the biasing member so as to exert a biasing force toward the other, wherein the biasing member is supported by either the first support portion or the second support portion. I assume.

FIG. 1 is a block diagram of a power steering apparatus according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a power steering apparatus according to the first embodiment of the present invention. FIG. 3 is a perspective view of the holder according to the first embodiment of the present invention. FIG. 4 is a front side perspective view of the first holder according to the first embodiment of the present invention. FIG. 5 is a rear perspective view of the first holder according to the first embodiment of the present invention. FIG. 6 is a front perspective view of the first holder and the bearing according to the first embodiment of the present invention. FIG. 7 is a front perspective view of the second holder according to the first embodiment of the present invention. FIG. 8 is a rear perspective view of the second holder according to the first embodiment of the present invention. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. FIG. 10 is a cross-sectional view taken along the line XX in FIG. FIG. 11 is a plan view of the clip according to the first embodiment of the present invention. FIG. 12 is a cross-sectional view showing a state in which the holder according to the first embodiment of the present invention is incorporated into the gear case. FIG. 13 is a perspective view for explaining the assembly procedure of the holder according to the first embodiment of the present invention, and shows the process of assembling the first holder, the bearing and the spring. FIG. 14 is a perspective view for explaining the assembly procedure of the holder according to the first embodiment of the present invention, and shows the process of assembling the second holder and the clip. FIG. 15 is a cross-sectional view showing a first modified example of the holder according to the first embodiment of the present invention. FIG. 16 is a cross-sectional view showing a second modified example of the holder according to the first embodiment of the present invention. FIG. 17 is a view showing a third modified example of the holder according to the first embodiment of the present invention, and is a plan view showing a modified example of the clip. FIG. 18 is a cross-sectional view showing a second holder according to the second embodiment of the present invention. FIG. 19 is a cross-sectional view showing a second holder and an elastic ring according to a second embodiment of the present invention. FIG. 20 is a front perspective view showing a holder according to a third embodiment of the present invention. FIG. 21 is a rear perspective view showing a holder according to a third embodiment of the present invention. FIG. 22 is a front perspective view showing a first holder according to a third embodiment of the present invention. FIG. 23 is a rear perspective view showing the first holder according to the third embodiment of the present invention. FIG. 24 is a front perspective view showing a second holder according to the third embodiment of the present invention. FIG. 25 is a rear perspective view showing a second holder according to the third embodiment of the present invention. FIG. 26 is a cross-sectional view showing a state in which the holder according to the third embodiment of the present invention is incorporated into the gear case.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
A power steering apparatus 100 according to a first embodiment of the present invention will be described with reference to FIGS.

The power steering device 100 is a device mounted on a vehicle and assisting a steering force that a driver applies to a steering wheel.

As shown in FIGS. 1 and 2, the power steering apparatus 100 meshes with the worm shaft 2 connected to the output shaft of the electric motor 7 and rotates with the driving of the electric motor 7, and rotates the wheel 6 And a worm wheel 1 for transmitting the rotational force of the electric motor 7 to the rack shaft 8 to be steered. As the electric motor 7 is driven, the worm shaft 2 is rotated, and the rotation of the worm shaft 2 is decelerated and transmitted to the worm wheel 1. The worm wheel 1 and the worm shaft 2 constitute a worm reduction gear.

As shown in FIG. 1, a steering shaft 20 is connected to the steering wheel 10, and the steering shaft 20 rotates with the rotation of the steering wheel 10. The steering shaft 20 includes an input shaft 21 linked to the steering wheel 10, an output shaft 22 linked to the rack shaft 8, and a torsion bar 23 linked the input shaft 21 and the output shaft 22. The worm wheel 1 is provided on the output shaft 22.

The power steering apparatus 100 includes a torque sensor 24 for detecting a steering torque acting on the torsion bar 23 by relative rotation between the input shaft 21 and the output shaft 22 accompanying a steering operation by the driver, and a steering detected by the torque sensor 24. And a controller 25 for controlling the drive of the electric motor 7 based on the torque. The torque output from the electric motor 7 is transmitted from the worm shaft 2 to the worm wheel 1 and applied to the output shaft 22 as an assist torque. As described above, the power steering apparatus 100 controls the drive of the electric motor 7 by the controller 25 based on the detection result of the torque sensor 24 to assist the driver's steering operation.

As shown in FIG. 2, the worm shaft 2 is accommodated in a metal gear case 3, and the electric motor 7 is attached to the gear case 3. The gear case 3 has a peripheral wall 3 b surrounding the worm shaft 2 and a bottom wall 3 c facing the tip of the worm shaft 2. The peripheral wall 3b and the bottom wall 3c are integrally formed. As described above, the gear case 3 does not have a configuration in which the opening 43 at the bottom is sealed with a lid, but has a bag-like structure, and thus has excellent waterproofness. The gear case 3 may be made of resin. The gear case 3 may have a structure in which the open end of the peripheral wall 3b is sealed with a lid, instead of the integral structure of the peripheral wall 3b and the bottom wall 3c.

A tooth portion 2 a that meshes with the tooth portion of the worm wheel 1 is formed on a part of the worm shaft 2. An opening 43 is formed in the peripheral wall 3b of the gear case 3 on the worm shaft 2 side at a position corresponding to the tooth 2a, and the tooth 2a of the worm shaft 2 and the tooth of the worm wheel 1 mesh with each other through the opening 43.

The proximal end side which is the electric motor 7 side of the worm shaft 2 is rotatably supported by the first bearing 4. The first bearing 4 is a ball bearing in which a ball is interposed between an annular inner ring and an outer ring. The outer ring of the first bearing 4 is held between a step 3 a formed in the gear case 3 and a lock nut 5 fastened in the gear case 3. The inner ring of the first bearing 4 is held between the step 2 b of the worm shaft 2 and a joint 9 press-fit into the end of the worm shaft 2. Thereby, the movement of the worm shaft 2 in the axial direction is restricted.

The distal end side of the worm shaft 2 is rotatably supported by a second bearing 11. The second bearing 11 is a ball bearing in which a ball 11c is interposed between an annular outer ring 11a and an inner ring 11b. The second bearing 11 is accommodated in a holder 30, and the holder 30 is disposed in an accommodation hole 3 d having a circular inner peripheral surface formed on the bottom side of the gear case 3.

The specific configuration of the holder 30 will be described below.

In the following, as shown in FIG. 2, the direction (left and right direction in FIG. 2) along the central axis of the worm shaft 2 (the central axis of the second bearing 11) is referred to as “first direction”, the center of the worm wheel 1 The direction along the axis (vertical direction in the drawing of FIG. 2) is “second direction”, and the direction perpendicular to both the central axis of the worm shaft 2 and the central axis of the worm wheel 1 (vertical direction in FIG. It is also called "direction". That is, the first direction, the second direction, and the third direction are directions along three orthogonal axes orthogonal to one another. Further, in the third direction, one side (upper side in FIG. 2) which is the worm wheel 1 side viewed from the second bearing 11 is “gear side”, and the other side (lower side in FIG. 2) opposite to the gear side. Is referred to as "anti-gear side".

As shown mainly in FIGS. 2 and 3, the holder 30 includes a first holder 40 having a holding portion 42 for holding the second bearing 11 and a guide portion for guiding the movement of the second bearing 11 toward the worm wheel 1. And a coil spring (hereinafter simply referred to as a "spring") 70 as a biasing member for biasing the second bearing 11 toward the worm wheel 1 via the first holder 40. And an arc-shaped clip 80 as a locking member for locking and integrating the first holder 40 and the second holder 60. The first holder 40 and the second holder 60 are made of resin.

As shown in FIG. 4 to FIG. 6, the first holder 40 has one of the plate-shaped first holder main body portion 41, the holding portion 42 provided on the first holder main body portion 41, and the outer peripheral surface of the second bearing 11. And a supporting portion 50 in which a spring receiving recess 55 for receiving the spring 70 is formed.

The first holder main body portion 41 is formed in a plate shape having a so-called two-face width shape in which a pair of parallel planes parallel to each other is formed. The first holder body 41 has a circular recess 41a provided at the center, and a central hole 41b formed at the bottom of the recess 41a and penetrating the first holder body 41 in the thickness direction (first direction). Have.

The recess 41a is provided to face the inner race 11b of the second bearing 11, as shown in FIG. 2, and has a larger inner diameter than the inner race 11b. The contact between the inner ring 11b of the second bearing 11 and the first holder main body 41 is avoided by the recess 41a. Thus, the rotation of the inner ring 11b of the second bearing 11 is not inhibited by the first holder 40, and the worm shaft 2 can be smoothly rotated.

The central hole 41 b is formed to have an inner diameter larger than the diameter of the end of the worm shaft 2 supported by the second bearing 11, and a part of the end of the worm shaft 2 is inserted. By inserting the end of the worm shaft 2 through the first holder main body 41 of the holder 30, the power steering device 100 can be miniaturized in the axial direction of the worm shaft 2.

The holding part 42 is comprised from the 1st holding part 42a and the 2nd holding part 42b which are provided facing each other on both sides of the central axis of the 2nd bearing 11, as shown to FIGS. The first holding portion 42 a and the second holding portion 42 b are provided to project in the same direction from the first holder main body portion 41 along the central axis of the second bearing 11 (along the first direction). The first holding portion 42a and the second holding portion 42b face each other in the third direction. The first holding portion 42a and the second holding portion 42b are formed in an arc shape whose inner side in the radial direction corresponds to the outer ring 11a of the second bearing 11, and the outer side is formed in an arc shape corresponding to the inner peripheral surface of the accommodation hole 3d. Ru. The first holding portion 42 a and the second holding portion 42 b hold a part of the outer peripheral surface of the outer ring 11 a of the second bearing 11 housed inside. The first holding portion 42a is relatively provided on the gear side, and the second holding portion 42b is relatively provided on the opposite gear side.

The opening 43 includes a first opening 43a and a second opening 43b which are divided by the first holding portion 42a and the second holding portion 42b in the circumferential direction of the second bearing 11. The first opening 43 a and the second opening 43 b are provided on both sides in the second direction with respect to the central axis of the second bearing 11. The first opening 43 a and the second opening 43 b communicate with the inner space of the first holding portion 42 a and the second holding portion 42 b that accommodate the second bearing 11. Thereby, as shown in FIG. 6, the first opening 43a and the second opening 43b are one of the outer peripheral surfaces of the outer ring 11a of the second bearing 11 held by the first holding portion 42a and the second holding portion 42b. Expose the unit to the outside.

The support part 50 is provided in the surface on the opposite side to the holding part 42 in the 1st holder main-body part 41, as shown in FIG. The support portion 50 is formed such that a cross section perpendicular to the first direction has a biplanar width shape having a pair of parallel surfaces (see FIG. 10). The support 50 has a spring receiving recess 55 for receiving the spring 70. The spring 70 is provided on the opposite side of the first holder main body 41 from the second bearing 11 held by the first holding portion 42 a and the second holding portion 42 b. Therefore, the spring 70 is provided so as to line up with the second bearing 11 in the axial direction (first direction).

As shown in FIGS. 7 and 8, the second holder 60 includes a disc-shaped second holder main body portion 61, a guide portion 62 provided on the second holder main body portion 61, and a holding portion 42 of the first holder 40. A holder opening 63 for permitting the passage of the second bearing 11 and a positioning projection 64 inserted in a positioning hole 3e (see FIG. 2) provided in the bottom wall 3c of the housing hole 3d of the gear case 3.

The second holder main body portion 61 has a receiving portion 65 for housing the support portion 50 of the first holder 40, and an arc-shaped groove portion 61a which extends in the circumferential direction and is formed on the outer peripheral surface.

The receiving portion 65 is a recess having an outer peripheral opening 65 a that opens to the outer peripheral surface of the second holder main body 61 on the gear side in the third direction. Further, the receiving portion 65 is opened at one end face of the second holder main body portion 61. The support portion 50 of the first holder 40 is inserted into the receiving portion 65 through the outer peripheral opening 65 a. The receiving portion 65 supports the spring 70 with the support portion 50 of the first holder 40 (see FIG. 10).

The groove portion 61a is a C-shaped arc-shaped groove whose both ends are separated in the circumferential direction by the partition portion 61b as shown in FIG. Further, as shown in FIG. 7, the groove 61 a communicates with the outer peripheral opening 65 a of the receiving portion 65. In other words, the groove 61a is separated into two by the outer peripheral opening 65a. The partition 61 b is provided on the opposite side to the third opening with respect to the outer peripheral opening 65 a across the central axis of the second bearing 11.

The guide part 62 consists of the 1st guide part 62a and the 2nd guide part 62b which mutually oppose on both sides of the 2nd bearing 11, as shown to FIGS. 7-9. The first guide portion 62a and the second guide portion 62b are formed to project in the same direction from the second holder main body portion 61 along the central axis of the second bearing 11 (see FIGS. 7 and 8). In addition, in FIG. 9, the 2nd bearing 11 is simplified and represented.

The first guide portion 62a and the second guide portion 62b are formed with a pair of guide surfaces 62c and 62d which are planes extending in the third direction and parallel to each other. The distance between the pair of guide surfaces 62 c and 62 d is formed slightly larger than the outer diameter of the outer ring 11 a of the second bearing 11. In the second bearing 11, the outer peripheral surface of the outer ring 11a contacts the pair of guide surfaces 62c and 62d, and the movement along the third direction toward the worm hole 1 is guided by the pair of guide surfaces 62c and 62d.

The length (the length in the first direction) at which the first guide portion 62a and the second guide portion 62b protrude from the second holder main portion 61 is larger than the thickness (the axial length) of the second bearing 11 Be done. Further, as shown in FIG. 7,

claw portions

62e and 62f extending toward the central axis of the second bearing 11 are formed at the tips of the first guide portion 62a and the second guide portion 62b. The

claws

62e and 62f prevent the second bearing 11 held by the first holder 40 from falling off the first holder 40 in the axial direction (first direction) (see FIG. 3).

The holder opening 63 is, as shown in FIG. 7, from the first holder opening 63 a and the second holder opening 63 b which are partitioned by the first guide 62 a and the second guide 62 b in the circumferential direction of the second bearing 11. Become. That is, in the second holder 60, the first holder opening 63a and the second holder opening 63b are formed so as to cut out the circumferential direction between the first guide 62a and the second guide 62b. In the first holder opening 63a and the second holder opening 63b, the first holder opening 63a is relatively provided on the gear side in the third direction, and the second holder opening 63b is relatively opposite in the third direction. It is provided on the gear side. The first holder opening 63 a and the second holder opening 63 b pass through the first holding portion 42 a and the second holding portion 42 b of the first holder 40 and the second bearing 11 held by the first holder 40, respectively. Allow

As shown in FIGS. 3 and 9, in a state where the first holder 40 and the second holder 60 are assembled, the first holding portion 42 a and the second holding portion 42 b of the first holder 40 are the second of the second holder 60. The first guide portion 62a and the second guide portion 62b are adjacent to each other in the circumferential direction of the second bearing 11 through the first holder opening 63a and the second holder opening 63b (see FIGS. 7 and 8). In other words, the first guide portion 62a and the second guide portion 62b of the second holder 60 are provided along the periphery of the second bearing 11 through the first opening 43a and the second opening 43b (see FIG. 4) of the first holder 40. It adjoins the 1st holding part 42a and the 2nd holding part 42b in a direction. Furthermore, the first holding portion 42a, the second holding portion 42b, the first guide portion 62a, and the second guide portion 62b face the inner peripheral surface of the housing hole 3d of the gear case 3, respectively. Thus, the first holder 40 and the second holder 60 are provided so as not to overlap with each other between the second bearing 11 and the accommodation hole 3 d in the radial direction. Therefore, the holder 30 can be made compact in the radial direction of the second bearing 11.

As shown in FIG. 8, the positioning convex portion 64 is provided so as to be connected to the second holder main body portion 61 on the side opposite to the guide portion 62 in the axial direction. The positioning convex portion 64 is provided at a position radially away from the central axis of the second bearing 11. The positioning convex portion 64 fits with a clearance in a positioning hole 3e (see FIG. 2) formed in the bottom wall 3c of the housing hole 3d. Thereby, the holder 30 is positioned with respect to the gear case 3, and the rotation of the holder 30 in the accommodation hole 3d is restricted.

The spring 70 is held in a compressed state between the support portion 50 of the first holder 40 and the receiving portion 65 of the second holder 60, as shown in FIG. The spring 70 exerts an urging force such that the first holder 40 and the second holder 60 are separated from each other in the third direction. Thereby, the spring 70 biases the second bearing 11 in the direction in which the gap between the tooth 2 a of the worm shaft 2 and the tooth of the worm wheel 1 is reduced. That is, the spring 70 biases the worm shaft 2 toward the worm wheel 1 via the second bearing 11. The support structure of the spring 70 will be described in detail later.

The clip 80 is a metal C-shaped member having a circular cross section, as shown in FIGS. 10 and 11. The clip 80 is attached to the groove 61 a across the outer peripheral opening 65 a of the receiving portion 65. As a result, the second bearing 11 and the first holder 40 are restricted from falling off the second holder 60 through the outer peripheral opening 65 a and the first holder opening 63 a of the receiving portion 65 by the biasing force of the spring 70. Thus, the clip 80 locks the first holder 40 and the second holder 60.

In the present specification, the locking of the first holder 40 and the second holder 60 means the first urging force of the spring 70 when the holder 30 is not attached to the housing hole 3 d of the gear case 3. It indicates a state in which the holder 40 is restricted from coming out (separation) from the inside of the second holder 60.

The width in the third direction of the support portion 50 of the first holder 40 is smaller than the width in the third direction of the receiving portion 65 of the second holder 60, as shown in FIG. Therefore, in a state where the first holder 40 and the second holder 60 are locked by the clip 80, the support portion 50 is movable in the third direction between the clip 80 and the receiving portion 65. That is, in the state where the holder 30 is not assembled in the housing hole 3 d, the first holder 40 is in a state where the support portion 50 contacts the clip 80 and the support portion 50 on the inner circumferential surface of the receiving portion 65 of the second holder 60. It is movable in the third direction between the contacting state. The locking structure between the first holder 40 and the second holder 60 by the clip 80 will be described in detail later.

In a state where the first holder 40 and the second holder 60 are assembled, as shown in FIG. 9, the outer peripheral surface of the second bearing 11 exposed from the first opening 43a and the second opening 43b is a first guide portion It contacts the guide surfaces 62c and 62d of the second guide portion 62b. The spring 70 is provided between the first holder 40 and the second holder 60 and biases the first holder 40 and the second holder 60 so as to be separated from each other. Therefore, the movement of the second bearing 11 is directly guided by the pair of guide surfaces 62c and 62d parallel to each other. As described above, in the present embodiment, the second metal bearing 11 and the second resin holder 60 contact with each other with a difference in hardness.

As described above, in the holder 30, since the second bearing 11 directly contacts the guide portion 62, the dimensional accuracy of the first holder 40 is prevented from affecting the meshing accuracy of the worm wheel 1 and the worm shaft 2. Can.

Next, a support structure for supporting the spring 70 by the first holder 40 and the second holder 60 will be described in detail.

As shown in FIGS. 5 and 10, the support portion 50 has a first support portion 51 capable of supporting the spring 70 so as to exert an urging force in the first urging direction, and an urging force in the second urging direction. And a second support 52 capable of supporting the spring 70 to exert the force. The first biasing direction is a direction inclined with respect to a third direction in which the second bearing 11 is guided by the guide portion 62. The second biasing direction is inclined with respect to the third direction and is a direction different from the first biasing direction.

The spring receiving recess 55 opens in the opposite direction to the gear in the third direction and opens at the end face 50 a of the support 50 perpendicular to the first direction. The central hole 41 b of the first holder main body 41 opens in the spring accommodation recess 55.

The spring accommodating recess 55 is capable of accommodating the spring 70 capable of accommodating the spring 70 exerting the urging force in the first urging direction, and the spring accommodating recess 55 is capable of accommodating the spring 70 so as to exert the urging force in the second urging direction. And 2 accommodation recess 57. The first accommodation recess 56 is partitioned by the first support portion 51. The second accommodation recess 57 is partitioned by the second support portion 52.

As shown in FIG. 10, the first support portion 51 (first accommodation recess 56) and the second support portion 52 (second accommodation recess 57) are provided mirror-symmetrically to the reference plane M parallel to the third direction. Be The first accommodation recess 56 and the second accommodation recess 57 are provided to intersect and communicate with each other. The first accommodation recess 56 and the second accommodation recess 57 cross each other at a position facing the central hole 41 b.

The first support portion 51 has a first seating surface 51a perpendicular to the first biasing direction, planar first side wall surfaces 51b and 51c extending in the first biasing direction, and a cross section perpendicular to the first biasing direction. And a first peripheral wall surface 51 d formed in an arc shape. One of the first side wall surfaces 51 b is formed of the first seating surface 51 a and is opposed to the spring 70 accommodated in the first accommodation recess 56. The other first side wall surface 51 c is separated from the first seating surface 51 a by a second accommodation recess 57 partitioned by the second support portion 52. The first peripheral wall surface 51 d is connected to the first seating surface 51 a and the first side wall surfaces 51 b and 51 c, respectively. The movement of the spring 70 accommodated in the first accommodation recess 56 is restricted by the first support portion 51 so as to be inclined with respect to the first biasing direction.

The second support portion 52 has a second seating surface 52a perpendicular to the second biasing direction, planar second side wall surfaces 52b and 52c extending in the second biasing direction, and a cross section perpendicular to the second biasing direction. Is formed by a second peripheral wall surface 52 d formed in an arc shape. One second side wall surface 52 b is formed of the second seating surface 52 a and is opposed to the spring 70 housed in the second accommodation recess 57. The other second side wall surface 52 c is separated from the second seating surface 52 a by a first accommodation recess 56 partitioned by the first support portion 51. The second peripheral wall surface 52 d is connected to the second seating surface 52 a and the second side wall surfaces 52 b and 52 c, respectively. The second support portion 52 restricts the movement of the spring 70 accommodated in the second accommodation recess 57 so as to be inclined with respect to the second biasing direction.

As shown in FIG. 10, the receiving portion 65 of the second holder 60 has a first receiving surface 67 perpendicular to the first biasing direction and a second receiving surface 68 perpendicular to the second biasing direction. The spring 70 supported by the first support 51 rests on the first receiving surface 67. A spring 70 supported by the second support 52 rests on the second receiving surface 68. The shape of the receiving portion 65 is not limited to this, and it is only necessary that the spring 70 supported by the first support portion 51 and the spring 70 supported by the second support portion 52 can be seated. For example, the first receiving surface 67 and the second receiving surface 68 may be formed in a continuous circular arc surface.

The opening of the spring receiving recess 55 with respect to the end surface 50 a of the support portion 50 is closed by the side surface 65 b (see FIG. 7) of the receiving portion 65. Thereby, the spring 70 supported by the first support portion 51 or the second support portion 52 is the first

side wall surface

51b, 51c or the second

side wall surface

52b, 52c, the first peripheral wall surface from four sides around the central axis thereof It is surrounded by 51 d or the second peripheral wall 52 d and the side surface 65 b of the receiving portion 65. Therefore, the spring 70 is stably supported.

Further, the support portion 50 is provided with a projection 58 as a misassembly preventing portion for preventing misassembly in which the spring 70 is assembled in a wrong biasing direction. In the present embodiment, since the spring 70 is supported by the first support portion 51, as shown in FIG. 10, the projection 58 is provided so as to project in the first direction from the second peripheral wall 52d of the second support portion 52. . Thereby, when the spring 70 to be originally supported by the first support portion 51 is supported by the second support portion 52, the spring 70 is lifted from the second peripheral wall surface 52d by the projection 58, and the end face of the support portion 50 A portion of the spring 70 projects from 50a. In this state, the support portion 50 can not be inserted into the receiving portion 65 together with the spring 70, and the first holder 40 and the second holder 60 can not be assembled, so that erroneous assembly can be detected. As described above, when the spring 70 is supported by the second support portion 52 which originally does not support the spring 70 by the projection 58, the assembly of the first holder 40 and the second holder 60 is inhibited, preventing erroneous assembly. can do.

When the spring 70 is supported by the second support portion 52, the protrusion 58 is provided on the first peripheral wall surface 51d of the first support portion 51. In addition, the projections 58 are not limited to the first peripheral wall surface 51d or the second peripheral wall surface 52d, and are provided on the first and second seating surfaces 51a and 52a and the first and second side wall surfaces 51b, 51c, 52b and 52c. It is also good. In order to prevent the assembling error more reliably by increasing the amount of floating of the spring 70, the projection 58 is positioned as far as possible from the first and second seating surfaces 51a and 52a, for example, the center It is desirable to be provided at a position farther from the first and second seating surfaces 51a and 52a than the hole 41b. Further, the projection 58 may be provided not only in the first holder 40 but also in the receiving portion 65 of the second holder 60.

Here, the reaction force from the worm wheel 1 to the worm shaft 2 acts in different directions depending on the rotation direction of the worm shaft 2. Therefore, in order to apply an appropriate biasing force to the meshing portion of worm shaft 2 and worm wheel 1 while opposing the reaction force from worm wheel 1, spring 70 is directed between the axis of worm wheel 1 and worm shaft 2 ( It is desirable to arrange to bias the worm shaft 2 with respect to the third direction).

On the other hand, the power steering apparatus 100 differs in the structure by the case where it mounts in a right-hand drive vehicle, and the case where it mounts in a left-hand drive vehicle. Specifically, since the inclination angle of the output shaft 22 with respect to the rack shaft 8 is inverted with respect to the vehicle center, the twisting directions of the worm wheel 1 become opposite to each other. Therefore, the directions of the appropriate biasing force applied to the meshing portion by the spring 70 are different between the right-hand drive car and the left-hand drive car.

On the other hand, in the present embodiment, the spring 70 is selectively supported by the first support portion 51 and the second support portion 52. The first support portion 51 and the second support portion 52 can support the spring 70 so as to exert the biasing force in two directions of the first biasing direction and the second biasing direction. For this reason, the first biasing direction is a direction in which the right-hand drive wheel exerts an appropriate biasing force on the meshing portion, and the second biasing direction is a direction in which the left-hand drive car exerts an appropriate biasing force on the meshing portion Thus, even when the power steering apparatus 100 is mounted on either a right-hand drive car or a left-hand drive car, the common holder 30 can be used.

Since the common holder 30 can be used, a mold or the like for manufacturing the holder 30 can be made common, and the manufacturing cost can be reduced. As described above, even in the case where the projection 58 is provided as the erroneous assembly preventing portion, the mold itself can be made common since the mold for forming the projection 58 may be inserted into the mold. Therefore, even in the case of forming the projection 58 as the erroneous assembly preventing portion, the manufacturing cost can be reduced.

The first accommodation recess 56 and the second accommodation recess 57 intersect at a position facing the central hole 41 b. For this reason, the spring 70 is supported so as to face the central hole 41 b regardless of whether the spring 70 is supported by the first support portion 51 or supported by the second support portion 52. Therefore, even after the first holder 40, the second holder 60, and the second bearing 11 are assembled and integrated, the inclination (biasing of the spring 70 through the hole of the inner ring 11b of the second bearing 11 and the central hole 41b ) Can see the direction. Thus, even after the holder 30 is assembled, it can be easily confirmed which of the first support portion 51 and the second support portion 52 the spring 70 is supported by. As described above, by confirming the biasing direction of the spring 70, it is possible to easily confirm whether the steering wheel position of the vehicle and the biasing direction of the spring 70 are an appropriate combination, and incorrect assembly can be prevented.

Next, a locking structure for locking the first holder 40 and the second holder 60 will be described in detail.

As shown in FIG. 11, the clip 80 is formed by bending a wire having a uniform circular cross section into a C-shape. The wire diameter (thickness) of the clip 80 is uniform in the circumferential direction.

The depth (the length along the radial direction of the central axis of the second holder 60) of the groove 61a of the second holder 60 is slightly larger than the wire diameter of the clip 80 and uniform in the circumferential direction. The radius of curvature R1 (see FIG. 10) of the bottom (portion defining the depth) of the groove 61a is larger than the radius of curvature R2 (see FIG. 11) of the inner periphery of the clip 80 in the natural state. As a result, when the clip 80 is mounted in the groove 61a while expanding the clip 80, as shown in FIG. 10, both ends of the clip 80 contact the bottom of the groove 61a and are elastically deformed with the both ends as fulcrums. In the clip 80, the positions (portion A in FIG. 10) on both sides in the circumferential direction of the outer peripheral opening 65a of the receiving portion 65 expand most greatly, and a part protrudes radially outward from the outer peripheral surface of the second holder main body 61 . Therefore, the outer diameter of the holder 30 as a whole, specifically, the maximum width between the second holder body 61 and the outer periphery of the clip 80 becomes larger than the inner diameter of the accommodation hole 3d.

When the holder 30 is assembled to the housing hole 3 d of the gear case 3, the portion of the clip 80 that bulges radially outward from the outer peripheral surface of the second holder body 61 is pushed radially inward. Therefore, as shown in FIG. 12, the clip 80 pushed inward in the radial direction contacts and presses the second holder main body 61 (portion B in FIG. 12). As a result, the second holder 60 receives an elastic force from the portion of the clip 80 that bulges the most, and is biased in the third direction away from the worm wheel 1 in the opposite direction to the gear. In this manner, the holder 30 is elastically supported relative to the accommodation hole 3d by the elastic force of the clip 80.

Further, the second holder main body portion 61 of the second holder 60 receives the elastic force (biasing force) of the clip 80, and is pressed against the inner peripheral surface of the accommodation hole 3d. More specifically, in the second holder main body 61, a part of the outer periphery extending in the axial direction from the partition wall 61b and the partition wall 61b is pressed against the inner peripheral surface of the accommodation hole 3d.

Here, when the second holder 60 is not in contact with the inner peripheral surface on the opposite gear side of the accommodation hole 3d, when a reaction force is applied from the worm wheel 1 to the worm shaft 2, the first holder 40 exerts an urging force of the spring 70. , And the second holder 60 also moves to the opposite gear side against the elastic force of the clip 80. Thus, since both the 1st holder 40 and the 2nd holder 60 which support spring 70 will move, the energizing force which spring 70 exerts varies, and it becomes unstable.

On the other hand, in the present embodiment, the second holder 60 contacts the inner peripheral surface of the accommodation hole 3d in a stationary state where no reaction force is exerted on the worm shaft 2 from the worm wheel 1. For this reason, even if a reaction force is applied from the worm wheel 1, further movement of the second holder 60 in the direction away from the worm wheel 1 is restricted. By restricting the movement of the second holder 60 that supports one end of the spring 70, one end of the spring 70 is grounded. Therefore, a stable biasing force can be exerted against the reaction force of the worm wheel 1. Therefore, backlash can be reduced more reliably.

In the clip 80 and the groove 61a of the second holder 60, an elastic force (biasing force) for pressing the second holder 60 toward the opposite gear side to the inner peripheral surface of the accommodation hole 3d is the second hole 60. It is configured to be larger than the frictional force generated when moving to the inner circumferential surface of the. Specifically, the clip 80 and the groove portion 61 a have a frictional force generated between the second holder 60 and the first holder 40, and the first and

second guide portions

62 a and 62 b of the second holder 60 and the second bearing 11. The biasing force of the clip 80 for biasing the second holder 60 is greater than the resultant force of the friction force generated between the two. Furthermore, the clip 80 exerts an urging force on the second holder 60 such that the clip 80 and the groove 61a overcome the frictional force generated in the second holder 60 with respect to the first holder 40 and the second bearing 11. Configured to As a result, the second holder 60 can be more reliably pressed against the inner peripheral surface of the accommodation hole 3d by the clip 80 toward the opposite gear side.

Further, as described above, the first holder 40 and the second holder 60 are configured not to overlap in the radial direction of the second bearing 11, and the spring 70 is between the first holder 40 and the second holder 60. And is axially separated from the second bearing 11. Thereby, holder 30 can be made into a compact composition. On the other hand, with such a configuration, the first holder 40 receives the biasing force of the spring 70 so as to come out of the second holder 60. On the other hand, in the present embodiment, the first holder 40 and the second holder 60 are locked by the clip 80 so that the first holder 40 does not separate from each other by receiving the biasing force of the spring 70. The first holder 40, the second holder 60, and the second bearing 11 are integrated by the clip 80 by the clip 80, so that they can be integrated into the housing hole 3d of the gear case 3 as one unit, and the assemblability is improved. . Therefore, while the holder 30 becomes a compact structure, the assemblability to the accommodation hole 3d is also improved.

Furthermore, since the holder 30 is elastically supported by the clip 80 which integrates the holder 30, the holding force of the holder 30 with respect to the accommodation hole 3d can be secured without increasing the number of parts. Further, since the second holder 60 is pressed against the inner peripheral surface of the accommodation hole 3d by the elastic force of the clip 80, the biasing force of the spring 70 can be stabilized.

As described above, in the present embodiment, the first holder 40 and the second holder 60 are configured so as not to overlap on the radially outer side of the second bearing 11, and the clip 80 allows the first holder 40 and the second holder 60 And the holder 30 is elastically supported. Thereby, without increasing the number of parts, the effects of compacting the configuration, securing the assemblability of the holder 30 into the housing hole 3 d, securing the holding power of the holder 30, and stabilizing the biasing force of the spring 70 are integrated. Can play.

Further, the groove 61 a is formed in a C shape corresponding to the shape of the clip 80 with both ends separated by the partition wall 61 b so as to correspond to the C shape of the clip 80. Therefore, movement of the clip 80 accommodated in the groove 61a in the circumferential direction is restricted by the both ends being in contact with the partition wall 61b at the end of the groove 61a. That is, since the relative rotation between the clip 80 and the second holder 60 is restricted by the partition wall 61b, the clip 80 is mounted so as to always face the outer peripheral opening 65a of the receiving portion 65. Thereby, the falling off of the first holder 40 and the second bearing 11 through the outer peripheral opening 65 a of the receiving portion 65 is more reliably prevented.

In addition, the partition part 61b is not provided in the 2nd holder 60 not only in this, but the groove part 61a may be an annular groove. In this case, it is desirable that the circumferential gap between both ends of the clip 80 be smaller than the width of the outer peripheral opening 65 a (the outer diameter of the second bearing 11). According to this, even when the gap of the clip 80 and the outer peripheral opening 65a overlap, the second bearing 11 and the first holder 40 are prevented from dropping through the gap. When the gap of the clip 80 and the outer peripheral opening 65a overlap and the second bearing 11 and the first holder 40 do not fall off, the groove 61a is formed annularly, and the gap of the clip 80 is the outer peripheral opening 65a. (The outer diameter of the second bearing 11) may be larger.

Next, the assembly of the holder 30 and the power steering apparatus 100 will be described.

In assembling the holder 30 and the second bearing 11, as shown in FIG. 13, first, the second bearing 11 is accommodated inside the first holding portion 42a and the second holding portion 42b of the first holder 40, and the first holding is performed. The second bearing 11 is held by the portion 42a and the second holding portion 42b. In this state, a part of the outer peripheral surface of the second bearing 11 is exposed by the first opening 43a and the second opening 43b. Further, the spring 70 is accommodated in the spring accommodating recess 55 in the support portion 50 of the first holder 40, and the spring 70 is supported by the first support portion 51.

Next, the outer circumferential surface of the second bearing 11 exposed from the first opening 43a and the second opening 43b contacts the guide surfaces 62c and 62d (see FIG. 9 etc.) of the first guide 62a and the second guide 62b. As a result, the first holder 40 and the second bearing 11 are assembled to the second holder 60. More specifically, as shown in FIG. 14, the support portion 50 of the first holder 40 and the spring 70 are inserted into the receiving portion 65 of the second holder 60 from the radial direction of the second bearing 11 through the outer peripheral opening 65 a. As described above, since the biasing direction of the spring 70 and the insertion direction of the first holder 40 and the second bearing 11 into the second holder 60 substantially coincide with each other, the assembly can be easily performed.

Next, the clip 80 is wound around the outer periphery of the second holder 60 while the diameter of the clip 80 is expanded, and the clip 80 is attached to the groove 61a. Thereby, the first holder 40 and the second holder 60 are prevented from being separated by the clip 80 and locked via the clip 80. Further, as described above, the curvature radius R2 of the inner periphery of the clip 80 is formed smaller than the curvature radius R1 of the bottom of the groove 61a. Therefore, when the holder 30 is not attached to the gear case 3, a part of the clip 80 slightly protrudes from the outer peripheral surface of the second holder 60 (see FIG. 10).

Next, the holder 30 is assembled to the housing hole 3 d of the gear case 3. At this time, a portion of the clip 80 that protrudes from the groove 61 a is pushed radially inward, and the second holder 60 is biased by the clip 80 in the third direction so as to be separated from the worm wheel 1. Therefore, the holder 30 is elastically supported with respect to the accommodation hole 3 d by the biasing force of the clip 80.

After the holder 30 is assembled to the gear case 3 in this manner, the front end portion of the worm shaft 2 is inserted into the hollow portion in the center of the second bearing 11, whereby the assembly of the power steering apparatus 100 is completed.

The worm shaft 2 receives an urging force from the spring 70 toward the worm wheel 1 via the first holder 40 and the second bearing 11 in a state where the worm shaft 2 is inserted into the second bearing 11. Thereby, the backlash between the worm shaft 2 and the worm wheel 1 is reduced, and the meshing accuracy between the worm shaft 2 and the worm wheel 1 is secured.

In the state where the worm shaft 2 is inserted into the second bearing 11, the first holder 40 does not contact the inner peripheral surface of the accommodation hole 3d and is separated (see FIG. 2). As the rotation of the worm shaft 2 is repeated and the meshing portion between the worm shaft 2 and the worm wheel 1 wears, the first holder 40 receives the biasing force of the spring 70 and approaches the inner circumferential surface of the accommodation hole 3d. Thereby, even if the meshing portion between the worm shaft 2 and the worm wheel 1 wears, the backlash can be reduced. The first holder 40 is movable toward the worm wheel 1 until it contacts the inner circumferential surface of the housing hole 3d. In other words, the movement of the first holder 40 in the third direction toward the gear side is restricted by the inner peripheral surface of the accommodation hole 3d.

Next, a modification of the present embodiment will be described. The following modifications are also within the scope of the present invention, and the following modifications and each configuration of the above embodiment may be combined, or the following modifications may be combined with other embodiments described later and their modifications, It is also possible to combine the following modifications. Moreover, it is possible to combine with another modification and another embodiment similarly about the modification described in description of the said embodiment.

First, with reference to FIGS. 15-17, the modification of the latching structure of the 1st holder 40 and the 2nd holder 60 by the clip 80 is demonstrated. In FIGS. 15 and 16, only the clip 80 and the second holder 60 are shown, and the other components are not shown.

In the above embodiment, the clip 80 has a uniform wire diameter, and the groove 61a has a uniform depth. The radius of curvature R2 of the inner periphery of the clip 80 is smaller than the radius of curvature R1 of the bottom of the groove 61a. In addition, the holder 30 is elastically supported by the clip 80 with respect to the accommodation hole 3 d. On the other hand, the holder 30 may not necessarily be elastically supported with respect to the accommodation hole 3d.

When the holder 30 is elastically supported, the clip 80 may not necessarily press the second holder 60 against the inner peripheral surface of the accommodation hole 3 d. Further, even in the case where the second holder 60 is pressed against the inner peripheral surface of the housing hole 3d, the clip 80 and the groove 61a can have any configuration without being limited to the above embodiment. In a state before the holder 30 is assembled into the accommodation hole 3d, a part of the clip 80 bulges radially outward, and when the holder 30 is assembled into the accommodation hole 3d, the clip 80 is contracted to accommodate the second holder 60 in the accommodation hole 3d. Any configuration may be used as long as it is biased toward the inner circumferential surface of

For example, the wire diameter of the clip 80 and the depth (diameter) of the bottom of the groove 61a may be configured to change in the circumferential direction. Describing the case where the depth of the bottom of the groove 61a changes, as an example, as shown in FIG. 15, the bottom of the groove 61a is formed so as to become shallower as it is separated from the partition 61b in the circumferential direction. In other words, the center of curvature of the bottom portion of the groove 61 a is formed to be eccentric to the gear side in the third direction with respect to the center of curvature of the outer peripheral surface of the second holder body 61 in the second holder 60. According to this, when the clip 80 is attached to the groove 61a, a part of the clip 80 attached to the shallow part of the groove 61a bulges radially outward from the groove 61a.

When the clip 80 is attached to the groove 61a and the holder 30 is assembled to the receiving hole 3d, the outer periphery of the clip 80 contacts the inner circumferential surface of the receiving hole 3d. For this reason, when the holder 30 is assembled in the housing hole 3d, the second holder main body portion 61 is pressed by the inner periphery of the clip 80 from the gear side with a shallow depth toward the opposite gear side. Thus, the holder 30 can be elastically supported by the clip 80 and the second holder 60 can be pressed against the inner peripheral surface of the accommodation hole 3 d as in the above embodiment. In this case, the radius of curvature of the clip 80 and the radius of curvature of the bottom of the groove 61a may be the same. Also in the case where the wire diameter of the clip 80 is changed in the circumferential direction, the wire diameter of the portion to be the gear side may be similarly increased. In this case, the center of curvature of the outer periphery of the clip 80 is eccentric to the gear side in the third direction with respect to the outer peripheral surface of the second holder main body 61 in a state where the clip 80 is attached to the groove 61a. Note that both the wire diameter of the clip 80 and the depth of the groove 61a may be changed in the circumferential direction.

Also, for example, as shown in FIG. 16, the inner periphery of the clip 80 or the bottom of the groove 61 a may be provided with a raised portion 80 a that bulges the clip 80 outward in the radial direction. When provided on the clip 80, the raised portion 80a protrudes radially inward from the inner periphery of the clip 80 (see FIG. 16). Moreover, although illustration is abbreviate | omitted, when provided in the groove part 61a, the protruding part 80a is provided protruding in the radial direction outer side from a bottom part, or protruding inward from the side part of the groove part 61a. By providing the protruding portion 80a in the clip 80 or the groove 61a, when the clip 80 is attached to the groove 61a, the protruding portion 80a causes the clip 80 to expand radially outward. Thus, the holder 30 can be elastically supported by the clip 80 and the second holder 60 can be pressed against the inner peripheral surface of the accommodation hole 3 d as in the above embodiment. It is desirable that the protruding portions 80a be provided on both sides in the circumferential direction of the outer peripheral opening 65a in the receiving portion 65 of the second holder 60, as in the above embodiment. The raised portion 80a may be provided on both the clip 80 and the groove 61a.

Also, the clip 80 and / or the groove 61a may be formed in an oval or other shape instead of the shape of a regular arc. As another shape, for example, as shown in FIG. 17, the clip 80 has a linear shape connecting a pair of arc portions 80b formed with a curvature radius R2 smaller than the curvature radius R1 of the groove portion 61a and a pair of arc portions 80b. And the connection portion 80c of In this case, when the clip 80 is attached to the groove 61a, two portions of the boundary portion (connection portion) between the pair of arc portions 80b and the connection portion 80c expand radially outward. Therefore, the holder 30 is elastically supported on the gear case 3 by the two boundary portions which bulge in the clip 80. Even in this case, the same effect as the above embodiment can be obtained.

As mentioned above, when elastically supporting the holder 30 with respect to 3 d of accommodation holes, not only the structure in the said embodiment but another structure may be sufficient.

When the second holder 60 is pressed against the inner peripheral surface of the housing hole 3d by the elastic force of the clip 80, as in the above embodiment, two portions of the clip 80 on both sides in the circumferential direction of the second opening 43b are greatly expanded. Preferably, elastic force acts on the holder 30 from two directions. According to this, it is possible to stably press the circular second holder 60 toward the opposite side to the worm wheel 1 against the inner peripheral surface of the accommodation hole 3d. In addition, not only this but the clip 80 and the groove part 61a may be comprised so that the 2nd holder 60 may receive an elastic force from one place or three or more places.

Next, other modifications of the present embodiment will be described.

In the above embodiment, the first holding portion 42a and the second holding portion 42b of the first holder 40 are provided in the housing hole 3d of the gear case 3 through the first holder opening 63a and the second holder opening 63b of the second holder 60. Face the inner surface. Further, the second bearing 11 is exposed through the first opening 43a and the second opening 43b of the first holder 40, and contacts the first guide 62a and the second guide 62b of the second holder 60. On the other hand, these configurations are not essential.

Further, in the above embodiment, the first support portion 51 has the first seating surface 51a, the first side wall surfaces 51b and 51c, and the first peripheral wall surface 51d. The second support portion 52 has a second seating surface 52a, second side wall surfaces 52b and 52c, and a second peripheral wall surface 52d. That is, the first support portion 51 and the second support portion 52 are formed by wall surfaces that define the spring receiving recess 55 for receiving the spring 70. On the other hand, as long as the first support portion 51 and the second support portion 52 can support the spring 70 so as to exert the biasing force in the first biasing direction and the second biasing direction, the configuration is not limited to the above. It can be of any configuration. For example, the first support portion 51 and the second support portion 52 may be protrusions inserted into the inside of the spring 70 to support the spring 70 on the inner periphery. In this case, the protrusion may be provided on any of the support portion 50 of the first holder 40 and the receiving portion 65 of the second holder 60.

According to the first embodiment described above, the following effects can be obtained.

In the power steering apparatus 100, the second bearing 11 is brought into direct contact with the guide surfaces 62c and 62d of the first guide portion 62a and the second guide portion 62b of the second holder 60 so that the movement is guided. Thus, the second bearing 11 is not guided to move through the first holder 40, but is directly guided by the first guide portion 62a and the second guide portion 62b. It is possible to suppress that the dimensional accuracy of the component affects the meshing accuracy. Therefore, the meshing accuracy between the worm wheel 1 and the worm shaft 2 can be improved.

Also, the spring 70 is held by the first holder 40 and the second holder 60. The spring 70 does not bias the second bearing 11 from the radially outer side in line with the second bearing 11 in the radial direction, and the second bearing 11 is axially aligned with the second bearing 11 via the first holder 40. The bearing 11 is biased. For this reason, the enlargement of the second bearing 11 in the radial direction can be prevented.

Further, the holder 30 supports the first support portion 51 supporting the spring 70 so as to exert the urging force in the first urging direction, and the holder 30 supports the spring 70 so as to exert the urging force in the second urging direction. And 2 support portions 52. Therefore, even when the power steering apparatus 100 is mounted on either the left-hand drive vehicle or the right-hand drive vehicle, the common holder 30 causes the spring 70 to exert a biasing force in an appropriate direction according to the steering wheel position. Can. Therefore, since it is not necessary to manufacture the holder 30 for every vehicle type and the mold which manufactures the holder 30 is made common, manufacturing cost can be reduced.

In addition, since the holder 30 includes the projection 58, if the spring 70 is supported by one of the first support portion 51 and the second support portion 52 that does not support the spring 70, it is easily detected that the assembly is incorrect. be able to.

Further, the first holder 40 has a central hole 41 b for avoiding the interference of the worm shaft 2, and the biasing direction of the spring 70 can be visually observed through the central hole 41 b. Therefore, even in the state where the first holder 40 and the second holder 60 are assembled, it is possible to easily detect an incorrect assembly in which the biasing direction of the spring 70 is different by visual observation through the central hole 41b.

Further, in the holder 30, the second holder 60 has the holder opening 63 for allowing the holding portion 42 of the first holder 40 and the second bearing 11 to pass, and the holding portion 42 of the first holder 40 has the holder opening It faces the inner peripheral surface of the accommodation hole 3 d through the portion 63. The movement of the first holder 40 is restricted by the first holding portion 42a and the second holding portion 42b coming into contact with the inner peripheral surface of the housing hole 3d through the first opening 43a and the second opening 43b. Therefore, in the holder 30, the first holding portion 42a and the second holding portion 42b of the first holder 40 pass the first guide portion 62a and the second holding portion 42 through the first opening 43a and the second opening 43b of the second holder 60, respectively. The guide portion 62b is arranged in the circumferential direction. As described above, since the first holder 40 and the second holder 60 do not overlap in the radial direction of the second bearing 11, the configuration of the holder 30 can be made compact. Furthermore, the meshing accuracy between the worm wheel 1 and the worm shaft 2 in the third direction is further improved because the dimensional accuracy of the second holder 60 is not affected.

Further, in the holder 30, the first holder 40 and the second holder 60 are locked by the clip 80, and the first holder 40 and the second bearing 11 are restricted from coming off the second holder 60 through the holder opening 63. . The clip 80 elastically supports the holder 30 with respect to the accommodation hole 3d. Thereby, while holding the 1st holder 40 and the 2nd holder 60 by a single clip 80, the retention power of holder 30 to accommodation hole 3d can be secured, and a part mark can be reduced.

Further, in the holder 30, the second holder 60 is urged in a direction away from the worm wheel 1 by the elastic force of the clip 80 and pressed against the inner peripheral surface of the accommodation hole 3 d. As a result, the biasing force for biasing the worm shaft 2 to the worm wheel 1 by the spring 70 is not affected by the elastic force of the clip 80, so that the worm shaft 2 can be stably biased.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIGS. 18 and 19. Hereinafter, differences from the first embodiment will be mainly described, and the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

In the second embodiment, the structure for locking the first holder 40 and the second holder 60 is different from that of the first embodiment. In the first embodiment, the locking member for locking the first holder 40 and the second holder 60 is the C-shaped clip 80, whereas the holder 130 of the second embodiment is not Instead, an elastic ring 180 is provided as a locking member. The details will be described below. The configuration other than the locking structure between the first holder 40 and the second holder 60 is the same as that of the first embodiment, and thus the description and the illustration will be appropriately omitted.

As shown in FIG. 18, an annular annular groove 161 a is formed on the outer peripheral surface of the second holder main body portion 161 of the second holder 160. The annular groove 161a has an arc cross section. The annular groove 161a is the deepest portion 161b which is deepest on the opposite gear side in the third direction with respect to the center of the second holder main portion 61, and the shallowest portion 161c which is shallowest on the gear side. The depth of the annular groove 161a gradually decreases from the deepest portion 161b to the shallowest portion 161c. The annular groove 161 a communicates with the outer peripheral opening 65 a of the receiving portion 65 and is separated by the outer peripheral opening 65 a. Therefore, the center of curvature O1 of the bottom portion of the annular groove 161a is eccentric to the gear side in the third direction with respect to the center of curvature O2 of the outer peripheral surface of the second holder body 61 in the second holder 60.

The elastic ring 180 is a resin O-ring having a circular cross section. The wire diameter of the elastic ring 180 is formed uniformly. As shown in FIG. 19, in a state where the elastic ring 180 is attached to the annular groove 161 a, the curvature center O 3 of the outer periphery of the elastic ring 180 coincides with the curvature center O 1 of the annular groove 161 a, and the outer periphery of the second holder main body 61 It is eccentric to the gear side in the third direction with respect to the curvature center O2 of the surface.

As in the first embodiment, the elastic ring 180 is attached to the annular groove 161a in a state where the first holder 40 is assembled to the second holder 160, whereby the first holder 40 is the second holder through the outer peripheral opening 65a. It is regulated to get out of 160. Thus, the first holder 40 and the second holder 160 are locked by the elastic ring 180.

When the elastic ring 180 is attached to the annular groove 161 a, a part of the elastic ring 180 protrudes radially outward from the outer peripheral surface of the second holder main body portion 161. In the deepest portion 161 b of the annular groove 161 a, the elastic ring 180 does not protrude from the outer peripheral surface of the second holder main body portion 161. On the other hand, the elastic ring 180 projects the most at the shallowest portion 161c.

When the holder 30 is assembled into the housing hole 3d of the gear case 3, a part of the elastic ring 180 projecting radially outward from the annular groove 161a is pushed radially inward and compressed. Thus, the elastic force of the elastic ring 180 to be compressed acts on the second holder 160. The elastic ring 180 is most compressed at the deepest portion 161c, and the amount of compression decreases toward the deepest portion 161b. For this reason, the second holder 160 is biased to the opposite gear side in the third direction so as to be separated from the worm wheel 1 by the compressed elastic ring 180. Thus, the holder 130 is elastically supported by the elastic force of the elastic ring 180 with respect to the accommodation hole 3d, as in the locking structure by the clip 80 in the first embodiment.

Further, the second holder main body portion 161 of the second holder 160 receives the elastic force of the elastic ring 180, and is pressed against the inner peripheral surface of the accommodation hole 3d. Therefore, the power steering apparatus 100 according to the second embodiment has the same effect as the effect achieved by the locking structure by the clip 80 in the first embodiment.

Next, a modification of the second embodiment will be described.

In the second embodiment, the wire diameter of the elastic ring 180 is formed uniformly, and the depth of the annular groove 161a is formed to change in the circumferential direction. On the other hand, the wire diameter of the elastic ring 180 may be changed in the circumferential direction to make the depth of the annular groove 161a uniform. Also in this case, the center of curvature O3 of the outer peripheral surface of the elastic ring 180 mounted in the annular groove 161a is eccentric to the center of curvature O2 of the outer peripheral surface of the second holder main body 161, as in the above embodiment. In this case, in order to press the second holder 160 toward the opposite gear side in the third direction and against the inner peripheral surface of the accommodation hole 3d, a portion of the elastic ring 180 where the wire diameter is larger is positioned on the gear side. Need to be attached to For this reason, although the assembly process becomes complicated, the same effect as the above-mentioned embodiment can be produced. Further, both the depth of the annular groove 161a and the wire diameter of the elastic ring 180 may be changed in the circumferential direction.

Moreover, since it is the same as that of the first embodiment, illustration and detailed description will be omitted, but the elastic ring 180 and / or the annular groove 161a is provided with a protruding portion 80a, and the holder 130 is elastically supported by the elastic ring 180. At the same time, the second holder 160 may be configured to be pressed against the inner peripheral surface of the housing hole 3d. In addition, the elastic ring 180 may be formed into an elliptical shape other than a perfect circular shape or any other shape.

According to the above second embodiment, the same effect as that of the first embodiment can be obtained.

Third Embodiment
Next, a third embodiment of the present invention will be described with reference to FIGS. Hereinafter, differences from the first embodiment will be mainly described, and the same components as those of the first embodiment are denoted by the same reference numerals and description thereof will be omitted.

In the third embodiment, as shown in FIGS. 20 and 21, the holder 230 moves the first holder 240 having the holding portion 242 for holding the second bearing 11 and the movement of the second bearing 11 toward the worm wheel 1. Between the first holder 240 and the second holder 260, a second holder 260 having a guide portion 62 for guiding is provided in a compressed state, and the second bearing 11 is directed to the worm wheel 1 via the first holder 240. And a spring 70 for biasing.

As shown in FIGS. 22 and 23, the first holder 240 has a plate-shaped first holder main body portion 241, a holding portion 242 provided on the first holder main body portion 241, and the outer periphery of the outer ring 11 a of the second bearing 11. It has an opening 243 for exposing a part of the surface, and a seat 245 on which one end of the spring 70 is seated. A central hole 41 b is formed in the first holder main body 241 as in the first embodiment.

The holding portion 242 is a single wall portion provided on the opposite gear side in the third direction than the second bearing 11 as shown in FIGS. 20 and 22. The holding portion 242 protrudes from the first holder main body portion 241 along the central axis of the second bearing 11. The holding portion 242 is formed in an arc shape in which the inner side in the radial direction corresponds to the outer ring 11a of the second bearing 11, and is formed in an arc shape in which the outer side corresponds to the inner peripheral surface of the accommodation hole 3d.

The opening portion 243 is provided in the circumferential direction of the holding portion 242. In the first holder 240, the holding portion 242 is formed in the range of about 120 °, and the remaining 240 ° is formed as the opening 243. The opening 243 is formed by cutting a part of the cylindrical wall in the circumferential direction so as to open to the inner and outer peripheral surfaces. In other words, in the first holder 40 of the first embodiment, the first holder 40 of the third embodiment connects the first opening 43a and the second opening 43b with an opening without providing the first holding portion 42a. It is formed in the following shape. Also in the opening 243 in the third embodiment, a part of the outer peripheral surface of the outer ring 11 a of the second bearing 11 held by the holding portion 242 is exposed to the outside.

The seating portion 245 is provided so as to be connected to the first holder main body portion 241 on the side opposite to the holding portion 242 in the first holder main body portion 41. The seating portion 245 is provided such that the position in the third direction is on the opposite side of the holding portion 242 with respect to the central axis of the second bearing 11. That is, the holding portion 242 is provided on the opposite gear side in the third direction with respect to the second bearing 11, and the seating portion 245 is provided on the gear side.

In the present embodiment, the spring 70 is supported by the spacer 266 described later so as to exert a biasing force in the first biasing direction. Therefore, as shown in FIGS. 23 and 26, the first holder 40 is provided with a single seating portion 245 on which the spring 70 exerting a biasing force in the first biasing direction is seated. The seating portion 245 may be provided with only the seating portion 245 corresponding to the direction in which the spring 70 is supported as shown in FIG. Further, like the first receiving surface 67 and the second receiving surface 68 of the first embodiment, the seating portion 245 exerts a biasing force in either of the first biasing direction and the second biasing direction of the spring 70. Even in this case, one end of the spring 70 may be configured to be seated.

As shown in FIGS. 24 and 25, the second holder 260 is connected to the disc-shaped second holder main body portion 261, the guide portion 62 provided on the second holder main body portion 261, and the guide portion 62. An auxiliary holding portion 262 for holding the second bearing 11 together with the holding portion 42 of the holder 40, a spacer portion 266 on which the intermediate portion 70c between the both

end portions

70a and 70b of the spring 70 is seated, and And a positioning protrusion 64 to be inserted.

The second holder main body portion 261 is formed on the opposite side in the axial direction of the passage hole 261a which allows the passage of the seating portion 245 of the first holder 240, the guide portion 62 and the auxiliary holding portion 262, and extends in the third direction. And a notch 267.

The passage hole 261 a communicates with the notch 267. The seat portion 245 of the first holder 240 is inserted into the notch 267 of the second holder body 261 through the passage hole 261a.

In the notch 267, a spring 70 is accommodated. As shown in FIGS. 25 and 26, the notch 267 is divided by a first wall surface 267a extending in the first biasing direction and a second wall surface 267b extending in the second biasing direction. The notch 267 can accommodate the spring 70 when exerting the biasing force in any of the first biasing direction and the second biasing direction.

The guide part 62 has the 1st guide part 62a and the 2nd guide part 62b similarly to the said 1st Embodiment. The first guide portion 62a and the second guide portion 62b respectively have a pair of guide surfaces 62c and 62d provided parallel to each other and claw

portions

62e and 62f. Also in the present embodiment, a part of the outer ring 11a of the second bearing 11 exposed through the opening 243 of the first holder 240 directly contacts the first guide portion 62a and the second guide portion 62b.

The auxiliary holding portion 262 is an arc-shaped wall portion provided on the gear side in the third direction with respect to the central axis of the second bearing 11. The second bearing 11 is held by the holding portion 242 of the first holder 240 and the auxiliary holding portion 262 of the second holder 260. The auxiliary holding portion 262 circumferentially connects the first guide portion 62a and the second guide portion 62b.

A holder opening 263 is provided between the first guide portion 62a and the second guide portion 62b in the circumferential direction opposite to the auxiliary holding portion 262. The holding portion 242 of the first holder 240 faces the inner peripheral surface of the accommodation hole 3 d through the holder opening 263 (see FIG. 26). As described above, also in the present embodiment, as in the first embodiment, the first holder 240 and the second holder 260 extend in the radial direction between the second bearing 11 and the inner peripheral surface of the accommodation hole 3d. Do not overlap. Thus, the holder 230 can be configured to be compact.

The spacer 266 is provided in the notch 267 so as to connect the first wall surface 267 a and the second wall surface 267 b which constitute the notch 267. The intermediate portion 70 c of the spring 70 housed in the notch 267 is seated in the spacer 266. The spacer 266 has a first spacer 266a perpendicular to the first biasing direction and a second spacer 266b perpendicular to the second biasing direction. The biasing direction of the spring 70 can be changed depending on whether the spring 70 is seated on the first spacer 266a or the second spacer 266b. Thus, in the third embodiment, the spacer 266 (first spacer 266a, second spacer 266b) biases the spring 70 in the first biasing direction and the second biasing direction. It corresponds to the support part (1st support part, 2nd support part) supported so that it may exert.

As shown in FIG. 26, one end 70a of the spring 70 is seated on the seating portion 245 of the first holder 240, and the other end 70b is seated on the inner circumferential surface of the accommodation hole 3d. The space between the one end 70 a and the middle 70 c of the spring 70 and the space between the other end 70 b and the middle 70 c are held in a compressed state. In the spring 70, since the intermediate portion 70c is seated on the spacer portion 266, the axial force acting on the one end 70a does not act on the other end 70b, and vice versa. Therefore, in the spring 70, one spring action is exhibited between the one end 70a and the middle part 70c, and one spring action is exhibited between the middle part 70c and the other end 70b. The spring action is apparent.

In the present embodiment, a biasing force that causes the holding portion 242 of the first holder 240 and the auxiliary holding portion 262 of the second holder 260 to approach each other acts by the spring 70 between the one end portion 70a and the middle portion 70c. Therefore, the holding portion 242 and the auxiliary holding portion 262 are pressed against the outer ring 11 a of the second bearing 11. Thereby, the 1st holder 240, the 2nd holder 260, and the 2nd bearing 11 are not separated but integrated. That is, a part between the one end 70 a and the middle portion 70 c of the spring 70 functions as a locking member for locking the first holder 240 and the second holder 260.

Further, the spring 70 between the one end portion 70 a and the middle portion 70 c exerts an urging force for urging the first holder 240 toward the gear side with respect to the second holder 260. Thus, the spring 70 also functions as a biasing member.

Furthermore, a part between the other end 70 b of the spring 70 and the middle portion 70 c exerts a function of elastically supporting the holder 230 with respect to the accommodation hole 3 d.

As described above, in the present embodiment, the biasing member and the locking member are integrally configured as one spring 70.

Here, as shown in FIG. 26, the spring 70 between the one end portion 70a and the middle portion 70c has an urging force in a direction toward the opposite gear side (hereinafter, referred to as "first urging force F1"). (2) It exerts on the holder 260. The spring 70 between the other end 70 b and the middle portion 70 c exerts an urging force in a direction toward the gear side (hereinafter, referred to as “second urging force F 2”) with respect to the second holder 260. When the first biasing force F1 is larger than the second biasing force F2, the second holder 260 is biased to move to the opposite gear side, so the worm shaft 2 is reliably directed to the gear side. It can not be energized. Therefore, in the holder 230, in order to bias the worm shaft 2 and the second bearing 11 toward the gear side, the second biasing force F2 is configured to be larger than the first biasing force F1. Specifically, the position of intermediate portion 70c of spring 70 seated on spacer portion 266 (in other words, the amount of compression between one end 70a and intermediate portion 70c and between the other end 70b and intermediate portion 70c) The shape and mounting structure of the spring 70 such as the pitch of the spring 70 and the winding diameter of the spring 70 are appropriately set, and the second biasing force F2 is configured to be larger than the first biasing force F1. As a result, the second holder 260 is prevented from moving to the opposite gear side, and the worm shaft 2 and the second bearing 11 can be more reliably urged toward the gear side.

In assembling the holder 230, first, the first holder 240 and the second holder 260 are combined such that the seating portion 245 of the first holder 240 passes through the passage hole 261a of the second holder 260. Also, the second bearing 11 is accommodated between the holding portion 242 of the first holder 240 and the auxiliary holding portion 262 of the second holder 260. Next, the intermediate portion 70c of the spring 70 is seated on the first space portion 266a, and the one end portion 70a is compressed by a predetermined amount to be seated on the seating portion 245. Thus, the holder 230 is assembled. In the third embodiment, unlike the first embodiment, the first holder 240 and the second holder 260 are assembled along the axial direction of the second bearing 11.

In order to assemble the holder 230 into the accommodation hole 3d, the holder 230 is accommodated in the accommodation hole 3d while the other end 70b of the spring 70 is compressed and compressed so that the positioning convex portion 64 is inserted into the positioning hole 3e. Thus, the holder 230 is elastically supported with respect to the accommodation hole 3d by the biasing force between the middle portion 70c and the other end 70b of the spring 70.

Also in the third embodiment as described above, since the second bearing 11 directly contacts the guide portion 62 of the second holder 260, the meshing accuracy of the worm wheel 1 and the worm shaft 2 is the same as the dimensional accuracy of the first holder 40. Not affected.

In addition, the functions of both the biasing member for biasing the second bearing 11 via the first holder 40 and the locking member for locking the first holder 40 and the second holder 60 are also included. In order to demonstrate, it is possible to reduce the number of parts.

In addition, since the spring 70 has the other end seated on the inner peripheral surface of the housing hole 3d, the spring 70 does not exert the function of pressing the second holder 60 against the inner peripheral surface of the housing hole 3d. It plays the same effect.

Hereinafter, the configuration, operation, and effects of the embodiment of the present invention will be collectively described.

The power steering apparatus 100 includes a worm shaft 2 rotating with the drive of the electric motor 7, a worm wheel 1 meshing with the worm shaft 2, a second bearing 11 rotatably supporting the tip end of the worm shaft 2, and a worm The gear case 3 for housing the shaft 2 and the

holders

30, 130, 230 disposed in the gear case 3 for housing the second bearing 11 are provided. The

holders

30, 130, 230 are configured to hold the second bearing 11

1st holder

40, 240, the

2nd holder

60, 160, 260 which has the guide part 62 which guides movement of the 2nd bearing 11 which goes to worm wheel 1,

1st holder

40, 240 and

2nd holder

60, 160, And a

first holder

40, 240 and a

second holder

60, 160. 260 having a supporting portion (supporting portion 50, spacer 266) for supporting the spring 70, the supporting (supporter 50, spacer 266) is biased in the first biasing direction To exert a biasing force in a second biasing direction different from the first biasing direction and a first support portion (the first support portion 51, the first spacer 266a) capable of supporting the spring 70 so as to exert And the second support portion (the second support portion 52, the second spacer portion 266b) capable of supporting the spring 70, and the spring 70 is the first support portion (the first support portion 51, the first support portion). It is supported by either the seat portion 266a) and the second support portion (the second support portion 52, the second space portion 266b).

In this configuration, the biasing member is provided between the

first holder

40, 240 and the

second holder

60, 160, 260, and the support portion (the support portion 50, the spacer portion 266) is the

first holder

40, 240 and It is provided in any of the

second holders

60, 160, 260. Also, depending on which of the first support portion (first support portion 51, first spacer portion 266a) and second support portion (second support portion 52, second spacer portion 266b) support the spring 70, The biasing direction by the spring 70 can be changed. As described above, since the biasing direction of the spring 70 can be changed by the configuration of the

holders

30, 130, 230, using the

common holder

30, 130, 230 for each of the left-hand drive car and the right-hand drive car It is not necessary to process the gear case 3 in order to make the device configuration common. Therefore, the manufacturing cost of power steering device 100 can be reduced.

In the power steering apparatus 100, the support portion 50 is provided in the first holder 40, the spring 70 is accommodated in the spring accommodation recess 55 provided in the support portion 50, and the spring accommodation recess 55 is divided by the first support portion 51. The first accommodation recess 56 and the second accommodation recess 56 are provided so as to intersect with each other. .

In the power steering apparatus 100, one of the first support portion 51 and the second support portion 52 not supporting the biasing member supports the biasing member on any one of the first holder 40 and the second holder 60. In this case, an erroneous assembly preventing portion is formed which inhibits the assembly of the first holder 40 and the second holder 60.

In this configuration, when the holder 30 is assembled, an error in the mounting direction of the biasing member can be easily detected.

In the power steering apparatus 100, the

first holder

40, 240 is formed with a central hole 41b for avoiding interference with the worm shaft 2, and the biasing member faces the central hole 41b to form a first support (first support It is supported by the part 51, the first spacer 266a) or the second support (the second support 52, the second spacer 266b).

In this configuration, even after assembling the

holders

30, 130, 230, an error in the assembling direction of the spring 70 is easily detected by confirming the biasing direction of the spring 70 by visual observation from the central hole 41b. can do.

Further, the present invention includes the following inventions.

holders

30, 130 and 230 housed in the housing holes 3d provided in the gear case 3 and for housing the second bearing 11 are provided. The

holders

30, 130 and 230 are the second bearings Of the second bearing 11 through the

openings

43 and 243, the

first holders

40 and 240 having the holding

portions

42 and 242 for holding the outer circumference of 11 and the

openings

43 and 243 for exposing a part of the outer circumference of the second bearing 11; Second holders 60, 16 having a guide portion 62 for guiding the movement of the second bearing 11 in contact with the outer periphery and heading toward the worm wheel 1. Has a 260, and a spring 70 for urging the second bearing 11 via the

first holder

40, 240 toward the worm wheel 1, the.

In this configuration, the second bearing 11 is in direct contact with the guide portion 62 of the

second holder

60, 160, 260 and guided to move. As described above, the second bearing 11 is not guided to move through the

first holder

40, 240, but is directly guided by the guide portion 62, so the dimensional accuracy of the

first holder

40, 240 is The influence on the meshing accuracy is suppressed. Therefore, in the power steering device 100, the meshing accuracy between the worm shaft 2 and the worm wheel 1 can be improved.

The power steering apparatus 100 has a holder opening 63 which allows the second bearing 11 and the holder 42 of the first holder 40 to pass in the direction in which the guide 62 guides the second bearing 11.

In this configuration, the second bearing 11 held by the first holder 40 can be inserted into the second holder 60 through the holder opening 63. Thereby, the assembling direction of the first holder 40 and the second bearing 11 to the second holder 60 coincides with the urging direction by the urging member (the moving direction of the second bearing 11), so that the assembling property is improved. Do.

In the power steering apparatus 100, the holding

portions

42, 242 of the

first holders

40, 240 face the inner peripheral surface of the accommodation hole 3d through the

holder openings

63, 263.

In this configuration, the holding

portions

42 and 242 of the

first holders

40 and 240 are not in contact with the

second holders

60 and 260 to restrict their movement, and directly face the inner peripheral surface of the housing hole 3d. Therefore, the dimensional accuracy of the

second holder

60 and 260 in the moving direction of the second bearing 11 is prevented from affecting the meshing accuracy between the worm shaft 2 and the worm wheel 1. Therefore, the meshing accuracy can be further improved.

In the power steering apparatus 100, the guide portions 62 of the second holder 60 each have

guide surfaces

62c and 62d provided in parallel with each other with the central axis of the second bearing 11 in contact with the outer peripheral surface of the second bearing 11. A first holder opening 63a is formed between the first guide 62a and the second guide 62b, and the holder opening 63 of the second holder 60 is provided between the first guide 62a and the second guide 62b in the circumferential direction. The holding portion 42 of the first holder 40 includes a first holding portion 42a and a second holding portion 42b which are provided to face each other with the central axis of the second bearing 11 interposed therebetween. The first holding portion 42a and the second holding portion 42b respectively surround the first guide portion 62a and the second guide portion 62b through the first opening 43a and the second opening 43b, respectively. It is arranged in the direction.

In this configuration, the configuration of the first holder 40 and the configuration of the second holder 60 do not overlap in the radial direction of the second bearing 11 between the second bearing 11 and the inner peripheral surface of the accommodation hole 3 d. Can be configured compactly.

In power steering apparatus 100, spring 70 is held in a compressed state between first holder 40 and second holder 60.

In the power steering apparatus 100, the first holder 40 has a support portion 50 provided in line with the holding portion 42 in the axial direction of the second bearing 11 to support the spring 70, and the second holder 60 is a second bearing 11 The spring 70 is provided between the support portion 50 of the first holder 40 and the reception portion 65 of the second holder 60. It is held in a compressed state.

In these configurations, the spring 70 is provided axially in line with the second bearing 11 and biases the second bearing 11 in the radial direction. For this reason, the configuration of the power steering apparatus 100 can be made compact in the radial direction of the second bearing 11.

The power steering apparatus 100 includes a worm shaft 2 rotating with the drive of the electric motor 7, a worm wheel 1 meshing with the worm shaft 2, a second bearing 11 rotatably supporting the tip end of the worm shaft 2, and a worm The gear case 3 is provided with a housing hole 3d for housing the shaft 2, and the

holders

30, 130, 230 housed in the housing hole 3d provided in the gear case 3 for housing the second bearing 11, and the

holders

30, 130, 230 is a

first holder

40, 240 for holding the second bearing 11, a

second holder

60, 160, 260 having a guide portion 62 for guiding the movement of the second bearing 11 toward the worm wheel 1, and a

first holder

40, 240 and the

second holders

60, 160, 260 in a compressed state, and the first The second holder 60 passes the second bearing 11 and the

first holder

40, 240 in the direction in which the guide portion 62 guides the second bearing 11. The

first holder

40, 240 has an

acceptable holder opening

63, 263, and the

first holder

40, 240 faces the inner circumferential surface of the accommodation hole 3 d through the

holder opening

63, 263.

In this configuration, the first holders 40 and 140 face the inner peripheral surface of the accommodation hole 3 d through the

holder openings

63 and 263 of the

second holders

60, 160 and 260. As described above, since the first holders 40 and 140 and the

second holders

60, 160 and 260 do not overlap in the direction in which the guide portion 62 guides, the

holders

30, 130 and 230 should be compact. Can. Therefore, the power steering device 100 can be miniaturized.

In the power steering apparatus 100, the

holders

30, 130, 230 further have locking members (clip 80, elastic ring 180, spring 70) for locking the first holder 40 and the second holder 60, and the locking members The clip 80, the elastic ring 180 and the spring 70 elastically support the

holders

30, 130, 230 with respect to the accommodation hole 3d.

In this configuration, the holding force of the holder 30 with respect to the accommodation hole 3d is secured by the locking members (clip 80, elastic ring 180, and spring 70), so the number of parts can be reduced.

In the power steering apparatus 100, the

second holders

60 and 160 are urged in the direction away from the worm wheel 1 by the locking members (clip 80, elastic ring 180) and pressed against the inner circumferential surface of the accommodation hole 3d.

In this configuration, the biasing force of the spring 70 is not affected by the elastic force of the locking member (the clip 80 and the elastic ring 180), so that the biasing force of the spring 70 can be stabilized.

In the power steering apparatus 100, the second holder 60 has a groove 61a extending in an arc shape on the outer peripheral surface, and the locking member is an arc-shaped clip 80 accommodated in the groove 61a.

In the power steering device 100, the wire diameter of the clip 80 changes in the circumferential direction.

In the power steering device 100, the groove 61a changes in depth in the circumferential direction.

In the power steering device 100, at least one of the groove portion 61a and the clip 80 is provided with a raised portion 80a that bulges the clip 80 radially outward.

In the power steering apparatus 100, the clip 80 has a pair of arc portions 80b formed in an arc shape, and a linear connection portion 80c connecting the pair of arc portions 80b.

In the power steering apparatus 100 according to the second embodiment, the second holder 160 has an annular groove 161a on the outer peripheral surface, and the locking member is an annular elastic ring 180 accommodated in the annular groove 161a.

In the power steering device 100 according to the second embodiment, the annular groove 161a changes in depth in the circumferential direction.

In the power steering apparatus 100 according to the third embodiment, the biasing member and the locking member are configured as a spring 70 integrally formed, and one end 70 a of the spring 70 is seated on the first holder 240. The end 70b is seated on the inner peripheral surface of the accommodation hole 3d, and the first holder 240 has a holding portion 242 for holding the second bearing 11 and a seating portion 245 on which the one end 70a of the spring 70 is seated. The second holder 260 includes an auxiliary holding portion 262 for holding the second bearing 11 together with the holding portion 242, and a spacer 266 on which the intermediate portion 70c between the one end 70a and the other end 70b of the spring 70 is seated. , And the holding portion 242 and the auxiliary holding portion 262 are pressed against the second bearing 11 by the biasing force between the one end portion 70a and the middle portion 70c of the spring 70, and the first holder 2 0 and the second holder 260 are locked to each other.

In this configuration, since the spring 70 exerts the functions of both the biasing member and the locking member, the number of parts can be reduced.

As mentioned above, although the embodiment of the present invention was described, the above-mentioned embodiment showed only a part of application example of the present invention, and in the meaning of limiting the technical scope of the present invention to the concrete composition of the above-mentioned embodiment. Absent.

In each of the above embodiments, the worm wheel 1 is provided on the output shaft of the steering shaft. Instead of this configuration, the worm wheel 1 may be provided on a pinion shaft provided separately from the steering shaft and meshing with the rack shaft.

The present application claims priority based on Japanese Patent Application No. 2017-167733 filed on Aug. 31, 2017 to the Japanese Patent Office, and the entire contents of this application are incorporated herein by reference.

Claims

A power steering device,
A worm shaft that rotates with the drive of the electric motor,
A worm wheel meshing with the worm shaft;
A bearing rotatably supporting an end side of the worm shaft;
A gear case accommodating the worm shaft;
A holder disposed in the gear case and accommodating the bearing;
The holder is
A first holder for holding the bearing;
A second holder having a guide for guiding the movement of the bearing towards the worm wheel;
An urging member provided in a compressed state between the first holder and the second holder;
A support portion provided on any one of the first holder and the second holder to support the biasing member;
The support portion is
A first support portion capable of supporting the biasing member so as to exert a biasing force in a first biasing direction;
A second support portion capable of supporting the biasing member to exert a biasing force in a second biasing direction different from the first biasing direction;
The power steering device, wherein the biasing member is supported by any one of the first support portion and the second support portion.
The power steering apparatus according to claim 1,
The support portion is provided to the first holder,
The biasing member is housed in a spring housing recess provided in the support portion,
The spring receiving recess includes a first receiving recess defined by the first support, and a second receiving recess defined by the second support.
The power steering device is provided such that the first accommodation recess and the second accommodation recess cross each other.
The power steering apparatus according to claim 1,
When one of the first support portion and the second support portion that does not support the biasing member supports any one of the first holder and the second holder when the biasing member is supported, A power steering apparatus, wherein an erroneous assembly preventing portion is formed which hinders the assembly of the first holder and the second holder.
The power steering apparatus according to claim 1,
The first holder is formed with a central hole for avoiding interference with the worm shaft;
The power steering device, wherein the biasing member faces the central hole and is supported by the first support portion or the second support portion.