JPH07215035A - Suspension controller - Google Patents

Abstract

PURPOSE:To improve wheel turning performance by properly controlling a spring constant value of a suspension spring. CONSTITUTION:A suspention having a spring constance value variable suspension spring 10 is provided in each wheel. Turning state detectors 28, 30 and 32 and controller 34 for controlling the spring constance value of the suspension spring are provided. The controller sets the spring constant value of the suspension on a turning inner wheel higher than that on a turning outer wheel, thereby the expansion of the suspension on the turning inner wheel side is made smaller than the shrinking amount of the suspension on the turning outer wheel side and the centroid weight of the car body can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension of a vehicle such as an automobile, and more particularly to a suspension controller.

[0002]

2. Description of the Related Art As one of air suspension control devices provided with air springs corresponding to respective wheels, as described in, for example, Japanese Patent Laid-Open No. 62-83210, when the vehicle travels straight, the The air chambers of the air springs are connected to each other so that the air chambers of the left and right air springs are disconnected when the vehicle is turning, and compressed air is supplied to the air chambers of the air springs on the outer wheel side of the turn. 2. Description of the Related Art Suspension control devices configured to discharge compressed air from an air chamber of a spring are conventionally known.

According to such a suspension control device,
When the vehicle travels straight, the spring constant of each air spring is maintained at a low value to ensure good ride comfort of the vehicle, and when the vehicle turns, the spring constant of each air spring is switched to a high value and turns. Since the vehicle height on the outer wheel side is increased and the vehicle height on the turning inner wheel side is reduced, the roll of the vehicle body is suppressed, whereby the steering stability of the vehicle at the time of turning of the vehicle is improved.

[0004]

However, in the conventional suspension control device as described above, compared with the case where the compressed air is not supplied to or discharged from the air chambers of the air springs on the turning outer wheel side and the turning inner wheel side. Although the roll of the vehicle body can be suppressed during turning of the vehicle, the height of the center of gravity of the vehicle body during turning is controlled to be substantially constant. Therefore, in order to improve the turning performance of the vehicle, the height of the center of gravity of the vehicle body is increased. Needs to be further improved.

The present invention has been made to solve the above-mentioned problems in the conventional suspension control device. By appropriately controlling the spring constant of the suspension spring, the center of gravity of the vehicle body at the time of turning of the vehicle is controlled. It is an object of the present invention to provide an improved suspension control device capable of reducing the height and thereby improving the turning performance of a vehicle.

[0006]

According to the present invention, the above object is to provide a vehicle suspension control device in which a suspension having a suspension spring with a variable spring constant is provided for each wheel, and the vehicle is in a turning state. And a spring constant control means for controlling a spring constant of the suspension spring, wherein the spring constant control means is a spring of the suspension spring on the inner wheel side of the swing when the vehicle is in a turning state. The suspension controller is configured to set the constant higher than the spring constant of the suspension spring on the side of the turning outer wheel (structure of claim 1), or the main air chamber and the sub air chamber, and these two. A variable spring constant air spring with a first control valve for controlling communication between the chambers A suspension control device for a vehicle in which a suspension is provided for each wheel, and a passage means for mutually connecting the sub air chambers of the left and right wheels, a second control valve for controlling communication between the passage means, and The vehicle has a turning state detecting means for detecting a turning state of the vehicle, a vehicle speed detecting means for detecting a vehicle speed, and a control means for controlling the first and second control valves, wherein the control means does not turn the vehicle. The first and second control valves are kept open when the vehicle is in a non-high vehicle speed state, and the first control valve is opened when the vehicle is in a non-turning state and a high vehicle speed state. While maintaining the second control valve in a closed state, when the vehicle is in a turning state, the first control valve on the turning inner wheel side is kept closed and the first control valve on the turning outer wheel side is kept closed. The control valve of the It is achieved by the suspension control apparatus characterized by being configured to maintain the closed state the control valve (the third aspect).

According to the present invention, in order to effectively achieve the above object, in the structure of claim 1, the suspension of each wheel has a shock absorber with a variable damping force, and the suspension control is performed. The apparatus has damping force control means for controlling the damping force of the shock absorber, and the damping force control means controls the damping force of the shock absorber on the inner wheel side of turning when the vehicle is in a transient turning state to prevent the vehicle from turning. It is configured to be set higher than the hour (configuration of claim 2).

[0008]

According to the above-mentioned structure of the present invention, when the vehicle is in a turning state, the spring constant of the suspension spring on the turning inner wheel side is set higher than the spring constant of the suspension spring on the turning outer wheel side. The amount of extension of the suspension on the side (upward displacement of the vehicle body) becomes smaller than the amount of contraction of the suspension on the outer wheel side of the turning (downward displacement of the vehicle body), and as a result, the height of the center of gravity of the vehicle body during turning is increased. As a result, the turning performance of the vehicle is improved.

In particular, according to the second aspect of the invention, when the vehicle is in the transient turning state, the damping force of the shock absorber on the turning inner wheel side is set to be higher than that when the vehicle is not turning. The amount of extension of the suspension on the inner wheel side is further effectively reduced, which further reduces the height of the center of gravity of the vehicle body during turning.

According to the third aspect of the invention, when the vehicle is in the non-turning state and the non-high vehicle speed state, the auxiliary air chambers of the left and right wheels are connected to each other and are connected to the main air chambers of the respective wheels. Since the sub air chamber is connected in communication, the spring constant of each air spring is maintained at a sufficiently low value to ensure good ride comfort of the vehicle, and when the vehicle is in a non-turning state and a high vehicle speed state, Since the communication between the sub air chambers of the wheels is blocked and the communication state between the main air chamber and the sub air chamber of each wheel is maintained, the spring constant of each air spring is maintained at a medium value, As a result, good steering stability of the vehicle at high vehicle speed is ensured, communication between the left and right sub air chambers is cut off when the vehicle is in a turning state, and the main air chamber on the turning inner wheel side and the sub air chamber The communication with the air chamber is cut off and the turning outer wheel side Since the communication state between the main air chamber and the sub air chamber is maintained, the spring constant of the air spring on the turning inner wheel side is controlled to a high value and the spring constant of the air spring on the turning outer wheel side is controlled to a medium value. Claim 1 by this
As in the case of the above configuration, the turning performance of the vehicle is improved by lowering the height of the center of gravity of the vehicle body when the vehicle turns.

[0011]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing one embodiment of a suspension control device according to the present invention applied to an air suspension equipped with a damping force variable shock absorber.

In FIG. 1, 10FR, 10FL, 10RR, 1
0RL is front right wheel 12FR, left front wheel 12FL, right rear wheel 1
2RR, an air spring provided integrally with the shock absorbers 14FR, 14FL, 14RR, 14RL of variable damping force corresponding to the left rear wheel 12RL are shown. The air springs 10FR, 10FL, 10RR, and 10RL cooperate with the corresponding shock absorbers, and the volume of the main air chamber 16F is variable.
R, 16FL, 16RR and 16RL are defined, and sub-air chambers 18FR, 18FL, 18RR and 18RL having a constant volume are defined.

In the partition between the main air chamber and the sub air chamber of each air spring, each wheel control valve as a first control valve for controlling the communication between the corresponding main air chamber and the sub air chamber. 20FR, 20FL, 20RR, 20RL are provided. The sub air chambers for the left and right front wheels and the left and right rear wheels are provided with conduits 22
Connected to each other by F and 22R, the conduit 22F
And 22R, common control valves 24F and 24 as second control valves for controlling the communication of the corresponding conduits, respectively.
R is provided.

In the illustrated embodiment, each wheel control valve 20F
R, 20FL, 20RR, and 20RL are normally-open type on-off valves, while common control valves 24F and 24R are normally-closed type on-off valves. When these control valves are opened and closed, the state of communication between the main air chamber and the sub air chamber and the state of communication between the left and right sub air chambers are controlled, and as a result, the effective volume of the air chamber of each air spring is controlled. As shown in Table 1 below for the left and right front wheels, the spring constants of the air springs for each wheel are divided into three levels, "super soft", "normal", and "hard", in five combinations. Controlled.

In Table 1, "=" indicates that the corresponding air chambers are in the state of being connected to each other. The relationship between the opening and closing of each control valve on the rear wheel side, the communication of the air chamber, and the spring constant of the air spring is also the same as in Table 1 below.

[0017]

[Table 1] Control valve 20FR 20FL 24F Air chamber communication spring constant Case 1 Open Open 16FR = 18FR = 16FL = 18FL Super soft Case 2 Open Open Closed 16FR = 18FR, 16FL = 18FL Normal Case 3 Closed Closed − − − −−− Hard Case 4 Open Open Closed 16FL = 18FL Right Hard, Left Normal Case 5 Open Closed 16FR = 18FR Right Normal, Left Hard

Particularly in the case 1, since the main air chamber and the sub air chamber of each air spring are connected to each other and the sub air chambers of the left and right wheels are connected to each other, the spring constant of each air spring. Is about 1/2 of the normal case,
As a result, as shown in FIG. 4, the sprung resonance point Fbos
Is about 70% of the resonance point Fbon in the normal case, and the vibration gain on the spring in the frequency range of 0 to 5 Hz is greatly reduced, which greatly improves the riding comfort of the vehicle. To do.

Although not shown in detail in FIG. 1, the shock absorbers 14FR, 14FL, 14RR, 14RL have a damping force control valve in the body of the piston, and the damping force control valve is provided at the upper end of the piston rod. Actuator 26FR,
By being controlled by 26FL, 26RR, and 26RL, the damping force is "high", as shown in FIG.
It is designed to be increased / decreased in three levels of "medium" and "low". The damping force control valve and the actuator may have any conventionally known structure.

Each wheel control valve 20FR to 20RL, common control valve 2
4F and 24R and actuators 26FR to 26RL are provided on the vehicle body in correspondence with the vehicle speed V detected by the vehicle speed sensor 28, the steering angle θ detected by the steering angle sensor 30 when the right turn direction is positive, and the wheels. Vertical acceleration sensor 32F
The electronic control unit 34 controls the vehicle body based on vertical acceleration Gi (i = FR, FL, RR, RL) detected by R, 32FL, 32RR, and 32RL as described later.

As shown in FIG. 2, the electronic control unit 3
4 has a microcomputer 35. The microcomputer 30 may have a general configuration as shown in FIG. 2, and includes a CPU 36, a ROM 38,
It has a RAM 40, an input port device 42, and an output port device 44, which are connected to each other by a bidirectional common bus 46. The input port device 42 includes a vehicle speed sensor 28, a steering angle sensor 30, and a vertical acceleration sensor 32.
A signal indicating the vehicle speed V, a signal indicating the steering angle θ, and a signal indicating the vertical acceleration Gi of the vehicle body are input from FR to 32RL.

The input port device 42 appropriately processes the signal input thereto, and in accordance with the instruction of the CPU 36 based on the program stored in the ROM 38, the CPU and the RAM.
The processed signal is output to 40. R
The OM 38 stores the control program shown in FIG. The CPU 36 is designed to perform various calculations and signal processing based on the control program shown in FIG. 3 as described later. The output port device 44 outputs control signals to the respective wheel control valves 20FR to 20RL via the drive circuits 48FR to 48RL and outputs control signals to the common control valves 24F and 24R via the drive circuits 50F and 50R in accordance with the instruction of the CPU 36. Then, the control signal is output to the actuators 26FR to 26RL via the drive circuits 52FR to 52RL.

Next, the control of the spring constant of the air spring and the damping force of the shock absorber in the illustrated embodiment will be described with reference to the flow chart shown in FIG. The control according to the flowchart shown in FIG. 3 is started by closing an ignition switch (not shown).

First, in step 10, the detection result detected by each sensor is read, and in step 20, it is judged whether or not the vehicle speed V exceeds a reference value Vc (a positive constant). That is, it is determined whether or not the vehicle is in a high vehicle speed state. If a negative determination is made, the process proceeds to step 70, and if an affirmative determination is made, the control valves are set to the case 2 in Table 1 in step 30. As a result, the spring constant of the air spring of each wheel is controlled normally.

In step 40, the vertical acceleration G of the vehicle body
By integrating i, the vertical velocity Vi of the vehicle body of the portion corresponding to each wheel is calculated, and it is determined whether or not the absolute value of the vertical velocity Vzi is less than the reference value Ve (a positive constant). When a positive determination is made, the damping force of the corresponding shock absorber is controlled to a low damping force in step 50, and when a negative determination is made, the corresponding damping force of the shock absorber is medium. Controlled by damping force. Incidentally, steps 40 to 60 are individually executed for each wheel.

In step 70, it is judged whether or not the absolute value of the steering angle θ exceeds the reference value θc (a positive constant), that is, whether or not the vehicle is in a turning state, and the vehicle turns. If it is determined that the vehicle is in the state, the process proceeds to step 150. If it is determined that the vehicle is in the straight traveling state, the control valves are set to the case 1 in Table 1 in step 80. It is controlled, and thereby the spring constant of the air spring of each wheel is super-softly controlled.

In step 90, the vertical accelerations VFR and VFL of the vehicle body on the front wheel side are calculated by integrating the vertical accelerations GFR and GFL of the vehicle body on the front wheel side. Of these, the larger absolute value is calculated. It is set as the vertical speed Vfh of the vehicle body on the front wheel side, and it is determined whether or not the absolute value of the vertical speed Vfh is less than the reference value Vfc (a positive constant). Step 9
If a positive determination is made in step 0, the damping force of the shock absorbers of the left and right front wheels is controlled to a low damping force in step 100, and if negative determination is made, step 11
At 0, the damping forces of the left and right front wheel shock absorbers are controlled to medium damping forces.

In step 120, the vertical accelerations VRR and VRL of the vehicle body on the rear wheel side are calculated by integrating the vertical accelerations GRR and GRL of the vehicle body on the rear wheel side. A value is set as the vertical speed Vrh of the vehicle body on the rear wheel side, and it is determined whether or not the absolute value of the vertical speed Vrh is less than the reference value Vrc (a positive constant). When a positive determination is made in step 120, step 13
At 0, the damping force of the shock absorbers of the left and right rear wheels is controlled to a low damping force, and when a negative determination is made, the damping force of the shock absorbers of the left and right rear wheels is controlled to a medium damping force at step 140. .

In step 150, the steering angular velocity θd is calculated as a time differential value of the steering angle θ, and
Whether or not the absolute value of the steering angular velocity θd exceeds the reference value θdc (a positive constant), that is, whether or not the vehicle is in a very sharp turning state, is determined, and the vehicle is not turning very rapidly. When it is determined that the state is present, step 18 is performed.
0, and when it is determined that the vehicle is in a very sharp turning state, the control valves are controlled as shown in Case 3 of Table 1 in step 160, whereby the springs of the air springs of the respective wheels are controlled. The constant is controlled hard, and in step 170, the damping force of the shock absorber of each wheel is controlled to a high damping force.

In step 180, it is determined whether the steering angle θ is positive, that is, whether the vehicle is turning right, and it is determined that the vehicle is turning right. If so, the routine proceeds to step 240, and if it is determined that the vehicle is in the left turning state, then at step 190, the control valves are controlled as shown in case 4 of Table 1, whereby the air in the front and rear right wheels is controlled. The spring constant of the spring is hard-controlled, and the spring constants of the air springs of the front and rear left wheels are normally controlled.

In step 200, the front and rear left wheel shock absorbers are kept waiting for several seconds while being controlled to a high damping force. In step 210, the front and rear left wheel vertical acceleration Gi (i = FL). , RL) is integrated to calculate the vertical velocity Vi of the front and rear left wheels of the vehicle body, and it is determined whether or not the absolute value of the vertical velocity Vi is less than a reference value Ve (a positive constant). If a positive determination is made in step 210, the damping force of the corresponding shock absorber of the left front wheel or the left rear wheel is controlled to a low damping force in step 220, and if a negative determination is made, step 2
At 30, the damping force of the corresponding shock absorber of the left front wheel or the left rear wheel is controlled to the medium damping force.

In step 240, the spring constants of the air springs of the front and rear left wheels are hard-controlled by controlling the control valves as shown in case 5 of Table 1, and the spring constants of the air springs of the front and rear right wheels are controlled. Is controlled normally. In step 250, the damping force of the shock absorbers for the front and rear right wheels is kept for several seconds while being controlled to a high damping force. The waiting time in steps 200 and 250 is set to a value at least equal to the transient turning time in the normal turning of the vehicle.

In step 260, the vertical accelerations Gi (i = FR, RR) of the front and rear right wheels of the vehicle body are integrated to calculate the vertical speed Vi of the front and rear right wheels of the vehicle body.
It is determined whether or not the absolute value of i is less than the reference value Ve. When a positive determination is made in step 260, the damping force of the corresponding shock absorber of the right front wheel or the right rear wheel is controlled to a low damping force in step 270,
When a negative determination is made, in step 280, the damping force of the corresponding shock absorber of the right front wheel or the right rear wheel is controlled to the medium damping force. Incidentally, steps 210 to 230
And steps 260 to 280 are individually executed for the front and rear left wheels and the front and rear right wheels, respectively.

Thus, according to the illustrated embodiment, if the vehicle is traveling straight at low and medium speeds, step 20
Yes determination is made in steps 70 and 70, the spring constants of the air springs 10FR to 10RL are controlled to super soft in step 80, and the front and rear shock absorbers of the shock absorbers in steps 90 to 140 are controlled. The damping force is controlled to a low damping force or a medium damping force according to the vertical speed of the vehicle body on the front wheel side and the rear wheel side, respectively, which ensures good riding comfort of the vehicle and prevents the wheels from bumping the road surface. The vibration of the vehicle body when riding over is effectively dampened.

If the vehicle is traveling at a high speed, a yes determination is made in step 20, and the spring constant of each air spring is controlled to normal in step 30.
Further, in steps 40 to 50, the damping force of each shock absorber is controlled to be a low damping force or a medium damping force according to the vertical speed of the corresponding vehicle body, whereby good riding comfort and steering stability of the vehicle are secured. To be done.

If the vehicle is in a very sharp turning state, a yes determination is made in step 150,
In step 160, the spring constant of each air spring is hard-controlled, and in step 170, the damping force of each shock absorber is controlled to a high damping force, which allows the vehicle to move during a very sudden turning of the vehicle. The steering stability of is secured.

Further, when the vehicle is in a turning state that is not very abrupt, the spring constant of the air spring on the turning inner wheel side is hard controlled and the spring constant of the air spring on the turning outer wheel side is controlled in step 190 or 240. Controlled to normal. As shown in FIG. 6, when the spring constants K1 of the left and right air springs 100L and 100R are not increased or decreased even when the vehicle is turning, the strokes of the left and right suspensions caused by the centrifugal force F acting on the vehicle body 102. The magnitudes of the quantities -x and + x are substantially the same, which causes a roll in the vehicle body, and the height Hg of the center of gravity of the vehicle body in that case is substantially the same as when the vehicle is in a straight traveling state.

On the other hand, according to the illustrated embodiment, the spring constant of the air spring 100R on the turning inner wheel side is, for example, K1.
Since the stroke amount + a of the suspension on the turning inner wheel side becomes smaller than the stroke amount −b of the suspension on the turning outer wheel side −b, the center of gravity height Hgs of the vehicle body is increased to K2. By making it smaller than the high Hg, the rolling moment acting on the vehicle body can be reduced, the rolling amount of the vehicle body can be reduced, and the turning performance of the vehicle can be improved.

Further, in the above-mentioned conventional suspension control device, in order to improve the turning performance, compressed air is supplied to and discharged from the air chambers of the left and right air springs when the vehicle turns, so that a large amount of energy is consumed. Will end up. On the other hand, according to the illustrated embodiment, it is not necessary to supply and discharge the compressed air even when the vehicle turns, so that the energy consumption can be significantly reduced as compared with the conventional suspension control device. .

Also according to the illustrated embodiment, step 20
At 0 or 250, the damping force of the shock absorber on the turning inner wheel side is controlled to a high damping force at least during the transient turning state, and therefore, the extension stroke amount of the suspension on the turning inner wheel side when the vehicle is in the transient turning state. Is further smaller than the contraction stroke amount of the suspension on the turning outer wheel side, which also reduces the height of the center of gravity of the vehicle body during turning of the vehicle and improves the turning performance of the vehicle.

In both cases of turning left and turning right,
During the steady turn after the transient turn, steps 210 to 230 or steps 260 to 280 are executed to control the damping force of each shock absorber to a low damping force or a medium damping force according to the vertical speed of the vehicle body. .

In the above-mentioned embodiment, the damping force of each shock absorber is controlled in three steps, but the damping force of the shock absorber is set in four steps or more depending on the running condition of the vehicle. It may be controlled in multiple stages, and the shock absorber of the suspension to which the present invention is applied may be a shock absorber having a constant damping force (damping coefficient).

In the above embodiment, each wheel control valve 2
0FL to 20FL are normally open / closed valves, and the common control valve 24
F and 24R are normally closed on-off valves, but each wheel control valve may be a normally closed on-off valve and the common control valve may be a normally open control valve.

Further, in the above embodiment, the air suspension is a passive air suspension, but the air suspension controlled by the suspension control device of the present invention may be an active air suspension. At the time of turning, compressed air is supplied to the air chamber of the air spring on the outer wheel side of the turning, and compressed air is discharged from the air chamber of the air spring on the inner wheel side of the turning, which further improves the steering stability of the vehicle during turning of the vehicle. It may be configured to be further improved.

Although the present invention has been described in detail above with reference to specific embodiments, the present invention is not limited to such embodiments, and other various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art that it is possible.

[0046]

As is apparent from the above description, according to the structure of claim 1 of the present invention, when the vehicle is in a turning state, the spring constant of the suspension spring on the turning inner wheel side is equal to that of the suspension spring on the turning outer wheel side. Since it is set higher than the spring constant, the amount of extension of the suspension on the turning inner wheel side (the amount of upward displacement of the vehicle body) is made smaller than the amount of contraction of the suspension on the outer turning wheel side (the amount of downward displacement of the vehicle body), As a result, the center of gravity of the vehicle body during turning can be lowered to improve the turning performance of the vehicle. Particularly, according to the configuration of claim 2, when the vehicle is in the transient turning state, the shock absorber of the turning inner wheel side Since the damping force is set higher than when the vehicle is not turning, the extension amount of the suspension on the turning inner wheel side during transient turning is further effectively reduced. Furthermore it is possible to further improve the vehicle turning performance and still further reduces the more the vehicle body center of gravity height when turning.

According to the third aspect of the present invention, when the vehicle is in the non-turning state and the non-high vehicle speed state, the sub air chambers of the left and right wheels are connected to each other and are connected to each other, and the main air chambers of the respective wheels are connected. Since it is connected to the sub air chamber, the spring constant of each air spring can be maintained at a sufficiently low value to ensure good riding comfort of the vehicle, and the vehicle is in a non-turning state and a high vehicle speed state. , The communication between the sub air chambers of the left and right wheels is blocked, and the communication between the main air chamber and the sub air chamber of each wheel is maintained, so set the spring constant of each air spring to a medium value. Therefore, good steering stability of the vehicle at high vehicle speed can be ensured, and when the vehicle is in a turning state, the communication between the left and right auxiliary air chambers is blocked and the turning inner wheel is Communication between the main air chamber and the sub air chamber on the side Since the communication between the main air chamber and the sub air chamber on the outer turning wheel side is maintained, the spring constant of the air spring on the inner turning wheel side is controlled to a high value, and the spring constant of the air spring on the outer turning wheel side is set to a medium value. By controlling the value of the above value, the height of the center of gravity of the vehicle body at the time of turning of the vehicle can be reduced as in the case of the structure of claim 1, so that the turning performance of the vehicle can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a suspension control device according to the present invention applied to an air suspension equipped with a variable damping force type shock absorber.

2 is a block diagram showing one embodiment of the electronic control unit shown in FIG. 1. FIG.

FIG. 3 is a flowchart showing a control routine of a spring constant of an air spring and a damping force of a shock absorber.

FIG. 4 is a graph showing vibration gains on springs when the sub air chambers of the left and right air springs are not in communication (broken line) and are in communication (solid line).

FIG. 5 is a graph showing a damping force characteristic of a shock absorber.

FIG. 6 is an explanatory diagram showing changes in the height of the center of gravity of the vehicle body when the spring constant of the air spring is not changed during turning of the vehicle (A) and when the spring constant of the air spring of the turning inner wheel is increased (B). .

[Explanation of symbols]

 10FR to 10RL ... Air springs 14FR to 14RL ... Shock absorbers 16FR to 16RL ... Main air chamber 18FR to 18RL ... Sub air chamber 20FR to 20RL ... Each wheel control valve 24F, 24R ... Common control valve 26FR to 26RL ... Actuator 28 ... Vehicle speed sensor 30 ... Steering angle sensor 32FR-32RL ... Vertical acceleration sensor 34 ... Electronic control device

Claims (3)

[Claims] 1. A suspension control device for a vehicle in which a suspension having a suspension spring with a variable spring constant is provided for each wheel, and a turning state detecting means for detecting a turning state of the vehicle and a spring constant of the suspension spring are set. And a spring constant control means for controlling the spring constant control means, wherein the spring constant control means sets the spring constant of the suspension spring on the turning inner wheel side to be higher than the spring constant of the suspension spring on the turning outer wheel side when the vehicle is in a turning state. A suspension control device configured to perform. 2. The suspension control device according to claim 1, wherein the suspension of each wheel has a shock absorber with a variable damping force, and the suspension control device controls damping force of the shock absorber. The damping force control means is configured to set the damping force of the shock absorber on the turning inner wheel side higher when the vehicle is in a transient turning state than when the vehicle is not turning. Suspension control device. 3. A vehicle in which a suspension having an air spring with a variable spring constant having a main air chamber and a sub air chamber and a first control valve for controlling communication between these two chambers is provided for each wheel. A suspension control device, a passage means for mutually connecting the sub air chambers of the left and right wheels, a second control valve for controlling communication between the passage means, and a turning state detecting means for detecting a turning state of the vehicle And a vehicle speed detecting means for detecting a vehicle speed, and a control means for controlling the first and second control valves, wherein the control means is configured to operate when the vehicle is in a non-turning state and a non-high vehicle speed state. The first and second control valves are kept open, and when the vehicle is in the non-turning state and the high vehicle speed state, the first control valve is kept open and the second control valve is closed. Keep valve state,
When the vehicle is in a turning state, the first control valve on the turning inner wheel side is kept closed, and the first control valve on the turning outer wheel side is kept open and the second control valve is turned on. The suspension control device is configured to maintain the valve closed.