JP2013159293A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device capable of much more absorbing impact due to end hitting.SOLUTION: A steering device includes: a rack shaft 5 which is provided so as to reciprocate axially in a rack housing; a rack end which has a socket 32 threaded into the shaft end of the rack shaft 5, and which freely and turnably connects a tie rod with the socket 32. The steering device is provided within the rack housing. By means of a spacer 50 formed from an elastic body provided between the end surface 39a of the rack end and a regulatory surface 38 abutting on the end surface 39a of the rack end for regulating the movement of the rack end, the impact due to collision between the regulatory surface 38 and the end surface 39a is absorbed. The spacer 50 includes: an uneven part 51 which shrinks in the axial direction of the rack shaft 5; and a radial deformation part which shrinks in the axial direction of the rack shaft 5 and bulges in the radial direction of the rack shaft 5, when the regulatory surface 38 abuts against the end surface 39a.

Description

  The present invention relates to a steering device.

  Conventionally, in a steering apparatus for a vehicle, the steering angle of a steered wheel is changed by transmitting rotation of a steering shaft accompanying steering of a steering hole to a steering mechanism such as a rack and pinion mechanism.

  A rack end that rotatably connects the tie rod to the rack shaft is provided at the shaft end of the rack shaft that constitutes such a rack and pinion mechanism. The rack end is constituted by, for example, a ball joint, and is fixed to the rack shaft by screwing a socket of the ball joint to the shaft end portion of the rack shaft (see, for example, Patent Document 1).

  In the steering device having the rack and pinion mechanism as described above, the rack end abuts against the rack housing that houses the rack shaft, and the movement of the rack shaft is mechanically restricted, so that the movable range of the rack shaft, that is, The movable range of the steered wheels is determined. For this reason, if the steering wheel is operated at a high steering angular speed in a state where the steering wheel is operated near the maximum allowable steering angle, that is, in a state where the steered wheel is rotated to the vicinity of its movable limit, An impact is applied to the steering system by so-called end contact that collides with the steering wheel. Therefore, an impact absorbing member made of an elastic body is installed between the regulating surface of the rack housing and the end surface of the rack end to absorb the impact at the time of contact.

JP 2006-1510 A

  Incidentally, rotation of the steering shaft is assisted by hydraulic power steering, but in recent years, rotation of the steering shaft is assisted by electric power steering (EPS). In a steering apparatus equipped with EPS, a large driving force is instantaneously generated, so that the inertia is larger than that of a hydraulic type, and it is necessary to improve the strength of each member in order to absorb a larger impact. However, increasing the strength of each member increases the size and weight of each member, which leads to a deterioration in fuel consumption of the vehicle. Therefore, it is required to absorb a larger impact while using existing members. It was. For this reason, in a steering apparatus provided with EPS, a steering apparatus that can absorb the impact caused by end contact more than before has been demanded. There is a similar demand not only for a steering device equipped with EPS but also for a steering device equipped with a high output hydraulic power steering.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a steering device that can absorb an impact caused by an end contact more than ever.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 includes a rack shaft provided in a rack housing so as to be capable of reciprocating in an axial direction, and a socket screwed to an end portion of the rack shaft, and a tie rod with respect to the socket. A rack end that is rotatably connected to the rack housing, and a regulation surface that abuts against an end surface of the rack end to regulate movement of the rack end, and an end surface of the rack end. In a steering device that absorbs an impact caused by the contact between the restriction surface and the end surface by an impact absorption member made of an elastic body provided in between, the shock absorption member is sandwiched between the restriction surface and the end surface In this case, an axial deformation portion that reduces in the axial direction of the rack shaft and a radial deformation portion that reduces in the axial direction of the rack shaft and expands in the radial direction of the rack shaft are provided. Are you as its gist.

  According to this configuration, when so-called end contact occurs where the rack end collides with the rack housing, if the rack shaft is displaced and the distance between the end surface of the rack end and the regulating surface of the rack housing is narrowed, the shock absorbing member is It is sandwiched between the regulation surface of the rack housing and the end surface of the rack end. At this time, the axially deformed portion of the shock absorbing member is reduced in the axial direction of the rack shaft to absorb the impact caused by the rack end contacting, and the radially deformable portion of the shock absorbing member is further reduced in the axial direction. While expanding in the radial direction, the shock due to the contact of the rack end is absorbed. For this reason, conventionally, only the impact absorption by the radially deformable portion is performed, but the impact absorption by the axially deformable portion is added, so that the impact due to the end contact can be absorbed more than before. Therefore, in a steering device equipped with EPS or a steering device equipped with high output hydraulic power steering, it is possible to absorb an impact caused by end contact while using an existing member.

  The gist of the invention according to claim 2 is that, in the steering device according to claim 1, the axially deforming portion is an uneven portion having a different thickness in the axial direction of the rack shaft.

  According to this configuration, the axially deformed portion is an uneven portion having a different thickness in the axial direction of the rack shaft. For this reason, when the surface in the axial direction of the shock absorbing member is sandwiched between the restriction surface of the rack housing and the end surface of the rack end, the convex portion is crushed and deformed so as to move into the space corresponding to the concave portion. The impact due to the contact of the end can be absorbed more than before.

The gist of the invention according to claim 3 is that, in the steering device according to claim 2, the axially deforming portion is provided on both end faces in the axial direction of the rack shaft.
According to this configuration, since the axially deformed portions are formed on both end surfaces in the axial direction of the rack shaft of the shock absorbing member, the rack end is in contact with when the axially deformed portion is provided only on one side. The shock due to can be further absorbed.

  According to a fourth aspect of the present invention, in the steering device according to any one of the first to third aspects, an end surface side of the rack end opens in the axial direction of the rack shaft on the regulation surface of the rack housing. And the impact absorbing member is provided between the bottom surface of the recessed portion in the axial direction of the rack shaft and the end surface of the rack end, and the impact absorbing member in the axial direction of the rack shaft is provided. The gist of the invention is that the thickness is greater than the depth of the recess and is set to have the same thickness as the depth of the recess when the shock absorbing member is sandwiched between the bottom surface and the end surface of the recess to reduce the thickness. It is said.

  According to the same configuration, the thickness of the shock absorbing member is set to the same thickness as the depth of the recess after the shock absorbing member is reduced at the time of end contact, that is, the thickness at which the regulation surface of the rack housing and the end surface of the rack end abut. did. For this reason, when the shock absorbing member absorbs the shock caused by the rack end coming into contact with the end hit and the steered wheel is rotated to the movable limit and the shock absorbing member is compressed, the restriction surface of the rack housing The end position can be fixed by restricting the movement of the rack end by contacting the end surface of the rack end.

  According to a fifth aspect of the present invention, in the steering apparatus according to the fourth aspect, the outer diameter of the shock absorbing member in the radial direction of the rack shaft is such that the shock absorbing member is sandwiched between the bottom surface and the end surface of the recess. Even if it expands in the radial direction of the rack shaft, the gist is that it is set shorter than the inner diameter of the side wall of the recess.

  According to this configuration, even if the outer diameter of the shock absorbing member expands in the radial direction of the rack shaft due to the rack end coming into contact when the end contact occurs, the shock absorbing member remains on the side wall of the recess in the radial direction of the rack shaft. Do not touch. For this reason, the part expanded in the radial direction of the shock absorbing member is not sandwiched between the restricting surface of the rack housing and the end surface of the rack end, and the deterioration of the shock absorbing member can be suppressed.

  According to a sixth aspect of the present invention, in the steering apparatus according to the fourth or fifth aspect, the inner diameter of the shock absorbing member in the radial direction of the rack shaft is such that the shock absorbing member is located between the bottom surface of the recess and the end surface. The gist of the invention is that it is set longer than the outer diameter of the outer peripheral surface of the rack shaft even if it is sandwiched and reduced in the radial direction of the rack shaft.

  According to this configuration, even if the inner diameter of the shock absorbing member is reduced in the radial direction of the rack shaft due to the rack end contacting when the end contact occurs, the shock absorbing member is Do not touch the outer surface. For this reason, the part expanded in the radial direction of the shock absorbing member does not contact the outer peripheral surface of the rack shaft, and deterioration of the shock absorbing member can be suppressed.

  According to the present invention, it is possible to absorb the impact caused by the end contact more than before.

The schematic block diagram of a steering device. The longitudinal cross-sectional view which shows the structure of the steering device of a non-end contact state. The longitudinal cross-sectional view which shows the structure of the steering device of an end contact state. The perspective view which shows the shape of a spacer. The enlarged view which shows the deformation | transformation of the spacer of the steering device at the time of non-end contact. The enlarged view which shows a deformation | transformation of the spacer of the steering device of an end contact initial stage. The enlarged view which shows the deformation | transformation of the spacer of the steering device at the time of end contact. The figure which shows the relationship between the displacement amount of a spacer, and contact time. The perspective view which shows the shape of a spacer.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, in a steering device including an electric power steering (EPS) 1, a steering shaft 3 to which a steering wheel 2 is fixed is connected to a rack shaft 5 via a rack and pinion mechanism 4. . The rack shaft 5 is inserted into a cylinder of a substantially cylindrical rack housing 6 and supported so as to be capable of reciprocating in the axial direction via a rack bush (not shown). Thereby, the rotation of the steering shaft 3 accompanying the operation of the steering wheel 2 is converted into a reciprocating linear motion of the rack shaft 5 by the rack and pinion mechanism 4. The steering shaft 3 is configured by connecting a column shaft 8, an intermediate shaft 9, and a pinion shaft 10.

  A tie rod 13 is rotatably connected to both ends of the rack shaft 5 via a rack end 12 provided at the shaft end portion 11 thereof. The tip of the tie rod 13 is connected to a knuckle (not shown) to which the steered wheel 14 is assembled. The reciprocating linear motion of the rack shaft 5 accompanying the rotation of the steering shaft 3 is transmitted to the knuckle through the tie rods 13 connected to both ends of the rack shaft 5, so that the steering angle of the steered wheels 14, that is, The traveling direction of the vehicle is changed.

  The EPS 1 also includes an EPS actuator 22 that applies an assist force for assisting the operation of the steering wheel 2 to the steering system using the motor 21 as a drive source, and an ECU 23 that controls the operation of the EPS actuator 22.

  The EPS actuator 22 is configured as a so-called column assist type EPS actuator, and a motor 21 as a driving source thereof is drivingly connected to the column shaft 8 via a speed reduction mechanism 25. The speed reduction mechanism 25 is configured by meshing a wheel gear 26 connected to the column shaft 8 and a worm gear 27 connected to the motor 21. The rotation of the motor 21 is decelerated by the deceleration mechanism 25 and transmitted to the column shaft 8 so that the motor torque is applied to the steering system as an assist force.

  On the other hand, a vehicle speed sensor 28 and a torque sensor 29 are connected to the ECU 23. The ECU 23 is configured to execute the operation of the EPS actuator 22, that is, control of the assist force applied to the steering system, based on the vehicle speed V and the steering torque τ detected by these sensors.

Next, the structure of the rack end 12 in the EPS 1 of the present embodiment will be described.
As shown in FIGS. 2 and 3, the rack end 12 includes a ball stud 31 having a ball portion 31 a at the tip, and a substantially bottomed cylindrical socket 32 that rotatably accommodates the ball portion 31 a. It is configured as a ball joint with. Inside the socket 32, a resin sheet 32a on which a spherical spherical seat corresponding to the ball portion 31a of the ball stud 31 is formed is mounted. The ball stud 31 is pivotally connected to the socket 32 by fitting the ball portion 31a to the resin sheet 32a. Note that, by fixing one end of the tie rod 13 to the ball stud 31, the tie rod 13 is rotatably connected to the rack shaft 5.

  The rack end 12 is fixed to the rack shaft 5 by the socket 32 being screwed to the shaft end portion 11 of the rack shaft 5. Specifically, a screw shaft 35 that protrudes toward the rack shaft 5 is formed at the bottom 34 of the socket 32. On the other hand, the rack shaft 5 is formed in a hollow shape. A screw portion 36 corresponding to the screw shaft 35 is formed on the inner peripheral surface of the shaft end portion 11. The rack end 12 is fixed to the shaft end portion 11 of the rack shaft 5 by screwing the screw shaft 35 into the screw portion 36. A claw washer 39 for restricting relative rotation between the rack shaft 5 and the rack end 12 is provided between the shaft end portion 11 and the socket 32. The claw washer 39 prevents the tightening of the screw shaft 35 with respect to the screw portion 36 from being loosened due to, for example, vibration generated as the vehicle travels.

  The outer diameter of the socket 32 is formed to be larger than the outer diameter of the rack shaft 5, and the bottom 34 in the axial direction of the socket 32 on the rack shaft 5 side reciprocates the rack shaft 5. It is configured to be able to come into contact with a regulating surface 38 formed inside. That is, inside the both ends of the rack housing 6, there are an insertion portion 6a through which the rack shaft 5 is inserted, an enlarged diameter portion 6b in which the diameter is larger than that of the insertion portion 6a and the socket 32 is inserted, and the insertion portion 6a and the enlarged diameter. A step portion 6c serving as a boundary with the portion 6b is formed. A metal annular stopper 40 is fitted to the stepped portion 6 c, and the end surface of the stopper 40 on the socket 32 side functions as a regulating surface 38. Therefore, the movement of the rack end 12 is regulated by the stopper 40 and the claw washer 39 coming into contact with each other. The rack shaft 5 is inserted through the stopper 40 without contact. An annular recess 41 is formed at the inner end of the stopper 40 on the rack shaft 5 side of the regulating surface 38.

  Between the regulating surface 38 of the stopper 40 and the end surface 39a of the claw washer 39, a spacer 50 is provided as an impact absorbing member that absorbs an impact when the rack end 12 contacts the stopper 40. The spacer 50 is made of an elastic body and is attached to the end face 39 a of the claw washer 39. When the rack end 12 abuts against the stopper 40, each end surface of the spacer 50 in the axial direction of the rack shaft 5 abuts against the claw washer 39 and the bottom surface 41 a of the recess 41, while the spacer 50 is in the recess 41 of the stopper 40. Located in.

  As shown in FIG. 4, uneven portions 51 having different thicknesses in the axial direction of the rack shaft 5 are integrally formed on both end surfaces of the spacer 50 of this embodiment. The concavo-convex portion 51 is formed in a circular shape along the circumferential direction of the spacer 50, and a plurality of ridge portions 53 protruding from the end face of the spacer by a predetermined amount, and between the ridge portions 53 and the ridge portions 53 protrude. The groove portion 52 has a substantially zero amount. Therefore, the concavo-convex portion 51 is formed by alternately arranging the groove portions 52 and the protrusions 53 in the radial direction of the rack shaft 5. The uneven portion 51 functions as an axially deforming portion. The portions other than the concavo-convex portion 51 of the spacer 50 constitute a radial deformation portion 54 that contracts in the axial direction of the rack shaft 5 and expands in the radial direction of the rack shaft 5.

  Next, the operation of the steering apparatus configured as described above will be described with reference to FIGS. Here, the inner diameter (radius) of the side wall 41b of the recess 41 of the stopper 40 is R1, the outer diameter (radius) of the rack shaft 5 is R2, and the length between the outer peripheral surface of the rack shaft 5 and the side wall 41b of the recess 41 is L1. = R1-R2.

  As shown in FIG. 5, in an unsteered state, an end surface 39 a of a claw washer 39 provided on the bottom 34 of the rack end 12 and a stopper 40 attached to a stepped portion 6 c formed in the rack housing 6. This is apart from the regulation surface 38. The spacer 50 is fitted to the rack shaft 5 in a state where it does not deform in contact with the end face 39a of the claw washer 39. At this time, the outer diameter R3 of the spacer 50 is shorter than the inner diameter R1 of the side wall 41b of the recess 41, and the inner diameter R4 of the spacer 50 is longer than the outer diameter R2 of the rack shaft 5. That is, the radial width W1 (W1 = R3-R4) of the spacer 50 is shorter than the length L1 (L1 = R1-R2) between the side wall 41b of the recess 41 of the stopper 40 and the outer peripheral surface of the rack shaft 5 ( W1 <L1). The thickness D1 of the spacer 50 is longer than the depth L2 of the recess 41 of the stopper 40 (D1> L2).

  As shown in FIG. 6, when the rack shaft 5 reaches the limit of the movable range by being steered, the end surface 39 a of the claw washer 39 and the regulating surface 38 of the stopper 40 are closer than the state of FIG. 5. Is away. The spacer 50 is pressed by both the end surface 39 a of the crow washer 39 and the restriction surface 38 of the stopper 40 and is compressed in the axial direction of the rack shaft 5. The uneven portion 51 of the spacer 50 is deformed so that the protrusion 53 is crushed and moved to the groove 52. At this time, the outer diameter R5 of the spacer 50 is shorter than the inner diameter R1 of the side wall 41b of the recess 41, and the inner diameter R6 of the spacer 50 is longer than the outer diameter R2 of the rack shaft 5. That is, the radial width W2 (W2 = R5-R6) of the spacer 50 is the same as the width W1 in the unsteered state, and is the length between the side wall 41b of the recess 41 of the stopper 40 and the outer peripheral surface of the rack shaft 5. Shorter than L1 (W2 = W1 <L1). Further, since the thickness D2 of the spacer 50 is compressed in the axial direction of the rack shaft 5, it is shorter than the thickness D1 when the steering is not performed, but is longer than the depth L2 of the concave portion 41 of the stopper 40 (D1). > D2> L2).

  As shown in FIG. 7, when the rack shaft 5 reaches the limit of the movable range by being steered, the end surface 39 a of the crow washer 39 and the regulating surface 38 of the stopper 40 abut. The spacer 50 is pressed by both the end surface 39 a of the crow washer 39 and the restriction surface 38 of the stopper 40 and is compressed in the axial direction of the rack shaft 5. In addition to the compressive deformation of the concave and convex portion 51 in the axial direction of the rack shaft 5, the spacer 50 is deformed in the radial direction of the rack shaft 5 while the radial deformable portion 54 is compressed and deformed in the radial direction of the rack shaft 5. . At this time, the outer diameter R7 of the spacer 50 is shorter than the inner diameter R1 of the side wall 41b of the recess 41, and the inner diameter R8 of the spacer 50 is longer than the outer diameter R2 of the rack shaft 5. That is, the radial width W3 (W3 = R7−R8) of the spacer 50 is longer than the width W2 in the state of reaching the limit, and is the length between the side wall 41b of the recess 41 of the stopper 40 and the outer peripheral surface of the rack shaft 5. Shorter than the length L1 (W2 <W3 <L1). Here, since the outer surface of the spacer 50 does not contact the side wall 41b of the concave portion 41, the spacer 50 is not sandwiched between the end surface 39a of the claw washer 39 and the regulating surface 38 of the stopper 40, so that the end portion is deteriorated. Absent. Further, since the thickness D3 of the spacer 50 is compressed in the axial direction of the rack shaft 5, it is shorter than the thickness D2 in the state of reaching the limit and is the same as the depth L2 of the recess 41 of the stopper 40 ( D3 = L2 <D2).

  When the steering is performed in the reverse direction, the end surface 39a of the rack end 12 is separated from the regulating surface 38 in the rack housing 6, and the spacer 50 is contracted in the radial direction of the rack shaft 5 and expanded in the axial direction. 6 and then returns to the original shape shown in FIG.

  As shown in FIG. 8, in the spacer 50 of this embodiment, compared with the conventional shock absorbing member, the time for shock absorption becomes longer due to a large displacement with respect to the shock, and the shock is absorbed more than before. Yes. The displacement here is the sum of the displacement amounts of both the axial direction and the radial direction of the rack shaft 5. More specifically, in the present embodiment shown by a solid line, when the end contact occurs, the time when the end surface 39a of the rack end 12 abuts against the spacer 50 is set to 0, and at the initial stage (until time T1), the spacer 50 The impact is absorbed by the uneven portion 51 being reduced in the axial direction (displacement amount Ya). Further, the radial deformation portion 54 of the spacer 50 absorbs the impact by expanding in the radial direction while reducing in the axial direction from time Ta to time T2 (displacement amount Y1 = Y2−Ya). On the other hand, in the prior art indicated by the one-dot chain line, the impact is absorbed by expanding in the radial direction (displacement amount Y1) while shortening in the axial direction from time 0 to time T1. That is, the spacer 50 according to the present embodiment is more deformed by the deformation (displacement amount Ya) due to the uneven portion 51 than the conventional one, and can absorb the impact more than the conventional one. Therefore, when the rack shaft 5 is moved to the limit of the movable range by steering and the end face 39a of the rack end 12 abuts against the regulating surface 38 of the rack housing 6, the spacer 50 is deformed while using an existing member. Can absorb shocks.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) When so-called end contact occurs in which the rack end 12 collides with the rack housing 6, the rack shaft 5 is displaced, and the distance between the end surface 39 a of the rack end 12 and the regulating surface 38 of the rack housing 6 is reduced. The spacer 50 is sandwiched between the regulation surface 38 of the rack housing 6 and the end surface 39a of the rack end 12. At this time, the concave and convex portion 51 of the spacer 50 is reduced in the axial direction of the rack shaft 5 to absorb the impact caused by the contact of the rack end 12, and the radial deformation portion 54 of the spacer 50 is reduced in the axial direction. However, by expanding in the radial direction, the impact due to the contact of the rack end 12 is absorbed. For this reason, conventionally, only the shock absorption by the radially deformable portion was performed, but the shock absorption by the uneven portion 51 was added, so that the impact by the end contact can be absorbed more than before. Therefore, in the steering device provided with the EPS 1, it is possible to absorb an impact caused by the end contact while using an existing member.

  (2) The axially deformed portion is an uneven portion 51 having a different thickness in the axial direction of the rack shaft 5. Therefore, when the axial surface of the spacer 50 is sandwiched between the regulating surface 38 of the rack housing 6 and the end surface 39a of the rack end 12, the protrusion 53 is crushed and deformed so as to move to the space of the groove 52. By doing so, it is possible to absorb the impact caused by the contact of the rack end 12 more than before.

  (3) Since the concavo-convex portions 51 are formed on both end surfaces in the axial direction of the rack shaft 5 of the spacer 50, the impact caused by the contact of the rack end 12 is further increased as compared with the case where the concavo-convex portions 51 are provided only on one side. Can absorb.

  (4) The thickness of the spacer 50 is set to the same thickness as the depth of the recess 41 after the spacer 50 is contracted when the end is applied, that is, the thickness where the regulating surface 38 of the rack housing 6 and the end surface 39a of the rack end 12 abut. did. For this reason, when the spacer 50 absorbs an impact caused by the rack end 12 contacting when the end contact occurs, and the steered wheel is rotated to the movable limit and the spacer 50 is compressed, the regulating surface 38 of the rack housing 6 is compressed. And the end surface 39a of the rack end 12 abut, the movement of the rack end 12 can be restricted and the end position can be fixed.

  (5) Even if the outer diameter of the spacer 50 expands in the radial direction of the rack shaft 5 by the rack end 12 coming into contact when the end contact occurs, the spacer 50 remains on the side wall 41 b of the recess 41 in the radial direction of the rack shaft 5. And no contact with the outer peripheral surface of the rack shaft 5. For this reason, the radially enlarged portion of the spacer 50 is not sandwiched between the regulating surface 38 of the rack housing 6 and the end surface 39a of the rack end 12, and the deterioration of the spacer 50 can be suppressed.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, the outer diameter surface of the spacer 50 is prevented from coming into contact with the inner wall surface of the recess 41. However, when the end surface 39a of the claw washer 39 and the regulating surface 38 of the stopper 40 abut, If it does not pop out, it may contact the inner wall surface of the recess 41.

  In the above-described embodiment, the side wall 41b of the recess 41 and the rack shaft 5 side are opened, but the opening may be formed only on the end surface side without opening on the rack shaft 5 side. The recess 41 is sized so that the spacer 50 can be accommodated when the end surface 39a of the crow washer 39 and the regulating surface 38 of the stopper 40 come into contact with each other.

  In the above embodiment, the concave and convex portions 51 are formed on both end surfaces of the spacer 50 in the axial direction of the rack shaft 5. However, if the impact at the time of end contact can be absorbed, the spacer 50 in the axial direction of the rack shaft 5. The uneven portion 51 may be formed only on one side.

  In the above embodiment, the concave and convex portions 51 in which the groove portions 52 and the ridge portions 53 are alternately arranged in the radial direction of the rack shaft 5 are used. However, when the spacer 50 is first crushed as the axially deformed portion, Other shapes may be used as long as the impact can be absorbed by reducing the axial direction. For example, as shown in FIG. 9, the end face in the axial direction of the rack shaft 5 of the spacer 50 may have a shape in which a large number of convex portions 55 protrude in the axial direction of the rack shaft 5. Further, the end face of the spacer 50 in the axial direction of the rack shaft 5 may be formed in a wave shape.

  In the above embodiment, the claw washer 39 is provided between the rack shaft 5 and the socket 32. However, if the relative rotation between the rack shaft 5 and the socket 32 of the rack end 12 can be restricted, the claw washer 39 may be omitted. Good.

  In the above embodiment, the stopper 40 is provided with the recess 41 in which the spacer 50 is accommodated when the end surface 39a of the rack end 12 and the regulating surface 38 in the rack housing 6 come into contact with each other. However, if there is a space in the axial direction of the rack shaft 5, the recess 41 may not be formed, and the spacer 50 may be directly sandwiched between the end surface 39 a of the rack end 12 and the regulating surface 38 in the rack housing 6.

  In the above embodiment, the stopper 40 is provided in the rack housing 6. However, if the rack housing 6 itself can absorb an impact caused by the rack end 12 coming into contact with the rack housing 6, the stopper 40 is omitted and the rack 40 is omitted. The end surface of the rack end 12 may be brought into contact with the step portion 6 c in the housing 6.

In the above embodiment, the rack end 12 is configured to use a ball joint, but may be configured to use other joints for the rack end.
In the above embodiment, the present invention is embodied in a steering apparatus configured as a column assist type electric power steering apparatus (EPS). However, the present invention is not limited to this, and the present invention may be applied to an EPS other than column assist, such as a so-called rack assist type, or a hydraulic power steering device.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering (EPS), 4 ... Rack and pinion mechanism, 5 ... Rack shaft, 6 ... Rack housing, 11 ... Shaft end, 12 ... Rack end, 13 ... Tie rod, 31 ... Ball stud, 32 ... Socket, 34 ... Bottom part, 35 ... Screw shaft, 36 ... Screw part, 38 ... Restricting surface, 39 ... Claw washer, 39a ... End face, 40 ... Stopper, 41 ... Recess, 41a ... Bottom surface, 41b ... Side wall, 50 ... As an impact absorbing member , 51 ... Uneven portion as axially deforming portion, 52 ... Groove portion, 53 ... Projection portion, 54 ... Radially deforming portion, D1, D2, D3 ... Thickness of spacer, L1 ... Outer circumferential surface of rack shaft Length of recess with side wall, L2 ... Depth of recess, R1 ... Inner diameter of recess, R2 ... Outer diameter of rack shaft, R3 ... Outer diameter of spacer, R4 ... Inner diameter of spacer, W1, W2, W3 ... width

Claims (6)

A rack shaft provided in the rack housing so as to be capable of reciprocating in the axial direction;
A rack end having a socket screwed to the shaft end portion of the rack shaft, and a tie rod rotatably connected to the socket;
A shock absorbing member made of an elastic body provided between the end surface of the rack end and a restricting surface that is provided in the rack housing and contacts the end surface of the rack end to restrict the movement of the rack end. In a steering device that absorbs an impact caused by contact between the regulation surface and the end surface,
The shock absorbing member has an axially deforming portion that contracts in the axial direction of the rack shaft when the regulation surface and the end surface abut, a contraction in the axial direction of the rack shaft, and a diameter of the rack shaft. A steering device comprising: a radially deforming portion that expands in a direction. The steering apparatus according to claim 1, wherein
The steering device according to claim 1, wherein the axially deforming portion is an uneven portion having a different thickness in the axial direction of the rack shaft. The steering apparatus according to claim 2, wherein
The steering device according to claim 1, wherein the axially deforming portion is provided on both end surfaces in the axial direction of the rack shaft. In the steering device according to any one of claims 1 to 3,
On the regulation surface of the rack housing, a recess is formed in which the end surface side of the rack end is opened and recessed in the axial direction of the rack shaft.
The shock absorbing member is provided between a bottom surface of the recess in the axial direction of the rack shaft and an end surface of the rack end;
The thickness of the shock absorbing member in the axial direction of the rack shaft is thicker than the depth of the recess, and when the shock absorbing member is sandwiched between the bottom surface and the end surface of the recess, the thickness is the same as the depth of the recess. A steering device characterized by being set to be The steering apparatus according to claim 4, wherein
The outer diameter of the shock absorbing member in the radial direction of the rack shaft is equal to the inner diameter of the side wall of the concave portion even when the shock absorbing member is sandwiched between the bottom surface and the end surface of the concave portion and expands in the radial direction of the rack shaft. Steering device characterized by being set shorter than the above. The steering apparatus according to claim 4 or 5,
The inner diameter of the shock absorbing member in the radial direction of the rack shaft is equal to the outer peripheral surface of the rack shaft even if the shock absorbing member is sandwiched between the bottom surface and the end surface of the recess and is reduced in the radial direction of the rack shaft. Steering device characterized in that it is set longer than the outer diameter.

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