Motor with reverse-input cutoff clutch, steering device, and method for controlling reverse-input cutoff clutch

Abstract

The present invention addresses the problem of realizing a motor with a reverse-input cutoff clutch, whereby the generation of abnormal noise when beginning the transmission of rotational torque from an input member to an output member can be prevented or suppressed. When an input member 8 begins to rotate in response to the input of rotational torque, until the input member 8 rotates by a limiting angle θL, the angular acceleration α of the input member 8 is regulated to a prescribed limited angular acceleration αL or less, or the angular velocity ω of the input member 8 is regulated to a prescribed limited angular velocity ωL or less, the limiting angle being the angle at which the generation of collision noise resulting from the collision of an input-side engaging part 18 with an input-side engaged part 37 and / or the generation of collision noise resulting from the collision of an output-side engaged part 38 with an output-side engaging part 24 can be prevented or suppressed.

Description

Motor with reverse input blocking clutch, steering device, and control method for reverse input blocking clutch

[0001] This disclosure relates to a motor with a reverse input blocking clutch that transmits rotational torque input to an input member to an output member, while blocking rotational torque input in the reverse direction to the output member; a steering device equipped with the motor with the reverse input blocking clutch; and a control method for the reverse input blocking clutch.

[0002] A reverse input blocking clutch transmits rotational torque input to an input member connected to an input-side mechanism such as a drive source to an output member connected to an output-side mechanism such as a reduction mechanism. In contrast, it has the function of completely blocking the rotational torque that is reverse-input to the output member and not transmitting it to the input member, or transmitting only a portion of it to the input member and blocking the rest.

[0003] Reverse input blocking clutches differ in the mechanism for blocking the rotational torque applied in reverse to the output member. They include a lock-type reverse input blocking clutch, which has a mechanism to prevent the output member from rotating when rotational torque is applied in reverse, and a free-type reverse input blocking clutch, which has a mechanism to allow the output member to spin freely when rotational torque is applied. The choice between a lock-type and a free-type reverse input blocking clutch is determined appropriately based on the application of the device in which the reverse input blocking clutch is incorporated.

[0004] In the lock-type reverse input blocking clutch described in International Publication No. 2019 / 026794, when rotational torque is input to an input member, the input-side engaging portion of the input member engages with the input-side engaged portion of the engaging element, causing the engaging element to move away from the pressed surface of the pressed member, and the output-side engaged portion of the engaging element engages with the output-side engaging portion of the output member, thereby transmitting the rotational torque input to the input member to the output member. On the other hand, when rotational torque is input in reverse to the output member, the output-side engaging portion engages with the output-side engaged portion, causing the engaging element to move towards the pressed surface, pressing the pressing surface of the engaging element against the pressed surface, and frictionally engaging the pressing surface with the pressed surface.

[0005] Various mechanical devices for automobile wheels (front wheels, rear wheels, or both), such as steering systems, utilize motors equipped with reverse input blocking clutches as drive motors to prevent torque from being transmitted from the output mechanism to the input mechanism, which is composed of a motor. In particular, steering systems are equipped with motors with reverse input blocking clutches to enable the application of steering angles to a pair of left and right steering wheels according to the amount of steering wheel operation, while preventing the transmission of shock torque due to the steering wheels riding over a curb, vibrations from the road surface, etc., to the motor.

[0006] International Publication No. 2019 / 026794

[0007] In the conventional reverse input shutoff clutch described in International Publication No. 2019 / 026794, the dimensional relationships of the parts are not particularly restricted, except that, at the position where the pressing surface of the engaging element contacts the pressed surface of the pressed member due to the reverse input of rotational torque to the output member, there is a gap between the input side engaged portion of the engaging element and the input side engaging portion of the input member that allows the pressing surface of the engaging element to be pressed against the pressed surface based on the engagement between the output side engaging portion of the engaging element and the output side engaged portion of the output member.

[0008] However, in conventional reverse input shut-off clutches, the dimensions of each part are restricted so that the input member, output member, and engaging element can be fitted together loosely to some extent, in order to prevent the shape precision of the input member, output member, and engaging element from being excessively high, and to ensure workability during assembly. As a result, it is unavoidable that circumferential gaps are formed between the input-side engaging portion of the input member and the input-side engaged portion of the engaging element, and between the output-side engaging portion of the output member and the output-side engaged portion of the engaging element.

[0009] The presence of such a circumferential gap may cause an unpleasant noise to be generated when the transmission of rotational torque from the input member to the output member begins, due to a collision between the input-side engaging portion and the input-side engaged portion, or between the output-side engaged portion and the output-side engaging portion. Such noises tend to be particularly noticeable when the direction of the rotational torque input to the input member reverses.

[0010] This disclosure aims to provide a motor structure with a reverse input blocking clutch, a steering device structure equipped with the motor with the reverse input blocking clutch, and a control method for the reverse input blocking clutch, which can prevent or suppress the generation of abnormal noise at the start of transmission of rotational torque from an input member to an output member.

[0011] A motor with a reverse input blocking clutch according to one aspect of the present disclosure comprises a motor, a controller, and a reverse input blocking clutch.

[0012] The motor has a motor output shaft.

[0013] The controller controls the rotation of the motor output shaft.

[0014] The reverse input blocking clutch comprises a pressed member, an input member, an output member, and an engaging element.

[0015] The member to be pressed has a surface to be pressed on its inner circumferential surface.

[0016] The input member has an input-side engaging portion located radially inward of the pressed surface, is arranged coaxially with the pressed surface, and is rotationally driven by the motor output shaft.

[0017] The output member has an output-side engaging portion that is located radially inward from the input-side engaging portion and is arranged coaxially with the pressed surface.

[0018] The engaging element has a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and is arranged to be movable in the radial direction.

[0019] When rotational torque is input from the motor output shaft to the input member, the engaging element moves radially away from the pressed surface based on the input side engaging portion engaging with the input side engaged portion, thereby engaging the output side engaged portion with the output side engaging portion and transmitting the rotational torque input to the input member to the output member. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output side engaging portion engaging with the output side engaged portion, causing the pressing surface to frictionally engage with the pressed surface.

[0020] The controller, when the transmission of rotational torque from the input member to the output member begins based on the input of rotational torque from the motor output shaft to the input member, has a limiting angle θ that prevents or suppresses the generation of collision noise due to the input side engaging portion colliding with the input side engaged portion, the generation of collision noise due to the output side engaged portion colliding with the output side engaging portion, or both. Ｌ Until it rotates by a certain amount, the angular acceleration α of the input member is a predetermined limiting angular acceleration α Ｌ The angular acceleration of the motor output shaft is controlled so that the angular velocity ω of the input member is set to a predetermined limit angular velocity ω. Ｌ The motor has a limiting function that controls the angular acceleration of the motor output shaft so that it behaves as follows.

[0021] In a motor with a reverse input blocking clutch according to one aspect of the present disclosure, the limiting angle θ Ｌ However, the angle θ from the state in which the pressing surface is in contact with the pressed surface and the input-side engaging portion is positioned at the circumferential center inside the input-side engaged portion, until the input-side engaging portion engages with the input-side engaged portion as the input member rotates to one side (for example, one clockwise or counterclockwise direction when viewed from one axial side) or to the other side (for example, the other clockwise or counterclockwise direction when viewed from one axial side) ｉｎAnd, in a state where the pressing surface is in contact with the pressed surface, the angle until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to one side thereof and the angle until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to the other side thereof, and the angle θ until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to one side or the other side thereof from a state where these angles are the same ｏｕｔ To the sum with a predetermined margin angle θ ｍ An angle (θ ｉｎ + θ ｏｕｔ + θ ｍ ) is obtained.

[0022] In the motor with a reverse input blocking clutch according to one aspect of the present disclosure, the limit angle θ Ｌ Is an angle 2θ from a state where the pressing surface is in contact with the pressed surface and the input-side engaging portion engages with the input-side engaged portion as the input member rotates to one side thereof until the input-side engaging portion engages with the input-side engaged portion by rotating the input member to the other side ｉｎ And an angle 2θ from a state where the pressing surface is in contact with the pressed surface and the output-side engaging portion engages with the output-side engaged portion as the output member rotates to the other side thereof until the output-side engaging portion engages with the output-side engaged portion by rotating the output member to the one side ｏｕｔ To the sum with a predetermined margin angle θ ｍ An angle (2θ ｉｎ + 2θ ｏｕｔ + θ ｍ ) is obtained.

[0023] In the motor with a reverse input blocking clutch according to one aspect of the present disclosure, in a state where the pressing surface is in contact with the pressed surface, the angle until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to one side thereof and the angle until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to the other side thereof, and the angle (θ until the output-side engaging portion engages with the output-side engaged portion as the output member rotates to one side or the other side thereof from a state where these angles are the same ｏｕｔ) is the angle (θ) from the state in which the pressing surface is in contact with the pressed surface and the input-side engaging portion is positioned at the circumferential center inside the input-side engaged portion, until the input-side engaging portion engages with the input-side engaged portion as the input member rotates to one side or the other side. ｉｎ It is smaller than ).

[0024] In a motor with a reverse input blocking clutch according to one aspect of the present disclosure, the controller does not perform the limiting function if the angular acceleration or angular velocity of the input member calculated based on an external input is greater than a predetermined threshold.

[0025] In a motor with a reverse input blocking clutch according to one aspect of the present disclosure, the engaging element has a convex curved surface portion on at least one of the portions of the input-side engaged portion that engages with the input-side engaging portion and the portion of the output-side engaged portion that engages with the output-side engaging portion.

[0026] A steering device according to one aspect of the present disclosure comprises a motor with a reverse input blocking clutch having an output member, and a linear motion mechanism having a rod connected to the steering wheel, which is supported to enable linear motion in the axial direction of the motor and which changes the direction of the steering wheel in accordance with the linear motion, and which converts the rotational motion of the output member into linear motion in the axial direction of the rod.

[0027] In particular, in a steering device according to one aspect of the present disclosure, the motor with reverse input blocking clutch is configured as a motor with reverse input blocking clutch according to one aspect of the present disclosure.

[0028] In a steering device according to one aspect of the present disclosure, the steering wheel is a rear wheel.

[0029] A reverse input interruption clutch to which a control method for a reverse input interruption clutch according to one aspect of the present disclosure applies comprises: a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion arranged radially inward from the pressed surface and arranged coaxially with the pressed surface; an output member having an output-side engaging portion arranged radially inward from the input-side engaging portion and arranged coaxially with the pressed surface; and an engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to be movable in the radial direction.

[0030] When rotational torque is input to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, thereby engaging the output-side engaged portion with the output-side engaging portion and transmitting the rotational torque input to the input member to the output member. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, causing the pressing surface to frictionally engage with the pressed surface.

[0031] In particular, in a control method for a reverse input shutoff clutch according to one aspect of the present disclosure, when the input member begins to rotate in response to the input of rotational torque, the input member has a limiting angle θ which is an angle that can prevent or suppress the generation of collision noise due to the input-side engaging portion colliding with the input-side engaged portion, the generation of collision noise due to the output-side engaged portion colliding with the output-side engaging portion, or both. Ｌ Until it rotates by a certain amount, the angular acceleration α of the input member is limited to a predetermined angular acceleration α. Ｌ The following restrictions are imposed, or the angular velocity ω of the input member is set to a predetermined limiting angular velocity ω Ｌ The following restrictions apply.

[0032] In a control method for a reverse input blocking clutch according to one aspect of the present disclosure, the limiting angle θ ＬThe angle θ from the state in which the pressing surface is in contact with the pressed surface and the input-side engaging portion is positioned at the circumferential center inside the input-side engaged portion, until the input-side engaging portion engages with the input-side engaged portion as the input member rotates to one side or the other. ｉｎ The following is a state in which the pressing surface is in contact with the pressed surface, and the angle from which the output side engaging portion engages with the output side engaged portion as the output member rotates to one side is the same as the angle from which the output side engaging portion engages with the output side engaged portion as the output member rotates to the other side, until the angle θ from which the output side engaging portion engages with the output side engaged portion as the output member rotates to one side or the other side ｏｕｔ The sum of the two is a predetermined margin angle θ. ｍ The angle (θ) added ｉｎ +θ ｏｕｔ +θ ｍ )

[0033] In a control method for a reverse input blocking clutch according to one aspect of the present disclosure, the limiting angle θ Ｌ The angle 2θ is defined as the state in which the pressing surface is in contact with the pressed surface, and the input side engaging portion engages with the input side engaged portion as the input member rotates to one side, until the input side engaging portion engages with the input side engaged portion as the input member is rotated to the other side. ｉｎ The angle 2θ is defined as the state in which the pressing surface is in contact with the pressed surface, and the output side engaging portion engages with the output side engaged portion as the output member rotates to the other side, until the output side engaging portion engages with the output side engaged portion as the output member is rotated to the one side. ｏｕｔ The sum of the two is a predetermined margin angle θ. ｍ The angle (2θ) added ｉｎ +2θ ｏｕｔ +θ ｍ )

[0034] According to a motor with a reverse input blocking clutch according to one aspect of the present disclosure, and a control method for a reverse input blocking clutch according to one aspect of the present disclosure, in particular, when the motor with a reverse input blocking clutch is incorporated into various mechanical devices such as steering devices, it is possible to prevent or suppress the generation of abnormal noise at the start of transmission of rotational torque from an input member to an output member.

[0035] Figure 1 is a schematic diagram showing a motor with a reverse input blocking clutch and steering device according to one embodiment of the present disclosure. Figure 2 is a cross-sectional view showing the reverse input blocking clutch removed from the motor with the reverse input blocking clutch. Figure 3 is a cross-sectional view taken along line I-I in Figure 2. Figure 4 is a cross-sectional view taken along line I-I in Figure 2 showing the state in which rotational torque is input to the input member, with the holding member and biasing member omitted. Figure 5 is a cross-sectional view taken along line I-I in Figure 2 showing the state in which rotational torque is input in reverse to the output member, with the holding member and biasing member omitted. Figure 6 is a front view showing the engaging element removed. Figure 7 shows the limiting angle θ Ｌ This is a schematic diagram illustrating the first example. Figure 8 shows the limiting angle θ Ｌ This is a schematic diagram illustrating the second example. Figure 9 shows the limiting angle θ Ｌ This is a schematic diagram illustrating the third example. Figure 10 shows the limiting angle θ Ｌ This is a schematic diagram to explain the fourth example.

[0036] A control method for a motor 1 with a reverse input blocking clutch, a steering device 2, and a reverse input blocking clutch 5 according to one embodiment of the present disclosure will be explained with reference to Figures 1 to 10.

[0037] [Motor with Reverse Input Blocking Clutch] The motor with reverse input blocking clutch 1 transmits the rotational torque input to the input member 8 to the output member 9, while the motor is equipped with a reverse input blocking clutch 5 that completely blocks the rotational torque that is input in reverse to the output member 9 and does not transmit it to the input member 8, or transmits only a portion of it to the input member 8 and blocks the rest. This motor can be suitably applied to drive motors for various mechanical devices such as steering devices 2. In the following description, although not limited to this, we will refer to an example in which the motor with reverse input blocking clutch 1 is applied to the drive motor of the rear wheel steering device 2 shown in Figure 1.

[0038] In the following description, unless otherwise specified, the axial, radial, and circumferential directions refer to the axial, radial, and circumferential directions of the pressed surface of the pressed member 7 of the reverse input blocking clutch 5. The axial, radial, and circumferential directions of the pressed surface coincide with the axial, radial, and circumferential directions of the input member 8, and also coincide with the axial, radial, and circumferential directions of the output member 9. Furthermore, one axial side refers to the input member 8 side (right side in Figures 1 and 2), and the other axial side refers to the output member 9 side (left side in Figures 1 and 2).

[0039] The direction of the pressing surface 36 of the engaging element 10 relative to the pressed surface 11 is defined as the first direction (up and down direction in Figures 3 to 6), and the direction perpendicular to both the axial direction of the pressed surface and the first direction is defined as the second direction (left and right direction in Figures 3 to 6). With respect to the engaging element 10, the direction coinciding with the first direction is defined as its radial direction (direction indicated by arrow A in Figure 4), and the direction coinciding with the second direction is defined as its width direction (direction indicated by arrow B in Figure 4). Furthermore, with respect to the width direction of the engaging element 10, the inside refers to the center side of the engaging element 10 in the width direction, and the outside refers to both sides of the engaging element 10 in the width direction.

[0040] One side of the rotational direction with respect to the input member 8, output member 9, or engaging element 10 is either clockwise or counterclockwise when viewed from one side of the axial direction, and the other side of the rotational direction with respect to these members is the other clockwise or counterclockwise direction, which is opposite to the one side of the rotational direction when viewed from one side of the axial direction.

[0041] The motor 1 with reverse input blocking clutch comprises a motor 3, a controller 4, and a reverse input blocking clutch 5.

[0042] <Motor> Motor 3 rotates the input member 8 of the reverse input blocking clutch 5. Motor 3 has a motor output shaft 6. Motor 3 is not limited to this, but can be made up of, for example, a servo motor, a stepping motor, etc.

[0043] <Controller> The controller 4 controls the rotation of the motor output shaft 6 based on external inputs such as the amount of steering wheel operation by the driver. Specifically, the controller 4 is configured to control the rotation direction of the motor output shaft 6, and at least one of angular acceleration and angular velocity. The controller 4 is not limited to this, but can be configured by a microcontroller such as an ECU (Electronic Control Unit).

[0044] <Basic Structure of Reverse Input Blocking Clutch> The reverse input blocking clutch 5 comprises a pressed member 7, an input member 8, an output member 9, and an engaging element 10. The reverse input blocking clutch 5 transmits the rotational torque input to the input member 8 to the output member 9, while the rotational torque reversed and input to the output member 9 is either completely blocked and not transmitted to the input member 8, or only a portion of it is transmitted to the input member 8 and the rest is blocked. As long as the reverse input blocking clutch 5 has the following basic structure, it can be widely applied to a motor 1 with a reverse input blocking clutch, regardless of its detailed structure, and its control method can be implemented.

[0045] Furthermore, the materials used to constitute the pressed member 7, input member 8, output member 9, or engaging element 10 can be metals such as iron alloys, copper alloys, or aluminum alloys, or synthetic resins mixed with reinforcing fibers as needed.

[0046] (Pressed member) The pressed member 7 has a pressed surface 11 on its inner circumferential surface.

[0047] The pressed member 7 is supported and fixed to a structural element that does not rotate even when the motor 1 with reverse input blocking clutch is in use, or it is integrally provided with the structural element so that its rotation is restrained. When the pressed member 7 is supported and fixed to the structural element, known means can be used for such support and fixing.

[0048] The pressed surface 11 constitutes the surface that contacts the pressing surface 36 of the engaging element 10 when the engaging element 10 moves radially outward, in the direction approaching the pressed surface 11. The pressed member 7 is not limited in shape as long as it is configured to have the pressed surface 11 on its inner circumferential surface. The pressed surface 11 is annular when viewed from the axial direction. The pressed surface 11 is not limited to this, but can have a cylindrical shape in which the inner diameter does not change with respect to the axial direction.

[0049] The input-side engaging portion 18 of the input member 8 and the output-side engaging portion 24 of the output member 9 are positioned radially inward of the pressed surface 11. The input-side engaging portion 18, the output-side engaging portion 24, and the engaging element 10 are rotatable radially inward of the pressed surface 11.

[0050] (Input Member) The input member 8 has an input-side engaging portion 18 located radially inward of the pressed surface 11, is coaxially positioned with the pressed surface 11, and is rotationally driven by the motor output shaft 6. That is, rotational torque is input to the input member 8 from the motor 3. Specifically, the input member 8 can be fixed to the motor output shaft 6 or can be formed by the motor output shaft 6. Alternatively, the input member 8 can be connected to the motor output shaft 6 via a reduction gear so as to be able to transmit torque. The input member 8 can be rotatably supported by the pressed member 7 or the structural element.

[0051] The input-side engaging portion 18 is provided on a part of the input member 8 that is radially outward from the center of rotation, and has a portion that engages, specifically contacts, with the input-side engaged portion 37 of the engaging element 10. The input-side engaging portion 18 is configured to engage (contact) its radially inner surface 19 with the radially inner surface of the input-side engaged portion as the input member 8 or engaging element 10 rotates.

[0052] The outer circumferential surface of the input-side engaging portion 18 can have any configuration as long as it has a portion that engages with the input-side engaged portion 37. For example, it can have end face shapes such as a roughly fan-shaped, roughly trapezoidal, or arched shape, where the circumferential width increases towards the radially outward direction when viewed from the axial direction. From the standpoint of reducing the manufacturing cost of the input member 8, it is preferable that the outer circumferential surface of the input-side engaging portion 18 consists only of a flat radially inward surface 19 and a partially cylindrical radially outward surface 20 centered on the central axis of the input member 8.

[0053] The number of input-side engaging portions 18 is determined according to the number of engaging elements 10. If the engaging element 10 is composed of multiple engaging elements 10, the input-side engaging portions 18 are also composed of multiple input-side engaging portions 18.

[0054] (Output Member) The output member 9 has an output-side engaging portion 24 that is located radially inward from the input-side engaging portion 18, and is arranged coaxially with the pressed surface 11. That is, the output member 9 is also arranged coaxially with the input member 8. The output member 9 can be rotatably supported by the pressed member 7 or the structural element via a rolling bearing or the like.

[0055] The output member 9 is connected to an output-side mechanism such as a reduction gear mechanism, and is configured to output rotational torque to the output-side mechanism as it rotates. Specifically, the output member 9 can be formed from the input shaft of the output-side mechanism, or it can be formed as a separate component from the input shaft and fixed coaxially to the input shaft.

[0056] The output-side engaging portion 24 has a portion that engages with the output-side engaged portion 38 of the engaging element 10. This engaging portion is located radially inward from the input-side engaging portion 18 and radially outward from the central axis of the output member 9, and is positioned to engage with the output-side engaged portion 38 of the engaging element 10. The output-side engaging portion 24 is configured to engage (contact) its outer circumferential surface with the output-side engaged portion 38 as the output member 9 or the engaging element 10 rotates.

[0057] The output-side engaging portion 24 has a cam function. The distance from the rotational center axis of the output member 9 to the outer circumferential surface of the output-side engaging portion 24, which is the part that engages with the output-side engaged portion 38, is not constant in the circumferential direction. As a result, when rotational torque is input in reverse to the output member 9, the output-side engaging portion 24 can press the engaging element 10 in the radial direction of the engaging element 10, which is the first direction, as the output member 9 rotates.

[0058] The number of parts of the output-side engaging portion 24 that engage with the output-side engaged portion 38 is determined according to the number of engaging elements 10. If the engaging element 10 is composed of multiple engaging elements 10, the output-side engaging portion 24 is also configured to have multiple engaging parts.

[0059] For example, if there are two engaging elements 10, the output-side engaging portion 24 can be configured to have a portion that engages with two output-side engaged portions 38. However, even if there is only one engaging element 10, it is possible to adopt a structure having two or more output-side engaged portions 38.

[0060] The outer circumferential surface of the output-side engaging portion 24 can adopt any configuration as long as the output-side engaging portion 24 has a cam function, and its shape is appropriately set according to the number of parts of the output-side engaging portion 24 that engage with the output-side engaged portion 38. The output-side engaging portion 24 can be, for example, a roughly rectangular, roughly oval, parallelogram, trapezoid, or the like. However, from the viewpoint of reducing the manufacturing cost of the output member 9, it is preferable that the outer circumferential surface of the output member 9 has a flat surface portion 25 in the part that engages with the output-side engaged portion 38, and it is even more preferable that it is composed of a flat surface portion 25 and a partially cylindrical surface portion 26 centered on the central axis of the output member 9. Furthermore, it is preferable that the part of the flat surface portion 25 located in the axial middle and widthwise middle constitutes the part that engages with the output-side engaged portion 38.

[0061] (Engaging element) The engaging element 10 has a pressing surface 36 facing the pressed surface 11, an input-side engaged portion 37 that can engage with the input-side engaging portion 18, and an output-side engaged portion 38 that can engage with the output-side engaging portion 24, and is arranged to allow radial movement of the engaging element 10. The pressing surface 36 is provided on the radially outer surface of the engaging element 10 that faces the pressed surface 11.

[0062] When rotational torque is input to the input member 8, the engaging element 10 moves radially away from the pressed surface 11 based on the input-side engaging portion 18 engaging with the input-side engaged portion 37, and transmits the rotational torque input to the input member 8 to the output member 9 by engaging the output-side engaged portion 38 with the output-side engaging portion 24. Conversely, when rotational torque is input in reverse to the output member 9, the engaging element 10 is configured to press the pressing surface 36 against the pressed surface 11 based on the output-side engaging portion 38 engaging with the output-side engaged portion 24, thereby frictionally engaging the pressing surface 36 with the pressed surface 11.

[0063] The pressing surface 36 preferably has a surface property that results in a higher coefficient of friction with respect to the pressed surface 11 than the other parts of the engaging element 10. Furthermore, the pressing surface 36 can be integrally formed with the other parts of the engaging element 10, or it can be formed from the surface of a friction material fixed to the other parts of the engaging element 10 by adhesive or bonding.

[0064] The engaging element 10 may have one or more pressing surfaces 36, preferably two pressing surfaces 36.

[0065] The input-side engaged portion 37 is composed of a through hole provided in the radially intermediate portion of the widthwise center of the engaging element 10, or a recess that is recessed radially inward from the widthwise intermediate portion of the radially outer surface, and is sized to allow the input-side engaged portion 18 to be loosely inserted. Therefore, when the input-side engaged portion 18 is inserted inside the input-side engaged portion 37, there are gaps between the input-side engaged portion 18 and the inner surface of the input-side engaged portion 37 in the widthwise and radial directions of the engaging element 10. As a result, the input-side engaged portion 18 can be displaced relative to the input-side engaged portion 37 in the rotational direction of the input member 8, and the input-side engaged portion 37 can be displaced radially relative to the input-side engaged portion 18 of the engaging element 10.

[0066] The output-side engaged portion 38 is provided at the center of the width direction of the radially inner surface of the engaging element 10. The shape of the output-side engaged portion 38 is not limited as long as it is configured to engage with the output-side engaged portion 24.

[0067] The engaging element 10 can consist of one engaging element 10 or two or more engaging elements 10, as long as it has the above configuration.

[0068] The shape of the engaging element 10 is arbitrary as long as it comprises a pressing surface 36, an input-side engaged portion 37, and an output-side engaged portion 38, and can perform the functions described above.

[0069] <Operation of the Reverse Input Blocking Clutch> The operation of the reverse input blocking clutch 5 will be explained using Figures 4 and 5. Note that in Figures 4 and 5, the radial gap between the input member 8 and the output member 9 and the engaging element 10 is exaggerated.

[0070] When rotational torque is applied to the input member 8, the engaging element 10 moves away from the pressed surface 11, regardless of the rotational direction of the input member 8. More specifically, as shown in Figure 4, the input-side engaging portion 18 rotates inside the input-side engaged portion 37 in the rotational direction of the input member 8 (counterclockwise in the example of Figure 4).

[0071] This reduces the gap between the radially inner surface 19 of the input-side engaging portion 18 and the radially inner surface 41 of the input-side engaged portion 37, causing the radially inner surface 19 of the input-side engaging portion 18 to come into contact with the radially inner surface 41 of the input-side engaged portion 37.

[0072] From this state, as the input member 8 rotates further, the radially inner surface 19 of the input-side engaging portion 18 presses the radially inner surface 41 of the input-side engaged portion 37 radially inward, causing the engaging element 10 to move away from the pressed surface 11. That is, the engaging element 10 moves radially inward based on its engagement with the input member 8, bringing the output-side engaged portion 38 of the engaging element 10 into contact with the output-side engaging portion 24 of the output member 9, pressing the output-side engaging portion 24 to one side in the rotational direction, and causing the output member 9 to rotate.

[0073] Furthermore, the output member 9 is rotated until the flat surface portion 25 of the output-side engaging portion 24 is parallel to the connecting surface portion 46 of the output-side engaged portion 38, thereby ensuring that the output-side engaging portion 24 and the output-side engaged portion 38 of the engaging element 10 are engaged without any rattle. As a result, the rotational torque input to the input member 8 is transmitted to the output member 9 via the two engaging elements 10 and output from the output member 9.

[0074] When rotational torque is input in reverse to the output member 9, the engaging element 10 moves toward the pressed surface 11, regardless of the rotation direction of the output member 9. Specifically, as shown in Figure 5, the output-side engaging portion 24 rotates in the rotation direction of the output member 9 (clockwise in the example of Figure 5), pressing the output-side engaged portion 38 radially outward. As a result, the engaging element 10 moves toward the pressed surface 11.

[0075] In this way, the engaging element 10 moves radially outward based on its engagement with the output member 9, and the pressing surface 36 of the engaging element 10 comes into contact with the pressed surface 11, and frictionally engages with the pressed surface 11. As a result, the rotational torque that is reverse-input to the output member 9 is completely blocked and not transmitted to the input member 8, or only a portion of the rotational torque that is reverse-input to the output member 9 is transmitted to the input member 8 and the rest is blocked.

[0076] In order to completely block the rotational torque that is reverse-input to the output member 9 and prevent it from being transmitted to the input member 8, the engaging element 10 is braced (clamped) between the output-side engaging part 24 and the pressed member 7 so that the pressing surface 36 of the engaging element 10 does not slide (rotate relative to) the pressed surface 11, thereby locking the output member 9.

[0077] To ensure that only a portion of the rotational torque inverted to the output member 9 is transmitted to the input member 8 and the remainder is blocked, the engaging element 10 is braced (clamped) between the output-side engaging portion 24 and the pressed member 7 so that the pressing surface 36 of the engaging element 10 slides against the pressed surface 11, thereby partially locking the output member 9.

[0078] In the reverse input blocking clutch 5, the size of the gaps between each component is adjusted so that the above operations can be performed. In particular, when the pressing surface 36 of the engaging element 10 is in contact with the pressed surface 11, a gap exists between the radially inner surface 19 of the input-side engaging portion 18 and the radially inner surface 41 of the input-side engaged portion 37.

[0079] This prevents the radially outward movement of the engaging element 10 from being blocked by the input-side engaging portion 18 when rotational torque is input in reverse to the output member 9, and also ensures that even after the pressing surface 36 contacts the pressed surface 11, the surface pressure acting on the contact portion between the pressing surface 36 and the pressed surface 11 changes according to the magnitude of the rotational torque input in reverse to the output member 9, thereby ensuring that the output member 9 is properly locked or partially locked.

[0080] [Controller Limiting Function (Control Method for Reverse Input Blocking Clutch)] The motor 1 with a reverse input blocking clutch is characterized in that the controller 4 has a limiting function that controls the reverse input blocking clutch 5 as follows. The limiting function is an angle that prevents or suppresses the generation of collision noise due to the input side engaging portion 18 colliding with the input side engaged portion 37, the generation of collision noise due to the output side engaged portion 38 colliding with the output side engaging portion 24, or both, when the transmission of rotational torque from the input member 8 to the output member 9 begins based on the input of rotational torque from the motor output shaft 6 to the input member 8 (including when the rotation direction of the input member 8 is reversed), by the input member 8, when the input side engaging portion 18 colliding with the input side engaged portion 37, the generation of collision noise due to the output side engaged portion 38 colliding with the output side engaging portion 24, or both. Ｌ Until it rotates by that amount, the angular acceleration α of the input member 8 is a predetermined limiting angular acceleration α Ｌ The angular acceleration of the motor output shaft 6 is controlled so that the angular velocity ω of the input member 8 is set to a predetermined limit angular velocity ω. Ｌ The angular velocity of the motor output shaft 6 is controlled as follows:

[0081] Limiting angle θ Ｌ Preferably, the limiting angle θ is slightly greater than the sum of the rotation angle of the input member 8 from the time the input member 8 begins to rotate until the input-side engaging portion 18 collides with the input-side engaged portion 37, and the rotation angle of the input member 8 from the time the engaging element 10 begins to move radially inward until the output-side engaged portion 38 collides with the output-side engaging portion 24. Ｌ Even if the sum is less than or equal to the above, the force of the collision between the input-side engaging portion 18 and the input-side engaged portion 37, the force of the output-side engaged portion 38 and the output-side engaging portion 24, or both, can be mitigated, thus providing a certain degree of effectiveness.

[0082] Limiting angle θＬ This can be set to a predetermined angle.

[0083] Specifically, the limiting angle θ Ｌ Although not limited to this, for example, as shown in Figure 7, the angle θ (hereinafter referred to as the "input side angle") from a state in which the pressing surface 36 is in contact with the pressed surface 11 and the input side engaging portion 18 is positioned at the circumferential center inside the input side engaged portion 37, until the input side engaging portion 18 engages (contacts) with the input side engaged portion 37 as the input member 8 rotates to one side (for example, clockwise in Figure 7) or the other side (for example, counterclockwise in Figure 7) ｉｎ In the state where the pressing surface 36 is in contact with the pressed surface 11, the angle from which the output side engaging portion 24 engages (contacts) the output side engaged portion 38 as the output member 9 rotates to one side and the angle from which the output side engaging portion 24 engages (contacts) the output side engaged portion 38 as the output member 9 rotates to the other side is the same, and the angle from which the output side engaging portion 24 engages (contacts) the output side engaged portion 38 as the output member 9 rotates to one side or the other (hereinafter referred to as the "output side angle") θ ｏｕｔ The sum of the two is a predetermined margin angle θ. ｍ The angle (θ) added ｉｎ +θ ｏｕｔ +θ ｍ ) can be done as follows.

[0084] Furthermore, when the pressing surface 36 is in contact with the pressed surface 11, and the input-side engaging portion 18 is positioned at the circumferential center inside the input-side engaged portion 37, the angle at which the input-side engaging portion 18 engages (contacts) with the input-side engaged portion 37 as the input member 8 rotates to one side is the same as the angle at which the input-side engaging portion 18 engages (contacts) with the input-side engaged portion 37 as the input member 8 rotates to the other side.

[0085] Furthermore, in this example, when the pressing surface 36 is in contact with the pressed surface 11, and the angle at which the output side engaging portion 24 engages (contacts) with the output side engaged portion 38 as the output member 9 rotates to one side is the same as the angle at which the output side engaging portion 24 engages (contacts) with the output side engaged portion 38 as the output member 9 rotates to the other side, the flat surface portion 25 of the output side engaging portion 24 and the connecting surface portion 46 of the output side engaged portion 38 are arranged in parallel.

[0086] As a result, when the transmission of rotational torque from the input member 8 to the output member 9 begins from the state shown in Figure 7, or when the input member 8 starts rotating until the input-side engaging portion 18 collides with the input-side engaged portion 37, the sum of the rotation angle of the input member 8 from when the engaging element 10 starts moving radially inward until the output-side engaged portion 38 collides with the output-side engaging portion 24 is the angle (θ) ｉｎ +θ ｏｕｔ +θ ｍ When the value is smaller than ), it is possible to prevent or suppress the generation of collision noise due to the input-side engaging portion 18 colliding with the input-side engaged portion 37, the generation of collision noise due to the output-side engaged portion 38 colliding with the output-side engaging portion 24, or both.

[0087] Furthermore, the sum of the rotation angle of the input member 8 from the time the input member 8 begins to rotate until the input-side engaging portion 18 collides with the input-side engaged portion 37, and the rotation angle of the input member 8 from the time the engaging element 10 begins to move radially inward until the output-side engaged portion 38 collides with the output-side engaging portion 24, is equal to the angle (θ ｉｎ +θ ｏｕｔ +θ ｍ Even if the force is greater than ), the force of the collision between the input-side engaging portion 18 and the input-side engaged portion 37, the force of the output-side engaged portion 38 and the output-side engaging portion 24, or both, can be mitigated, thereby suppressing the generation of collision noise.

[0088] Limiting angle θ ＬAs shown in Figure 9, the input side engaging portion 18 engages (contacts) with the input side engaged portion 37 as the input member 8 is rotated to one side (clockwise in Figure 9), and the angle (angle θ) from the input side engaging portion 18 to the input side engaged portion 37 as the input member 8 is rotated to the other side (counterclockwise in Figure 9) is the angle (angle θ) on the input side. ｉｎ (Twice the angle) 2θ ｉｎ Then, the pressing surface 36 is brought into contact with the pressed surface 11, and as the output member 9 rotates to the other side, the output side engaging portion 24 engages (contacts) with the output side engaged portion 38. From this state, the angle (angle θ) is such that the output side engages (contacts) with the output side engaged portion 24 when the output member 9 is rotated to one side. ｏｕｔ (Twice the angle) 2θ ｏｕｔ The sum of the two is a predetermined margin angle θ. ｍ The angle (2θ) added ｉｎ +2θ ｏｕｔ +θ ｍ ) is preferable.

[0089] This makes it possible to prevent or suppress the generation of collision noise caused by the input-side engaging portion 18 colliding with the input-side engaged portion 37, the generation of collision noise caused by the output-side engaged portion 38 colliding with the output-side engaging portion 24, or both, regardless of the circumferential positional relationship of the input member 8, the output member 9, and the engaging element 10.

[0090] Alternatively, if the circumferential phase of the input member 8, output member 9, and engaging element 10 can be measured by a sensor (not shown), then the limiting angle θ Ｌ This can also be determined each time based on the circumferential phases of the input member 8, the output member 9, and the engaging element 10.

[0091] For example, as shown in Figure 7, when the pressing surface 36 is in contact with the pressed surface 11, the input-side engaging portion 18 is located at the circumferential center inside the input-side engaged portion 37, and the angle at which the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to one side is the same as the angle at which the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to the other side, the limiting angle θ is constant regardless of the rotation direction of the input member 8.Ｌ with the input side having an angle θ ｉｎ and the output side having an angle θ ｏｕｔ and adding a predetermined margin angle θ ｍ to the sum of the angles, the angle (θ ｉｎ + θ ｏｕｔ + θ ｍ ) can be used.

[0092] As shown in FIG. 8, when the pressing surface 36 abuts against the pressed surface 11, the input-side engaging portion 18 engages (contacts) with the input-side engaged portion 37 as the input member 8 rotates to one side, and the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to one side. Until the angle and the angle until the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to the other side are the same, when the rotation direction of the input member 8 is on one side, the limit angle θ Ｌ is the angle obtained by adding a predetermined margin angle θ ｏｕｔ to the angle θ ｍ [[ID=双22]]of the output side (θ ｏｕｔ + θ ｍ ). On the other hand, when the rotation direction of the input member 8 is on the other side, the limit angle θ Ｌ is the sum of twice the angle θ ｉｎ of the input side and the angle θ ｏｕｔ of the output side, plus a predetermined margin angle θ ｍ The angle obtained by adding (2θ ｉｎ + θ ｏｕｔ + θ ｍ ) can be used.

[0093] As shown in FIG. 9, when the pressing surface 36 abuts against the pressed surface 11, the input-side engaging portion 18 engages (contacts) with the input-side engaged portion 37 as the input member 8 rotates to one side, and the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to the other side. In this state, when the rotation direction of the input member 8 is on one side, the limit angle θ Ｌ can be the predetermined margin angle θ ｍ . On the other hand, when the rotation direction of the input member 8 is on the other side, the limit angle θ Ｌ is twice the angle θ ｉｎ of the input side and the angle θ ｏｕｔThe sum with twice that value is added with a predetermined margin angle θ ｍ to obtain an angle (2θ ｉｎ + 2θ ｏｕｔ + θ ｍ ).

[0094] As shown in FIG. 10, when the pressing surface 36 abuts against the pressed surface 11, the input-side engaging portion 18 is located at the circumferential center position inside the input-side engaged portion 37, and as the output member 9 rotates to the other side, the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38. When the rotation direction of the input member 8 is on one side, the limit angle θ Ｌ is set to an angle obtained by adding a predetermined margin angle θ ｉｎ to the angle θ ｍ on the input side (θ ｉｎ + θ ｍ ). On the other hand, when the rotation direction of the input member 8 is on the other side, the limit angle θ Ｌ is set to an angle obtained by adding a predetermined margin angle θ ｉｎ to the sum of the angle θ ｏｕｔ on the input side and twice the angle θ ｍ on the output side (θ ｉｎ + 2θ ｏｕｔ + θ ｍ ).

[0095] After the input member 8 rotates by the limit angle θ Ｌ , the controller 4 can control the rotation of the motor output shaft 6 based on an external input such as the operation amount of the steering wheel by the driver. Specifically, the angular acceleration α of the input member 8 can be increased to be greater than the limit angular acceleration α Ｌ and rapidly increased to the target angular acceleration, or the angular velocity ω of the input member 8 can be increased to be greater than the limit angular velocity ω Ｌ and rapidly increased to the target angular velocity.

[0096] Furthermore, the controller 4 can be configured not to execute the limiting function if the angular acceleration α or angular velocity ω of the input member 8, calculated based on external input, is greater than a predetermined threshold. In this case, for example, when a vehicle equipped with a steering device 2 to which a motor with a reverse input blocking clutch 1 is applied makes a sudden turn to avoid an obstacle, the responsiveness of the steering angle applied to the steering wheels 54 can be ensured.

[0097] Additionally or alternatively, the system can be configured so that the limiting function (control function of the reverse input blocking clutch 5) by the controller 4 can be switched on or off by a switch operation by the user, driver, or other user.

[0098] The structure of the reverse input blocking clutch 5 that constitutes the motor 1 with reverse input blocking clutch is arbitrary as long as it has the basic structure described above. Hereinafter, although not limited thereto, an example of a preferred configuration for the motor 1 with reverse input blocking clutch and the reverse input blocking clutch 5 of this example will be described.

[0099] (Relationship between input-side angle and output-side angle) In the motor 1 with reverse input blocking clutch of this example, as shown in Figure 7, with the pressing surface 36 in contact with the pressed surface 11, the angle from which the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to one side (for example, clockwise in Figure 7) and the angle from which the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to the other side (for example, counterclockwise in Figure 7) are the same, and the angle from which the output-side engaging portion 24 engages (contacts) with the output-side engaged portion 38 as the output member 9 rotates to one side or the other (output-side angle) θ ｏｕｔ The angle (input-side angle) θ is the angle from a state in which the pressing surface 36 is in contact with the pressed surface 11 and the input-side engaging portion 18 is positioned at the circumferential center inside the input-side engaged portion 37 until the input-side engaging portion 18 engages (contacts) with the input-side engaged portion 37 as the input member 8 rotates to one side or the other. ｉｎ It is made smaller than (θ ｏｕｔ <θ ｉｎ ).

[0100] This prevents or suppresses the generation of collision noise caused by the output-side engaged portion 38 colliding with the output-side engaged portion 24 when the transmission of rotational torque from the input member 8 to the output member 9 begins.

[0101] When rotational torque is applied from the motor output shaft 6 to the input member 8, first the gap between the radially inner surface 19 of the input-side engaging portion 18 and the radially inner surface 41 of the input-side engaged portion 37 (the gap located on the front side of the input-side engaging portion 18 with respect to the rotational direction of the input member 8) decreases, and the radially inner surface 19 of the input-side engaging portion 18 comes into contact with the radially inner surface 41 of the input-side engaged portion 37. From this state, as the input member 8 rotates further, the radially inner surface 19 of the input-side engaging portion 18 presses the radially inner surface 41 of the input-side engaged portion 37 radially inward.

[0102] This releases the frictional engagement between the pressing surface 36 of the engaging element 10 and the pressed surface 11 of the pressed member 7. Subsequently, as the input member 8 rotates, the radially inner surface 19 of the input-side engaging portion 18 further presses the radially inner surface 41 of the input-side engaged portion 37 radially inward, causing the engaging element 10 to move radially inward, and the output-side engaged portion 38 of the engaging element 10 engages with the output-side engaging portion 24 of the output member 9. This enables torque transmission from the input member 8 to the output member 9.

[0103] When the frictional engagement between the pressing surface 36 of the engaging element 10 and the pressed surface 11 of the pressed member 7 is released, the rotational torque of the input member 8 increases instantaneously, i.e., a peak torque is generated. If the amount of radial inward movement of the engaging element 10 due to being pressed by the input member 8 is large while such a large inertial force due to rotational torque is acting on the input member 8, the output side engaged portion 38 may engage forcefully with the output side engaging portion 24, i.e., the flat surface portion 25 of the output side engaging portion 24 may forcefully contact (collide) with the connecting surface portion 46 of the output side engaged portion 38, potentially generating an unpleasant noise.

[0104] In the motor 1 with reverse input blocking clutch, the output side is at an angle θ. ｏｕｔ The input side is at an angle θ ｉｎ It is made smaller than (θ ｏｕｔ >θ ｉｎTherefore, when a large inertial force acts on the input member 8 as a result of releasing the frictional engagement between the pressing surface 36 and the pressed surface 11, the amount of radial inward movement of the engaging element 10 can be kept small. As a result, the generation of abnormal noise due to collision between the output-side engaged portion 38 and the output-side engaging portion 24 can be prevented or suppressed.

[0105] (Pressed Member) In this example, the pressed member 7 includes a housing element 12 as an optional element that is supported and fixed to the structural element.

[0106] The housing element 12 has a stepped cylindrical inner surface. Specifically, the inner surface of the housing element 12 is formed by connecting a large-diameter cylindrical surface portion 13 on one axial side and a small-diameter cylindrical surface portion 14 on the other axial side with a connecting surface portion 15 facing one axial side. In this example, the large-diameter cylindrical surface portion 13 constitutes the pressed surface 11.

[0107] Furthermore, the housing element 12 has an inwardly projecting flange portion 16 at the axial end of the small-diameter cylindrical surface portion 14 that protrudes radially inward, and has screw holes 17 opening at multiple locations in the circumferential direction on the side surface on the axial side. The pressed member 7 in this example is supported and fixed to the structural element by screwing a bolt, which is inserted through a through hole provided in the structural element, into the screw hole 17.

[0108] The pressed member 7 may also include another housing element that closes the opening on one axial side of the housing element 12. In this case, the pressed member 7 can be constructed by fitting the other housing element to the axial end of the housing element 12 without any play (spigot fitting), thereby positioning the housing element 12 and the other housing element radially, and then connecting the housing element 12 and the other housing element with a connecting member such as a bolt.

[0109] (Input Member) In this example, the input member 8 is fixed to the motor output shaft 6.

[0110] In this example, the outer circumferential surface of the input-side engaging portion 18 consists only of a flat radial inner surface 19 and a partially cylindrical radial outer surface 20. That is, the input-side engaging portion 18 has an arc-shaped end face when viewed from the axial direction. The radial inner surface 19 and the radial outer surface 20 are connected by a pointed edge 21.

[0111] In this example, when manufacturing the input member 8 having the input-side engaging portion 18, it is not necessary to perform machining on the connection between the radially inner surface 19 and the radially outer surface 20 of the input-side engaging portion 18. For example, the input member 8 can be manufactured by forging a metal material to form its outer shape, and then performing finishing processes such as grinding as needed. This reduces the manufacturing cost of the input member 8. However, the input member 8 can also be manufactured by machining a metal material, including cutting. Furthermore, the radially inner surface 19 and the radially outer surface 20 can be connected by chamfered portions such as corner chamfers and rounded chamfers.

[0112] In this example, the input member 8 has, in addition to the input-side engaging portion 18, an input shaft portion 22 and an input flange portion 23.

[0113] The input shaft portion 22 has a cylindrical or columnar shape depending on the shape of the motor output shaft 6. In this example, the input shaft portion 22 has a cylindrical shape and is fixed to the motor output shaft 6.

[0114] The input flange portion 23 is an element for positioning the input-side engaging portion 18 at a location radially outward from the rotation center of the input member 8. The input flange portion 23 can be fixed to the output shaft of the input-side mechanism or to the input shaft portion 22, or it can be integrally formed with it. In this example, the input flange portion 23 protrudes radially outward from the outer circumferential surface of the other axial end of the input shaft portion 22 over its entire circumference.

[0115] The input-side engaging portion 18 protrudes axially toward the other side from the portion of the input flange portion 23 that is radially outward from the center of rotation on the other axial side.

[0116] In this example, since the engaging element 10 is composed of two engaging elements 10, the input-side engaging portion 18 is composed of two input-side engaging portions 18, corresponding to the number of engaging elements 10. The two input-side engaging portions 18 are positioned at two radially opposite locations on the other axial side of the input flange portion 23, and are spaced apart from each other with respect to the radial direction of the input member 8.

[0117] In this example, the input member 8 is positioned coaxially with the pressed surface 11, with the input shaft portion 22 fixed to the motor output shaft 6, and the motor output shaft 6 being rotatably supported by the structural element via radial bearings (not shown) and a motor housing.

[0118] (Output member) In this example, the axial width of the output-side engaging portion 24 is greater than the axial width of the engaging element 10.

[0119] In this example, the output-side engaging portion 24 is configured to have portions that engage with two output-side engaged portions 38, corresponding to the number of engaging elements 10.

[0120] In this example, the outer circumferential surface of the output-side engaging portion 24 is composed of two parallel flat surfaces 25 and two partially cylindrical surfaces 26. The output-side engaging portion 24 is symmetrical with respect to a virtual plane that passes through the rotational axis of the output member 9 and is perpendicular to the two flat surfaces 25. Furthermore, the output-side engaging portion 24 is symmetrical with respect to a virtual plane that passes through the rotational axis of the output member 9 and is parallel to the two flat surfaces 25. In other words, the output-side engaging portion 24 has a shape that is twice symmetrical with respect to the central axis of the output member 9. The flat surfaces 25 and the partially cylindrical surfaces 26 are connected by a pointed edge 66.

[0121] Therefore, when manufacturing the output member 9 having the output-side engaging portion 24, it is not necessary to perform machining on the portion of the output-side engaging portion 24 that engages with the output-side engaged portion 38. For example, the output member 9 can be manufactured by forging a metal material to form its outer shape, and then performing finishing processes such as grinding as needed. This reduces the manufacturing cost of the output member 9. However, the output member 9 can also be manufactured by machining a metal material, including cutting. Furthermore, the flat surface portion 25 and the partially cylindrical surface portion 26 can be connected by chamfered portions such as C-chamfers and R-chamfers.

[0122] The output-side engaging portion 24 is located radially inward of the two input-side engaging portions 18, and is positioned between the output-side engaged portions 38 of the two engaging elements 10.

[0123] In this example, the output member 9 has, in addition to the output-side engaging portion 24, an output shaft portion 27, an output flange portion 28, and a small-diameter shaft portion 29.

[0124] The output shaft portion 27 is formed by the input shaft of the output mechanism, or, as in this example, if the output member 9 is configured as a separate component from the input shaft, it can be fixed coaxially to the input shaft, etc. In this example, the output shaft portion 27 has a stepped cylindrical shape.

[0125] The output flange portion 28 protrudes radially outward from the outer peripheral surface of one axial end of the output shaft portion 27 over its entire circumference. The output flange portion 28 is an element for attaching the output member 9 to the pressed member 7 or the structural element so that it can rotate and cannot be displaced in the axial direction.

[0126] The output-side engaging portion 24 protrudes from the center of the end face on one axial side of the output shaft portion 27 toward the axial side.

[0127] The small-diameter shaft portion 29 has a cylindrical shape and protrudes from the center of the axial end face of the output-side engaging portion 24 toward the axial direction toward the axial direction. The small-diameter shaft portion 29 is an element that ensures the coaxiality of the output member 9 with respect to the input member 8.

[0128] In this example, the output member 9 is rotatably supported radially inward of the housing element 12 of the pressed member 7 by a radial rolling bearing 30. The outer ring 31 of the radial rolling bearing 30 is fitted snugly into the small-diameter cylindrical surface portion 14 of the housing element 12 and is axially clamped between one axial side surface of the inward flange portion 16 and a retaining ring 32a that is locked to one axial end of the small-diameter cylindrical surface portion 14. The inner ring 33 of the radial rolling bearing 30 is fitted snugly onto one axial end of the output shaft portion 27 and is axially clamped between the other axial side surface of the output flange portion 28 and a retaining ring 32b that is locked to the outer circumferential surface of the axial intermediate portion of the output shaft portion 27.

[0129] The radial rolling bearing 30 is composed of a ball bearing using balls as rolling elements 34. However, the radial rolling bearing for supporting the output member 9 can also be composed of a tapered roller bearing using tapered rollers as rolling elements or a roller bearing using cylindrical rollers.

[0130] Furthermore, the small-diameter shaft portion 29 of the output member 9 is supported by a sliding bearing (sleeve) 35 inside the input member 8, allowing for free relative rotation with respect to the input member 8.

[0131] (Engineer) In this example, the engager 10 is composed of two engagers 10. Each engager 10 has the function of an engager 10.

[0132] The engaging element 10 can be manufactured by any method. For example, the engaging element 10 can be manufactured by stamping, sintering, forging, casting, cutting, or a combination thereof. In this example, in order to reduce the manufacturing cost of the engaging element 10, the engaging element 10 is a press-formed product of a metal sheet manufactured by stamping.

[0133] In this example, since the engaging element 10 is composed of two engaging elements 10, each engaging element 10 has a substantially semicircular end face shape when viewed from the axial direction and has a shape that is symmetrical with respect to the width direction.

[0134] In this example, the engaging element 10 has, as an optional component, a convex curved surface portion 39, 40 on at least one of the parts of the input-side engaged portion 37 that engages with the input-side engaging portion 18, and the output-side engaged portion 38 that engages with the output-side engaging portion 24. This makes it possible to bring the convex curved surface portion 39 of the input-side engaged portion 37 into contact with the radially inner surface 19 of the input-side engaged portion 18, or to bring the convex curved surface portion 40 of the output-side engaged portion 38 into contact with the flat surface portion 25 of the output-side engaging portion 24, or both, when the reverse input blocking clutch 5 is operated.

[0135] When a convex curved surface portion 39 is arranged on the part of the input-side engaged portion 37 that engages with the input-side engaged portion 18, each input-side engaged portion 37 has two parts that engage with the input-side engaged portion 18, so the convex curved surface portion 39 is provided at two locations on each input-side engaged portion 37.

[0136] When a convex curved surface portion 40 is arranged on the portion of the output-side engaged portion 38 that engages with the output-side engaged portion 24, the convex curved surface portion 40 is provided at two locations on each output-side engaged portion 38, since each output-side engaged portion 38 has two portions that engage with the output-side engaged portion 24.

[0137] In this example, the engaging element 10 has a convex curved surface portion 39 in the portion of the input-side engaged portion 37 that engages with the input-side engaging portion 18, and a convex curved surface portion 40 in the portion of the output-side engaged portion 38 that engages with the output-side engaging portion 24. Therefore, the contact pressure at the contact points between the input member 8 and the output member 9 and the engaging element 10 can be kept low.

[0138] In this example, the pressing surface 36 is composed of two pressing surfaces 36 located at two positions on the radially outer surface of the engaging element 10 that are spaced apart from each other in the circumferential direction. Each pressing surface 36 is composed of a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the surface to be pressed 11.

[0139] Of the radially outer surface of the engaging element 10, the portion that is circumferentially away from the two pressing surfaces 36 is located radially inward from a virtual circle that is centered on the central axis of the input member 8 and tangent to the two pressing surfaces 36, when viewed from the axial direction. In other words, when the two pressing surfaces 36 are in contact with the surface to be pressed 11, the portion that is circumferentially away from the two pressing surfaces 36 does not come into contact with the surface to be pressed 11.

[0140] In this example, the input-side engaged portion 37 is formed by a through hole provided in the radially intermediate portion of the widthwise center of the engaging element 10. Although not limited to this, the through hole constituting the input-side engaged portion 37 has a substantially arc-shaped opening when viewed from the axial direction and penetrates the radially intermediate portion of the widthwise center of the engaging element 10 in the axial direction.

[0141] The convex curved surface portion 39 is provided on the radially inner surface 41 of the inner surface of the input-side engaged portion 37, which faces radially outward, in the portion that engages with the input-side engaged portion 18, specifically the portion that engages with the radially inner surface 19, so as to be convex toward the input-side engaged portion 18. The convex curved surface portion 39 is provided at two locations on the radially inner surface 41: the portion that engages with the input-side engaged portion 18 when the input member 8 rotates to one side relative to the engaged element 10, and the portion that engages with the input-side engaged portion 18 when the input member 8 rotates to the other side relative to the engaged element 10.

[0142] Specifically, the radial inner surface 41 of the input-side engaged portion 37 is provided with a convex portion 42 that protrudes radially outward from the adjacent portions on both sides in the second direction, and convex curved portions 39 are provided at two locations in the second direction of the convex portion 42.

[0143] In this example, the convex curved surface portion 39 is provided at both ends of the convex portion 42 in the second direction. The convex portion 42 also has a connecting surface portion 44 in the second direction intermediate portion between the two convex curved surface portions 39, which connects the two convex curved surface portions 39 and is formed by a flat surface perpendicular to the first direction.

[0144] The shape and radius of curvature of the convex curved surface portion 39 as viewed from the axial direction are not particularly limited, as long as it is possible to prevent the contact pressure at the contact point with the input-side engaging portion 18 from becoming excessive. For example, the shape of the convex curved surface portion 39 as viewed from the axial direction can be a roughly circular arc, a roughly elliptical arc, etc. The shape and radius of curvature of the convex curved surface portion 39 as viewed from the axial direction can be determined by experiment, simulation, etc.

[0145] In this example, the radially outer surface 43 of the inner surface of the input-side engaged portion 37, which faces radially inward, is composed of a curved surface having a substantially arc-shaped contour or a composite surface having a substantially V-shaped contour when viewed from the axial direction. The circumferential surface 45 connecting the radially inner surface 41 and the radially outer surface 43 is composed of a partially cylindrical concave curved surface.

[0146] In this example, the output-side engaged portion 38 is provided at the center of the width direction of the radially inner surface of the engaging element 10, so as to protrude radially inward from the portions adjacent to it on both sides in the width direction.

[0147] The convex curved portion 40 is provided at two locations within the output-side engaged portion 38, specifically the portion that engages with the output-side engaged portion 24 when the output member 9 rotates to one side relative to the engager 10, and the portion that engages with the output-side engaged portion 24 when the output member 9 rotates to the other side relative to the engager 10, so as to be convex toward the output-side engaged portion 24.

[0148] In this example, the convex curved surface portion 40 is provided at both ends of the output-side engaged portion 38 in the width direction (second direction). The output-side engaged portion 38 also has a connecting surface portion 46 in the width direction intermediate between the two convex curved surface portions 40, which connects the two convex curved surface portions 40 and is formed by a flat surface perpendicular to the radial direction.

[0149] The shape and radius of curvature of the convex curved surface portion 40 as viewed from the axial direction are not particularly limited, as long as it is possible to prevent the contact pressure at the contact point with the output side engaging portion 24 from becoming excessive. For example, the shape of the convex curved surface portion 40 as viewed from the axial direction can be a roughly circular arc, a roughly elliptical arc, etc. The shape and radius of curvature of the convex curved surface portion 40 as viewed from the axial direction can be determined by experiment, simulation, etc.

[0150] In this example, the engaging element 10 is provided with convex curved surfaces 39 and 40 to reduce the contact pressure at the contact points between the input member 8 and the output member 9 and the engaging element 10. Therefore, compared to the case where the convex curved surfaces are provided by machining the contact points of the input member 8 and the output member 9 with the engaging element 10, manufacturing costs can be reduced.

[0151] Furthermore, in this example, the engaging element 10, which has convex curved surfaces 39 and 40 at the contact points with the input member 8 and the output member to reduce contact pressure, is manufactured by press stamping. This also helps to reduce manufacturing costs.

[0152] In this example, the radially inner surface 19 of the input-side engaging portion 18 is brought into contact with one of the two convex curved surfaces 39 provided on the input-side engaged portion 37.

[0153] From this state, as the input member 8 rotates further, the radially inner surface 19 of the input-side engaging portion 18 presses one of the convex curved portions 39 radially inward, causing the engaging element 10 to move away from the pressed surface 11. That is, the two engaging elements 10 move radially inward, towards each other, based on their engagement with the input member 8, causing the radially inner surfaces of the two engaging elements 10 to approach each other, and the output-side engaging portion 24 of the output member 9 is clamped from both radial sides by the output-side engaged portions 38 of the two engaging elements 10.

[0154] When rotational torque is input in reverse to the output member 9, the two engaging elements 10 move toward the pressed surface 11, regardless of the rotation direction of the output member 9. Specifically, as shown in Figure 5, the output-side engaging portion 24 rotates in the direction of rotation of the output member 9 (clockwise in the example of Figure 5) inside the output-side engaged portions 38 of the two engaging elements 10. The output-side engaging portion 24 then presses the output-side engaged portions 38 radially outward. In this example, the flat surface portion 25 of the outer circumferential surface of the output-side engaging portion 24 presses one of the two convex curved surfaces 40 provided on the output-side engaged portion 38 radially outward. As a result, the two engaging elements 10 move toward the pressed surface 11.

[0155] In other words, the two engaging elements 10 move radially outward, away from each other, based on their engagement with the output member 9, so that the pressing surfaces 36 of the two engaging elements 10 come into contact with the pressed surface 11 and frictionally engage with the pressed surface 11.

[0156] (Biasing member and holding member) In the motor 1 with reverse input blocking clutch of this example, the reverse input blocking clutch 5 further comprises a biasing member 47 and a holding member 48 as optional components.

[0157] The biasing member 47 elastically biases the engaging element 10 toward the pressed surface 11. The biasing member 47 can be made of a spring such as a leaf spring, coil spring, or disc spring, or an elastic material such as rubber, elastomer, or synthetic resin. The number of biasing members 47 is not particularly limited and is appropriately determined according to the number of engaging elements 10.

[0158] In this example, the biasing member 47 is composed of two biasing members 47 positioned at two locations in the width direction between the radially inner surfaces of the two engaging elements 10, and each biasing member 47 is composed of a compression coil spring. Each biasing member 47 is fitted and held in the holding hole 49 of the holding member 48, thereby preventing it from falling out from the portion between the two engaging elements 10.

[0159] The two biasing members 47 elastically bias the two engaging elements 10 toward the pressed surface 11 by the force that attempts to restore them elastically. As a result, in a neutral state where no torque is applied to either the input member 8 or the output member 9, the pressing surfaces 36 of the two engaging elements 10 come into contact with the pressed surface 11.

[0160] The retaining member 48 comprises a first spacer portion 50 and a second spacer portion 51 arranged spaced apart in the axial direction, and two connecting portions 52 arranged on both sides of the first spacer portion 50 and the second spacer portion 51 with respect to a second direction, each connecting the first spacer portion 50 and the second spacer portion 51, and each having a retaining hole 49 extending in the first direction.

[0161] The retaining member 48 is attached to the output member 9 with the engaging element 10 positioned between the first spacer portion 50 and the second spacer portion 51 in the axial direction, thereby restricting the axial movement of the engaging element 10 relative to the output member 9. Specifically, the retaining ring 53, which is locked to the small-diameter shaft portion 29 of the output member 9, restricts the movement of the retaining member 48 to one side in the axial direction, and the other side of the second spacer portion 51 is brought into contact with or close to the end face of the output shaft portion 27 on one side in the axial direction, thereby restricting the movement of the retaining member 48 to the other side in the axial direction.

[0162] [Steering Device] As described above, the motor 1 with reverse input blocking clutch in this example can be suitably applied to the drive devices of various mechanical devices such as the steering device 2. When the motor 1 with reverse input blocking clutch is applied to the steering device 2, it may be applied to either the drive motor for the rear wheel steering device or the drive device for the front wheel steering motor.

[0163] The following describes an example of a steering device 2 to which the motor 1 with reverse input blocking clutch of this example is applied, although this example is not limited to this example. The description is based on an example in which the motor 1 with reverse input blocking clutch is applied to a steering device for the rear wheels.

[0164] The steering device 2 comprises a motor 1 with a reverse input blocking clutch and a linear motion mechanism 55.

[0165] In the steering device 2, a motor with a reverse input blocking clutch 1 equipped with a reverse input blocking clutch 5 is provided as the drive motor, in order to enable the application of a steering angle to the left and right steering wheels 54 in accordance with the amount of steering wheel operation, and to prevent the transmission of shock torque due to the steering wheels 54 riding up onto a curb, vibrations from the road surface, etc., to the motor 3, while enabling the application of a steering angle to the left and right steering wheels 54 in accordance with the amount of steering wheel operation, etc.

[0166] The linear motion mechanism 55 has a rod 56 that converts the rotational motion of the output member 9 into linear motion in the axial direction of the rod 56. The rod 56 is supported so as to be able to move linearly in the axial direction, with its axial direction facing the width direction of the vehicle body, and is connected to the steering wheel 54 so as to change the orientation of the steering wheel 54 in accordance with the linear motion.

[0167] The base ends of tie rods 57 are connected to the axial ends of rod 56 via spherical joints (not shown), and the base ends of knuckle arms 58 are pivotably supported at the tips of each tie rod 57. The knuckles constituting the suspension system are supported at the tips of each knuckle arm 58 so as to be able to pivot around a kingpin. Each steering wheel 54 is rotatably supported relative to the knuckle via a hub unit bearing.

[0168] The linear motion mechanism 55 can employ any structure as long as it can convert the rotational motion of the output member 9 into linear motion in the axial direction of the rod 56.

[0169] For example, the linear motion mechanism 55 can be configured to include a sliding screw type or a ball type lead screw mechanism 59. When the linear motion mechanism 55 is configured to include a sliding screw type lead screw mechanism, the lead screw mechanism 59 is configured by directly screwing (sliding into contact) a female screw groove formed on the inner circumferential surface of a nut that is rotationally driven by an output member 9 with a male screw groove formed on the outer circumferential surface of a rod 56. When the linear motion mechanism 55 is configured to include a ball type lead screw mechanism, the lead screw mechanism 59 can be configured by arranging a plurality of balls 61 so as to be able to roll between a female ball screw groove formed on the inner circumferential surface of a ball nut 60 that is rotationally driven by an output member 9 and a male ball screw groove formed on the outer circumferential surface of a rod 56.

[0170] When the linear motion mechanism 55 is configured to include a lead screw mechanism 59, it is preferable to use a ball-type lead screw mechanism as the lead screw mechanism 59, as it has higher torque transmission efficiency and makes it easier to miniaturize the motor 3 compared to a sliding screw type lead screw mechanism.

[0171] As in this example, when the linear motion mechanism 55 is configured to include a ball-type lead screw mechanism 59, the lead screw mechanism 59 comprises a rod 56, a ball nut 60, and a plurality of balls 61.

[0172] The rod 56 has a helical male ball screw groove on its outer surface.

[0173] The ball nut 60 has a helical female ball screw groove on its inner circumferential surface and is supported around the rod 56 so that it can only rotate. The ball nut 60 is rotationally driven by the output member 9 of the motor 1 with a reverse input blocking clutch.

[0174] The ball nut 60 is rotationally driven by the output member 9 via the torque transmission mechanism 62. In other words, the steering device 2 can be equipped with a torque transmission mechanism 62 that transmits the rotational motion, or in other words the torque, of the output member 9 of the motor 1 with reverse input blocking clutch to the ball nut 60, which is the torque input part of the linear motion mechanism 55.

[0175] The torque transmission mechanism 62 can be composed of a gear-type reducer, a belt or chain-type reducer, a worm gear reducer, and the like. In this example, the torque transmission mechanism 62 is composed of a gear-type reducer. Therefore, the torque transmission mechanism 62 has a drive gear 63 fitted and fixed to the output shaft portion 27 of the output member 9, an intermediate gear 64 that meshes with the drive gear 63, and a driven gear 65 that is provided around the ball nut 60 and meshes with the intermediate gear 64. In this case, two or more intermediate gears 64 may be provided. Alternatively, the torque transmission mechanism 62 can also be composed of a drive gear 63 provided on the output member 9 of the motor 1 with a reverse input blocking clutch and a driven gear 65 provided on the ball nut 60 that mesh directly.

[0176] In the feed screw mechanism 59, a plurality of balls 61 are arranged to roll freely in a load path consisting of a male ball screw groove of the rod 56 and a female ball screw groove of the ball nut 60.

[0177] The start and end points of the load path are connected by a circulation path provided on the inner circumferential surface of the ball nut 60, or by a circulation component fixed to the ball nut 60.

[0178] When the steering device 2 applies a steering angle to the two steering wheels 54, sensors detect the amount or speed of rotation of the steering wheel of the steering device (not shown), the vehicle speed, and the surrounding conditions. Based on this sensor information, the controller 4 controls the amount and direction of current supplied to the motor 3. As a result, when the input member 8 is rotated, the lock of the reverse input blocking clutch 5 is released, as shown in Figure 4, and the rotation of the input member 8 is transmitted to the output member 9. In the steering device 2, the limiting function of the controller 4 in the motor 1 with a reverse input blocking clutch (control of the reverse input blocking clutch 5), the regulation of the relationship between the input-side angle and the output-side angle in the reverse input blocking clutch 5, or both, effectively prevents or suppresses the generation of abnormal noise when the transmission of rotational torque from the input member 8 to the output member 9 begins.

[0179] The rotation of the output member 9 is transmitted to the ball nut 60 by the torque transmission mechanism 62, and as the ball nut 60 rotates, the rod 56 moves linearly in the axial direction, pushing and pulling the tie rod 57 and applying a steering angle to the steering wheel 54.

[0180] When the steering wheel 54 hits a curb or experiences other impactful loads, or when vibrations from the road surface are transmitted to the steering wheel 54 during off-road driving, a rotational torque is reverse-input from the linear motion mechanism 55 to the output member 9 via the torque transmission mechanism 62. As shown in Figure 5, this locks the output member 9. This prevents the axial linear motion of the rod 56. As a result, even when an impactful load is applied to the steering wheel 54, no steering angle is applied to the steering wheel 54, preventing the vehicle's behavior from becoming unstable.

[0181] 1 Motor with reverse input blocking clutch 2 Steering device 3 Motor 4 Controller 5 Reverse input blocking clutch 6 Motor output shaft 7 Pressed member 8 Input member 9 Output member 10 Engaging element 11 Pressed surface 12 Housing element 13 Large diameter cylindrical surface 14 Small diameter cylindrical surface 15 Connecting surface 16 Inward flange 17 Screw hole 18 Input side engaging part 19 Radial inner surface 20 Radial outer surface 21 Ridge 22 Input shaft 23 Input flange 24 Output side engaging part 25 Flat surface 26 Partial cylindrical surface 27 Output shaft 28 Output flange 29 Small diameter shaft 30 Radial rolling bearing 31 Outer ring 32a, 32b Retaining ring 33 Inner ring 34 Rolling element 35 Sliding bearing 36 Pressing surface 37 Input side engaged portion 38 Output side engaged portion 39 Convex curved surface portion 40 Convex curved surface portion 41 Radially inner surface portion 42 Convex portion 43 Radially outer surface portion 44 Connecting surface portion 45 Circumferential surface portion 46 Connecting surface portion 47 Biasing member 48 Holding member 49 Holding hole 50 First spacer portion 51 Second spacer portion 52 Connecting portion 53 Retaining ring 54 Steering wheel 55 Linear motion mechanism 56 Rod 57 Tie rod 58 Knuckle arm 59 Lead screw mechanism 60 Ball nut 61 Ball 62 Torque transmission mechanism 63 Drive gear 64 Intermediate gear 65 Driven gear 66 Ridge portion

Claims

1. A motor having a motor output shaft, a controller for controlling the rotation of the motor output shaft, and a reverse input blocking clutch, wherein the reverse input blocking clutch comprises: a pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion arranged radially inward from the pressed surface, arranged coaxially with the pressed surface, and rotationally driven by the motor output shaft; an output member having an output-side engaging portion arranged radially inward from the input-side engaging portion, and arranged coaxially with the pressed surface; and an engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to be movable in the radial direction. When rotational torque is input from the motor output shaft to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, thereby engaging the output-side engaged portion with the output-side engaging portion and transmitting the rotational torque input to the input member to the output member. Conversely, when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, thereby frictionally engaging the pressing surface with the pressed surface. A motor with a reverse input cutoff clutch having a limiting function, wherein when the transmission of rotational torque from the input member to the output member begins based on the input torque being input from the motor output shaft to the input member, the controller controls the angular acceleration of the motor output shaft so that the angular acceleration of the input member is less than or equal to a predetermined limit angular acceleration, or controls the angular acceleration of the motor output shaft so that the angular velocity of the input member is less than or equal to a predetermined limit angular velocity, until the input member rotates by a limit angle that prevents or suppresses the generation of a collision sound due to the input side engaging portion colliding with the input side engaged portion, the generation of a collision sound due to the output side engaged portion colliding with the output side engaging portion, or both.

2. The limiting angle is the sum of the angle from the state in which the pressing surface is in contact with the pressed surface and the input side engaging portion is positioned at the circumferential center inside the input side engaged portion, until the input side engaging portion engages with the input side engaged portion as the input member rotates to one side or the other, and the angle from the state in which the pressing surface is in contact with the pressed surface and the output side engaging portion engages with the output side engaged portion as the output member rotates to one side, and the angle from the state in which the pressing surface is in contact with the pressed surface and the output side engaging portion engages with the output side engaged portion as the output member rotates to the other side, until the output side engaging portion engages with the output side engaged portion as the output member rotates to one side or the other, plus a predetermined margin angle, as described in claim 1.

3. The limiting angle is the sum of the angle from the state in which the pressing surface is in contact with the pressed surface and the input side engaging portion is engaged with the input side engaged portion as the input member rotates to one side until the input side engaging portion is engaged with the input side engaged portion as the input member rotates to the other side, and the angle from the state in which the pressing surface is in contact with the pressed surface and the output side engaging portion is engaged with the output side engaged portion as the output member rotates to the other side until the output side engaging portion is engaged with the output side engaged portion as the output member rotates to the one side, plus a predetermined margin angle, as described in claim 1, the motor with reverse input cutoff clutch.

4. A motor with a reverse input blocking clutch according to any one of claims 1 to 3, wherein, in a state in which the pressing surface is in contact with the pressed surface, the angle from which the output side engaging portion engages with the output side engaged portion as the output member rotates to one side is the same as the angle from which the output side engaging portion engages with the output side engaged portion as the output member rotates to the other side, the angle from which the output side engaging portion engages with the output side engaged portion as the output member rotates to one side or the other side is smaller than the angle from which the input side engaging portion engages with the input side engaged portion as the input member rotates to one side or the other side, starting from a state in which the pressing surface is in contact with the pressed surface and the input side engaging portion is positioned at the circumferential center inside the input side engaged portion.

5. The motor with reverse input blocking clutch according to any one of claims 1 to 4, wherein the controller does not perform the limiting function if the angular acceleration or angular velocity of the input member calculated based on an external input is greater than a predetermined threshold.

6. The motor with reverse input blocking clutch according to any one of claims 1 to 5, wherein the engaging element has a convex curved surface portion on at least one of the portions of the input-side engaged portion that engages with the input-side engaging portion and the portion of the output-side engaged portion that engages with the output-side engaging portion.

7. A steering device comprising: a motor with a reverse input blocking clutch having an output member; and a linear motion mechanism having a rod connected to the steering wheel, which is supported to enable linear motion in the axial direction of the motor and changes the direction of the steering wheel according to the linear motion, and which converts the rotational motion of the output member into linear motion in the axial direction of the rod, wherein the motor with a reverse input blocking clutch is configured as a motor with a reverse input blocking clutch according to any one of claims 1 to 6.

8. The steering device according to claim 7, wherein the steering wheel is a rear wheel.

9. A pressed member having a pressed surface on its inner circumferential surface; an input member having an input-side engaging portion arranged radially inward from the pressed surface and arranged coaxially with the pressed surface; an output member having an output-side engaging portion arranged radially inward from the input-side engaging portion and arranged coaxially with the pressed surface; and an engaging element having a pressing surface facing the pressed surface, an input-side engaged portion that can engage with the input-side engaging portion, and an output-side engaged portion that can engage with the output-side engaging portion, and arranged to be movable in the radial direction. A control method for a reverse input blocking clutch, wherein when rotational torque is input to the input member, the engaging element moves radially away from the pressed surface based on the input-side engaging portion engaging with the input-side engaged portion, and transmits the rotational torque input to the input member to the output member by engaging the output-side engaged portion with the output-side engaging portion; and when rotational torque is input in reverse to the output member, the engaging element presses the pressing surface against the pressed surface based on the output-side engaging portion engaging with the output-side engaged portion, thereby frictionally engaging the pressing surface with the pressed surface. A control method for a reverse input cutoff clutch, wherein, when the input member begins to rotate in response to the input of rotational torque, the angular acceleration of the input member is restricted to a predetermined limit angular acceleration, or the angular velocity of the input member is restricted to a predetermined limit angular velocity, until the input member rotates to a limit angle that prevents or suppresses the generation of a collision sound due to the input-side engaging portion colliding with the input-side engaged portion, the generation of a collision sound due to the output-side engaged portion colliding with the output-side engaging portion, or both.

10. The control method for a reverse input shutoff clutch according to claim 9, wherein the limiting angle is the sum of the angle from a state in which the pressing surface is in contact with the pressed surface and the input side engaging portion is positioned at the circumferential center inside the input side engaged portion, until the input side engaging portion engages with the input side engaged portion as the input member rotates to one side or the other, and the angle from a state in which the pressing surface is in contact with the pressed surface, where the angle from the time the output side engaging portion engages with the output side engaged portion as the output member rotates to one side and the angle from the time the output side engaging portion engages with the output side engaged portion as the output member rotates to the other side is the same, until the output side engaging portion engages with the output side engaged portion as the output member rotates to one side or the other, plus a predetermined margin angle.

11. The control method for a reverse input shutoff clutch according to claim 9, wherein the limiting angle is the sum of the angle from the state in which the pressing surface is in contact with the pressed surface and the input side engaging portion is in contact with the input side engaged portion as the input member rotates to one side until the input side engaging portion is in contact with the input side engaged portion as the input member is rotated to the other side, and the angle from the state in which the pressing surface is in contact with the pressed surface and the output side engaging portion is in contact with the output side engaged portion as the output member rotates to the other side until the output side engaging portion is in contact with the output side engaged portion as the output member is rotated to the one side, plus a predetermined margin angle.

Images