Suspension device and vehicle

Abstract

A suspension device according to the present invention comprises: a link member that is connected between a vehicle body structure and a suspension arm providing suspension for a wheel, includes a first coupling point coupled to the vehicle body structure side, a second coupling point coupled to the suspension arm side, and a third coupling point coupled to a damper for absorbing impact transmitted to the wheel, and rotates around a prescribed rotation axis; and an actuator that is provided between the first coupling point and the vehicle body structure and rotates the link member around the prescribed rotation axis. The link member is rotated in a first direction, thereby changing the position of the second coupling point to increase the negative camber of the wheel, and changing the position of the third coupling point to increase the vehicle height. The link member is rotated in a second direction opposite the first direction, thereby changing the position of the second coupling point to reduce the negative camber of the wheel, and changing the position of the third coupling point to reduce the vehicle height.

Description

Suspension device and vehicle

[0001] The present disclosure relates to a suspension device and a vehicle.

[0002] A suspension device for a vehicle such as an automobile connects a hub bearing housing (hereinafter simply referred to as "housing"), which rotatably supports a wheel, to the vehicle body via multiple arms, and suspends the housing in a state in which it can move relative to the vehicle body by swinging each arm.

[0003] For example, Patent Document 1 proposes a suspension device that facilitates vehicle height adjustment. Specifically, Patent Document 1 discloses a suspension device in which an upper or lower part of a wheel support member that supports a wheel is connected to a vehicle body member by a lower arm and an upper arm that extend in the vehicle width direction, and at least one of the lower arm and the upper arm is made of an elastic member having a predetermined bending rigidity, and the arm made of the elastic member is journaled to the vehicle body member so as to be rotatable in the up-down direction about an axis that extends approximately in the fore-and-aft direction of the vehicle, and includes an arm main body that is integral with the journal portion and extends approximately in the vehicle width direction and is connected to the wheel support member, and a raised portion that is integral with the journal portion and extends approximately in the up-down direction of the vehicle, and the raised portion is connected to the vehicle body member via a connecting member that extends approximately in the vehicle width direction.

[0004] Furthermore, Patent Document 2 discloses a suspension device that can change the camber angle of the wheels depending on the driving state of the vehicle. Specifically, Patent Document 2 proposes a suspension device in which, when the vehicle pitches or bounces while traveling in a straight line, the forces acting on the rocker links on both sides are balanced on the left and right sides of the vehicle body, so that these rocker links are held in a neutral position relative to the vehicle body, and the upper arms on both sides of the vehicle body stroke up and down symmetrically around axes on the rocker links, and when the vehicle body rolls due to centrifugal force during cornering, the rocker links rotate around the axis almost integrally with the upper arms, changing the camber angle of the wheel on the outside of the turn in a negative direction.

[0005] JP 7-304313 A JP 2015-134555 A

[0006] However, in the suspension device described in Patent Document 1, the camber angle of the wheel changes in a positive direction when the vehicle height is increased. Therefore, for example, when the vehicle height of the outer wheel side is increased to reduce rolling while the vehicle is turning, the camber angle of the wheel changes in a positive direction, which may reduce driving stability.

[0007] Furthermore, although the suspension device described in Patent Document 2 has a configuration in which the camber angle changes in a negative direction when the vehicle height increases, the left and right suspensions are linked to maintain the stability of the vehicle body during pitch, bounce, and cornering, and cannot be adjusted for each wheel.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide a suspension device and a vehicle that can appropriately set the camber angle of the wheels in accordance with changes in vehicle height.

[0009] In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided a suspension device comprising: a link member connected between a suspension arm that suspends a wheel and a vehicle body structure, the link member having a first connection point connected to the vehicle body structure, a second connection point connected to the suspension arm, and a third connection point connected to a damper that absorbs impacts transmitted to the wheel, the link member rotating around a predetermined rotation axis; and an actuator provided between the first connection point and the vehicle body structure, which rotates the link member around the predetermined rotation axis, wherein by rotating the link member in a first direction by the actuator, the position of the second connection point changes, thereby increasing the negative camber of the wheel and the position of the third connection point changes, thereby increasing the vehicle height; and by rotating the link member in a second direction opposite to the first direction by the actuator, the position of the second connection point changes, thereby decreasing the negative camber of the wheel and the position of the third connection point changes, thereby decreasing the vehicle height.

[0010] In order to solve the above-mentioned problems, according to another aspect of the present disclosure, there is provided a vehicle including a suspension device that suspends a wheel, wherein the suspension device comprises: a link member connected between a suspension arm that suspends the wheel and a vehicle body structure, the link member having a first connection point that is connected to the vehicle body structure, a second connection point that is connected to the suspension arm, and a third connection point that is connected to a damper that absorbs impacts transmitted to the wheel, the link member rotating around a predetermined rotation axis; and an actuator provided between the first connection point and the vehicle body structure, which rotates the link member around the predetermined rotation axis, wherein by rotating the link member in a first direction by the actuator, the position of the second connection point changes, thereby increasing the negative camber of the wheel and the position of the third connection point changes, thereby increasing the vehicle height; and by rotating the link member in a second direction opposite to the first direction by the actuator, the position of the second connection point changes, thereby decreasing the negative camber of the wheel and the position of the third connection point changes, thereby decreasing the vehicle height.

[0011] As described above, according to the present disclosure, the camber angle of the wheels can be appropriately set in accordance with changes in vehicle height.

[0012] FIG. 1 is a schematic diagram showing an example configuration of a suspension device according to a first embodiment of the present disclosure. FIG. 2 is an explanatory diagram showing displacement of a first connection point, a second connection point, and a third connection point accompanying rotation of a link member of the suspension device according to the embodiment. FIG. 3 is an explanatory diagram showing displacement of the first connection point, the second connection point, and the third connection point accompanying rotation of the link member of the suspension device according to the embodiment. FIG. 4 is an explanatory diagram showing a state in which the link member of the suspension device according to the embodiment has been rotated in a first direction. FIG. 5 is an explanatory diagram showing an example of a suspension device according to the embodiment, where the axial direction of the rotation shaft of the link member is aligned with the fore-and-aft direction (X direction) of the vehicle. FIG. 6 is an explanatory diagram showing an example of a suspension device according to the embodiment, where the axial direction of the rotation shaft of the link member is inclined rearward with respect to the fore-and-aft direction (X direction) of the vehicle. FIG. 7 is a schematic diagram showing an example configuration of a suspension device according to a second embodiment of the present disclosure. FIG. 8 is an explanatory diagram showing a state in which the link member of the suspension device according to the embodiment has been rotated in a first direction.

[0013] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0014] First Embodiment Configuration of Suspension Device First, an example of the configuration of a suspension device according to a first embodiment of the present disclosure will be described.

[0015] Fig. 1 is a schematic diagram showing an example of the configuration of a suspension device 10 according to a first embodiment. The suspension device 10 shown in Fig. 1 is a suspension device that suspends the front wheels of a four-wheeled vehicle. The suspension device 10 is provided for each of the left and right front wheels.

[0016] The illustrated suspension device 10 is a double-wishbone type suspension device and includes a housing 15, an upper arm 17, a lower arm 19, a damper (shock absorber) 23, a link member 25, and an actuator 27.

[0017] The housing 15 accommodates a hub bearing (not shown) that rotatably supports the wheel 11. The upper arm 17 and the lower arm 19 are arranged above and below with a gap between them, and connect the housing 15 to the body structure 13 so that the housing 15 can move up and down. The upper arm 17 and the lower arm 19 each constitute a suspension arm. The damper 23 is a buffer device that includes a coil spring 21 and absorbs impacts transmitted to the wheel 11, and has a lower end connected to the housing 15. The link member 25 and the actuator 27 are interposed between the upper arm 17 and the body structure 13.

[0018] The link member 25 is a member having a predetermined rigidity, and is axially rotatably supported on a predetermined rotation shaft 31 provided on the body structure 13. For example, the link member 25 is made of a steel part. The illustrated link member 25 has a triangular prism shape, but the three-dimensional shape of the link member 25 is not particularly limited. The illustrated rotation shaft 31 is provided such that its axial direction is aligned with the fore-and-aft direction (X direction) of the vehicle when viewed in the vehicle height direction (Z direction). When viewed in the vehicle width direction (Y direction), the rotation shaft 31 may be parallel to the fore-and-aft direction of the vehicle, or may be inclined by a predetermined amount.

[0019] The link member 25 has a first connection point 33, a second connection point 35, and a third connection point 37. The first connection point 33 is connected to the vehicle body structure 13 via the actuator 27. The second connection point 35 is connected to the upper arm 17. The third connection point 37 is connected to an upper part of the damper 23. The first connection point 33, the second connection point 35, and the third connection point 37 are connected to their respective connected objects by joint structures that are rotatable around rotation axes that are parallel to the axial direction of the rotation shaft 31.

[0020] The actuator 27 is connected to the link member 25, and rotates the link member 25 around a predetermined rotation axis 31 as the actuator 27 moves forward and backward. The actuator 27 is driven by a control device (not shown) and moves forward and backward in the vehicle width direction relative to the body structure 13. For example, the actuator 27 may be an electric or hydraulic actuator including a cylinder and a piston that moves forward and backward within the cylinder. Among these, the actuator 27 is preferably an air actuator (air spring) that can control the stroke amount of the piston by controlling the supply and discharge of compressed air. By using the actuator 27 as an air actuator, a damping function can be imparted to the connection portion between the link member 25 and the body structure 13, and this can work in cooperation with the damper 23 to reduce vibrations that the wheels 11 receive from the road surface.

[0021] The second connection point 35 is located below the height position of the rotation shaft 31, and the third connection point 37 is located laterally outward of the rotation shaft 31. Therefore, when the second connection point 35 is displaced inward in the vehicle width direction as the link member 25 rotates, the third connection point 37 is displaced downward. Conversely, when the second connection point 35 is displaced outward in the vehicle width direction as the link member 25 rotates, the third connection point 37 is displaced upward.

[0022] 2 and 3 are explanatory diagrams showing displacements of the first connection point 33, the second connection point 35, and the third connection point 37 accompanying rotation of the link member 25. In the example of the suspension device 10 according to this embodiment, the first connection point 33 is located above the height position of the rotation shaft 31 and further inward in the vehicle width direction than the third connection point 37. As shown in FIG. 2 , when the piston of the actuator 27 is advanced, the link member 25 rotates in a first direction D1 in which the first connection point 33 is displaced outward in the vehicle width direction, the second connection point 35 is displaced inward in the vehicle width direction, and the third connection point 37 is displaced downward. As a result, the negative camber of the wheel 11 increases, and the height of the wheel 11 relative to the body structure 13 decreases, increasing the vehicle height.

[0023] 4 shows a state in which the link member 25 is rotated in the first direction D1 from the state shown in FIG. 1. As the link member 25 rotates, the second connecting point 35 is displaced inward in the vehicle width direction, and the third connecting point 37 is displaced downward. As a result, the upper part of the wheel 11 is pulled toward the body structure 13, increasing the negative camber. Furthermore, the wheel 11 is displaced downward relative to the body structure 13, increasing the vehicle height relative to the road surface.

[0024] 3, when the piston of the actuator 27 is retracted, the link member 25 rotates in a second direction in which the first connecting point 33 is displaced inward in the vehicle width direction, the second connecting point 35 is displaced outward in the vehicle width direction, and the third connecting point 37 is displaced upward. As a result, the vehicle changes from the state shown in Fig. 4 to the state shown in Fig. 1, the negative camber of the wheel 11 decreases, and the height of the wheel 11 relative to the body structure 13 increases, thereby decreasing the vehicle height.

[0025] The positional relationship between the rotation axis 31, the first connection point 33, the second connection point 35 and the third connection point 37 is not particularly limited as long as the relationship is satisfied in which rotating the link member 25 in a predetermined first direction increases the negative camber of the wheel 11 and increases the vehicle height, and rotating the link member 25 in a second direction opposite to the first direction decreases the negative camber of the wheel 11 and decreases the vehicle height.

[0026] However, in the suspension device 10 shown in FIG. 1 , when viewing the link member 25 along the axial direction of the rotating shaft 31, the distance L1 between the rotating shaft 31 and the first connecting point 33 is longer than the distance L2 between the rotating shaft 31 and the third connecting point 37 (L1 > L2: see FIG. 2 ). This reduces the thrust of the actuator 27, contributing to a lighter actuator 27 and ultimately a lighter vehicle. Furthermore, because the distance L1 is greater than the distance L2, the force that the actuator 27 receives in response to the input from the damper 23 is smaller than when the distance L2 is greater than or equal to the distance L1, thereby improving the rigidity of the mounting point of the damper 23. The increased rigidity of the mounting point allows the damper 23 to act as the main force, reducing unnecessary spring components and increasing the influence of the damping term in the vibration equation, thereby improving ride comfort and reducing vibration and noise.

[0027] In the suspension device 10 according to this embodiment, the camber angle is set to an appropriate angle (initial camber) based on the state in which the vehicle height is relatively low, as shown in Fig. 1. In Fig. 1, the up-down direction of the wheels 11 is perpendicular to the road surface, but the initial camber in a state in which the vehicle height is low is set to a slightly negative camber.

[0028] While the vehicle is traveling, the vehicle height can be raised by driving the actuator 27. In this case, a negative camber equal to or greater than the initial camber can be maintained without changing the camber angle in the positive direction. For example, while the vehicle is turning with a low vehicle height, the actuator 27 of the outer wheel 11 is driven to raise the vehicle height on the outer wheel side, thereby generating anti-roll. At this time, the camber angle of the outer wheel 11 changes in the negative direction, allowing the camber angle with respect to the road surface to be set appropriately.

[0029] Furthermore, in the suspension device 10 according to this embodiment, when the wheel 11 rides over a bump while the vehicle is traveling, the third connection point 37 to which the damper 23 is connected moves upward while tracing an arc. In other words, the third connection point 37 moves upward while approaching the vehicle body structure 13. Therefore, even if the stroke amount of the damper 23 is relatively short, it is possible to obtain a stroke amount equivalent to that of a damper 23 with a relatively long stroke amount. Furthermore, even in this case, the camber angle of the wheel 11 can be maintained on the negative side.

[0030] On the other hand, in the suspension device 10 according to this embodiment, when the wheel 11 hits a bump while the vehicle is traveling and rebounds, the third connection point 37 to which the damper 23 is connected moves downward while tracing an arc. In other words, the third connection point 37 moves downward while moving away from the vehicle body structure 13. Therefore, even if the stroke of the damper 23 is relatively short, it is possible to achieve a stroke equivalent to that of a damper 23 with a relatively long stroke. Furthermore, even in this case, the camber angle of the wheel 11 can be maintained on the negative side.

[0031] Furthermore, the suspension device 10 according to this embodiment has a configuration in which the upper arm 17 is connected to the vehicle body structure 13 via the link member 25. Therefore, it is not necessary to change the position of the lower arm 19, and the function of the present disclosure can be installed in the vehicle while maintaining the tread width of the wheel 11.

[0032] <Tilt of Rotation Axis of Link Member> The rotation axis 31 of the link member 25 may be tilted in the front-rear direction with respect to a two-dimensional plane of the front-rear, left-right, and right-left of the vehicle body structure 13. For example, the rotation axis 31 of the link member 25 is provided such that the axial direction is along the front-rear direction (X direction) of the vehicle when viewed in the vehicle height direction (Z direction), while when viewed in the vehicle width direction (Y direction), the rotation axis 31 may be parallel to the front-rear direction (X direction) of the vehicle or may be tilted to a predetermined degree.

[0033] 5 shows an example in which the axis of the rotation shaft 31 of the link member 25 is arranged along the front-to-rear direction (X direction) of the vehicle when the suspension device 10 is viewed in the vehicle width direction (Y direction). In the example shown, the fixed end of the upper arm 17 on the housing 15 side moves on a plane whose two axes are the vehicle height direction (Z direction) and the vehicle width direction (Y direction). This allows the wheelbase of the front and rear wheels to remain unchanged, or if it does change, the change can be kept to an extremely small amount.

[0034] 6 shows an example in which, when the suspension device 10 is viewed in the vehicle width direction (Y direction), the axial direction of the rotation shaft 31 of the link member 25 is tilted rearward with respect to the vehicle's fore-and-aft direction (X direction). In the example shown, the fixed end of the upper arm 17 on the housing 15 side moves on a plane that is tilted at a predetermined angle from a plane having two axes defined by the vehicle's height direction (Z direction) and vehicle width direction (Y direction). This makes it possible to change the wheelbase of the front and rear wheels, thereby generating anti-roll in the wheels 11 and increasing the negative camber, and by shortening the wheelbase, the vehicle's cornering performance can be improved.

[0035] Second Embodiment Next, an example of the configuration of a suspension device according to a second embodiment of the present disclosure will be described.

[0036] 7 is a schematic diagram showing an example of the configuration of a suspension device 50 according to the second embodiment. The suspension device according to the second embodiment has a configuration in which a lower arm 19 is connected to a body structure 13 via a link member 55. Below, the differences from the configuration of the suspension device 10 according to the first embodiment will be mainly described.

[0037] The illustrated suspension device 50 is a double wishbone type suspension device and includes a housing 15, an upper arm 17, a lower arm 19, a damper (shock absorber) 23, a link member 55, and an actuator 27. In this embodiment, the link member 55 and the actuator 27 are interposed between the lower arm 19 and the body structure 13.

[0038] The link member 55 has a first connection point 33, a second connection point 35, and a third connection point 37. The first connection point 33 is connected to the vehicle body structure 13 via the actuator 27. The second connection point 35 is connected to the lower arm 19. The third connection point 37 is connected to an upper part of the damper 23. The first connection point 33, the second connection point 35, and the third connection point 37 are each connected to their respective counterparts by a joint structure that is rotatable around a rotation axis that is parallel to the axial direction of the rotation shaft 31.

[0039] The second connection point 35 is located below the height position of the rotation shaft 31, and the third connection point 37 is located laterally inward of the rotation shaft 31. Therefore, when the second connection point 35 is displaced outward in the vehicle width direction as the link member 55 rotates, the third connection point 37 is displaced downward. Conversely, when the second connection point 35 is displaced inward in the vehicle width direction as the link member 55 rotates, the third connection point 37 is displaced upward.

[0040] Figure 8 shows a state in which the link member 55 has been rotated in the first direction D1 from the state shown in Figure 7. As the link member 55 rotates, the second connecting point 35 is displaced outward in the vehicle width direction, and the third connecting point 37 is displaced downward. This causes the lower part of the wheel 11 to be pushed away from the body structure 13, increasing the negative camber. Furthermore, the wheel 11 is displaced downward relative to the body structure 13, increasing the vehicle height relative to the road surface.

[0041] 8 in a second direction opposite to the first direction D1, the second connecting point 35 is displaced inward in the vehicle width direction, and the third connecting point 37 is displaced upward. As a result, the negative camber of the wheel 11 is reduced, and the height of the wheel 11 relative to the body structure 13 is increased, thereby reducing the vehicle height.

[0042] The positional relationship between the rotation axis 31, the first connection point 33, the second connection point 35 and the third connection point 37 is not particularly limited as long as the relationship is satisfied in which, by rotating the link member 55 in a predetermined first direction, the negative camber of the wheel 11 increases and the vehicle height increases, and, by rotating the link member 55 in a second direction opposite to the first direction, the negative camber of the wheel 11 decreases and the vehicle height decreases.

[0043] Like the suspension system 10 according to the first embodiment, the suspension system 50 according to this embodiment also makes it possible to appropriately set the camber angle with respect to the road surface depending on the vehicle's running state. Furthermore, the suspension system 50 according to this embodiment has a configuration in which the lower arm 19 is connected to the vehicle body structure 13 via a link member 55. This allows the actuator 27 to be installed lower than in the suspension system 10 according to the first embodiment, lowering the center of gravity and improving vehicle stability. Furthermore, by pushing the lower portion of the wheel 11 outward in the vehicle width direction, the negative camber is increased, thereby increasing the tread width of the wheel 11 and improving vehicle stability during cornering.

[0044] In the suspension unit 50 according to the second embodiment, the subframe, which is a vehicle body framework member that supports the lower arm in a conventional vehicle body structure, may also serve as the link member 55. In this case, the function of supporting drive train units such as a drive motor is transferred from the subframe to the front side frame, thereby enabling the subframe to rotate about its axis.

[0045] <<Third Embodiment>> Next, an example of a control method for the suspension device according to the first or second embodiment will be described. An example of a vehicle equipped with the suspension device 10 according to the first embodiment will be described below.

[0046] 9 shows an example of the configuration of a vehicle 60 equipped with the suspension device 10. The vehicle 60 is configured as a four-wheeled automobile equipped with a left front wheel 11LF, a right front wheel 11RF, a left rear wheel 11LR, and a right rear wheel 11RR (hereinafter, collectively referred to as "wheels 11" unless a distinction is required. Furthermore, the left front wheel 11LF and the right front wheel 11RF may be referred to as "front wheels 11F," and the left rear wheel 11LR and the right rear wheel 11RR may be referred to as "rear wheels 11R"). The vehicle 60 may be a four-wheel drive vehicle in which drive torque output from a drive power source (not shown) is transmitted to all of the wheels 11, or may be a front-wheel drive or rear-wheel drive vehicle in which drive torque is transmitted to either the front wheels 11F or the rear wheels 11R.

[0047] In the illustrated example of vehicle 60, suspension devices 10L, 10R of the present disclosure are provided on left and right front wheels 11F. Note that Fig. 9 shows only housings 15LF, 15RF and actuators 27L, 27R of suspension devices 10L, 10R.

[0048] Tire force sensors 61LF, 61RF, 61LR, and 61RR (hereinafter collectively referred to as "tire force sensors 61" unless a distinction is particularly required) are provided on each wheel 11. The tire force sensors 61 are provided, for example, on housings 15LF, 15RF, 15LR, and 15RR (hereinafter collectively referred to as "housings 15" unless a distinction is particularly required) of the respective wheels 11. The tire force sensors 61 are load sensors that detect the load applied to each wheel 11.

[0049] For example, the tire force sensor 61 may be a six-component force detector that detects loads (Fx, Fy, Fz) generated in each of the three axial directions of the wheel 11, i.e., the fore-and-aft direction (x-axis), the width direction (y-axis), and the height direction (z-axis), as well as moments (Mx, My, Mz) generated around each of the three axes. The load generated in the fore-and-aft direction (x-axis direction) of the contact surface of the wheel 11 corresponds to the fore-and-aft force Fx, the load generated in the width direction (y-axis direction) corresponds to the lateral force Fy, and the load generated in the height direction (z-axis direction) corresponds to the ground reaction force Fz.

[0050] The left and right front wheels 11F are provided with stroke sensors 63L, 63R (hereinafter collectively referred to as "stroke sensors 63" unless a distinction is required). The stroke sensors 63 detect the stroke amounts of the dampers 23 of the suspension units 10L, 10R (hereinafter also referred to as "suspension strokes").

[0051] The vehicle 60 also includes a steering angle sensor 65 and an inertial measurement unit 67. The steering angle sensor 65 is provided, for example, on a steering column and detects the rotation angle of the steering wheel. The inertial measurement unit 67 includes one or more acceleration sensors and angular velocity sensors. For example, the acceleration sensor detects the longitudinal acceleration, lateral acceleration, and vertical acceleration of the vehicle 60. The angular velocity sensor detects the angular velocity and angular acceleration of rotations (yaw, roll, and pitch) around axes in the longitudinal, transverse, and vertical directions of the vehicle 60.

[0052] The vehicle 60 is equipped with a control device 70 that controls the drive of the suspension devices 10L, 10R. The control device 70 functions as a device that controls the drive of the suspension device 10 by having one or more processors, such as CPUs, execute a computer program. The computer program is a computer program that causes the processor to execute the operations, described below, that should be performed by the control device 70. The computer program executed by the processor may be recorded on a recording medium that functions as a memory provided in the control device 70, or may be recorded on a recording medium built into the control device 70 or any recording medium that can be externally attached to the control device 70.

[0053] Examples of recording media for recording computer programs include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs (Compact Disc Read Only Memory), DVDs (Digital Versatile Discs), and Blu-ray (registered trademark); magneto-optical media such as floptical disks; memory elements such as RAMs (Random Access Memory) and ROMs (Read Only Memory); and flash memories such as USB (Universal Serial Bus) memories and SSDs (Solid State Drives), as well as other media capable of storing programs.

[0054] The control device 70 is connected to the tire force sensor 61, stroke sensor 63, steering angle sensor 65, and inertial measurement unit 67 via a dedicated line or communication means such as a controller area network (CAN) or local internet (LIN). The control device 70 is also connected to the actuators 27L, 27R of the suspension units 10L, 10R so as to be able to communicate with each other.

[0055] The control device 70 includes a processing unit 71 and a storage unit 73. The processing unit 71 includes one or more processors such as CPUs and various peripheral components. Part or all of the processing unit 71 may be configured with updatable firmware or the like, or may be a program module or the like that is executed by commands from the CPU or the like.

[0056] The storage unit 73 is composed of one or more storage elements such as RAM or ROM connected to the processing unit 71 so as to be able to communicate with it. However, the type and number of storage units 73 are not particularly limited. The storage unit 73 stores information such as computer programs executed by the processing unit 71, various parameters used in arithmetic processing, detection data, and arithmetic results. A part of the storage unit 73 is used as a work area for the processing unit 71.

[0057] 10 is a flowchart showing an example of drive control of suspension units 10L, 10R by processing unit 71. After detecting the start of driving of vehicle 60 (step S11), processing unit 71 detects the suspension strokes of suspension units 10L, 10R of left and right front wheels 11F based on the sensor signal of stroke sensor 63 (step S13).

[0058] Next, the processing unit 71 detects the running state of the vehicle 60 (step S15). For example, the processing unit 71 detects, as information about the running state of the vehicle 60, tire force information detected based on the sensor signal of the tire force sensor 61, steering angle information detected based on the sensor signal of the steering angle sensor 65, and information about the longitudinal acceleration, lateral acceleration, vertical acceleration, yaw angle, yaw rate, roll angle, roll rate, pitch angle, pitch rate, and vehicle speed of the vehicle body measured by the inertial measurement unit 67.

[0059] Next, the processing unit 71 calculates the target stroke amount (target drive amount) of the actuators 27L, 27R of the suspension units 10L, 10R based on the detected information on the running state of the vehicle 60 (step S17). For example, the processing unit 71 determines whether the suspension stroke of the left and right front wheels 11LF, 11RF is caused by bouncing or by rolling behavior based on information on the steering angle, tire force, and vertical acceleration.

[0060] When the vehicle 60 is turning, a tire force is generated on the front wheel 11F, and as the yaw rate of the vehicle 60 increases, a tire force is generated on the rear wheel 11R, which generates lateral acceleration and causes the vehicle body to roll. Therefore, if the suspension stroke of the left and right front wheels 11LF, 11RF is caused by a rolling behavior, the processing unit 71 calculates an estimated amount of rolling based on the tire force and calculates target stroke amounts for the actuators 27L, 27R. Alternatively, the processing unit 71 calculates an estimated amount of rolling based on the yaw rate and the lateral force of the wheels 11, and calculates target stroke amounts for the actuators 27L, 27R.

[0061] Furthermore, while the vehicle 60 is turning, the processing unit 71 detects the actual roll angle of the vehicle 60 based on the measurement values ​​of the inertial measurement unit 67 and the stroke sensors 63L, 63R, and sets the target stroke amounts of the actuators 27L, 27R so that the actual roll angle becomes the ideal roll angle. The target stroke amount corresponding to the estimated amount of rolling is determined in advance by simulation or the like and stored as map information or the like. Furthermore, the ideal roll angle may be determined in advance according to, for example, the vehicle speed, steering angle, and vehicle weight.

[0062] Next, the processing unit 71 drives the actuators 27L, 27R based on the calculated target stroke amounts of the actuators 27L, 27R (step S19), thereby adjusting the height and camber angle of each of the left and right front wheels 11F relative to the body structure 13 in accordance with the running state of the vehicle 60, thereby improving running stability.

[0063] Next, the processing unit 71 determines whether or not the driving of the vehicle 60 has ended (step S21). If the processing unit 71 does not determine that the driving of the vehicle 60 has ended (S21 / No), the process returns to step S13, and the processing unit 71 controls the drive of the suspension unit 10 in accordance with the running state of the vehicle 60. On the other hand, if the processing unit 71 determines that the driving of the vehicle 60 has ended (S21 / Yes), the processing unit 71 ends the process of controlling the drive of the suspension unit 10.

[0064] In the suspension system according to this embodiment, the control device 70 sets the target stroke amounts of the actuators 27L, 27R based on information about the driving state of the vehicle 60, and controls the actuators 27L, 27R. As a result, even if rolling occurs while the vehicle 60 is turning, the driving stability of the vehicle 60 can be improved by generating anti-roll in the wheels 11 and changing the camber angle in the negative direction.

[0065] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0066] For example, in each of the above embodiments, the second connection point 35 and the third connection point 37 are different connection points, but the second connection point 35 and the third connection point 37 may be shared. Even in this case, the effects of each of the above embodiments can be obtained as long as the relationship is satisfied that by rotating the link member in a predetermined first direction, the negative camber of the wheel increases and the vehicle height increases, and by rotating the link member in a second direction opposite to the first direction, the negative camber of the wheel decreases and the vehicle height decreases.

[0067] DESCRIPTION OF SYMBOLS 10, 10L, 10R: Suspension device 11: Wheel 13: Vehicle body structure 15: Housing 17: Upper arm 19: Lower arm 21: Coil spring 23: Damper 25: Link member 27: Actuator 27L, 27R: Actuator 31: Rotation shaft 33: First connection point 35: Second connection point 37: Third connection point 50: Suspension device 55: Link member 60: Vehicle 61LF, 61LR, 61RF, 61RR: Tire force sensor 63L, 63R: Stroke sensor 65: Steering angle sensor 67: Inertial measurement unit 70: Control device 71: Processing unit 73: Memory unit D1: First direction D2: Second direction

Claims

1. A suspension device comprising: a link member connected between a suspension arm that suspends a wheel and a vehicle body structure, the link member having a first connection point connected to the vehicle body structure, a second connection point connected to the suspension arm, and a third connection point connected to a damper that absorbs impacts transmitted to the wheel, the link member rotating around a predetermined rotation axis; and an actuator provided between the first connection point and the vehicle body structure, which rotates the link member around the predetermined rotation axis, wherein by rotating the link member in a first direction with the actuator, the position of the second connection point changes, increasing the negative camber of the wheel and the position of the third connection point changes, increasing the vehicle height; and by rotating the link member in a second direction opposite to the first direction with the actuator, the position of the second connection point changes, decreasing the negative camber of the wheel and the position of the third connection point changes, decreasing the vehicle height.

2. The suspension device according to claim 1, wherein the rotation axis of said link member is inclined in the front-rear direction with respect to the two-dimensional front-rear and left-right plane of said vehicle body structure.

3. The suspension device according to claim 1, wherein the distance between said predetermined rotation axis and said first connecting point is longer than the distance between said predetermined rotation axis and said third connecting point.

4. A suspension device according to claim 1, wherein when the suspension arm to which the link member is connected is a lower arm, a subframe, which is a vehicle body frame member that supports the lower arm, also serves as the link member.

5. The suspension system of claim 1, wherein said actuator is an air actuator.

6. A suspension device according to claim 1, further comprising a control device that controls the actuator, wherein the control device sets a target drive amount for the actuator based on information about the vehicle's running state, and controls the actuator.

7. A vehicle equipped with a suspension device for suspending wheels, wherein the suspension device comprises: a link member connected between a suspension arm that suspends the wheel and a vehicle body structure, the link member having a first connection point connected to the vehicle body structure, a second connection point connected to the suspension arm, and a third connection point connected to a damper that absorbs impacts transmitted to the wheel, the link member rotating around a predetermined rotation axis; and an actuator provided between the first connection point and the vehicle body structure, which rotates the link member around the predetermined rotation axis, wherein by rotating the link member in a first direction with the actuator, the position of the second connection point changes, increasing the negative camber of the wheel and changing the position of the third connection point, thereby increasing the vehicle height; and by rotating the link member in a second direction opposite to the first direction with the actuator, the position of the second connection point changes, decreasing the negative camber of the wheel and changing the position of the third connection point, thereby decreasing the vehicle height.

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