JPH0288319A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To eliminate abrasion powders, etc., produced from a fluid pump for discharging actuating fluid to be supplied to a cylinder and mitigate pulsa tion of working fluid at the same time by disposing a filter chamber at the actuating fluid discharge pipings of the fluid pump at a position close to the fluid pump. CONSTITUTION:Oil as working fluid for a liquid pressure cylinder is discharged from a hydraulic pump 36 of a fluid pump, and passes through a filter chamber 40 in common high pressure pipings 28 for the discharge pipings at a position close to the hydraulic pump 36. Working fluid entering from an entrance 40d of the filter chamber passes through a filter 40c to go out from an exit 40e of the filter chamber. Foreign matters such as abrasion powders produced at the hydraulic pump 36 can thus be eliminated, and because a predetermined volume exists in the filter chamber 40, pulsation of actuation oil liquid dis charged from the hydraulic pump is absorbed by the filter chamber 40 and mitigated.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention includes a cylinder installed between a vehicle body and wheels, and can change suspension characteristics by controlling the supply and discharge of working fluid to the cylinder. The present invention relates to a suspension device for a vehicle configured as described above.

(Prior Art) Some vehicle suspension systems include, for example,
C) As shown in Application Publication No. 0114757, a cylinder is installed between the vehicle body and the wheels, and by controlling the supply and discharge of working fluid to this cylinder, suspension such as vehicle height and hardness can be adjusted. There are so-called active suspension devices whose characteristics can be freely changed.

In such an active suspension device, a fluid pump that discharges high-pressure working fluid is usually used to supply the working fluid to the cylinder.

(Problem to be Solved by the Invention) Generally, when a fluid pump is used, a filter is provided on the suction side of the fluid pump, and the filter collects dust in the working fluid that is sucked in and discharged by the fluid pump. Efforts are being made to remove foreign substances such as However, fluid pumps also emit foreign matter, such as abrasion particles generated during fluid pump operation, and especially in active suspension systems such as those mentioned above, many parts such as high-precision valves are used. It is also necessary to sufficiently remove abrasion powder etc. emitted from such a fluid pump.

Further, generally when discharging working fluid from a fluid pump, for example in a piston type pump, pulsation of the working fluid occurs. Such pulsation is undesirable when the flow rate of the working fluid is controlled by a valve, and therefore it is desirable to absorb and alleviate this pulsation somewhere as much as possible.

In view of the above circumstances, an object of the present invention is to provide a suspension device for a vehicle that is capable of removing abrasion particles generated from a fluid pump and at the same time can alleviate pulsation of working fluid caused by the fluid pump. be.

(Means for Solving the Problems) In order to achieve the above object, the vehicle suspension device according to the present invention supplies and discharges working fluid to and from cylinders installed between the vehicle body and the wheels. A suspension system for a vehicle configured to be able to change suspension characteristics includes a fluid pump for discharging working fluid supplied to the cylinder, and a filter chamber is arranged in a position near the fluid pump in a working fluid discharge piping of the fluid pump. It is characterized by being set up.

The position near the fluid pump means closer to the fluid pump than a predetermined fluid circuit component, such as a proportional flow control valve, that needs to remove foreign matter such as wear particles installed in the fluid circuit. Preferably, the filter chamber is provided between the fluid circuit component closest to the fluid pump and the fluid pump.

(Function) In the vehicle suspension system with the above configuration, a filter chamber is provided in the working fluid discharge piping of the fluid pump in a position near the fluid pump. Not only foreign substances but also foreign substances such as abrasion particles generated from the fluid pump are removed from the working fluid by this filter chamber, so that the proportional flow control valve etc. are supplied with clean working fluid that does not contain foreign substances generated from the fluid pump. Trouble with fluid control valves, etc. caused by foreign matter in the working fluid can be avoided.

Further, the working fluid discharged from the fluid pump passes through the filter chamber, and since this filter chamber has a predetermined volume, it is used as an expansion chamber, and the pulsation of the working fluid can be absorbed and alleviated by the filter chamber. can.

(Examples) Hereinafter, the present invention will be described in detail with reference to examples shown in the drawings.

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

In addition, in the diagram, the main elements corresponding to the right front wheel, left front wheel, right rear wheel, and left rear wheel are numbered rFRJ.
rFLJ rRRJ and "RL" are added and shown, but in the following description, these codes are added only when particularly necessary.

As shown in FIG. 2, hydraulic cylinders 6 are installed between the vehicle body 2 and each wheel 4, and each hydraulic cylinder 6
are a cylinder body 8, a piston lO slidably inserted into the cylinder body 8, and a piston 10, respectively.
A hydraulic chamber 14 is defined in the cylinder main body 8 by the piston lO, and the upper end of the piston rod 12 is connected to the vehicle body 2. The main body 8 is connected to the wheels 4.

A gas spring 16 is communicated with the hydraulic chamber 14 via a hydraulic passage. This gas spring IB has a gas chamber 20 and a liquid chamber 22 defined by a movable partition wall 18 such as a diaphragm.
The liquid chamber 22 is connected to the hydraulic pressure chamber 14.

As shown in FIG. 1, three gas springs 16 are provided for the front wheels and two gas springs are provided for the rear wheels, and these springs are arranged in parallel with each other and communicate with each hydraulic cylinder 6 via a hydraulic passage 24. has been done. The hydraulic passages 24 communicating with each of these gas springs 1B are provided with orifices 2B having different opening areas.

A unit consisting of such a combination of the hydraulic cylinder 6, gas spring 16 and orifice 26 is a gas spring 1B.
The buffering effect of this and the damping effect of the orifice 26 provide a basic function as a suspension device.

As shown in FIG. 2, each hydraulic cylinder 6 is connected to a high pressure pipe 2.
B and is connected to a hydraulic power source 32 consisting of a hydraulic pump, a reserve tank, etc. via a reflux pipe 30, and these pipes 2
Hydraulic fluid is supplied to and discharged from each hydraulic cylinder 6 through these pipes 2g and 3G by a proportional flow rate control valve 84 provided at 8.30, thereby changing the suspension characteristics as appropriate.

Next, a hydraulic circuit for supplying and discharging hydraulic fluid to and from each of the hydraulic cylinders 6 will be described with reference to FIG.

The hydraulic pump 36 that supplies the hydraulic fluid pumps up the hydraulic fluid from the reserve tank 38 and passes the hydraulic fluid through the common high-pressure pipe 28 to the high-pressure pipes 28F for the front wheels and the rear wheels.
, pump to 28H. This common high-pressure pipe 28 includes filter chambers 40 and 40 in order from the upstream side. A check valve 42, a main accumulator 44 for accumulating pressure, and a system oil pressure gauge 4B are provided. Further, the hydraulic pump 3B is provided with an in-pump relief valve 48 that allows the discharged hydraulic fluid to flow back to the suction side when the pressure on the discharge side increases abnormally. Further, this hydraulic pump 3B for the suspension device constitutes a double pump together with the hydraulic pump 52 for the power steering device 50, and the hydraulic pump 36 is located closer to a drive source 54 such as an engine.

The high pressure pipe 28F for the front wheel is the high pressure pipe 28FR1 for the right front wheel.
It is branched into a high-pressure pipe 28FL for the left front wheel, and each of these pipes 28F R and 28F L is connected to each hydraulic chamber 14 of the hydraulic cylinder 6FR for the right front wheel and the hydraulic pressure cylinder 6FL for the left front wheel, respectively.
is communicated with. The same applies to the rear wheels.

Further, pilot passages 56F and 56R are branched from each of the high pressure pipes 28F and 28R, and these pilot passages 58F and 56R are connected to an electromagnetic switching valve 58, respectively. Each of the above high pressure piping 211FR.

In order from the upstream side, 28FL, 28RR, and 28RL include the proportional flow control valve 34 having a built-in pressure guarantee valve 60,
A pressurized on-off valve 64, a relief valve 8B, and an oil pressure gauge 88 are provided. The relief ports of each of the relief valves 66 are connected to the reflux pipe 30F or 80H. Further, each hydraulic fluid return port of the pressure guarantee valve 60 and the electromagnetic switching valve 58 is also connected to the above-mentioned return pipe 30F or 30R. These reflux pipes 30F.

A return accumulator 70 that performs a pressure accumulating function is attached to each of the 3QRs.

The front wheel side reflux pipe 30F and the rear wheel side reflux pipe 30R are connected to a common reflux pipe 30 that reaches the reserve tank 38 via a cooling circuit 72. The common reflux pipe 30 and the common high pressure pipe 28 are communicated by relief pipes 74 and 7B, and an unload relief valve 78 and an ignition key link valve 8o are provided in the relief pipes 74 and 76, respectively. . The relief pipes 74 and 7B are connected to the common high pressure pipe 28 on the upstream and downstream sides of the check valve 42, respectively.

Next, the operation of the suspension device having the above configuration will be explained.

The operations of the unload relief valve 78, the ignition key interlocking valve 80, the electromagnetic switching valve 58, and the proportional flow control valve 34 are controlled by a control unit 82 (see FIG. 2) comprising, for example, a microcomputer. This control unit 82 includes the system oil pressure gauge 4.
6. Oil pressure gauge 88 provided for each hydraulic cylinder 6, acceleration sensor 84 for detecting sprung speed for each wheel 4FR, 4FL, 4RR, 4RL, and each wheel 4FR.
, 4FL, 4RR, and 4RL, the output of the vehicle height sensor 86 that detects the vehicle height (that is, cylinder stroke) is input (in FIG. 2, the oil pressure gauge 68 corresponding to the left rear wheel 4RL,
Only the acceleration sensor 84 and vehicle height sensor 8B are shown). The control unit 82 controls the supply and discharge of hydraulic fluid based on the cylinder internal pressure, sprung mass acceleration, and vehicle height indicated by the oil pressure gauge 68, acceleration sensor 84, and vehicle height sensor 78, respectively.

That is, first, the control unit 82 switches the electromagnetic switching valve 58 to the return side (pressure-operated on-off valve 6 shown in the figure).
4), even if the hydraulic pump 36 etc. are operating normally, the pressure-operated opening/closing of the hydraulic fluid in the pilot passage 56 is not possible. The supply to valve 64 is cut off. The pressurized on-off valve 64 connected to the pilot passage 5B normally remains closed and opens only when a predetermined operating pressure is received at the operating pressure receiving port 84a. Therefore, when the supply of hydraulic fluid to the operating pressure receiving port 84a is cut off as described above, the operating pressure receiving port 84a is in a closed state. When the pressurized on-off valve B4 is thus closed, the suspension device exhibits characteristics based on the elastic modulus of the gas spring IB and the throttle resistance of the orifice 26. That is, at this time, the suspension device becomes a so-called passive suspension.

On the other hand, when the hydraulic pump 36 etc. are operating normally, the control unit 82 switches the electromagnetic switching valve 58 to the pressure supply side (the operating pressure inlet 64a of the pressure-operated on-off valve 64).
When the pressure-operated on-off valve 64 is in communication with the pilot passage 56), the pressure of the hydraulic fluid is applied to the operating pressure receiving port 84a of the pressurized on-off valve 64. This opens the on-off valve 64. In this manner, while the pressurized on-off valve 64 is open, the control unit 82 appropriately operates the flow rate control valve 34 to supply and discharge hydraulic fluid to and from each hydraulic cylinder 6. In other words, the flow rate control valve 34 By communicating the high pressure piping 28 with the hydraulic cylinder 6, the high pressure hydraulic fluid in the main accumulator 44 is supplied at its high pressure into the hydraulic chamber 14 of the hydraulic cylinder, and the flow control valve 34 connects the reflux piping 30. By communicating with the hydraulic cylinder 6, the hydraulic fluid in the hydraulic chamber 14 of the hydraulic cylinder is discharged toward the reserve tank 38 by the spring force of the gas spring 16, and by such supply and discharge of the hydraulic fluid. Control is performed to appropriately change the suspension characteristics. For example, when the piston IO is displaced downward (to the left in FIG. 1) relative to the cylinder body 8, the flow rate control valve 3 is adjusted to the opening specified by the control unit 82.
4 is opened and hydraulic fluid is supplied to the hydraulic chamber 14 of the hydraulic cylinder 6, the displacement of the piston 10 is suppressed by the supplied hydraulic fluid, and as a result, the dynamic spring constant of the suspension device is increased. It changes in the direction of . By supplying and discharging the hydraulic fluid into the hydraulic cylinder 6 in this way, the same effect as changing the throttling resistance of the orifice 2B and the elastic modulus of the gas spring 16 can be obtained, and the suspension device functions as a so-called active suspension device. do. It is also possible to control the vehicle height for each wheel by controlling the amount of hydraulic fluid in the hydraulic chamber 14 of the hydraulic cylinder 6. In addition,
In this embodiment, the hydraulic fluid is supplied and discharged based on the cylinder internal pressure.
Although this is performed based on the sprung mass acceleration and vehicle height, supply/discharge control may also be performed by taking into account vehicle speed, steering angle, lateral G, etc.

When the pressure in the high pressure pipe 28 indicated by the system oil pressure gauge 46 exceeds the upper limit set value, for example 160 kg/cj, the control unit 82 controls the unload relief valve 78.
is opened, and when the lower limit setting value, for example, 120 kg/c- is lowered, the unload relief valve 78 is closed.
60 kg/c- of high-pressure hydraulic fluid is stored, and an abnormal rise in pressure within the main accumulator 44 and high-pressure piping 28 is prevented.

Further, the control unit 82 closes the ignition key linked valve 80 only when the ignition key is on, and controls the valve 80 to open when the ignition key is off, thereby turning off the ignition key and stopping the engine. After the ignition key control valve 80 is opened, the high-pressure hydraulic fluid in the main accumulator 44 is discharged to the reserve tank 38 through the return passage consisting of the relief pipe 76, etc., and thereby the main accumulator 44 and the high-pressure The high pressure state within the pipe 28 is released.

Furthermore, if the hydraulic pressure (supply pressure) on the upstream side of the flow rate control valve 62 drops abnormally due to damage to the high-pressure pipe 28, for example, even if the electromagnetic switching valve 58 is located on the pressure supply side, the The predetermined operating pressure is not applied to the pressure-operated on-off valve 64. As a result, the on-off valve 64 automatically enters the closed state, and at this time the suspension device enters the aforementioned passive state. Of course, even in this state, the basic function of the suspension device is maintained, so there is no problem with the running of the vehicle. Furthermore, when the engine is stopped when the vehicle is parked, the hydraulic pump 3B is stopped and the ignition key link valve 80 is opened, so that the predetermined operating pressure is not applied to the operating pressure inlet 84a of the pressurized on-off valve 64. . Therefore, in this case, even if the electromagnetic switching valve 58 fails and remains positioned on the pressure supply side, the pressure-operated on-off valve B4 will be in the closed state, so that the proportional flow rate $ from the hydraulic cylinder 6 will be reduced. A situation in which the hydraulic fluid gradually flows out through the i1m valve 34 and lowers the vehicle height is reliably prevented.

In the vehicle suspension system configured as described above, hydraulic fluid, which is the working fluid of the hydraulic cylinder 6, is supplied, and the hydraulic fluid is discharged by the hydraulic pump 3B, which is a fluid pump. 3B is constituted by a swash plate type axial piston pump. The common high pressure pipe 28, which is the discharge pipe of the hydraulic pump 36, is provided with a filter chamber 4o in the vicinity of the hydraulic pump 3B as described above.

A specific example of the filter chamber 40 is shown in FIG. The illustrated filter chamber 40 is constructed by combining an upper housing 40a and a lower housing 40b, and has a filter 4°C disposed therein, and the working fluid that enters from the filter chamber entrance 40d passes through the filter 40c according to the path indicated by the arrow in the figure. and exits from the filter chamber outlet 40e.

The working fluid passes through the filter chamber 4o to remove foreign matter such as wear particles generated from the hydraulic pump 36,
In addition, since a predetermined volume exists within the filter chamber 40, the pulsation of the hydraulic fluid discharged from the hydraulic pump is absorbed and alleviated by the filter chamber 40.

FIG. 4 is a diagram showing another specific example of the filter chamber 40.

This filter chamber 40 is constructed by adding an accumulator 90 to the filter chamber 40 shown in FIG. 3 in order to further enhance the pulsation absorption and relaxation effect. The accumulator 90 includes a housing 90a and a piston 90b slidably disposed within the housing 90a. The piston 90b defines a gas chamber 90e and an oil chamber 90d. 90d communicates with the oil chamber 40g in the filter chamber through a communication hole 40" formed in the lower housing 40b of the filter chamber. In this specific example, the pulsation of the hydraulic fluid is caused by the displacement of the piston 90b. Since the pulsation absorption and relaxation effect is also absorbed and relaxed by

Figure 5 shows the upstream side 40h and downstream side 4°1 of the filter chamber 40.
A bypass passage 92 is provided to connect the
An example is shown in which an on-off valve 94 is provided which opens when the pressure on the upstream side 40h exceeds a predetermined value. With this kind of configuration,
Even if the filter 40c in the filter chamber 4o becomes clogged, the hydraulic fluid can be reliably supplied to the hydraulic cylinder 6, and there is no risk of hindering suspension control.

(Effects of the Invention) As described above, the vehicle suspension device according to the present invention is provided with a filter chamber near the fluid pump in the fluid pump discharge piping, so that the flow rate control valve etc. do not contain wear particles of the fluid pump. Clean working fluid is supplied, and there is no risk of problems with flow control valves or the like caused by foreign matter in the working fluid.

Further, the filter chamber is used as an expansion chamber, and therefore, the pulsation of the working fluid caused by the fluid pump can be absorbed and alleviated by the filter chamber.

[Brief explanation of the drawing]

1 and 2 are diagrams showing an embodiment of a vehicle suspension device according to the present invention, FIG. 1 is a hydraulic circuit diagram of the embodiment, FIG. 2 is an overall configuration diagram of the embodiment, 3 and 4 are cross-sectional views showing specific examples of the filter chamber, respectively, and FIG. 5 is a view showing an example in which a bypass passage is provided in the filter chamber portion.

Claims (1)

[Scope of Claims] A vehicle suspension device configured to change suspension characteristics by supplying and discharging working fluid to and from a cylinder installed between a vehicle body and a wheel, comprising: supplying working fluid to the cylinder; 1. A suspension device for a vehicle, comprising a fluid pump for discharging working fluid, and a filter chamber is disposed in a position near the fluid pump in a working fluid discharging piping of the fluid pump.