Actuator and steering device of a reverse input cutoff clutch and control method of a reverse input cutoff clutch

Abstract

The present application prevents the phenomenon that the state in which the input member and the output member can rotate and the state in which the input member and the output member cannot rotate are alternately repeated in a short time. The reverse input cut clutch (4) has the following function: in a state in which a reverse input torque is input from an output side mechanism to an output member (8), a torque in a direction opposite to the direction of the reverse input torque from the output side mechanism to the output member (8) is imparted to an input member (7) by an actuator, thereby switching the reverse input cut clutch (4) to a state in which a torque can be transmitted between the input member (7) and the output member (8), and thereafter, a command to impart a torque having a magnitude smaller than that of the reverse input torque from the output side mechanism to the output member (8) in the above opposite direction to the input member (7) by the actuator, thereby transmitting the reverse input torque from the output side mechanism to the output member (8) to the input member (7).

Description

Technical Field

[0001] This disclosure relates to an actuator having a reverse input cut-off clutch that has the function of completely cutting off torque input in the opposite direction to the output component without transmitting it to the input component, a steering device having the actuator, and a control method for the aforementioned reverse input cut-off clutch. Background Technology

[0002] The reverse input cut-off clutch has an input component connected to the input side mechanism of a drive source, etc., and an output component connected to the output side mechanism of a reduction mechanism, etc. It has the following functions: it transmits the torque input to the input component to the output component, and in contrast, it locks the torque input to the output component in the opposite direction, that is, it completely cuts off the torque and does not transmit it to the input component.

[0003] Reverse input cut-off clutches are broadly classified into locking and free types based on the mechanism that cuts off the torque input in the reverse direction to the output component. Locking-type reverse input cut-off clutches have a mechanism that locks the rotation of the output component when torque is input in the reverse direction. On the other hand, free-type reverse input cut-off clutches have a mechanism that allows the output component to idle when torque is input in the reverse direction. The choice between locking and free-type reverse input cut-off clutches depends on the intended use of the assembly of the reverse input cut-off clutch.

[0004] International Publication No. 2021 / 107073 discloses a locking-type reverse input cut-off clutch. The reverse input cut-off clutch disclosed in International Publication No. 2021 / 107073 comprises: a pressed member having a pressed surface; an input member having an input-side engaging portion; an output member having an output-side engaging portion; and an engaging member having an input-side engaged portion, an output-side engaged portion, and a pressed surface.

[0005] If torque is input to the input component, the engaging member moves the pressing surface away from the pressing surface by engaging the input-side engaging portion with the input-side engaged portion, thereby engaging the output-side engaged portion with the output-side engaging portion and transmitting the torque input to the input component to the output component.

[0006] Conversely, if a reverse torque is input to the output component, the engaging member causes the pressing surface to move towards the pressed surface based on the engagement between the output-side engaging portion and the output-side engaged portion, and the pressing surface and the pressed surface engage friably. Thus, the rotation of the output component is locked.

[0007] In the reverse input cut-off clutch described in International Publication No. 2021 / 107073, regardless of the rotation direction of the input component, the torque input to the input component can be transmitted to the output component via the engagement member, and regardless of the rotation direction of the output component, the torque input to the output component in the opposite direction can be completely cut off and not transmitted to the input component.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: International Publication No. 2021 / 107073 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] In a lock-up reverse input cut-off clutch, when a torque in a predetermined direction is input to the output component in the opposite direction, if the torque input to the input component is in the same direction as the torque input to the output component in the opposite direction, i.e., in the predetermined direction, there is a possibility that the rotation of the input component and the output component will become unsmooth.

[0013] For example, in the reverse input cut-off clutch described in International Publication No. 2021 / 107073, if a torque in a predetermined direction is input to the output component in the reverse direction, the engaging member moves the pressing surface towards the pressed surface, causing frictional engagement between the pressing surface and the pressed surface. This locks the rotation of the output component. In this state, if a torque in a predetermined direction is input to the input component, the engaging member moves the pressing surface away from the pressed surface based on the engagement of the input-side engaging portion and the input-side engaged portion, and engages the output-side engaged portion with the output-side engaging portion. This allows torque transmission between the input and output components, and both the input and output components rotate in the predetermined direction.

[0014] At this time, if the rotation rate of the output component is greater than that of the input component, i.e., the rotation speed of the output component is faster than that of the input component, the engaging member immediately moves the pressing surface towards the pressed surface based on the engagement of the output-side engaging part and the output-side locked part, and causes the pressing surface to engage with the pressed surface through friction, thereby locking the rotation of the output component. Even in this state, because a torque in a predetermined direction is input to the input component, in the next instant, based on the engagement of the input-side engaging part and the input-side locked part, torque transmission is allowed between the input component and the output component, and the input component and the output component rotate in the predetermined direction.

[0015] As described above, when a torque in the reverse direction is input to the output component, if a torque in the same direction as the torque input to the output component is input to the input component, the input and output components will alternately switch between a locked-out state where they can rotate in the predetermined direction and a locked state where they cannot rotate for a short period of time. This can lead to a jittering phenomenon where the input and output components rotate intermittently in the predetermined direction. If this phenomenon occurs, the operation of the mechanical components connected to the output component may become sluggish.

[0016] The purpose of this disclosure is to realize an actuator with an attached reverse input cut-off clutch, a steering device, and a control method for the reverse input cut-off clutch: to prevent the phenomenon that the input and output components alternate between a rotatable state and a non-rotatable state for a short period of time when the lock is released.

[0017] Solution for solving the problem

[0018] One embodiment of this disclosure includes an actuator with an accompanying reverse input cut-off clutch, comprising an actuator and a reverse input cut-off clutch.

[0019] The aforementioned reverse input cut-off clutch has an input component that is driven by the rotation of the aforementioned actuator, and an output component that is connected to the output-side mechanism in a manner capable of transmitting torque. Furthermore, when no reverse torque is input from the output-side mechanism to the output component, if torque is input from the actuator to the input component, the torque input to the input component is transmitted to the output component. Conversely, when no torque is input from the actuator to the input component, if reverse torque is input from the output-side mechanism to the output component, the rotation of the output component is locked.

[0020] The aforementioned actuator drives the aforementioned input component to rotate.

[0021] In particular, in one embodiment of the present disclosure, the actuator of the accompanying reverse input cut-off clutch has the following function: when a torque is input in the reverse direction from the output-side mechanism to the output member, the actuator applies a torque to the input member in the opposite direction to the torque input in the reverse direction from the output-side mechanism to the output member, thereby switching the reverse input cut-off clutch to a state in which torque can be transmitted between the input member and the output member; thereafter, an instruction is continuously given to the actuator to apply a torque to the input member in the reverse direction that is smaller than the torque input in the reverse direction from the output-side mechanism to the output member, thereby transmitting the torque input in the reverse direction from the output-side mechanism to the output member to the input member.

[0022] In one embodiment of the present disclosure, the actuator with an accompanying reverse input cut-off clutch can be equipped with an electric motor.

[0023] In one embodiment of the present disclosure, the actuator with an accompanying reverse input cut-off clutch can include a pressed component, an input component, an output component, and an engaging component.

[0024] The aforementioned pressed component has a pressed surface on its inner circumferential surface.

[0025] The input component has an input-side engagement portion disposed radially inside the pressed surface and is supported so as to be able to rotate coaxially with the pressed surface.

[0026] The output component has an output-side engaging portion disposed radially inside the pressed surface compared to the input-side engaging portion, and is supported so as to be able to rotate coaxially with the pressed surface.

[0027] The aforementioned engaging member has a pressing surface facing the pressed surface, an input-side engaging portion capable of engaging with the input-side engaging portion, and an output-side engaging portion capable of engaging with the output-side engaging portion. The engaging member is configured to be movable in a first direction relative to the pressing surface in a near-far direction.

[0028] Furthermore, the aforementioned engaging member is configured such that if torque is input to the input component from the actuator, the pressing surface moves away from the pressed surface in the first direction based on the engagement between the input-side engaging portion and the input-side engaged portion, thereby transmitting torque between the input component and the output component. Conversely, if torque is input to the output component from the output-side mechanism in the opposite direction when no torque is input to the input component from the actuator, the pressing surface is pressed in the first direction towards the pressed surface based on the engagement between the output-side engaged portion and the output-side engaging portion, causing frictional engagement between the pressing surface and the pressed surface.

[0029] In one embodiment of the present disclosure, the actuator with an accompanying reverse input cut-off clutch is capable of having two pressing surfaces at two locations on the radially outer side where they are circumferentially separated.

[0030] In an actuator with an accompanying reverse input cut-off clutch according to one aspect of this disclosure, when the two pressing surfaces are pressed against the pressed surface as the output component rotates to one circumferential side, and the input-side engaging portion engages with the input-side engaged portion as the input component rotates to the other circumferential side, the distance between the contact portion of the input-side engaging portion and the input-side engaged portion in a second direction orthogonal to both the first direction and the rotation center of the input component and the rotation center of the input component is smaller than the distance between the contact portion of the output-side engaging portion and the output-side engaged portion in the second direction and the rotation center of the output component.

[0031] When the output component is input with reverse torque and the two pressing surfaces are in contact with the pressed surface, the contact portion of the output-side engaging portion and the output-side engaged portion is located on the side closer to the rotation center of the output component in the first direction compared to an imaginary straight line. This imaginary straight line connects one of the pressing surfaces and the abutting portion of the pressed surface to the rotation center of the output component.

[0032] In an actuator with an accompanying reverse input cut-off clutch according to one aspect of this disclosure, when the two pressing surfaces are pressed against the pressed surface as the output component rotates to one circumferential side, and the input-side engaging portion engages with the input-side engaged portion as the input component rotates to the other circumferential side, the distance between the contact portion of the input-side engaging portion and the input-side engaged portion in a second direction orthogonal to both the first direction and the rotation center of the input component and the rotation center of the input component is greater than the distance between the contact portion of the output-side engaging portion and the output-side engaged portion in the second direction and the rotation center of the output component.

[0033] When the output component is input with reverse torque and the two pressing surfaces are in contact with the pressed surface, the contact portion of the output-side engaging portion and the output-side engaged portion is located on the side closer to the rotation center of the output component in the first direction compared to an imaginary straight line. This imaginary straight line connects one of the pressing surfaces and the abutting portion of the pressed surface to the rotation center of the output component.

[0034] In one embodiment of the present disclosure, the actuator with an accompanying reverse input cut-off clutch is capable of having two engaging members, each composed of the aforementioned engaging members.

[0035] In one embodiment of the present disclosure, the actuator with an accompanying reverse input cut-off clutch can include an elastic member that elastically applies force to the engaging member in a direction that brings the pressing surface close to the pressed surface.

[0036] One steering device disclosed herein includes:

[0037] An actuator with an attached reverse input cut-off clutch, having an output component; and

[0038] A linear motion mechanism having a rod supported to perform linear motion and connected to the steering wheel in such a way that the orientation of the steering wheel changes according to the linear motion, and converting the rotational motion of the output component into the linear motion of the rod.

[0039] In particular, in a steering device according to one embodiment of the present disclosure, the aforementioned actuator with an attached reverse input cut-off clutch is constituted by an actuator with an attached reverse input cut-off clutch according to one embodiment of the present disclosure.

[0040] In one embodiment of the steering device disclosed herein,

[0041] The aforementioned rod has a helical external ball screw groove on its outer circumferential surface.

[0042] The aforementioned linear motion mechanism also has:

[0043] A ball nut having a helical inner ball screw groove on its inner circumferential surface, driven by the aforementioned output component for rotation; and

[0044] Multiple balls are arranged to roll freely between the inner ball screw groove and the outer ball screw groove.

[0045] In this case, the aforementioned linear motion mechanism is composed of a ball screw device.

[0046] In one embodiment of the steering device disclosed herein, the steering wheel is the rear wheel.

[0047] The reverse input cut-off clutch, which is the object of the control method of the reverse input cut-off clutch of this disclosure, has an input component that is driven by the aforementioned actuator for rotation and an output component that is connected to the output-side mechanism in a manner capable of transmitting torque. When no reverse torque is input from the aforementioned output-side mechanism to the aforementioned output component, if torque is input from the aforementioned actuator to the aforementioned input component, the torque input to the aforementioned input component is transmitted to the aforementioned output component. Conversely, when no torque is input from the aforementioned actuator to the aforementioned input component, if reverse torque is input from the aforementioned output-side mechanism to the aforementioned output component, the rotation of the aforementioned output component is locked.

[0048] In particular, in the control method of the reverse input cut-off clutch of one embodiment of this disclosure, when predetermined conditions are met, and in a state where torque is input in the reverse direction from the output-side mechanism to the output component, the actuator imparts a torque to the input component in the opposite direction to the torque input in the reverse direction from the output-side mechanism to the output component, thereby switching the reverse input cut-off clutch to a state in which torque can be transmitted between the input component and the output component. Then, an instruction is continuously given to the actuator to impart a torque to the input component in the opposite direction with a torque smaller than the torque input in the reverse direction from the output-side mechanism to the output component, thereby transmitting the torque input in the reverse direction from the output-side mechanism to the output component to the input component.

[0049] For example, the reverse input cut-off clutch, which is the object of the control method of the reverse input cut-off clutch of this disclosure, can include a pressed component, the aforementioned input component, the aforementioned output component, and an engaging component.

[0050] The aforementioned pressed component has a pressed surface on its inner circumferential surface.

[0051] The input component has an input-side engagement portion disposed radially inside the pressed surface and is supported so as to be able to rotate coaxially with the pressed surface.

[0052] The output component has an output-side engaging portion that is radially inner to the pressed surface compared to the input-side engaging portion, and is supported so as to be able to rotate coaxially with the pressed surface.

[0053] The aforementioned engaging member has a pressing surface facing the pressed surface, an input-side engaging portion capable of engaging with the input-side engaging portion, and an output-side engaging portion capable of engaging with the output-side engaging portion. The engaging member is configured to be able to move in a first direction relative to the pressing surface in a near-far direction.

[0054] Furthermore, the aforementioned engaging member is configured such that, if torque is input to the input component from the actuator, the pressing surface moves away from the pressed surface in the first direction based on the engagement between the input-side engaging portion and the input-side engaged portion, thereby enabling torque transmission between the input component and the output component. Conversely, if torque is input to the output component from the output-side mechanism in the opposite direction when no torque is input to the input component from the actuator, the pressing surface and the pressed surface engage friably in the first direction based on the engagement between the output-side engaged portion and the output-side engaging portion.

[0055] The effects of the invention

[0056] An actuator with an accompanying reverse input cut-off clutch according to one embodiment of the present disclosure can prevent the alternating and repeated shuddering phenomenon of the input and output components being in a rotatable state and a non-rotatable state for a short period of time when the lock is released. Attached Figure Description

[0057] Figure 1 This is a schematic diagram illustrating a steering device according to a first example of an embodiment of the present disclosure.

[0058] Figure 2 This is a cross-sectional view of the reverse input cut-off clutch of the steering device constituting the first example, viewed from the output component side.

[0059] Figure 3 yes Figure 2 X-X sectional view.

[0060] Figure 4 yes Figure 3 Y-Y sectional view.

[0061] Figure 5 This refers to the state in which the torque input to the input component is transmitted to the output component in relation to the reverse input disengagement clutch in the first example. Figure 4 Same diagram.

[0062] Figure 6 This indicates that the output component of the reverse input disengagement clutch in the first example is locked. Figure 4 Same diagram.

[0063] Figure 7 This refers to the state in which the torque input to the output component is transmitted to the input component in the reverse input disengagement clutch of the first example. Figure 4 Same diagram.

[0064] Figure 8 (A) Figure 8 (C) is a schematic diagram illustrating the effect of limiting the shape of the reverse input cut-off clutch in the first example.

[0065] Figure 9 This relates to a second example of an embodiment of the present disclosure, involving a reverse input cut-off clutch. Figure 4 Same diagram.

[0066] Figure 10 It concerns the reverse input disengagement clutch in the second example. Figure 5 Same diagram.

[0067] Figure 11 It concerns the reverse input disengagement clutch in the second example. Figure 6 Same diagram.

[0068] Figure 12 It concerns the reverse input disengagement clutch in the second example. Figure 7 Same diagram.

[0069] Figure 13 (A) and Figure 13 (B) is a diagram used to illustrate the effect of limiting the shape of the reverse input cut-off clutch in the second example. Detailed Implementation

[0070] [First example]

[0071] according to Figures 1 to 8 Section (C) describes a first example of an embodiment of this disclosure. This example applies an actuator with a reverse input cut-off clutch, a feature of this disclosure, to a steering device for rear wheels. The steering device 1 in this example includes an actuator 2 with a reverse input cut-off clutch and a linear motion mechanism 3 serving as an output-side mechanism. The steering device 1 in this example is a rear-wheel steering device. However, in implementing this disclosure, the steering device 1 of this example can also be applied to a front-wheel steering device. Furthermore, the actuator 2 with a reverse input cut-off clutch of this example can also be applied to various mechanical devices. Even in this case, the structure of the steering device or the actuator with a reverse input cut-off clutch is essentially the same as in this example.

[0072] In a vehicle equipped with the steering device 1 of this example, a sensor is used to detect the amount and speed of rotation of the steering wheel (not shown), vehicle speed, and / or the surrounding conditions, etc., as well as vehicle status. Based on the information from the sensor, an ECU (not shown) controls the amount of electricity supplied to the actuator 5 and the direction of electricity supply.

[0073] (with an actuator for reversing the input to cut off the clutch)

[0074] In this example, the actuator 2 with the attached reverse input cut-off clutch includes actuator 5 and reverse input cut-off clutch 4.

[0075] The actuator 5 rotates to drive the input component 7 of the reverse input disengagement clutch 4. In this example, the actuator 5 has an electric motor as the drive source.

[0076] Furthermore, in implementing this disclosure, an engine can also be used as the drive source for the actuator. Additionally, the actuator can also include a speed reducer between the drive source and the input component of the reverse input cut-off clutch.

[0077] The reverse input cut-off clutch 4 includes: an input component 7, which is rotaryly driven by an actuator 5; and an output component 8, which is connected to the ball nut 33 of the linear motion mechanism 3, which serves as the output-side mechanism, in a manner capable of transmitting torque. The input component 7 and the output component 8 are arranged coaxially with each other.

[0078] When the reverse input disengagement clutch 4 is not transmitting reverse torque from the linear motion mechanism 3 to the output component 8, if torque is transmitted from the actuator 5 to the input component 7, the torque transmitted to the input component 7 will be transferred to the output component 8 regardless of the rotation direction of the input component 7. More specifically, when the reverse input torque is not transmitting reverse torque from the linear motion mechanism 3 to the output component 8, if a torque greater than a predetermined torque is transmitted from the actuator 5 to the input component 7, the torque transmitted to the input component 7 will be transferred to the output component 8 regardless of the rotation direction of the input component 7. That is, the input component 7 and the output component 8 rotate as a single unit.

[0079] When no torque is input from actuator 5 to input component 7, if reverse torque is input from linear motion mechanism 3 to output component 8, the reverse input cut-off clutch 4 locks the rotation of output component 8 regardless of its rotation direction. Specifically, when no torque is input from actuator 5 to input component 7, if a torque greater than or equal to a predetermined locking torque is input from linear motion mechanism 3 to output component 8, the rotation of output component 8 is locked. That is, the torque input from linear motion mechanism 3 to output component 8 is completely cut off and not transmitted to input component 7.

[0080] Locking torque is the minimum torque required of the output component 8 to switch the reverse input cut-off clutch 4 to a locked state, i.e., the locked state of the output component 8, when the output component 8 rotates with the actuator 5 without any torque input to the input component 7. Specifically, in this example, locking torque is the minimum torque required of the output component 8 to cause the pressing surface 25 of the engaging member 10 to engage with the pressing surface 11 of the pressed member 9 through friction, regardless of the direction of rotation of the output component 8, when the output component 8 rotates with the actuator 5 without any torque input to the input component 7.

[0081] In this example, the reverse input cut-off clutch 4 includes a pressed part 9, an input part 7, an output part 8, and an engaging part 10. The reverse input cut-off clutch 4 in this example has two engaging parts 10.

[0082] The pressed component 9 has a cylindrical shape and is fixed to, for example, a housing or other component not shown, or integrally disposed with other components, thereby restricting its rotation. The pressed component 9 has a pressed surface 11 on its inner circumferential surface, which is a concave surface in the shape of a cylindrical surface.

[0083] The input component 7 has an input-side engaging portion 12 disposed radially inside the pressed surface 11, and is supported so as to be able to rotate coaxially with the pressed surface 11. The input component 7 is driven to rotate by the actuator 5.

[0084] In this example, the input component 7 includes a base plate portion 13, an input shaft portion 14, and an input side engaging portion 12.

[0085] The substrate portion 13 has an end face shape that is approximately circular when viewed from the axial direction.

[0086] The input shaft portion 14 extends from one axial side of the base plate portion 13. Figure 3 The central portion of the right side of the input shaft 14 protrudes towards the axial side. The input shaft portion 14 has an input handle portion 15 on the axial side. In this example, the input handle portion 15 has a shape with opposite sides of a pair of parallel flat surfaces on its outer circumferential surface. However, the input handle portion 15 can be configured in any shape if it is connected to the actuator 5 in a manner capable of transmitting torque. Alternatively, the input shaft portion and the output shaft of the electric motor, which serves as the actuator, can be integrally formed.

[0087] The input component 7 has the same number of input-side engaging portions 12 as the engaging component 10. That is, in this example, the input component 7 has two input-side engaging portions 12.

[0088] The input-side engaging portion 12 has an end face shape that is generally fan-shaped or generally trapezoidal when viewed from the axial direction, and is located on the other side of the base plate portion 13 from the axial direction. Figure 3 The two input-side engaging portions 12 protrude radially outward from the opposite side of the left side of the input component 7. They are radially separated from each other. Therefore, each input-side engaging portion 12 is located on the opposite side of the base plate portion 13, offset radially outward from the rotation center O. Furthermore, each input-side engaging portion 12 has a circumferentially symmetrical shape.

[0089] In this example, the radially inner surface 16 of each input-side engaging portion 12 is composed of mutually parallel flat surfaces, and the radially outer surface 17 of each input-side engaging portion 12 has a cylindrical profile shape similar to the outer peripheral surface of the base plate portion 13. In addition, the pair of circumferential side surfaces 18 of each input-side engaging portion 12 are composed of flat surfaces that are inclined towards the direction of separation from each other as they move radially outward.

[0090] The output component 8 has an output-side engaging portion 19 disposed radially inward of the pressed surface 11 compared to the input-side engaging portion 12, and is supported so as to be able to rotate coaxially with the pressed surface 11. In this example, the output component 8 has an output shaft portion 20 and an output-side engaging portion 19.

[0091] The output shaft portion 20 has a flange portion 21 protruding radially outward at one end on the axial side, and an output handle portion 22 on the other axial side. In this example, the output handle portion 22 has a shape with opposite side distances including a pair of parallel flat surfaces on its outer circumferential surface. A drive gear 38, serving as the torque output portion of the actuator 2 with an attached reverse input cut-off clutch, is externally fitted into the output handle portion 22 in a manner capable of transmitting torque. However, the output handle portion 22 can be configured in any shape if it can be connected to the torque output portion of the actuator 2 with the attached reverse input cut-off clutch, i.e., the drive gear 38, in a manner capable of transmitting torque.

[0092] The output-side engagement portion 19 has a cam function. That is, the distance from the rotation center O of the output component 8 to the outer peripheral surface of the output-side engagement portion 19 is not constant in the circumferential direction. In this example, the output-side engagement portion 19 has an end face shape that is approximately rectangular or approximately elongated elliptical when viewed from the axial direction, and protrudes from the center of the end face on the axial side of the output shaft portion 20 toward the axial side. That is, the outer peripheral surface of the output-side engagement portion 19 is composed of a pair of parallel flat surfaces 23 and a pair of convex curved surfaces 24, each of which is partially cylindrical. Therefore, the distance from the rotation center O of the output component 8 to the outer peripheral surface of the output-side engagement portion 19 is not constant throughout the circumferential direction. Furthermore, in this example, the pair of convex curved surfaces 24 are composed of partially cylindrical surfaces centered on the rotation center O of the output component 8.

[0093] The output-side engaging portion 19 is symmetrical with respect to an imaginary plane passing through the rotation center O of the output component 8 and orthogonal to a pair of flat surfaces 23, and is also symmetrical with respect to an imaginary plane passing through the rotation center O of the output component 8 and parallel to a pair of flat surfaces 23. The output-side engaging portion 19 is disposed radially inside each input-side engaging portion 12. That is, in this example, the output-side engaging portion 19 is disposed between the two input-side engaging portions 12.

[0094] Each engaging member 10 includes: a pressing surface 25 opposite to the pressing surface 11; an input-side engaging portion 26 that can engage with the input-side engaging portion 12; and an output-side engaging portion 27 that can engage with the output-side engaging portion 19.

[0095] Regarding the radial direction of the snap-fit ​​component 10, Figure 4 The direction indicated by arrow A, which is perpendicular to the flat surface 29 provided with the radial inner side, refers to the width direction of the engaging member 10. Figure 4 The direction indicated by arrow B is parallel to the flat surface 29. In this example, the radial direction with respect to the engaging member 10 is the near-far direction of the pair of pressing surfaces 25 of the engaging member 10 relative to the pressed surface 11, which corresponds to the first direction. The width direction with respect to the engaging member 10 corresponds to the second direction, which is orthogonal to both the first direction and the rotation center O of the input member 7.

[0096] In this example, each engaging member 10 has an end face shape that is approximately semi-circular when viewed from the axial direction, and also has a shape that is symmetrical in the width direction.

[0097] The pressing surfaces 25 are provided on the radially outer surfaces of the engaging member 10 opposite to the pressed surfaces 11. In this example, the pressing surfaces 25 are respectively provided at two circumferentially separated locations on the radially outer surfaces of the engaging member 10. Each pressing surface 25 is composed of a partially cylindrical convex surface having a radius of curvature smaller than that of the pressed surfaces 11. Furthermore, when viewed from the axial direction, the portion of the radially outer surfaces of the engaging member 10 that is circumferentially offset from the two pressing surfaces 25 exists centered on the central axis O of the input member 7 and is located radially inward compared to the imaginary circle that contacts the two pressing surfaces 25. That is, when the two pressing surfaces 25 are in contact with the pressed surfaces 11, the portion of the radially outer surfaces of the engaging member 10 that is circumferentially offset from the two pressing surfaces 25 does not contact the pressed surfaces 11.

[0098] Each pressing surface 25 preferably has a surface property that has a larger coefficient of friction relative to the pressed surface 11 than other parts of the engaging member 10. In addition, each pressing surface 25 can be integrally formed with other parts of the engaging member 10, or it can be formed on the surface of a friction material that is fixed by adhesive or bonding in other parts of the engaging member 10.

[0099] The input-side engaging portion 26 is provided in the radially intermediate portion of the central portion in the width direction of the engaging member 10. The input-side engaging portion 26 has an opening shape that is generally arc-shaped when viewed axially, and is formed by a through hole that axially penetrates the radially intermediate portion at the central position in the width direction of the engaging member 10. The input-side engaging portion 26 is sized to allow for loose insertion of the input-side engaging portion 12. Therefore, when the input-side engaging portion 12 is inserted into the inner side of the input-side engaging portion 26, gaps exist between the inner surfaces of the input-side engaging portion 12 and the input-side engaging portion 26, and in both the width direction and radial direction of the engaging member 10. Therefore, the input-side engaging portion 12 can be displaced relative to the engaging member 10 in a direction related to the rotation of the input component 7, and the engaging member 10 can be displaced radially relative to the input-side engaging portion 12. In this example, the input-side engaging portion 26 has a flat surface 28 on its radially inner side facing radially outward, which is parallel to the flat surface 29 provided on the radially inner side of the engaging member 10.

[0100] Furthermore, in implementing this disclosure, the input-side engaging portion can also be formed by a bottomed hole that opens only on one axial side of the engaging member. Alternatively, the input-side engaging portion can also be formed by a cut that opens on the radially outer side of the engaging member.

[0101] The output-side engaging portion 27 is provided at the center of the radially inner surface of the engaging member 10 in the width direction. In this example, the engaging member 10 has a flat surface 29 on the radially inner surface, and two protrusions 30 protruding radially inward at two locations in the width direction of the flat surface 29. The output-side engaging portion 27 is formed by the portion of the flat surface 29 that exists between the two protrusions 30 in the width direction. The width dimension of the output-side engaging portion 27, that is, the distance between the two protrusions 30, is larger than the width dimension of the flat surface 23 of the output-side engaging portion 19.

[0102] In the reverse input cut-off clutch 4 of this example, with the two pressing surfaces 25 of each engaging member 10 facing opposite sides radially and the radially inner surfaces (flat surfaces 29) of each engaging member 10 facing each other, the two engaging members 10 are arranged radially (in the first direction) inside the pressed member 9 so as to allow radial (first direction) movement of each engaging member 10. Furthermore, the two input-side engaging portions 12 of the input member 7, located on one axial side, are axially inserted into the input-side engaging portions 26 of each engaging member 10, and the output-side engaging portions 19 of the output member 8, located on the other axial side, are axially inserted between the output-side engaging portions 27 of the two engaging members 10. That is, the two engaging members 10 are configured such that the output-side engaging portions 19 are clamped radially outward by the output-side engaging portions 27 of the two engaging members 10.

[0103] Furthermore, with the two engaging members 10 positioned radially inside the pressed member 9, the inner diameter of the pressed member 9 and the radial dimension of the engaging members 10 are limited such that there is a gap between the pressed surface 11 and each pressed surface 25, and between the front end faces of the protrusions 30 and each other.

[0104] In the case of an actuator with an accompanying reverse input cut-off clutch implementing one aspect of the present disclosure, the reverse input cut-off clutch can also include a component that elastically applies force to the engaging members in the direction that brings the pressing surface closer to the pressed surface. In the reverse input cut-off clutch 4 of this example, for example, the force-applying component can be composed of two compression coil springs that prevent disengagement by inserting each protrusion 30 into the inner side of the ends on both sides of the longitudinal direction between each of the two combinations of the protrusions 30 of the two engaging members 10. Alternatively, the force-applying component can be composed of two leaf springs disposed between the flat surface 29 of the two engaging members 10 and the output side engaging portion 19.

[0105] In the reverse input cut-off clutch 4 of this example, when no reverse torque is input from the linear motion mechanism 3 (which is the output-side mechanism) to the output component 8, if torque is input from the actuator 5 to the input component 7, then as follows: Figure 5As shown, inside the input-side engaging portion 26, the input-side engaging portion 12 is in the rotational direction of the input component 7 (in... Figure 5 In the example, the rotation is counterclockwise. Therefore, the radially inner surface 16 of the input-side engaging portion 12 presses against the flat surface 28 of the input-side engaging portion 26 radially inward, applying a force to the two engaging members 10 in a first direction that causes the pressing surface 25 to move away from the pressed surface 11. As a result, the engaging members 10 move the pressing surfaces 25 in the first direction away from the pressed surface 11. That is, the two engaging members 10, based on their engagement with the input member 7, move towards each other in a direction that approaches each other radially inward (so that the surfaces located at...). Figure 5 The upper engaging member 10 faces downward, so that it is located on the lower side. Figure 5 The lower locking piece 10 moves towards the upper side.

[0106] As a result, the radially inner surfaces of the two engaging members 10 move toward each other, and the output sides of the two engaging members 10 are held in place by the engaging portions 27 from both radial sides by the output side engaging portions 19 of the output component 8. That is, the output component 8 is rotated such that the flat surface 23 of the output side engaging portion 19 is parallel to the flat surface 29 of the engaging member 10, and the output side engaging portion 19 is engaged with the output sides of the two engaging members 10 by the engaging portions 27 without wobbling. As a result, the locking of the output component 8 is released, and torque can be transmitted between the input component 7 and the output component 8. In other words, the input component 7 and the output component 8 rotate as a unit. In summary, the torque input to the input component 7 is transmitted to the output component 8 via the two engaging members 10.

[0107] Conversely, if torque is input in the reverse direction from the linear motion mechanism 3 to the output component 8 when no torque is input from the actuator 5 to the input component 7, then as follows: Figure 6 As shown, the output-side engaging portion 19 is located on the output side of the two engaging members 10, and the engaging portion 27 is inside each other in the rotational direction of the output member 8 (in the direction of rotation). Figure 6 In the example, the rotation is clockwise. Therefore, the corner of the outer peripheral surface of the output-side engaging portion 19, which serves as the connection between the flat surface 23 and the convex curved surface 24, presses the output-side engaging portion 27 radially outward, and presses the two engaging members 10 towards the direction approaching the pressed surface 11. That is, based on their engagement with the output component 8, the two engaging members 10 move towards the direction of separation, i.e., radially outward (towards the direction where they are located). Figure 6 The upper engaging part 10 faces upwards, and will be located on the side of Figure 6 The lower engaging member 10 is pressed (facing downwards). As a result, the pressing surfaces 25 of the two engaging members 10 are pressed against the pressed surface 11 and engaged by friction.

[0108] As a result, the torque input to the output component 8 is completely cut off and is not transmitted to the input component 7. That is, the two engaging members 10 are clamped between the output-side engaging portion 19 and the pressed component 9 in such a way that the two pressing surfaces 25 do not slide relative to the pressed surface 11, thereby locking the output component 8.

[0109] In the reverse input cut-off clutch 4 of this example, the clearance between each component is adjusted in a manner that allows the above-mentioned actions to be performed. Furthermore, in Figure 5 as well as Figure 6 The radial gap between the input component 7 and the output component 8 and the two engaging parts 10 is exaggeratedly shown in the image.

[0110] In this example, the reverse input cut-off clutch 4 has two engaging elements 10. However, in the implementation of this disclosure, if the above actions can be achieved, the reverse input cut-off clutch can have only one engaging element, or it can have three or more engaging elements.

[0111] Especially in the reverse input cut-off clutch 4 of this example, in the positional relationship between the two pressing surfaces 25 of each engaging member 10 and the pressed surface 11, there is a gap between the radially inner surface 16 of the input-side engaging portion 12 and the inner surface of the input-side pressed portion 26, allowing the two pressing surfaces 25 to be further pushed toward the pressed surface 11 based on the corner of the output-side engaging portion 19 pressing the output-side pressed portion 27. Therefore, when each engaging member 10 moves radially outward based on the reverse input torque to the output member 8, the movement of each engaging member 10 is prevented from being blocked by the input-side engaging portion 12. Moreover, after the two pressing surfaces 25 contact the pressed surface 11, the surface pressure acting on the contact portion between the two pressing surfaces 25 and the pressed surface 11 also varies according to the magnitude of the reverse input rotational torque to the output member 8, thereby appropriately locking the output member 8.

[0112] Furthermore, in the reverse input cut-off clutch 4 of this example, the size and shape of each part constituting the pressed part 9, the input part 7, the output part 8, and the two engaging parts 10 are restricted in a manner that satisfies the following relationship.

[0113] First, the accompanying output component 8 is directed in a predetermined direction (e.g.) Figure 4 The two pressing surfaces 25 are pressed against the pressed surface 11 by the clockwise rotation of the input component 7, and the input component 7 moves in the opposite direction to the predetermined direction (e.g., clockwise). Figure 4 The input-side engaging portion 12 is engaged with the input-side engaged portion 26 when the input-side engaging portion 12 rotates counterclockwise (in a counterclockwise direction), that is, a portion of the input-side engaging portion 12 is in contact with the input-side engaged portion 26, so that the contact portion P of the input-side engaging portion 12 and the input-side engaged portion 26 is engaged. inThe distance D1 between the rotation center O of the input component 7 and the first distance D1 in the second direction is greater than the contact portion P of the output-side engaging part 19 and the output-side engaged part 27. out The second distance D2 between the rotation center O of the output component 8 and the second distance D2 in the second direction is smaller (D1 < D2).

[0114] In addition, such as Figure 6 As shown, in the locked state where the torque is input in the opposite direction to the output component 8 and the two pressing surfaces 25 of each engaging member 10 are in contact with the pressed surface 11, the contact portion C1 of the output-side engaging portion 19 and the output-side engaged portion 27 is located on the side closer to the rotation center O of the output component 8 in the first direction compared to the imaginary straight line L. Figure 6 (the lower side), the imaginary straight line L is the straight line that connects one of the two pressing surfaces 25, specifically the pressing surface 25 on the side closer to the contact part C1 than the rotation center O of the output component 8 in the second direction, and the abutting part C2 of the pressed surface 11 to the rotation center O of the output component 8.

[0115] (Control method for reversing the clutch input)

[0116] The actuator 2 with an attached reverse input cut-off clutch in this example is characterized in that the reverse input cut-off clutch 4 is controlled in the following manner. In this example, when the actuator 2 with the attached reverse input cut-off clutch is in a state where a reverse torque is input from the linear motion mechanism 3 (which is the output-side mechanism) to the output component 8, the actuator 5 imparts to the input component 7 the direction of the reverse torque input from the linear motion mechanism 3 to the output component 8 (e.g., ...). Figure 7 (clockwise direction) opposite direction (e.g.) Figure 7 The torque is applied in the counterclockwise direction. This switches the reverse input cut-off clutch 4 to a state where it can transmit torque between the input component 7 and the output component 8. Specifically, the actuator 5 applies a torque to the input component 7 in the direction opposite to the direction of the torque input to the output component 8, having a predetermined lock-out torque or greater, thereby switching the reverse input cut-off clutch 4 to a state where it can transmit torque between the input component 7 and the output component 8. Preferably, in this example, the actuator 5 applies a torque to the input component 7 in the direction opposite to the direction of the torque input to the output component 8, having a predetermined lock-out torque or greater but less than the magnitude of the torque input to the output component 8.

[0117] Furthermore, the magnitude of the lock-out torque is the minimum torque required from the input component 7 to switch the reverse input cut-off clutch 4 to the lock-out state in order to rotate with the input component 7, i.e., to separate the pressing surface 25 of the engaging component 10 from the pressed surface 11. In the reverse input cut-off clutch 4 of this example, for instance, when the rear wheel 31, which is the steering wheel, wants to return to a straight-line state from a state with a rudder angle based on the restoring force generated by the automatic alignment torque, the magnitude of the aforementioned lock-out torque is smaller than the magnitude of the torque input to the output component 8 in reverse based on the aforementioned automatic alignment torque when the reverse torque is input from the linear motion mechanism 3 to the output component 8.

[0118] That is, if the actuator 5 rotates to drive the input component 7 in a direction opposite to the direction of the torque input from the linear motion mechanism 3 to the output component 8, the radially inner surface 16 of the input-side engaging portion 12 presses against the flat surface 28 of the input-side engaging portion 26 towards the radially inner side, and the two engaging members 10 move away from the pressed surface 11. As a result, the output-side engaging portions 27 of the two engaging members 10 hold the output-side engaging portions 19 of the output component 8 from both radial sides, and the output-side engaging portions 19 engage with the output-side engaging portions 27 of the two engaging members 10, thus enabling the transmission of torque between the input component 7 and the output component 8.

[0119] After switching the reverse input cut-off clutch 4 to a state capable of transmitting torque between the input component 7 and the output component 8, the actuator 2 with the reverse input cut-off clutch continuously provides the following instruction: the actuator 5 applies a torque to the input component 7 in the opposite direction to the torque input to the output component 8, with a torque smaller than the torque input from the linear motion mechanism 3 to the output component 8. Thus, the torque input from the linear motion mechanism 3 to the output component 8 is transmitted to the input component 7.

[0120] That is, when the pressing surfaces 25 of the two engaging members 10 are separated from the pressed surfaces 11, if a torque greater than that input to the output member 8 is input to the input member 7, the input member 7 will rotate in such a way that it is pushed back by the output member 8 via the two engaging members 10. Thus, the torque input from the linear motion mechanism 3 to the output member 8 is transmitted to the input member 7.

[0121] Furthermore, after switching the reverse input cut-off clutch 4 to a state capable of transmitting torque between the input component 7 and the output component 8, the command value of the torque supplied to the input component 7 by the actuator 5 is only sufficient to prevent the reverse input cut-off clutch 4 from switching to a locked state. Specifically, the magnitude of the torque supplied to the input component 7 by the actuator 5 is sufficient to suppress the engagement member 10 from moving in the direction that brings the pressing surface 25 closer to the pressed surface 11 due to the action of the force-applying member. Therefore, once the reverse input cut-off clutch 4 switches to a locked-out state capable of transmitting torque between the input component 7 and the output component 8, the command value of the torque supplied to the input component 7 by the actuator 5 can be made extremely small compared to the aforementioned locked-out torque.

[0122] The torque transmitted to the input component 7 is absorbed by the electric motor that constitutes the actuator 5, which becomes a load.

[0123] (Steering mechanism)

[0124] In the steering device 1 of this example, the following conditions are set: when the rear wheel 31, which is the steering wheel, wants to return from the state with the rudder angle to the straight-line state based on the restoring force generated by the automatic alignment torque, the torque input from the linear motion mechanism 3 to the output component 8 can be transmitted to the input component 7. Conversely, when the rear wheel 31 jumps onto the curb or the like and an impact torque is applied from the linear motion mechanism 3 to the output component 8, the output component 8 is locked.

[0125] Specifically, when the magnitude of the torque input from the linear motion mechanism 3 to the output component 8 and the rate of increase are within a predetermined range, the actuator 5 is energized, imparting a torque of at least the magnitude of a predetermined locking release torque to the input component 7 in the opposite direction to the torque input to the output component 8, thereby enabling the torque input from the linear motion mechanism 3 to the output component 8 to be transmitted to the input component 7. Then, the following instruction is continuously given: the actuator 5 imparts a torque to the input component 7 in the opposite direction to the torque input to the output component 8, with a magnitude smaller than the magnitude of the torque input from the linear motion mechanism 3 to the output component 8. Thus, the torque input to the output component 8 is transmitted to the input component 7.

[0126] On the other hand, if the magnitude of the torque input from the linear motion mechanism 3 to the output component 8 is too large and / or the speed of increase is too high, the power supply to the actuator 5 is stopped, the input component 7 is not given torque, and the output component 8 is locked.

[0127] The magnitude and rate of change of the torque input in reverse from the linear motion mechanism 3 to the output component 8 can be estimated based on the current value of the electric motor constituting the actuator 5. Alternatively, the magnitude and rate of change of the torque input in reverse to the output component 8 can be determined based on the output signal of the torque sensor installed on the output component 8. Alternatively, the magnitude and rate of change of the torque input in reverse to the output component 8 can be determined by calculating the load applied to the rear wheel 31 based on the output signals of the yaw rate sensor, acceleration sensor, etc., installed on the vehicle body.

[0128] Furthermore, when the torque input from the linear motion mechanism 3 to the output component 8 can be transmitted to the input component 7, if the actuator 5 applies a torque to the input component 7 in a direction opposite to the torque input from the linear motion mechanism 3 to the output component 8, and this torque is larger than the magnitude of the torque input from the linear motion mechanism 3 to the output component 8, then the torque input to the input component 7 can be transmitted to the output component 8. In the actuator 2 with the included reverse input cut-off clutch in this example, the torque input from the linear motion mechanism 3 to the output component 8 is transmitted to the input component 7. From this state onwards, increasing the torque input to the input component 7 can reverse the transmission direction of the torque within the reverse input cut-off clutch 4. Even in this case, the engaging member 10 will not move radially, and the pressing surface 25 will not contact the pressed surface 11. That is, the change of the transmission direction of the torque within the reverse input cut-off clutch 4 can be performed smoothly.

[0129] The linear motion mechanism 3 in this example has a lever 32 that converts the rotational motion of the output component 8 into axial motion of the lever 32. The lever 32 is supported in a manner that allows it to perform linear motion along its own axis, and is connected to the rear wheel 31 in such a way that the orientation of the rear wheel 31, which serves as a steering wheel, changes according to this axial motion. The linear motion mechanism 3 in this example also includes a ball nut 33 and a plurality of balls 34. That is, the linear motion mechanism 3 in this example is constructed from a ball-type feed screw mechanism.

[0130] The rod 32 has a helical outer ball screw groove on its outer peripheral surface. The rod 32 is supported in a manner that allows for axial linear movement in the width direction of the vehicle body but does not allow for rotation.

[0131] The lever 32 is connected to the rear wheel 31 in such a way that the orientation of the rear wheel 31 changes according to its own axial linear movement. Specifically, the base ends of tie rods 35 are connected to the ends of the lever 32 on both sides of its axial direction via ball joints (not shown). The base ends of steering knuckle arms 36 are pivotally supported at the front ends of each tie rod 35. Steering knuckles are pivotally supported at the front ends of each steering knuckle arm 36 around a center pin. Each rear wheel 31 is rotatably supported on the steering knuckles via hub unit bearings.

[0132] The ball nut 33 has a helical inner ball screw groove on its inner circumferential surface, which allows it to be rotatably supported around the rod 32. The ball nut 33 is rotated by the output part 8 of the actuator 2, which is equipped with a reverse input cut-off clutch.

[0133] In this example, the ball nut 33 is driven to rotate by the output component 8 via the torque transmission mechanism 37. That is, the steering device 1 in this example has a torque transmission mechanism 37, which transmits the rotational motion of the output component 8 of the actuator 2 with a reverse input disengagement clutch to the torque input part of the linear motion mechanism 3, namely the ball nut 33.

[0134] The torque transmission mechanism 37 includes: a drive gear 38 externally fixed to the output shank 22 of the output component 8; an intermediate gear 39 meshing with the drive gear 38; and a driven gear 40 disposed around the ball nut 33 and meshing with the intermediate gear 39. That is, in this example, the torque transmission mechanism 37 is constituted by a gear-type reducer.

[0135] Furthermore, in implementing this disclosure, the drive gear of the output component of the actuator equipped with the reverse input cut-off clutch can directly mesh with the driven gear of the torque input part of the linear motion mechanism, i.e., the ball nut, or it can have two or more intermediate gears. Alternatively, the torque transmission mechanism for transmitting the rotational motion of the output component to the ball nut can be constructed using either a belt or chain reducer or a worm gear reducer.

[0136] Multiple balls 34 are arranged to roll freely on the load path formed by the outer ball screw groove of the rod 32 and the inner ball screw groove of the ball nut 33.

[0137] Furthermore, the start and end points of the load path are provided on the inner circumferential surface of the ball nut 33 or connected by a circulation path provided on a circulation component fixed to the ball nut 33.

[0138] According to the steering device 1 in this example, when a steering angle is applied to the two rear wheels 31, sensors detect the amount and speed of rotation of the steering wheel (not shown), the vehicle speed, and / or the surrounding conditions. Based on the information from these sensors, an ECU (not shown) controls the amount and direction of power supplied to the actuator 5. Therefore, if the input component 7 is rotated, as shown... Figure 5 As shown, the lock of the reverse input cut-off clutch 4 is released, and the rotation of the input component 7 is transmitted to the output component 8.

[0139] The rotation of the output component 8 is transmitted to the ball nut 33 by the torque transmission mechanism 37. As the ball nut 33 rotates, the rod 32 moves axially, thereby pushing and pulling the lever 35 to impart a rudder angle to the rear wheel 31.

[0140] When the rear wheel 31 returns from a state with a rudder angle to a straight-line state, in order to transmit the torque input in the opposite direction from the linear motion mechanism 3 to the output component 8 via the torque transmission mechanism 37 to the input component 7 based on the restoring force generated by the automatic alignment torque, the actuator 5 applies a torque to the input component 7 in the opposite direction to the torque input to the output component 8. Specifically, the actuator 5 instructs the input component 7 to apply a torque of a magnitude greater than or equal to the predetermined locking release torque in the opposite direction to the torque input to the output component 8. Then, the following instruction is continuously given: the actuator 5 applies a torque to the input component 7 in the opposite direction to the torque input to the output component 8, with a magnitude smaller than the torque input to the output component 8. Thus, as Figure 7 As shown, the reverse input disengagement clutch 4 is configured to transmit the torque input in reverse from the linear motion mechanism 3 to the output component 8 via the torque transmission mechanism 37 to the input component 7 based on the restoring force generated by the automatic alignment torque. This allows the output component 8 to rotate, thereby allowing the axial movement of the lever 32. As a result, the rear wheel 31 can return to the straight-line state based on the restoring force generated by the automatic alignment torque.

[0141] Furthermore, if, during the process of the rear wheel 31 returning to a straight-line state from the state where a predetermined rudder angle has been applied to the rear wheel 31, based on the restoring force generated by the automatic alignment torque, the magnitude of the torque applied to the input component 7 is greater than the torque applied to the output component 8 in the opposite direction, then a predetermined rudder angle can be applied to the rear wheel 31 again.

[0142] On the other hand, when an impact load such as the rear wheel 31 jumping onto a curb applies an impact torque to the output component 8 via the torque transmission mechanism 37 from the linear motion mechanism 3, in order to cut off the torque input to the output component 8 in the opposite direction and prevent it from being transmitted to the input component 7, the power supply to the actuator 5 is stopped, and no torque is applied to the input component 7. Thus, as... Figure 6 As shown, the axial movement of the lever 32 is prevented by locking the output component 8. As a result, even when an impact load is applied to the rear wheel 31, no steering angle is applied to the rear wheel 31, thus preventing the vehicle's movement from becoming unstable.

[0143] In the steering device 1 of this example, a linear motion mechanism 3 is constituted by a ball screw mechanism, which converts the rotational motion of the electric motor constituting the actuator 5 into the linear motion of the rod 32. The ball screw mechanism offers superior performance compared to a sliding thread mechanism that allows the internal thread groove on the inner circumferential surface of the nut to slide into contact with the external thread groove on the outer circumferential surface of the rod. Therefore, according to the steering device 1 of this example, the electric motor constituting the actuator 5 can be miniaturized.

[0144] Furthermore, the steering device 1 in this example includes an actuator 2 with an attached reverse input cut-off clutch that cuts off the torque input to the output component 8 without transmitting torque to the input component 7. Therefore, even when using a ball screw mechanism as the linear motion mechanism 3, it is possible to prevent the rear wheel 31 from being inadvertently given a steering angle due to applying an impact load to the rear wheel 31.

[0145] On the other hand, in the actuator 2 with the reverse input cut-off clutch in this example, when it is desired to transmit the torque input from the linear motion mechanism 3 to the output component 8 via the torque transmission mechanism 37 to the input component 7, the actuator 5 applies a torque to the input component 7 in the opposite direction to the torque input from the linear motion mechanism 3 to the output component 8. This applies a force to the engaging member 10 in the direction that separates each pressing surface 25 from the pressed surface 11, i.e., radially inward, causing the engaging member 10 to move radially inward. Furthermore, by separating each pressing surface 25 from the pressed surface 11, the torque input to the output component 8 in the opposite direction can be transmitted to the input component 7. Then, the following instruction is continuously given: the actuator 5 applies a torque to the input component 7 in the opposite direction to the torque input to the output component 8, having a magnitude smaller than the torque input from the linear motion mechanism 3 to the output component 8, thereby transmitting the torque input from the linear motion mechanism 3 to the output component 8 to the input component 7.

[0146] Therefore, it can prevent the following jerking phenomenon and prevent the input and output components from rotating unevenly: when a torque in the reverse direction is input to the output component, such as when a torque in the same direction as the torque input to the input component is input to the output component in order to release the lock of the reverse input disengagement clutch, the input and output components alternately and repeatedly switch between a state in which they can rotate in the predetermined direction and a state in which they cannot rotate for a short period of time, and the input and output components rotate intermittently in the predetermined direction.

[0147] Specifically, in the steering device 1 of this example, the rear wheel 31 can be smoothly returned from the state of being given a rudder angle to the straight-line state, which can prevent passengers, including the driver, from feeling uncoordinated.

[0148] Furthermore, even when the restoring force generated by the automatic alignment torque is used to input the torque in the opposite direction to the output unit 8 to accompany the rear wheel 31 back to a straight state, it is possible to impart a torque in the same direction as the torque input in the opposite direction to the output unit 8 based on instructions from the ECU.

[0149] In the reverse input cut-off clutch 4 of this example, the first distance D1 is made smaller than the second distance D2, and in the locked state, the contact portion C1 is located on the side closer to the rotation center O of the output component 8 in the first direction than the imaginary straight line L. Therefore, a smooth switch from the locked state to the unlocked state can be performed. (Refer to...) Figure 8 (A) Figure 8 (C) provides an explanation for this reason.

[0150] When the reverse input cut-off clutch 4 is locked, if torque is input to the input component 7, each engaging component 10 tends to rotate around the contact portion C1.

[0151] When the first distance D1 is larger than the second distance D2 (D1 > D2), such as Figure 8 As shown in (B), if a counterclockwise torque is input to the input component 7, the engaging member 10 tends to rotate counterclockwise around the contact portion C1. Furthermore, as... Figure 8 In (B), the trajectory r is represented by a single-dot dashed line, and one of the two pressing surfaces 25 is located on the opposite side of the contact portion C1 in the second direction, separated from the rotation center O of the output component 8. Figure 8 The pressing surface 25 (right side of (B)) tends to be forcefully pressed against the pressed surface 11 and thus engaged. In order to release the engagement of the pressing surface 25 with the pressed surface 11, when switching from the locked state to the unlocked state, the torque of the input component 7 increases instantaneously, i.e., a peak torque is generated.

[0152] Furthermore, if the contact portion C1 is located on a side further away from the rotation center O of the output component 8 in the first direction than the imaginary straight line L, such as Figure 8 As shown in (C), if a counterclockwise rotational torque is input to the input component 7, the engaging member 10 tends to rotate clockwise around the contact portion C1. Furthermore, as... Figure 8 In (C), the trajectory r is represented by a single-dot dashed line, and one of the two pressing surfaces 25 is located in the second direction closer to the contact portion C1 than the rotation center O of the output component 8. Figure 8 The pressing surface 25 (on the left side of (C)) tends to be forcefully pressed against the pressed surface 11 and thus engaged. In order to release the engagement of the pressing surface 25 with the pressed surface 11, the torque of the input component 7 increases instantaneously when switching from the locked state to the unlocked state.

[0153] Conversely, in the case of the reverse input cut-off clutch 4 as in this example, where the first distance D1 is smaller than the second distance D2 (D1 < D2), and the contact portion C1 is located on the side of the rotation center O of the output component 8 that is closer in the first direction than the imaginary straight line L, such as Figure 8As shown in (A), if a counterclockwise rotational torque is input to the input component 7, the engaging member 10 tends to rotate clockwise around the contact portion C1. However, as Figure 8 As shown by the dashed lines representing trajectories r1 and r2 in (A), neither of the pressing surfaces 25 presses against the pressed surface 11. Therefore, even when switching from the locked state to the unlocked state, the torque of the input component 7 does not increase instantaneously, allowing for a smooth transition from the locked state to the unlocked state. Furthermore, since no peak torque is generated, there is no need to unnecessarily increase the maximum output torque of the actuator 5, preventing unnecessary enlargement of the actuator 5.

[0154] Furthermore, the reverse input cut-off clutch can also include a resilient member that elastically applies force to the engaging member in the direction that brings the pressing surface closer to the pressed surface. This resilient member can be, for example, a torsion coil spring or a leaf spring. In the case where two engaging members are provided and the resilient member is a torsion coil spring, by utilizing the protrusion provided on the engaging member (in this example...) Figure 2 as well as Figures 4-7 The protrusion 30 shown is inserted into the end of the torsion coil spring, thereby also being able to hold the torsion coil spring.

[0155] The materials used for the input component, output component, pressed component, and engaging component of the reverse input cut-off clutch are not particularly limited. For example, in addition to metals such as iron alloys, copper alloys, and aluminum alloys, synthetic resins mixed with reinforcing fibers may also be used, depending on the need. Furthermore, the input component, output component, pressed component, and engaging component may be made of the same material or different materials.

[0156] [Second Example]

[0157] according to Figures 9-13 (B) will describe a second example of an embodiment of this disclosure.

[0158] In this example, the dimensions and shapes of the pressed part 9, the input part 7a, the output part 8a, and the two engaging parts 10 constituting the reverse input cut-off clutch 4a are modified based on the reverse input cut-off clutch 4 in the first example.

[0159] First, the output component 8a is directed in a predetermined direction (e.g.) Figure 9 As the input component 7a rotates clockwise, the two pressing surfaces 25 are pressed against the pressed surface 11, and the input component 7a rotates in the opposite direction to the predetermined direction (e.g., clockwise). Figure 9Rotating counterclockwise, the input-side engaging portion 12a is engaged with the input-side engaged portion 26, that is, a portion of the input-side engaging portion 12a is in contact with the input-side engaged portion 26, so that the contact portion P between the input-side engaging portion 12a and the input-side engaged portion 26 is... in The distance D1 between the rotation center O of the input component 7a and the first distance D1 in the second direction is greater than the contact portion P of the output-side engaging part 19a and the output-side engaged part 27. out The second distance D2 between the rotation center O of the output component 8a and the second distance D2 in the second direction is greater than (D1 > D2).

[0160] In addition, such as Figure 11 As shown, in the locked state where the output component 8a is subjected to a reverse rotational torque and the two pressing surfaces 25 of each engaging member 10 are in contact with the pressed surface 11, the contact portion C1 of the output-side engaging portion 19a and the output-side engaged portion 27 is located on the side closer to the rotation center O of the output component 8a in the first direction compared to the imaginary straight line L. Figure 9 (the lower side), the imaginary straight line connects one of the two pressing surfaces 25, specifically the pressing surface 25 on the side closer to the contact portion C1 than the rotation center O of the output component 8a in the second direction, and the abutting portion C2 of the pressed surface 11 to the rotation center O of the output component 8a.

[0161] In this example, when torque is input to the output component 8a in the opposite direction, by applying a torque to the input component 7a in the opposite direction to the torque input to the output component 8a, the reverse input cut-off clutch 4a can be switched to a state where torque can be transmitted between the input component 7a and the output component 8a. Specifically, by applying a torque to the input component 7a that is greater than or equal to a predetermined locking release torque in the opposite direction to the torque input to the output component 8a, the reverse input cut-off clutch 4a is switched to a state where torque input to the output component 8a in the opposite direction can be transmitted to the input component 7a.

[0162] After switching the reverse input cut-off clutch 4a to a state where it can transmit torque between the input component 7a and the output component 8a, a command is continuously given: to apply a torque to the input component 7a in the opposite direction to the torque input to the output component 8a, which is smaller than the torque input to the output component 8a, so that the torque input to the output component 8a in the opposite direction can be transmitted to the input component 7a.

[0163] Even in this example, after switching the reverse input cut-off clutch 4a to a state capable of transmitting torque between the input component 7a and the output component 8a, it is sufficient that the command value for the magnitude of the torque assigned to the input component 7a can prevent the reverse input cut-off clutch 4a from switching to a locked state. That is, once the reverse input cut-off clutch 4a switches to a locked-out state capable of transmitting torque between the input component 7a and the output component 8a, the command value for the torque assigned to the input component 7a can be made extremely small compared to the aforementioned locked-out torque.

[0164] In the reverse input cut-off clutch 4a of this example, the first distance D1 is made larger than the second distance D2, and in the locked state, the contact portion C1 is located on the side closer to the rotation center O of the output component 8a in the first direction than the imaginary straight line L. Therefore, the switching from the locked state to the unlocked state can be performed smoothly, and the switching from the unlocked state to the locked state can be performed quickly. (Refer to...) Figure 13 (A) and Figure 13 (B) Explains the reason.

[0165] When the reverse input cut-off clutch 4a is locked, if torque is input to the input component 7a, each engaging component 10 tends to rotate around the contact portion C1.

[0166] When the contact portion C1 is located on a side further away from the rotation center O of the output component 8a in the first direction than the imaginary straight line L, such as Figure 13 As shown in (B), if a counterclockwise rotational torque is input to the input component 7a, the engaging member 10 tends to rotate counterclockwise around the contact portion C1. Furthermore, as... Figure 13 In (B), the trajectory r is represented by a single-dot dashed line, and one of the two pressing surfaces 25 is located on the opposite side of the contact portion C1, separated from the rotation center O of the output component 8a in the second direction. Figure 13 The other pressing surface 25 on the right side of B) tends to be forcefully pressed against the pressing surface 11.

[0167] That is, when the contact portion C1 is located on the side further away from the rotation center O of the output component 8a in the first direction than the imaginary straight line L, the contact portion C1, which becomes the fulcrum, and the contact portion P, which becomes the force point, are... in Distance in the second direction (distance of force point) D p It becomes relatively large. On the other hand, the distance (distance between points of action) D between the contact portion C1 and the pressed surface 11 (which serves as the point of action) and the contact portion C3 of the other pressing surface 25 in the second direction. aThe force becomes relatively small. Therefore, according to the lever principle, the force exerted by the pressing surface 11 on the other pressing surface 25 increases, making it easier for the other pressing surface 25 to engage with the pressed surface 11. To release this engagement of the other pressing surface 25 with respect to the pressed surface 11, the rotational torque of the input component 7a momentarily becomes excessive when switching from the locked or semi-locked state to the unlocked or semi-unlocked state. That is, the instantaneous maximum torque (peak torque) of the input-side mechanism used to rotate the input component 7a becomes excessive.

[0168] Conversely, in the case of a reverse input cut-off clutch 4a as in this example, where the contact portion C1 is located on the side closer to the rotation center O of the output component 8a in the first direction than the imaginary straight line L, such as... Figure 13 As shown in (A), if a counterclockwise rotational torque is input to the input component 7a, the engaging member 10 also tends to rotate counterclockwise around the contact portion C1. Furthermore, as... Figure 13 In (A), the trajectory r is represented by a single-dot dashed line. The two pressing surfaces 25 are located on the opposite side of the contact portion C1, separated from the rotation center O of the output component 8a in the second direction. Figure 13 The other pressing surface 25 on the right side of (A) tends to be pressed against the pressing surface 11.

[0169] In this example, since the contact portion C1 is located on the side that is closer to the rotation center O of the output component 8a than the imaginary straight line L in the first direction, it is in harmony with... Figure 13 The structure shown in (B) is compared to the contact part C1, which becomes the fulcrum, and the contact part P, which becomes the force point. in Distance in the second direction (distance of force point) D p It gets smaller. Also, with Figure 13 The structure shown in (B) allows the distance (distance between points of action) between the contact portion C1 and the pressed surface 11 (which serves as the point of action) and the contact portion C3 of the other pressing surface 25 in the second direction to be equal. a It gets bigger. Therefore, with Figure 13 Compared to the structure shown in (B), the force exerted by the pressed surface 11 on the other pressing surface 25 is smaller, making it less likely for the other pressing surface 25 to engage with the pressed surface 11. Therefore, compared to Figure 13 Compared to the configuration shown in (B), the peak torque during the switch from the locked state to the unlocked state can be suppressed to a smaller extent. Therefore, in the reverse input cut-off clutch 4a of this example, the switch from the locked state to the unlocked state can be performed smoothly.

[0170] In the reverse input cut-off clutch 4a of this example, if torque is input to the input component 7a, the engaging member 10 tends to rotate around the contact portion C1, and the other pressing surface 25 tends to press against the pressed surface 11. Therefore, in the reverse input cut-off clutch 4a of this example, when torque is input in the reverse direction to the output component 8a, compared to the reverse input cut-off clutch 4 of the first example, the amount of movement of the engaging member 10 in the second direction required to press the pressing surface 25 against the pressed surface 11 can be reduced. Therefore, in the reverse input cut-off clutch 4a of this example, the switching from the locked-out state to the locked state can be performed quickly.

[0171] Even in the reverse input cut-off clutch 4a of this example, when it is desired to transmit the torque input in reverse to the output component 8a to the input component 7a, by applying a torque to the input component 7a in the opposite direction to the torque input in reverse to the output component 8a, the reverse input cut-off clutch 4a can be switched to a state where the torque input in reverse to the output component 8a can be transmitted to the input component 7a. Furthermore, by continuously applying a command to the input component 7a to a torque smaller than the torque input in reverse to the output component 8a and in the opposite direction to the torque input in reverse to the output component 8a, the torque input in reverse to the output component 8a is transmitted to the input component 7a. Therefore, even in the reverse input cut-off clutch 4a, which can quickly switch from the locked state to the locked state, the occurrence of jitter can be prevented.

[0172] The other structures and effects of the second example are the same as those of the first example.

[0173] Explanation of symbols

[0174] 1—Steering device; 2—Actuator with reverse input cut-off clutch; 3—Linear motion mechanism; 4, 4a—Reverse input cut-off clutch; 5—Actuator; 7, 7a—Input component; 8, 8a—Output component; 9—Pressed component; 10—Engaging component; 11—Pressed surface; 12, 12a—Input-side engagement part; 13—Base plate part; 14—Input shaft part; 15—Input handle part; 16—Radial inner surface; 17—Radial outer surface; 18—Circumferential side; 19, 19a —Output side engaging part, 20—Output shaft part, 21—Flange part, 22—Output handle part, 23—Flat surface, 24—Convex curved surface, 25—Pressing surface, 26—Input side engaging part, 27—Output side engaging part, 28—Flat surface, 29—Flat surface part, 30—Protrusion, 31—Rear wheel, 32—Rod, 33—Ball nut, 34—Ball, 35—Tie rod, 36—Steering knuckle arm, 37—Torque transmission mechanism, 38—Drive gear, 39—Intermediate gear, 40—Driven gear.

Claims

1. An actuator with a reverse input cut clutch, characterized by, have: Actuator; The controller controls the amount of electricity and the direction of electricity supplied to the aforementioned actuator; and A reverse input cut-off clutch comprises: a pressing member having a pressing surface on its inner circumferential surface; an input member having an input-side engagement portion disposed radially inward of the pressing surface and supported to be rotatable coaxially with the pressing surface and driven by an actuator; an output member having an output-side engagement portion disposed radially inward of the pressing surface compared to the input-side engagement portion and supported to be rotatable coaxially with the pressing surface and connected to an output-side mechanism in a manner capable of transmitting torque; and an engagement member having a pressing surface facing the pressing surface, an input-side engagement portion capable of engaging with the input-side engagement portion, and an output-side engagement portion capable of engaging with the output-side engagement portion, and configured to be movable in a first direction relative to the pressing surface in a proximal-rear direction. The aforementioned engaging member is configured such that, if torque is input to the input component from the actuator, the pressing surface moves away from the pressed surface in the first direction based on the engagement between the input-side engaging portion and the input-side engaged portion, thereby transmitting torque between the input component and the output component. Conversely, if torque is input to the output component from the output-side mechanism in the opposite direction when no torque is input to the input component from the actuator, the pressing surface is pressed in the first direction towards the pressed surface based on the engagement between the output-side engaged portion and the output-side engaging portion, causing frictional engagement between the pressing surface and the pressed surface. The aforementioned reverse input cut-off clutch is configured such that, when no reverse torque is input from the output-side mechanism to the output member, if torque is input from the actuator to the input member, the torque input to the input member is transmitted to the output member; conversely, when no torque is input from the actuator to the input member, if reverse torque is input from the output-side mechanism to the output member, the rotation of the output member is locked. Furthermore, the controller controls the input component to be in a state where a torque is input in the reverse direction from the output side mechanism to the output component. The actuator then applies a torque to the input component in the opposite direction to the torque input in the reverse direction from the output side mechanism to the output component, thereby switching the reverse input disengagement clutch to a state where torque can be transmitted between the input component and the output component. Afterward, the controller continuously applies a command to the input component to apply a torque in the opposite direction with a magnitude smaller than the torque input in the reverse direction from the output side mechanism to the output component, thereby transmitting the torque input in the reverse direction from the output side mechanism to the output component to the input component.

2. The actuator with an attached reverse input cut-off clutch according to claim 1, characterized in that, The aforementioned actuator is equipped with an electric motor.

3. The actuator with an attached reverse input cut-off clutch according to claim 1, characterized in that, The aforementioned engaging member has two pressing surfaces at two locations on its radially outer side that are separated in the circumferential direction.

4. The actuator with an attached reverse input cut-off clutch according to claim 3, characterized in that, When the output component rotates circumferentially to one side and the two pressing surfaces are pressed against the pressed surface, and when the input component rotates circumferentially to the other side and the input-side engaging portion engages with the input-side engaged portion, the distance between the contact portion of the input-side engaging portion and the input-side engaged portion in the second direction, which is orthogonal to both the first direction and the rotation center of the input component, and the rotation center of the input component, is smaller than the distance between the contact portion of the output-side engaging portion and the output-side engaged portion in the second direction and the rotation center of the output component. When the output component is input with reverse torque and the two pressing surfaces are in contact with the pressed surface, the contact portion of the output-side engaging portion and the output-side engaged portion is located on the side closer to the rotation center of the output component in the first direction compared to the imaginary straight line. This imaginary straight line connects one of the pressing surfaces and the abutting portion of the pressed surface to the rotation center of the output component.

5. The actuator with an attached reverse input cut-off clutch according to claim 3, characterized in that, When the output component rotates circumferentially to one side and the two pressing surfaces are pressed against the pressed surface, and when the input component rotates circumferentially to the other side and the input-side engaging portion engages with the input-side engaged portion, the distance between the contact portion of the input-side engaging portion and the input-side engaged portion in the second direction, which is orthogonal to both the first direction and the rotation center of the input component, and the rotation center of the input component, is greater than the distance between the contact portion of the output-side engaging portion and the output-side engaged portion in the second direction and the rotation center of the output component. When the output component is input with reverse torque and the two pressing surfaces are in contact with the pressed surface, the contact portion of the output-side engaging portion and the output-side engaged portion is located on the side closer to the rotation center of the output component in the first direction compared to the imaginary straight line. This imaginary straight line connects one of the pressing surfaces and the abutting portion of the pressed surface to the rotation center of the output component.

6. The actuator with an attached reverse input cut-off clutch according to claim 1, characterized in that, The aforementioned reverse input cut-off clutch has two engaging members, each composed of the aforementioned engaging member.

7. The actuator with an attached reverse input cut-off clutch according to claim 1, characterized in that, The aforementioned reverse input cut-off clutch includes an elastic member that elastically applies force to the engaging member in a direction that brings the pressing surface closer to the pressed surface.

8. A steering device characterized by comprising: have: An actuator with an attached reverse input cut-off clutch, having an output component; and A linear motion mechanism has a rod supported to perform linear motion and connected to the steering wheel in a manner that changes the orientation of the steering wheel according to the linear motion, and converts the rotational motion of the output component into the linear motion of the rod. The aforementioned actuator with an attached reverse input cut-off clutch is constituted by the actuator with an attached reverse input cut-off clutch as described in any one of claims 1 to 7.

9. The steering device according to claim 8, characterized in that, The aforementioned rod has a helical external ball screw groove on its outer circumferential surface. The aforementioned linear motion mechanism also has: A ball nut having a helical inner ball screw groove on its inner circumferential surface, driven by the aforementioned output component for rotation; and Multiple balls are arranged to roll freely between the outer ball screw groove and the inner ball screw groove.

10. The steering device according to claim 8, characterized in that, The aforementioned steering wheels are the rear wheels.

11. A control method for a reverse input cut-off clutch, the reverse input cut-off clutch comprising: a pressed member having a pressed surface on its inner peripheral surface; an input member having an input-side engagement portion disposed radially inward of the pressed surface and supported to be rotatable coaxially with the pressed surface and driven rotatably by an actuator; an output member having an output-side engagement portion disposed radially inward of the pressed surface compared to the input-side engagement portion and supported to be rotatable coaxially with the pressed surface and connected to an output-side mechanism in a manner capable of transmitting torque; and an engagement member having a pressed surface facing the pressed surface, an input-side engaged portion capable of engaging with the input-side engaged portion, and an output-side engaged portion capable of engaging with the output-side engaged portion, and configured to be movable in a first direction relative to the pressed surface in a proximal-rear direction. The aforementioned engaging member is configured such that, if torque is input to the input component from the actuator, the pressing surface moves away from the pressed surface in the first direction based on the engagement between the input-side engaging portion and the input-side engaged portion, thereby transmitting torque between the input component and the output component. Conversely, if torque is input to the output component from the output-side mechanism in the opposite direction when no torque is input to the input component from the actuator, the pressing surface is pressed in the first direction towards the pressed surface based on the engagement between the output-side engaged portion and the output-side engaging portion, causing frictional engagement between the pressing surface and the pressed surface. The aforementioned reverse input cut-off clutch is configured such that, when no reverse torque is input from the output-side mechanism to the output member, if torque is input from the actuator to the input member, the torque input to the input member is transmitted to the output member; conversely, when no torque is input from the actuator to the input member, if reverse torque is input from the output-side mechanism to the output member, the rotation of the output member is locked. The aforementioned control method for cutting off the clutch via reverse input is characterized by the following: When predetermined conditions are met, and in a state where torque is input in the reverse direction from the output-side mechanism to the output component, the actuator applies a torque to the input component in the opposite direction to the torque input in the reverse direction from the output-side mechanism to the output component, thereby switching the reverse input disengagement clutch to a state in which torque can be transmitted between the input component and the output component. Then, an instruction is continuously given to the actuator to apply a torque to the input component in the opposite direction, which is smaller than the torque input in the reverse direction from the output-side mechanism to the output component, thereby transmitting the torque input in the reverse direction from the output-side mechanism to the output component to the input component.

Images