JP2007182197A - Vehicle height adjustment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a delay of vehicle height adjustment caused by fluctuation of a pressure of a pressure-accumulation tank. <P>SOLUTION: The vehicle height adjustment device 10 has a compressor 16 mounted on the vehicle; the pressure-accumulation tank 18 for pressure-accumulating compressed air compressed by the compressor; air springs 12-15 fed with the compressed air to adjust the vehicle height; a vehicle height sensor 22 for detecting the vehicle height of the vehicle; a pressure sensor for detecting the pressure fed to the air springs 12-15; and a control part 24. Then, the control part 24 operates difference of the vehicle height obtained by subtracting actual vehicle height detected by the vehicle height sensor 22 from the previously set target vehicle height and switches an air feed source for feeding the compressed air to the air springs 12-15 from the pressure-accumulation tank 18 to the compressor 16 based on a threshold value obtained from the corresponding relationship between the difference of the vehicle height and the pressure detected by the pressure sensor 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle height adjusting device, and more particularly to a vehicle height adjusting device that accumulates compressed air compressed by a compressor in an accumulator tank and supplies the compressed air of the accumulator tank to an air spring to adjust the vehicle height.

  In the vehicle height adjustment device that adjusts the vehicle height by the air pressure of the air spring, for example, while the compressed air from the compressor is filled into the accumulator, the pressure difference between the pressure in the accumulator tank and the air spring exceeds the threshold value. Compressed air from the accumulator tank is supplied to the air spring, and when the pressure difference between the pressure in the accumulator tank and the air spring reaches a threshold value, switching is performed so that compressed air from the compressor and the accumulator tank is supplied to the air spring (for example, , See Patent Document 1).

Further, in this vehicle height adjusting device, when the pressure of the air spring decreases, the compressed air in the pressure accumulating tank is filled into the air spring due to the pressure difference between the pressure accumulating tank and the air spring. When the pressure falls below the threshold value, the amount of air supplied from the pressure accumulation tank to the air spring decreases, so that the compressor is driven and compressed air generated by the compressor is supplied to the air spring and the pressure accumulation tank.
JP 2001-246919 A

  However, in the conventional vehicle height adjusting device, when the compressed air of the pressure accumulating tank is supplied to the air spring, the pressure of the pressure accumulating tank is not always constant, and the air supply amount varies depending on the tank pressure. It is difficult to predict the vehicle height adjustment amount due to the pressure of the vehicle.

  Since the amount of air filled in the accumulator tank is finite depending on the tank capacity (volume), for example, when the vehicle height is raised only by the pressure from the accumulator tank and the amount of increase when performing control is large, the air in the accumulator tank The pressure in the pressure accumulator tank becomes low due to insufficient amount. After that, when the compressor is driven and the compressed air from the compressor is supplied to the air spring and the accumulator tank to raise the vehicle height to the target vehicle height, the compressor pressure is filled in the accumulator tank and the tank pressure rises. During this time, the amount of compressed air supplied to the air spring is reduced, which causes a problem that the speed until reaching the target vehicle height is reduced.

  In view of the above circumstances, an object of the present invention is to provide a vehicle height adjusting device that solves the problem.

  In order to solve the above problems, the present invention has the following means.

  According to a first aspect of the present invention, there is provided a compressor mounted on a vehicle, a pressure accumulation tank that accumulates compressed air compressed by the compressor, an air spring that is supplied with compressed air and adjusts a vehicle height, and a vehicle of the vehicle A vehicle height sensor for detecting a height, a pressure sensor for detecting the pressure of compressed air supplied to the air spring, and a vehicle height obtained by subtracting an actual vehicle height detected by the vehicle height sensor from a preset target vehicle height. An air supply for supplying compressed air to the air spring based on a threshold value obtained from a calculating means for calculating a difference, and a vehicle height difference calculated by the calculating means and a pressure detected by the pressure sensor Air supply source switching means for switching the source from the pressure accumulating tank to the compressor.

  According to a second aspect of the present invention, the air supply source switching means stores a data map that represents the vehicle height difference with respect to the pressure in the accumulator tank in a plurality of areas, and a data map stored in the storage means. Region determining means for determining which region includes a threshold value obtained from the relationship between the pressure detected by the pressure sensor and the vehicle height difference, and depending on the region determined by the determining means Adjustment range setting means for setting the vehicle height adjustment range by the compressed air from the pressure accumulation tank, and the compressed air from the pressure accumulation tank until the vehicle height adjustment range set by the adjustment range setting means is adjusted. When the adjustment of the vehicle height adjustment range is completed by supplying to the air spring, the vehicle height adjusting hand that switches the air supply path so that the compressed air from the compressor is supplied to the air spring. And having a, the.

  According to a third aspect of the present invention, the vehicle height adjusting means includes a tank control valve provided in a system path communicating with the pressure accumulating tank, and a pressure in the pressure accumulating tank that is greater than or equal to a predetermined value. And the compressed air from the pressure accumulating tank is supplied to the air spring, and when the pressure of the compressed air supplied from the pressure accumulating tank drops below a predetermined value, the valve is closed and the system path is shut off. The vehicle height adjustment range set by the adjustment range setting means is adjusted by a pilot valve, a pressure accumulation control valve that supplies compressed air from the compressor to the pressure accumulation tank via the pilot valve and the tank control valve. Until the tank control valve is opened, compressed air from the pressure accumulation tank is supplied to the air spring, and when the vehicle height adjustment by the vehicle height adjustment means is completed, the pressure accumulation control valve is opened and the compressor is compressed. And control means for supplying to the accumulator tank compressed air from and having a.

  According to a fourth aspect of the present invention, the vehicle height adjusting means includes a tank control valve provided in a first system line communicated with the pressure accumulating tank, a tank control valve provided in the first system path, and the pressure accumulating tank. When the pressure is higher than a predetermined value, the valve is opened and compressed air from the pressure accumulating tank is supplied to the air spring. When the pressure of the compressed air supplied from the pressure accumulating tank drops below a predetermined value, the valve is closed. A pilot valve that shuts off the first system path; a pressure control valve that is provided in a second system path that communicates with the pressure storage tank; and that supplies compressed air from the compressor to the pressure storage tank; and the adjustment range Until the vehicle height adjustment range set by the setting means is adjusted, the tank control valve is opened to supply the compressed air from the accumulator tank to the air spring, and the vehicle height adjustment by the vehicle height adjustment means is completed. If the pressure accumulation control valve is And having a control means for supplying to the accumulator tank compressed air from the compressor and the valve.

  According to the present invention, the vehicle height difference obtained by subtracting the actual vehicle height detected by the vehicle height sensor from the preset target vehicle height is calculated, and the calculated vehicle height difference and the pressure of the accumulator tank detected by the pressure sensor are calculated. In order to switch the air supply source for supplying compressed air to the air spring from the compressor to the accumulator tank based on the threshold value obtained from the correspondence relationship with, for example, when the vehicle height difference is relatively large with respect to the pressure of the accumulator tank, Alternatively, when the pressure in the pressure accumulation tank is relatively small with respect to the vehicle height difference, the supply from the pressure accumulation tank is not performed up to the target vehicle height, and the vehicle height lower than the target vehicle height obtained from the pressure accumulation tank pressure and the data map ( For example, it is possible to prevent the vehicle height adjustment operation from being delayed by early switching to the compressor at the target vehicle height of -5 mm.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a system diagram showing an embodiment of a vehicle height adjusting apparatus according to the present invention. As shown in FIG. 1, the vehicle height adjusting device 10 is incorporated in an air suspension system mounted on a vehicle such as an automobile, and each air (four wheels in this embodiment) is supported by air pressure. The springs 12 to 15, the compressor 16 that generates compressed air, the pressure accumulation tank 18 that accumulates compressed air, the pressure sensor 20, the vehicle height sensor 22, the control unit 24, and the compressed air are supplied to the air springs 12 to 15. And an air supply system 30 for supplying to the air.

  The pressure sensor 20 detects the pressure of the air supply path 30 and outputs the pressure detection signal to the control unit 24. The vehicle height sensor 22 detects the actual vehicle height of the vehicle and outputs a vehicle height detection signal to the control unit 24.

  Vehicle height adjustment valves 32 to 35 that control the supply of compressed air to the air springs 12 to 15 are arranged in the air supply system path 30. Further, a tank control valve 42 and a pilot valve 44 for introducing the pressure of the branch system path 40 through the pilot pressure introduction system path 43 are arranged in the branch system path 40 branched from the air supply system path 30. ing. In addition, a tank pressure accumulation control valve 48 that opens the pilot valve 44 at the time of pressure accumulation is arranged in the pressure accumulation path 46 branched from the air supply path 30.

  The vehicle height adjustment valves 32 to 35, the tank control valve 42, and the tank pressure control valve 48 are normally closed solenoid valves that are opened by excitation of solenoids by control signals from the control unit 24.

  The control unit 24 controls the driving of the compressor 16 and controls the opening and closing of each control valve disposed in the air supply path 30 based on data detected by the pressure sensor 20 and the vehicle height sensor 22. The memory (storage means) 50 of the control unit 24 includes an air supply source that supplies compressed air to the air spring based on a threshold value obtained from the correspondence relationship between the vehicle height difference and the pressure detected by the pressure sensor 20. A control program (air supply source switching means) for switching from the accumulator tank 18 to the compressor 16 and a data map 52 representing the relationship between the tank pressure and the vehicle height difference shown in FIG. 2 are stored.

  In the vehicle height raising control process executed by the control unit 24, initially, the vehicle height is adjusted by the pressure of the pressure accumulating tank 18, and control is performed to switch to vehicle height adjustment by the pressure of the compressor 16 as the pressure of the pressure accumulating tank 18 decreases. The switching timing is determined by comparing the threshold corresponding to the detected vehicle height difference and the tank pressure with the data map 52 to determine the use area of the compressor 16. And the control part 24 complete | finishes a vehicle height raising control process, when the actual vehicle height measured by the vehicle height sensor 22 reaches target vehicle height.

  The target vehicle height differs depending on the mode (high mode, normal mode, low mode) set by a vehicle height setting switch (not shown) operated by the driver.

  In addition, when the actual vehicle height maintains the target vehicle height, the control unit 24 performs tank filling control so that the pressure accumulation tank 18 is filled with compressed air generated by the compressor 16 without adjusting the vehicle height. Do. In this tank filling control, the tank control valve 42 and the tank pressure control valve 48 are opened while the vehicle height adjustment valves 32 to 35 are closed. Therefore, the compressed air from the compressor 16 is supplied to the pilot chamber of the pilot valve 44 via the air supply system path 30 and the pressure accumulation system path 46 to open the pilot valve 44. Thereby, the compressed air from the compressor 16 is filled into the pressure accumulating tank 18 via the branch line 40. And when the pressure sensor 20 detects an upper limit pressure, tank filling control is complete | finished.

  As described above, the pressure accumulation tank 18 is supplemented with the compressed air generated by the compressor 16 when the vehicle height is not adjusted, so that the tank pressure PT does not decrease.

  The pilot valve 44 is closed so that the tank pressure PT opens when the tank pressure PT is equal to or higher than a predetermined pressure obtained by adding ΔP (tuning allowance) to the standard set pressure P0 of each air spring 12 to 15 (PT> P0 + ΔP). The spring constant of the spring member is set. Therefore, when the tank pressure PT falls below, for example, the lower limit pressure Pf (predetermined pressure) (PT <P0 + ΔP), the pilot valve 44 is closed and the supply of compressed air from the pressure accumulating tank 18 is stopped. ing. Therefore, when the tank pressure PT is lower than the lower limit pressure Pf with the tank control valve 42 opened, it is possible to prevent the pressure accumulation tank 18 from being filled with compressed air from the compressor 16 by closing the pilot valve 44. .

  Therefore, even when the closing of the tank control valve 42 is delayed when the pressure accumulating tank 18 is in an insufficient pressure state, the pilot valve 44 is closed and the compressed air from the compressor 16 is sent to the air springs 12 to 15. Supplied with priority.

  FIG. 2 is a diagram schematically showing a data map 52 representing the relationship between tank pressure and vehicle height difference, and is created based on data measured in advance through experiments. In the data map 52, the vertical axis represents the tank pressure P, and the horizontal axis represents the vehicle height difference ΔH between the target vehicle height and the actual vehicle height, and a plurality of data maps 52 are based on the relative relationship between the tank pressure and the vehicle height difference. Compressor use areas A to F. Regions A to E are regions where the tank pressure PT is the lower limit pressure Pf to the upper limit pressure Pmax and the vehicle height difference is 0 to −30 mm. A region F indicates a region where the tank pressure is less than the lower limit pressure Pf and the tank pressure is insufficient to perform the vehicle height raising control.

  In addition, the areas A to F are defined by setting the virtual boundary lines I to IV in which the vehicle height differences are −5 mm, −10 mm, −15 mm, and −20 mm when the tank pressure PT = Pf. F is decided. FIG. 2 shows an example of the division of the areas A to F. For example, each area may be further subdivided by increasing the virtual boundary line. In FIG. 2, the vehicle height difference is shown as 0 to −30 mm. However, the adjustment range varies depending on the vehicle type, so the maximum difference is not always −30 mm.

  Here, the vehicle height raising control process executed by the control unit 24 will be described with reference to the flowchart of FIG. When the vehicle height raising control command is input, the control unit 24 reads the actual vehicle height Hv measured by the vehicle height sensor 22 in S10 shown in FIG. Subsequently, in S11, a vehicle height difference ΔH obtained by subtracting the actual vehicle height Hv from the preset target vehicle height Ho is calculated (calculation means).

  In next S12, the tank pressure PT measured by the pressure sensor 20 is read. At this time, since the compressor 16 is not driven and the compressed air in the pressure accumulating tank 18 is supplied to the air springs 12 to 15, the pressure sensor 20 detects the tank pressure PT.

  In the next S13, the threshold value obtained from the vehicle height difference and the tank pressure measured this time by comparing the measured values of the vehicle height difference and the tank pressure with the data map 52 shown in FIG. (Region determination means).

  Subsequently, the process proceeds to S14 to check whether or not the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region A (adjustment range setting means). In S14, if the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region A, the tank control valve 42 is opened because the tank pressure for the vehicle height difference is sufficient. The compressed air in the pressure accumulation tank 18 is continuously supplied to the air springs 12 to 15 until the actual vehicle height reaches the target vehicle height. Therefore, when the determination result is the region A, the vehicle height can be adjusted only by the pressure of the pressure accumulation tank 18 without using the compressor 16.

  In S14, when the determination result is other than the region A, the process proceeds to S16, and it is checked whether or not the determination result based on the current measurement condition (vehicle height difference and tank pressure) is included in the region B. In S16, when the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region B, the compressed air in the pressure accumulation tank 18 is supplied to the air springs 12 to 12 until the vehicle height difference becomes -5 mm. Continue to supply to 15. In this case, the vehicle height adjustment range by the compressed air from the pressure accumulation tank 18 is set to a vehicle height difference of -5 mm or less by the adjustment range setting means.

  When the vehicle height difference becomes -5 mm, the tank control valve 42 of the pressure accumulating tank 18 is closed, and the compressor 16 is driven to supply the compressed air generated by the compressor 16 to the air springs 12 to 15. Supply. Therefore, the vehicle height adjustment is performed only by the pressure from the compressor 16 until the vehicle height difference reaches -5 mm to the target vehicle height (vehicle height difference = 0).

  In S16, if the determination result is other than the region B, the process proceeds to S18, and it is checked whether or not the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region C. In S18, when the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region C, the compressed air in the pressure accumulating tank 18 is supplied to the air springs 12 to 12 until the vehicle height difference becomes -10 mm. Continue to supply to 15. In this case, the vehicle height adjustment range by the compressed air from the pressure accumulation tank 18 is set to a vehicle height difference of −10 mm or less by the adjustment range setting means.

  When the vehicle height difference becomes -10 mm, the tank control valve 42 of the pressure accumulating tank 18 is closed, and the compressor 16 is driven to supply the compressed air generated by the compressor 16 to the air springs 12 to 15. Supply. Therefore, the vehicle height adjustment is performed only by the pressure from the compressor 16 until the vehicle height difference reaches -10 mm to the target vehicle height (vehicle height difference = 0).

  In S18, when the determination result is other than the region C, the process proceeds to S20, and it is checked whether or not the determination result based on the current measurement condition (vehicle height difference and tank pressure) is included in the region D. In S20, when the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region D, the compressed air in the pressure accumulating tank 18 is supplied to the air springs 12 to 12 until the vehicle height difference becomes -15 mm. Continue to supply to 15. In this case, the vehicle height adjustment range by the compressed air from the pressure accumulation tank 18 is set to a vehicle height difference of −15 mm or less by the adjustment range setting means.

  When the vehicle height difference becomes -15 mm, the tank control valve 42 of the pressure accumulating tank 18 is closed, and the compressor 16 is driven to supply the compressed air generated by the compressor 16 to the air springs 12 to 15. Supply. Therefore, the vehicle height adjustment is performed only by the pressure from the compressor 16 until the vehicle height difference reaches -15 mm to the target vehicle height (vehicle height difference = 0).

  If the determination result is other than the region D in S20, the process proceeds to S22, and it is checked whether or not the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region E. In S22, when the determination result based on the current measurement condition (vehicle height difference and tank pressure) is included in the region E, the compressed air in the pressure accumulation tank 18 is supplied to the air springs 12 to 12 until the vehicle height difference becomes -20 mm. Continue to supply to 15. In this case, the vehicle height adjustment range by the compressed air from the pressure accumulation tank 18 is set to a vehicle height difference of −20 mm or less by the adjustment range setting means.

  When the vehicle height difference becomes -20 mm, the tank control valve 42 of the pressure accumulating tank 18 is closed, and the compressor 16 is driven to supply the compressed air generated by the compressor 16 to the air springs 12 to 15. Supply. Therefore, the vehicle height adjustment is performed only by the pressure from the compressor 16 until the vehicle height difference reaches −20 mm from the target vehicle height (vehicle height difference = 0).

  In S22, if the determination result is other than the region E, the process proceeds to S24, and it is determined that the determination result based on the current measurement conditions (vehicle height difference and tank pressure) is included in the region F. The tank control valve 42 of the pressure accumulation tank 18 is closed regardless of the vehicle height difference, and the compressor 16 is driven to supply the compressed air generated by the compressor 16 to the air springs 12 to 15. Therefore, when the determination result is included in the region F, since the tank pressure is equal to or lower than the lower limit pressure Pf, only the pressure from the compressor 16 is used until the vehicle height difference reaches the target vehicle height (vehicle height difference = 0). The vehicle height is adjusted.

  Thus, the threshold value (region) of the vehicle height raising control is determined by comparing the measurement condition (vehicle height difference and tank pressure) with the data map 52 to determine in which region of the regions A to F the measurement condition is included. The compressed air supply source that supplies the compressed air to the air springs 12 to 15 with the vehicle height difference corresponding to each region can be switched from the accumulator tank 18 to the compressor 16. As a result, switching from the accumulator tank 18 to the compressor 16 can be performed at an optimal timing, and vehicle height adjustment control can be performed with higher accuracy. Therefore, it becomes possible to eliminate the delay in the vehicle height adjustment speed due to the insufficient pressure of the pressure accumulating tank, which has been a conventional problem.

  For example, when the pressure in the pressure accumulating tank 18 is insufficient with respect to the vehicle height difference (less than the lower limit pressure Pf), the vehicle height can be adjusted by increasing the vehicle height adjustment range only by the compressor 16 as in regions E and F. It becomes possible to prevent the adjustment from being delayed. When the pressure in the pressure accumulating tank 18 is sufficiently high, for example, high pressure compressed air is supplied from the pressure accumulating tank 18 to each of the air springs 12 to 15 as in the areas A and B, so that the vehicle height adjustment is responsive. It becomes possible to increase.

  In addition, when the adjustment range of the vehicle height difference is -5 mm to -20 mm, but the tank pressure changes in the vicinity of the intermediate value between the lower limit pressure Pf and the upper limit pressure Pmax, for example, the regions B to E By limiting the vehicle height adjustment range (−5 mm, −10 mm, −15 mm, −20 mm) using only the pressure accumulation tank 18 as described above, it becomes possible to prevent the vehicle height adjustment from being delayed.

  FIG. 4 is a system diagram showing a modification of the vehicle height adjusting device. 4, the same parts as those in FIG. 1 described above are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 4, the pressure accumulation path 46 communicates directly with the pressure accumulation tank 18 instead of the pilot valve 44. Therefore, the pressure accumulation tank 18 is connected in parallel with the branch system path 40 as the first system path and the pressure accumulation system path 46 as the second system path. Therefore, when the tank pressure accumulation control valve 48 is opened according to an instruction from the control unit 24, the pressure accumulation tank 18 is filled with the compressed air generated by the compressor 16 via the branch line 40 and another pressure accumulation line 46. Can do.

  Therefore, in the system of this modified example, compressed air can be supplied to the pressure accumulation tank 18 without going through the tank control valve 42 and the pilot valve 44. Therefore, since the pressure accumulation path 46 does not merge with the branch path 40 and is an independent path, the time required for filling the pressure accumulation tank 18 with air can be shortened.

  Also in this modified example, when the tank pressure PT falls below the lower limit pressure Pf with the tank control valve 42 opened, the compressed air from the compressor 16 is supplied to the pressure accumulation tank 18 by closing the pilot valve 44. Filling can be prevented.

1 is a system diagram showing an embodiment of a vehicle height adjusting device according to the present invention. It is the figure which showed typically the data map 52 showing the relationship between a tank pressure and a vehicle height difference. 4 is a flowchart for explaining a vehicle height raising control process executed by a control unit 24; It is a system system | strain diagram which shows the modification of a vehicle height adjustment apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle height adjustment apparatus 12-15 Air spring 16 Compressor 18 Accumulation tank 20 Pressure sensor 22 Vehicle height sensor 24 Control part 30 Air supply system path 32-35 Vehicle height adjustment valve 40 Branch system path 42 Tank control valve 44 Pilot valve 48 Tank Accumulation control valve 50 Memory 52 Data map

Claims (4)

A compressor mounted on the vehicle,
An accumulator tank for accumulating compressed air compressed by the compressor;
An air spring that is supplied with compressed air to adjust the vehicle height;
A vehicle height sensor for detecting a vehicle height of the vehicle;
A pressure sensor for detecting the pressure of the compressed air supplied to the air spring;
A calculation means for calculating a vehicle height difference obtained by subtracting an actual vehicle height detected by the vehicle height sensor from a preset target vehicle height;
An air supply source that supplies compressed air to the air spring based on a threshold value obtained from a correspondence relationship between the vehicle height difference calculated by the calculating means and the pressure detected by the pressure sensor is supplied from the pressure accumulation tank to the compressor. Air supply source switching means for switching;
A vehicle height adjusting device comprising: The air supply source switching means is
Storage means for storing a data map representing the vehicle height difference with respect to the pressure of the accumulator tank in a plurality of regions;
A region determination unit that determines which region includes a threshold value obtained from the relationship between the pressure detected by the pressure sensor and the vehicle height difference in comparison with the data map stored in the storage unit;
An adjustment range setting means for setting a vehicle height adjustment range by compressed air from the pressure accumulating tank according to the area determined by the determination means;
The compressed air from the pressure accumulation tank is supplied to the air spring until the vehicle height adjustment range set by the adjustment range setting means is adjusted, and when the adjustment of the vehicle height adjustment range is completed, the compression from the compressor Vehicle height adjusting means for switching the air supply path so as to supply air to the air spring;
The vehicle height adjusting device according to claim 1, comprising: The vehicle height adjusting means is
A tank control valve provided in a system communicating with the accumulator tank;
When the pressure of the pressure accumulating tank is provided in the system and the pressure of the pressure accumulating tank is equal to or higher than a predetermined value, the compressed air of the pressure accumulating tank is supplied to the air spring, and the pressure of the compressed air supplied from the pressure accumulating tank is predetermined. A pilot valve that closes and shuts off the system when it drops below a value;
An accumulator control valve for supplying compressed air from the compressor to the accumulator tank via the pilot valve and the tank control valve;
Until the vehicle height adjustment range set by the adjustment range setting means is adjusted, the tank control valve is opened to supply the compressed air from the accumulator tank to the air spring, and the vehicle height by the vehicle height adjustment means Control means for opening the pressure accumulation control valve when adjustment is completed and supplying compressed air from the compressor to the pressure accumulation tank;
The vehicle height adjusting device according to claim 2, comprising: The vehicle height adjusting means is
A tank control valve provided in a first system path communicated with the pressure accumulation tank;
Provided in the first system path, and opens when the pressure in the pressure accumulating tank is equal to or higher than a predetermined value, and supplies the compressed air from the pressure accumulating tank to the air spring, and the compressed air supplied from the pressure accumulating tank A pilot valve that closes and shuts off the first system when the pressure drops below a predetermined value; and
An accumulator control valve provided in a second system path communicating with the accumulator tank, and supplying compressed air from the compressor to the accumulator tank;
Until the vehicle height adjustment range set by the adjustment range setting means is adjusted, the tank control valve is opened to supply the compressed air from the accumulator tank to the air spring, and the vehicle height by the vehicle height adjustment means is adjusted. Control means for opening the pressure accumulation control valve when adjustment is completed and supplying compressed air from the compressor to the pressure accumulation tank;
The vehicle height adjusting device according to claim 2, wherein

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