JPS606804B2 - Vehicle attitude control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a gas spring device for vehicle suspension to prevent the vehicle body from tilting in its running position due to sudden changes in wheel motion caused by the operation of brakes, steering devices, etc. This invention relates to a posture control device for a chariot ball to be corrected.

In general, gas spring devices have a spring constant of bran A-N- shown in Figure 2.
As shown in E, it has the property of constantly increasing as the load increases, so when used as a suspension spring for a wheel, it has the advantage of being able to support a high load without impairing riding comfort.

On the other hand, in a low load region, the spring constant is extremely reduced and the vertical displacement of the vehicle body in response to a change in load becomes large, which has the disadvantage of promoting pitching and rolling of the vehicle body. Therefore, the spring characteristics required for a wheel suspension spring are as shown by the line A'-N-B in Fig. It is necessary to increase the constant. In addition, a wheel equipped with a gas spring device for vehicle suspension, in which the spring constant of the gas spring device is increased and changed in a timely manner to stabilize the running posture of the vehicle body, is disclosed in, for example, Japanese Patent Laid-Open No. 50-146.
As shown in Japanese Patent Application No. 022, the spring constant is increased only when the wheel is braked, regardless of the magnitude of the load acting on the gas spring device, and the spring constant is increased only when the wheel is braked. It is not something that satisfies the characteristics.

The present invention automatically corrects the sudden change in the motion of the vehicle due to the operation of the wheel brakes, steering device, etc. by controlling the gas spring device for suspension of the vehicle. In addition, even after the modification, the gas '
It is an object of the present invention to provide a wheel attitude control device in which a springing device operates so as to satisfy the above-mentioned required spring characteristics.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.A known hydraulic shock absorber D is interposed between the front, rear, left, and right wheels W (only one of which is shown in the figure) of the vehicle and the vehicle body F. One pupil body 1 is prepared for each of the shock absorbers D, and they are fixed at appropriate positions on the vehicle body F.

The inside of the cliff body 1 is divided into three chambers, an upper oil chamber 4, an air chamber 5, and a lower oil chamber 6, by two upper and lower movable diaphragms 2 and 3, and the air chamber 5 is filled with spring gas 7. For example, high-pressure nitrogen gas is filled in, and the lower oil chamber 6 is connected to the hydraulic chamber of the corresponding shock absorber ○ via a lotus pipe 8 in order to apply the load of the vehicle body as hydraulic pressure. The center part of a first elastic resistor 9 made of rubber or the like that can be curved toward the oil chamber 5 and can fit into the concave surface thereof is fixed with a caulking pin 11, and the convex surface of the diaphragm 3 is attached to the inner wall of the lower oil chamber 6. The outer periphery of an annular second elastic resistor 10 made of rubber or the like which can be adapted to the above is tied.

The upper oil chamber 4 includes a diaphragm position pupil detection valve 12 that is linked to the lower diaphragm 3 and a brake operation detection valve 13 that is linked to the brake device.
A hydraulic pump 15 and an oil reservoir 16 are connected as shown in the figure through a steering operation detection valve 14 that is linked to the steering device, and the three valves 12, 13, 1 are connected as shown below.
The configuration of No. 4 will be explained.

A valve box 17 of the diaphragm position detection valve 12 is fixed to the lower surface of the sparrow body 1, and a cylindrical valve chamber 18 inside the valve box 17 has a boat 20 connected to a flow path 19 extending from the hydraulic pump 15, and another The boats 21 connected to the flow path 22 open □, and the spool valve 23 for opening and closing the boats 20, 21 is accommodated in the valve chamber 18, and is connected to the lower diaphragm 3 via a pair of upper and lower buffer springs 24, 24'. It is connected to a detection rod 25 that protrudes downward from the movable center. Thus, the spool valve 23 is connected to the lower diaphragm 3.
The boat 20, 21 is cut off when the bar is within a range from a predetermined neutral position to the lowering limit, and the boat 20, 21 is closed when the bar is in a range other than that. A valve box 26 of the brake operation detection valve 13 is fixed at a suitable location on the vehicle body F, and a cylindrical valve chamber 27 inside the valve box 26 has a boat 28 connected to the flow path 22 and a flow valve whose end opens to the oil sump 16. A boat 29 connected to the passage 32 and boats 30 and 31 connected to another common passage 33 are closed, and a spool valve 3 capable of left and right tank movement opens and closes the boats 28 to 31.
4 and a return imitation 35 for pushing it to the right are housed in the valve chamber 27.

A pressure receiving chamber 36 facing the right end of the spool valve 34 is defined in the valve chamber 27, and a pressure receiving chamber 36 is selected between the pressure receiving chamber 36 and the hydraulic circuit L of the brake device. When the spool valve 34 is held in the right position by the elastic force of the return valve 35, it closes the gap between the boats 29 and 31 and cuts off the gap between the boats 28 and 30, so that the pressure receiving chamber 3
When pushed to the left position by the brake hydraulic pressure introduced at 6, the above-mentioned operating and blocking states are respectively switched in reverse. Steering operation detection valve 14
A valve box 37 is fixed to the vehicle body F in the vicinity of the rack punch R of the steering device, and a shilling-shaped valve chamber 38 in the valve box 37 has a branch path 22' from the flow path 22 and a branch path 22' from the flow path 33. Boats 39, 40 are connected to each other, and boats 41, 4 are connected to the upper oil chambers 4 of all the cliff bodies 1 prepared for each buffer D via channels 43, 43, . . .
2 is closed, and a spool valve 44 that can be slid up and down to open and close them, and a return valve 45 that springs it downward are housed in the valve chamber 38, and the lower end of this spool valve 44 is placed at a suitable position on the outer periphery of the rack punch R. It protrudes outside the valve chamber 38 so as to engage with the formed cam recess C.

Therefore, when the rack punch R is in the neutral position (when traveling straight), the spool valve 44 engages with the cam recess C and descends to pass between the boats 40 and 42 while also blocking the gap between the boats 39 and 41. , when the rack punch R is displaced to the left or right (
When the cam is rotated), it is pushed out from the cam recess C and rises to switch between the open and closed states. Next, the function of this embodiment will be explained.Firstly, it is a buffer function.When the shock absorber ○ receives a dynamic load from the vehicle body F or wheels W, it expands and contracts, and the hydraulic pressure in the lower oil chamber 6 corresponding to it increases and decreases. For example, the spring gas 7 contracts or expands to balance its pressure with the oil pressure, and the lower diaphragm 3 vibrates up and down accordingly.

By the way, in the high-load region above point N in FIG. 2, the lower cornea 3 is in a neutral state where the first and second elastic resistors 9, 10 are simply engaged with the diaphragm 3 in between, as shown in FIG. It moves up and down from the position to the raised position where both the resistors 9 and 10 are vertically separated, and during this time it does not receive any resistance from the resistors 9 and 10, so its spring characteristics are the same as those of the conventional device. The curve NA in FIG. The pressure is applied to provide resistance to the expansion of the spring gas 7 underlying the diaphragm 3, and the resistance increases as the expansion of the spring gas 7 progresses.

As a result, as shown by the curve N-A' in FIG. 2, the expansion of the spring gas 7 as the load decreases is significantly less than in the conventional device, and the spring constant therefore increases as the load decreases. It turns out. When the lower diaphragm 3 vibrates as described above, the detection member 25 also vibrates at the same time, but the buffer springs 24, 2
4' absorbs the vibration, so that the spool valve 23 of the diaphragm position detection valve 12 can remain in the position before the vibration.

Next, to explain the attitude control action, the brake device is in a non-operating state and no oil pressure is generated in its hydraulic circuit L', and the steering device is in a straight-Z state and the rack punch R is in the neutral position. When the brake operation detection valve 13 and the steering operation detection valve 14 are both maintained in the illustrated state, the spool valve 34 allows transportation between the boats 29 and 31 and cuts off the connection between the boats 28 and 30, and the spool valve 44 by boat 40,42
Since the space between the boats 39 and 41 is closed, the upper oil chamber 4 of the cover 1 is opened to the oil sump 16 via the channels 43, 33, and 32, and the oil in the upper oil chamber 4 flows into the oil sump. At the same time, the upper diaphragm 2 is pushed toward the ceiling surface of the shade 1 by the pressure of the spring gas 7.

Therefore, the brake system is now activated and its hydraulic circuit L
When brake hydraulic pressure is introduced into the pressure receiving chamber 36, the spool valve 34 is pushed to the left position by the hydraulic pressure, and the connection between the boats 29 and 31 is cut off from Ren communication, and the connection between the boats 28 and 30 is changed from blocking to Ren communication. Switch to each.

The front wheel load increases due to the braking action of the vehicle, and the vehicle body
When the front wheel tilts downward, the shock absorber D on the front wheel side contracts and transfers pressure oil from its hydraulic chamber to the lower oil chamber 6 of the corresponding weight body 1, causing the lower diaphragm 3 to rise. Then, the spool valve 23 of the diaphragm position detection valve 12 is moved upward by the detection lever 25, and the connection between the boats 20 and 21 is made clear. For this reason, hydraulic pump 1
Pressure oil discharged from 5 is connected to the upper oil chamber 4 through channels 19, 22, 33, and 43, and the oil pressure lowers the lower corner membrane 3 via the upper diaphragm 2 and the spring gas 7, and lowers the lower corner membrane 3. When the diaphragm 3 returns to its original neutral position, the diaphragm position detection valve 12
The spool valve 23 is also returned to the neutral position by the detection lever 25, cutting off the connection between the boats 20 and 21, and stopping oil supply to the upper oil chamber 4. By the way, according to the above-mentioned lowering of the lower diaphragm 3, the amount of oil discharged from the lower oil chamber 6 to the shock absorber D on the front wheel side when it contracts is returned, so the shock absorber D is expanded to its original state. Correct the front downward slope of the vehicle body F to a horizontal state.

Next, when the steering device is operated to turn from the illustrated state, the rack village R is displaced to the right or left to push the spool valve 44 of the steering operation detection valve 14 out of the cam recess C, that is, to raise the boat 40, 42 will be switched from traffic to disconnection, and between boats 39 and 41 will be switched from disconnection to Ren traffic.

When the car body F is tilted so that its outer wheel side is lowered by the action of the centrifugal force generated in response to the turning of the car case, the shock absorber D on the outer wheel side contracts and the oil pressure chamber moves from the hydraulic chamber to the lower oil chamber of the corresponding cover body 1. 6, and the lower diaphragm 3 is raised. Then, the detection rod 25 detects the spool valve 2 of the diaphragm position detection valve 12.
3 is moved up and the distance between boats 20 and 21 is passed. Therefore, oil flows from the hydraulic pump 15 to the flow paths 19, 22, 22'.
, 43 to the upper oil chamber 4 of the crab body 1, and the oil pressure is supplied to the lower diaphragm 3 via the upper diaphragm 2 and the spring gas 7.
When the L lower diaphragm 3 returns to the original neutral position, the spool valve 23 of the diaphragm position detection valve 12 is also returned to the neutral position by the detection rod 25, cutting off the boat 20'' 21 and allowing the upper oil chamber 4 to flow. By the way, according to the above-mentioned lowering of the lower diaphragm 3, the amount of oil discharged from the lower oil chamber 6 to the shock absorber D on the outer ring side when it contracts is returned, so the shock absorber D
extends to its original state and corrects the lateral inclination of the vehicle body F to a horizontal state.

What is particularly noteworthy in this case is that after the inclination of the vehicle body F is corrected, the lower diaphragm 3 is maintained at its original neutral position, so that no load is applied to the shock absorber D in this corrected state. In some cases, a similar damping effect as described above occurs, and desirable spring characteristics such as curved bar NB in FIG. 2 can be exhibited.

In the above-mentioned embodiment, the motion control detection valve opens when detecting the operation of a device that controls wheel motion, and the brake zero operation detection valve opens when detecting the operation of a brake device and a steering device, respectively. Although the valve 13 and the steering operation detection valve 14 are specifically shown, it is conceivable to use an accelerator operation detection valve that opens upon detecting, for example, sudden acceleration or sudden reduction of the accelerator. In other words, ``Generally, when the wheels suddenly accelerate or decelerate, the running posture of the vehicle body tends to lean, but if the above-mentioned accelerator operation detection valve is used as the motion control detection valve of the present invention, the vehicle body tilts even when the vehicle suddenly accelerates or suddenly decelerates. As described above, according to the present invention, it is possible to accurately correct the running posture of the car body due to changes in motion such as braking and turning of the car, and moreover, the correction To obtain the desired spring characteristics, which remain the same after modification as before the modification, by increasing the spring constant in the low load region as the load decreases without any loss of the original spring characteristics of the gas spring in the high load region. Therefore, rolling and pitching of the vehicle body can be suppressed without impairing ride comfort, and handling stability can be improved in conjunction with correction of the vehicle running attitude.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the device of the present invention, and FIG. 2 is a spring characteristic diagram thereof. D...Buffer, F...Car body, W...Wheel, 1... Weight body, 2... Upper diaphragm, 3... Lower diaphragm, 4... ...Upper oil chamber, 5... Air chamber 6...Lower oil chamber, 7...Air spring 9, 10
...First and second elastic resistors, 12... Diaphragm position detection valve, 13, 14... Brake operation detection valve and steering operation detection valve as motion control detection valves, 15
...Hydraulic pump as a hydraulic source. Figure 1 Figure 2

Claims (1)

[Claims] 1 The interior of the casing is divided into an air chamber for sealing spring gas by upper and lower diaphragms facing each other, and upper and lower oil chambers adjacent to the upper and lower sides of the air chamber, respectively, and the lower oil chamber is located between the vehicle body and the wheels. An elastic resistor is provided opposite to the lower diaphragm, communicating with a hydraulic chamber of a hydraulic shock absorber installed in the lower diaphragm, and providing elastic resistance to the lower diaphragm being lowered from a predetermined neutral position; A diaphragm position detection valve that detects and opens when the diaphragm is above the neutral position, and a motion control detection valve that opens when it detects the operation of a device that controls the motion of the vehicle are connected in series. An attitude control device for a vehicle, which connects the upper oil chamber to a hydraulic power source via a hydraulic power source.