CN116624615A

CN116624615A - Air pressure adjusting device

Info

Publication number: CN116624615A
Application number: CN202310147861.1A
Authority: CN
Inventors: 秋山幸大; 竹味幸彦; 小久江健
Original assignee: Aisin Co Ltd
Current assignee: Aisin Co Ltd
Priority date: 2022-02-21
Filing date: 2023-02-21
Publication date: 2023-08-22

Abstract

The invention provides an air pressure regulating device with high air discharge speed, compactness and low cost. An air pressure adjusting device (S) and an operating method thereof, wherein the air pressure adjusting device (S) comprises: a compressor (C) for compressing air taken in from the outside; a dryer (D) connected to the compressor (C) and filled with a reversible desiccant; a connection port (1) for supplying the air dehumidified by the dryer (D) to other equipment; an exhaust valve (2) provided between the compressor (C) and the dryer (D) and exhausting air from the dryer (D); and a switching valve (V) which is provided between the dryer (D) and the connection port (1) and switches between a first flow path (r 1) having a large air flow rate and a second flow path (r 2) having a small air flow rate.

Description

Air pressure adjusting device

Technical Field

The present invention relates to an air pressure adjusting device and an operating method thereof, wherein the air pressure adjusting device includes a compressor for compressing outside air, a dryer for dehumidifying circulated air, a connection port for supplying compressed air to other devices such as an air suspension, and an exhaust valve for exhausting air from the compressor, for height adjustment of a vehicle including the air suspension.

Background

Conventionally, as such an air pressure adjusting device, there is a device shown in patent document 1 (see paragraphs [0009] to [0013] and fig. 1), for example.

In particular, it is an object of the present invention to provide a compact and inexpensive pneumatic vehicle height adjusting device that can reduce the vehicle height in a short time, and has excellent dehumidification and regeneration efficiency of a desiccant in a dryer.

Specifically, the vehicle air conditioning system includes a compressor 1 for compressing air, a dryer 3 in which a reversible desiccant is sealed, a tank 5 for storing air, and an air suspension 7 for adjusting the vehicle height by increasing or decreasing the air pressure. Between the discharge side of the compressor 1 and the air suspension 7, a dryer 3, a one-way throttle valve 9 that performs a throttle function only in a direction from the air suspension 7 to the dryer 3, and a vehicle height adjusting valve 11 are provided in this order.

A first tank valve 13 is provided between the vehicle height adjusting valve 11 and the one-way throttle valve 9 and between the tank 5, and a second tank valve 15 is provided between the tank 5 and the suction side of the compressor 1. An exhaust valve 17 for exhausting the air in the circuit to the atmosphere is provided between the dryer 3 and the discharge side of the compressor 1.

These configurations are controlled by the control device 19, and when the vehicle height rises, the first tank valve 13 and the exhaust valve 17 are closed, and the vehicle height control valve 11 is opened to operate the compressor 1. On the other hand, when the vehicle height is lowered, the second tank valve 15 and the exhaust valve 17 are closed, and the vehicle height adjusting valve 11 and the first tank valve 13 are opened within a predetermined time from the start of the lowering control. In the case where the vehicle height does not drop to the target vehicle height after the lapse of the predetermined time, the first tank valve 13 is closed and the exhaust valve 17 is opened from this state to exhaust the remaining air of the air suspension.

In this way, the tank 5 storing air is provided on the exhaust circuit side, and when the vehicle height is lowered, the amount of compressed air in the air suspension that can be stored in the tank 5 is discharged to control the lowering of the vehicle height. That is, the capacity of the tank 5 is set to a small capacity of a degree that can be handled in a range of frequent vehicle height adjustment, and the predetermined time is set to a time required for performing vehicle height lowering control in the range. The compressed air discharged to the tank does not pass through the orifice, thereby shortening the vehicle height lowering time.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2002-87040

In the conventional air pressure adjusting device, the dry air discharged into the tank 5 can be supplied again to the suspension, and the vehicle height can be adjusted without compressing the external air again by the compressor when the vehicle height is next increased.

However, if the vehicle height does not completely drop to the target vehicle height within a predetermined time, the first tank valve is closed and the exhaust valve is opened from this state, and the compressed air in the air suspension is discharged from the exhaust valve 17 after passing through the one-way throttle valve 9 and the dryer 3. For example, when the passenger wants to quickly lower the vehicle height by a certain height, such as when getting on and off the vehicle or when carrying in and out the cargo, the passenger needs to discharge air through the one-way throttle 9, and the rapidity cannot be ensured.

In addition, it is necessary to provide a separate tank 5, which increases the volume and weight of the device, and also requires a valve or the like attached to the tank 5 to be controlled, thereby complicating the device structure.

As described above, in the conventional air pressure regulator, various problems to be solved such as the inability to effectively discharge air are present, and an air pressure regulator having a high air discharge speed, a compact structure, and a low cost is desired.

Disclosure of Invention

(feature structure)

The air pressure adjusting device according to the present invention is characterized by comprising:

a compressor for compressing air taken in from the outside;

a dryer connected to the compressor and filled with a reversible desiccant;

a connection port that supplies air dehumidified by the dryer to other equipment;

an exhaust valve provided between the compressor and the dryer and exhausting air of the dryer; and

and a switching valve provided between the dryer and the connection port and switching between a first flow path having a large air flow rate and a second flow path having a small air flow rate.

(Effect)

The switching valve of this structure is set up between desicator and connector. In general, air supplied to other equipment is dehumidified by a dryer, and when the air is discharged from the other equipment, moisture absorbed by the dryer is removed by flowing the air through the dryer, thereby regenerating the dryer. Therefore, an orifice for setting the air flow rate to a predetermined amount is provided between the dryer and the connection port.

However, in this configuration, a switching valve is provided between the dryer and the connection port, and the first flow path having a large air flow rate can be switched. Thus, for example, when air is discharged from another device, a large flow of air flows through the dryer, and the regenerating function of the dryer cannot be fully exhibited. However, by adopting this structure, the air of the other devices can be rapidly discharged.

Therefore, for example, when the other device to which the air pressure adjusting device is connected is an air suspension, the air in the air suspension can be quickly discharged, and the vehicle height can be quickly adjusted to be lowered.

The air pressure regulating device of the invention is provided with a switching valve at a position which is used for throttling the air flow rate in order to make the dryer function, and the air pressure regulating device can obtain a rapid air discharge effect by temporarily eliminating the air flow rate limitation of the dryer.

(feature structure)

In the air pressure adjusting device of the present invention, the switching valve includes: an annular valve seat, the outer periphery of which communicates with the connection port and the inner periphery of which communicates with the dryer; and a valve body that is in contact with or separated from the valve seat, wherein the first flow path is formed in a gap between the valve body and the valve seat in a state in which the valve body is separated from the valve seat, and the second flow path is formed in the valve body so as to communicate the connection port with the dryer in a state in which the valve body is in contact with the valve seat.

(Effect)

According to the present structure, the opening area of the first flow path is determined by the clearance formed on the entire circumference of the valve seat, and the opening area of the second flow path is determined by, for example, the size of the hole portion formed through the valve body. In particular, the first flow path formed over the entire periphery of the valve seat can obtain a large opening area according to the movement distance of the valve body. According to this configuration, the first flow path and the second flow path having different flow rates can be easily formed with a simple structure.

(feature structure)

In the air pressure adjusting device according to the present invention, the switching valve may include a solenoid, the valve body may be a plunger that reciprocates with respect to a coil of the solenoid, an opening of the second flow path with respect to the connection port may be formed on an outer surface of the valve body having a normal line intersecting the reciprocation direction, and an opening of the second flow path with respect to the dryer may be formed on an outer surface of the valve body having a normal line along the reciprocation direction, and a biasing member that biases the valve body toward the valve seat may be provided.

(Effect)

According to this configuration, the valve body is in contact with the valve seat when the switching valve is not energized, and the second flow path having a small flow rate is opened in normal times. Even when the pressure of the other device connected to the connection port is high in a state where the second flow path is functioning, the valve body does not operate accidentally due to the pressure of the other device because the second flow path is oriented in a direction intersecting the reciprocation direction of the valve body with respect to the opening of the connection port. Therefore, the air flow control can be reliably performed.

On the other hand, when high-pressure air is supplied to other equipment, the second flow path is directed in a direction along the reciprocation direction of the valve body with respect to the opening of the dryer. If the internal pressure of the dryer is high, a high pressure acts on the valve body in the press-in direction. Therefore, when the switching valve is energized, the valve body serving as the plunger moves rapidly, and high-pressure air can be supplied to other devices rapidly.

(feature structure)

In the air pressure adjusting device according to the present invention, the switching valve may include a solenoid, the valve body may be a plunger that reciprocates with respect to a coil of the solenoid, an opening of the second flow path with respect to the connection port may be formed by a gap between the valve body and the coil, an opening of the second flow path with respect to the dryer may be formed by a vertical hole formed through the valve body in the reciprocation direction, and a biasing member that biases the valve body toward the valve seat may be provided in the vertical hole.

(Effect)

In this configuration, the switching valve is not energized, and a gap is formed between the switching valve and the second flow path valve when the valve body abuts against the valve seat. Therefore, the valve body does not move accidentally due to high pressure or the like on the connection port side, and a stable throttle function can be exhibited.

In addition, the vertical hole may be formed in a direction along which the valve body reciprocates with respect to the valve body, and the processing is extremely easy, and the structure of the valve body is simplified. Therefore, the switching valve can be added to a general compressor mechanism or the like at low cost.

(feature structure)

In the air pressure adjusting device according to the present invention,

a second switching valve is provided between the compressor and the dryer and between the compressor and the exhaust valve, and

the air pressure adjusting device is provided with a circulation path for connecting the position between the switching valve and the connecting port with the second switching valve,

the switching by the second switching valve can be switched as:

a first state in which compressed air from the compressor is supplied to the dryer, and the circulation path is shut off; and

and a second state in which air from the compressor is supplied to the dryer in a reverse direction through the circulation path, and air having passed through the dryer is returned to the compressor.

(Effect)

According to this configuration, the direction in which air is supplied to the dryer can be changed by switching the second switching valve. This can effectively drain the moisture held by the dryer. For example, when air is discharged from the driven object, the switching valve is switched to the first flow path to increase the flow rate of air flowing through the dryer.

In this way, a large flow rate of air can be caused to flow through the dryer and air can be discharged from the exhaust valve, but at this time, the regeneration function of removing moisture from the desiccant in the dryer cannot be fully exerted, and the moisture adsorption amount of the desiccant increases toward the front side in the air flow direction in the interior of the dryer. The air passing through the dryer is discharged from an exhaust valve located at the downstream side of the dryer, but the desiccant is not sufficiently regenerated and moisture remains.

According to this configuration, in order to further discharge the residual moisture, the second switching valve is switched so that the air flow direction is reversed with respect to the dryer, and the air from the compressor can be supplied. Since the supply air is heated by the heat of operation of the compressor, the moisture adsorbed on the dehumidifier is easily removed. In addition, if the air flow direction is reversed, the high-temperature air flows from the side with the smaller amount of adsorbed moisture in the desiccant to the side with the larger amount of adsorbed moisture, so that the adsorbed moisture is not diffused and homogenized in the dryer. Since the portion with the largest amount of moisture is the most downstream side in this case, the moisture in the dryer can be effectively discharged.

(feature structure)

In the method of operating the air pressure regulator according to the present invention, it is preferable that after the second switching valve is switched to the second state, a first step of switching the switching valve to the first flow path to increase the air flow rate is performed, and then a second step of switching the switching valve to the second flow path to decrease the air flow rate and opening the exhaust valve is performed.

(Effect)

According to the method, in a first process, air heated by the operating heat of the compressor is counter-flowed in the dryer at a large flow rate and circulated between the dryer and the compressor. Thus, the moisture of the desiccant adsorbed to the dryer is absorbed into the circulating air without a large change in the gradient of the adsorption amount of the desiccant at each portion.

Next, in the second step, the switching valve is switched to the second flow path side having a small flow rate, and the exhaust valve is opened. Thus, the air slowly passes through the interior of the dryer, and the moisture adsorbed to the desiccant can be reliably removed.

In this way, according to the present method, the effect of removing the moisture adsorbed by the dehumidifier of the dryer can be improved, and the dryer can be maintained in a good state all the time.

Drawings

Fig. 1 is a side cross-sectional view showing the structure of an air pressure adjusting device according to a first embodiment.

Fig. 2 is a top cross-sectional view showing the structure of the air pressure adjusting device according to the first embodiment.

Fig. 3 is a block diagram showing the configuration of the air pressure adjusting device according to the first embodiment.

Fig. 4 is an explanatory diagram showing an operation mode of the switching valve according to the first embodiment.

Fig. 5 is an explanatory diagram showing an operation mode of the switching valve according to the second embodiment.

Fig. 6 is a block diagram showing the configuration of an air pressure adjusting device according to a third embodiment.

Fig. 7 is an explanatory diagram showing an operation mode of the air pressure adjusting device according to the third embodiment.

Description of the reference numerals

1. Connection port

2. Exhaust valve

C compressor

D dryer

d1 Dehumidifying agent

h1 Valve seat

R circulation path

r1 first flow path

r2 second flow path

r23 longitudinal hole

S air pressure adjusting device

V-switching valve

v1 force applying member

v2 coil

v3 valve body

V2 second switching valve

Detailed Description

First embodiment

(overview)

The air pressure adjusting device S according to the first embodiment of the present invention (hereinafter simply referred to as "device S") is shown in fig. 1 and 2 in a cross-sectional view, and fig. 3 is a block diagram of the configuration. Specifically, the device is provided with: a compressor C having a motor M and a piston P for compressing air sucked from the outside; a dryer D connected to the compressor C and filled with a desiccant D1; a connection port 1 for supplying the air dehumidified by the dryer D to other equipment; and an exhaust valve 2 disposed between the compressor C and the dryer D and exhausting air of the dryer D.

As shown in fig. 1, the motor M is disposed below the device S and has a rotation axis M1. A piston P is provided on the rotation shaft m1 via a connecting rod m2, and reciprocates inside a cylinder m 3. A suction valve c1 and a discharge valve c2 are provided at the top of the cylinder m3, the suction valve c1 taking in air from the outside, the discharge valve c2 guiding the air compressed by the piston P to the dryer D. The suction valve c1 and the discharge valve c2 are check valves.

The compressed air discharged from the discharge valve c2 is supplied to the lower portion of the dryer D through a supply passage 3 provided outside the cylinder m 3. The dryer D is filled with a reversible desiccant D1, and temporarily absorbs moisture condensed by compression of air. The desiccant D1 is fixed in position in the upper space by a perforated plate D3 provided in the lower portion of the dryer D together with a spring D2, so that the dehumidifiers D1 move with each other without being crushed.

(switching valve)

In the present embodiment, as shown in fig. 4, a switching valve V is provided at the top of the dryer D between the dryer D and the connection port 1. By this switching valve V, the air flow path between the dryer D and other devices can be switched between the first flow path r1 having a large air flow rate and the second flow path r2 having a small air flow rate. The purpose of the second flow path r2 having a small air flow rate is to reduce the amount of air flowing into the dryer D, reduce the internal pressure of the dryer D, promote the removal of moisture by the circulating dry air, and improve the reproducibility of the desiccant, particularly when the dryer D is exhausted.

The air compressed by the compressor C is supplied to other devices via the switching valve V, or the air discharged from the other devices is returned to the dryer D and discharged from the discharge valve 2. The dehumidifying agent D1 filled in the dryer D has reversibility, and condensed moisture is absorbed when air is compressed by the compressor C. When the compressed air is discharged, the moisture previously adsorbed on the desiccant D1 is brought to the outside again by the dry air returned to the dryer D.

As shown in fig. 2, the supply passage 3 of the compressed air from the compressor C toward the dryer D and the discharge passage 4 of the discharge air from the dryer D toward the discharge valve 2 are provided at different positions in substantially the same plane. The exhaust valve 2 has a solenoid, and is capable of changing the position of the valve body to an open state and a closed state.

As shown in fig. 3 and 4, the first flow path r1 is a large-diameter flow path, and the second flow path r2 is provided with an orifice having a throttle function.

As shown in fig. 3, the switching valve V includes a spring V1, and the second flow path r2 is normally selected. As shown in fig. 4, the switching valve V includes a cylindrical coil V2 and a valve body V3 that reciprocates at the center thereof. The valve v3 functions as a plunger of the solenoid. In this way, the first flow path r1 and the second flow path r2 of the present structure are switched by the advance and retreat of the valve body v3 with respect to the coil v2.

The valve body v3 is a cylindrical member, for example, and includes a spring chamber v4 having a spring v1 disposed therein in a central portion thereof. By this spring v1, the valve body v3 is biased to protrude from the coil v2. An annular valve seat H1 is formed integrally with the housing H in front of the protrusion of the valve body v3. An annular seal rubber v5 is attached to the tip of the valve body v3, for example, and can be brought into close contact with the valve seat h1. Fig. 4 (a) shows a state where the valve body v3 is in contact with the valve seat h1, and fig. 4 (b) shows a state where the valve body v3 is separated from the valve seat h1.

Two holes forming the second flow path r2 are formed in the valve body v3. One is a first hole r21 penetrating in the orthogonal direction with respect to the axial center X of the valve body v3, and the other is a second hole r22 communicating with the first hole r21 along the axial center X of the valve body v3 from the tip end of the valve body v3. Among them, the aperture of the second hole r22 is particularly determined to have a predetermined size so as to function as an orifice. The first hole r21 is opened in both directions of the valve body v3, and the total of the opening areas is set to be larger than the cross-sectional area of the second hole r22.

In fig. 4 (a) in which the second flow path r2 is selected, the valve body v3 abuts against the valve seat h1, and the first flow path r1 is closed. On the other hand, the second flow path r2 opens at the side of the valve body v3 protruding from the coil v2, and the dryer D communicates with the connection port 1. Fig. 4 (b) shows a state in which the switching valve V is energized to retract the valve body V3 against the biasing force of the spring V1, and the valve body V3 is separated from the valve seat h1. Thereby, the second channel r2 is moved into the coil v2 and closed, and the first channel r1 is selected.

The opening area of the first flow path r1 is determined by a clearance formed over the entire circumference of the valve seat h1, and the opening area of the second flow path r2 is determined by, for example, the size of a second hole r22 formed through the valve body v3. In contrast, the first flow path r1 formed over the entire periphery of the valve seat h1 can obtain a large opening area according to the moving distance of the valve body v3. According to this configuration, the first flow path r1 and the second flow path r2 having different flow rates can be easily formed with a simple structure.

Further, according to the present configuration, the switching valve V brings the valve body V3 into contact with the valve seat h1 when not energized, and the second flow path r2 having a small flow rate is opened in normal operation. Even when the pressure of the other equipment connected to the connection port 1 is high in a state where the second flow path r2 functions, the second flow path r2 faces a direction intersecting the reciprocation direction of the valve body v3 with respect to the opening of the connection port 1, and therefore the valve body v3 does not operate accidentally due to the pressure of the other equipment. Therefore, the air flow control can be reliably performed.

Further, in the valve body v3 of the present structure, when high-pressure air is supplied to other devices, the second flow path r2 faces the opening of the dryer D in a direction along the reciprocation direction of the valve body v3. The opening operation of the valve V3 is performed by energizing the switching valve V in principle, but if the internal pressure of the dryer D is high, a high pressure acts on the valve V3 in the press-in direction. Therefore, when the switching valve V is energized, the valve body V3 moves rapidly, and high-pressure air can be supplied to other devices rapidly.

As described above, in the present embodiment, the switching valve V is provided between the dryer D and the connection port 1, and the first flow path r1 having a large air flow rate can be selected. Thus, for example, when air is discharged from another device, a large flow rate of air can be caused to flow through the dryer D and the air can be discharged from the exhaust valve 2. At this time, although the regenerating function of removing moisture from the desiccant D1 of the dryer D cannot be sufficiently exhibited, according to the present configuration, air of other devices can be rapidly discharged.

Therefore, for example, in the case where the other device to which the air pressure adjusting device S of the present embodiment is connected is the air suspension a, the air in the air suspension a can be quickly discharged, and the vehicle height can be quickly adjusted to be lowered.

Action mode

The operation mode of the present device S is shown again with reference to fig. 3.

For example, the air suspension a of the present embodiment is mounted on a bus, and when the vehicle height is raised, the operation is performed as follows.

The control unit ECU sets the exhaust valve 2 to a closed state, the switching valve V to the second flow path r2, and the on-off valve 5 attached to the air suspension a to a closed state. Next, the compressor C is operated, and air is accumulated in the dryer D while being compressed. After a certain amount of compressed air is accumulated in the dryer D, the on-off valve 5 is opened to supply compressed air to the air suspension a.

At this time, in the dryer D, moisture in the compressed air is adsorbed by the dehumidifier D1, and moisture that becomes water droplets is temporarily stored in the lower portion of the dryer D. Moisture adsorbed by the desiccant D1 is carried away by the exhaust air as it passes through the dryer D in the opposite direction. The stored moisture in the lower part of the dryer D is discharged together with the exhaust air through the exhaust passage 4 and the exhaust valve 2.

When the air suspension a rises to a predetermined height, the on-off valve 5 is closed, and the compressor C is stopped. Thus, the discharge valve C2, which is a check valve provided in the compressor C, prevents the backflow of the compressed air in the dryer D, and air of a predetermined pressure is stored in the dryer D. The compressed air of the dryer D may be temporarily discharged by opening the operation exhaust valve 2.

When the vehicle height is lowered, the exhaust valve 2 is opened. In this way, when high-pressure air remains in the dryer D, the air starts to be discharged. Accordingly, the switching valve V is energized, and the switching valve V is set to the first flow path r1, so that the on-off valve 5 is opened. Thereby, the high-pressure air of the air suspension a is discharged from the exhaust valve 2 via the dryer D.

At this time, since the switching valve V is set in the first flow path r1, the high-pressure air of the air suspension a is rapidly discharged, and the vehicle height is rapidly controlled to drop. However, since a large flow rate of the exhaust air passes through the dryer D, the amount of moisture adsorbed by the desiccant D1 carried away by the exhaust air becomes small.

Second embodiment

Fig. 5 shows a second embodiment of the air pressure regulator S.

Here, the switching valve V is the same as the first embodiment in that it includes a coil V2 and a valve body V3 having a plunger function. However, the opening of the second flow path r2 with respect to the connection port 1 is formed by a gap between the valve body v3 and the coil v2. On the other hand, the opening of the second flow path r2 with respect to the dryer D is formed by a vertical hole r23 formed through the valve body v3 in the direction of the reciprocating movement. A spring V1 is provided in the vertical hole r23, and the spring V1 is a biasing member that biases the valve body V3 toward the valve seat h1 by applying a reaction force to the switching valve V.

As in the present configuration, if the second flow path r2 is formed by the gap between the valve body v3 and the coil v2, for example, the outer diameter of the valve body v3 may be smaller than the opening of the coil v2 by a predetermined value, and thus the configuration can be made very simple. If the valve body v3 is inclined and caught by the inner wall of the coil v2 during the reciprocation by providing the clearance, for example, a groove portion having a predetermined cross-sectional area may be formed in the surface of the valve body v3 along the reciprocation direction.

On the other hand, the vertical hole r23 formed in the valve body v3 is only required to form a through hole along the direction of the reciprocating movement of the valve body v3, and the processing is extremely easy, and the structure of the valve body v3 is simplified. Therefore, the switching valve V can be added to a general compressor mechanism or the like at low cost.

In addition, in the case of such a second flow path r2, as in the first embodiment, the high-pressure air on the connection port 1 side does not apply an external force in the direction of reciprocating the valve body v3, and the valve body v3 does not move accidentally. Therefore, a stable orifice function can be exhibited.

Third embodiment

In the third embodiment, an example of the air pressure adjusting device S is shown in which the circulation path R is provided between the compressor C and the connection port 1, and the moisture adsorbed by the dryer D is easily removed when the air is discharged from the air suspension a.

For example, in the prior art (japanese patent application laid-open No. 2002-087040) cited above, the device includes a compressor (1), a dryer (3), a low-pressure tank (5), and an air spring (7) to be controlled, and an exhaust valve (17) is provided, and the exhaust valve (17) discharges air in the circuit to the atmosphere from between the discharge side of the compressor (1) and the dryer (3).

In this device, when air is opened to the atmosphere, air in the air spring (7) or the low-pressure tank (5) flows into the dryer (3) through the orifice (9), and part of moisture adsorbed by the dryer (3) is removed and discharged from the exhaust valve (17). In this case, the regeneration of the dryer (3) is performed only when the air having a constant flow rate passes through the orifice (9), and therefore there is a limit to improving the regeneration efficiency of the dryer (3).

In addition, other conventional technologies (japanese patent application laid-open No. 2017-171285) include a compressor (24), a dryer (40), a tank (38), an air spring (22), and a separation check valve (33). By switching the main air line (63) and the auxiliary air line (67) by means of a separate check valve (33), the flow rates between the tank (38) and the air lines (63, 67) are changed, and a high/normal two exhaust speeds can be selected. This can increase the lowering speed of the vehicle height.

However, in this apparatus, the regeneration capacity of the dryer (40) is also limited. The dryer (40) is provided in the interior of the compressor (24) in parallel with the motor pump (48), and normally, when air from the motor pump (48) is sent to each air spring (22) via the dryer (40), moisture is adsorbed. On the other hand, only when air is reversed from the dryer (40) to the motor pump (48), the moisture can be discharged. When air supplied from the motor pump (48) to the air spring (22) is discharged, most of the air is opened to the atmosphere via a high-flow discharge valve (31) or a suspension valve (30) provided near the separation check valve (33), so that the air flowing back into the dryer (40) is small. Therefore, in this prior art, the regeneration capability of the dryer (40) cannot be said to be sufficient.

Therefore, the apparatus S of the present embodiment has a structure shown in fig. 6 and 7, for example, in order to improve the regeneration capability of the dryer D. Fig. 6 is a block diagram showing the configuration of the air pressure adjusting device S according to the present embodiment. Fig. 7 shows the operation modes of the components when removing moisture.

Specifically, as shown in fig. 6, a second switching valve V2 is provided downstream of the compressor C and upstream of the dryer D and the exhaust valve 2. Although not shown, the second switching valve V2 may be provided in a part of the casing of the compressor C, for example. The second switching valve V2 includes a solenoid, and is switchable between two positions. The second switching valve V2 has two ports on the upstream side and three ports on the downstream side. The two ports on the upstream side are connected to the upstream and downstream portions of the compressor C. The three ports on the downstream side are connected to an external air intake AI when external air is taken into the flow path, the circulation path R, and the compressor C toward the dryer D and the exhaust valve 2.

The circulation path R connects one of the ports on the downstream side in the second switching valve V2 with the position between the switching valve V and the air suspension a.

The second switching valve V2 can be switched between a first state in which air is compressed and supplied to the air suspension a, and a second state in which the air is released from the air suspension a and then the moisture adsorbed to the dryer D is removed, for example.

In the first state, the discharge port of the compressor C is connected to the dryer D and the exhaust valve 2, and the suction port of the compressor C is connected to the outside air suction portion AI (see fig. 7 (a) to (C)). At this time, the circulation path R is shut off. The first state is the same as the flow path structure in the first embodiment. In the second state, on the other hand, the discharge port of the compressor C is connected to the circulation path R, and the suction port of the compressor C is connected to the dryer D and the exhaust valve 2 (see fig. 7 (D) and (e)).

The operation modes of the air pressure adjusting device S in the first state and the second state are as follows.

Fig. 7 (a) shows a state in which the vehicle height is raised in the first state. The air compressed by the compressor C is sent to the air suspension a after the moisture is removed in the dryer D. At this time, the circulation path R is shut off, and the suction port of the compressor C communicates with the outside air suction portion AI.

Fig. 7 (b) shows a state in which the vehicle height is lowered at a normal speed. The circulation path R is shut off, and the switching valve V is switched to the second flow path R2, which is an orifice having a small air flow rate. The air from the air suspension a is taken into the air by the switching valve V, and the moisture adsorbed by the dryer D is discharged from the exhaust valve 2. This state is, for example, a case where it is not necessary to rapidly lower the vehicle height, and is, for example, a case where regeneration of the dryer D is performed at a normal exhaust speed in auto leveling, vehicle speed sensing, or the like. In this state, the air in a state where the flow rate is throttled and the pressure is reduced passes through the inside of the dryer D, and therefore the effect of removing the moisture adsorbed to the dryer D is high.

Fig. 7 (c) shows a state in which the vehicle height is rapidly lowered. At this time, the circulation path R is also in a shut-off state. The switching valve V is switched to the first flow path r1 having a large flow rate, and the air in the air suspension a is discharged at once through the switching valve, the dryer D, and the exhaust valve 2. At this time, the air having a large flow rate flows back through the dryer D, but the pressure of the air is high, and the amount of moisture in the air taken in from the moisture adsorbed in the dryer D is small. Therefore, the regeneration effect of the dryer D is small.

Fig. 7 (D) shows a first step of regenerating the dryer D. Here, the second switching valve V2 is set to the second state. The discharge port of the compressor C is connected to the circulation path R, and the suction port of the compressor C is connected to the dryer D. The switching valve V is switched to the first flow path r1 having a large flow rate. This state is set after the vehicle height is rapidly lowered, for example, by a person getting on or off a vehicle, loading a cargo, or the like. The air suspension a holds a prescribed amount of compressed air even after the vehicle height is lowered. Therefore, the inside of the dryer D and the circulation path R is equalized with the air suspension a to have a pressure greater than the atmospheric pressure. The switching operation of the second switching valve V2 can be performed by, for example, a switching operation by a user.

In this state, the compressor C is operated for a predetermined time, and air is circulated between the dryer D and the circulation path R. The air flowing through the dryer D flows reversely from the air suspension a side to the compressor C side. The circulated air is heated by heat generated by the compressor C or the like, and heats the inside of the dryer D. This facilitates the separation of moisture adsorbed on the dryer D.

The air is reversed in flow direction relative to the dryer D upon this heating, which is advantageous in maintaining the adsorption distribution of moisture inside the dryer D. The moisture adsorbed by the dryer D is moisture when the high-pressure air from the compressor C passes toward the air suspension a. Thus, the distribution of absorbed moisture is more in the upstream region near the compressor C and less in the downstream region near the air suspension a.

If the air is caused to flow in the same direction as the normal supply operation with respect to such a dryer D, the moisture on the upstream side of the dryer D is dispersed to the downstream side, and then the air flows back into the dryer D toward the exhaust valve 2, it is difficult to effectively remove the moisture remaining in the dryer D. In order to prevent this problem, in the present embodiment, the direction of air flow when the second switching valve V2 is in the second state is reversed.

Fig. 7 (e) shows a second step of regenerating the dryer D. Here, the second switching valve V2 is maintained in the second state, and the compressor C is stopped. Then, the exhaust valve 2 is opened, and the switching valve V is switched to the second flow path r2 having a small flow rate.

Thereby, the air having a pressure higher than the atmospheric pressure and heated to have taken in some moisture passes through the inside of the dryer D in a state where the flow rate is throttled and the pressure is reduced. Specifically, although the air between the suction port of the compressor C and the discharge passage 4 is directly discharged from the discharge valve 2, a part of the air in the circulation path R located downstream from the discharge port of the compressor C and the air between the connection port 1 and the switching valve V are discharged through the dryer D. In this way, the moisture adsorbed to the dryer D is efficiently taken in and discharged from the exhaust valve 2.

As described above, by providing the second switching valve V2 and the circulation path R, the air pressure adjusting device S can be obtained which can quickly reduce the vehicle height, suppress an increase in weight, reduce the mounting space, and reduce the cost. Further, the moisture held by the dryer D can be effectively discharged. In particular, by performing the first step and the second step by setting the second switching valve V2 to the second state after the air in the air suspension a is rapidly discharged and defining the flow direction of the air with respect to the dryer D, the effect of removing the moisture of the dehumidifier adsorbed to the dryer D is improved, and the dryer D can be maintained in a good state all the time.

Other embodiments

In the above embodiment, the switching valve V is integrally provided at the upper portion of the dryer D, but in the case where the product height of the air pressure adjusting device S is a problem in mounting, the switching valve V is not necessarily integrally formed with the dryer D, and may be connected by a separate connection pipe or the like.

The air pressure adjusting device of the present invention can be widely used as a device connected to a device that needs to rapidly discharge high-pressure air in other devices that supply high-pressure air.

Claims

1. An air pressure adjusting device is provided with:

a compressor for compressing air taken in from the outside;

a dryer connected to the compressor and filled with a reversible desiccant;

2. The air pressure regulating device according to claim 1, wherein,

the switching valve includes:

an annular valve seat, the outer periphery of which communicates with the connection port and the inner periphery of which communicates with the dryer; and

a valve body which is abutted against or separated from the valve seat,

the first flow path is formed in a gap between the valve body and the valve seat in a state where the valve body is separated from the valve seat,

the second flow path is formed through the valve body so that the connection port communicates with the dryer in a state where the valve body is in contact with the valve seat.

3. The air pressure regulating device according to claim 2, wherein,

the switching valve includes a solenoid, the valve body is a plunger that reciprocates relative to a coil of the solenoid,

an opening of the second flow path with respect to the connection port is formed in an outer surface of the valve body having a normal line intersecting the direction of the reciprocation,

an opening of the second flow path with respect to the dryer is formed in an outer surface of the valve body having a normal line along the direction of the reciprocating movement,

a biasing member is provided for biasing the valve body toward the valve seat.

4. The air pressure regulating device according to claim 2, wherein,

an opening of the second flow path with respect to the connection port is formed by a gap between the valve body and the coil,

the opening of the second flow path with respect to the dryer is formed by a longitudinal hole formed through the valve body in the direction of the reciprocating movement,

the vertical hole is provided with a biasing member for biasing the valve body toward the valve seat.

5. The air pressure regulating device according to claim 1, wherein,

by switching the second switching valve, switching can be performed as follows:

6. The air pressure regulating device according to claim 5, wherein,

after switching the second switching valve to the second state,

a first step of switching the switching valve to the first flow path to increase the air flow rate,

next, a second step of switching the switching valve to the second flow path to reduce the air flow rate and opening the exhaust valve is performed.