JPH018408Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fluid suspension for a vehicle such as an automobile.

[Conventional technology]

Generally, the suspension of vehicles such as automobiles is
It is preferable to change the spring characteristics depending on the driving condition because this improves riding comfort. For example, in normal straight running conditions on flat ground, it is preferable to have soft spring characteristics.
Further, it is said that it is preferable to have stiff spring characteristics when traveling around a curve or when the spring displacement is large.

In order to change the spring characteristics according to the driving conditions, conventional air suspension systems have been equipped with two or more air spring chambers.
No.-98876 and JP-A No. 53-26021 "Adjustable Suspension System for Vehicles") have been proposed.

This device is equipped with a switching valve that shuts off or communicates with the passage connecting two or more air spring chambers, and allows all the air spring chambers to work by placing the switching valve in communication. By turning off the switching valve, only a part of the air spring chamber is operated to obtain a hard spring characteristic.

[The problem that the idea aims to solve]

However, in this conventional device, when the switching valve is in the cutoff state, there is no particular problem when the pressure states of two or more air spring chambers are equal, but when the switching valve is in a different pressure state, the switching valve When the suspension is switched from the disconnected state to the open state, the spring characteristics of the suspension suddenly change, causing an unpleasant shock to the occupants and a sudden change in vehicle height.

Therefore, in this type of device, two or more air spring chambers are expected to be in different pressure states, and a computer performs difficult predictive control that takes into account the operation time of the switching valve and the operation of the suspension system. This creates the inconvenience of having to do so.

Therefore, the problem of the present invention is to solve the problem with a simple configuration.
The purpose is to prevent discontinuous changes in pressure from occurring when two air spring chambers are brought into communication from a blocked state.

[Means to solve the problem]

Therefore, in order to solve the above problems, this invention
It is characterized by having the following configuration.

A first fluid spring chamber having a fluid spring chamber configured to have a variable volume depending on the position of the wheel relative to the vehicle body.
A fluid suspension for a vehicle includes a fluid spring, and a second fluid spring connected to the first fluid spring via a fluid passage, wherein the fluid passage includes a first fluid passage having an on-off valve, and a second fluid spring connected to the first fluid spring through a fluid passage. The second fluid passage is provided in parallel with the first fluid passage and has a check valve, and the spring characteristics of the fluid suspension are changed by opening and closing the on-off valve.

At this time, if the check valve is configured to allow only the flow from the first fluid spring to the second fluid spring, the spring characteristics on the rebound side of the fluid suspension can be made variable. If the check valve allows only the flow from the second fluid spring toward the first fluid spring, the spring characteristics on the bound side can be made variable. In addition, by providing an on-off valve and a check valve in each of the first and second fluid passages, and by making the check valve allow flow only in one direction that is different from the other, the springs on both the rebound side and the bound side Characteristics can be made variable.

[Effect]

Now, when the on-off valve is closed, the fluid flow in one direction between the first fluid spring and the second fluid spring is blocked, which causes relative movement between the wheels and the vehicle body in the direction in which the flow is blocked. However, only the first fluid spring acts as a buffer against the spring, and a hard spring characteristic is obtained.
Next, by opening the on-off valve to allow flow between the first and second fluid springs so that both the first and second fluid springs act as a buffer, a soft spring characteristic can be obtained. If the spring characteristics on the bound side are increased by the action of a check valve when switching from closed to open, even if the on-off valve is closed, if the second fluid spring pressure becomes higher than the first fluid spring pressure, the second fluid spring pressure will increase. Fluid flows from the second fluid spring to the first fluid spring, and the pressure in both spring chambers becomes equal, and when the on-off valve is opened, the second
The first and second fluid springs are no longer communicated in a state where the fluid spring pressure of the first fluid spring is higher than the first fluid spring pressure, and the frequency of shocks that occur when switching the on-off valve is reduced. Similarly, when the spring characteristics on the rebound side are increased, when the on-off valve is opened, the first and second fluid springs are communicated with each other in a state where the first fluid spring pressure is higher than the second fluid spring pressure. This reduces the frequency of shocks that occur when switching on-off valves.

〔Example〕

Next, an embodiment based on the configuration of the present invention described above will be described based on the drawings.

FIG. 1 shows a first embodiment of the invention.

In FIG. 1, 10 is a first air spring chamber, 2
0 indicates a second air spring chamber, and the first air spring chamber 10 is partitioned by a diaphragm 11 to form an air chamber 12 and a hydraulic chamber 13. Similarly, the second air spring chamber 20 is also partitioned by the diaphragm 4 into an air chamber 22 and a hydraulic chamber 2.
3 is formed.

The hydraulic chamber 13 of the first air spring chamber 10 and the hydraulic chamber 23 of the second air spring chamber 20 are connected via two passages 30 and 40 arranged in parallel. These two passages 30 and 40 are provided with electromagnetic switching valves 31 and 41 as switching valves that respectively put the passages in a communication state or a cutoff state, and check valves 32 and 42 are also provided. . The check valve 32 provided in the passage 30 includes a first
The check valve 42 provided in the passage 40 is arranged to allow flow from the hydraulic chamber 13 of the air spring chamber 10 to the hydraulic chamber 23 of the second air spring chamber 20. It is arranged to allow flow from the hydraulic chamber 23 of the air spring chamber 20 toward the hydraulic chamber 13 of the first air spring chamber 10 . That is,
The passage 30 and the passage 40 are configured to be able to flow in only one direction by check valves 32 and 42, and the flow directions are different from each other.

Here, in this embodiment, the passage 30 corresponds to the first fluid passage and the passage 40 corresponds to the second fluid passage at the time of rebound, and the passage 40 corresponds to the second fluid passage at the time of rebound.
corresponds to the first fluid passage, and passage 30 corresponds to the second fluid passage.

A cylinder 9 is connected to a passage 15 connected to the hydraulic chamber 13 of the first air spring chamber 10, and a piston 8 is fitted into the cylinder 9 so as to be slidable therein. This piston 8 is connected to the lower arm 3 via a piston rod 7.
Piston rod 7 and lower arm 3 are connected by pin 7
This is done by a. Note that this lower arm 3 is for swingably attaching the wheel 1 to the vehicle body 2. The wheel 1 is supported by the lower arm 3 by a shaft 6, and the lower arm 3 is attached to the vehicle body 2 by a pin 5. There is. As a result, the piston 8 moves up and down as the wheel 1 swings up and down relative to the vehicle body 2, and hydraulic pressure is generated in the cylinder 9.
This hydraulic pressure is supplied to the respective hydraulic chambers 13 and 23 of the first air spring chamber 10 and the second air spring chamber 20, and provides a buffering effect in the first air spring chamber 10 and the second air spring chamber 20. will be done.

In addition, a small arm 3 is attached to the vehicle body 2 side of the lower arm 3.
The small arm 3a is adapted to come into contact with limit switches 51 and 52 and operate them by the rocking movement of the wheel 1 relative to the vehicle body 2. This limit switch 51 and 5
2 are attached to stays 53 and 54, and these stays 53 and 54 are attached to a guide 55 and a threaded rod 56. Stay 5
3 and 54 and the threaded rod 56 are respectively provided with forward and reverse X screws, and the rotation of the threaded rod 56 causes the stays 53 and 54, and therefore the limit switches 51 and 52, to move away from or approach each other. It is designed to move in the direction.

By operating the limit switches 51 and 52, the electromagnetic switching valves 31 and 41 are switched and operated. When limit switches 51 and 52 are inactive, both electromagnetic switching valves 31 and 41 are in communication, but when limit switch 51 is in an operating state, electromagnetic switching valve 41 is in a disconnected state. When the limit switch 52 is switched to the operating state, the electromagnetic switching valve 31 is switched to the cutoff state and operated.

The operation of the first embodiment having the above configuration will be explained next.

As shown in FIG. 1, the small arm 3a of the lower arm 3 is connected to the limit switches 51 and 5.
2, when the electromagnetic switching valves 31 and 41 are in a non-operating state where they are not in contact with any of them, both the electromagnetic switching valves 31 and 41 are in a common communication state, so that the second air spring chamber 20 is also connected to the passage 30
and 40 together with the first air spring chamber 10, and since both air spring chambers 10 and 20 work, the hydraulic pressure in the cylinder 9 is moved in and out of the hydraulic chambers 13 and 23 by the vertical movement of the piston 8. However, the spring characteristics are soft as shown by the solid line in FIG.

Next, when the wheel 1 swings greatly in the bounding direction and the small arm 3a of the lower arm 3 operates the limit switch 52, the electromagnetic switching valve 3
1 is activated, the passage 30 is cut off, and the second
The air spring chamber 20 is in communication only through the passage 40, and the second air spring chamber 20 is configured to be able to flow only from its hydraulic chamber 23 to the hydraulic chamber 13 of the first air spring chamber 10.

In this state, since the piston 8 moves upward, the hydraulic pressure in the cylinder 9 is compressed and supplied from the passage 15 to the air spring chamber, but the supply toward the second air spring chamber 20 is limited. , passages 30 and 40, only the first air spring chamber 10 works, and high-pressure hydraulic pressure flows into the hydraulic chamber 13, compressing the air chamber 12 and creating a buffering effect.

In this way, when the rocking of the wheel 1 exceeds the displacement that causes the limit switch 52 to be activated, only one of the first air spring chambers 10 acts, so its spring characteristics become stiff, and the limit switch 52 is now activated. If the point where 52 is activated and the electromagnetic switching valve 31 is cut off is point A shown in FIG. 3, then
The spring characteristics from this point A become a characteristic diagram shown by a broken line.

Note that when the wheel 1 begins to swing downward from the relative uppermost swing position, the piston 8 also moves downward from its top dead center position, and oil returns to the cylinder 9. in the second air spring chamber 2
0 oil also returns through the passage 40, but until the hydraulic pressure in the hydraulic chamber 13 of the first air spring chamber 10 becomes equal to or lower than the hydraulic pressure in the hydraulic chamber 23 of the second air spring chamber 20. , is blocked by the check valve 42, and when the pressure drops below the same pressure, it begins to flow. in general,
It is at point A shown in FIG. 3 that the passage 40 starts to flow, and at a displacement below this point A, the first air spring chamber 10 and the second
Since both of the air spring chambers 20 act, the characteristic diagram shown by is obtained.

Next, the limit switch 52 is deactivated, the electromagnetic switching valve 31 is switched to the communicating state, and
From the first air spring chamber 10 to the second air spring chamber 20
This allows oil to flow in this direction, but the switching of this electromagnetic switching valve 31 is generally performed using the limit switch 5.
Due to the influence of the hysteresis of the operation of 2 and the time required for the operation of the electromagnetic switching valve 31, the operation is performed a predetermined time after reaching point A, but by that time, the oil pressure in both hydraulic chambers 13 and 23 has already reached the passage 40. The two air spring chambers 10, 20
No change in oil pressure occurs in the oil pressure chambers 13, 23. That is, there is no discontinuous change in spring characteristics.

At this time, if the passages 30 and 40 are not configured as reciprocating one-way passages, and only one passage is used to shut off the electromagnetic switching valve, the electromagnetic switching valve will be in the open state after a predetermined delay time as shown in Fig. 3. Until , the spring characteristics change as shown by the dashed line in the continuation of the dashed line in , and then when the solenoid switching valve becomes in communication, the spring characteristics jump to the solid line in . do. In other words, discontinuous changes in oil pressure occur.

Of course, even when changing the spring constant under other conditions without depending on the vehicle height displacement, if the vehicle height displacement when the solenoid switching valve is closed differs from the vehicle height displacement when it is opened, discontinuity will occur. This causes a significant change in oil pressure.

Next, when the wheel 1 rebounds and the small arm 3a of the lower arm 3 operates the limit switch 51, the electromagnetic switching valve 41 is activated to shut off the passage 40, and the second air spring chamber 20 is connected to the passage 3.
0 is in communication, and the second air spring chamber 20
from the first air spring chamber 10 to the second air spring chamber 2
Distribution is possible only in the 0 direction.

In this state, since the piston 8 moves downward, oil is sucked into the cylinder 9 and flows into the cylinder 9 from the passage 15, but the oil in the hydraulic chamber 23 of the second air spring chamber 20 is Since the passages 30 and 40 are unable to flow from the hydraulic chamber 23 in the direction of the passage 15, only the first air spring chamber 10 works, and the oil in the hydraulic chamber 13 is pressed by the air chamber 12 and flows out. , acts as a buffer.

In this way, even in the driving state where the limit switch 51 is activated, only one of the first air spring chambers 10 is activated, so its spring characteristics are stiff, and the limit switch 51 is activated and the electromagnetic switching valve is activated. If the point where 41 is in the cut-off state is point B shown in FIG. 3, the spring characteristics from point B will be as shown by the broken line in the characteristic diagram.

Note that when the wheel 1 swings upward from the relative lowest movement position, the opposite effect to that of the limit switch 52 described above is performed, and the oil in the cylinder 9 is compressed, and the oil pressure gradually decreases. When the oil pressure becomes higher than the same pressure as the oil pressure in the oil pressure chamber 23 of the second air spring chamber 20, it flows into the oil pressure chamber 23 through the check valve 32 in the passage 30, and the oil pressure in the second air spring chamber 20 flows into the oil pressure chamber 23 again. Both the first air spring chamber 10 and the second air spring chamber 20 come to work, and the spring characteristics become as shown in the characteristic diagram.

Then, when the limit switch 51 is released and the electromagnetic switching valve 41 is in communication,
As in the case where the limit switch 52 is activated, the hydraulic pressures in both the hydraulic chambers 13 and 23 are already equal through the passage 30, so the hydraulic pressure is applied to the hydraulic chambers 13 and 23 in both the air spring chambers 10 and 20. No change occurs. That is, there is no discontinuous change in spring characteristics.

Furthermore, the positions of point A and point B shown in Fig. 3 are as follows:
By changing the mounting positions of the limit switches 51 and 52, it is possible to change them as desired. For example, now by turning the threaded rod 56, that is, by moving the stays 53 and 54 in a direction closer to each other, the limit switch 51
and 52 are placed close to each other, the spring characteristics can be plotted as ' or ' from points A' and B'.

FIG. 2 shows a second embodiment of the invention.

This second embodiment shows a fluid suspension in which both the first air spring chamber 10 and the second air spring chamber 20 are formed only by air chambers 12 and 22. are connected by passages 30 and 40, but the basic configuration is the same as the first embodiment shown in FIG. 1 described above. Therefore, in this second embodiment, the same or corresponding parts as those in the first embodiment shown in FIG.

Note that since the first air spring chamber 10 is formed only from the air chamber 12, this air chamber 12
The piston 8 is designed to act directly on the
A diaphragm 11 is provided at a portion on which the piston 8 acts.

The operation of this second embodiment is such that passages 30 and 4
This is the same as in the first embodiment described above, except that air flows through zero.

Although the present invention has been described above with reference to specific embodiments illustrated, the present invention is not limited to these embodiments, and various other embodiments are possible within the scope of the present invention.

For example, in each of the above-described embodiments, the case where the first air spring chamber 10 and the second air spring chamber 20 are both one is described, but the first air spring chamber 10 and the second air spring chamber 20 are It is also possible to use a plurality of either one or a plurality of both.

[Effect of idea]

As detailed above, according to the present invention, there is a first fluid passageway having an on-off valve that connects the first air spring chamber and the second air spring chamber, and this first fluid passageway. If the spring characteristics on the bound side are enhanced by a relatively simple configuration consisting of a second fluid passage provided in parallel and having a check valve, no matter what conditions the opening/closing valve is opened, the first The two spring chambers will no longer communicate with each other when the pressure in the second fluid spring chamber is higher than the pressure in the first fluid spring chamber, and if the spring characteristics on the rebound side are increased, the on-off valve will not open under any conditions. Even if it is open, the first
Since the pressure of the second fluid spring chamber is no longer communicated with higher than the pressure of the second fluid spring chamber, sudden changes in the spring characteristics of the air suspension are reduced, resulting in discomfort for the occupants. This has the excellent effect of reducing the inconvenience of sudden changes in vehicle height.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention;
FIG. 2 is a schematic diagram showing a second embodiment of the present invention, and FIG. 3 is a characteristic diagram showing spring characteristics based on the embodiment of the present invention. Explanation of symbols, 10...First air spring chamber, 20
... Second air spring chamber, 30, 40 ... Passage, 3
1, 41...Solenoid switching valve (switching valve), 32, 42
……non-return valve.

Claims (1)

[Scope of utility model registration request] A first fluid spring chamber having a fluid spring chamber configured to have a variable volume depending on the position of the wheel relative to the vehicle body.
A fluid suspension for a vehicle having a fluid spring and a second fluid spring connected to the first fluid spring via a fluid passage, wherein the fluid passage includes a first fluid passage having an on-off valve; A second fluid passage is provided in parallel with the first fluid passage and has a check valve, and the spring characteristics of the fluid suspension are changed by opening and closing the opening/closing valve. Characteristic fluid suspension for vehicles.