JPS58224862A - Rotary valve - Google Patents

Abstract

PURPOSE:To prevent a pressure fluid from leaking at a space between concave grooves that abut each other in an accurate manner, by sealing one side end face with a projection adhering to the other side end face so tightly. CONSTITUTION:Each fitting hole 29 whose diameter is larger than that of a cylindrical hole 25 is made up at both ends of a sleeve valve member 24. At the end face of the fitting hole 29, projections 31 are made up over the whole circumference along an inner form of the sleeve valve member 24. A sealing ring 30 sealing the end part of each of concave grooves 27 is pressed in the fitting hole 29 to the exent of a specified position with the specified press fit allowance. Each of these projections 31 is crushed by the press fit of this sealing ring 30 and likewise the end face of the sealing ring 30 bites into each projection 31 whereby the sealing ring 30 and these projections 31 are united together over the whole circumference without any clearance left behind. With this method, a space between individual end parts of plural concave grooves 27 is accurately sealed up, so that a pressure fluid leakage can be well prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary valve used in a power steering device.

Conventionally, this type of rotary valve, particularly its sleeve valve member, is formed by forming a concave groove in the axial direction on the inner peripheral surface of the cylindrical hole of the sleeve valve member by passing a broach tool or a similar cutting tool therethrough. The end of the groove is closed by placing a sealing ring at the end of the groove.

The above-mentioned conventional rotary valve has the advantage that the concave groove can be easily and precisely machined by broaching, but on the other hand, the end face accuracy of the sealing ring, that is, the perpendicularity of the end face to the axis of the sealing ring, is not achieved, or the sleeve valve If foreign matter enters between the end faces of the member and the sealing ring, a gap will be created between both end faces, and this gap will cause leaks between the adjacent concave grooves, making it impossible to obtain the required control characteristics of the valve. was there.

This can be countered by precisely machining the sleeve valve member and each end face of the sealing ring, or by providing a device to prevent foreign matter from entering, but all of these methods increase processing costs. There were drawbacks.

The present invention has been made in order to solve such problems in the prior art, and its purpose is to provide a loaf valve in which the sleep valve member and the end face of the sealing ring can be reliably brought into close contact with each other, thereby preventing leakage of pressure fluid. The purpose is to provide a 1J valve.

Yet another object of the present invention is to provide an fZ rotary valve whose sleeve valve member and sealing ring are easy to manufacture.

Embodiments of the present invention will be described below based on the drawings.

What is shown in FIGS. 1 and 2 is an example in which the present invention is applied as a control valve of a power steering device, and 1° is a housing main body forming the main body of this power steering device. A binion shaft 13 is rotatably supported in the housing body 10 via a pair of bearings 11 and 12, and a rack shaft 14 is mounted on the binion shaft 13, which is slidable in a direction crossing the binion shaft 13. Rack teeth 15 are in mesh. This rack shaft 14
is the piston 1 of the power cylinder 16 as shown in FIG.
7, both ends of which are connected to the steering wheels via the required steering linkage.

On the other hand, inside the valve housing 18 fixed to the housing body 1o, there is a steering shaft 2o flexibly connected to the binion shaft 13 via a torsion bar 19, and a rotary pulp 21 whose rotation is controlled by the steering shaft 20. It is accommodated. The rotary valve 21 includes a spool valve member 22 integrally formed on the steering shaft 20 and a pinion shaft 1.
Sleeve valve material 24 connected to No. 3 via a connecting pin 23
The spool valve member 22 is fitted and supported in a cylindrical hole 25 formed in the sleeve valve member 24 so as to be relatively rotatable.

As shown in FIG. 2, a plurality of grooves 26 extending in the axial direction are formed at equal intervals in the circumferential direction on the outer peripheral surface of the spool valve member 22, and similarly, the cylindrical hole 25 of the sleeve valve member 24 also extends in the axial direction. A plurality of extending grooves 27 are formed at equal intervals in the inner circumferential direction,
Relative rotation of the spool valve member 22 and the sleeve valve member 24 opens and closes the grooves 26 and 27, thereby controlling the supply and discharge of pressurized fluid to the power cylinder 16.

Furthermore, a fitting hole 29 having a larger diameter than the cylindrical hole 25 is formed at both ends of the sleeve valve member 240, as shown in FIG. As shown in FIG. 4, a protrusion 31 is formed along the entire circumference along the inner surface shape of the sleeve valve member 24.
1, the end face of the fitting hole 29 is first machined flat, and then the outer surface of the sleeve valve member 24 and the cylindrical hole 2 are machined flat.
5. Only the inner surface is surface hardened by induction hardening, etc.
After that, the end surface of the fitting hole 29 whose surface has not been hardened is
This can be easily accomplished by plastically deforming the sleeve valve member 24 by using a mold having a shape corresponding to the inner surface shape of the sleeve valve member 24.

A sealing ring 30 for sealing the end of the groove 27 is press-fitted into the fitting hole 29 to a predetermined position with a predetermined press-fitting allowance. By press-fitting the sealing ring 30, the projection 3
1 is crushed, or the end face of the sealing ring 30 bites into the protrusion 31, so that the sealing ring 30 and the protrusion 31 are brought into close contact with each other without any gaps over the entire circumference. As a result, the plurality of grooves 27
This ensures a secure seal between each end of the valve and prevents pressure fluid from leaking.

In the above embodiment, an example was described in which the protrusion 31 is formed on the side of the valve member 24, but a protrusion of the same shape as that is formed on the side of the sealing ring 3o, and this sealing ring 30f: Fitting hole 2 of sleeve valve member 24
Even if the protrusion of the sealing ring 30 is brought into close contact with the end surface of the fitting hole by press-fitting the sealing ring 30 by 9vc, the same effect as mentioned above can be obtained.

As described above, according to the rotary valve of the present invention, a protrusion is formed on the end face of either one of the fitting hole of the sleeve valve member and the sealing ring that is press-fitted into the fitting hole, along the inner shape of the sleeve valve member. Since the protrusion is formed all around the circumference and the protrusion is tightly attached to the other end face to seal the end face, it is possible to accurately prevent leakage of pressure fluid between adjacent grooves. In addition, since the end faces of the sleeve valve member and the sealing ring do not require higher machining precision than necessary, machining is easy and machining costs can be reduced.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a longitudinal sectional view of a power steering device equipped with the rotary pulp of the present invention, and FIG.
The figures are an enlarged sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is a vertical sectional view of the sleeve valve member showing the state in which the sealing ring is fixed, and Fig. 4
The figure is a sectional view taken along the line IV-IV in FIG. 3. 22...Spool valve member, 24...Sleeve valve member, 26.27...Concave groove, 29...*Fitting hole, 30...
- Sealing ring, 31...protrusion. Patent applicant Toyota Machinery Co., Ltd.

Claims (1)

[Claims] (1) A sleeve valve member in which a plurality of grooves extending in the axial direction are formed in the inner hole, and a spool valve member that fits into the inner hole of the sleeve valve member so as to be able to rotate relative to each other. In a rotary valve for controlling the supply and discharge of pressurized fluid, a fitting hole having a diameter larger than that of the inner hole is formed at an end of the sleeve valve member, and a sealing ring press-fitted into the fitting hole is provided, A rotary valve in which a protrusion is formed around the entire circumference of one end face of the sealing ring and the fitting hole along the inner surface shape of the sleeve valve member, and the protrusion is brought into close contact with the other end face.