JPH0615288Y2 - Pressure control valve for active suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a pressure control valve, and more particularly to a proportional solenoid pressure reducing valve.

[Conventional technology]

As a pressure control valve having the structure of a proportional electromagnetic pressure reducing valve, for example, Japanese Patent Application No. 61-134218 previously proposed by the present applicant is proposed.
No. (Invention title; active suspension).

The pressure control valve includes a three-way spool valve inserted between a hydraulic source and a hydraulic cylinder, and a proportional solenoid that controls the spool position of the three-way spool valve according to a predetermined command value. . Of these, hydraulic oil from a hydraulic source is supplied to the supply port (input port in the previous application) of the three-way spool valve, and the return port (output port in the previous application) is connected to the drain side of the hydraulic source and further output. The port (input / output port in the previous application) is connected to the hydraulic cylinder. This pressure control valve feeds back the control pressure output from the output port to the pressure control chamber of the spool, and balances the pressure based on this feedback pressure with the thrust of the proportional solenoid, and is supplied from the hydraulic power source. The line pressure is reduced according to a predetermined command value, and this is supplied as a control pressure to a hydraulic pressure source.

On the other hand, this pressure control valve has a large flow rate of hydraulic oil from the hydraulic cylinder side when the vehicle passes through a relatively gentle uneven part and the vibration input in the sprung resonance frequency range (about 1 Hz) is in the hydraulic cylinder. Is returned (or supplied) to the hydraulic pressure source side,
This allows the output port and the return port of the spool valve to communicate with each other, returning (or supplying) the hydraulic oil to the hydraulic source to absorb the pressure fluctuation and suppress the vibration transmitted from the road surface side to the vehicle body side. Has become.

[Problems to be solved by the device]

However, in the above-mentioned pressure control valve, the path that connects the output port and the return port is not provided with means for generating the throttling effect on the hydraulic oil flowing through this path, and therefore, as described above. When the vibration input in the sprung resonance frequency range is from the hydraulic cylinder side, a hydraulic power source that can generate a large flow rate is required in order to generate sufficient damping force for this vibration input. There was an unsolved problem of growing.

This invention has been made in view of such an unsolved problem, and when a vibration input of a relatively low frequency accompanied by a large pressure change from the hydraulic cylinder side is present at the output port, the hydraulic power source is made large. It is an object of the present invention to provide a pressure control valve capable of significantly dampening its vibration input without performing the operation.

[Means for Solving the Problems]

To achieve the above object, the present invention comprises a three-way spool valve having a supply port, a return port connected to a fluid pressure source side, and an output port connected to a fluid pressure cylinder of an active suspension. The pilot pressure is supplied to one spool end side of the valve, the control pressure output from the output port is fed back to the other spool end side, and the control pressure is controlled according to the pilot pressure. In the above active suspension pressure control valve, a throttle for generating a large damping force with respect to pressure fluctuation in the sprung resonance frequency range is provided on the output port side.

[Action]

In this invention, when there is a vibration input to the fluid pressure cylinder of the active suspension and the internal pressure of this fluid pressure cylinder increases, the pressure of the output port of the three-way spool valve increases, and accordingly the output port and The return ports communicate with each other, and the working fluid is returned to the fluid pressure source side through the throttle. At this time, when the vibration input to the fluid pressure cylinder is in the sprung resonance frequency range, the pressure fluctuation transmitted to the output port side is greatly attenuated by the throttle and the working fluid returning from the return port to the fluid pressure source side is The flow rate is limited to reduce the change in flow rate on the fluid pressure cylinder side.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. In this embodiment, the pressure control valve according to the present invention is
The case where it is applied to a hydraulic active suspension that performs roll control of a vehicle is shown.

First, the overall configuration of the active suspension will be described with reference to FIG. 2 (the figure shows only one of the hydraulic systems for the four wheels).

In the figure, 10 is an active suspension, 12 is a wheel, 14 is a wheel side member, and 16 is a vehicle body side member.

The active suspension 10 has a predetermined line pressure (for example, 8
(0 kg / cm ² ), a hydraulic pressure source 18 for supplying a hydraulic pressure, and an accumulator 20 installed downstream of the hydraulic pressure source 18 for accumulating pressure.
A pressure control valve 22 provided on the downstream side of the accumulator 20, a hydraulic cylinder 24 interposed between the vehicle body side member 16 and the wheel side member 14, and a cylinder of the vehicle body side member 16 and the hydraulic cylinder 24. The coil spring 30 is provided between the tubes 28a to support the static load of the vehicle body, and the posture change suppressing device 32 that controls the pressure control valve 22 is provided. The posture change suppressing device 32 includes a lateral acceleration sensor 34 that detects a lateral acceleration of the vehicle body, and a controller 36 that controls the pressure control valve 22 based on the lateral acceleration detection signal. Further, the pressure chamber L of the hydraulic cylinder 24, which will be described later, absorbs the vibration in the unsprung resonance frequency range from the road surface side, and the accumulator 4 is provided via the throttle valve 38.
It is connected to 0.

The hydraulic pressure source 18 has a hydraulic pump that operates by using the engine of the vehicle as a rotational drive source and pressurizes and discharges the hydraulic oil in the tank. Based on the discharge pressure of the hydraulic pump, the hydraulic oil having a predetermined line pressure is used. Is output.

As shown in FIG. 1, the pressure control valve 22 is composed of a pilot operated proportional electromagnetic pressure reducing valve, and has a valve mechanism portion 22A including a three-way spool valve and a proportional mechanism for controlling the valve mechanism portion 22A. And a solenoid 22B.

Of these, the valve mechanism portion 22A has a valve housing 42,
An insertion hole 44 is formed in the valve housing 42. A communication hole 4 having a predetermined diameter is provided at a predetermined position of the insertion hole 44.
A partition wall 46 having 6A for varying the pilot pressure is provided laterally in the axial direction, whereby the insertion holes 44 are separated. Among these, a poppet 48 axially biased by the proportional solenoid 22B is slidably disposed in the insertion hole 44 on the proportional solenoid 22B side. This poppet 48 is a plunger 6 of the proportional solenoid 22B, which will be described later.
It is provided to relax the centering accuracy of No. 6. On the other hand, in the insertion hole 44 on the opposite side, the fixed diaphragm 5
0 is laterally provided at a predetermined distance from the partition wall 46, and a pilot chamber PR is formed between the fixed throttle 50 and the partition wall 46. The fixed throttle 50 suppresses the turbulence of the pressure P _P in the pilot chamber PR due to the displacement of the main spool 52, which will be described later. A plurality of them may be provided around the circumference.

Further, the main spool 52 described above is slidably arranged in the insertion hole 44 on the side opposite to the poppet 48 through the fixed throttle 50, and the valve housing 4 is provided.
A supply port 54 s, an output port 54 c, and a return port 54 r, which communicate with the insertion hole 44, are formed in the unit 2.
The supply port 54s is connected to the hydraulic source 1 via the hydraulic pipe.
8 is connected to the hydraulic oil supply side, the return port 54r is connected to the drain side of the hydraulic power source 18 via the hydraulic pipe, and the output port 54c is connected to the pressure chamber of the hydraulic cylinder (actuator) 24 described later via the hydraulic pipe. It is connected to L.

Here, the output port 54c is provided with an orifice throttle Pco that throttles the flow rate of the hydraulic oil flowing through the return port 54r or the supply port 54s. The diameter of the orifice Pco is set to a predetermined value that can generate a large damping force when there is a pressure fluctuation input of around 1 Hz from the hydraulic cylinder 24 side.

A pilot-side pressure control chamber _FU and an output-side pressure control chamber _FL are respectively formed at both axial ends of the insertion hole 44 facing the main spool 52, and the upper and lower ends of the main spool 52 are respectively formed in the pressure control chamber chambers. F _U, respectively arranged offset spring 60U to F _L, which will be described later pressure chamber 52c of the main spool 52 is defined closed state as shown (the offset amount is zero) and so as by 60L.

The main spool 52 has a land 52a facing the supply port 54s, a land 52b facing the return port 54r, an annular groove-shaped pressure chamber 52c formed between the lands 52a and 52b, and the pressure chamber 52c. and feedback passage 52 communicating the output-side pressure control chamber F _L
and d. Feedback passage 52d
As shown in the figure, the orifice Pc for damper is provided in the.

On the other hand, the pilot chamber PR is communicated with the pilot side pressure control chamber F _U through the fixed throttle 50, and communicates with the supply port 54s via a pilot supply passage PP. The poppet 48 side of the insertion hole 44 communicates with the return port 54r through the pilot return passage PT.
Further, both end sides of the poppet 48 in the insertion hole 44 and the pilot return passage PT are connected to each other via a communication passage RR.

Then, the the pilot supply passage PP is provided a multi-stage orifice Qp for regulating the pilot flow rate necessary for forming a pilot pressure P _P, whereas, in the multi-stage orifice Pr is provided in the pilot return path PT There is. Further, the communication passage RR is provided with an orifice Pd for suppressing the disturbance of the pilot pressure P _{P due} to the movement of the poppet 48.

Therefore, the opening area of the communication hole 46A is changed by adjusting the sliding position of the poppet 48, and the supply port 54
s, pilot supply passage PP, pilot chamber PR, communication hole 46A, pilot return passage PT, return port 54r
Hydraulic oil flow flowing through, i.e. pilot pressure P _P in the pilot chamber PR is adjusted, whereby the pressure of the pilot-side pressure control chamber F _U is controlled. Then, both the pressure control chamber F _U, when the pressure F _L are different, the main spool 52 is urged to the pressure difference is reciprocated in the axial direction, adjustment flows or discharge the hydraulic oil in the pressure chamber 52c pressure The operation is performed transiently. Then, when the pressure of the pressure chamber 52c (that is, the control pressure P _C of the output port 54r) and the pilot pressure P _P are balanced, the value of the exciting current I _{S in} the subsequent steady state (when the hydraulic cylinder 24 is in the fixed state). Regardless of this, the spool position of FIG. 1 is always taken, and the control pressure P _C set equal to the pilot pressure P _P is maintained.

Here, the main spool 52 and the three ports 54s, 54
A three-way spool valve is constituted by the valve housing 42 having r and 54c.

On the other hand, the proportional solenoid 22B has a valve housing 42
Of the cylindrical housing 62, a through hole 64 formed at the center of the cylindrical housing 62 and communicating with the through hole 44, and a plunger 66 slidably provided in the axial direction of the through hole 64. And an exciting coil 68 for driving the plunger 66 in its axial direction.
The tip of the actuator 66A of the plunger 66 is the poppet 4 described above.
8 can be contacted. In addition, the plunger 66 has
Communication hole 66 for communicating both ends in the axial direction to allow hydraulic oil to flow back and forth
B is formed.

Then, an exciting current I _S as a command value is supplied to the exciting coil 68 from a posture change suppressing device 32, which will be described later, and is excited. Therefore, the actuator 66A of the plunger 66 is
The poppet 48 is urged downward in FIG. 1 according to the value of the exciting current I _S. Further, when the exciting current I _S is zero, the proportional solenoid 22B is in the non-excited state, and the plunger 66 and the poppet 48 are returned to their initial positions.

Returning to FIG. 2, the hydraulic cylinder 24 has the cylinder tube 24a.
Piston 24c urged by piston rod 24b inside
Is slidable in the axial direction. A pressure chamber L separated by a piston 24c is formed in the cylinder tube 24a on the lower side thereof.

Further, the controller 36 is configured to include a microcomputer, calculates lateral acceleration based on the detection signal of the lateral acceleration sensor 34, and performs calculation such as multiplying this lateral acceleration by a predetermined gain constant, The value of the exciting current I _S as a command value is set within a predetermined range from I _{SMIN to} I _SMAX (see FIG. 3), and the exciting current I _S is supplied to the proportional solenoid 22B.

Next, the operation of the above embodiment will be described.

When the ignition switch is turned on, the posture change suppressing device 32 operates, and the rotation of the engine drives the hydraulic pressure source 18 as described above to supply a predetermined line pressure.

The posture change suppressing device 32 detects the lateral acceleration acting on the vehicle body as described above, and performs a predetermined calculation for setting the command value. As a result, the excitation current I _S is set to a value near the neutral value I _SN during steady traveling such that the vehicle is traveling straight on a good road at a constant speed. I _S is higher than the neutral value I _SN (e.g. outer side)
And a low value (for example, the inner ring side).

Now, suppose that the vehicle performs the above-described steady running and the exciting current I _S is set to its neutral value I _SN . As a result, the proportional solenoid 22B is energized, the plunger 66 biases the poppet 48 with a thrust of a predetermined value, and the flow resistance between the poppet 48 and the communication hole 46A is set to its neutral value. In other words, the pilot pressure P _P is also set to its neutral value, the pressure of the pilot-side pressure control chamber F _U and the output-side pressure control chamber F _L are compared.

At this time, both the pressure control chamber F _U, the pressure of F _L is balanced (i.e., the control pressure P _C, i.e. the pressure and the pilot pressure P _P in the pressure chamber L of the hydraulic cylinder 24 are equal) if to have a,
The position of the main spool 52 continues to be in the closed state shown in FIG. 1 (provided that the hydraulic cylinder 24 is in a fixed state), and the control pressure P _C is also held at the neutral pressure P _CN .

Further, when the pressure in the pilot side pressure control chamber F _U is lower than the pressure in the output side pressure control chamber F _L , that is, when the control pressure P _C is higher than the pilot pressure P _P , the main spool 52 moves to the pilot side pressure control chamber F _U. In the direction (upper side in FIG. 1), the output port 54c and the return port 54r communicate with each other. Therefore, hydraulic fluid is returned to the port 54r side return via the pressure chamber 52c, the pressure of the output-side pressure control chamber F _L decreases. This causes the pressure to drop too much,
Becomes lower than the pressure of the pilot-side pressure control chamber F _U, the main spool 52 is moved to turn the opposite direction (lower side in FIG. 1), the supply port 54s and the output port 54o
Make communication between them. Thereafter, after a transient state in which this cycle is repeated, the pressures in both pressure control chambers F _U and F _L are balanced, the main spool 52 again assumes the closed position in FIG. 1, and the control pressure P _P becomes the neutral pressure P _CN. It will be set within a very short time.

The pressure of the pilot-side pressure control chamber F _U is higher than the pressure of the output-side pressure control chamber F _L, that is, when the control pressure P _C is less than the pilot pressure P _P, changes in contrast to the above, the same tone Pressure is applied.

Further, if the exciting current I _S is increased from the neutral state where the vehicle height value is in the proper range, the pilot pressure P _P is set high accordingly. Therefore, the pressure equilibrium between the two pressure control chambers F _U and F _L is lost again, and the control pressure P _C is changed to the pilot pressure P through the transient state similar to that described above.
It is boosted according to _P , that is, the value of the exciting current I _S. On the other hand, if the exciting current I _S is reduced, the control pressure P _C is reduced accordingly.

Therefore, in the present embodiment, when the change of the control pressure P _C with respect to the change of the exciting current I _S is shown, the static characteristic of FIG. 3 is obtained.
Here, P _CMAX is the maximum control pressure substantially corresponding to the line pressure of the hydraulic power source 18, and P _CMIN is the minimum control pressure.

In this way, in each pressure control valve 22, the control pressure P _C according to the commanded value of the exciting current I _S is supplied to the corresponding hydraulic cylinder 24. Therefore, each hydraulic cylinder 24
In the pressure chamber L of, the biasing force against the roll is individually generated,
Thereby, the roll rigidity is controlled, and the change in the posture of the vehicle body is appropriately suppressed.

On the other hand, now, and in both the pressure control chamber F _U, steady state pressure is balanced in F _L (see spool position of FIG. 1). In this state, it is assumed that the vehicle passes through a relatively gentle uneven road, and a vibration input in the sprung resonance frequency range (about 1 Hz) is input from the road surface side into the pressure chamber L of the hydraulic cylinder 26. This vibration input becomes a pressure fluctuation corresponding to it and is transmitted to the pressure chamber 52c of the pressure control valve 22.

This vibration input, the pressure of the output-side pressure control chamber F _L is a temporary increase (or decrease) higher than the pressure of the pilot-side pressure control chamber F _U becomes (or lower). As the main spool 52 is urged by this, the pressure control chamber F _U
Side (or _{F L} side) moves to the output port 54c and return port (or supply port 54s and the output port 54c)
And the hydraulic oil is temporarily returned to (or supplied to) the hydraulic pressure source 18. The main spool 52 when both the pressure control chamber F _U, the pressure of F _L are balanced again returns to its closed position. In this way, regardless of the value of the exciting current I _S , the pressure change is absorbed, the vibration transmitted from the road surface side to the vehicle body side is significantly suppressed, and the deterioration of the riding comfort is accurately prevented.

Further, when the vibration input from the road surface side has a high frequency corresponding to the unsprung resonance frequency due to the fine unevenness of the road surface, the pressure fluctuation of the pressure chamber L of each hydraulic cylinder 24 passes through the throttle 38. Is transmitted to the accumulator 40. As a result, similarly, the vibration transmissibility to the vehicle body can be significantly reduced.

Here, referring to FIGS. 4 and 5, there are a case where the orifice throttle Pco in the configuration of the present embodiment is added to the output port 54c (see the solid line in the figure) and a case where it is not added (see the dotted line in the figure). The difference will be explained. FIG. 4 shows the change of the damping constant with respect to the vibration (oil pressure fluctuation) frequency from the hydraulic cylinder 24 side, and FIG. 5 shows the change of its phase. According to this, when the orifice diaphragm Pco is added, a large damping constant, that is, a damping force is obtained particularly in the sprung resonance frequency range (1 to 2 Hz) as compared with the case where this is not added. The damping effect is that the orifice throttle returns to port 5
This is larger than the case where it is provided on the vehicle 4r, and the vibration transmitted to the vehicle body is significantly reduced as a whole, and the riding comfort is significantly improved. At this time, the phase tends to be delayed in the sprung resonance frequency range, but as can be seen from the graph, in the high frequency range where the phase delay is considered to be a problem in terms of performance, the phase delay is very small and the orifice throttle Pco Almost the same as when it is not added. Therefore, the orifice diaphragm Pco having a predetermined diameter
The provision of the above does not hinder other performances at all, and according to the present embodiment, it contributes to the improvement of the overall performance including the reduction of the swish noise.

In the above-described embodiment, the case where the pressure control valve of the present invention is applied to the active suspension 10 for a vehicle has been described. This is, for example, a suspension for a ship that supports the cabin to the hull so as to suppress the vibration of the cabin. It may be a device.

Further, in the above-described embodiment, the orifice restrictor Pco is provided at the output port of the pressure control valve 22 itself, but this may be the output port of the control valve sub-plate.

Further, the pressure control valve of the present invention can be applied not only to the hydraulic control valve but also to the pneumatic control valve.

[Effect of device]

As described above, in the present invention, since the throttle for generating a large damping force against the pressure fluctuation in the sprung resonance frequency range is provided on the return port side of the three-way spool valve, the fluid pressure cylinder of the active suspension is provided. There is a vibration input in
When the pressure at the output port increases and the output port and the return port communicate with each other, and the vibration input of the fluid pressure cylinder is in the sprung resonance frequency range, the large pressure transmitted to the output port accordingly. It has an excellent effect that the fluctuation can be largely attenuated by the throttle, and this damping effect can be achieved without making the fluid pressure source large.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, FIG. 2 is a schematic diagram showing an active suspension for a vehicle to which the pressure control valve shown in FIG. 1 is applied, and FIG. 3 is pressure control. A graph showing the static characteristic of the valve exciting current I _S vs. the control pressure P _C , FIG. 4 is a graph showing an example of changes in the damping constant with respect to the vibration frequency from the road surface side, and FIG. 5 is a graph showing the phase with respect to the vibration frequency. It is a graph which shows an example of change. In the figure, 18 is a hydraulic pressure source (fluid pressure source), 22 is a pressure control valve,
22B is a proportional solenoid, 24 is a hydraulic cylinder (actuator), 42 is a valve housing, 46 is a partition wall, 48 is a poppet, 50 is a fixed throttle, 52 is a main spool, 5
4s is a supply port, 54r is a return port, 54c is an output port, and Pco is an orifice throttle.

Claims (1)

[Scope of utility model registration request] 1. A three-way spool valve having a supply port, a return port connected to a fluid pressure source side, and an output port connected to a fluid pressure cylinder of an active suspension, and one spool end of the three-way spool valve. Pressure for the active suspension, which supplies pilot pressure to the spool side and feeds back the control pressure output from the output port to the other spool end side, and controls the control pressure according to the pilot pressure. In the control valve, a pressure control valve for an active suspension characterized in that a throttle for generating a large damping force with respect to a pressure fluctuation in a sprung resonance frequency range is provided on the output port side.