JP3065206B2 - Air suspension compressed air supply / discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air suspension for a vehicle such as an automobile, and more particularly to a compressed air supply / discharge device for an air suspension.

[0002]

2. Description of the Related Art An air suspension for a vehicle such as an automobile generally includes an air spring provided for each wheel and a compressed air supply / discharge device for supplying / discharging compressed air to / from the air spring. ing. As one of the compressed air supply / discharge devices for such an air suspension, for example, as described in JP-A-4-365613, a low-pressure tank and a high-pressure tank for storing compressed air, and a device for compressing air supplied from the atmosphere. A low pressure tank or a compressor which further compresses the compressed air in the low pressure tank and supplies it to the high pressure tank, and a dryer disposed between the low pressure tank and the compressor, whereby the compressor has a pressure lower than the atmospheric pressure. BACKGROUND ART A compressed air supply / discharge device for an air suspension configured to dry air supplied to a tank is conventionally known.

According to such a compressed air supply / discharge device, the air supplied from the atmosphere is dried by the dryer when it is supplied to the low pressure tank, so that the compressed air circulated in the air suspension is always dried. In this state, the moisture contained in the compressed air is condensed, which can reduce the possibility of rusting, deterioration of rubber parts, etc. in air suspension conduits and control valves, and freezing of water. This can reduce the possibility that the control valve or the like may malfunction.

[0004]

However, in the above-mentioned conventional compressed air supply / discharge system for an air suspension, the compressor is a high-speed rotary type compressor driven by an engine. If the lubricating oil needs to be circulated, a part of the compressed air leaks out of the compressor together with the lubricating oil, so air must be replenished relatively frequently from the atmosphere. A dryer using a desiccant such as silica gel for drying the supplied air is essential.

In addition to the first switching valve for switching the connection state on the suction side of the compressor between the low pressure tank and the atmosphere, the second switching valve for switching the connection state on the discharge side between the high pressure tank or the dryer and the low pressure tank. Is required, and therefore the number of components of the compressed air supply / discharge device is large, and the structure and control of the compressed air supply / discharge device tend to be complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the conventional compressed air supply / discharge device for an air suspension, and an object of the present invention is to reduce the leakage of compressed air in a compressor. By reducing the required amount of air replenishment, the air suspension is improved so that a desiccant type dryer that has high ventilation resistance and requires regeneration treatment is not required and the number of switching valves can be reduced. It is to provide a compressed air supply / discharge device.

[0007]

According to the present invention, there is provided an exhaust passage and an air supply passage connected to an air spring provided for each wheel, and an exhaust passage connected to the exhaust passage. A low-pressure tank, a high-pressure tank connected to the air supply passage, a compressor driven by an engine to selectively supply air in the low-pressure tank to the high-pressure tank, and a pressure in the low-pressure tank being equal to or less than a predetermined value. The air supply means for supplying the atmosphere into the low-pressure tank in response thereto, and a lubrication means for lubricating the compressor with lubricating oil, wherein the compressor and the lubrication means are housed in a closed container. This is achieved by a compressed air supply / discharge device for an air suspension.

[0008]

According to the above construction, the compressor and the lubricating means are housed in a closed container, and the compressor is lubricated with the lubricating oil by the lubricating means, so that a part of the compressed air and the lubricating oil are discharged from the compressor. Leaked to
Since the air does not leak out of the closed container, the amount and frequency of air replenishment from the atmosphere is greatly reduced as compared with the conventional case, and thus a desiccant type for drying the air replenished from the atmosphere. Eliminates the need for a dryer. Since a dryer is not required, a switching valve for switching between a mode in which air is supplied from the atmosphere to the low-pressure tank via the dryer and a mode in which air in the low-pressure tank is supplied to the high-pressure tank is not required.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 1 is a schematic diagram showing a first embodiment of a compressed air supply / discharge device for an air suspension according to the present invention.

In FIG. 1, reference numeral 10 denotes a shock absorber 1.
2 shows an air spring provided integrally with the air spring 2, and an air spring 10 cooperates with a shock absorber to define an air chamber 14 therein. Also, in FIG.
Reference numeral 16 denotes a low-pressure tank that stores compressed air therein, reference numeral 18 denotes a high-pressure tank that stores compressed air at a pressure higher than that of the low-pressure tank, and reference numeral 20 denotes a compressor.

In the illustrated embodiment, the compressor 20
Is a variable displacement compressor driven by an engine (not shown). As will be described in detail later, a hydrophilic lubricating oil stored in an oil reservoir 24 is also driven by an oil pump 26 and an oil pump. The sliding portion of the compressor is lubricated by being supplied through the lubricating oil circulation passage 28, and the compressor 20, the oil reservoir 24, the oil pump 26 and the lubricating oil circulation passage 28 are housed in a closed container 30. Have been.

An inlet of the compressor 20 is connected to one end of an air supply conduit 34 having a switching valve 32 on the way, and the other end of the supply conduit 34 is connected to the low-pressure tank 16. One end of an air supply conduit 36 is connected to the switching valve 32, and a filter 38 is provided at the other end of the air supply conduit 36, and the filter 38 is opened to the atmosphere at the filter. In the middle of the atmosphere supply conduit 36, a switching valve 32 is provided by a filter 38.
A non-return valve 37 is provided to allow only the flow of air toward the outlet. The switching valve 32 is in a first position (normal position) where the supply conduit 34 is kept in communication with the electronic control unit as described later.
And the supply conduit 34 is switched to a second position connecting the air supply conduit 36, whereby the suction port of the compressor 20 is selectively connected to the low pressure tank 16 or the atmosphere by the switching valve 32. .

One end of an air supply conduit 40 is connected to the discharge port of the compressor 20, and the other end of the supply conduit 40 is connected to the other end of an air supply / discharge conduit 42 connected to the air chamber 14 of the air spring 10 at one end. Connected to the end. In the middle of the air supply conduit 40, a cooling device 44 for cooling air flowing in the conduit, a mist separator 46 for separating and removing liquid components such as moisture and lubricating oil from the air flowing in the conduit 40, and air from the compressor 20 A check valve 48 that allows only the flow of the compressed air flowing toward the chamber 14 and a supply control valve 50 that controls the supply of the compressed air to the air chamber 14 are provided.

The cooling device 44 is provided, for example, in such a manner that a portion of the supply conduit 40 close to the compressor 20 is disposed near a front grill of a vehicle (not shown) or behind a bumper, so that air flowing inside the supply conduit 40 is provided. May be configured to be cooled by the traveling wind. Further, the mist separator 46 may have a structure utilizing a centrifugal separation function as described in the specification and drawings of Japanese Patent Application No. 5-91967 filed by the present applicant. The mist separator 46 is connected to the oil reservoir 24 by a return conduit 54 having a check valve 52 in the middle, so that the liquid component separated by the mist separator is returned to the oil reservoir.

The other end of the air supply / discharge conduit 42 is connected to one end of an air discharge conduit 58 having a discharge control valve 56 on the way, and the other end of the discharge conduit 58 is connected to the low pressure tank 16. The high-pressure tank 18 is connected to the air supply conduit 40 between the check valve 48 and the supply control valve 50. The supply control valve 50 and the discharge control valve 56 are normally-closed on-off valves controlled by an electronic control unit as described later, so that the compressed air discharged from the high-pressure tank 18 or the compressed air discharged from the compressor 20 can be used as necessary. The air is supplied to the air chamber 14 through the supply control valve 50, and the high-pressure air in the air chamber is returned to the low-pressure tank 16 through the discharge control valve 56.

Although not shown in FIG. 1, the air supply conduit 40 and the air discharge conduit 58 are each branched for each wheel, and the air spring 10, the shock absorber 12, the air supply / discharge conduit 42, and the control valve are provided. 50 and 56 are provided corresponding to each wheel.

FIG. 2 is an enlarged vertical sectional view showing one embodiment of the compressor and the oil pump shown in FIG. 1 which is configured as an oil pump built-in type swash plate type compressor. In FIG. 2, members corresponding to those shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

In FIG. 2, reference numerals 60 and 62 denote a main housing and a sub-housing of the compressor 20, respectively. End housings 64 and 66 are fixed to the main housing 60 and the sub-housing 62, respectively. The main housing 60 and the end housing 64 cooperate with each other to support the control spool 68 so as to be able to reciprocate along the axis 70.
The end housing 66 cooperates with each other to rotatably support the main shaft 72 about the axis 70.

Although not shown in FIG. 2, a pulley is fixed to the outer end (left end in FIG. 2) of the main shaft 72 so that the driving force from the engine is input via a belt. Has become. The inner end of the main shaft 72 (FIG. 2)
A hollow shaft 74 is fitted on the right end of the main housing 60 so as to be able to reciprocate along the axis 70 relatively thereto. It is supported rotatably. A compression coil spring 76 is elastically mounted between opposing shoulders of the main shaft 72 and the hollow shaft 74, and a compression coil spring 78 is elastically mounted between the control spool 68 and the inner wall surface of the end housing 64. Have been.

A swash plate 82 is disposed in an internal space 80 defined by the main housing 60 and the sub-housing 62 in a state of being loosely fitted to a hollow shaft 74. A pair of pivots 8 extending perpendicular to the axis 70 on the near side and the far side as viewed in FIG.
4 pivotally supported by the hollow shaft 74. The swash plate 82 also has a pair of brackets 86 that extend to the left with respect to the main shaft 72 on the front side and the rear side as viewed in FIG. 2, and these brackets extend parallel to the pivot 84. Both ends of the existing pin 88 are fixed. Pin 88 is located at the center of main shaft 72 at axis 70.
Are inserted in a substantially elliptical groove 90 provided so as to be able to reciprocate along the groove.

Although only one of each is shown in FIG. 2, the main housing 60 and the sub-housing 62 extend along the axis 70 at positions spaced apart from each other around the axis 70. Cylinder bore member 92
And 94 are fixed by press fitting. The corresponding cylinder bore members 92 and 94 extend along a common axis 96 that is parallel to the axis 70, and these cylinder bore members 92 and 94 are provided with opposite body portions 98A and 98B of a piston 98. It fits reciprocally along 96. Substantially spherical recesses are provided in the center opposite end surfaces of the rod portion 98C of the piston 98, and these recesses have substantially hemispherical shoes 100.
And 102 are arranged, and a swash plate 8 is interposed between these shoes.
The outer peripheral thin portions 2 are fitted around these around the axis 70 so as to be relatively displaceable.

Valve seat elements 104 and 106 are disposed between the main housing 60 and the end housing 64 and between the sub-housing 62 and the end housing 66, respectively. Disposed valve elements 108 and 110 are arranged on the side, with pistons 98 against valve seat elements 104 and 106.
Are arranged suction valve elements 112 and 114. These valve seat elements and valve elements cooperate with cylinder bore members 92, 94 and body portions 98A, 98B to define cylinder chambers 116 and 118, respectively, and cooperate with end housings 64 and 66, respectively. Inlet plenums 120, 122 and exhaust plenums 124, 126 are defined.

Control spool 68 and end housing 64
A control chamber 128 is defined between the control chamber 128 and the inner wall of the control chamber 128. Although not shown in detail in FIG. 2, the pressure in the control chamber 128 is controlled by the pressure in the intake plenum 120 and the pressure in the exhaust plenum 124. It is controlled by the pressure control valve 130 on the basis of the pressure. The pressure control valve 130 is controlled by an electronic control unit as described later, thereby controlling the inclination angle of the swash plate 82,
Accordingly, the discharge flow rate of the compressor 20 is increased or decreased by increasing or decreasing the pressure in the control chamber 128 according to a control signal from the electronic control unit.

For example, when the pressure in the control chamber 128 is increased, the control spool 68 is driven to the left as viewed in FIG. 2, and the hollow shaft 74 is driven to the left by the control spool 68 via the thrust bearing 132. , The swash plate 82 is driven to the left by the pivot 84, and the pin 88 is moved toward the end housing 66 in the groove 90, whereby the swash plate 8 is moved.
2 is increased, the reciprocating distance of the piston 98 for each rotation of the main shaft 72 is increased, and the discharge flow rate of the compressor 20 is increased.

Conversely, when the pressure in the control chamber 128 is reduced, the control spool 68 is driven rightward in FIG. 2 and the hollow shaft 74 is moved rightward by the control spool 68 by the spring force of the compression coil spring 76. The swash plate 82 is driven to the right by the pivot 84, and the pin 88 is moved to the side of the hollow shaft 74 in the groove 90, whereby the inclination angle of the swash plate 82 is reduced and the main shaft 72 is The reciprocating distance of the piston 98 per revolution is reduced, and the compressor 20
Is reduced.

Further, in the illustrated embodiment, the oil pump 26 is provided in the end housing 66. The oil pump 26 is a trochoid type rotary pump known per se, and has a drive rotor 134 and a driven rotor 136 which are fixed to the main shaft 72 and rotate around the axis 70 together therewith. 2, a suction plenum 138 and a discharge plenum 140 are defined on the left and right sides, respectively, as viewed in FIG.

The suction plenum 138 is provided in the main housing 6.
The oil reservoir 24 defined by the sub-housing 62 and the end housing 66 is connected to the oil reservoir 24 by a supply passage 142, and the oil reservoir 24 is connected to the internal space 80 by a passage (not shown). . On the other hand, one end of an internal passage 144 provided in the main shaft 72 communicates with the discharge plenum 140, and the internal passage 144 extends to the inner end surface of the main shaft 72. Further, the internal passage 144 is provided with a connecting shaft 14 provided in the pivot 84 for pivotally supporting the swash plate 82 and the hollow shaft 74.
6 is in communication with an internal passage 148 provided in the swash plate 82. The internal passage 148 is open on both sides of the thin portion between the thick portion of the swash plate and the thin portion around the swash plate at a plurality of positions spaced apart from each other around the center of the swash plate.

Thus, the oil pump 26 pumps up the lubricating oil in the oil reservoir 24, and pumps it up to the compressor 20.
Is circulated to each of the sliding portions. Supply passage 142, internal passage 144, connection passage 146, internal passage 1
48, the internal space 80 and the like constitute the lubricating oil circulation passage 28 shown in FIG. 1, and the main housing 60, the sub-housing 62, and the end housings 64 and 66 include the oil pump 26 as the lubricating means, the oil reservoir 24, and The closed container 30 shown in FIG. 1 that accommodates the lubricating oil circulation passage (28) is defined.

As shown in FIG. 3, in the first embodiment shown, the pressure control valve 130 of the compressor 20
The switching valve 32, the supply control valve 50, and the discharge control valve 56 include a pressure sensor 160 for detecting the pressure PL in the low-pressure tank 16 and a pressure sensor 16 for detecting the pressure PH in the high-pressure tank 18.
2. a signal from a pressure sensor 164 * for detecting the pressure P * (* is a symbol corresponding to each wheel) in the air chamber 14 of each air spring 10, and a vehicle speed sensor for detecting a vehicle speed;
A group of sensors 166 such as a lateral acceleration sensor for detecting the lateral acceleration of the vehicle body, a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle body, and a vehicle height sensor for detecting the vehicle height of a portion corresponding to each wheel.
Based on this signal, the electronic control unit 168 is controlled as described later.

The electronic control unit 168 has a microcomputer 170 as shown in FIG. The microcomputer 170 may have a general configuration as shown in FIG.
174, RAM 176, input port device 180,
And an output port device 182, which are connected to each other by a bidirectional common bus 184. A signal indicating the pressure PL in the low-pressure tank 16 detected by the pressure sensor 160 is provided to the input port device 180.
2, a signal indicating the pressure PH in the high-pressure tank 18 detected by the pressure sensor 2, a signal indicating the pressure P * in each air chamber 14 detected by the pressure sensor 164 *, and a vehicle detected by a group of sensors 166 such as a vehicle speed sensor. Is input.

The input port device 180 appropriately processes the signal input thereto, and outputs the processed signal to the CPU and the RAM 176 in accordance with an instruction of the CPU 172 based on a program stored in the ROM 174. The ROM 174 stores the control program shown in FIG. The CPU 172 performs various calculations and signal processing based on the control program shown in FIG. The output port device 182 is the CPU 1
72, control signals are output to the switching valve 32 and the pressure control valve 130 via the drive circuits 186 and 188, respectively, and the supply control valve 50 * and the discharge control valve 56 * via the drive circuits 190 * and 192 *, respectively. The control signal is output to the

Next, the operation of the compressed air supply / discharge device in the illustrated embodiment will be described with reference to the flowchart shown in FIG. The routine shown in FIG. 4 is started by closing an ignition switch (not shown).

In step 10, the detection result detected by each sensor is read. In step 20, it is determined whether the pressure PH in the high-pressure tank 18 is less than the first upper limit value PHHL. When the determination is made and the negative determination is made, the process proceeds to step 60, and when the affirmative determination is made, the process proceeds to step 30. In step 30, it is determined whether or not the pressure PL in the low-pressure tank 16 is less than the lower limit value PLL. If an affirmative determination is made, step 40 is executed.
When the compressed air supply / discharge device is operated in the air supply mode in step S5, and a negative determination is made, the compressed air supply / discharge device is operated in the two-stage compression mode in step S50.

In the air supply mode, when the switching valve 32 is switched to the second position, the air supply conduit 34 is turned on.
Is connected to the atmosphere supply conduit 36, the compressor 20 is operated, and the control valves 50 and 56 are alternately opened, whereby the air in the atmosphere is filtered by the filter 38 and the conduit 3
6, 34, 40, 42, the air chamber 14, and the conduit 58 are supplied to the low pressure tank 16. Further, in the two-stage compression mode, the switching valve 32 is switched to the first position, whereby the air supply conduit 34 is connected to the low-pressure tank 16 and the compressor 20 is operated, whereby the air in the low-pressure tank is released. It is fed via conduits 34 and 40 to the high pressure tank. In any of these modes, the compressed air discharged from the compressor 20 is cooled by the cooling device 44 so that the liquid component in the compressed air is condensed to some extent, and then the mist separator 46 separates the liquid component. Since the compressed air is removed, the compressed air is efficiently dried without high pressure loss.

In step 60, the pressure PH in the high-pressure tank is higher than the first upper limit PHHL and the second upper limit P
It is determined whether the pressure is lower than HHH (> PHHL). If a negative determination is made, the routine proceeds to step 80, and if an affirmative determination is made, at step 70 the inclination angle of the swash plate 82 of the compressor 20 is determined. Is set to 0, the discharge flow rate of the compressor is set to 0, whereby the supply of compressed air from the low-pressure tank 16 to the high-pressure tank 18 is stopped.

In step 80, it is determined whether or not the pressure PH in the high-pressure tank exceeds a second upper limit value PHHH. If a negative determination is made, the process directly returns to step 10 and an affirmative determination is made. Step 90 if performed
At this time, the discharge flow rate of the compressor 20 is set to 0, and the control valves 50 and 56 are respectively opened for a predetermined time.
As a result, the compressed air in the high pressure tank 18 is removed from the low pressure tank 1 without greatly changing the pressure in the air chamber 14.
It is discharged into 6.

FIG. 5 is a schematic structural view showing a second embodiment of a compressed air supply / discharge device for an air suspension according to the present invention. In FIG. 5, members corresponding to those shown in FIG. 1 are denoted by the same reference numerals as in FIG.

In this embodiment, the switching valve 32 is not provided in the middle of the air supply conduit 34, and the supply conduit 34
Is directly connected to the low-pressure tank 16. One end of the air supply conduit 36 is also connected to the low-pressure tank 16, and an air supply compressor 194 is provided between the check valve 37 and the filter 38 in the middle of the air supply conduit 36. The air supply compressor 194 is selectively driven by an electric motor, not shown in FIG. 5, but controlled by an electronic control unit, whereby air in the atmosphere is directly supplied to the low-pressure tank 16. .

This embodiment is otherwise the same as the first embodiment, so that the compressor 20
The air supply compressor 194 and the control valves 50 and 56 are controlled by an electronic control device similar to the electronic control device 168 according to a control flow similar to the control flow shown in FIG. However, in this case, the atmospheric supply compressor 194 is normally kept stopped, and is operated for a predetermined time in step 40 of the flowchart of FIG.

In each of the first and second embodiments, the pressure PL in the low pressure tank 16 is lower than the lower limit of the pressure fluctuation in the air chamber 14 of the air spring 10 by the compressed air supply / discharge device. Is also maintained at a low pressure and the high pressure tank 1
8, the pressure PH is maintained at a pressure higher than the upper limit of the pressure fluctuation in the air chamber, and in that state, the vehicle height control (body posture control) of each wheel is performed as follows.

That is, when the vehicle height of a specific wheel is increased in order to increase the vehicle height of the entire vehicle or to reduce the change in the posture of the vehicle body accompanying the traveling of the vehicle, the control valve 50 is opened. At the same time, the control valve 56 is maintained in a closed state, whereby high-pressure compressed air is supplied from the high-pressure tank 18 to the air chamber 14 of the air spring 10 through a part of the conduit 40 and the conduit 42, and the pressure in the air chamber is reduced. Is increased.

Conversely, when the vehicle height of a specific wheel is reduced in order to reduce the vehicle height of the entire vehicle or to reduce the change in the posture of the vehicle body accompanying the traveling of the vehicle, the control valve 56 is opened. At the same time, the control valve 50 is maintained in the closed state, whereby the compressed air in the air chamber 14 of the air spring 10 is discharged to the low-pressure tank 16 through the conduit 42 and a part of the conduit 58, whereby the air in the air spring 10 is discharged. The pressure is reduced.

As is clear from the above description, according to the illustrated embodiments, the compressor 20, the oil reservoir 24 as the lubricating means, the oil pump 26, and the lubricating oil circulation passage 28 are accommodated in the closed container 30. Therefore, even when the compressed air supply / discharge device is operated in any mode, it is possible to reliably prevent the compressed air leaking from the compressor from flowing out into the atmosphere by the closed container 30. Therefore, the amount of compressed air in the compressed air supply / discharge device that decreases over time can be greatly reduced, and the amount and frequency of supplying air from the atmosphere can be significantly reduced.

In particular, according to the first embodiment, since the air supplied from the atmosphere is always dried by the mist separator 46, the compressed air in a dry state can always be stored in the low-pressure tank 16. According to the second embodiment, the air supplied from the atmosphere is directly supplied to the low-pressure tank 16, so that the air can be supplied regardless of the operation states of the compressor 20 and the control valves 50 and 56.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments may be included within the scope of the present invention. It will be clear to those skilled in the art that is possible.

For example, in the air supply mode and the exhaust mode in the first embodiment, and in the exhaust mode in the second embodiment, the compressor 20 The compressed air to be discharged or the compressed air in the high-pressure tank 18 is supplied to the low-pressure tank 16 through the air chamber 14, and the check valve 48 and the supply control valve 50 of the air supply conduit 40 are connected to each other. Between the low pressure tank 16 of the air discharge conduit 58 and the discharge control valve 5
6 is provided so that compressed air is supplied to the low-pressure tank 16 through the bypass on-off valve without opening and closing the control valves 50 and 56. May be done.

[0048]

As is apparent from the above description, according to the present invention, the compressor and the lubricating means are housed in a closed container, and the compressed air is lubricated by the lubricating oil by the lubricating means. Even if a part of the air leaks out of the compressor together with the lubricating oil, the air can be reliably prevented from leaking out of the closed container. Can be greatly reduced, thereby eliminating the need for a desiccant type dryer for drying air supplied from the atmosphere, thereby avoiding pressure loss caused by the dryer, The need to operate the compressed air supply / discharge device in the regeneration mode to regenerate the desiccant can be eliminated.

Further, since a desiccant type dryer is not required, a mode for switching between a mode in which air is supplied from the atmosphere to the low-pressure tank via the dryer and a mode in which air in the low-pressure tank is supplied to the high-pressure tank is used. No switching valve is required, so the number of components of the compressed air supply / discharge device can be reduced as compared with the conventional case, the structure and control of the compressed air supply / discharge device can be simplified, and the compressor and the lubricating means can be sealed in a sealed container The compressed air supply / discharge device can be easily attached to the vehicle because it can be attached to the vehicle as one member housed therein.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a compressed air supply / discharge device for an air suspension according to the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing one embodiment of the compressor and the oil pump shown in FIG. 1 configured as an oil pump built-in type swash plate type compressor.

FIG. 3 is a block diagram showing one embodiment of an electronic control device for controlling the switching valve, the compressor, the supply control valve, and the discharge control valve shown in FIG. 1;

FIG. 4 is a flowchart showing a control routine of a compressed air supply / discharge device achieved by the electronic control device shown in FIG. 3;

FIG. 5 is a schematic configuration diagram showing a second embodiment of a compressed air supply / discharge device for an air suspension according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Air spring 16 ... Low pressure tank 18 ... High pressure tank 20 ... Compressor 26 ... Oil pump 30 ... Sealed container 32 ... Switching valve 50 ... Supply control valve 56 ... Discharge control valve 194 ... Atmospheric supply compressor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-47-44527 (JP, A) JP-A-4-365613 (JP, A) Fully open 58-112608 (JP, U) Really open 16911 (JP, U) Shokai Sho 57-181608 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60G 17/052

Claims (1)

(57) [Claims] An exhaust passage and an air supply passage connected to an air spring provided for each wheel, a low pressure tank connected to the exhaust passage, and a high pressure tank connected to the air supply passage. A compressor driven by an engine to selectively supply air in the low-pressure tank to the high-pressure tank, and to supply air to the low-pressure tank in response to the pressure in the low-pressure tank falling below a predetermined value. A compressed air supply / discharge device for an air suspension, comprising: an air supply unit; and a lubrication unit that lubricates the compressor with lubricating oil, wherein the compressor and the lubrication unit are housed in a closed container.