JP2010038254A - Mounting structure for retaining ring and steering device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure for a retaining ring capable of inhibiting play of a target. <P>SOLUTION: In the mounting structure 68 for the retaining ring, the retaining ring 50 positioning a first bearing 31 as the target is fitted in an inner peripheral groove 47 formed on an inner periphery of a first holding hole 41. A body 70 of the retaining ring 50 is provided with first and second end surfaces 72 and 73. The first end surface 72 abuts on the target. A protrusion 71 is formed on the second end surface 73. The inner peripheral groove 47 includes a first inner wall surface 81 confronting the first end surface 72, a second inner wall surface 82 confronting the second end surface 73, and an annular groove 83 in which the protrusion 71 is arranged. A pair of cone tapered cam surfaces 75 and 84 running along each other is formed on the second end surface 73 of the body 70 and the second inner wall surface 82 of the inner peripheral groove 47. The protrusion 71 is fitted to a third inner wall surface 85 on a radial inner side of the annular groove 83, and thereby, contraction of the retaining ring 50 exceeding a prescribed amount L3 is regulated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a retaining ring mounting structure and a vehicle steering apparatus.

The vehicle steering apparatus has a rack shaft and a pinion shaft that constitute a steering mechanism. The pinion shaft is rotatably supported by a cylindrical housing via a bearing. In addition, a retaining ring is used to easily position the bearing in the axial direction within the housing. The retaining ring is fitted in an inner peripheral groove formed on the inner periphery of the housing.
Moreover, there exists patent document 1 as a technique for preventing the rattling of the target object attached with a retaining ring, for example. The retaining ring of Patent Document 1 has a plate shape as a whole.
Japanese Utility Model Publication No. 6-10610

  By the way, in the above-described vehicle steering apparatus, road surface input (also referred to as reverse input) acting on the wheels is transmitted to the pinion shaft via the rack shaft of the steering mechanism. Due to the reverse input described above, the pinion shaft may be pushed up in the axial direction. At the same time, the retaining ring is pushed up in the axial direction via the bearing. As a result, the pinion shaft, the bearing, and the retaining ring may be rattled in the axial direction. Furthermore, due to such rattling, the rack shaft and the pinion shaft are not properly engaged with each other.

In addition, a retaining ring is used in devices other than the vehicle steering device, and there is a demand for suppressing rattling of the object as in the above-described vehicle steering device.
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a retaining ring mounting structure and a vehicle steering device that can suppress rattling of an object.

  The retaining ring mounting structure (68) of the present invention has a retaining ring (50, 50A, 50B, 50B) for positioning the object (31) in the axial direction (A2) of the retaining hole (41) for retaining the object. 50C) is fitted in an inner circumferential groove (47) formed in the inner circumference (44) of the holding hole, in which the retaining ring has first and second end faces ( 72, 72C, 73, 73B), the first end surface (72, 72C) abuts on the object, and the second end surface (73, 73B) projects. (71, 71A, 71B) are formed, and the inner circumferential groove includes a first inner wall surface (81) facing the first end surface and a second inner wall surface (82 facing the second end surface). 82B), and the protrusion formed on the second end surface of the main body is Arranged in the annular groove (83, 83B) formed in the second inner wall surface of the inner circumferential groove, the second end surface (73) of the main body and the second inner wall surface of the inner circumferential groove (82) is formed with a pair of conical taper-shaped cam surfaces (75, 84) extending along each other, or on the protrusion (71B) and the bottom (89) of the annular groove (83B). A pair of conical taper-shaped cam surfaces (75, 84) are formed, and the pair of conical taper-shaped cam surfaces provide a force for elastically expanding the retaining ring and the retaining ring as the object. The annular groove functions as a third inner wall surface (85) having a relatively small diameter (L1) and a fourth inner wall having a relatively large diameter (L2). And the protrusion engages with the third inner wall surface of the annular groove. Accordingly, it exceeds a predetermined amount of the stop ring (L3) contraction is restricted, it is characterized by (claim 1).

  According to the present invention, the force that expands the retaining ring by elastic restoration is converted into a force that presses the retaining ring against the object along the axial direction of the holding hole by the action of the pair of cam surfaces. Shaking of the object in the axial direction can be suppressed. Further, when an external force that pushes the object in the axial direction (for example, road surface input) acts on the retaining ring and contracts the retaining ring by a predetermined amount, the protrusion engages with the third inner wall surface of the annular groove. Thereby, since the shrinkage | contraction of the quantity exceeding the predetermined amount of a retaining ring is controlled, the shakiness of the target object regarding the said axial direction can be suppressed reliably.

In the present invention, a gap (88) may be formed between the protrusion and the fourth inner wall surface of the annular groove (claim 2). In this case, since the retaining ring can be sufficiently expanded in the inner circumferential groove, rattling of the object is reliably suppressed.
In the present invention, the retaining ring has a pair of end portions (76) that are separated from each other in the circumferential direction (C3) of the retaining ring, and the protrusion is disposed at least at the pair of end portions. (Claim 3). In this case, when the protrusions arranged at the pair of end portions engage with the third inner wall surface of the annular groove, the contraction of the retaining ring is effectively restricted so that the entire shape of the retaining ring is destroyed. Therefore, it is possible to further suppress the rattling of the object in the axial direction.

  The vehicle steering device (1) of the present invention includes a steering mechanism (11) that converts the rotation of the pinion shaft (7) into an axial movement of the rack shaft (10), and a holding hole (41 of the housing (13)). And the bearing (31) as the object for rotatably supporting the pinion shaft, and the axial movement of the bearing using the retaining ring mounting structure (68) of the present invention (Claim 4).

  According to the vehicle steering apparatus of the present invention, for example, when a reverse input as an external force is applied to a bearing from a wheel via a rack shaft and a pinion shaft, movement of the retaining ring in the axial direction is restricted. Thereby, since the shakiness of the bearing and the pinion shaft in the axial direction is suppressed, it is possible to suppress the generation of noise due to the axial movement of the pinion shaft. In addition, since the effect of suppressing the generation of this abnormal noise can be achieved with a simple structure in which the retaining ring protrusion and the annular groove are engaged, the vehicle steering device can be made inexpensive.

  In addition, although the alphanumeric characters in the parentheses indicate reference signs of corresponding components in the embodiments described later, the scope of the claims is not limited by these reference signs.

  A preferred embodiment of the present invention will be described with reference to the accompanying drawings. In this embodiment, the retaining ring mounting structure will be described in the case where it is applied to an electric power steering device as a vehicle steering device. The retaining ring mounting structure of the present invention can be applied to, for example, a manually steered steering device as a vehicle steering device, or can be applied to a mechanical device other than a vehicle steering device.

  FIG. 1 is a schematic diagram of a schematic configuration of an electric power steering apparatus to which a retaining ring mounting structure according to a first embodiment of the present invention is applied. Referring to FIG. 1, an electric power steering system (EPS) 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, and a first universal joint 4 attached to the steering shaft 3. An intermediate shaft 5 connected to the intermediate shaft 5, a pinion shaft 7 connected to the intermediate shaft 5 via a second universal joint 6, and rack teeth 9 that mesh with pinion teeth 8 provided near the end of the pinion shaft 7. And a rack shaft 10 as a steered shaft extending in the left-right direction of the vehicle.

  The pinion shaft 7 and the rack shaft 10 constitute a steering mechanism 11 composed of a rack and pinion mechanism. The rack shaft 10 is supported in a housing 13 fixed to the vehicle body 12 so as to be linearly reciprocable via a plurality of bearings (not shown). A pair of tie rods 14 are coupled to the rack shaft 10. Each tie rod 14 is connected to a corresponding steered wheel 16 via a corresponding knuckle arm 15.

When the steering member 2 is operated to rotate the steering shaft 3, this rotation is caused by the pinion teeth 8 and the rack teeth 9 to linearly move the rack shaft 10 along the left-right direction of the automobile (the axial movement of the rack shaft 10). Equivalent to.). Thereby, the turning of the steered wheels 16 is achieved.
The steering shaft 3 is divided into an input shaft 17 connected to the steering member 2 and an output shaft 18 connected to the pinion shaft 7. The input shaft 17 and the output shaft 18 are connected to each other on the same axis via a torsion bar 19. When steering torque is input to the input shaft 17, the torsion bar 19 is elastically torsionally deformed, whereby the input shaft 17 and the output shaft 18 are rotated relative to each other.

  A torque sensor 20 that detects a steering torque based on the amount of relative rotational displacement between the input shaft 17 and the output shaft 18 via the torsion bar 19 is provided. A vehicle speed sensor 21 for detecting the vehicle speed is also provided. An ECU (Electronic Control Unit) 22 is provided as a control device. An electric motor 23 for generating a steering assist force and a speed reducer 24 for reducing the output rotation of the electric motor 23 are provided.

  Detection signals from the torque sensor 20 and the vehicle speed sensor 21 are input to the ECU 22. The ECU 22 controls the steering assisting electric motor 23 based on the torque detection result, the vehicle speed detection result, and the like. The output rotation of the electric motor 23 is decelerated via the speed reducer 24, transmitted to the pinion shaft 7, and converted into a linear motion of the rack shaft 10, thereby assisting in steering.

  FIG. 2 is a cross-sectional view of a main part of the electric power steering apparatus 1 of FIG. Referring to FIG. 2, the pinion shaft 7 has a tooth portion 26 and first and second shaft portions 27 and 28. The tooth part 26 consists of a helical gear. The outer periphery of the tooth portion 26 has a plurality of pinion teeth 8. The first and second shaft portions 27 and 28 are arranged on both sides of the tooth portion 26 with respect to the axial direction A1 of the pinion shaft 7.

The rack shaft 10 extends in a direction perpendicular to the paper surface of FIG. 2 and is formed of a helical rack and meshes with a tooth portion 26 formed of a helical gear.
The electric power steering apparatus 1 includes a first bearing 31 that rotatably supports the first shaft portion 27 of the pinion shaft 7 and a second shaft portion 28 that rotatably supports the second shaft portion 28 of the pinion shaft 7. The bearing 32, the rack shaft support device 33 that supports the rack shaft 10, and the housing 13 described above are included. The housing 13 accommodates a part of the pinion shaft 7, a part of the rack shaft 10, a first bearing 31, a second bearing 32, and a rack shaft support device 33.

The rack shaft support device 33 includes a cylindrical support yoke 35 as a support member that supports the rack shaft 10, a sealing member 36 that seals the opening of the housing 13, and the pinion of the rack shaft 10 via the support yoke 35. And an urging member 37 that urges the shaft 7 toward the shaft 7.
The housing 13 includes a pinion housing 39 having a cylindrical shape extending along the axial direction A1 of the pinion shaft 7. A part of the pinion shaft 7 and the first and second bearings 31 and 32 are accommodated in the pinion housing 39.

An annular seal member 40 is attached to the inner periphery of one end of the pinion housing 39 in the axial direction A1 of the pinion shaft 7. The seal member 40 prevents entry of moisture and the like. The other end of the pinion housing 39 in the axial direction A1 of the pinion shaft 7 is closed.
The pinion housing 39 has a first holding hole 41 for holding the first bearing 31 and a second holding hole 42 for holding the second bearing 32. The first and second holding holes 41 and 42 are spaced apart from each other with respect to the axial direction A1 of the pinion shaft 7. The tooth portion 26 is disposed between the first and second holding holes 41 and 42. A second holding hole 42 is disposed in the vicinity of the other end of the pinion housing 39 in the axial direction A1 of the pinion shaft 7. In addition, a first holding hole 41 is disposed in an intermediate portion of the pinion housing 39 with respect to the axial direction A1 of the pinion shaft 7.

  FIG. 3 is an enlarged view of a main part of FIG. Referring to FIG. 3, the first holding hole 41 includes a first large diameter portion 44 as an inner periphery, a small diameter portion 45 as an inner periphery, and the first large diameter portion 44 and the small diameter portion 45. An end wall 46 to be connected, an inner peripheral groove 47 adjacent to the first large diameter portion 44, and a second large inner periphery adjacent to the inner peripheral groove 47 on the side opposite to the first large diameter portion 44. And a diameter portion 48.

The end wall 46 is disposed adjacent to the first large diameter portion 44. The end wall 46 and the inner circumferential groove 47 are opposite to each other with respect to the axial direction A2 of the first holding hole 41 (corresponding to the axial direction A1 of the pinion shaft 7) with the first large diameter portion 44 interposed therebetween. Has been placed.
In addition, the electric power steering apparatus 1 of the present embodiment has a retaining ring 50 that restricts the movement of the first bearing 31 in the axial direction A2 of the first holding hole 41. The retaining ring 50 is fitted in the inner circumferential groove 47.

The first bearing 31 is fitted in the first large diameter portion 44. The first bearing 31 is positioned on both sides of the first holding hole 41 in the axial direction A <b> 2 by the end wall 46 and the retaining ring 50.
The 1st bearing 31 consists of a ball bearing as a rolling bearing, for example. The first bearing 31 includes an outer ring 52, an inner ring 53, a rolling element 54 composed of a plurality of balls interposed between the outer ring 52 and the inner ring 53, and a cage 55 that holds the rolling element 54. .

  The inner ring 53 of the first bearing 31 can move along with the pinion shaft 7 in the axial direction A1 of the pinion shaft 7. For example, the inner ring 53 of the first bearing 31 is fitted into the outer periphery 57 of the first shaft portion 27 of the pinion shaft 7 in a press-fit state. The inner ring 53 of the first bearing 31 is in contact with the stepped portion 58 of the pinion shaft 7. At the same time, the inner ring 53 is in contact with a retaining ring 60 fitted in the outer peripheral groove 59 of the first shaft portion 27. Thereby, the movement of the inner ring 53 in the axial direction A1 of the pinion shaft 7 is restricted.

The outer ring 52 is held in the first holding hole 41 of the pinion housing 39 of the housing 13. Specifically, the outer ring 52 of the first bearing 31 is fitted in the first large-diameter portion 44 as the inner periphery of the first holding hole 41 of the pinion housing 39 in a clearance fit state.
One end surface 62 of the outer ring 52 is in contact with the end wall 46 of the first holding hole 41 of the pinion housing 39. Thereby, the movement of the outer ring 52 in one direction of the axial direction A2 of the first holding hole 41 is restricted.

The other end surface 63 of the outer ring 52 is in contact with the retaining ring 50. The retaining ring 50 is engaged with the inner peripheral groove 47 of the first holding hole 41 of the pinion housing 39. Thereby, the movement of the outer ring | wheel 52 to the other direction of the axial direction A2 of the 1st holding hole 41 is controlled.
With reference to FIG. 2, the second bearing 32 is formed of, for example, a cylindrical roller bearing as a rolling bearing. The 2nd bearing 32 has the outer ring | wheel 65 and the rolling element 66 which consists of a some roller. The outer ring 65 of the second bearing 32 is fitted into the inner periphery of the second holding hole 42 of the housing 13 in a press-fit state. The plurality of rolling elements 66 of the second bearing 32 form an annular shape and surround the second shaft portion 28 of the pinion shaft 7.

The electric power steering apparatus 1 of the present embodiment has a retaining ring mounting structure 68 (hereinafter also simply referred to as a mounting structure 68) for mounting the retaining ring 50 to the housing 13. The mounting structure 68 restricts the movement of the outer ring 52 of the first bearing 31 as an object in the axial direction A2. Hereinafter, the outer ring 52 of the first bearing 31 is also referred to as an object.
The mounting structure 68 includes the first holding hole 41 that holds the outer ring 52 of the first bearing 31 and the retaining ring that positions the first bearing 31 in the axial direction A2 of the first holding hole 41. 50 and the above-described inner peripheral groove 47 formed on the inner periphery of the first holding hole 41. A retaining ring 50 is fitted in the inner circumferential groove 47.

FIG. 4 is an enlarged view of a main part of FIG. FIG. 5 is a front view of the retaining ring 50 shown in FIG. 4 and 5, the retaining ring 50 includes an annular main body 70 and a plurality of protrusions 71 protruding from the main body 70. The main body 70 and the plurality of protrusions 71 are integrally formed of a single material, for example, steel.
The main body 70 has a C-shape or an arc shape when viewed in the axial direction of the retaining ring 50 (corresponding to a direction parallel to the above-described axial directions A1 and A2). The main body 70 has a first end surface 72 and a second end surface 73.

The first end surface 72 is a plane perpendicular to the axial direction of the retaining ring 50. The first end surface 72 is in contact with the end surface 63 of the outer ring 52 of the first bearing 31.
The second end surface 73 has an annular flat surface 74 orthogonal to the axial direction of the retaining ring 50 and a conical tapered cam surface 75. The cam surface 75 is disposed radially outward from the plane 74. The conical taper-shaped central axis of the cam surface 75 is disposed parallel to the axial direction of the retaining ring 50.

Further, the main body 70 of the retaining ring 50 has a pair of end portions 76 that are spaced apart from each other in the circumferential direction C3 of the retaining ring 50 and a pair of engagement holes 77. Each of the pair of end portions 76 has an engagement hole 77.
The pair of engagement holes 77 can be engaged with a jig (not shown) for attaching or removing the retaining ring 50 to or from the inner circumferential groove 47. The retaining ring 50 can be easily reduced in diameter by engaging the jig with the pair of engaging holes 77, and the retaining ring 50 can be attached to and detached from the inner circumferential groove 47 in this state.

  The main body 70 can be elastically bent. For example, the main body 70 is elastically bent and deformed so that the pair of end portions 76 in the circumferential direction C3 are close to each other as compared with a natural state where the main body 70 is not elastically bent and deformed. In this state, the main body 70 is contracted in the radial direction. The retaining ring 50 is fitted in the inner circumferential groove 47 in a state where the main body 70 is elastically contracted in the radial direction. Thus, an elastic restoring force is always applied to the main body 70 of the retaining ring 50 fitted in the inner circumferential groove 47 so that the main body 70 expands in the radial direction.

  The cam surface 75 is formed in a conical taper shape on the second end surface 73 of the retaining ring 50 on the side opposite to the first bearing 31. The cam surface 75 is inclined at a predetermined angle with respect to the axial direction A1 of the pinion shaft 7 in a cross section (axial cross section) including the central axis of the pinion shaft 7. In the above-described axial cross section (corresponding to FIG. 4), the cam surface 75 is inclined so as to approach the first bearing 31 with respect to the axial direction A1 as it goes outward in the radial direction of the retaining ring 50. .

The protrusions 71 protrude from the cam surface 75 and are arranged at a plurality of places, for example, four places, equally spaced in the circumferential direction C3 of the retaining ring 50. The number of protrusions 71 is not limited to four as will be described later. In the present embodiment, a description will be given according to the case of four protrusions 71.
Each protrusion 71 is disposed adjacent to the outer peripheral edge 751 of the cam surface 75. Thereby, the protrusion 71 can be easily disposed in the inner circumferential groove 47.

  Each protrusion 71 has the same shape as each other. For example, each protrusion 71 has a circular shape when viewed in the protruding direction. Each protrusion 71 has a tapered shape. The protrusion amount of the protrusion 71 from the cam surface 75 is a value within the range of 0.3 to 0.7 mm, for example, about 0.5 mm. When the protrusion amount is a value within the above range, the protrusion 71 can be easily disposed in the inner circumferential groove 47.

  The inner circumferential groove 47 is formed in an endless manner continuously in the circumferential direction of the first holding hole 41 of the pinion housing 39 of the housing 13. The inner circumferential groove 47 includes a first inner wall surface 81 that faces the first end surface 72 of the retaining ring 50, a second inner wall surface 82 that faces the second end surface 73 of the retaining ring 50, and an annular groove 83. Is included. The annular groove 83 is formed in the second inner wall surface 82 of the inner circumferential groove 47. A conical tapered cam surface 84 is formed on the second inner wall surface 82.

  The annular groove 83 extends continuously and endlessly in the circumferential direction of the first holding hole 41. The annular groove 83 includes a third inner wall surface 85 having a relatively small diameter L1 and a fourth inner wall surface 86 having a relatively large diameter L2 (L1 <L2). The third inner wall surface 85 of the annular groove 83 is disposed away from the second large diameter portion 48 as the inner periphery of the first holding hole 41 in the radial direction of the first holding hole 41.

The cam surface 84 is formed in the same conical taper shape as the cam surface 75. The cam surface 84 is disposed so as to be in contact with the cam surface 75.
Please refer to FIG. 3 and FIG. 3 and 4 show a normal time when the external force in the axial direction A2 does not act on the pinion shaft 7. FIG. At this normal time, the first end surface 72 of the retaining ring 50 is in contact with the end surface 63 of the outer ring 52 of the first bearing 31. Further, the cam surface 75 of the second end surface 72 of the retaining ring 50 and the cam surface 84 of the inner circumferential groove 47 are aligned with each other. Thus, the first bearing 31 is positioned by the end wall 46 and the cam surface 84 on both sides in the axial direction A2.

  Further, the retaining ring 50 is fitted in the inner circumferential groove 47 in a state of being elastically reduced in diameter. Therefore, a force (elastic restoring force) that elastically expands the retaining ring 50 is generated in the retaining ring 50. By the pair of conical tapered cam surfaces 75 and 84, the elastic restoring force described above is converted into a force that presses the retaining ring 50 against the end surface 63 of the outer ring 52. As a result, since the first bearing 31 is positioned in a state of being pressed in the axial direction A2, the rattling of the first bearing 31 in the axial direction A2 is reliably suppressed.

Further, at normal times, each protrusion 71 is disposed in the annular groove 83 of the inner circumferential groove 47. A gap 87 in the radial direction of the first holding hole 41 is formed between the protrusion 71 and the third inner wall surface 85 of the annular groove 83. At the same time, a gap 88 in the radial direction of the first holding hole 41 is formed between the protrusion 71 and the fourth inner wall surface 86 of the annular groove 83.
FIG. 6 is an enlarged view of the main part of FIG. 2 and shows a case where an external force in the axial direction A1 is applied. Referring to FIG. 6, an external force in the axial direction A1 may act on the retaining ring 50 via the object against the force that presses the retaining ring 50 against the object. Specifically, the above-described external force is road surface input that acts on the wheel from the road surface so as to push up the wheel.

  At this time, when the retaining ring 50 is reduced in diameter by a minute predetermined amount L3, at least one protrusion 71 is engaged with the third inner wall surface 85 of the annular groove 83. Thereby, the shrinkage | contraction of the retaining ring 50 of the quantity exceeding the above-mentioned predetermined amount L3 is controlled regarding the radial direction of the retaining ring 50, and the axial direction movement of the retaining ring 50 is controlled with this. As a result, even when an external force is applied, rattling of the first bearing 31 and the pinion shaft 7 in the axial direction A2 is reliably suppressed.

Here, the predetermined amount L3 corresponds to a length corresponding to the gap amount of the gap 87 in the radial direction of the retaining ring 50.
As described above with reference to FIGS. 3 and 4, in the retaining ring mounting structure 68 of the present embodiment, the first holding hole for holding the outer ring 52 of the first bearing 31 as an object. A retaining ring 50 for positioning the above-described object in the axial direction A2 of 41 is provided. The retaining ring 50 is fitted in an inner circumferential groove 47 formed in the first large-diameter portion 44 as the inner circumference of the first holding hole 41.

In the retaining ring mounting structure 68, the retaining ring 50 includes an annular main body 70 having first and second end faces 72 and 73. The first end surface 72 is in contact with the above-described object, and the projection 71 is formed on the second end surface 73. The inner circumferential groove 47 includes a first inner wall surface 81 that faces the first end surface 72 and a second inner wall surface 82 that faces the second end surface 73.
A protrusion 71 formed on the second end surface 73 of the main body 70 is disposed in an annular groove 83 formed on the second inner wall surface 82 of the inner peripheral groove 47. A pair of conical tapered cam surfaces 75 and 84 are formed along the second end surface 73 of the main body 70 and the second inner wall surface 82 of the inner peripheral groove 47. The pair of conical tapered cam surfaces 75 and 84 function to convert the force that the retaining ring 50 expands elastically into the force that presses the retaining ring 50 against the object. The annular groove 83 includes a third inner wall surface 85 having a relatively small diameter L1 and a fourth inner wall surface 86 having a relatively large diameter L2. The protrusion 71 is engaged with the third inner wall surface 85 of the annular groove 83, so that the contraction of the retaining ring 50 exceeding the predetermined amount L <b> 3 is restricted.

  According to the present embodiment, the force by which the retaining ring 50 expands due to elastic restoration is the function of the pair of cam surfaces 75 and 84, and the retaining ring 50 is moved along the axial direction A <b> 2 of the first holding hole 41. Therefore, rattling of the object in the axial direction A2 can be suppressed. Further, when an external force (for example, road surface input) that pushes the object in the axial direction A2 described above acts on the retaining ring 50 and causes the retaining ring 50 to contract by a predetermined amount L3, the protrusion 71 is the third groove 83 in the annular groove 83. Engage with the inner wall surface 85. Thereby, since the shrinkage | contraction of the quantity exceeding the above-mentioned predetermined amount L3 of the retaining ring 50 is controlled, the shakiness of the target object regarding the above-mentioned axial direction A2 can be suppressed reliably.

In the present embodiment, a gap 88 is formed between the protrusion 71 and the fourth inner wall surface 86 of the annular groove 83. In this case, since the retaining ring 50 can be sufficiently expanded in the inner circumferential groove 47, the rattling of the object is more reliably suppressed.
Referring to FIGS. 4 and 5, the retaining ring 50 has a pair of end portions 76 that are separated in the circumferential direction C <b> 3 of the retaining ring 50. The protrusion 71 is disposed at least on the pair of end portions 76. In this case, when the projections 71 arranged on the pair of end portions 76 are engaged with the third inner wall surface 85 of the annular groove 83, the contraction of the retaining ring 50 is effective so that the entire shape of the retaining ring 50 is destroyed. Regulated. Therefore, it is possible to more reliably suppress the rattling of the object in the axial direction A2 described above.

In general, when the retaining ring 50 is attached to the inner circumferential groove 47, the work is performed while holding the pair of end portions 76 with a jig engaged with the engagement holes 77 of the pair of end portions 76. Therefore, when the jig is used, the protrusion 71 adjacent to the jig is easily engaged with the annular groove 83.
Referring to FIG. 2, an electric power steering device 1 as a vehicle steering device of the present embodiment includes (a1) a steering mechanism 11 that converts rotation of the pinion shaft 7 into axial movement of the rack shaft 10, and (a2 And a first bearing 31 as an object that is held in the first holding hole 41 of the housing 13 and rotatably supports the pinion shaft 7. The axial movement of the first bearing 31 is regulated using the retaining ring mounting structure 68 of the present embodiment.

  According to the present embodiment, for example, when reverse input as an external force acts on the first bearing 31 from the wheel via the rack shaft 10 and the pinion shaft 7, the movement of the retaining ring 50 in the axial direction A2 is restricted. Is done. Thereby, since the shakiness of the first bearing 31 and the pinion shaft 7 in the axial direction A2 is suppressed, the generation of noise due to the axial movement of the pinion shaft 7 can be suppressed. Specifically, it is possible to suppress the generation of rattle noise when traveling on rough roads. In addition, since the effect of suppressing the generation of this abnormal noise can be achieved with a simple structure in which the projection 71 of the retaining ring 50 and the annular groove 83 are engaged, the electric power steering device 1 can be made inexpensive.

  Note that at least one protrusion 71 is sufficient, but a plurality of protrusions 71 is more preferable. For example, in the first case where only the two protrusions 71 disposed on the pair of end portions 76 are engaged with the third inner wall surface 85 of the annular groove 83, the two protrusions 71 disposed on a distance from the end portion 76 are performed. The second case where only the protrusion 71 is engaged with the third inner wall surface 85 of the annular groove 83 will be compared. In the first case, as compared with the second case, the overall shape of the retaining ring 50 is less likely to collapse, so that the contraction of the retaining ring 50 is effectively regulated.

Therefore, when forming at least two protrusions 71, it is preferable that the at least two protrusions 71 include two protrusions 71 formed on the pair of end portions 76. Further, in this case, the larger the number of the protrusions 71, the more reliably the contraction of the retaining ring 50 can be regulated.
Although not shown, it is also conceivable that the protrusion is a protrusion extending in the circumferential direction of the retaining ring 50. For example, the above-described protrusions extend in an arc shape continuously between the pair of end portions 76 along the outer peripheral edge of the main body 70. In addition, the above-described relationship regarding the number and arrangement of protrusions is the same for each embodiment described later.

Moreover, the following modifications can be considered about this embodiment. In the following description, the difference from the above-described embodiment will be mainly illustrated, and this point will be mainly described. Although explanation is omitted about other composition, it is the same as that of the above-mentioned embodiment, and attaches the same numerals.
For example, FIG. 7 is a cross-sectional view of a main part of the electric power steering apparatus 1 as a vehicle steering apparatus to which the retaining ring mounting structure 68 of the second embodiment of the present embodiment is applied. Referring to FIG. 7, the attachment structure 68 of the present embodiment has a retaining ring 50 </ b> A shown in FIG. 7 instead of the retaining ring 50 of the attachment structure 68 of the first embodiment shown in FIG. 3. The retaining ring 50A has a protrusion 71A shown in FIG. 7 instead of the protrusion 71 of the retaining ring 50 of the first embodiment shown in FIG. The retaining ring 50A and the projection 71A are different from the retaining ring 50 and the projection 71 of the first embodiment in the following points, and the other configurations are the same. The protrusion 71 </ b> A is spaced from the outer peripheral edge 751 of the cam surface 75 of the main body 70 of the retaining ring 50 </ b> A with respect to the radial direction of the retaining ring 50 </ b> A and is disposed radially inward from the outer peripheral edge 751.

When the protrusion 71A is disposed radially inward from the outer peripheral edge 751, the annular groove 83 in which the protrusion 71A is disposed is disposed close to the radially inner edge of the inner circumferential groove 47. . As a result, the annular groove 83 is easily formed.
FIG. 8 is a cross-sectional view of a main part of the electric power steering apparatus 1 as a vehicle steering apparatus to which the retaining ring mounting structure 68 of the third embodiment of the present embodiment is applied. Referring to FIG. 8, the attachment structure 68 of this embodiment is replaced with the retaining ring 50, the second inner wall surface 82 of the inner circumferential groove 47, and the inner circumferential groove 83 of the first embodiment shown in FIG. 3. 8 has a retaining ring 50B, a second inner wall surface 82B of the inner circumferential groove 47, and an annular groove 83B.

The retaining ring 50B, the second inner wall surface 82B, and the annular groove 83B of the present embodiment are different from the retaining ring 50, the second inner wall surface 82, and the annular groove 83 of the first embodiment in the following points. The configuration is the same.
The retaining ring 50B has a protrusion 71B shown in FIG. 8 instead of the protrusion 71 of the retaining ring 50 of the first embodiment shown in FIG. The top of the protrusion 71B has a cam surface 75.

The second inner wall surface 82B is formed in a conical taper shape, but does not engage with the cam surface 75 and does not function as the cam surface 84 described above.
The annular groove 83 </ b> B has a third inner wall surface 85, a fourth inner wall surface 86, and a bottom 89. The bottom 89 has a conical taper shape. The above-described cam surface 84 is formed on the bottom 89. The cam surface 84 and the cam surface 75 are aligned with each other and engaged with each other.

When the protrusion 71B having the cam surface 75 at the top is increased, the cam surface 75 is also increased. It becomes easy to ensure both the area of the cam surface 75 and the strength of the protrusion 71B.
Further, the second embodiment may be applied to the retaining ring 50B of the third embodiment. Specifically, the protrusion 71B may be formed to be spaced radially inward from the outer peripheral edge of the retaining ring 50B.
FIG. 9 is a cross-sectional view of a main part of the electric power steering apparatus 1 as a vehicle steering apparatus to which the retaining ring mounting structure 68 of the fourth embodiment of the present embodiment is applied. Referring to FIG. 9, the attachment structure 68 of this embodiment has a retaining ring 50 </ b> C shown in FIG. 9 instead of the retaining ring 50 of the attachment structure 68 of the first embodiment shown in FIG. 3. The retaining ring 50C is different from the retaining ring 50 of the first embodiment in the following points, and the other configurations are the same.

  The retaining ring 50C has a first end face 72C shown in FIG. 9 instead of the first end face 72 of the retaining ring 50 of the first embodiment shown in FIG. The first end surface 72 </ b> C is configured in the same manner as the second end surface 73. The first end surface 72C and the second end surface 73 are symmetrical in FIG. 9 and are symmetrical with respect to a symmetry plane P1 that passes through the center position in the axial direction of the retaining ring 50 and is orthogonal to the axial direction of the retaining ring 50. Is formed.

Thereby, even if the reverse side of the retaining ring 50C is reversed and attached to the inner circumferential groove 47, the retaining ring 50C can be used without any problem. Since it can be assembled into the inner circumferential groove 47 without paying attention to the front and back of the retaining ring 50C, the retaining ring 50C can be easily assembled.
That is, the first end surface 72C has a flat surface 74, a cam surface 75, and a plurality of protrusions 71 (only one is shown). When the first end surface 72 </ b> C faces the second inner wall surface 82 of the inner peripheral groove 47, the protrusion 71 of the first end surface 72 </ b> C is disposed in the annular groove 83 of the inner peripheral groove 47. The protrusion 71 of the first end surface 72C is engaged with the third inner wall surface 85, so that the contraction of the retaining ring 50C is restricted. Further, the cam surface 75 of the first end surface 72 </ b> C and the cam surface 84 of the second inner wall surface 82 of the inner circumferential groove 47 are arranged along each other.

Further, although not shown, like the fourth embodiment, the first end surface 72 of the second embodiment in FIG. 7 is similar to the second end surface 73 in that the cam surface 75, the plurality of protrusions 71A, You may have. Moreover, the 1st end surface 72 of 3rd Embodiment of FIG. 8 may have the cam surface 75 and several protrusion 71B similarly to the 2nd end surface 73. FIG.
In addition, each retaining ring of each of the above-described embodiments may be a retaining ring of a type without an engagement hole for a jig, a so-called C-shaped concentric retaining ring.

  In each of the above-described embodiments, the example in which the present invention is applied to the so-called column assist type electric power steering apparatus 1 has been described, but the present invention is not limited thereto. For example, the present invention may be applied to a so-called pinion assist type electric power steering device or a so-called rack assist type electric power steering device. In addition, various changes can be made within the scope of the matters described in the claims.

1 is a schematic diagram of a schematic configuration of an electric power steering device as a vehicle steering device to which a retaining ring mounting structure according to a first embodiment of the present invention is applied. It is sectional drawing of the principal part of the electric power steering apparatus of FIG. It is an enlarged view of the principal part of FIG. 2, and shows the normal time when the external force of an axial direction is not acting. It is an enlarged view of the principal part of FIG. It is a front view of the retaining ring shown in FIG. It is an enlarged view of the principal part of FIG. 2, and shows the time when the external force of an axial direction acts. It is sectional drawing of the principal part of the electric power steering apparatus as a vehicle steering device to which the retaining ring mounting structure of the 2nd Embodiment of this invention is applied. It is sectional drawing of the principal part of the electric power steering apparatus as a vehicle steering device to which the retaining ring mounting structure of the 3rd Embodiment of this invention is applied. It is sectional drawing of the principal part of the electric power steering apparatus as a vehicle steering device to which the retaining ring mounting structure of the 3rd Embodiment of this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device (vehicle steering device), 7 ... Pinion shaft, 10 ... Rack shaft, 11 ... Steering mechanism, 13 ... Housing, 31 ... First bearing (object), 41 ... First holding hole 44 ... first large diameter part (inner circumference of holding hole), 47 ... inner circumferential groove, 50, 50A, 50B, 50C ... retaining ring, 68 ... attachment structure of retaining ring, 70 ... main body, 71, 71A, 71B ... projection, 72, 72C ... first end face, 73, 73B ... second end face, 75, 84 ... cam face, 76 ... end of retaining ring, 81 ... first inner wall face, 82, 82B ... first 2, inner wall surfaces 83, 83B ... annular groove, 85 ... third inner wall surface, 86 ... fourth inner wall surface, 88 ... gap (gap between the protrusion and the fourth inner wall surface), 89 ... annular groove Bottom, A2 ... axial direction (axial direction of holding hole), C3 ... circumferential direction of retaining ring, L1 ... diameter of the third inner wall surface, L2 Diameter of the fourth inner wall surface, L3 ... predetermined amount.

Claims (4)

In the retaining ring mounting structure, a retaining ring for positioning the object in the axial direction of the retaining hole for retaining the object is fitted in an inner circumferential groove formed on the inner periphery of the retaining hole.
The retaining ring includes an annular main body having first and second end faces,
The first end surface abuts on the object, and a protrusion is formed on the second end surface. The inner circumferential groove includes a first inner wall surface facing the first end surface, and the second end surface. A second inner wall face facing the end face,
The protrusion formed on the second end surface of the main body is disposed in an annular groove formed on the second inner wall surface of the inner circumferential groove;
A pair of conical tapered cam surfaces are formed along the second end surface of the main body and the second inner wall surface of the inner circumferential groove, or the bottoms of the protrusions and the annular groove In addition, a pair of conical tapered cam surfaces are formed along each other,
The pair of conical tapered cam surfaces function to convert the force that the retaining ring elastically expands into the force that presses the retaining ring against the object;
The annular groove includes a third inner wall surface having a relatively small diameter and a fourth inner wall surface having a relatively large diameter,
A retaining ring mounting structure, wherein the projection is engaged with the third inner wall surface of the annular groove so that contraction exceeding a predetermined amount of the retaining ring is restricted.   2. The retaining ring mounting structure according to claim 1, wherein a gap is formed between the protrusion and the fourth inner wall surface of the annular groove.   3. The retaining ring according to claim 1, wherein the retaining ring has a pair of end portions that are spaced apart from each other in the circumferential direction of the retaining ring, and the protrusion is disposed at least at the pair of end portions. Retaining ring mounting structure. A steering mechanism that converts rotation of the pinion shaft into axial movement of the rack shaft;
A bearing as the object that is held in the holding hole of the housing and rotatably supports the pinion shaft;
A vehicle steering apparatus, wherein the retaining ring mounting structure according to any one of claims 1 to 3 is used to restrict axial movement of the bearing.

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