Vehicle steering device

Abstract

A stopper mechanism part in this vehicle steering device is provided with: a rotary member that has a connection part which is connected to a steering shaft, and a cylindrical part which is positioned on one side in the axial direction relative to said connection part and which has a female thread in the inner circumference thereof; a linear motion member that moves linearly in the axial direction relative to the rotary member; a first housing that is positioned on the outer circumferential side of the cylindrical part and the linear motion member; and a second housing that is positioned on the other side in the axial direction relative to the first housing and on the outer circumferential side of the connection part, and that is attached to the first housing.

Description

Vehicle steering device

[0001] The present disclosure relates to a vehicle steering system.

[0002] In a steer-by-wire vehicle steering system, the steering shaft connected to the steering wheel is mechanically disconnected from the steered wheels. In this configuration, the steering reaction force is not transmitted to the steering wheel, so a steering reaction force device and a stopper mechanism are provided on the steering shaft.

[0003] The steering reaction force device applies a reaction force to the steering wheel in the opposite direction to the rotational direction (steering direction) of the steering wheel, giving the driver a natural steering feel. The steering reaction force device includes, for example, a motor and a speed reduction mechanism, and the steering reaction force generated by the motor is transmitted to the steering shaft via the speed reduction mechanism. The speed reduction mechanism includes, for example, a worm shaft and a worm wheel, and the rotation of the motor is transmitted to the worm wheel via the worm shaft as the shaft teeth of the worm shaft mesh with the wheel teeth of the worm wheel.

[0004] The stopper mechanism includes, for example, a cylindrical rotating member that fits onto the outer periphery of the steering shaft, a nut that is fastened to the outer periphery of the rotating member and moves linearly in the axial direction relative to the rotating member, a first stopper portion that fits onto one axial side of the rotating member to stop the linear movement of the nut, a second stopper portion that fits onto the other axial side of the rotating member to stop the linear movement of the nut, and a first housing and a second housing that accommodate the rotating member, the nut, the first stopper portion, and the second stopper portion. The outer periphery of the rotating member is provided with a male thread, and the inner periphery of the nut is provided with a female thread that meshes with the male thread. When the nut abuts against the first stopper portion or the second stopper portion, rotation of the rotating member is stopped, and therefore rotation (steering) of the steering wheel via the steering shaft is also stopped.

[0005] German Patent No. 102020126785

[0006] However, in Patent Document 1, the assembly work of the stopper mechanism is complicated and may result in a large workload. Specifically, first, the first housing is attached to the outer periphery of the steering shaft. Next, a stopper unit including a rotating member, a nut, a first stopper portion, and a second stopper portion is assembled. Specifically, the first stopper portion is fitted to one axial side of the rotating member, and the nut is fastened to the outer periphery of the rotating member. Then, the second stopper portion is fitted to the other axial side of the rotating member to form the stopper unit. The stopper unit is inserted (spline-fitted) toward one axial side of the steering shaft and abutted against the first housing. Then, the second housing is fitted from one axial side of the steering shaft to complete the assembly work of the stopper mechanism.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a vehicle steering device including a stopper mechanism that can be assembled more easily.

[0008] In order to achieve the above object, one embodiment of a vehicle steering device is a vehicle steering device in which a steering shaft to which a steering wheel is connected is mechanically disconnected from steered wheels, and the vehicle steering device is provided with a stopper mechanism that restricts the range of rotation angle of the steering wheel when the steering wheel is rotated, and the stopper mechanism is a rotating member that extends in the axial direction of a central axis and is rotatable in the circumferential direction around the central axis, the rotating member having a connecting portion that is connected to the steering shaft and a tubular portion that is located on one side of the connecting portion in the axial direction and has a female thread on its inner circumference; The linear motion member is provided on the inner periphery of the cylindrical portion and has a male thread on its outer periphery that engages with the female thread, and moves linearly in the axial direction relative to the rotating member; a first housing is located on the outer periphery of the cylindrical portion and the linear motion member and holds the linear motion member in a state in which it cannot rotate in the circumferential direction but can move linearly in the axial direction; a second housing is located on the other axial side of the first housing and on the outer periphery of the connecting portion and is attached to the first housing; and first and second abutment portions with which the linear motion member abuts, stopping its linear motion.

[0009] As mentioned above, in Patent Document 1, the assembly work of the stopper mechanism is complicated and may result in a large workload. Specifically, the first housing is attached to the outer periphery of the steering shaft. Next, a stopper unit having a rotating member, a nut, a first stopper portion, and a second stopper portion is assembled. The stopper unit is inserted (spline-fitted) toward one side of the steering shaft in the axial direction and abutted against the first housing, and then the second housing is fitted from one side of the steering shaft in the axial direction, thereby completing the assembly work of the stopper mechanism.

[0010] In contrast, according to the present disclosure, the stopper mechanism can be assembled using the following simple procedure. Specifically, first, the male thread of the linear moving member is fastened to the female thread of the rotating member from one side to the other in the axial direction, thereby assembling the linear moving member to the rotating member from one side to the other in the axial direction. Next, the first housing is inserted from one side to the other in the axial direction around the outer periphery of the rotating member and the linear moving member, and the second housing is attached to the first housing. In this way, according to the present disclosure, it is possible to provide a vehicle steering device including a stopper mechanism that is easier to assemble.

[0011] In a preferred aspect, a female spline is provided on the inner periphery of the first housing, and the linear motion member has a male threaded portion having the male thread and capable of abutting against the first abutment portion and the second abutment portion, and a spline portion located on one axial side of the male threaded portion and having a male spline on its outer periphery that can fit into the female spline, and a through hole penetrating in the axial direction is provided at one axial end of the first housing, and when the linear motion member moves linearly toward one axial side, the spline portion of the linear motion member can protrude from the through hole of the first housing to one axial side.

[0012] When the steering wheel is turned, the steering shaft and the rotating member rotate, and the linear moving member moves in the axial direction. However, if the linear moving member is housed inside the housing and cannot be seen from the outside, it is difficult to determine the axial position of the linear moving member, and therefore it is difficult to determine the direction of rotation of the steering wheel (clockwise or counterclockwise) and the rotation angle.

[0013] In contrast, in the present disclosure, the spline portion of the linear motion member can protrude from the through hole to one side in the axial direction, making it possible to visually confirm the rotation direction and rotation angle of the steering wheel. Therefore, the rotation direction (clockwise or counterclockwise) and rotation angle of the steering wheel are easy to understand. Furthermore, by applying markings, for example, to the outer peripheral surface of the spline portion, the rotation direction and rotation angle of the steering wheel can be recognized with even higher accuracy.

[0014] In a preferred embodiment, an axial gap is provided between a portion of the rotating member and the inner surface of the second housing, and an elastic member is accommodated in the gap to reduce the impact when the linear moving member abuts against the first abutment portion and the impact when the linear moving member abuts against the second abutment portion.

[0015] Therefore, when the linear moving member moves to one side in the axial direction and abuts against the first abutment portion, the first housing and the second housing move to one side in the axial direction, causing the elastic member to compress in the axial direction and reducing the impact when the linear moving member collides with the first abutment portion.

[0016] Furthermore, when the linear moving member moves to the other axial side and abuts against the second abutment portion, the second housing moves to the other axial side and the elastic member compresses in the axial direction, thereby reducing the impact. In this way, whether the linear moving member moves to one side or the other axial side, the elastic member can reduce the impact when the linear moving member hits the rotating member or the first housing.

[0017] In a preferred embodiment, a linear distance variable member having a thickness in the axial direction, with which the linear motion member can abut, and which changes the axial distance when the linear motion member moves linearly is interposed at least between the first abutment portion and the male thread portion and between the second abutment portion and the male thread portion.

[0018] Therefore, according to the present disclosure, with a simple configuration of a linear motion distance variable member, it is possible to change the axial distance when the linear motion member moves linearly, and ultimately to change the rotation angle of the steering wheel.

[0019] In a preferred aspect, the spline portion of the linear motion member is provided with a protrusion that is arranged on one axial side of an axial end face on one axial side of the first housing, protrudes radially, and abuts against the axial end face to stop the linear motion of the linear motion member toward one axial side.

[0020] When the linear motion member abuts against the second abutment portion, the non-rotating linear motion member abuts against the rotating second abutment portion, causing friction between the two and ultimately resulting in damage to the linear motion member and the second abutment portion due to wear.

[0021] In the present disclosure, both the linearly moving member and the first housing are non-rotating members. Therefore, when the linearly moving member moves linearly toward the other side in the axial direction, the non-rotating protrusion comes into contact with the non-rotating first housing. Therefore, according to the present disclosure, damage to the protrusion and the first housing can be suppressed.

[0022] According to the present disclosure, it is possible to provide a vehicle steering device equipped with a stopper mechanism portion that is easier to assemble.

[0023] FIG. 1 is a schematic diagram showing the overall configuration of a vehicle steering device according to a first embodiment. FIG. 2 is a cross-sectional view showing a portion of FIG. 1. FIG. 3 is a cross-sectional view showing a portion of FIG. 2. FIG. 4 is an enlarged cross-sectional view of a portion of FIG. 3. FIG. 5 is an exploded perspective view of a stopper mechanism according to the first embodiment. FIG. 6 is a cross-sectional view of a stopper mechanism according to a second embodiment. FIG. 7 is an enlarged cross-sectional view of part A in FIG. 6. FIG. 8 is a perspective view of a wave washer. FIG. 9 is a cross-sectional view of a stopper mechanism according to a third embodiment. FIG. 10 is a cross-sectional view of a stopper mechanism according to a fourth embodiment. FIG. 11 is a schematic view of FIG. 10 as viewed from the X1 side. FIG. 12 is a perspective view of a wheel chock. FIG. 13 is a schematic view of a modified example in which a pin is used as a protrusion.

[0024] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially identical. Furthermore, the components described below can be combined as appropriate. Furthermore, parts with the same structure are given the same reference numerals and their description will be omitted. In the coordinate system, the X direction indicates the axial direction of the rotating member, the X1 side is one side of the axial direction, and the X2 side is the other side of the axial direction.

[0025] [First embodiment] A first embodiment will be described below. Fig. 1 is a schematic diagram showing the overall configuration of a vehicle steering device according to the first embodiment. Fig. 2 is a cross-sectional view showing a part of Fig. 1. Fig. 3 is a cross-sectional view showing a part of Fig. 2. Fig. 4 is an enlarged cross-sectional view of a part of Fig. 3. Fig. 5 is an exploded perspective view of a stopper mechanism according to the first embodiment.

[0026] The vehicle steering device 100 according to this embodiment is a steer-by-wire type vehicle steering device, in which the steering wheel 10 is mechanically disconnected from the steered wheels 22. As shown in Fig. 1, the vehicle steering device 100 includes a steering unit 4, a control device (ECU) 14, and a steering unit 20.

[0027] As shown in FIGS. 1 to 3 , the steering unit 4 is provided with a steering reaction force device 13. When the steering wheel 10 is steered, the steering reaction force device 13 applies a steering reaction force to the steering wheel 10 in a direction opposite to the steering direction of the steering wheel 10. The control device (ECU) 14 calculates a reaction torque corresponding to the vehicle's driving state based on operation information, adjusts the power value supplied to the motor 110 of the steering reaction force device 13 based on the reaction torque, and operates the motor 110 according to the power value, thereby transmitting the steering reaction force of the steering wheel 10 to the operator. The control device (ECU) 14 also calculates a current command value based on the operation information and controls the current supplied to the steering motor 21 of the steering unit 20. In the steering unit 20, the steered wheels 22 are steered via various gears connected to the steering motor 21. Each component of the vehicle steering device 100 will be described in detail below. In the steer-by-wire vehicle steering device 100, the steering wheel 10 and the steered wheels 22 are mechanically disconnected from each other. However, in the present invention, "disconnected" also includes a mode in which the steering wheel 10 and the steered wheels 22 can be connected by a clutch device or the like in an emergency, for example.

[0028] As shown in FIG. 1 , the steering unit 4 includes a steering wheel 10 , a steering shaft 11 , a steering housing 12 , and a steering reaction force device 13 .

[0029] 2 and 3 , the steering shaft 11 extends in the X direction (axial direction). The steering wheel 10 is rotatably connected to the steering shaft 11. The steering shaft 11 is housed inside a steering housing 12. The steering shaft 11 has a column shaft 15, an output shaft 16, and a torsion bar 17.

[0030] The column shaft 15 and the output shaft 16 are connected via a torsion bar 17. Specifically, an insertion hole is provided in the X1 side end of the column shaft 15 in the axial direction, and the torsion bar 17 is inserted into this insertion hole. The column shaft 15 and the torsion bar 17 are connected to each other via a pin 122 so as not to rotate relative to each other. A through hole that passes through the output shaft 16 in the axial direction is provided, and the X1 side end of the torsion bar 17 is fitted into this through hole. In this way, the output shaft 16 and the torsion bar 17 are connected to each other so as not to rotate relative to each other. As described above, when the steering wheel 10 is rotated, the steering shaft 11 is connected and rotates.

[0031] The steering housing 12 also includes a shaft holding member 121 , rotation support members 123 and 124 , and a sub-housing 127 .

[0032] A rotation support member 123 is located on the X1 side of the shaft holding member 121, and a rotation support member 124 is located on the X1 side of the rotation support member 123. A sub-housing 127 is located on the X1 side of the rotation support member 124. A bearing 125 is provided radially inside the rotation support member 124, and a bearing 126 is provided radially inside the sub-housing 127. The output shaft 16 is rotatably supported via the bearings 125 and 126. In addition, a torque sensor 128 is provided between the rotation support member 123 and the rotation support member 124. The torque sensor 128 detects the rotational torque transmitted between the column shaft 15 and the output shaft 16.

[0033] Here, the steering reaction force device 13 has a steering shaft 11 , a worm wheel 18 , a worm shaft 19 , and a motor 110 .

[0034] A worm wheel 18 is attached to the outer periphery of the output shaft 16 of the steering shaft 11. The worm wheel 18 has a core metal portion 18a and wheel teeth portion 18b. The wheel teeth portion 18b is provided on the outer periphery of the core metal portion 18a. A worm shaft 19 and a motor 110 are located on the Y2 side (see FIG. 6) of the worm wheel 18. The worm shaft 19 is attached to the output shaft of the motor 110. The worm shaft 19 has shaft teeth portion 19a. The shaft teeth portion 19a mesh with the wheel teeth portion 18b.

[0035] The motor 110 generates a steering reaction force. That is, the output of the motor 110 becomes a reaction torque, and the reaction torque is transmitted from the steering shaft 11 to the steering wheel 10 via the worm wheel 18 and the worm shaft 19.

[0036] 2 and 3, a stopper mechanism 3 is provided on the X1 side of the output shaft 16 of the steering shaft 11. The stopper mechanism 3 will be described in detail below.

[0037] As shown in Figures 2 and 3, the rotating member 32 has a central axis AX, and the axial direction of the central axis AX coincides with the X direction. The rotating member 32 included in the stopper mechanism 3 is spline-fitted to the X1-side end of the output shaft 16 of the steering shaft 11. That is, a female spline 321a extending in the X direction is provided on the inner periphery of the rotating member 32, and a male spline extending in the X direction is provided on the outer periphery of the X1-side end of the output shaft 16. The male spline of the output shaft 16 is fitted into the female spline 321a of the rotating member 32. As a result, the rotating member 32 is movable in the X direction relative to the output shaft 16 but is unable to rotate in the circumferential direction around the central axis AX. That is, the rotating member 32 rotates integrally with the output shaft 16 in the direction around the central axis AX.

[0038] As shown in FIG. 4 , the stopper mechanism 3 includes a rotating member 32 , a linearly moving member 31 , a first housing 351 , and a second housing 352 .

[0039] The rotating member 32 has a central axis AX. The axial direction of the central axis AX is the X direction. The direction around the central axis AX is the circumferential direction. The direction perpendicular to the central axis AX is the radial direction. The rotating member 32 is a cylindrical member extending in the circumferential direction. The rotating member 32 includes a connecting portion 321 and a cylindrical portion 322.

[0040] The connecting portion 321 is located on the X2 side of the rotating member 32. The connecting portion 321 has a female spline 321a on its inner periphery. A second abutment portion 326 is provided on the inner surface of the connecting portion 321. The X2-side end face 311b of the male thread portion 311 can abut against the second abutment portion 326.

[0041] The cylindrical portion 322 is adjacent to the connecting portion 321 on the X1 side. The cylindrical portion 322 has a plurality of female threads 323 on its inner circumference. The rotating member 32 has an end surface 327 and an end surface 328. The end surfaces 327 and 328 are sandwiched between the first housing 351 and the second housing 352 in the X direction, thereby positioning the rotating member 32 in the X direction. The rotating member 32 has an outer peripheral surface 325. A radial gap is provided between the outer peripheral surface 325 and the large diameter portion 351c of the first housing 351.

[0042] The linear motion member 31 has a male threaded portion 311 and a splined portion 313. The linear motion member 31 extends in the X direction. The male threaded portion 311 has a plurality of male threads 312 formed on its outer periphery. The male threads 312 mesh with female threads 323. The splined portion 313 is located on the X1 side of the male threaded portion 311. A male spline 314 is formed on the outer periphery of the splined portion 313. The splined portion 313 has an axial end portion 313a at its end on the X1 side. A large diameter hole 315 is formed inside the male threaded portion 311. A small diameter hole 316 is formed inside the splined portion 313. The inner diameter of the large diameter hole 315 is larger than the inner diameter of the small diameter hole 316.

[0043] The first housing 351 has a small-diameter portion 351a, a medium-diameter portion 351b, and a large-diameter portion 351c. The medium-diameter portion 351b is adjacent to the large-diameter portion 351c on the X1 side, and the small-diameter portion 351a is adjacent to the medium-diameter portion 351b on the X1 side. A female spline 351f is provided on the inner periphery of the small-diameter portion 351a. The female spline 351f is spline-fitted with the male spline 314 of the linear motion member 31. As a result, the first housing 351 holds the linear motion member 31 in a state where it cannot rotate in the circumferential direction but can move linearly in the X direction. As a result, the linear motion member 31 moves linearly in the X direction relative to the rotating member 32 in a non-rotating state. The first housing 351 is also located on the outer periphery of the cylindrical portion 322 of the rotating member 32 and the linear motion member 31. The small diameter portion 351a is provided with a through hole 351g extending in the X direction. The axial end portion 313a of the linear motion member 31 can protrude toward the X1 side beyond the axial end face 351d of the small diameter portion 351a. A first abutment portion 351i is provided on the inner surface of the small diameter portion 351a. The first abutment portion 351i can abut against the end face 311a of the male thread portion 311.

[0044] The second housing 352 is located on the X2 side relative to the first housing 351. The second housing 352 is located on the outer periphery of the connecting portion 321. A mating portion 352a of the second housing 352 abuts against an end face 328 of the rotating member 32. A vertical wall portion 352c is provided at the end of the second housing 352 on the X2 side. An inner circumferential surface 352e of the vertical wall portion 352c supports the rotation of the connecting portion 321 of the rotating member 32. An axial end face 351e of the first housing 351 abuts against an axial end face 352d of the second housing 352. Here, the axial end face 351e and the axial end face 352d form a divided portion 300 between the first housing 351 and the second housing 352. This divided portion can be provided in various locations, such as divided portion 300A and divided portion 300B shown in FIG. 4 . That is, the first housing 351 and the second housing 352 can be divided at various locations, without being limited to the divided portions 300, 300A, and 300B shown in the drawings.

[0045] As shown in FIG. 5 , the second housing 352 has flanges 351h that protrude toward the Y1 side and the Y2 side. A first bolt hole H1 is provided in the flange 351h. The male threaded portion of the bolt BL passes through the first bolt hole H1. The first housing 351 has flanges 352b that protrude toward the Y1 side and the Y2 side. A second bolt hole H2 is provided in the flange 352b. The second bolt hole H2 has a female threaded portion on its inner periphery that engages with the male threaded portion of the bolt BL.

[0046] Next, a brief description will be given of the procedure for assembling the stopper mechanism 3. First, the linear motion member 31 is assembled to the rotating member 32 from the X1 side toward the X2 side. Specifically, the male thread 312 of the linear motion member 31 is fastened to the female thread 323 of the rotating member 32 from the X1 side toward the X2 side.

[0047] Next, the first housing 351 is inserted from the X1 side toward the X2 side around the outer periphery of the rotating member 32 and the linearly moving member 31. Then, the second housing 352 is attached to the first housing 351 by moving it from the X2 side toward the X1 side. Specifically, with the first bolt hole H1 and the second bolt hole H2 aligned, the flanges 351h and 352b are butted against each other. The bolt BL is inserted into the first bolt hole H1 and engaged with the female thread of the second bolt hole H2. This completes the assembly of the stopper mechanism 3.

[0048] The first abutment portion 351i is located at the end on the X1 side when the linear moving member 31 moves linearly. The second abutment portion 326 is located at the end on the X2 side when the linear moving member 31 moves linearly. That is, the linear moving member 31 abuts against the first abutment portion 351i at the end abutment position when the steering wheel 10 is rotated, for example, clockwise. The linear moving member 31 abuts against the second abutment portion 326 at the end abutment position when the steering wheel 10 is rotated, for example, counterclockwise. In other words, the steering wheel 10 can be rotated in a range from the position where the linear moving member 31 abuts against the first abutment portion 351i to the position where it abuts against the second abutment portion 326.

[0049] As described above, in the first embodiment, the stopper mechanism 3 includes a rotating member 32 having a connecting portion 321 and a cylindrical portion 322, a linear motion member 31, a first housing 351 located on the outer periphery of the cylindrical portion 322 and the linear motion member 31, and a second housing 352 located on the X2 side of the first housing 351 and on the outer periphery of the connecting portion 321.

[0050] As mentioned above, in Patent Document 1, the assembly work of the stopper mechanism is complicated and may result in a large workload. Specifically, the first housing is attached to the outer periphery of the steering shaft. Next, a stopper unit having a rotating member, a nut, a first stopper portion, and a second stopper portion is assembled. The stopper unit is inserted (spline-fitted) toward one side of the steering shaft in the axial direction and abutted against the first housing, and then the second housing is fitted from one side of the steering shaft in the axial direction, thereby completing the assembly work of the stopper mechanism.

[0051] In contrast to this, according to this embodiment, the stopper mechanism portion 3 can be assembled by the following simple procedure.

[0052] Specifically, first, the male thread 312 of the linear motion member 31 is fastened to the female thread 323 of the rotating member 32 from the X1 side to the X2 side, and the linear motion member 31 is assembled to the rotating member 32 from the X1 side to the X2 side. Next, the first housing 351 is inserted around the outer periphery of the rotating member 32 and the linear motion member 31 from the X1 side to the X2 side, and the second housing 352 is attached to the first housing 351.

[0053] As described above, according to this embodiment, it is possible to provide a vehicle steering device 100 that includes a stopper mechanism portion 3 that can be assembled more easily.

[0054] A through hole 351g is provided at the end of the first housing 351 on the X1 side, and the spline portion 313 of the linear motion member 31 can protrude from the through hole 351g on the X1 side.

[0055] When the steering wheel 10 is rotated, the steering shaft 11 and the rotating member 32 rotate, and the linear moving member 31 moves in the X direction. If the linear moving member 31 is housed inside a housing and cannot be seen from the outside, the position of the linear moving member 31 in the X direction cannot be determined, and therefore the rotation direction (clockwise or counterclockwise) of the steering wheel 10 and the rotation angle cannot be determined.

[0056] In contrast, in this embodiment, the spline portion 313 of the linear motion member 31 can protrude from the through-hole 351g to the X1 side, making it possible to visually confirm the rotation direction and rotation angle of the steering wheel 10. Note that, for example, by applying a marking to the outer peripheral surface of the spline portion 313, the rotation direction and rotation angle of the steering wheel 10 can be recognized with even higher accuracy.

[0057] [Second embodiment] A second embodiment will be described below. Fig. 6 is a cross-sectional view of a stopper mechanism according to the second embodiment. Fig. 7 is an enlarged cross-sectional view of part A in Fig. 6. Fig. 8 is a perspective view of a wave washer.

[0058] The second embodiment differs from the first embodiment in that a wave washer 341 (elastic member 34) is added. The following description will focus on this difference.

[0059] As shown in FIG. 6 , the stopper mechanism 3A according to the second embodiment includes a rotating member 32A. The rotating member 32A has a protrusion 320 provided on a connecting portion 321. The protrusion 320 protrudes toward the X2 side. The second housing 352A also has a recess 352Ad. The recess 352Ad is recessed toward the X2 side. A wave washer 341 (elastic member 34) is housed inside the recess 352Ad.

[0060] As shown in Figure 8, the wave washer 341 has an inner peripheral edge 345 on the radially inner side and an outer peripheral edge 344 on the radially outer side. Furthermore, bent portions 342 and 343 are alternately arranged along the circumferential direction. The bent portion 342 is convex toward the X2 side, and the bent portion 343 is convex toward the X1 side. Note that the wave washer 341 is an example of the elastic member 34, and various elastic members other than the wave washer 341, such as a disc spring, can also be used. Next, the effect of the wave washer 341 in the stopper mechanism 3A will be briefly described.

[0061] First, in FIG. 6, when the linear motion member 31 moves linearly in the X1 direction and the end face 311a abuts against the first abutment portion 351i as indicated by the arrow D1, the first housing 351 moves in the X1 direction as indicated by the arrow D2.

[0062] Because the second housing 352A is fixed to the first housing 351, the second housing 352A also moves toward the X1 side as shown by the arrow D3 in Figures 6 and 7. This causes the wave washer 341 to contract in the X direction, reducing the impact.

[0063] When the linear motion member 31 moves linearly in the X2 direction and the end face 311b abuts against the second abutment portion 326, the second housing 352A moves in the X2 direction, causing the wave washer 341 to contract in the X direction and reduce the impact.

[0064] As described above, in the second embodiment, in the stopper mechanism 3A, the wave washer 341 (elastic member 34) is housed in the recess 352Ad of the second housing 352A.

[0065] Therefore, when the linear motion member 31 moves toward the X1 side and comes into contact with the first contact portion 351i, the first housing 351 and the second housing 352A move toward the X1 side, causing the wave washer 341 to contract in the X direction and reduce the impact.

[0066] Furthermore, when the linear motion member 31 moves to the X2 side and the end face 311b abuts against the second abutment portion 326, the connecting portion 321 moves to the X2 side, and the wave washer 341 contracts in the X direction to reduce the impact.

[0067] In this way, whether the linear moving member 31 moves to the X1 side or the X2 side, the wave washer 341 can reduce the impact when the rotating member 32 or the first housing 351 hits the linear moving member 31.

[0068] Third Embodiment A third embodiment will now be described with reference to Fig. 9, which is a cross-sectional view of a stopper mechanism according to the third embodiment.

[0069] The third embodiment differs from the first embodiment in that a linear motion distance variable member is added. The following description will focus on this difference.

[0070] As shown in FIG. 9 , in the stopper mechanism 3B according to the third embodiment, a linear motion distance variable member 51 is disposed between the first abutment portion 351i and the end surface 311a. The linear motion distance variable member 51 is an annular member extending in a direction around the central axis AX and has a thickness in the axial direction. The linear motion member 31 can abut against the linear motion distance variable member 51. The rigidity of the linear motion distance variable member 51 is, for example, equal to or greater than the rigidity of the linear motion member 31. The linear motion distance variable member 51 is made of, for example, resin. When the linear motion member 31 abuts against the linear motion distance variable member 51, the axial distance of the linear motion member 31 during linear motion is changed. The axial distance of the linear motion member 31 is reduced by the thickness of the linear motion distance variable member 51.

[0071] Additionally, a linear motion distance variable member 52 is disposed between the second abutment portion 326 and the end surface 311a. The linear motion distance variable member 52 is an annular member extending in a direction around the central axis AX and has a thickness in the axial direction. The linear motion member 31 can abut against the linear motion distance variable member 52. The linear motion distance variable member 52 includes a disk portion 522 and a flange portion 521. The flange portion 521 protrudes from the peripheral edge of the disk portion 522 toward the X2 side. The flange portion 521 extends in the circumferential direction. The rigidity of the linear motion distance variable member 52 is, for example, equal to or greater than the rigidity of the linear motion member 31. The linear motion distance variable member 52 is made of, for example, resin. When the linear motion member 31 abuts against the linear motion distance variable member 52, the axial distance of the linear motion member 31 is changed during linear motion. The axial distance of the linear motion member 31 is reduced by the thickness of the linear motion distance variable member 52.

[0072] It is to be noted that both the linear motion distance variable member 5 and the linear motion distance variable member 52 may be provided, or only one of them may be provided.

[0073] As described above, in the third embodiment, the stopper mechanism 3B is provided with the linear motion distance variable member 5. The linear motion distance variable member 5 is, for example, the linear motion distance variable members 51 and 52.

[0074] Therefore, according to this embodiment, the linear motion distance variable member 5 has a simple configuration, and it is possible to change the axial distance when the linear motion member 31 moves linearly, and therefore to change the rotation angle of the steering wheel 10.

[0075] [Fourth embodiment] A fourth embodiment will be described below. Fig. 10 is a cross-sectional view of a stopper mechanism according to the fourth embodiment. Fig. 11 is a schematic view of Fig. 10 as seen from the X1 side. Fig. 12 is a perspective view of a ring stopper. Fig. 13 is a schematic view of a modified example in which a pin is used as a protrusion. Note that Fig. 13 is a view of Fig. 10 as seen from the X1 side.

[0076] The fourth embodiment differs from the first embodiment in that a wheel stopper 61 or a pin 62 is added. The following description will focus on this difference.

[0077] As shown in FIGS. 10 to 12 , in a stopper mechanism 3C according to the fourth embodiment, a ring stopper 61 (protrusion 6) that protrudes radially is provided on a spline portion 313 of a linear motion member 31. The ring stopper 61 is an example of a protrusion 6. Specifically, the ring stopper 61 is attached to the X1-side end of the spline portion 313. A groove is provided in the spline portion 313 along the circumferential direction, and the ring stopper 61 is fitted into the groove. The ring stopper 61 is located on the X1 side of an axial end face 351d of the first housing 351 and faces the axial end face 351d. The ring stopper 61 acts as a stopper that stops the linear motion of the linear motion member 31 toward the X2 side.

[0078] Note that a pin 62 shown in FIG. 13 can also be used as the protrusion 6. Specifically, the pin 62 is attached to the end of the spline portion 313 on the X1 side. A groove is provided in the spline portion 313, and the pin 62 is fitted into the groove. The pin 62 is located on the X1 side of the axial end face 351d of the first housing 351, and faces the axial end face 351d. The pin 62 acts as a stopper that stops the linear motion of the linearly moving member 31 toward the X2 side.

[0079] As described above, in the fourth embodiment, in the stopper mechanism 3C, the protrusion 6 is provided on the spline portion 313 of the linear motion member 31. The protrusion 6 is, for example, a ring stopper 61 or a pin 62. The protrusion 6 protrudes in the radial direction and abuts against the axial end face 351d to stop the linear motion of the linear motion member toward the X1 side.

[0080] When the end face 311b of the linear motion member 31 abuts against the second abutment portion 326, the non-rotating end face 311b and the rotating second abutment portion 326 abut against each other, causing friction between the two and potentially damaging the end face 311b and the second abutment portion 326 due to wear.

[0081] In this embodiment, both the linear motion member 31 and the first housing 351 are non-rotating members. Therefore, when the linear motion member 31 moves linearly toward the X2 side, the non-rotating protrusion 6 comes into contact with the axial end surface 351d of the non-rotating first housing 351. Therefore, according to this embodiment, damage to the protrusion 6 and the axial end surface 351d can be suppressed.

[0082] 3, 3A, 3B, 3C Stopper mechanism 4 Steering unit 5 Linear motion distance variable member 6 Protrusion 10 Steering wheel 11 Steering shaft 12 Steering housing 13 Steering reaction force device 14 Control device (ECU) 15 Column shaft 16 Output shaft 17 Torsion bar 18 Worm wheel 18a Core metal portion 18b Wheel tooth portion 19 Worm shaft 19a Shaft tooth portion 20 Turning unit 21 Turning motor 22 Turned wheel 31 Linear motion member 32, 32A Rotating member 34 Elastic member 51 Linear motion distance variable member 52 Linear motion distance variable member 61 Wheel stopper (protrusion) 62 Pin (protrusion) 100 Vehicle steering device 311 Male thread portion 311a End face 311b End face 312 Male thread 313 Spline portion 313a Axial end portion 314 Male spline 315 Large diameter hole 316 Small diameter hole 320 Projection portion 321 Connecting portion 321a Female spline 322 Cylindrical portion 323 Female thread 325 Outer circumferential surface 326 Second abutment portion 327, 328 End surface 341 Wave washer 342, 343 Bent portion 344 Outer circumferential edge 345 Inner circumferential edge 351 First housing 351a Small diameter portion 351b Medium diameter portion 351c Large diameter portion 351d Axial end face 351e Axial end face 351f Female spline 351g Through hole 351h Flange 351i First abutment portion 352 Second housing 352a Mating portion 352b Flange 352d Axial end surface 352A Second housing 352Ad Recess 521 Flange portion 522 Disk portion BL Bolt H1 First bolt hole H2 Second bolt hole

Claims

1. A steering device for a vehicle in which a steering shaft to which a steering wheel is connected is mechanically not connected to steered wheels, the steering device comprising: a stopper mechanism for restricting the range of rotation angle of the steering wheel when the steering wheel is rotated, the stopper mechanism comprising: a rotating member extending in the axial direction of a central axis and rotatable in the circumferential direction around the central axis, the rotating member having a connecting portion connected to the steering shaft and a tubular portion located on one side of the connecting portion in the axial direction and having a female thread on its inner circumference; a linear motion member provided on the inner circumference of the tubular portion, having a male thread on its outer circumference that meshes with the female thread, and performing linear motion in the axial direction relative to the rotating member; a first housing located on the outer circumference of the tubular portion and the linear motion member, and holding the linear motion member in a state in which it cannot rotate in the circumferential direction but can perform linear motion in the axial direction; and a second housing located on the other axial side of the first housing and on the outer circumference of the connecting portion, the second housing being attached to the first housing. a first abutment portion and a second abutment portion with which the linear motion member abuts, thereby stopping linear motion.

2. A vehicle steering device as described in claim 1, wherein the first housing has an inner periphery provided with a female spline, the linear motion member has a male threaded portion having the male thread and capable of abutting the first abutment portion and the second abutment portion, and a spline portion located on one axial side of the male threaded portion and having a male spline on its outer periphery capable of engaging with the female spline, the first housing has an end on one axial side provided with a through hole penetrating in the axial direction, and when the linear motion member moves linearly towards one axial side, the spline portion of the linear motion member can protrude from the through hole of the first housing to one axial side.

3. A vehicle steering device as claimed in claim 1 or 2, wherein an axial gap is provided between a part of the rotating member and an inner surface of the second housing, and an elastic member is accommodated in the gap to reduce the impact when the linear moving member abuts against the first abutment portion and the impact when the linear moving member abuts against the second abutment portion.

4. A vehicle steering device as described in claim 2, wherein a linear distance variable member having a thickness in the axial direction and capable of contacting the linear motion member and changing the axial distance when the linear motion member moves linearly is interposed at least between the first abutment portion and the male threaded portion and between the second abutment portion and the male threaded portion.

5. A vehicle steering device as described in claim 4, wherein the spline portion of the linear motion member is provided with a protrusion that is arranged on one axial side of an axial end face on one axial side of the first housing, protrudes radially, and abuts against the axial end face to stop linear motion of the linear motion member towards one axial side.

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