JP2631360B2 - Servo valve control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to two valve control parts which are arranged coaxially and rotatable relative to each other via a torsion bar provided between an input side and an output side of a torque transmission section. At least one end of the torsion bar is resiliently connected, and at least one end of the torsion bar is frictionally connected to a valve control portion corresponding to the end directly or via a portion that is non-rotatably connected to the end. In particular, the present invention relates to a control device for a servo valve of a power steering device of an automobile.

[0002]

2. Description of the Related Art Servo valves of hydraulically assisted power steering systems of motor vehicles are often configured as rotary slide valves, with the rotary valve body being mounted for rotation in a concentric valve bush. ing. This rotational movement takes place against the resistance of the torsion bar which attempts to return the rotary valve body and the valve bush to an intermediate position. The rotary valve body and the valve bush form two parts of a steering column, one of which is operatively connected to the steering handle so as not to rotate relative to the other, and the other part of which is the input end of the steering gear, e.g. It is power-coupled to the pinion so as not to rotate relative to it. The hydraulic servomotor controlled by the rotary slide valve is in each case a rotational movement between the rotary valve body and the valve bush in response to the torque of the hand force to be applied to the steering handle during the steering operation. A servo force which assists the steering operation can be generated in a manner known in principle.

When the torsion bar cannot be elastically loaded, it is important that the rotary valve body and the valve bush accurately assume the intermediate position of the hydraulic pressure, and the servomotor does not generate a servo force at the intermediate position. .

In a typical power steering system, a rotary valve body or a valve bush is firstly connected to one end of a torsion bar or a portion fixedly provided thereto so as not to rotate relatively. Then the other end of the torsion bar or the other part at the part fixedly connected thereto is adjusted and subsequently fixed by pinning, with one or more pins being set after the adjustment. One or more holes must be formed.

[0005] DE-A-4227 A1
The same can be said in principle in the structure according to the specification of Japanese Patent No. 41. There, the area having serrations at one end of the torsion bar is axially pushed into the axial bore of one of the valve controls while forming a first press fit. Thus, the torsion bar is frictionally connected to the valve control. The other end of the torsion bar is provided with an area having a diameter that is slightly larger than the axial bore of the other valve control section that fits this end. This thickened area at the other end of the torsion bar is pushed into the axial bore of the corresponding valve control part, the inner wall of which is permanently deformed while forming a second pressure fit.

If an error occurs when the torsion rod is fixed to the valve control portion in the above-described structure, the entire servo valve becomes a worthless defective product.

[0007]

The problem to be solved by the present invention is as follows.
The new construction simplifies manufacture and adjustment.

[0008]

According to the present invention, there is provided a valve control device which overcomes friction by causing friction due to elastic deformation of portions which are frictionally connected to each other. Rotationally adjustable with respect to the end of the torsion bar corresponding to the part.

[0009]

According to the invention, the valve control part ensures that the torsion rod or the part fixedly connected thereto has a sufficiently high friction to lock the respective adjustment during the operation of the servo valve. It is connected by a strong tightening which allows it to be adjusted after assembly because of its elasticity. The present invention therefore has the advantage that not only rejects due to incorrect adjustments are prevented, but also a great deal of freedom with regard to the timing of the adjustments during the manufacturing process.

[0010]

According to a preferred embodiment of the invention, the interaction between the outer peripheral area of the inner part and the inner peripheral area of the outer part concentric with the inner part produces friction, so that both peripheral surfaces Since the cross section of the area is configured in a spiral with a slight slope facing each other, the relative rotation of both parts
The desired elastic clamping is performed and sufficient friction is maintained for the function of the servo valve during the subsequent rotational movement for adjustment.

[0011] Since the rotational movement during the adjustment is a slight angle,
The reliability of the clamping connection is maintained indefinitely.

Due to the good concentricity of both valve control parts,
On each of the two peripheral surfaces, three spiral-shaped peripheral regions are provided equidistant from one another.

For preferred features of the invention, reference is made to the dependent claims and the following description of the illustrated embodiments.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Servo valve 1 configured as a rotary slide valve
Consists essentially of a stationary housing 2, a valve bush 3 rotatably provided therein and a rotary valve body 4 as another valve control part concentrically provided in the valve bush 3. The rotary valve body 4 is a valve bush 3
Within a limited range. Further, the valve bush 3 and the rotary valve body 4 are connected to each other via a torsion bar 5 which intends to hold the rotary valve body 4 in the valve bush 3 at an intermediate position.

In the case of an example of a power steering device for a motor vehicle, the rotary valve body 4 is operatively connected to a steering handle via a steering shaft (not shown), and the valve bush 3 is an input side of the steering gear device, for example, a pinion 6 of a rack steering device (not shown).
Are connected so as not to rotate relative to each other.

Depending on the degree of torque to be transmitted (between the steering wheel and the steering gear), the valve bush 3
A displacement with respect to the intermediate position occurs between the rotary valve element 4 and the rotary valve element 4, so that the control edge 7 formed on the rotary valve element 4 and the valve bush 3 relatively moves. As a result, if the inlet connection 9 of the servo valve 1 is connected to a hydraulic pressure source 10, generally a pump, and the outlet connection 11 of the servo valve 1 is connected to a relatively pressure-free hydraulic sump 12, A pressure difference occurs between the two motor connections 8 of the servo valve 1 in one direction or the other. Such devices are known in principle.

When the torsion bar 5 is not elastically loaded in either direction of rotation or in the other direction of rotation, there is a so-called hydraulic intermediate position between the valve bush 3 and the rotary valve body 4. It is important that, when the torsion stress of the torsion bar 5 is removed, no hydraulic pressure difference occurs between the motor connections 8.

Adjustment is very simple due to the structure according to the invention. In the illustrated example, both ends of the torsion bar 5 have a non-circular cross-section and the rotary valve body 4 and the pinion 6 have receiving portions of the same non-circular cross-section.
The rotary valve body 4 and the pinion 6 are connected to the corresponding ends of the torsion bar 5 at any rotational positions so as not to rotate relative to each other. Connection by pinning is also possible.

The valve bush 3 is provided so as to be adjustable with respect to the main body of the pinion 6. For this purpose, according to FIG. 2, the body of the pinion 6 is separated from one another by a step-shaped transition and is formed into three peripheral sections 1 each formed slightly spirally.
It has a so-called 3K contour with three. In the embodiment shown in FIG. 2, the radius of each circumferential section 13 increases in the circumferential direction facing counterclockwise, the slope of which is in the range of 1/200. Since the valve bush 3 has an opposing inner peripheral area with a peripheral area 14, when the valve bush 3 is turned a specific amount counterclockwise with respect to the pinion 6, the body of the pinion 6 and the valve bush 3 And a strong self-restraining tightening or wedging is performed.

This tightening or wedging is maintained with sufficient friction when a certain rotational movement of the valve bushing relative to the body of the pinion 6 takes place within the range of adjustment. Re-adjustment can be performed if necessary.

In principle, the connection between the rotary valve body 4 and the corresponding end of the torsion bar 5 or a portion provided so as not to rotate relative to this end is made by connecting the body of the pinion 6 and the valve bush 3. This can be done in the same way. In such a device, the connection between the valve bush 3 and the pinion 6 can be performed without any relative rotation.

Since the interacting peripheral areas 13 and 14 are provided on the valve bush 3 which is relatively large in the radial direction from the body of the pinion 6 and the pinion axis, the area between the peripheral areas 13 and 14 The arrangement shown is advantageous in that relatively small torques can be tolerated between the pinion 6 and the valve bush 3 without fear of inadvertent adjustment even at low surface pressures. Due to the low surface pressure, only a resilient deformation of the body of the pinion 6 or of the valve bush 3 occurs in the area 4 of the peripheral sections 13 and 14 so that the friction present during the adjustment is reduced after a long operating time or after readjustment. It is kept sufficiently unchanged afterwards.

[Brief description of the drawings]

FIG. 1 is a sectional view along an axis of a servo valve configured as a rotary slide valve.

FIG. 2 is a sectional view taken along section line II-II in FIG.

[Explanation of symbols]

 1 Servo valve 3, 4 Valve control part (valve bushing, rotary slide valve) 5 Torsion rod 6 Pinion

Continuation of the front page (56) References JP-A-58-124802 (JP, A) JP-A-48-17131 (JP, A) JP-A-48-24190 (JP, A) Jpn. , U) JP 37-11321 (JP, B1)

Claims (5)

(57) [Claims] 1. A coaxially mounted and relatively rotatable 2
The two valve control parts are torsionally connected to each other via a torsion bar provided between the input side and the output side of the torque transmission section, and at least one end of the torsion bar is connected to this end. Frictionally connected to the corresponding valve control part directly or via a part which is non-rotatably connected to this end, wherein friction is generated by elastic deformation of the parts frictionally connected to each other; Control device for a servo valve, characterized in that the valve control part (3 or 4) overcomes friction and is rotationally adjustable with respect to the end of the torsion bar (5) corresponding to the valve control part. 2. The swirling outer peripheral area of the adjustable valve control part (3) and the corresponding end of the torsion bar (5) or the part (6) connected to this end in a non-rotating manner. Control device according to claim 1, characterized in that the control device (13) and the inner peripheral area (14) interact by friction. 3. Each of three spiral peripheral areas or three.
2. The control device according to claim 1, wherein the multiple peripheral areas (13, 14) are provided at regular intervals in the circumferential direction. 3. 4. The control device according to claim 2, wherein the gradient of the spiral-shaped peripheral area has a value in the range of 1/200. 5. The control device as claimed in claim 1, wherein friction occurs between the valve bush (3) of the rotary slide valve and the axial section of the pinion (6). .