JPH0717231A - Suspension controller - Google Patents

Abstract

PURPOSE:To provide a suspension controller which can be simplified and the cost of which can be reduced suppressing the number of solenoid valves performing control to supply oil to or drain oil from a cylinder. CONSTITUTION:A pilot type supply and drain oil valve 7 is provided, with its pilot passage 7A connected to a main pipe 3, and a pilot check valve 9, which allows the flow in downstream direction and allows the reverse flow when the pilot pressure reaches a specified value, is interposed to the downstream section of the connection of the pilot passage 7A of the main pipe 3, with its pilot passage 9A connected to the upstream section of itself in the main pipe 3, and a solenoid proportional control valve 12 capable of adjusting the pressure on the side of an inlet 12A is interposed in the middle of a sub pipe 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device used in an automobile.

[0002]

2. Description of the Related Art As a suspension control device of this type, the present applicant has already applied for a device disclosed in Japanese Patent Application No. 4-217211. This suspension control device has a hydraulic cylinder interposed between the axle and the vehicle body, and an electromagnetic oil supply / drain valve provided in a pipe line connecting each hydraulic cylinder and a hydraulic source.
A proportional electromagnetic relief valve is installed in a sub-pipe connecting the oil supply and drain valve to the oil tank in the oil pressure source.The solenoid oil supply and drain valve can be opened and closed. With this, pressure oil is supplied to and discharged from the hydraulic cylinder to adjust the vehicle height.

[0003]

By the way, in the above-mentioned suspension control device, since the electromagnetic type oil supply and drain valve is provided for each wheel, the manifold for incorporating this electromagnetic type oil supply and drain valve becomes large, and the vehicle There is a problem in that the mountability of the device becomes poor and the cost of the entire device becomes high due to the large number of electromagnetic valves.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a suspension control device capable of suppressing the number of solenoid valves of the entire device to simplify the device and thus reduce the cost. To aim.

[0005]

In order to achieve the above object, the present invention provides a suspension control device for adjusting a vehicle height by supplying and discharging oil liquid to and from a cylinder interposed between a vehicle body and each wheel side. A normally-closed pilot type oil supply / drain valve is provided between the cylinder line connected to each of the cylinders and the main line connected to the pump for supplying pressure oil, and the pilot line is connected to the main line. A pilot check valve that is interposed and is located at the downstream side of the connecting portion of the pilot passage of the main pipeline, and allows the flow in the downstream direction and allows the flow in the opposite direction when the pilot pressure reaches a predetermined value. In the middle of the auxiliary pipeline connecting the pilot passage to the upstream portion of the main pipeline to the pilot check valve and branching to the pump side portion of the main pipeline to connect to the reservoir tank. Wherein the pressure of the inlet side is interposed an adjustable electromagnetic proportional pressure control valve.

[0006]

With this configuration, when the pilot type oil supply / exhaust oil valve is closed, the electromagnetic proportional pressure can be obtained so that the pressure in the main pipeline exceeds the opening pressure of the pilot type oil supply / exhaust oil valve. By supplying a current of a predetermined value to the pressure control valve, the pilot type oil supply / exhaust valve is opened, pressure oil from the pump is supplied to each cylinder, and the vehicle height rises. When the oil valve is closed, the valve opening pressure that allows the flow of the pilot check valve in the opposite direction, which is lower than the cylinder pressure as the main line pressure, and the valve opening pressure of the pilot type oil supply / drain valve can be obtained. By supplying a current of a specified value to the electromagnetic proportional pressure control valve, the pilot check valve opens to allow flow in the opposite direction, and the pilot type oil supply / drain valve vehicle height also opens. The oil liquid inside passes through the solenoid proportional pressure control valve. Since the vehicle height is lowered and returned to the reservoir tank Te, the supply and discharge and the vehicle height adjustment associated therewith for each cylinder can be achieved by providing a single electromagnetic proportional pressure control valve.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A suspension controller according to an embodiment of the present invention will be described below with reference to FIGS. In the figure, a pump 2 drivably connected to an engine 1 includes:
One end of the main pipe line 3 is connected to the cylinder 1 and the cylinder pressure P of the left and right front cylinders 5a, 5b and the rear left and right cylinders 5a, 5b, which will be described later, is sucked from the reservoir tank 4 by being driven by the engine 1. _The pressure oil having a higher pressure than that of _C is discharged to the main pipe line 3.

The left and right front cylinders 5a and 5b are
It is interposed between the vehicle body and each wheel side, and it expands and contracts by the supply and discharge of oil liquid to adjust the vehicle height. Front and left cylinder pipes 6a and 6b are connected to the front and left cylinders 5a and 5b, respectively. Although the rear left and right cylinders and the rear left and right cylinder conduits are provided in correspondence with the front left and right cylinders 5a, 5b and the front left and right cylinder conduits 6a, 6b, this illustration is omitted. Along with that, the description is omitted as appropriate.

Between the left and right front side cylinder pipes 6a, 6b and the other end of the main pipe 3, a normally closed 3 port 2 position front pilot type oil supply / drain valve 7 is provided. Cage,
The pilot passage 7A is connected to the main pipeline 3. The pilot type oil supply and drain valve 7 on the front side
A predetermined value (hereinafter referred to as valve opening pressure) at which the internal pressure of the main pipe 3 is lower than the cylinder pressure P _{C of the} front left and right cylinders 5a and 5b and higher than the filled pressure of the front left and right gas springs 8a and 8b. The valve opens at P _R.

A pilot check valve 9 located downstream of the connecting portion of the pilot passage 7A in the main pipeline 3 and allowing a flow in the downstream direction is provided in the pilot passage.
9A is connected to the pilot passage 7A of the pilot type oil supply / drain valve 7 on the front side. The pilot check valve 9 allows the flow in the opposite direction when the internal pressure of the pilot passages 9A, 7A and by extension the main pipe line 3 reaches the valve opening pressure P _R. A sub-pipe 10 is provided to branch to the pump 2 side portion of the main pipe 3 and connect to the reservoir tank 4. An electromagnetic proportional pressure control valve 12 having a solenoid 11 is provided in the middle of the sub-pipe 10, and the solenoid 11
The pressure at the inlet 12A side can be adjusted by changing the current supplied to the valve and adjusting the opening of the internal passage.

The solenoid current of the solenoid proportional pressure control valve 12 and the pressure on the inlet 12A side have a linear characteristic as shown in FIG. 3, and by supplying the solenoid current I _a to the solenoid 11, its inlet 12A side, As a result, the pressure (valve opening pressure) P _R can be obtained as the pressure in the main conduit 3, and the solenoid current I _b is supplied to the solenoid 11 to the inlet 12A side thereof, and as a result, the pressure in the main conduit 3 to the left and right cylinders 5 on the front side.
A pressure P _S higher than the cylinder pressure P _C of a and 5b can be obtained. When the vehicle height is in the normal state of the reference vehicle height, the solenoid proportional pressure control valve 12 does not energize the solenoid 11 (non-energized state) and its inlet 12
The pressure on the A side, and by extension, the main pipeline 3 is set to zero.

The left and right gas springs 8a and 8b on the front side are
The cylinders are connected in parallel to the front left and right cylinders 5a and 5b, and the front left and right damping force adjusting mechanisms 13a,
13b is provided. Further, 14a and 14b are front side left and right vehicle height sensors that detect the vehicle height between the sprung and unsprung portions on the front side left and right sides of the vehicle. The front left and right vehicle height sensors 14a, 14b output signals indicating this when the vehicle height reaches a high level, a normal level or a low level.

A rear side main pipe (main pipe) 3R is provided branching to a portion of the main pipe 3 between the pilot check valve 9 and the pilot type oil supply / drain valve. A rear pilot type oil supply / exhaust valve (not shown) having the same function and structure as the front pilot type oil supply / exhaust valve 7 is provided between the left and right rear side cylinder pipes and the other end of the main pipe 3R. ) Is interposed, and its pilot passage is connected to the same portion (main pipe 3) as the pilot passage 7A of the pilot type oil supply / exhaust valve 7 on the front side.

Rear left and right gas springs (not shown) having the same function and structure as the front left and right gas springs 8a and 8b are provided in parallel with the rear left and right cylinders. Corresponding to the front left and right vehicle height sensors 14a, 14b, rear left and right vehicle height sensors (not shown) for detecting the vehicle height between the unsprung and unsprung portions on the rear side of the vehicle are provided. When the vehicle height of the detection target portion reaches a high level, a normal level or a low level, a signal indicating this is output. Front left and right vehicle height sensors
14a, 14b, rear side left and right vehicle height sensors, front side electromagnetic proportional pressure control valve 12 is connected to a controller 15, and a controller 15 is provided. Front side left and right vehicle height sensors 14a, 14b and rear left and right vehicle height sensors The set pressure of the electromagnetic proportional pressure control valve 12 is adjusted on the basis of the signal from, and the vehicle height is adjusted by controlling the supply and discharge of the oil liquid to the left and right front side cylinders 5a and 5b and the rear left and right cylinders.

The operation of the suspension control device thus configured will be described. In FIG. 2, when the vehicle height is in the normal state of the standard vehicle height, the front pilot type oil supply / exhaust valve 7 and the rear pilot type oil supply / exhaust valve are closed, and the electromagnetic proportional pressure control valve 12 is used. The solenoid 11 is in a non-energized state. When the pump 2 operates in accordance with the rotation of the engine 1 to suck the oil liquid from the reservoir tank 4 and discharge the pressure oil to the main pipe line 3, the pressure oil passes through the electromagnetic proportional pressure control valve 12 and the reservoir tank 4 moves. The normal vehicle height is maintained.

When the vehicle height is increased (from normal to high in FIG. 2), the solenoid current I _{b is changed} to the electromagnetic proportional pressure control valve 12
Supply to the solenoid 11. Then, so that the resulting inlet 12A side of the electromagnetic proportional pressure control valve 12, the pressure P _S in excess of opening pressure P _R as thus pressure main conduit 3. For this reason, the pilot side oil supply / drain valve 7 on the front side and the pilot type oil supply / drain valve on the rear side are opened, and the pressure oil from the pump 2 is applied to the cylinders 5a, 5b on the left and right front sides and the cylinders on the left and right rear sides. It is supplied and the vehicle height rises. At this time, a part of the pressure oil from the pump 2 is returned to the reservoir tank 4 through the electromagnetic proportional pressure control valve 12. In this case, the electromagnetic proportional pressure control valve 12 may be closed so that the pressure oil from the pump 2 is entirely supplied to the front left and right cylinders 5a and 5b and the rear left and right cylinders. By controlling in this manner, the vehicle height increase response becomes excellent. When the vehicle height reaches a high level, the left and right vehicle height sensors 14
The signals a, 14b and the vehicle height sensors on the left and right sides of the rear side output a signal indicating this to the controller 15, and the controller 15 accordingly sets the solenoid current to zero. Then, the pressure at the inlet 12A side of the electromagnetic proportional pressure control valve 12, and hence at the main pipe line 3, becomes zero, and the pilot type oil supply / exhaust valve 7 on the front side and the pilot type oil supply / exhaust valve on the rear side are closed and the high vehicle height is increased. Will be maintained.

When the vehicle height is lowered (from high in FIG. 2 to normal), the solenoid current I _{a is changed} to the electromagnetic proportional pressure control valve 12
Supply to the solenoid 11. Then, the valve opening pressure P _R lower than the cylinder pressure P _C can be obtained as the pressure on the inlet 12A side of the electromagnetic proportional pressure control valve 12, and by extension, on the main pipe line 3.
Therefore, the pilot check valve 9 is opened so as to allow the flow in the opposite direction, and the pilot type oil supply / exhaust valve on the front side is opened and the pilot type oil supply / exhaust valve on the rear side is opened.
Oil liquid in the front left and right cylinders 5a, 5b and in the rear left and right cylinders is returned to the reservoir tank 4 via the electromagnetic proportional pressure control valve 12, and the vehicle height is lowered. When the vehicle height reaches the normal vehicle height, the left and right vehicle height sensors 14a, 14b
The rear left and right vehicle height sensors output a signal indicating this to the controller 15, and accordingly the controller 15 sets the solenoid current to zero. Then, the pressure at the inlet 12A side of the electromagnetic proportional pressure control valve 12, and hence at the main pipe line 3, becomes 0, and the pilot type oil supply / exhaust valve 7 on the front side closes and the pilot type oil supply / exhaust valve on the rear side closes. Will be maintained.

As described above, the supply and discharge to and from the left and right front cylinders 5a and 5b and the rear left and right cylinders and the vehicle height adjustment associated therewith are adjusted to a total of 2 for the vehicle harmonic front side and the rear side, respectively. Since this is achieved by providing two pilot type oil supply / exhaust oil valves, the number of oil supply / exhaust oil valves can be reduced as compared with the case where the above-mentioned conventional technology provided four oil supply / exhaust valves for each wheel. . For this reason, the manifold for installing the pilot type oil supply / drain valve and thus the entire device can be made compact. Further, as the number of parts is reduced, the cost of the device can be reduced. Further, it is not necessary to provide an electric circuit for driving the oil supply / exhaust oil valve, which is required in the prior art, and the device can be made inexpensive by that much.

The opening pressures P _R of the pilot check valve 9, the front pilot type oil supply / exhaust valve 7 and the rear pilot type oil supply / exhaust valve are determined by the gas springs on the left and right front sides.
8a, 8b and the rear side left and right gas springs are set to a higher pressure than the enclosing pressure, which causes zero down of the front left and right gas springs 8a, 8b and rear left and right gas springs, and this zero down Impact can be prevented. Further, in the above embodiment, one pilot type supply / discharge switching valve 7 is provided on each of the front side and the rear side, but the present invention is not limited to this, and it may be provided for each wheel, or a total of one. Good.

[0020]

Since the present invention is the suspension control device configured as described above, one electromagnetic proportional pressure control valve is provided for supply / discharge control for the front left and right cylinders and the rear left and right cylinders. This has been achieved, and the number of oil supply / exhaust oil valves is reduced compared to the prior art in which one solenoid valve is provided for each wheel, for a total of four solenoid valves. Can be made compact. Further, as the number of parts is reduced, the cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a piping system diagram schematically showing a suspension control device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an operation of the suspension control device.

FIG. 3 is a diagram showing characteristics of an electromagnetic proportional pressure control valve used in the suspension control device.

[Explanation of symbols]

 2 Pump 3 Main line 5a, 5b Front side left and right cylinders 6a, 6b Front side left and right cylinder lines 7 Pilot type oil supply and drain valve 7A Pilot type oil supply and drain valve pilot line 9 Pilot check valve 9A Pilot check valve Pilot line 10 Sub-line 12 Electromagnetic proportional pressure control valve 12A Inlet of electromagnetic proportional pressure control valve

Claims (1)

[Claims] 1. A suspension control device for adjusting a vehicle height by supplying / discharging an oil liquid to / from a cylinder interposed between a vehicle body and each wheel side, in a cylinder pipe line and a pressure oil connected to each cylinder. A normally-closed pilot type oil supply / drain valve is installed between the main conduit and the main conduit connected to the pump, and the pilot passage is connected to the main conduit. A pilot check valve which is located at a portion and allows a flow in a downstream direction and a flow in a reverse direction when the pilot pressure reaches a predetermined value, and a pilot check valve in the main pipe, which is upstream from the pilot check valve in the main pipeline. An electromagnetic proportional pressure control valve that can adjust the pressure on the inlet side is installed in the middle of the auxiliary pipeline that branches to the pump side part of the main pipeline and connects to the reservoir tank. A suspension control device characterized in that