JPS6216133Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in rotary valves used, for example, in power steering devices.

In a typical rotary valve, as shown in Fig. 1, a valve rotor 2 attached to a rotating shaft 1 is formed into a right circular column, and a valve sleeve 3 that slides relative to the circumferential surface of the rotor 2 is also formed in a right circular cylinder shape. has been done.

Therefore, the land portion 4 and the groove portion 5 have no choice but to be made by mechanical cutting, which inevitably complicates the manufacturing process of the valve and makes it quite difficult to reduce production costs.

On the other hand, in order to eliminate mechanical cutting processes as much as possible when processing valve sleeves and rotors, the sliding surfaces of the rotor and sleeve are made into conical surfaces centered on the axis of rotation, and cast, forged or sintered alloys are used. The applicant has proposed a rotary valve that can be integrally molded.

To explain this based on Figures 2 and 3,
The figure shows a control valve of a power steering device, and in the figure 11 is a stub shaft connected to the steering wheel and to which steering input is transmitted;
2 shows a wormshaft to which the output rotation is fed back, a valve rotor 13 is fixed to the stubshaft 11, and a valve sleeve 1 is located outside the wormshaft and connected to the wormshaft 12.
4 are arranged.

Valve sleeve 14 is rotatably supported by valve housing 15.

Then, the valve sleeve 14 and the valve rotor 1
3 is formed into a conical surface centered on the axis of the stub shaft 11, and in this case, the conical diameter increases in the direction of the cover 18.

Land portions 19a, 19b and groove portions 20a, 2 are provided on the outer circumferential conical slope of the valve rotor 13.
0b is formed (FIG. 3), and the groove portion 20
The groove bottoms of a and 20b are formed approximately in the axial direction, so the depth of the groove becomes gradually shallower toward the small diameter portion of the cone, and the extension of the groove bottom intersects with the slope. It is formed like this.

The valve sleeve 14 is constructed in the same manner, and includes port portions 21a and 21 formed on the inner conical surface.
In b, the groove bottom is approximately parallel to the axis, and therefore the groove depth changes continuously in the axial direction.

With this configuration, the valve rotor 13 and the valve sleeve 14 can be integrally formed by forging, precision casting, sintered metal, etc., and the land portions 19a, 19
b. There is no need for any machining of the groove portions 20a, 20b or the port portions 21a, 21b.

By the way, in this rotary valve, the hydraulic oil from the pump port 22 when in neutral state or from the load side 23a, 23b when turning is transferred to the valve rotor 1.
3 and the stub shaft 11 or between the valve rotor 13 and the cover 18.
(Fig. 2), the valve rotor 13 has a groove portion 20b.
and a radial return hole 26 communicating with the passage 24.
It is necessary to provide

Therefore, regarding the valve rotor 13, the groove portions 20a, 20b and the land portions 19a, 1
Although 9b can be integrally formed by casting or sintered alloy, the subsequent machining 4 (drilling) to provide the return hole 26 is unavoidable, which improves workability in manufacturing and shortens working time. The benefits in this respect were not sufficient.

The present invention has been developed with attention to these points, and by providing a return passage for hydraulic oil extending in the axial direction from a predetermined groove portion and opening at the end face of the valve rotor or valve sleeve, mechanical cutting can be achieved. The present invention provides a rotary valve that reduces processing steps as much as possible.

Hereinafter, embodiments of the present invention will be described based on the drawings, and substantially the same parts as in FIGS. 2 and 3 will be designated by the same reference numerals.

As shown in FIGS. 4 and 5, the rotating sliding surface 16 between the valve sleeve 14 and the valve rotor 13A
In the large diameter end of the valve rotor 13A, a groove portion 20b and a passage 24 (tank port 25) are provided.
A return passage 27 is provided substantially along the axial direction to communicate with the.

That is, the return passage 27 is connected to the valve rotor 13.
It is formed to open at the end surface 28 of A.

Note that instead of doing this, the return passage 27 may be provided in the valve sleeve 14, and in this case, the return passage 27 may be provided in the groove portion 20 of the valve rotor 13A in the neutral position.
What is necessary is just to form it in the shape of a groove in the inner circumferential surface facing b, and to open in the end surface 29 of the valve sleeve 14.

In this way, by providing the return passage 27 along the axial direction, when integrally molding the valve sleeve 14 or the valve rotor 13A, it is possible to perform mold cutting in the axial direction without using a split mold, and the valve No further machining is required for the rotor 13A.

Further, the return passage 27 has an end face 2 facing the passage 24.
8 and 29, if a groove 30 is provided on the inner circumferential surface of the valve sleeve 14 as shown in FIG. 5, a key groove for centering can be formed with the return passage 27. It is also possible to improve the workability of assembling the valve sleeve 14.

Furthermore, the hydraulic oil flows from the groove portion 20b to the passage 2.
4 through the return passage 27, the back pressure of the hydraulic fluid flow acting between the valve rotor 13A and the valve sleeve 14 is small compared to the conventional device (FIG. 2), and therefore, It also has the advantage of improving valve operability and sealing performance.

As described above, according to the present invention, the return passage for the hydraulic oil extending in the axial direction from a predetermined groove portion of the valve rotor is provided so as to open at the end face of the valve rotor or the valve sleeve. without the need for mechanical cutting,
It can be integrally formed by forging, precision casting, sintered alloy, etc., and has the effect of significantly improving productivity.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional example. FIG. 2 is a longitudinal sectional view of another conventional example, and FIG. 3 is a structural explanatory diagram showing a cross-sectional state from the axial direction. FIG. 4 is a longitudinal cross-sectional view of one embodiment of the present invention, and FIG. 5 is a structural explanatory view showing the cross-section from the axial direction. 11... Stub shaft, 12... Worm shaft, 13, 13A... Valve rotor, 14...
... Valve sleeve, 16 ... Rotating sliding surface, 19
a, 19b...Land part, 20a, 20b...Groove part, 21a, 21b...Port part, 22...
...Pump port, 25...Tank port, 27...
...Return passage, 28, 29...end surface.

Claims (1)

[Scope of utility model registration request] In a rotary valve that is equipped with a valve sleeve and a valve rotor that are arranged concentrically, and that selectively supplies and discharges hydraulic oil by relative rotation between the two based on input, the rotating sliding surface of the valve sleeve and the valve rotor is the rotation axis. While forming a conical surface centered on the center, the land portion of the valve sleeve and valve rotor,
A rotary rotary device characterized in that a groove portion or a port portion is formed substantially parallel to an axis, and a return passage for hydraulic oil extending in the axial direction from a predetermined groove portion is provided so as to open at an end face of a valve rotor or a valve sleeve. valve.