Rotation limiting device and steering device

Abstract

To provide a rotation limiting device that can be reduced in size and can prevent noise from being generated at a position other than a rotation limiting position.SOLUTION: A rotation limiting device 2 is provided with: a linear motion member 15 having a female screw portion 17 on an inner peripheral surface and linearly moving in use; and a rotating member 16 having a male screw portion 24 on an outer peripheral surface and rotating in use. The linear motion member 15 has, at positions deviating from a central axis of the linear motion member in a radial direction, a first axial protrusion protruding toward one side in an axial direction and a second axial protrusion 19 protruding toward the other side in the axial direction. The rotating member 16 has: a first radial protrusion 27 protruding radially outward and engageable with the first axial protrusion in a circumferential direction, in a portion protruding from the linear motion member 15 to one side in the axial direction; and a second radial protrusion 28 protruding radially outward and engageable with the second axial protrusion 19 in the circumferential direction, in a portion protruding from the linear motion member 15 to the other side in the axial direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a rotation limiting device and a steering device. [Background technology]

[0002] In a rack-and-pinion steering device, when the steering wheel is turned (turned) to the maximum right or left, the rack end, which is supported and fixed to the end of the rack shaft, hits the housing. In this way, in a rack-and-pinion steering device in which the steering unit and the steering unit are mechanically connected, the number of lock-to-lock rotations of the steering wheel (the number of rotations of the steering wheel when the steering wheel is turned from the maximum right or left to the maximum left or right) is limited by limiting the stroke of the rack shaft that constitutes the steering unit.

[0003] In contrast, in a steer-by-wire steering system, the steering unit and the turning unit are not mechanically connected, so it is not possible to limit the lock-to-lock rotation speed of the steering wheel that constitutes the steering unit by limiting the stroke of the rack shaft that constitutes the turning unit.

[0004] 9 shows a stopper unit 100 for mechanically limiting the lock-to-lock rotation speed of a steering wheel in a steer-by-wire steering device described in Japanese Patent Application Laid-Open No. 2020-69844. The stopper unit 100 includes a first rotating member 101, a housing 102, and a second rotating member 103.

[0005] The first rotating member 101 has a first rotating protrusion 104 that protrudes toward one axial direction on one side surface (the right side surface in FIG. 9). The first rotating member 101 is connected and fixed to the tip end (the end on the other axial direction) of a steering shaft (not shown) so as not to rotate relative to it. In other words, the first rotating member 101 rotates integrally with the steering shaft as the steering wheel is operated.

[0006] The housing 102 has a fixed protrusion 105 that protrudes toward the other axial direction on its other axial side (the left side in FIG. 9), and does not rotate even during use. The steering shaft is supported radially inside the housing 102 so as to be rotatable relative to the housing 102.

[0007] The second rotating member 103 has a cylindrical portion 106 and a second rotating protrusion 107 that protrudes radially outward from one circumferential position on the outer circumferential surface of the cylindrical portion 106. The second rotating member 103 is supported around the steering shaft so as to be rotatable relative to the steering shaft, the first rotating member 101, and the housing 102.

[0008] That is, the steering shaft is inserted through the housing 102 and the second rotating member 103 from one axial side to the other axial side, and the first rotating member 101 is coupled and fixed to the tip of the steering shaft that protrudes from the end face of the second rotating member 103 on the other axial side. In addition, a steering wheel is supported and fixed to the end of the steering shaft on one axial side.

[0009] In a steering device including the stopper unit 100, for example, when the steering wheel is turned to the left (rotated counterclockwise as viewed from the right side in FIG. 9), first, the first rotating member 101 rotates together with the steering shaft from the top to the bottom in FIG. 9. Then, the side surface on one circumferential side of the first rotating protrusion 104 (the lower side surface in FIG. 9) collides with the side surface on the other circumferential side of the other axial side portion of the second rotating protrusion 107 (the upper side surface in FIG. 9).

[0010] When the steering wheel is turned further to the left from this state, the second rotating member 103 rotates together with the steering shaft and the first rotating member 101 from the top to the bottom in FIG. 9. Then, a side surface on one circumferential side of one axial side portion of the second rotating protrusion 107 abuts against a side surface on the other circumferential side of the fixed protrusion 105. This restricts the steering wheel from being turned further to the left. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2020-69844 [Patent Document 2] DE102020126785A1 Summary of the Invention [Problem to be solved by the invention]

[0012] In the stopper unit 100 described in JP 2020-69844 A, the first rotation protrusion 104 of the first rotation member 101, which rotates with the steering wheel, collides with the second rotation protrusion 107 of the second rotation member 103 before the steering wheel rotates to the rotation limit position. This may cause an abnormal noise due to the collision. It may also cause a driver operating the steering wheel to feel uncomfortable.

[0013] DE102020126785A1 discloses the structure of a rotation limiting device equipped with a linearly moving member and a rotating member. In the conventional rotation limiting device described in DE102020126785A1, the linearly moving member presses a plate against the inner surface of the casing in the axial direction, thereby limiting the rotation of the rotating member.

[0014] Because rotation limiting devices with this type of conventional structure easily generate relatively large axial forces of several tens of kN, the strength of the rotation limiting device must be ensured, which makes the device prone to becoming large. Furthermore, rotation limiting devices with conventional structures have a leaf spring between the linear motion member and the plate to prevent the rotating member from getting stuck when the rotation direction is reversed due to static friction between the plate and the inner surface of the casing. This also makes the device prone to becoming large.

[0015] An object of the present disclosure is to provide a rotation limiting device that can be made smaller and that can suppress the generation of abnormal noise at positions other than the rotation limiting position. [Means for solving the problem]

[0016] A rotation limiting device according to one aspect of the present disclosure includes a linearly moving member and a rotating member.

[0017] The linear motion member has a female thread on its inner peripheral surface and moves linearly when in use.

[0018] The rotating member has a male thread portion on its outer circumferential surface that is threadedly engaged with the female thread portion, and rotates when in use.

[0019] The linear motion member has a first axial projection protruding toward one axial side and a second axial projection protruding toward the other axial side at positions radially offset from the central axis thereof.

[0020] The rotating member has, at a portion protruding from the linear moving member to one side in the axial direction, a first radial protrusion that protrudes radially outward and is circumferentially engageable with the first axial protrusion, and, at a portion protruding from the linear moving member to the other side in the axial direction, a second radial protrusion that protrudes radially outward and is circumferentially engageable with the second axial protrusion.

[0021] The rotation limiting device according to one aspect of the present disclosure further includes a rotation stopper member that prevents rotation of the linearly moving member.

[0022] In the rotation limiting device according to one aspect of the present disclosure, the rotation stop member has a hollow shape, and the linearly moving member and the rotating member are disposed inside the rotation stop member.

[0023] The rotation limiting device according to one aspect of the present disclosure further includes a retaining member that prevents the rotating member from slipping out in the axial direction from inside the rotation stopping member.

[0024] In a rotation limiting device according to one aspect of the present disclosure, the rotating member includes a rotating shaft having the male thread portion on its outer peripheral surface, a first stopper member having the first radial protrusion and fixed to one axial end of the rotating shaft, and a second stopper member having the second radial protrusion and fixed to the other axial end of the rotating shaft.

[0025] In a rotation limiting device according to one aspect of the present disclosure, the first stopper member has a first boss portion fixed to one axial end of the rotating shaft, and the first radial protrusion provided on a portion of the outer peripheral surface of the first boss portion. The second stopper member has a second boss portion fixed to the other axial end of the rotary shaft, and the second radial protrusion provided on a part of the outer peripheral surface of the second boss portion.

[0026] A steering device according to one aspect of the present disclosure includes a steering shaft and a rotation limiting device that limits the amount of rotation of the steering shaft to a predetermined value.

[0027] The rotation limiting device is configured by the rotation limiting device according to one aspect of the present disclosure, and the rotating member is fixedly coupled to the steering shaft. [Effects of the Invention]

[0028] According to the rotation limiting device according to one aspect of the present disclosure, it is possible to achieve miniaturization and to suppress the generation of abnormal noise at positions other than the rotation limiting position. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a schematic diagram showing an example of a steer-by-wire steering system equipped with a rotation limiting device according to a first example of an embodiment of the present disclosure. [Figure 2] FIG. 2 is a partial perspective view of a steering device equipped with a rotation limiting device of the first example. [Figure 3] FIG. 3 is a diagram showing a state in which the rotation limiting device of the first example is removed from FIG. [Figure 4] Figures 4(A) to 4(C) show a first example of a rotation limiting device, where Figure 4(A) is a side view, Figure 4(B) is an end view seen from the left side of Figure 4(A), and Figure 4(C) is an end view seen from the right side of Figure 4(A). [Figure 5] FIG. 5 is an exploded perspective view showing the rotation limiting device of the first example. [Figure 6] FIG. 6 is a cross-sectional view taken along line XX in FIG. 4(B). [Figure 7] Figures 7(A) to 7(C) are schematic diagrams showing the linear member removed from the rotation limiting device of the first example, where Figure 7(A) is a side view, Figure 7(B) is an end view seen from the left side of Figure 7(A), and Figure 7(C) is an end view seen from the right side of Figure 7(A). [Figure 8] Figures 8(A) to 8(C) are schematic diagrams showing a rotating member removed from the first example rotation limiting device, where Figure 8(A) is a side view, Figure 8(B) is an end view seen from the left side of Figure 8(A), and Figure 8(C) is an end view seen from the right side of Figure 8(A). [Figure 9] FIG. 9 is an exploded view showing a stopper unit of a conventional structure. DETAILED DESCRIPTION OF THE INVENTION

[0030] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 8(C).

[0031] In this example, a rotation limiting device according to an aspect of the present disclosure is incorporated into a steering unit that constitutes a steering device. However, the rotation limiting device according to an aspect of the present disclosure may be incorporated into any rotating mechanical device and used therein, not limited to steering units that constitute a steering device.

[0032] The overall structure of the steering device 1 will be described below with reference to Fig. 1, and then the rotation limiting device 2 will be described with reference to Figs. 2 to 8. In the following description, the front-rear direction means the front-rear direction of the vehicle.

[0033] [Overall structure of steering device 1] The steering device 1 includes a steering unit 4 having a steering wheel 3, a steering unit 6 that applies a steering angle to a pair of steered wheels 5, and a control unit (ECU) .

[0034] The steering device 1 has a linkless structure in which the steering unit 4 and the steered unit 6 are not mechanically connected to each other but are electrically connected to each other via the control unit 7.

[0035] The steering unit 4 includes a steering column 8, a steering shaft 9, a reaction force applying device 10, and a rotation limiting device 2.

[0036] The steering column 8 has a cylindrical shape and is supported by the vehicle body.

[0037] The steering shaft 9 is rotatably supported on the radially inner side of the steering column 8. The steering wheel 3 is supported and fixed to the rear end of the steering shaft 9.

[0038] The reaction force applying device 10 is connected to the front portion of the steering shaft 9. The reaction force applying device 10 includes a reaction force applying motor and a reducer such as a worm reducer. The reaction force applying device 10 applies the output torque of the reaction force applying motor to the steering shaft 9 after increasing it using the reducer.

[0039] The rotation limiting device 2 is provided between the steering shaft 9 and a portion that does not rotate even when in use, and limits the number of lock-to-lock rotations of the steering wheel 3. In other words, it limits the number of lock-to-lock rotations, which is the number of rotations when the steering wheel 3 is rotated from one rotation limit position to the other rotation limit position.

[0040] In this example, the rotation limiting device 2 is provided between the front end of the steering shaft 9 and a housing 11 of a reaction force applying device 10 that does not rotate even when in use.

[0041] However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation limiting device can be located anywhere between the steering shaft and a fixed portion that does not rotate even when in use. Specifically, the rotation limiting device can be located between the front portion of the steering shaft and the front end of the steering column that does not rotate even when in use. Alternatively, the rotation limiting device can be located closer to the steering wheel, for example, between the rear portion of the steering shaft and the rear end of the steering column.

[0042] The steering unit 4 may further include sensors (not shown), such as a torque sensor and a steering angle sensor, that measure the operation of the steering wheel 3 by the driver.

[0043] The steering unit 6 includes a gear housing 12 supported and fixed to the vehicle body, a steering shaft (not shown), and a steering actuator 13 that linearly drives the steering shaft.

[0044] The steering shaft is composed of a rack shaft, a screw shaft, etc. The steering shaft has its axial direction aligned with the width direction of the vehicle body and is supported inside gear housing 12 so as to be able to move linearly in the axial direction. Base ends of a pair of tie rods 14 are connected to both axial ends of the steering shaft via spherical joints (not shown). A pair of steered wheels 5 are supported at the tip ends of the pair of tie rods 14.

[0045] When the steering shaft is configured as a rack shaft, steering actuator 13 includes a pinion shaft that meshes with the rack shaft, a steering motor, and a reducer. Steering actuator 13 increases the output torque of the steering motor using the reducer and then inputs it to the pinion shaft, driving the pinion shaft to rotate, thereby linearly moving the rack shaft.

[0046] When the steering shaft is configured by a screw shaft, steering actuator 13 includes a nut supported around the screw shaft so as to be rotatable relative to the screw shaft, a steering motor, and a reducer. Steering actuator 13 increases the output torque of the steering motor using the reducer and then inputs it to the nut, which then rotates and drives the nut to linearly move the screw shaft.

[0047] The feed screw mechanism including the screw shaft and the nut can be configured as a sliding screw type feed screw mechanism in which a male threaded portion on the outer peripheral surface of the screw shaft and a female threaded portion on the inner peripheral surface of the nut are directly threaded together. Alternatively, the feed screw mechanism including the screw shaft and the nut can be configured as a ball screw type feed screw mechanism in which a plurality of balls are rollably arranged between an inner diameter side ball screw groove on the outer peripheral surface of the screw shaft and an outer diameter side ball screw groove on the inner peripheral surface of the nut.

[0048] In the steering device 1 of this example, when the driver operates the steering wheel 3, the operation of the steering wheel 3 is measured by a sensor in the steering unit 4, and the measurement results are output to the control unit 7. Various signals indicating the driving situation, such as the steering torque measured by a torque sensor, the steering angle measured by a steering angle sensor, the vehicle speed, the yaw rate, and the acceleration, are input to the control unit 7. The control unit 7 drives the steering actuator 13 provided in the steering unit 6 based on the various signals indicating the driving situation. As a result, the steering axis is displaced in the width direction of the vehicle body, and a pair of tie rods 14 are pushed and pulled, thereby applying a steering angle to the pair of steered wheels 5.

[0049] [Structure of rotation limiting device] The rotation limiting device 2 in this example is provided between the front end of the steering shaft 9 and the housing 11 of the reaction force applying device 10, which does not rotate even when in use, and limits the lock-to-lock rotation speed of the steering wheel 3 by limiting the amount of rotation of the steering shaft 9 to a predetermined value.

[0050] The rotation limiting device 2 includes a linearly moving member 15 and a rotating member 16. The linearly moving member 15 and the rotating member 16 are arranged coaxially.

[0051] In the following description of the rotation limiting device 2, unless otherwise specified, the axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the linear moving member 15. The axial direction, radial direction, and circumferential direction of the linear moving member 15 coincide with the axial direction, radial direction, and circumferential direction of the rotating member 16. Furthermore, one axial side corresponds to the rear side of the vehicle and refers to the right side in Figures 4(A), 5 to 7(A), and 8(A), and the other axial side corresponds to the front side of the vehicle and refers to the left side in Figures 4(A), 5 to 7(A), and 8(A).

[0052] <Linear motion components> The linear motion member 15 has a female thread portion 17 on its inner peripheral surface and moves linearly when in use. The linear motion member 15 is prevented from rotating around its own central axis by a rotation stop member 39, which will be described later.

[0053] In this example, the linear motion member 15 has a cylindrical outer peripheral surface and has a generally annular shape as a whole. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the linear motion member may have a rectangular cylindrical outer peripheral surface.

[0054] The linear motion member 15 has an inner diameter large enough to allow the rotation member 16 to be inserted therethrough. In this example, the linear motion member 15 has an outer diameter large enough to allow it to be inserted inside the rotation stop member 39.

[0055] The linear motion member 15 has a central axis O 15 The first axial projection 18 projects toward one axial side and the second axial projection 19 projects toward the other axial side at positions radially offset from the first axial projection 18.

[0056] In this example, the linear motion member 15 has a first axial protrusion 18 at one circumferential location on the flat end face on one axial side, and a second axial protrusion 19 at one circumferential location on the flat end face on the other axial side.

[0057] In this example, the first axial protrusion 18 and the second axial protrusion 19 have a substantially fan-shaped column, and have a substantially trapezoidal shape when viewed in the radial direction.

[0058] The first axial projection 18 has a flat linear motion side first stopper surface 21 on one circumferential side (right side in FIG. 7(C)). In contrast, the second axial projection 19 has a flat linear motion side second stopper surface 22 on the other circumferential side (left side in FIG. 7(A)). The linear motion side first stopper surface 21 and the linear motion side second stopper surface 22 are aligned with the center axis O of the linear motion member 15. 15 The components are arranged on a virtual plane including the

[0059] The first axial protrusion 18 has a first inclined surface on its side surface on the other circumferential side (the left side surface in FIG. 7(C)), which is inclined in a direction toward one axial side as it approaches one circumferential side. In other words, the first axial protrusion 18 has a tapered shape in which the circumferential width becomes smaller as it approaches the radially outer side. In contrast, the second axial protrusion 19 has a second inclined surface on its side surface on one circumferential side (the right side surface in FIG. 7(A)), which is inclined in a direction toward the other axial side as it approaches the other circumferential side. In other words, the second axial protrusion 19 has a tapered shape in which the circumferential width becomes smaller as it approaches the radially outer side.

[0060] The first axial protrusion 18 and the second axial protrusion 19 may be arranged in positions where their phases are the same in the circumferential direction, or may be arranged in positions where their phases are shifted in the circumferential direction. In this example, the first axial protrusion 18 and the second axial protrusion 19 are arranged in positions where their phases are shifted in the circumferential direction from an inner diameter side engaging portion 23, which will be described later. In the example shown in the figure, the first axial protrusion 18 and the second axial protrusion 19 are arranged in positions where their phases are shifted by 90 degrees from the inner diameter side engaging portion 23 in the circumferential direction. Moreover, the first axial protrusion 18 and the second axial protrusion 19 are arranged in positions where their phases are shifted by 180 degrees from each other.

[0061] The circumferential width of the first axial protrusion 18 and the second axial protrusion 19, i.e., the central axis O of the linear motion member 15 15 The angle θ formed by the ends of the first axial protrusion 18 and the second axial protrusion 19 on both sides in the circumferential direction with respect to the center a is not particularly limited as long as it can ensure strength and rigidity.

[0062] In this example, the linear motion member 15 is configured as a single unit, including the first axial protrusion 18 and the second axial protrusion 19. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the first axial protrusion and the second axial protrusion may be configured separately from a main body portion that is annular and has a female thread portion on its inner circumferential surface, and fixed to the main body portion.

[0063] The linear motion member 15 has a central axis O 15 In order to prevent rotation around the linear motion member 15, the linear motion member 15 has an inner diameter side engagement portion 23 on a part of its outer circumferential surface. In this example, the linear motion member 15 has two inner diameter side engagement portions 23. The two inner diameter side engagement portions 23 are positioned at positions that are 180 degrees out of phase with each other. However, when implementing a rotation limiting device according to one embodiment of the present disclosure, the linear motion member may be provided with only one inner diameter side engagement portion, or may be provided with three or more inner diameter side engagement portions.

[0064] In this example, the inner diameter side engaging portion 23 is configured as a recessed groove that is recessed radially inward from the outer circumferential surface of the linear motion member 15 and extends in the axial direction. The inner diameter side engaging portion 23 has a substantially fan-shaped cross section.

[0065] <Rotating member> The rotating member 16 has, on its outer circumferential surface, a male thread portion 24 that screws into the female thread portion 17, and rotates when in use.

[0066] In this example, the male thread portion 24 provided on the outer peripheral surface of the rotating member 16 and the female thread portion 17 provided on the inner peripheral surface of the linearly moving member 15 are directly threaded together. Therefore, the linearly moving member 15 and the rotating member 16 constitute a slide screw type feed screw mechanism.

[0067] When implementing a rotation limiting device according to an embodiment of the present disclosure, a male ball screw groove, which is a male threaded portion provided on the outer peripheral surface of the rotating member, and a female ball screw groove, which is a female threaded portion provided on the inner peripheral surface of the linear moving member, may be threadedly engaged with each other via balls. In this case, the linear moving member and the rotating member constitute a ball screw type feed screw mechanism.

[0068] In this example, the rotating member 16 is connected and fixed to the front end of the steering shaft 9 so as not to rotate relative to the steering shaft 9. Therefore, the rotating member 16 rotates together with the steering shaft 9 as the steering wheel 3 is operated.

[0069] The rotating member 16 has a female spline portion 25 on its inner peripheral surface and is fitted onto the front end of the steering shaft 9. The female spline portion 25 is spline-engaged with a male spline portion 26 (see FIG. 3) provided on the outer peripheral surface of the front end of the steering shaft 9 so as to be non-rotatable relative to the steering shaft. When implementing a rotation limiting device according to an embodiment of the present disclosure, the rotating member may be engaged with the steering shaft so as to be non-rotatable relative to the steering shaft by other structures such as key engagement or concave-convex fitting.

[0070] The rotating member 16 is inserted into the linear moving member 15. The axial dimension of the rotating member 16 is larger than the axial dimension of the linear moving member 15. One axial side portion of the rotating member 16 protrudes from the linear moving member 15 to one axial side, and the other axial side portion of the rotating member 16 protrudes from the linear moving member 15 to the other axial side.

[0071] The rotating member 16 has, at a portion protruding from the linear moving member 15 to one side in the axial direction, a first radial protrusion 27 that protrudes radially outward and is circumferentially engageable with the first axial protrusion 18. The rotating member 16 has, at a portion protruding from the linear moving member 15 to the other side in the axial direction, a second radial protrusion 28 that protrudes radially outward and is circumferentially engageable with the second axial protrusion 19.

[0072] The rotation limiting device 2 prevents rotation of the rotating member 16 by circumferentially engaging the first axial protrusion 18 with the first radial protrusion 27, thereby preventing the steering wheel 3 from being rotated further in the other circumferential direction. In addition, the rotation limiting device 2 prevents rotation of the rotating member 16 by circumferentially engaging the second axial protrusion 19 with the second radial protrusion 28, thereby preventing the steering wheel 3 from being rotated further in the one circumferential direction.

[0073] The rotation limiting device 2 of this example can set the number of lock-to-lock rotations of the steering wheel, which is the number of rotations that the steering wheel can rotate from one rotation limiting position where the first axial protrusion 18 and the first radial protrusion 27 are circumferentially engaged to the other rotation limiting position where the second axial protrusion 19 and the second radial protrusion 28 are circumferentially engaged, to, for example, 3 rotations, or 1080 degrees in rotation angle (±540 degrees from the neutral position). However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the number of lock-to-lock rotations of the steering wheel is not limited to 3 rotations, and can be set to a desired number of rotations, such as 2 rotations, 2.5 rotations, or 4 rotations, by adjusting the lead and axial dimension of the female thread portion and the male thread portion, and the axial height of the first axial protrusion and the second axial protrusion, etc.

[0074] In this example, the rotating member 16 is composed of a rotating shaft 29, a first stopper member 30, and a second stopper member 31. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotating member may be composed as a single unit.

[0075] The rotating shaft 29 has a substantially cylindrical shape. The rotating shaft 29 has a male thread portion 24 on its outer peripheral surface. In this example, the rotating shaft 29 has the male thread portion 24 at the axially intermediate portion of its outer peripheral surface. The inner peripheral surface of the rotating shaft 29 is provided with a female spline portion 25 over the entire axial length.

[0076] The rotary shaft 29 has fitting shaft portions 32a and 32b at both axial ends. The fitting shaft portions 32a and 32b have an outer diameter smaller than the outer diameter of the male thread portion 24.

[0077] In this example, the outer peripheral surfaces of the fitting shaft portions 32a, 32b are configured with male serration portions in which a plurality of male serration teeth are arranged at equal intervals in the circumferential direction.

[0078] The first stopper member 30 has a first boss portion 33 and a first radial projection 27. The first stopper member 30 is configured in a substantially six-shape as a whole.

[0079] The first boss portion 33 has a cylindrical outer peripheral surface, and is fixed to the fitting shaft portion 32a of the rotary shaft 29 so as not to be rotatable relative to the fitting shaft portion 32a.

[0080] The first boss portion 33 has an engagement hole 34 in its radial center, through which the fitting shaft portion 32a can be inserted in the axial direction. In this example, the engagement hole 34 is configured as a serration hole. In other words, the inner peripheral surface of the first boss portion 33 is configured as a female serration portion in which a plurality of female serration teeth are arranged at equal intervals in the circumferential direction. The first boss portion 33 is fixed to the fitting shaft portion 32a so as not to rotate relative to it by press-fitting the fitting shaft portion 32a into the engagement hole 34 and by serration-engaging the female serration portion with the male serration portion.

[0081] The thickness of the first boss portion 33 in the axial direction is smaller than the axial dimension of the fitting shaft portion 32a.

[0082] The first radial protrusion 27 is provided on a portion of the outer circumferential surface of the first boss portion 33 in the circumferential direction, and protrudes radially outward. The outer circumferential surface of the first radial protrusion 27 is configured in a partially cylindrical shape. The diameter of an imaginary circle passing through the outer circumferential surface of the first radial protrusion 27 is approximately the same as the outer diameter of the linear motion member 15. The first radial protrusion 27 has a tapered shape. One circumferential side surface of the first radial protrusion 27 (the left side surface in FIG. 8(C)) is smoothly connected to the outer circumferential surface of the first boss portion 33.

[0083] The first radial projection 27 has a flat rotation-side first stopper surface 35 on the other circumferential side (the right side in FIG. 8(C)). The rotation-side first stopper surface 35 comes into surface contact with the linear-side first stopper surface 21 when the linear-moving member 15 moves relative to the rotating member 16 on one side in the axial direction and reaches the stroke end. In this example, the rotation-side first stopper surface 35 is in surface contact with the central axis O of the rotating member 16. 16 The components are arranged on a virtual plane including the

[0084] The second stopper member 31 has a second boss portion 36 and a second radial projection 28. The second stopper member 31 is configured in a substantially six-shape as a whole.

[0085] The second boss portion 36 has a cylindrical outer peripheral surface, and is fixed to the fitting shaft portion 32b of the rotary shaft 29 so as not to be rotatable relative to the fitting shaft portion 32b.

[0086] The second boss portion 36 has an engagement hole 37 in its radial center, through which the fitting shaft portion 32b can be inserted in the axial direction. In this example, the engagement hole 37 is configured as a serration hole. In other words, the inner peripheral surface of the second boss portion 36 is configured as a female serration portion in which a plurality of female serration teeth are arranged at equal intervals in the circumferential direction. The second boss portion 36 is fixed to the fitting shaft portion 32b so as not to rotate relative to it by press-fitting the fitting shaft portion 32b into the engagement hole 37 and by serration-engaging the female serration portion with the male serration portion.

[0087] The second radial protrusion 28 is provided on a portion of the outer circumferential surface of the second boss portion 36 in the circumferential direction, and protrudes radially outward. The outer circumferential surface of the second radial protrusion 28 is configured in a partially cylindrical shape. The diameter of an imaginary circle passing through the outer circumferential surface of the second radial protrusion 28 is approximately the same as the outer diameter of the linear motion member 15. The second radial protrusion 28 has a tapered shape. The other circumferential side surface of the second radial protrusion 28 (the left side surface in FIG. 8(B)) is smoothly connected to the outer circumferential surface of the second boss portion 36.

[0088] The second radial projection 28 has a flat rotation-side second stopper surface 38 on one circumferential side (the right side in FIG. 8(B)). The rotation-side second stopper surface 38 comes into surface contact with the linear-side second stopper surface 22 when the linear-moving member 15 moves relative to the rotating member 16 on the other axial side and reaches the stroke end. In this example, the rotation-side second stopper surface 38 is in a plane perpendicular to the central axis O of the rotating member 16. 16 The components are arranged on a virtual plane including the

[0089] In this example, the second stopper member 31 is the same part as the first stopper member 30, having the same shape and size, and is fixed in the opposite axial direction to the rotation shaft 29. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the first stopper member and the second stopper member may have different configurations.

[0090] In this example, the rotating shaft 29 and the first and second stopper members 30 and 31 are fixed to each other by serration fitting so as to be unable to rotate relative to each other. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotating shaft and the first and second stopper members may be fixed to each other by other structures such as concave-convex fitting (non-circular fitting), screw fastening, etc., rather than serration fitting, as long as they are fixed to each other so as to be unable to rotate relative to each other.

[0091] The circumferential width of the first radial protrusion 27 and the second radial protrusion 28, i.e., the central axis O of the rotating member 16 16The angle θ formed by the ends on both circumferential sides of the tip portions of the first radial protrusion 27 and the second radial protrusion 28, including the rotation-side first stopper surface 35 and the rotation-side second stopper surface 38, is r is not particularly limited as long as it can ensure strength and rigidity.

[0092] <Rotation stopper> The rotation limiting device 2 of this example further includes a rotation stopper member 39 that prevents the linearly moving member 15 from rotating, i.e., co-rotating.

[0093] The rotation stop member 39 is fixed to a fixed portion that does not rotate even during use. In this example, the rotation stop member 39 is fixed to the front side portion of the housing 11 that constitutes the reaction force applying device 10. The rotation stop member 39 is disposed coaxially with the linearly moving member 15 and the rotating member 16.

[0094] In this example, the rotation stop member 39 has a hollow shape. Specifically, the rotation stop member 39 has a hollow cylindrical shape. The linear motion member 15 and the rotation member 16 are disposed inside the rotation stop member 39.

[0095] The rotation stop member 39 has a cylindrical inner peripheral surface, and has an inner diameter slightly larger than the outer diameter of the linear motion member 15. Therefore, the linear motion member 15 is disposed inside the rotation stop member 39 without any rattle.

[0096] The rotation stop member 39 has an outer diameter side engaging portion 40 on a part of its inner circumferential surface in order to prevent rotation of the linear motion member 15. The outer diameter side engaging portion 40 engages in the circumferential direction with the inner diameter side engaging portion 23 provided on the linear motion member 15 to prevent rotation of the linear motion member 15.

[0097] In this example, the outer diameter side engaging portion 40 engages with the inner diameter side engaging portion 23 so as to prevent the linear motion member 15 from rotating relative to the rotation stop member 39 but to allow relative displacement in the axial direction.

[0098] In this example, the outer diameter side engaging portion 40 and the inner diameter side engaging portion 23 are directly engaged, but when implementing a rotation limiting device according to one embodiment of the present disclosure, in order to ensure sliding properties while suppressing the generation of collision noise, the outer diameter side engaging portion and / or the inner diameter side engaging portion may be covered with a resin coating (sleeve) or the like, and the outer diameter side engaging portion and the inner diameter side engaging portion may be indirectly engaged.

[0099] In this example, the rotation stop member 39 has two outer diameter side engagement portions 40, the same number as the inner diameter side engagement portions 23. The two outer diameter side engagement portions 40 are positioned at positions that are 180 degrees out of phase with each other. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation stop member may be provided with only one outer diameter side engagement portion, or three or more outer diameter side engagement portions.

[0100] In this example, the outer diameter side engaging portion 40 is configured as a protrusion that protrudes radially inward from the inner circumferential surface of the rotation stop member 39 and extends in the axial direction. The outer diameter side engaging portion 40 has a substantially fan-shaped end face.

[0101] When implementing a rotation limiting device according to one embodiment of the present disclosure, the inner diameter side engaging portion may be composed of a protrusion protruding radially outward from the outer peripheral surface of the linear-acting member, and the outer diameter side engaging portion may be composed of a recessed groove recessed radially outward from the inner peripheral surface of the rotation stop member.

[0102] In this example, the rotation stop member 39 has a bolt insertion hole 41 for inserting a bolt (not shown) used for fixing the rotation stop member 39 to the front side of the housing 11 that constitutes the reaction force application device 10.

[0103] The bolt insertion hole 41 is composed of a notch 42 that opens on the outer surface and the end surface on the other axial side of the rotation stop member 39, and a through hole 43 formed in a portion of the rotation stop member 39 that is in phase with the notch 42 in the circumferential direction.

[0104] The cutout 42 has a partially cylindrical cross section and a concave cylindrical inner surface. The through hole 43 is provided at one axial end of the rotation stop member 39, which corresponds to the axial bottom of the cutout 42.

[0105] In this example, the rotation stop member 39 has three bolt insertion holes 41. The three bolt insertion holes 41 are arranged at equal intervals in the circumferential direction. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation stop member may be provided with only two bolt insertion holes, or may be provided with three or more bolt insertion holes.

[0106] In this example, the rotation stop member 39 is configured as a single unit, including the outer diameter side engagement portion 40. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, an outer diameter side engagement portion configured separately from the main body portion may be fixed to a ring-shaped main body portion having bolt insertion holes on the outer circumferential surface.

[0107] The rotation stop member 39 is fixed to the front side of the housing 11 constituting the reaction force applying device 10 by using a bolt (not shown) that is axially inserted through the bolt insertion hole 41. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation stop member may be provided integrally with a fixed part that does not rotate even during use, such as the housing constituting the reaction force applying device.

[0108] <Prevention member> As shown in FIGS. 5 and 6, the rotation limiting device 2 of this example further includes a retaining member 44 that prevents the rotating member 16 from slipping out from inside the rotation stopping member 39 in the axial direction.

[0109] The retaining member 44 prevents the rotating member 16 from slipping out from the inside of the rotation preventing member 39 to the other side in the axial direction.

[0110] The anti-slip member 44 is clamped between the end face on one axial side of the threaded portion 24 of the rotating shaft 29 and the side face on the other axial side of the boss portion 33 of the first stopper member 30, and is fixed to the rotating member 16.

[0111] The retaining member 44 has a circular disk shape. The inner diameter of the retaining member 44 is larger than the outer diameter of the fitting shaft portion 32a of the rotating shaft 29 and smaller than the outer diameter of the male thread portion 24 of the rotating shaft 29. The outer diameter of the retaining member 44 is smaller than the diameter of an imaginary circle passing through the inner circumferential surface of the first axial protrusion 18 and larger than the diameter of an imaginary circle passing through the inner circumferential surface of the outer diameter side engaging portion 40 of the rotation preventing member 39.

[0112] The anti-slip member 44 prevents the rotating member 16, to which the anti-slip member 44 is fixed, from slipping out from the inside of the anti-slip member 39 to the other axial side by contacting (sliding) the side surface facing the other axial side with the end surface on one axial side of the outer diameter side engagement portion 40 of the anti-slip member 39.

[0113] When implementing a rotation limiting device according to one embodiment of the present disclosure, if the rotating member is prevented from coming loose in the axial direction from a rotating axis such as a steering shaft by other structures such as a set screw, the anti-slip member can be omitted from the rotation limiting device.

[0114] The rotation limiting device 2 of this example is suitable for limiting the rotation speed of the steering wheel 3 in an emergency when the rotation speed of the steering wheel 3 exceeds the normal rotation range. In the normal rotation range of the steering wheel 3, the rotation speed of the steering wheel 3 is softly limited by soft end stop control that adjusts the magnitude of the reaction force applied from the reaction force applying device 10 to the steering shaft 9. However, it is also possible to limit the rotation speed of the steering wheel only by the rotation limiting device without using soft end stop control.

[0115] According to the rotation limiting device 2 of this example, it is possible to achieve a reduction in size and to suppress the generation of abnormal noise at positions other than the rotation limiting position.

[0116] The rotation limiting device 2 of this example limits the rotation of the rotating member 16 by circumferentially engaging the first axial protrusion 18 and the second axial protrusion 19 provided on the linearly moving member 15 with the first radial protrusion 27 and the second radial protrusion 28 provided on the rotating member 16. Therefore, compared to the conventional structure described in DE102020126785A1, which limits the rotation of the rotating member by axial force, there is no need to ensure the strength of the rotation limiting device 2. This allows for a reduction in the size of the rotation limiting device 2. Furthermore, the number of parts can be reduced, simplifying the structure of the rotation limiting device 2 and simplifying the assembly work.

[0117] In the rotation limiting device 2 of this example, at one rotation limiting position, the first axial protrusion 18 and the first radial protrusion 27 are engaged in the circumferential direction, and at the other rotation limiting position, the second axial protrusion 19 and the second radial protrusion 28 are engaged in the circumferential direction, but the linear moving member 15 and the rotating member 16 do not abut at any position other than these rotation limiting positions, so that it is possible to suppress the generation of abnormal noise at positions other than the rotation limiting positions. It is also possible to prevent the driver operating the steering wheel 3 from feeling uncomfortable.

[0118] In this example, the rotation stop member 39 for preventing rotation of the linearly moving member 15 is hollow, and the linearly moving member 15 and the rotating member 16 are disposed inside the rotation stop member 39, improving the ease of handling of the rotation limiting device 2. In addition, the ease of work involved in fixing the rotation limiting device 2 to another member can be improved.

[0119] In this example, the rotating member 16 is composed of a rotating shaft 29 having a male thread portion 24 on its outer peripheral surface, a first stopper member 30 having a first radial protrusion 27, and a second stopper member 31 having a second radial protrusion 28. This reduces the processing cost compared to when the rotating member 16 is integrally constructed. Furthermore, the rotating shaft 29, the first stopper member 30, and the second radial protrusion 28 can be made of different materials, improving the design flexibility of the rotating member 16. Furthermore, the lock-to-lock rotation speed of the steering wheel 3 can be easily changed simply by changing the rotating shaft 29, improving the design flexibility. In this example, the first stopper member 30 and the second stopper member 31 are the same component, which also reduces the cost of the rotating member 16.

[0120] In this example, when the first axial protrusion 18 and the first radial protrusion 27 engage in the circumferential direction, the linear-side first stopper surface 21 and the rotation-side first stopper surface 35 come into surface contact, thereby preventing damage to the first axial protrusion 18 and the first radial protrusion 27. Furthermore, when the second axial protrusion 19 and the second radial protrusion 28 engage in the circumferential direction, the linear-side second stopper surface 22 and the rotation-side second stopper surface 38 come into surface contact, thereby preventing damage to the second axial protrusion 19 and the second radial protrusion 28.

[0121] The rotation limiting device 2 of this example is equipped with a retaining member 44 that prevents the rotating member 16 from slipping out in the axial direction from the inside of the rotation stopper member 39. Therefore, there is no need to process the steering shaft 9 in order to prevent the rotating member 16 from slipping out in the axial direction from the front end of the steering shaft 9. Therefore, the rotation limiting device 2 of this example can be assembled to an existing steering shaft 9.

[0122] The rotation limiting device 2 in this example can be retrofitted to the front side of the housing 11 that constitutes the reaction force applying device 10 after the reaction force applying device 10 has been broken in, thereby improving the workability of the assembly work of the steering device 1. [Explanation of symbols]

[0123] 1 Steering device 2. Rotation limiter 3 Steering wheel 4 Steering unit 5 steering wheel 6. Steering unit 7. Control Unit 8. Steering column 9. Steering shaft 10. Reaction force application device 11. Housing 12 Gear housing 13 Steering actuator 14 tie rod 15 Linear motion members 16 Rotating member 17 Female thread 18 1st axial protrusion 19 2nd axial protrusion 21 First stopper surface on the linear side 22 Second stopper surface on the linear side 23 Inner diameter side engagement portion 24 Male thread 25 Female spline part 26 Male spline part 27 First radial protrusion 28 Second radial protrusion 29 Rotational Axis 30 First stopper member 31 second stopper member 32a, 32b mating shaft part 33 First Boss Section 34 Engagement hole 35 Rotation side first stopper surface 36 Second Boss Section 37 Engagement hole 38 Rotation side second stopper surface 39 Rotation stopper 40 Outer diameter side engagement part 41 Bolt insertion hole 42 Notch 43 Through hole 44 Anti-slip member 100 Stopper unit 101 first rotating member 102 Housing 103 Second rotating member 104 First rotating protrusion 105 Fixed protrusion 106 Cylindrical part 107 Second rotating protrusion

Claims

1. a linear motion member having a female thread portion on its inner circumferential surface and moving linearly when in use; a rotating member having a male thread portion on its outer circumferential surface that screws into the female thread portion and that rotates during use; Equipped with the linear motion member has a first axial projection protruding toward one axial side and a second axial projection protruding toward the other axial side at positions radially offset from a central axis thereof, the rotating member has, at a portion protruding from the linear moving member to one axial side, a first radial protrusion that protrudes radially outward and is circumferentially engageable with the first axial protrusion, and, at a portion protruding from the linear moving member to the other axial side, a second radial protrusion that protrudes radially outward and is circumferentially engageable with the second axial protrusion; Rotation limiter.

2. The rotation limiting device according to claim 1 , further comprising a rotation stopper member that prevents rotation of the linearly moving member.

3. The rotation stop member has a hollow shape, The linear motion member and the rotation member are disposed inside the rotation stop member. The rotation limiting device of claim 2 .

4. 4. The rotation restricting device according to claim 3, further comprising a stopper member that prevents the rotating member from slipping out in the axial direction from inside the rotation restricting member.

5. 2. The rotation limiting device according to claim 1, wherein the rotating member comprises: a rotating shaft having the male thread portion on an outer peripheral surface; a first stopper member having the first radial protrusion and fixed to an end portion on one axial side of the rotating shaft; and a second stopper member having the second radial protrusion and fixed to an end portion on the other axial side of the rotating shaft.

6. the first stopper member has a first boss portion fixed to one axial end of the rotary shaft, and the first radial protrusion provided on a part of an outer peripheral surface of the first boss portion, the second stopper member has a second boss portion fixed to the other axial end of the rotary shaft, and the second radial protrusion provided on a part of an outer peripheral surface of the second boss portion.

6. The rotation limiting device of claim 5.

7. a steering shaft; and a rotation limiting device that limits the amount of rotation of the steering shaft to a predetermined value; The rotation limiting device is configured by the rotation limiting device according to any one of claims 1 to 6, The rotating member is fixedly coupled to the steering shaft. Steering device.

Images