JPH074967Y2 - Air circuit for vehicle air suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an air circuit of an air suspension system used for suspending a vehicle.

[Prior Art] In an air suspension system for vehicle suspension, the compressed air supplied to the air suspension is generated by a compressor, and the compressed air supplied to the compressor is discharged not only from the surrounding atmosphere but also from the air suspension. A so-called semi-closed type air circuit that reuses even the air that has been used has already been proposed (Shokai 58-104711). According to such a semi-closed circuit, it is possible to reduce the intrusion of dust or water in the atmosphere into the circuit.

[Problems to be Solved by the Invention] In the above semi-closed circuit, in a mode in which air from the air suspension is guided to the air intake port of the compressor,
Since the air pressure in the air suspension is higher than the atmospheric pressure, a large load is applied to the compressor when the air is compressed by the compressor. That is, a large operating current is required for the compressor motor, which causes overheating of the motor,
There is a problem that the durability of the motor is reduced. On the contrary, in order to avoid such a problem, it is necessary to increase the capacity of the motor and use a large-capacity relay or a large-diameter harness, which leads to an increase in weight and cost of the vehicle.

There is also a method of lowering the compression ratio of the compressor in order to simply reduce the load on the compressor, but this causes the boosting performance in the mode of sucking air from the surrounding atmosphere to be reduced in the semi-closed circuit.

In view of the conventional problems of such a semi-closed circuit, the present invention solves the problem of realizing an air circuit capable of reducing the load on the compressor when compressing the air from the air suspension with a simple configuration. It was done.

SUMMARY OF THE INVENTION [Means for Solving the Problems] The present invention made to solve the above problems includes a compressor for supplying compressed air to an air suspension of a vehicle, and the air intake port of the compressor has a surrounding atmosphere. Is connected to a passage for inhaling air and a passage for inhaling air from the air suspension or a tank holding the air discharged from the air suspension, and the intake air to the compressor is connected to the air from any of those passages. In a switchable air circuit for an air suspension of a vehicle, in a passage for sucking air from the air suspension or a tank holding the air discharged from the air suspension, the confluence of the both passages and the If a throttle is provided between the air suspension or the tank, The one in which the gist of the air circuit for the air suspension of a vehicle, characterized in that a branch pipe communicating with the crank chamber of the compressor downstream position of the restrictor.

[Operation] In the air circuit according to the present invention, when the compressor compresses the air to supply the compressed air to the air suspension, there are two intake air sources. One is the case of inhaling air from the surrounding atmosphere, and the other is the case of inhaling air from the air suspension (or from the tank holding the air discharged from the air suspension). In the latter case, since the air pressure in the air suspension is higher than the atmospheric pressure, if the air is sucked in as it is, a large load is applied to the compressor during compression. However, in the air circuit according to the present invention, since the throttle is provided in the passage from the air suspension (or tank), the pressure of the air from the air suspension (or tank) is lowered by this throttle, and The pressure of the introduced air is low. Therefore, the load of the compressor during air compression does not increase even in the latter case.

Further, according to the present invention, since the branch pipe communicating with the crank chamber of the compressor at the downstream position of the throttle is provided, the crank chamber pressure is large when considering the case where the air from the air suspension side is sucked and compressed. It becomes higher than the atmospheric pressure and exerts an assisting action at the start of compression. Therefore, although the pressure is reduced by the throttle, the load reducing action at the time of compressing the air from the air suspension side, which is at a high pressure to some extent, is improved.

Incidentally, if attention is paid only to such an assist action, it is more advantageous to connect the branch pipe from the upstream position of the throttle to the crank chamber as in the comparative example described later. However, in this case, the back pressure of the crank chamber is always higher than the air sucked into the compression chamber during the intake stroke, and the load during intake increases.

On the other hand, in the present invention, the assist is provided to the crank chamber from the downstream position of the throttle. Therefore, when considering the intake stroke, the pressure in the compression chamber is not affected when the atmosphere is introduced or when the air on the air suspension side is introduced. And the crank chamber pressure become the same, and the intake operation is not hindered.

As described above, according to the present invention, the load at the time of compression can be reduced by reducing the pressure by the throttle, and the branch pipe can also exert an assisting action at the time of compressing the air on the air suspension side. Moreover, the arrangement position of the branch pipe is devised. By doing so, it is possible to prevent the intake stroke from being adversely affected at all.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an air circuit diagram of a vehicle height adjusting device as an embodiment to which the present invention is applied. This air circuit has a motor 1
A compressor 2 is provided which is driven by and compresses air. An intake pipe 5 is connected to an intake port 2a of the compressor 2 via an intake valve 4 that prevents a backflow. The intake pipe 5 is provided with a branch pipe 5a communicating with the crank chamber 2d on the back surface of the piston 2c of the compressor 2 to reduce the load at the time of starting the compressor 2.

A detailed partial cross-sectional view of the compressor 2 is shown in FIG. The branch pipe 5a is provided with a filter 5b, and abrasion powder generated at a sliding portion such as between the piston pin 2e and the bush 2f is sucked from the suction port 2a of the compressor 2 to cause a defective valve seat such as the intake valve 4. To prevent On the other hand, a passage 2h is provided between the chamber 2g in which the motor 1 of the compressor 2 is stored and the crank chamber 2d. If this passage 2h is not provided, the motor chamber 2g will be
When a pressure difference occurs between the crank chamber 2d and the crank chamber 2d, the grease of the bearing 2i is splashed to the crank chamber 2d or the motor chamber 2g. The passage 2h is provided to eliminate such a pressure difference between the two chambers. Here, too, abrasion powder generated in the sliding portion such as the motor brush portion of the motor 1 passes through the crank chamber 2d and the suction port 2a. A separate filter 2j is provided to prevent inhalation by the filter.

Returning to FIG. 1, the intake pipe 5 is a pipe 7 for sucking the ambient air and a well-known air suspension 28 provided on the wheel.
And a pipe 9 for inhaling air from. A pipe 7 communicating with the surrounding atmosphere is provided with a check valve 8 for preventing the air in the circuit from being released into the atmosphere, and an air filter 6 for filtering intake air is provided at the end thereof. . The pipe 9 to the air suspension 28 is provided with a fixed throttle 11 according to the present invention. Further, between the fixed throttle 11 and the air suspension 28, a down valve 32 that can be opened and closed.
Is provided.

A discharge valve 12 that can be opened and closed and a dryer 14 are connected to the discharge port 2b of the compressor 2 via an exhaust valve 10 that prevents the backflow of air to the compressor 2. The other side of the discharge valve 12 is open to the atmosphere, and a well-known reversible dehumidifying agent such as silica gel is enclosed in the dryer 14.
An accumulator 20 for storing compressed air is connected to the other side of the dryer 14 via a fixed throttle 16 and a check valve 18 for preventing backflow to the dryer 14, respectively. The accumulator 20 is provided with a pressure detection sensor 22 that emits an ON signal when the pressure inside the accumulator 20 is equal to or higher than a preset value P0. The predetermined value P0 is set to a pressure value sufficient to increase the vehicle height by supplying compressed air to the air suspension 28 at least once, for example. Further, the pressure inside the accumulator 20 is also installed with a relief valve 24 that opens when the pressure exceeds a preset pressure P1 which is higher than P0, and when the pressure inside the accumulator 20 rises excessively for some reason. , Protect the accumulator 20.

Further, the accumulator 20 is connected to the air suspension 28 via a lift valve 26 that can be opened and closed. By supplying air to the air suspension 28, the vehicle height can be raised, and by discharging the air, the vehicle height can be lowered to adjust the vehicle height. Further, a vehicle height detection sensor 30 for detecting a vehicle height that changes depending on the supply and discharge of air to and from the air suspension 28 is also provided. The vehicle height detection sensor 30 outputs a signal corresponding to a high state when the actual vehicle height is high, and a low state when the actual vehicle height is low, with respect to a reference vehicle height range of a predetermined width set in advance. Output a signal. In addition, the discharge valve 12, the up valve 26, the down valve 32
Is a normally closed (normally closed) two-position electromagnetic control valve, but other types of control valves can be used as long as they can be opened and closed.

The compressor 2 is not limited to being driven by the motor 1, but may be driven by an engine (not shown) via an electromagnetic clutch or the like. At this time, instead of the motor 1, the electromagnetic clutch or the like is controlled. The compressor 2 described later may be operated / stopped.

The motor 1, the discharge valve 12, the pressure detection sensor 22, the rising valve 2
6, the vehicle height detection sensor 30, the down valve 32, the electronic control circuit 5
Connected to 0. This electronic control circuit 50 is a well-known CPU
52, ROM54, RAM56 is a logic operation circuit mainly configured, in addition to them, an input / output circuit for performing input / output with the outside,
Here, the sensor input circuit 58 and the drive output circuit 60 are connected to each other via a common bus 62.

The CPU 52 inputs signals from the pressure detection sensor 22 and the vehicle height detection sensor 30 via the sensor input circuit 58. On the other hand, based on these signals and the data in ROM54 and RAM56, CP
The U52 outputs a drive signal to the motor 1, the discharge valve 12, the ascending valve 26, and the descending valve 32 via the drive output circuit 60 to control the supply / discharge of air to / from the air suspension 28.

Next, the processing performed in the electronic control circuit 50 will be described with reference to the flowchart of FIG.

When a key switch (not shown) is turned on, the vehicle height adjusting device executes the vehicle height adjusting control routine shown in FIG. 3 together with other control routines. First, the vehicle height detected by the vehicle height detection sensor 30 is read through the sensor input circuit 58 (step 100), and whether the read vehicle height is medium or not,
That is, it is determined whether or not it is within the reference vehicle height range (step 110). If it is determined that the vehicle height is medium, then whether the signal output from the pressure detection sensor 22 is an ON signal, that is, whether the pressure in the accumulator 20 is a predetermined value P0 or more, Is determined (step 120). When the pressure in the accumulator 20 is equal to or higher than the predetermined value P0, a drive signal is output to the discharge valve 12 via the drive output circuit 60 while the compressor 2 is stopped and the discharge valve 12 is opened. . At this time, the rising valve 26 and the descending valve 32 are kept closed without outputting a drive signal (step 130). When the discharge valve 12 is opened, the accumulator 20 is communicated with the atmosphere through the fixed throttle 16 and the dryer 14, and the compressed air flowing out from the accumulator 20 is compressed by the fixed throttle 16 when compressed by the compressor 2. It is well below the pressure of. The compressed air, whose pressure has been reduced and expanded, flows into the dryer 14, removes moisture from the dehumidifying agent in the dryer 14 to dry the dehumidifying agent sufficiently, restores the dehumidifying ability, and is released from the release valve 12 to the atmosphere. It

This control routine is repeatedly executed to release the compressed air in the accumulator 20 from the release valve 12 to the atmosphere.At some point, the process in step 120 causes the pressure in the accumulator 20 to fall below the predetermined value P0. If it is determined that
That is, when it is determined that the compressed air required for vehicle height adjustment is accumulated in the accumulator 20 only once, for example, the drive signal to the release valve 12 is stopped and the release valve 12 is stopped.
Is closed (step 140).

Even if the vehicle height is medium, if the pressure in the accumulator 20 is determined not to be equal to or higher than the predetermined value P0 by executing the processing of step 120, the compressor 2 is not operated and the discharge valve is not operated. 12, keeps the closed state without outputting a drive signal to the ascending valve 26 and the descending valve 32 (step 14
0). As a result, the compressed air in the accumulator 20 does not decrease, and the compressed air required for vehicle height adjustment is maintained.

If it is determined that the vehicle height detected by the vehicle height detection sensor 30 is not the middle level by executing the process of step 110, then in step 150, it is determined whether or not the detected vehicle height is lower than the reference range. To do. If it is determined to be low here,
Drive output circuit regardless of the detection signal of pressure detection sensor 22
A drive signal is output to the motor 1 via 60 to operate the compressor 2, a drive signal is output to the up valve 26 and opened, and drive signals are output to the discharge valve 12 and the down valve 32. Without closing, the compressor 2 is communicated with the accumulator 20 and the air suspension 28 (step 160). In this case, since the lowering valve 32 is closed, the compressor 2 is connected to the pipe 7 that communicates with the surrounding atmosphere.
The ambient air is sucked through the air filter 6 and the check valve 8, and the sucked air is compressed. The compressed air is dehumidified by the dehumidifying agent in the dryer 14, and is supplied to the accumulator 20 and the air suspension 28 via the check valve 18. By repeatedly executing this control routine,
If the vehicle height rises due to the supply of compressed air to the air suspension 28, and the vehicle height is determined to be medium by the execution of the processing in step 110 at some point, the processing in step 130 or 140 is executed. Thus, the operation of the compressor 2 by the motor 1 is stopped and the rising valve 26 is closed. As a result, the vehicle height is maintained at the middle level.

On the other hand, if it is determined that the vehicle height is not low, that is, is higher than the reference vehicle height range, by executing the process of step 150, the compressor 2 is operated, and a drive signal is output to the down valve 32 to open. Then, the discharge valve 12 and the rising valve 26 remain closed without outputting a drive signal, and the suction port 2a of the compressor 2 and the air suspension 28 are communicated with each other via the lowering valve 32 (step 170). As a result, all the exhaust air from the air suspension 28 flows into the compressor 2 through the down valve 32 and the pipe 9 and is compressed by the compressor 2. At this time, the high pressure of the air in the air suspension 28 is reduced by the fixed throttle 11, so that a large load is not applied to the compressor 2 during compression. Since the diameter of the fixed throttle 11 is set so that the air from the air suspension 28 is still higher than the atmospheric pressure even if the air is depressurized by the fixed throttle 11, the air from the surrounding atmosphere is operated by the check valve 8. Is never inhaled from the pipe 7. This compressed air is supplied to the accumulator 20 via the dryer 14 and the check valve 18 to accumulate pressure (step 170).

This control routine is repeatedly executed, the vehicle height is lowered by the exhaust from the air suspension 28, and at some point, when the vehicle height is determined to be the middle level by executing the processing of step 110, step 130 or By executing the processing of 140, the operation of the compressor 2 by the motor 1 is stopped and the lowering valve 32 is closed.

The signal of the pressure detection sensor 22, the compressor 2, the discharge valve 12, and the output from the execution of the processes of the steps 130, 140, 160 and 170,
Table 1 shows the states of the ascending valve 26 and the descending valve 32.

When the execution of the processing of steps 130, 140, 160 and 170 is completed, the execution of this control routine is once completed.

As described above, in the vehicle height adjusting device of the present embodiment, when the vehicle height rises, the rising valve 26 is opened, and the air from the surrounding atmosphere is sucked and compressed by the compressor 2 as it is, and the accumulator is obtained.
20, supply to air suspension 28 (steps 150, 1
70). When the vehicle height is lowered, the lowering valve 32 is opened, the compressor 2 is operated, and the exhaust air from the air suspension 28 is sucked and compressed through the fixed throttle 11 to be supplied and accumulated in the accumulator 2 (steps 150 and 160). . When it is detected that the pressure in the accumulator 20 is equal to or higher than the predetermined value P0 while the vehicle height is not adjusted, the release valve 12 is opened to release the compressed air in the accumulator 20 to the atmosphere (step 110, 120, 130).

Therefore, according to the vehicle height adjusting device of the present embodiment, when the vehicle height is lowered, the exhaust air from the air suspension 28 is sucked in through the fixed throttle 11, so that the high-pressure air in the air suspension 28 remains as it is in the compressor 2. The air with a reduced pressure is inhaled without being inhaled into. Therefore, when the intake air is compressed, the compressor 2 is not overloaded, the load on the motor 1 is reduced, and the operating energy is reduced. The fixed throttle 11 reduces the air discharge speed from the air suspension 28 when the vehicle height is lowered, and the time required to pressurize the air in the accumulator 20 (tank) is increased, but the diameter of the fixed throttle 11 is reduced. Since the load current of the motor 1 of the compressor 2 and the tank boosting time have a relationship as shown in FIG. 4 when changing, the motor load current and the tank can be set by appropriately setting the diameter of the fixed throttle 11. The boosting time and the boosting time can be set to any optimum values while considering the balance between the two.

In the pneumatic circuit of the above-described embodiment, the air from the air suspension 28 was directly guided to the compressor 2, but between them, a low-pressure tank that temporarily holds the air from the air suspension 28 (however, the internal The present invention can be applied even if the pressure is kept higher than the atmospheric pressure.

FIG. 5 is a schematic circuit diagram around the compressor 2 showing a comparative example of the present invention. In this comparative example, a branch pipe 9a corresponding to the branch pipe 5a of the above-described embodiment is led from the pipe 9 communicating with the air suspension 28 to the crank chamber 2d, and the fixed throttle 11 of the pipe 9 branches the branch pipe. It is provided on the downstream side of the branch point of the pipe 9a. According to this comparative example, the air from the air suspension 28 (or the low-pressure tank) is depressurized and the load on the compressor 2 is reduced as in the case of the above-described embodiment, and in addition, the air is discharged toward the crank chamber 2d. Since the high pressure air from the suspension 28 (or the low pressure tank) is guided without being reduced by the fixed throttle 11, the assist force from the back surface of the piston 2c at the time of compression of the compressor 2 is not diminished. Also has.

FIG. 6 shows a compressor 2 according to another comparative example of the present invention.
It is a schematic circuit diagram of the periphery. In this comparative example, the fixed throttle 11 of the above-described comparative example is replaced with a variable throttle 11b, and the throttle diameter is based on the detection value of the pressure sensor 9b provided in the pipe 9 that communicates with the air suspension 28 (or the low pressure tank). hand,
The electronic control circuit 50 is changed. The electronic control circuit 50 controls the diameter of the variable throttle 11b so that the pressure of the air taken into the compressor 2 becomes constant regardless of the pressure of the air from the air suspension 28. As a result, in addition to the effect of the comparative example of FIG. 5, there is an effect that the boosting performance of the compressor 2 can be made constant.

However, according to these comparative examples, contrary to these effects, the air suspension pressure before decompression is always applied to the crank chamber of the compressor, and the back pressure when considering the intake stroke is large, so that the intake operation is performed. Will be hindered.

On the other hand, when the branch pipe 5a is provided at the downstream position of the throttle 11 as in the embodiment of FIG. 1, the intake pressure and the crank chamber pressure are always the same during the intake stroke, which may interfere with the intake operation. Absent.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. .

Effect of the Invention In the semi-closed type air circuit, the intake air to the compressor can be switched between the ambient atmosphere and the air suspension (or a tank holding the air from the ambient air). In the present invention, of these, since the throttle is provided toward the air piping from the air suspension,
High pressure air from the air suspension is decompressed and can be sucked into the compressor. Therefore, even when the air from the air suspension is compressed, a large load is not applied to the compressor. Further, since it is not necessary to change the compression ratio of the compressor in order to reduce the load, the boosting performance of the compressor when sucking / compressing the surrounding atmosphere is not sacrificed. Further, in the present invention, a branch pipe is also provided so that the pressure in the crank chamber of the compressor becomes the same as the intake air pressure, and when compressing the air on the air suspension side, a back pressure above the atmospheric pressure is applied to compress the air. The effect of assisting the operation is exhibited, and moreover, in the intake stroke, the crank chamber back pressure becomes the same as the intake pressure, so that the intake operation can be executed smoothly.

That is, according to the present invention, the pressure at the time of compression can be reduced by reducing the pressure by the throttle, and the branch pipe can also exert an assisting action at the time of compressing the air on the air suspension side,
In addition, by devising the position of the branch pipe, it is possible to prevent the intake stroke from being adversely affected.

As a side effect, in the present invention, the combination of the boosting performance of the compressor and its load can be set to an arbitrary value by changing the diameter of the throttle, so the air suspension and the air from there can be different depending on the vehicle. Even if the pressure and capacity of the tank holding the air are different, it is possible to always design an air circuit suitable for each vehicle.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an air circuit and a control circuit of a vehicle height adjusting device according to a first embodiment of the present invention, FIG. 2 is a detailed partial sectional view of a compressor, and FIG. 3 is executed in the vehicle height adjusting device. FIG. 4 is a flow chart of a vehicle height adjustment control routine to be performed, and FIG. 4 is a graph showing the relationship between the time required for boosting the tank and the load current of the compressor motor when the diameter of the throttle is changed,
FIG. 5 is a schematic circuit diagram around a compressor showing a comparative example of the present invention, and FIG. 6 is a schematic circuit diagram around a compressor showing a comparative example of the present invention. 2 ... Compressor 2a ... Suction port 11 ... Fixed throttle 28 ... Air suspension

Front page continuation (72) Inventor Toshihiko Yamanaka 2-chome, Asahi-cho, Kariya city, Aichi Within Aisin Seiki Co., Ltd. (56) Reference JP-A-55-136611 (JP, A) Shoukai 60-184710 ( JP, U)

Claims (1)

[Scope of utility model registration request] 1. A compressor for supplying compressed air to an air suspension of a vehicle, wherein an air suction port of the compressor holds a passage for sucking ambient air and an air suspension or air discharged from the air suspension. In an air circuit for an air suspension of a vehicle, which is connected to a passage for sucking air from a tank and is capable of switching intake air to the compressor to air from any of those passages, from the air suspension or the air suspension. Inside the passage for sucking air from the tank that holds the discharged air, a throttle is provided between the confluence of the both passages and the air suspension or the tank, and the downstream position of the throttle. A branch pipe that connects to the crank chamber of the compressor The air circuit for the air suspension of the vehicle characterized by the above.