JPH01218911A - Air suspension control device - Google Patents

Abstract

PURPOSE:To hold an internal pressure in high and low pressure tanks to a fixed value by opening a charge circuit supplying air, when the low pressure tank decreases its internal pressure, and releasing air to the atmosphere through a drier when the low pressure tank increases its internal pressure to not less than a preset value, in the case of a pneumatic pressure type active suspension device for a vehicle. CONSTITUTION:When a low pressure tank 6 decreases its internal pressure to a proper value or less, a charge valve 20 is opened by a signal of a pressure sensor 22, and air is supplied from a high pressure tank 3 through a bypass passage 19, properly holding the pressure. Reversely when the low pressure tank 6 increases its internal pressure to the proper value or more, exhaust valves 11, 17 are simultaneously opened by a signal of the pressure sensor 22, and air is released to the atmosphere from the exhaust valve 11 through an exhaust path 18. Here by in-circuit dry air passing, a drier 12 is regenerated. Now by a check valve 13, no high pressure air is released. Thus the high and low pressure tanks enable their internal pressure to be held to a fixed value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an air suspension control device for a vehicle, and more specifically, to an air suspension control device for a vehicle, and more particularly, to a pneumatic system for supplying and discharging compressed air to each suspension in a pneumatic active suspension mechanism. It is related to circuits.

(Prior art) Pneumatic active suspension system 1C in a vehicle is
Conventionally, a pneumatic circuit for recovering exhaust air during active control has been generally used with the intention of effectively utilizing the exhaust air.

That is, such a pneumatic circuit includes a high-pressure tank for air supply and a low-pressure tank for recovery, and these two tanks are connected via a supply/discharge path of a control valve that controls the supply and discharge of air to and from the suspension. It also has a closed circuit configuration with a compressor circuit that supplies air from the low-pressure tank to the high-pressure tank.

When supplying air to the suspension, air from the high pressure tank is supplied to the suspension under flow control by the control valve.

On the other hand, when exhaust air is discharged from the suspension engine, the exhaust air is also collected into the low-pressure tank under the amount control of Mi and the amount controlled by the control 7r.

If the internal pressure of the high-pressure tank decreases due to the supply of air to the suspension, the air converter is started to suck in the air in the low-pressure tank, and the compressed air is sent to the high-pressure tank through the compressor circuit. .

Therefore, the circulation of the supply and exhaust air by the compressor in this closed circuit sucks in air at an internal pressure (considerably higher than the internal pressure in the low-pressure tank), which results in a larger flow rate in terms of atmospheric pressure than when air is sucked in. As a result, it is possible to use a small air compressor, and the drying of the circulating air only needs to be done for a small amount of supplementary air to compensate for the amount of leakage from the circuit system including the suspension. A simple hair dryer! This is advantageous in that A1 can be used.

[Invention or problem to be solved]

By the way, according to the pneumatic circuit having a closed circuit configuration in the conventional device mentioned above, when air is discharged from the suspension! It goes without saying that the high-pressure tank internal pressure is within a predetermined range because it depends on the suspension internal pressure and the low-pressure tank internal pressure at that time, which are regulated by the control valve.
Is the flow characteristic stable even if the internal pressure of the low-pressure tank fluctuates?
There is a drawback that it cannot be ignored.

Therefore, in order to always obtain stable flow characteristics in a pneumatic circuit for such a pneumatic active suspension, this invention maintains the internal pressure of the high-pressure tank and the low-pressure tank within a certain range. It is an object of the present invention to provide a hydraulic shock absorber equipped with a pneumatic circuit that can be maintained.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a pressure detecting device for both tanks in the above-mentioned conventionally known pneumatic circuit equipped with a high pressure tank and a low pressure tank. Place them respectively.

A biased pressure tank charging circuit is provided between the two tanks without a valve device that opens in response to a low pressure tank internal pressure drop signal detected by the pressure detection device.

In addition, a check valve is disposed in the air supply circuit that communicates the supplementary air dryer and the high pressure tank, and the circuit is opened in conjunction with the exhaust valve in response to an overpressure signal of the internal pressure of the low pressure tank detected by the pressure detection 'A'. A low pressure tank exhaust circuit having a valve arrangement is provided between the low pressure tank and the dryer.

Furthermore, the high-pressure tank has a valve device that opens in conjunction with the exhaust valve in response to an overpressure signal of the high-pressure tank internal pressure detected by the pressure detection device under a situation where the low-pressure tank internal pressure is in the appropriate +E range or overpressure range. An exhaust circuit is provided between the high pressure tank and the tractor under low circuit pressure control.

(Function) A pneumatic circuit consisting of a closed circuit equipped with a high pressure tank and a low pressure tank is operated by control valves in response to detection information from various sensors installed in the vehicle (e.g. acceleration sensor, vehicle height sensor, etc.). It functions by supplying air from a high-pressure tank to the suspension, or discharging air from the suspension to a low-pressure tank to maintain the suspension of each wheel in an optimal condition.

First, the pneumatic circuit uses pressure detection devices normally placed in both tanks to detect when the internal pressure of the pneumatic tank supplied to the suspension approaches the lower limit of a preset appropriate range. The detected +tgj equipment furnace equipment signal drives the compressor, pumps out the air in the low pressure tank and pumps it into the i'I'6 ltl tank, and operates to constantly maintain the internal pressure in the high pressure tank within the appropriate +E range.

-1- For normal operation, the internal pressure of the high pressure tank is within the appropriate range or above 1! i Down, low pressure tank internal pressure or part 1iIIEiI! When the pressure drops below the ambient temperature, a signal from the device detecting these conditions opens the low pressure tank charging circuit and directs air from the high pressure tank to the low pressure tank.

On the other hand, when the internal pressure of the high-pressure tank is in the appropriate iE range and the internal pressure of the low-pressure tank is within the appropriate range J-, the air in the low-pressure tank is passed through the low-pressure tank exhaust circuit and from the exhaust valve opened to the circuit. into the atmosphere.

At this time, the exhaust path and the outside air supply path to the high pressure tank are
Since the high-pressure tank is used as a component, a backflow prevention valve disposed on the high-pressure tank side of the air supply path is balanced to prevent air from leaking from the high-pressure tank from the open exhaust valve.

The high-pressure tank discharge circuit opens the valve device in response to the signal from the pressure detection 'A blue when the low-pressure tank internal pressure is within the appropriate range or higher and the high-pressure tank internal pressure is above the appropriate range. At the same time, the air inside the high-pressure tank is released into the atmosphere through the exhaust valve, which is opened in conjunction with the above, until the internal pressure reaches the appropriate range.

(Example) The IA embodiment of the present invention will be described above.

・The control valves 2, which are arranged independently for each wheel suspension and 1 inch in an IL vehicle, are connected in parallel with an air supply path 4 from a high-pressure tank 3, and , a low pressure tank 6 is connected via an exhaust path 5.

Then, between these two tanks 3 and 6, there is an air conditioner that supplies air from the low pressure tank 6 to the high pressure tank 3.
These high pressure tanks 3. air suspension 1
control valve 2, including valve 1; It consists of a closed circuit consisting of a low-pressure tank 7 and a compressed air circulation path passing through the air compressor 7 and check valve 8 to the high-pressure tank 3.

An air compressor 10 and an exhaust valve 11 are juxtaposed to the closed circuit, and a supplementary circuit is attached to the closed circuit by connecting it to the circuit through a dryer 12 for replenishing air in the closed circuit and discharging excess air.

The supplementary air from the supplementary circuit is then supplied to the check valve 13.
The exhaust air from the closed circuit is sent to the high pressure tank 3 through the high pressure tank 3 and the high pressure tank exhaust path 15, which has an exhaust valve 14 and a throttle 15 arranged in series between the high pressure tank 3 and the dryer 12, and the low pressure tank. 6 and a low-pressure tank exhaust path 18 in which an exhaust valve 17 is inserted between the dryer 12 and the dryer 12.

Incidentally, in the case of a structure having a squeezing passage that exerts a throttling action under the opening of the exhaust valve I4, the throttling 15 is not necessarily required.

Furthermore, an oil temperature closed circuit bypass path 19 is provided between the pre-fattening tanks 3 and 6, and air is directly supplied from the high pressure tank 3 to the low pressure tank 6 by controlling the opening and closing of the charcuterie half 20 in the path 19. There is no such thing.

And each of these pulps, l11. +7 and 20, 1 and 1; As information sensors for driving and controlling the compressor 7 and IO, 1) pressure sensors 21 and 22 are arranged in both tanks 3 and 6, respectively.

According to the embodiment having such a configuration, the internal pressure in the high pressure tank 3 is set in the appropriate IF range as in the conventional means, and on the other hand, the appropriate range of internal FE in the low pressure tank 6 is set from the appropriate range internal pressure in the high pressure tank 3. Also, set it in a sufficiently low range.

The internal pressures of both tanks 3 and 6 are constantly monitored by pressure sensors 21 and 22 attached to these tanks.

The pressure sensors 21 and 22 may be of any type, such as an analog output type or a switch type.

Therefore, during the suspension control operation, when the internal pressure of the high-pressure tank 3 drops below the appropriate range, the internal pressure of the low-pressure tank 6 is within the appropriate range, when it is lower than that, and when the internal pressure is below the above-mentioned appropriate range. It is assumed that this situation will occur.

Therefore, the operating states of the control device in the case of these equal capacity modes will be sequentially explained.

That is, in a situation where the internal pressure of the high pressure tank 3 is below the appropriate IIE range and the internal pressure of the low pressure tank 6 is also below the appropriate range, the absolute amount of air in the closed pneumatic circuit is insufficient. Therefore, the information signals from the pressure sensors 21 and 22 that detect this drive the air compressor IO in the supplementary circuit, and while drying the output compressed air through the dryer 12, the check valve 13 is pushed open. In addition to supplying the high pressure tank 3, the charge valve 2
0 is opened, and air is directly supplied from the high pressure tank 3 to the low pressure tank 6 through the bypass circuit 19.

On the other hand, when the internal pressure of the low-pressure tank 6 is within the appropriate range, the air compressor 10 only supplies compressed air to the high-pressure tank 3 while the charge valve 20 remains closed. .

Further, when the internal pressure of the low pressure tank 6 is within the appropriate range, the air compressor 7 in a closed circuit is driven to supply air in the low pressure tank 3 to the high pressure tank 3 through the air supply path 9.

In the high-pressure tank 3 as well, in addition to the internal pressure state below the above-mentioned appropriate range, fluctuations and cases above the appropriate range also occur, so these are different from the above-mentioned three states of the low-pressure tank 6 in each fund. The combination situation will be explained in the Nth order.

First, the internal pressure of the high pressure tank 3 is within an appropriate range.

In addition, in a situation where the internal pressure of the low pressure tank 6 is below its appropriate range, the charge valve 20 is opened and the high pressure tank 3 is
Air is supplied from the low pressure tank 6 through the air passage 19.

On the other hand, when the internal pressure of the low-pressure tank 6 is within the appropriate range, the entire pneumatic circuit is in the properly set operating state, so each of the above-mentioned mechanisms does not operate and maintains its current state. in a state.

In addition, under the situation where the internal pressure of the low pressure tank 6 is higher than its proper level, the exhaust valves 11 and 17 are simultaneously opened.
The air in the low pressure tank 6 is discharged into the atmosphere from the exhaust valve 11 through the low pressure tank exhaust path 18.

At this time, the dry air in one circuit moves backward through the dryer 12, so that the dryer 12 is regenerated.

Of course, under this situation, the check valve 13 and the exhaust valve are closed! 4 and the charge valve 20, the air in the high pressure tank 3 and other circuits is not released.

When the internal pressure of the high-pressure tank 3 is within the appropriate range and the internal pressure of the low-pressure tank 6 is below the appropriate range, the charge valve 20 is opened to drain the air from the high-pressure tank 3 to the bypass passage 19. is transferred to the low pressure tank 6 through the tank.

On the other hand, under conditions where the internal pressure of the low pressure tank 6 is within the appropriate range, the exhaust valves 11 and 14 are opened simultaneously and the air in the high pressure tank is released into the atmosphere through the high pressure tank exhaust path 16, or at this time Since the air flowing through the exhaust passage is reduced in pressure by the throttle 15 and is thoroughly dried, the dryer 12 is regenerated when flowing back through the dryer I2.

In addition, under the situation where the internal pressure of the low pressure tank 6 is also above its appropriate range, the exhaust valves 11, 14 and 17 are opened to open the high pressure tank exhaust path 16 and the low pressure tank exhaust path! At the same time, the air in the tanks 3 and 6 is discharged into the atmosphere through the air conditioners 8, respectively, and the dryer 12 is dried and regenerated.

The operation of each mechanism under each of the above situations is as follows:
When the internal pressures of the pressure sensors 2I and 6 reach their appropriate ranges, information signals from the pressure sensors 2I and 21 detecting this result in an interruption or transition to another situation.

The operating state of each mechanical part under each situation in the above-mentioned pneumatic circuit is shown in the following operating modes: In the operating shade surface enlargement, "open" indicates open.

The following margin (effect of fl light) As described above, according to the control device of the present invention, conventional T=1+
A valve that operates based on internal pressure information signals from pressure detection devices placed in a high pressure tank and a low pressure tank, respectively, in a pneumatic circuit for a pneumatic active suspension system with a closed circuit configuration. By installing an air supply circuit consisting of a device, a compressor, etc., it is possible to maintain the pressure in both tanks at all times within an appropriate range, and each tank is provided with an independent exhaust circuit. It is possible to stabilize the overpressure state of the internal pressure of the tank by quickly exhausting external δ, and thereby, it is possible to stabilize the operating flow value characteristics of each suspension control valve during suspension control operation, which is effective and effective. It becomes possible to perform stable suspension control.

[Brief explanation of the drawing]

[The fourth page is a pneumatic circuit diagram showing an embodiment of the control device of the present invention. l...Air suspension 2...Control valve 3...High pressure tank 6...
Low pressure tank 7, IO... Air compressor II, 14.17... Exhaust valve 12... Dryer 13... Check valve 20
...Charge valve depa□'1.

Claims (1)

[Scope of Claims] An air supply circuit from a high-pressure tank to the air suspension of each wheel via a control valve, an exhaust circuit from the control valve to a low-pressure tank, and an air compressor circuit that supplies air from the low-pressure tank to the high-pressure tank. an air active suspension control mechanism consisting of a closed circuit consisting of an air compressor and an exhaust valve, and a circuit for supplying and discharging supplementary air to the closed circuit with an air compressor and an exhaust valve arranged in parallel, with the intervention of a dryer, (a) pressurizing both the tanks; (b) a low pressure tank charging circuit having a valve device that opens in response to a low pressure tank internal pressure drop signal detected by the pressure detection device is provided between the two tanks; (c) the dryer and the high pressure A low-pressure tank exhaust circuit having a check valve disposed in an air supply circuit that communicates with the tank, and a valve device that opens in conjunction with the exhaust valve in response to an overpressure signal of the low-pressure tank internal pressure detected by the pressure detection device. is provided between the low-pressure tank and the dryer, and (d) when the low-pressure tank internal pressure is in a proper range and an overpressure range, the exhaust valve is activated by an overpressure signal of the high-pressure tank internal pressure detected by the pressure detection device. An air suspension control device characterized in that a high pressure tank exhaust circuit having a valve device that opens in conjunction with the high pressure tank is attached between the high pressure tank and the dryer under low circuit pressure control.