JPH0216937Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a power steering device equipped with a rotary type control valve.

<Prior Art> In general, in a power steering device equipped with a rotary type control valve consisting of a sleeve valve member and a rotor valve member that fit together so as to be able to rotate relative to each other, a port groove to be formed on the outer periphery of the rotor valve member is hobbed. If done through machining, machining efficiency can be improved and it is extremely effective for mass production.

On the other hand, since the machining of the port groove to be formed on the inner circumference of the sleeve valve member is controlled, it is generally done by broaching. A sealing ring is fitted to close the port grooves, and these sealing rings hermetically separate the plurality of port grooves in the circumferential direction.

However, in such a configuration,
It is difficult to tightly fit the sealing ring to the end face of the port groove, and in some cases there is a problem in that pressure oil leaks from both ends of the port groove.

Moreover, as mentioned above, when the port grooves of the rotor valve member are hobbed, the port grooves are barrel-shaped, whereas the port grooves of the sleeve valve member are straight due to broaching. There is a problem in that the passage area between both port grooves does not change proportionally to the relative rotation angle of the valve member, and as a result, it is impossible to provide linearity to the pressure characteristics with respect to the valve rotation angle.

<Purpose of the invention> The purpose of the invention is to eliminate the cause of oil leakage by eliminating the sealing ring, and also to provide linearity to the pressure characteristics with respect to the valve rotation angle even if the port groove of the rotor valve member is barrel-shaped. The goal is to be able to do so.

<Structure of the invention> In order to achieve the above-mentioned object, the present invention includes a sleeve valve member consisting of a sleeve body having a supply groove and a pair of distribution grooves, and a thin-walled cylindrical body fitted into the sleeve body. This cylindrical body is made up of two members, and a chain-shaped port groove is formed in this cylindrical body to complement a barrel-shaped port groove formed on the outer periphery of the rotor valve member.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. In FIG. 1, reference numeral 10 denotes a gear housing forming the main body of the power steering device, and a pinion shaft 11 is rotatably supported at both ends by bearings 12 and 13, respectively, and intersects with the gear housing 10. It meshes with the rack teeth 15 of the rack shaft 14 which is slidable in the direction. Both ends of the rack shaft 14 are connected to steering wheels via a required steering linkage, and a power cylinder 16 is connected to the rack shaft 14.
A piston 17 (see FIG. 2) is operatively connected thereto.

The gear housing 10 includes a valve housing 18.
is fixed, and a rotary type control valve 20 is housed in the valve hole 19 of the valve housing 18. This rotary type control valve 20 includes a sleeve valve member 21 that is relatively rotatable about the axis of the pinion shaft 11.
and a rotor valve member 22, this sleeve valve member 21 is connected to the pinion shaft 11 by a connecting pin 23, and the rotor valve member 22
is integrally formed with a steering shaft 24 connected to the steering handle, and this steering shaft 24 is connected to the pinion shaft 1.
1 via a torsion bar 25.

A plurality of port grooves 27 are formed on the outer periphery of the rotor valve member 22 at equal angular intervals on the circumference. These port grooves 27 are formed by hobbing,
As a result, the port has a barrel shape with a wider center portion, as shown in FIG. As shown in FIG. 4, first and second pressure control surfaces 29 and 30, which are inclined at different angles, are formed on both edges of the land portion 28 located between the port grooves 27, respectively.

The sleeve valve member 21 also includes a sleeve body 31 that rotatably fits into the valve housing 18;
A thin cylindrical body 3 that is fitted into the sleeve main body 31 and relatively rotatably fitted to the rotor valve member 22
It is composed of two members: 2 and 2. A supply groove 33 and a pair of distribution grooves 35 and 36 are formed on both sides of the supply groove 33 on the outer periphery of the sleeve body 31.
5 and 36 are connected to the left and right chambers of the power cylinder 16 through supply and discharge ports 37 and 38, respectively. The thin-walled cylindrical body 32 has a port groove having both edges shaped to complement both edges of the barrel-shaped port groove 27 described above, that is, a continuous port groove with a narrow center portion as shown in FIG. A plurality of port grooves 4 each having a circular shape.
0 are formed at equal angular intervals on the circumference, a supply hole 41 communicating with the supply groove 33 is opened in this port groove 40, and distribution holes 43 communicating with a pair of distribution grooves 35 and 36 are opened on both sides of this supply hole 41. , 44 are opened at the inner periphery of the thin cylindrical body 32. The port groove 40 is formed by punching with a press or the like,
After this port groove 40 is formed, the thin cylindrical body 32
is driven into the sleeve body 31 and integrated.

Both the port grooves 27 and 40 described above are arranged in such a manner that the port groove 40 straddles the two port grooves 27 when the sleeve valve member 21 and the rotor valve member 22 are in a neutral state. However, both port grooves 27, 4
0 has a shape in which both edges complement each other, so the communication gap between the port grooves 27 and 40 is almost constant at any position in the axial direction, and therefore the communication gap between the port grooves 27 and 40 is approximately constant at any position in the axial direction. The communication area changes proportionally to the valve rotation angle.

That is, the communication area between the port grooves 27 and 40 rapidly decreases in the overlap section where the rotor valve member 22 rotates with respect to the sleeve valve member 21 from X0 to X1, but since it does not yet function as a throttle, the pressure changes. In the section from X1 to X2, the communication area gradually decreases due to the action of the first pressure control surface 29, resulting in a smooth pressure rise, and in the section from X2 to X3, the communication area gradually decreases due to the action of the first pressure control surface 3.
Due to the effect of zero, the rate of decrease in the communication area increases and the pressure rapidly increases. As a result, the pressure characteristic with respect to the valve rotation angle becomes a linear two-stage characteristic as shown in FIG.

In the above configuration, when the rotor valve member 22 is rotated in the direction of the arrow in FIG. 40
The water is distributed to one of the pair of distribution grooves 35 and 36 through the drain hole 45, and the other is communicated to the tank side through the discharge hole 45. As a result, the piston 17 of the power cylinder 16 is moved to the right, and the manual steering torque is assisted.

In this case, since both the port grooves 27 and 35 of the sleeve valve member 21 and the rotor valve member 22 have a cone shape and a barrel shape with their respective edges complementary to each other, both the port grooves 27 and 35 of the sleeve valve member 21 and the rotor valve member 22 have The communication area between the valves 25 and 25 is increased in proportion to the valve rotation angle, and linearity is brought about in the pressure characteristics with respect to the valve rotation angle.

<Effects of the invention> As described above, in the present invention, the sleeve valve member is composed of two members: a sleeve body and a thin-walled cylindrical body fitted into this sleeve body, and the rotor valve member is attached to this cylindrical body. Since the configuration has a cone-shaped port groove that complements the barrel-shaped port groove formed on the outer periphery, even if the port groove of the rotor valve member becomes barrel-shaped by hobbing, the valve rotation angle will not change. Furthermore, by forming the port groove on the sleeve valve member side into a thin cylindrical body that is fitted into the sleeve body, it is possible to easily process the port groove, and it is possible to easily process the port groove compared to conventional It also has the effect of preventing oil leakage from the end face of the port groove, which is seen in those using sealing rings.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of the power steering device, and FIG. 2 is a cross-sectional view of the power steering device.
Fig. 3 is an enlarged cross-sectional view as viewed from the line arrow, Fig. 3 is an expanded view of the port groove, Fig. 4 is a detailed sectional view of the part shown in Fig. 3, and Fig. 5 is a diagram showing pressure characteristics with respect to valve rotation angle. . DESCRIPTION OF SYMBOLS 11... Pinion shaft (output shaft), 16... Power cylinder, 18... Valve housing, 20... Rotor type control valve, 21... Sleeve valve member, 22...
...Rotor valve member, 24...Steering shaft, (input shaft), 2
7...Port groove, 31...Sleeve body, 32...
...Thin cylindrical body, 33... Supply groove, 35, 36...
Distribution groove, 40...port groove.

Claims (1)

[Scope of utility model registration request] A sleeve valve member rotatably fitted to the valve housing is coupled to an output shaft, a rotor valve member rotatably fitted to the sleeve valve member is coupled to an input shaft, and a manual input shaft is applied to the input shaft. In a power steering device that controls the supply and discharge of pressure oil to a power cylinder by relative rotation between a rotor valve member and a sleeve valve member based on steering torque, the sleeve valve member is configured to be supplied with pressure oil. It is composed of two members: a sleeve body having a supply groove and a pair of distribution grooves communicating with both chambers of the power cylinder, and a thin cylindrical body fitted into the sleeve body,
Barrel-shaped port grooves are formed on the outer periphery of the rotor valve member at equiangular positions on the circumference, and barrel-shaped port grooves are formed in the thin cylindrical body of the sleeve valve member between each of the barrel-shaped port grooves. A power steering device in which claw-shaped port grooves having both edges shaped to complement the edges are formed at equiangular positions on the circumference.