JP5954574B2 - Rack shaft support device and steering device using the same - Google Patents

Description

  The present invention relates to a rack shaft support device and a steering device using the same.

  In the rack and pinion type steering device, when the support yoke that slidably supports the rack shaft is worn, the cam is rotated by an elastic member to compensate for the gap between the support yoke and the plug. An adjustment device is provided (see, for example, Patent Document 1).

JP 2008-296899 A

In Patent Document 1, since the engagement surface between the cam and a member that rotates relative to the cam slides relative to the surface, great frictional resistance is given to the rotation of the cam. For this reason, when the support yoke is worn, there is a possibility that the cam cannot rotate and the gap cannot be compensated.
In this case, since the set length of the yoke spring that urges the support yoke toward the rack shaft side increases, the urging load that urges the rack shaft toward the pinion side via the support yoke decreases. As a result, the pressing force of the meshing portion between the rack and the pinion is lowered, and there is a possibility that noise due to abnormal noise is generated between the rack and the pinion.

  Accordingly, an object of the present invention is to provide a rack shaft support device that can reliably compensate for the biasing load to the pinion side when wear occurs and can reliably suppress the generation of abnormal noise, and a steering device using the same. It is.

In order to achieve the object, the invention of claim 1 is accommodated in the holding hole (16) of the housing (17) so as to be slidable in the depth direction (X1) of the holding hole and sliding the rack shaft (8). A rack shaft supporting member (18) that is movably supported, a closing member (19; 119) fixed to the housing and closing the holding hole, and interposed between the rack shaft supporting member and the closing member, An urging member (27) for elastically urging the rack shaft support member toward the rack shaft side, and interposed between the rack shaft support member and the closing member, and the center axis (C1) of the holding hole A first intermediate member (20; 120) that can rotate around and a second intermediate member (21; 121) that cannot rotate, one of the closing member and the second intermediate member, and the first intermediate member. Engage and apply a rotational force (R) to the first intermediate member Cam surface (22; 122) and a cam surface (20a, 21b; 120b, 121a) provided on at least one of the opposing surfaces (20a, 21b; 120b, 121a) and inclined with respect to the rotational direction of the first intermediate member. 23, 24; 123, 124) and a rolling element (25; 125) engaged with the cam surface between the opposing surfaces of both intermediate members, for relative rotation of both intermediate members by the rotational force biasing spring. And a cam mechanism (26; 126) for increasing the total length of both intermediate members in the depth direction, and holding the rolling elements with a predetermined holding force on the cam surface. A rack shaft support device (15; 115) provided with a return restraining recess (40; 140) for restraining the rolling element from returning along the axis is provided.

In addition, although the alphanumeric character in a parenthesis represents the corresponding component etc. in embodiment mentioned later, this does not mean that this invention should be limited to those embodiment as a matter of course. The same applies hereinafter .

According to a second aspect of the present invention, a plurality of the return suppression recesses may be provided apart from each other in the inclination direction of the cam surface.
According to a third aspect of the present invention, the biasing member is interposed between the intermediate member facing the closing member and the closing member among the intermediate members, and the rack shaft support member is inserted through the intermediate members. It may be elastically biased toward the rack shaft side.

According to a fourth aspect of the present invention, the first intermediate member is disposed to face the rack shaft support member, and is a low friction plate (28) interposed between opposed surfaces of the rack shaft support member and the first intermediate member. ) Or a low friction portion provided on at least one of the opposing surfaces.
According to a fifth aspect of the present invention, there is provided a steering device (1) for supporting the rack shaft so as to be slidable in the axial direction (Z1) using the rack shaft supporting device.

  According to the first aspect of the present invention, since the cam mechanism uses the rolling element that engages with the cam surface, when the rack shaft support member on which the rack shaft slides wears, both intermediate members respond. The relative rotation is performed smoothly with good performance to increase the total length of both intermediate members in the depth direction. This reliably compensates for a decrease in the urging load of the urging member due to an increase in the set length of the urging member due to wear. That is, regardless of the occurrence of wear, the set length of the biasing member can be reliably maintained substantially constant, and the biasing load of the biasing member can be reliably maintained substantially constant. Can be maintained substantially constant and noise generation can be reliably suppressed.

Moreover , the relative rotational position of both intermediate members can be stabilized in a state where the rolling element is held in the holding recess of the cam surface with a predetermined holding force.
According to invention of Claim 2 , the relative rotational position of both the intermediate members can be stabilized in several steps.
According to the invention of claim 3 , since the rack shaft support member is elastically urged toward the rack shaft side via the intermediate members by the urging member, the rolling element interposed between the opposing surfaces of the intermediate members is included. The operation of the cam mechanism can be stabilized.

According to invention of Claim 4, since a 2nd intermediate member can be rotated more smoothly, the full length of both intermediate members can be increased more reliably and noise generation can be suppressed more reliably.
According to the invention of claim 5 , it is possible to realize a steering device that can reliably suppress the generation of abnormal noise over a long period of time.

1 is a schematic diagram showing a schematic configuration of a rack and pinion type steering device according to an embodiment of the present invention. It is sectional drawing of the principal part of the steering apparatus with which the rack shaft support apparatus was applied. It is an expanded sectional view of a rack shaft support device. It is a front view of the 1st rotatable intermediate member which engaged the some rolling element. It is a rear view of the 2nd intermediate member. It is a top view of the holder | retainer holding a some rolling element. It is sectional drawing of a cam mechanism, and has shown the state before wear compensation. It is sectional drawing of a cam mechanism, and has shown the state after wear compensation. It is an expanded sectional view of the rack shaft support device of another embodiment of the present invention. In the embodiment of FIG. 8, it is sectional drawing of a cam mechanism, and has shown the state before wear compensation. In the embodiment of FIG. 8, it is sectional drawing of a cam mechanism, and has shown the state after wear compensation. FIG. 9 is a front view of a non-rotatable second intermediate member that engages a plurality of rolling elements in the embodiment of FIG. 8. FIG. 9 is a rear view of the rotatable first intermediate member in the embodiment of FIG. 8. It is sectional drawing of the cam mechanism of further another embodiment of this invention, and has shown the example by which the some return suppression recessed part was provided in one cam surface. It is sectional drawing of the cam mechanism of further another embodiment of this invention, and the example in which the return suppression recessed part was received on both cam surfaces is shown.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
Referring to FIG. 1, a steering device 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, and an intermediate shaft 5 A rack shaft 8 as a steered shaft extending in the left-right direction of the automobile having a pinion shaft 7 connected to the vehicle through a universal joint 6 and a rack 8a meshing with the pinion 7a provided in the vicinity of the end of the pinion shaft 7 And have. The pinion shaft 7 and the rack shaft 8 constitute a rack and pinion mechanism A as a steering mechanism.

  The rack shaft 8 is supported in a rack housing 9 fixed to the vehicle body through a plurality of bearings (not shown) so as to be linearly reciprocable along the axial direction Z1. Both end portions of the rack shaft 8 protrude to both sides of the rack housing 9, and tie rods 10 are coupled to the respective end portions. Each tie rod 10 is connected to a corresponding steered wheel 11 via a corresponding knuckle arm (not shown).

When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion in the axial direction Z1 of the rack shaft 8 by the pinion 7a and the rack 8a. Thereby, the turning of the steered wheel 11 is achieved.
Referring to FIG. 2, the pinion shaft 7 is rotatably supported in the pinion housing 14 by a first bearing 12 made of, for example, a ball bearing and a second bearing 13 made of, for example, a cylindrical roller bearing. The pinion 7 a of the pinion shaft 7 and the rack 8 a of the rack shaft 8 are meshed with each other in the pinion housing 14.

  The steering device 1 is equipped with a rack shaft support device 15. The rack shaft support device 15 includes a housing 17 having a holding hole 16 formed of a circular hole, and is accommodated in the holding hole 16 so as to be slidable along the depth direction X1 of the holding hole 16 and the rear surface of the rack 8a of the rack shaft 8. A support yoke 18 as a rack shaft support member that slidably supports 8b, and a closing member 19 made of, for example, a plug (plug) that is fixed to the housing 17 and closes the inlet of the holding hole 16 are provided.

The rear surface 18b of the support yoke 18 and the front surface 19a of the closing member 19 are separated by a distance L1. The distance L1 increases as wear of the support yoke 18 (specifically, a sliding contact plate 30 described later) on which the rack shaft 8 slides increases.
The housing 17 of the rack shaft support device 15 is formed integrally with the pinion housing 14 from a single material, and is disposed on the opposite side of the pinion shaft 7 with the rack shaft 8 therebetween. The pinion housing 14 and the housing 17 are manufactured by die casting, for example.

  As shown in FIGS. 2 and 3, the rack shaft support device 15 includes a first intermediate member 20 and a second intermediate member 21 provided between the support yoke 18 and the closing member 19, and the closing member 19. A rotational force biasing spring 22 that engages with the first intermediate member 20 and applies a rotational force around the central axis C1 of the holding hole 16 to the first intermediate member 20, and the first intermediate member 20 as shown in FIG. 7A. Between the cam surfaces 23 and 24 and the cam surfaces 23 and 24 provided on the opposing surfaces (the front surface 20a of the first intermediate member 20 and the rear surface 21b of the second intermediate member 21), respectively. For example, a cam mechanism 26 including a metal rolling element 25 is provided.

Referring to FIG. 3, the first intermediate member 20 and the second intermediate member 21 have a columnar shape or a cylindrical shape, and the outer periphery 20c of the first intermediate member 20 and the outer periphery 21c of the second intermediate member 21 are cylindrical surfaces. And is fitted to the inner periphery 16 a of the holding hole 16.
In the present embodiment, as shown in FIG. 7A, a description will be given based on an example in which cam surfaces 23 and 24 are formed on both the front surface 20 a of the first intermediate member 20 and the rear surface 21 b of the second intermediate member 21. The cam surface may be formed on only one of the front surface 20 a of the first intermediate member 20 and the rear surface 21 b of the second intermediate member 21. The rolling element 25 may be a ball, or may be a roller such as a cylindrical roller, a cylindrical roller, or a tapered roller. In this embodiment, the rolling element 25 will be described based on the case where the rolling element 25 is a ball.

Referring to FIG. 3, for example, one end 22 a of the rotational force biasing spring 22 is engaged with the closing member 19, the other end 22 b is engaged with the first intermediate member 20, and the one end 22 a and the other end 22 b are connected. It consists of a torsion coil spring that stores a torsional force (rotational force) around the central axis C1 of the holding hole 16.
The rotational force biasing spring 22 is accommodated so as to straddle the recess 19 d provided on the front surface 19 a of the closing member 19 and the recess 20 d provided on the rear surface 20 a of the first intermediate member 20. One end 22a of the rotational force biasing spring 22 is locked to the bottom of the recess 19d, and the other end 22b of the rotational force biasing spring 22 is locked to the bottom of the recess 20d. Only one of the recess 19d and the recess 20d may be provided.

The rack shaft support device 15 is interposed between the closing member 19 and the first intermediate member 20 in a compressed state having a set length L3, and the support yoke 18 is moved to the rack shaft 8 side via both intermediate members 20 and 21. A biasing member 27 that biases elastically is provided. As the urging member 27, a disc spring as shown in FIG. 2 or a compression spring such as a compression coil spring may be used.
A low friction plate 28 is interposed between the biasing member 27 and the rear surface 20 b of the first intermediate member 20. The low friction plate 28 may be a resin plate formed of a low friction material such as fluororesin, or may be a metal plate whose surface is coated with a low friction material such as fluororesin. Although not shown, instead of the low friction plate 28, the first intermediate member 20 includes a rear surface 20b and a fluororesin layer coated on at least one of the surfaces of the urging member 27 facing the rear surface 20b. A low friction part may be used.

  Although not shown, a low friction plate interposed between the urging member 27 and the front surface 19a of the closing member 19 may be provided instead of or in combination with the low friction plate 28, Further, instead of the low friction plate, a low friction portion constituted by a fluororesin layer or the like coated on at least one of the front surface 19a of the closing member 19 and the surface of the biasing member 27 facing the front surface 19a is used. Also good.

  The support yoke 18 as a rack shaft support member has a front surface 18a facing the rack shaft 8, a rear surface 18b facing the second intermediate member 20, and an outer periphery 18c made of a cylindrical surface. On the front surface 18 a of the support yoke 18, a concave surface 28 having a shape substantially coinciding with the shape of the back surface 8 b of the rack shaft 8 is formed. A curved sliding contact plate 30 is attached along the concave surface 29, and the sliding contact plate 30 is in sliding contact with the back surface 8 b of the rack shaft 8. As the sliding contact plate 30, it is preferable to use a plate having a low friction coefficient, and for example, a metal plate or a metal plate coated with a fluororesin can be used.

A sealing member 52 made of an annular elastic member such as an O-ring is accommodated and held in an annular accommodation groove 51 provided on the outer periphery 18c of the support yoke 18. The sealing member 52 functions to seal between the outer periphery 18 c of the support yoke 18 and the inner periphery 16 a of the holding hole 16.
The closing member 19 includes a plug having a front surface 19a and a rear surface 19b with respect to the depth direction X1. That is, a male screw 31 is formed on the outer periphery 19 c of the closing member 19. On the other hand, on the inner periphery 16a of the holding hole 16, a female screw 16b is formed at the inlet of the holding hole 16, and the male screw 31 of the closing member 19 is screwed and fixed to the female screw portion 16b.

  The rear surface 19b of the closing member 19 is provided with a tool engaging hole 32 having a polygonal cross section with which a tool for screwing the closing member 19 is engaged. A sealing member 54 made of an annular elastic member such as an O-ring is accommodated and held in one or more annular accommodation grooves 53 provided on the outer periphery 19c of the closing member 19. The sealing member 54 functions to seal between the outer periphery 19 c of the closing member 19 and the inner periphery 16 a of the holding hole 16.

The first intermediate member 20 is supported by the inner periphery 16 a of the holding hole 16 so as to be rotatable about the central axis C <b> 1 of the holding hole 16 and displaceable in the depth direction X <b> 1 of the holding hole 16.
One or more engaging grooves 33 extending in the depth direction X1 are provided on the outer periphery 21c of the second intermediate member 21. The engaging groove 33 is engaged with a guide pin 34 that is fixed to the housing 17 and extends in a direction orthogonal to the depth direction X1. The guide pin 34 is fixed by being press-fitted from the outside into a fixing hole 35 that passes through the housing 17 and faces the holding hole 16.

The rotation of the second intermediate member 21 is restricted by the guide pin 34 engaged with the engagement groove 33. Further, the second intermediate member 21 is guided by the guide pin 34 and can be moved back and forth in the depth direction X1.
As shown in FIG. 4, a plurality of arc-shaped holding grooves 36 arranged around the rotation center of the first intermediate member 20 (corresponding to the central axis C <b> 1 of the holding hole 16) are formed on the front surface 20 a of the first intermediate member 20. Is provided. A cam surface 23 is formed at the bottom of each holding groove 36.

Further, as shown in FIG. 5, a plurality of arc-shaped holding grooves arranged around the rotation center of the first intermediate member 20 (corresponding to the central axis C1 of the holding hole 16) on the rear surface 21b of the second intermediate member 21. 37 is provided. A cam surface 24 is formed at the bottom of each holding groove 37. As shown in FIG. 7A, each rolling element 25 made of a ball is accommodated between both holding grooves 36 and 37.
Moreover, as shown in FIG. 6, each rolling element 25 is hold | maintained at the corresponding holding hole 39 of the holder | retainer 38, and the mutual positional relationship is maintained constant. The holding holes 39 are arranged at regular intervals in the circumferential direction of the cage 38. However, the retainer 38 may be eliminated.

As shown in FIG. 7A, the cam surface 23 provided at the bottom of the holding groove 36 on the front surface 20a (opposing surface) of the first intermediate member 20, and the holding groove 37 on the rear surface 21b (opposing surface) of the second intermediate member 21. And the cam surface 24 provided at the bottom of each of them are inclined in opposite directions with respect to the circumferential direction Y1.
Specifically, the cam surface 23 of the rotatable first intermediate member 20 has an inclined surface that approaches the second intermediate member 21 side in the direction opposite to the direction of the rotational force R by the rotational force biasing spring 22. Is formed. Further, the cam surface 24 of the second intermediate member 21 whose rotation is restricted is formed as an inclined surface that approaches the first intermediate member 20 side as it goes in the direction of the rotational force R.

The inclination angle of the cam surfaces 23 and 24 with respect to the circumferential direction Y1 is set to an angle (for example, 1 to 3 degrees) at which the first intermediate member 20 does not rotate in the return direction when receiving reverse input from the rack shaft 8 side. ing.
Further, the cam surface 24 of the second intermediate member 21 returns to the middle part or the terminal part that climbs the slope, and forms a suppression concave part 40. As shown in FIG. 7B, when the rolling element 25 is engaged, the return suppressing recess 40 holds the rolling element 25 with a predetermined holding force, so that the rolling element 25 lowers the inclination of the cam surface 24. It functions to suppress returning to the direction.

  According to the present embodiment, the cam mechanism 26 uses the rolling elements 25 that engage with the cam surfaces 23 and 24 as the opposed surfaces of the intermediate members 20 and 21. When the sliding portion of the support yoke 18 (specifically, the sliding contact plate 30 fixed to the support yoke 18) is worn, both the intermediate members 20 and 21 can be rotated relatively smoothly with good responsiveness. .

  Thereby, the fall of the urging | biasing load of the urging | biasing member 27 by the increase in the set length L3 of the urging | biasing member 27 resulting from abrasion can be compensated reliably. That is, regardless of the occurrence of wear, the set length L3 of the urging member 27 can be reliably maintained substantially constant, and the urging load of the urging member 27 can be reliably maintained substantially constant, so that the rack 8a and the pinion 7a Generation of noise can be reliably suppressed by maintaining the pressing force of the meshing portion substantially constant.

  Specifically, the first intermediate member 20 rotates as shown in FIGS. 7A to 7B by the rotational force R of the rotational force biasing spring 22. The rotational movement of the first intermediate member 20 is performed in the depth direction X1 (support yoke 18 side) via a cam mechanism 26 including both cam surfaces 23, 24 and rolling elements 25 that are in rolling contact with both cam surfaces 23, 24. ) To the linear motion of the second intermediate member 21. As a result, the total length L2 of both the intermediate members 20 and 21 in the depth direction X1 (see FIG. 3; corresponding to the distance between the front surface 21a of the second intermediate member 21 and the rear surface 20b of the first intermediate member 20) increases. As a result, the second intermediate member 21 pushes the support yoke 18 toward the rack shaft 8 side, while the gap between the rear surface 20b of the first intermediate member 20 and the front surface 19a of the closing member 19 (corresponding to the set length L3 of the biasing member 27). ) Can be maintained substantially constant.

In other words, regardless of the increase in the distance L1 between the support yoke 18 (rear surface 18b) and the closing member 19 (front surface 19a) due to the occurrence of wear, the total length L2 of both the intermediate members 20, 21 can be reliably increased, Thus, the set length L3 of the urging member 27 can be reliably maintained substantially constant, and the urging load of the urging member 27 can be reliably maintained substantially constant.
In addition, with the first intermediate member 21 rotated by a predetermined amount, as shown in FIG. 7B, the rolling element 25 can be held in the return restraining recess 40 of the cam surface 24 with a predetermined holding force. The relative rotational positions of 20, 21 can be stabilized. Therefore, when the reverse input from the rack shaft 8 side is received, it can suppress that the relative rotational position of both the intermediate members 20 and 21 is returned to the original.

  Further, the return restraint recess 40 ensures the difficulty of returning the rolling element 25 when receiving reverse input, so that the inclination of the cam surfaces 23 and 24 can be slightly increased. By increasing the inclination of the cam surfaces 23 and 24, the ratio of the amount of movement of the second intermediate member 21 in the depth direction X1 to the amount of rotation of the first intermediate member 20 due to the rotational force of the rotational force biasing spring 22 is increased. Thus, the support yoke 18 can be easily driven to the rack shaft 8 side. As a result, the degree of freedom of design regarding the inclination of the cam surfaces 23 and 24 is increased.

  Further, a biasing member 27 that is elastically compressed between the closing member 19 and the first intermediate member 20 and elastically biases the support yoke 18 via the intermediate members 20 and 21 is provided. Provided. That is, the urging member 27 urges the support yoke 18 toward the rack shaft 8 via the first intermediate member 20, the cam mechanism 26 including the rolling elements 25, and the second intermediate member 21. Therefore, it is possible to suppress the occurrence of rattling or the like in the cam mechanism 26 in which the rolling elements 25 are interposed between the cam surfaces 23 and 24 of the intermediate members 20 and 21, and the operation of the cam mechanism 26 can be stabilized. .

Since the low friction plate 28 is interposed between the urging member 27 and the rear surface 20b of the first intermediate member 20, the first intermediate member 20 can be rotated more smoothly. When wear of the contact plate 30) occurs, the total length L2 of the intermediate members 20 and 21 can be more reliably increased, and the urging load of the urging member 27 can be reliably maintained substantially constant.
Moreover, the steering apparatus 1 which can suppress generation | occurrence | production of abnormal noise for a long period of time using the rack shaft support apparatus 15 is realizable.

8 to 11 show a rack shaft support device 115 according to another embodiment of the present invention. With reference to FIGS. 8 to 11, the present embodiment is mainly different from the embodiments of FIGS. 3 to 7B in the following (1) to (4).
(1) In the embodiment of FIG. 3, the rotatable first intermediate member 20 is disposed to face the closing member 19, and the second intermediate member 21 whose rotation is restricted is disposed to face the support yoke 18. It was.

On the other hand, in the present embodiment, the rotatable first intermediate member 120 is disposed to face the support yoke 18, and the second intermediate member 121 whose rotation is restricted is disposed to face the closing member 119. ing. That is, the first intermediate member 120 is disposed closer to the support yoke 18 than the second intermediate member 121. The outer periphery 120 c of the first intermediate member 120 and the outer periphery 121 c of the second intermediate member 121 are fitted to the inner periphery 16 a of the holding hole 16.
(2) In the embodiment of FIG. 3, the rotational force biasing spring 22 is engaged with the closing member 19 and the first intermediate member 20, and the first intermediate member 20 is rotated with respect to the closing member 19. It had a rotating force to make it. Further, the rotational force biasing spring 22 was accommodated so as to straddle the recess 19 d provided on the front surface 19 a of the closing member 19 and the recess 12 d provided on the rear surface 12 b of the first intermediate member 12.

  On the other hand, in this embodiment, the rotational force biasing spring 122 is engaged with the first intermediate member 120 and the second intermediate member 121, and the first intermediate member 120 is rotated with respect to the second intermediate member 121. Rotating force is exerted. Further, the rotational force biasing spring 122 is accommodated so as to straddle the recess 121d provided on the front surface 121a of the second intermediate member 121 and the recess 120d provided on the rear surface 120b of the first intermediate member 120. Yes.

One end 122a of the rotational force biasing spring 122 is locked to the bottom of the recess 121d, and the other end 122b of the rotational force biasing spring 122 is locked to the bottom of the recess 120d. Only one of the recess 121d and the recess 120d may be provided.
The front surface 119a of the closing member 119 and the rear surface 121b of the second intermediate member 121 are formed as flat surfaces and face each other. Since the front surface 119a of the closing member 119 and the rear surface 121b of the second intermediate member 121 do not rotate relative to each other, the urging member 27 interposed between both surfaces 119a and 121b is in direct contact with both surfaces 119a and 121b. A tool engagement hole 132 is formed in the rear surface 119b of the closing member 119. A male screw 131 that engages with the female screw portion 16 b of the holding hole 16 is provided on the outer periphery 119 c of the closing member 119.
(3) In the embodiment of FIG. 7A, the cam mechanism 26 is formed on the cam surface 23 formed on the front surface 20a of the rotatable first intermediate member 20 and the rear surface 21b of the second intermediate member 21 that cannot rotate. The cam surface 24 is formed, and the rolling element 25 is a ball 25 interposed between the cam surfaces 23 and 24.

In contrast, in the present embodiment, as shown in FIG. 9A, the cam mechanism 126 includes a cam surface 123 formed on the rear surface 120b of the rotatable first intermediate member 120 and a non-rotatable second intermediate member 121. The cam surface 124 is formed on the front surface 121a of the motor and the rolling element 125 made of balls interposed between the cam surfaces 123 and 124.
As shown in FIG. 10, the rolling element 125 includes a plurality of arc-shaped holding grooves 137 disposed on the front surface 121a of the second intermediate member 121 so as to surround the recess 121d, and the first intermediate member 120 as shown in FIG. The rear surface 120b is accommodated and held between the holding groove 136 disposed so as to surround the recess 120d.

As shown in FIG. 9B, the cam surface 123 is provided with a return suppressing recess 140 that holds the rolling element 125 with a predetermined holding force and suppresses the return of the rolling element 125 along the inclination direction of the cam surface 123. ing.
(4) In the embodiment of FIG. 3, the low friction plate 28 is interposed between the front surface 19 a of the closing member 19 and the rear surface 20 b of the rotatable first intermediate member 20. On the other hand, in this embodiment, as shown in FIG. 8, the low friction plate 128 is interposed between the front surface 120 a of the rotatable first intermediate member 120 and the rear surface 18 b of the support yoke 18.

  The low friction plate 128 may be a resin plate formed of a low friction material such as a fluororesin, or may be a metal plate whose surface is coated with a low friction material such as a fluororesin. Although not shown, instead of the low friction plate 128, a low friction portion constituted by a fluororesin layer or the like coated on at least one of the front surface 120a of the first intermediate member 120 and the rear surface 18b of the support yoke 18 is used. Also good.

In the components of the present embodiment, the same reference numerals as those of the embodiments of FIGS. 3 to 7B are assigned to the same components as those of the embodiment of FIGS.
According to the present embodiment, the cam mechanism 126 uses the rolling elements 125 that engage with the cam surfaces 123 and 124 as the opposed surfaces of the intermediate members 120 and 121. When wear occurs on the sliding portion of the support yoke 18 (specifically, the sliding contact plate 30 fixed to the support yoke 18), both the intermediate members 120 and 121 can be rotated relatively smoothly with good responsiveness. .

  Thereby, the fall of the urging | biasing load of the urging | biasing member 27 by the increase in the set length L3 of the urging | biasing member 27 resulting from abrasion can be compensated reliably. In other words, the set length L3 of the urging member 27 can be maintained substantially constant and the urging load of the urging member 27 can be maintained substantially constant regardless of the occurrence of wear, so that the engagement portion between the rack 8a and the pinion 7a can be pushed. Noise can be reliably suppressed by maintaining the pressure substantially constant.

  Specifically, the first intermediate member 120 rotates in the depth direction X1 (support yoke 18 side) by the cam mechanism 126 by the rotational movement of the first intermediate member 120 by the rotational force R of the rotational force biasing spring 122. It is converted into 120 linear motions. Thereby, the total length L2 (corresponding to the distance between the front surface 120a of the first intermediate member 120 and the rear surface 121b of the second intermediate member 121) of both the intermediate members 120 and 121 in the depth direction X1 increases. As a result, the first intermediate member 120 pushes the support yoke 18 toward the rack shaft 8 side, while the gap between the rear surface 121b of the second intermediate member 121 and the front surface 119a of the closing member 119 (corresponding to the set length L3 of the biasing member 27). ) Can be kept substantially constant.

In other words, regardless of the increase in the distance L1 between the support yoke 18 (rear surface 18b) and the closing member 19 (front surface 19a) due to the occurrence of wear, the total length L2 of the intermediate members 120 and 121 can be reliably increased, Thus, the set length L3 of the urging member 27 can be reliably maintained substantially constant, and the urging load of the urging member 27 can be reliably maintained substantially constant.
Further, as shown in FIG. 9B, the rolling element 125 can be held in the return restraining recess 140 of the cam surface 124 with a predetermined holding force with the first intermediate member 120 rotated by a predetermined amount. The relative rotational positions of 120 and 121 can be stabilized. Therefore, when the reverse input from the rack shaft 8 side is received, it is possible to prevent the relative rotational positions of the intermediate members 120 and 121 from being returned to the original positions.

  In addition, the return restraint recess 140 ensures the difficulty of returning the rolling element 125 when receiving reverse input, so that the inclination of the cam surfaces 123 and 124 can be slightly increased. By increasing the inclination of the cam surfaces 123 and 124, the ratio of the amount of movement of the first intermediate member 120 in the depth direction X1 to the amount of rotation of the first intermediate member 120 by the rotational force of the rotational force biasing spring 122 is increased. Thus, the support yoke 18 can be easily driven to the rack shaft 8 side. As a result, the degree of freedom of design regarding the inclination of the cam surfaces 123 and 124 is increased.

  Further, the urging member 27 urges the support yoke 18 toward the rack shaft 8 via the second intermediate member 121, the cam mechanism 126 including the rolling elements 125, and the first intermediate member 120. Therefore, it is possible to suppress the occurrence of rattling or the like in the cam mechanism 126 in which the rolling elements 125 are interposed between the cam surfaces 123 and 124 of the intermediate members 120 and 121, and the operation of the cam mechanism 126 can be stabilized. .

  Since the low friction plate 128 is interposed between the front surface 120a of the rotatable first intermediate member 120 and the rear surface 18b of the support yoke 18, the first intermediate member 120 can be rotated more smoothly. Therefore, when the support yoke 18 (sliding contact plate 30) is worn, the total length L2 of the intermediate members 120 and 121 is more reliably increased, and the urging load of the urging member 27 is reliably maintained substantially constant. can do.

Moreover, the steering apparatus 1 which can suppress generation | occurrence | production of abnormal noise for a long period of time using the rack shaft support apparatus 115 is realizable.
In addition, the present invention is not limited to the above-described embodiment. For example, in the embodiment of FIG. 7A, as shown in FIG. May be provided. Further, in the embodiment of FIG. 7A, as shown in FIG. 13, in addition to the return suppression recess 40 of the cam surface cam surface 24, a return suppression recess 42 is provided on the cam surface 23, and the both return suppression recesses 40, 42 are used together. Then, the rolling element 25 may be held. Although not shown, a return suppression recess 42 may be provided on the cam surface 23 instead of the return suppression recess 40 of the cam surface 24. In other words, at least one of the cam surfaces 23 and 24 may be provided with one or a plurality of return suppressing recesses. Similar changes can be made with respect to the return restraint recess 140 of the embodiment of FIG. 9A.

In each embodiment, plugs (plugs) that are screwed into the inlets of the holding holes 16 are used as the blocking members 19 and 119. Instead, the cylinders that define the inlets of the holding holes 16 in the housing 17 are used. A cap having a female protrusion on the inner periphery which is provided with a cylindrical protrusion and engages with a male thread on the outer periphery of the cylindrical protrusion may be used.
Further, in each embodiment, as the rotational force biasing springs 22 and 122, a mainspring spring (not shown) may be used instead of the torsion coil spring to reduce the size in the depth direction X1. Further, a rod-like torsion bar may be used as the rotational force biasing spring 22.

In each embodiment, the urging member 27 may be a block-like elastic member such as an O-ring, a rubber plate, or a rubber bar.
Although not shown, in the embodiment of FIG. 3, the urging member 27 may be interposed between the front surface 21 a of the second intermediate member 21 and the rear surface 18 b of the support yoke 18. Although not shown, in the embodiment of FIG. 8, the urging member 27 may be interposed between the front surface 120 a of the first intermediate member 120 and the low friction plate 128, or the urging member 27. May be interposed between the rear surface 18 b of the support yoke 18 and the low friction plate 128.

  In addition, various modifications can be made within the scope of the claims of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Steering device, 2 ... Steering member, 7 ... Pinion shaft, 8 ... Rack shaft, 15; 115 ... Rack shaft support device, 16 ... Holding hole, 17 ... Housing, 18 ... Support yoke (rack shaft support member), 19 119: Closing member, 20; 120: First intermediate member, 20a; 120a ... Front surface, 20b, 120b ... Rear surface, 21; 121 ... Second intermediate member, 21a; 121a ... Front surface, 21b; 121b ... Rear surface, 22; 122: rotational force biasing spring, 23; 123 ... cam surface, 24; 124 ... cam surface, 25; 125 ... rolling element, 26; 126 ... cam mechanism, 27 ... biasing member, 33 ... engagement groove, 34 ... Guide pin, 36, 37; 136, 137 ... holding groove, 38 ... retainer, 39 ... holding hole, 40; 41; 42; 140 ... return restraining recess, C1 ... (holding hole) central axis, L1 ... (support) Yaw L2 ... (the length of both intermediate members), L3 ... set length (of the biasing member), R ... rotational force, X1 ... depth direction (of the holding hole), Y1 ... circumferential direction, Z1 ... axial direction (of rack axis)

Claims (5)

A rack shaft support member that is slidably accommodated in the holding hole of the housing in the depth direction of the holding hole and slidably supports the rack shaft;
A closing member that is fixed to the housing and closes the holding hole;
An urging member interposed between the rack shaft support member and the closing member and elastically urging the rack shaft support member toward the rack shaft;
A first intermediate member that is interposed between the rack shaft support member and the closing member, and is rotatable around a central axis of the holding hole;
A rotational force biasing spring that engages one of the closing member and the second intermediate member and the first intermediate member, and applies a rotational force to the first intermediate member;
A cam surface provided on at least one of the opposing surfaces of both intermediate members and inclined with respect to the rotation direction of the first intermediate member; and a rolling element engaged with the cam surface between the opposing surfaces of both intermediate members; A cam mechanism that increases the total length of both intermediate members in the depth direction with relative rotation of both intermediate members by the rotational force biasing spring ;
A rack shaft support device, wherein the cam surface is provided with a return restraining recess that holds the rolling element with a predetermined holding force and suppresses the return of the rolling element along an inclination direction of the cam surface . The rack shaft support device according to claim 1 , wherein a plurality of the return suppression recesses are provided apart from each other in an inclination direction of the cam surface. 3. The biasing member according to claim 1, wherein the biasing member is interposed between the intermediate member facing the closing member and the closing member among the two intermediate members, and the rack shaft support member is interposed between the intermediate members. A rack shaft support device that elastically biases the rack shaft side. In any one of claims 1 to 3, wherein the first intermediate member is arranged to face the rack shaft support member,
A rack shaft support device comprising a low friction plate interposed between opposed surfaces of the rack shaft support member and the first intermediate member, or a low friction portion provided on at least one of the opposed surfaces. A steering device that supports the rack shaft so as to be slidable in the axial direction using the rack shaft support device according to any one of claims 1 to 4 .

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