Rotation limiting device, steering unit, and steering device

Abstract

To provide a rotation limiting device which enables improvement of work efficiency of an assembly process of a steering device.SOLUTION: A rotation limiting device 2 includes: a rotation side stopper 15 which is fixed to a front end of a steering shaft 9 in a manner that prevents relative rotation; and a stationary side stopper 16 provided at a position, which is offset in a radial direction from a center axis of the steering shaft 9, of a reaction force application device 10 and protruding forward. The rotation side stopper 15 has: a clamp part 17 serving as a fixed part which is detachably fixed to the front end of the steering shaft 9; and a radial projection part 18 which protrudes from an outer peripheral surface of the clamp part 17 in the radial direction and may engage with the stationary side stopper 16 in a circumferential direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a rotation limiting device, a steering unit, 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] International Publication No. 2021 / 160546 discloses the structure of a steer-by-wire steering device equipped with a rotation limiting device for mechanically limiting the number of lock-to-lock rotations of the steering wheel.

[0005] The conventional rotation limiting device described in WO 2021 / 160546 is composed of a rotation stopper fixed to the front side of the steering shaft and a stationary stopper provided in a housing fixed to the front end of the steering column. When the steering wheel is operated, the rotation stopper rotates integrally with the steering shaft and engages with the stationary stopper in the circumferential direction, thereby preventing further rotation of the steering wheel. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2021 / 160546 Brochure Summary of the Invention [Problem to be solved by the invention]

[0007] In the steering device of the conventional structure described in International Publication No. 2021 / 160546, a rotation limiting device is arranged between the steering column and a reaction force applying device for applying a reaction force to the steering shaft.

[0008] Therefore, during the assembly process of the steering device, when the reaction force applying device is broken in, the rotation of the steering shaft is limited by the rotation limiting device, which tends to reduce work efficiency.

[0009] An object of the present disclosure is to provide a rotation limiting device that can improve the work efficiency of the steering device assembly process. [Means for solving the problem]

[0010] A rotation limiting device according to one aspect of the present disclosure includes a rotation-side stopper and a stationary-side stopper.

[0011] The rotation-side stopper is fixed to the front end of the steering shaft so as not to be rotatable relative to the steering shaft.

[0012] The stationary stopper is a reaction force applying device that applies a reaction force to the steering shaft, and is provided at a position radially offset from the central axis of the steering shaft, and protrudes forward.

[0013] The rotating side stopper has a fixed portion that is removably fixed to the front end of the steering shaft, and a radial protrusion that protrudes radially from the outer peripheral surface of the fixed portion and is circumferentially engageable with the stationary side stopper.

[0014] In the rotation limiting device according to one aspect of the present disclosure, the stationary-side stopper is provided at an outer end of the reaction force applying device in the radial direction of the steering shaft.

[0015] In the rotation limiting device according to one aspect of the present disclosure, the fixing portion is a clamp portion that is reduced in diameter by tightening a fastening member and is fixed to the front end portion of the steering shaft.

[0016] In a rotation limiting device according to one embodiment of the present disclosure, the clamp portion has an insertion hole into which the front end of the steering shaft can be inserted, a discontinuous portion provided at one location in the circumferential direction, a pair of flange portions arranged on either side of the discontinuous portion and provided with mounting holes into which the fastening member can be inserted, and a partially cylindrical connecting portion connecting the pair of flange portions.

[0017] In the rotation limiting device according to one aspect of the present disclosure, the mounting hole and the radial protrusion are disposed at the same position in the front-rear direction.

[0018] In one aspect of the rotation limiting device of the present disclosure, the rotation side stopper includes the central axis of the steering shaft, and the product of the weight and the distance from the center of gravity to the central axis of the steering shaft is equal between one side portion and the other side portion arranged on either side of an imaginary plane perpendicular to the protruding direction of the radial protrusion. Alternatively, the rotation side stopper includes the central axis of the steering shaft, and the product of the weight and the distance from the center of gravity to the central axis of the steering shaft differs between one side portion and the other side portion arranged on either side of an imaginary plane perpendicular to the protruding direction of the radial protrusion. When implementing a rotation limiting device according to one aspect of the present disclosure, if the fixing portion is the clamp portion having the insertion hole and the mounting hole, the central axis of the steering shaft and the central axis of the insertion hole coincide, and the imaginary plane includes the central axis of the insertion hole and is arranged parallel to the central axis of the mounting hole.

[0019] A steering unit according to one aspect of the present disclosure includes a steering shaft, a reaction force applying device, and a rotation limiting device that limits the amount of rotation of the steering shaft to a predetermined value.

[0020] In the steering unit according to one aspect of the present disclosure, the rotation limiting device is configured by the rotation limiting device according to one aspect of the present disclosure.

[0021] A steering device according to one aspect of the present disclosure includes a steering unit, a turning unit that applies a steering angle to a steered wheel, and a control unit.

[0022] The steering unit and the steered unit are not mechanically connected to each other, but are electrically connected to each other via the control unit.

[0023] In a steering device according to one aspect of the present disclosure, the steering unit is configured by the steering unit according to one aspect of the present disclosure. [Effects of the Invention]

[0024] According to the rotation limiting device according to one aspect of the present disclosure, the work efficiency of the assembly process of the steering device can be improved. [Brief explanation of the drawings]

[0025] [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 an end view, seen from the front, of a steering unit of a steering device equipped with a rotation limiting device of the first example. [Figure 3] FIG. 3 is a partial perspective view of a steering unit of a steering device equipped with a rotation limiting device of the first example. [Figure 4] FIG. 4 is an exploded perspective view of FIG. [Figure 5] FIG. 5 is a front view showing the rotation-side stopper that constitutes the rotation limiting device of the first example. [Figure 6] Figures 6(A) to 6(C) are figures corresponding to Figure 2, where Figure 6(A) is a figure showing the neutral state of the steering wheel, Figure 6(B) is a figure showing the state where the steering wheel has been rotated to the maximum to the left, and Figure 6(C) is a figure showing the state where the steering wheel has been rotated to the maximum to the right. DETAILED DESCRIPTION OF THE INVENTION

[0026] [Example 1] A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 6(C).

[0027] This example is an example in which a rotation limiting device according to one aspect of the present disclosure is applied to a steer-by-wire steering device.

[0028] Below, the overall structure of the steering device 1 will be described with reference to Fig. 1, and then the rotation limiting device 2 will be described with reference to Figs. 2 to 6(C). In the following description, the front-rear direction means the front-rear direction of the vehicle. The front-rear direction of the vehicle roughly coincides with the axial direction of the steering shaft 9. In other words, the rear side refers to the end side of both axial ends of the steering shaft 9 where the steering wheel 3 is supported and fixed, and the front side refers to the end side of both axial ends of the steering shaft 9 opposite the end side where the steering wheel 3 is supported and fixed.

[0029] [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) .

[0030] 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.

[0031] 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.

[0032] The steering column 8 has a cylindrical shape and is supported by the vehicle body.

[0033] 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.

[0034] 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.

[0035] The rotation limiting device 2 limits the lock-to-lock rotation speed of the steering wheel 3. In other words, it limits the lock-to-lock rotation speed, which is the number of rotations when the steering wheel 3 is rotated from one rotation limit position to the other rotation limit position.

[0036] The rotation limiting device 2 is provided between the front end of the steering shaft 9 and the reaction force applying device 10, which does not rotate even when in use.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] [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 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.

[0045] The rotation limiting device 2 includes a rotation side stopper 15 and a stationary side stopper 16 .

[0046] The rotation-side stopper 15 is fixed to the front end of the steering shaft 9 so as to be unable to rotate relative to the steering shaft 9. In other words, the rotation-side stopper 15 is fixed to a portion of the steering shaft 9 that protrudes forward from the housing 11 of the reaction force applying device 10.

[0047] The stationary stopper 16 is provided in the reaction force applying device 10 at a position radially offset from the central axis of the steering shaft 9, and protrudes forward.

[0048] The rotation limiting device 2 prevents further rotation of the steering wheel 3 by engaging the rotating side stopper 15, which rotates integrally with the steering shaft 9, with the stationary side stopper 16 in the circumferential direction as the steering wheel 3 is operated.

[0049] With respect to the rotation limiting device 2, the axial direction, circumferential direction, and radial direction refer to the axial direction, circumferential direction, and radial direction with respect to the steering shaft 9, unless otherwise specified.

[0050] <Rotation side stopper> The rotation-side stopper 15 includes a clamp portion 17, which is a fixed portion that is detachably fixed to the front end portion of the steering shaft 9, and a radial protrusion portion 18 that protrudes radially from the outer circumferential surface of the clamp portion 17 and is circumferentially engageable with the stationary-side stopper 16. The clamp portion 17 is reduced in diameter by tightening a fastening member 26, which will be described later, and is fixed to the front end portion of the steering shaft 9.

[0051] When implementing a rotation limiting device according to an embodiment of the present disclosure, the fixing portion constituting the rotation stopper is not limited to a clamp portion having a diameter-reducing configuration as long as it has a structure that allows it to be detachably fixed to the front end of the steering shaft. The fixing portion may be detachably fixed to the front end of the steering shaft using an O-ring, a cam bolt, or the like.

[0052] In the present example, the rotation-side stopper 15 is integrally formed with the clamp portion 17 and the radial protrusion 18. The rotation-side stopper 15 is made of a metal material by, for example, forging and cutting. When implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation-side stopper may be formed by fixing a radial protrusion separate from a fixed portion (clamp portion) to the fixed portion.

[0053] In this example, clamp portion 17 has a substantially U-shaped end face and is configured to be elastically contractible. When implementing a rotation limiting device according to an embodiment of the present disclosure, the clamp portion may have any other shape as long as it is configured to be contractible by tightening with a fastening member.

[0054] The clamp portion 17 has an insertion hole 19 into which the front end of the steering shaft 9 can be inserted, a discontinuous portion 20 provided at one location in the circumferential direction, a pair of flange portions 22a, 22b arranged on both sides of the discontinuous portion 20 and provided with mounting holes 21a, 21b into which a fastening member 26 can be inserted, and a partially cylindrical connecting portion 23 connecting the pair of flange portions 22a, 22b. The connecting portion 23 is arranged on the opposite side of the discontinuous portion 20 in the radial direction. When the front end of the steering shaft 9 is inserted into the insertion hole 19, the central axis of the steering shaft 9 and the central axis O of the insertion hole 19 are aligned. 19 is consistent with

[0055] In this example, the clamp portion 17 is formed so as to have a shape that is substantially parallel to the central axis O of the insertion hole 19, except for the shape of the mounting holes 21a and 21b. 19 and has a symmetrical shape with respect to a first imaginary plane α passing through the center position of the discontinuous portion 20 in the width direction.

[0056] The insertion holes 19 are open to both axial end faces of the clamp portion 17. That is, the insertion holes 19 are through holes that pass through the clamp portion 17 in the axial direction.

[0057] In this example, the insertion hole 19 is configured as a spline hole. In other words, a female spline portion 24 having a plurality of female spline teeth arranged at equal intervals in the circumferential direction is provided on the inner peripheral surface of the clamp portion 17, which is configured by the radially inner surfaces of the pair of flange portions 22a, 22b and the inner peripheral surface of the connecting portion 23. The female spline portion 24 is spline-engaged with a male spline portion 25 (see FIG. 4) provided on the outer peripheral surface of the front end of the steering shaft 9 so as to prevent relative rotation. When implementing a rotation limiting device according to an embodiment of the present disclosure, the rotation-side stopper may be engaged with the steering shaft so as to prevent relative rotation by other structures, such as serration engagement, key engagement, or concave-convex fitting.

[0058] The flange portions 22a and 22b are configured in a substantially plate-like shape. The radially outer surfaces (tip surfaces) of the flange portions 22a and 22b are aligned with the central axis O of the insertion hole 19. 19 It is configured as a partial cylindrical surface centered at .

[0059] Central axis O of the insertion hole 19 19 The diameter of an imaginary circle centered on the center axis of the steering shaft 9 and passing through the radially outer surfaces of the flange portions 22a, 22b is smaller than the diameter of a first imaginary circle centered on the center axis of the steering shaft 9 and passing through the radially inner end of the stationary-side stopper 16.

[0060] The mounting holes 21a and 21b provided in the pair of flange portions 22a and 22b penetrate the flange portions 22a and 22b in the plate thickness direction and are arranged coaxially with each other. 21 is the central axis O of the insertion hole 19 19 are arranged in a twisted position relative to the

[0061] In this example, one mounting hole 21a of the pair of mounting holes 21a, 21b is a cylindrical bolt insertion hole, and the other mounting hole 21b of the pair of mounting holes 21a, 21b is a screw hole.

[0062] The clamp portion 17 is fixed to the steering shaft 9 by inserting a fastening member 26 (see FIGS. 3 and 4) formed of a bolt through an attachment hole 21a provided in one flange portion 22a, threading the fastening member 26 into an attachment hole 21b provided in the other flange portion 22b, and further tightening the fastening member 26. In other words, the clamp portion 17 is detachably fixed to the steering shaft 9 by tightening the fastening member 26, which reduces the width dimension of the discontinuous portion 20 and elastically reduces the diameter thereof.

[0063] When implementing a rotation limiting device according to an embodiment of the present disclosure, the pair of mounting holes may be cylindrical holes, in which case nuts are threaded onto the tips of fastening members inserted through the pair of mounting holes.

[0064] The radial protrusion 18 is provided on the outer peripheral surface of the connecting portion 23 that constitutes the clamp portion 17. The radial protrusion 18 is disposed on the opposite side of the pair of flange portions 22a, 22b in the radial direction.

[0065] The radial outer surface (tip surface) of the radial protrusion 18 is aligned with the central axis O of the insertion hole 19. 19 It is configured as a partial cylindrical surface centered at .

[0066] Central axis O of the insertion hole 19 19 The diameter of an imaginary circle that is centered on and passes through the radially outer surface of the radial protrusion 18 is larger than the diameter of the first imaginary circle that passes through the radially inner end of the stationary-side stopper 16. In this example, the diameter of the imaginary circle that passes through the radially outer surface of the radial protrusion 18 is smaller than the diameter of a second imaginary circle that is centered on the central axis of the steering shaft 9 and passes through the radially outer end of the stationary-side stopper 16. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the diameter of the imaginary circle that passes through the radially outer surface of the radial protrusion may be the same as or slightly larger than the diameter of the second imaginary circle.

[0067] In the rotation-side stopper 15 of this example, the radial protrusion 18 and the mounting holes 21a, 21b of the clamp portion 17 are arranged at the same position in the front-to-rear direction. In other words, the radial protrusion 18 and the mounting holes 21a, 21b are arranged at positions that overlap in the circumferential direction.

[0068] In this example, the radial protrusion 18 has a symmetrical shape with respect to the first imaginary plane α. Therefore, the rotation-side stopper 15 has a symmetrical shape with respect to the first imaginary plane α, except for the shapes of the mounting holes 21 a and 21 b.

[0069] The radial protrusions 18 have a tapered shape in which the circumferential width decreases radially outward, except for the radially outer ends. The circumferential width of the radially outer ends of the radial protrusions 18 is constant throughout the radial direction.

[0070] The circumferential side surface of the radial protrusion 18 is composed of a convex curved surface portion 27, a concave curved surface portion 28, and a flat surface portion 29, in that order from the radially inner side.

[0071] The convex curved surface portion 27 occupies most of the circumferential side surface of the radial protrusion 18, and has a radius of curvature that is sufficiently larger than the inner diameter of the insertion hole 19. The concave curved surface portion 28 is located on the radially outer side of the circumferential side surface of the radial protrusion 18, and is smoothly connected to the radially outer end of the convex curved surface portion 27. The flat surface portion 29 is located on the radially outer end of the circumferential side surface of the radial protrusion 18, and is smoothly connected to the radially outer end of the concave curved surface portion 28.

[0072] In this example, the range of both circumferential side surfaces of the radial protrusion 18 from the radially outer end of the concave curved surface portion 28 to the flat surface portion 29 engages with the stationary stopper 16 in the circumferential direction.

[0073] In this example, the circumferential width of the tip of the radial protrusion 18, i.e., the central axis O of the insertion hole 19, is 19 The angle θ formed by the pair of flat surface portions 29 with the center at r (See FIG. 2) is not particularly limited as long as it can ensure strength and rigidity.

[0074] The rotation-side stopper 15 of this example has one side and the other side arranged on either side of a second imaginary plane β that includes the central axis of the steering shaft 9 and is perpendicular to the protruding direction of the radial protrusion 18 (the up-down direction in FIG. 15), and the product of the weight and the distance from the center of gravity to the central axis of the steering shaft 9 is equal to each other. In the rotation-side stopper 15 of this example, the fixing portion is the clamp portion 17 having the insertion hole 19 and the mounting holes 21a, 21b, so that when the fastening members 26 are inserted into the mounting holes 21a, 21b, the central axis O of the insertion hole 19 is equal to the distance from the center of gravity O of the radial protrusion 18. 19 and the central axis O of the mounting holes 21a and 21b 21 The one side portion including the pair of flange portions 22a, 22b and the other side portion including the radial protrusion portion 18 are arranged across a second imaginary plane β parallel to the axis β of the insertion hole 19. 19 The products of the distances to and are equal to each other.

[0075] When implementing the rotation limiting device according to an embodiment of the present disclosure, the rotation-side stopper may have different weights and distances from the center of gravity to the central axis of the steering shaft (the central axis of the insertion hole) between one side portion and the other side portion disposed on either side of the second imaginary plane β. In this case, it is preferable to make the product of the weight and distance for the other side portion greater than the product of the weight and distance for the one side portion.

[0076] As shown in Figures 2 and 6(A), the rotating side stopper 15 in this example is fixed to the front end of the steering shaft 9 so that the circumferential phase of the discontinuous portion 20 matches the stationary side stopper 16 when the steering wheel 3 is rotated to a neutral position where the pair of steered wheels 5 face in a straight-ahead direction.

[0077] <Stationary stopper> The stationary side stopper 16 is provided at the outer end of the reaction force applying device 10 in the radial direction of the steering shaft 9. In this example, the stationary side stopper 16 is provided in the housing 11 that constitutes the reaction force applying device 10.

[0078] The housing 11 is a cast product made of a light alloy such as an iron-based alloy or an aluminum alloy, and has a worm wheel receiving portion 30 for receiving a worm wheel (not shown) therein, and a worm receiving portion 31 for receiving a worm shaft (not shown) therein. The worm wheel receiving portion 30 has boss portions 32a to 32c at multiple locations (three locations in the illustrated example) on the radially outer end of the front side surface, which protrude forward more than the surrounding portions. The boss portions 32a to 32c protrude forward more than the surrounding portions, which makes them thicker. Threaded holes 33 are formed in the boss portions 32a to 32c.

[0079] In this example, the stationary side stopper 16 is provided at the radially outer end of the front side surface of the worm wheel accommodating portion 30. More specifically, the stationary side stopper 16 is fixed by screws to one boss portion 32a, out of multiple boss portions 32a to 32c provided on the front side surface of the worm wheel accommodating portion 30, which is located vertically above the steering shaft 9 when the steering column 8 is fixed to the vehicle body.

[0080] In this example, the stationary side stopper 16 is fixed to the boss portion 32a, which is located vertically above the steering shaft 9, among the multiple boss portions 32a to 32c, but the stationary side stopper 16 can also be fixed to the other boss portions 32b, 32c.

[0081] In this example, the stationary stopper 16 is configured separately from the housing 11 of the reaction force application device 10 and is fixed to the housing 11. However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the stationary stopper may be configured integrally with the housing of the reaction force application device. In this case, the boss portion formed on the housing can be increased in forward protrusion amount and used as the stationary stopper.

[0082] In this example, as shown in Fig. 4, the stationary stopper 16 is formed by a bolt. The stationary stopper 16 has an axial protrusion 34 formed by a head, and a threaded shank 35. The axial protrusion 34 and the threaded shank 35 are arranged coaxially. When implementing a rotation limiting device according to an embodiment of the present disclosure, the stationary stopper is not limited to a bolt, and can be formed by other members such as a pin or a nut.

[0083] The screw shaft portion 35 has a male thread on its outer circumferential surface, and is screwed into a threaded hole 33 of a boss portion 32 a provided in the housing 11 .

[0084] The axial protrusion 34 has a columnar shape and an outer peripheral surface that is a cylindrical surface. When the threaded shaft portion 35 is threadedly engaged with the threaded hole 33 of the boss portion 32a, the axial protrusion 34 is disposed so as to protrude forward from the tip end surface of the boss portion 32a. The axial protrusion 34 is disposed at the same position as the radial protrusion 18 in the front-rear direction. The axial dimension of the axial protrusion 34 is approximately the same as the thickness dimension of the tip end of the radial protrusion 18.

[0085] The diameter of the second imaginary circle passing through the outer end of the axial protrusion 34 in the radial direction is approximately the same as the diameter of the imaginary circle passing through the cylindrical outer circumferential surface of the worm wheel accommodating portion 30 .

[0086] The radius of curvature of the outer peripheral surface of the axial protrusion 34 is slightly larger than the radius of curvature of the concave curved surface portion 28 that constitutes the circumferential side surface of the radial protrusion 18 .

[0087] The outer diameter of the axial protrusion 34, that is, the angle θ formed between the ends of the axial protrusion 34 on both sides in the circumferential direction with the central axis of the steering shaft 9 as the center a is not particularly limited as long as it can ensure strength and rigidity.

[0088] In the rotation limiting device 2 of this example, when the steering wheel 3 is rotated left from the neutral state shown in Fig. 6(A), the end of one circumferential side of the stationary-side stopper 16 and the side surface of the other circumferential side of the rotation-side stopper 15 engage in the circumferential direction, as shown in Fig. 6(B), preventing further rotation of the steering wheel 3. Conversely, when the steering wheel 3 is rotated right from the neutral state shown in Fig. 6(A), the end of the other circumferential side of the stationary-side stopper 16 and the side surface of one circumferential side of the rotation-side stopper 15 engage in the circumferential direction, as shown in Fig. 6(C), preventing further rotation of the steering wheel 3.

[0089] The rotation limiting device 2 of this example can set the number of lock-to-lock rotations of the steering wheel 3 that can be rotated from one rotation limiting position shown in FIG. 6(B) to the other rotation limiting position shown in FIG. 6(C) to less than one rotation, specifically, to a rotation angle of, for example, 320 to 340 degrees (±160 to ±170 degrees from the neutral position). In the illustrated example, the number of lock-to-lock rotations of the steering wheel 3 is set to 332 degrees (±166 degrees from the neutral position). However, when implementing a rotation limiting device according to an embodiment of the present disclosure, the lock-to-lock rotation angle of the steering wheel is not limited to the range of 320 to 340 degrees, and can also be set to less than 320 degrees or to an angle greater than 340 degrees.

[0090] In this example, the stationary side stopper 16 and the rotating side stopper 15 are directly engaged, but when implementing a rotation limiting device according to one embodiment of the present disclosure, in order to suppress the generation of collision noise, the stationary side stopper and / or the rotating side stopper may be partially or entirely covered with a resin coating (sleeve) or the like, and the stationary side stopper and the rotating side stopper may be indirectly engaged.

[0091] According to the rotation limiting device 2 of this example, the work efficiency of the assembly process of the steering device 1 can be improved.

[0092] The rotation limiting device 2 includes a rotation-side stopper 15 fixed to the front end of the steering shaft 9 so as to prevent relative rotation, and a stationary-side stopper 16 provided in the reaction force imparting device 10 at a position radially offset from the central axis of the steering shaft 9 and protruding forward. Therefore, when running-in the reaction force imparting device 10 during the assembly process of the steering device 1, the run-in can be performed with the rotation-limiting device 2 removed. Specifically, the run-in of the reaction force imparting device 10 can be performed with the rotation-side stopper 15 removed from the front end of the steering shaft 9 and / or with the stationary-side stopper 16 removed from the reaction force imparting device 10. This means that the rotation of the steering shaft 9 is not limited by the rotation limiting device 2, improving the work efficiency of the assembly process of the steering device 1.

[0093] Furthermore, the rotation-side stopper 15 has a clamp portion 17 that reduces in diameter when fastened by a fastening member 26 and is detachably fixed to the front end of the steering shaft 9, and a radial protrusion 18 that protrudes radially from the outer circumferential surface of the clamp portion 17 and is circumferentially engageable with the stationary-side stopper 16. This improves the efficiency of the work of attaching and detaching the rotation-side stopper 15 to and from the steering shaft 9. Furthermore, because the configuration of the rotation-side stopper 15 is simplified, the number of parts of the rotation limiting device 2 can be kept small.

[0094] In this example, the stationary-side stopper 16 is provided at the outer end of the reaction force applying device 10 in the radial direction of the steering shaft 9. This ensures a wide space between the stationary-side stopper 16 and the steering shaft 9, thereby ensuring sufficient strength for the rotation-side stopper 15 placed in that space. Therefore, when the stationary-side stopper 16 and the rotation-side stopper 15 engage in the circumferential direction, damage to the rotation-side stopper 15 can be suppressed.

[0095] In this example, the stationary-side stopper 16 is fixed by screws to the boss portion 32a provided on the housing 11 that constitutes the reaction force applying device 10, so that the fixing strength of the stationary-side stopper 16 to the housing 11 can be sufficiently ensured. Also, in this example, the stationary-side stopper 16 is configured separately from the housing 11 that constitutes the reaction force applying device 10, so the stationary-side stopper 16 can be made of a different material from the housing 11. This improves the degree of freedom in designing the stationary-side stopper 16. Also, the stationary-side stopper 16 can be provided to an existing reaction force applying device 10.

[0096] In this example, the mounting holes 21a, 21b and the radial protrusion 18 of the clamp portion 17 are arranged at the same position in the front-rear direction, so that the rotation of the rotation-side stopper 15 is stabilized.

[0097] The rotation-side stopper 15 of this example has a weight and a distance from the center of gravity to the central axis O of the insertion hole 19, which are determined by one side portion including the pair of flange portions 22a, 22b arranged on either side of the second imaginary plane β and the other side portion including the radial protrusion portion 18. 19 The product of the distance from the rotation side stopper 15 to the steering shaft 9 is set equal to each other. This makes it possible to prevent the rotation balance of the steering shaft 9 to which the rotation side stopper 15 is fixed from becoming poor.

[0098] When implementing a rotation limiting device according to one embodiment of the present disclosure, the product of the weight and distance of the other side portion is made greater than the product of the weight and distance of the one side portion, and the stationary side stopper is positioned directly above the steering shaft in the vertical direction, so that the weight of the rotating side stopper can be used to return the steering wheel to the neutral position.

[0099] In this example, by replacing the stationary side stopper 16 with another stationary side stopper 16 having a different outer diameter (circumferential width), and / or by replacing the rotating side stopper 15 with another rotating side stopper 15 having a different circumferential width at the tip, the lock-to-lock rotation speed of the steering wheel 3 can be easily changed, thereby improving design freedom. [Explanation of symbols]

[0100] 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 Rotation side stopper 16 Stationary side stopper 17 Clamp section 18 Radial protrusion 19 Insertion hole 20 Discontinuities 21a, 21b Mounting holes 22a, 22b flange part 23 Connecting part 24 Female spline part 25 Male spline part 26 Fastening members 27 Convex curved surface part 28 Concave curved part 29 Flat surface section 30 Worm wheel housing 31 Worm housing 32a~32c Boss part 33 screw holes 34 Axial protrusion 35 Screw shaft

Claims

1. a rotation side stopper fixed to a front end of the steering shaft so as to be non-rotatable relative to the steering shaft; a stationary stopper provided in a position radially offset from a central axis of the steering shaft and protruding forward, in a reaction force applying device that applies a reaction force to the steering shaft; The rotation-side stopper has a fixed portion that is detachably fixed to a front end portion of the steering shaft, and a radial protrusion that protrudes radially from an outer circumferential surface of the fixed portion and is circumferentially engageable with the stationary-side stopper. Rotation limiter.

2. 2. The rotation limiting device according to claim 1, wherein the stationary stopper is provided at an outer end of the reaction force applying device in the radial direction of the steering shaft.

3. the fixing portion is a clamp portion that is reduced in diameter by fastening a fastening member and is fixed to the front end portion of the steering shaft, The rotation limiting device of claim 1 .

4. 4. The rotation limiting device according to claim 3, wherein the clamp portion has an insertion hole into which the front end of the steering shaft can be inserted, a discontinuous portion provided at one location in the circumferential direction, a pair of flange portions disposed on both sides of the discontinuous portion and provided with mounting holes into which the fastening member can be inserted, and a partially cylindrical connecting portion connecting the pair of flange portions.

5. The rotation limiting device according to claim 4 , wherein the mounting hole and the radial protrusion are disposed at the same position in the front-rear direction.

6. 2. The rotation limiting device according to claim 1, wherein the rotation side stopper includes a central axis of the steering shaft, and the product of weight and distance from the center of gravity to the central axis of the steering shaft is equal between one side portion and the other side portion arranged on either side of an imaginary plane that includes the central axis of the steering shaft and is perpendicular to the protruding direction of the radial protrusion.

7. 2. The rotation limiting device according to claim 1, wherein the rotation side stopper includes a central axis of the steering shaft, and one side portion and the other side portion are arranged on opposite sides of an imaginary plane that is perpendicular to the protruding direction of the radial protrusion, and the product of the weight and the distance from the center of gravity to the central axis of the steering shaft is different from each other.

8. a steering shaft, a reaction force applying device, and a rotation limiting device that limits the amount of rotation of the steering shaft to a predetermined value; A steering unit, wherein the rotation limiting device is a rotation limiting device according to any one of claims 1 to 7.

9. The vehicle is provided with a steering unit, a turning unit that applies a steering angle to a steering wheel, and a control unit, the steering unit and the steered unit are not mechanically connected to each other, but are electrically connected to each other via the control unit, The steering unit is a steering unit according to claim 8. Steering device.

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