Rotation transmission device

Abstract

The invention relates to a rotation transmission device. A rotation transmission device (100) is provided with an input member (110), an intermediate member (120), an output member (130), a first biasing member (210), a cam mechanism (300), and a housing (101). The first biasing member (210) connects the intermediate member (120) and the output member (130), and biases the intermediate member (120) toward the input member (110). The intermediate member (120) has an intermediate main body section (121), a rotary friction section (125), and a second biasing member (220). The rotary friction part (125) is disposed at a position facing the fixed friction surface (109). The second biasing member (220) connects the intermediate body section (121) and the rotary friction section (125), and biases the rotary friction section (125) toward the fixed friction surface (109). The elastic coefficient of the first biasing member (210) is greater than the elastic coefficient of the second biasing member (220).

Description

Technical Field

[0001] This invention relates to a rotary transmission device. Background Technology

[0002] Previously, there was a device that transmitted rotational force from a drive source such as a motor to a specified object, which was configured to cut off the input (reverse input) of the rotational force (torque) transmitted from the object toward the drive source.

[0003] For example, Patent Document 1 discloses a power transmission mechanism for a drive system in an automobile. In this power transmission mechanism, when the input-side component rotates due to input rotational power from a drive source, a portion of this input rotational power is converted into an axial force through the engagement of a generally V-shaped concave cam and a convex cam, causing the intermediate component to overcome the spring force and move axially toward the output side. Furthermore, the friction clutch is released by the axial displacement of the intermediate component toward the output side, allowing the intermediate component to rotate relative to the stationary component. On the other hand, if the drive source stops, the intermediate component moves axially toward the input side due to the pressing force of the spring, the friction clutch actuates, and the intermediate component is restricted in the rotational direction relative to the stationary component.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2000-346099

[0005] In the aforementioned existing power transmission mechanism, the intermediate component has a sliding spline hole on its inner circumference. This sliding spline hole engages with a sliding spline formed on the outer circumference of the output-side component, allowing for axial movement while preventing rotation relative to the output-side component. Therefore, when the intermediate component moves axially relative to the output-side component, friction inevitably occurs between them. This results in a reduction in torque transmission efficiency. Summary of the Invention

[0006] The present invention was made by the inventors of this application, who refocused on the above-mentioned problems, and the purpose is to provide a rotary transmission device that can suppress the reduction of torque transmission efficiency.

[0007] A rotary transmission device according to one embodiment of the present invention includes: an input member that rotates about a central axis extending in a first direction by a torque input from a drive source; an intermediate member that is coaxially disposed with the input member on one side of the input member in the first direction; an output member that is coaxially disposed with the input member and the intermediate member on one side of the intermediate member in the first direction; a first force-applying member that connects the intermediate member and the output member and applies force to the intermediate member toward the input member; a cam mechanism disposed between the input member and the intermediate member and transmitting the rotation of the input member to the intermediate member; and a housing that houses the intermediate member and the cam mechanism, holding the input member and the output member rotatable. The intermediate component has a fixed friction surface and includes: an intermediate main body disposed at a position through which the central axis passes and a first force-applying component fixed thereon; a rotating friction part disposed at a position facing the fixed friction surface in the first direction; and a second force-applying component connecting the intermediate main body and the rotating friction part and applying force to the rotating friction part toward the fixed friction surface. The elastic coefficient of the first force-applying component is greater than that of the second force-applying component. When the input component rotates, the cam mechanism maintains the state of transmitting the rotation of the input component to the intermediate main body and moves the intermediate main body toward a direction close to the output component, while the rotating friction part moves away from the fixed friction surface via the second force-applying component.

[0008] The rotary transmission device according to the present invention can suppress the reduction of torque transmission efficiency. Attached Figure Description

[0009] Figure 1 This is a schematic diagram showing the steering control device and its surrounding structure in an embodiment.

[0010] Figure 2 This is a cross-sectional view showing the structural outline of the rotary transmission device according to the embodiment.

[0011] Figure 3 This is an exploded perspective view of the rotary transmission device according to the embodiment.

[0012] Figure 4 This is an exploded perspective view of the intermediate components of the implementation method.

[0013] Figure 5 This is a perspective view showing the appearance of the input component and the first cam portion in the embodiment.

[0014] Figure 6 This is a first partial cross-sectional view of the rotary transmission device according to the embodiment.

[0015] Figure 7 This is a second-part cross-sectional view of the rotary transmission device according to the embodiment. Detailed Implementation

[0016] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the embodiments described below are merely general or specific examples. The numerical values, shapes, materials, structural members, their arrangement, connection methods, and manufacturing sequence shown in the following embodiments are only examples and are not intended to limit the present invention. Additionally, in the structural members of the following embodiments, structural members not described in the independent technical solutions representing the highest-level concept are described as arbitrary structural members.

[0017] The accompanying drawings are schematic diagrams with appropriate emphasis, omission, or ratio adjustments for the purpose of illustrating the invention, and may sometimes differ from the actual shapes, positional relationships, and ratios. Furthermore, in the following embodiments and technical solutions, parallel and orthogonal representations are often used to indicate relative directions or postures, but strictly speaking, these representations also include cases where the direction or posture is not that described. For example, the case of two parallel directions does not only refer to the two directions being completely parallel, but rather to a case where they are actually parallel, i.e., containing, for example, a difference of about a few percent.

[0018] (Implementation Method)

[0019] [1. Structural overview of the steering control device]

[0020] use Figure 1 The overall structure of the steering control device 10 in this embodiment will be described. Figure 1 This is a schematic diagram showing the steering control device 10 and its surrounding structure according to the embodiment. Figure 1 In the figure, regarding the rotary transmission device 100, a cross-section of the XZ plane through the central axis Sa of the input component 110 is shown, and regarding the wheel 202, its approximate shape is shown with dotted lines. Figure 1 For the sake of simplicity in the illustration of the steering control device 10, the illustration of the axle suspension mechanism (shock absorber and arm, etc.) supporting the wheel 202 is omitted.

[0021] The steering control device 10 is a device that steers a vehicle by turning the wheels 202 according to the movement of the steering wheel 15 operated by the driver. The steering control device 10 includes the rotation transmission device 100 of this embodiment.

[0022] The steering control device 10 includes: a motor 190 that generates a driving force for steering the wheels 202; a rotary transmission device 100 that transmits the driving force of the motor 190 to the wheels 202 and operates in a manner that cuts off or inhibits reverse input from the wheels 202; and a reducer 180.

[0023] The rotary transmission device 100 includes an input component 110, an intermediate component 120, an output component 130, a cam mechanism 300, and a housing 101. The input component 110 rotates about a central axis Sa via an input from a drive source, i.e., a motor 190. The torque generated by the rotation of the input component 110 is transmitted to the output component 130 via the cam mechanism 300 and the intermediate component 120, thereby causing the output component 130 to rotate. In this embodiment, the input component 110, the intermediate component 120, and the output component 130 are configured to rotate about the central axis Sa. That is, the input component 110, the intermediate component 120, and the output component 130 are arranged coaxially. In this embodiment, the central axis Sa is an imaginary axis parallel to the Z-axis direction. Figures 1 to 7 Although the Z-axis direction is shown in the diagram as being consistent with the vertical direction, it does not actually need to be consistent with the vertical direction. For detailed information on the rotary transmission device 100, please refer to [link / reference needed]. Figures 2-7 This will be discussed later.

[0024] The torque generated by the rotation of the output component 130 of the rotation transmission device 100 is input to the reducer 180, from which a lower-speed rotation and a larger torque are output. The reducer 180 is connected to the support shaft 181 supporting the wheel 202, and the support shaft 181 rotates about the central axis Sb by the torque output from the reducer 180. As a result, the wheel 202 turns.

[0025] More specifically, in this embodiment, the wheel 202 is driven by a drive motor (not shown) mounted on a centrally located wheel hub bracket 80, thereby driving the vehicle equipped with the steering control device 10. The wheel hub bracket 80 is fixed to the support axle 181, and the wheel 202 receives the rotational driving force of the reducer 180 via the wheel hub bracket 80 and the support axle 181. As a result, the wheel 202 steers.

[0026] In addition, Figure 1In the diagram, the central axis Sb of the support shaft 181 supporting the wheel 202 is shown to be parallel to the vertical direction (Z-axis direction), but the central axis Sb does not need to be parallel to the vertical direction. For example, to increase the contact area between the wheel 202 and the road surface when the vehicle passes through a curve, the central axis Sb can also be set to be inclined inward (opening outward the closer to the road surface). That is, the camber angle of the wheel 202 can also be negative. In this case, the central axis Sa of the input component 110 can be parallel to the central axis Sb of the support shaft 181 (including the case of being on the same straight line) or parallel in the vertical direction. When the central axis Sb and the central axis Sa are not parallel, a universal joint can be provided between the reducer 180 and the support shaft 181. In addition, although in Figure 1 Not shown in the diagram, but for example, the central axis Sb of the support shaft 181 can also tilt further back (towards the positive Z-axis and the positive Y-axis) the further away from the road surface when viewed from the X-axis direction. That is, the caster angle of the wheel 202 can also be greater than 0°.

[0027] The steering control device 10 configured in this way is operated under the control of a higher-level ECU (Electronic Control Unit) 30. Specifically, for example, if the driver turns the steering wheel 15, the rotation angle and angular velocity of the shaft connected to the steering wheel 15 are detected by the steering angle sensor 20. The detection result of the steering angle sensor 20 is sent to the higher-level ECU 30, which then sends a control signal based on the detection result to the steering ECU 40. The steering ECU 40 controls the motor 190 according to the received control signal. As a result, the wheel 202 turns in a manner that changes the steering angle. Such a system is, for example, called a SBW (Steer By Wire) system. Furthermore, although various information such as the detection result of the vehicle speed sensor is input to the higher-level ECU 30, the details of the processing performed by the higher-level ECU 30 are omitted.

[0028] exist Figure 1 Although the diagram shows the right front wheel (wheel 202) and its surrounding structure among the four wheels 202 of the vehicle, in this embodiment, at least the left front wheel among the other three wheels 202 is also equipped with a motor 190, a rotation transmission device 100, and a driving motor. That is, in this embodiment, at least two wheels 202 each have a driving force independent of the other wheels and can be steered independently of the other wheels.

[0029] Thus, in the steering control device 10, each of the left and right front wheels (wheels 202) is steered by the driving force of an electrically operated motor 190. Therefore, compared with the existing structure that uses a linkage mechanism to steer the left and right front wheels synchronously, it has advantages such as improved effective utilization of interior space, greater freedom of steering angle of the front wheels, or improved vehicle handling performance resulting from independent steering of the left and right front wheels.

[0030] However, in steering systems that use motors to independently steer the left and right wheels, maintaining the steering angle of the front wheels becomes a problem, especially when the vehicle is stationary. This is particularly problematic when the kingpin inclination angle is not 0° and the tire wear radius is not 0mm, and / or the caster angle is not 0° and the trail is not 0mm. Furthermore, during vehicle operation, maintaining the steering angle of the front wheels also becomes a problem by overcoming the torque generated when the front wheels are lifted off the road (lift torque) or vibrations experienced by the steering system. To address these issues, electrically operated devices (such as electromagnetic brakes) for maintaining the steering angle of the front wheels have been considered. However, in such cases, the device continues to consume electricity even when the vehicle is stationary, leading to a reduction in the vehicle's battery capacity.

[0031] Therefore, the rotary transmission device 100 of this embodiment has a structure that can mechanically suppress changes in the steering angle during periods when there is no torque input (positive input) from the motor 190, and a structure that can suppress the reduction in torque transmission efficiency. The rotary transmission device 100 of this embodiment will be described in more detail below.

[0032] [2. Details of the rotary transmission device]

[0033] Figure 2 This is a cross-sectional view showing the structural outline of the rotary transmission device 100 according to the embodiment. Figure 3 This is an exploded perspective view of the rotary transmission device 100 according to the embodiment. Figure 4 This is an exploded perspective view of the intermediate component 120 in the embodiment. Figures 2-4 The diagram shows bolts used to fasten various components. Although these bolts include bolts of different sizes and shapes, for the sake of simplicity, each of these bolts is labeled "bolt 700".

[0034] Figure 5 This is a perspective view showing the appearance of the input component 110 and the first cam portion 310 in the embodiment. Figure 6 This is a first partial cross-sectional view of the rotary transmission device 100 according to the embodiment. Figure 7 This is a second-part cross-sectional view of the rotary transmission device 100 according to the embodiment. Figure 6The diagram schematically illustrates a cross-section of the intermediate component 120 and its surrounding components in a state where no torque from the motor 190 is input to the rotary transmission device 100 (stopped state). Figure 7 The diagram schematically illustrates a cross-section of the intermediate component 120 and its surrounding components in a state (operational state) where torque from the motor 190 is input to the rotary transmission device 100. Figure 6 as well as Figure 7 The diagram of bolts 700 and other components used to fix the various parts is omitted.

[0035] like Figures 1-5 As shown, the rotation transmission device 100 of this embodiment includes: a housing 101 fixed to the vehicle, an intermediate component 120 and a cam mechanism 300 housed in the housing 101, an input component 110 and an output component 130 held in place by the housing 101 to be rotatable, and a first force-applying component 210 connecting the intermediate component 120 and the output component 130.

[0036] The housing 101 has: a housing body 101a for housing the intermediate component 120, etc.; and a housing cover 101b fixed to the housing body 101a with an opening in the direction of the output shaft 139 protruding. The housing cover 101b is fixed to the housing body 101a using bolts or the like (not shown).

[0037] The input component 110 is a rotatable component supported by an input bearing 420 disposed in the housing 101. In this embodiment, the input bearing 420 is an angular contact ball bearing capable of simultaneously supporting radial and axial loads. The input component 110 has a mounting hole 110a into which the shaft of the motor 190, i.e., the motor shaft 191, is inserted and fixed. Thus, the input component 110 receives torque input from the motor 190 and rotates about its central axis Sa.

[0038] like Figure 3 as well as Figure 4 As shown, the intermediate component 120 includes: an intermediate main body 121 disposed at a position through which the central axis Sa passes; an annular rotating friction portion 125 when viewed axially; and a second force-applying component 220 connecting the intermediate main body 121 and the rotating friction portion 125. "Axial direction" refers to the direction of the central axis Sa, which in this embodiment is a direction parallel to the Z-axis direction. The Z-axis direction is an example of a first direction. That is, the central axis Sa is an imaginary axis extending along the first direction. Hereinafter, the direction of rotation centered on the central axis Sa will be referred to as the "circumferential direction," and the direction of a straight line orthogonal to and passing through the central axis Sa will be referred to as the "radial direction." The radial direction is an example of a second direction.

[0039] In the intermediate component 120, the second force-applying component 220 applies force to the rotating friction portion 125 toward the fixed friction surface 109 of the housing 101. In this embodiment, the housing 101 has an annular fixed friction portion 108, which is viewed from the axial direction, at a position opposite to the rotating friction portion 125 along the Z-axis. The surface of the fixed friction portion 108 in the negative Z-axis direction functions as the fixed friction surface 109.

[0040] More specifically, the intermediate component 120 has an intermediate main body 121 disposed at the center of the annular rotating friction portion 125, and a second force-applying component 220 is disposed to connect the intermediate main body 121 and the rotating friction portion 125. In this embodiment, a leaf spring, which is an example of a plate-shaped elastic component, is used as the second force-applying component 220. The second force-applying component 220 is disposed in an orientation such that its thickness direction is oriented towards the Z-axis direction.

[0041] In more detail, Figure 4 As shown, the second force-applying member 220 has a second fixing portion 222 fixed to the intermediate main body portion 121, and a plurality of second connecting portions 221 extending radially outward from the second fixing portion 222. In this embodiment, the second force-applying member 220 is provided with a circumferentially Cd (refer to...) Figure 5 Three second connecting portions 221 are arranged at equal intervals on the intermediate main body 121. The second fixing portion 222 is fixed to the intermediate main body 121 by screwing in the screw holes 121b of the three through holes 222a of the second fixing portion 222. Furthermore, each of the three second connecting portions 221 is fixed to the rotating friction portion 125 by screwing in the screw holes 125a of the rotating friction portion 125 through the through holes 221a of each of the three second connecting portions 221. Thus, the intermediate main body 121 and the rotating friction portion 125 are connected by the second force-applying member 220. When the rotation transmission device 100 is in a stopped state, the second force-applying member 220 applies force to the rotating friction portion 125 toward the fixed friction surface 109. That is, the rotating friction portion 125 is pressed against the fixed friction surface 109.

[0042] The output component 130 is a rotatable component supported by an output bearing 410 disposed in the housing 101. In this embodiment, the output bearing 410 is the same angular contact ball bearing as the input bearing 420. Figure 2 as well as Figure 3As shown, the output component 130 includes a disc-shaped output main body 131 and an output shaft 139 protruding from the output main body 131 in the negative Z-axis direction. In this embodiment, although the output shaft 139 is integrally formed with the output main body 131, the output shaft 139 can also be a component independent of the output main body 131. When the output shaft 139 is a component independent of the output main body 131, examples of means for joining the output shaft 139 and the output main body 131 include welding, pressing, or fastening based on bolts and nuts, or combinations thereof. In this embodiment, as... Figure 2 as well as Figure 3 As shown, the output bearing 410 is fixed between the bearing retaining member 450 and the output main body 131 by four bolts 700 fastened to the housing cover 101b by the bearing retaining member 450.

[0043] The output main body 131 is the portion that receives the torque generated by the rotation of the intermediate member 120. Specifically, the intermediate member 120 and the output main body 131 are connected by a first force-applying member 210. The output main body 131 receives the torque generated by the rotation of the intermediate member 120 via the first force-applying member 210, thereby causing the output main body 131 and the output shaft 139 (i.e., the output member 130) to rotate about the central axis Sa. In this embodiment, a leaf spring is used as an example of a plate-shaped elastic member as the first force-applying member 210. The first force-applying member 210 is configured with its thickness direction oriented towards the Z-axis direction.

[0044] More specifically, such as Figure 3 As shown, the first force-applying component 210 has: a first fixing portion 212 fixed to the intermediate main body portion 121, and a plurality of first connecting portions 211 extending radially outward from the first fixing portion 212. In this embodiment, the first force-applying component 210 is provided with two first connecting portions 211 extending in opposite directions from the first fixing portion 212. The first fixing portion 212 is connected by a through gasket 140 (see reference). Figure 2 as well as Figure 3 The bolt 700, in a state of [condition], is fixed to the intermediate main body 121. Specifically, the bolt 700, which passes through the through hole 140a in the gasket 140 and the through hole 212a in the first fixing part 212, is fixed to the screw hole 121a in the intermediate main body 121 (see [reference]). Figure 2The first fixing part 212 is thus fixed to the intermediate main body 121. In this embodiment, there are four such through holes 140a and through holes 212a. That is, in this embodiment, the gasket 140 and the first fixing part 212 are fastened together to the intermediate main body 121 by four bolts 700. Thus, the gasket 140 and the first fixing part 212 are fixed to the intermediate main body 121. Furthermore, the bolts 700, which are in the state of passing through the through holes 131a of the output main body 131, are inserted into each of the two through holes 211a provided in the two first connecting parts 211, and screwed with the nuts 710 (see reference). Figure 3 Thus, each of the two first connecting parts 211 is fixed to the output main body part 131. As a result, the output part 130 and the intermediate part 120 are connected by the first force-applying part 210.

[0045] The first force-applying component 210 configured in this way can apply force to the intermediate component 120 toward the input component 110 regardless of whether the rotary transmission device 100 is in a stopped state or in an active state.

[0046] In the rotary transmission device 100 configured as described above, a cam mechanism 300 is disposed between the input member 110 and the intermediate member 120. The cam mechanism 300 is a mechanism that maintains the state of transmitting the rotation of the input member 110 to the intermediate main body 121 and moves the intermediate main body 121 toward the output member 130 (positive Z-axis direction). By moving the intermediate main body 121 toward the positive Z-axis direction via the cam mechanism 300, the rotary friction part 125, which is connected to the intermediate main body 121 and the second force-applying member 220, moves toward the direction away from the fixed friction surface 109. That is, the friction between the rotary friction part 125 and the fixed friction surface 109 can be reduced, thereby enabling the intermediate member 120 to rotate efficiently using the torque received from the input member 110.

[0047] Specifically, the cam mechanism 300 of this embodiment has a first cam portion 310 and a second cam portion 320. The first cam portion 310 is provided at the end of the input member 110 in the negative Z-axis direction. The second cam portion 320 is provided at the end of the intermediate main body 121 in the positive Z-axis direction. In this embodiment, the first cam portion 310 is integrally provided with the input member 110, so it can also be said that a part of the input member 110 is the first cam portion 310. Similarly, the second cam portion 320 is integrally provided with the intermediate main body 121, so it can also be said that a part of the intermediate main body 121 is the second cam portion 320. That is, it can also be said that the cam mechanism 300 is composed of a part of the input member 110 and a part of the intermediate main body 121.

[0048] like Figure 5As shown, the first cam portion 310 has three concave cams 311 that are recessed in the positive Z-axis direction. Figure 4 As shown, the second cam portion 320 has three convex cams 321 protruding in the positive Z-axis direction. Three concave cams 311 correspond one-to-one with the three convex cams 321. The concave cams 311 along the circumferential direction Cd (refer to...) Figure 5 The cross-section of the cam 321 is a roughly triangular concave portion. The cross-section of the cam 321 along the circumferential direction Cd is a roughly triangular convex portion. When the cam 321 is inserted into the interior of the concave cam 311 of this shape, and the concave cam 311 is moved circumferentially Cd relative to the cam 321, the inner surface of the concave cam 311 and the outer surface of the cam 321 contact and slide. As a result, the component force in the direction that causes the cam 321 to move away from the concave cam 311 acts on the cam 321.

[0049] In the cam mechanism 300 configured in this way, when the rotary transmission device 100 is in a stopped state, such as Figure 6 As shown, the cam 321 is inserted into the concave cam 311. Specifically, the cam 321 receives a force from the first force-applying member 210 via the intermediate body portion 121 and is subjected to a force in a direction close to the input member 110. In this state, since no power is input to the motor 190 for output torque, the input member 110, to which the motor shaft 191 is fixed, can actually rotate about the central axis Sa. Therefore, the input member 110 rotates such that the inner surface of the concave cam 311 follows the outer surface of the cam 321. For example, Figure 7 The input component 110, as shown in the diagram, rotates to the indicated rotation position. Figure 6 The rotational position is shown. Furthermore, in Figure 6 as well as Figure 7 In order to clarify the structural relationship between the concave cam 311 and the convex cam 321, a simple and schematic diagram of the concave cam 311 and the convex cam 321 is provided.

[0050] Cam mechanism 300 Figure 6 In the illustrated state, the intermediate main body 121 is subjected to a force from the first force-applying member 210, pressing the input member 110 in the positive Z-axis direction. In this embodiment, as described above, the input bearing 420 supporting the input member 110 for rotation is an angular contact ball bearing. Figure 6 as well as Figure 7As shown, the input bearing 420 is configured to support a load in the positive Z-axis direction. That is, in this embodiment, a preload can be applied to the angular contact ball bearing, i.e., the input bearing 420, by the force of the first force-applying member 210. This suppresses loosening of the input member 110. In this state, the rotating friction portion 125, connected to the intermediate main body 121 via the second force-applying member 220, is pressed against the fixed friction surface 109 by the force from the second force-applying member 220.

[0051] More specifically, in this embodiment, the elastic modulus of the first force-applying member 210 is greater than that of the second force-applying member 220. Therefore, the intermediate main body 121 is subjected to the force of the first force-applying member 210, for example from... Figure 7 Move to the position shown Figure 6 In the position shown, after the rotating friction part 125 contacts the fixed friction surface 109, the second force-applying member 220 can be deformed and moved to the position shown. Figure 6 The position is shown. Therefore, the surface of the rotating friction part 125 in the positive Z-axis direction, i.e., the rotating friction surface 125b, is pressed against the fixed friction surface 109. That is, the intermediate main body 121 simultaneously presses the input member 110 in the positive Z-axis direction and presses the rotating friction part 125 against the fixed friction surface 109. In this case, the frictional force between the rotating friction part 125 and the fixed friction surface 109 is maintained at a relatively high level, resulting in the suppression of rotation of the intermediate member 120 about the central axis Sa. Therefore, even if the output shaft 139 of the output member 130 receives a torque input (reverse input) from the wheel 202 side, the rotation of the intermediate member 120 caused by the reverse input is suppressed. That is, the change in the steering angle of the wheel 202 is suppressed.

[0052] When the rotary transmission device 100 changes from a stopped state to an operating state, that is, when the input component 110 receives a torque input from the motor 190, such as Figure 7 As shown, the input component 110 rotates clockwise, for example, when viewed from the positive Z-axis direction. In this case, the concave cam 311 also rotates clockwise along with the input component 110. Thus, as Figure 7 As shown, the inner surface of the concave cam 311 slides against the outer surface of the convex cam 321, and the convex cam 321 receives a force in the negative Z-axis direction from the concave cam 311. As a result, the intermediate main body 121 moves away from the input component 110, overcoming the force from the first force-applying member 210. Accompanyingly, the force from the second force-applying member 220 on the rotating friction part 125 connected to the intermediate main body 121 via the second force-applying member 220 weakens. Therefore, the friction between the rotating friction part 125 and the fixed friction surface 109 is reduced. For example, as... Figure 7As shown, the rotating friction part 125 separates from the fixed friction surface 109. As a result, the frictional force becomes zero. Therefore, the intermediate part 120 is able to rotate about the central axis Sa without being subjected to frictional resistance caused by the fixed friction surface 109.

[0053] Thus, with the frictional force between the rotating friction part 125 and the fixed friction surface 109 reduced, the concave cam 311 and the convex cam 321 are maintained in an engaged state in the rotational direction (i.e., circumferential Cd) of the input member 110. Specifically, in this embodiment, the movement of the intermediate main body 121 in the negative Z-axis direction is restricted by the contact between the shim 140 disposed in the negative Z-axis direction of the intermediate main body 121 and the output member 130. As a result, the maximum deformation of the first force-applying member 210 can be suppressed, and the extension of the convex cam 321 outward from the concave cam 311 is restricted, i.e., the convex cam 321 is restricted from disengaging from the concave cam 311. As a result, for example, Figure 7 As shown, the first cam portion 310 and the second cam portion 320 are maintained in a state of engagement on the circumferential Cd. Therefore, the torque generated by the rotation of the input member 110 is transmitted to the intermediate member 120 via the cam mechanism 300. At this time, the friction between the rotating friction portion 125 and the fixed friction surface 109 is reduced, so the intermediate member 120 can start rotating with a relatively low input torque. Then, since the rotating friction portion 125 separates from the fixed friction surface 109 and the friction becomes zero, as a result, the intermediate member 120 can rotate efficiently with the torque input from the input member 110.

[0054] The output component 130, connected to the intermediate component 120 via the first force-applying component 210, rotates due to the torque generated by the rotation of the intermediate component 120. The torque generated by the rotation of the output shaft 139 of the output component 130 is converted into a larger torque by the reducer 180 and transmitted to the support shaft 181. As a result, the support shaft 181 rotates about the central axis Sb, thereby steering the wheel 202.

[0055] When the rotary transmission device 100 is in operation, the input component 110 applies a negative Z-axis force to the intermediate main body 121 and receives a reaction force from the first force-applying component 210 via the intermediate main body 121. Therefore, even when the rotary transmission device 100 is in operation, the first force-applying component 210 can apply preload to the angular contact ball bearing, i.e., the input bearing 420. As a result, the input component 110 can rotate more stably.

[0056] In the rotary transmission device 100 configured as described above, the input component 110, intermediate main body 121, rotary friction part 125, gasket 140, output component 130, and housing 101 are made of metals such as iron or aluminum alloy. The rotary friction part 125 and the fixed friction part 108 forming the fixed friction surface 109 are made of, for example, a material used for brake pads to increase friction during contact. In this embodiment, the first force-applying component 210 and the second force-applying component 220 of the leaf spring are made of, for example, carbon tool steel such as SK85 as specified in Japanese Industrial Standard (JIS) G4401.

[0057] The structure of the cam mechanism 300 in this embodiment will be described as follows. The cam mechanism 300 includes a first cam portion 310 disposed at one end of the input member 110 in the Z-axis direction, and a second cam portion 320 disposed at the other end of the intermediate main body portion 121 in the Z-axis direction. The first cam portion 310 and the second cam portion 320 have the following shape: when the input member 110 rotates, the intermediate main body portion 121 moves toward the output member 130, and in the state where the intermediate main body portion 121 is closest to the output member 130, the rotational direction of the input member 110 can be maintained.

[0058] [3. Summary of Implementation Methods]

[0059] The technical features of the rotary transmission device 100 of this embodiment described above will be explained, for example, as follows (1) to (5).

[0060] (1) The rotation transmission device 100 of this embodiment includes: an input member 110, an intermediate member 120, an output member 130, a first force-applying member 210, a cam mechanism 300, and a housing 101. The input member 110 rotates about a central axis Sa extending in the Z-axis direction by a torque input from a drive source (in this embodiment, a motor 190). The intermediate member 120 is coaxially disposed with the input member 110 on one side of the input member 110 in the Z-axis direction. The output member 130 is coaxially disposed with the input member 110 and the intermediate member 120 on one side of the intermediate member 120 in the Z-axis direction. The first force-applying member 210 connects the intermediate member 120 and the output member 130, and applies a force to the intermediate member 120 toward the input member 110. The cam mechanism 300 is disposed between the input member 110 and the intermediate member 120, and transmits the rotation of the input member 110 to the intermediate member 120. The housing 101 houses the intermediate component 120 and the cam mechanism 300, and holds the input component 110 and the output component 130 in a rotatable position, and has a fixed friction surface 109. The intermediate component 120 has an intermediate main body 121, a rotating friction part 125, and a second force-applying component 220. The intermediate main body 121 is positioned where the central axis Sa passes through, and is fixed by the first force-applying component 210. The rotating friction part 125 is positioned opposite the fixed friction surface 109 in the Z-axis direction. The second force-applying component 220 applies force to the intermediate main body 121 and the rotating friction part 125, and applies force to the rotating friction part 125 toward the fixed friction surface 109. The elastic modulus of the first force-applying component 210 is greater than that of the second force-applying component 220. When the input member 110 rotates, the cam mechanism 300 maintains the state of transmitting the rotation of the input member 110 to the intermediate main body 121 and moves the intermediate main body 121 toward the output member 130. Simultaneously, the rotating friction part 125 is moved away from the fixed friction surface 109 via the second force application member 220. In this embodiment, one side of the Z-axis direction is the negative Z-axis direction, and the other side of the Z-axis direction is the positive Z-axis direction. This is also true below.

[0061] According to the rotary transmission device 100 described in (1) above, when the input member 110 rotates, the cam mechanism 300 can overcome the force of the first force-applying member 210, causing the intermediate main body 121 to move toward the output member 130. As a result, the friction between the rotating friction part 125, connected to the intermediate main body 121 via the second force-applying member 220, and the fixed friction surface 109 is reduced. Consequently, the rotation of the input member 110 is efficiently transmitted to the output member 130 via the intermediate main body 121 and the first force-applying member 210. In this series of actions, the intermediate main body 121 moves toward the direction of the central axis Sa (Z-axis direction) while supported by the first force-applying member 210. Therefore, unlike the case where the intermediate main body 121 slides relative to the output member 130, the contact and separation of the rotating friction part 125 and the fixed friction surface 109 can be switched without generating friction between the intermediate main body 121 and the output member 130. Thus, the reduction in torque transmission efficiency is suppressed.

[0062] Furthermore, the rotating friction part 125 is connected to the intermediate main body part 121 via the second force-applying member 220. Therefore, the position of the rotating friction part 125 relative to the intermediate main body part 121 in the Z-axis direction is variable (see reference). Figure 6 as well as Figure 7 More specifically, the elastic coefficient of the first force-applying component 210 is greater than that of the second force-applying component 220. Therefore, the simultaneous existence of the state where the intermediate main body 121 presses the input component 110 in the positive Z-axis direction and the state where the rotating friction part 125 is pressed against the fixed friction surface 109 can be easily achieved by the force from the first force-applying component 210. That is, by receiving the force from the first force-applying component 210 via the intermediate main body 121, the loosening of the input component 110 can be suppressed, and by the friction between the rotating friction part 125 and the fixed friction surface 109, the input (reverse input) of the rotational force (torque) transmitted from the output component 130 to the input component 110 can be cut off.

[0063] (2) The rotary transmission device 100 according to (1) above further includes: an angular contact ball bearing (input bearing 420), which is disposed on the other side of the input component 110 in the Z-axis direction between the input component 110 and the housing 101, and supports the input component 110 so that it can rotate relative to the housing 101 and cannot move in the Z-axis direction.

[0064] According to the rotary transmission device 100 described in (2) above, the angular contact ball bearing, i.e., the input bearing 420, can support the input component 110 so that it can rotate under a preload generated by the force from the first force-applying component 210. As a result, for example, loosening of the input component 110 can be more reliably suppressed, and the input component 110 can rotate efficiently.

[0065] (3) In the rotary transmission device 100 described in (1) or (2) above, the first force-applying member 210 is a plate-shaped elastic member that connects the intermediate main body 121 and the output member 130 in a second direction (radial) orthogonal to the Z-axis direction and has its thickness direction facing the Z-axis direction. In this embodiment, the first force-applying member 210 is a leaf spring.

[0066] According to the rotary transmission device 100 described in (3) above, the first force-applying component 210 can be implemented with a flat plate-shaped component, so for example, the increase in the dimension in the Z-axis direction caused by the first force-applying component 210 is suppressed.

[0067] (4) In the rotary transmission device 100 described in any one of (1) to (3) above, the second force-applying member 220 is a plate-shaped elastic member that connects the intermediate main body 121 and the rotary friction part 125 in a second direction orthogonal to the Z-axis direction and has its thickness direction facing the Z-axis direction. In this embodiment, the second force-applying member 220 is a leaf spring.

[0068] According to the rotary transmission device 100 described in (4) above, the second force-applying component 220 can be implemented with a flat plate-shaped component, so for example, the increase in the dimension in the Z-axis direction caused by the second force-applying component 220 is suppressed.

[0069] (5) The rotary transmission device 100 according to any one of (1) to (4) above further includes a gasket 140 disposed between the intermediate main body 121 and the output member 130. The intermediate main body 121 is in a state of mutual pressing with the output member 130 in the Z-axis direction via the gasket 140, thereby restricting the movement of the direction of approaching the output member 130.

[0070] According to the rotary transmission device 100 described in (5) above, the movement of the intermediate main body 121 toward the output member 130 is restricted, for example, suppressing the maximum deformation of the first force-applying member 210. Thus, damage or deterioration of the first force-applying member 210 is suppressed. Furthermore, the maximum movement of the intermediate main body 121 and the maximum deformation of the first force-applying member 210 can be adjusted, for example, by changing the thickness of the shim 140. That is, adjustment of the maximum deformation, etc., becomes easy.

[0071] (Other implementation methods)

[0072] The rotary transmission device of the present invention has been described above based on embodiments. However, the present invention is not limited to the above embodiments and modifications. Various modifications conceivable to those skilled in the art can be applied to the above embodiments to obtain forms, or forms constructed by combining multiple structural components described above, without departing from the spirit of the present invention, are also included within the scope of the present invention.

[0073] The shapes of the first force-applying component 210 and the second force-applying component 220 are not necessarily... Figure 3 as well as Figure 4 The shape shown. For example, the number of first connecting portions 211 provided by the first force-applying member 210 may be one or more. The number of second connecting portions 221 provided by the second force-applying member 220 may be two or less or four or more. However, from the viewpoint that the first force-applying member 210 applies a balanced force to the intermediate main body 121, it is preferable that the first force-applying member 210 provides a plurality of first connecting portions 211 arranged at equal intervals in the circumferential direction Cd. For example, from the viewpoint that the second force-applying member 220 applies a balanced force to the rotating friction portion 125, it is preferable that the second force-applying member 220 provides a plurality of second connecting portions 221 arranged at equal intervals in the circumferential direction Cd.

[0074] The first force-applying component 210 and the second force-applying component 220 can also be implemented by one or more elastic components other than leaf springs. For example, the first force-applying component 210 can also be implemented by one or more push springs that elastically deform along the Z-axis direction, which are arranged between the intermediate main body 121 and the output component 130, and the intermediate main body 121 and the output component 130 are connected by one or more push springs that elastically deform along the Z-axis direction. For example, the second force-applying component 220 can also be implemented by an elastic component other than leaf springs. For example, each of the intermediate main body 121 and the rotating friction part 125 can be provided with another part (opposing part) that is opposite to it in the Z-axis direction, and one or more push springs that elastically deform along the Z-axis direction can be arranged between these opposing parts. Even in any case, the contact and separation between the rotating friction part 125 and the fixed friction surface 109 can be switched when no frictional force is generated between the intermediate main body 121 and the output component 130. Furthermore, it is possible to easily achieve the coexistence of the state where the intermediate main body 121 presses the input component 110 in the positive Z-axis direction and the state where the rotating friction part 125 is pressed against the fixed friction surface 109.

[0075] The number of concave cams 311 in the first cam portion 310 and the number of convex cams 321 in the second cam portion 320 are not particularly limited. The first cam portion 310 only needs to have at least one concave cam 311, and the second cam portion 320 only needs to have at least one convex cam 321. However, from the viewpoint of transmitting a balanced torque along the circumferential direction Cd, it is preferable that the first cam portion 310 has N (two or more integers) concave cams 311 arranged at equal intervals along the circumferential direction Cd, and the second cam portion 320 has N convex cams 321 arranged at equal intervals along the circumferential direction Cd.

[0076] Crown gears may also be used for both the first cam portion 310 and the second cam portion 320. In this case, it can be explained that the recess between two adjacent teeth along the circumferential direction Cd in the first cam portion 310 is a concave cam 311. Furthermore, it can be explained that each of the teeth arranged at equal intervals along the circumferential direction Cd in the second cam portion 320 is a convex cam.

[0077] It is not necessary for the first cam portion 310 to have one or more concave cams 311 and the second cam portion 320 to have one or more convex cams 321. The first cam portion 310 may also have one or more convex cams and the second cam portion 320 may also have one or more concave cams.

[0078] The shapes of the convex cam 321 and the concave cam 311 are not limited to Figure 4 as well as Figure 5 The shapes shown are as follows. When one cam 321 presses the other along the circumferential direction Cd, the shapes of the cam 311 and the cam 321 can be whatever shape generates a component force in the pressing direction and a component force in the direction that causes one and the other to move away from each other along the axial direction.

[0079] It is not necessary for the motor shaft 191 to directly transmit torque to the input component 110. For example, torque can be transmitted from the motor 190 to the input component 110 by clamping one or more gears, belts, pulleys, etc., between the motor shaft 191 and the input component 110.

[0080] The rotary transmission device 100 of the embodiment can also be provided in a different type of device than the steering control device 10. For example, in a device that lifts an object by winding a steel wire through an output from a motor, the rotary transmission device 100 can also be used as a device for cutting off the force (reverse input) that pulls the steel wire on the object.

[0081] The steering control device 10 of the rotation transmission device 100 of the embodiment may not be a four-wheeled vehicle, for example, it may be used in a vehicle with three or more wheels.

[0082] Furthermore, any combination of two or more technical solutions from the multiple technical solutions described in the technical solution of this application, within the scope of technical non-contradiction, is also included in this invention.

[0083] Industrial applications

[0084] The rotary transmission device of the present invention is useful as a rotary transmission device for transmitting input from a motor to a specified object and for cutting off reverse input from the specified object. For example, it can be used as a rotary transmission device for vehicles such as automobiles, agricultural machinery or construction machinery.

[0085] Explanation of reference numerals in the attached figures

[0086] 10: Steering control device; 15: Steering wheel; 20: Steering angle sensor; 30: Upper ECU; 40: Steering ECU; 80: Wheel hub bracket; 100: Rotation transmission device; 101: Housing; 101a: Housing body; 101b: Housing cover; 108: Fixed friction part; 109: Fixed friction surface; 110: Input component; 110a: Fixing hole; 120: Intermediate component; 121: Intermediate body; 121a, 121b, 125a: Screw holes; 125: Rotating friction part; 125b: Rotating friction surface; 130: Output component; 131: Output body; 131a, 140a, 211a 212a, 221a, 222a: Through holes; 139: Output shaft; 140: Gasket; 180: Reducer; 181: Support shaft; 190: Motor; 191: Motor shaft; 202: Wheel; 210: First force-applying component; 211: First connecting part; 212: First fixing part; 220: Second force-applying component; 221: Second connecting part; 222: Second fixing part; 300: Cam mechanism; 310: First cam part; 311: Concave cam; 320: Second cam part; 321: Convex cam; 410: Output bearing; 420: Input bearing; 450: Bearing retaining component; 700: Bolt; 710: Nut.

Claims

1. A rotary transmission device comprising: The input component rotates about a central axis extending in a first direction by means of torque input from a drive source; An intermediate component is arranged coaxially with the input component on one side of the input component in the first direction. An output component is coaxially disposed on one side of the intermediate component in the first direction, along with the input component and the intermediate component. The first force-applying component connects the intermediate component and the output component, and applies force to the intermediate component toward the input component; A cam mechanism is disposed between the input component and the intermediate component, and transmits the rotation of the input component to the intermediate component; as well as The housing, which houses the aforementioned intermediate components and the aforementioned cam mechanism, holds the aforementioned input components and the aforementioned output components in a rotatable manner, and has a fixed friction surface. The aforementioned intermediate component has: The middle main body is positioned at the location through which the central axis passes, and is fixed with the first force-applying component. A rotating friction part is disposed at a position opposite to the fixed friction surface in the first direction; as well as The second force-applying component connects the intermediate main body and the rotating friction part, and applies force to the rotating friction part toward the fixed friction surface. The elastic modulus of the first force-applying component is greater than that of the second force-applying component. When the input component rotates, the cam mechanism maintains the state of transmitting the rotation of the input component to the intermediate main body and moves the intermediate main body toward the direction of the output component, while the rotating friction part moves away from the fixed friction surface via the second force-applying component.

2. The rotary transmission device according to claim 1, wherein, It also has: An angular contact ball bearing is disposed on the other side of the input component in the first direction between the input component and the housing, and supports the input component so that it can rotate relative to the housing but cannot move in the first direction.

3. The rotary transmission device according to claim 1 or 2, wherein, The first force-applying component is a plate-shaped elastic component that connects the intermediate main body and the output component in a second direction orthogonal to the first direction, and whose thickness direction is oriented towards the first direction.

4. The rotary transmission device according to claim 1 or 2, wherein, The second force-applying component is a plate-shaped elastic component that connects the intermediate main body and the rotating friction part in a second direction orthogonal to the first direction, and whose thickness direction is oriented towards the first direction.

5. The rotary transmission device according to claim 1 or 2, wherein, It also has: A gasket is disposed between the aforementioned intermediate main body and the aforementioned output component. The aforementioned intermediate main body portion is in a state of mutual pressing with the aforementioned output component in the aforementioned first direction via the aforementioned gasket, thereby restricting the movement of the direction in which it approaches the aforementioned output component.

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