Vehicle steering device

Abstract

This vehicle steering device includes: a rotating member that includes a male threaded section and a cylindrical surface section; a nut that moves in the X direction relative to the rotating member in a non-rotating state; an annular member that is inserted into the cylindrical surface section and is movable in the X direction; and a housing. The annular member has a flat plate-shaped vertical wall section. In the male threaded section of the rotating member, a first incomplete thread is arranged at one axial side end, and a second incomplete thread is arranged at the other axial side end. An axial end surface section and a separation section are provided on one axial side surface of the first incomplete thread. An axial end surface section and a separation section are provided on the other axial side surface of the second incomplete thread.

Description

Vehicle steering device

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

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

[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] In Patent Document 1, the stopper mechanism includes a rotating member that rotates with the steering wheel and has a male thread on its outer periphery, a nut that has a female thread on its inner periphery and moves linearly in the axial direction relative to the rotating member, and a stopper that stops the linear movement of the nut. The rotating member has a male thread and a cylindrical surface that is axially adjacent to the male thread. The stopper has an annular member that fits around the outer periphery of the cylindrical surface, and a leaf spring that fits around the outer periphery of the annular member.

[0005] German Patent No. 102020126785

[0006] The male thread portion includes a complete thread portion and an incomplete thread portion adjacent to both axial sides of the complete thread portion. Because the incomplete thread portion has lower strength than the complete thread, in Patent Document 1, a cylindrical surface portion is provided axially outward and inward of the axial end of the incomplete thread portion to prevent the annular member and the leaf spring from contacting the incomplete thread. Therefore, the stopper mechanism according to Patent Document 1 is large in the axial direction, which may result in an increase in the size of the vehicle steering device.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a vehicle steering device that is more compact.

[0008] In order to achieve the above object, a vehicle steering device according to one embodiment is a vehicle steering device in which a steering wheel and steered wheels are mechanically disconnected, and includes a stopper mechanism that restricts the range of rotation angle of the steering wheel when the steering wheel is rotated, the stopper mechanism including: a male thread portion having a male thread including a complete thread and an incomplete thread provided on an outer periphery thereof; and a pair of cylindrical surface portions adjacent to the male thread portion on one side and the other side in the axial direction of a central axis and having cylindrical surfaces with a diameter smaller than the outer diameter of the male thread portion, the stopper mechanism including a rotating member that rotates in a circumferential direction around the central axis in response to the rotation of the steering wheel; a nut that has a female thread that meshes with the male thread on its inner periphery and moves in the axial direction relative to the rotating member as the rotating member rotates; and a pair of cylindrical surface portions inserted into each of the pair of cylindrical surface portions of the rotating member and that are connected to the nut. and a housing arranged on the outer circumferential side of the rotating member, the nut, and the pair of annular members, and supporting each of the pair of annular members between the rotating member and the nut. The male thread portion of the rotating member has a first incomplete thread arranged at one axial end and a second incomplete thread arranged at the other axial end, and the complete thread arranged between the first incomplete thread and the second incomplete thread. One axial surface of the first incomplete thread is provided with an axial end face portion extending along a first plane perpendicular to the central axis, and a separated portion spaced apart on the other axial side from the first plane. The other axial surface of the second incomplete thread is provided with an axial end face portion extending along a second plane perpendicular to the central axis, and a separated portion spaced apart on one axial side from the second plane.

[0009] As described above, in the stopper mechanism disclosed in Patent Document 1, because an incomplete thread has less strength than a complete thread, a cylindrical surface portion is provided axially outward and inward of the axial end of the incomplete thread portion to prevent the annular member and leaf spring from contacting the incomplete thread. The annular member is then fitted onto the cylindrical surface portion, and the leaf spring is fitted onto the outer periphery of the annular member. As a result, the stopper mechanism disclosed in Patent Document 1 becomes larger in the axial direction, which may ultimately result in an increased size of the vehicle steering device.

[0010] In contrast, in the stopper mechanism according to the present disclosure, the axial end face portion on one axial side of the first incomplete thread abuts against the nut-side end face of the vertical wall portion of the annular member, and the axial end face portion on the other axial side of the second incomplete thread abuts against the nut-side end face of the vertical wall portion of the annular member.

[0011] Therefore, in the present disclosure, when the nut moves to one side in the axial direction due to rotation of the rotating member and the axial end face of the nut abuts on the vertical wall portion of the annular member, the rotating member is pushed to the other side, and an axial gap is generated between the rotating member and the annular member on one side in the axial direction. The rotating member pushed to the other side compresses the annular member on the other side, and the resulting reaction force pushes back the axial end face portion of the second incomplete thread to one side, but the separation portion does not abut on the vertical wall portion.

[0012] That is, when the stopper mechanism is viewed from the side (in the radial direction perpendicular to the central axis), the portion of the annular member that abuts the axial end face behaves as if it bulges toward the nut, while the portion facing the separator does not change thickness. Therefore, when viewed from the side, the annular member is compressed but does not exhibit rotational behavior. Therefore, compared to when the annular member does not rotate (oscillate), the reaction force exerted by the annular member on the first incomplete thread and the second incomplete thread is smaller, making the first incomplete thread and the second incomplete thread less likely to be damaged.

[0013] In this manner, in the stopper mechanism according to the present disclosure, the rotating member is pushed in the direction opposite to the movement direction of the nut, compressing the annular member, and the annular member pushes back the incomplete thread portion due to the reaction force, thereby further reducing the force applied by the annular member to the first and second incomplete threads. This allows the annular member to abut against the first and second incomplete threads. Furthermore, because the first and second incomplete threads abut against the annular member, the axial size can be set smaller than in Patent Document 1, thereby making it possible to provide a more compact vehicle steering device.

[0014] In a preferred aspect, when the rotating member is viewed from the axial direction, the axial end surface portion of the first incomplete thread and the axial end surface portion of the second incomplete thread are arranged on the same side of the central axis.

[0015] As described above, when the nut moves to one side in the axial direction due to rotation of the rotating member and the axial end face portion of one side of the nut abuts the vertical wall portion of the annular member on one side, the rotating member is pushed to the other side, compressing the annular member on the other side, and the resulting reaction force causes the rotating member to swing, for example, in a clockwise direction when viewed radially.

[0016] Furthermore, when the nut moves to the other axial side due to rotation of the rotating member and the axial end face portion of the nut on the other side abuts against the vertical wall portion of the annular member on the other side, the vertical wall portion is compressed and the resulting reaction force causes the rotating member to swing counterclockwise when viewed from the radial direction.

[0017] In this way, when the nut moves to one side in the axial direction and when it moves to the other side, the swinging direction of the rotating member as viewed from the radial direction is opposite to each other, thereby preventing localized loads from being continuously applied to specific parts of the annular member.

[0018] In a preferred aspect, when the rotating member is viewed from the axial direction, the axial end surface portion of the first incomplete thread and the axial end surface portion of the second incomplete thread are arranged on opposite sides of the central axis.

[0019] As described above, when the nut moves to one side in the axial direction due to rotation of the rotating member and the axial end face portion of one side of the nut abuts the vertical wall portion of the annular member on one side, the rotating member is pushed to the other side, compressing the annular member on the other side, and the resulting reaction force causes the rotating member to swing, for example, in a clockwise direction when viewed radially.

[0020] Furthermore, when the nut moves to the other axial side due to rotation of the rotating member and the other axial end face of the nut abuts against the vertical wall portion of the other annular member, the vertical wall portion is compressed.

[0021] Here, when the rotating member is viewed from the axial direction, the axial end face portion of the first incomplete thread and the axial end face portion of the second incomplete thread are disposed on opposite sides of the central axis. Therefore, the axial end face portion of the first incomplete thread and the axial end face portion of the second incomplete thread are disposed on the same side of the central axis, which is the opposite of the case where they are disposed on the same side of the central axis, and the reaction force of the vertical wall portion against the compression causes the rotating member to swing clockwise when viewed from the radial direction.

[0022] In this way, when the nut moves to one side in the axial direction, the direction of oscillation of the rotating member as viewed from the radial direction is the same. In this case, there is a possibility that a local load will be applied to a specific part of the annular member, but for example, if the rotating member is rotated, for example, 180 degrees around the central axis after a predetermined period of time has elapsed, the continuous application of the local load to the specific part of the annular member can be suppressed.

[0023] In a preferred embodiment, at least one of the pair of annular members includes a main body and a coating layer provided on the surface of the main body, and the elastic modulus of the coating layer is smaller than that of the main body. This makes it possible to reduce contact noise (interference noise) when the nut contacts the annular member. A material that reduces the friction coefficient with the mating material may be selected for the coating layer to prevent the nut from getting caught when it contacts the annular member. Alternatively, grease lubrication may be used instead of the coating layer.

[0024] In a preferred embodiment, at least one of the pair of annular members has a protruding portion that protrudes axially toward the nut and is capable of coming into contact with the nut.

[0025] This reduces the axial movement distance of the nut relative to the annular member without a protrusion, thereby reducing the limit range of the steering angle of the steered wheels and allowing the steering wheel to be rotated at a smaller angle.

[0026] In a preferred embodiment, the housing has a cylindrical housing body portion extending in a circumferential direction, and a sealing portion that seals one axial side of the housing body portion.

[0027] In this way, the housing is sealed by the sealing portion, which prevents foreign matter such as dust from entering the inside of the housing and also prevents oil inside the housing from leaking to the outside.

[0028] In a preferred embodiment, the housing has a cylindrical housing main body portion that extends circumferentially and is open on one axial side, a protrusion portion that is arranged at the end of one axial side of the housing main body portion and has a recess that protrudes toward the inner circumference and is recessed toward the outer circumference, and a sealing member that is accommodated in the recess, and the annular member is arranged on the inner circumference side of the recess of the protrusion, and the tip of the inner circumference side of the sealing member can abut against the outer circumference surface of the annular member.

[0029] Because the housing main body has an opening, there is a possibility that foreign matter such as dust may enter the housing through the opening. However, the tip of the seal member abuts against the annular member, preventing the entry of foreign matter. The seal member also prevents oil from leaking from inside the housing to the outside.

[0030] According to the present disclosure, it is possible to provide a more compact vehicle steering device.

[0031] 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 a cross-sectional view of a stopper mechanism according to the first embodiment. FIG. 5 is an enlarged cross-sectional view of a portion of FIG. 4. FIG. 6 is an exploded perspective view of the stopper mechanism according to the first embodiment. FIG. 7 is a perspective view of the rotating member of FIG. 6. FIG. 8 is a side view of the rotating member of FIG. 6. FIG. 9 is a schematic view of the rotating member of FIG. 8 as viewed from direction A. FIG. 10 is a schematic view of the rotating member of FIG. 8 as viewed from direction B. FIG. 11 is a side view of a rotating member according to a modified example. FIG. 12 is a schematic view of the rotating member of FIG. 11 as viewed from direction A. FIG. 13 is a schematic view of the rotating member of FIG. 11 as viewed from direction B. FIG. 14 is a cross-sectional view of a stopper mechanism according to a second embodiment. FIG. 15 is an enlarged cross-sectional view of the first annular member of FIG. 14. FIG. 16 is a cross-sectional view of a stopper mechanism according to a third embodiment. Fig. 17 is a cross-sectional view of a stopper mechanism according to a fourth embodiment. Fig. 18 is a cross-sectional view of a stopper mechanism according to a fifth embodiment.

[0032] 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.

[0033] [First embodiment] A first embodiment will be described. Fig. 1 is a schematic diagram showing the overall configuration of a vehicle steering device of 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.

[0034] 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 .

[0035] As shown in Figures 1 to 3, the steering unit 4 is provided with a steering reaction force device 13. When the steering wheel 10 is rotated for steering, the steering reaction force device 13 applies a steering reaction force to the steering wheel 10 in a direction opposite to the direction of rotation of the steering wheel 10. An electronic control unit (ECU) 14 calculates a reaction torque according to the vehicle's running 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. In the steer-by-wire vehicle steering device 100, the steering wheel 10 and the steered wheels 22 are mechanically disconnected. However, in the present invention, "disconnection" 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, for example, in an emergency.

[0036] Furthermore, the control device (ECU) 14 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.

[0037] 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 .

[0038] 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.

[0039] 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 so that they cannot rotate relative to each other via a pin 122. 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 that they cannot rotate relative to each other. As described above, when the steering wheel 10 is rotated, the steering shaft 11 also rotates.

[0040] The steering housing 12 also includes a shaft holding member 121 , rotation support members 123 and 124 , and a sub-housing 127 .

[0041] 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.

[0042] Here, the steering reaction force device 13 has a steering shaft 11 , a worm wheel 18 , a worm shaft 19 , and a motor 110 .

[0043] 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.

[0044] 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.

[0045] As shown in Figures 2 and 3, the rotating member 31 has a central axis AX, and the axial direction of the central axis AX coincides with the X direction. The rotating member 31 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 319 extending in the X direction is provided on the inner periphery of the rotating member 31, 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 319 of the rotating member 31. As a result, the rotating member 31 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 31 rotates integrally with the output shaft 16.

[0046] As shown in Figures 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. Figure 4 is a cross-sectional view of the stopper mechanism according to the first embodiment. Figure 5 is an enlarged cross-sectional view of a portion of Figure 4. Figure 6 is an exploded perspective view of the stopper mechanism according to the first embodiment.

[0047] As shown in FIG. 4 , the stopper mechanism 3 includes a rotating member 31 , a nut 32 , a first annular member 331 , a second annular member 331A, and a housing 35 .

[0048] 4 and 5, the rotating member 31 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 31 includes a male thread portion 311, a first cylindrical surface portion 312, and a second cylindrical surface portion 312A.

[0049] The male thread portion 311 has a male thread 310 on its outer periphery. The male thread 310 has a bottom portion 310a. The male thread 310 includes a complete thread 314, a first incomplete thread 315, and a second incomplete thread 316. The first incomplete thread 315 is located at the end closest to the X1 side, and the second incomplete thread 316 is located at the end closest to the X2 side.

[0050] The first cylindrical surface portion 312 is adjacent to the male thread portion 311 on the X1 side. The first cylindrical surface portion 312 has a cylindrical surface 313. The cylindrical surface 313 extends in the circumferential direction about the central axis AX. The diameter of the cylindrical surface 313 is smaller than the outer diameter of the male thread portion 311. The second cylindrical surface portion 312A is adjacent to the male thread portion 311 on the X2 side. The second cylindrical surface portion 312A has the cylindrical surface 313. The end of the rotating member 31 on the X1 side has an axial end face 317, and the end of the rotating member 31 on the X2 side has an axial end face 318. The rotating member 31 will be described in further detail below.

[0051] The nut 32 is provided on the outer circumferential side of the rotating member 31. The nut 32 has an internal thread 321 on its internal circumferential side. The internal thread 321 meshes with the external thread 310 of the rotating member 31. The outer circumferential surface 324 of the nut 32 is a cylindrical surface extending in the circumferential direction. The end of the nut 32 on the X1 side has an axial end face 322, and the end of the nut 32 on the X2 side has an axial end face 323. The axial end face 322 of the nut 32 can abut against the vertical wall portion 332 of the first annular member 331. The axial end face 323 of the nut 32 can abut against the vertical wall portion 332A of the second annular member 331A.

[0052] The first annular member 331 has an annular shape extending in the circumferential direction. The first annular member 331 is inserted into the first cylindrical surface portion 312. The inner diameter of the first annular member 331 is larger than the outer diameter of the first cylindrical surface portion 312. Therefore, the first annular member 331 is movable in the X direction while inserted into the first cylindrical surface portion 312. The first annular member 331 has a vertical wall portion 332 and a tubular portion 333. The vertical wall portion 332 extends radially outward. The tubular portion 333 extends in the circumferential direction. The vertical wall portion 332 and the tubular portion 333 are connected via a corner portion 334.

[0053] A second annular member 331A is inserted into the second cylindrical surface portion 312A. The second annular member 331A has a vertical wall portion 332A and a tubular portion 333A. The vertical wall portion 332A extends radially outward. The vertical wall portion 332A is disposed facing the X2 side of the nut 32. The tubular portion 333A extends circumferentially. The vertical wall portion 332A and the tubular portion 333A are connected via a corner portion 334A.

[0054] The housing 35 is disposed on the outer circumferential side of the rotating member 31, the nut 32, the first annular member 331, and the second annular member 331A. The housing 35 includes a first housing 351 and a second housing 352.

[0055] The first housing 351 is disposed on the X2 side of the housing 35. The first housing 351 has a connecting portion 351a, a vertical wall portion 351b, a cylindrical portion 351c, and a flange 351d.

[0056] The coupling portion 351a fits into and is coupled to the coupled portion 352a of the second housing 352. The vertical wall portion 351b extends radially, and the cylindrical portion 351c extends circumferentially. A second bolt hole H2 is provided in the flange 351d. An internal thread is provided on the inner periphery of the second bolt hole H2, and the internal thread engages with the external thread of the bolt BL.

[0057] The second housing 352 has a coupled portion 352a, a cylindrical portion 352b, a radial wall portion 352c, and a flange 352h.

[0058] The cylindrical portion 352b extends in the circumferential direction. The radial wall portion 352c extends in the radial direction. A through hole 353 is provided in the radial center of the radial wall portion 352c, and the first annular member 331 and the rotating member 31 are fitted into the through hole 353. A first bolt hole H1 is provided in the flange 352h. A through hole is provided in the inner periphery of the first bolt hole H1, and the shank of the bolt BL passes through the through hole. Therefore, the flange 351d and the flange 352h are fastened together via the bolt BL.

[0059] As shown in FIG. 5 , the outer diameters of the first annular member 331 and the second annular member 331A are both a first outer diameter D1. Specifically, a first radial distance between the outer peripheral end of the vertical wall portion 332 of the first annular member 331 and the central axis AX is the same as a second radial distance between the outer peripheral end of the vertical wall portion 332A of the second annular member 331A and the central axis AX. The first outer diameter D1 is twice the first distance or twice the second distance. The outer diameter of the cylindrical surface 313 is a second outer diameter D2. The second outer diameter D2 is the same as the diameter of the bottom portion 310a of the male thread 310. The first outer diameter D1 is larger than the second outer diameter D2.

[0060] Next, with reference to FIG. 6 , the assembly procedure for the stopper mechanism 3 will be briefly described. As shown in FIG. 6 , first, the rotating member 31 is fastened to the inner periphery of the nut 32, the first annular member 331 is inserted into the first cylindrical surface portion 312 of the rotating member 31, and the second annular member 331A is inserted into the second cylindrical surface portion 312A. Next, in this state, the rotating member 31, the nut 32, the first annular member 331, and the second annular member 331A are inserted into the inside of the second housing 352. At this time, the protrusion 325 is fitted into the groove 352j. Then, the first housing 351 is bolted to the second housing 352. Specifically, the flange 351d is butted against the flange 352h, and the second bolt hole H2 and the first bolt hole H1 are connected. Then, the bolt BL is passed through the first bolt hole H1 and engaged with the female thread of the second bolt hole H2, thereby completing the assembly of the stopper mechanism 3. As described above, since the protrusion 325 of the nut 32 fits into the groove 352j of the second housing 352, the nut 32 moves linearly in the X direction without rotating relative to the second housing 352.

[0061] Next, the configuration of the rotating member 31 will be described. Fig. 7 is a perspective view of the rotating member of Fig. 6. Fig. 8 is a side view of the rotating member of Fig. 6. Fig. 9 is a schematic view of the rotating member of Fig. 8 as seen from direction A. Fig. 10 is a schematic view of the rotating member of Fig. 8 as seen from direction B.

[0062] First, in the rotating member 31 according to the embodiment, when viewed from the X direction, the axial end surface portion 315a and the axial end surface portion 316a are located on the same Z1 side with respect to a line L perpendicular to the central axis AX, as shown in FIGS. 9 and 10 . The line L extends in the Y direction. As shown in FIG. 8 , in the rotating member 31, a first incomplete thread 315 is disposed at the end of the male thread portion 311 closest to the X1 side. The axial end surface portion 315a on the X1 side of the first incomplete thread 315 is the hatched portion shown in FIG. 9 . The axial end surface portion 315a extends radially along a first plane perpendicular to the central axis AX. In FIG. 9 , the axial end surface portion 315a is located on the Z1 side in the circumferential direction of the male thread portion 311. Specifically, the axial end surface portion 315a extends over half the circumference from the Y1 side, through the Z1 side, to the Y2 side. The Y direction is a radial direction perpendicular to (intersects with) the X direction (axial direction), and the Z direction is a radial direction perpendicular to (intersects with) the X and Y directions. The Y1 side is one side of the Y direction, and the Y2 side is the other side of the Y direction. The Z1 side is one side of the Z direction, and the Z2 side is the other side of the Z direction. The radial width is smallest on the Y1 side, gradually increases from the Y1 side to the Z1 side, and reaches its maximum on the Z1 side. Then, the width gradually decreases toward the Y2 side, reaching its minimum on the Y2 side. The radial width on the Z1 side is the same as the width of the complete thread 314 shown in FIG. 9 . In contrast, the separated portion 315b not hatched in FIG. 9 is located on the opposite side of the central axis AX in FIG. 9 . That is, it extends circumferentially from the Y1 side through the Z2 side to the Y2 side over half a circumference. In the present invention, the term "incomplete thread" refers to a "thread portion having an incomplete thread shape formed by the chamfered portion or the chamfered portion of a thread processing tool" (see JIS B 0101).

[0063] Here, assuming a first plane perpendicular to the central axis AX, the hatched axial end surface 315a abuts against the first plane. The separation portion 315b is spaced from the first plane toward the X2 side (the center of the axial direction of the rotating member 31) . When viewed from the X direction, the axial end surface 315a is located on the opposite side of the separation portion 315b from the line L perpendicular to the central axis AX.

[0064] As shown in FIG. 10 , a second incomplete thread 316 is disposed at the end of the male thread portion 311 closest to the X2 side. The axial end surface 316a of the second incomplete thread 316 on the X2 side is the hatched portion shown in FIG. 10 . The axial end surface 316a extends radially along a second plane perpendicular to the central axis AX. In FIG. 10 , the axial end surface 316a is provided on the Z1 side of the circumferential direction of the male thread portion 311. Specifically, the axial end surface 316a extends over half the circumference from the Y2 side through the Z1 side to the Y1 side. The radial width is smallest on the Y2 side, gradually increases from the Y2 side to the Z1 side, and is largest on the Z1 side. Then, the width gradually decreases toward the Y1 side, reaching a minimum at Y1. 10 is located on the opposite side of the axial end surface portion 316a with respect to a straight line L perpendicular to the central axis AX. That is, the separation portion 316b extends circumferentially over half the circumference from the Y2 side through the Z2 side to the Y1 side.

[0065] Here, assuming the second plane perpendicular to the central axis AX, the hatched axial end surface 316a abuts against the second plane. The separation portion 315b shown in Figure 10 is spaced from the second plane toward the X2 side (the axial center of the rotating member 31). When viewed from the X direction, the axial end surface 316a is located on the opposite side of the separation portion 316b with respect to the line L perpendicular to the central axis AX.

[0066] As such, the rotating member 31 has the axial end surface portion 315a and the axial end surface portion 316a at both ends in the X direction. The axial end surface portion 315a and the axial end surface portion 316a are both provided over approximately half the circumference on the same circumferential side, that is, the Z1 side. In other words, in the rotating member 31 according to this embodiment, when viewed from the X direction, the axial end surface portion 315a and the axial end surface portion 316a are provided on the same side, that is, the Z1 side, with respect to a line L perpendicular to the central axis AX.

[0067] Next, a rotating member 31A according to a modified example will be described. Fig. 11 is a side view of the rotating member according to the modified example. Fig. 12 is a schematic view of the rotating member of Fig. 11 as seen from direction A. Fig. 13 is a schematic view of the rotating member of Fig. 11 as seen from direction B.

[0068] In the rotating member 31A according to the modified example, when viewed from the X direction, the axial end surface portion 315Aa and the axial end surface portion 316a are provided on the Z2 side and the Z1 side, which are opposite sides of a straight line L perpendicular to the central axis AX. As shown in FIG. 11 , a first incomplete thread 315A is disposed at the end of the male thread portion 311 closest to the X1 side. The axial end surface portion 315Aa on the X1 side of the first incomplete thread 315A is the hatched portion shown in FIG. 12 . The axial end surface portion 315Aa extends radially along a first plane perpendicular to the central axis AX. In FIG. 12 , the axial end surface portion 315Aa is provided on the Z2 side in the circumferential direction of the male thread portion 311. Specifically, the axial end surface portion 315Aa extends halfway around the circumference from the Y1 side through the Z2 side to the Y2 side. The radial width is smallest on the Y1 side, gradually increases from the Y1 side to the Z2 side, and is largest on the Z2 side. The width then gradually decreases toward the Y2 side, reaching a minimum at the Y2 side. In contrast, the separated portion 315Ab shown in FIG. 12 is located on the opposite side of the axial end surface portion 315Aa with respect to a straight line L perpendicular to the central axis AX. That is, the separated portion 315Ab extends circumferentially from the Y1 side through the Z1 side to the Y2 side over half the circumference.

[0069] Here, assuming a first plane perpendicular to the central axis AX, the hatched axial end surface 315Aa abuts on the first plane. The spaced portion 315Ab shown in Fig. 12 is spaced from the first plane toward the X2 side (the center of the axial direction of the rotating member 31A).

[0070] As shown in Figure 11, a second incomplete thread 316 is disposed at the end of the male thread portion 311 closest to the X2 side. An axial end surface 316a on the X2 side of the second incomplete thread 316 is the hatched portion shown in Figure 13. The axial end surface 316a extends in the radial direction along a second plane perpendicular to the central axis AX. The axial end surface 316a shown in Figure 13 is the same as the axial end surface 316a shown in Figure 10 described above.

[0071] As described above, the rotating member 31A has the axial end surface portion 315Aa and the axial end surface portion 316a at both ends in the X direction. The axial end surface portion 315Aa and the axial end surface portion 316a are provided over approximately half the circumference on the Z2 side and the Z1 side, which are opposite sides in the circumferential direction. In other words, in the rotating member 31A according to the modified example, when viewed from the X direction, the axial end surface portion 315Aa and the axial end surface portion 316a are provided on the Z2 side and the Z1 side, which are opposite sides of the line L perpendicular to the central axis AX.

[0072] As described above, in the vehicle steering device 100 according to this embodiment, the stopper mechanism 3 includes the rotating member 31 having the male thread portion 311 and a pair of cylindrical surface portions (the first cylindrical surface portion 312 and the second cylindrical surface portion 312A), the nut 32 that moves in the X direction (axial direction) relative to the rotating member 31, a pair of annular members (the first annular member 331 and the second annular member 331A) that are inserted into the pair of cylindrical surface portions of the rotating member 31, and the housing 35. The annular members have flat vertical wall portions 332, 332A. The male thread portion 311 of the rotating member 31 has a first incomplete thread 315 disposed at an end on the X1 side (one side in the axial direction) and a second incomplete thread 316 disposed at an end on the X2 side (the other side in the axial direction). The X1-side surface of the first incomplete thread 315 is provided with an axial end face portion 315a and a separation portion 315b. The surface of the second incomplete thread 316 on the X2 side is provided with an axial end surface portion 316a and a separation portion 316b.

[0073] As described above, in the stopper mechanism disclosed in Patent Document 1, because an incomplete thread has less strength than a complete thread, a cylindrical surface portion is provided axially outward and inward of the axial end of the incomplete thread portion to prevent the annular member and leaf spring from contacting the incomplete thread. The annular member is then fitted onto the cylindrical surface portion, and the leaf spring is fitted onto the outer periphery of the annular member. As a result, the stopper mechanism disclosed in Patent Document 1 becomes larger in the axial direction, which may ultimately result in an increased size of the vehicle steering device.

[0074] In contrast, in the stopper mechanism 3 according to this embodiment, the axial end face 315a on the X1 side of the first incomplete thread 315 abuts against the end face on the X2 side of the vertical wall portion 332 of the first annular member 331, and the axial end face 316a on the X2 side of the second incomplete thread 316 abuts against the end face on the X1 side of the vertical wall portion 332A of the second annular member 331A.

[0075] Therefore, as shown in FIG. 4 , in this embodiment, first, when the nut 32 moves toward the X1 side due to the rotation of the rotating member 31 and the axial end face 322 of the nut 32 comes into contact with the vertical wall portion 332 of the first annular member 331, the rotating member 31 is pushed toward the X2 side together with the nut 32, and the rotating member 31 pushed toward the X2 side compresses the vertical wall portion 332A of the second annular member 331A on the X2 side, and the resulting reaction force pushes the axial end face portion 316a of the second incomplete thread 316 back toward the X1 side, but the separation portion 316b does not come into contact with the vertical wall portion 332A. Furthermore, as shown in Figure 4, when the nut 32 moves toward the X2 side due to rotation of the rotating member 31 and the axial end face 323 of the nut 32 abuts against the vertical wall portion 332A of the second annular member 331A, the rotating member 31 is pushed toward the X1 side together with the nut 32, and the rotating member 31 pushed toward the X1 side compresses the vertical wall portion 332 of the first annular member 331 on the X1 side, and the resulting reaction force pushes the axial end face portion 315a of the first incomplete thread 315 back toward the X1 side, but the separation portion 315b does not abut against the vertical wall portion 332.

[0076] To summarize the above, in the stopper mechanism 3 according to this embodiment, when the nut 32 moves toward the X1 side due to rotation of the rotating member 31, the vertical wall portion 332A of the second annular member 331A pushes back the axial end face portion 316a of the second incomplete thread 316 toward the X1 side, but the separating portion 316b does not abut against the vertical wall portion 332A. Also, when the nut 32 moves toward the X2 side due to rotation of the rotating member 31, the vertical wall portion 332 of the first annular member 331 pushes back the axial end face portion 315a of the first incomplete thread 315 toward the X2 side, but the separating portion 315b does not abut against the vertical wall portion 332. In this way, in the stopper mechanism 3 according to this embodiment, the first annular member 331 abuts against the first incomplete thread 315 of the rotating member 31, and the second annular member 331A abuts against the second incomplete thread 316.

[0077] Therefore, compared to the stopper mechanism part of Patent Document 1 in which the annular member and the leaf spring do not abut against the incomplete thread, the stopper mechanism part 3 of this embodiment can be set to have a smaller axial size, and ultimately it is possible to provide a vehicle steering device 100 that is more compact.

[0078] Next, the difference in the oscillation directions shown in FIGS. 8 and 11 will be explained by comparing the rotation member 31 according to the embodiment shown in FIGS. 9 and 10 with the rotation member 31A according to the modified example shown in FIGS. 12 and 13. In the rotation member 31 according to the embodiment shown in FIGS. 9 and 10, when viewed from the X direction, the axial end surface 315a of the first incomplete thread 315 and the axial end surface 316a of the second incomplete thread 316 are located on the same Z1 side with respect to a line L perpendicular to the central axis AX. The oscillation direction R1 shown in FIG. 8 is a clockwise direction (right-handed direction) centered on the center O, which is located in the center of the central axis AX in the X direction, when viewed from the Y1 side. The oscillation direction R2 is a counterclockwise direction (left-handed direction) centered on the center O, when viewed from the Y1 side.

[0079] As described above, as shown in Fig. 4, first, when the nut 32 moves toward the X1 side due to rotation of the rotating member 31 and the axial end face 322 of the nut 32 abuts against the vertical wall portion 332 of the first annular member 331, the rotating member 31 is pushed toward the X2 side together with the nut 32, and the rotating member 31 pushed toward the X2 side compresses the vertical wall portion 332A of the second annular member 331A on the X2 side, and the resulting reaction force pushes the axial end face portion 316a of the second incomplete thread 316 back toward the X1 side. Here, as shown in Fig. 10, because the axial end face portion 316a is located on the Z1 side with respect to the separation portion 316b, the rotating member 31 swings in the swing direction R1 shown in Fig. 8.

[0080] 4, when the nut 32 moves toward the X2 side due to rotation of the rotating member 31 and the axial end face 323 of the nut 32 abuts against the vertical wall portion 332A of the second annular member 331A, the rotating member 31 is pushed toward the X1 side together with the nut 32, and the rotating member 31 pushed toward the X1 side compresses the vertical wall portion 332 of the first annular member 331 on the X1 side, and the resulting reaction force pushes the axial end face portion 315a of the first incomplete thread 315 back toward the X1 side. Here, as shown in FIG. 9, because the axial end face portion 315a is located on the Z1 side with respect to the separation portion 315b, the rotating member 31 swings in the swing direction R2 shown in FIG. 8.

[0081] In this way, in the rotating member 31 according to the embodiment, when the nut 32 moves to the X1 side and when it moves to the X2 side, the swinging direction of the rotating member 31 when viewed from the Y1 side is opposite to each other, so that the load is applied evenly to the first annular member 331 and the second annular member 331A, thereby improving the durability of the first annular member 331 and the second annular member 331A.

[0082] Next, the swing direction of the rotating member 31A according to the modified example will be described. In the rotating member 31A shown in FIGS. 12 and 13 , when viewed from the X direction, the axial end surface 315Aa of the first incomplete thread 315A and the axial end surface 316a of the second incomplete thread 316 are located on the Z2 and Z1 sides, respectively, opposite each other with respect to a line L perpendicular to the central axis AX. The swing direction R1 shown in FIG. 11 is a clockwise direction (right-handed direction) around the center O, which is located in the center of the central axis AX in the X direction, when viewed from the Y1 side of the rotating member 31A. The swing direction R2 is a counterclockwise direction (left-handed direction) around the center O, when viewed from the Y1 side of the rotating member 31A.

[0083] As described above, as shown in Fig. 4, first, when the nut 32 moves toward the X1 side due to rotation of the rotating member 31A and the axial end face 322 of the nut 32 abuts against the vertical wall portion 332 of the first annular member 331, the rotating member 31A is pushed toward the X2 side together with the nut 32, and the rotating member 31A pushed toward the X2 side compresses the vertical wall portion 332A of the second annular member 331A on the X2 side, and the resulting reaction force pushes the axial end face portion 316a of the second incomplete thread 316 back toward the X1 side. Here, as shown in Fig. 13, because the axial end face portion 316a is located on the Z1 side with respect to the separation portion 316b, the rotating member 31A swings in the swing direction R1 shown in Fig. 11.

[0084] 4, when the nut 32 moves toward the X2 side due to rotation of the rotating member 31A and the axial end face 323 of the nut 32 abuts against the vertical wall portion 332A of the second annular member 331A, the rotating member 31A is pushed toward the X1 side together with the nut 32, and the rotating member 31A pushed toward the X1 side compresses the vertical wall portion 332 of the first annular member 331 on the X1 side, and the resulting reaction force pushes the axial end face portion 315Aa of the first incomplete thread 315A back toward the X1 side. Here, as shown in FIG. 12, because the axial end face portion 315Aa is located on the Z2 side with respect to the separation portion 315Ab, the rotating member 31A swings in the swing direction R1 shown in FIG.

[0085] As described above, in the rotating member 31A according to the modified example, the rotating member 31A swings in the swing direction R1 regardless of whether the nut 32 moves toward the X1 side or the X2 side. When the rotating member 31A swings in the swing direction R1, the advantage of the spacing portion 315Ab being located on the Z1 side and the spacing portion 316b being located on the Z2 side is that the rotating member 31A swings more easily. This is explained in detail below. When the nut 32 moves toward the X1 side and the rotating member 31A swings in the swing direction R1, the axial end surface portion 316a moves slightly toward the X1 side relative to the second annular member 331A, and the spacing portion 316b moves slightly toward the X2 side. That is, the spacing portion 316b moves toward the vertical wall portion 332A. Because the spacing portion 316b is located closer to the X1 side than the axial end surface portion 316a, a gap is formed between the spacing portion 316b and the vertical wall portion 332A. Therefore, the separating portion 316b can easily approach the vertical wall portion 332A of the second annular member 331A, and the rotating member 31A can easily swing in the swing direction R1.

[0086] Furthermore, when the nut 32 moves toward the X2 side and the rotating member 31A swings in the swing direction R1, the axial end surface portion 315Aa moves slightly toward the X2 side relative to the first annular member 331, and the separating portion 315Ab moves slightly toward the X1 side. That is, the separating portion 315Ab moves in a direction approaching the vertical wall portion 332. Here, because the separating portion 315Ab is located closer to the X2 side than the axial end surface portion 315Aa, a gap is generated between the separating portion 315Ab and the vertical wall portion 332. Therefore, the separating portion 315Ab can easily approach the vertical wall portion 332 of the first annular member 331, and the rotating member 31A can easily swing in the swing direction R1.

[0087] Second Embodiment A second embodiment will now be described. Fig. 14 is a cross-sectional view of a stopper mechanism according to the second embodiment. Fig. 15 is an enlarged cross-sectional view of the first annular member of Fig. 14.

[0088] The stopper mechanism 3A according to the second embodiment differs from the stopper mechanism 3 according to the first embodiment in that a first annular member 331B is provided.

[0089] 14 and 15 , the first annular member 331B has a vertical wall portion 332 and a tubular portion 333. Each of the vertical wall portion 332 and the tubular portion 333 has a main body portion 338 and a coating layer 339.

[0090] The coating layer 339 is provided on the surface layer of the main body 338. The main body 338 is made of, for example, metal, and the coating layer 339 is made of, for example, resin. The main body 338 has an elastic modulus of, for example, 205 GPa. The coating layer 339 has an elastic modulus of, for example, 650 MPa. Thus, the elastic modulus of the coating layer 339 is smaller than that of the main body 338.

[0091] As described above, in the vehicle steering device according to the second embodiment, the first annular member 331B and the second annular member 331C include a main body 338 and a coating layer 339 provided on the surface of the main body 338. The elastic modulus of the coating layer 339 is smaller than that of the main body 338. This reduces contact noise (interference noise) when the nut 32 contacts the first annular member 331B or the second annular member 331C. Note that a material that reduces the coefficient of friction with the mating material may be selected for the coating layer 339 to prevent the nut from getting caught when it contacts the mating material. Alternatively, grease lubrication may be used instead of the coating layer.

[0092] Third Embodiment A third embodiment will now be described with reference to Fig. 16, which is a cross-sectional view of a stopper mechanism according to the third embodiment.

[0093] The stopper mechanism 3B according to the third embodiment differs from the stopper mechanism 3 according to the first embodiment in a first annular member 331D and a second annular member 331E.

[0094] The first annular member 331 according to the first embodiment has a vertical wall portion 332 and a cylindrical portion 333. In contrast, the first annular member 331D according to the third embodiment further has a protruding portion 336. That is, the first annular member 331D has the vertical wall portion 332, the cylindrical portion 333, and the protruding portion 336. The protruding portion 336 extends in the circumferential direction. The protruding portion 336 extends from the radially outer end of the vertical wall portion 332 toward the X2 side.

[0095] The second annular member 331E has a vertical wall portion 332A, a cylindrical portion 333A, and a protrusion 337. The protrusion 337 extends in the circumferential direction. The protrusion 337 extends from the radially outer end of the vertical wall portion 332A toward the X1 side.

[0096] As such, the first annular member 331D has a protruding portion 336 that protrudes toward the nut side in the X direction (axial direction) and can abut against the nut 32. The second annular member 331E has a protruding portion 337 that protrudes toward the nut side in the X direction (axial direction) and can abut against the nut 32.

[0097] As described above, in the vehicle steering device of the third embodiment, the first annular member 331D and the second annular member 331E each have a protrusion 336 or a protrusion 337 that protrudes toward the nut side in the X direction and can abut against the nut 32.

[0098] Therefore, in the third embodiment, the distance that the nut 32 can move in the X direction is short compared to the first annular member 331 and the second annular member 331A that do not have the protrusion 336 or the protrusion 337 according to the first embodiment. This reduces the limit range of the steering angle of the steered wheels 22, and makes it possible to set the rotatable angle of the steering wheel 10 to a smaller value.

[0099] [Fourth embodiment] A fourth embodiment will be described below with reference to Fig. 17, which is a cross-sectional view of a stopper mechanism according to the fourth embodiment.

[0100] The stopper mechanism 3C according to the fourth embodiment differs from the stopper mechanism 3 according to the first embodiment in a radial wall portion 352c, which will be described in detail below.

[0101] The housing 35A according to the fourth embodiment includes a cylindrical portion 352b (housing main body) and a sealing portion 352g that seals the X1 side of the cylindrical portion 352b. The X1 side end of the housing 35A is sealed by the sealing portion 352g.

[0102] As described above, the housing 35A according to this embodiment has a cylindrical portion 352b (housing main body) that extends circumferentially, and a sealing portion 352g that seals the X1 side of the cylindrical portion 352b.

[0103] In this way, the housing 35A is sealed by the sealing portion 352g, which prevents foreign matter such as dust from entering the inside of the housing 35A. Also, it is possible to prevent oil inside the housing 35A from leaking to the outside.

[0104] Fifth Embodiment A fifth embodiment will now be described with reference to Fig. 18, which is a cross-sectional view of a stopper mechanism according to the fifth embodiment.

[0105] In the stopper mechanism 3D according to the fifth embodiment, a seal member S is provided in the housing 35B. A brief description will be given below. As shown in FIG. 18 , the second housing 352B has a protrusion 352Bd at the end on the X1 side. A recess 354 is provided on the inner circumferential side of the protrusion 352Bd. The recess 354 extends annularly along the circumferential direction. In the cross section shown in FIG. 18 , the recess 354 has a generally trapezoidal shape whose distance in the X direction decreases as it moves radially outward. An annular seal member S is housed inside the recess 354.

[0106] The first annular member 331F also has a vertical wall portion 332 and a tubular portion 333F. The first annular member 331F differs from the first annular member 331 in the tubular portion 333F. Specifically, the distance in the X direction of the tubular portion 333F of the first annular member 331F is greater than the distance in the X direction of the tubular portion 333F of the first annular member 331. The tubular portion 333F seals the opening on the inner circumferential side of the recess 354. An inner circumferential tip S10 of the seal member S abuts against the tubular portion 333F.

[0107] As described above, in the vehicle steering device according to the fifth embodiment, the second housing 352B has the protrusion 352Bd in which the recess 354 is provided, and the annular seal member S is housed in the recess 354. The tip S10 on the inner circumferential side of the seal member S abuts against the tubular portion 333F. A through hole 353 is provided in the radial wall portion 352c of the second housing 352B.

[0108] The seal member S can prevent oil inside the second housing 352B from leaking to the outside. There is also the possibility that foreign matter such as dust may enter the inside of the second housing 352B through the through-hole 353. However, because the tip S10 of the seal member S abuts against the first annular member 331F, it is possible to prevent the entry of such foreign matter.

[0109] 3, 3A, 3B, 3C, 3D Stopper mechanism 4 Steering unit 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 Turning wheel 31, 31A Rotating member 32 Nut 35, 35A, 35B Housing 100 Vehicle steering device 110 Motor 121 Shaft holding member 122 Pin 123 Rotation support member 124 Rotation support member 125, 126 Bearing 127 Sub-housing 128 Torque sensor 310 Male thread 310a Bottom portion 311 Male thread portion 312 First cylindrical surface portion 312A Second cylindrical surface portion 313 Cylindrical surface 314 Complete thread 315, 315A First incomplete thread 315a, 315Aa Axial end face portion 315b, 315Ab Separated portion 316 Second incomplete thread 316a Axial end face portion 316b Separated portion 317 Axial end face 318 Axial end face 319 Female spline 321 Female thread 322 Axial end face 323 Axial end face 324 Outer circumferential surface 325 Protrusion 331 First annular member 331A Second annular member 331B First annular member 331C Second annular member 331D First annular member 331E Second annular member 331F First annular member 332 Vertical wall portion 332A Vertical wall portion 333 Cylindrical portion 333A, 333F Cylindrical portion 334 Corner portion 334A Corner portion 336 Protruding portion 337 Protruding portion 338 Main body portion 339 Coating layer 351 First housing 351a Joining portion 351b Vertical wall portion 351c Cylindrical portion 351d Flange 352 Second housing 352a Joined portion 352b Cylindrical portion (housing main body portion) 352c Radial wall portion 352g Sealing portion 352h Flange 352j Groove portion 352B Second housing 352Bd Protruding portion 353 Through hole 354 Recessed portion BL Bolt H1 First bolt hole H2 Second bolt hole L Straight line R1, R2 Swing direction S Seal member S10 Tip

Claims

1. A steering device for a vehicle in which a steering wheel and steered wheels are mechanically disconnected, comprising a stopper mechanism for restricting the range of a rotation angle of the steering wheel when the steering wheel is rotated, the stopper mechanism comprising: a rotating member having a male thread portion having a male thread including a complete thread and an incomplete thread provided on its outer periphery, and a pair of cylindrical surface portions adjacent to the male thread portion on one and the other axial sides of a central axis and having a cylindrical surface with a diameter smaller than the outer diameter of the male thread portion, the rotating member rotating in a circumferential direction around the central axis in response to the rotation of the steering wheel; a nut having a female thread that meshes with the male thread on its inner periphery and that moves in the axial direction relative to the rotating member as the rotating member rotates; a pair of annular members inserted into each of the pair of cylindrical surface portions of the rotating member and capable of abutting against the nut in the axial direction; and a housing arranged on the outer periphery of the rotating member, the nut, and the pair of annular members, and supporting each of the pair of annular members between the rotating member and the housing. A vehicle steering device, wherein the male thread portion of the rotating member has a first incomplete thread arranged at one axial end and a second incomplete thread arranged at the other axial end, and the complete thread is arranged between the first incomplete thread and the second incomplete thread, one axial surface of the first incomplete thread is provided with an axial end face portion extending along a first plane perpendicular to the central axis and a separated portion spaced apart to the other axial side from the first plane, and the other axial surface of the second incomplete thread is provided with an axial end face portion extending along a second plane perpendicular to the central axis and a separated portion spaced apart to the one axial side from the second plane.

2. A vehicle steering device as described in claim 1, wherein, when the rotating member is viewed from the axial direction, the axial end face portion of the first incomplete thread and the axial end face portion of the second incomplete thread are positioned on the same side of the central axis.

3. A vehicle steering device as described in claim 1, wherein, when the rotating member is viewed from the axial direction, the axial end face portion of the first incomplete thread and the axial end face portion of the second incomplete thread are positioned on opposite sides of the central axis.

4. A vehicle steering device as claimed in any one of claims 1 to 3, wherein at least one of the pair of annular members comprises a main body and a coating layer provided on a surface layer of the main body, and the elastic modulus of the coating layer is smaller than the elastic modulus of the main body.

5. A vehicle steering device according to any one of claims 1 to 3, wherein at least one of the pair of annular members has a protruding portion that protrudes axially towards the nut and is capable of abutting against the nut.

6. A vehicle steering device according to any one of claims 1 to 3, wherein the housing has a cylindrical housing main body portion extending in a circumferential direction, and a sealing portion that seals one axial side of the housing main body portion.

7. A vehicle steering device as claimed in any one of claims 1 to 3, wherein the housing has a cylindrical housing main body extending circumferentially and opening on one axial side, a protrusion disposed at one axial end of the housing main body and having a recess protruding towards the inner periphery and recessed towards the outer periphery, and a seal member housed in the recess, wherein the annular member is disposed on the inner periphery of the recess of the protrusion, and a tip of the inner periphery of the seal member is capable of abutting against the outer periphery of the annular member.

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