JP2008080906A - Attitude controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attitude controller for a vehicle, easy in arrangement to the vehicle and properly suppressing rolling motion and pitching motion of the vehicle by stabilizer devices on front and rear sides of the vehicle. <P>SOLUTION: A front wheel side intermittent means (rotary valve F20) and a rear wheel side intermittent means (R20) driven by a fluid are provided on the front wheel side stabilizer device (F10) and the rear wheel side stabilizer device (R10), respectively. When front wheel side stabilizer bars (F11, F12) and rear wheel side stabilizer bars (R11, R12) are driven in the same direction relative to the vehicle, out of the respective two pressure chambers, the pressure chambers at the pressure-increasing side are communicated with each other by a pair of communication passages (30a, 30b), and these are connected by a connection passage (30e). A first opening/closing valve (41) is provided in at least one of the pair of communication passage, a second opening/closing valve (42) is provided in the connection passage and these valves are switched. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle attitude control device, and more particularly to a vehicle attitude control device that can suppress rolling and pitching motions of a vehicle by means of a stabilizer device disposed between left and right wheels at the front and rear of the vehicle.

  In general, a stabilizer device for a vehicle is disposed between left and right wheels of the vehicle, and acts as a torsion spring when a relative displacement difference occurs between suspension strokes between the left and right wheels, thereby suppressing rolling motion of the vehicle. be able to. Furthermore, the following Patent Document 1 is provided with a U-shaped front stabilizer and a rear stabilizer respectively connected to axles of a front wheel and a rear wheel of a vehicle for the purpose of providing a stabilizer device capable of simultaneously preventing rolling and pitching. The front stabilizer is divided into a first part and a second part, the rear stabilizer is divided into a third part and a fourth part, an intermediate link mechanism is provided in the middle of the vehicle, and the stabilizer first The first portion is connected to the fourth rod of the fourth portion via the first rod and the intermediate link mechanism, and the second portion of the stabilizer is connected to the third rod via the second rod and the intermediate link mechanism. A device connected to the third rod of this part has been proposed.

  On the other hand, in Patent Document 2 below, the apparatus described in Patent Document 1 is a conventional technique, and the apparatus relates to the vertical movement of the left front wheel and the right rear wheel, and the vertical movement of the right front wheel and the left rear wheel. Because the movements are related, the number of parts of the rods and levers connecting the front, rear, left and right four wheels increases and the structure becomes complicated, and it becomes difficult to secure a space for arranging these members. It is stated. A vehicle stabilizer device having the following configuration has been proposed for the purpose of effectively balancing vehicle rolling and pitching with a simple and compact structure. That is, it has an intermediate stabilizer that connects the front stabilizer provided between the left and right front wheels and the rear stabilizer provided between the left and right rear wheels, and the intermediate stabilizer is used when the front and rear wheels move up and down in the same phase. There has been proposed a device that does not generate an elastic restoring force without being twisted and generates an elastic restoring force by being twisted when the front and rear wheels move up and down in different phases.

JP 2000-289427 A Japanese Utility Model Publication No. 6-42312

  In each of the stabilizer devices described in Patent Documents 1 and 2, the front stabilizer bar and the rear stabilizer bar of the vehicle are connected by a link mechanism, and the power of an electric motor or the like is used to control torsional force. The force according to the vehicle behavior is used without being used. Such a link mechanism needs to secure a considerable working space, but there are various restrictions when it is mounted on a vehicle, and it is quite difficult to realize. In particular, it is desirable to arrange the parts constituting the link mechanism linearly in consideration of transmission efficiency, cost, etc., but there are engines, transmissions, drive shafts, etc. between the stabilizer bars before and after the vehicle. Therefore, it is extremely difficult to arrange them linearly.

  In addition, when traveling on rough roads, the stabilizer bars on the front and rear sides of the vehicle are often in opposite phases, so if the stabilizer bars on the front and rear sides of the vehicle are connected by an intermediate link mechanism, there is a risk that sufficient tire ground contact properties cannot be obtained. is there. Therefore, when connecting the stabilizer bars in front of and behind the vehicle, it is necessary to consider the influence during driving on a rough road.

  Therefore, the present invention can appropriately suppress the rolling motion and the pitching motion of the vehicle by the front wheel side stabilizer device connected between the front wheels of the vehicle and the rear wheel side stabilizer device connected between the rear wheels of the vehicle. It is an object of the present invention to provide a vehicle attitude control device that can be easily arranged on a vehicle.

  To achieve the above object, according to the present invention, a front wheel side stabilizer device connected between wheels in front of a vehicle and a rear wheel side stabilizer device connected between wheels in the rear of the vehicle are provided. And a first rotating member that is interposed in an intermediate portion of the front wheel side stabilizer bar constituting the front wheel side stabilizer device, and rotates integrally with the front wheel side stabilizer bar, and the first rotating member is rotatable. A first housing that is accommodated and that forms at least two pressure chambers in the circumferential direction with the first rotating member and that is supported by a vehicle body in front of the vehicle is provided, and the two pressure chambers of the first housing include A second rotation that is interposed between the front wheel side intermittent means filled with fluid and an intermediate portion of the rear wheel side stabilizer bar constituting the rear wheel side stabilizer device and rotates integrally with the rear wheel side stabilizer bar. Part And a second housing that rotatably accommodates the second rotating member, forms at least two pressure chambers circumferentially with the second rotating member, and supports the second rotating member on the vehicle body behind the vehicle. Among the two pressure chambers of the rear wheel side intermittent means and the front wheel side intermittent means, each of which is filled with fluid in the two pressure chambers of the second housing. A pair of communication passages for connecting pressure chambers on the side where pressure increases when the wheel side stabilizer bar and the front wheel side stabilizer bar are driven in the same direction with respect to the vehicle, and the pair of communication passages are connected. A first on-off valve that opens and closes the communication path, a second on-off valve that opens and closes the connection path, and the first and second valves. Switching means for switching the on-off valve; Those were.

  Further, according to a second aspect of the present invention, the switching means is connected to the pair of communication paths, and stores an accumulator that contains a part of the fluid sealed in the pair of communication paths, the accumulator and the pair of communication paths. A third and fourth on-off valve interposed between the communication passages and opening and closing the respective communication passages; opening and closing the third and fourth on-off valves; It is preferable that the fluid pressure in each of the two pressure chambers of each of the rear wheel side intermittent means is maintained at a predetermined pressure.

  According to a third aspect of the present invention, the switching means can be configured to control the opening and closing of the first to fourth on-off valves according to at least the traveling state of the vehicle. For example, the switching means may be configured to switch all the first to fourth on-off valves to the closed position when the vehicle is in a turning state. The switching means may be configured to switch all of the first to fourth on-off valves to the open position when the vehicle is on a rough road. Further, as described in claim 6, when the vehicle is in a braking state and a starting state, the first on-off valve is opened and the second to fourth on-off valves are closed. .

  Since this invention is comprised as mentioned above, there exist the following effects. That is, in the vehicle attitude control device configured as described in claim 1, the rear of the two pressure chambers in the fluid-driven front wheel side intermittent means and rear wheel side intermittent means having the above-described configuration is provided. A pair of communication paths that connect the pressure chambers on the side where the pressure increases when the wheel side stabilizer bar and the front wheel side stabilizer bar are driven in the same direction with respect to the vehicle, and a connection path that connects these communication paths And a first on-off valve that opens and closes the communication path, and a second on-off valve that opens and closes the connection path, and switches between the first and second on-off valves. Since it is comprised as mentioned above, it can arrange | position easily with respect to a vehicle and the rolling motion and pitching motion of a vehicle can be suppressed appropriately. In particular, since the communication path can be freely arranged by piping, an empty space at the lower part of the vehicle body can be used effectively. In addition, since the intermittent means uses a fluid, it is possible to suppress the occurrence of abnormal noise and perform posture control smoothly.

  If the switching means is configured as described in claim 2, even if the fluid is thermally expanded, it can be appropriately compensated by the accumulator. Further, for example, even when air is mixed into the fluid during fluid filling, the fluid pressure in the two pressure chambers can be maintained at a predetermined pressure by the accumulator.

  Further, according to the third aspect of the present invention, the front wheel side intermittent means and the rear wheel side intermittent means can be quickly and appropriately controlled in accordance with the traveling state of the vehicle. Can be suppressed appropriately. For example, when configured as described in claim 4, when the vehicle is in a turning state, the torsional force by the front wheel side stabilizer bar and the rear wheel side stabilizer bar can be effectively functioned. According to the fifth aspect of the present invention, when traveling on a rough road, the connection state between the front wheel side stabilizer device and the rear wheel side stabilizer device is released. The influence can be avoided. According to the sixth aspect of the present invention, when the vehicle is in a braking state and a starting state, the torsional force generated by the front wheel side stabilizer bar and the rear wheel side stabilizer bar can be effectively functioned.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 to 3 show the configuration of a vehicle attitude control device according to an embodiment of the present invention. A front wheel side stabilizer device F10 mounted between wheels FR and FL in front of the vehicle and wheels RR in the rear of the vehicle. And a rear wheel side stabilizer device R10 mounted between RL and RL. As shown in the lower right of FIG. 1, the rotational motion around the X axis is based on the coordinate axis fixed to the vehicle with the vehicle longitudinal direction as the X axis, the horizontal direction (lateral direction) as the Y axis, and the vertical direction as the Z axis. Is a rolling motion, a rotational motion about the Y axis is defined as a pitching motion, and a rotational motion about the Z axis is defined as a yawing motion.

  Each stabilizer bar constituting the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 is provided with a rotary valve device, so-called rotary valves F20 and R20, as an intermittent means, at an intermediate portion thereof. Specifically, in the front wheel side stabilizer device F10, the front wheel side stabilizer bar is constituted by the torsion bars F11 and F12, and these are connected via the rotary valve F20. Similarly, in the rear wheel side stabilizer device R10, the rear wheel side stabilizer bar is constituted by the torsion bars R11 and R12, and these are connected via the rotary valve R20. In this embodiment, since the rotary valves F20 and R20 have substantially the same structure, the front wheel-side rotary valve F20 will be described below for the common basic configuration. The front wheel side stabilizer device F10 is attached to the vehicle body (shown by hatching in FIG. 3) by mounts F11c and F12c shown in FIG. 1, and the rear wheel side stabilizer device R10 is similarly attached to the vehicle body by mounts R11c and R12c. The

  In the front wheel side rotary valve F20, a rotor 21 as a rotating member is rotatably accommodated in a housing 22, and the housing 22 is supported by a vehicle body (shown by hatching in FIG. 3). As shown in FIG. 3, the rotor 21 is integrally formed with a pair of vanes 21b in the circumferential direction so as to slide on the inner peripheral surface of the housing 22 via the seal member 21s. The vane 21b may be formed as a separate member and joined to the shaft portion 21a of the rotor 21. Further, a support portion 22e extending in the direction of the rotation center of the rotor 21 is formed in the housing 22, and is arranged so as to be in sliding contact with the outer peripheral surface of the shaft portion 21a of the rotor 21 via a seal member 22s. . Thus, pressure chambers C1a, C2a, C1b, and C2b are formed in the circumferential direction in the housing 22.

  As shown in FIG. 3, the vane 21b is arrange | positioned so that it may extend in the circumferential direction 180 degree | times centering on the axial part 21a. On the other hand, the support portion 22e is disposed on the inner peripheral surface of the housing 22 so as to extend from both sides of the circumferential direction 180 ° toward the shaft portion 21a. Since it is such a form, a pair of pressure chambers C1a and C1b and a pair of pressure chambers C2a and C2b are formed on opposite sides of the shaft portion 21a by 180 °. The shaft 21a of the rotor 21 has communication holes P1c and P2c. The pressure chamber C1a and the pressure chamber C1b communicate with each other via the communication hole P1c, and the pressure chamber C2a and the pressure chamber C2b communicate with each other. They communicate with each other via P2c. As a result, pressure chambers having the same pressure are formed on the opposite side of 180 ° around the shaft portion 21a, and the rotor 21 is not pressed against one side in the circumferential direction of the housing 22 even during pressure control. Good relative rotation between 21 and housing 22 can be maintained. The housing 22 is joined to the vehicle body (indicated by hatching in FIG. 3).

  As shown in FIG. 2, the housing 22 includes three cylindrical members 22a, 22b, and 22c. One end of the cylindrical member 22a has a shaft portion 21a of the rotor 21 via a bearing 22j and a seal member 22r. Is arranged to be supported rotatably. Furthermore, the cylindrical member 22b is disposed so as to sandwich the vane 21b of the rotor 21 together with the cylindrical member 22a, and the other side of the shaft portion 21a of the rotor 21 is rotatable via a bearing 22j and a seal member 22r. It is supported by. And when the cylindrical member 22c is arrange | positioned so that the vane 21b of the rotor 21 may be enclosed between the cylindrical member 22a and the cylindrical member 22b, and it welds along the connection part of the circumferential direction, it will show in FIG. Thus, the pressure chambers C1a, C2a, C1b, and C2b are formed in the circumferential direction in the housing 22.

  Further, as shown in FIG. 2, the shaft portion 21a of the rotor 21 is splined to the torsion bar F11 via the cylindrical fastening member F11c and splined to the torsion bar F12 via the fastening member F12c. Yes. Thus, the torsion bar F11 and the torsion bar F12 constituting the stabilizer bar of the front wheel side stabilizer device F10 are in a state of being able to rotate integrally via the shaft portion 21a of the rotor 21. The fastening members F11c and F12c may be configured by a universal joint (not shown).

  Further, as shown in FIG. 3, the rotary valve F20 is formed with communication holes FPa and FPb that open to the pressure chambers C1a and C2a. These communication holes FPa and FPb pass through the communication passages 30a and 30b, respectively. Via the communication holes RPa and RPb of the rotary valve R20. That is, the communication passage 30a that connects the pressure chamber C1a of the rotary valve F20 and the pressure chamber C1a of the rotary valve R20, and the communication passage 30b that connects the pressure chamber C2a of the rotary valve F20 and the pressure chamber C2a of the rotary valve R20, both. When the front wheel side stabilizer bars (F11, F12) and the rear wheel side stabilizer bars (R11, R12) are driven in the same direction with respect to the vehicle (for example, when the vehicle moves up and down parallel to the road surface) The pressure chambers on the side where the increase is connected are connected to each other.

  At least one of the communication passage 30a that communicates the pressure chamber C1a of the rotary valve F20 and the pressure chamber C1a of the rotary valve R20, and the communication passage 30b that communicates the pressure chamber C2a of the rotary valve F20 and the pressure chamber C2a of the rotary valve R20 ( In this embodiment, an electromagnetic on-off valve 41 is interposed in the communication passage 30b) as a first on-off valve. In addition, an electromagnetic opening / closing valve 42 is interposed as a second opening / closing valve in the connecting passage 30e that connects the communication passages 30a and 30b. Further, as shown in FIGS. 1 and 2, the communication paths 30a and 30b are connected to the accumulator 50 through the communication paths 30c and 30d, respectively. And in the communication passages 30c and 30d, electromagnetic on-off valves 43 and 44 are interposed as third and fourth on-off valves. In FIG. 3, these accumulators 50 are omitted.

  In this embodiment, as shown in FIG. 2, the sealing plugs 51 and 52 are interposed in the housing 22 of the rotary valve F20, through which the pressure chambers C1a, C2a, C1b and C2b, and thus the communication passages 30a to 30a. System oil is sealed in the accumulator 50 through 30d as a pressurized fluid pressurized to a predetermined pressure. It should be noted that the sealing plugs 51 and 52 are not limited to the positions shown in FIG. 2, and may be interposed in any part of the communication passages 30a to 30d. Retained.

  Thus, even if the system oil in the communication passage 30 and the pressure chambers C1a, C2a, C1b, and C2b is thermally expanded, the pressure fluctuation caused thereby is absorbed by the accumulator 50. Is possible. Further, air may be mixed when the system oil is sealed from the sealing plugs 51 and 52, and the oil pressure may fluctuate due to air bubbles. However, when the electromagnetic on-off valves 43 and 44 are in the open position, the accumulator is connected to them. The system oil introduced into 50 is set to a predetermined pressure. For example, even if the air bubbles are crushed after the system oil is filled and the pressure in the communication passage 30 is reduced, the communication passages 30c and 30d communicate with the accumulator 50 if the electromagnetic on-off valves 43 and 44 are in the open position. The hydraulic pressures in the pressure chambers C1a, C2a, C1b, and C2b of the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 are maintained at a predetermined pressure.

  Further, the communication passages 30a to 30d and the connection passage 30e can be constituted by flexible tubes and can be easily piped, so that the electromagnetic on-off valves 41 to 44 and the like can be arranged at appropriate positions and remotely controlled. Accordingly, the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 have a high degree of freedom when mounted on the vehicle, and can be easily mounted.

  The electromagnetic on-off valves 41 to 44 are controlled to be opened and closed by a stabilizer electronic control unit ECU in the electronic control unit 100 shown in FIG. A manual switch MS is connected to the stabilizer electronic control unit ECU, and the vehicle attitude control operation can be turned on and off by a driver's switch operation. Further, in the electronic control device 100, a detection signal such as a steering angle of a steering wheel (not shown), a vehicle speed, that is, a vehicle speed, is input to the lateral acceleration estimation unit YG, for example, based on the steering angle and the vehicle speed. The lateral acceleration (Gy) is estimated and calculated, and the electromagnetic on-off valves 41 to 44 are controlled to open and close according to the lateral acceleration (Gy) and the like. Hereinafter, the operation of the attitude control device of the present embodiment will be described according to the traveling state of the vehicle.

  First, when the vehicle (not shown) is traveling straight, the electromagnetic on-off valve 41 serving as the first on-off valve is set to the open position. At this time, the electromagnetic on-off valves 42 to 44 as the second to fourth on-off valves may be in the open position or the closed position, but for example, when both are in the closed position, the following braking state is obtained. As a result, the communication passage 30b is opened, and the pressure chamber C1a of the rotary valve F20 and the pressure chamber C1a of the rotary valve R20 communicate with each other through the communication passage 30a, and the pressure chamber C2b of the rotary valve F20 through the communication passage 30b. And the pressure chamber C2b of the rotary valve R20 communicate with each other, but when the vehicle is traveling straight and moves up and down substantially parallel to the road surface, the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 are Since the operation is similar, fluid movement in the communication passages 30a and 30b does not occur.

  Next, when the electronic control unit 100 determines that the vehicle is in a braking state based on a brake switch (not shown) or the like, the electromagnetic on-off valve 41 as the first on-off valve is set to the open position, and the second to fourth The electromagnetic on / off valves 42 to 44 as the on / off valves are closed. As a result, the communication passage 30b is opened as described above, and the pressure chamber C1a of the rotary valve F20 and the pressure chamber C1a of the rotary valve R20 communicate with each other via the communication passage 30a, and the rotary valve F20 via the communication passage 30b. The pressure chamber C2b and the pressure chamber C2b of the rotary valve R20 communicate with each other. Accordingly, the braking force applied to the vehicle applies a force that rotates counterclockwise in FIG. 1 to the rotary valve F20 (rotor 21) in the front wheel side stabilizer device F10, whereas in the rear wheel side stabilizer device R10, the rotary valve R20. A force that rotates clockwise in FIG. 1 is applied to (the rotor 21).

  As a result, in FIG. 2, the fluid discharged from the pressure chamber C2a of the rotary valve F20 and the fluid discharged from the pressure chamber C2a of the rotary valve R20 (applying a reverse force) collide in the communication path 30b. However, since the pressure of the fluid discharged from the rotary valve F20 of the front wheel side stabilizer device F10 is larger, the rotary valve R20 (the rotor 21) of the rear wheel side stabilizer device R10 is driven to rotate counterclockwise. . Thereby, the rear part of the vehicle is pulled down, and so-called nose diving is suppressed. That is, the pitching motion of the vehicle is suppressed.

  Further, when the vehicle starts, the state is the reverse of the above, and the lift (scort) of the front portion of the vehicle is suppressed, and the pitching motion of the vehicle is suppressed. When the occupant is seated in the rear seat (not shown) of the vehicle or when the rear load room (not shown) is loaded and the rear load increases, The lift of the is suppressed.

  When the electronic control device 100 determines that the vehicle is in a turning state based on the lateral acceleration (Gy) of the vehicle estimated and calculated based on the steering angle and the vehicle speed as described above, the first to fourth All of the electromagnetic on-off valves 41 to 44 as on-off valves are switched to the closed position. As a result, both the rotary valve F20 and the rotary valve R20 are locked, and the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 are both twisted by the torsion bar on one side with respect to the vehicle center. The rigidity is increased and the rolling motion of the vehicle is suppressed.

  Further, when the electronic control unit 100 determines that the vehicle is traveling on a rough road based on, for example, a change in vehicle height detected by a vehicle height sensor (not shown), the first to fourth on-off valves All the electromagnetic on-off valves 41 to 44 are switched to the open position. As a result, the connection state between the front wheel side stabilizer device F10 and the rear wheel side stabilizer device R10 is released, and both the rotary valve F20 and the rotary valve R20 are in a free state (a state in which each rotor 21 can freely rotate). Thus, since each wheel functions as a normal stabilizer bar, it is possible to avoid the influence of other wheels when traveling on a rough road as before.

It is a perspective view showing arrangement of main components of a posture control device of a vehicle concerning one embodiment of the present invention. 1 is a cross-sectional view showing a partial structure of a vehicle attitude control device according to an embodiment of the present invention. 1 is a longitudinal sectional view showing a partial structure of a vehicle attitude control device according to an embodiment of the present invention.

Explanation of symbols

F10 Front wheel side stabilizer device R10 Rear wheel side stabilizer device F11c, F12c Fastening member F20, R20 Rotary valve (intermittent means)
21 Rotor 21b Vane 22 Housings 22a, 22b, 22c Tubular members C1a, C1b, C2a, C2b Pressure chambers FPa, FPb, RPa, RPb Communication holes 30a, 30b, 30c, 30d Communication path 30e Connection path 40 Switching means 41 Electromagnetic switching Valve (first on-off valve)
42 Electromagnetic on-off valve (second on-off valve)
43 Electromagnetic on-off valve (third on-off valve)
44 Electromagnetic on-off valve (fourth on-off valve)
50 Accumulator 51, 52 Sealing plug 100 Electronic control unit

Claims (6)

  A front wheel side stabilizer device connected between the front wheels of the vehicle, a rear wheel side stabilizer device connected between the rear wheels of the vehicle, and an intermediate portion of the front wheel side stabilizer bar constituting the front wheel side stabilizer device. A first rotating member that rotates integrally with the front wheel side stabilizer bar, and at least two pressure chambers in the circumferential direction between the first rotating member and the first rotating member that are rotatably accommodated. A front wheel side intermittent means having a first housing formed and supported by a vehicle body in front of the vehicle, in which two pressure chambers of the first housing are filled, and the rear wheel side stabilizer device are configured. A second rotating member interposed in an intermediate portion of the rear wheel side stabilizer bar and rotating integrally with the rear wheel side stabilizer bar; and the second rotating member that rotatably accommodates the second rotating member. And a second housing that forms at least two pressure chambers in the circumferential direction and supports the vehicle body at the rear of the vehicle, and the two pressure chambers of the second housing are filled with fluid. Of the two pressure chambers of each of the intermittent means and the rear wheel side intermittent means and the front wheel side intermittent means, the rear wheel side stabilizer bar and the front wheel side stabilizer bar are driven in the same direction with respect to the vehicle. A pair of communication passages that connect pressure chambers on the side where the pressure increases, a connection passage that connects the pair of communication passages, and at least one of the pair of communication passages. A vehicle attitude control device comprising: a first on-off valve that opens and closes; a second on-off valve that opens and closes the connecting path; and a switching means that switches between the first and second on-off valves.   The switching means is connected to the pair of communication paths, and stores an accumulator that contains a part of the fluid sealed in the pair of communication paths, and is interposed between the accumulator and the pair of communication paths. A third and a fourth on-off valve for opening and closing the communication passage; and opening and closing the third and fourth on-off valves, respectively, in the two pressure chambers of each of the front wheel side intermittent means and the rear wheel side intermittent means. 2. The vehicle attitude control device according to claim 1, wherein the fluid pressure is maintained at a predetermined pressure.   3. The vehicle attitude control device according to claim 2, wherein the switching means controls opening and closing of the first to fourth on-off valves in accordance with at least a running state of the vehicle.   4. The vehicle attitude control device according to claim 3, wherein the switching means switches all of the first to fourth on-off valves to a closed position when the vehicle is in a turning state.   4. The vehicle attitude control device according to claim 3, wherein the switching means switches all the first to fourth on-off valves to an open position when the vehicle is in a rough road running state.   The switching means sets the first on-off valve to an open position and sets the second to fourth on-off valves to a closed position when the vehicle is in a braking state and a starting state. 4. A posture control apparatus for a vehicle according to 3.

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