JPH11123920A - Height adjusting device for air-suspension vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To return the height of a vehicle to a definite proper height at all times, in a height adjusting device for an air-suspension vehicle, by making the height return amount at the time of return of vehicle height to a given proper amount independently of the length of elapsed time in the condition of lowered height, so that the excessively height can be prevented. SOLUTION: In this height adjusting device, exhaust valves 11, 17 are interposed in the air circuits (for instance, air circuits 8, 15 between leveling valves 1A, 1B and an auxiliary air tank 9) leading from an air supply source 6 to the auxiliary air tank 9; and mechanical cut valves 26A, 26B as air-supply cutoff valves for closing and intercepting the air supply to the inside of the auxiliary air tank 9 when it is changed over to a discharging condition in which air springs 12, 18 are opened to the atmosphere and also both the air springs 12, 18 and the auxiliary air tank 9 are cut off are interposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting a vehicle height using an air suspension in a vehicle having an air suspension, and more particularly to a technique for optimizing a vehicle height when returning.

[0002]

2. Description of the Related Art In recent years, in the case of vehicles such as large buses which frequently run at high speed, air suspension vehicles using an air spring as a suspension device of the vehicle body are becoming mainstream.
Such an air suspension vehicle uses air (air), which is a compressible fluid, for the air spring, so that it has better ride comfort and a leveling valve as compared with a normal one using a leaf spring or the like. Is advantageous in that a constant vehicle height can be maintained regardless of the loaded state.

As shown in FIG. 3, the leveling valve 1 is interposed between an air spring 2 and an air supply source for supplying air to the air spring 2, and its valve body 1a is used as a sprung system. And a lever 1b for driving the leveling valve 1 is fixed via a connecting rod 4 to an axle 5 (for example, a front axle; I-beam) as a unsprung system.

The leveling valve 1 supplies air to the air spring 2 or discharges air from the air spring 2 in accordance with the distance between the lower surface of the body frame 3 and each axle 5, thereby reducing the vehicle height. Keep constant. By the way, various techniques for discharging air from the air spring 2 at the time of occupant getting on and off a bus or the like so as to lower the vehicle height and improve the getting on and off property are known (Japanese Patent Application Laid-Open No. 9-58245, Japanese Utility Model Application Laid-Open No. Hei 5-58245). -76810, JP-A-5-238237 and JP-A-5-76809.

FIG. 4 shows an example of a configuration of a vehicle height adjusting device in such an air suspension vehicle. This figure shows an air circuit for left and right air springs on the front side of the vehicle. The air circuit 7 connected to the air supply source 6 is branched into two, and one of the branched air circuits 8 is communicated with one of the partitioned chambers A of the auxiliary air tank 9 via the left leveling valve 1A. The air circuit 10 connected to the chamber A is connected to a left air spring 12 via a left exhaust valve 11.

A leveling valve 1 is provided between the upstream side of the leveling valve 1A of the air circuit 8 and the downstream side of the leveling valve 1A and upstream of the auxiliary air tank 9.
A bypass air circuit 13 for bypassing A is connected, and the bypass air circuit 13 is provided with an electromagnetic valve 14 for supplying bypass air. On the other hand, the other branched air circuit 15 is communicated with the other chamber B of the auxiliary air tank 9 via the right leveling valve 1B. The air circuit 16 communicated with the chamber B is communicated with a right air spring 18 via a right exhaust valve 17.

The leveling valve 1B of the air circuit 15
A bypass air circuit 19 that bypasses the leveling valve 1B is connected between the upstream side and the downstream side of the leveling valve 1B and the upstream side of the auxiliary air tank 9.
An electromagnetic valve 20 for supplying bypass air is interposed in the bypass air circuit 19. The left exhaust valve 11 and the right exhaust valve 17 are each operated by a signal pressure from an electromagnetic valve 21 for signal pressure control.
Signal pressure circuits 22 from the electromagnetic valves 21 are respectively connected. The signal pressure control electromagnetic valve 21 is connected to the air circuit 7.
The air circuit 23 is connected to the air circuit 23 connected to the branch circuit upstream of the air circuits 8 and 15.

[0008] The auxiliary air tank 9 secures an air capacity for the auxiliary air spring when the size and number of the air springs are limited by the vehicle layout. Here, the electromagnetic valve 21 for signal pressure control
Is to connect the exhaust valves 11 and 17 to the air spring 1.
A, 1B is selectively switched between a ventilation state for communicating the auxiliary air tank 9 with the auxiliary air tank 9 and an exhaust state for opening the air springs 1A, 1B to the atmosphere and shutting off the air springs 1A, 1B and the auxiliary air tank 9. , Is controlled by a signal from the changeover switch 24.

That is, the electromagnetic valve 21 is provided with the changeover switch 2
By switching 4 to the UP side,
By switching to the DOWN side,
Can be switched. The bypass air supply electromagnetic valves 14 and 20 can be selectively switched between a ventilation state for opening the bypass air circuits 13 and 19 and a cutoff state for shutting off the bypass air circuits 13 and 19. Switching is controlled by a signal.

That is, the electromagnetic valves 14 and 20 are switched to the ventilation state by switching the changeover switch 24 to the UP side, and to the shutoff state by switching to the DOWN side. Note that a timer circuit 25 is provided in a signal circuit from the changeover switch 24 to the electromagnetic valves 14 and 20. This timer circuit 25 will be described later.

The operation of the above configuration will be described with reference to FIGS. First, the normal operation of the vehicle will be described.
The electromagnetic valves 14 and 20 for supplying bypass air are shut off, the electromagnetic valve 21 for signal pressure control is shut off, and the exhaust valves 11 and 17 are vented. In this state,
When the vehicle is stationary (stopped), the leveling valves 1A, 1
The lever 1b of B is in a horizontal state, the air is shut off by the leveling valves 1A, 1B, and the air springs 12, 1
8 is not supplied. That is, the state is maintained.

On the other hand, when the vehicle bounces, the air springs 12, 18 are crushed and the leveling valves 1A, 1
The lever 1b of B moves upward as shown in FIG. Therefore, the air from the air supply source 6 is supplied to the leveling valve 1.
The air springs 12 and 18 are supplied from the air springs A and 1B to extend (return) the crushed air springs 12 and 18.

When the vehicle rebounds, the air springs 12, 18 are extended and the leveling valves 1A, 1
The lever 1b of B moves downward as shown by b in FIG. Therefore, the air from the air supply source 6 is supplied to the leveling valve 1.
A, 1B, while the air springs 1A, 1
The air on the B side is exhausted from exhaust ports provided in the leveling valves 1A and 1B, and contracts (returns) the extended air springs 12 and 18.

Next, the operation when the vehicle height is lowered will be described. By operating the changeover switch 24 in the driver's seat, the electromagnetic valve 21 for signal pressure control is switched from the shut-off state to the ventilation state. The signal pressure supplied from the electromagnetic valve 21 for controlling the signal pressure is supplied to the signal ports of the exhaust valves 11 and 17.

The exhaust valves 11 and 17 normally supply air from the leveling valves 1A and 1B (the auxiliary air tank 9 side) to the air springs 12 and 18; however, the electromagnetic valve 21 for signal pressure control is used. Is supplied to the signal ports of the exhaust valves 11 and 17, the ports on the leveling valves 1 A and 1 B side are shut off, and the air springs 12 and 18 and the exhaust port 1 are closed.
The air in the air springs 12 and 18 is discharged to the atmosphere.

When the air is discharged, the air springs 12 and 18 are crushed by the vehicle weight and the vehicle height is lowered. In this state, the leveling valves 1A, 1
Since B is in a bound state, air is supplied to the auxiliary air tank 9 side, and is supplied until the vehicle pressure reaches a specified pressure depending on the time during which the vehicle height is lowered.

Next, a description will be given of when the vehicle is returned to the height. By operating the changeover switch 24 in the driver's seat portion, the electromagnetic valve 21 for signal pressure control switches from the ventilation state to the cutoff state. The air supplied to the signal ports of the exhaust valves 11 and 17 is exhausted from the electromagnetic valve 21 for signal pressure control, and the exhaust valves 11 and 17 return to the normal state (the leveling valves 1A and 1B and the air spring 12). , 18 are in communication).

By operating the changeover switch 24, the bypass air supply electromagnetic valves 14, 20 are simultaneously switched from the shut-off state to the ventilation state. That is, since the opening amounts of the leveling valves 1A and 1B vary depending on the state of the vehicle height, the bypass air supply electromagnetic valve switches to the ventilation state in order to return the vehicle height in a short time. The air from the air supply source 6 is supplied to the air springs 12 and 18 from both the bypass air supply electromagnetic valves 14 and 21 and the leveling valves 1A and 1B.

Electromagnetic valves 14 and 20 for supplying bypass air
Automatically switches from the ventilation state to the cut-off state according to the set time by the timer circuit 25 set in advance to the time when the vehicle height returns to the normal position.

[0020]

Here, when the vehicle height is lowered for a long time during the vehicle height reduction described above, as described above, the air is supplied to the auxiliary air tank 9 side until the vehicle reaches the vehicle specified pressure. As a result, the pressure in the auxiliary air tank 9 rises more than necessary. For this reason, at the time of returning to the vehicle height, the auxiliary air tank 9 in which the internal pressure has increased more than necessary temporarily supplies more air than necessary to the air springs 12 and 18, so that the vehicle height becomes too high and the vehicle height becomes too high. Cannot be returned to an appropriate height.

In view of the above-mentioned conventional problems, the present invention sets the vehicle height return amount at the time of vehicle height return to a constant appropriate amount regardless of the length of time elapsed when the vehicle height is lowered. hand,
It is an object of the present invention to prevent a vehicle height from rising too high and to allow the vehicle height to always return to a constant appropriate height.

[0022]

According to a first aspect of the present invention, there is provided an air pump which is interposed between a sprung system of a vehicle and front, rear, left and right unsprung systems to support the sprung system. A leveling valve interposed in an air circuit between the air spring and an air supply source for supplying air to the air spring. When the vehicle deviates from the point, air is supplied to and discharged from the air spring to adjust the vehicle height to a predetermined height, while an auxiliary air tank interposed in an air circuit between the leveling valve and the air spring is provided. An exhaust valve interposed in an air circuit between the auxiliary air tank and the air spring, the air valve communicating with the air spring and the auxiliary air tank; An exhaust valve that can be selectively switched between an air release state and an air exhaust state that shuts off an air spring and an auxiliary air tank; and an air circuit between an upstream side of the leveling valve and a downstream side of the leveling valve and upstream of the auxiliary air tank. A bypass air circuit that is connected to bypass the leveling valve, and is interposed in the bypass air circuit;
A vehicle height adjustment device for an air suspension vehicle, comprising: a bypass air supply opening / closing valve selectively switched between a ventilation state for opening the bypass air circuit and a shutoff state for shutting off the air supply circuit. When the exhaust valve is switched to an exhaust state in which the air spring is opened to the atmosphere and the air spring and the auxiliary air tank are shut off, the air supply from the air circuit to the air tank is closed to shut off the air supply to the auxiliary air tank. An open / close valve for shutting off air supply is interposed.

According to a second aspect of the present invention, the opening / closing valve for shutting off the air supply has a signal port to which a signal pressure from a signal pressure control valve connected to an air supply source is supplied, and based on the signal pressure. And a mechanical cut valve which is opened and opened. The invention according to claim 3 is characterized in that the air supply cutoff opening / closing valve is an electromagnetic valve that is opened based on an electric signal.

The invention according to a fourth aspect is characterized in that the air supply shutoff valve is interposed in an air circuit between the leveling valve and an auxiliary air tank. The invention according to claim 5, wherein the air supply shutoff valve is an air circuit downstream of the leveling valve,
The air circuit is interposed on the upstream side of the bypass air circuit branch portion.

The operation of the present invention will be described. Claim 1
In the invention according to the invention, when the vehicle height is lowered, air is supplied to the auxiliary air tank side, but since the air supply shutoff opening / closing valve shuts off the air circuit from the air supply source to the air tank, the auxiliary air tank No air is supplied, and the auxiliary air tank maintains the pressure at the time of the air supply shutoff opening / closing valve shutoff operation.

That is, even when the vehicle height is lowered for a long time, air is not supplied to the auxiliary air tank until the vehicle reaches the specified pressure, and the pressure in the auxiliary air tank may increase more than necessary. Absent. As a result, when returning to the vehicle height, a certain required amount of air is supplied from the auxiliary air to the air spring, and the vehicle height can be returned to a certain appropriate height.

In the invention according to claim 2, the mechanical cut valve is opened by supplying a signal pressure from a signal pressure control valve to a signal port thereof. In the invention according to claim 3, the electromagnetic valve is opened based on an electric signal. In the invention according to claim 4, when the vehicle height is lowered, the air supply shutoff opening / closing valve shuts off the air circuit between the leveling valve and the auxiliary air tank.

In the invention according to claim 5, when the vehicle height is lowered, the air supply shutoff valve is an air circuit downstream of the leveling valve, and shuts off the upstream side of the bypass air circuit branch portion to the air circuit. .

[0029]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a configuration of a vehicle height adjusting device in an air suspension vehicle according to a first embodiment of the present invention, and shows an air circuit for left and right air springs on the front side of the vehicle.

In this figure, the same elements as those in FIG. 4 are denoted by the same reference numerals, and the description will be simplified. In FIG. 1, the air circuit 8 communicates with one of the partitioned chambers A of the auxiliary air tank 9 via a left leveling valve 1A,
The air circuit 10 communicated with the chamber A is communicated with the left air spring 12 via the left exhaust valve 11. The air circuit 8 has the upstream side of the leveling valve 1A and the downstream side of the leveling valve 1A has the auxiliary air tank 9. A bypass air circuit 13 is connected between the bypass air circuit 13 and an electromagnetic valve 14 for supplying bypass air. The air circuit 15 includes a right leveling valve 1B. The air circuit 16 connected to the other chamber B of the auxiliary air tank 9 through the air circuit 16 is connected to the right air spring 18 via the right exhaust valve 17, and the leveling valve 1B upstream of the air circuit 15 A bypass air circuit 19 is connected between the side of the valve and the downstream side of the leveling valve 1B and upstream of the auxiliary air tank 9. The air circuit 19 is provided with an electromagnetic valve 20 for supplying bypass air, and the left exhaust valve 11 and the right exhaust valve 17 are operated by the signal pressure from the electromagnetic valve 21 for controlling the signal pressure, respectively. The signal pressure circuits 22 from the electromagnetic valve 21 are connected to each other. This signal pressure control electromagnetic valve 21
The configurations connected to the air circuit 23 connected to the air circuit 7 on the upstream side of the branch portion of the air circuits 8 and 15 are the same as those in the related art.

In the air circuit from the air supply source 6 to the auxiliary air tank 9, the exhaust valves 11, 17 are opened, the air springs 1A, 1B are opened to the atmosphere, and the air springs 1A, 1B and the auxiliary air tank 9 are shut off. An air supply shutoff valve that is closed to shut off the air supply into the auxiliary air tank 9 when the exhaust gas state is switched to the exhaust state is provided.

In this embodiment, the open / close valve for shutting off the air supply has a signal port to which a signal pressure from the electromagnetic valve 21 for signal pressure control connected to the air supply source 6 is supplied. The leveling valve 1 comprises mechanical cut valves 26A and 26B that are opened based on
Air circuits 8, 15 between A, 1B and auxiliary air tank 9
In this case, air circuits 27A and 27B branched from the air circuit 22 between the electromagnetic valve 21 for signal pressure control and the exhaust valves 11 and 17 are connected to the signal ports of the cut valves 26A and 26B. .

The operation of the first embodiment will be described. When the vehicle height is lowered, the driver's seat switch 2
The operation of 4 switches the electromagnetic valve 21 for signal pressure control from the shut-off state to the ventilation state. The signal pressure supplied from the electromagnetic valve 21 for controlling the signal pressure is applied to the exhaust valve 11,
17, and are supplied to the signal ports of the cut valves 26A and 26B, respectively.

Normally, the exhaust valves 11 and 17 supply air from the leveling valves 1A and 1B (the auxiliary air tank 9 side) to the air springs 1A and 1B, but the electromagnetic valve 21 for signal pressure control. Is supplied to the signal ports of the exhaust valves 11 and 17, the ports on the leveling valves 1A and 1B are shut off, the air springs 12 and 18 communicate with the exhaust ports, and the air springs The air in the air springs 12 and 18 is crushed by the weight of the vehicle due to the air being discharged, and the vehicle height is reduced.

On the other hand, the cut valves 26A and 26B shut off the air circuits 8 and 15. In such a state, the leveling valves 1A and 1B are in the state at the time of the bounce described in the related art, so that air tends to be supplied to the auxiliary air tank 9 side.
Since the air is shut off by A and 26B, no air is supplied to the auxiliary air tank 9, and the auxiliary air tank 9 is in a state of maintaining the pressure at the time of the cut valve shut-off operation.

When the vehicle height is restored, the electromagnetic valve 21 for controlling the signal pressure is switched from the ventilation state to the shut-off state by operating the changeover switch 24 in the driver's seat. Exhaust valves 11, 17
The air supplied to the signal port and the signal ports of the cut valves 26A and 26B are respectively discharged from the electromagnetic valves 21 for signal pressure control, and the exhaust valve 21 is returned to the normal state (the leveling valves 1A and 1B side). Air springs 12 and 18) and the cut valve 26
A and 26B are open.

By the operation of the changeover switch, the bypass air supply electromagnetic valves 14, 20 are simultaneously switched from the shut-off state to the ventilation state, and the air from the air supply source 6 is supplied to the bypass air supply electromagnetic valves 14, 20 and the leveling valve. Air is supplied from both of the air springs 12 and 1B.
8 is supplied. Solenoid valve for bypass air supply 14,
Reference numeral 20 automatically switches from the ventilation state to the cut-off state by a timer circuit 25 set in advance at a time for returning the vehicle height to the normal position.

As described above, when the vehicle height is lowered, no air is supplied to the auxiliary air tank 9, and the auxiliary air tank 9 is kept at the pressure at the time of the cut valve cutoff operation. That is, even when the vehicle height is lowered for a long time, air is not supplied to the auxiliary air tank 9 until the vehicle reaches the specified pressure, and the pressure in the auxiliary air tank 9 does not increase more than necessary. .

As a result, when returning to the vehicle height, a predetermined required amount of air is supplied from the auxiliary air tank 9 to the air springs 12, 18, so that the vehicle height can be returned to a predetermined appropriate height. FIG. 2 shows a second embodiment of the present invention. In this embodiment, an air supply shutoff valve is
Electromagnetic valves 28A, 2 that are opened based on electric signals
8B, when the vehicle height is lowered, the electromagnetic switch 21 for signal pressure control is switched from the shut-off state to the ventilation state by operating the changeover switch 24 in the driver's seat, and the electromagnetic valves 28A and 28B are closed. Be operated.

In this case, the electromagnetic valves 28A and 28B
Switching is controlled by a signal from the changeover switch 24. That is, the electromagnetic valves 28A and 28B switch the changeover switch 24 to the UP side to bring the DOW into the open state.
Switching to the N side switches to the closed state.

Therefore, also in this embodiment, the electromagnetic valves 28A and 28B shut off the air circuits 8 and 15, and no air is supplied to the auxiliary air tank 9;
Is in a state in which the pressure at the time of the electromagnetic valve shut-off operation is maintained, and has the same operation and effect as the first embodiment. still,
In each of the above embodiments, the cut valve 26A, 2
6B or the electromagnetic valves 28A, 28B are interposed in the air circuits 8, 15 between the leveling valves 1A, 1B and the auxiliary air tank 9.
The air circuits 8 and 15 downstream of the air circuits A and 1B may be interposed upstream of the bypass air circuits 13 and 19 branching to the air circuits 8 and 15 (position X in FIG. 1). May be interposed in the air circuit from the air supply source 6 to the auxiliary air tank 9.

[0042]

As described above, according to the first aspect of the present invention, regardless of the length of the elapsed time in the state where the vehicle height is lowered, the vehicle height return amount at the time of vehicle height recovery is constant and appropriate. With the amount, the vehicle height can be prevented from rising excessively, and the vehicle height can always be returned to a constant appropriate height. According to the second and third aspects of the invention, the air supply shutoff valve can be easily constituted by a mechanical cut valve or an electromagnetic valve, and the function thereof is excellent in reliability.

According to the fourth and fifth aspects of the present invention, the open / close valve for shutting off the air supply can be easily interposed at an appropriate position, and its function can be effectively exerted.

[Brief description of the drawings]

FIG. 1 is a configuration of a vehicle height adjusting device in an air suspension vehicle according to a first embodiment of the present invention, and is an air circuit diagram for right and left air springs on the front side of the vehicle.

FIG. 2 is a configuration of a vehicle height adjustment device in an air suspension vehicle according to a second embodiment of the present invention, and is an air circuit diagram for right and left air springs on the front side of the vehicle.

FIG. 3 is a side view showing a configuration of a leveling valve.

FIG. 4 is a configuration of a vehicle height adjustment device in a conventional air suspension vehicle, and is an air circuit diagram for left and right air springs on the front side of the vehicle.

[Explanation of symbols]

 1A Left leveling valve 1B Right leveling valve 8 Air circuit 9 Auxiliary air tank 10 Air circuit 11 Left exhaust valve 12 Left air spring 13 Bypass air circuit 14 Electromagnetic valve for supplying bypass air 15 Air circuit 16 Air circuit 17 Right exhaust valve 18 Right air Spring 19 Bypass air circuit 20 Electromagnetic valve for supplying bypass air 21 Electromagnetic valve for controlling signal pressure 22 Signal pressure circuit 23 Air circuit 26A, 26B Cut valve 28A, 28B Electromagnetic valve

Claims (5)

[Claims] An air spring interposed between a sprung system of a vehicle and front, rear, left and right unsprung systems to support the sprung system, and supplies air to the air spring and the air spring. A leveling valve interposed in an air circuit between the air supply source, and a leveling valve that deviates from a supply / exhaust neutral point due to a change in vehicle height. An auxiliary air tank interposed in an air circuit between the leveling valve and the air spring and an air circuit between the auxiliary air tank and the air spring are configured to adjust the vehicle height to a predetermined height. An interposed exhaust valve,
An exhaust valve selectively switchable between a ventilation state in which the air spring communicates with the auxiliary air tank and an exhaust state in which the air spring is opened to the atmosphere and the air spring and the auxiliary air tank are shut off; A bypass air circuit connected to the air circuit between the downstream side of the leveling valve and the upstream side of the auxiliary air tank by bypassing the leveling valve; and a ventilation interposed in the bypass air circuit and opening the bypass air circuit. State and
A bypass air supply opening / closing valve that is selectively switched to a shut-off state for shutting off the vehicle. The air supply opening / closing valve, which is closed to shut off the air supply into the auxiliary air tank when the air spring is opened to the atmosphere and switched to the exhaust state in which the air spring and the auxiliary air tank are shut off. A height adjustment device for an air suspension vehicle, characterized by: 2. The air supply shutoff valve has a signal port to which a signal pressure from a signal pressure control valve connected to an air supply source is supplied, and the machine is opened based on the signal pressure. The vehicle height adjusting device for an air suspension vehicle according to claim 1, comprising a dynamic cut valve. 3. The vehicle height adjusting device according to claim 1, wherein the air supply shutoff valve comprises an electromagnetic valve that is opened based on an electric signal. 4. The air supply circuit according to claim 1, wherein the air supply shutoff valve is provided in an air circuit between the leveling valve and an auxiliary air tank. Height adjustment device for air suspension vehicles. 5. The air supply shut-off valve according to claim 1, wherein the air supply shut-off valve is provided in an air circuit downstream of the leveling valve and upstream of the bypass air circuit branch to the air circuit. Item 4. A vehicle height adjusting device for an air suspension vehicle according to any one of Items 1 to 3.