Steering stopper device

Abstract

A steering stopper device has an external gear (20), a first internal gear (21), and a second internal gear (22). The first internal gear (21) is provided with a stopper protrusion (40), and the second internal gear (22) is provided with stopper receiving parts (42). The rotation angle of a steering wheel (2) is regulated by the stopper protrusion (40) circumferentially abutting on the stopper receiving parts (42).

Description

Steering stopper device

[0001] This invention relates to a steering stopper device that restricts the rotation angle of a steering wheel.

[0002] A steer-by-wire system is known as a steering device that changes the direction of the vehicle's steering wheels in response to the driver's rotation of the steering wheel (for example, Patent Documents 1 and 2). A steer-by-wire steering device has a steering sensor that detects the amount of steering wheel operation and a steering actuator that is mechanically disconnected from the steering wheel. The steering actuator operates in accordance with the amount of steering wheel operation detected by the steering sensor, changing the direction of a pair of left and right steering wheels.

[0003] This steer-by-wire steering system converts the driver's steering wheel input into an electrical signal, and then controls the operation of the steering actuator based on that electrical signal. For example, it can adjust the amount of change in the direction of the steering wheels when the steering wheel is operated according to the vehicle's speed. This allows for the optimization of the relationship between the steering wheel input and the steering actuator's operation according to the vehicle's speed, and is expected to improve the vehicle's driving stability and handling performance.

[0004] Incidentally, the steering devices described in Patent Documents 1 and 2 incorporate a steering stopper device that prevents the steering wheel from being rotated beyond a preset angle range.

[0005] Japanese Patent Publication No. 2021-172202 Japanese Patent Publication No. 2021-172231

[0006] The steering stopper device described in Patent Document 1 is configured such that a stopper projection is provided at one location in the circumferential direction on the outer circumference of the steering shaft, which rotates integrally with the steering wheel, and a stopper receiving portion is provided at one location in the circumferential direction on the inner circumference of a cylindrical steering column that rotatably houses the steering shaft, and the rotation angle of the steering wheel is restricted by the stopper projection contacting the stopper receiving portion in the circumferential direction.

[0007] The steering stopper device described in Patent Document 1 is configured such that a stopper projection on the outer circumference of the steering shaft and a stopper receiving portion on the inner circumference of the steering column come into contact in the circumferential direction. Therefore, the position in which the rotation of the steering wheel is restricted can only be set within an angular range of less than 360° (i.e., less than ±180° from the neutral position).

[0008] However, vehicle steering wheels are typically used within an angle range exceeding 360°.

[0009] Therefore, a multi-stage steering stopper device is known that allows the position in which the rotation of the steering wheel is restricted to be set within an angular range exceeding 360° (i.e., an angular range exceeding ±180° from the neutral position) (for example, Patent Document 2).

[0010] The steering stopper device described in Patent Document 2 has a first rotating member, a second rotating member, and a fixed member arranged sequentially in the axial direction. When the steering wheel is rotated from the neutral position, the first rotating member rotates together with the steering wheel. When the first rotating member rotates by a predetermined angle of less than 180°, a first stopper projection on the first rotating member comes into circumferential contact with a first stopper receiving on the second rotating member, and this contact causes the second rotating member to begin rotating together with the first rotating member. Furthermore, when the second rotating member rotates by a predetermined angle of less than 180°, a second stopper projection on the second rotating member comes into circumferential contact with a second stopper receiving on the fixed member, and this contact prevents further rotation of the second rotating member, thus preventing the rotation of the steering wheel. Thus, the steering stopper device of Patent Document 2 is equipped with multiple stopper mechanisms that restrict rotation at a predetermined angle of less than 180°, and by connecting these multiple stopper mechanisms in the axial direction, it is possible to set the position in which the rotation of the steering wheel is restricted to an angular range exceeding 360° (an angular range exceeding ±180° from the neutral position).

[0011] However, the steering stopper device described in Patent Document 2 has a configuration in which multiple stopper mechanisms are connected in the axial direction, which has the problem of increasing the size in the axial direction.

[0012] Furthermore, the inventors of the present invention have considered a steering stopper device that can set the position in which the rotation of the steering wheel is restricted to an angular range exceeding 360°. This device comprises a steering shaft that rotates integrally with the steering wheel connected to the input shaft of the reduction gear, a stopper projection provided on the output shaft of the reduction gear, and a stopper receiving portion provided on the housing of the reduction gear to receive the stopper projection in the circumferential direction.

[0013] With this configuration, the rotation angle of the output shaft of the reduction gear when the steering wheel is rotated is smaller than the rotation angle of the steering wheel, making it possible to set the position where the rotation of the steering wheel is restricted to an angle range exceeding 360°.

[0014] However, if the stopper projection on the output shaft of the gearbox is supported in the circumferential direction by a stopper receiving portion on the housing of the gearbox, a problem of insufficient strength arises.

[0015] In other words, when rotational torque is input to the input shaft of the reduction gear, the rotational torque increased by the reduction is output from the output shaft of the reduction gear. Therefore, if a stopper projection provided on the output shaft of the reduction gear is supported in the circumferential direction by a stopper receiving portion provided on the reduction gear housing, a large load will be placed on the stopper projection and the stopper receiving portion, resulting in a problem of insufficient strength.

[0016] The problem that this invention aims to solve is to provide a steering stopper device that allows the position in which the rotation of the steering wheel is restricted to be set within an angular range exceeding 360°, does not require high strength, and is compact in the axial direction.

[0017] To solve the above problems, this invention provides a steering stopper device having the following configuration: [Configuration 1] An external gear having a plurality of first external teeth arranged in the circumferential direction and a plurality of second external teeth arranged in the circumferential direction adjacent to the first external teeth in the axial direction on its outer circumference; an annular first internal gear having a plurality of first internal teeth on its inner circumference that mesh with the first external teeth; and an annular second internal gear arranged adjacent to the first internal gear in the axial direction and having a plurality of second internal teeth on its inner circumference that mesh with the second external teeth, wherein the reduction ratio i between the external gear and the first internal gear is obtained by dividing the number of teeth of the first internal teeth by the number of teeth of the first external teeth １ However, the reduction ratio i between the external gear and the second internal gear is obtained by dividing the number of teeth of the second internal gear by the number of teeth of the second external gear. ２ Unlike the above, the first internal gear is provided with a stopper projection that rotates integrally with the first internal gear, and the second internal gear is provided with a stopper receiving portion that rotates integrally with the second internal gear, and the steering stopper device restricts the rotation angle of the steering wheel by the stopper projection contacting the stopper receiving portion in the circumferential direction.

[0018] With this configuration, when the steering wheel is rotated, the external gear rotates, and the first and second internal gears that mesh with the external gear also rotate. Here, the reduction ratio i of the external gear and the first internal gear １ The reduction ratio i between the external gear and the second internal gear ２ Because they are different, the first internal gear and the second internal gear rotate in the same direction with a speed difference. Then, the stopper projection that rotates integrally with the first internal gear and the stopper receiving part that rotates integrally with the second internal gear move circumferentially with a speed difference, and when the stopper projection comes into contact with the stopper receiving part in the circumferential direction, further relative rotation between the first internal gear and the second internal gear is prevented, and as a result, the rotation of the steering wheel is also prevented.

[0019] Thus, this steering stopper device uses the difference in rotational speed between the first internal gear and the second internal gear to bring the stopper projection and the stopper receiving portion into contact, making it possible to set the position in which the rotation of the steering wheel is restricted to an angular range exceeding 360°.

[0020] Furthermore, when the stopper projection contacts the stopper receiving portion, the rotational torque of either the first or second internal gear acts directly on the stopper projection and the stopper receiving portion, rather than the rotational torque that is reduced and increased by the difference in rotational speed between the first and second internal gears. Therefore, the load on the stopper projection and the stopper receiving portion can be kept low, and high strength is not required.

[0021] Furthermore, its simple configuration, consisting only of annular first and second internal gears that mesh with a common external gear and are arranged adjacent to each other in the axial direction, makes it compact in the axial direction.

[0022] [Configuration 2] The steering stopper device according to Configuration 1, wherein the stopper projection is a projection provided on the axial end face of the first internal gear on the side of the second internal gear, the axial end face of the second internal gear on the side of the first internal gear is provided with a circumferential groove that movably accommodates the stopper projection in the circumferential direction and extends in the circumferential direction within an angular range of less than 360°, and the stopper receiving portion is the circumferential end face of the circumferential groove.

[0023] When this configuration is adopted, the stopper convex portion provided on the axial end face of the first internal gear is accommodated in the circumferential groove provided on the axial end face of the second internal gear. Therefore, the axial interval between the axial end face of the first internal gear and the axial end face of the second internal gear can be reduced. As a result, it is possible to effectively reduce the axial length of the steering stopper device.

[0024] [Configuration 3] A plurality of external teeth extending axially from the portion surrounded by the first internal gear to the portion surrounded by the second internal gear are provided side by side in the circumferential direction on the outer periphery of the external gear. The first external teeth are the portions of the respective external teeth on the side of the first internal gear, and the second external teeth are the portions of the respective external teeth on the side of the second internal gear. The steering stopper device according to Configuration 1 or 2.

[0025] When this configuration is adopted, since the first external teeth (teeth meshing with the first internal teeth on the inner periphery of the first internal gear) and the second external teeth (teeth meshing with the second internal teeth on the inner periphery of the second internal gear) are common external teeth, it is possible to suppress the processing cost of the external gear.

[0026] [Configuration 4] The deceleration ratio i between the external gear and the first internal gear and the deceleration ratio i between the external gear and the second internal gear are set such that the absolute value of the difference between (1 / i １ ) and (1 / i ２ ) is 1 / 10 or less. The steering stopper device according to any one of Configurations 1 to 3. １ and the deceleration ratio i between the external gear and the second internal gear ２ are set.

[0027] When this configuration is adopted, since the rotational speed difference between the first internal gear and the second internal gear is small, it is possible to surely set the position where the rotation of the steering wheel is restricted to an angular range exceeding 360°.

[0028] [Configuration 5] The steering stopper device according to any one of Configurations 1 to 4, in which the first internal gear and the second internal gear are arranged eccentrically in the same direction with respect to the rotation center of the external gear.

[0029] When this configuration is adopted, since the first internal gear and the second internal gear are arranged eccentrically in the same direction with respect to the rotation center of the external gear, most of the first internal gear and most of the second internal gear overlap when viewed from the axial direction, and it is compact in the radial direction.

[0030] [Configuration 6] It further has a housing for accommodating the first internal gear and the second internal gear, and the housing is formed by axially connecting a first split housing in which a cylindrical first accommodation hole for accommodating the first internal gear is formed, and a second split housing for accommodating the second internal gear and having a cylindrical second accommodation hole centered at a position eccentric with respect to the center position of the first accommodation hole. The steering stopper device according to any one of Configurations 1 to 5.

[0031] When this configuration is adopted, since the housing for accommodating the first internal gear and the second internal gear is axially divided into a first split housing for accommodating the first internal gear and a second split housing for accommodating the second internal gear, the first internal gear and the second internal gear are easy to incorporate.

[0032] The steering stopper device of this invention abuts the stopper convex portion and the stopper receiving portion due to the rotational speed difference between the first internal gear and the second internal gear, so the position where the rotation of the steering wheel is restricted can be set in an angular range exceeding 360°.

[0033] Further, when the stopper convex portion abuts the stopper receiving portion, the rotational torque of the first internal gear or the second internal gear acts as it is on the stopper convex portion and the stopper receiving portion, rather than the rotational torque that has increased after deceleration due to the rotational speed difference between the first internal gear and the second internal gear. Therefore, the load applied to the stopper convex portion and the stopper receiving portion can be kept low, and high strength is not required.

[0034] Also, since it has a simple configuration in which the annular first internal gear and the second internal gear that mesh with a common external gear are arranged adjacent to each other in the axial direction, it is compact in the axial direction.

[0035] Figure 1 schematically shows a steering device using a steering stopper device according to an embodiment of this invention. Cross-sectional view of the steering stopper device shown in Figure 1. Cross-sectional view along line III-III in Figure 2. Cross-sectional view along line IV-IV in Figure 2. Exploded perspective view of the external gear, first internal gear and second internal gear shown in Figure 2. (a) is a diagram showing the positional relationship between the stopper projection and the stopper receiving part when the steering shaft is in the neutral position. (b) is a diagram showing the positional relationship between the stopper projection and the stopper receiving part when the external gear shown in (a) is rotated counterclockwise once. (c) is a diagram showing the positional relationship between the stopper projection and the stopper receiving part when the external gear shown in (a) is rotated counterclockwise twice.

[0036] Figure 1 shows a steering system incorporating a steering stopper device 1 according to an embodiment of the present invention. This steering system is a steer-by-wire type vehicle steering system that converts the amount of operation of the steering wheel 2 by the driver into an electrical signal and controls the steering actuator 3 based on that electrical signal to change the direction of a pair of left and right steering wheels 4.

[0037] This steering system includes a steering wheel 2 steered by the driver, a steering shaft 5 connected to the steering wheel 2, a steering sensor 6 that detects the amount of movement of the steering wheel 2, a reaction force motor 7 that applies a steering reaction force to the steering wheel 2, a steering stopper device 1 that restricts the rotation angle of the steering wheel 2, a steering actuator 3 that is mechanically disconnected from the steering wheel 2, and a control unit 8.

[0038] The steering shaft 5 is connected to the steering wheel 2 so as to rotate together with the steering wheel 2 when the steering wheel 2 is turned. The steering sensor 6 is attached to the steering shaft 5. Examples of the steering sensor 6 include a steering angle sensor that detects the steering angle of the steering wheel 2, and a steering torque sensor that detects the steering torque input to the steering wheel 2 by the driver.

[0039] The reaction motor 7 is an electric motor that generates rotational torque when energized. The reaction motor 7 is connected to the end of the steering shaft 5. By inputting rotational torque to the steering shaft 5, the reaction motor 7 applies a steering reaction force to the steering wheel 2 via the steering shaft 5.

[0040] The steering actuator 3 comprises a steering shaft 9, a steering shaft housing 10, a steering motor 11 for moving the steering shaft 9 in the left-right direction of the vehicle, and a steering sensor 12 for detecting the position of the steering shaft 9. The steering shaft 9 is supported by the steering shaft housing 10 so as to be movable in the left-right direction of the vehicle. The steering shaft housing 10 accommodates the central part of the steering shaft 9 such that both the left and right ends of the steering shaft 9 protrude from the steering shaft housing 10.

[0041] The steering motor 11 and steering sensor 12 are mounted on the steering shaft housing 10. Between the steering motor 11 and the steering shaft 9, a motion conversion mechanism (not shown) is incorporated to convert the rotation output by the steering motor 11 into linear motion of the steering shaft 9. Both the left and right ends of the steering shaft 9 are connected to a pair of left and right steering wheels 4 via tie rods 13, so that when the steering shaft 9 moves in the left and right direction, the orientation of the pair of left and right steering wheels 4 changes in conjunction with it.

[0042] The control unit 8 operates the steering motor 11 in accordance with the amount of steering wheel 2 operated by the steering sensor 6 and the vehicle's driving conditions (vehicle speed, etc.) detected by the external sensor 14, thereby controlling the direction of the left and right pair of steering wheels 4. At the same time, the control unit 8 operates the reaction force motor 7 so that a steering reaction force of a magnitude corresponding to the amount of steering wheel 2 operated and the vehicle's driving conditions is generated.

[0043] As shown in Figure 2, the reaction motor 7 has a motor case 15 and a motor shaft 16 that protrudes from the motor case 15 on the side opposite to the steering wheel 2 (see Figure 1) (to the left in the figure). The motor shaft 16 is connected to the steering shaft 5 (see Figure 1) so as to rotate integrally with the steering shaft 5. The motor case 15 is fixed to the vehicle body (not shown) so as not to rotate even when the steering shaft 5 (see Figure 1) rotates.

[0044] The steering stopper device 1 includes an external gear 20 to which the rotation of the steering wheel 2 (see Figure 1) is input via a motor shaft 16, an annular first internal gear 21 and a second internal gear 22 surrounding the external gear 20, and a housing 23 that houses the first internal gear 21 and the second internal gear 22. The housing 23 is fixed to the motor case 15 with bolts 24.

[0045] The external gear 20 has a through hole 25 that penetrates axially, and the inner circumference of the through hole 25 is fitted to the outer circumference of a shaft (in this case, a motor shaft 16) that rotates integrally with the steering wheel 2 (see Figure 1). The fitting between the through hole 25 and the motor shaft 16 is a rotation-preventing fit (such as a spline fit, keyway fit, or fit with an overlap; in the figure, a spline fit) that prevents the external gear 20 from rotating on the motor shaft 16.

[0046] The external gear 20 has a gear body 28 with a plurality of first external teeth 26 arranged in the circumferential direction and a plurality of second external teeth 27 arranged in the circumferential direction at positions adjacent to the first external teeth 26 in the axial direction on its outer circumference, a first shaft portion 29 protruding from the gear body 28 to one axial side (right side in the figure), and a second shaft portion 30 protruding from the gear body 28 to the other axial side (left side in the figure). The first shaft portion 29 and the second shaft portion 30 are rotatably supported by a first bearing 31 and a second bearing 32 assembled to the housing 23. The gear body 28, the first shaft portion 29, and the second shaft portion 30 are integrally formed from metal (for example, steel).

[0047] The first external teeth 26 are provided over the entire circumference of the outer periphery of the gear main body 28 at a constant pitch, and the second external teeth 27 are also provided over the entire circumference of the outer periphery of the gear main body 28 at a constant pitch. The first external teeth 26 and the second external teeth 27 can be separate external teeth with different numbers of teeth, but here they are common external teeth. That is, on the outer periphery of the gear main body 28 of the external gear 20, a plurality of external teeth extending axially from the portion surrounded by the first internal gear 21 to the portion surrounded by the second internal gear 22 are provided side by side in the circumferential direction. The portion of each external tooth on the side of the first internal gear 21 (the right side portion in the figure) is the first external tooth 26, and the portion of each external tooth on the side of the second internal gear 22 (the left side portion in the figure) is the second external tooth 27. Therefore, the number of teeth of the first external tooth 26 and the number of teeth of the second external tooth 27 are the same.

[0048] As shown in FIG. 3, on the inner periphery of the first internal gear 21, a plurality of first internal teeth 33 are provided over the entire circumference at a constant pitch, and the plurality of first internal teeth 33 mesh with the first external teeth 26 on the outer periphery of the external gear 20 at one position in the circumferential direction (the lower position in the figure). The number of teeth of the first internal teeth 33 on the inner periphery of the first internal gear 21 is larger than the number of teeth of the first external teeth 26 on the outer periphery of the external gear 20. The reduction ratio i of the external gear 20 and the first internal gear 21 obtained by dividing the number of teeth of the first internal teeth 33 by the number of teeth of the first external teeth 26 １ is set in the range of 1.0 < i １ < 1.5 (preferably, 1.0 < i １ < 1.3).

[0049] As shown in FIG. 4, on the inner periphery of the second internal gear 22, a plurality of second internal teeth 34 are also provided over the entire circumference at a constant pitch, and the second internal teeth 34 mesh with the second external teeth 27 on the outer periphery of the external gear 20 at one position in the circumferential direction (the lower position in the figure). The number of teeth of the second internal teeth 34 on the inner periphery of the second internal gear 22 is larger than the number of teeth of the second external teeth 27 on the outer periphery of the external gear 20. The reduction ratio i of the external gear 20 and the second internal gear 22 obtained by dividing the number of teeth of the second internal teeth 34 by the number of teeth of the second external teeth 27 ２ is set in the range of 1.0 < i ２ < 1.5 (preferably, 1.0 < i ２ < 1.3).

[0050] Here, the number of teeth of the first internal gear 33 is different from the number of teeth of the second internal gear 34, and as a result, the reduction ratio i of the external gear 20 and the first internal gear 21 １ However, the reduction ratio i of the external gear 20 and the second internal gear 22 ２ They are of different sizes. Also, the number of teeth of the first internal tooth 33 and the number of teeth of the second internal tooth 34 are (1 / i １ ) and (1 / i ２ The values ​​are set to be close enough that the absolute value of the difference between them is 1 / 10 or less (preferably 1 / 20 or less).

[0051] For example, if the number of teeth of the first external gear 26 and the second external gear 27 is set to 40, the number of teeth of the first internal gear 33 can be set to 48 and the number of teeth of the second internal gear 34 can be set to 46. In this case, the reduction ratio i of the external gear 20 and the first internal gear 21 １ This is 48 / 40 = 1.2, and the reduction ratio i of the external gear 20 and the second internal gear 22. ２ Therefore, 46 / 40 = 1.15. And (1 / i １ ) and (1 / i ２ The absolute value of the difference between (40 / 48) and (40 / 46) is |(40 / 46)| = (5 / 138), which is less than 1 / 20.

[0052] As shown in Figure 2, the first internal gear 21 and the second internal gear 22 are arranged adjacent to each other in the axial direction within the housing 23. The housing 23 has a first split housing 23A with a first housing hole 35 for housing the first internal gear 21 and a second split housing 23B with a second housing hole 36 for housing the second internal gear 22. The first split housing 23A incorporates a first bearing 31 that supports the first shaft portion 29 of the external gear 20, and the second split housing 23B incorporates a second bearing 32 that supports the second shaft portion 30 of the external gear 20.

[0053] The first split housing 23A and the second split housing 23B are connected axially by bolts 37. A cylindrical protrusion 38 is formed on one of the mating surfaces of the first split housing 23A and the second split housing 23B (in the figure, the mating surface of the first split housing 23A with the second split housing 23B), with its center at the same position as the rotation center of the external gear 20. A cylindrical recess 39 is formed on the other mating surface of the first split housing 23A and the second split housing 23B (in the figure, the mating surface of the second split housing 23B with the first split housing 23A), with its center at the same position as the rotation center of the external gear 20. By fitting the protrusion 38 and the recess 39 together, the first split housing 23A and the second split housing 23B are positioned radially.

[0054] As shown in Figure 3, the inner circumferential surface of the first housing hole 35 is formed in a cylindrical shape with its center eccentrically located with respect to the rotation center of the external gear 20 (the center position of the motor shaft 16 in the figure), and the outer circumference of the first internal gear 21 is rotatably supported by its inner circumferential surface. In the figure, in order to reduce the number of parts, the outer circumference of the first internal gear 21 is directly supported by the inner circumferential surface of the first housing hole 35, but a bearing (not shown) may be fitted and provided on the inner circumferential surface of the first housing hole 35, and the outer circumference of the first internal gear 21 may be rotatably supported via the bearing.

[0055] As shown in Figure 4, the inner circumferential surface of the second housing hole 36 is also formed in a cylindrical shape with its center eccentrically located with respect to the rotation center of the external gear 20 (the center position of the motor shaft 16 in the figure), and its inner circumferential surface rotatably supports the outer circumference of the second internal gear 22.

[0056] As shown in Figure 2, the eccentric direction of the inner surface of the first housing hole 35 with respect to the rotation center of the external gear 20 (upward in the figure) is the same as the eccentric direction of the inner surface of the second housing hole 36 with respect to the rotation center of the external gear 20 (upward in the figure). As a result, the first internal gear 21 and the second internal gear 22 are supported so as to be rotatable around a position eccentric to the rotation center of the external gear 20 in the same direction (upward in the figure). Furthermore, the center position of the inner surface of the first housing hole 35 does not coincide with the center position of the inner surface of the second housing hole 36. That is, the inner surface of the second housing hole 36 is formed to have its center at a position eccentric to the center position of the inner surface of the first housing hole 35 (a position eccentric downward in the figure).

[0057] The first internal gear 21 is provided with a stopper projection 40 that protrudes from the axial end face of the first internal gear 21 on the side of the second internal gear 22 (left side in the figure) toward the side of the second internal gear 22 (left side in the figure). The stopper projection 40 is a projection provided so as to rotate integrally with the first internal gear 21 when the first internal gear 21 rotates. It is also possible to attach a stopper projection 40 (such as a pin or screw member) that is formed separately from the first internal gear 21 to the first internal gear 21, but as shown in the figure, forming the stopper projection 40 integrally with the first internal gear 21 is advantageous in terms of strength because the stopper projection 40 can be formed from the same high-strength material as the first internal gear 21.

[0058] A circumferential groove 41 is formed on the axial end face of the second internal gear 22 on the side of the first internal gear 21 (right side in the figure) to accommodate the stopper projection 40 so as to be movable in the circumferential direction. As shown in Figures 4 and 5, the circumferential groove 41 is a groove that extends in the circumferential direction within an angular range of less than 360° (90° or less in the figure). The circumferential end faces of the circumferential groove 41 and the other end face constitute a stopper receiving portion 42 that receives the stopper projection 40 in the circumferential direction, as will be described later.

[0059] The steering stopper device 1 shown in Figure 2 works as follows: when the steering wheel 2 (see Figure 1) is rotated, the rotation is input to the external gear 20 via the motor shaft 16, causing the external gear 20 to rotate, and the first internal gear 21 and the second internal gear 22 that mesh with the external gear 20 also rotate. Here, the reduction ratio i of the external gear 20 and the first internal gear 21 １ The reduction ratio i of the external gear 20 and the second internal gear 22 ２ Because they are different, the first internal gear 21 and the second internal gear 22 rotate in the same direction with a speed difference. Then, as shown in Figures 6(a) to (c), the stopper projection 40 that rotates integrally with the first internal gear 21 and the stopper receiving portion 42 that rotates integrally with the second internal gear 22 move circumferentially with a speed difference, and when the stopper projection 40 comes into contact with the stopper receiving portion 42 in the circumferential direction, further relative rotation between the first internal gear 21 and the second internal gear 22 is prevented, and as a result, the rotation of the steering wheel 2 shown in Figure 1 is also prevented.

[0060] Figure 2 shows the number of teeth on the external gear 20, the number of teeth on the first internal gear 33 is 48, the number of teeth on the second internal gear 34 is 46, and the reduction ratio i of the external gear 20 and the first internal gear 21. １ The reduction ratio i of the external gear 20 and the second internal gear 22 is 1.2. ２ Let's take the case where the value is 1.15 as an example. In the state shown in Figure 6(a) (the state in which the steering wheel 2 shown in Figure 1 is in the neutral position), the angle θ from the stopper projection 40 to the stopper receiving portion 42 is set to 26°.

[0061] Then, when the steering wheel 2 shown in Figure 1 is rotated 1 turn counterclockwise from the neutral position, the external gear 20 shown in Figure 6(a) rotates 360° counterclockwise. At this time, the first internal gear 21 shown in Figure 3 rotates 300° counterclockwise (= 360° / 1.2), and the second internal gear 22 shown in Figure 6(a) rotates 313° counterclockwise (= 360° / 1.15). As a result, the first internal gear 21 shown in Figure 3 rotates 13° clockwise relative to the second internal gear 22, so as shown in Figure 6(b), the angle from the stopper projection 40 to the stopper receiving portion 42 becomes 13°, and the remaining angle θ from the stopper projection 40 to the stopper receiving portion 42 becomes 13° (= 26° - 13°).

[0062] Furthermore, when the steering wheel 2 shown in Figure 1 is rotated 1 turn counterclockwise, the external gear 20 shown in Figure 6(b) rotates 360° counterclockwise, the first internal gear 21 shown in Figure 3 rotates 300° counterclockwise, and the second internal gear 22 shown in Figure 6(b) rotates 313° counterclockwise. As a result, as shown in Figure 6(c), the angle from the stopper projection 40 to the stopper receiving portion 42 narrows by another 13°, and the remaining angle from the stopper projection 40 to the stopper receiving portion 42 becomes 0° (= 13° - 13°), so the stopper projection 40 comes into contact with the stopper receiving portion 42 in the circumferential direction. This contact prevents the steering wheel 2 shown in Figure 1 from rotating any further counterclockwise.

[0063] This steering stopper device 1 brings the stopper projection 40 and the stopper receiving portion 42 into contact due to the difference in rotational speed between the first internal gear 21 and the second internal gear 22 shown in Figure 2. Therefore, the position in which the rotation of the steering wheel 2 shown in Figure 1 is restricted can be set to an angular range exceeding 360° (1440° in the above example (an angular range of ±720° from the neutral position)).

[0064] Here, the rotation angle from the neutral position of the steering wheel 2 to the position where rotation is restricted is ±N°, and the reduction ratio of the external gear 20 and the first internal gear 21 shown in Figure 2 is i １ The reduction ratio of the external gear 20 and the second internal gear 22 is set to i ２ In this case, the angle θ from the stopper projection 40 to the stopper receiving portion 42 shown in Figure 6(a) is θ = N × |(1 / i １ ) - (1 / i ２ It can be calculated using the formula )|.

[0065] Furthermore, as shown in Figure 6(c), when the stopper projection 40 contacts the stopper receiving portion 42, the rotational torque of either the first internal gear 21 or the second internal gear 22 acts directly on the stopper projection 40 and the stopper receiving portion 42, rather than the rotational torque that is reduced and increased by the difference in rotational speed between the first internal gear 21 and the second internal gear 22 as shown in Figure 2. Therefore, the load on the stopper projection 40 and the stopper receiving portion 42 can be kept low, and high strength is not required.

[0066] Furthermore, as shown in Figure 2, the steering stopper device 1 has a simple configuration consisting only of annular first internal gear 21 and second internal gear 22 that mesh with a common external gear 20, arranged adjacent to each other in the axial direction, making it compact in the axial direction.

[0067] Furthermore, as shown in Figure 2, the steering stopper device 1 has a stopper projection 40 provided on the axial end face of the first internal gear 21 that is housed in a circumferential groove 41 provided on the axial end face of the second internal gear 22. This allows for a reduction in the axial distance between the axial end face of the first internal gear 21 and the axial end face of the second internal gear 22. As a result, the axial length of the steering stopper device 1 can be effectively reduced.

[0068] Furthermore, as shown in Figure 2, the steering stopper device 1 uses a common external tooth for both the first external tooth 26 (a tooth that meshes with the first internal tooth 33 on the inner circumference of the first internal gear 21) and the second external tooth 27 (a tooth that meshes with the second internal tooth 34 on the inner circumference of the second internal gear 22). This makes it possible to reduce the machining cost of the external gear 20 compared to providing the first external tooth 26 and the second external tooth 27 as separate external teeth with different numbers of teeth.

[0069] Furthermore, this steering stopper device 1 sets the reduction ratio of the external gear 20 and the first internal gear 21 shown in Figure 2 to i １ The reduction ratio of the external gear 20 and the second internal gear 22 is set to i ２ When this is the case, (1 / i １ ) and (1 / i ２ The number of teeth on the first internal gear 33 and the second internal gear 34 are set so that the absolute value of the difference between them is 1 / 10 or less (preferably 1 / 20 or less), resulting in a small difference in rotational speed between the first internal gear 21 and the second internal gear 22. Therefore, it is possible to reliably set the position in which the rotation of the steering wheel 2 shown in Figure 1 is restricted to an angular range exceeding 360°.

[0070] Furthermore, as shown in Figures 2 to 4, the steering stopper device 1 is arranged such that the first internal gear 21 and the second internal gear 22 are eccentrically positioned in the same direction (upward in the figures) with respect to the rotation center of the external gear 20. As a result, when viewed from the axial direction, most of the first internal gear 21 and most of the second internal gear 22 overlap, making it compact in the radial direction.

[0071] Furthermore, as shown in Figure 2, the steering stopper device 1 has a housing 23 that accommodates the first internal gear 21 and the second internal gear 22, which is divided axially into a first divided housing 23A that accommodates the first internal gear 21 and a second divided housing 23B that accommodates the second internal gear 22, making it easy to assemble the first internal gear 21 and the second internal gear 22.

[0072] In the above embodiment, an example was described in which the steering stopper device 1 is attached to the motor shaft 16 of the reaction motor 7, as shown in Figures 1 and 2. However, the steering stopper device 1 may also be attached directly to the steering shaft 5 as shown in Figure 1.

[0073] Furthermore, in the above embodiment, as an example of a steering device according to the present invention, a vehicle steering device that steers a pair of left and right steering wheels 4 of a vehicle was described as shown in Figure 1. However, this invention is not limited to vehicles, but can be similarly applied to other vehicles such as ships, construction machinery, agricultural machinery, all-terrain vehicles, and multi-purpose four-wheeled vehicles, which change the direction of the steering target by operating a steering actuator 3 in accordance with the amount of rotation of the steering wheel 2.

[0074] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended.

[0075] 1 Steering stopper device 2 Steering wheel 20 External gear 21 First internal gear 22 Second internal gear 23 Housing 23A First split housing 23B Second split housing 26 First external tooth 27 Second external tooth 33 First internal tooth 34 Second internal tooth 35 First housing hole 36 Second housing hole 40 Stopper projection 41 Circumferential groove 42 Stopper receiving part

Claims

1. An external gear (20) having a plurality of first external teeth (26) arranged in the circumferential direction and a plurality of second external teeth (27) arranged in the circumferential direction adjacent to the first external teeth (26) in the axial direction on its outer circumference; an annular first internal gear (21) having a plurality of first internal teeth (33) on its inner circumference that mesh with the first external teeth (26); and an annular second internal gear (22) arranged adjacent to the first internal gear (21) in the axial direction and having a plurality of second internal teeth (34) on its inner circumference that mesh with the second external teeth (27); the reduction ratio i of the external gear (20) and the first internal gear (21) obtained by dividing the number of teeth of the first internal teeth (33) by the number of teeth of the first external teeth (26) １ However, the reduction ratio i between the external gear (20) and the second internal gear (22) obtained by dividing the number of teeth of the second internal gear (34) by the number of teeth of the second external gear (27) ２ Unlike the above, the first internal gear (21) is provided with a stopper projection (40) that rotates integrally with the first internal gear (21), and the second internal gear (22) is provided with a stopper receiving portion (42) that rotates integrally with the second internal gear (22), and the steering stopper device restricts the rotation angle of the steering wheel (2) by the stopper projection (40) contacting the stopper receiving portion (42) in the circumferential direction.

2. The steering stopper device according to claim 1, wherein the stopper projection (40) is a projection provided that protrudes from the axial end face of the first internal gear (21) on the side of the second internal gear (22) toward the second internal gear (22), the axial end face of the second internal gear (22) on the side of the first internal gear (21) is provided with a circumferential groove (41) that movably accommodates the stopper projection (40) in the circumferential direction and extends in the circumferential direction within an angular range of less than 360°, and the stopper receiving portion (42) is the circumferential end face of the circumferential groove (41).

3. The steering stopper device according to claim 1 or 2, wherein a plurality of external teeth are arranged circumferentially on the outer circumference of the external gear (20), extending axially from the portion surrounded by the first internal gear (21) to the portion surrounded by the second internal gear (22), the first external tooth (26) is the portion of each external tooth on the side of the first internal gear (21), and the second external tooth (27) is the portion of each external tooth on the side of the second internal gear (22).

4. (1 / i １ ) and (1 / i ２ The reduction ratio i of the external gear (20) and the first internal gear (21) is set such that the absolute value of the difference between them is 1 / 10 or less. １ The reduction ratio i of the external gear (20) and the second internal gear (22) ２ A steering stopper device according to claim 1 or 2, wherein the following is set.

5. The steering stopper device according to claim 1 or 2, wherein the first internal gear (21) and the second internal gear (22) are arranged eccentrically in the same direction with respect to the rotation center of the external gear (20).

6. The steering stopper device according to claim 1 or 2, further comprising a housing (23) for housing the first internal gear (21) and the second internal gear (22), wherein the housing (23) is axially connected to a first divided housing (23A) having a cylindrical first housing hole (35) for housing the first internal gear (21) and a second divided housing (23B) having a cylindrical second housing hole (36) for housing the second internal gear (22) with its center eccentric to the center of the first housing hole (35).

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