JPH02102941A - Suspension device of vehicle - Google Patents

Abstract

PURPOSE:To prevent drop of liquid, contamination due to liquid attachment, etc. by constructing the cylinder body of a liquid pressure cylinder in double cylindrical structure consisting of an inner and an outer cylindrical member, and using this outer cylinder as a reserve tank for liquid leaking from a rod guide. CONSTITUTION:The load of a car body is borne by oil pressure of a liquid pressure cylinder, and because this oil pressure must be high, risk of the liquid leaking between a rod guide 100b and piston rod 12 is large, but eventually leaking liquid passes a communication groove 100c to be accumulated in a cavity 104 formed from an inner and an outer cylindrical member 100, 102. That is, the outer cylindrical member 102 shall function as a reserve tank for leaked liquid. This eliminates such problems as drop of leaked liquid onto road surface, contamination of the external surface of cylinder body by the leaked liquid, etc.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a suspension device that includes a hydraulic cylinder disposed between a vehicle body and wheels, and supports a vehicle body load by the hydraulic pressure within the hydraulic cylinder. Regarding.

(Prior art) Some vehicle suspension devices include, for example, the
As disclosed in Publication No. 14365, this is a so-called hydropneumatic suspension (HPS) system, which consists of a hydraulic cylinder disposed between the vehicle body and the wheels, and a gas spring connected to the hydraulic cylinder. There is something to be done.

In such an HPS device, the vehicle body load is supported by the hydraulic pressure within the hydraulic cylinder.

In addition, in a suspension device that is equipped with an HPS device or a hydraulic cylinder that is not connected to a gas spring, the so-called so-called suspension device that allows the suspension characteristics to be controlled by independently supplying and discharging working fluid to and from the hydraulic cylinder for each wheel. Active suspension (AC8) devices are also known.

In this AC9 device as well, the vehicle body load is supported by the hydraulic pressure within the hydraulic cylinder.

(Problem to be Solved by the Invention) In a suspension device having a structure in which a hydraulic cylinder is disposed between the vehicle body and the wheels as described above, and the vehicle body load is supported by the hydraulic pressure in the hydraulic cylinder, ordinary suspension The hydraulic pressure inside the hydraulic cylinder is extremely high compared to the oil damper of There is a problem that the liquid inside the cylinder body tends to leak from between the cylinder bodies, and the leaked liquid falls onto the road surface or adheres to the outer surface of the cylinder body and becomes dirty.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a suspension device for a vehicle that solves the problems such as liquid falling and liquid adhesion staining as described above due to liquid leakage in a hydraulic cylinder.

(Means for Solving the Problems) In order to achieve the above object, a suspension device for a vehicle according to the present invention includes a hydraulic cylinder disposed between a vehicle body and a wheel, and a suspension system for a vehicle according to the present invention. In a suspension device that supports a vehicle body load by pressure, the cylinder body of the hydraulic cylinder has a double cylinder structure consisting of a cylinder and an outer cylinder, and the outer cylinder is configured as a reserve tank for liquid leakage from a rod guide. It is characterized by

The suspension device according to the present invention, whether it is a hydropneumatic suspension, an active suspension, or another type of suspension, has a suspension device that uses fluid in a hydraulic cylinder disposed between a vehicle body and a wheel. Any type of suspension device that supports the vehicle body load by pressure can be applied.

(Function) In the suspension device configured as above,
The liquid leaked from inside the cylinder body is stored in the outer cylinder of the cylinder body that forms a reserve tank, and the leaked liquid adheres to the outer surface of the resiling body (outer surface of the outer cylinder of the cylinder body) that falls on the road surface. Problems such as getting dirty can be avoided.

(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.
The symbols rFLJ, rRRJ, and [RLJ are added and shown, but in the following description, these symbols are added only when particularly necessary.

As shown in FIG. 2, a hydraulic cylinder 6 is installed between the vehicle body 2 and each wheel 4, and each hydraulic cylinder 6 has a cylinder main body 8 and a cylinder main body 8, and The piston 10 and the piston l slidably fitted into the piston 10 and the piston l
and a piston rod 12 integrated with O,
A hydraulic chamber 14 is defined within the cylinder body 8 by the piston lO, the upper end of the piston rod 12 is connected to the vehicle body 2, and the cylinder 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 16 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 IG are provided for the front wheels and two for the rear wheels, and they are arranged in parallel 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, the gas spring 16, and the orifice 2B includes the gas spring 16
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.
8 and reflux piping 30 to the hydraulic pressure 119f32 consisting of a hydraulic pump, reserve tank, etc., and each hydraulic cylinder 6 Hydraulic fluid is supplied and discharged to and from the suspension, 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.
, 28H. This common high-pressure pipe 28 is provided with a filter 40, a check valve 42, a main accumulator 44 for accumulating pressure, and a system oil pressure gauge 46 in this order from the upstream side. 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 suspension device hydraulic pump 3B is a hydraulic pump 5 for a power steering device 50.
2 constitute a double pump, and the hydraulic pump 3B 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 2 for the right front wheel [IFR
The high pressure piping 28FL for the left front wheel is branched into one high pressure piping 28FL, and each of these piping 28FR128FL is communicated with each hydraulic pressure chamber 14 of the hydraulic pressure cylinder 6FR for the right front wheel and the hydraulic pressure cylinder 6FL for the left front wheel, respectively. The same applies to the rear wheels. Further, pilot passages 56F and 51 are branched from the high pressure pipes 28F and 28R, and these pilot passages 56
F and 58R are respectively connected to the electromagnetic switching valve 58. Each of the above high pressure piping 28FR.

For 28FL, 28RR, and 28RL, sequentially from the upstream side,
The proportional flow rate control valve 34 with a built-in pressure guarantee valve BO, a pressurized on-off valve 64, a relief valve 6B, and an oil pressure gauge 68 are provided. The relief ports of each of the relief valves 66 are connected to the reflux pipe 30F or 3QR. 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 30H. These reflux pipes 30F.

A return accumulator 70 that performs a pressure accumulating function is attached to each of the cylinders 30R.

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 through relief pipes 74 and 76, and an unload relief valve 78 and an ignition key link valve 80 are provided in the relief pipes 74 and 7B, 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 68 provided for each hydraulic cylinder 6, acceleration sensor 84 for detecting sprung mass acceleration for each wheel 4FR, 4FL, 4RR, 4RL, and each wheel 4FR.
, 4FL, 4RR, and 4RL, the output of the vehicle height sensor 8B 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 86 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, when the electromagnetic switching valve 58 is positioned on the return side (the state shown in the figure) by the control unit 82, even if the hydraulic pump 88 etc. are operating normally, the hydraulic fluid in the pilot passage 56 is The supply to the pressurized on-off valve operating pressure receiving port 64a is cut off, the pressurized on-off valve B4 is closed, and the suspension device exhibits characteristics based on the elastic modulus of the gas spring 16 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 bomb 3B etc. are operating normally, if the control unit 82 positions the electromagnetic switching valve 58 on the pressure supply side (the side opposite to the return side),
The pressure of the hydraulic fluid is applied to the operating pressure receiving port 64a of the pressurized on-off valve 64. This opens the on-off valve 64.

In this state that the pressurized on-off valve 64 is opened, the control unit 82 controls the flow rate control valve 3.
4 is operated as appropriate to supply and discharge hydraulic fluid to and from each hydraulic cylinder 6, and control is performed to appropriately change the suspension characteristics by supplying and discharging hydraulic fluid. In other words, by supplying and discharging hydraulic fluid into the hydraulic cylinder 6, the same effect as changing the throttling resistance of the orifice 2B and the elastic modulus of the gas spring 18 can be obtained, and the suspension device can be used as a so-called active suspension device. Function. 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.

The unload relief valve 78 is opened by the control unit 82 when the pressure indicated by the system oil pressure gauge 4B exceeds the upper limit set value, and is closed when the pressure falls below the lower limit set value. High pressure hydraulic fluid with a predetermined pressure range is stored.

Further, the control unit 82 closes the ignition key link valve 80 only when the ignition key is on, and controls the release valve 80 to open when the ignition key is off, thereby turning off the ignition key and stopping the engine. After that, the ignition key control valve 80 is opened and the high pressure hydraulic fluid in the main accumulator 44 is discharged to the reserve tank 38 via the relief pipe 76, thereby reducing the high pressure state in the main accumulator 44 and the high pressure pipe 28. is canceled.

FIG. 3 is a rear view (view from the rear of the vehicle body) showing an embodiment of the hydraulic cylinder 6FR for the right front wheel JFR and the gas spring 16 connected to the hydraulic cylinder 6FR.

As shown, the cylinder body 8 of the hydraulic cylinder 6FR is connected to the wheel 4FR via a wheel support 9σ, and the piston rod 12 is connected to the vehicle body 2 via a strut mount rubber unit 92. Between the strut mount rubber unit 92 of the piston rod 8 and the cylinder body 8, there are, in order from the top, a support member 94 that supports the gas spring 1B at its upper end, and a rubber stopper 96 that covers the top of the cylinder body 8. It is provided. A hydraulic passage 98 communicating with a hydraulic chamber 14 (not shown in FIG. 3) in the hydraulic cylinder is formed in the piston rod 12, and a hydraulic passage 98 and a gas spring 1B are formed in the support member 94. A hydraulic passage 24 having the above-mentioned orifice 2B communicating with the liquid chamber 22 is formed.

The cylinder body 8 is an inner cylinder that functions as the original cylinder body 8, as shown in FIG. 4, which is a sectional view of the hydraulic cylinder, and FIG. 5, which is a sectional view taken along the line v--V in FIG. 100
and an outer cylinder 102 fitted onto the outer periphery of the inner cylinder 100 at a predetermined interval. That is,
The inner cylinder 100 has a bottom plate 100a, and has a piston 1 inside.
A communication hole 10a is formed in the piston lO to communicate between the upper and lower sides of the piston, and a piston rod 12 is connected to the piston lO, and the piston rod 12 is provided at the upper part of the inner cylinder 100. The inner cylinder 100 is slidable inside the rod guy Ftoob which functions as an M member.
A hydraulic chamber 14 is formed by the bottom plate 100a and the rod guide toob. The inner cylinder 100 is covered by an outer cylinder 102 which also has a bottom plate 102a, and there is a gap between the rod guide toob and the rod 12 between the inner circumferential surface of the outer cylinder extension and the outer circumferential surface of the rod guide 100b. A communication groove 1000 through which leaked oil passes is formed, and this communication groove 100c communicates with a cavity 104 formed by the outer cylinder 102 and the inner cylinder 100.

In the active suspension of this embodiment, the vehicle body load is supported by the oil pressure in the hydraulic cylinder 6, and therefore, the oil pressure becomes high pressure, and there is a strong possibility that the oil will leak from between the mouth rad guide toob and the piston rod 12. Even if leakage occurs, the leaked oil passes through the communication groove 100c and is stored in the cavity 104. In other words, the outer cylinder 102 is configured to function as a reserve tank for this leaked oil, thereby eliminating problems such as the leaked oil falling onto the road surface and the staining of the outer surface of the cylinder body due to the leaked oil. be able to.

As shown in FIG. 5, the outer cylinder 102 has a part formed as a small diameter part 102b, and the inner surface of the small diameter part 102b is brought into contact with the outer surface of the inner cylinder 100. The temperature of the uraha in the hydraulic chamber 14 increases due to the increase in pressure, so it is desirable that the cylinder body 8 has a high cooling ability for the oil. However, when the cylinder main body 8 has a 2ffl cylindrical structure as described above, the cooling performance is reduced due to the heat insulating effect of the cavity 104. The above structure in which a part of the outer cylinder 102 is brought into contact with the inner cylinder prevents this reduction in cooling ability, and the oil liquid can sufficiently exchange heat with the outside air from this contact area. This ensures the necessary cooling capacity.

Further, as shown in FIG. 4 and FIG. 6 which is a bottom view of the hydraulic cylinder shown in FIG. 4, the outer cylinder 102 is provided with a discharge portion in which a discharge passage 108a is formed. The passage 106b communicates the cavity 104 with the outside and is usually sealed by a plug member 108c made of a bolt. For example, when this plug member 1one is removed during maintenance, leaked oil accumulated in the cavity 104 can be removed. It is configured so that the liquid can be discharged.

(Effects of the Invention) As explained above, in the suspension according to the present invention, the cylinder body of the hydraulic cylinder has a double cylinder structure consisting of an inner cylinder and an outer cylinder, and the outer cylinder is connected to the rod guide of the cylinder body. Since it is configured as a reserve tank for leaking liquid, even if the working liquid leaks from the rod guide, the leaked liquid will be stored in the outer cylinder, and the leaked liquid will not fall onto the road surface or the outer surface of the cylinder body. There is no risk of problems such as adhesion to the surface.

[Brief explanation of drawings]

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 is a rear view showing a specific example of the hydraulic cylinder and gas spring of the suspension device shown in FIGS. 1 and 2; FIG. 4 is a sectional view of the hydraulic cylinder shown in FIG. 3; and FIG. is a sectional view taken along line V-V in FIG. 4, and FIG. 6 is a bottom view of the hydraulic cylinder in FIG. 4. 2...Car body 4...Wheel 6...
・Hydraulic cylinder 8...Cylinder body 100・
...Inner cylinder 102...Outer cylinder 10
0b...Rod guide Fig. 4 R

Claims (1)

[Scope of Claims] A suspension device comprising a hydraulic cylinder disposed between a vehicle body and a wheel and supporting the vehicle body load by hydraulic pressure within the hydraulic cylinder, wherein the cylinder body of the hydraulic cylinder is cylindrical. 1. A suspension device for a vehicle, characterized in that it has a double cylinder structure consisting of an outer cylinder, and the outer cylinder is configured as a reserve tank for liquid leakage from a rod guide.