KR0137236B1 - Power steering device - Google Patents

Abstract

According to the present invention, the torsion bar of the power steering device of the power steering device can improve the operating force of the steering wheel by automatically adjusting the torsional force of the torsion bar according to the traveling speed in the power steering device of the automobile. It relates to a torsional stress control device.

The present invention provides a cylinder chamber directly above the hydraulic chamber between the torsion bar and the rotary valve mounted on the existing steering housing, and is equipped with a piston that is elastically supported by the spring between the hydraulic chamber and the cylinder chamber, the high return hydraulic pressure during low-speed driving By moving the piston upward, the return hydraulic pressure is applied to the upper part of the torsion bar located in the cylinder chamber so that the steering wheel can be lightly operated.In high speed driving, the weak return hydraulic pressure enters the cylinder chamber and the piston By lowering the effective torsion length of the torsion bar, the steering wheel's maneuvering force is increased so that the steering wheel's operating force can be improved according to the driving speed and the stability of steering wheel's operation at high speed is improved.

Description

Torsional stress regulator of torsion bar of power steering

1 and 2 are cross-sectional views of an operating state of a steering apparatus for explaining the present invention.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a cross-sectional view showing a torsion bar steering operation state of the device of the present invention.

※ Explanation of code for main part of drawing

1: steering housing 2: steering spindle

3: torsion bar 4: spline

5: pinion shaft 6: pinion

7: rack 10: input port

11: Return port 13: Rotary valve

14: supply port 15: recovery port

16: Input shaft 17: Cylinder chamber

18: spring 19: piston

20: hydraulic chamber

The present invention is to improve the operating force of the steering wheel (aka: steering wheel) to contribute to safe driving by automatically adjusting the effective length of the torsion bar according to the traveling speed in the power steering device of the vehicle. It relates to a torsional stress control device acting on the torsion bar of the power steering system.

In general, automobiles with heavy loads on the steering axle, such as luxury cars, heavy trucks and all-wheel drive vehicles, require a large steering force to steer the wheels, and thus employ a power steering device to solve this problem.

And since there are many types of power steering devices, there are some differences in configuration depending on the type, but the torsion bar, steering gear device, hydraulic pump device, hydraulic control device, which is usually connected to the steering column device, one or two It is composed of an operation piston device and a traveling speed sensor, so that the steering force of the steering wheel can be automatically adjusted according to the driving speed of the vehicle. For example, the automatic control of the steering wheel's operating force is low. When the driving speed is low, the steering wheel's operating force (force of steering wheel) decreases. On the contrary, when the driving speed is high, the steering wheel's operating force decreases. By making it larger, you can drive safer driving.

As a conventional steering device for satisfying the steering force as described above in the form of the example shown in Figs. 1 and 2, a relatively large space is provided on the lower portion B of the torsion bar, indicated by a virtual line, and a control valve is provided. A suction groove was formed in the control valve to adjust the amount of return hydraulic pressure flowing through the suction groove according to the rotation angle of the torsion bar.

That is, in the conventional art, as the torsion bar is rotated, the suction groove of the control valve is opened so that the return hydraulic pressure flows into the reaction force plunger of the hydraulic reaction chamber so that the torsion bar corresponds to the reaction force according to the change in the angle of the torsion bar. It is designed to impart resistance, which means that the reaction force plunger has a high return hydraulic pressure (at high speeds) or less pressure (low speeds).

However, the conventional steering device as described above has a problem in that the steering column housing is enlarged because a relatively large space must be secured in order to install a control valve at the bottom of the torsion bar, and this problem increases the steering force by increasing the weight of the steering device. It caused a backing defect.

Accordingly, the inventors of the present invention have devised a power steering apparatus that can more effectively improve steering power by eliminating the drawbacks that hinder steering force improvement as described above and by using a member that automatically adjusts the torsion bar torsional stress.

The present invention is to adjust the torsional stress of the torsion bar automatically according to the traveling speed by mounting a separate piston at the top of the torsion bar in the existing power steering device, and by providing a hydraulic chamber that can move the piston up and down In order to improve the operating force of the steering wheel, the following will be described in detail with reference to the accompanying drawings, the members of the steering apparatus as required by the present invention.

1 and 2 is a cross-sectional view showing the internal structure of the steering housing equipped with the main body of the present invention and the operating state of the main body, the steering housing (1) has a steering spindle (2) connected to the steering shaft The torsion bar 3 is mounted, and the lower spline 4 of the torsion bar 3 is connected to the pinion shaft 5.

The pinion 6 of the pinion shaft 5 is engaged with the rack 7.

In addition, the steering housing 1 is provided with a pressure port 10 for receiving hydraulic pressure from an oil pump, a return port 11 for returning hydraulic pressure to an oil tank, and a rotary valve 13 that is supplied to the pressure port 10. Supply port 14 for sending the hydraulic pressure passing through the operating cylinder and the recovery port 15 for recovering the hydraulic pressure returned through the operating cylinder, respectively, the return hydraulic pressure recovered to the recovery port 15 is It is configured to influence the torsional stress of the torsion bar by changing the position of the piston 19 by acting hydraulic pressure to the cylinder chamber 17 while flowing into the rotary valve (13).

In the existing power steering apparatus configured as described above, the cylinder chamber 17 is formed inside the input shaft 16 surrounding the upper end of the torsion bar 3, and the spring 18 is formed in the cylinder chamber 17. The piston 19, which is elastically installed, is configured to be capable of lifting up and down while being engaged with the spline 3a of the torsion bar 3, and the piston 19 is twisted by the torsion bar 3. By changing the effective length, the steering wheel's operating force is improved.

Moreover, the constant of the spring 18 which elastically supports the piston 19 of the said cylinder chamber 17 is related with return hydraulic pressure. That is, the return hydraulic pressure is returned closely related to the traveling speed, so the spring constant is also adjusted to the return hydraulic pressure. For example, when the traveling speed is 20 km / h or less, the piston 19 compresses the spring 18 by the pressure of the return hydraulic pressure so that the return hydraulic pressure acting on the piston 19 is greater than the value of the spring 18 constant. In the case of more than 50km / h, the spring 18 constant value was larger than the return hydraulic pressure to prevent the spring 18 from raising the piston 19.

The present invention having such a member can improve the steering force during driving and further improve the stability of the steering wheel when driving at high speed.

First, in the case where the driving speed of the vehicle is a low speed, as mentioned above, since the return hydraulic pressure is high, the hydraulic chamber 20 is recovered between the rotary valve 13 and the torsion bar 3 by the recovery port 15. Return hydraulic pressure is introduced into the pressure greater than the spring (18) constant, the return hydraulic pressure is introduced to the piston 19 before exiting the return port 11, the piston 19 is a spring ( As the piston 19 moves up, the return hydraulic pressure enters the inside of the cylinder chamber 17 while compressing 18). (See Figure 1)

As described above, the length of the torsion bar 3 is extended by the upward movement of the piston 19 to the upward movement distance of the piston 19, thereby increasing the amount of torsion of the torsion bar 3 with respect to the input. Due to the relative movement, the discharge port expands and the discharge flow rate increases, which means that the steering wheel can be lightly rotated.

In contrast to the above, when the vehicle is traveling at a high speed, the hydraulic pressure of the liter is lower than that of the low-speed driving, so the pressure of the return hydraulic pressure that is recovered from the operation cylinder and flows into the hydraulic chamber 20 through the recovery port 15 is a spring ( 18) Since it is smaller than the constant, the piston 19 is lowered to the lower end of the cylinder chamber 17 by the spring force of the spring 18, so that the effective length of torsion of the torsion bar is shortened and the torsional stress of the torsion bar 3 is reduced. This increases the amount of torsion on the input, so that the port is partially open and the discharge flow rate is reduced. Therefore, the assist force is reduced, and a lot of force is required to rotate the steering wheel.

If the steering wheel is made heavy by adjusting the torsional stress of the torsion bar as described above, the steering wheel (handle) is prevented from being operated during high speed driving, and thus, the effect of preventing the fall of the vehicle due to the rapid turning operation during high speed driving is prevented. You can get it.

The present invention as described above forms a cylinder chamber inside the cylinder that securely holds the torsion bar on the upper part of the steering housing, and the piston to reduce or expand the effective torsion length of the torsion bar while moving up and down the torsion bar in the cylinder chamber and the In accordance with the driving speed of the car without the case of increasing the weight of the steering housing by mounting a spring that is elastically supported by a constant value that allows the piston to move in accordance with the driving speed in relation to the return hydraulic pressure introduced into the hydraulic chamber. It is an invention that can provide a sense of stability to the steering force of the steering wheel when driving at high speed by improving the rotational operation force of the steering wheel.

Claims (1)

A torsion bar with steering spindles connected to the steering shaft is mounted, and the lower spline of the torsion bar is connected to the pinion shaft so that the pinion can be engaged with the rack to operate the actuating piston shaft left and right, and between the torsion bar and the rotary valve. In a power steering device comprising a pressure port for supplying hydraulic pressure to the hydraulic chamber of the hydraulic chamber, a return port returned from the hydraulic chamber and a steering housing forming a supply port and a recovery port connected to the hydraulic connection line to the operation cylinder, A piston is mounted in the cylinder chamber, which is inside the cylinder mounted above the hydraulic chamber between the torsion bar and the rotary valve, so that the piston is mounted so that the lifting operation can be performed, and the lifting operation of the piston is related to the return hydraulic pressure. Torsional stress regulating device of the torsion bar of the power steering system characterized in that it has a configuration in which the piston is elastically supported by a control spring.