Suspension device and control method for suspension device

Abstract

[Problem] To realize a structure, with which vehicle height can be smoothly adjusted. [Solution] A controller 51 has a function of controlling an electric motor 3 such that if the vehicle height is to be adjusted, in a case in which the direction of a rotational torque reversely input into a clutch output member 11 is the same as the direction in which a clutch input member 10 is rotated, and the rotational speed of the clutch input member 10 is in a rotational speed range equal to or less than a prescribed threshold value at which a jerking phenomenon is likely to occur, the electric motor can quickly pass through the rotational speed range thereof.

Description

Suspension system and method for controlling suspension system

[0001] The present disclosure relates to a suspension system for supporting wheels on a vehicle body and a control method thereof.

[0002] In large vehicles such as buses, it is preferable to lower the vehicle height when the vehicle is stopped to make it easier for passengers to get on and off. In addition, in vehicles with low vehicle heights and a narrow gap between the bottom of the vehicle body and the road surface, such as sports cars, it is preferable to raise the vehicle height to prevent the bottom of the vehicle body from contacting the step when going over a sidewalk step at extremely low speeds, and to make it easier for passengers to get on and off. For this reason, the suspension systems of these vehicles are sometimes equipped with height adjustment devices to adjust the vehicle height.

[0003] Japanese Patent Application Laid-Open Publication No. 2021-037868 discloses a vehicle height adjustment device installed on a vehicle suspension system. This conventional vehicle height adjustment device includes a sleeve that is extrapolated onto a shock absorber shell and has a male threaded portion, a housing that rotatably supports a top member that has a female threaded portion that screws into the male threaded portion, and a drive motor that rotates the top member. In the conventional vehicle height adjustment device, the drive motor rotates the top member, causing the housing to rise and fall relative to the sleeve, and the spring bearing provided on the upper surface of the housing to rise and fall, thereby adjusting the vehicle height.

[0004] This vehicle height adjusting device further includes a reverse input blocking clutch interposed between the drive motor and the bridge member, which transmits the forward and reverse rotation of the drive motor to the bridge member and prevents the reverse rotation input from the bridge member from being transmitted to the drive motor. Therefore, with this vehicle height adjusting device, even if the drive motor is de-energized after adjusting the vehicle height, the reverse input blocking clutch prevents the bridge member from rotating due to the weight of the vehicle body and occupants, and the vehicle height is maintained.

[0005] Japanese Patent Application Laid-Open No. 2021-037868

[0006] In the conventional vehicle height adjustment device described in JP 2021-037868 A, there is a possibility that the behavior may become unstable when adjusting the vehicle height.

[0007] In other words, before the vehicle height is adjusted, a force is applied from the wheel side to the output portion of the reverse input cut-off clutch, tending to rotate the output portion, based on the weight of the vehicle body and occupants, the elasticity of the spring, etc.

[0008] When the direction of the force applied to the clutch output from the wheel matches the direction in which the drive motor rotates the clutch input to adjust the vehicle height to the desired height, if the rotation speed of the clutch output is greater than the rotation speed of the clutch input, the rotation of the case and the rotation of the over member are also locked. However, even in this state, torque is being input to the input, so the clutch is unlocked the next moment and the over member rotates.

[0009] In other words, when the direction of the force applied to the clutch output part from the wheel side based on the weight of the vehicle body and occupants, the elasticity of the spring, etc., coincides with the direction in which the drive motor rotates the clutch input part to adjust the vehicle height to the desired height, the clutch may repeatedly alternate between an unlocked state in which torque can be transmitted between the input part and the output part and a locked state in which torque cannot be transmitted between the input part and the output part in a short period of time, causing a jerking phenomenon in which the input part and the output part intermittently rotate in a predetermined direction. When this jerking phenomenon occurs, the movement of the bridge member becomes unstable, making it impossible to perform smooth vehicle height adjustment.

[0010] An object of the present disclosure is to provide a suspension system and a control method for a suspension system that can smoothly adjust the vehicle height.

[0011] The inventors of the present disclosure conducted extensive research into the conditions under which jerking occurs in a reverse input disconnect clutch that constitutes a suspension system, and as a result, discovered that jerking occurs when the rotation speed of a clutch input member rotating in a predetermined direction becomes lower than a predetermined threshold value while torque in a predetermined direction is reversely input to a clutch output member. A suspension system according to one aspect of the present disclosure and a control method for a suspension system according to one aspect of the present disclosure were completed based on this discovery.

[0012] A suspension system according to one aspect of the present disclosure includes a spring, a vehicle height adjustment mechanism, and a controller.

[0013] The spring is provided so as to span between the vehicle body and a member supporting the wheel.

[0014] The vehicle height adjustment mechanism includes an electric motor, a reverse input cutoff clutch, and a spring adjustment mechanism.

[0015] The electric motor has a motor output shaft.

[0016] The reverse input blocking clutch has a clutch input member that is rotationally driven based on the rotation of the motor output shaft, and a clutch output member. When rotational torque is input to the clutch input member, the clutch transmits the rotational torque input to the clutch input member to the clutch output member, whereas when rotational torque is input in reverse to the clutch output member, the clutch does not transmit the rotational torque input in reverse to the clutch input member.

[0017] The spring adjustment mechanism moves or rotates the spring in the vertical direction in response to rotation of the clutch output member.

[0018] The vehicle height adjustment mechanism adjusts the vehicle height, which is the height of the vehicle body from the wheel contact surface, by moving or rotating the spring in an up and down direction using the spring adjustment mechanism based on the rotational driving of the motor output shaft.

[0019] The controller controls the electric motor.

[0020] In particular, in a suspension device according to one aspect of the present disclosure, the controller has at least one of the following functions: a first function, when starting control to adjust the vehicle height in a direction in which the clutch input member rotates in the same direction as the direction of the rotational torque being reversely input to the clutch output member from a state in which the reverse input cut-off clutch is locked due to a rotational torque being reversely input to the clutch output member, and, when the rotational speed of the clutch input member becomes greater than a predetermined first threshold value, switching the rotational acceleration of the motor output shaft to a second rotational acceleration smaller than the first rotational acceleration; and a second function, when the control to adjust the vehicle height is terminated and the rotational speed of the clutch input member becomes equal to or less than a predetermined second threshold value, setting the target value of the rotational speed of the clutch input member to 0 if the direction of the rotational torque being reversely input to the clutch output member is the same as the rotational direction of the clutch input member.

[0021] In a suspension system according to one aspect of the present disclosure, the controller can have the first function and can be configured to control the output shaft of the motor by speed control or position control.

[0022] Alternatively, in a suspension device of one aspect of the present disclosure, the controller can have the first function, and can be configured to control the motor output shaft by torque control when the rotation speed of the clutch input member is in a range from the start of the motor output shaft to the predetermined first threshold value, and to control the motor output shaft by speed control or position control after the rotation speed of the clutch input member becomes greater than the predetermined first threshold value.

[0023] In a suspension device according to one aspect of the present disclosure, the reverse input cutoff clutch can comprise: a pressed member having a pressed surface on its inner circumferential surface; the clutch input member having an input side engaging portion arranged radially inward of the pressed surface and arranged coaxially with the pressed surface; the clutch output member having an output side engaging portion arranged radially inward of the input side engaging portion on the radial inside of the pressed surface and arranged coaxially with the pressed surface; and an engager having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be radially movable.

[0024] When rotational torque is input to the clutch input member, the engaging element moves radially inward based on the engagement of the input side engaging portion with the input side engaged portion, and transmits the rotational torque input to the clutch input member to the clutch output member by engaging the output side engaged portion with the output side engaging portion, whereas when rotational torque is input in the reverse direction to the clutch output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, causing the pressing surface to frictionally engage with the pressed surface.

[0025] In the suspension device according to one aspect of the present disclosure, the pressing surface can be configured by two pressing surfaces.

[0026] In this case, the reverse input cutoff clutch can be configured such that, in a state in which the two pressing surfaces are pressed against the pressed surface as the clutch output member rotates in a predetermined direction, and the input side engaging portion and the input side engaged portion are engaged as the clutch input member rotates in a direction opposite to the predetermined direction, the distance between the contact portion between the input side engaging portion and the input side engaged portion and the center of rotation of the clutch input member in a second direction perpendicular to both a first direction which is the radial direction of the engager and the center of rotation of the clutch input member is greater than the distance between the contact portion between the output side engaging portion and the output side engaged portion and the center of rotation of the clutch output member in the second direction, When a rotational torque is input in reverse to the clutch output member and the two pressing surfaces are in contact with the pressed surface, the contact portion between the output side engaging portion and the output side engaged portion can be configured to be located closer to the center of rotation of the clutch output member in the first direction than an imaginary line connecting the abutment portion between one of the two pressing surfaces and the pressed surface and the center of rotation of the clutch output member.

[0027] In the suspension device according to one aspect of the present disclosure, the reverse input cutoff clutch may include a biasing member that elastically biases the engagement element in a direction that brings the pressing surface closer to the pressed surface.

[0028] In the suspension device according to one aspect of the present disclosure, the engagement element can be configured by two engagement elements, and the input side engagement portion can be configured by two input side engagement portions.

[0029] In a suspension system of one aspect of the present disclosure, the controller can have the first function, and the suspension system can have a speed sensor for measuring the rotation speed of the clutch input member, a stroke sensor for measuring the vehicle height, and / or an angle sensor for measuring the rotation angle of the clutch input member.

[0030] A suspension device according to one aspect of the present disclosure may include a cylinder supported on the wheel, a piston supported on the vehicle body and fitted into the cylinder, and a damper arranged in parallel with the spring between the vehicle body and the wheel.

[0031] The suspension device of one aspect of the present disclosure can include a spring seat that is supported to allow relative movement in the vertical direction but not rotation relative to the cylinder. In this case, the spring can be configured as a coil spring that is elastically sandwiched between the vehicle body and the spring seat, and the spring adjustment mechanism can be configured to convert rotational movement of the clutch output member into vertical movement of the spring seat relative to the cylinder.

[0032] The spring adjustment mechanism may include a nut having an outer diameter side ball screw groove on its inner peripheral surface and being rotationally driven based on the rotation of the clutch output member, and a plurality of balls disposed to be able to roll between the inner diameter side ball screw groove and the outer diameter side ball screw groove provided on the outer peripheral surface of the cylinder or the outer peripheral surface of a member supported and fixed to the cylinder. In this case, the nut may be supported to be able to move up and down and rotate relative to the cylinder, and to be able to move up and down integrally with the spring seat.

[0033] In the suspension device according to one aspect of the present disclosure, the spring may be a torsion bar, and in this case, the spring adjustment mechanism may be configured to rotate the torsion bar in conjunction with rotation of the clutch output member.

[0034] A suspension system that is the subject of a suspension system control method according to one embodiment of the present disclosure comprises: a spring that is arranged to span between a vehicle body and a member that supports a wheel; an electric motor having a motor output shaft; a clutch input member that is rotationally driven based on the rotation of the motor output shaft; and a reverse input cut-off clutch that has a clutch output member and that, when rotational torque is input to the clutch input member, transmits the rotational torque input to the clutch input member to the clutch output member, but, when rotational torque is reversely input to the clutch output member, does not transmit the rotational torque reversely input to the clutch output member to the clutch input member; and a vehicle height adjustment mechanism that includes a spring adjustment mechanism that moves or rotates the spring in an up and down direction in accordance with the rotation of the clutch output member, and that adjusts the height of the vehicle body from the wheel contact surface by moving or rotating the spring in an up and down direction using the spring adjustment mechanism based on the rotational driving of the motor output shaft.

[0035] In one aspect of the suspension control method disclosed herein, when starting control to adjust the vehicle height in a direction that rotates the clutch input member in the same direction as the direction of the rotational torque being reversely input to the clutch output member from a state in which the reverse input cut-off clutch is locked due to a rotational torque being reversely input to the clutch output member, the motor output shaft is started at a first rotational acceleration, and when the rotational speed of the clutch input member becomes greater than a predetermined first threshold value, the rotational acceleration of the motor output shaft is switched to a second rotational acceleration that is smaller than the first rotational acceleration.

[0036] In this case, the output shaft of the motor can be controlled by speed control or position control.

[0037] Alternatively, the motor output shaft can be controlled by torque control when the rotation speed of the clutch input member is within a range from the start of the motor output shaft to the predetermined first threshold, and after the rotation speed of the clutch input member becomes greater than the predetermined first threshold, the motor output shaft can be controlled by speed control or position control.

[0038] Alternatively, in a suspension control method according to one aspect of the present disclosure, at the end stage of the control for adjusting the vehicle height when the rotational speed of the clutch input member is equal to or less than a predetermined second threshold, if the direction of the rotational torque being reversely input to the clutch output member is the same as the rotational direction of the clutch input member, the target value of the rotational speed of the clutch input member is set to 0.

[0039] According to the suspension device of one aspect of the present disclosure and the control method for the suspension device of one aspect of the present disclosure, vehicle height adjustment can be performed smoothly.

[0040] FIG. 1 is a schematic cross-sectional view showing a suspension system according to a first embodiment of the present disclosure. FIGS. 2A and 2B are schematic views of the suspension system according to the first embodiment, with FIG. 2A showing the suspension system in a raised state and FIG. 2B showing the suspension system in a lowered state. FIG. 3 is a cross-sectional view showing the reverse input disconnection clutch removed from the suspension system according to the first embodiment. FIG. 4 is a cross-sectional view taken along the line X-X in FIG. 3. FIG. 5 is a view similar to FIG. 4, showing a state in which torque input to the clutch input member is transmitted to the clutch output member. FIG. 6 is a view similar to FIG. 4, showing a state in which torque is reversely input to the clutch output member. FIGS. 7A to 7C are schematic views illustrating the effect of restricting the shapes of the input-side engaging portion and the output-side engaging portion. FIGS. 8A to 8C are schematic views illustrating the mechanism by which jerking occurs. FIG. 9 is a flowchart illustrating a control operation for adjusting the vehicle height using the suspension system according to the first embodiment. Fig. 10 is a diagram showing a relationship between the rotation speed of the motor output shaft and time when adjusting the vehicle height. Fig. 11 is a diagram showing a suspension system according to a second example of an embodiment of the present disclosure. Fig. 12 is a flowchart showing a control operation for adjusting the vehicle height using the suspension system according to the second example.

[0041] First Example A first example of an embodiment of the present disclosure will be described with reference to FIGS. 1 to 10. FIG.

[0042] In the following description, the up-down direction, the front-rear direction, and the width direction (left-right direction) refer to the up-down direction, the front-rear direction, and the width direction (left-right direction) of the vehicle when the suspension device 1 is attached to the vehicle.

[0043] (Overall Description of Suspension Device) The suspension device 1 is configured to press the outer peripheral surface (tread) of the tire that constitutes the wheel W against the road surface using the elastic force of the spring 2, while absorbing vibrations and shocks transmitted from the road surface to the vehicle body B via the wheel W. The suspension device 1 of one aspect of the present disclosure has a function of adjusting the height (height of the lowest part) of the vehicle body B from the contact surface of the outer peripheral surface of the tire that constitutes the wheel W, i.e., the vehicle height (minimum ground clearance).

[0044] The suspension system 1 includes a spring 2 , a vehicle height adjustment mechanism 4 , and a controller 51 .

[0045] The spring 2 is arranged to span between the vehicle body B and the member supporting the wheel W, and generates elastic force to press the outer surface of the tire that constitutes the wheel W against the road surface, and when vibrations or impacts are applied to the wheel W from the road surface, it has the function of absorbing the vibrations or impacts by elastically deforming.

[0046] There is no particular limitation on the type of spring 2 as long as it can perform its function. Specifically, the spring 2 can be a coil spring that is made by winding a metal wire in a spiral shape and generates elastic force in its axial direction, or a torsion bar that is made in a rod shape and generates elastic force in a torsional direction.

[0047] In this example, the spring 2 is a coil spring. The spring 2 is provided between the vehicle body B and a member supporting the wheel W, such as an axle, with its central axis oriented substantially vertically. The spring 2 is elastically sandwiched between a top mount 20 supported and fixed to the vehicle body B and a spring seat 21 supported around the cylinder 13 of the damper 12. That is, the vehicle body side end 6, which is the upper end of the spring 2, elastically abuts against the lower surface of the top mount 20 supported and fixed to the vehicle body B. Meanwhile, the wheel side end 7, which is the lower end of the spring 2, elastically abuts against the upper surface of the spring seat 21 supported on the wheel W via the cylinder 13, lower bracket 16, knuckle, etc.

[0048] In a vehicle equipped with the suspension device 1 of this example, the elastic restoring force of the spring 2 applies a downward elastic force to the spring seat 21, and this elastic force presses the outer surface of the tire that constitutes the wheel W against the road surface.

[0049] Furthermore, in a vehicle equipped with the suspension system 1 of this embodiment, the up and down vibration of the cylinder 13 due to vibration from the wheels W or the like is absorbed by the elastic deformation of the spring 2 .

[0050] The vehicle height adjustment mechanism 4 includes an electric motor 3 , a reverse input cutoff clutch 5 , and a spring adjustment mechanism 22 .

[0051] The electric motor 3 has a motor output shaft 8 .

[0052] The reverse input cutoff clutch 5 has a clutch input member 10 that is rotationally driven based on the rotation of the motor output shaft 8, and a clutch output member 11. When rotational torque is input to the clutch input member 10, the reverse input cutoff clutch 5 transmits the rotational torque input to the clutch input member 10 to the clutch output member 11, but when rotational torque is input in reverse to the clutch output member 11, the reverse input cutoff clutch 5 does not transmit the rotational torque input in reverse to the clutch output member 11 to the clutch input member 10.

[0053] The spring adjustment mechanism 22 moves or rotates the spring 2 in the vertical direction in accordance with the rotation of the clutch output member 11 .

[0054] The vehicle height adjustment mechanism 4 adjusts the vehicle height by moving or rotating the spring 2 in the vertical direction using the spring adjustment mechanism 22 based on the rotational driving of the motor output shaft 8 .

[0055] The spring adjustment mechanism 22 is configured to move or rotate the spring 2 in the vertical direction depending on the type, arrangement, etc. of the spring 2. Specifically, when the spring 2 is configured as a coil spring, the spring adjustment mechanism 22 is configured to move the spring 2 in the vertical direction. When the spring 2 is configured as a torsion bar, the spring adjustment mechanism 22 is configured to rotate the spring 2.

[0056] In this example, the spring 2 is a coil spring. The spring 2 is disposed around a damper 12, which is provided as an optional component. More specifically, the spring 2 and the damper 12 are disposed substantially coaxially.

[0057] The damper 12 is disposed in parallel with the spring 2 between the vehicle body B and the wheel W, and absorbs and reduces vibrations of the spring 2. The damper 12 includes a cylinder 13 supported by the wheel W, and a piston 14 supported by the vehicle body B and fitted in the cylinder 13.

[0058] The cylinder 13 has a cylindrical shape. The cylinder 13 has a cylinder space 15 therein. Oil is accommodated in the cylinder space 15. A lower end of the cylinder 13 is connected and fixed via a lower bracket 16 to a knuckle that supports the wheel W.

[0059] The piston 14 includes a head portion 17 and a rod portion 18 .

[0060] The head portion 17 is fitted inside the cylinder space 15 so as to be movable in the up and down direction.

[0061] The rod portion 18 protrudes upward from the upper surface of the head portion 17 and passes through an upper plate portion 19 of the cylinder 13. The upper end of the rod portion 18 is coupled and fixed to a top mount 20 that is supported and fixed to the vehicle body B.

[0062] When implementing the suspension system according to one aspect of the present disclosure, the damper 12 may have either a single-tube structure or a double-tube structure.

[0063] The suspension system 1 of this example includes a spring seat 21 that is supported so as to be movable relative to the cylinder 13 in the vertical direction but not to be rotated relative to the cylinder 13. The spring seat 21 is disposed around the cylinder 13.

[0064] In this example, a protrusion 61 on the outer peripheral surface of the cylinder 13 is engaged with a recessed groove 60 on the inner peripheral surface of the spring seat 21, thereby supporting the spring seat 21 so that it can move up and down relative to the cylinder 13 but cannot rotate relative to the cylinder 13. When implementing a suspension device according to one aspect of the present disclosure, the protrusion on the inner peripheral surface of the spring seat can also be engaged with a recessed groove on the outer peripheral surface of the cylinder. In either case, the combination of the protrusion and the recessed groove can be provided at only one location in the circumferential direction, or at multiple locations in the circumferential direction. The protrusion and the recessed groove can also be omitted.

[0065] The spring adjustment mechanism 22 of this example is configured to move the spring 2 in the vertical direction by moving the spring seat 21 in the vertical direction. Specifically, the spring adjustment mechanism 22 is configured to convert the rotational movement of the clutch output member 11 into the vertical movement of the spring seat 21 relative to the cylinder 13.

[0066] The spring adjustment mechanism 22 can have any configuration as long as it can convert rotational motion into linear motion. For example, the spring adjustment mechanism 22 can be configured with a feed screw mechanism such as a slide screw mechanism or a ball screw mechanism, or a cam mechanism that expands or contracts the axial dimension based on the rotation of a drive cam. In this example, the spring adjustment mechanism 22 is configured with a ball screw mechanism.

[0067] The spring adjustment mechanism 22 includes a nut 23 and a plurality of balls 24 .

[0068] The nut 23 has an outer diameter side ball screw groove 26 on its inner peripheral surface and is rotationally driven based on the rotation of the clutch output member 11. The outer diameter side ball screw groove is formed in a spiral shape. In this example, the nut 23 is supported to allow relative movement and rotation in the vertical direction relative to the cylinder 13 and to allow vertical movement integrally with the spring seat 21. More specifically, the nut 23 is supported around a portion of the cylinder 13 that is located below the spring seat 21 to allow relative movement and rotation in the vertical direction. The spring seat 21 is mounted on the upper end face of the nut 23 via a bearing 27.

[0069] The bearing 27 has a function of supporting the thrust load between the spring seat 21 and the nut 23. As long as it has this function, the type of bearing is not particularly limited, and it can be a rolling bearing such as a thrust needle bearing, a sliding bearing, or the like.

[0070] A driven gear portion 28 is provided around the nut 23. The driven gear portion 28 is formed on the outer peripheral surface of the nut 23 directly or via a member separate from the nut 23.

[0071] The driven-side gear portion 28 meshes with a driving-side gear portion 30 provided around an intermediate shaft 29. The intermediate shaft 29 is connected to the motor output shaft 8 of the electric motor 3 via the reverse input cut-off clutch 5 so as to be able to transmit torque.

[0072] Specifically, the motor output shaft 8 is connected and fixed to a clutch input member 10 of the reverse input cutoff clutch 5, or is configured integrally with the clutch input member 10. The intermediate shaft 29 is connected and fixed to a clutch output member 11 of the reverse input cutoff clutch 5, or is configured integrally with the clutch output member 11.

[0073] The plurality of balls 24 are arranged to be able to roll between an inner diameter side ball screw groove 25 and an outer diameter side ball screw groove 26, which are provided on the outer peripheral surface of the cylinder 13 or the outer peripheral surface of a member supported and fixed to the cylinder 13. In this example, the inner diameter side ball screw groove 25 is provided on the outer peripheral surface of the cylinder 13 in the middle in the vertical direction.

[0074] The start point and end point of the load path are connected by a circulation path formed on the inner circumferential surface of the nut 23 or formed in a circulation part supported by the nut 23. After reaching the end point of the load path, the ball 24 returns to the start point of the load path through the circulation path. The start point and end point of the load path are interchanged depending on the direction of movement of the nut 23 relative to the cylinder 13.

[0075] In this example, the rotation of the motor output shaft 8 is converted into vertical movement of the nut 23 by the spring adjustment mechanism 22, and by moving the spring seat 21 vertically together with the nut 23, the vertical position of the spring seat 21 can be adjusted.

[0076] The controller 51 controls the electric motor 3 .

[0077] To adjust the vehicle height in a vehicle equipped with the suspension system 1 of this example, the electric motor 3 is energized based on a command from the controller 51 to rotate the motor output shaft 8. The rotation of the motor output shaft 8 is transmitted to the intermediate shaft 29 via the reverse input cut-off clutch 5. The rotation of the intermediate shaft 29 is transmitted to the nut 23 via the meshing portion between the drive-side gear portion 30 and the driven-side gear portion 28. As the nut 23 rotates, the plurality of balls 24 circulate through the circulation path and roll in the load path, thereby moving the nut 23 up and down relative to the cylinder 13.

[0078] When the nut 23 moves up and down, the spring seat 21 mounted on the upper end surface of the nut 23 via a bearing 27 also moves up and down. When the spring seat 21 moves up and down, the top mount 20 mounted on the upper surface of the spring seat 21 via a spring 2 also moves up and down together with the piston 14. As a result, the vehicle body B to which the top mount 20 is connected and fixed moves up and down, and the vehicle height is adjusted.

[0079] After the vehicle height is adjusted to the target value, the power supply to the electric motor 3 is stopped.

[0080] When the outer peripheral surface of the tire that constitutes the wheel W is in contact with the road surface, a vertical force is applied to the spring seat 21 based on the weight of the vehicle body B and the occupant, the elasticity of the spring 2, etc. This force causes the nut 23 to move vertically, and a rotational torque is applied to the nut 23. The rotational torque applied to the nut 23 is transmitted to the intermediate shaft 29 via the meshing portion between the drive-side gear portion 30 and the driven-side gear portion 28.

[0081] Because the intermediate shaft 29 is connected and fixed to the clutch output member 11 or is configured integrally with the clutch output member 11, the rotational torque of the intermediate shaft 29 is supported by the reverse input cutoff clutch 5. This prevents the rotation of the intermediate shaft 29 and the nut 23, and also prevents the vertical movement of the spring seat 21 and the nut 23. As a result, the vehicle height is maintained constant even when the power supply to the electric motor 3 is stopped.

[0082] (Explanation of the Structure of the Reverse Input Cutoff Clutch) An example of the reverse input cutoff clutch 5 applicable to the suspension system 1 of this example will be described in more detail below. However, when implementing the suspension system of one aspect of the present disclosure, the reverse input cutoff clutch 5 is not limited to the structure of this example, and any structure can be adopted as long as it has the above-mentioned function. The reverse input cutoff clutch 5 of this example includes a pressed member 31, a clutch input member 10, a clutch output member 11, and an engager 32.

[0083] The pressed member 31 has an inner peripheral surface which is a pressed surface 33. In this example, the pressed surface 33 is formed of a cylindrical surface whose inner diameter does not change in the axial direction.

[0084] The pressed member 31 is fixed to a fixed member such as a motor housing that accommodates the electric motor 3, or is provided integrally with the fixed member, and its rotation is restricted.

[0085] The clutch input member 10 has an input side engaging portion 34 arranged radially inside the pressed surface 33 and is arranged coaxially with the pressed surface 33 .

[0086] The input side engaging portion 34 is provided at a portion radially outwardly away from the rotation center O of the clutch input member 10, and is arranged at a position where it can engage with the input side engaged portion 45 of the engager 32. The input side engaging portion 34 is configured to engage with the input side engaged portion 45 as the clutch input member 10 or the engager 32 rotates.

[0087] In this example, the clutch input member 10 has a base plate portion 35 and an input shaft portion 36 in addition to the input side engaging portion 34 .

[0088] The base plate portion 35 has a substantially circular end face shape when viewed in the axial direction.

[0089] The input shaft portion 36 protrudes axially from the center of a side surface on one axial side (the right side in FIG. 3 ) of the base portion 35. The input shaft portion 36 is either coupled and fixed to the motor output shaft 8 or is configured integrally with the motor output shaft 8.

[0090] The number of input side engaging portions 34 is determined according to the number of engaging elements 32 , and when the engaging elements 32 are made up of a plurality of engaging elements 32 , the input side engaging portion 34 is also made up of a plurality of input side engaging portions 34 .

[0091] In this example, the engaging elements 32 are configured by two engaging elements 32. Therefore, the input side engaging portion 34 is configured by two input side engaging portions 34 in accordance with the number of engaging elements 32.

[0092] The two input side engaging portions 34 are arranged at two radially opposite positions on the side surface on the other axial side (left side in Figure 3) of the base portion 35, and are spaced apart from each other in the radial direction of the clutch input member 10.

[0093] Each input-side engaging portion 34 has a circumferentially symmetrical shape. In this example, each input-side engaging portion 34 has an end face shape that is generally fan-shaped or generally trapezoidal, with the circumferential width increasing radially outward when viewed from the axial direction.

[0094] Specifically, the radially inner surfaces 37 of the two input side engaging portions 34 are formed of flat surfaces that are parallel to each other.

[0095] The radially outer surfaces 38 of the two input-side engaging portions 34 are configured as partial cylindrical surfaces. In this example, each of the radially outer surfaces 38 has a radius of curvature that is half the outer diameter of the base plate portion 35. In other words, the outer peripheral surface of the base plate portion 35 and the radially outer surfaces 38 of the two input-side engaging portions 34 exist on the same imaginary cylindrical surface.

[0096] The two circumferential side surfaces 39 of each input side engaging portion 34 are configured as flat surfaces that are inclined in directions that move away from each other as they extend radially outward.

[0097] The clutch output member 11 has an output-side engaging portion 40 that is arranged radially inward of the pressed surface 33 and radially inward of the input-side engaging portion 34, and is arranged coaxially with the pressed surface 33. In other words, the clutch output member 11 is also arranged coaxially with the clutch input member 10.

[0098] The output side engaging portion 40 has a portion that is radially inward of the input side engaging portion 34 and radially outward from the rotation center O of the clutch output member 11, and this portion is arranged in a position where it can engage with the output side engaged portion 46 of the engager 32. The output side engaging portion 40 is configured so that this portion engages with the output side engaged portion 46 as the clutch output member 11 or the engager 32 rotates.

[0099] In this example, the clutch output member 11 has an output shaft portion 41 in addition to the output side engaging portion 40. The output shaft portion 41 is either coupled and fixed to the intermediate shaft 29 or is configured integrally with the intermediate shaft 29.

[0100] The number of portions of the output side engaging portion 40 that engage with the output side engaged portion of the engaging element 32 is determined according to the number of engaging elements 32, and when the engaging element 32 is composed of multiple engaging elements 32, the output side engaging portion 40 is configured to have multiple engaging portions.

[0101] In this example, the output side engaging portion 40 is configured to have portions that engage with two output side engaged portions 46 in accordance with the number of the engaging pieces 32 .

[0102] In this example, the output side engaging portion 40 has a substantially rectangular or oval end face shape when viewed in the axial direction, and protrudes from the center of one axial end face of the output shaft portion 41 toward one axial side. In other words, the distance from the rotation center O of the clutch output member 11 to the outer circumferential surface of the output side engaging portion 40, which is the portion that engages with the output side engaged portion 46, is not constant in the circumferential direction. Therefore, the output side engaging portion 40 has a cam function.

[0103] More specifically, the outer peripheral surface of the output side engaging portion 40 is made up of two parallel flat surfaces 42 and two partially cylindrical convex surfaces 43. The two convex surfaces 43 are made up of partially cylindrical surfaces centered on the rotation center O of the clutch output member 11.

[0104] The output side engagement portion 40 is plane-symmetrical with respect to a first imaginary plane that includes the rotation center O of the clutch output member 11 and is perpendicular to the flat surface 42, and is plane-symmetrical with respect to a second imaginary plane that includes the rotation center O of the clutch output member 11 and is parallel to the flat surface 42.

[0105] The output side engaging portion 40 is disposed between the two input side engaging portions 34 .

[0106] The engaging element 32 has a pressing surface 44 facing the pressed surface 33, an input side engaged portion 45 that can engage with the input side engaging portion 34, and an output side engaged portion 46 that can engage with the output side engaging portion 40, and is arranged so as to be able to move in a first direction, which is the direction towards or away from the pressed surface 33.

[0107] When rotational torque is input to the clutch input member 10, the input side engaging portion 34 engages with the input side engaged portion 45, and the engaging element 32 moves in the first direction away from the pressed surface 33, thereby engaging the output side engaged portion 46 with the output side engaging portion 40, thereby transmitting the rotational torque input to the clutch input member 10 to the clutch output member 11.When rotational torque is input in the reverse direction to the clutch output member 11, the output side engaging portion 40 engages with the output side engaged portion 46, and the pressing surface 44 is pressed against the pressed surface 33, causing frictional engagement of the pressing surface 44 with the pressed surface 33.

[0108] As long as the engaging element 32 has such a configuration, it may be configured with one engaging element 32 or with two or more engaging elements 32 .

[0109] In this example, the engaging element 32 is composed of two engaging elements 32. Each engaging element 32 functions as an engaging element 32. Each engaging element 32 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 (the direction indicated by arrow B in FIG. 4). The configuration of each engaging element 32 will be described below.

[0110] In this example, the radial direction with respect to the engaging element 32 is the direction in which the pressing surface 44 approaches or moves away from the pressed surface 33, and corresponds to the direction indicated by arrow A in Fig. 4. The width direction with respect to the engaging element 32 is the direction perpendicular to both the direction in which the pressing surface 44 approaches or moves away from the pressed surface 33 and the axial direction of the clutch input member 10, and corresponds to the direction indicated by arrow B in Fig. 4. In this example, the radial direction with respect to the engaging element 32 corresponds to the first direction, and the width direction with respect to the engaging element 32 corresponds to the second direction.

[0111] The pressing surface 44 is provided on the radially outer surface of the engaging element 32 facing the pressed surface 33. In this example, the pressing surface 44 is configured by two pressing surfaces 44 provided at two positions spaced apart from each other in the circumferential direction on the radially outer surface of the engaging element 32. Each pressing surface 44 is configured by a partially cylindrical convex curved surface having a radius of curvature smaller than the radius of curvature of the pressed surface 33.

[0112] When viewed from the axial direction, the portion of the radially outer surface of the engaging element 32 that is circumferentially deviated from the two pressing surfaces 44 is located radially inward of an imaginary circle that is centered on the central axis O of the clutch input member 10 and that is tangent to the two pressing surfaces 44. In other words, when the two pressing surfaces 44 are in contact with the pressed surface 33, the portion that is circumferentially deviated from the two pressing surfaces 44 does not contact the pressed surface 33.

[0113] The pressing surface 44 preferably has a surface property that has a higher coefficient of friction with the pressed surface 33 than the other portions of the engaging element 32. The pressing surface 44 may be formed integrally with the other portions of the engaging element 32, or may be formed by the surface of a friction material fixed to the other portions of the engaging element 32 by sticking, bonding, or the like.

[0114] In this example, the input-side engaged portion 45 is provided in a radially intermediate portion of the widthwise center portion of the engaging element 32. More specifically, although not limited to this, the input-side engaged portion 45 has a substantially arch-shaped opening when viewed in the axial direction, and is configured as a through-hole that axially passes through a radially intermediate portion of the widthwise center position of the engaging element 32.

[0115] The input-side engaged portion 45 has a size that allows the input-side engaging portion 34 to be loosely inserted therein. Therefore, with the input-side engaging portion 34 inserted inside the input-side engaged portion 45, there is a gap between the input-side engaging portion 34 and the inner surface of the input-side engaged portion 45 in both the width direction and the radial direction of the engaging element 32. Therefore, the input-side engaging portion 34 can be displaced relative to the input-side engaged portion 45 in the rotational direction of the clutch input member 10, and the input-side engaged portion 45 can be displaced relative to the input-side engaging portion 34 in the radial direction of the engaging element 32.

[0116] The shape of the input-side engaged portion 45 is not limited as long as it is configured to be able to engage with the input-side engaging portion 34. Although not limited thereto, in this example, the input-side engaged portion 45 has, on its radially outward surface, a flat surface 47 that is parallel to the flat surface portion 49 provided on the radially inner surface of the engaging element 32, and, on its radially inward surface, a partially cylindrical concave curved surface 48.

[0117] Alternatively, the input side engaged portion 45 can be configured as a bottomed hole that opens only to one axial side of the engaging element 32, or the input side engaged portion 45 can be configured as a notch that opens to the radially outer surface of the engaging element 32.

[0118] In this example, the output-side engaged portion 46 is provided at the center in the width direction of the radially inner surface of the engaging element 32. The shape of the output-side engaged portion 46 is not limited as long as it is configured to be able to engage with the output-side engaging portion 40.

[0119] In this example, the engaging element 32 has a flat surface portion 49 on its radially inner surface, and two protrusions 50 protruding radially inward at two widthwise positions on the flat surface portion 49. The output-side engaged portion 46 is formed by a portion of the flat surface portion 49 that is located between the two protrusions 50 in the widthwise direction. Although not limited to this, the widthwise dimension of the output-side engaged portion 46, i.e., the distance between the two protrusions 50, is larger than the widthwise dimension of the flat surface 42 of the output-side engaging portion 40.

[0120] In the reverse input cutoff clutch 5 of this example, the pressing surfaces 44 of the two engaging elements 32 are oriented radially opposite to each other, and the flat surface portions 49 are opposed to each other. Each engaging element 32 is arranged radially inward of the pressed member 31 so as to be movable in a first direction, which is the radial direction of each engaging element 32 and corresponds to the direction in which the pressing surfaces 44 move toward and away from the pressed surface 33. Furthermore, the two input-side engaging portions 34 of the clutch input member 10 arranged on one axial side are axially inserted into the input-side engaged portions 45 of the two engaging elements 32, and the output-side engaging portion 40 of the clutch output member 11 arranged on the other axial side is axially inserted between the output-side engaged portions 46 of the two engaging elements 32. In other words, the two engaging elements 32 are arranged so that the output-side engaging portions 40 are sandwiched from the radially outer side by the output-side engaged portions 46.

[0121] When the two engaging elements 32 are positioned radially inside the pressed member 31, the inner diameter dimension of the pressed member 31 and the radial dimension of the engaging elements 32 are regulated so that a gap exists in at least one of the areas between the pressed surface 33 and the two pressing surfaces 44, and between the tip surfaces of the convex portions 50 constituting each pair of two pairs of convex portions 50 formed by the two convex portions 50 of the two engaging elements facing each other.

[0122] The reverse input cutoff clutch 5 of this example can further include a biasing member 52 (shown only in FIG. 4 ) that elastically biases the engaging element 32 in a direction that brings the pressing surface 44 closer to the pressed surface 33. The biasing member 52 elastically biases the engaging element 32 in a direction that brings the pressing surface 44 closer to the pressed surface 33 so that the pressing surface 44 of the engaging element 32 comes into contact with the pressed surface 33 in a neutral state in which no torque is applied to either the clutch input member 10 or the clutch output member 11.

[0123] Although not limited to this, the urging member 52 can be configured by two urging members 52 arranged at two positions in the width direction between the flat surface portions 49 of the two engaging elements 32. More specifically, each of the two urging members 52 is configured by a compression coil spring, and can be sandwiched in an elastically compressed state between the flat surface portions 49 of the two engaging elements 32. Each of the two urging members 52 is arranged in a state where it is prevented from falling off by inserting a convex portion 50 into the inside of each of the two pairs of convex portions 50 constituting the respective pair on both ends in the length direction.

[0124] Alternatively, the biasing member can be disposed between the flat surface portions 49 of the engagement elements 32 and the clutch output member 11. In this case, the biasing member can be configured by two biasing members disposed between the flat surface portions 49 of the two engagement elements 32 and the clutch output member 11. Specifically, each of the two biasing members can be configured by a leaf spring and can be locked to the two engagement elements 32.

[0125] (Explanation of Operation of Reverse Input Cutoff Clutch) The operation of the reverse input cutoff clutch 5 will be explained using Figures 5 and 6. Note that Figures 5 and 6 show exaggerated radial gaps between the clutch input member 10 and the two engaging elements 32, and between the clutch output member 11 and the two engaging elements 32.

[0126] When rotational torque is input to the clutch input member 10, the two engagers 32 move in a direction away from the pressed surface 33, regardless of the rotational direction of the clutch input member 10. More specifically, as shown in Figure 5, the input-side engaging portion 34 rotates inside the input-side engaged portion 45 in the rotational direction of the clutch input member 10 (counterclockwise in the example of Figure 5). This reduces the gap between the radially inner surface 37 of the input-side engaging portion 34 and the flat surface 47 of the input-side engaged portion 45, and brings the radially inner surface 37 of the input-side engaging portion 34 into contact with the flat surface 47 of the input-side engaged portion 45.

[0127] When the clutch input member 10 rotates further from this state, the flat surface 47 is pressed radially inward by the radially inner surface 37, and the engaging elements 32 move in a direction away from the pressed surface 33. In other words, the two engaging elements 32 move radially inward, that is, toward each other, based on their engagement with the clutch input member 10, and the radially inner surfaces 37 of the two engaging elements 32 approach each other, and the output-side engaging portion 40 of the clutch output member 11 is clamped from both radial sides by the output-side engaged portions 46 of the two engaging elements 32.

[0128] In this way, the clutch output member 11 is rotated so that the flat surface 42 of the output side engaging portion 40 is parallel to the flat surface portion 49 of the engaging element 32, and the output side engaging portion 40 and the output side engaged portion 46 of the engaging element 32 are engaged without rattle. As a result, the rotational torque input to the clutch input member 10 is transmitted to the clutch output member 11 via the two engaging elements 32 and is output from the clutch output member 11.

[0129] When a rotational torque is input in reverse to the clutch output member 11, the two engaging elements 32 move in a direction approaching the pressed surface 33, regardless of the rotational direction of the clutch output member 11. More specifically, as shown in Figure 6, the output-side engaging portion 40 rotates in the rotational direction of the clutch output member 11 (clockwise in the example of Figure 6) inside the output-side engaged portions 46 of the two engaging elements 32. The output-side engaged portions 46 are pressed radially outward by a corner portion of the outer circumferential surface of the output-side engaging portion 40, which is the connection portion between the flat surface 42 and the convex curved surface 43, and the two engaging elements 32 move in a direction approaching the pressed surface 33.

[0130] That is, based on the engagement with the clutch output member 11, the two engaging elements 32 move radially outward, i.e., in directions away from each other, and the pressing surfaces 44 of the two engaging elements 32 come into contact with the pressed surface 33 and frictionally engage with the pressed surface 33. As a result, the rotational torque reversely input to the clutch output member 11 is completely blocked and is no longer transmitted to the clutch input member 10.

[0131] In the reverse input cutoff clutch 5 of this example, the size of the gap between each component is adjusted to enable the above operation. In particular, in a positional relationship in which the pressing surfaces 44 of the two engaging elements 32 are in contact with the pressed surface 33, a gap is provided between the radially inner surface 37 of the input-side engaging portion 34 and the flat surface 47 of the input-side engaged portion 45 that allows the pressing surface 44 to be further pressed toward the pressed surface 33 as the corners of the output-side engaging portion 40 press against the output-side engaged portion 46.

[0132] This prevents the input side engaging portion 34 from blocking the radially outward movement of the engaging element 32 when a rotational torque is input in reverse to the clutch output member 11, and even after the pressing surface 44 comes into contact with the pressed surface 33, the surface pressure acting on the contact point between the pressing surface 44 and the pressed surface 33 changes depending on the magnitude of the rotational torque input in reverse to the clutch output member 11, thereby ensuring that the clutch output member 11 is locked properly.

[0133] In the reverse input cutoff clutch 5 of this example, rotation of both the clutch input member 10 and the clutch output member 11 is converted into radial movement of the engager 32. The reverse input cutoff clutch 5 is configured so that, as the engager 32 moves radially, the engager 32 engages with the clutch output member 11 located radially inward of the engager 32, or the engager 32 is pressed against the pressed member 31 located radially outward of the engager 32. That is, in the reverse input cutoff clutch 5 of this example, the radial movement of the engager 32 is controlled by the rotation of each of the clutch input member 10 and the clutch output member 11, and the clutch output member 11 is switched between an unlocked state in which rotational torque can be transmitted from the clutch input member 10 to the clutch output member 11, and a locked state in which rotation of the clutch output member 11 is prevented. This allows the axial dimension of the entire reverse input cutoff clutch 5 to be shortened.

[0134] (Explanation of dimensional relationships between each part of the reverse input cut-off clutch) In the reverse input cut-off clutch 5 of this example, the dimensions and shapes of each part constituting the clutch input member 10, the clutch output member 11, and the two engaging members 32 are regulated so as to satisfy the following relationships.

[0135] First, as the clutch output member 11 rotates in a predetermined direction (for example, the clockwise direction in FIG. 4), the two pressing surfaces 44 of the engaging element 32 are pressed against the pressed surface 33, and as the clutch input member 10 rotates in a direction opposite to the predetermined direction (for example, the counterclockwise direction in FIG. 4), the input side engaging portion 34 and the input side engaged portion 45 are engaged with each other, that is, a part of the input side engaging portion 34 is in contact with the input side engaged portion 45. In this state, the contact portion P ｉｎ and a first distance D, which is the distance in the second direction between the center of rotation O of the clutch input member 10 and the １ However, the contact portion P between the output side engaging portion 40 and the output side engaged portion 46 ｏｕｔ and a second distance D in the second direction between the rotation center O of the clutch output member 11 and the ２ (D １ >D ２ ).

[0136] 6, when a rotational torque is input in reverse to the clutch output member 11 and the two pressing surfaces 44 of the engaging element 32 are in contact with the pressed surface 33, the contact portion C between the output side engaging portion 40 and the output side engaged portion 46 is in a locked state. １ However, one of the two pressing surfaces 44, specifically, the contact portion C １ The contact portion C between the pressing surface 44 on the side closer to the pressed surface 33 ２ and the rotation center O of the clutch output member 11 in the first direction (lower side in FIG. 6 ).

[0137] In the reverse input cutoff clutch 5 of this example, when torque in a predetermined direction (clockwise in FIGS. 7A and 7B) is being reversely input to the clutch output member 11, the clutch input member 10 can be rotated in the same direction as the predetermined direction to smoothly switch from the locked state to the unlocked state. The reason for this will be explained with reference to FIGS. 7A and 7B.

[0138] When torque is input to the clutch input member 10 in the locked state of the reverse input cutoff clutch 5, the two engaging elements 32 are respectively in contact with the contact portion C １ It tends to rotate around the center.

[0139] Contact part C １ is located farther from the rotation center O of the clutch output member 11 in the first direction than the virtual line L, as shown in FIG. 7B, when a clockwise rotational torque is input to the clutch input member 10, the engaging element 32 contacts the contact portion C １ The contact point C tends to rotate clockwise. １ is located on the side farther from the rotation center O of the clutch output member 11 in the first direction than the virtual line L, the contact portion C １ and contact part C ２ Since the distance between the contact points C and C is relatively large, as shown by the locus r in FIG. 7B with a dashed line, the contact points C １ The pressing surface 44 located on the side closer to the pressing surface 33 (the left side of FIG. 7B) tends to be pressed strongly against the pressed surface 33 and bite into it.

[0140] Therefore, the contact part C １ However, in a structure in which the imaginary line L is positioned farther from the center of rotation O of the clutch output member 11 in the first direction, when torque in a predetermined direction is reversely input to the clutch output member 11, the clutch input member 10 must be rotated in the same direction as the predetermined direction to switch the reverse input cut-off clutch 5 from a locked state to an unlocked state, thereby releasing the engagement of one of the pressing surfaces 44 with the pressed surface 33. As a result, the instantaneous maximum torque (peak torque) of the electric motor 3 for rotationally driving the clutch input member 10 becomes excessively large.

[0141] As in the reverse input cutoff clutch 5 of this example, the contact portion C １ However, even if the imaginary line L is located closer to the rotation center O of the clutch output member 11 in the first direction than the imaginary line L, when a clockwise rotational torque is input to the clutch input member 10, as shown in FIG. 7A, the engaging element 32 moves to the contact portion C. １ The contact point C tends to rotate clockwise. １ is located closer to the rotation center O of the clutch output member 11 in the first direction than the virtual line L, the contact portion C １ and contact part C ２ Since the distance between the two is relatively small, the locus r １ , r ２ As shown in FIG. 1, neither of the two pressing surfaces 44 is pressed against the pressed surface 33 .

[0142] Therefore, the contact part C １However, in a structure in which the imaginary line L is positioned closer to the center of rotation O of the clutch output member 11 in the first direction than the imaginary line L, by rotating the clutch input member 10 in the same direction as the predetermined direction when torque in the predetermined direction is reversely input to the clutch output member 11, it is possible to suppress an instantaneous increase in rotational torque of the clutch input member 10 even when switching the reverse input cutoff clutch 5 from a locked state to an unlocked state. Therefore, compared to the structure shown in Figure 7(B), the reverse input cutoff clutch 5 of this example can smoothly switch from a locked state to an unlocked state by rotating the clutch input member 10 in the same direction as the predetermined direction when torque in the predetermined direction is reversely input to the clutch output member 11.

[0143] Furthermore, the reverse input cutoff clutch 5 of this embodiment can smoothly switch from the unlocked state to the locked state, the reason for which will be explained with reference to FIG.

[0144] Figure 7(C) shows a state in which torque in a predetermined direction (clockwise in Figure 7(C)) is input to the clutch output member 11 in reverse, and torque in the direction opposite to the predetermined direction (counterclockwise in Figure 7(C)) is applied to the clutch input member 10.

[0145] When a counterclockwise torque is input to the clutch input member 10, the engaging element 32 moves to the contact portion C １ 7C, the clutch output member 11 tends to rotate counterclockwise around the center of rotation O of the clutch output member 11. １ The other pressing surface 44 located on the opposite side (the right side in FIG. 7C ) tends to be pressed against the pressed surface 33 .

[0146] Therefore, in the reverse input cutoff clutch 5 of this example, when switching from an unlocked state in which torque is transmitted from the clutch input member 10 to the clutch output member 11 to a locked state by applying torque to the clutch input member 10 in a direction opposite to the predetermined direction while torque in the predetermined direction is being reversely input to the clutch output member 11, the amount of movement of the engaging element 32 in the second direction that is required to press the pressing surface 44 against the pressed surface 33 is kept relatively small. Therefore, the reverse input cutoff clutch 5 of this example can quickly switch from the unlocked state to the locked state.

[0147] However, when the suspension system according to one aspect of the present disclosure is implemented, the reverse input cutoff clutch 5 has a first distance D １ is the second distance D ２ and the contact area C １ However, it is also possible to use a reverse input cutoff clutch that is located farther from the rotation center O of the clutch output member 11 in the first direction than the virtual line L. Alternatively, the reverse input cutoff clutch 5 may be configured such that the first distance D １ is the second distance D ２ A smaller reverse input disconnect clutch may also be used.

[0148] (Explanation of Function for Preventing Jerking in Reverse Input Disconnect Clutch) In the suspension system 1 of this example, in order to smoothly adjust the vehicle height, the controller 51 has a function of preventing jerking in the reverse input disconnect clutch 5. In other words, when adjusting the vehicle height, if the direction of the rotational torque reversely input to the clutch output member 11 is the same as the direction in which the clutch input member 10 is rotated and the rotation speed of the clutch input member 10 is within a rotation speed range below a predetermined threshold value in which jerking is likely to occur, the controller 51 has a function of controlling the electric motor 3 so that the electric motor 3 can quickly pass through that rotation speed range.

[0149] First, the mechanism by which the jerking phenomenon occurs will be described.

[0150] In the suspension system 1 , a force (rotational torque) that tends to rotate the clutch output member 11 is applied to the clutch output member 11 based on the weight of the vehicle body B and the occupant and the elastic force of the spring 2 .

[0151] In a suspension system like the suspension system 1 of this example, which adjusts vehicle height by vertically moving the spring 2 made of a coil spring, a downward force is constantly applied to the spring seat 21 based on the weight of the vehicle body B and occupant, the elasticity of the spring, and the like, in a normal state except when the vehicle is being jacked up, and based on this force, a rotational torque in a predetermined direction (for example, the clockwise direction in Figures 8(A) to 8(C)) is constantly applied to the clutch output member 11. Therefore, in the suspension system of this example, the direction of the rotational torque that is reversely input to the clutch output member 11 based on the weight of the vehicle body B and occupant coincides with the direction of the torque imparted to the clutch input member 10 when lowering the vehicle height.

[0152] In the suspension system 1 of this example, when lowering the vehicle height, the motor output shaft 8 is rotationally driven to rotate the clutch input member 10 in the predetermined direction, as shown in the order of Figures 8(A) and 8(B). At this time, if the rotation speed of the clutch output member 11 is greater than the rotation speed of the clutch input member 10, the output side engaging portion 40 presses the output side engaged portion 46 radially outward, and the pressing surface 44 frictionally engages with the pressed surface 33, thereby locking the rotation of the clutch input member 10 and the clutch output member 11, as shown in the order of Figures 8(B) and 8(C).

[0153] Even in this state, torque is input to the clutch input member 10 from the motor output shaft 8, so the next moment, as shown in Figure 8 (B), the reverse input cutoff clutch 5 switches from the locked state to the unlocked state.

[0154] In this way, when torque is input to the clutch output member 11 in the reverse direction and torque is input to the clutch input member 10 in the same direction as the torque being input to the clutch output member 11 in the reverse direction, a jerking phenomenon may occur in which the clutch input member 10 and the clutch output member 11 rotate intermittently, alternating in a short period of time between an unlocked state in which torque can be transmitted between the clutch input member 10 and the clutch output member 11 and a locked state in which torque cannot be transmitted between the clutch input member 10 and the clutch output member 11.

[0155] When starting control to adjust the vehicle height in a direction to rotate the clutch input member 10 in the same direction as the rotational torque (reverse input torque) that is reversely input to the clutch output member 11 from a state in which the reverse input cut-off clutch 5 is locked due to the rotational torque in the predetermined direction being reversely input to the clutch output member 11, the controller 51 adjusts the motor output shaft 8 at a first rotational acceleration a １ and the rotation speed R of the clutch input member 10 ｉｎ is a predetermined first threshold T １ When the rotational acceleration of the motor output shaft 8 becomes larger than the first rotational acceleration a １ A second rotational acceleration a smaller than ２ By executing the first function of switching to the first function, it is possible to prevent the occurrence of the jerking phenomenon in the initial stage of the control.

[0156] The initial stage of the control is the stage immediately after the electric motor 3 is started and the rotation speed R of the clutch input member 10 is increased. ｉｎ is a predetermined first threshold T １ This is the stage until the predetermined first threshold T １ is the rotational speed R of the clutch input member 10 that is sufficient to prevent the occurrence of the jerking phenomenon in the reverse input disconnection clutch 5. ｉｎ and can be found in advance through experiments and calculations.

[0157] First rotational acceleration a １ and the second rotational acceleration a ２ Each of the above values ​​can be set to a predetermined value in advance, or can be determined on an as-needed basis depending on the current vehicle height, the target vehicle height, etc.

[0158] First rotational acceleration a １ In order to quickly pass through the rotational speed range where the jerking phenomenon is likely to occur, it is preferable to make the rotational acceleration of the motor output shaft 8 as large as possible within an adjustable range.

[0159] Second rotational acceleration a ２ is set to an appropriate value depending on the reduction ratio between the driving gear portion 30 and the driven gear portion 28, in order to prevent the occupant from feeling uncomfortable.

[0160] The controller 51 can be configured to control the motor output shaft 8 by speed control, which controls the rotation speed of the motor output shaft 8 to a target value, or by position control, which controls the rotation position of the motor output shaft 8 to a target position, from the start of the motor output shaft 8 to the end of the control for adjusting the vehicle height to a target value. ｉｎ is a predetermined first threshold T １ In the following range, the motor output shaft 8 is rotated at a rotational acceleration of the first rotational acceleration a １ and R of the clutch input member 10. ｉｎ is a predetermined first threshold T １ After the rotational acceleration becomes larger than the second rotational acceleration a ２ The control is performed by speed control or position control.

[0161] Alternatively, the controller 51 may determine whether the rotation speed R of the clutch input member 10 is greater than the rotation speed R of the motor output shaft 8 after the motor output shaft 8 is started. ｉｎ is a predetermined first threshold T １ In the following range, the motor output shaft 8 is controlled by torque control so that the rotational torque of the motor output shaft 8 becomes a target value, and the rotational speed R of the clutch input member 10 is ｉｎ is a predetermined first threshold T １ After the value of the rotational speed of the motor 100 becomes larger than the value of the rotational speed of the motor 100, the motor output shaft 8 can be controlled by speed control or position control.

[0162] In the electric motor 3 configured by a servo motor capable of controlling torque, position, speed, etc., when the motor output shaft 8 is controlled by torque control, the motor output shaft 8 is generally driven to rotate at a larger rotational acceleration than when controlled by speed control or position control in order to quickly bring the motor output shaft 8 to a target value. Therefore, when the motor output shaft 8 is controlled by torque control, the rotational speed R of the clutch input member 10 is increased from the start of the motor output shaft 8 to the start of the motor output shaft 8. ｉｎ is a predetermined first threshold T １ Rotational acceleration a in the following range １ is the rotation speed R of the clutch input member 10 when the motor output shaft 8 is controlled by speed control or position control. ｉｎ is a predetermined first threshold T １ The rotational acceleration a after it becomes larger than ２ becomes larger than

[0163] Additionally or alternatively, the controller 51 may adjust the rotation speed R of the clutch input member 10 at the final stage of the control for adjusting the vehicle height. ｏｕｔ is a predetermined second threshold T ２ When the direction of the rotational torque (reverse input torque) input to the clutch output member 11 is the same as the rotational direction of the clutch input member 10, the rotational speed R of the clutch input member 10 becomes ｉｎ The second function is to set the target value of 0.

[0164] The end stage of the control is the stage from when the vehicle height approaches the target value until the rotation speed of the clutch input member 10 is reduced to 0, that is, until the clutch input member 10 stops.

[0165] The state in which the vehicle height is approaching the target value means, for example, that the remaining movement amount of the spring seat 21 until the vehicle height reaches the target value is equal to or less than a predetermined amount. This predetermined amount is the amount by which the spring seat 21 moves while the clutch input member 10 is decelerating.

[0166] Also, a predetermined second threshold T ２ is the rotational speed R of the clutch input member 10 that is sufficient to prevent the occurrence of the jerking phenomenon in the reverse input disconnection clutch 5. ｉｎand is obtained in advance by experiment or calculation. ２ is a predetermined first threshold T １ or a predetermined first threshold T １ It can also be different from.

[0167] In the suspension system 1 of this example, the controller 51 has both the first function and the second function. １ and a predetermined second threshold T ２ and are the same threshold value T.

[0168] Specifically, in the suspension system 1 of this example, which adjusts the vehicle height by vertically moving the spring 2 made of a coil spring, when controlling to lower the vehicle height, the rotational speed R of the clutch input member 10 is adjusted from the start of the motor output shaft 8 to the start of the motor output shaft 8. ｉｎ is equal to or less than a predetermined threshold value T, the motor output shaft 8 is controlled by torque control, and the rotation speed R of the clutch input member 10 is ｉｎ becomes larger than the predetermined threshold value T, the motor output shaft 8 is controlled by speed control or position control.

[0169] However, in the suspension system 1 that adjusts the vehicle height by vertically moving the spring 2 made of a coil spring as in this example, when controlling to lower the vehicle height, the rotational speed R of the clutch input member 10 is ｉｎ is equal to or less than a predetermined threshold value T, the motor output shaft 8 is rotated such that the rotational acceleration is equal to the first rotational acceleration a １ and the rotational speed R of the clutch input member 10 is controlled by speed control or position control. ｉｎ is a predetermined first threshold T １ After the rotational acceleration becomes larger than the first rotational acceleration a １ A second rotational acceleration a smaller than ２ and can be controlled by speed control or position control.

[0170] Also, at the end of the control for lowering the vehicle height, the rotation speed R of the clutch input member 10 ｉｎ When the rotation speed R of the clutch input member 10 becomes equal to or less than the predetermined threshold value T,ｉｎ Set the target value to 0.

[0171] The procedure for performing control to lower the vehicle height using the suspension system 1 of this embodiment will be described with reference to the flowchart of FIG.

[0172] First, in step S1, it is determined whether or not the vehicle height is to be lowered. This determination can be made based on the operation of a switch by the driver, for example.

[0173] If it is determined in S1 that the vehicle height adjustment control is not a control to lower the vehicle height, but rather a control to raise the vehicle height, the process proceeds to S1-1, where the vehicle height is adjusted to the target value by speed control or position control, and then the process ends.

[0174] If it is determined in S1 that the vehicle height adjustment control is a control for lowering the vehicle height, the process proceeds to S2, where the motor output shaft 8 and the clutch input member 10 are started by torque control.

[0175] For example, if the suspension device 1 has a stroke sensor, the target value for torque control can be determined by calculating the value of the torque being reversely input to the clutch output member 11 based on the output value of the stroke sensor, and then determining the target value based on that value.

[0176] Alternatively, if the electric motor 3 is configured as a motor capable of detecting the rotational position of the motor output shaft 8, such as a stepping motor, the value of the torque being reversely input to the clutch output member 11 can be calculated based on the rotational position of the motor output shaft 8, and the target value can be determined based on this value.

[0177] Alternatively, if the suspension device 1 has a torque sensor for measuring the rotational torque of the clutch output member 11, the target value for torque control can be determined based on the value of the torque being reversely input to the clutch output member 11 determined by the torque sensor.

[0178] In either case, the relationship between the value of the torque reversely input to the clutch output member 11 and the target value is determined in advance by experiment or calculation, and is stored in the memory of the controller 51 as a map, formula, or the like. Alternatively, the target value can be the product of the value of the torque reversely input to the clutch output member 11 and a predetermined value. The predetermined value is not limited to this, but can be, for example, 0.3 or more and 0.5 or less.

[0179] If the suspension system 1 does not include either a stroke sensor or a torque sensor and the electric motor 3 is not configured as a motor capable of detecting the rotational position of the motor output shaft 8, the target value for torque control is first set to the minimum torque required according to the vehicle specifications. Thereafter, the torque applied to the clutch input member 10 is gradually increased until the reverse input cutoff clutch 5 switches to the unlocked state. Once the reverse input cutoff clutch 5 switches to the unlocked state, the value of the torque applied to the clutch input member 10 is held.

[0180] Whether or not the reverse input cutoff clutch 5 has switched to the unlocked state can be determined based on the current value of the electric motor 3. That is, when the reverse input cutoff clutch 5 switches from the locked state to the unlocked state, the current value of the electric motor 3 decreases.

[0181] Next, in S3, the rotation speed R of the clutch input member 10 is ｉｎ It is determined whether the rotation speed R of the clutch input member 10 is greater than a predetermined threshold value T. ｉｎ can be obtained by, for example, a speed sensor provided around the clutch input member 10 or the clutch output member 11, or the motor output shaft 8. Alternatively, the rotation speed R ｉｎ can also be calculated based on the differential value of the output value of a stroke sensor for measuring the vehicle height, or the differential value of an angle sensor for measuring the rotation angle of the clutch input member 10, the clutch output member 11, or the motor output shaft 8.

[0182] In S3, the rotation speed R of the clutch input member 10 ｉｎ is equal to or less than a predetermined threshold T (R ｉｎIf it is determined that the torque control is continued, the rotational speed R of the clutch input member 10 is ｉｎ After further increasing the value, the process returns to S3.

[0183] In S3, the rotation speed R of the clutch input member 10 ｉｎ is greater than a predetermined threshold T (R ｉｎ If it is determined that the torque limit is greater than T, the process proceeds to S4, where the control mode of the motor output shaft 8 is switched from torque control to speed control or position control.

[0184] Next, in S5, it is determined whether the vehicle height is at a target value. This determination can be made based on the output signal of the stroke sensor, the rotational position of the motor output shaft 8, etc.

[0185] If it is determined in S5 that the vehicle height is not at the target value, the control to lower the vehicle height continues, and after a predetermined time has elapsed, the process returns to S5.

[0186] If it is determined in S5 that the vehicle height is equal to the target value, the process proceeds to S6, where the rotational speed of the motor output shaft 8 is reduced while the control mode of the motor output shaft 8 is maintained in the speed control or position control mode, and the rotational speed R of the clutch input member 10 is reduced. ｉｎ Reduces.

[0187] Next, in S7, the rotation speed R of the clutch input member 10 is ｉｎ is equal to or smaller than a predetermined threshold T.

[0188] In S7, the rotation speed R of the clutch input member 10 ｉｎ is determined to be greater than the predetermined threshold value T, the rotation speed R of the clutch input member 10 is further ｉｎ is decreased, and after a predetermined time has elapsed, the process returns to S7.

[0189] In S7, the rotation speed R of the clutch input member 10 ｉｎ If it is determined that the rotation speed R of the clutch input member 10 is equal to or less than the predetermined threshold value T, the process proceeds to S8. ｉｎ The target value of is set to 0. Specifically, the controller 51 instructs the electric motor 3 to stop.

[0190] In the suspension system 1 of this example, the first function rotates the motor output shaft 8 by torque control in the initial stage of the control for lowering the vehicle height, so that the rotational speed R of the clutch input member 10 is controlled as shown by the range I in FIG. ｉｎ can be quickly increased to a range of rotation speeds higher than a predetermined threshold T where jerking is unlikely to occur in the reverse input cutoff clutch 5. Therefore, it is possible to prevent the occurrence of jerking in the initial stage of control to lower the vehicle height, and to perform smooth vehicle height adjustment.

[0191] In the initial stage of the control for lowering the vehicle height, when the motor output shaft 8 is rotationally driven by speed control or position control, the rotation speed R of the clutch input member 10 increases as shown by the two-dot chain line α in FIG. ｉｎ The increase in the rotational speed R of the clutch input member 10 is slower than when the motor output shaft 8 is rotationally driven by torque control. ｉｎ However, the time spent in the rotational speed range below the threshold value T where the jerking phenomenon is likely to occur becomes longer, and the jerking phenomenon becomes more likely to occur.

[0192] Furthermore, according to the suspension system 1 of this embodiment, the second function allows the rotational speed R of the clutch input member 10 at the end stage of the control for lowering the vehicle height to be within the range indicated by E in FIG. ｉｎ During the decrease in the rotation speed R of the clutch input member 10 ｉｎ This allows the reverse input cutoff clutch 5 to quickly pass through the rotation speed range below the threshold T where jerking is likely to occur, and reduce it to zero. This makes it possible to prevent jerking from occurring when lowering the vehicle height, and allows for smooth vehicle height adjustment.

[0193] At the end of the control for lowering the vehicle height, the rotation speed R of the clutch input member 10 ｉｎ When the rotation speed R of the clutch input member 10 becomes equal to or less than the threshold value T, ｉｎ The target value of the rotation speed R of the clutch input member 10 is not set to 0. ｉｎ When the rotation speed R of the clutch input member 10 is reduced, as shown by the two-dot chain line β in FIG. ｉｎ Therefore, the rotation speed R of the clutch input member 10 decreases gradually. ｉｎHowever, the time spent in the rotational speed range below a predetermined threshold T where the jerking phenomenon is likely to occur becomes longer, and the jerking phenomenon becomes more likely to occur.

[0194] In particular, the suspension system 1 of this example uses a reverse input disconnect clutch 5 that has a configuration that allows for quick switching from an unlocked state to a locked state, and jerking is likely to occur when the rotational speed of the clutch input member 10 is in a range of rotational speeds equal to or lower than a predetermined threshold value T. For this reason, the effects of providing the first function and / or the second function are significant.

[0195] When the rotational speed of the motor output shaft 8 becomes zero and torque input to the clutch input member 10 disappears, the reverse input cutoff clutch 5 switches to a locked state and the vehicle height is maintained.

[0196] When performing vehicle height adjustment control to raise the vehicle height in a vehicle equipped with the suspension system 1 of this embodiment, the direction of the torque applied to the clutch input member 10 is opposite to the direction of the rotational torque that is reversely input to the clutch output member 11 based on the weight of the vehicle body B and occupants, the elasticity of the spring 2, etc. Therefore, when performing vehicle height adjustment control to raise the vehicle height, jerking does not occur.

[0197] (Explanation of Function for Suppressing Peak Torque of Electric Motor) The controller 51 has a function for suppressing the peak torque of the electric motor 3 .

[0198] Specifically, when rotating the clutch input member 10 to adjust the vehicle height to a desired height from a state in which the reverse input cut-off clutch 5 is locked due to a rotational torque (reverse input torque) being reversely input to the clutch output member 11, if the direction in which the clutch input member 10 should be rotated is opposite to the direction of the torque being reversely input to the clutch output member 11 (direction of the reverse input torque), the controller 51 has the function of rotating the clutch input member 10 in the direction of the reverse input torque for an extremely short, predetermined time, and then rotating the clutch input member 10 in the direction opposite to the direction of the reverse input torque.

[0199] The extremely short predetermined time is a time sufficient to switch the reverse input cutoff clutch 5 from a locked state to an unlocked state based on the rotational driving of the clutch input member 10 in the direction of the reverse input torque. Specifically, the extremely short predetermined time is preferably as short as possible within a range in which the reverse input cutoff clutch 5 can be switched from a locked state to an unlocked state based on the rotational driving of the clutch input member 10 in the direction of the reverse input torque. More specifically, the extremely short predetermined time is not limited to this, but can be 0.001 seconds or more and 0.02 seconds or less, and preferably 0.001 seconds or more and 0.01 seconds or less.

[0200] In this example, the extremely short predetermined time is a time that is sufficient to separate the pressing surface 44 from the pressed surface 33 based on the rotation of the clutch input member 10 in the direction of the reverse input torque.

[0201] In the reverse input cutoff clutch 5 of this example, in the locked state, the pressing surface 44 tends to be strongly pressed against and bite into the pressed surface 33. For this reason, when switching from the locked state to the unlocked state, it is necessary to release the pressing surface 44 from biting into the pressed surface 33.

[0202] In particular, when a rotational torque is reversely input to the clutch output member 11 and the clutch input member 10 is rotationally driven in the direction opposite to the direction of the torque reversely input to the clutch output member 11 to switch from the locked state to the unlocked state, it is necessary to release the pressing surface 44 from biting into the pressed surface 33 while resisting the force applied to the engaging element 32 in the direction that brings the pressing surface 44 closer to the pressed surface 33, based on the rotational torque reversely input to the clutch output member 11. Therefore, the magnitude of the output torque required of the electric motor 3 is greatest when a rotational torque is reversely input to the clutch output member 11 and the clutch input member 10 is rotationally driven in the direction opposite to the direction of the torque reversely input to the clutch output member 11 to switch from the locked state to the unlocked state.

[0203] Specifically, but not limited to, in the state after the reverse input cutoff clutch 5 of this example is switched to the unlocked state, the torque τ required to rotate the clutch input member 10 in the direction opposite to the direction of the torque reversely input to the clutch output member 11 is Ｒ is the torque τ required to switch the reverse input cutoff clutch 5 to the unlocked state by rotating the clutch input member 10 in the direction opposite to the direction of the torque reversely input to the clutch output member 11. ＵＮ It is between 20% and 80% of the above.

[0204] In the suspension system 1 of this example, which adjusts the vehicle height by vertically moving the spring 2 made of a coil spring, when performing control to raise the vehicle height, the direction in which the clutch input member 10 should rotate is opposite to the direction of the torque being input in reverse to the clutch output member 11.

[0205] For this reason, in the suspension system 1 of this example, when raising the vehicle height, the controller 51 rotationally drives the clutch input member 10 in the same direction as the direction of the torque that is reversely input to the clutch output member 11 based on the weight of the vehicle body and occupants, thereby separating the pressing surface 44 from the pressed surface 33, and then reverses the rotational direction of the clutch input member 10. Therefore, even when current is applied to the electric motor 3 to switch the reverse input cut-off clutch 5 from the locked state to the unlocked state in order to raise the vehicle height, it is possible to prevent the output torque required of the electric motor 3 from becoming excessive, and the electric motor 3 can be made smaller.

[0206] During the execution of control for suppressing the peak torque of the electric motor 3, the motor output shaft 8 can be controlled by speed control or position control, or can be controlled by torque control.

[0207] Second Example A second example of the embodiment of the present disclosure will be described with reference to FIGS. 11 and 12. FIG.

[0208] In the suspension system 1a of this example, the spring 2a is a rod-shaped torsion bar that generates elastic force in a torsional direction. The vehicle height adjustment mechanism 4a also includes a spring adjustment mechanism 22a that rotates the spring 2a in conjunction with the rotation of the clutch output member 11.

[0209] The spring 2a is supported by the vehicle body B so that its central axis is approximately parallel to the bottom surface of the vehicle body B and so that it can rotate around that central axis. More specifically, the spring 2a is supported on the lower part of the vehicle body B so that its central axis is oriented approximately in the width direction and so that it can rotate around that central axis.

[0210] The spring adjustment mechanism 22 a is configured by connecting and fixing the clutch output member 11 to the spring 2 a directly or via a reducer 53 .

[0211] In this example, the spring adjustment mechanism 22a is configured by connecting and fixing the clutch output member 11 to the spring 2a via a reducer 53. Specifically, an output shaft 56 of the reducer 53 is connected and fixed to the vehicle body side end 6a, which is the end on the inner side in the width direction of the spring 2a (right side in FIG. 11 ), and an input shaft 57 of the reducer 53 is connected and fixed to the clutch output member 11 of the reverse input cutoff clutch 5, or is configured integrally with the clutch output member 11. In addition, the motor output shaft 8a of the electric motor 3a is connected and fixed to the clutch input member 10 of the reverse input cutoff clutch 5, or is configured integrally with the clutch input member 10.

[0212] There is no particular limitation on the type of the reducer 53. For example, the reducer 53 can be configured as a parallel shaft gear reducer, a worm reducer, a planetary gear reducer, a belt reducer, or the like.

[0213] The vehicle height adjusting mechanism 4a further includes a lever 54 that is fixedly connected to the spring 2a and configured to move a knuckle 55 that supports the wheel W in the vertical direction as the spring 2a rotates.

[0214] The base end of the lever 54 (the end on the right side in FIG. 11 ) is fixedly connected to the wheel-side end 7 a, which is the end on the outer side in the width direction of the spring 2 a (the left side in FIG. 11 ). The tip end of the lever 54 (the end on the left side in FIG. 11 ) is supported by the knuckle 55 so as to be able to swing about a pivot point oriented substantially in the width direction.

[0215] The tip of the lever 54 is positioned at a position offset in the front-rear direction from the base end. Therefore, when the tip of the lever 54 is swung around the base end of the lever 54 by rotating the spring 2a, the knuckle 55 moves up and down. In this example, the base end portion of the lever 54 extends substantially in the front-rear direction, and the tip end portion extends outward in the width direction as it moves forward.

[0216] The knuckle 55 is supported by two arms 58a, 58b to be movable up and down relative to the vehicle body B. The upper arm 58a has its base end supported by the vehicle body B to be able to swing about a pivot axis facing approximately in the front-to-rear direction, and its tip end supported by an upper portion of the knuckle 55 to be able to swing about a pivot axis facing approximately in the front-to-rear direction. The lower arm 58b has its base end supported by the vehicle body B via the damper 12a to be able to swing about a pivot axis facing approximately in the front-to-rear direction, and its tip end supported by a lower portion of the knuckle 55 to be able to swing about a pivot axis facing approximately in the front-to-rear direction.

[0217] When implementing the suspension system and the method for controlling the suspension system according to an aspect of the present disclosure, the spring formed by the torsion bar can be supported on the vehicle body so that its central axis faces substantially in the fore-and-aft direction and is rotatable about that central axis. In this case, the arm supporting the knuckle swings about its base end as the spring rotates, thereby making it possible to adjust the vehicle height.

[0218] In addition to the spring 2a, the suspension system 1a may also include a spring 59 disposed in parallel with the damper 12a between the base end of the lower arm 58b and the vehicle body B. The suspension system 1a of this example includes the spring 59 formed of a coil spring.

[0219] In order to adjust the vehicle height in a vehicle equipped with the suspension system 1a of this example, the electric motor 3 is energized to rotate the motor output shaft 8, which rotates the spring 2a via the speed reducer 53. This causes the tip of the lever 54 to swing around the base end of the lever 54, moving the knuckle 55 up and down, thereby moving the wheel W supported by the knuckle 55 up and down relative to the vehicle body B.

[0220] In the suspension system 1 a of this example, due to an imbalance between the weight of the vehicle body B and the occupant and the elastic force of the spring 2, a force (rotational torque) that tends to rotate the clutch output member 11 is applied to the clutch output member 11.

[0221] Specifically, when the vehicle height is higher than the neutral position where the weight of the vehicle body B and occupants is balanced with the elastic force of the spring 2, the direction of the rotational torque that is reversely input to the clutch output member 11 from the wheel W side is the same as the direction in which the clutch input member 10 should be rotated to lower the vehicle height. On the other hand, when the vehicle height is lower than the neutral position, the direction of the rotational torque that is applied to the clutch output member 11 from the wheel W side is the same as the direction in which the clutch input member 10 should be rotated to raise the vehicle height. (Explanation of the function for preventing jerking in the reverse input disconnecting clutch)

[0222] In the suspension system 1 a of this embodiment, the controller 51 also has a first function and a second function for preventing jerking from occurring in the reverse input disconnecting clutch 5 .

[0223] Specifically, in the suspension system 1a of this example, when the vehicle height is adjusted in a direction that rotates the clutch input member 10 in the same direction as the direction of the rotational torque that is reversely input to the clutch output member 11, the rotational torque of the clutch input member 10 is adjusted from the start of the motor output shaft 8 to the start of the rotational torque of the clutch input member 11. ｉｎ is a predetermined first threshold T １ In the following range, the motor output shaft 8 is rotated at a rotational acceleration of the first rotational acceleration a １ and R of the clutch input member 10. ｉｎ is a predetermined first threshold T １After the rotational acceleration becomes larger than the first rotational acceleration a １ A second rotational acceleration a smaller than ２ The control is performed by speed control or position control.

[0224] However, in the suspension system 1a in this example, which adjusts the vehicle height by rotating the spring 2a formed by a torsion bar, when adjusting the vehicle height in a direction in which the clutch input member 10 rotates in the same direction as the direction of the rotational torque reversely input to the clutch output member 11, the rotational speed R of the clutch input member 10 from the start of the motor output shaft 8 is ｉｎ is less than a predetermined threshold T, the motor output shaft 8 is controlled by torque control, and the rotation speed R of the clutch input member 10 is ｉｎ From the time when the vehicle height becomes equal to or greater than a predetermined threshold value T until the end of the control for adjusting the vehicle height to the target value, the motor output shaft 8 can be controlled by speed control or position control.

[0225] Also, at the end of the control for adjusting the vehicle height, the rotation speed R of the clutch input member 10 ｉｎ When the direction of the reverse input torque and the rotation direction of the clutch input member 10 are the same, the rotation speed R of the clutch input member 10 becomes equal to or less than the predetermined threshold value T. ｉｎ Set the target value to 0.

[0226] The procedure for carrying out control to adjust the vehicle height using the suspension system 1a of this embodiment will be described with reference to the flowchart of FIG.

[0227] First, in S1, it is determined whether the direction in which the clutch input member 10 should be rotated in order to adjust the vehicle height to the desired height is the same as the direction of the rotational torque (reverse input torque) that is being reversely input to the clutch output member 11 due to an imbalance between the weight of the vehicle body B or occupant and the spring 2.

[0228] This determination can be made based on the vehicle height at that time obtained based on the output signal of the stroke sensor, the weight of the occupants and cargo obtained by a weight sensor, the operation of a switch by the driver, etc.

[0229] In S1, if it is determined that the direction in which the clutch input member 10 should be rotated is different from the direction of the reverse input torque, the process proceeds to S1-1, where the motor output shaft 8 is rotated at a second rotational acceleration a ２ After starting the vehicle height adjustment by speed control or position control, the process proceeds to S7.

[0230] If it is determined in S1 that the direction in which the clutch input member 10 should be rotationally driven is the same as the direction of the reverse input torque, the process proceeds to S2, in which the motor output shaft 8 is rotated at a first rotation acceleration a １ Start with.

[0231] Next, in S3, the rotation speed R of the clutch input member 10 is ｉｎ is greater than a predetermined threshold T.

[0232] In S3, the rotation speed R of the clutch input member 10 ｉｎ is equal to or less than a predetermined threshold T (R ｉｎ If it is determined that the rotational acceleration of the motor output shaft 8 is a １ With this, the rotation speed R of the clutch input member 10 is ｉｎ After further increasing the value, the process returns to S3.

[0233] In S3, the rotation speed R of the clutch input member 10 ｉｎ is greater than a predetermined threshold T (R ｉｎ If it is determined that the rotational acceleration of the motor output shaft 8 is a １ a smaller than ２ Switch to.

[0234] Next, in S5, it is determined whether the vehicle height is at a target value. This determination can be made based on the output signal of the stroke sensor, the rotational position of the motor output shaft 8, etc.

[0235] If it is determined in S5 that the vehicle height is not at the target value, the control for adjusting the vehicle height continues, and after a predetermined time has elapsed, the process returns to S5.

[0236] If it is determined in S5 that the vehicle height is equal to the target value, the process proceeds to S6, in which the rotational speed of the motor output shaft 8 is reduced, and the rotational speed R ｉｎ Reduces.

[0237] Next, in S7, the rotation speed R of the clutch input member 10 is ｉｎ is equal to or smaller than a predetermined threshold T.

[0238] In S7, the rotation speed R of the clutch input member 10 ｉｎ is determined to be greater than the predetermined threshold value T, the rotation speed R of the clutch input member 10 is further ｉｎ is decreased, and after a predetermined time has elapsed, the process returns to S7.

[0239] In S7, the rotation speed R of the clutch input member 10 ｉｎ If it is determined that is equal to or smaller than the predetermined threshold value T, the process proceeds to S8, where it is determined whether the rotational direction of the clutch input member 10 is the same as the direction of the rotational torque (reverse input torque) that is being reversely input to the clutch output member 11 due to an imbalance between the weight of the vehicle body B or occupant and the elastic force of the spring 2. The direction of the reverse input torque can be determined based on the vehicle height at that time, which is acquired based on the output signal of the stroke sensor, etc., and the weight of the occupant, cargo, etc., acquired by a weight sensor, etc.

[0240] In S8, if it is determined that the rotation direction of the clutch input member 10 is different from the direction of the reverse input torque, the rotation speed R ｉｎ is reduced at the same deceleration rate, and the rotation speed R of the clutch input member 10 ｉｎ After setting it to 0, the process ends.

[0241] In S8, if it is determined that the rotation direction of the clutch input member 10 is the direction of the reverse input torque, the process proceeds to S9, in which the rotation speed R ｉｎ The target value of is set to 0. Specifically, the controller 51 instructs the electric motor 3 to stop.

[0242] In the suspension system 1a of this embodiment, the first function is also used to adjust the vehicle height in a direction that rotates the clutch input member 10 in the same direction as the direction of the rotational torque that is reversely input to the clutch output member 11, by rotating the motor output shaft 8 at a first rotational acceleration a １ Therefore, the rotation speed R of the clutch input member 10 ｉｎto a range of rotation speeds higher than the predetermined threshold T where jerking is unlikely to occur in the reverse input cutoff clutch 5. Therefore, it is possible to prevent the occurrence of jerking in the initial stage of control for adjusting the vehicle height, and to perform smooth vehicle height adjustment.

[0243] Furthermore, according to the suspension system 1a of this example, when the direction of the rotational torque input in reverse to the clutch output member 11 is the same as the direction of rotation of the clutch input member 10 at the end stage of the control for adjusting the vehicle height, the second function ｉｎ This allows the reverse input cutoff clutch 5 to quickly pass through the rotation speed range below the threshold T where jerking is likely to occur, and reduce it to zero. This makes it possible to prevent jerking from occurring when lowering the vehicle height, and allows for smooth vehicle height adjustment.

[0244] (Explanation of Function for Suppressing Peak Torque of Electric Motor) In the suspension device 1 a of this embodiment, the controller 51 also has a function for suppressing the peak torque of the electric motor 3 .

[0245] In this example, when the clutch input member 10 is rotated to adjust the vehicle height to a desired height from a state in which the reverse input cut-off clutch 5 is locked due to a rotational torque (reverse input torque) being reversely input to the clutch output member 11, if the direction in which the clutch input member 10 should be rotated is opposite to the direction of the torque being reversely input to the clutch output member 11 (direction of the reverse input torque), the controller 51 has the function of driving the clutch input member 10 to rotate in the direction of the reverse input torque for an extremely short predetermined time, in this example, a time long enough to separate the pressing surface 44 from the pressed surface 33, and then rotating the clutch input member 10 in the direction opposite to the direction of the reverse input torque.

[0246] More specifically, when the vehicle height is higher than the neutral position and control is performed to raise the vehicle height, the controller 51 rotationally drives the clutch input member 10 for an extremely short time in the direction in which the vehicle height is lowered, and then rotates the clutch input member 10 in the direction in which the vehicle height is raised, thereby adjusting the vehicle height to a desired height. Also, when the vehicle height is lower than the neutral position and control is performed to lower the vehicle height, the controller 51 rotationally drives the clutch input member 10 for an extremely short time in the direction in which the vehicle height is raised, and then rotates the clutch input member 10 in the direction in which the vehicle height is lowered, thereby adjusting the vehicle height to a desired height.

[0247] In the suspension device 1a of this example, when current is applied to the electric motor 3 to switch the reverse input cut-off clutch 5 from a locked state to an unlocked state, the output torque required of the electric motor 3 can be prevented from becoming excessive, and the electric motor 3 can be made smaller.

[0248] The configuration and effects of other parts of the second example are the same as those of the first example.

[0249] REFERENCE SIGNS LIST 1, 1a Suspension device 2, 2a Spring 3, 3a Electric motor 4, 4a Vehicle height adjustment mechanism 5 Reverse input cut-off clutch 6, 6a Vehicle body side end 7, 7a Wheel side end 8, 8a Motor output shaft 10 Clutch input member 11 Clutch output member 12, 12a Damper 13 Cylinder 14 Piston 15 Cylinder space 16 Lower bracket 17 Head portion 18 Rod portion 19 Upper plate portion 20 Top mount 21 Spring seat 22, 22a Spring adjustment mechanism 23 Nut 24 Ball 25 Inner diameter side ball screw groove 26 Outer diameter side ball screw groove 27 Bearing 28 Driven side gear portion 29 Intermediate shaft 30 Driving side gear portion 31 Pressed member 32 Engagement piece 33 Pressed surface 34 Input side engagement portion 35 Base plate portion 36 Input shaft portion 37 Radial inner surface 38 Radial outer surface 39 Circumferential side surface 40 Output side engaging portion 41 Output shaft portion 42 Flat surface 43 Convex curved surface 44 Pressing surface 45 Input side engaged portion 46 Output side engaged portion 47 Flat surface 48 Concave curved surface 49 Flat surface portion 50 Convex portion 51 Controller 52 Urging member 53 Reducer 54 Lever 55 Knuckle 56 Output shaft 57 Input shaft 58a, 58b Arm 59 Spring 60 Convex groove 61 Convex portion

Claims

1. A vehicle height adjustment mechanism comprising: a spring provided to span between a vehicle body and a member supporting a wheel; an electric motor having a motor output shaft; a clutch input member that is rotationally driven based on the rotation of the motor output shaft; a reverse input cut-off clutch that has a clutch output member and that transmits the rotational torque input to the clutch input member to the clutch output member when a rotational torque is input to the clutch input member, but does not transmit the rotational torque input inversely to the clutch output member to the clutch input member when a rotational torque is input inversely to the clutch output member; and a spring adjustment mechanism that moves or rotates the spring in a vertical direction in accordance with the rotation of the clutch output member, and adjusts the vehicle height, which is the height of the vehicle body from the ground surface of the wheel, by moving or rotating the spring in a vertical direction by the spring adjustment mechanism based on the rotational driving of the motor output shaft; and a controller that controls the electric motor, wherein the controller is a first function of starting the motor output shaft at a first rotational acceleration when control is started to adjust the vehicle height in a direction to rotate the clutch input member in the same direction as the direction of the rotational torque being reversely input to the clutch output member from a state in which the reverse input cut-off clutch is locked due to a rotational torque being reversely input to the clutch output member, and switching the rotational acceleration of the motor output shaft to a second rotational acceleration lower than the first rotational acceleration when the rotational speed of the clutch input member becomes greater than a predetermined first threshold value; and a second function of setting a target value of the rotational speed of the clutch input member to 0 when the direction of the rotational torque being reversely input to the clutch output member and the rotational direction of the clutch input member are the same at a stage in which control to adjust the vehicle height is terminated and the rotational speed of the clutch input member becomes equal to or less than a predetermined second threshold value.

2. The suspension system according to claim 1, wherein the controller has the first function and is configured to control the motor output shaft by speed control or position control.

3. The suspension system of claim 1, wherein the controller has the first function and is configured to control the motor output shaft by torque control when the rotation speed of the clutch input member is in a range from the start of the motor output shaft to the predetermined first threshold value or less, and to control the motor output shaft by speed control or position control after the rotation speed of the clutch input member becomes greater than the predetermined first threshold value.

4. The reverse input cutoff clutch comprises: a pressed member having a pressed surface on its inner circumferential surface; the clutch input member having an input side engaging portion arranged radially inside the pressed surface and arranged coaxially with the pressed surface; the clutch output member having an output side engaging portion arranged radially inside the pressed surface and more radially inside than the input side engaging portion and arranged coaxially with the pressed surface; and an engager having a pressing surface facing the pressed surface, an input side engaged portion engageable with the input side engaging portion, and an output side engaged portion engageable with the output side engaging portion, and arranged to be movable in the radial direction.

4. A suspension device according to any one of claims 1 to 3, wherein when a rotational torque is input to the clutch input member, the engagement element moves radially inward based on the engagement of the input side engaging portion with the input side engaged portion, and engages the output side engaged portion with the output side engaging portion, thereby transmitting the rotational torque input to the clutch input member to the clutch output member, whereas when a rotational torque is input in reverse to the clutch output member, the output side engaging portion engages with the output side engaged portion, and the pressing surface is pressed against the pressed surface, frictionally engaging the pressing surface with the pressed surface.

5. The pressing surface is composed of two pressing surfaces, and the reverse input cut-off clutch is configured such that, when the two pressing surfaces are pressed against the pressed surface as the clutch output member rotates in a predetermined direction, and when the input side engaging portion and the input side engaged portion are engaged as the clutch input member rotates in a direction opposite to the predetermined direction, the distance between the contact portion between the input side engaging portion and the input side engaged portion and the center of rotation of the clutch input member in a second direction perpendicular to both a first direction which is the radial direction of the engager and the center of rotation of the clutch input member is greater than the distance between the contact portion between the output side engaging portion and the output side engaged portion and the center of rotation of the clutch output member in the second direction, and 5. The suspension device according to claim 4, wherein when a rotational torque is input in reverse to the clutch output member and the two pressing surfaces are in contact with the pressed surface, a contact portion between the output side engaging portion and the output side engaged portion is located closer to the center of rotation of the clutch output member in the first direction than a virtual straight line connecting a contact portion between one of the two pressing surfaces and the pressed surface and the center of rotation of the clutch output member.

6. A suspension system according to claim 4 or 5, wherein said reverse input cutoff clutch is provided with a biasing member that elastically biases said engagement element in a direction that brings said pressing surface closer to said pressed surface.

7. A suspension system according to any one of claims 1 to 6, wherein the controller has the first function and is provided with a speed sensor for measuring the number of rotations of the clutch input member, a stroke sensor for measuring the vehicle height, and / or an angle sensor for measuring the rotation angle of the clutch input member.

8. A suspension system as claimed in any one of claims 1 to 7, comprising a cylinder supported relative to the wheel, and a piston supported relative to the vehicle body and fitted in the cylinder, and further comprising a damper disposed in parallel with the spring between the vehicle body and the wheel.

9. A suspension system as described in claim 8, further comprising a spring seat supported to allow relative movement in the vertical direction with respect to the cylinder but not to allow relative rotation, the spring being constituted by a coil spring elastically sandwiched between the vehicle body and the spring seat, and the spring adjustment mechanism being configured to convert the rotational movement of the clutch output member into vertical movement of the spring seat relative to the cylinder.

10. A suspension device as described in claim 9, wherein the spring adjustment mechanism comprises a nut having an outer diameter side ball screw groove on its inner surface, which is rotationally driven based on the rotation of the clutch output member, and a plurality of balls arranged to roll between the inner diameter side ball screw groove and the outer diameter side ball screw groove provided on the outer peripheral surface of the cylinder or the outer peripheral surface of a member supported and fixed to the cylinder, and the nut is supported to allow vertical movement and relative rotation with respect to the cylinder, and to allow vertical movement integral with the spring seat.

11. A suspension device according to any one of claims 1 to 8, wherein the spring is constituted by a torsion bar, and the spring adjustment mechanism is configured to rotate the torsion bar in conjunction with rotation of the clutch output member.

12. A control method for a suspension system comprising: a spring provided to span between a vehicle body and a wheel; an electric motor having a motor output shaft; a clutch input member that is rotationally driven based on the rotation of the motor output shaft; a reverse input cut-off clutch that has a clutch output member and that transmits the rotational torque input to the clutch input member to the clutch output member when a rotational torque is input to the clutch input member, but does not transmit the rotational torque input inversely to the clutch output member to the clutch input member when a rotational torque is input inversely to the clutch output member; and a vehicle height adjustment mechanism that moves or rotates the spring in a vertical direction in accordance with the rotation of the clutch output member, and adjusts the vehicle height, which is the height of the vehicle body from the ground surface of the wheels, by moving or rotating the spring in a vertical direction using the spring adjustment mechanism based on the rotational driving of the motor output shaft, A method for controlling a suspension system, when starting control to adjust the vehicle height in a direction to rotate the clutch input member in the same direction as the direction of the rotational torque being reversely input to the clutch output member from a state in which the reverse input cut-off clutch is locked due to a rotational torque being reversely input to the clutch output member, the method includes starting the motor output shaft at a first rotational acceleration, and switching the rotational acceleration of the motor output shaft to a second rotational acceleration smaller than the first rotational acceleration when the rotational speed of the clutch input member becomes greater than a predetermined first threshold value.

13. The method for controlling a suspension system according to claim 12, wherein the motor output shaft is controlled by speed control or position control.

14. A method for controlling a suspension system as described in claim 12, wherein, when the rotational speed of the clutch input member is in a range from the start of the motor output shaft to the predetermined first threshold value or less, the motor output shaft is controlled by torque control, and, after the rotational speed of the clutch input member becomes greater than the predetermined first threshold value, the motor output shaft is controlled by speed control or position control.

15. A control method for a suspension system comprising: a spring provided to span between a vehicle body and a member supporting a wheel; an electric motor having a motor output shaft; a clutch input member that is rotationally driven based on the rotation of the motor output shaft; a reverse input cut-off clutch that has a clutch output member, and when a rotational torque is input to the clutch input member, transmits the rotational torque input to the clutch input member to the clutch output member, but when a rotational torque is reversely input to the clutch output member, does not transmit the rotational torque reversely input to the clutch output member to the clutch input member; and a height adjustment mechanism that moves or rotates the spring in a vertical direction in accordance with the rotation of the clutch output member, and adjusts the vehicle height, which is the height of the vehicle body from the ground surface of the wheel, by moving or rotating the spring in a vertical direction using the spring adjustment mechanism based on the rotational driving of the motor output shaft, A control method for a suspension system, comprising: setting a target value of the rotational speed of the clutch input member to 0 when the direction of the rotational torque being reversely input to the clutch output member is the same as the rotational direction of the clutch input member at a stage at which control to adjust the vehicle height is completed and the rotational speed of the clutch input member becomes equal to or lower than a predetermined second threshold value.

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