JPS63263119A - Vehicle hydraulic supply device - Google Patents

Abstract

PURPOSE:To eliminate energy loss in a hydraulic pump by providing a second control valve for feeding a line pressure to a first control valve in accordance with the hydraulic pressure of the hydraulic pump, and by controlling the line pressure fed from the second control valve in accordance with the running condition on of a vehicle. CONSTITUTION:An attitude variation restraining and controlling circuit 21 delivers instructions for restraining variations in the attitude of a vehicle in accordance with lateral accelerations, vertical accelerations and longitudinal accelerations which are detected by sensors 22 through 24. Then, a pressure control valve 10 which is a first control valve connected to a first output side pipe line 8 from a hydraulic pump 3 driven by an engine 1, controls the control pressure of a pressure chamber 15a in a hydraulic cylinder 15 constituting a hydraulic suspension. Meanwhile a controller 26 serving as a line pressure control means controls a a variable orifice valve 25 which is a second control valve connected between the first output side pipe line 8 and the suction side pipe line 5 in accordance with lateral accelerations detected by the sensor 22. Thereby the line pressure fed to the pressure control valve 10 is controlled.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides a hydraulic cylinder between the vehicle body and each wheel, and controls the pressure in the pressure chamber of the hydraulic cylinder to control the roll of the vehicle. The present invention relates to an improvement in a vehicle hydraulic pressure supply device that supplies control pressure to a hydraulic cylinder in a vehicle having a hydraulic suspension that controls characteristics such as pitch and bounce.

[Prior Art] As a conventional vehicle hydraulic pressure supply system, one having the configuration shown in FIG. 7, for example, is known.

This conventional device has a hydraulic pump 3 connected to the output shaft 2 of the engine 1.
is directly connected to the hydraulic pump 3, and a relief valve 43 is connected to the output side of the hydraulic pump 3 to maintain the output pressure below a set pressure.

[Problem that the invention seeks to solve]

However, in such a conventional vehicle hydraulic supply system, one hydraulic pump 3 is connected to the output shaft 2 of the engine l.
In addition, regardless of the engine speed, the load on the hydraulic supply system, that is, the load on the hydraulic supply system is supplied from the first control valve to the hydraulic cylinders interposed between the vehicle body and each wheel. Regardless of the control pressure, a predetermined inline pressure is always ensured, and the line pressure is higher than the maximum control pressure of the first control valve.
Therefore, the loss of horsepower consumed by the hydraulic pump is large, and the load on the engine is also large, resulting in poor fuel efficiency and an excessive rise in oil temperature due to relief.

This invention was made by focusing on these conventional problems, and eliminates the loss of horsepower consumed by the hydraulic pump, reduces the load on the engine, improves fuel efficiency, and also reduces the rise in oil temperature due to relief. It is an object of the present invention to provide a hydraulic pressure supply device for a vehicle that is made smaller.

[Means for solving problems]

Therefore, the vehicle hydraulic pressure supply device of the present invention is a hydraulic pressure supply device that supplies line pressure to a first control valve, and based on the line pressure, the pressure is applied between the first control valve and the vehicle body and each wheel. A hydraulic pressure supply system for a vehicle that supplies control pressure to a hydraulic cylinder installed in a hydraulic cylinder includes a hydraulic pump and a first control valve that supplies line pressure to a first control valve based on hydraulic pressure discharged from the hydraulic pump. The present invention is characterized by comprising two control valves and a line pressure control means for controlling the line pressure output from the second control valve in accordance with vehicle running state information.

[Effect]

The hydraulic pressure discharged from the hydraulic pump is converted into line pressure by a first control valve controlled by a line pressure control means and supplied to a second control valve, and the line pressure is converted into a control pressure by the second control valve. The oil is converted into hydraulic fluid and supplied to hydraulic cylinders interposed between the vehicle body and each wheel, and the vehicle's characteristics such as roll, pitch, and bounce are controlled.

At this time, the line pressure of the first control valve is controlled according to the driving state information of the vehicle, so there is no loss of horsepower consumed by the hydraulic pump, the load on the engine is reduced, and fuel efficiency is improved. Also, the rise in oil temperature due to relief is reduced.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration of the first embodiment will be explained.

In FIG. 1, l is an engine as a rotational drive source, 2
3 is a hydraulic pump connected to the output shaft 2, and this hydraulic pump 3 has a constant flow control valve 4 built therein. 5 is a suction side tube, and this suction side tube 5 is connected to a strainer 7 in a tank 6.

The constant flow rate control valve 4 returns the remainder of the amount exceeding the predetermined discharge amount to the suction side pipe 5 when the engine speed increases and the discharge amount of the hydraulic pump 3 exceeds a predetermined value.

8 is a first output side pipe which is a discharge side pipe of the hydraulic pump 3, and this first output side pipe 8 is connected to a pressure boat 28 of a pressure control valve 10 which is a first control valve via a check valve 9.
The pressure oil connected to the output pipe 8 and flowing through the first output pipe 8 has a line pressure P, and this line pressure P3 can be measured by the pressure gauge 11.

Further, the return port 28C of the pressure control valve 10 is connected to the tank 6 via the piping 12. Further, between the vehicle body 13 and the wheels 14, a cylinder tube 15a and a piston 15 are provided.
The pressure chamber 15 is composed of the piston rod 15C and the piston rod 15C.
A hydraulic cylinder 15 having a diameter d is interposed to constitute a hydraulic suspension.
It is connected to the pressure chamber 15d of No. 5. And this second
The pressure oil flowing through the output side piping 16 has a control pressure P controlled by the pressure control valve 10, and this control pressure Pc can be measured by the pressure gauge 17.

18 is a coil spring, 19 is a throttle valve, and 20 is an accumulator. The throttle valve 19 and the accumulator 20 apply a damping force to the vertical vibration of the wheel 14 at a frequency higher than the unsprung resonance frequency. 14 suppresses flapping.

21 is an attitude change suppression control circuit for suppressing changes in vehicle body attitude, and this attitude change suppression control circuit 21 includes lateral acceleration sensors 22 . A command value E for suppressing changes in vehicle body posture is supplied to the proportional solenoid 32 of the pressure control valve 10 based on signals such as lateral acceleration, vertical acceleration 5 and longitudinal acceleration of the vehicle detected by the vertical acceleration sensor 23 and the longitudinal acceleration sensor 24.

A variable throttle valve 25, which is a second control valve, is connected between the first output pipe 8 and the suction pipe 5, and the variable throttle valve 25 is connected to the lateral acceleration sensor 22 via a controller 26.
The line pressure P is adjusted based on the lateral acceleration value, which is information on the running state of the vehicle detected by the line pressure P.

FIG. 2 shows details of the pressure control valve 10.

In the figure, the pressure control valve 10 includes a cylindrical valve housing 28, a spool 29 and a rod 30 slidably disposed in an insertion hole 28a provided in the valve housing 28,
A spring 31 interposed between the spools 29 and 07130, and a proportional solenoid that controls the pressing force of the spring 31 via the rod 30 to control the movement of the spool 29 between the offset position and the operating positions at both ends thereof. 32
and has. Here, the valve housing 28 includes a pressure boat 28b, each of which has one end communicating with the insertion hole 28a and the other end connected to the first output side piping 8 of the hydraulic supply device.
A return boat 28c connected to the hydraulic supply device via piping 12, and an output port 2 communicating with the pressure chamber 15d of the hydraulic cylinder 15 via the second output side piping 16.
8d is provided. Drain passages 28e and 28f communicating between the return port 28c and the upper and lower ends of the spool 29 are communicated with the return port 28c.

The spool 29 also includes a land 29a facing the pressure boat 28b and a land 29 facing the return boat 28c.
9b is formed, and both lands 29a, 29
A land 29C having a smaller diameter than b is formed at the lower end, and a pressure control chamber is formed between the land 29a and the land 29C. This pressure control chamber has a pilot passage of 28 g.
It is connected to the output port 28d via.

Further, the proportional solenoid 32 includes an actuator 32a that is slidable in the axial direction and an excitation coil 32b that drives the actuator 32a, and the command value E from the attitude change suppression control circuit 21 described above is supplied to the excitation coil 32b. ing.

In this pressure control valve 10, a pressing force from a proportional solenoid 32 is applied to a spool 29 via a spring 31. Then, in a state where the pressing force of the spring 31 and the pressure in the pressure control chamber are balanced, the wheel 14 is vibrated with a relatively low frequency corresponding to the sprung mass resonance frequency range of the upward vehicle caused by passing a convex part on the road surface. When an input (or a downward vibration input due to passage through the recess) is transmitted, the piston rod 15C of the hydraulic cylinder 15 tends to move upward (or downward), and the pressure in the pressure chamber 15d increases (
or decrease).

In this way, when the pressure in the pressure chamber 15d increases (or decreases), the pressure chamber 15d and the second output pipe 1
6. The pressure in the pressure control chamber communicated through the output port 28d and the pilot passage 28g increases (or decreases), and the balance with the pressing force of the spring 31 is lost, so the spool 29 moves upward (or downward). Move and pressure boat 28
b and the output port 28d changes in the closing direction (or opening direction), so a part of the pressure in the pressure chamber 15d is transferred from the output port 28d to the return port 28C and the piping 1.
2 to the tank 6 (or hydraulic pressure is supplied from the hydraulic pressure supply device to the pressure chamber 15d via the pressure port 28b, the output port 28d, and the second output side piping 16).

As a result, the pressure in the pressure chamber 15d of the hydraulic cylinder 15 is reduced (or increased), and the upward vibration input causes the pressure in the pressure chamber 15d to decrease (or increase).
5d pressure increase (or pressure chamber 1 due to downward vibration input)
5d pressure decrease) is suppressed, and the vibration input transmitted to the vehicle body 13 can be reduced.

FIG. 3 shows the relationship between the command value E from the posture change suppression control circuit 21 and the control pressure P output from the output port 28d of the pressure control valve 10. When the command value E is O, the control pressure PC is a predetermined offset pressure P. C, and E=0
Before and after, the control pressure Pc increases or decreases with a predetermined proportional gain with respect to the command value E, and becomes saturated when it reaches the rated pressures P and S of the line pressure of the hydraulic pressure supply device.

Here, in order to keep the vehicle body flat regardless of the lateral, vertical, and longitudinal accelerations that act on the vehicle,
A control pressure P as shown in Fig. 4 is required for each acceleration. Acceleration is approximately 0.5 G, vertical acceleration is approximately 0.
1~0.2G.

The lateral acceleration is about IG. Note that PM is a neutral pressure in a stationary state where no acceleration acts on the vehicle body.

That is, normally, the maximum pressure for controlling the attitude of the vehicle body against lateral acceleration so as not to roll is the largest, and is relatively small in the vertical and longitudinal directions. Therefore, the control pressure P is determined mainly depending on the lateral acceleration.

Therefore, focusing on this point, as shown in Fig. 2, for the control pressure PC (broken line) that changes in response to the lateral acceleration,
The line pressure ps (solid line) is supplied from the variable throttle valve 25 to the pressure boat 28b of the pressure control valve 10 by adding the approximately maximum pressure (PI PM) required for posture control when vertical and longitudinal accelerations are applied. Set as . That is, the controller 26 controls the variable throttle valve 25 so that the line pressure P is set as indicated by the solid line in FIG. 5, according to the lateral acceleration detected by the lateral acceleration sensor 22.

Specifically, the value P Csmx of the control pressure P when the lateral acceleration is maximum is approximately 100 kg/cal,
On the other hand, the values of P and -PM are approximately 20 kg/cnl.

Next, the operation of the first embodiment will be explained.

The attitude change suppression control circuit 21 generates command values for suppressing changes in the attitude of the vehicle body based on detection signals such as lateral acceleration, vertical acceleration, and longitudinal acceleration of the vehicle from the lateral acceleration sensor 22, vertical acceleration sensor 23, longitudinal acceleration sensor 24, etc. Outputs E.

In response to this command value E, the pressure control valve 10 controls the control pressure p in the pressure chamber 15d of the hydraulic cylinder 15, as shown in FIG.
Control c. Therefore, this control pressure P is controlled according to the lateral acceleration G as shown by the broken line in FIG.

On the other hand, the variable throttle valve 25 is adjusted via the controller 26 based on the lateral acceleration detection signal from the lateral acceleration sensor 22, and the pressure boat 28 of the pressure control valve 10 is thereby adjusted.
The line pressure P supplied to b is controlled as shown by the solid line in FIG.

That is, the control pressure PC increases as the lateral acceleration increases, and the line pressure P3 increases by adding almost the maximum pressure (
The pressure is the sum of P + PM).

Therefore, when traveling almost straight without applying lateral acceleration, the line pressure P can be set to p, (<p□X), and the loss of horsepower consumed by the hydraulic pump 3 can be eliminated.
In addition, during rolls where lateral acceleration is applied, the line pressure P increases to ensure the necessary control pressure P, and posture changes are reliably suppressed when vertical or longitudinal acceleration is applied. The pressure P3 is controlled to a necessary and sufficient pressure depending on the driving state of the vehicle by adding the minimum necessary pressure to the control pressure P.

Next, a second embodiment will be explained.

First, the configuration will be explained. In FIG. 6, the same components as those in the first embodiment shown in FIG.

In the figure, the second embodiment uses a four-way throttle valve 34 and a steering wheel 35 in place of the variable throttle valve 25 as the second control valve and the controller 26 as line pressure control means in the first embodiment. Preferably, the four-way throttle valve 34 is one that is used for a hydraulic power steering device.

That is, the four-way throttle valve 34 is inserted into the first output side piping 8 of the hydraulic pump 3, and the pressure oil supplied to the pressure chamber of the hydraulic cylinder of the power steering device (not shown) is taken out, and the pressure oil is passed through the check valves 36 and 37. The line pressure P is connected to the pressure boat 28b of the pressure control valve 10. and,
The four-way throttle valve 34 is throttle-controlled by the steering wheel 35, so the line pressure ps is controlled according to the steering torque input to the steering wheel 35, and the steering torque is approximately proportional to the lateral acceleration acting on the vehicle body. ing.

Other configurations may be the same as those of the first embodiment.

The operation of the second embodiment is such that when the driver inputs a steering torque by steering the steering wheel 35, the vehicle turns and lateral acceleration acts on the vehicle body, and the vehicle body attempts to roll. The line pressure ps is controlled in accordance with the steering torque by the four-way throttle valve 34, which is throttle-controlled in accordance with the steering torque.Since this steering torque is approximately proportional to the lateral acceleration, the line pressure P, As in the case of the first embodiment, it is controlled as shown by the solid line in FIG. 5, and the same effect as in the case of the first embodiment is achieved.

In this second embodiment, the steering wheel 35
In order to directly mechanically drive the four-way throttle valve 34,
This has the advantage of further improving stability and reliability as a hydraulic system.

In addition, in the first embodiment described above, as shown in FIG.
Although the line pressure P is controlled by adjusting the variable throttle valve 25 according to the lateral acceleration value detected by the lateral acceleration sensor 22, the steering torque detected by the steering torque sensor 39 instead of the lateral acceleration sensor 22 is shown. Values may also be used.

Since this steering torque value is approximately proportional to the lateral acceleration, it can be regarded as an estimated value of the lateral acceleration.

Also, instead of the lateral acceleration sensor 22, a steering angle sensor 40
Using the steering angle value θ detected by the vehicle speed sensor 41 and the vehicle speed value V detected by the vehicle speed sensor 41, the lateral acceleration value=AV2θ/(1+
BV2) (where A and B are constants), the lateral acceleration value may be estimated.

Furthermore, instead of using the lateral acceleration sensor 22, the command value E of the posture change suppression control circuit 21, which has the largest component corresponding to the lateral acceleration value, may be used as the estimated value of the lateral acceleration.

Further, the first control valve is not limited to the illustrated pressure control valve, and other flow control type servo valves or the like may be applied.

Further, as the second control valve, a pressure control type valve similar to the pressure control valve 10 may be used instead of the variable throttle valve 25.

Further, the line pressure may be feedback-controlled using the line positive value P detected by the pressure gauge 11 as the second control valve.

Furthermore, the variable throttle valve 25 may be built into the hydraulic pump 3.

[Effects of the Invention] As explained above, the vehicle hydraulic supply device of the present invention is a hydraulic pressure supply device that supplies line pressure to a first control valve, and controls the first control based on the line pressure. In a vehicle hydraulic supply system that supplies control pressure from a valve to a hydraulic cylinder interposed between a vehicle body and each wheel, a hydraulic pump and a first hydraulic pressure pump based on the hydraulic pressure discharged from the hydraulic pump are provided. a second control valve that supplies line pressure to the control valve;
Since the configuration is characterized by comprising a line pressure control means for controlling the line pressure discharged from the second control valve in accordance with information on the running state of the vehicle, there is no loss of horsepower consumed by the hydraulic pump. , the load on the engine is reduced, fuel efficiency is improved, oil temperature rise due to relief is reduced, the performance of the hydraulic system is stabilized, and reliability is improved.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a first embodiment of the vehicle hydraulic pressure supply system of the present invention, Fig. 2 is a sectional view showing details of the pressure control valve shown in Fig. 1, and Fig. 3 is a command for the posture change suppression control circuit. Figure 4 shows the relationship between various accelerations acting on the vehicle and the control pressure of the pressure control valve. Figure 5 shows the relationship between lateral acceleration, control pressure, and line pressure. FIG. 6 is a system diagram of the second embodiment, and FIG. 7 is a system diagram of an example of a conventional vehicle hydraulic pressure supply system. 1... Engine, 3... Hydraulic pump, 8... First
Output side piping, 10...pressure control valve, 13...vehicle body, 14...wheels, 15...hydraulic cylinder, I6...
- Second output side piping, 21... Attitude change suppression control circuit, 22... Lateral acceleration sensor, 23... Vertical acceleration sensor, 24... Longitudinal acceleration sensor, 25... Variable throttle valve, 26... Controller, 34... Four-way throttle valve, 35... Steering wheel, 39... Steering torque sensor, 40... Steering angle sensor, 41... Vehicle speed sensor.

Claims (2)

[Claims] (1) A hydraulic supply device that supplies line pressure to a first control valve, the first control valve controlling the hydraulic cylinders interposed between the vehicle body and each wheel based on the line pressure. A hydraulic pressure supply device for a vehicle configured to supply pressure, comprising: a hydraulic pump; a second control valve that supplies the line pressure to the first control valve based on the hydraulic pressure discharged from the hydraulic pump; A hydraulic pressure supply device for a vehicle, comprising: line pressure control means for controlling the line pressure output from the second control valve according to running state information of the vehicle. (2) The hydraulic pressure supply system for a vehicle according to claim 1, wherein the vehicle running state information is information on lateral acceleration acting on the vehicle or information on estimation of the lateral acceleration.