KR0122141Y1 - Mechanical spring regulated by fluid means - Google Patents

Abstract

The present invention relates to an active suspension device having a hydraulic cylinder installed between each wheel and the vehicle body and a pressure control valve for adjusting the working hydraulic pressure supplied from the hydraulic supply device to the hydraulic cylinder. When controlling the attitude of the vehicle body such as rolls and other fittings, and when passing through uneven roads, the pressure control valve is controlled when the vibration is input at a relatively low frequency corresponding to the vehicle resonance frequency from the wheel side. The present invention relates to an active suspension device for a vehicle in which a flow path between a hydraulic cylinder and a sub accumulator is closed by installing an on / off valve between the sub accumulators to reduce the flow rate of the present device and improve an operation response.

Description

Vehicle Active Suspension System

1 is a hydraulic circuit diagram showing a conventional embodiment.

2 is a hydraulic circuit diagram showing an embodiment of the present invention.

3 is a cross-sectional view of the pressure control valve applied to the present invention.

4 is a characteristic diagram according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: hydraulic pump 2: engine

5: Supply piping 10: Return piping

11: Pressure holding part 13: Hydraulic cylinder

21a: Input port 21b: Return port

21c: control port 25: accumulator

The present invention relates to an active suspension device having a hydraulic cylinder installed between each wheel and the body and a pressure control valve for adjusting the working hydraulic pressure supplied from the hydraulic supply device to the hydraulic cylinder. Control of the pressure control valve at the time of controlling the attitude of the vehicle body such as the roll, the other fittings, and the uneven road, and the vibration input at the relatively low frequency corresponding to the body resonance frequency from the wheel side. The present invention relates to an active suspension device for a vehicle in which an on / off valve is installed between accumulators to close a flow path between a hydraulic cylinder and a sub-accumulator to reduce the flow rate of the device and improve the operation response.

In the conventional conventional active suspension device for a vehicle, as shown in FIG. 1, the hydraulic pressure is supplied to the hydraulic cylinder 42 and the hydraulic cylinder 42 installed between each wheel 40 and the vehicle body 41, and the driving force of the engine By a predetermined command value, and a pressure control valve 44 for controlling the hydraulic pressure of each hydraulic cylinder 42 by a predetermined command value, and the detection value of the acceleration sensor 45 provided in the vehicle body 41. Basically, the control device 46 which controls the posture change, the supply pipe 47 and the return pipe 48 which directly connect between the pressure control valve 44 and the hydraulic supply device 43, and the supply pipe 47 The main accumulator 49 for pulsating hydraulic absorption connected to the hydraulic cylinder 42 and the sub accumulator 50 are connected to each other via a damping valve 51.

Therefore, the conventional apparatus as described above controls the movement state of the vehicle by supplying and discharging the oil discharged from the hydraulic pressure supply device 43 to the cylinder of the hydraulic cylinder 42 disposed corresponding to each wheel. A pressure control valve 44, which is a proportional solenoid valve, is disposed in a flow path from the hydraulic pressure supply device to the hydraulic cylinder 42, and the hydraulic pressure of the hydraulic cylinder 42 is supplied and discharged by the control valve 44.

For example, the control outputs IFR and IFL of the control device 46 calculated on the basis of the detection output of the posture change detector 45 are supplied to and discharged from the proportional solenoid of the hydraulic control valve 44 to supply the hydraulic cylinder 42. The vehicle posture control is possible by adjusting the pressure inside.

The concrete constitution of the pressure control valve 44 is shown in FIG. 3, in the valve housing 21 in which the input port 22a, the return port 22b, and the control port 22c are formed. (23), Plaza 24a of the proportional solenoid 24 is arrange | positioned coaxially in order. The spool 22 has lands 22a and lands 22b at both ends thereof. The pressure chamber 22c is formed between the land 22a and the simple wall 21d having the fluid inlet 21c formed in the valve housing 21. A pressure chamber 22d is formed between the land 22b and the valve housing 21. The pressure chamber 22c communicates with the input port 21a through the pilot passage 21e. The pressure chamber 22d communicates with the control port 21c through the fluid passage 22e formed in the spool 22. Reference numerals 22f and 22g denote springs for centering the spool 22. One of the poppets 23 is opposed to a valve seat 12h formed in the simple wall 21g between the pilot flow passage 21e and the return flow passage 21f communicating with the return port 21b. The other side is opposed to the operator 24b of the flanza 24a of the electromagnetic proportional solenoid 24. The proportional solenoid 24 is a planar 24a freely moving in the axial direction, an operator 24b fixed to the planar 24a in the poppet direction, and a coil 24c that axially thrusts the planar 24a. Has The coil 24c generates an appropriate magnetic force from the attitude control device in accordance with the command current value I. Accordingly, thrust is applied in the axial direction to the planar 24a, and the position of the poppet described above is determined through the operator 24b to determine the flow rate passing through the valve seat 21h. While the thrust poppet 24 is constantly applied by the proportional solenoid 24, the inputs of both of the pressure chambers 22c and 22d are kept in the same state. In the spool 22, the control port 21c, the input port 21a, and the return port 21a are shut off from each other in a neutral position. Therefore, the relationship between the command value I and the control pressure Pc output to the control port 21c outputs the flow rate of the pressure Pmin when the command value I is 0 as shown in FIG. When the command value I increases, the control pressure Pc increases with a predetermined proportional coefficient K and is output.

50 and 51 are damping valves and sub-accumulators provided in the hydraulic cylinder 42 to absorb vibrations of the under-spring mass of the high frequency component input from the road surface. The active suspension device cannot control the disturbance of the high frequency component from the road due to the control response.

Therefore, in order to generate the basic damping force even in such an uncontrollable area, the conventional active suspension device has a damping valve 50 and a sub-accumulator (a) in the hydraulic cylinder 42 in order to absorb the vibration of the unsprung mass of the high frequency component input from the road surface. 51) is installed. However, the damping valve 50 and the sub-accumulator 51 control the attitude of the vehicle body such as squat during acceleration, dive during deceleration, roll when turning, and pitching other than that. When passing through the city and uneven road, it controls the pressure control valve when the vibration input of the relatively low frequency corresponding to the body resonance frequency from the wheel side is operated to control the ride comfort, which increases the flow rate of the active suspension control device and also the response characteristics. It has a problem of lowering the active control area by lowering it.

The present invention compensates for the above-mentioned conventional problems, and corresponds to the body resonance frequency from the wheel side during the attitude control of the vehicle body during acceleration, deceleration, rolling roll, and other fittings, and when passing through uneven roads. Controlling the pressure control valve when relatively low frequency vibration is input to control the ride comfort, install an on / off valve between the hydraulic cylinder and the sub accumulator to close the flow path between the hydraulic cylinder and the sub accumulator to reduce the flow rate of the device And as the purpose to be able to improve the operation response, the present invention will be described in detail by the accompanying drawings as follows.

In the structure of the active suspension device of the present invention, as shown in FIG. 2 and FIG. 3, the hydraulic cylinder 19 provided between each wheel and the vehicle body and the hydraulic cylinder 19 are supplied with operating hydraulic pressure and applied to the driving force of the engine. By means of a hydraulic pressure supply device (FS) operated by the pressure control unit, a pressure control valve 13 which controls the hydraulic pressure of the hydraulic cylinders 19 by a predetermined command value, and the detection value of the acceleration sensor installed in the vehicle body. A control device 17 for controlling, a supply pipe 5 and a return pipe 10 for directly connecting between the pressure control valve 13 and the hydraulic supply device FS, and the supply pipe 5 The main accumulator 25 for pulsating hydraulic absorption is connected, and the hydraulic cylinder 19 and the sub accumulator 25 are connected through a damping valve.

In addition, it is configured by connecting the on / off valve 28 between the hydraulic cylinder 19 and the sub accumulator 25.

In addition, the pressure control valve 13 has a spool 22, a poppet 23, and a proportional solenoid 24 in a valve housing 21 having an input port 22a, a return port 22b, and a control port 22c. Planar 24 of is connected to coaxially in order.

The spool 22 also has lands 22a and 22b at both ends.

The pressure chamber 22c is formed between the land 22a and the simple wall 21d having the fluid inlet 21c formed in the valve housing 21.

In addition, a pressure chamber 22d is formed between the land 22b and the valve housing 21, and the pressure chamber 22c communicates with the input port 21a through the pilot passage 21e.

In addition, the pressure chamber 22d communicates with the control port 21c through the fluid passage 22e formed in the spool 22.

Further, 22f and 22g are springs for centering the spool 22.

Further, reference numerals 26 and 27 are damping valves and sub-accumulators for absorbing pressure variations in the hydraulic cylinders by wheel vibrations from the road surface of high frequency components input to the hydraulic cylinders 19.

Reference numeral 28 denotes an on / off valve capable of opening and closing a flow path between the hydraulic cylinder and the sub accumulator.

Referring to the effect of the embodiment of the present invention is configured as described above are as follows.

According to the present invention, an on / off valve is connected in series with a damping valve between a hydraulic cylinder and a sub accumulator to operate the on / off valve to open and close a flow path between the hydraulic cylinder and the sub accumulator.

For example, when vibration is input at a relatively low frequency corresponding to the vehicle body resonance frequency from the wheel side during the posture control of the vehicle body during acceleration, deceleration, rolling roll, pitching, etc. and passing through uneven roads. By controlling the pressure control valve of the valve, the on / off valve is turned off during the ride comfort control to block the flow path between the hydraulic cylinder and the sub-accumulator, thereby improving the response time of the control pressure formation of the hydraulic cylinder and reducing the consumption flow rate of the apparatus of the present invention. On the other hand, when the vehicle runs on the highway at high speed, high frequency vibration is input from the road surface.

Therefore, a device capable of absorbing the road vibration of the high frequency component is not necessary because the device of the present invention can not actively control the road vibration of the high frequency component.

In addition, a sub-accumulator and a damping valve are attached to a hydraulic cylinder to absorb road vibrations of high frequency components in a conventional active suspension device, so that the riding comfort of the vehicle is enhanced by absorbing high frequency vibration input from the road surface. By turning on the off-valve, the flow paths of the hydraulic cylinder and the sub-accumulator can be opened to enable the conventional functions of road surface vibration absorption.

The present invention, as shown in Figure 1 (FS) has a hydraulic pump (1) as a hydraulic supply device, the rotary shaft of the hydraulic pump (1) is connected to the output shaft (2a) of the engine (2) is rotationally driven The suction side is connected to the oil tank 3, and the discharge shaft is connected to the supply pipe 5 through the check valve 4.

In addition, the hydraulic pressure supply device FS includes a pulsation absorption accumulator 6 connected to the supply pipe 5, a filter 6 inserted into the supply pipe 5 downstream of the accumulator 6, and the filter. The check valve 8 connected in parallel with (6) and the return pipe 10 connected to the oil tank 3 through the oil cooler 9 are comprised.

Here, the supply pipe 5 and the return pipe 10 are connected to the supply port 21a and the return port 21b of the pressure control valve 13 corresponding to each wheel through the pressure holding unit 11. .

In addition, the pressure holding unit 11 includes a relief valve 15 into which a check valve 14 inserted into a line pipe is inserted between the line pipe 5 and the return pipe 10 and sets the line pressure PL in a normal state. A pilot operated check valve 16 in which the line pressure downstream of the check valve 14 is operated at a pilot pressure Pp is provided.

In addition, the pilot operated check valve 16 is opened when the pilot pressure Pp is greater than the neutral pressure Pn of the pressure control valve 13, thereby connecting the input port 16i and the output port 16o, When the pilot pressure Pp is smaller than the neutral pressure Pn of the pressure control valve 13, the input port 16i and the output port 16 are shut off.

In addition, the pressure control valve 13 receives the command value I from the attitude change suppression control device 17 which outputs a command value for controlling the attitude change of the vehicle on the basis of detection signals such as the vehicle lateral acceleration, the vertical acceleration, and the front and rear acceleration. And outputs a control pressure Pc corresponding to the command value I, which is supplied to a hydraulic cylinder 19 provided between each wheel and the vehicle body to generate a corresponding force corresponding to the change in attitude of the vehicle body.

In addition, the proportional solenoid 24 has a planar 24a freely moving in the axial direction, an operator 24b fixed to the planar in the poppet direction and a coil 24c for axially thrusting the planar 24a. . The coil 24c generates an electromagnetic force in accordance with the command current value I from the posture change suppressing control device 17.

Accordingly, thrust is applied to the planar 24a in the axial direction, and the position of the poppet described above is determined through the operator 24b to determine the flow rate passing through the valve seat 21h.

In addition, while the output is uniformly applied to the poppet 23 by the proportional solenoid 24, the inputs of both the pressure chambers 22c and 22d are kept in the same state.

In the spool 22, the control port 21c, the input port 21a, and the return port 21b are blocked from each other at a neutral position.

Therefore, as shown in Fig. 3, the relationship between the command value I and the control pressure Pc output from the control port 21c shows that the command value I outputs '0' one-min Pmin, and when the command value I increases in this state, a predetermined proportional coefficient K is obtained. And the control pressure Pc is increased and output.

Then, the input port 21a of the pressure control valve 13 and the pilot check valve 14 of the pressure holding unit 11 are connected, and the return port 21b is a pilot check valve of the pressure holding unit 11 ( 16) is connected to the input port 16i.

The control port 21c is connected to the pressure chamber 19a of the hydraulic cylinder 19 mounted between the vehicle body and the wheels. On the other hand, a pulsating pressure damping gas-filled accumulator 25 is connected to the supply pipe 5 between the pressure holding unit 11, the pressure control valve 13, and the pressure control valve 13.

Therefore, in the present invention, when the vehicle is stopped and the ignition switch is turned off, the rotation of the engine 2 is stopped, and the hydraulic pump 1 is also stopped. At this time, the pressure at the output side of the line pressure holding unit 11 is substantially maintained at the neutral pressure Pn of the pressure control valve 13.

When the switch is turned on, the engine 2 is started to enter the idling state. As the rotation of the output side 2a rises, the rotation of the hydraulic pump 1 also increases, and the hydraulic oil of the discharge amount is supplied to the supply pipe 5 according to this rotation. Supplied.

As a result, the pressure in the supply pipe 5 increases, and the pilot pressure Pp supplied to the pilot check valve 16 also increases.

When the pilot pressure Pp exceeds the relief pilot pressure Ppo, that is, the pressure Pn, the pilot check valve is opened so that the return port 21b of the pressure control valve communicates with the oil tank 3.

Thereafter, the pressure of the working oil discharged from the hydraulic pump 1 is increased so that the line pressure P1 on the upstream side of the check valve 14 exceeds the set pressure P1 of the relief valve 15, and this excess amount is the relief valve 15. Return to the oil tank (3) through the return pipe (10) through.

On the other hand, when the switch is in the on state, the posture change suppressing device 17 is also in an operating state, and a command signal I for suppressing the posture change of the vehicle due to the height change according to the ride of the driver and the occupant is applied to the pressure control valve. It outputs to match the garage to the target garage. When this height adjustment is performed, the fluctuation of the line pressure is small and maintained at approximately the set pressure PLh.

Subsequently, as the vehicle starts, the pressure change control device detects the attitude change of the vehicle body such as the dives during acceleration, the swivel deceleration during the acceleration, the roll during the turning, and the pitching of other parts. Output to the valve controls the pressure of the hydraulic cylinder and the attitude change of the vehicle body.

In addition, when passing through the uneven road, when a relatively low frequency vibration input corresponding to the body resonance frequency is transmitted from the wheel side to the hydraulic cylinder, the internal pressure of the hydraulic cylinder is changed according to the vibration input, and the pressure of the control port of the pressure control valve is changed. do.

In this state, the pressure in the pressure chamber of the pressure control valve is also changed. When the pressure in the pressure chamber is lower than the pressure in the pressure chamber formed by the command signal (I) of the posture change suppressor, the spool moves to the downstream side to output the port. And control port communicate with each other to supply the line pressure to the hydraulic cylinder.

As a result, the internal pressure of the hydraulic cylinder increases, and the input port 21a is closed by the land 22b at the point where the pressure chamber 22c and the pressure chamber 22d move upstream, and the pressure is equal to the pressure chamber 22c.

If the pressure in the pressure chamber 22d is higher than the pressure chamber 22c, the spool 22 moves upstream, whereby the return port 21b and the control port 21c are connected, and the hydraulic oil in the hydraulic cylinder 19 returns to the return pipe 10. Is stored in the oil tank (3).

For this reason, the pressure in the hydraulic cylinder 19 falls, and accordingly, the pressure in the hydraulic chamber 22c also falls, and the spool 22 moves downstream. In this way, the return port 22b is closed by the land 22a at the point where the pressure of the pressure chamber 22c and the pressure chamber 22d becomes equal. As a result, the pressure from the road surface transmitted to the hydraulic cylinder 19 is prevented from being absorbed and transmitted to the vehicle body.

In addition, when the road surface input of the high frequency component of the natural frequency of a wheel is transmitted to the hydraulic cylinder 19 from the wheel side, the pressure change of the pressure chamber 19a of the hydraulic cylinder 19 arises according to this vibration input, but in this case, The pressure change of the pressure chamber 19a is absorbed by the sub accumulator 7 via the damping valve 26.

Therefore, if the ignition switch is turned off while the vehicle is stopped in the running state, the hydraulic pump 1 of the hydraulic supply device FS stops rotating in accordance with the rotation stop of the engine 2 and the pump discharge pressure drops sharply, but the supply piping Since the check valves 4 and 14 are inserted in (5), the pressure is gradually reduced through the pilot passage 21e and the return passage 21f of the pressure control valve 13.

In addition, as shown in FIG. 4, when the pressure of the accumulator 25 becomes less than the neutral pressure Pn, the pilot check valve 16 is closed, so that the pressure in the pressure control valve 13 and the hydraulic cylinder 19 is reduced. Encapsulation is maintained at a neutral pressure Pn.

As described above, the active suspension device according to the present invention is connected to the on / off valve 28 in series with the damping valve 26 between the hydraulic cylinder 19 and the sub accumulator 27, and this on / off By operating the valve 28, the flow path between the hydraulic cylinder 19 and the sub accumulator 27 can be opened and closed.

Therefore, the pressure when the vibration is input at a relatively low frequency corresponding to the body resonance frequency from the wheel side during the attitude control of the vehicle body such as the squat at the time of acceleration, the dive at the time of deceleration, the roll at the time of turning, and other pitching. The control valve is controlled to turn off the on / off valve to control the ride comfort, thereby blocking the flow path between the hydraulic cylinder and the sub-accumulator, thereby improving the response time of the control pressure formation of the hydraulic cylinder and reducing the consumption flow rate of the device.

On the other hand, when the vehicle travels at high speed at high speed, high frequency vibration is input from the road surface. Therefore, at high speeds, the present invention requires a device capable of actively absorbing road vibrations of high frequency components due to the inability to actively control road vibrations of high frequency components. In the conventional active suspension system, a sub-accumulator and a damping valve are attached to the hydraulic cylinder to absorb road vibrations of high frequency components. In the ride comfort control to absorb the high frequency vibration input from the road surface to improve the ride comfort of the vehicle, the on / off valve is turned on to obtain the effect of absorbing road surface vibration by opening the flow paths of the hydraulic cylinder and the sub accumulator.

Claims (1)

Of the hydraulic cylinder 19 provided between each wheel and the vehicle body, a hydraulic supply device FS that supplies hydraulic pressure to the hydraulic cylinder 19 and is operated by the driving force of the engine 2, of the hydraulic cylinders 19 A pressure control valve 13 for controlling the working oil pressure by a predetermined command value, a control device 17 for controlling posture change based on the detected value of the acceleration sensor installed in the vehicle body, the pressure control valve 13 and the hydraulic supply device ( A vehicle having a supply pipe (5) and a return pipe (10) for direct connection between FSs, comprising: a pulsating hydraulic absorption main accumulator (25) connected to the supply pipe (5); 19 and the sub accumulator 2 are connected via a damping valve 26, an on / off valve connected in series with the damping valve 26 between the hydraulic cylinder 19 and the sub accumulator 27 ( 28) an active suspension for a vehicle, comprising: .