JP6231863B2 - Air suspension system - Google Patents

Description

  The present invention relates to an air suspension system that is mounted on a vehicle such as a four-wheel automobile and adjusts the vehicle height by supplying and discharging air compressed by a compressor to and from the air suspension.

  In general, a vehicle such as a four-wheeled vehicle is equipped with an air suspension system for adjusting the vehicle height. This air suspension system includes an air suspension that adjusts the vehicle height in accordance with supply and discharge of air, a compressor that compresses air supplied to the air suspension, and a high-pressure tank that stores air compressed by the compressor. . The vehicle height is raised by supplying compressed air stored in the high-pressure tank to the air suspension (see, for example, Patent Document 1).

  On the other hand, in this prior art, when lowering the vehicle height, air is discharged from the air suspension, and the discharged air is stored in a low-pressure tank. And a compressor compresses the air which has the pressure more than the atmospheric pressure stored in the low pressure tank, and stores this compressed air in a high pressure tank. Thereby, the pressure difference between the suction side and the discharge side of the compressor can be suppressed, and the pressure when the air is compressed by the compressor can be reduced.

JP 2009-46027 A

  However, the above-described conventional air suspension system includes a high-pressure tank that stores compressed air supplied to the air suspension when the vehicle height is raised, and a low-pressure tank that stores air discharged from the air suspension when the vehicle height is lowered. The two tanks are configured.

  For this reason, when mounting an air suspension system in a vehicle, there exists a problem that the space for installing two tanks becomes large. In addition, there is a problem that the number of parts for configuring the air suspension system increases and the manufacturing cost increases.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to reduce the installation space and the manufacturing cost by reducing the number of tanks. Is to provide.

In order to solve the above-described problems, the present invention provides an air suspension that is interposed between a vehicle body and an axle and adjusts the vehicle height according to supply and discharge of air, a compressor that compresses air, and a compressor that compresses air. A tank for storing fresh air, a replenishment passage connecting the compressor and the tank, and a reflow passage that is provided in the middle of the replenishment passage to allow air flow from the compressor to the tank and prevent reverse flow. 1 check valve, a supply / discharge passage connecting the tank and the air suspension, a supply position provided in the middle of the supply / discharge passage for supplying air to the air suspension, and air in the air suspension A supply / discharge switching valve that is switched to a discharge position for discharging, and is provided between the supply / discharge switching valve and the air suspension and is provided in the middle of the supply / discharge passage. A suspension control valve for controlling the extension and contraction of the air suspension by opening and closing the supply and discharge passage, the one end being connected to said supply and discharge switching valve, and a return passage which is the other end is connected to the suction side of the compressor, An air suspension system comprising a return passage opening and closing valve provided in the middle of the return passage and opening and closing the return passage , and is connected to an intake filter that sucks in air, and the intake filter and a suction side of the compressor A second check valve that allows air flow toward the compressor and prevents reverse flow is disposed between the second passage and the other end of the return passage between the suction side of the compressor and the second check. is connected between the valve, said when lowering the vehicle height by the air suspension, switched the supply and discharge switching valve in discharge position, the suspension control valve Thus opening the supply and discharge passage by the compressor together with opening the return passage is actuated by the return passage on-off valve, to replenish the tank via pre Symbol return passage and the supply passage of air in the air suspension When the vehicle height is raised by the air suspension, the supply / discharge switching valve is switched to the supply position and the supply / discharge passage is opened by the suspension control valve, so that the compression in the tank is stopped while the compressor is stopped. It is configured to supply to the air suspension through the supply and discharge passage of air.

  According to the present invention, an air suspension system can be configured using a single tank, and the installation space can be reduced and the manufacturing cost can be reduced.

It is a circuit block diagram which shows the air suspension system by embodiment of this invention. It is a circuit block diagram which shows the state which raises a vehicle height with an air suspension. It is a circuit block diagram which shows the state which lowers vehicle height with an air suspension.

  Hereinafter, an air suspension system according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

  In the figure, reference numerals 1 and 2 denote air suspensions mounted on the vehicle. Each of the air suspensions 1 and 2 is provided between an axle and a vehicle body (both not shown), depending on supply and discharge of air. The vehicle height is adjusted. In the case of a four-wheeled vehicle, normally, a total of four air suspensions are arranged with two on the front wheel side and two on the rear wheel side, but in this embodiment, the description is simplified. Therefore, only two air suspensions 1 and 2 are shown.

  Here, in the air suspension 1, an air chamber 1C is formed between the cylinder 1A and the piston rod 1B, and the air chamber 1C is connected to a branch supply / discharge passage 9A described later. On the other hand, the air suspension 2 also has an air chamber 2C formed between the cylinder 2A and the piston rod 2B, and the air chamber 2C is connected to a branch supply / discharge passage 9B described later.

  The compressor 3 compresses the air supplied to the air suspensions 1 and 2. Here, the compressor 3 includes a compressor main body 3A and an electric motor 3B that drives the compressor main body 3A. On the suction port 3C side of the compressor 3, an intake filter 4 for removing dust and the like in the outside air sucked into the compressor main body 3A is provided. On the other hand, a supply passage 6 described later is connected to the discharge port 3D of the compressor 3.

  The tank 5 stores air compressed by the compressor 3. The discharge port 3D of the compressor 3 and the tank 5 are connected via a supply passage 6, and the compressed air discharged from the compressor 3 is stored in the tank 5 through the supply passage 6. The compressed air stored in the tank 5 is supplied to the air chambers 1C and 2C of the air suspensions 1 and 2 through a supply / exhaust passage 9 described later.

  The air dryer 7 is provided in the middle of the supply passage 6. The air dryer 7 is filled with a desiccant (not shown) such as silica gel, for example, and generates dry compressed air by adsorbing moisture contained in the compressed air discharged from the compressor 3 to the desiccant. Accordingly, the compressed air dried by passing through the air dryer 7 is stored in the tank 5, and the dried compressed air is also supplied to the air chambers 1 C and 2 C of the air suspensions 1 and 2.

  The first check valve (check valve) 8 is located between the tank 5 and the air dryer 7 and is provided in the supply passage 6. The first check valve 8 allows a flow of air (compressed air) from the compressor 3 to the tank 5 and prevents a reverse flow.

  The supply / discharge passage 9 connects between the tank 5 and the air chambers 1C and 2C of the air suspensions 1 and 2. In the supply / discharge passage 9, compressed air supplied from the tank 5 to the air suspensions 1 and 2 circulates and air discharged from the air suspensions 1 and 2 circulates. Here, the supply / discharge passage 9 is branched into two branch supply / discharge passages 9A, 9B between a supply / discharge switching valve 10 and air suspensions 1, 2, which will be described later, and one branch supply / discharge passage 9A is an air suspension. One air chamber 1 </ b> C is connected, and the other branch supply / discharge passage 9 </ b> B is connected to the air chamber 2 </ b> C of the air suspension 2.

  The supply / exhaust switching valve 10 is provided in the middle of the supply / exhaust passage 9, and the supply / exhaust switching valve 10 is constituted by an electromagnetic valve at a 3-port 2-position. Here, the supply / discharge switching valve 10 is selected between a supply position (a) for supplying air (compressed air) to the air suspensions 1 and 2 and a discharge position (b) for discharging the air in the air suspensions 1 and 2. Can be switched. For example, when the solenoid 10A is not excited, the supply / discharge switching valve 10 holds the discharge position (b) by the spring 10B, and when the solenoid 10A is excited, the supply position (a) against the spring 10B. Is switched to.

  The suspension control valve 11 is located between the air suspension 1 and the supply / exhaust switching valve 10 and is provided in the middle of the branch supply / exhaust passage 9A. The suspension control valve 11 is composed of a 2-port 2-position electromagnetic valve. Yes. The suspension control valve 11 opens the branch supply / discharge passage 9A to open the position (a) allowing air supply / discharge to the air chamber 1C of the air suspension 1, and closes the branch supply / discharge passage 9A to the air chamber of the air suspension 1. The air suspension 1 is selectively switched to a closed position (b) that shuts off supply and discharge of air, and controls the expansion and contraction of the air suspension 1. Here, for example, when the solenoid 11A is not excited, the suspension control valve 11 holds the closed position (b) for closing the branch supply / discharge passage 9B by the spring 11B, and resists the spring 11B when the solenoid 11A is excited. Then, the branch supply / discharge passage 9A is switched to the open position (a).

  The suspension control valve 12 is located between the air suspension 2 and the supply / discharge switching valve 10 and is provided in the middle of the branch supply / discharge passage 9B. The suspension control valve 12 is composed of a 2-port 2-position electromagnetic valve, like the suspension control valve 11, and has an open position (a) for opening the branch supply / discharge passage 9B and a closed position (b) for closing the branch supply / discharge passage 9B. By selectively switching between the air suspension 2 and the air suspension 2, the expansion and contraction of the air suspension 2 are controlled. Here, for example, when the solenoid 12A is not excited, the suspension control valve 12 holds the closed position (b) that closes the branch supply / discharge passage 9B by the spring 12B, and resists the spring 12B when the solenoid 12A is excited. Then, the branch supply / discharge passage 9B is switched to the open position (a).

  The return passage 13 connects between the supply / discharge switching valve 10 and the discharge port 3D of the compressor 3. This return passage 13 is used when the supply / discharge switching valve 10 holds the discharge position (b) and the suspension control valves 11, 12 are switched to the open position (a). The air exhausted from 2C is returned to the suction side (suction port 3C side) of the compressor 3.

  The return passage opening / closing valve 14 is provided in the middle of the return passage 13, and the return passage opening / closing valve 14 is constituted by a 2-port 2-position electromagnetic valve, and opens and closes the return passage 13. Here, the return passage opening / closing valve 14 has an open position (a) for opening the return passage 13 and a closed position (b) for closing the return passage 13. For example, when the solenoid 14A is not energized, When the closed position (b) is maintained and the solenoid 14A is excited, the position is switched to the open position (a) against the spring 14B.

  The second check valve 15 is provided on the intake side of the compressor 3. The second check valve 15 is disposed between the suction port 3 </ b> C of the compressor 3 and the intake filter 4. The second check valve 15 allows air flow from the intake filter 4 toward the compressor 3 and prevents reverse flow.

  The bypass passage 16 is provided between the supply passage 6 and the return passage 13. Here, one end side of the bypass passage 16 is connected in the middle of the return passage 13 at a connection portion 16A located between the supply / discharge switching valve 10 and the return passage opening / closing valve 14, and the other end side of the bypass passage 16 is A connection portion 16B located between the air dryer 7 and the first check valve 8 is connected in the middle of the supply passage 6. The bypass passage 16 is for releasing the air in the air chambers 1C, 2C of the air suspensions 1, 2 to the atmosphere by bypassing the compressor 3.

  The third check valve 17 is provided in the middle of the bypass passage 16, and the third check valve 17 allows air flow from the return passage 13 toward the supply passage 6 and prevents reverse flow. .

  The exhaust passage 18 discharges air in the air chambers 1C and 2C of the air suspensions 1 and 2 to the atmosphere. Here, one end side of the exhaust passage 18 is connected to the supply passage 6 at a connection portion 18 </ b> A located between the discharge port 3 </ b> D of the compressor 3 and the air dryer 7. The other end side of the exhaust passage 18 is opened to the atmosphere via the intake filter 4. The exhaust passage 18 allows the air discharged from the air suspensions 1 and 2 to be released into the atmosphere without being introduced into the tank 5.

  The exhaust passage opening / closing valve 19 is provided in the middle of the exhaust passage 18, and the exhaust passage opening / closing valve 19 is constituted by an electromagnetic valve at a 2-port 2-position, and opens and closes the exhaust passage 18. Here, the exhaust passage opening / closing valve 19 has an open position (a) for opening the exhaust passage 18 and a closed position (b) for closing the exhaust passage 18. For example, when the solenoid 19A is not energized, When the closed position (b) is maintained and the solenoid 19A is excited, the position is switched to the open position (a) against the spring 19B.

  The air suspension system according to the present embodiment has the above-described configuration, and the operation thereof will be described below.

  First, when the compressed air is not sufficiently stored in the tank 5, as shown in FIG. 1, the supply / discharge switching valve 10 is held at the discharge position (b), the suspension control valves 11, 12 and the return passage. The compressor 3 is operated with the on-off valve 14 and the exhaust passage on-off valve 19 held in the closed position (b).

  As a result, the compressor 3 sucks outside air through the intake filter 4, compresses the outside air, and discharges it to the supply passage 6. The compressed air is stored in the tank 5 after being dried by the air dryer 7. For example, when the pressure in the tank 5 reaches a certain pressure, the compressor 3 stops, and the tank 5 can be filled with sufficient compressed air.

  Next, when raising the vehicle height, the return passage opening / closing valve 14 is held in the closed position (b) and the exhaust passage opening / closing valve 19 is closed as shown in FIG. 2 with the compressor 3 stopped. Hold in (b). By exciting the solenoid 10A of the supply / discharge switching valve 10 in this state, the supply / discharge switching valve 10 is switched to the supply position (a), and the solenoids 11A, 12A of the suspension control valves 11, 12 are excited, The suspension control valves 11 and 12 are switched to the open position (a).

  As a result, the compressed air in the tank 5 is led out to the supply / discharge passage 9, and this compressed air is supplied into the air chamber 1C of the air suspension 1 through the branch supply / discharge passage 9A and air is supplied through the branch supply / discharge passage 9B. The air is supplied into the air chamber 2 </ b> C of the suspension 2. As described above, the compressed air stored in the tank 5 can be supplied into the air chambers 1C and 2C and the air suspensions 1 and 2 can be quickly expanded. Compared with the case where the air suspensions 1 and 2 are supplied to the air chambers 1C and 2C, the vehicle height can be increased quickly.

  After the vehicle height raising operation is completed, as shown in FIG. 1, the energization to the solenoid 10A of the supply / discharge switching valve 10 is stopped to switch the supply / discharge switching valve 10 to the discharge position (b) and the suspension control valve. The energization of the solenoids 11A, 12A to the solenoids 11A, 12A is stopped to switch the suspension control valves 11, 12 to the closed position (b). As a result, the branch supply / discharge passages 9A and 9B are closed and the air chambers 1C and 2C of the air suspensions 1 and 2 are sealed, so that the air suspensions 1 and 2 are maintained in the extended state and the vehicle height is increased. be able to.

  On the other hand, when lowering the vehicle height, as shown in FIG. 3, the supply / discharge switching valve 10 is held at the discharge position (b) and the exhaust passage opening / closing valve 19 is held at the closed position (b). In this state, the solenoid 14A of the return passage opening / closing valve 14 is excited to switch the return passage opening / closing valve 14 to the open position (a), and the solenoids 11A, 12A of the suspension control valves 11, 12 are excited, The suspension control valves 11 and 12 are switched to the open position (a). Further, the compressor 3 is operated.

  Thereby, the air in the air chamber 1C of the air suspension 1 is led out from the branch supply / discharge passage 9A to the return passage 13, and the air in the air chamber 2C of the air suspension 2 passes from the branch supply / discharge passage 9B to the return passage 13. Derived. The air led out to the return passage 13 is guided to the suction port 3C of the compressor 3 without being released into the atmosphere, and is compressed by the compressor 3 and then into the tank 5 through the supply passage 6 and the air dryer 7. To be replenished. As a result, air is discharged from the air chambers 1C and 2C of the air suspensions 1 and 2 and the air suspensions 1 and 2 shift to the contracted state, whereby the vehicle height can be lowered.

  Thus, in the air suspension system according to the present embodiment, the air discharged from the air chambers 1C and 2C of the air suspensions 1 and 2 is compressed by the compressor 3 without being released into the atmosphere and stored in the tank 5, A closed circuit for supplying the compressed air stored in the tank 5 to the air suspensions 1 and 2 is configured.

  After the vehicle height lowering operation is completed, as shown in FIG. 1, the energization of the suspension control valves 11 and 12 to the solenoids 11A and 12A is stopped, and the suspension control valves 11 and 12 are switched to the closed position (b). As a result, the branch supply / discharge passages 9A and 9B are closed and the air chambers 1C and 2C of the air suspensions 1 and 2 are sealed, so that the vehicle height is lowered by maintaining the air suspensions 1 and 2 in the contracted state. Can be kept in a state.

  As described above, the air discharged from the air suspensions 1 and 2 when the vehicle height is lowered is guided to the suction port 3C of the compressor 3 through the return passage 13, and then compressed by the compressor 3 and stored in the tank 5. Therefore, a tank (low pressure tank) for storing the air discharged from the air suspensions 1 and 2 can be made unnecessary.

  Therefore, the air suspension system according to the present embodiment can be configured using one tank 5, and the number of parts of the entire system can be reduced. As a result, the entire air suspension system can be reduced in size and weight, and the installation space when mounted on a vehicle can be reduced. Moreover, the assembly property to the vehicle can be improved and the manufacturing cost can be reduced.

  Moreover, the air chambers 1C and 2C of the air suspensions 1 and 2 normally have a pressure higher than the atmospheric pressure, so that the air discharged from the air suspensions 1 and 2 is guided to the suction port 3C of the compressor 3. Thus, the pressure difference between the suction port 3C side and the discharge port 3D side of the compressor 3 can be suppressed, and the pressure when air is compressed by the compressor 3 can be reduced.

  On the other hand, when the pressure in the air chambers 1 </ b> C and 2 </ b> C of the air suspensions 1 and 2 is lower than the atmospheric pressure, outside air is sucked into the compressor 3 through the intake filter 4. Thereby, the compressor 3 compresses the outside air and discharges it to the supply passage 6, and the compressed air discharged to the supply passage 6 is dried by the air dryer 7 and then stored in the tank 5.

  Next, for example, when the vehicle height is lowered rapidly in order to stabilize the vehicle's turning posture, the supply / discharge switching valve 10 is held at the discharge position (b) and the return passage opening / closing valve 14 is closed. Hold in position (b). In this state, the solenoid 19A of the exhaust passage opening / closing valve 19 is excited to switch the exhaust passage opening / closing valve 19 to the open position (a), and the solenoids 11A, 12A of the suspension control valves 11, 12 are excited, The suspension control valves 11 and 12 are switched to the open position (a). At this time, the compressor 3 is stopped.

  Thereby, the air in the air chamber 1C of the air suspension 1 is led out from the branch supply / discharge passage 9A to the return passage 13, and the air in the air chamber 2C of the air suspension 2 passes from the branch supply / discharge passage 9B to the return passage 13. Derived. Then, the air led out to the return passage 13 passes through the bypass passage 16 and is led to the exhaust passage 18 via the air dryer 7 and is discharged from the exhaust passage 18 into the atmosphere. As a result, air can be rapidly discharged from the air chambers 1C and 2C of the air suspensions 1 and 2, and the vehicle height can be rapidly lowered.

  On the other hand, when the vehicle height is lowered rapidly, the air discharged from the air suspensions 1 and 2 flows from the bypass passage 16 through the air dryer 7 to the exhaust passage 18. Thereby, moisture can be removed from the desiccant filled in the air dryer 7, and the desiccant can be regenerated.

  Thus, in the air suspension system according to the present embodiment, when the vehicle height is raised by the air suspensions 1 and 2, the compressed air previously stored in the tank 5 is supplied to the air chamber 1 </ b> C of the air suspensions 1 and 2 through the supply / discharge passage 9. , 2C. Thereby, compared with the case where the air compressed with the compressor 3 is supplied directly to the air suspensions 1 and 2, for example, compressed air can be supplied rapidly and the vehicle height can be raised rapidly.

  Further, when the vehicle height is lowered by the air suspensions 1 and 2, the air in the air chambers 1C and 2C of the air suspensions 1 and 2 is guided to the suction port 3C of the compressor 3 through the return passage 13 without being released into the atmosphere. After compression by the compressor 3, the tank 5 is supplied through the supply passage 6 and the air dryer 7. Thereby, the tank (low pressure tank) which stores the air discharged | emitted from the air suspensions 1 and 2 can be made unnecessary.

  For this reason, the air suspension system according to the present embodiment can be configured using a single tank 5, and the number of parts of the entire system can be reduced. As a result, the entire air suspension system can be reduced in size and weight, and the installation space when mounted on a vehicle can be reduced. Moreover, the assembly property to the vehicle can be improved and the manufacturing cost can be reduced.

  If the pressure in the air chambers 1C and 2C of the air suspensions 1 and 2 is lower than the atmospheric pressure when the vehicle height is lowered, the compressor 3 sucks outside air through the intake filter 4 and compresses the outside air. Can be stored in the tank 5. Therefore, sufficient compressed air can always be stored in the tank 5, and the vehicle height can be adjusted by the air suspensions 1 and 2.

  Further, when the return passage opening / closing valve 14 is switched to the closed position (b) when the air is discharged from the air suspensions 1 and 2, the air introduced from the air suspensions 1 and 2 to the return passage 13 is bypassed. The air can be guided from the passage 16 to the exhaust passage 18 via the air dryer 7 and discharged from the exhaust passage 18 into the atmosphere.

  As a result, the vehicle height can be lowered rapidly by rapidly discharging air from the air chambers 1C and 2C of the air suspensions 1 and 2 to reduce the air suspensions 1 and 2. Further, the air discharged from the air suspensions 1 and 2 flows from the bypass passage 16 through the air dryer 7 to the exhaust passage 18, thereby removing moisture from the desiccant filled in the air dryer 7. Can be played.

  In the above-described embodiment, the case where the supply / discharge switching valve 10, the suspension control valves 11, 12, the return passage opening / closing valve 14, and the exhaust passage opening / closing valve 19 are each constituted by an electromagnetic pilot type direction control valve is exemplified. ing. However, the present invention is not limited to this. For example, a pneumatic pilot type or hydraulic pilot type directional control valve may be used.

  Next, the invention included in the embodiment will be described. That is, according to the present invention, an air suspension system includes an air suspension, a compressor, a tank, a supply passage connecting the compressor and the tank, and a first check valve provided in the supply passage. A supply / discharge passage connecting the tank and the air suspension, a supply / discharge switching valve provided in the middle of the supply / discharge passage, and a supply / discharge passage located between the supply / discharge switching valve and the air suspension. The suspension control valve, a return passage connecting the supply / discharge switching valve and the compressor suction side, and a return passage opening / closing valve provided in the middle of the return passage are used to lower the vehicle height by the air suspension. Sometimes, the supply / discharge switching valve is switched to the discharge position, the supply / discharge passage is opened by the suspension control valve, the return passage is opened by the return passage opening / closing valve, and the compression is performed. There by operating, and the air in the air suspension is configured to supply to the tank through without return path and supply passages to release into the atmosphere. Thereby, the air discharged from the air suspension can be introduced into the compressor, compressed by the compressor, and stored in the tank. Therefore, by configuring the air suspension system using one tank, the entire air suspension system can be reduced in size and weight, and the installation space when mounted on a vehicle can be reduced.

  Further, according to the present invention, when the vehicle height is raised by the air suspension, the supply / discharge switching valve is switched to the supply position and the supply / discharge passage is opened by the suspension control valve, so that the compressed air in the tank passes through the supply / discharge passage. The air suspension can be supplied.

  Further, according to the present invention, the pressure in the return passage is lower than the atmospheric pressure by providing the second check valve on the intake side of the compressor that allows the air flow toward the compressor and blocks the reverse flow. Sometimes, the compressor can compress the outside air taken in through the intake filter and supply it to the tank through the supply passage.

  Further, according to the present invention, an air dryer is provided in the middle of the supply passage located between the compressor and the first check valve, and one end side is connected to the return passage between the supply / discharge switching valve and the return passage opening / closing valve. And a bypass passage connected to the supply passage between the air dryer and the first check valve is provided at the other end, a third check valve is provided in the middle of the bypass passage, and a discharge side of the compressor and the air dryer are provided at one end. An exhaust passage that is connected to the replenishment passage and open to the atmosphere at the other end is provided, and an exhaust passage opening / closing valve is provided in the middle of the exhaust passage. Thereby, the vehicle height can be lowered rapidly by discharging the air in the air suspension into the atmosphere. Further, when the air discharged from the air suspension flows from the bypass passage to the exhaust passage through the air dryer, moisture is removed from the desiccant filled in the air dryer, and the desiccant can be regenerated.

DESCRIPTION OF SYMBOLS 1, 2 Air suspension 3 Compressor 4 Intake filter 5 Tank 6 Supply passage 8 First check valve 9 Supply / discharge passage 10 Supply / discharge switching valve 11, 12 Suspension control valve 13 Return passage 14 Return passage opening / closing valve 15 Second check valve 16 Bypass passage 17 Third check valve 18 Exhaust passage 19 Exhaust passage opening / closing valve

Claims (3)

An air suspension that is interposed between the vehicle body and the axle and adjusts the vehicle height according to the supply and discharge of air;
A compressor that compresses the air;
A tank for storing air compressed by the compressor;
A supply passage connecting between the compressor and the tank;
A first check valve provided in the middle of the replenishing passage to allow air flow from the compressor to the tank and prevent reverse flow;
A supply / discharge passage connecting between the tank and the air suspension;
A supply / discharge switching valve provided in the middle of the supply / discharge passage and switched between a supply position for supplying air to the air suspension and a discharge position for discharging air in the air suspension;
A suspension control valve that is located between the supply / discharge switching valve and the air suspension, is provided in the supply / discharge passage, opens and closes the supply / discharge passage, and controls expansion and contraction of the air suspension;
One end connected to the supply and discharge switching valve, and a return passage which is the other end is connected to the suction side of the compressor,
A return passage opening and closing valve provided in the middle of the return passage for opening and closing the return passage ;
An air suspension system comprising:
A second check valve that is connected to an intake air filter that sucks in air, and that allows air to flow toward the compressor and prevents reverse flow between the intake filter and the intake side of the compressor;
The other end side of the return passage is connected between a suction side of the compressor and the second check valve,
When the vehicle height is lowered by the air suspension, the supply / discharge switching valve is switched to the discharge position, the supply / discharge passage is opened by the suspension control valve, the return passage is opened by the return passage opening / closing valve, and the compressor is operated. it allows the configuration to be supplied to the tank through the front Symbol return passage and the supply passage of air in the air suspension,
When the vehicle height is raised by the air suspension, the supply / discharge switching valve is switched to the supply position and the supply / discharge passage is opened by the suspension control valve, so that the compressed air in the tank is supplied to the tank while the compressor is stopped. air suspension system comprising a structure for supplying the air suspension through supply and discharge passages. When pressure before Symbol return passage is lower than atmospheric pressure, the compressor air suspension of claim 1 comprising a structure for supplying to the tank through the supply passage to compress the ambient air sucked through the intake filter system. An air dryer which is located between the compressor and the first check valve and is disposed in the supply passage and which dries compressed air from the compressor;
A bypass passage having one end connected to the return passage between the supply / discharge switching valve and the return passage on-off valve and the other end connected to the supply passage between the air dryer and the first check valve When,
A third check valve arranged in the middle of the bypass passage to allow air flow from the return passage toward the replenishment passage and prevent reverse flow;
An exhaust passage in which one end side is connected to the supply passage between the discharge side of the compressor and the air dryer, and the other end side is opened to the atmosphere;
3. The air suspension system according to claim 1, wherein the air suspension system is provided with an exhaust passage opening / closing valve that is disposed in the middle of the exhaust passage and opens and closes the exhaust passage. 4.

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