JPS61278468A - Power steering device - Google Patents

Abstract

PURPOSE:To secure such a steering reaction as being optimum to a car driving condition, by controlling a pressure control valve, controlling pressure acting on a hydraulic reaction chamber, in a way of relying on a car speed alone at less than a medium speed range, and at the time of a high speed range, relying on the car speed and a steering angle either. CONSTITUTION:A control valve, which installs hydraulic reaction chambers 5 and 6 at both end sides of the spool 2 installed inside a valve housing 1 and having both these chambers 5 and 6 interconnected via an interconnecting passage 9, controls a feed direction to a power cylinder (unillustrated herein) for discharge pressure of a pump P as the spool 2 is selected according to the rocking direction when a rocking lever 11 is rocked by operation of a steering wheel, and assists its steering power. At the time of selection of the spool 2, pressure acting on these hydraulic reaction chambers 5 and 6 is controlled by a pressure control valve D, but this pressure control valve D is made to be controlled according to output of a car speed sensor 28 at less than a medium speed range and at a high-speed range, according to each output of the car speed sensor 28 and a steering angle sensor 29, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a power steering device that can obtain optimal steering force depending on the driving conditions of the vehicle.

(Prior Art) A device that has been known in the past as this type of device always controls a pressure control valve depending on the vehicle speed and steering angle, regardless of the vehicle speed. It was designed to provide a steering reaction force that corresponds to the driving conditions.

In other words, the controller connected to the pressure control valve detects the vehicle speed and steering angle of the vehicle, and controls the pressure control valve according to these detection signals to control the pressure in the hydraulic reaction chamber of the control valve. I was doing it.

(Problems to be Solved by the Present Invention) In the conventional device as described above, the steering reaction force is controlled depending on the steering angle even in the low speed range and the medium speed range. When turning the steering wheel significantly at low speeds, there is a problem in that the detection of the steering angle is delayed, resulting in poor responsiveness, making it difficult to obtain the desired steering force.

This invention controls the steering reaction force depending only on the vehicle speed in the medium speed range and below, and controls the steering reaction force depending on both the vehicle speed and the steering angle in the high speed range, thereby reducing the weight that depends on the steering angle. The purpose is to provide less equipment.

(Means for Solving Problems) In order to achieve the above object, the present invention provides a control cylinder that controls a power cylinder according to a switching position of a spool that is switched in relation to a steering operation, and a control cylinder that controls a power cylinder in accordance with a switching position of a spool that is switched in relation to a steering operation, At the same time, there is a hydraulic reaction force chamber that applies a reaction force to the spool using this pressure, a pressure control valve that controls the pressure acting on this hydraulic reaction force chamber, and a pressure control valve that controls the pressure depending on the vehicle speed and steering angle of the vehicle. In a power steering device equipped with a controller for controlling a control valve, the pressure control valve is controlled depending only on the vehicle speed in the medium speed range or below, while it is controlled depending on the vehicle speed and the steering angle in the high speed range. The structure is such that the pressure control valve is controlled by

(Operation of the present invention) Since the present invention is configured as described above, in the medium speed range and below, the steering reaction force is controlled depending only on the vehicle speed, and in the high speed range, the steering reaction force is controlled depending on the vehicle speed and the steering angle. Steering reaction force is controlled.

(Effects of the Present Invention) According to the device of the present invention, the responsiveness is not impaired even if the steering wheel is turned sharply below the medium speed range.

Further, in a high speed range, the steering reaction force is controlled depending on the steering angle signal as well as the vehicle speed signal, so that a steering reaction force suitable for the driving conditions of the vehicle can be obtained.

Furthermore, in the high speed range, the steering wheel cannot be turned significantly, so even if the steering reaction force is controlled depending on the steering angle as described above, the responsiveness may be impaired as seen in the medium speed range and below. On the contrary, it becomes possible to perform control according to the driving conditions of the vehicle.

(Embodiment of the present invention) The control valve (2) shown in Fig. 1.2 has spring receivers 3 and 4 in contact with both ends of a spool 2 housed in a valve housing l, and the spring receivers 3 and 4 are in contact with each other. Hydraulic reaction chambers 5, 6
I'm making it happen.

The hydraulic reaction chamber 5.6 has a centering spring 7.
8, and these reaction force chambers 5, 6 are communicated with each other via a communication path 9.

The spool 2 constructed as described above has a pin hole 10 formed therein, and a pin portion 12 formed at the tip of the swing lever 11 is inserted into this pin hole 10. The swinging lever 11 thus constructed swings around the fulcrum 13. A hole 15 is formed in the circular portion 14 formed between the pin portion 12 and the fulcrum 13, and a pinion is inserted into the hole 15. Axis IB is inserted. - The pinion shaft 18 swings when the handle is rotated, and the swing lever 11 also swings about the fulcrum 13 accordingly.

The structure for swinging the swing lever 11 together with the pinion shaft 16 when the handle is rotated is the same as that conventionally known. , Therefore, when the swing lever 11 swings as described above,
For example, the spool 2 is switched depending on the direction of its swinging.
Assuming that the pin portion 12 of the swing lever 11 rotates to the left in the drawing, the spool 2 is switched against the centering spring 7.

When the spool 2 is switched in this way, the supply channel 17 connected to the pump P is connected to the annular 1i111 formed on the spool 2.
8, and the other chamber of the power cylinder S communicates with the tank T via a tank flow path 19.

Therefore, the power cylinder S is supplied from the pump P and is driven by the action of the pressurized oil to power-assist the steering force.Furthermore, when the spool 2 is switched to the opposite side from the above, The power cylinder S will move in the opposite direction.

Then, when turning the handle to switch spool 2,
The pressure within the hydraulic reaction force chambers 5 and 6 acts as a steering reaction force, and the mechanism for controlling this reaction force is as follows.

That is, the communication path 9 includes the fixed throttle 20 and the annular groove 18.
It is constantly in communication with the pump P via the supply channel 17, and is also communicated with the primary port 22 of the pressure control valve D via the port 21.

The pressure control valve has a secondary port 24 in its main body 23.
This secondary port 24 is connected to the tank flow path 19. And the above primary side port 22
A throttle hole 25 is formed in the flow process between the secondary port 24 and the secondary port 24, and a control rod 28 is opposed to the throttle hole 25. The movement stroke of the control rod 2B is controlled according to the amount of current applied to the solenoid 27. The throttle resistance is controlled according to the distance between the control rod 26 and the throttle hole 25, or the amount of thrust of the control rod 26 into the throttle hole 25.

The controller C controls the amount of current supplied to the solenoid 27 of the pressure control valve as described above.

The controller C inputs signals from a vehicle speed sensor 28 provided on the wheel axle or drive shaft of the wheel, and a steering angle sensor 28 provided on the steering shaft,
A predetermined output signal is output accordingly. The signal output from this controller C is transmitted to the solenoid 27.

The amount of current applied to the solenoid 27 is controlled in accordance with this signal.

As shown in FIG. 3, as the amount of current applied to the solenoid 27 increases, the pressure in the hydraulic reaction force chambers 5 and 6 decreases, and as the amount of current applied decreases, the pressure in these reaction force chambers increases. That's what I do.

Therefore, the throttle resistance of the pressure control valve is controlled by the output signal from the controller C, and the pressure in the hydraulic reaction chambers 5 and 6 is also controlled according to the throttle resistance, but the vehicle is stopped. At this time, the bore hole 25 is fully opened, and the pressure in the hydraulic reaction chambers 5 and 6 is brought to approximately the tank pressure.

Therefore, even if load pressure occurs in the power cylinder S,
Since the pressure within the hydraulic reaction chamber 5.6 does not rise, the handle operation becomes easier.

As shown in FIG. 4, as the vehicle speed increases from Vl to vn, the power cylinder S
As well as reducing the output of ;j.

As shown in FIG. 5, the pressure of the power cylinder S relative to the input torque is reduced so that the steering reaction force increases as the vehicle speed increases.

In this way, in the low speed range and medium speed range, the steering reaction force is controlled depending only on the vehicle speed signal as described above.

However, within a certain steering angle range at high speeds.

The amount of current supplied to the solenoid is controlled according to the steering angle signal. That is, in a predetermined steering angle range in a high speed range, the steering reaction force is controlled depending on the vehicle speed and steering angle of the vehicle.

The reason why the steering angle signal is input only in the high speed range as described above is that the steering wheel is not turned significantly in this high speed range.

In other words, if the pressure in the hydraulic reaction chamber 5.6 is controlled depending on the steering angle in the low speed range where the steering wheel may be turned significantly, the response will be poor when the steering wheel is operated quickly, but in the high speed range This is because there is no need to make large cuts, so there is no loss of responsiveness.

Furthermore, if the steering reaction force is controlled depending on both the vehicle speed and the steering angle, the steering reaction force can be obtained in accordance with the driving conditions of the vehicle.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a block diagram, FIG. 2 is a circuit diagram showing a part of it in cross section, and FIGS. 3 to 6 are diagrams showing the steering characteristics. . ■...Control valve, 2...Spool, 5.6...
Hydraulic reaction force chamber, S...power cylinder, D...pressure control valve, C...controller.

Claims (1)

[Claims] a control valve that controls a power cylinder according to a switching position of a spool that switches in relation to steering operation;
A hydraulic reaction force chamber to which the required pressure is transmitted and which applies a reaction force to the spool using this pressure, a pressure control valve that controls the pressure acting on this hydraulic reaction force chamber, and the vehicle speed and steering angle of the vehicle. In a power steering device equipped with a controller that controls the pressure control valve depending on the vehicle speed, in the medium speed range or below, the pressure control valve is controlled only depending on the vehicle speed, while in the high speed range, the pressure control valve is controlled depending on the vehicle speed and the steering angle. A power steering device configured to control a pressure control valve depending on the pressure.