JP5652341B2 - Vehicle suspension system - Google Patents

Description

  The present invention relates to a vehicle suspension apparatus.

  Conventionally, techniques for controlling the attitude of a vehicle have been proposed. For example, Patent Document 1 discloses a tilt control that reversely expands and contracts the left and right vehicle height adjustment cylinders to maintain the traveling vehicle body in a set posture based on a detection result by an inclination detection unit that detects a right and left inclination angle of the traveling vehicle body. A technique of a tilt control device in a traveling vehicle provided with means is disclosed.

JP 09-142345 A

  There is still room for improvement in suppressing vehicle tilt. For example, when an attempt is made to control the attitude of a vehicle with an air spring, it takes time to realize the desired attitude. It is desired that the inclination of the vehicle can be appropriately suppressed, for example, the inclination of the vehicle can be suppressed with good response according to changes in the road surface and the like.

  The objective of this invention is providing the suspension apparatus for vehicles which can suppress the inclination of a vehicle appropriately.

The suspension device for a vehicle according to the present invention includes an air spring provided on each of the left wheel and the right wheel, an active stabilizer that connects the left wheel and the right wheel, and generates a force in a roll direction with respect to the vehicle, When the difference between the left and right vehicle heights changed by the air spring according to the road surface condition at the time of stop is greater than or equal to a predetermined threshold value, the vehicle height difference is corrected and the vehicle height difference is When the vehicle height is changed according to the traveling road surface state of the vehicle, the vehicle height is adjusted by the air spring and until the vehicle height adjustment by the air spring is completed , the force in the roll direction generated by the active stabilizer is used. The vehicle is characterized by suppressing left and right inclination of the vehicle.

  In the above vehicle suspension device, it is preferable to supply and exhaust air to each of the left wheel air spring and the right wheel air spring as vehicle height adjustment by the air spring.

  In the above vehicle suspension device, it is preferable that the force in the roll direction generated by the active stabilizer is reduced in accordance with the progress of vehicle height adjustment by the air spring.

  In the vehicle suspension device, it is preferable that the air chamber of the left wheel air spring and the air chamber of the right wheel air spring communicate with each other as vehicle height adjustment by the air spring.

  In the vehicle suspension apparatus, it is preferable that the active stabilizer compensates for a decrease in roll rigidity caused by the communication between the air chambers.

  A vehicle suspension apparatus according to the present invention includes an air spring provided on each of a left wheel and a right wheel, an active stabilizer that connects the left wheel and the right wheel, and generates a force in a roll direction with respect to the vehicle. When the difference between the left and right vehicle heights changed by the air spring according to the road surface condition at the time of stopping is changed according to the running road surface state after starting, the vehicle height adjustment by the air spring and the active stabilizer are generated. The left / right inclination of the vehicle is suppressed by the force in the roll direction. According to the vehicle suspension device of the present invention, there is an effect that the inclination of the vehicle can be appropriately suppressed.

FIG. 1 is a flowchart of control according to the embodiment. FIG. 2 is a flowchart of first vehicle height control according to the embodiment. FIG. 3 is a flowchart of second vehicle height control according to the embodiment. FIG. 4 is a diagram illustrating a schematic configuration of the vehicle according to the embodiment.

  Hereinafter, a vehicle suspension apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]
The embodiment will be described with reference to FIGS. 1 to 4. The present embodiment relates to a vehicle suspension apparatus. FIG. 1 is a flowchart of control according to the embodiment, FIG. 2 is a flowchart of first vehicle height control according to the embodiment, FIG. 3 is a flowchart of second vehicle height control according to the embodiment, and FIG. It is a figure showing a schematic structure of vehicles concerning.

  Some air suspension systems can adjust the vehicle height even when stopping on some rough terrain. For example, when the two left wheels are on the curb, the load moves to the right and the vehicle body falls to the right, but the air suspension system adjusts the left and right vehicle heights so as to make the vehicle height parallel to the road surface. When the vehicle begins to travel on a flat road with the vehicle height adjusted to the curb, the air suspension system adjusts the vehicle height again so that the vehicle body is level, but until the vehicle height adjustment is completed. Will end up in a right-up position.

  The vehicle suspension device 1-1 of the present embodiment corrects the posture of the vehicle by the active stabilizer until the target posture is realized by adjusting the vehicle height by the air suspension system. This makes it possible to maintain an appropriate vehicle height and vehicle posture even during vehicle height adjustment by the air suspension system. Therefore, according to the vehicle suspension apparatus 1-1 of the present embodiment, it is possible to suppress the inclination of the vehicle in the left-right direction during the adjustment of the vehicle posture by the air suspension system.

  A vehicle suspension apparatus 1-1 shown in FIG. 4 includes a front wheel active stabilizer 10, a rear wheel active stabilizer 20, an ECU 30, and an air suspension system 40. Each of the active stabilizers 10 and 20 is a stabilizer device having variable roll rigidity, and can generate a force in the roll direction with respect to the vehicle 100. The roll direction is a direction around the front-rear axis that is an axis along the front-rear direction of the vehicle 100. For example, the active stabilizers 10 and 20 have a function as a roll suppressing device that generates an anti-roll moment that suppresses the roll of the vehicle 100. The active stabilizers 10 and 20 suppress the roll of the vehicle 100 by generating an anti-roll moment with respect to the roll of the vehicle 100. The target value of the anti-roll moment is calculated based on, for example, the lateral G, the yaw rate, the vehicle speed, the steering angle, and the like.

  The front wheel active stabilizer 10 connects the left front wheel and the right front wheel of the vehicle 100, and can generate a force in the roll direction on at least the front portion of the vehicle 100. The front wheel active stabilizer 10 includes stabilizer bar members 11 and 12 and an actuator 13. The stabilizer bar members 11 and 12 are supported by the vehicle body. The stabilizer bar member 11 connects the actuator 13 and the holding member 80FR that holds the right front wheel. The stabilizer bar member 12 connects the actuator 13 and the holding member 80FL that holds the left front wheel.

  The stabilizer bar members 11 and 12 include torsion bar portions 11a and 12a extending in the vehicle width direction and arm portions 11b and 12b formed integrally with the torsion bar portions 11a and 12a and extending in the vehicle front-rear direction, respectively. Have. An end portion of the arm portion 11b opposite to the torsion bar portion 11a side is connected to a holding member 80FR that holds the right front wheel, for example, a lower arm. Further, the end portion of the arm portion 12b opposite to the torsion bar portion 12a side is connected to a holding member 80FL that holds the left front wheel, for example, a lower arm.

  The actuator 13 controls the relative amount of twist between the stabilizer bar member 11 on the right front wheel side and the stabilizer bar member 12 on the left front wheel side. The actuator 13 includes an electric motor having a stator and a rotor. One of the stabilizer bar members 11 and 12 is connected to the stator side of the motor, and the other is connected to the rotor side of the motor. Therefore, the relative rotation amount of the stabilizer bar member 11 and the stabilizer bar member 12 can be controlled by controlling the rotation amount of the motor.

  When a twisting force is applied to the stabilizer bar members 11 and 12 by the roll of the vehicle 100, the stabilizer bar members 11 and 12 are relatively rotated in the direction opposite to the twisting direction by the torsional force by the actuator 13. A force in the roll direction can be generated on the part, and an anti-roll moment that opposes the roll moment can be generated. If the relative rotation amount of the left and right stabilizer bar members 11 and 12 is changed by changing the rotation amount of the actuator 13 by the motor force, the anti-roll moment as the roll restraining force changes, and the roll of the vehicle body is changed. It can be actively suppressed.

  Note that the amount of rotation of the actuator 13 here means that when the vehicle 100 is stationary in a horizontal posture on a flat road as a reference state, and the rotation position of the actuator 13 in the reference state is a neutral position, This means the amount of rotation from the neutral position, that is, the amount of movement. Therefore, as the amount of rotation of the actuator 13 increases, the rotational position of the actuator 13 moves away from the neutral position, and the torsional reaction force of the stabilizer bar members 11, 12, that is, the roll suppression force increases.

  The rear wheel active stabilizer 20 connects the left rear wheel and the right rear wheel of the vehicle 100, and can generate a force in the roll direction on at least the rear portion of the vehicle 100. The rear wheel active stabilizer 20 includes the same components as the front wheel active stabilizer 10, and includes stabilizer bar members 21 and 22 and an actuator 23. The stabilizer bar members 21 and 22 have torsion bar members 21a and 22a and arm portions 21b and 22b, respectively, and are supported by the vehicle body. The stabilizer bar member 21 connects the actuator 23 and the holding member 80RR that holds the right rear wheel. The stabilizer bar member 22 connects the actuator 23 and the holding member 80RL that holds the left rear wheel. The actuator 23 generates a force in the roll direction with respect to the rear portion of the vehicle 100 by changing the relative rotation amount of the left and right stabilizer bar members 21 and 22 by the motor force, and changes the roll restraining force on the rear wheel side. . Thus, the active stabilizers 10 and 20 are variable twist angle stabilizers that can variably control the twist angle between the left and right stabilizer bar members.

  The air suspension system 40 includes an air spring 41 (41FR, 41FL, 41RR, 41RL), a filter 42, a compressor 43, a motor 44, check valves 45 and 46, an orifice 47, a dryer 48, a high pressure tank 49, an exhaust valve 50, and a low pressure tank. 51, a height control valve 52 (52FR, 52FL, 52RR, 52RL), an air pipe 53 and a discharge pipe 54 are provided. In the air spring 41 and the height control valve 52, the subscript FR indicates the right front wheel, FL indicates the left front wheel, RR indicates the right rear wheel, and RL indicates the components related to the left rear wheel.

  The air spring 41 is an air suspension that supports the vehicle 100, and has a vehicle height adjustment function that adjusts the vehicle height of the vehicle 100.

  The air spring 41 is provided together with the shock absorber 60. The shock absorber 60 has an outer cylinder 61 and a piston rod 62. The outer cylinder 61 has a hollow cylindrical shape, and a working fluid, for example, oil is enclosed therein. The piston rod 62 has a piston portion that is disposed inside the outer cylinder 61 and slides along the inner wall surface of the outer cylinder 61. The inside of the outer cylinder 61 is partitioned into a piston upper chamber and a piston lower chamber by a piston portion. The piston portion is formed with a communication path that connects the piston upper chamber and the piston lower chamber. The lower end of the outer cylinder 61 is supported via a bushing 63 by a holding member 80 (80FR, 80FL, 80RR, 80RL) that holds a wheel.

  The air spring 41 includes a vehicle body side outer shell member 41a, a wheel side outer shell member 41b, and a rolling diaphragm 41c. The vehicle body side outer shell member 41 a is coupled to the piston rod 62 and can move in the axial direction of the shock absorber 60 together with the piston rod 62. Further, the vehicle body side outer shell member 41a supports the vehicle body 90 (90FR, 90FL, 90RR, 90RL). The vehicle body side outer shell member 41a of the air spring 41FR disposed on the right front wheel supports the right front wheel side 90FR of the vehicle body 90. Similarly, the air springs 41FL, 41RR, 41RL support the left front wheel side 90FL, the right rear wheel side 90RR, and the left rear wheel side 90RL of the vehicle body 90, respectively.

  The wheel side outer shell member 41 b is connected to the outer cylinder 61 of the shock absorber 60. That is, the wheel-side outer shell member 41 b is supported by the holding member 80 that holds the wheel via the outer cylinder 61. The wheel-side outer shell member 41b of the right front wheel air spring 41FR is supported by a holding member 80FR that holds the right front wheel. Similarly, the wheel side outer shell member 41b of the air springs 41FL, 41RR, 41RL is supported by a holding member 80FL that holds the left front wheel, a holding member 80RR that holds the right rear wheel, and a holding member 80RL that holds the left rear wheel, respectively. Has been.

  The rolling diaphragm 41c connects the vehicle body side outer shell member 41a and the wheel side outer shell member 41b. An air chamber 41d is formed by the vehicle body side outer shell member 41a, the rolling diaphragm 41c, and the wheel side outer shell member 41b. An air pipe 53 is connected to the air chamber 41d of each air spring 41FR, 41FL, 41RR, 41RL.

  The air pipe 53 is provided with a compressor 43. The compressor 43 is driven by the power of the motor 44 and compresses air as a working gas. The compressor 43 compresses the air sucked through the filter 42 and discharges the compressed air toward the air springs 41. A check valve 45, a check valve 46, an orifice 47, and a dryer 48 are provided between each air spring 41 and the compressor 43 in the air pipe 53 in order from the side close to the compressor 43. The check valve 45 is a check valve that allows air flow from the compressor 43 toward each air spring 41 and restricts air flow from each air spring 41 toward the compressor 43. The check valve 46 and the orifice 47 are provided in parallel. As with the check valve 45, the check valve 46 allows the air flow from the compressor 43 toward each air spring 41 and restricts the air flow in the opposite direction. The dryer 48 removes moisture contained in the air discharged from the compressor 43.

  Each air spring 41 is provided with a height control valve 52. The height control valve 52 opens and closes the air flow path between the compressor 43 and each air spring 41 in the air pipe 53. For example, the height control valve 52FR for the right front wheel opens and closes the air flow path between the air chamber 41d of the air spring 41FR and the compressor 43. When the height control valve 52FR for the right front wheel opens the flow path during the operation of the compressor 43, the air discharged from the compressor 43 flows into the air chamber 41d of the air spring 41FR for the right front wheel. Thereby, the vehicle body side outer shell member 41a of the right front wheel moves relative to the wheel side outer shell member 41b toward the upper side. That is, the vehicle body side outer shell member 41 a and the wheel side outer shell member 41 b relatively move in a direction away from each other in the axial direction of the shock absorber 60. As a result, the right front wheel side 90FR of the vehicle body 90 is separated from the ground contact surface of the right front wheel. That is, the vehicle height at the right front portion of the vehicle body 90 increases.

  The same applies to the other air springs 41. When the height control valves 52FL, 52RR, 52RL of the air springs 41FL, 41RR, 41RL are opened in a state where compressed air is supplied to the air pipe 53, the left front portion of the vehicle body 90 The vehicle heights of 90FL, right rear portion 90RR, and left rear portion 90RL are increased.

  A high pressure tank 49 is connected to the air spring 41 side of the air pipe 53 from the dryer 48. The high-pressure tank 49 has a function as an accumulator that stores the compressed air discharged from the compressor 43. The high-pressure tank 49 is provided with an open / close valve (not shown) that opens and closes an air flow path between the high-pressure tank 49 and the air pipe 53. By opening the on-off valve, the compressed air in the air pipe 53 can be received in the high-pressure tank 49, or the compressed air stored in the high-pressure tank 49 can flow out to the air pipe 53.

  The on-off valve of the high-pressure tank 49 is opened when air is supplied to the air chamber 41d of the air spring 41, for example. By letting the compressed air previously stored in the high-pressure tank 49 flow out to the air pipe 53, the compressor 43 can be assisted to quickly supply the compressed air to the air chamber 41d. Further, the compressed air can be stored in the high-pressure tank 49 by operating the compressor 43 with each height control valve 52 closed after the vehicle height adjustment is completed.

  A discharge pipe 54 is connected to the air pipe 53. The discharge pipe 54 is connected between the check valve 45 and the check valve 46 in the air pipe 53. The discharge pipe 54 connects the air pipe 53 and the low-pressure tank 51. The low pressure tank 51 is maintained at a pressure lower than the atmospheric pressure, for example. The air in the low-pressure tank 51 may be sucked by the compressor 43, for example. Alternatively, a pump or the like that sucks air in the low-pressure tank 51 may be provided.

  The exhaust pipe 54 is provided with an exhaust valve 50 that opens and closes the air flow path of the exhaust pipe 54. When the exhaust valve 50 is opened, the air in the air pipe 53 flows out to the low pressure tank 51 through the discharge pipe 54. Since the inside of the low-pressure tank 51 is at a pressure lower than the atmospheric pressure, it is possible to positively exhaust the air in the air pipe 53 more quickly than when the air in the air pipe 53 is released to the atmosphere. The exhaust valve 50 blocks the discharge pipe 54 when air is supplied to the air chamber 41d. The discharge pipe 54 may be open to the atmosphere instead of being connected to the low pressure tank 51.

  When the air in the air chamber 41d is discharged to lower the vehicle height, the compressor 43 is stopped and the exhaust valve 50 and the height control valve 52 are opened. At this time, the on-off valve of the high-pressure tank 49 is closed. By opening the height control valve 52 and the exhaust valve 50, the air in each air chamber 41 d is discharged to the air pipe 53 and flows into the low-pressure tank 51 through the discharge pipe 54. As the air in the air chamber 41d is discharged, the vehicle body side outer shell member 41a moves relative to the wheel side outer shell member 41b downward. That is, the vehicle body side outer shell member 41 a and the wheel side outer shell member 41 b relatively move in a direction approaching each other in the axial direction of the shock absorber 60. Accordingly, when the compressed air is not supplied to the air pipe 53 and the height control valves 52FR, 52FL, 52RR, 52RL of the air springs 41FR, 41FL, 41RR, 41RL are opened in a state where the exhaust valve 50 is opened, The vehicle heights of the right front portion 90FR, the left front portion 90FL, the right rear portion 90RR, and the left rear portion 90RL of the vehicle body 90 are reduced.

  The front wheel active stabilizer 10, the rear wheel active stabilizer 20, and the air suspension system 40 are each controlled by the ECU 30. The ECU 30 is an electronic control unit having a computer, for example. The actuator 13 of the front wheel active stabilizer 10 and the actuator 23 of the rear wheel active stabilizer 20 are respectively connected to the ECU 30 and controlled by the ECU 30. The motor 44, the exhaust valve 50, the high-pressure tank 49, and the height control valves 52 (52FR, 52FL, 52RR, 52RL) of the air suspension system 40 are connected to the ECU 30 and controlled by the ECU 30. The ECU 30 can further control the damping force of the shock absorber 60. For example, the ECU 30 can control the damping force when the piston rod 62 moves in the axial direction by adjusting the flow passage area of the communication path in the piston portion of the piston rod 62.

  A sensor 70 that detects the traveling state of the vehicle 100 is connected to the ECU 30. In the present embodiment, a lateral G sensor 71, a yaw rate sensor 72, a vehicle speed sensor 73, a rudder angle sensor 74, and a vehicle height sensor 75 are connected to the ECU 30.

  The lateral G sensor 71 can detect lateral G, which is acceleration in the vehicle width direction (left-right direction) generated in the vehicle 100. The yaw rate sensor 72 can detect the yaw rate of the vehicle 100. The vehicle speed sensor 73 can detect the traveling speed of the vehicle 100. The steering angle sensor 74 can detect the operation amount (steering angle) of the steering wheel operated by the driver. The vehicle height sensor 75 can detect the vehicle height of the vehicle 100. The vehicle height sensor 75 is arranged corresponding to each wheel. The vehicle height sensor 75 can detect the vehicle height in the vicinity of the wheel, that is, the height position of the vehicle body 90 with respect to the road surface on which the wheel contacts the ground. For example, the vehicle height sensor 75 disposed on the left front wheel detects the height position of the left front wheel side 90FL of the vehicle body 90 with respect to the road surface on which the left front wheel contacts. Signals indicating the detection results of the sensors 71, 72, 73, 74, 75 are output to the ECU 30, respectively. The ECU 30 is operated by electric power supplied from the power supply circuit 76.

  The ECU 30 can increase or decrease the vehicle height of each wheel independently of the vehicle height of other wheels by controlling the air spring 41 of each wheel. For example, the ECU 30 changes the amount of air in the air chamber 41d of the air spring 41 of the right wheel and the amount of air in the air chamber 41d of the air spring 41 of the left wheel, so that one side of the vehicle 100 in the width direction. It is possible to adjust the vehicle height and the vehicle height on the other side to different vehicle heights. Further, the ECU 30 can execute auto leveling control that maintains a constant vehicle height regardless of the occupant and the load capacity. In the auto leveling control, for example, the air suspension system 40 is controlled based on the vehicle height of each wheel detected by each vehicle height sensor 75 so as to maintain a constant vehicle height.

  The ECU 30 can adjust the left and right vehicle heights by the air spring 41 based on the road surface condition. For example, when the road surface is inclined in the left-right direction, or when one of the left and right wheels rides on the curb, the vehicle body 90 is inclined to the left and right due to uneven load on the left and right wheels. As an example, when two wheels, the left front wheel and the left rear wheel, ride on the curb and stop, the load on the right wheel becomes larger than the load on the left wheel, and the vehicle body 90 tilts to the right. In this case, the ECU 30 lowers the vehicle height on the left side of the vehicle by the air spring 41FL for the left front wheel and the air spring 41RL for the left rear wheel, or on the right side of the vehicle by the air spring 41FR for the right front wheel and the air spring 41RR for the right rear wheel. The right and left inclination of the vehicle body 90 is suppressed by increasing the vehicle height.

  For example, the ECU 30 controls the vehicle height so that the vehicle body 90 is parallel to the road surface. Thus, ECU30 can perform vehicle height adjustment which makes the vehicle height of right and left differ by air spring 41 based on the state of a road surface. Here, the state of the road surface includes things such as structures on the road such as curbs, road surface irregularities, road surface slopes, and the like that vary the height position in the vertical direction of the ground contact surfaces of the left and right wheels.

  In this way, starting from a state where the left and right vehicle heights are varied according to the road surface condition, the vehicle starts traveling and returns to a flat road to eliminate uneven left and right loads, or to reduce uneven left and right loads. As a result, the vehicle posture may be tilted due to the difference between the left and right vehicle heights. The vehicle suspension device 1-1 changes the difference between the left and right vehicle heights changed by the air spring 41 in accordance with the road surface state at the time of stop according to the traveling road surface state after the start. For example, when the slope of the road surface changes to something different from that at the time of stopping, the vehicle height is adjusted by the air spring 41 according to the slope of the road surface after the change. At this time, even if the vehicle height is adjusted by the air spring 41 so as to adjust the vehicle posture horizontally, a certain amount of time is required to supply and exhaust the air spring 41. For this reason, until the vehicle height adjustment is completed, traveling in a state where the vehicle body 90 is inclined to the left and right is forced. If the vehicle body 90 travels with the vehicle body tilted in this way, the driver feels uncomfortable.

  The vehicle suspension apparatus 1-1 according to the present embodiment starts from a state where the left and right vehicle heights are changed by the air spring 41 according to the road surface state, or after starting, depending on the road surface state. When the difference between the left and right vehicle heights is changed, not only the vehicle height adjustment by the air spring 41 but also the right and left inclination of the vehicle 100 is suppressed by the force in the roll direction generated by the active stabilizers 10 and 20. As a result, it is possible to suppress the inclination of the traveling vehicle 100 and improve drivability.

  For example, the ECU 30 reduces the vehicle height on the side where the vehicle height is relatively higher among the left and right sides and increases the vehicle height on the side where the vehicle height is relatively low. , 20 are controlled. Thereby, the inclination of the vehicle 100 in the transient state until the target vehicle posture corresponding to the road surface state can be realized by the vehicle height adjustment by the air spring 41 can be suppressed.

  The control of this embodiment will be described with reference to FIGS. The control flow illustrated in FIG. 1 is executed, for example, while the system of the vehicle 100 is operating, and is repeatedly executed at a predetermined interval.

  First, in step S1, the ECU 30 determines whether or not the vehicle is stopped. For example, the ECU 30 performs the determination in step S1 based on the detection result of the vehicle speed sensor 73. In addition, not only when the vehicle speed is 0, it may be determined that the vehicle is stopped when the vehicle speed is equal to or lower than a predetermined vehicle speed. If it is determined that the vehicle is stopped as a result of the determination in step S1 (step S1-Y), the process proceeds to step S2, and if not (step S1-N), the process proceeds to step S5.

  In step S2, the ECU 30 determines whether or not the vehicle height difference between left and right is large. In step S2, it is determined whether or not the vehicle 100 is stopped in a state where the vehicle 100 is tilted left and right. The ECU 30 can make the determination in step S2 based on the detection result of the vehicle height sensor 75. For example, the ECU 30 makes an affirmative determination in step S <b> 2 when the vehicle height difference between the vehicle height on the left side and the vehicle height on the right side of the vehicle body 90 is equal to or greater than a predetermined threshold. Here, the difference in vehicle height between the left front wheel and the right front wheel, the difference between the left front wheel height and the right rear wheel height, the left front wheel height, etc. And the difference between the average value of the vehicle height and the average value of the vehicle heights of the right and left front wheels may be included. As an example, the ECU 30 makes an affirmative determination in step S2 when the vehicle height difference between the front wheels and the vehicle height difference between the rear wheels are equal to or greater than a threshold value.

  Note that an affirmative determination may be made in step S2 when the difference between the front-left vehicle height difference and the rear-wheel height difference is large. Alternatively, the determination in step S2 may be made based on the twist angles of the active stabilizers 10 and 20, instead of or in addition to the vehicle height difference.

  As a result of the determination in step S2, if it is determined that the vehicle height difference is large (step S2-Y), the process proceeds to step S3. If not (step S2-N), the process proceeds to step S4.

  In step S3, the vehicle height target value is corrected by the ECU 30. The vehicle height target value is a target value of the vehicle height of each wheel determined based on the target vehicle posture. The target vehicle posture in the present embodiment is to reduce the inclination of the vehicle 100 as compared with the case where the vehicle height adjustment is not performed. From the viewpoint of comfort, it may be preferable to adjust the vehicle height so that the vehicle body 90 is parallel (or horizontally) with respect to the road surface. The amount of vehicle height adjustment when traveling back to a flat road will be large.

  In the present embodiment, the target vehicle posture is determined so that both of ensuring comfort by relaxing the inclination of the vehicle body 90 and suppressing the inclination of the vehicle body 90 after the start of traveling can be achieved. The target vehicle height is determined such that, for example, the difference between the left and right vehicle heights is half the initial difference between the left and right vehicle heights, and the average of the left and right vehicle heights is the standard vehicle height. The standard vehicle height is, for example, a standard target vehicle height when the vehicle stops or runs on a flat road, and is determined in advance. By suppressing the vehicle height adjustment based on the road surface state in this way, it is possible to reduce the vehicle height readjustment allowance when returning to a flat road after the start of traveling. When the vehicle height target value is determined in step S3, the process proceeds to step S4.

  In step S4, the vehicle height control by the air spring 41 is performed by the ECU 30. When the process proceeds from step S3 to step S4, the ECU 30 controls the air spring 41 of each wheel based on the vehicle height target value determined in step S3. Thereby, the target vehicle posture based on the road surface condition is realized. When a negative determination is made in step S2 and the process proceeds to step S4, the ECU 30 performs vehicle height control using the air spring 41. In this case, the ECU 30 may adjust the vehicle height so that the vehicle body 90 is parallel (or in a horizontal posture) with respect to the road surface. It may be omitted. When step S4 is executed, the control flow ends.

  When a negative determination is made in step S1, for example, when the process proceeds to step S5, the ECU 30 determines in step S5 whether or not the vehicle height difference between left and right is large. In step S5, it is determined whether or not the vehicle is traveling with a large vehicle height difference. The difference in vehicle height after departure reflects the road surface condition. For example, the ECU 30 may perform the determination in step S5 in the same manner as in step S2.

  In step S5, the ECU 30 may determine whether or not the vehicle body 90 is tilted left and right due to excessive or insufficient vehicle height adjustment. For example, even when the vehicle height difference between left and right is large, there may be a case where the inclination of the vehicle body 90 with respect to the horizontal direction is not so large because the road surface is inclined to some extent. In such a case, a negative determination may be made in step S5. As a result of the determination in step S5, if it is determined that the vehicle height difference is large (step S5-Y), the process proceeds to step S6. If not (step S5-N), the process proceeds to step S4.

  When a negative determination is made in step S5 and the process proceeds to step S4, vehicle height control by the air spring 41 is performed by the ECU 30 in step S4. The ECU 30 may adjust the vehicle height so that the vehicle body 90 is parallel (or in a horizontal posture) with respect to the road surface. When the vehicle height difference between the vehicle heights is sufficiently small, the vehicle height adjustment based on the road surface state is omitted. It may be. When step S4 is executed, the control flow ends.

  In step S6, the predetermined vehicle height control is performed by the ECU 30. The predetermined vehicle height control is a control that suppresses the right and left inclination of the vehicle 100 by the vehicle height adjustment by the air spring 41 and the force in the roll direction generated by the active stabilizers 10 and 20. Starting from a state where the vehicle is stopped with different left and right vehicle heights, the vehicle 90 starts to run, and when the shared load of the left and right wheels becomes equal, the vehicle body 90 tilts to the left and right. With respect to the left and right inclination of the vehicle body 90, predetermined vehicle height control is performed in step S6.

  In the present embodiment, the first vehicle height control or the second vehicle height control is executed as the predetermined vehicle height control. The first vehicle height control is to reduce the difference between the left and right vehicle heights of the vehicle body 90 by communicating the left and right air springs 41. The ECU 30 eliminates the inclination of the vehicle body 90 by causing the air springs 41 to communicate with the left and right separately. However, since the roll rigidity is temporarily reduced by communicating the left and right air springs 41, the generated force of the active stabilizers 10 and 20 is increased accordingly. As a result, it is possible to eliminate the difference between the left and right of the vehicle height while maintaining the roll rigidity.

  The second vehicle height control is to reduce the difference between the left and right vehicle heights by supplying and exhausting air to the left and right air springs 41. In the second vehicle height control, unlike the first vehicle height control, the vehicle height is adjusted by supplying and discharging air for each wheel without causing the left and right air springs 41 to communicate with each other. The ECU 30 suppresses the inclination of the vehicle body 90 by generating an active force in the active stabilizers 10 and 20 until the adjustment of the vehicle height is completed after the air is supplied to and discharged from the air spring 41 of each wheel. The ECU 30 gradually reduces the generated forces of the active stabilizers 10 and 20 as the vehicle height adjustment by the air suspension system 40 progresses. When the vehicle height becomes the standard vehicle height and the difference between the left and right vehicle heights is eliminated and the generated force of the active stabilizers 10 and 20 becomes zero, the vehicle height adjustment is finished.

  First, the first vehicle height control will be described with reference to FIG. In step S11, the left and right air springs 41 are communicated by the ECU 30. The ECU 30 communicates the air chamber 41d of the air spring 41FR of the right front wheel and the air chamber 41d of the air spring 41FL of the left front wheel when eliminating the vehicle height difference between the front wheels. Specifically, the ECU 30 closes the exhaust valve 50 and opens the air flow paths to the right front wheel height control valve 52FR and the left front wheel height control valve 52FL, respectively. As a result, the air chamber 41d of the air spring 41FR for the right front wheel and the air chamber 41d of the air spring 41FL for the left front wheel communicate with each other, and the one air chamber 41d is changed to the other air chamber 41d so as to eliminate the vehicle height difference. Air moves.

  For example, if the vehicle height is adjusted so that the air spring 41FL of the left front wheel contracts until then, if the air chamber 41d of the right front wheel communicates with the air chamber 41d of the left front wheel, the air chamber 41d of the right front wheel communicates with the left front wheel. Air moves to the air chamber 41d. Further, the ECU 30 communicates the air chamber 41d of the air spring 41RR of the right rear wheel and the air chamber 41d of the air spring 41RL of the left rear wheel when canceling the difference in vehicle height between the rear wheels. When the front wheel air chamber 41d is connected to the left and right and the rear wheel air chamber 41d is connected to the left and right, the vehicle height difference is reduced and the vehicle height difference is eliminated.

  It is arbitrary whether to eliminate the difference between the left and right front wheel heights or the difference between the right and left rear wheel heights. For example, the larger vehicle height left / right difference of the front wheel left / right difference or the rear wheel height / left / right difference may be eliminated first. When step S11 is executed, the process proceeds to step S12.

  In step S12, the ECU 30 supplements the roll stiffness by the active stabilizers 10 and 20. When the left and right air chambers 41d are communicated in step S11, the roll rigidity temporarily decreases. For example, when the left and right air chambers 41d of the front wheel are communicated, the roll rigidity of the front wheel is lower during the communication than when the communication is not performed. In this case, the ECU 30 increases the generated force of the front wheel active stabilizer 10. Thereby, the decrease in roll rigidity due to the communication between the air chambers 41d of the front wheels is compensated by the front wheel active stabilizer 10. On the other hand, when communicating the left and right air chambers 41d of the rear wheel, the ECU 30 increases the generated force of the rear wheel active stabilizer 20. As a result, the reduction in roll rigidity due to the communication between the air chambers 41 d of the rear wheels is compensated by the rear wheel active stabilizer 20. When step S12 is executed, this control flow ends, and the process proceeds to step S5 in FIG.

  Next, the second vehicle height control will be described with reference to FIG. In step S21, the ECU 30 eliminates the vehicle height difference between the active stabilizers 10 and 20. For example, the ECU 30 determines the generated force of the front wheel active stabilizer 10 and the generated force of the rear wheel active stabilizer 20 so as to reduce the vehicle height left-right difference based on the vehicle height left-right difference detected as the determination target in step S5. To do.

  As an example, the ECU 30 determines the generated forces of the active stabilizers 10 and 20 so that the vehicle body 90 is in a horizontal posture. For example, the ECU 30 determines the target generated force of the front wheel active stabilizer 10 based on the difference in the vehicle height between the front wheels, and determines the target generated force of the rear wheel active stabilizer 20 based on the difference in the vehicle height between the rear wheels. The ECU 30 controls the active stabilizers 10 and 20 based on the determined target generated force. When step S21 is executed, the process proceeds to step S22.

  In step S22, the generated force of the active stabilizers 10 and 20 is gradually reduced by the ECU 30. The ECU 30 decreases the force in the roll direction generated by the active stabilizers 10 and 20 stepwise or continuously. For example, the ECU 30 may gradually decrease the generated force of the active stabilizers 10 and 20 according to the progress of the vehicle height adjustment by the air spring 41 based on the detection result of the vehicle height sensor 75. The generated force of the stabilizers 10 and 20 may be gradually reduced. When step S22 is executed, the process proceeds to step S23.

  In step S <b> 23, the ECU 30 gives priority to eliminating the left / right difference in the vehicle height control by the air suspension system 40. For example, the ECU 30 gives priority to the vehicle height control by the second vehicle height control with respect to the request by other vehicle height control. For example, in a vehicle capable of executing vehicle height control based on the vehicle speed, cancellation of the vehicle height left-right difference by the second vehicle height control is performed with priority over adjustment of the vehicle height based on the vehicle speed. When a plurality of vehicle height control requests overlap, the ECU 30 arbitrates between the vehicle height controls and gives priority to the second vehicle height control. When step S23 is executed, the process proceeds to step S24.

  In step S24, the ECU 30 determines whether or not the generated force of the active stabilizers 10 and 20 is zero. In step S24, it is determined whether the vehicle height difference between left and right has been eliminated. For example, the ECU 30 determines whether or not the generated force of the active stabilizers 10 and 20 for eliminating the vehicle height difference is zero. That is, when the generated force of the active stabilizers 10 and 20 excluding the anti-roll moment generated when the vehicle 100 is turning is zero, the ECU 30 makes an affirmative determination in step S24. As a result of the determination in step S24, when it is determined that the generated force of the active stabilizers 10 and 20 is 0 (step S24-Y), this control flow ends and the process proceeds to step S5 in FIG. In the case (step S24-N), the process proceeds to step S22.

  According to the vehicle suspension device 1-1 of the present embodiment, in the vehicle height control while stopped on a non-flat road surface, the left and right vehicle height adjustments are made within a range in which the posture of the vehicle body 90 is not corrected to the horizontal. By suppressing excessive vehicle height control on a non-flat road surface, it is possible to reduce the inclination of the vehicle body 90 when returning to a flat road and the vehicle height control amount for eliminating the inclination.

  Further, the vehicle posture during the vehicle height adjustment by the air suspension system 40 can be kept horizontal by the first vehicle height control or the second vehicle height control. Therefore, the deterioration of appearance, the riding comfort, and the steering stability due to the inclination of the vehicle body 90 are suppressed.

  Although adjustment of the vehicle height and the vehicle posture by the air suspension system 40 takes time, there is an advantage that no power is required after the adjustment is completed. On the other hand, the active stabilizers 10 and 20 can change the vehicle posture instantaneously, but require power continuously to maintain the vehicle posture. According to the present embodiment, the right and left inclination of the vehicle body 90 can be suppressed by utilizing the advantages of the air suspension system 40 and the active stabilizers 10 and 20, and the vehicle posture can be controlled appropriately.

  In the present embodiment, the communication between the air chamber 41d for the left wheel and the air chamber 41d for the right wheel in the first vehicle height control is made via the air pipe 53, but the present invention is not limited to this. For example, a communication pipe that connects the air chamber 41d of the left wheel and the air chamber 41d of the right wheel is provided independently of the air pipe 53, and an on-off valve that opens and closes the communication pipe is provided. In the high control, the left and right air chambers 41d and 41d may be communicated with each other via a communication pipe. If the communication pipe is arranged on at least one of the front wheel side and the rear wheel side, it is possible to simultaneously eliminate the difference in the vehicle height between the front wheels and the difference in the vehicle height between the rear wheels.

  In addition, the vehicle suspension device 1-1 of the present embodiment may include another known vehicle height control device instead of the air spring 41. By assisting the vehicle height control by the vehicle height control device with the active stabilizers 10 and 20, the right and left inclination of the vehicle 100 can be appropriately suppressed.

  Although the actuators 13 and 23 of the active stabilizers 10 and 20 of the present embodiment generate a force in the roll direction by an electric motor, a drive source that generates the force in the roll direction is not limited to the electric motor.

  In step S6, whether to implement the first vehicle height control or the second vehicle height control may be selected according to the condition. For example, the first vehicle height control or the second vehicle height control may be selectively performed based on the vehicle height difference, vehicle speed, steering angle, yaw rate, lateral G, and the like.

  The contents disclosed in the above embodiments can be executed in appropriate combination.

1-1 Vehicle Suspension Device 10 Front Wheel Active Stabilizer 20 Rear Wheel Active Stabilizer 30 ECU
40 Air suspension system 41 (41FR, 41FL, 41RR, 41RL) Air spring 41d Air chamber 90 (90FR, 90FL, 90RR, 90RL) Car body 100 Vehicle

Claims (5)

An air spring provided on each of the left and right wheels;
An active stabilizer that connects the left wheel and the right wheel to generate a force in a roll direction on the vehicle;
With
When the difference between the left and right vehicle heights changed by the air spring according to the road surface condition at the time of stoppage is equal to or greater than a predetermined threshold, the vehicle height difference is corrected and the vehicle height difference is corrected after the vehicle starts running. When changing according to the state, the vehicle height adjustment by the air spring is performed and the vehicle height adjustment by the air spring is completed until the vehicle height adjustment by the active stabilizer is performed. A vehicle suspension apparatus characterized by suppressing inclination of the vehicle. The vehicle suspension device according to claim 1, wherein as a vehicle height adjustment by the air spring, air supply / exhaust is performed with respect to each of the air spring of the left wheel and the air spring of the right wheel. The vehicle suspension device according to claim 1, wherein a force in a roll direction generated by the active stabilizer is reduced in accordance with progress of vehicle height adjustment by the air spring. The vehicle suspension device according to claim 1, wherein as a vehicle height adjustment by the air spring, an air chamber of the air spring of the left wheel communicates with an air chamber of the air spring of the right wheel. The vehicle suspension apparatus according to claim 4, wherein a decrease in roll rigidity caused by communicating the air chambers is compensated by the active stabilizer.

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