Damping device

Abstract

To provide an attenuation device that is excellent in mountability and attenuation responsiveness.SOLUTION: An attenuation device S is used in a suspension which comprises an arm 2 whose one end part is oscillatably supported on a vehicle and whose other end part supports a wheel of the vehicle and an operation member D provided across the vehicle and the arm 2 so as to hold the arm 2 in an oscillating posture with respect to the vehicle, where the operation member D comprises a rotation part R that takes out, as rotation motion, a state variation thereof. The device comprises a braking part B1 that controls the state variation of the arm 2 by suppressing rotation of the rotation part R.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a damping device for a suspension, for example, in which an arm extending in the longitudinal direction of a vehicle to support a wheel is swingably supported by a subframe.

Background Art

[0002] Conventionally, as such a damping device, there is, for example, one shown in Patent Document 1 (see

[0011] ,

[0018] to

[0019] and FIG. 1).

[0003] This damping device includes a pair of trailing arms that extend in the longitudinal direction on both sides of the vehicle, have a swing fulcrum provided at the front, and support a wheel at the rear end, and a torsion beam that extends in the vehicle width direction and connects the pair of trailing arms. Further, a hydraulic strut damper that expands and contracts during wheel stroke is connected to the trailing arm.

[0004] In particular, in this damping device, the strut damper is not arranged inside the wheel as in the conventional case, but is located on the front side of the vehicle with respect to the trailing arm and is arranged along the longitudinal direction of the vehicle.

[0005] According to this structure, a suspension can be configured without arranging the strut damper inside the vehicle of the wheel. For this reason, it is not necessary to provide a rotary damper or the like at the front end of the trailing arm, and it is possible to widely reduce the floor height in the vehicle width direction with respect to the passenger compartment or the cargo compartment, and it is said that the living space can be expanded.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the conventional damping devices described above, a common stroke-type damper is used as the damping mechanism for the suspension. This mechanism obtains damping force through flow resistance caused by changes in the volume of the piston and cylinder in order to absorb the vertical stroke of the wheel. Therefore, the overall length is increased and the mounting location is limited, so it is often mounted relatively close to the wheel, and there are limitations to the degree of freedom in mounting.

[0008] Furthermore, for the damper to exert its damping effect, the control fluid needs to flow through the oil passages of the cylinder, but due to structural limitations, the damping effect cannot be arbitrarily changed.

[0009] Thus, conventional technologies have various issues that need to be addressed, and there was a need for a damping device that is easy to install and has excellent damping response. [Means for solving the problem]

[0010] (Feature composition) The characteristic configuration of the damping device according to the present invention is: An arm having one end that is pivotally supported by the vehicle and the other end that supports the wheel of the vehicle, Used in a suspension system comprising: an operating member provided across the vehicle and the arm to maintain the swinging position of the arm relative to the vehicle; The operating member A rotating part that extracts state changes as rotational motion. and, The rotation of the rotating part is suppressed to control the change in the posture of the arm. To that end, a braking unit having a friction plate that rotates in conjunction with the rotation of the rotating unit and a pressing plate that acts on the friction plate, The system includes a braking drive unit that brings the pressing plate into contact with the friction plate, The braking drive unit includes a tension member that pulls the pressing plate when pressing the pressing plate against the friction plate. It's at a single point.

[0011] (effect) Conventionally, for the damping device of the arm constituting the suspension, for example, a hydraulic control type oil damper or the like has been used. In this case, a predetermined time is required for the supply and discharge of the working oil, and the responsiveness related to the attitude control of the arm is not sufficient. Therefore, in this configuration, by suppressing the rotation of the operating member that holds the swinging attitude of the arm by the braking unit, excessive swinging of the arm can be suppressed, and the attitude of the suspension can be controlled to an appropriate state.

[0012]

[0013] The configuration of generating friction by applying the pressing plate to the friction plate in this way is relatively simple. Also, since these shapes are simple, it is easy to set the force for pressing the pressing plate against the friction plate, and the size and material of the friction plate can also be set appropriately. Therefore, a reasonable and low-cost damping device can be obtained.

[0014]

[0015] In this configuration, a braking drive unit that acts on the pressing plate is provided, and the pressing plate can be positively brought into contact with the friction plate. By providing this braking drive unit, the swinging of the arm can be braked at an appropriate timing, and an optimal damping effect can be exhibited according to the running state of the vehicle. Furthermore, in the damping device according to the present invention, the braking drive unit is equipped with a tensioning member that pulls the pressing plate when pressing the pressing plate against the friction plate. When pressing the pressure plate against the friction plate with a predetermined force, the driving force generated in the braking drive unit is transmitted to the pressure plate. A component is needed to reach the target. This transmission component must be able to be installed in a confined space, taking mounting requirements into consideration. This is preferable. To achieve this, the tensile member should be designed to be less prone to buckling, thereby reducing the size of the part. This allows for miniaturization and weight reduction, while enabling the creation of a braking drive unit capable of generating significant driving force.

[0016] (Characteristic configuration) In the damping device according to the present invention, it is convenient to provide a correlation between the swinging speed of the arm and the operating force applied by the braking drive unit to the friction plate. It is convenient to provide a correlation between the swinging speed of the arm and the operating force applied by the braking drive unit to the friction plate.

[0017] (Effect) With this configuration, for example, when the wheel quickly moves up and down and the swinging speed of the arm is high, the friction plate It is strongly pressed, enhancing the effect of suppressing the rotation of the arm. Specifically, when driving on a road surface with many unevennesses, excessive rotation of the arm is suppressed, and the suspension setting becomes what is called a firm one. Also, when the vehicle is cornering at high speed, the front outer wheel rises significantly with respect to the vehicle, but this movement is also suppressed, and the turning posture of the vehicle becomes stable. Thus, providing the braking drive unit makes it easy to set the driving characteristics of the vehicle.

[0018]

[0019]

[0020] (Characteristic configuration) In the damping device according to the present invention, the operating member is a rod-shaped torsion spring arranged coaxially with the rotation axis of the arm, the rotating portion is the end of the torsion spring, and it is convenient that the friction plate and the rotating portion are provided coaxially.

[0021] (Effect) As the shape of the braking portion, for example, an annular plate member, a member in which a shaft member protrudes from the center of a disc-shaped plate member, or various shapes can be adopted. In that case, if the rotation axis of the friction plate of the braking portion is coaxial with the rotation axes of the torsion spring and the arm, it becomes easy to grasp the relationship between the swinging speed of the arm and the rotation speed of the braking portion, and it becomes easy to set the braking force applied to the braking portion. Also, it becomes easy to construct a structure for coordinating the braking portion and the torsion spring, and a simple and compact damping device can be obtained.

[0022] (Characteristic configuration) In the damping device according to the present invention, an amplifying portion for amplifying the rotation angle of the swinging axis and transmitting it to the braking portion can be provided between the swinging axis of the arm and the braking portion. ​​​​​

[0023] (effect) The angle at which the suspension arms swing as the wheels move up and down is not very large. Therefore, the amount of displacement on the surface of the arm is extremely small, and such arm displacement is directly It is difficult to apply braking directly. Therefore, in this configuration, an amplification unit is provided to increase the rotation angle of the arm, and the displacement amount of the braking unit is increased. This configuration makes it easy to set the braking force.

[0024] (Feature composition) In the damping device according to the present invention, a vehicle height control motor is attached to the amplification unit, and the vehicle The drive shaft of the high-control motor is configured to rotate in conjunction with the rotation of the pivot shaft. That would be convenient.

[0025] (effect) By incorporating a vehicle height control motor in this configuration, even slight swing angles of the arm are amplified via the amplification unit. The amplified signal allows for clear rotation of the drive shaft of the vehicle height control motor. High-performance motors can be used, for example, as regenerative devices, to obtain high-value-added damping devices. It is possible.

[0026] On the other hand, when the motor for vehicle height control is actively driven, the rotational speed of the drive shaft is amplified by the amplification unit. The force is decelerated and transmitted to the arm. This enables the suspension to function as an active suspension. It can be used to add a ride height adjustment function to the suspension. (Feature composition) The damping device according to the present invention is Used in a suspension comprising: an arm, one end of which is pivotally supported by a vehicle and the other end of which supports the wheel of the vehicle; and a moving member provided across the vehicle and the arm to maintain the pivoting position of the arm relative to the vehicle; A rotating unit that extracts the state change of the aforementioned operating member as a rotational movement, A braking unit that suppresses the rotation of the rotating part and controls the change in the posture of the arm, The system includes an amplification unit provided between the pivot axis of the arm and the braking unit, which amplifies the rotation angle of the pivot axis and transmits it to the braking unit. A motor for controlling the vehicle height can be attached to the amplification unit, and the drive shaft of the vehicle height control motor can be configured to rotate in conjunction with the rotation of the oscillating shaft. (effect) In this configuration, an amplification unit is provided between the arm's pivot axis and the braking unit to amplify the rotation angle of the pivot axis and transmit it to the braking unit, and a vehicle height control motor is installed in the amplification unit. As a result, even a slight pivot angle of the arm is amplified via the amplification unit, allowing the drive shaft of the vehicle height control motor to rotate clearly, and thus the vehicle height control motor can be used, for example, as a regenerative braking device. On the other hand, the amplification unit also functions as a reduction unit that transmits the rotational drive of the vehicle height motor to the pivot axis of the arm while reducing its speed. Therefore, by actively driving the vehicle height control motor, the suspension can be made into an active suspension. [Brief explanation of the drawing]

[0027] [Figure 1] Perspective view showing the configuration of the damping device according to the first embodiment. [Figure 2] Cross-sectional view showing the structure of the damping device according to the first embodiment. [Figure 3] Cross-sectional view showing the structure of the damping device according to the second embodiment. [Figure 4] Cross-sectional view showing the structure of the damping device according to the third embodiment. [Modes for carrying out the invention]

[0028] 〔overview〕 The damping device S according to the present invention is used, for example, in the suspension of a vehicle 1, which includes a suspension arm 2 (hereinafter referred to as "arm 2") that extends in the longitudinal direction of the vehicle 1, with one end being pivotally supported by the vehicle 1 and the other end supporting the wheel of the vehicle 1, and an operating member D provided across the vehicle 1 and the arm 2 to maintain the pivoting posture of the arm 2 relative to the vehicle 1.

[0029] In this embodiment, the operating member D is the pivot shaft 2a of the arm 2, which is driven when the arm 2 swings. In this embodiment, the suspension damping is achieved by utilizing various rotating parts R, such as the pivot shaft 2a, which rotates due to the swinging of the arm 2.

[0030] [First embodiment of the damping device] Figure 1 shows the external appearance of a damping device S equipped with a torsion spring 3 as a first embodiment, and Figure 2 shows its internal structure.

[0031] As shown in Figure 1, the vehicle 1 has subframes 5 that extend laterally from the left and right front and rear wheels, and arms 2 that support the wheels are pivotally supported on these subframes 5. The subframes 5 are provided with fixing parts 7, for example, which have bolt holes 7a, for attachment to the vehicle 1.

[0032] The subframe 5 is equipped with a torsion spring 3, which stabilizes the vertical movement of the wheels during travel through its elastic force. As shown in Figure 2, the torsion spring 3 is enclosed within the cylindrical oscillating shaft 2a of the arm 2, with one end fixed to the subframe 5 and the other end fixed to the inner surface of the oscillating shaft 2a. As a result, when the arm 2 oscillates up and down, the torsion spring 3 fixed to the inner surface of the oscillating shaft 2a applies a biasing force to the arm 2, functioning to return the arm 2 to its desired position.

[0033] (Amplification section) To optimally control the swing angle of arm 2, or to reliably stop excessive swinging of arm 2, the absolute value of the angle change of the swing axis 2a is extremely small. Therefore, to amplify the rotation angle of the swing axis 2a and facilitate control, an amplification unit Z is connected to the swing axis 2a of arm 2. In this case, the swing axis 2a of arm 2 becomes the operating member D, and one end of the swing axis 2a becomes the rotating unit R that extracts the rotational motion.

[0034] The amplification unit Z is housed within a housing 6 fixed to the subframe 5. The fixing of the amplification unit Z to the subframe 5 mutually enhances the strength of both the housing 6 and the subframe 5. Furthermore, the material thickness of the housing 6 and subframe 5 can be reduced, resulting in a more rational damping device S with reduced overall dimensions and weight.

[0035] The amplification unit Z is composed of a gear train, for example, using a planetary gear mechanism. The input shaft Z1 is engaged with the pivot axis 2a of the arm 2. This input shaft Z1 corresponds to the boss portion of the internally toothed first ring gear gr1. Furthermore, the outer surface of this input shaft Z1 is pivotally supported by the housing 6 via a bearing 9, and the inner surface of the input shaft Z1 pivotally supports the carrier C, which will be described later.

[0036] Multiple planetary gears gp are pivotally supported on carrier C. Each planetary gear gp has a two-stage configuration consisting of a first gear gp1 and a second gear gp2. The first gear gp1 meshes with the first ring gear gr1. The second gear gp2 meshes with the second ring gear gr2, which has internal teeth on its outer side. The second ring gear gr2 is fixed to housing 6.

[0037] The output shaft Z2, which will be connected to the braking section B1 described later, is meshed with the inside of the second gear gp2. The output shaft Z2 functions as a sun gear gs, and a portion of its outer surface is pivotally supported by the housing 6 via a bearing 9. In addition, the other portion of the outer surface of the output shaft Z2 is pivotally supported by the end of the carrier C opposite to the input shaft Z1 via a bearing 9.

[0038] In this configuration, as the input shaft Z1 rotates, the first gear gp1 rotates in the same direction as the input shaft Z1 via the first ring gear gr1. The second gear gp2 is meshed with the fixed second ring gear gr2, causing the carrier C to rotate in the opposite direction to the rotation of the input shaft Z1. Furthermore, as the second gear gp2 rotates, the output shaft Z2, which is the sun gear g, rotates in the opposite direction to the input shaft Z1. By using this planetary gear mechanism and appropriately setting the number of teeth on each gear, the rotational speed of the output shaft Z2 can be increased relative to the rotational speed of the input shaft Z1.

[0039] Furthermore, depending on the suspension configuration, the amplification unit Z may be omitted. For example, even if the swing angle of arm 2 is small, if a large-diameter braking member is provided at the end of arm 2, and the desired deceleration control can be achieved by braking the end of the braking member, the amplification unit Z can be omitted.

[0040] (braking part) The output shaft Z2, whose rotational speed has increased, is reduced to a predetermined rotational speed by the braking unit B1, thereby controlling the change in the posture of the arm 2. The braking unit B1 comprises a cup-shaped body b11 that rotates integrally with the output shaft Z2. Inside the cylindrical wall of the body b11, a plurality of annular friction plates b13 are arranged in a line along the extension direction of the output shaft Z2. Two types of friction plates b13 are provided; for example, each has at least one notch on its outer edge, and this notch engages with an outer protrusion b14 formed on the inner surface of the cylindrical wall of the body b11 along the extension direction of the output shaft Z2. As a result, the friction plates b13 rotate in conjunction with the body b11 and are movable relative to the body b11 along the extension direction of the output shaft Z2.

[0041] The other friction plate b13 has at least one notch on its inner circumference, which engages with an inner protrusion 63 on the surface of a boss portion 62 that protrudes from the bottom 61 of the housing 6. As a result, the other friction plate b13 does not rotate relative to the housing 6, but can move along the extension direction of the output shaft Z2. With this configuration, the rotational speed of the friction plate b13 of the braking unit B1 becomes appropriately large, making it easy to adjust the braking force generated by the braking drive unit B2 described later.

[0042] (Braking drive unit) These friction plates b13 are braked by the braking drive unit B2. A disc-shaped pressure plate b21 abuts against the friction plate b13 closest to the output shaft Z2. The pressure plate b21 has an annular pressurizing portion that presses multiple friction plates b13 together to generate frictional force. A female threaded portion b21b is formed on the inner surface of a boss portion b21a located in the center of the pressure plate b21, and is provided along the extension direction of the output shaft Z2.

[0043] On the other hand, at least one protrusion b21c is formed on the outer surface of the boss portion b21a, along the extension direction of the output shaft Z2. This protrusion b21c engages with a groove 64 formed on the inner surface of the boss portion 62 of the housing 6, allowing the pressing plate b21 to move along the extension direction of the output shaft Z2 without rotating.

[0044] A rod-shaped tension member b22 is screwed into the female threaded portion b21b of the pressing plate b21. The tension member b22 has a male threaded portion at one end that screws into the female threaded portion b21b of the pressing plate b21, and the other end engages with the drive shaft Ma of the motor M described later. Furthermore, a flange portion b22a is provided at the other end, and this flange portion b22a is sandwiched between a stepped portion 65 formed on the inner surface of the boss portion 62 and the end face of the motor M, thereby restricting movement along the output shaft Z2.

[0045] By using these components and switching the rotation direction of the motor M, the tension member b22 can be moved along the rotation axis X, thereby increasing or decreasing the pressing force between the friction plates b13. This sets the output shaft Z2 of the amplification unit Z to either a braking state or a release state. Furthermore, by using the tension member b22, there is no concern about buckling, and a braking drive unit B2 can be obtained that can generate a large driving force while reducing the size and weight of the components.

[0046] By equipping the braking drive unit B2 with an electric motor M in this way, the oscillation of the arm 2 that needs to be suppressed can be quickly and reliably suppressed at the appropriate timing, and the posture of the suspension can be controlled to an appropriate state according to the driving conditions of the vehicle 1.

[0047] The configuration described above, which includes a friction plate b13, is relatively simple. Therefore, it becomes easy to set the pressing force applied to the friction plate b13, and the size and material of the friction plate b13 can also be set as appropriate.

[0048] Furthermore, if the rotation axis of the braking unit B1 is coaxial with the oscillation axis of the arm 2, it becomes easier to understand the relationship between the oscillation speed of the arm 2 and the rotation speed of the braking unit B1, making it easier to set the braking force applied to the braking unit B1. In addition, it becomes easier to construct a structure that links the braking unit B1 with the torsion spring 3, resulting in a simple, compact, and low-cost damping device S.

[0049] The operation of the tension member b22 by the braking drive unit B2 is performed, for example, based on a correlation between the swing speed of the arm 2 and the operating force applied by the braking drive unit B2 to the friction plate b13. The swing speed of the arm 2 can be determined, for example, by detecting the value detected by the vehicle height sensor 8 attached to the vehicle 1, or the rotation speed of any rotating member of the amplification unit Z that rotates driven by the arm 2. For the vehicle height sensor 8, for example, a link-type sensor installed across the arm 2 and the vehicle 1, or a G sensor that detects vertical acceleration, may be used.

[0050] The operating force applied to the friction plate b13 can be determined, for example, by detecting the rotation angle and rotational load of the drive shaft Ma of the motor M. It is advisable to pre-establish a correlation between the swing speed of the arm 2 and the operating force applied to the friction plate b13 by the braking drive unit B2, and store this relationship in the control unit ECU.

[0051] With this configuration, for example, when vehicle 1 travels on an uneven road surface and the swing speed of arm 2 increases, the friction plate b13 is strongly pressed, enhancing the rotation suppression effect of arm 2 and reducing suspension flutter. Also, when vehicle 1 turns at high speed, the outer front part of vehicle 1 may sink significantly, but this movement is also suppressed, stabilizing the turning posture of vehicle 1. In this way, providing the braking drive unit B2 makes it easy to improve the driving characteristics of vehicle 1.

[0052] [Second embodiment of the damping device] Figure 3 shows a second embodiment of the damping device S. In this embodiment, the damping device S is provided with a locking part L that engages with a part of the amplification unit Z, instead of the friction plate b13 described above. Specifically, a plate-shaped locking plate 10 is connected to the shaft end of the sun gear g of the amplification unit Z so as to rotate integrally with it, and a plate-shaped locking plate 11 is configured to engage with and disengage from this locking plate 10 along the rotation axis X.

[0053] The locking plate 10 and the locking plate 11 each have claw portions 12 and holes 13 that engage with each other. These are locked and unlocked by a solenoid 15 pushing and pulling an operating shaft 14 located at the center of the locking plate 11. The solenoid 15 operates according to instructions from the control unit (ECU) in accordance with the driving state of the vehicle 1.

[0054] At least one notch 11a is provided on the outer circumference of the locking plate 11, which engages with a protrusion 66 formed on the inner surface of the housing 6 along the rotation axis X. As a result, the locking plate 11 reciprocates without rotating relative to the housing 6. Although not shown in Figure 3, a biasing member may be provided to engage the claw portion 12 and the hole portion 13, or to separate them, when the solenoid 15 is not energized.

[0055] The shapes of the claw portion 12 and the hole portion 13 are arbitrary. For example, various shapes such as a rectangular parallelepiped, a triangular prism, or a semi-cylindrical shape can be adopted. If the shape is a rectangular parallelepiped, even if a rotational force is applied to the locked plate 10 while the two are locked, the locked state of the two will not be easily released. On the other hand, if the surfaces involved in the locking of the two, such as a triangular prism shape, are at an angle with respect to the rotation direction of the locked plate 10, the locked state of the two will be easily released by a reverse input acting on the locked plate 10. In other words, by considering the force that causes the locked plate 10 to rotate due to the reverse input from the arm 2 and the pressing force between the claw portion 12 and the hole portion 13 by the solenoid 15, it is possible to arbitrarily select a shape that prevents the two from being unexpectedly released.

[0056] In this configuration, when the claw portion 12 and the hole portion 13 are not engaged and the vehicle 1 is stationary, the amplification unit Z and the torsion spring 3 are in their basic state. In other words, this is when the vehicle 1 is in the so-called 1G state. When the claw portion 12 and the hole portion 13 are engaged in this state, the torsion spring 3 is locked in its basic state. When the vehicle 1 is driven in this state, the vehicle height of the vehicle 1 is less likely to fluctuate, and the torsion spring 3 performs a damping function while enhancing the vehicle height maintenance effect.

[0057] On the other hand, when the vehicle 1 is traveling on rough roads, the solenoid 15 is operated to disengage the claw portion 12 and the hole portion 13, allowing the torsion spring 3 to rotate significantly relative to the vehicle 1. In this way, the damping device S can appropriately adjust the driving characteristics of the vehicle 1 despite its simple configuration.

[0058] Providing the locking plate 10 and locking plate 11 as in this configuration is relatively simple, does not impose any structural problems, and allows for a compact device configuration. Therefore, a highly reliable vehicle height maintenance function can be easily added to a suspension equipped with a torsion spring 3 and an arm 2.

[0059] [Third embodiment of the damping device] As shown in Figure 4, the damping device S shown in the first embodiment may be further modified by adding a vehicle height control motor M2 (hereinafter referred to as "vehicle height motor M2") between the amplification unit Z and the braking unit B1. In this case, the amplification unit Z also functions as a reduction unit G that transmits the rotational drive of the vehicle height motor M2 to the pivot axis 2a of the arm 2 while reducing its speed. The vehicle height motor M2 is driven by a drive signal from a control unit ECU separately provided in the vehicle 1.

[0060] (Vehicle height motor) The vehicle height motor M2 is, for example, a DC brushless motor powered by a 12V battery. The drive shaft M2a of the vehicle height motor M2 is arranged coaxially with the oscillating shaft 2a, resulting in a compact configuration relative to the subframe 5. There are no particular restrictions on the type of vehicle height motor M2, but one that can count rotational speed, for example, is advantageous because it allows for the determination of the oscillating angle of the arm 2. Using the vehicle height motor M2 provides extremely high responsiveness in lifting and lowering control, enabling rapid lifting and lowering of the wheels.

[0061] (reduction part) The angle at which arm 2 swings is small compared to the amount of rotation of the vehicle height motor M2. Therefore, in order to properly transmit the drive rotation from the vehicle height motor M2 to arm 2, it is necessary to reduce the rotational speed using a reduction unit G or the like. Here, the amplification unit Z shown in the first embodiment functions as a reduction unit G. As for the reduction effect, by appropriately adjusting the number of teeth of each component gear, the rotational speed of the drive shaft M2a is reduced to, for example, about 1 / 10,000th. In other words, the vehicle height motor M2 can be rotated at a relatively fast predetermined speed, and arm 2 can be precisely swung by the small swing angle required for vehicle height adjustment.

[0062] In this embodiment, when there is a reverse input from arm 2, the drive shaft M2a of the ride height motor M2, which rotates amplified via the oscillating shaft 2a and reduction unit G, is utilized. The cup-shaped body b11 of the braking unit B1 is connected to the drive shaft M2a. In this way, the damping device S of arm 2 can be added to a ride height control device equipped with a ride height motor M2, making it possible to obtain a ride height control device with superior functionality.

[0063] [Other embodiments of damping devices] In addition to the planetary gear mechanism shown in Figure 1, the amplification section Z of the damping device S can also use a harmonic drive gear mechanism (not shown) which has a large rotational speed conversion ratio. Even with a harmonic drive gear mechanism, it can be arranged coaxially with the arm 2 on the subframe 5, resulting in a compact damping device S.

[0064] In the example shown in Figure 2, the friction plate b13 is braked by the motor M, but instead, various biasing members may be used to press the friction plates b13 against each other, thereby generating a constant frictional force. In this case, the friction plates b13 rotate relative to each other when the arm 2 moves up and down, but the frictional force between the friction plates b13 suppresses the swinging of the arm 2 to a predetermined range.

[0065] The amplification unit Z and the braking unit B1 do not necessarily have to be arranged coaxially with the arm 2 and the torsion spring 3; the arm 2 and the amplification unit Z may mesh with spur gears or the like. Also, the housing 6 that houses the amplification unit Z and the braking unit B1 may be attached to the vehicle 1 rather than the subframe 5.

[0066] In a suspension system that stabilizes the posture of arm 2 by providing a coil spring between arm 2 and vehicle 1, for example, a rack and pinion that mesh with each other are arranged on both arm 2 and vehicle 1. This pinion may also serve as a rotating part R, and a friction plate b13 that rotates integrally with the pinion may be used to brake it.

[0067] The extension direction of arm 2 is generally in the longitudinal direction of vehicle 1. However, depending on the vehicle configuration, arm 2 may extend in a direction inclined by a predetermined angle with respect to the longitudinal direction of vehicle 1, or it may extend in the lateral direction of vehicle 1. [Industrial applicability]

[0068] The damping device of the present invention can be widely used in vehicles having a suspension in which an arm supporting a wheel is attached via a pivot axis. [Explanation of Symbols]

[0069] 1 vehicle 2 Arms 2a Arm pivot axis 3 Torsional spring B1 Braking part b13 Friction plate B2 Braking and drive unit b21 Pressure plate b22 Tension member D Operating Member M2 Motor for Vehicle Height Control M2a drive shaft R Rotating part S Damping Device X Rotation axis Z amplification section

Claims

1. An arm having one end that is pivotally supported by the vehicle and the other end that supports the wheel of the vehicle, Used in a suspension system comprising: an operating member provided across the vehicle and the arm to maintain the swinging position of the arm relative to the vehicle; A rotating unit that extracts the state change of the aforementioned operating member as a rotational movement, A braking unit having a friction plate that rotates in conjunction with the rotation of the rotating unit and a pressing plate that acts on the friction plate, in order to suppress the rotation of the rotating unit and control the change in the posture of the arm, The system includes a braking drive unit that brings the pressing plate into contact with the friction plate, A damping device comprising a tension member that pulls the pressing plate when the braking drive unit presses the pressing plate against the friction plate.

2. The damping device according to claim 1, wherein a correlation is provided between the swinging speed of the arm and the operating force applied by the braking drive unit to the friction plate.

3. The damping device according to claim 1 or claim 2, wherein the operating member is a rod-shaped torsion spring arranged coaxially with the rotation axis of the arm, the rotating portion is the end of the torsion spring, and the friction plate and the rotating portion are provided coaxially.

4. The damping device according to any one of claims 1 to 3, wherein an amplification unit is provided between the pivot axis of the arm and the braking unit for amplifying the rotation angle of the pivot axis and transmitting it to the braking unit.

5. The damping device according to claim 4, wherein a vehicle height control motor is attached to the amplification unit, and the drive shaft of the vehicle height control motor is configured to rotate in conjunction with the rotation of the oscillating shaft.

6. Used in a suspension comprising: an arm, one end of which is pivotally supported by a vehicle and the other end of which supports a wheel of the vehicle; and a moving member provided across the vehicle and the arm to maintain the pivoting position of the arm relative to the vehicle, A rotating unit that extracts the state change of the aforementioned operating member as a rotational movement, A braking unit that suppresses the rotation of the rotating part and controls the change in the posture of the arm, The system includes an amplification unit provided between the pivot axis of the arm and the braking unit, which amplifies the rotation angle of the pivot axis and transmits it to the braking unit. A damping device is provided in which a vehicle height control motor is attached to the amplification unit, and the drive shaft of the vehicle height control motor is configured to rotate in conjunction with the rotation of the oscillating shaft.

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