JPH06156041A - Compressed air intake and exhaust device - Google Patents

Abstract

PURPOSE:To eliminate a need of increasing operation voltage applied to a coil and increasing the number of turns of the coil, even when the pressure of the compressed air supplied to pneumatic equipment such as an air suspension is increased, and ensure electric power and space saving. CONSTITUTION:A stepped hole 38A is formed on the core 38 of an exhaust solenoid valve 30, and a pressure chamber 40 is formed between the large diameter side edge of a piston 39 slidably coupled to the hole 38A and a mounting cylinder 42. A part of the compressed air fed to the air chamber 8C of an air suspension 8 is introduced to the pressure chamber 40 as pilot pressure for pressure P1, and a valve spring 41 having a spring load (f) is laid between the piston 39 and the bottomed hole 35A of a plunger 35. Then, the plunger 35 is always pressed in a valve-close direction via the valve spring 41 under the pressing force (S1XP1) of the piston 39 having a pressure receiving area S1 for the pressure chamber 40. In this way, the pressure receiving area S2 of the valve section 36 relative to an inlet port 32B in the state where the valve section 36 of the plunger 35 is seated on a valve seat 32D, is made smaller than the pressure receiving area S1 of the piston 39.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed air supply / exhaust device which is suitable for use in, for example, a vehicle height adjusting device of a vehicle, and more particularly, to use an exhaust solenoid valve for exhausting compressed air from pneumatic equipment. The present invention relates to a compressed air supply / discharge device.

[0002]

2. Description of the Related Art FIG. 4 shows an example in which a compressed air supply / discharge device according to the prior art is used in a vehicle height adjusting device of an automobile.

In the figure, reference numeral 1 denotes a compressor driven by an electric motor 2. The compressor 1 is composed of, for example, a reciprocating compressor, and its suction side is connected to a suction filter 4 via a pipe line 3. The discharge side is connected to a dryer 6 described later via a pipe line 5. And the compressor 1
Is driven by the electric motor 2 to compress the outside air sucked from the suction filter 4 and discharge the compressed air into the conduit 5.

Reference numeral 6 denotes a dryer connected to the discharge side of the compressor 1 through a pipe 5. The dryer 6 contains a desiccant (not shown) such as silica gel and is discharged from the compressor 1. The moisture in the compressed air is adhered to the desiccant, and the compressed air in the dry state is supplied to the air suspension 8 described later through the air pipe 7. Also, the dryer 6
When compressed air is exhausted from the air suspension 8 through the air pipe 7 or the like by opening an exhaust solenoid valve 10 described later, the compressed air is circulated in the reverse direction toward the pipe line 5, and this exhausted air is exhausted. This desiccant is regenerated by desorbing the moisture adsorbed on the desiccant by utilizing the.

Reference numeral 8 denotes an air suspension (only one is shown) which is located on the front and rear wheels of the automobile and is provided between the axle side and the vehicle body side (neither is shown) as pneumatic equipment. , The air suspension 8 is a cylinder 8A
8C is formed between the piston rod 8B and the
The air chamber 8C is connected to the tip end side of the air pipe 7 via a joint 9. Compressed air is supplied to and discharged from the compressor 1 via the air pipe 7 into the air chamber 8C, and when the air chamber 8C expands and contracts, the piston rod 8B moves the vehicle body up and down. By adjusting the vehicle height, the vehicle height is adjusted.

Reference numeral 10 denotes an exhaust solenoid valve whose inflow side is connected in the middle of the pipeline 5 via the pipeline 11 and whose outflow side is connected to the suction filter 4 side via the pipeline 12. The exhaust solenoid valve 10 is The valve casing 13, a plunger 17, a valve spring 20, a coil 21, and the like, which will be described later, are roughly configured, and the valve spring 20 normally keeps the valve closed. The exhaust solenoid valve 10 is opened when power is supplied to the coil 21 from the outside, and the compressed air exhausted from the air suspension 8 through the air pipe 7, the dryer 6, the pipelines 5, 11 and the like. Is discharged from the suction filter 4 to the outside through the pipe line 12 and the like.

Reference numeral 13 denotes a valve casing of the exhaust solenoid valve 10. The valve casing 13 is formed in a stepped cylindrical shape and has a valve casing main body 14 closed at one end by a lid portion 14A and the valve casing at one end. The lid 14A side of the main body 14 is inserted, and the frame body 15 having a U-shaped cross section that covers the valve casing main body 14 from the outside together with the coil 21 and the other end side of the frame body 15 are attached to the valve casing main body 14
And an end cover 16 whose other end side is positioned in the frame body 15 via a core 19 described later. An inlet 14B is formed in the lid 14A of the valve casing body 14 in the axial direction and an outlet 14C in the radial direction.
Is formed, and the inflow port 14B and the outflow port 14C are
A communication path for communicating between 1 and 12 is configured. Also,
An inlet port 14B is provided in the lid portion 14A of the valve casing body 14.
A valve seat 14D is formed around the valve seat 14D, and a valve portion 18 of a plunger 17, which will be described later, is seated on the seat 14D.

Reference numeral 17 denotes a plunger slidably provided in the valve casing body 14. The plunger 17 is formed of a magnetic material such as iron into a substantially cylindrical shape, and one end side thereof is made of an elastic material such as rubber. The valve portion 18 is attached. Further, a bottomed hole 17A is formed in the other end side of the plunger 17 in the axial direction, and the valve spring 20 is provided in the bottomed hole 17A.
Is provided. The plunger 17 is constantly biased in the valve closing direction by the valve spring 20, and the valve portion 18 is seated on the valve seat 14D of the valve casing body 14 to open and close the inflow port 14B.

19 is located on the other end side of the plunger 17,
A core fixedly provided in the valve casing main body 14 is shown. The core 19 is formed of a magnetic material such as iron into a substantially columnar shape similar to the plunger 17, and the valve spring 20 when the coil 21 is excited. The plunger 17 is adsorbed against this. Further, a concave portion 19A is formed on one end side of the core 19 so as to face the bottomed hole 17A of the plunger 17, and the concave portion 1A is formed.
A valve spring 20 is disposed between 9A and the bottomed hole 17A of the plunger 17.

Reference numeral 21 denotes a coil as a solenoid, which is located outside the plunger 17 and the core 19 in the radial direction and is wound around the outer peripheral side of the valve casing main body 14.
1 is excited by energization from the outside, and the plunger 17 is attracted to the core 19 against the valve spring 20.
The plunger 17 is driven in the valve opening direction. Then, at this time, the valve portion 18 of the plunger 17 has the valve casing body 1
4 is separated from the valve seat 14D and the inlet 14B is connected to the outlet 14
Connect to C.

The vehicle height adjusting device according to the prior art has the above-mentioned structure, and its operation will be described below.

First, when compressed air is supplied to the air suspension 8, the compressor 1 is driven by the electric motor 2 with the exhaust solenoid valve 10 closed, and the compressed air discharged from the compressor 1 is driven. Through line 5 to dryer 6
Pump it in. Then, the compressed air is supplied to the air chamber 8C of the air suspension 8 through the air pipe 7 while being dried by the desiccant in the dryer 6, whereby the air suspension 8 is extended and the vehicle height of the automobile is increased. Then, when the desired height is reached, the electric motor 2 is stopped,
The supply of compressed air by the compressor 1 is stopped.

Next, when the compressed air is exhausted from the air suspension 8, the coil 21 of the exhaust solenoid valve 10 is used.
When the coil 21 is excited by energizing the
Is adsorbed to the core 19 against the valve spring 20, and at this time, the valve portion 18 of the plunger 17 is separated from the valve seat 14D of the valve casing main body 14 so that the inflow port 14B communicates with the outflow port 14C. Then, the compressed air in the air chamber 8C of the air suspension 8 flows into the dryer 6 through the air pipe 7, and while the moisture is desorbed from the desiccant in the dryer 6, the flow of the exhaust solenoid valve 10 from the pipe line 11 flows. The air is exhausted from the suction filter 4 to the outside through the inlet 14B, the outlet 14C, the pipe 12, and the like.

As a result, the air suspension 8 contracts to reduce the vehicle height of the automobile, and when the vehicle height reaches a desired height, the coil 21 is de-energized to close the exhaust solenoid valve 10. Exhaust of compressed air from the air suspension 8 is stopped.

When the compressed air is being discharged from the compressor 1, for example, when the air pipe 7 or the like is twisted or bent and an excessive pressure is generated in the pipe line 5, the excessive pressure at this time is generated. Acts on the valve portion 18 of the plunger 17 via the inflow port 14B of the exhaust solenoid valve 10, so that the valve portion 18 opens against the valve spring 20 and the excess pressure at this time is relieved to the outside.

[0016]

In the prior art described above, the exhaust solenoid valve 10 is constructed as a normally closed type exhaust valve, and the relief pressure is set by the spring load of the valve spring 20. 8 air chambers 8
In order to increase the pressure of the compressed air supplied into C, the spring load of the valve spring 20 needs to be set high. When the spring load of the valve spring 20 is set high,
Plunger 17 for opening the exhaust solenoid valve 10
When adhering to the core 19 against the valve spring 20, a large magnetic force must be generated by the coil 21.

For this reason, in the prior art, it is necessary to increase the operating voltage applied to the coil 21 or increase the number of turns of the coil 21, which leads to an increase in size as a whole, which leads to power saving and space saving. There is a problem that you can not do it.

The present invention has been made in view of the above-mentioned problems of the prior art. Even when the pressure of compressed air supplied to a pneumatic device such as an air suspension is increased, the present invention increases the operating voltage applied to the coil. For the purpose of providing a compressed air supply / discharge device capable of preventing an increase in size as a whole without increasing the number of turns of the coil, and saving power and space. There is.

[0019]

The features of the structure adopted by the first invention for solving the above-mentioned problems are that the exhaust solenoid valve has a communication passage for communicating the pneumatic equipment side to the outside. A valve casing having a valve seat formed in the middle of the passage, and a plunger that is slidably provided in the valve casing and has one end serving as a valve portion that is seated on and off the valve seat to open and close the communication passage, A core located at the other end of the plunger and fixedly provided in the valve casing, a piston slidably fitted in the core, and one end of the piston and the plunger. Urging means for urging the plunger and the piston in a direction to always separate the piston and the piston,
Compressed air is introduced as pilot pressure from the pneumatic equipment side so as to be located on the other end side of the piston and formed in the core so as to press the plunger toward the valve seat via the piston and biasing means. And a solenoid that is provided on the outside of the core and the plunger in the radial direction of the valve casing, is provided in the valve casing, and drives the plunger in the valve opening direction by being energized from the outside.

A feature of the configuration adopted by the second invention is that the exhaust solenoid valve has a communication passage for communicating the pneumatic equipment side to the outside, and a valve seat having a valve seat formed in the middle of the communication passage. A plunger that is slidably provided in the valve casing and has one end serving as a valve portion that is seated on and off the valve seat to open and close the communication passage; and the plunger located on the other end side of the plunger, A core fixedly provided in the casing, a piston slidably fitted in the core, one end side of which protrudes from the core and is fixed to the plunger, and the other end of the piston is positioned. A pressure chamber formed in the core, into which compressed air is introduced as pilot pressure from the pneumatic equipment side in order to press the plunger toward the valve seat via the piston, and a radial outside of the core and the plunger. Located in Provided in the valve casing, There's composed of a solenoid for driving the plunger in the valve opening direction by being energized from the outside.

[0021]

With the above structure, in the first aspect of the invention, the compressed air introduced from the pneumatic equipment side into the pressure chamber acts as a pilot pressure on the piston to generate a pressing force on the piston. The plunger can be pressed toward the valve seat via the valve, and if the pressing force by the piston at this time is made larger than the pressing force in the valve opening direction that acts on the valve part of the plunger from the valve seat side, the valve part of the plunger Can be reliably seated on the valve seat, and the plunger can be kept closed. When the plunger is opened, the driving force in the valve opening direction generated by the solenoid can be set to a relatively small driving force obtained by subtracting the pressing force in the valve opening direction from the pressing force by the piston, and the solenoid is energized. The voltage can be surely lowered.

Further, in the second aspect of the invention, the piston can directly press the plunger in the valve closing direction, and when the plunger is opened, the driving force in the valve opening direction generated in the solenoid can be surely reduced, so that the solenoid can be operated. The operating voltage for energization can be lowered.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIG. 4 described above are designated by the same reference numerals, and the description thereof will be omitted.

1 and 2 show the first embodiment of the present invention.

In the figure, reference numeral 30 denotes an exhaust solenoid valve used in this embodiment, and the exhaust solenoid valve 30 is a core 3 described later.
8, the piston 39 and the valve spring 41 are substantially the same as those of the exhaust solenoid valve 10 described in the prior art, and the valve casing 31 has an inlet 32B, an outlet 32C, and a valve seat 32D on the lid 32A side. Casing body 32
And a frame 33 and an end cover 34. Further, a valve portion 36 that is seated on and off the valve seat 32D is fitted to one end of a plunger 35 slidably fitted in the valve casing main body 32, and a valve spring 41 is fitted to the other end of the plunger 35. A bottomed hole 35A for housing is formed in the axial direction. A coil 37 as a solenoid is wound around the outer circumference of the valve casing body 32.

38 is located on the other end side of the plunger 35,
The core 38 fixedly provided in the valve casing main body 32 is shown, and although the core 38 is constructed in substantially the same manner as the core 19 described in the prior art, the core 38 has a stepped hole 38A in the axial direction. An annular step portion 38B is formed at an axially intermediate portion of the stepped hole 38A. When the coil 37 is excited, the core 38 adsorbs the plunger 35 as shown in FIG. 2 and opens the valve portion 36 of the plunger 35.

Reference numeral 39 denotes a piston slidably fitted in the stepped hole 38A of the core 38. The piston 39 is formed in a stepped cylindrical shape having a relatively small diameter, and the end surface of the piston 39 on the small diameter portion side. Is in contact with the other end of the valve spring 41. In addition, the end surface of the piston 39 on the large diameter side is attached to the mounting cylinder 4 described later.
2, the pressure chamber 40 is located in the stepped hole 38A of the core 38, and the pressure receiving area S1 of the piston 39 with respect to the pressure chamber 40 is the pressure receiving area S2 of the valve portion 36 with respect to the inlet 32B. Is larger than that (S2 <S1).

Reference numeral 41 designates a valve spring as an urging means disposed between the piston 39 and the bottomed hole 35A of the plunger 35. The valve spring 41 is composed of a coil spring having a relatively high rigidity, The spring load f is the normal pressure P1 of the compressed air supplied to the air chamber 8C of the air suspension 8.
, With respect to the pressure receiving area S1 of the piston 39,

[0029]

[Formula 1] f> S1 × P1.

Further, when the compressed air is being discharged from the compressor 1, for example, the air pipe 7 or the like is twisted or bent, and an excessive pressure P2 (P2> P1) is generated in the pipe line 5, This excess pressure P2 is the inlet 3 of the exhaust solenoid valve 30.
When acting on the valve portion 36 of the plunger 35 via 2B, the spring load f of the valve spring 41 is

[0031]

## EQU00002 ## The relation of f <S2.times.P2 is satisfied, and the valve portion 36 opens against the valve spring 41, thereby relieving the excess pressure P2 at this time to the outside.

Reference numeral 42 denotes a mounting cylinder that is fastened to the stepped hole 38A of the core 38 from the other end side of the core 38. One end side of the mounting cylinder 42 faces the pressure chamber 40 and the other end side thereof is the core 3
It projects from 8 in the axial direction. An air pipe 44 is connected to the protruding end side of the mounting cylinder 42 via a joint 43, and the air pipe 44 is connected to the air chamber 8C of the air suspension 8 together with the air pipe 7 via a joint 9. .
As a result, the compressed air supplied into the air chamber 8C of the air suspension 8 is also supplied as pilot pressure into the pressure chamber 40 via the air pipe 44, the joint 43 and the mounting cylinder 42, and the pressure P1 at this time is applied to the piston. The piston 39 is pressed (S1 x P1) by acting on it.
To press the plunger 35 toward the plunger 35, and the plunger 35 is always pressed in the valve closing direction via the valve spring 41.

The vehicle height adjusting / discharging device according to the present embodiment has the above-mentioned structure, and the basic operation thereof is not different from that of the prior art.

However, in this embodiment, the exhaust solenoid valve 3
No. 0 core 38 is formed with a stepped hole 38A, and the stepped hole 38A
A pressure chamber 40 is formed between the large diameter portion side end surface of the piston 39 slidably fitted inside and the mounting cylinder 42, and a part of the compressed air supplied into the air chamber 8C of the air suspension 8 is pressurized. The pressure P1 is introduced into the chamber 40 as a pilot pressure, and a valve spring 41 having a spring load f is arranged between the piston 39 and the bottomed hole 35A of the plunger 35.
On the other hand, the plunger 35 is constantly pressed in the valve closing direction via the valve spring 41 by the pressing force (S1 × P1) of the piston 39 having the pressure receiving area S1, and the valve portion 36 of the plunger 35 is seated on the valve seat 32D. The pressure receiving area S2 of the valve portion 36 with respect to the inflow port 32B in the state is
Since it is smaller than 1 (S2 <S1), the following operational effects can be obtained.

That is, the compressor 1 is driven by the electric motor 2,
When compressed air having a pressure of P1 is supplied from the compressor 1 into the air chamber 8C of the air suspension 8, the plunger 35 is closed with the pressing force (S1 x P1) from the piston 39 and the spring load f of the valve spring 41. By acting in the valve direction, the valve portion 36 of the plunger 35 can be reliably seated on the valve seat 32D, and the plunger 35 can be held in the valve closed state. Then, at this time, the piston 39 is pressed in the valve closing direction by the pressure P1 in the pressure chamber 40 and brought into contact with the step portion 38B of the stepped hole 38A, and the piston 39 is held at the stroke end in the valve closing direction. be able to.

Further, in this state, the pressure P1 from the inflow port 32B is applied to the valve portion 36 of the plunger 35 by the pressure receiving area S2.
And the valve portion 36 presses the valve in the opening direction (S2 x P1).
Is receiving pressure. However, the pressure receiving area S2 of the valve portion 36 is smaller than the pressure receiving area S1 of the piston 39 (S2 <S
1), the spring load f of the valve spring 41 is set to be larger than the pressing force (S1 x P1) of the piston 39 according to the equation (1). Therefore, the spring load f of the valve spring 41 should be substantially ignored. Is possible, and the plunger 35 at this time

[0037]

## EQU3 ## F = (S1 * P1)-(S2 * P1) = P1 * (S1-S2) The valve closing force F is always pressed in the valve closing direction.

When exhausting the compressed air from the air suspension 8, the coil 3 of the exhaust solenoid valve 30 is used.
7 is energized to excite the coil 37 and generate a magnetic force larger than the valve closing force F in the core 38, thereby driving the plunger 35 in the valve opening direction and moving the piston 39 to the position shown in FIG.
As shown in FIG. 3, the piston 38 can be slidably displaced in the valve opening direction in the stepped hole 38A of the core 38 against the pressure P1 of the pressure chamber 40.
The valve portion 36 of No. 5 can be separated from the valve seat 32D of the valve casing main body 32, and the inflow port 32B can be reliably communicated with the outflow port 32C.

Thus, according to this embodiment, the pressure P of the compressed air supplied into the air chamber 8C of the air suspension 8 is increased.
Even when 1 is increased, the exhaust solenoid valve 30 can be held in the closed state by the valve closing force F by the equation (3), and when the exhaust solenoid valve 30 is opened, the coil 37 is energized from the outside to turn on the coil 37. When magnetized to generate a magnetic force larger than the valve closing force F in the core 38, the plunger 35 is moved to the position shown in FIG.
The valve can be opened as shown in FIG. 3, and it is not necessary to change the operating voltage applied to the coil 37 at this time according to the pressure P1 of the compressed air, and the minimum operating voltage can be lowered.

Further, when the compressed air is being discharged from the compressor 1, for example, the air pipe 7 or the like may be twisted or bent to generate an excessive pressure P2 (P2> P1) in the pipe line 5. When the spring load f of the valve spring 41 is set so as to satisfy the equation (2), when the excess pressure P2 acts on the valve portion 36 of the plunger 35 via the inflow port 32B of the exhaust solenoid valve 30, In addition, the valve portion 36 can be opened against the valve spring 41, and the excess pressure P2 at this time can be reliably relieved to the outside.

Therefore, in this embodiment, even when the pressure of the compressed air supplied to the pneumatic equipment such as the air suspension 8 is increased, the operating voltage applied to the coil 37 is increased or the number of turns of the coil 37 is increased. No need to
It is possible to prevent the size of the whole from increasing, and to achieve various effects such as power saving and space saving.

Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. To do
The feature of this embodiment is that one end side of a piston 52 is fixed to the other end side of a plunger 51 slidably fitted in the valve casing main body 32, and a large diameter portion side end surface of the piston 52 and a mounting cylinder 42 are connected. A weak spring 53 as an urging means is disposed between the pressure chamber 40 and the pressure chamber 40.

Here, the plunger 51 is constructed in substantially the same manner as the plunger 35 described in the first embodiment, and the valve portion 36 is fitted on one end side thereof, but the other end side of the plunger 51. 51A of screw holes are formed in the axial direction. Further, the piston 52 slidably fitted in the stepped hole 38A of the core 38 has a small-diameter portion side protruding from the core 38, and a protruding end side thereof is screwed into a screw hole 51A of the plunger 51. Then, the weak spring 53 urges the piston 52 together with the plunger 51 in the valve closing direction with a weak spring load, so that the valve portion 36 of the plunger 51 is seated on the valve seat 32D.

Further, the piston 52 has a pressure receiving area S1 with respect to the pressure chamber 40, and the piston 52 has a pressing force (S1 x
It is always pressed in the valve closing direction at P1). The pressure receiving area S2 of the valve portion 36 is smaller than the pressure receiving area S1 of the piston 52 (S2 <S1), and the spring load of the weak spring 53 is so small that it can be substantially ignored. The plunger 51 can be constantly pressed by the valve closing force F in the valve closing direction.

Thus, in this embodiment having such a structure, it is possible to obtain substantially the same effects as the first embodiment, but especially in this embodiment, between the piston 52 and the mounting cylinder 42. It is only necessary to dispose the weak spring 53 in the first embodiment, and it is not necessary to use the valve spring 41 having a large spring load f as in the first embodiment, and the entire structure can be made more compact.

In the second embodiment, the piston 5
Although it has been described that the weak spring 53 is disposed between the mounting cylinder 42 and the mounting cylinder 42, instead of this, for example, the exhaust solenoid valve 3
If 0 is arranged in the vertical direction and the valve portion 36 is seated on the valve seat 32D by the weight of the plunger 51 or the like, it is not necessary to provide a biasing means such as the weak spring 53.

In each of the above-described embodiments, the case where the compressed air supply / discharge device is used for the vehicle height adjusting device of an automobile has been described as an example, but the present invention is not limited to this, and for example, an air valve,
It can also be applied as a drive source for other pneumatic equipment such as an air cylinder. The dryer 6 may be omitted when the water content in the compressed air does not substantially pose a problem.

[0048]

As described above in detail, in the first invention, the exhaust solenoid valve has a communication passage for communicating the pneumatic equipment side to the outside, and a valve casing having a valve seat formed in the middle of the communication passage. A plunger that is slidably provided in the valve casing and has one end serving as a valve portion that is seated on and off the valve seat to open and close the communication passage, and is located on the other end side of the plunger.
A core fixedly provided in the valve casing, a piston slidably fitted in the core, and disposed between one end side of the piston and the plunger, the plunger and the piston. Urging means for always urging the piston in a direction to be separated from each other, and is formed in the core at the other end side of the piston and presses the plunger toward the valve seat via the piston and the urging means. Therefore, the pressure chamber into which compressed air is introduced as a pilot pressure from the pneumatic equipment side and the valve casing are provided radially outside the core and the plunger, and the plunger is opened by energizing from the outside. Since it is composed of a solenoid that is driven in the valve direction, compressed air introduced from the pneumatic equipment side into the pressure chamber generates a pressing force on the piston, and this pressing force acts on the biasing means. The plunger toward the valve seat, and if the pressing force by the piston at this time is made larger than the pressing force in the valve opening direction that acts on the valve portion of the plunger from the valve seat side, the valve portion of the plunger is closed. The seat can be firmly seated and the plunger can be held in the valve closed state.

When the plunger is opened, the driving force in the valve opening direction generated in the solenoid can be set to a relatively small driving force obtained by subtracting the pressing force in the valve opening direction from the pressing force by the piston. The operating voltage for energization can be reliably lowered. Therefore, even when the pressure of the compressed air supplied to the pneumatic equipment such as the air suspension is increased, it is not necessary to increase the operating voltage for energizing the coil or increase the number of turns of the coil, and it is possible to increase the overall size. This can be prevented, and power saving and space saving can be achieved.

Further, according to the second aspect of the invention, the piston can directly press the plunger in the valve closing direction, and when the plunger is opened, the driving force in the valve opening direction generated in the solenoid can be surely reduced, so that the solenoid can be operated. Various effects are exhibited, such as lowering the operating voltage to be applied.

[Brief description of drawings]

FIG. 1 is an overall view showing a vehicle height adjusting device according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view showing a state in which an exhaust solenoid valve in FIG. 1 is opened.

FIG. 3 is a vertical sectional view showing a closed state of an exhaust solenoid valve according to a second embodiment.

FIG. 4 is an overall view showing a vehicle height adjusting device according to a conventional technique.

[Explanation of symbols]

 1 Compressor 2 Electric Motor 6 Dryer 8 Air Suspension (Pneumatic Equipment) 30 Exhaust Solenoid Valve 31 Valve Casing 32 Valve Casing Main Body 32B Inlet 32C Outlet 32D Valve Seat 35,51 Plunger 36 Valve 37 37 Coil (Solenoid) 38 Core 39 , 52 piston 40 pressure chamber 41 valve spring (biasing means) 43 joint 53 weak spring (biasing means)

Claims (2)

[Claims] 1. A compressor that supplies compressed air to a pneumatic device, and an exhaust solenoid valve that normally closes the valve and discharges the compressed air exhausted from the pneumatic device to the outside when opened by energization. In the compressed air supply / exhaust device, the exhaust solenoid valve has a communication passage that communicates the pneumatic equipment side to the outside, and a valve casing having a valve seat formed in the middle of the communication passage, and a slide inside the valve casing. A plunger that is movably provided and has one end serving as a valve portion that is seated on and off the valve seat to open and close the communication passage; and is disposed on the other end side of the plunger and fixed in the valve casing. A core, a piston slidably fitted in the core, and a piston disposed between one end of the piston and the plunger, and urging the plunger and the piston in a direction to always separate the piston and the piston. Means and Compressed air is introduced as pilot pressure from the pneumatic equipment side in order to press the plunger toward the valve seat via the piston and the biasing means, which is located on the other end side of the stone and is formed in the core. And a solenoid that is provided on the valve casing outside the core and the plunger in the radial direction and that drives the plunger in the valve opening direction by being energized from the outside. Compressed air supply and discharge device. 2. A compressor that supplies compressed air to a pneumatic device, and an exhaust solenoid valve that normally closes the valve and discharges the compressed air exhausted from the pneumatic device to the outside when opened by energization. In the compressed air supply / exhaust device, the exhaust solenoid valve has a communication passage that communicates the pneumatic equipment side to the outside, and a valve casing having a valve seat formed in the middle of the communication passage, and a slide inside the valve casing. A plunger that is movably provided and has one end serving as a valve portion that is seated on and off the valve seat to open and close the communication passage; and is disposed on the other end side of the plunger and fixed in the valve casing. A core, a piston slidably inserted in the core, one end of which protrudes from the core and is fixed to the plunger; and a piston that is positioned at the other end of the piston and is formed in the core. Front through piston The pressure chamber into which compressed air is introduced as pilot pressure from the pneumatic equipment side in order to press the plunger toward the valve seat, and the core and the plunger are provided on the valve casing at the outer side in the radial direction. A compressed air supply / discharge device, comprising: a solenoid that drives the plunger in a valve opening direction by being energized from.