JPH0891034A - Air suspension device for vehicle - Google Patents

Abstract

PURPOSE: To carry out the stable attitude control by controlling the produced car body vibration positively and effectively by varying the spring constant in a pseudo form by varying the internal pressure of an air spring. CONSTITUTION: The steering angular speed α is calculated by differentiating the read-out steering angle θ signal, and the extension/contraction quantity δLH of the rod 32 of an extension/contraction mechanism 35 of the left side wheel of a vehicle and the extension/contraction quantity δRH of the rod 32 of the extension/contraction mechanism 35 of the right side wheel of the vehicle are calculated from the steering angular speed α, and the spring constant is varied in a pseudo form by increasing the internal pressure of an air spring 2 on the side where the car body rolls, and the produced car body vibration is controlled positively and effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle air suspension device, and more particularly to a technique for damping vehicle body vibration when rolling occurs in a vehicle.

[0002]

2. Description of the Related Art Conventionally, suspensions mounted on buses, large trucks, etc. are, for example, Japanese Utility Model Laid-Open No. 64-52920.
Air suspension devices for vehicles, which support the vehicle body by utilizing air elasticity as disclosed in Japanese Laid-Open Patent Publication No. 2-141510 and Japanese Utility Model Laid-Open No. 2-141510, have become mainstream. Here, since the air suspension device for a vehicle uses the air (air) which is a compressible fluid for the air spring, it is possible to secure a superior riding comfort as compared with a normal one using a leaf spring. .

In the case of using such an air suspension device, the spring constant of the air spring can be adjusted by adjusting the air pressure in the air spring, so that the ride comfort of the vehicle is not reduced. Attempts have been made to improve roll controllability. That is,
As shown in FIG. 8, a sub-tank 86 communicating with the inside of the air spring 83 through a pipe 85 is provided, and a solenoid valve 87 as an opening / closing means is provided in the pipe 85, and a solenoid valve 87 is provided according to a vehicle speed and a steering angle. An air suspension device has been proposed in which the spring constant is switched by controlling the opening and closing of the. Incidentally, 84
Is a leveling valve interposed in a communication pipe with an air reservoir tank (not shown) whose pressure is adjusted to a predetermined pressure.

For example, when the vehicle speed is less than a predetermined value or when the vehicle speed is more than a predetermined value but the steering angle is less than the predetermined value, the solenoid valve 87 is opened and the inside of the air spring 83 and the sub-tank 86 are integrated so that the air The air volume inside the spring 83 is substantially increased. In this case, as the air volume is larger, the internal pressure does not increase with respect to the external force, so that the reaction force of the air spring 83 becomes smaller and the spring constant becomes smaller, so that the riding comfort can be improved.

On the other hand, when the vehicle speed is equal to or higher than the predetermined value and the steering angle is equal to or higher than the predetermined value, the solenoid valve 87 is closed to shut off the inside of the air spring 83 from the sub tank 86, thereby substantially reducing the air volume inside the air spring 83. Make it smaller. In this case, the reaction force of the air spring 83 is increased, the spring constant is increased, and the roll can be reduced. Here, the applicant of the present invention has found that the rolling motion of the vehicle body caused by the inertial force due to the centripetal acceleration generated at the time of changing lanes or turning makes the steering direction and the rolling motion direction coincide with each other, while The rolling motion of the vehicle body caused by a sudden crosswind during traveling is sometimes the case where the vehicle body rolls to the leeward side of the crosswind and the case where the vehicle body rolls to the upwind side of the crosswind, and the steering angle In view of the fact that the detected steering angles are not equal to or more than a predetermined angle, the driver is steering the vehicle, and the inertial force due to the centripetal acceleration generated when the lane is changed or when the vehicle turns is acting on the vehicle body. Assuming that rolling occurs, the first switching control means changes the state of each of the air spring and the shock absorber to the hard or soft state based on the steering angle. On the other hand, if the detected steering angle is less than the predetermined angle while the driver is not steering the vehicle and the vehicle body is rolling, it means that the vehicle has been exposed to a sudden crosswind. An air suspension device for a vehicle, which controls the states of the air spring and the shock absorber to be hard or soft based on the lateral acceleration detected by the second switching control means as the rolling motion of the vehicle body that has occurred. It was previously proposed (Japanese Patent Application No. 6-63906).

[0006]

By the way, in these conventional air suspension devices, the vehicle starts to turn in a predetermined direction due to steering and lateral acceleration occurs. As a reaction to this, centrifugal force is exerted on the center of gravity of the vehicle. It acts and this is the roll moment. Then, this roll moment is absorbed by expansion and contraction of the suspension, and a roll angle commensurate with the absorption is generated, so that a roll angle commensurate with the roll rigidity possessed by the air suspension device of the vehicle is generated. . That is, the roll angle generated is not positively reduced.

Further, in the air suspension device having the leveling valve, the roll angle may be delayed in phase due to the action of the leveling valve, and the suspension characteristics may be further deteriorated. .
This is due to the action described below. That is, as the suspension expands and contracts depending on the roll angle, the internal pressure of the air spring decreases and increases, and the leveling valve exhausts.
Turn on the air supply. That is, when the suspension is extended, the leveling valve performs the exhaust operation, and when the suspension is contracted, the leveling valve performs the air supply operation. When the roll angle changes continuously from the left roll to the right roll (or from the right roll to the left roll), additional roll pressure is applied to the internal pressure of the roll in a monotonically increasing or monotonically decreasing manner. Therefore, the roll angle is increased, and the roll angle is increased.

Therefore, in the air suspension device having the leveling valve, the roll of the vehicle body generated by steering or the like cannot be efficiently suppressed, and the drivability may be deteriorated. Therefore, the present invention has been made in view of the conventional problems as described above, and in an air suspension device having a leveling valve, the internal pressure of the air spring is changed to change the spring constant in a pseudo manner. It is an object of the present invention to provide a vehicle air suspension device that positively and effectively suppresses the vehicle body vibration that occurs and enables stable posture control.

[0009]

Therefore, according to the invention of claim 1, at least one air-supporting system is provided between the sprung system of the vehicle and each of the front, rear, left and right unsprung systems. A spring, at least one shock absorber provided between the sprung system and each of the unsprung systems, air supply means for supplying air to the air spring, and air for discharging air from the air spring. Exhaust means,
In a vehicle air suspension device comprising:
The internal pressure increased in synchronization with the steering angle detecting means for detecting the steering angle of the steering wheel, the steering angular velocity calculating means for calculating the steering angular velocity based on the steering angle of the steering, and the steering angular velocity calculated by the steering angular velocity calculating means. Supply / exhaust control means for controlling the air supply means so as to supply air to the side air spring, and controlling the air exhaust means so as to exhaust air from the side air spring having a reduced internal pressure, It is configured to be provided.

[0010] According to a second aspect of the invention, at least one air spring is provided between the sprung system of the vehicle and the unsprung systems on the front, rear, left, and right, and the sprung system, and the sprung system. And at least one shock absorber provided between each of the unsprung systems, and a mechanical leveling valve interposed in an air pipe connecting the air spring and an air supply source for supplying air to the air spring. An air suspension device for a vehicle, wherein when the mechanical leveling valve deviates from a supply / discharge neutral point due to a change in vehicle height, air is supplied to and discharged from the air spring so that the vehicle height can be returned to the original height. A steering angle detecting means for detecting a steering angle of steering, a steering angular velocity calculating means for calculating a steering angular velocity based on the steering angle of the steering, In synchronism with the steering angular velocity calculated by the angular velocity calculation means, air is supplied to the air spring on the side where the internal pressure has increased, and at the same time, the air is exhausted from the air spring on the side where the internal pressure has decreased. A supply / discharge neutral point changing means for changing the supply / discharge neutral point is provided.

According to a third aspect of the present invention, at least one air spring is provided between the sprung system of the vehicle and each of the front, rear, left and right unsprung systems, and the sprung system, and the sprung system. And at least one shock absorber provided between each of the unsprung systems, and a mechanical leveling valve interposed in an air pipe connecting the air spring and an air supply source for supplying air to the air spring. When the vehicle height changes, a rod having one end connected to the unsprung system opens and closes the mechanical leveling valve so that the vehicle height can be returned to the original height. Steering angle detecting means for detecting the steering angle of the steering wheel, steering angular velocity calculating means for calculating the steering angular velocity based on the steering angle of the steering wheel, and steering angle velocity The amount of expansion and contraction of the rod is adjusted so that air is supplied to the air spring on the side where the internal pressure has increased and air is exhausted from the air spring on the side where the internal pressure has decreased in synchronization with the steering angular velocity calculated by the output means. And a control unit for controlling the amount of expansion and contraction.

According to a fourth aspect of the invention, at least one air spring is provided between the sprung system of the vehicle and each of the unsprung systems in the front, rear, left and right, and the sprung system, and the sprung system. And at least one shock absorber provided between each unsprung system, an air supply solenoid valve for supplying air to the air spring, and an air exhaust solenoid valve for discharging air from the air spring. In a vehicle air suspension device comprising :, a steering angle detecting means for detecting a steering angle of a steering wheel; a steering angular velocity calculating means for calculating a steering angular velocity based on the steering angle of the steering; and a steering angular velocity calculating means. In synchronization with the steering angular velocity, the opening control of the solenoid valve for air supply to supply air to the air spring on the side where the internal pressure has increased,
And a supply / exhaust solenoid valve control means for controlling the opening of the air exhaust solenoid valve so as to exhaust air from the air spring on the side where the internal pressure is reduced.

[0013]

According to the invention of claim 1, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means,
The air supply means is controlled so as to supply air to the air spring on the side where the internal pressure is increased, and the air exhaust means is controlled so that the air is discharged from the air spring on the side where the internal pressure is decreased.

That is, for example, by steering to the right, the sprung system rolls to the left. In this case, air is supplied to the left air spring whose internal pressure increases, and air is supplied from the right air spring whose internal pressure decreases. Exhausted. As a result, the spring constant of the air spring is increased in a pseudo manner, and the roll rigidity is increased in a pseudo manner, and it becomes possible to positively and effectively suppress the vehicle body vibration generated in the sprung system. .

As an operation according to the second aspect of the present invention, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means, air is supplied to the air spring on the side where the internal pressure increases and the side where the internal pressure decreases. Since the mechanical supply / discharge neutral point of the mechanical leveling valve is changed to exhaust air from the air spring, the sprung system rolls to the left by steering to the right, for example. Since the air supply / discharging neutral point of the mechanical leveling valve is changed so that the air is supplied to the spring and the air is exhausted from the air spring on the right side where the internal pressure decreases, the operation according to the above-mentioned claim 1 is achieved. The same effect is achieved.

As an operation according to the third aspect of the present invention, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means, air is supplied to the air spring on the side where the internal pressure increases and the side where the internal pressure decreases. Since the expansion and contraction amount of the rod is controlled so that the air is exhausted from the air spring, the sprung system rolls to the left by steering to the right, for example. Is expanded, and the expansion / contraction amount of the rod of the mechanical leveling valve is changed so that the air is exhausted from the air spring on the right side where the internal pressure is reduced. Therefore, the same operation as the operation according to the invention described in claim 1 is performed. Is played.

As the operation according to the fourth aspect of the present invention, the sprung system rolls to the left by steering to the right, for example, but in this case, the left and right air springs whose internal pressure is increased by the supply / exhaust solenoid valve control means. By controlling the opening of the solenoid valve for air supply so as to supply air to the air and controlling the opening of the solenoid valve for exhausting air so that air is exhausted from the air spring on the right side where the internal pressure decreases, The same operation as the operation according to the invention of claim 1 is achieved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows an air suspension device for one wheel of a vehicle. That is, in this figure, an air spring 2 and a shock absorber 7 incorporating a damping force switching mechanism are provided between a vehicle body 20 as an unsprung body of a vehicle and a tire 1 as an unsprung body. A communication passage 22 is provided between the inside of the air spring 2 and the sub tank 5 via a spring constant switching valve 6 which is an electromagnetic valve for switching the spring constant.
Is communicated by.

Further, the air reservoir tank 25 for storing compressed air and the air spring 2 are provided by a supply / exhaust passage 21 having a leveling valve 4 for supplying and discharging compressed air to and from the air spring 2. Communicated.
Further, a mechanical leveling valve 4 is provided in a pipe 21 that connects the air reservoir tank 25, which stores compressed air, and the inside of the air spring 2 to the air reservoir tank 25.
The air from is supplied to and discharged from the mechanical leveling valve 4.

The mechanical leveling valve 4 is provided with a single operating lever 31. When this lever 31 rotates, for example, clockwise, compressed air is discharged from the inside of the air spring 2 and when it rotates counterclockwise. It is being supplied. The rod 32 is used to rotate the operating lever 31.
Is provided, and its upper end a is pivotally attached to the free end side of the operating lever 31, and its lower end b is pivotally attached to the free end side of the axle-side member 33.

Further, as a structure according to the present invention, a rod
An extension / contraction mechanism 35 for interposing the rod 32 to be extendable / contractible is interposed in the rod 32 so that the entire length of the rod 32 is variable. As the expansion / contraction mechanism 35, as shown in FIG. 2, a casing 36 whose lower end portion forms a lower rod 34, and the casing 36
A rack 38 that moves in the pinion 37 while meshing with the pinion 37, and the upper end portion forms the upper rod 33;
And a step motor 39 for rotating the.

When the entire length of the rod 32 is changed by the extension / contraction mechanism 35, the neutral point of the operating lever 31 in the rotating direction is changed. That is, the rod 32 and the expansion / contraction mechanism 35 of the rod 32 constitute a supply / discharge neutral point changing means for changing the supply / discharge neutral point of the mechanical leveling valve 4. Further, a control unit 9 having a built-in microcomputer receives a changeover M signal from a mode changeover switch 10 described later, a steering angle θ signal from a steering angle sensor 11 and a vehicle speed V signal from a vehicle speed sensor 17.

Then, in the control unit 9, the internal pressure is increased in synchronization with the steering angular velocity calculating means for calculating the steering angular velocity α based on the steering angle θ signal and the steering angular velocity α calculated by the steering angular velocity calculating means. The air supply / discharging neutral point changing means for changing the air supplying / discharging neutral point of the mechanical leveling valve 4 so that the air is supplied to the air spring 2 on the side and the air is exhausted from the air spring 2 on the side where the internal pressure is reduced. The air supply / exhaust control means for controlling the air supply / exhaust means for supplying / exhausting the air from the spring 2) is provided by software, and the step motor 39 for moving the rack 38, the The actuator 8 of the damping force switching mechanism of the spring constant switching valve 6 and the shock absorber 7 is a control unit with a built-in microcomputer. Switching control is performed by a control signal output from the switch 9, and expansion / contraction control of the entire length of the rod 32, opening / closing control of the communication passage 22, and damping force switching control of the shock absorber 7 are performed.

FIG. 3 is a detailed control block diagram of an embodiment according to the present invention. The changeover M signal output from the mode changeover switch 10 is transmitted through the mode signal input means 51.
A signal output from the vehicle speed sensor 17 is sent to the control means 56 via the vehicle speed signal input means 52, and a signal output from the steering angle sensor 11 is sent to the control means 56 via the steering angle signal input means 53 and the steering angle signal differentiating means 54. Is entered.

The control signal output from the control means 56 is applied to the spring constant switching valve 6 via the spring constant switching valve switching signal output means 57 and to the damping force of the shock absorber 7 via the shock absorber switching signal output means 58. The stepping motor 39 of the expansion / contraction mechanism 35 is connected to the actuator 8 of the switching mechanism via the leveling valve drive rod expansion / contraction signal output means 59.
Are input respectively.

Next, the control contents according to this embodiment will be described. The flow chart shown in FIG. 4 shows the contents of the expansion / contraction control of the expansion / contraction mechanism 35 and the switching control of the spring constant switching valve 6 and the actuator 8 of the damping force switching mechanism of the shock absorber 7 by the control unit 9.
It is executed only when 10 switching positions are switched to the auto mode.

In step 1 (abbreviated as S1 in the figure; the same applies hereinafter), the vehicle speed V signal is read from the vehicle speed sensor 17. In step 2, the vehicle speed V is determined whether more than a predetermined value V _REF, when a V ≧ V _{RE F,} the vehicle with the steering starts to pivot in a predetermined direction, the lateral acceleration is generated In this case, as a reaction, a large centrifugal force acts on the vehicle body center of gravity, resulting in a roll moment, which may cause a large rolling. It is necessary to actively cope with this, and the process proceeds to step 3. .

In step 3, the steering angle θ signal from the steering angle sensor 11 is read. There are cases where the vehicle is steered to the right and cases where the vehicle is steered to the left. Therefore, the steering angle θ signal is a signal having positive and negative signs. Here, in the present embodiment, the case where the vehicle is steered to the right side (when the left side of the vehicle rolls down is generated) is positive, and the case where the vehicle is steered to the left side (when the rolling side is lowered to the right side of the vehicle) is set negative.

In step 4, the steering angular velocity α is calculated by differentiating the steering angle θ signal read in step 3. In step 5, referring to a map stored in advance, the amount of expansion / contraction δ _LH of the rod 32 of the extension / contraction mechanism 35 for the wheel on the left side of the vehicle and the rod 32 of the extension / contraction mechanism 35 for the wheel on the right side of the vehicle are calculated based on the steering angular velocity α. Calculate the expansion / contraction amount δ _RH of.

The map relating to step 5 will now be described. In the map, the characteristic line is a characteristic line showing the relationship between the expansion / contraction amount δ _LH of the left wheel and the steering angular velocity α.
Further steering to the right causes rolling of the left side of the vehicle to lower. At this time, the steering angular velocity α
Is detected as α> 0, and at this time, the expansion / contraction amount δ _{LH such} that δ _LH > 0 is calculated. Here, when δ _LH > 0, the rod 32
As the rod 32 moves upward, the operating lever 31 of the mechanical leveling valve 4 is rotated counterclockwise, and compressed air is supplied into the air spring 2 to raise the vehicle height on the left side of the vehicle. Acts like. Also,
When the rolling to the left of the vehicle occurs due to the decrease in steering to the right (actually, steering to the left), the steering angular velocity α is detected as α <0, and at this time δ _LH <0 The quantity δ _LH is calculated. Where δ _LH <
When it becomes 0, the rod 32 contracts, so that the rod 32 moves downward and the operation lever 31 of the mechanical leveling valve 4 is rotated clockwise, so that compressed air is discharged from the inside of the air spring 2 and the left side of the vehicle is discharged. It acts to lower the vehicle height.

On the other hand, the characteristic line is a characteristic line showing the relationship between the amount of expansion / contraction δ _RH of the right wheel and the steering angular velocity α, and further steering to the left causes rolling of the right side of the vehicle to lower. However, at this time, the steering angular velocity α is α
<Detected as 0, _RH [delta] At this time> 0 becomes stretchable amount [delta] _RH
Is calculated. Here, when δ _RH > 0, the rod 32 extends, so that the rod 32 moves upward and the operating lever 31 of the mechanical leveling valve 4 is rotated counterclockwise, so that compressed air is introduced into the air spring 2. Supply,
It acts to increase the vehicle height on the right side of the vehicle. In addition, steering to the left decreases (actually, steering to the right)
As a result, when rolling occurs in which the right side of the vehicle rises, the steering angular velocity α is detected as α> 0, and at this time δ
_An expansion / contraction amount δ _{RH for RH} <0 is calculated. Where δ _RH <0
Then, since the rod 32 contracts, the rod 32 moves downward, and the operating lever 31 of the mechanical leveling valve 4 is rotated clockwise, so that compressed air is discharged from the inside of the air spring 2 and the vehicle on the right side of the vehicle is discharged. It acts to lower the height.

As is clear from the map of step 5, in this embodiment, when the steering angular velocity α is small, the expansion / contraction amount δ of the rod 32 of the expansion / contraction mechanism 35 is set to 0, and the vehicle height control by the mechanical leveling valve 4 is performed. There is a so-called dead zone that does not occur. Next, at step 6, a correction coefficient K for correcting the expansion / contraction amount δ of the rod 32 of the expansion / contraction mechanism 35 calculated at step 5 is obtained according to the vehicle speed V.

The correction coefficient K is a coefficient that approaches 1.0 as the vehicle speed V increases from V _REF.
When is small, the rapid expansion and contraction of the rod 32 of the expansion and contraction mechanism 35 is suppressed, and stable control is possible. Then, the expansion / contraction amount δ _LH of the rod 32 of the expansion / contraction mechanism 35 for the wheel on the left side of the vehicle and the expansion / contraction amount δ _RH of the rod 32 of the expansion / contraction mechanism 35 for the wheel on the right side of the vehicle calculated in step 5 are corrected by the correction coefficient K, As shown in the following formula, the rod of the telescopic mechanism 35 of each wheel
The expansion / contraction amount δ of 32 is calculated.

Δ _LH = K × δ _LH δ _RH = K × δ _{RH In} step 7, the expansion amount δ of the rod 32 of the expansion mechanism 35 of each wheel calculated in step 6 is applied to the step motor 39 of each expansion mechanism 35. It is output and the length of the entire rod 32 of each mechanical leveling valve 4 is expanded and contracted.

In step 8, the spring constant switching valve 6 is closed to switch the spring constant to a large value, and the air spring 2 is set to a hard value. In step 9, the actuator 8 of the damping force switching mechanism of the shock absorber 7 is switched and controlled, and the shock absorber 7 is switched to the hard type (large damping force). On the other hand, when it is determined in step 2 that V <V _REF , even if the vehicle starts to turn in a predetermined direction due to steering and lateral acceleration occurs, the vehicle speed is low, and therefore a large centrifugal force is exerted on the vehicle body center of gravity. Assuming that there is no possibility that a large rolling will occur due to a small roll moment, the step 10
Proceed to.

In step 10, rolling does not occur in which the right side or the left side of the vehicle moves up and down, so
Since it is not necessary to rotate the operation lever 31 of the mechanical leveling valve 4 in the clockwise direction and the counterclockwise direction, it is not necessary to control the expansion / contraction amount δ of the rod 32 of the expansion / contraction mechanism 35 of each wheel. Extension amount of rod 32 of mechanism 35 δ
Be δ = 0.

In step 11, a value of δ = 0 is output as the expansion / contraction amount, but since the step motor 39 of each expansion / contraction mechanism 35 does not actually move, the total length of the rod 32 of each mechanical leveling valve 4 is It is maintained as it is. Then, in step 12, the spring constant switching valve 6 is closed to switch the spring constant to a small value to set the air spring 2 to be soft, and in step 13, the actuator 8 of the damping force switching mechanism of the shock absorber 7 is switched. By controlling and switching the shock absorber 7 to soft (small damping force), riding comfort is secured.

Now, the operation of this embodiment will be described with reference to the time chart shown in FIG. In this figure, it is assumed that the vehicle speed V is high to some extent and the above-mentioned control is performed. Unless otherwise specified, the solid line shows the operation in the past and the dotted line shows the operation according to the present embodiment. Figure 5
As in (1), the driver operates the steering wheel to the right from the predetermined time ta and then steers to the left. Therefore, the steering angle θ increases positively from a predetermined time ta, reaches a maximum at time tb, and then starts to decrease, becomes 0 at time tc, decreases negatively, and increases after reaching a minimum at time td. At time t
It becomes 0 at e.

Therefore, the steering angular velocity α rises from a predetermined time ta, becomes 0 at the time tb when the steering angle θ reaches its maximum, then decreases, then becomes minimum at time tc, and then increases, and the steering angle θ becomes minimum. It becomes 0 at time td, which changes to positive, increases, and reaches 0 at time te after reaching the maximum value. On the other hand, the vehicle body rolls at a phase substantially equal to the steering angle θ, and a roll angle as shown in FIG. 5B is generated. That is, roll to the left from time ta, and
Roll to the right of c.

At this time, the left air spring 2 is compressed and the internal pressure is increased by rolling the vehicle body to the left from time ta as shown in FIG.
By rolling to the right of c, the pressure is reduced by expansion. At this time, in the conventional mechanical leveling valve 4 on the left side, as shown in FIG. 5 (4), since the vehicle body is depressed from time ta, the operating lever 31 is rotated counterclockwise to compress the compressed air. The air is supplied to the inside of the air spring 2, and the vehicle body extends from the time tc. Therefore, the operation lever 31 rotates clockwise to exhaust the compressed air from the inside of the air spring 2.

Therefore, in the prior art, as shown in FIG. 5 (5), the additional pressure applied to the inside of the air spring 2 is continuously supplied by the mechanical leveling valve 4 from the time ta to the time tc. Continues to be added and turns to exhaust at time tc, so the addition starts to decrease. However, in the present embodiment, as described in step 5 above, the expansion / contraction amount δ _LH of the rod 32 of the expansion / contraction mechanism 35 and the rod 32 of the expansion / contraction mechanism 35 of the right wheel of the vehicle are approximately proportional to the steering angular velocity α. By calculating the expansion / contraction amount δ _RH of, the mechanical leveling valve 4 performs air supply / exhaust so as to be substantially proportional to the steering angular velocity α as shown in FIG. 5 (4). That is, air supply is started from time ta, becomes neutral immediately after time tb, and then exhaust is started,
Exhaust until time td, supply air again, and then at time t
Return to 0 neutral position with e.

Therefore, in this embodiment, as shown in FIG. 5 (5), the additional pressure applied to the inside of the air spring 2 is continuously applied from the time ta to the time tb, and thereafter the amount of the additional pressure decreases. Then, it becomes 0 immediately after the time tc, and becomes an additional pressure on the negative side immediately after the time tc, so that the pressure inside the air spring 2 is reduced. Therefore, as shown in FIG. 5C, the inner pressure of the left air spring 2 is further increased from the time ta as compared with the conventional one, and is further decreased from the time tc as compared with the conventional one.

Therefore, the total value of the internal pressure becomes large, and it becomes difficult for the vehicle body to roll. Therefore, as shown in FIG. 5B, the roll angle to the left side becomes smaller than the time ta and the roll angle to the right side becomes from the time tc. Becomes smaller. That is, in this embodiment, the control unit 9 functions as the expansion / contraction amount control means.

Therefore, in the vehicle air suspension system according to the present embodiment, even if the vehicle body roll caused by steering or the like occurs, the rod 32 of the expansion / contraction mechanism 35 is set to be substantially proportional to the steering angular velocity α. The expansion / contraction amount δ _LH and the expansion / contraction amount δ _RH of the rod 32 of the expansion / contraction mechanism 35 for the right wheel of the vehicle are calculated,
By increasing the internal pressure of the air spring 2 on the side where the vehicle body rolls, the spring constant can be artificially changed to positively and effectively suppress the generated vehicle body vibration. When the control is performed, the suspension characteristics are also hardened, so it is possible to maintain the distance between the lower part of the vehicle body and the ground even when the vehicle changes suddenly.For example, the lower part of the vehicle body may contact the ground. Can be prevented.

Therefore, the present embodiment has an effect that the generated rolls are positively and effectively damped, so that the steering stability of the vehicle can be improved. Further, in the present embodiment, the feeding / discharging neutral point changing means is provided with an expanding / contracting mechanism 35 for varying the entire length of the rod 32, and the step motor 39 is used to change the feeding / discharging neutral point of the mechanical leveling valve 4. The length of the entire rod 32 is fixed, the mechanical leveling valve 4 itself is rotatably held, and the mechanical leveling valve 4 is rotated to rotate the mechanical leveling valve 4. The neutral point may be changed.

As another embodiment according to the present invention, as shown in FIG. 6, an air supply valve 71 and an exhaust valve 72 are arranged in parallel with the mechanical leveling valve 4, and the air supply valve 71 is provided.
Even if the exhaust valve 72 and the exhaust valve 72 are controlled by the supply / exhaust solenoid valve control means provided as software as shown in the time chart of FIG. 7, it is possible to obtain the same operation and effect as the above-mentioned embodiment. Becomes

Since the control is the same as the control of the above-mentioned embodiment, the explanation is omitted. Further, in this embodiment, the orifice 73 provided in the pipe connecting the mechanical leveling valve 4 and the sub tank 5 is for weakening the action of the mechanical leveling valve 4.

[0048]

As described above, according to the invention described in claim 1, air is supplied to the air spring on the side where the internal pressure is increased, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means. As described above, the air supply means is controlled, and the air exhaust means is controlled so that the air is exhausted from the air spring on the side where the internal pressure is reduced, so that the generated roll is positively and effectively damped, so that the vehicle is There is an effect that it is possible to improve the steering stability of the.

According to the second aspect of the present invention, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means, air is supplied to the air spring on the side where the internal pressure has increased and the air pressure on the side where the internal pressure has decreased. Since the mechanical supply / discharge neutral point of the mechanical leveling valve is changed so that air is exhausted from the air spring, the roll that occurs is positively and effectively damped, and it is possible to improve the steering stability of the vehicle. There is an effect that.

According to the third aspect of the present invention, in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means, air is supplied to the air spring on the side where the internal pressure has increased and the air pressure on the side where the internal pressure has decreased. Since the amount of expansion and contraction of the rod is controlled so that air is exhausted from the air spring, the generated roll is positively and effectively damped, so that the steering stability of the vehicle can be improved. There is.

According to the fourth aspect of the present invention, the electromagnetic air for air supply is supplied in synchronization with the steering angular velocity calculated by the steering angular velocity calculating means so as to supply air to the air spring on the side where the internal pressure increases. Even if the valve is controlled to be opened and the air exhaust solenoid valve is controlled to be exhausted so that air is exhausted from the air spring on the side where the internal pressure is reduced, the roll that is generated is positively and effectively damped, and therefore the vehicle There is an effect that it is possible to improve the steering stability of the.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a configuration of a rod expanding / contracting mechanism according to the embodiment.

FIG. 3 is a control block diagram according to the embodiment.

FIG. 4 is a flowchart illustrating the control contents of the above embodiment.

FIG. 5 is a time chart explaining the operation of the above embodiment.

FIG. 6 is a system diagram of another embodiment of the present invention.

FIG. 7 is a time chart explaining the operation of another embodiment of the above.

FIG. 8 is a system configuration diagram of an example of a conventional vehicle air suspension device.

[Explanation of symbols]

 1 Tire 2 Air Spring 4 Mechanical Leveling Valve 5 Sub Tank 6 Spring Constant Switching Valve 7 Shock Absorber 8 Actuator 9 Control Unit 11 Steering Angle Sensor 17 Vehicle Speed Sensor 31 Operation Lever 32 Rod 35 Expansion Mechanism 39 Step Motor

Claims (4)

[Claims] 1. An air spring for supporting at least one sprung system provided between a sprung system of a vehicle and front, rear, left and right unsprung systems; and a sprung system and each unsprung system. At least one shock absorber provided between,
Air supply means for supplying air to the air spring,
A vehicle air suspension device comprising: an air exhaust unit that exhausts air from the air spring; a steering angle detecting unit that detects a steering angle of a steering; and a steering that calculates a steering angular velocity based on the steering angle of the steering. In synchronization with the angular velocity calculation means and the steering angular velocity calculated by the steering angular velocity calculation means, the air supply means is controlled so as to supply air to the air spring on the side where the internal pressure has increased, and the side where the internal pressure has decreased. And an air supply / exhaust control means for controlling the air exhaust means so as to exhaust the air from the air spring. 2. An air spring for supporting at least one sprung system provided between a sprung system of a vehicle and respective unsprung systems in front, rear, left and right, and the sprung system and each unsprung system. At least one shock absorber provided between,
A mechanical leveling valve provided in an air pipe that connects the air spring and an air supply source that supplies air to the air spring is provided, and the mechanical leveling valve deviates from the supply / discharge neutral point due to a change in vehicle height. In an air suspension device for a vehicle in which air is sometimes supplied to and discharged from the air spring so that the vehicle height can return to the original height, steering angle detection means for detecting the steering angle of the steering wheel and steering angle of the steering wheel In accordance with the steering angular velocity calculation means for calculating the steering angular velocity on the basis of the steering angular velocity and the steering angular velocity calculated by the steering angular velocity calculation means, air is supplied to the air spring on the side where the internal pressure increases and the side where the internal pressure decreases. Change the supply / discharge neutral point of the mechanical leveling valve so that the air is exhausted from the air spring. An air suspension device for a vehicle, comprising: a changing unit. 3. An air spring which is provided between at least one sprung system of a vehicle and each of the front, rear, left and right unsprung systems to support the sprung system, and the sprung system and each of the unsprung systems. At least one shock absorber provided between,
A mechanical leveling valve provided in an air pipe connecting the air spring and an air supply source for supplying air to the air spring is provided, and when the vehicle height changes, one end is connected to the unsprung system. In a vehicle air suspension device in which the mechanical leveling valve is opened / closed by a rod so that the vehicle height can be returned to the original height, a steering angle detection means for detecting a steering angle of a steering and a steering angle of the steering based on the steering angle of the steering are detected. The steering angular velocity calculation means for calculating the steering angular velocity and the air spring on the side where the internal pressure decreases while supplying air to the air spring on the side where the internal pressure has increased in synchronization with the steering angular velocity calculated by the steering angular velocity calculation means. And an expansion / contraction amount control means for controlling the expansion / contraction amount of the rod so as to exhaust air from the Air suspension device for vehicles. 4. An air spring, which is provided between at least one sprung system of the vehicle and each of the front, rear, left, and right unsprung systems to support the sprung system, and the sprung system and each of the unsprung systems. At least one shock absorber provided between,
A steering angle of a steering wheel is detected in an air suspension device for a vehicle, comprising: an air supply solenoid valve for supplying air to the air spring; and an air exhaust solenoid valve for exhausting air from the air spring. The steering angle detection means, the steering angular velocity calculation means for calculating the steering angular velocity based on the steering angle of the steering wheel, and the air angular velocity calculated by the steering angular velocity calculation means are synchronized with the steering angular velocity, and air is supplied to the air spring on the side where the internal pressure is increased. A supply / exhaust solenoid valve control means for controlling the opening of the solenoid valve for air supply so as to supply air, and for controlling the opening of the solenoid valve for exhaust air so as to exhaust air from the air spring on the side where the internal pressure is reduced. An air suspension device for a vehicle, wherein: