JPH0569722A - Vehicle suspension device - Google Patents

Abstract

PURPOSE:To improve the pump up performance of working fluid in the start of pump drive on the pump assembled in a vacant status, in a vehicle suspension device constituted active controllably. CONSTITUTION:In a suspension device which can carry out the active control while controlling the supply of working fluid pumped up and discharged from a reservoir tank 30 to a cylinder 4 by a pump 28 and the exhaust of working fluid returned back from the cylinder 4 to the reservoir 30, a short circuit passage 80 for shortcircuiting between the pump delivery side of the fluid passage 26 and the returning side to the reservoir tank in a fluid passage 60 and a manual open/close valve 82 for opening/closing the short-circuit passage manually are provided. When the working fluid in the reservoir tank 30 is pumped up in the pump 28 assembled in a vacant status after driving the pump 28, pipe resistance can be held down lower and the working fluid can be pumped up smoothly by keeping the manual open/close valve 82 in an open status.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension device constructed so that suspension characteristics can be changed by supplying and discharging a working fluid to and from a cylinder installed between a vehicle body and wheels.

[0002]

2. Description of the Related Art A vehicle suspension system generally comprises a combination of a mechanical spring and a shock absorber. For example, as disclosed in Japanese Unexamined Patent Publication No. 63-130418, there is a gap between a vehicle body and wheels. By installing a cylinder on the cylinder, and controlling the supply of the working fluid pumped up and discharged by the pump from the reservoir tank to this cylinder and the discharge of the working fluid flowing back from the cylinder to the reservoir tank, the vehicle height, hardness, softness, etc. There has also been proposed a so-called active suspension device configured so that suspension characteristics can be freely changed.

Assembly of the above-mentioned pump in such a suspension device is performed, for example, in a state where the working fluid in the pump is empty in consideration of the assemblability and safety. It is driven so that the working fluid in the reservoir tank is pumped into the pump and discharged.

[0004]

By the way, in the case where the working fluid is pumped up and discharged after the empty pump is assembled as described above, if the piping resistance in the fluid passage is large, the air in the pump will be deflated. As a result, the efficiency of pumping the working fluid deteriorates and the work efficiency decreases. Conventionally, when pumping the working fluid after this pump is assembled, an electromagnetic open / close type unload relief valve (a computer, etc. controls the pressure inside the fluid passage during active control). The pumping work can be performed by opening the valve when it becomes abnormally high, short-circuiting the pump discharge side and the return side to the reservoir tank, and controlling the valve that is provided to reduce the pressure to open. However, it was quite troublesome to control the solenoid on-off valve to open it during this pumping work.

In view of the above-mentioned problems, the present invention provides a so-called active suspension device for a vehicle, in which a pump assembled in an empty state is improved in pumping of a working fluid at the start of driving the pump. The purpose is.

[0006]

In order to solve the above-mentioned problems, a suspension device for a vehicle according to the present invention comprises a cylinder installed between a vehicle body and wheels, a reservoir tank for storing a working fluid, and A pump that discharges a working fluid, and a fluid passage that communicates between the cylinder, the reservoir tank, and the pump are provided, and the supply of the working fluid from the pump to the cylinder and the discharge of the working fluid from the cylinder to the reservoir tank are controlled. Accordingly, in the suspension device for a vehicle configured to change the suspension characteristic, a short-circuit passage for short-circuiting the discharge side of the pump and the return side to the reservoir tank of the fluid passage is provided, and the short-circuit passage is provided. Is provided with a manual on-off valve for manually opening and closing the short-circuit passage.

In the above structure, when a filter, a check valve and a cooler are provided in the fluid passage, the working fluid is passed through the short circuit passage without passing through the filter, the check valve and the oil cooler. It can be provided at a position where it can flow from the pump discharge side to the reflux side to the reservoir tank.

In addition to the above structure, another short-circuit passage for short-circuiting the discharge side of the pump and the return side to the reservoir tank of the fluid passage is provided in the fluid passage, and the fluid passage is provided in the short-circuit passage. A mechanical relief valve may be provided which closes when the pressure of the working fluid therein is below a predetermined value and opens when the pressure exceeds the predetermined value.

[0009]

As described above, according to the vehicle suspension device of the present invention, the short-circuit passage for short-circuiting the discharge side of the pump of the fluid passage and the return side to the reservoir tank is provided, and the short-circuit passage is provided with the short-circuit passage. Since a manual on-off valve for manually opening and closing the passage is provided, when the empty pump is installed and then the pump is driven to pump the working fluid from the reservoir tank, the manual on-off valve is operated to operate as described above. If the short-circuit passage is opened, the work of pumping the working fluid into the pump can be easily performed.

It is desirable that the short-circuit passage is provided at a position where the working fluid can circulate without passing through a portion having a large piping resistance in the middle of the fluid passage. In general, a filter, a check valve, a fluid cooler, and the like can be cited as the portion having a large piping resistance in the middle of the fluid passage. Therefore, when such a portion having a large piping resistance exists, the working fluid is If the short-circuit passage is provided at a position where the fluid can flow from the pump discharge side of the fluid passage to the return side to the reservoir tank without passing through the portion, the work of pumping the working fluid into the pump can be efficiently performed.

The advantage of providing the short-circuit passage and the manual on-off valve as described above is that the working fluid is pumped into the pump even when an electromagnetic on-off type unload relief valve is provided in the fluid passage. This is sufficiently effective because the troublesome work of controlling and opening the unload relief valve during the lifting work can be omitted, but instead of this unload relief valve, a mechanical relief valve (pressure of the working fluid in the fluid passage) is used. Is closed below a predetermined value and is provided with a valve which is opened by the pressure when the pressure exceeds a predetermined value), the effect becomes more remarkable. That is, such a mechanical relief valve is smaller in size and lower in cost than an electromagnetic opening / closing type unload relief valve, but when pumping the working fluid into the pump, the pressure in the fluid passage is maintained at a predetermined level. Since it does not open because it does not exceed the value, it is impossible to use this mechanical relief valve to smoothly carry out the work of pumping the working fluid into the pump. Therefore, in a suspension device in which a mechanical relief valve is provided instead of an electromagnetic opening / closing type unload relief valve, it is quite difficult to pump the working fluid into the pump after the empty pump is assembled. However, according to the present invention, even in such a case, it becomes possible to easily perform the work of pumping the working fluid into the pump.

Conversely, by providing the short-circuit passage and the manual on-off valve as in the present invention, it is possible to provide a small-sized and low-cost mechanical relief valve instead of the electromagnetic on-off type unload relief valve. Therefore, it can be said that the overall weight and cost of the suspension device can be reduced.

The above manual on-off valve can be operated only by a special tool, and if it is closed by the special tool after the pumping of the working fluid into the pump is completed,
Since it is possible to prevent a situation in which the user opens the on-off valve by mistake, normal active control can be performed without any trouble.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a vehicle suspension device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a vehicle suspension device according to the present invention, and FIG. 2 is an overall configuration diagram of the suspension device.

In the figure, the main elements corresponding to the right front wheel, the left front wheel, the right rear wheel and the left rear wheel are numbered with "FR", "FL", "RR" and "RL" respectively. However, in the following description, those reference numerals will be attached only when there is a particular need. The present embodiment is characterized in that, in this embodiment, as shown in FIG. 1, a short-circuit passage 80 that short-circuits the discharge side of the pump 28 and the return side to the reservoir tank 30 of the fluid passage, and the short-circuit passage is manually operated. Open / close valve 82
However, in order to make the description easier to understand, the configuration of the other parts excluding the short circuit passage 80 and the manual on-off valve 82 will be described first.

As shown in FIG. 2, a hydraulic cylinder 4 is fixed to each wheel of the vehicle body 2, and a hydraulic chamber 8 is defined by a piston 6 slidably fitted in the hydraulic cylinder 4. Is made. Piston rod 10 integrated with this piston 6
Wheels 12 are held in the. A gas spring 14 is communicated with the hydraulic chamber 8 via a hydraulic passage. The gas spring 14 has a gas chamber 18 and a liquid chamber 20 defined by a diaphragm 16 as a movable partition, and the liquid chamber 20 is in communication with the hydraulic chamber 8.

As shown in FIG. 1, three gas springs 14 are provided for the front wheels and two gas springs 2 are provided for the rear wheels, and they are connected to the hydraulic cylinders 4 in a parallel relationship with each other. Then, the hydraulic passages 22 communicating with the respective gas springs 14 are provided.
Each has an orifice 24. The unit composed of the combination of the hydraulic cylinder 4, the gas spring 14 and the orifice 24 has a basic function as a suspension device by the buffering action of the gas spring 14 and the damping action of the orifice 24. Become.

A high-pressure pipe 26F or 26R as a fluid passage is connected to each of the hydraulic cylinders 4, and a hydraulic fluid as a working fluid is supplied to and discharged from the hydraulic cylinder 4 through this pipe. The pump 28 for supplying the hydraulic fluid is composed of a vane pump driven by an engine, pumps the hydraulic fluid 32 from a reservoir tank 30, and supplies the hydraulic fluid through a common high-pressure pipe 26 to high pressures for front wheels and rear wheels. Pump to pipes 26F and 26R. The common high-pressure pipe 26 is provided with a filter 36 and a check valve 38 in this order from the upstream side, and the high-pressure pipes 26F and 26R for the front wheels and the rear wheels are provided with main accumulators 40F and 40R and a system oil pressure gauge for accumulating pressure. 42F and 42R are provided respectively. Further, in the pump 28, a relief valve 44 in the pump for returning the discharged hydraulic fluid to the suction side when the pressure on the discharge side abnormally rises.
Is provided.

The high pressure pipe 26F for the front wheel is a high pressure pipe for the right front wheel.
26FR and the left front wheel high-pressure pipe 26FL are branched, and these pipes 26FR and 26FL are respectively connected to the hydraulic chambers 8 of the right front wheel hydraulic cylinder 4FR and the left front wheel hydraulic cylinder 4FL. The same is true for the rear wheels. Also, from the above high pressure pipes 26F, 26R, the pilot passage 46F,
46R is branched, and these pilot passages 46F and 46R are connected to an electromagnetic opening / closing valve 48, respectively. Each high pressure pipe
The 26FR, 26FL, 26RR, and 26RL have a flow control valve 52, a pressurization-type on-off valve 54, and a relief valve 5 in order from the upstream side.
6. A cylinder oil pressure gauge 58 for detecting the cylinder internal pressure is provided.

As a result, the differential pressure before and after the flow control valves 52FR and 52FL for the front wheels is detected as the differential pressure between the pressure detected by the system oil pressure gauge 42F and the pressure detected by the cylinder oil pressure gauges 58FR and 58FL, respectively. It has become.
Similarly, the differential pressure across the flow control valves 52RR and 52RL for the rear wheels is detected as the differential pressure between the pressure detected by the system oil pressure gauge 42R and the pressure detected by the cylinder oil pressure gauges 58RR and 58RL. ing.

Then, the control unit 74 (which will be described later) controls the flow rate control valves 52FR, 52FL, 52RR, 52 based on the thus detected differential pressure.
The flow rate of the hydraulic fluid flowing through the RL is controlled.

The relief port of each relief valve 56 is connected to a reflux pipe 60F or 60R as a fluid passage. Each hydraulic oil liquid recirculation port of the electromagnetic on-off valve 48 is also connected to the above-mentioned recirculation pipe 60F or 60R. Return accumulators 62 for accumulating pressure are attached near the flow control valves 52 of the return pipes 60F and 60R, respectively.

The front wheel side recirculation pipe 60F and the rear wheel side recirculation pipe 60R are connected to a common recirculation pipe 60 leading to the reservoir tank 30 via an oil cooler 64 as a fluid cooler. The common return pipe 60 and the common high-pressure pipe 26 are communicated with each other by relief pipes 66 and 68, and a mechanical relief valve 70 and an ignition switch interlocking valve 72 are provided in the relief pipes 66 and 68, respectively. The connection between the relief pipes 66 and 68 and the common high-pressure pipe 26 is made on the upstream side and the downstream side of the check valve 38, respectively.

Next, the operation of the suspension device having the above structure will be described.

The operations of the ignition switch interlocking valve 72, the electromagnetic on-off valve 48 and the flow control valve 52 are controlled by a control unit 74 (see FIG. 2) which is, for example, a microcomputer. This control unit 74
Includes the system oil pressure gauge 42, a cylinder oil pressure gauge 58 provided for each hydraulic cylinder 4, each wheel 12FR, 12FL, 12
Acceleration sensor that detects sprung acceleration for each RR and 12RL
76, and each wheel 12FR, 12FL, 12RR, 12R
The output of the vehicle height sensor 78 that detects the vehicle height (that is, the cylinder stroke) is input for each L (in FIG. 2, the left rear wheel).
Only the oil pressure gauge 58 corresponding to 12RL, the acceleration sensor 76, and the vehicle height sensor 78 are shown). Then, the control unit 74 controls the supply and discharge of the hydraulic fluid based on the cylinder internal pressure, the sprung acceleration, and the vehicle height indicated by the hydraulic pressure gauge 58, the acceleration sensor 76, and the vehicle height sensor 78, respectively.

That is, first, the above-mentioned control unit
If the solenoid on-off valve 48 is closed by 74, the pump 28
The hydraulic fluid in the pilot passage 46 is stopped from being supplied to the pressurizing type opening / closing valve 54 in the electromagnetic opening / closing valve 48 even if the above-mentioned elements are operating normally. The pressurizing operation type on-off valve 54 connected to the pilot passage 46 is normally kept closed, and the operating pressure receiving port 54
It opens only when a specified operating pressure is applied to a. Therefore, when the supply of the hydraulic fluid to the operating pressure receiving port 54a is cut off as described above, the closed state is established. Thus, when the pressurizing type opening / closing valve 54 is closed, the suspension device exhibits characteristics based on the elastic modulus of the gas spring 14 and the throttle resistance of the orifice 24. That is, at this time, the suspension device becomes a so-called passive suspension.

On the other hand, when the electromagnetic opening / closing valve 48 is opened by the control unit 74 while the pump 28 or the like is operating normally, the pressure of the hydraulic fluid is applied to the operating pressure receiving port 54a of the pressurizing type opening / closing valve 54. Be done. As a result, the on-off valve 54 opens. In this way, the pressurizing type opening / closing valve 54 is opened,
Flow control valve 52 at the opening specified by control unit 74
When the piston is opened, for example, while the piston 10 is being displaced upward (to the left in FIG. 1), the hydraulic cylinder 4
When the hydraulic fluid is supplied to the hydraulic chamber 8 of No. 3, the displacement of the piston 6 is suppressed by the supplied hydraulic fluid.
The dynamic spring constant of the suspension device changes to increase. By supplying and discharging the hydraulic fluid in the hydraulic cylinder 4 in this manner, the throttle resistance of the orifice 24 and the gas spring 14
The same effect as changing the elastic modulus of is obtained, and the suspension device functions as a so-called active suspension device. It is also possible to control the vehicle height for each wheel by controlling the amount of hydraulic fluid in the hydraulic chamber 8 of the hydraulic cylinder 4.

During the above-mentioned supply / discharge control, if the pressure in the high-pressure pipe 26 (that is, the supply pressure) indicated by the system oil pressure gauge 42 exceeds the upper limit set value (for example, 130 Kgf / cm ² ), the operating pressure of the mechanical relief valve 70 is received. The mechanical relief valve 70 is opened by the working pressure received at the inlet 70a, whereby the working oil liquid is returned to the reservoir tank 30 and the abnormal pressure rise in the high-pressure pipe 26 is prevented. In addition, the control unit 74,
Only when the ignition switch is ON, the ignition switch interlocking valve 72 is controlled to be closed.
After the engine is stopped, the ignition switch interlocking valve 72 is opened and the high pressure state in the high pressure pipe 26 is released.

On the other hand, when the supply pressure drops below a predetermined value due to an abnormality in the piping system, the control unit 74 closes the electromagnetic opening / closing valve 48 to achieve fail safe. That is, when the electromagnetic opening / closing valve 48 is closed by the control unit 74, the hydraulic fluid in the pilot passage 46 flows to the pressurization type opening / closing valve 54 in the electromagnetic opening / closing valve 48 even if the pump 28 and the like are operating normally. Supply is cut off.
The pressure-operated on-off valve 54 connected to the pilot passage 46 is
It is normally closed and is opened only when a predetermined operating pressure is applied to the operating pressure receiving port 54a. Therefore, when the supply of the hydraulic fluid to the operating pressure receiving port 54a is cut off as described above, the closed state is established. When the pressurizing type opening / closing valve 54 is closed, the supply / discharge of the hydraulic fluid to / from the cylinder is cut off. Thus, when the pressurizing type opening / closing valve 54 is closed, the suspension device exhibits characteristics based on the elastic modulus of the gas spring 14 and the throttle resistance of the orifice 24. That is,
At this time, the suspension device becomes a so-called passive suspension.

As described above, the fail-safe against the abnormality of the piping system is basically performed by the control of the control unit 74, but in the present embodiment, the fail-safe is mechanically provided. .. That is, for example, the high-pressure pipe 26 is damaged and the flow control valve 52
If the hydraulic pressure (supply pressure) on the upstream side is abnormally decreased (for example, if it is lower than 90 Kgf / cm ² ), even if the electromagnetic opening / closing valve 48 is opened, the pressurization type opening / closing valve 54 has a predetermined No operating pressure will be applied. Thereby the on-off valve 54
Automatically closes, at which time the suspension device enters the passive state described above. Of course, even in this state, the basic function of the suspension device is maintained.

Next, the short-circuit passage 80 and the manual on-off valve 82, which are the features of the configuration of the present invention described above, will be described. As shown in FIG. 1, the short-circuit passage 80 is located closer to the pump 28 than the filter 36 and the check valve 38 of the common high-pressure pipe 26 serving as a fluid passage, and the oil cooler 64 of the common return pipe 60 serving as a fluid passage. Is also provided at a position short-circuiting with a point near the reservoir tank 30 on the downstream side.
The manual on-off valve 82 has a structure that can be operated only by a dedicated tool, and is provided in the short circuit passage 80.

After the pump 28 is assembled in an empty state, the pump 28 is driven to pump the hydraulic fluid in the reservoir tank 30.
When pumping into the 28, if the discharge side of the pump 28 and the return side to the reservoir tank 30 are short-circuited by opening the manual on-off valve, the hydraulic fluid will be filtered by the filter 36, the check valve 38 and the oil cooler. Since it is possible to circulate without passing through a portion having a large piping resistance such as 64, it is possible to smoothly perform the work of pumping the working oil liquid into the pump 28 together with the air removal from the pump 28. After the work of pumping the hydraulic fluid into the pump 28 is completed, the manual on-off valve is closed by a special tool, which prevents erroneous operation by the user and enables active control without any trouble. ..

Although the embodiment of the vehicle suspension device according to the present invention has been described above, the present invention is not limited to this embodiment. For example, the above-mentioned embodiment shows a basic example of the suspension device to which the present invention can be applied, and the details of the configuration may be changed. As an example of the change, in the above-mentioned embodiment, as a means for preventing an abnormal rise in the pressure in the common high-pressure pipe 26 during active control, the relief pipe by the operating pressure of the hydraulic fluid is used.
A mechanical relief valve 70 for opening 66 is provided. Instead of the mechanical relief valve 70, for example, an electromagnetic open / close type unload relief valve whose opening / closing is controlled by a control unit 74 may be provided.

Further, the short circuit passage may be provided at any position as long as it can smoothly pump the working fluid into the pump, and is not limited to the position shown in the above embodiment. Of course.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a vehicle suspension device according to the present invention.

FIG. 2 is an overall configuration diagram of the suspension device.

[Explanation of symbols]

 2 Car body 4 Cylinder 12 Wheels 26, 60 Fluid passage 28 Pump 30 Reservoir tank 36 Filter 38 Check valve 64 Fluid cooler 70 Mechanical relief valve 80 Short circuit passage 82 Manual open / close valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Nakayama 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (3)

[Claims] 1. A cylinder installed between a vehicle body and a wheel, a reservoir tank for storing a working fluid, a pump for pumping and discharging the working fluid, and a portion between the cylinder, the reservoir tank, and the pump. A suspension device for a vehicle, which is provided with a fluid passage communicating with it, and is configured to change suspension characteristics by controlling supply of the working fluid from the pump to the cylinder and discharge of the working fluid from the cylinder to the reservoir tank. In the above, a short-circuit passage for short-circuiting the discharge side of the pump of the fluid passage and the return side to the reservoir tank is provided, and a manual on-off valve for manually opening and closing the short-circuit passage is provided in the short-circuit passage. A vehicle suspension device characterized by the above. 2. A filter, a check valve, and a fluid cooler are interposed in the fluid passage, and the working fluid does not pass through the filter, the check valve, and the fluid cooler in the short-circuit passage. The suspension device for a vehicle according to claim 1, wherein the suspension device is provided at a position where it can flow from the discharge side of the pump to the return side to the reservoir tank. 3. Another short circuit passage is provided in the fluid passage for short-circuiting a discharge side of the pump of the fluid passage and a recirculation side to the reservoir tank. 3. A mechanical relief valve is provided which is closed when the pressure of the working fluid is below a predetermined value and which is opened when the pressure exceeds the predetermined value.
The vehicle suspension device described.