JP2019043336A - Power steering device - Google Patents

Abstract

To reduce manufacturing costs of a power steering device.SOLUTION: A power steering device 100 includes: a bearing 11 which rotatably supports the tip side of a worm shaft 2; a gear case 3 which houses the worm shaft 2; and a holder 30 which is disposed in the gear case 3 and houses the bearing 11. The holder 30 has: a first holder 40 which holds the bearing 11; a second holder 60 having a guide part 62 which guides movement of the bearing 11 moving toward 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 at the first holder 40 and supports the spring 70. The support part 50 has: a first support part 51 which can support the spring 70 so that a biasing force is applied in a first biasing direction; and a second support part 52 which can support the spring 70 so that a biasing force is applied in a second biasing direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power steering apparatus.

  In Patent Document 1, both ends of a worm gear driven by an electric motor are pivotally supported by bearings provided in a gear housing, and 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 is disclosed. An electric power steering device having preload means for urging the bearing of the worm gear in a predetermined preload direction so as to apply preload to the motor is disclosed.

  In this electric power steering apparatus, the worm gear is supported so as to be swingable around the bearing on one end side, and the bearing on the other end side is urged in a predetermined preload direction by the preload means. The preload means includes a bearing case, a seat rubber, and a spring. The cylindrical protrusion of the bearing case is loaded into a rubber loading hole provided in the gear housing, and a seat rubber containing a spring is loaded into the rubber loading hole. In the preload means, the preload direction for biasing the bearings 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 when the worm gear rotates in the right steering direction. In addition, it is set in the radial direction passing through the central axis of the worm gear within the range of the sub-angle between the direction of the radial component of the driving reaction force received from the worm wheel.

JP 2013-208933 A

  In power steering devices, it is required to make the configuration common to left-hand drive vehicles and right-hand drive vehicles in order to reduce manufacturing costs.

  As described in Patent Document 1, in a power steering device including a mechanism for reducing backlash by urging the worm shaft, the twist direction of the worm gear differs between the left-hand drive vehicle and the right-hand drive vehicle. The urging direction of the urging spring is also different. Since the power steering device described in Patent Document 1 has a structure in which a spring is accommodated in a hole formed in a gear case, in order to make the device configuration common to a left-hand drive vehicle and a right-hand drive vehicle, a relatively large component is used. Processing such as forming a hole corresponding to the urging direction in a certain gear case must be performed, which may increase the manufacturing cost.

  The present invention has been made in view of such technical problems, and an object thereof is to reduce the manufacturing cost of a power steering device.

  A first invention is a power steering device, which is a worm shaft that rotates as the electric motor is driven, a worm wheel that meshes with the worm shaft, a bearing that rotatably supports the tip side of the worm shaft, and a worm shaft. And a holder disposed in the gear case for housing the bearing, the holder having a first holder for holding the bearing and a second guide portion for guiding the movement of the bearing toward the worm wheel. A holder, a biasing member provided in a compressed state between the first holder and the second holder, and a support portion provided in any one of the first holder and the second holder for supporting the biasing member. A first support portion capable of supporting the biasing member so as to exert a biasing force in the first biasing direction, and a biasing force in a second biasing direction different from the first biasing direction. And a second supporting portion capable of supporting a biasing member to volatilizing, biasing member may be supported by either the first support and the second support.

  In the first invention, the urging member is provided between the first holder and the second holder, and the support portion is provided in either the first holder or the second holder. Further, the urging direction by the urging member can be changed depending on which of the first supporting portion and the second supporting portion supports the urging member. As described above, since the urging direction of the urging member can be changed depending on the configuration of the holder, a common holder can be used for each of the left-hand drive vehicle and the right-hand drive vehicle, and the device configuration can be shared. Therefore, there is no need to process the gear case.

  The second invention is characterized in that the first support part and the second support part are provided in the first holder.

  According to a third aspect of the present invention, when one of the first support part and the second support part that does not support the urging member is supported by one of the first holder and the second holder, A misassembly prevention unit that inhibits assembly of the first holder and the second holder is formed.

  In the third invention, it is possible to easily detect an error in the assembly direction of the urging member when the holder is assembled.

  According to a fourth aspect of the present invention, the first holder is formed with a central hole that avoids interference with the worm shaft, and the biasing member is supported by the first support part or the second support part facing the central hole. It is characterized by.

  In the fourth invention, even after the holder is assembled, an error in the assembly direction of the urging member can be easily detected by confirming the urging direction of the urging member by visual inspection from the central hole. Can do.

  According to the present invention, the manufacturing cost of the power steering device can be reduced.

It is a lineblock diagram of the power steering device concerning a 1st embodiment of the present invention. It is sectional drawing which shows the power steering apparatus which concerns on 1st Embodiment of this invention. It is a perspective view of the holder concerning a 1st embodiment of the present invention. It is a front side perspective view of the 1st holder which concerns on 1st Embodiment of this invention. It is a back side perspective view of the 1st holder concerning a 1st embodiment of the present invention. It is a front side perspective view of the 1st holder and bearing concerning a 1st embodiment of the present invention. It is a front side perspective view of the 2nd holder which concerns on 1st Embodiment of this invention. It is a back side perspective view of the 2nd holder concerning a 1st embodiment of the present invention. It is sectional drawing along the IX-IX line in FIG. It is sectional drawing along the XX line in FIG. It is a top view of the clip concerning a 1st embodiment of the present invention. It is sectional drawing which shows the state in which the holder which concerns on 1st Embodiment of this invention was integrated in the gear case. It is a perspective view explaining the assembly procedure of the holder which concerns on 1st Embodiment of this invention, and shows the process of assembling a 1st holder, a bearing, and a spring. It is a perspective view explaining the assembly procedure of the holder which concerns on 1st Embodiment of this invention, and shows the process of assembling a 2nd holder and a clip. It is sectional drawing which shows the 1st modification of the holder which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the 2nd modification of the holder which concerns on 1st Embodiment of this invention. It is a figure which shows the 3rd modification of the holder which concerns on 1st Embodiment of this invention, and is a top view which shows the modification of a clip. It is sectional drawing which shows the 2nd holder which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the 2nd holder and elastic ring which concern on 2nd Embodiment of this invention. It is a front side perspective view which shows the holder which concerns on 3rd Embodiment of this invention. It is a back side perspective view showing a holder concerning a 3rd embodiment of the present invention. It is a front side perspective view which shows the 1st holder which concerns on 3rd Embodiment of this invention. It is a back side perspective view showing the 1st holder concerning a 3rd embodiment of the present invention. It is a front side perspective view which shows the 2nd holder which concerns on 3rd Embodiment of this invention. It is a back side perspective view showing the 2nd holder concerning a 3rd embodiment of the present invention. It is sectional drawing which shows the state in which the holder which concerns on 3rd Embodiment of this invention was integrated in the gear case.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
With reference to FIGS. 1-17, the power steering apparatus 100 which concerns on 1st Embodiment of this invention is demonstrated.

  The power steering device 100 is a device that is mounted on a vehicle and assists a steering force applied by a driver to a steering wheel.

  As shown in FIGS. 1 and 2, the power steering device 100 is connected to the output shaft of the electric motor 7 and rotates with the drive of the electric motor 7, meshes with the worm shaft 2, and rotates the wheel 6. A worm wheel 1 for transmitting the rotational force of the electric motor 7 to the rack shaft 8 to be steered. The worm shaft 2 rotates as the electric motor 7 is driven, 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 speed reducer.

  As shown in FIG. 1, a steering shaft 20 is connected to the steering handle 10, and the steering shaft 20 rotates as the steering handle 10 rotates. The steering shaft 20 includes an input shaft 21 linked to the steering handle 10, an output shaft 22 linked to the rack shaft 8, and a torsion bar 23 connecting 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 that detects a steering torque that acts on the torsion bar 23 by the relative rotation of the input shaft 21 and the output shaft 22 that accompanies the steering operation by the driver, and the steering that is detected by the torque sensor 24. And a controller 25 that controls the driving of the electric motor 7 based on the torque. 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 assist torque. As described above, the power steering apparatus 100 assists the driver's steering operation by controlling the drive of the electric motor 7 by the controller 25 based on the detection result of the torque sensor 24.

  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 that surrounds the worm shaft 2 and a bottom wall 3 c that faces the tip of the worm shaft 2. The peripheral wall 3b and the bottom wall 3c are integrally formed. Thus, since the gear case 3 is not a configuration in which the opening 43 at the bottom is sealed with a lid, but has a bag-like structure, the gear case 3 is excellent in waterproofness. The gear case 3 may be made of resin. The gear case 3 may have a structure in which the opening end portion of the peripheral wall 3b is sealed with a lid instead of the integrated structure of the peripheral wall 3b and the bottom wall 3c.

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

  The base 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 sandwiched between a step portion 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 sandwiched between the step 2 b of the worm shaft 2 and the joint 9 that is press-fitted into the end of the worm shaft 2. Thereby, the movement to the axial direction of the worm shaft 2 is controlled.

  The tip end side of the worm shaft 2 is rotatably supported by the 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 the holder 30, and the holder 30 is disposed in the accommodation hole 3 d having a circular inner peripheral surface formed on the bottom side of the gear case 3.

  Hereinafter, a specific configuration of the holder 30 will be described.

  In the following, as shown in FIG. 2, the direction along the central axis of the worm shaft 2 (the central axis of the second bearing 11) (the left-right direction in FIG. 2) is the “first direction”, and the center of the worm wheel 1. A direction along the axis (vertical direction in FIG. 2) is a “second direction”, and a direction perpendicular to both the central axis of the worm shaft 2 and the central axis of the worm wheel 1 (up and down direction in FIG. 2) is “third direction”. Also referred to as “direction”. That is, the first direction, the second direction, and the third direction are directions along three orthogonal axes that are orthogonal to each other. Further, in the third direction, one side (upper side in FIG. 2) on the worm wheel 1 side when 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 the “non-gear side”.

  2 and 3, the holder 30 includes a first holder 40 having a holding portion 42 that holds the second bearing 11 and a guide portion that guides the movement of the second bearing 11 toward the worm wheel 1. And a coil spring (hereinafter simply referred to as “spring”) 70 as a biasing member that biases the second bearing 11 toward the worm wheel 1 via the first holder 40. And an arcuate clip 80 as a locking member that locks and integrates 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 FIGS. 4 to 6, the first holder 40 includes a plate-like first holder main body 41, a holding portion 42 provided in the first holder main body 41, and one of the outer peripheral surfaces of the second bearing 11. An opening 43 that exposes the portion, and a support portion 50 in which a spring accommodating recess 55 that accommodates the spring 70 is formed.

  The 1st holder main-body part 41 is formed in the plate shape which has what is called a double-sided width shape in which a pair of parallel surface mutually parallel was formed. The first holder main body 41 includes a circular recess 41a provided in the center, and a central hole 41b formed in the bottom of the recess 41a and penetrating the first holder main body 41 in the thickness direction (first direction). Have.

  As shown in FIG. 2, the recess 41a is provided so as to face the inner ring 11b of the second bearing 11, and has a larger inner diameter than the inner ring 11b. The contact between the inner ring 11b of the second bearing 11 and the first holder body 41 is avoided by the recess 41a. Thereby, the rotation of the inner ring 11b of the second bearing 11 is not hindered by the first holder 40, and the worm shaft 2 can smoothly rotate.

  The central hole 41b is formed with an inner diameter larger than the diameter of the end portion of the worm shaft 2 supported by the second bearing 11, and a part of the end portion of the worm shaft 2 is inserted therethrough. The end of the worm shaft 2 passes through the first holder main body 41 of the holder 30, so that the power steering device 100 can be reduced in size in the axial direction of the worm shaft 2.

  As shown in FIGS. 4 to 6, the holding portion 42 includes a first holding portion 42 a and a second holding portion 42 b that are provided to face each other across the central axis of the second bearing 11. The first holding part 42a and the second holding part 42b are provided so as to protrude in the same direction from the first holder main body part 41 along the central axis of the second bearing 11 (along the first direction). The first holding part 42a and the second holding part 42b face each other in the third direction. The first holding part 42a and the second holding part 42b are formed in an arc shape corresponding to the outer ring 11a of the second bearing 11 on the radially inner side and formed in an arc shape corresponding to the inner peripheral surface of the accommodation hole 3d. The The 1st holding | maintenance part 42a and the 2nd holding | maintenance part 42b hold | maintain a part of outer peripheral surface of the outer ring | wheel 11a of the 2nd bearing 11 accommodated in the inner side. As for the 1st holding | maintenance part 42a and the 2nd holding | maintenance part 42b, the 1st holding | maintenance part 42a is relatively provided in the gear side, and the 2nd holding | maintenance part 42b is relatively provided in the non-gear side.

  The opening 43 includes a first opening 43 a and a second opening 43 b that are partitioned by the first holding part 42 a and the second holding part 42 b 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 space inside the first holding part 42 a and the second holding part 42 b that accommodates the second bearing 11. As a result, as shown in FIG. 6, the first opening 43a and the second opening 43b are a part of the outer peripheral surface of the outer ring 11a of the second bearing 11 held by the first holding part 42a and the second holding part 42b. Part is exposed to the outside.

  The support part 50 is provided in the surface on the opposite side to the holding | maintenance part 42 in the 1st holder main-body part 41, as shown in FIG. The support part 50 is formed in a two-plane width shape in which a cross section perpendicular to the first direction has a pair of parallel surfaces (see FIG. 10). The support portion 50 has a spring accommodating recess 55 that accommodates the spring 70. The spring 70 is provided on the opposite side of the first holder body 41 from the second bearing 11 held by the first holding part 42a and the second holding part 42b. Therefore, the spring 70 is provided so as to be aligned 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. And a holder opening 63 that allows the second bearing 11 to pass therethrough, and a positioning protrusion 64 that is inserted into a positioning hole 3e (see FIG. 2) provided in the bottom wall 3c of the housing hole 3d of the gear case 3.

  The 2nd holder main-body part 61 has the receiving part 65 which accommodates the support part 50 of the 1st holder 40, and the circular-arc-shaped groove part 61a extended in the circumferential direction and formed in an outer peripheral surface.

  The receiving portion 65 is a recess having an outer peripheral opening 65 a that opens on the outer peripheral surface of the second holder main body 61 on the gear side in the third direction. Further, the receiving portion 65 opens on one end surface 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 65a. The receiving part 65 supports the spring 70 between the support part 50 of the 1st holder 40 (refer FIG. 10).

  As shown in FIG. 8, the groove 61a is a C-shaped arc groove whose both ends are separated in the circumferential direction by a partition wall 61b. 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 divided into two by the outer peripheral opening 65a. The partition wall portion 61b is provided on the opposite side of the third direction across the central axis of the second bearing 11 with respect to the outer peripheral opening portion 65a.

  As shown in FIGS. 7 to 9, the guide part 62 includes a first guide part 62 a and a second guide part 62 b that are opposed to each other with the second bearing 11 interposed therebetween. The first guide part 62a and the second guide part 62b are formed to protrude in the same direction from the second holder main body part 61 along the central axis of the second bearing 11 (see FIGS. 7 and 8). In FIG. 9, the second bearing 11 is simplified.

  A pair of guide surfaces 62c and 62d, which are flat surfaces extending in the third direction and parallel to each other, are formed on the first guide portion 62a and the second guide portion 62b. The distance between the pair of guide surfaces 62c and 62d is formed slightly larger than the outer diameter of the outer ring 11a of the second bearing 11. As for the 2nd bearing 11, the outer peripheral surface of the outer ring | wheel 11a contacts a pair of guide surface 62c, 62d, and the movement along the 3rd direction toward the worm hole 1 is guided by a pair of guide surface 62c, 62d.

  The length (the length in the first direction) that the first guide portion 62a and the second guide portion 62b protrude from the second holder main body portion 61 is formed to be larger than the thickness (the axial length) of the second bearing 11. Is done. Further, as shown in FIG. 7, claw portions 62 e and 62 f extending toward the central axis of the second bearing 11 are formed at the tips of the first guide portion 62 a and the second guide portion 62 b. The claw portions 62e and 62f prevent the second bearing 11 held by the first holder 40 from falling off from the first holder 40 in the axial direction (first direction) (see FIG. 3).

  As shown in FIG. 7, the holder opening 63 includes a first holder opening 63 a and a second holder opening 63 b that are partitioned by the first guide portion 62 a and the second guide portion 62 b in the circumferential direction of the second bearing 11. Become. That is, in the 2nd holder 60, the 1st holder opening part 63a and the 2nd holder opening part 63b are formed so that it may notch between the circumferential directions of the 1st guide part 62a and the 2nd guide part 62b. The first holder opening 63a and the second holder opening 63b are provided such that 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. Provided on the gear side. The first holder opening 63a and the second holder opening 63b pass through the first holding part 42a and the second holding part 42b of the first holder 40 and the second bearing 11 held by the first holder 40, respectively. Is acceptable.

  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 part 42 a and the second holding part 42 b of the first holder 40 are the second holder 60. Through the first holder opening 63a and the second holder opening 63b (see FIGS. 7 and 8), the second guide 11 is adjacent to the first guide 62a and the second guide 62b in the circumferential direction. In other words, the first guide portion 62a and the second guide portion 62b of the second holder 60 pass through the first opening 43a and the second opening 43b (see FIG. 4) of the first holder 40 to surround the second bearing 11. In the direction, it is adjacent to the first holding part 42a and the second holding part 42b. More specifically, 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 accommodation hole 3d of the gear case 3, respectively. Thereby, between the radial direction of the 2nd bearing 11 and the accommodation hole 3d, the 1st holder 40 and the 2nd holder 60 are provided so that it may not mutually overlap. Therefore, the holder 30 can have a compact configuration 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 away from the central axis of the second bearing 11 in the radial direction. The positioning convex portion 64 is fitted into the positioning hole 3e (see FIG. 2) formed in the bottom wall 3c of the accommodation hole 3d with a gap. 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.

  As shown in FIG. 10, 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. The spring 70 exerts an urging force such that the first holder 40 and the second holder 60 are separated from each other along the third direction. Accordingly, the spring 70 biases the second bearing 11 in a direction in which the gap between the tooth portion 2a of the worm shaft 2 and the tooth portion of the worm wheel 1 is reduced. That is, the spring 70 urges 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.

  As shown in FIGS. 10 and 11, the clip 80 is a metal C-shaped member having a circular cross section. The clip 80 is attached to the groove 61 a over the outer peripheral opening 65 a of the receiving portion 65. Thereby, the second bearing 11 and the first holder 40 are prevented from dropping from the second holder 60 through the outer peripheral opening 65a and the first holder opening 63a of the receiving portion 65 by the urging force of the spring 70. In this way, the first holder 40 and the second holder 60 are locked by the clip 80.

  In the present specification, the first holder 40 and the second holder 60 are locked when the holder 30 is not attached to the housing hole 3d of the gear case 3 due to the biasing force of the spring 70. This indicates a state in which the holder 40 is prevented from coming out (separated) from the inside of the second holder 60.

  As shown in FIG. 10, 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. Therefore, in a state where the first holder 40 and the second holder 60 are locked by the clip 80, the support portion 50 can move in the third direction between the clip 80 and the receiving portion 65. That is, in a state where the holder 30 is not assembled to the accommodation hole 3d, the first holder 40 is in a state where the support portion 50 is in contact with the clip 80, and the support portion 50 is on the inner peripheral surface of the receiving portion 65 of the second holder 60. It is possible to move in the third direction between the contact 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 the 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 the first guide portion. 62a and the guide surfaces 62c and 62d of the 2nd guide part 62b are contacted. 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. Thus, in this embodiment, the metal 2nd bearing 11 and the resin 2nd holder 60 contact with a hardness difference.

  As described above, in the holder 30, since the second bearing 11 is in direct contact with the guide portion 62, the dimensional accuracy of the first holder 40 is suppressed from affecting the meshing accuracy between the worm wheel 1 and the worm shaft 2. Can do.

  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 spring 70 so as to exert a biasing force in a first biasing direction inclined with respect to the third direction in which the second bearing 11 is guided by the guide portion 62. And a second support capable of supporting the spring 70 so as to exert an urging force in a second urging direction different from the first urging direction while being inclined with respect to the third direction. Part 52.

  The spring accommodating recess 55 opens to the side opposite to the gear in the third direction and opens to the end surface 50a of the support portion 50 perpendicular to the first direction. The central hole 41 b of the first holder body 41 opens into the spring accommodating recess 55.

  The spring accommodating recess 55 includes a first accommodating recess 56 capable of accommodating a spring 70 that exerts an urging force in the first urging direction, and a first accommodating portion that can accommodate the spring 70 so as to exert an urging force in the second urging direction. 2 containing recesses 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 with respect to the reference plane M parallel to the third direction. It is done. The first receiving recess 56 and the second receiving recess 57 are provided so as to intersect with each other. The first housing recess 56 and the second housing recess 57 intersect each other at a position facing the central hole 41b.

  The first support portion 51 includes a first seating surface 51a perpendicular to the first urging direction, planar first side wall surfaces 51b and 51c extending in the first urging direction, and a cross section perpendicular to the first urging direction. Has a first peripheral wall surface 51d formed in an arc shape. One first side wall surface 51 b is formed from 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 defined by the second support portion 52. The first peripheral wall surface 51d is connected to the first seating surface 51a and the first side wall surfaces 51b and 51c, respectively. The spring 70 housed in the first housing recess 56 is restricted by the first support part 51 from being inclined with respect to the first biasing direction.

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

  As shown in FIG. 10, the receiving portion 65 of the second holder 60 includes a first receiving surface 67 perpendicular to the first urging direction and a second receiving surface 68 perpendicular to the second urging direction. The spring 70 supported by the first support portion 51 is seated on the first receiving surface 67. The spring 70 supported by the second support portion 52 is seated on the second receiving surface 68. Note that the shape of the receiving portion 65 is not limited to this, as long as 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 arcuate surfaces that are continuous with each other.

  The opening of the spring accommodating 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. As a result, the spring 70 supported by the first support portion 51 or the second support portion 52 has the first side wall surfaces 51b and 51c or the second side wall surfaces 52b and 52c and the first peripheral wall surface from four directions around the central axis. 51d or the second peripheral wall surface 52d and the side surface 65b of the receiving portion 65 are surrounded. Therefore, the spring 70 is stably supported.

  In addition, the support portion 50 is provided with a protrusion 58 as an erroneous assembly preventing portion that prevents erroneous assembly in which the spring 70 is assembled in an erroneous urging direction. In the present embodiment, since the spring 70 is supported by the first support portion 51, the protrusion 58 is provided so as to protrude in the first direction from the second peripheral wall portion 52 d of the second support portion 52, as shown in FIG. 10. . As a result, when the spring 70 that should originally be supported by the first support part 51 is supported by the second support part 52, the spring 70 is lifted from the second peripheral wall surface 52 d by the protrusion 58, and the end face of the support part 50 A part of the spring 70 protrudes from 50a. In this state, the support portion 50 cannot be inserted into the receiving portion 65 together with the spring 70, and the first holder 40 and the second holder 60 cannot be assembled, so that erroneous assembly can be detected. . As described above, when the spring 70 is supported by the second support portion 52 that originally does not support the spring 70 by the protrusion 58, the assembly of the first holder 40 and the second holder 60 is obstructed, and erroneous assembly is prevented. 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 51 d of the first support portion 51. The protrusion 58 is not limited to the first peripheral wall surface 51d or the second peripheral wall surface 52d, but is provided on the first and second seating surfaces 51a and 52a, and the first and second side wall surfaces 51b, 51c, 52b, and 52c. Also good. In order for the protrusion 58 to increase the floating amount of the spring 70 and prevent erroneous assembly more reliably, the protrusion 58 is located as far as possible from the first and second seating surfaces 51a and 52a, for example, in 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 protrusion 58 is not limited to the first holder 40 and may be provided on 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 direction of rotation of the worm shaft 2. For this reason, in order to apply an appropriate biasing force to the meshing portion of the worm shaft 2 and the worm wheel 1 against the reaction force from the worm wheel 1, the spring 70 is arranged in the axial direction between the worm wheel 1 and the worm shaft 2 ( It is desirable to dispose the worm shaft 2 so as to be inclined with respect to the third direction).

  On the other hand, the configuration of the power steering device 100 is different depending on whether it is mounted on a right-hand drive vehicle or a left-hand drive vehicle. Specifically, since the inclination angle of the output shaft 22 with respect to the rack shaft 8 is reversed with respect to the vehicle center, the twist directions of the worm wheel 1 are opposite to each other. For this reason, the direction of the appropriate biasing force that the spring 70 applies to the meshing portion is different between the right-hand drive vehicle and the left-hand drive vehicle.

  On the other hand, in this embodiment, the spring 70 is selectively supported by the first support portion 51 and the second support portion 52. The 1st support part 51 and the 2nd support part 52 can support the spring 70 so that urging | biasing force can be exhibited in two directions, the 1st urging | biasing direction and the 2nd urging | biasing direction. For this reason, the first urging direction is a direction that exerts an appropriate urging force on the meshing portion in the right-hand drive vehicle, and the second urging direction is a direction that exerts an appropriate urging force on the meshing portion in the left-hand drive vehicle. Thus, regardless of whether the power steering device 100 is mounted on either a right-hand drive vehicle or a left-hand drive vehicle, 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 shared, and the manufacturing cost can be reduced. As described above, even when the protrusion 58 is provided as the misassembly preventing portion, the mold itself can be shared because a mold for forming the protrusion 58 may be inserted into the mold. Therefore, manufacturing cost can be reduced even when the protrusion 58 is formed as a misassembly prevention portion.

  Moreover, the 1st accommodation recessed part 56 and the 2nd accommodation recessed part 57 cross | intersect in the position which opposes the center hole 41b. For this reason, the spring 70 is supported so as to face the central hole 41b regardless of whether the spring 70 is supported by the first support part 51 or the second support part 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. ) The direction is visible. Thereby, even after the assembly of the holder 30, it can be easily confirmed whether the spring 70 is supported by the first support part 51 or the second support part 52. Thus, by confirming the urging direction of the spring 70, it is possible to easily confirm whether the vehicle handle position and the urging direction of the spring 70 are an appropriate combination, thereby preventing erroneous assembly.

  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 of the groove 61a of the second holder 60 is slightly larger than the wire diameter of the clip 80 and is uniform in the circumferential direction. The curvature radius R1 (see FIG. 10) of the bottom of the groove 61a is formed larger than the curvature radius R2 (see FIG. 11) of the inner periphery of the clip 80 in the natural state. Thus, when the clip 80 is expanded and attached to the groove 61a, the clip 80 is brought into a state where both ends thereof are in contact with the bottom of the groove 61a and elastically deformed with both ends as fulcrums as shown in FIG. In the clip 80, positions on both sides in the circumferential direction of the outer peripheral opening 65 a of the receiving portion 65 (A portion in FIG. 10) bulge the most, and a part protrudes radially outward from the outer peripheral surface of the second holder body 61. . For this reason, the outer diameter of the holder 30 as a whole, specifically, the maximum width between the second holder main body 61 and the outer periphery of the clip 80 is larger than the inner diameter of the accommodation hole 3d.

  When the holder 30 is assembled to the accommodation hole 3d 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 comes into contact with and presses the second holder main body 61 (B portion in FIG. 12). As a result, the second holder 60 receives an elastic force from the largest bulging portion of the clip 80 and is urged in the third direction toward the non-gear side away from the worm wheel 1. In this way, the holder 30 is elastically supported with respect to the accommodation hole 3 d by the elastic force of the clip 80.

  Further, the second holder body 61 of the second holder 60 is pressed against the inner peripheral surface of the accommodation hole 3d by receiving the elastic force (biasing force) of the clip 80. 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 of the accommodation hole 3d on the side opposite to the gear, when the reaction force acts from the worm wheel 1 to the worm shaft 2, the first holder 40 biases the spring 70. The second holder 60 also moves to the counter-gear side against the elastic force of the clip 80. Thus, since both the 1st holder 40 and the 2nd holder 60 which support the spring 70 will move, the urging | biasing force which the spring 70 exhibits varies and it becomes unstable.

  On the other hand, since the second holder 60 contacts the inner peripheral surface of the accommodation hole 3d in a stationary state where no reaction force is applied from the worm wheel 1 to the worm shaft 2 as in this embodiment, the worm wheel 1 Even if the reaction force acts, the 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, and thus exhibits a stable urging force against the reaction force of the worm wheel 1. be able to. For this reason, backlash can be reduced more reliably.

  The clip 80 and the groove portion 61a of the second holder 60 have an elastic force (biasing force) that presses the second holder 60 against the inner peripheral surface of the accommodation hole 3d toward the opposite gear side, and the second holder 60 has the accommodation hole 3d. It is set so as to be larger than the frictional force generated when moving toward the inner peripheral surface of the. Specifically, the clip 80 and the groove portion 61 a are configured so that the frictional force generated between the second holder 60 and the first holder 40, the first and second guide portions 62 a and 62 b of the second holder 60, and the second bearing 11. The clip 80 is configured such that the biasing force that biases the second holder 60 is larger than the resultant force of the frictional force generated between the second holder 60 and the friction force. Furthermore, the clip 80 and the groove 61a exert a biasing force against the second holder 60 so that the friction force generated in the second holder 60 against the first holder 40 and the second bearing 11 is overcome. Configured to do. Thereby, the 2nd holder 60 can be more reliably pressed by the clip 80 with respect to the inner peripheral surface of the accommodation hole 3d to the non-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 disposed between the first holder 40 and the second holder 60. And is spaced apart from the second bearing 11 in the axial direction. Thereby, the holder 30 can be made into a compact structure. On the other hand, with such a configuration, the first holder 40 receives the urging 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 receives the urging force of the spring 70 and is not separated from each other. Since the first holder 40, the second holder 60, and the second bearing 11 are integrated by the clip 80 by the clip 80, these can be integrated into the housing hole 3d of the gear case 3 and the assemblability is improved. . Therefore, the holder 30 has a compact configuration, and the ease of assembly into the accommodation hole 3d is improved.

  Furthermore, since the holder 30 is elastically supported by the clip 80 that integrates the holder 30, the holding force of the holder 30 against the accommodation hole 3d can be ensured 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 urging force of the spring 70 can be stabilized.

  As described above, the first holder 40 and the second holder 60 are configured not to overlap each other on the radially outer side of the second bearing 11, and the first holder 40 and the second holder 60 are locked by the clip 80 and the holder By elastically supporting 30, the configuration is made compact without increasing the number of parts, the assembling property of the holder 30 in the accommodation hole 3 d is ensured, the holding force of the holder 30 is ensured, and the urging force of the spring 70 is stabilized. The effects such as can be produced integrally.

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

  However, the present invention is not limited thereto, and the partition wall 61b is not provided in the second holder 60, and the groove 61a may be an annular groove. In this case, it is desirable that the circumferential gap between both ends of the clip 80 is smaller than the width of the outer peripheral opening 65a (the outer diameter of the second bearing 11). According to this, even if it is a case where the clearance gap between the clips 80 and the outer periphery opening part 65a overlap, it is suppressed that the 2nd bearing 11 and the 1st holder 40 drop | omit through this clearance gap. When the gap between the clip 80 and the outer peripheral opening 65a overlap and there is no fear that the second bearing 11 and the first holder 40 will drop off, the groove 61a is formed in an annular shape, and the gap between the clip 80 is the outer peripheral opening 65a. It may be larger than (the outer diameter of the second bearing 11).

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

  In the assembly of the holder 30 and the second bearing 11, as shown in FIG. 13, first, the second bearing 11 is accommodated inside the first holding part 42 a and the second holding part 42 b 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 peripheral 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 and the like) of the first guide 62a and the second guide 62b. Thus, 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 and the spring 70 of the first holder 40 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. Thus, since the urging | biasing direction of the spring 70 and the insertion direction of the 1st holder 40 and the 2nd bearing 11 to the 2nd holder 60 correspond substantially, it can assemble easily.

  Next, the clip 80 is wound around the outer periphery of the second holder 60 while expanding the diameter, and the clip 80 is mounted in the groove 61a. As a result, the first holder 40 and the second holder 60 are prevented from being separated by the clip 80 and are locked via the clip 80. Further, as described above, the curvature radius R2 of the clip 80 is formed smaller than the curvature radius R1 of the groove 61a. Therefore, in a state where 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 into the accommodation hole 3 d of the gear case 3. At this time, a portion of the clip 80 protruding from the groove 61 a is pushed inward in the radial direction, and the second holder 60 is urged 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 urging force of the clip 80.

  After assembling the holder 30 to the gear case 3 in this way, the assembly of the power steering device 100 is completed by inserting the tip of the worm shaft 2 into the hollow portion at the center of the second bearing 11.

  The worm shaft 2 receives an urging force from the spring 70 toward the worm wheel 1 through the first holder 40 and the second bearing 11 when 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 ensured.

  In a state where the worm shaft 2 is inserted into the second bearing 11, the first holder 40 is not in contact with 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 of 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 peripheral surface of the accommodation hole 3d. Thereby, even if the meshing part of the worm shaft 2 and the worm wheel 1 is worn, backlash can be reduced. The first holder 40 is movable toward the worm wheel 1 until it contacts the inner peripheral surface of the accommodation 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 this embodiment will be described. The following modifications are also within the scope of the present invention, and the following modifications and the configurations of the above-described embodiments are combined, or the following modifications and other embodiments described below and combinations thereof are combined, It is also possible to combine the following modifications. Similarly, the modifications described in the description of the above embodiment can be combined with other modifications and other embodiments.

  First, with reference to FIGS. 15 to 17, a modified example of the locking structure of the first holder 40 and the second holder 60 by the clip 80 will be described. 15 and 16, only the clip 80 and the second holder 60 are shown, and the other configurations are not shown.

  In the above embodiment, the clip 80 is formed with a uniform wire diameter, and the groove 61a is formed with a uniform depth. 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. The holder 30 is elastically supported by the clip 80 with respect to the accommodation hole 3d. On the other hand, the holder 30 does not necessarily have to be elastically supported with respect to the accommodation hole 3d.

  Further, when the holder 30 is elastically supported, the second holder 60 is not necessarily pressed against the inner peripheral surface of the accommodation hole 3d by the clip 80. Moreover, even if it is a case where the 2nd holder 60 is pressed on the internal peripheral surface of 3d of accommodation holes, not only the said embodiment but the clip 80 and the groove part 61a can be made into arbitrary structures. In a state before assembling the holder 30 in the accommodation hole 3d, a part of the clip 80 bulges outward in the radial direction, and when the holder 30 is assembled in the accommodation hole 3d, the clip 80 is contracted and the second holder 60 is accommodated in the accommodation hole 3d. What is necessary is just the structure urged | biased toward the inner peripheral surface.

  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. The case where the depth of the bottom portion of the groove portion 61a changes will be described as an example. As shown in FIG. 15, the bottom portion of the groove portion 61a is formed so as to become shallower as it is separated from the partition wall portion 61b in the circumferential direction. In other words, the center of curvature of the bottom 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 main body 61 in the second holder 60. According to this, when the clip 80 is attached to the groove portion 61a, a part of the clip 80 attached to a portion having a shallow depth in the groove portion 61a bulges outward from the groove portion 61a in the radial direction.

  When the clip 80 is attached to the groove 61a and the holder 30 is assembled to the accommodation hole 3d, the outer periphery of the clip 80 comes into contact with the inner peripheral surface of the accommodation hole 3d. For this reason, when the holder 30 is assembled into the accommodation hole 3d, the second holder main body 61 is pressed by the inner periphery of the clip 80 from the shallow gear side to the counter gear side. Thereby, while the holder 30 is elastically supported by the clip 80 as in the above embodiment, the second holder 60 can be pressed against the inner peripheral surface of the accommodation hole 3d. 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. Similarly, when the wire rod diameter of the clip 80 is changed in the circumferential direction, the wire rod diameter of the portion on the gear side may be 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 body 61 in a state where the clip 80 is mounted in the groove 61a. In addition, you may comprise so that both the wire rod diameter of the clip 80 and the depth of the groove part 61a may be changed to the circumferential direction.

  Further, for example, as shown in FIG. 16, a protruding portion 80 a that bulges the clip 80 radially outward may be provided on the inner periphery of the clip 80 or the bottom of the groove portion 61 a. When the raised portion 80a is 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 the protruding part 80a is provided in the groove part 61a, it protrudes in the radial direction outer side from a bottom part, or is protruded and provided inward from the side part of the groove part 61a. By providing the raised portion 80a in the clip 80 or the groove portion 61a, when the clip 80 is attached to the groove portion 61a, the raised portion 80a causes the clip 80 to bulge outward in the radial direction. Thereby, while the holder 30 is elastically supported by the clip 80 as in the above embodiment, the second holder 60 can be pressed against the inner peripheral surface of the accommodation hole 3d. The raised portions 80a are desirably 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 in both the clip 80 and the groove portion 61a.

  Further, the clip 80 and / or the groove 61a may be configured in an oval shape or other shapes instead of a regular arc shape. As another shape, for example, as shown in FIG. 17, the clip 80 is a straight line 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 the pair of arc portions 80b. Connection part 80c. In this case, when the clip 80 is attached to the groove portion 61a, two boundary portions (connection portions) between the pair of arc portions 80b and the connection portion 80c bulge outward in the radial direction. Therefore, the holder 30 is elastically supported with respect to the gear case 3 by the two boundary portions that bulge in the clip 80. Even in this case, the same effect as the above-described embodiment can be obtained.

  As described above, when the holder 30 is elastically supported with respect to the accommodation hole 3d, the configuration is not limited to the configuration in the above embodiment, and other configurations may be used.

  Further, when 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 clip 80 is greatly expanded at two locations on both sides in the circumferential direction of the second opening 43b as in the above embodiment. It is desirable that elastic force acts on the holder 30 from two directions. According to this, the circular second holder 60 can be stably pressed against the inner peripheral surface of the accommodation hole 3d toward the side opposite to the worm wheel 1. 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 places or more.

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

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

  Moreover, in the said embodiment, the 1st support part 51 has the 1st seating surface 51a, the 1st side wall surfaces 51b and 51c, and the 1st surrounding wall surface 51d. The second support part 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 configured by wall surfaces that define the spring accommodating recess 55 that accommodates the spring 70. On the other hand, as long as the 1st support part 51 and the 2nd support part 52 can support so that spring 70 may be urged in the 1st energizing direction and the 2nd energizing direction, it is not restricted to the above-mentioned composition. Any configuration can be adopted. For example, the first support portion 51 and the second support portion 52 may be protrusions that pass through the inside of the spring 70 and support the spring 70 on the inner periphery. In this case, the protrusion may be provided on either the support portion 50 of the first holder 40 or the receiving portion 65 of the second holder 60.

  According to the above 1st Embodiment, there exists an effect shown below.

  In the power steering apparatus 100, the second bearing 11 is guided in 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. As described above, the movement of the second bearing 11 is not guided through the first holder 40, but is directly guided by the first guide portion 62a and the second guide portion 62b. The influence of the dimensional accuracy on the meshing accuracy can be suppressed. Therefore, the meshing accuracy between the worm wheel 1 and the worm shaft 2 can be improved.

  The spring 70 is held by the first holder 40 and the second holder 60. The spring 70 is not aligned with the second bearing 11 in the radial direction and does not bias the second bearing 11 from the outside in the radial direction. The second spring 11 is aligned with the second bearing 11 in the axial direction 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.

  The holder 30 also supports a first support portion 51 that supports the spring 70 so as to exert a biasing force in the first biasing direction and a first support portion 51 that supports the spring 70 so as to exert a biasing force in the second biasing direction. 2 support portions 52. For this reason, regardless of whether the power steering device 100 is mounted on either a left-hand drive vehicle or a right-hand drive vehicle, the spring 70 corresponding to the handle position can exert an urging force in an appropriate direction by the common holder 30. Can do. Therefore, it is not necessary to manufacture the holder 30 for each vehicle type, and the mold for manufacturing the holder 30 is made common, so that the manufacturing cost can be reduced.

  Further, since the holder 30 includes the protrusion 58, when the spring 70 is supported by one of the first support portion 51 and the second support portion 52 that do 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 41b that avoids interference with the worm shaft 2, and the urging direction of the spring 70 can be visually observed through the central hole 41b. Therefore, even in a state where the first holder 40 and the second holder 60 are assembled, it is possible to easily detect erroneous assembly in which the urging 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 a holder opening portion 63 that allows passage of the holding portion 42 of the first holder 40 and the second bearing 11, and the holding portion 42 of the first holder 40 has a holder opening portion. It faces the inner peripheral surface of the accommodation hole 3d through the portion 63. The movement of the first holder 40 is regulated by the first holding part 42a and the second holding part 42b coming into contact with the inner peripheral surface of the accommodation hole 3d through the first opening 43a and the second opening 43b. Therefore, in the holder 30, the first holding part 42 a and the second holding part 42 b of the first holder 40 pass through the first opening part 43 a and the second opening part 43 b of the second holder 60. The guide portions 62b are arranged in the circumferential direction. Thus, since the 1st holder 40 and the 2nd holder 60 do not overlap in the diameter direction of the 2nd bearing 11, the composition of 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 not further affected by the dimensional accuracy of the second holder 60, and is further improved.

  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 dropping from 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 the 1st holder 40 and the 2nd holder 60 are latched by the single clip 80, the retention strength of the holder 30 with respect to the accommodation hole 3d can be ensured, and a number of parts 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 is pressed against the inner peripheral surface of the accommodation hole 3 d. As a result, the urging force that urges the worm shaft 2 toward 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 urged stably.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the said 1st Embodiment, and description is abbreviate | omitted.

  In 2nd Embodiment, the structure which latches the 1st holder 40 and the 2nd holder 60 differs from the said 1st Embodiment. In the first embodiment, the locking member that locks the first holder 40 and the second holder 60 is the C-shaped clip 80, whereas the holder 130 of the second embodiment is attached to the clip 80. Instead, an elastic ring 180 as a locking member is provided. This will be specifically described below. Since 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, description and illustration are omitted as appropriate.

  As shown in FIG. 18, an annular ring groove 161 a is formed on the outer peripheral surface of the second holder main body 161 of the second holder 160. The annular groove 161a has an arc cross section. The annular groove 161a is the deepest deepest portion 161b on the opposite side of the gear in the third direction with respect to the center of the second holder main body 61, and is the shallowest shallowest portion 161c on the gear side. The depth of the annular groove 161a gradually decreases from the deepest portion 161b toward the shallowest portion 161c. The annular groove 161a communicates with the outer peripheral opening 65a of the receiving portion 65 and is separated by the outer peripheral opening 65a. Therefore, the center of curvature O1 at the bottom 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 the state where the elastic ring 180 is mounted in the annular groove 161a, the curvature center O3 of the outer periphery of the elastic ring 180 coincides with the curvature center O1 of the annular groove 161a, and the outer periphery of the second holder body 61 Eccentric to the gear side in the third direction with respect to the curvature center O2 of the surface.

  Similar to the first embodiment, the first holder 40 is attached to the second holder 160 through the outer peripheral opening 65a by attaching the elastic ring 180 to the annular groove 161a with the first holder 40 assembled to the second holder 160. Exit from 160 is restricted. In this way, 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 161a, a part of the elastic ring 180 protrudes radially outward from the outer peripheral surface of the second holder main body 161. In the deepest portion 161b of the annular groove 161a, the elastic ring 180 does not protrude from the outer peripheral surface of the second holder main body 161. On the contrary, the elastic ring 180 protrudes the largest at the shallowest portion 161c.

  When the holder 30 is assembled into the accommodation hole 3d of the gear case 3, a part of the elastic ring 180 protruding radially outward from the annular groove 161a is pushed radially inward and compressed. Therefore, the elastic force of the elastic ring 180 to be compressed acts on the second holder 160. The elastic ring 180 is compressed most at the shallowest portion 161c, and the amount of compression becomes smaller toward the deepest portion 161b. For this reason, the second holder 160 is urged toward the counter gear side in the third direction so as to be separated from the worm wheel 1 by the compressed elastic ring 180. Thereby, the holder 130 is elastically supported with respect to the accommodation hole 3d by the elastic force of the elastic ring 180 similarly to the latching structure by the clip 80 in the said 1st Embodiment.

  Further, the second holder main body 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 of 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 elastic ring 180 is formed so that the wire diameter is uniform and the depth of the annular groove 161a changes 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 curvature center O3 of the outer peripheral surface of the elastic ring 180 attached to the annular groove 161a is eccentric with respect to the curvature center O2 of the outer peripheral surface of the second holder main body 161, as in the above embodiment. In this case, in order for the second holder 160 to be pressed against the inner peripheral surface of the accommodation hole 3d toward the counter gear side in the third direction, a portion of the elastic ring 180 having a large wire diameter is positioned on the gear side. It is necessary to attach to. For this reason, although an assembly process becomes complicated, there can exist an effect similar to the said embodiment. Moreover, you may comprise so that both the depth of the annular groove 161a and the wire diameter of the elastic ring 180 may change to the circumferential direction.

  Further, since it is the same as that of the first embodiment, illustration and detailed description are omitted, but a raised portion 80a is provided in the elastic ring 180 and / or the annular groove 161a, and the holder 130 is elastically supported by the elastic ring 180. In addition, the second holder 160 may be configured to be pressed against the inner peripheral surface of the accommodation hole 3d. In addition, the elastic ring 180 may be formed in an elliptical shape other than a circular shape or other shapes.

  According to the above 2nd Embodiment, there exists an effect similar to the said 1st Embodiment.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the said 1st Embodiment, and description is abbreviate | omitted.

  In the third embodiment, the holder 230 moves the second bearing 11 toward the worm wheel 1 and the first holder 240 having the holding portion 242 that holds the second bearing 11, as shown in FIGS. 20 and 21. A second holder 260 having a guiding portion 62 for guiding, and a compressed state provided between the first holder 240 and the second holder 260, the second bearing 11 is attached to the worm wheel 1 via the first holder 240. And a spring 70 to be biased.

  As shown in FIGS. 22 and 23, the first holder 240 includes a plate-like first holder main body 241, a holding part 242 provided in the first holder main body 241, and an outer periphery of the outer ring 11 a of the second bearing 11. It has the opening part 243 which exposes a part of surface, and the seating part 245 to which one end of the spring 70 sits. A central hole 41b is formed in the first holder body 241 as in the first embodiment.

  As shown in FIGS. 20 and 22, the holding portion 242 is a single wall portion provided on the opposite gear side in the third direction than the second bearing 11. The holding part 242 protrudes from the first holder main body part 241 along the central axis of the second bearing 11. The holding portion 242 is formed in an arc shape such that the radially inner side 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.

  The opening 243 is provided in the circumferential direction of the holding part 242. In the first holder 240, the holding portion 242 is formed in the range of about 120 °, and the remaining 240 ° range is formed as the opening 243. The opening 243 is formed by cutting out a part of the cylindrical wall portion 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 third embodiment, the first holder 43a is not provided in the first holder 40 of the first embodiment, and the first opening 43a and the second opening 43b are connected by the opening. It is formed in a different shape. The opening 243 in the third embodiment also exposes a part of the outer peripheral surface of the outer ring 11 a of the second bearing 11 held by the holding unit 242 to the outside.

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

  In the present embodiment, the spring 70 is supported by a 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 that exerts a biasing force in the first biasing direction is seated. As shown in FIG. 23, the seating portion 245 may be provided with only the seating portion 245 corresponding to the direction in which the spring 70 is supported. In addition, like the first receiving surface 67 and the second receiving surface 68 of the first embodiment, the seating portion 245 exhibits the urging force of the spring 70 in either the first urging direction or the second urging direction. Even in this case, it may be configured such that one end of the spring 70 is 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 in the second holder main body portion 261, and the guide portion 62. The auxiliary holding part 262 that holds the second bearing 11 together with the holding part 42 of the holder 40, the spacer part 266 on which the intermediate part 70 c between both end parts 70 a and 70 b of the spring 70 is seated, and the positioning hole 3 e of the gear case 3. And a positioning convex portion 64 to be inserted.

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

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

  A spring 70 is accommodated in the notch 267. As shown in FIGS. 25 and 26, the notch 267 is defined 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 a biasing force in either the first biasing direction or 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 1st guide part 62a and the 2nd guide part 62b have a pair of guide surfaces 62c and 62d provided in parallel with each other, and claw parts 62e and 62f, respectively. Also in this embodiment, a part of the outer ring 11a of the second bearing 11 exposed through the opening 243 of the first holder 240 is in direct contact with the first guide part 62a and the second guide part 62b.

  The auxiliary holding portion 262 is an arcuate 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 part 262 connects the first guide part 62a and the second guide part 62b in the circumferential direction.

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

  The spacer portion 266 is provided in the notch 267 so as to connect the first wall surface 267a and the second wall surface 267b constituting the notch 267. The intermediate portion 70 c of the spring 70 received in the notch 267 is seated on the spacer portion 266. The spacer portion 266 includes a first spacer portion 266a that is perpendicular to the first biasing direction and a second spacer portion 266b that is perpendicular to the second biasing direction. Depending on whether the spring 70 is seated on the first spacer portion 266a or the second spacer portion 266b, the urging direction of the spring 70 can be changed. Thus, in the third embodiment, the spacer portion 266 (the first spacer portion 266a and the second spacer portion 266b) applies a biasing force to the spring 70 in the first biasing direction and the second biasing direction. It corresponds to a support part (first support part, second support part) that is supported so as to exhibit.

  As shown in FIG. 26, one end portion 70a of the spring 70 is seated on the seat portion 245 of the first holder 240, and the other end portion 70b is seated on the inner peripheral surface of the accommodation hole 3d. Between the one end part 70a and the intermediate part 70c of the spring 70, and between the other end part 70b and the intermediate part 70c are each 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 portion 70a does not act on the other end portion 70b, and vice versa. Therefore, in the spring 70, one spring action is exhibited between the one end part 70a and the intermediate part 70c, and one spring action is exhibited between the intermediate part 70c and the other end part 70b, so that two independent The spring action is apparently exhibited.

  In the present embodiment, the spring 70 between the one end portion 70a and the intermediate portion 70c exerts 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. For this reason, the holding part 242 and the auxiliary holding part 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 integrated, without separating. That is, a part between the one end portion 70 a and the intermediate portion 70 c of the spring 70 functions as a locking member that locks the first holder 240 and the second holder 260.

  Further, the spring 70 between the one end portion 70 a and the intermediate portion 70 c exerts a biasing force that biases the first holder 240 toward the gear side with respect to the second holder 260. Therefore, the spring 70 also functions as a biasing member.

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

  Thus, in this embodiment, the urging 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 intermediate portion 70c has an urging force in the direction toward the non-gear side (hereinafter referred to as “first urging force F1”). 2 Demonstrate against the holder 260. The spring 70 between the other end portion 70 b and the intermediate portion 70 c exerts an urging force in the direction toward the gear side (hereinafter referred to as “second urging force F <b> 2”) on the second holder 260. When the first urging force F1 is larger than the second urging force F2, the second holder 260 is urged to move toward the non-gear side, so that the worm shaft 2 is reliably directed toward the gear side. Cannot be energized. Therefore, the holder 230 is configured such that the second urging force F2 is larger than the first urging force F1 in order to urge the worm shaft 2 and the second bearing 11 toward the gear side. Specifically, the position of the intermediate portion 70c seated on the spacer portion 266 in the spring 70 (in other words, the compression amount between the one end portion 70a and the intermediate portion 70c and between the other end portion 70b and the 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 urging force F2 is configured to be larger than the first urging force F1. Accordingly, the second holder 260 is prevented from moving toward the non-gear side, and the worm shaft 2 and the second bearing 11 can be biased more reliably toward the gear side.

  In assembling the holder 230, first, the first holder 240 and the second holder 260 are combined so that the seating portion 245 of the first holder 240 passes through the passage hole 261 a of the second holder 260. Further, 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 spacer portion 266a, and the one end portion 70a is compressed by a predetermined amount and seated on the seat portion 245. In this way, 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 in the accommodation hole 3d, the holder 230 is accommodated in the accommodation hole 3d while the other end portion 70b of the spring 70 is pressed and contracted so that the positioning projection 64 is inserted into the positioning hole 3e. Thereby, the holder 230 is elastically supported with respect to the accommodation hole 3d by the urging force between the intermediate part 70c and the other end part 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 between the worm wheel 1 and the worm shaft 2 is the dimensional accuracy of the first holder 40. Not affected.

  The spring 70 has both functions of a biasing member that biases the second bearing 11 via the first holder 40 and a locking member that locks the first holder 40 and the second holder 60. Since it demonstrates, the number of parts can be reduced.

  Since the other end of the spring 70 is seated on the inner peripheral surface of the accommodation hole 3d, the function of pressing the second holder 60 against the inner peripheral surface of the accommodation hole 3d is not exhibited, but the rest is the same as in the first embodiment. The same effect is produced.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  The power steering apparatus 100 includes a worm shaft 2 that rotates as the electric motor 7 is driven, a worm wheel 1 that meshes with the worm shaft 2, a second bearing 11 that rotatably supports the tip side of the worm shaft 2, a worm A gear case 3 that accommodates the shaft 2 and holders 30, 130, and 230 that are disposed in the gear case 3 and accommodate the second bearing 11, and the holders 30, 130, and 230 hold the second bearing 11. 1 holder 40,240, 2nd holder 60,160,260 which has the guide part 62 which guides the movement of the 2nd bearing 11 toward the worm wheel 1, 1st holder 40,240 and 2nd holder 60,160, 260, a spring 70 provided in a compressed state, and the first holder 40, 240 and the second holder 60, 160, 60, a support portion (support portion 50, spacer portion 266) that supports the spring 70, and the support portion (support portion 50, spacer portion 266) is biased in the first biasing direction. The first support portion (the first support portion 51 and the first spacer portion 266a) that can support the spring 70 so as to exert the urging force, and exerts a biasing force in a second biasing direction different from the first biasing direction. A second support portion (second support portion 52, second spacer portion 266b) that can support the spring 70, and the spring 70 is a first support portion (first support portion 51, between the first The seat portion 266a) and the second support portion (the second support portion 52 and the second spacer portion 266b) are supported.

  In this configuration, the urging member is provided between the first holder 40, 240 and the second holder 60, 160, 260, and the support portion (support portion 50, spacer portion 266) is the first holder 40, 240 and It is provided in one of the second holders 60, 160, 260. Further, depending on which of the first support part (first support part 51, first spacer part 266a) and the second support part (second support part 52, second spacer part 266b) supports the spring 70, The urging direction by the spring 70 can be changed. As described above, since the biasing direction of the spring 70 can be changed depending on the configuration of the holders 30, 130, and 230, the common holders 30, 130, and 230 are used for the left-hand drive vehicle and the right-hand drive vehicle, respectively. In addition, it is not necessary to process the gear case 3 in order to make the device configuration common. Therefore, the manufacturing cost of the 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 a spring accommodation recess 55 provided in the support portion 50, and the spring accommodation recess 55 is partitioned by the first support portion 51. The first housing recess 56 and the second housing recess 52 defined by the second support 52 are provided so that the first housing recess 56 and the second housing recess 56 intersect each other. .

  In the power steering device 100, one of the first holder 40 and the second holder 60 supports one of the first support part 51 and the second support part 52 that do not support the biasing member. In such a case, a misassembly prevention unit that obstructs the assembly of the first holder 40 and the second holder 60 is formed.

  With this configuration, when the holder 30 is assembled, an error in the assembly direction of the urging member can be easily detected.

  In the power steering apparatus 100, the first holder 40, 240 is formed with a central hole 41b that avoids interference with the worm shaft 2, and the biasing member faces the central hole 41b and the first support portion (first support). Part 51, first spacer part 266a) or second support part (second support part 52, second spacer part 266b).

  In this configuration, even after the holders 30, 130, and 230 are assembled, an error in the assembly direction of the spring 70 can be easily detected by confirming the biasing direction of the spring 70 by visual inspection from the central hole 41b. can do.

  Further, the present specification includes the following inventions.

  The power steering apparatus 100 includes a worm shaft 2 that rotates as the electric motor 7 is driven, a worm wheel 1 that meshes with the worm shaft 2, a second bearing 11 that rotatably supports the tip side of the worm shaft 2, a worm A gear case 3 that accommodates the shaft 2 and holders 30, 130, and 230 that are accommodated in an accommodation hole 3d provided in the gear case 3 and accommodate the second bearing 11, and the holders 30, 130, and 230 are the second bearings. Of the second bearing 11 through the openings 43 and 243 and the first holders 40 and 240 having the holding portions 42 and 242 that hold the outer periphery of the first bearing 11 and the openings 43 and 243 that expose a part of the outer periphery of the second bearing 11. Second holders 60 and 160 having a guide portion 62 that guides the movement of the second bearing 11 toward the worm wheel 1 with the outer periphery contacting. It 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 for movement. Thus, since the movement of the second bearing 11 is not guided through the first holders 40 and 240 but directly guided by the guide portion 62, the dimensional accuracy of the first holders 40 and 240 is improved. The influence on the meshing accuracy is suppressed. Accordingly, the meshing accuracy between the worm shaft 2 and the worm wheel 1 in the power steering device 100 can be improved.

  The power steering apparatus 100 includes a holder opening 63 that allows the second bearing 11 and the holding portion 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, since the assembly direction of the 1st holder 40 and the 2nd bearing 11 to the 2nd holder 60 and the urging | biasing direction (movement direction of the 2nd bearing 11) by an urging member correspond, an assembly property improves. To do.

  In the power steering apparatus 100, the holding portions 42 and 242 of the first holders 40 and 240 face the inner peripheral surface of the accommodation hole 3 d through the holder openings 63 and 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 and are not restricted in movement, but directly face the inner peripheral surface of the accommodation hole 3d. For this reason, the dimensional accuracy of the second holders 60 and 260 in the moving direction of the second bearing 11 is suppressed 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 portion 62 of the second holder 60 has first guide surfaces 62 c and 62 d that are in contact with the outer peripheral surface of the second bearing 11 and are provided in parallel with each other across the central axis of the second bearing 11. The holder opening 63 of the second holder 60 is composed of a first guide 62a and a second guide 62b, and the first holder opening 63a is provided between the first guide 62a and the second guide 62b in the circumferential direction. And the holding part 42 of the first holder 40 is composed of a first holding part 42a and a second holding part 42b provided to face each other across the central axis of the second bearing 11, The first holding part 42a and the second holding part 42b are circumferentially connected to the first guide part 62a and the second guide part 62b through the first opening part 43a and the second opening part 43b, respectively. Side by side to be provided.

  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 3d. Can be configured compactly.

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

  In the power steering apparatus 100, the first holder 40 has a support portion 50 that is provided alongside the holding portion 42 in the axial direction of the second bearing 11 and supports the spring 70, and the second holder 60 is the second bearing 11. A receiving portion 65 is provided alongside the guide portion 62 in the axial direction to support the biasing member, and the spring 70 is interposed between the supporting portion 50 of the first holder 40 and the receiving portion 65 of the second holder 60. Held in a compressed state.

  In these configurations, the spring 70 is provided so as to be aligned in the axial direction with respect to the second bearing 11 and biases the second bearing 11 in the radial direction. For this reason, the configuration of the power steering device 100 can be made compact in the radial direction of the second bearing 11.

  The power steering apparatus 100 includes a worm shaft 2 that rotates as the electric motor 7 is driven, a worm wheel 1 that meshes with the worm shaft 2, a second bearing 11 that rotatably supports the tip side of the worm shaft 2, a worm A gear case 3 provided with an accommodation hole 3d for accommodating the shaft 2, and holders 30, 130, 230 accommodated in the accommodation hole 3d provided in the gear case 3 for accommodating the second bearing 11, and the holders 30, 130, 230, first holders 40, 240 for holding the second bearing 11, second holders 60, 160, 260 having a guide portion 62 for guiding the movement of the second bearing 11 toward the worm wheel 1, and the first holder 40, 240 and the second holders 60, 160, 260 are provided in a compressed state. And the second holder 60 allows the guide 62 to pass through the second bearing 11 and the first holders 40 and 240 in the direction in which the second bearing 11 is guided. The holder holders 63 and 263 are allowed, and the first holders 40 and 240 face the inner peripheral surface of the accommodation hole 3d through the holder openings 63 and 263.

  In this configuration, the first holders 40 and 140 face the inner peripheral surface of the accommodation hole 3d through the holder openings 63 and 263 of the second holders 60, 160, and 260. Thus, since the first holder 40, 140 and the second holder 60, 160, 260 are configured without overlapping in the direction in which the guide portion 62 guides, the holder 30, 130, 230 is configured to be compact. Can do. Therefore, the power steering apparatus 100 can be reduced in size.

  In the power steering apparatus 100, the holders 30, 130, and 230 further include a locking member (a clip 80, an elastic ring 180, a spring 70) that locks the first holder 40 and the second holder 60. The (clip 80, elastic ring 180, spring 70) elastically supports the holders 30, 130, and 230 with respect to the accommodation hole 3d.

  In this configuration, the retaining member (the clip 80, the elastic ring 180, and the spring 70) secures the holding force of the holder 30 with respect to the accommodation hole 3d, so that the number of parts can be reduced.

  In the power steering device 100, the second holders 60 and 160 are urged in a direction away from the worm wheel 1 by the locking members (clip 80, elastic ring 180) and pressed against the inner peripheral surface of the accommodation hole 3d.

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

  In the power steering device 100, the second holder 60 has a groove portion 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 portion 61a.

  In the power steering apparatus 100, the clip 80 has a wire diameter that changes in the circumferential direction.

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

  In the power steering apparatus 100, at least one of the groove 61a and the clip 80 is provided with a raised portion 80a that causes the clip 80 to bulge outward in the radial direction.

  In the power steering apparatus 100, the clip 80 includes a pair of arc portions 80b formed in an arc shape and a linear connection portion 80c that connects 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 apparatus 100 according to the second embodiment, the depth of the annular groove 161a changes in the circumferential direction.

  In the power steering device 100 according to the third embodiment, the urging member and the locking member are configured as an integrally formed spring 70, and the spring 70 has one end 70 a seated on the first holder 240 and the other. The end portion 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 portion 70a of the spring 70 is seated. The second holder 260 includes an auxiliary holding portion 262 that holds the second bearing 11 together with the holding portion 242, and a spacer portion 266 on which an intermediate portion 70c between the one end portion 70a and the other end portion 70b of the spring 70 is seated. 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 intermediate portion 70c of the spring 70, and the first holder 24 is pressed. And the second holder 260 are locked to each other.

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

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above 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 that is provided separately from the steering shaft and meshes with the rack shaft.

  DESCRIPTION OF SYMBOLS 1 ... Worm wheel, 2 ... Worm shaft, 3 ... Gear case, 3d ... Accommodating hole, 7 ... Electric motor, 11 ... 2nd bearing (bearing), 30, 130, 230 ... Holder, 40, 240 ... 1st holder, 41b ... center hole, 42 ... holding part, 42a ... first holding part, 42b ... second holding part, 43 ... opening, 43a ... first opening, 43b ... second opening, 50 ... support part, 51 ... first DESCRIPTION OF SYMBOLS 1 support part, 52 ... 2nd support part, 55 ... Spring accommodation recessed part, 56 ... 1st accommodation recessed part, 57 ... 2nd accommodation recessed part, 58 ... Protrusion (misassembly prevention part), 60, 160, 260 ... 2nd holder , 61a ... groove portion, 62 ... guide portion, 62a ... first guide portion, 62b ... second guide portion, 63, 263 ... holder opening, 63a ... first holder opening, 63b ... second holder opening, 65 ... Receiving part, 70 ... spring (biasing member, Stop member), 70a ... one end, 70b ... other end, 70c ... intermediate part, 80 ... clip (locking member), 80a ... raised part, 80b ... arc part, 80c ... connecting part, 100 ... power steering device, 161a ... annular groove, 180 ... elastic ring (locking member), 262 ... auxiliary holding part, 266 ... spacer part (support part), 266a ... first spacer part (first support part), 266b ... second space Seat (second support part)

Claims (4)

A power steering device,
A worm shaft that rotates as the electric motor is driven;
A worm wheel meshing with the worm shaft;
A bearing that rotatably supports the tip side of the worm shaft;
A gear case that houses the worm shaft;
A holder disposed in the gear case and containing the bearing,
The holder is
A first holder for holding the bearing;
A second holder having a guide portion for guiding the movement of the bearing toward the worm wheel;
An urging member provided in a compressed state between the first holder and the second holder;
A support portion that is provided in any one of the first holder and the second holder and supports the biasing member;
The support part 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 so as to exert a biasing force in a second biasing direction different from the first biasing direction;
The power steering apparatus, wherein the urging member is supported by one of the first support part and the second support part. The support portion is provided on the first holder,
The urging member is housed in a spring housing recess provided in the support portion,
The spring accommodating recess has a first accommodating recess defined by the first support and a second accommodating recess defined by the second support,
2. The power steering apparatus according to claim 1, wherein the first housing recess and the second housing recess are provided so as to intersect each other.   In one of the first holder and the second holder, when one of the first support part and the second support part that does not support the biasing member supports the biasing member, The power steering apparatus according to claim 1 or 2, wherein a misassembly prevention unit that inhibits assembly of the first holder and the second holder is formed. A central hole is formed in the first holder to avoid interference with the worm shaft,
4. The power steering apparatus according to claim 1, wherein the biasing member is supported by the first support portion or the second support portion facing the central hole. 5.

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