JPH0995117A - Air suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the responsiveness of car-height control during the period of getting on and off a vehicle with high car-height. SOLUTION: The air suspension control device is provided with a compressor 10, a dryer 2, an air spring 1, a supply and discharge valve 4, an exhaust valve 5 and a check valve 37a and an orifice 37b provided in parallel between the supply and discharge valve 4 and the dryer 2 to perform car-height control. Further, between the orifice 37b and the supply and discharge valve 4, a low- pressure tank 3, an exhaust flow rate control valve 6 for controlling the rate of air flowing to the low-pressure tank 3, and a getting on and off-switching means 7a for lowering the car-height at the time when the driver gets on and off a vehicle, compared to the car-height in normal state, are provided to operate the exhaust flow rate control valve 6 by the output of the getting on and out-switching means 7a, and thus to adjust the car-height.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air suspension control device for controlling vehicle height with compressed air, and more particularly to control when a vehicle is in and out.

[0002]

2. Description of the Related Art In a conventional device of this type, the air compressed by a compressor is controlled to rise by the moisture being absorbed by a dryer and the dried air being supplied to an air spring through an air supply / exhaust valve. In addition, the compressed air supplied to the air spring passes through the air supply / exhaust valve to regenerate the moisture absorbent in the dryer with the air that has dried the moisture absorbent containing moisture in the dryer, and is discharged from the exhaust valve to control the descent. Is to do.

In order to enhance the regeneration of the moisture absorbent (silica gel etc.) of this dryer (hereinafter referred to as the regeneration of the dryer),
Japanese Patent Application Laid-Open No. 3-70615 discloses a check valve and an orifice provided in parallel after a dryer.
When the descent control is performed by this device, the compressed air supplied to the air spring is discharged from the exhaust valve through the air supply / exhaust valve, the orifice, and the dryer. There is a problem that the descending control is delayed because the compressed air is discharged through the passage. In such a configuration, it is the orifice that determines the response of the descent control. For example, if the orifice diameter is increased to improve the response of the descent control, the air flow becomes faster but the regeneration of the dryer deteriorates. As a result, moisture is accumulated in the adsorption chamber of the dryer, and increasing the orifice diameter in order to improve the response of the descent control is limited by the dryer's regeneration ability.

The responsiveness of this descent control becomes a problem, especially in a vehicle with a high vehicle height such as an RV system, because the driver has difficulty getting on and off the vehicle when getting on and off the vehicle. It occurs when considering lowering. For example, when the vehicle height is lowered when getting on and off, and when the driver next gets in the normal state from the state where the vehicle height is lowered, or when the driver gets on and there is a bad road such as a rut in front, If it is desired to raise immediately, the rise control must be performed early.

[0005]

DISCLOSURE OF THE INVENTION In the device shown above,
When the descent control is performed, the compressed air supplied to the air spring discharges the compressed air through the orifice for regeneration of the dryer, and the responsiveness of the descent control is determined by the size of the orifice. The control response becomes slow.

Particularly in an RV type vehicle, it is difficult to get on and off because of the high vehicle height. Therefore, for example, a method of providing a getting on / off switch to lower the vehicle height from the normal state can be considered.
When the boarding / alighting switch is provided in this way, if the descending control is slow, it takes time for the vehicle height to decrease by pressing the boarding / alighting switch. I have to get back to you soon.

[0007] Therefore, an object of the present invention is to reduce the vehicle height quickly so that the driver can easily get off the vehicle when the driver requests to get out of the vehicle, especially in a vehicle such as an RV system having a high vehicle height. When the passenger gets on the vehicle, the responsiveness of the vehicle height control at the time of getting on and off is improved, such as quickly returning from a state where the vehicle height has dropped to a normal state.

[0008]

As a means for solving the above-mentioned problems, the present invention provides a compressor (10) for producing compressed air as shown in FIG. 1 and a dryer (for drying air from the compressor (10)). 2), an air spring (1) for adjusting the vehicle height by compressed air, and a supply / exhaust valve (4) for supplying / discharging compressed air to / from the air spring (1).
And an exhaust valve (5) interposed between the compressor (10) and the dryer (2) for exhausting compressed air, and a check valve (37a) between the supply / exhaust valve (4) and the dryer (2). ) And an orifice (37b) in parallel, and a low pressure tank interposed between the orifice (37b) and the supply / exhaust valve (4) in an air suspension control device that controls the vehicle height by changing the rising and falling air flow rates. (3) and low pressure tank (3)
An exhaust flow rate control valve (6) for controlling the flow rate of air to the vehicle and a boarding / alighting switch means (7a) for making the vehicle height lower than a normal state when the driver gets on and off the vehicle are provided. The vehicle height is adjusted by operating the exhaust flow rate control valve (6) based on the output. Therefore, the vehicle height can be adjusted when getting on and off the vehicle.

In the second aspect, the boarding / alighting switch means (7a)
When a low vehicle height request is made for the vehicle output to get on and off, the exhaust flow rate control valve (6) is operated to introduce compressed air into the low pressure tank (3), and the exhaust flow rate control is performed when the vehicle height control is not performed thereafter. By operating the valve (6) to discharge the pressure stored in the low pressure tank (3) through the exhaust flow control valve (6) and discharging it through the exhaust valve (5), the boarding / alighting switch (7)
When a) is pushed and the driver gets out of the vehicle, the descent control is performed to lower the vehicle height. At this time, the compressed air supplied to the air spring (1) is discharged from the orifice (37).
Since it is introduced into the low-pressure tank (3) through the exhaust flow control valve (6) without passing through b), the flow rate of the air becomes faster than when it passes through the orifice (37b). It is possible to improve the control response. On the other hand, since the compressed air introduced into the low pressure tank (3) is discharged when the vehicle height control is not performed, it is possible to prevent the low pressure tank (3) from becoming full.

According to a third aspect of the present invention, the pressure detecting means (7) for detecting the pressure in the low pressure tank (3) is provided, and when the pressure detected by the pressure detecting means (7) is a predetermined pressure higher than the atmospheric pressure, the exhaust flow rate is increased. By operating the control valve (6) and the exhaust valve (5) to discharge the pressure in the low pressure tank (3), it is possible to reduce the pressure in the pressure tank (3) when the pressure is higher than the atmospheric pressure. it can.

According to the present invention, a first compressor air supply valve (8) for supplying the compressor (10) and a second compressor air supply valve (9) for introducing atmospheric pressure to the compressor (10) are provided. , If the vehicle height control is not performed,
The pressure introduced into the low-pressure tank (3) is discharged from the exhaust valve (5) by the operation of the compressor (10) via the first compressor air supply valve (8), so that it is faster than in the case of normal discharge. Can be discharged.

According to the present invention, when the pressure is discharged from the exhaust valve (5) by the operation of the compressor (10), the pressure is discharged until the pressure in the low pressure tank (3) becomes lower than the atmospheric pressure. By setting the negative pressure in the low-pressure tank (3) to be lower than the atmospheric pressure, the boarding switch (7
Low pressure tank (3) when a) is pushed and down control is performed.
It becomes possible to introduce compressed air from the air spring (1) earlier than in the case of atmospheric pressure.

According to a sixth aspect of the present invention, a first compressor air supply valve (8) and a check valve (3a) for introducing atmospheric pressure to the low pressure tank (3) are provided, and the output by the boarding / alighting switch means (7a) is released. When the rise control is performed, the rise control is performed based on the pressure in the low pressure tank (3), so that the rise control can be performed at a pressure higher than the atmospheric pressure stored in the low pressure tank (3). The responsiveness of is improved, and it is possible to quickly change from a state lower than usual to a normal state.

From the above, when the boarding / alighting switch is pressed and the driver gets out of the vehicle, the descending control is performed quickly, and when the boarding / alighting switch is released after getting on and off the vehicle, the vehicle is lowered. Since the normal state can be restored quickly, the responsiveness of the vehicle height control when getting on and off can be improved.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a system configuration diagram of the air suspension control device.

In FIG. 2, the compressor 10 is driven by an electric motor (motor) 15 to suck in the atmosphere and perform compression. The compressed air compressed by the compressor 10 is a dryer 2 and a valve member 3 that absorb moisture.
Air springs 1a, 1b, 1c which are connected to the respective wheels through the check valves 37a of No. 7 and electromagnetic valves 4a, 4b, 4c, 4d which are normally closed supply / exhaust valves and which adjust the vehicle height. , 1d. The compressed air in each of the air springs 1a, 1b, 1c, 1d passes through the solenoid valves (supply / exhaust valves) 4a, 4b, 4c, 4d, the orifice 37b of the valve member 37, the dryer 2, and the normally closed type. It is discharged into the atmosphere through the solenoid valve (exhaust valve) 5.

Orifice 37b and solenoid valves 4a, 4b, 4
A low-pressure tank 3 is provided between c and 4d, and the compressed air introduced into this low-pressure tank 3 is guided by an exhaust flow control valve 6. A pressure switch 7 is provided to detect the pressure in the low pressure tank 3. What detects this pressure is not limited to the pressure switch because it only needs to be able to detect the pressure in the low-pressure tank 3, and may be replaced by a pressure sensor or the like.

Referring to FIG. 3, a description will be given with reference to a sectional view of a compressed air supply / discharge device in which a compressor 10 for producing compressed air and a dryer 2 for drying compressed air are integrated.

The compressor 10 has an annular groove 11 on its outer peripheral surface.
It has a piston 11 in which a is formed, a piston ring 12 inserted in the annular groove 11a, and a metal cylinder 14 in which an inner hole 13 for accommodating the piston 11 is formed. A connecting rod 16 driven by an electric motor 15 is connected to the piston 11 by a connecting pin 17, and the piston 11 is slidably housed in an inner hole 13 via a piston ring 12.

The body 19 is O-shaped at the opening end of the cylinder 14.
A cylinder head portion 20 of the compressor 10 arranged via the ring 18 and an air dryer body portion 21 (hereinafter referred to as a body portion) for drying compressed air are made of a resin such as PPS (polyphenylene sulfide) having excellent heat resistance. It is integrally molded.

The cylinder head portion 20 has a suction passage 23.
(See FIG. 4), and a suction hole (not shown) that connects the suction passage 23 and the compression space 50 is formed. The compression space 50 in the cylinder 14 has a suction passage 2 formed by the piston 11 and the cylinder head portion 20.
2 and the air spring 1a via the discharge valve 26 (see FIG. 4) and the solenoid valves 4a, 4b, 4c and 4d for supplying and exhausting gas through the discharge passage 24 shown in FIG. , 1b, 1c, 1d, respectively.

A compression space 50 is formed by one end surface of the cylinder head portion 20 and the end surface of the piston 11, and the compression space 50 is formed.
An intake passage 23 for supplying atmospheric air and a discharge passage 24 for discharging the compressed air generated in the compression space 50 are formed. Further, the suction passage 23 is provided with a suction valve 25 (see FIG. 4) that opens when the pressure in the compression space becomes equal to or lower than a predetermined value, and the discharge passage 24 has a pressure in the compression space equal to or higher than a predetermined value. A discharge valve 26 (see FIG. 4) is provided which opens when it becomes. Further, the discharge passage 24 is formed with a passage 28 that communicates with an adsorption chamber 34 that absorbs moisture from the air dryer.

One end of the body portion 21 is a closed end and the other end is an open end. The closed end is the discharge passage 2
4 is communicated. A lid 31 is joined to the open end of the body portion 21 via an O-ring 30. Body part 21
Inside, a perforated plate 32 having a plurality of small holes formed at both ends is arranged, and a filter element 33 is arranged so as to face each perforated plate 32. Then, the suction chamber 34 is formed by both the perforated plates 32, and the suction chamber 3
A hygroscopic material (silica gel or the like) 35 is filled in the inside 4. A spring 36 is arranged between the opening 31a of the lid 31 and the perforated plate 32, and urges the hygroscopic material 35 in the axial direction. As a result, the hygroscopic material 35 can be brought into close contact, and the influence of pressure due to the inflow of compressed air can be prevented.

The body portion 21 is integrally formed with a mounting portion 40 having an axially elongated through hole formed therein, and the outer peripheral surface of the electric motor 15 is provided with an axially formed through hole. A band 42 integrally provided with the portion 41 is slidably loosely fitted. Then, the mounting portion 40 and the mounting portion 41
Are fastened with bolts 43 to fix the body portion 21 to the electric motor 15.

Further, in FIG. 4, an air passage 22 is formed in parallel with the body portion 21, and a valve member 37 having a filter element 47 is arranged at one end thereof.
To the other end of the solenoid valves 4a, 4b, 4c, 4d for supplying and exhausting
Is connected. When the valve member 37 supplies the compressed air dried in the adsorption chamber 34 to the air springs 1a, 1b, 1c, 1d, the check valve 37a shown in FIG.
The air springs 1a, 1b, 1c, 1d
When the compressed air is discharged from the compressed air, the compressed air is discharged to the adsorption chamber 34 through the orifice 37b. Here, the orifice 37b limits the discharge of compressed air.

A passage 39 is formed in the lid 31 so as to communicate from the opening 31a communicating with the opening end of the adsorption chamber 34 to the inlet of the valve member 37, and the compressed air dried in the adsorption chamber 34 is aired. It can be supplied to the passage 22.

A solenoid valve (supply / exhaust valve) 4 for supplying / exhausting air
Exhaust valve 5 for discharging compressed air from a, 4b, 4c and 4d
Although not shown, a solenoid valve including the exhaust flow rate control valve 6 and the like is integrally formed, and the discharge passage 24 is connected to the exhaust valve 5 for exhausting and can discharge the compressed air to the atmosphere.

Next, the operation of the supply / discharge device and the solenoid valve will be described.

First, when raising the vehicle height, the exhaust valve 5 communicating with the atmosphere is closed (hereinafter referred to as OFF). In the compressor 10, when the piston 11 descends in the inner hole 13 and the pressure in the compression space 50 becomes equal to or lower than a predetermined value, the suction valve 25 opens (hereinafter referred to as “on”) so that the atmosphere is sucked from the suction passage 23 into the compression space 50. Inhaled into. Further, when the piston 11 rises in the inner hole 13, the air in the compression space 50 is compressed, and when the pressure in the compression space 50 exceeds a predetermined value, the discharge valve 26 is turned on and discharged into the discharge passage 24. Discharge passage 2
The compressed air that has flowed out to No. 4 flows out into the body portion 21 through the ventilation hole 28. The compressed air that has flowed out into the body portion 21 passes through the small holes of the perforated plate 32 and the filter element 33.
To flow into the adsorption chamber 34. In the adsorption chamber 34, the moisture absorbing material 35 absorbs the moisture of the compressed air to dry the compressed air. Then, the compressed air is filtered by the filter element 33.
And, it flows out to the opening 31a of the lid 31 through the perforated plate 32. The compressed air flowing out to the opening 31 a flows out to the valve member 37 arranged in the air passage 22 through the passage 39, and the compressed air turns on the valve member 37. The compressed air with the valve member 37 turned on flows out to the solenoid valves 4a, 4b, 4c, 4d for supplying / exhausting which are connected via the air passage 22, and is actuated to operate from the supply / exhaust valve in the on state to the air spring 1
The vehicle height can be increased by being supplied to a, 1b, 1c and 1d. When the increase in vehicle height is completed, the electric motor 15
Is stopped, the operation of the supply / exhaust valve is turned off, the air passage 22 is closed, and the vehicle height rise is completed.

Next, when lowering the vehicle height, the supply / exhaust valve 4
By turning on a, 4b, 4c and 4d, the compressed air in the air spring is discharged. The compressed air discharged into the air passage 22 is supplied to the orifice 37 formed in the valve member 37.
The pressure is reduced by b and is discharged to the opening 31a through the passage 39. It is discharged into the discharge passage 24 through the inside of the adsorption chamber 34 from the opening 31a. At this time, the compressed air flowing into the adsorption chamber 34 is dry, and the pressure inside the adsorption chamber 34 is reduced to near atmospheric pressure, so that the moisture adsorbed by the hygroscopic material 35 and the filter element 33 evaporates. The hygroscopic material 35 and the filter element 33 are regenerated. Since the discharge valve 24 is turned off, it does not leak into the compression space and flows out to a discharge hole (not shown). The exhaust valve 5 connected to this discharge hole discharges the compressed air to the atmosphere. As a result, the compressed air in the cylinder is discharged and the vehicle height can be lowered.

Next, a flowchart of vehicle height control in the system configuration diagram in FIG. 2 will be described with reference to FIG.

First, in step 101, the microcomputer for controlling the vehicle height is initialized, and various memory clears are performed to initialize the microcomputer. In the next step 102, a sensor input signal from a vehicle height sensor (not shown) is read and stored in the memory. This vehicle height sensor outputs a voltage of 0.5V to 4.5V depending on the vehicle height state, and the A / D of this voltage is output.
The converted value is input to the microcomputer and converted into the vehicle height value. In the present invention, the vehicle height level indicates position information indicating which of the 16 levels from 0 level (lowest state) to 15 level (highest state) the vehicle height is. The level conversion by the vehicle height sensor is not limited to this, because the vehicle height control may be performed by performing the level conversion by increasing the resolution of the vehicle height value by the vehicle height sensor.

In the next step 103, the input value SH from the vehicle height sensor is filtered and a filter operation is performed to obtain filtered vehicle height data H, and this filtered value is set as the current vehicle height value.

At step 104, the state of the boarding / alighting switch 7a is judged. The boarding / alighting switch 7a is operated by the driver, and when the boarding / alighting switch 7a is pushed (turned on), the vehicle height is controlled to be lowered for boarding / alighting. Here, if the boarding / alighting switch 7a is turned on, step 105 is performed, and if it is not turned on, step 110 is performed. In step 105, the entry / exit switch 7
Since "a" is pushed, the driver has to lower the vehicle height because the driver intends to get off. Therefore, the target vehicle height EXTHB at the time of getting on and off is set and set to a value lower than the normal vehicle height (set to a value 50 mm lower than the normal vehicle height).

In step 106, it is judged whether or not the current vehicle height value H is larger than the target vehicle height EXTHB set in step 105. If it is larger, step 107 is executed, and if it is equal or smaller, step 109 is executed. Since the vehicle height is lower than the target vehicle height when getting on and off, the vehicle height control is stopped in step 109.

On the other hand, in step 107 when the target vehicle height for getting on and off is not reached, the exhaust flow rate limiting valve 6 is turned on,
In step 108, the descent control is performed.

As described above, when the boarding / alighting switch 7a is pushed to perform the descending control, the exhaust flow rate restricting valve 6 is once operated to store compressed air in the low pressure tank 3 so that the exhaust valve 5 passes through the orifice 37b. It is possible to perform the descending control earlier than the case of discharging from.

On the other hand, in step 104, the boarding / alighting switch 7a
If is not pressed, the normal target vehicle height THB is set in step 110. The setting of the target vehicle height THB is divided into three stages of high, medium and low, and is switched by a vehicle height switch (not shown). For example, the target vehicle height is set to correspond to the levels 6 to 9 of the vehicle height sensor 6, and the vehicle height value is 80 mm at the tire position.
Is set as the target value (this value changes depending on the mounting position of the vehicle height sensor). By using a switch in which the vehicle height switch and the boarding / alighting switch 7a are integrated, the cost can be reduced.

In step 111, it is judged whether or not the current vehicle height value H is larger than a value obtained by adding the dead zone α to the set target vehicle height THB, and the current vehicle height value H is the target vehicle height TH.
If it is larger than the value obtained by adding the dead zone α to B, step 112 is carried out, and if it is equal or smaller, step 113 is carried out. In step 112, since the current vehicle height is higher than the target value, the descent control is performed. This dead zone α is the start dead zone αs (10 m when the vehicle height is controlled.
m) is set and the end dead zone αe (5 mm) is set when the vehicle height control is not performed, thereby preventing hunting at the start / end of the vehicle height control.

In step 113, the current vehicle height value H
Is smaller than a value obtained by subtracting the dead zone α from the target vehicle height THB, and the current vehicle height value H is the target vehicle height THB.
If it is smaller than the value obtained by subtracting the dead zone α from, the step 114 is executed. In this step 114, the current vehicle height is lower than the target value, and therefore the ascending control is executed. Further, if the vehicle height data is in the dead zone of the target vehicle height (H + α ≧ H ≧ H−α), the routine proceeds to step 115. In step 115, the determination is made based on the state of the pressure switch 7 in which the pressure in the low pressure tank 3 is switched to the value obtained by adding a predetermined value to the atmospheric pressure. The pressure switch 7 is set to be turned on when the pressure reaches a value obtained by adding a predetermined value to the atmospheric pressure, and switches to have a hysteresis at the predetermined pressure. If the pressure switch 7 is even on, step 116 is performed. If it is not turned on, step 118 is performed and neither the rising control nor the falling control is performed. At step 116, the exhaust flow rate control valve 6 is turned on, and at step 117, the exhaust valve 5 is turned on to set the exhaust flow rate control valve 6 and the exhaust gas in the dead zone where the vehicle height control of the pressure in the low pressure tank 3 is not performed. By operating the valve 5 and discharging, the low pressure tank 3
The internal pressure can be relieved. After that, when the processes up to step 118 are completed, the process returns to step 102 and the same process of the main routine is repeated.

From the above, it is possible to perform the vehicle height control for controlling the vehicle height within a fixed range by controlling the vehicle height up and down. For example, if the vehicle height control is specifically explained, if the vehicle height of level 5 or less is detected at a certain ratio or more within a certain time when the target vehicle height is medium, then the vehicle height average is compared with the target vehicle height. Since the vehicle height is too low, the vehicle height increase control is performed. This rising control continues until the vehicle height of level 6 or higher is detected at a fixed ratio or higher within a fixed time. In the present embodiment, when a vehicle height value of 70 mm or less in which the control start dead zone (10 mm) is added to the target vehicle height is detected at a certain ratio or more within a certain period of time, the average vehicle height is too low with respect to the target vehicle height. Therefore, the vehicle height increase control is performed. Then, the ascending control continues until a vehicle height of 75 mm or more, in which the dead zone (5 mm) of the end condition is added to the target vehicle height, is detected at a certain ratio or more within a certain time. In this way, by making a difference between the control start dead zone (10 mm) and the end dead zone (5 mm), hunting at the start and end of vehicle height control is prevented.

Next, FIG. 6 which is the second embodiment will be described.

This drawing is obtained by adding two normally closed solenoid valves to the configuration diagram of FIG. That is, the first compressor air supply valve 8 is provided between the low pressure tank 3 and the compressor 10.
And a second compressor air supply valve 9 for introducing atmospheric pressure to the compressor 10. Here, the compressor 10 introduces atmospheric air through the second compressor air supply valve 9 to generate compressed air. FIG. 7 shows the control in this configuration.

In FIG. 7, steps 201 to 214 are the same as the steps 101 to 114 shown in FIG.
Let's start with.

In step 215, the pressure state of the low-pressure tank 3 is detected by the pressure switch 7 at this time, although the ascending and descending control is not performed. Here, it is determined whether or not the pressure in the low-pressure tank 3 is higher than the pressure γ lower than the atmospheric pressure. If the pressure γ is higher than the pressure γ, step 219 is performed, and if the pressure γ is equal to or lower than the pressure γ, the step 219 is performed. At 222, the vehicle height is not controlled. On the other hand, in steps 219 to 221, the first compressor air supply valve 8, the exhaust valve 5, and the compressor 10 are turned on, so that the pressure stored in the low-pressure tank 3 when the vehicle height control is not performed is reduced. By the operation of 10, the exhaust gas can be discharged from the exhaust valve 5 via the first compressor air supply valve 8. Further, when the pressure in the low-pressure tank 3 is released by operating the compressor 10, if the pressure γ lower than the atmospheric pressure is released, when the boarding / alighting switch 7a is pressed again and the descending control at the boarding / alighting is performed, the low-pressure tank 3 Since the pressure of 3 is a negative pressure lower than atmospheric pressure,
Compressed air can be introduced earlier than when it is introduced from atmospheric pressure, and the responsiveness of descent control is improved.

Further, a third embodiment shown in FIG. 8 will be described.

This figure shows that the first compressor air supply valve 8 and the low pressure tank 3 are provided with a check valve 3a, as shown in FIG.
This control is shown in FIG. 9 in addition to the configuration diagram of FIG.

In FIG. 9, steps 301 to 312 are the same as the processing from step 101 to step 112 shown in FIG. 5 up to the step of performing the descending control. Therefore, step 313 will be described.

In step 313, it is judged whether or not the current vehicle height value H is smaller than a value obtained by subtracting the dead zone α from the target vehicle height THB. The control is not performed in step 316 because it is in the dead zone of the ascent and descent control. On the other hand, when the current vehicle height value H is smaller than the value obtained by subtracting the dead zone α from the target vehicle height THB, step 314
Then, the first compressor air supply valve 8 is turned on, and step 31
At 5 the rise control is performed. In this way, by operating the first compressor air supply valve 8 to perform the rising control, the pressure stored in the low-pressure tank 3 is used to perform the rising control by the descending control at the time of getting on / off the vehicle. Responsiveness of the rising control becomes faster than that in the case of performing the rising control. Also,
When the pressure in the low-pressure tank 3 disappears and becomes equal to the atmospheric pressure during the rise control, the rise control is performed by introducing the atmosphere into the compressor 10 from the check valve 3a provided in the low-pressure tank 3. Will be possible.

From the above, the boarding / alighting switch for detecting the driver's request for boarding / alighting is provided, and when the boarding / alighting switch is pushed, the compressed air supplied to the air spring is stored in the low pressure tank, so that the orifice is opened. The descent control becomes quicker than the case of being discharged through. The pressure stored in the low pressure tank is discharged through the exhaust valve when the vehicle height control is not performed, so that the pressure in the low pressure tank is prevented from becoming full.

Further, the pressure stored in the low-pressure tank becomes faster when discharged by the operation of the compressor than in the case where discharge is performed normally, and furthermore, by releasing the pressure in the low-pressure tank to a negative pressure, When the descending control at the time of getting on and off is performed, it becomes possible to quickly introduce the compressed air into the low pressure tank.

Furthermore, by using the pressure stored in the low-pressure tank by the descent control at the time of getting on and off, when the ascending control is performed, the responsiveness becomes faster than the ascending control by introducing the atmospheric pressure.
It is possible to improve the responsiveness of the vehicle height control when getting on and off.

[0054]

As described above, the boarding / alighting switch for detecting the driver's request for boarding / alighting is provided, and when the boarding / alighting switch is pressed, the compressed air supplied to the air spring by the vehicle height control is By once controlling the exhaust flow rate control valve and storing it in the low pressure tank, the lowering control becomes faster than when compressed air is discharged through the orifice.

In this case, the pressure stored in the low-pressure tank is discharged through the exhaust valve when the vehicle height control is not performed, so that the pressure in the low-pressure tank can be prevented from becoming full. Also, at this time, if the discharge is performed by the operation of the compressor, it will be faster than when discharging normally,
Moreover, by releasing the pressure in the low-pressure tank to a pressure lower than the atmospheric pressure by the compressor, compressed air can be introduced into the low-pressure tank quickly when the descending control at the time of getting on and off is performed again.

Further, if the pressure stored in the low pressure tank is used for increasing control by the descending control at the time of getting on and off, the pressure becomes higher than the case where the atmospheric pressure is introduced into the compressor to perform the increasing control. Control becomes faster.

From the above, when the boarding / alighting switch is pressed and the driver gets out of the vehicle, the descent control can be performed quickly, and when the boarding / aboarding switch is released by the driver, the vehicle is Since the lowered state can be quickly returned to the normal state, the responsiveness of the vehicle height control when getting on and off can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an outline of an air suspension control device of the present invention.

FIG. 2 is a configuration diagram of an air suspension control device according to a first embodiment of the present invention.

FIG. 3 is a sectional view of a compressed air supply / discharge device in the air suspension control device.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

5 is a flowchart of vehicle height control in the configuration of FIG.

FIG. 6 is a configuration diagram of an air suspension control device according to a second embodiment of the present invention.

FIG. 7 is a flowchart of vehicle height control in the configuration of FIG.

FIG. 8 is a configuration diagram of an air suspension control device according to a third embodiment of the present invention.

9 is a flowchart of vehicle height control in the configuration of FIG.

[Explanation of symbols]

 1 Air Spring 2 Dryer 3 Low Pressure Tank 4 Solenoid Valve (Supply / Exhaust Valve) 5 Solenoid Valve (Exhaust Valve) 6 Solenoid Valve (Exhaust Flow Control Valve) 7 Pressure Switch 7a Boarding Switch 8 First Compressor Air Supply Valve 9 Second Compressor air supply valve 10 Compressor

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Naoki Yamada 2-1-1 Asahi-cho, Kariya City, Aichi Aisin Seiki Co., Ltd.

Claims (6)

[Claims] 1. A compressor for producing compressed air, a dryer for drying the air from the compressor, an air spring for adjusting a vehicle height by the compressed air, and a supply / exhaust valve for supplying / discharging compressed air to / from the air spring. And an exhaust valve interposed between the compressor and the dryer to exhaust compressed air, and a check valve and an orifice provided in parallel between the air supply / exhaust valve and the dryer to raise and lower air. In an air suspension control device for controlling a vehicle height by changing a flow rate, a low pressure tank interposed between the orifice and the supply / exhaust valve, an exhaust flow rate control valve for controlling a flow rate of air to the low pressure tank, and a vehicle A boarding / alighting switch means is provided for making the height lower than the normal state when the driver gets on and off, and the exhaust flow control valve is operated by the output of the boarding / alighting switch means to adjust the vehicle height. An air suspension control device characterized in that 2. When the output of the boarding / alighting switch means demands a low vehicle height for getting on and off, the exhaust flow rate control valve is operated to introduce compressed air into the low pressure tank, and the vehicle height control is not performed thereafter. The air suspension control device according to claim 1, wherein the pressure stored in the low-pressure tank is discharged through the exhaust valve by operating the exhaust flow control valve. 3. A pressure detecting means for detecting the pressure in the low pressure tank is provided, and the exhaust flow rate control valve and the exhaust valve are operated when the pressure detected by the pressure detecting means is a predetermined pressure higher than atmospheric pressure. The air suspension control device according to claim 1, wherein the pressure in the low pressure tank is discharged. 4. A first compressor air supply valve for supplying to the compressor, and a second compressor air supply valve for introducing atmospheric pressure to the compressor are provided, and when the vehicle height control is not performed, The air suspension control device according to claim 1, wherein the pressure stored in the low-pressure tank is discharged from the exhaust valve by the operation of the compressor via the first compressor air supply valve. 5. The discharge according to claim 4, wherein when the pressure is discharged from the exhaust valve by the operation of the compressor, the pressure is discharged until the pressure in the low-pressure tank becomes lower than the atmospheric pressure. Air suspension control device. 6. The low pressure tank when the first compressor air supply valve and a check valve for introducing atmospheric pressure to the low pressure tank are provided, and when the output by the boarding / alighting switch means is released to perform a rising control. The air suspension control device according to claim 1, wherein the rising control is performed based on the internal pressure.