JPS59230864A - Rotary valve for power steering gear - Google Patents

Abstract

PURPOSE:To prevent a squeezing sound due to cavitation from occurring, by arranging a control orifice to be formed by a spool valve component and a plurality of land parts on an inner circumferential surface of a sleeve valve component either between a supply hole and a distribution hole or between the distribution hole and a discharge hole in two steps. CONSTITUTION:Two step orifices Sr11, Sr12 or Sl11, Sl12 to be formed by relative movement of a sleeve valve component 21 and a spool valve component are formed between a supply hole 31 and distribution holes 33, 34 of a valve. Two step orifices Sl13, Sl14 or Sr13, Sr14 are formed similary between the distribution holes 33, 34 and a discharge hole 44. Lowering of pressure at the time of outflow of a high pressure fluid to a low pressure side is carried out extending over two steps through these two step orifices. As the lowering of pressure, therefore, at the individual orifice is reduced by half, cavitation becomes difficult to occur and a squeezing sound does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rotary valve used in a power steering device that operates a valve member based on a manually operated torque and controls supply and discharge of pressure fluid to a power cylinder. It is something.

<Prior art> In general, in the control A11 valve of a power steering device, a throttle is provided on the discharge side of the control valve to control the passage area to increase the back pressure on the discharge side, thereby causing high-pressure fluid to flow out at high speed to the low-pressure side. Aperture noise due to cavitation that occurs when
This is to prevent the hissing sound.

In order to provide such back pressure, a special valve device (=j
In addition to the added pressure, back pressure acts on the tank side boat,
There was a problem that reduced the sealing function and caused oil leakage.

Applying further back pressure will involve power loss,
This was disadvantageous from an energy saving perspective.

<Objective of the Invention> An object of the present invention is to prevent the generation of squeezing noise due to friction caused by applying such back pressure.

<Configuration of the Invention> The characteristic configuration of the present invention is that a plurality of runs 1 are formed on the inner circumferential surfaces of the spool valve part l and the sleeve valve part H, which are relatively rotatable.
A control orifice formed by a portion is arranged between the supply hole and the distribution hole or between the distribution hole and the discharge hole so as to have a throttling effect in at least two stages.

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

Figure 1 shows a rack and pinion type power steering device, with 10
is a housing main body forming the main body of the power steering device. In this housing body 10, a pinion shaft 11 is rotatably supported at both ends by bearings 12 and 13, and rack teeth 1 of a rack shaft 14 are slidable in a direction crossing the pinion shaft 11.
It meshes with 5.

Both ends of the rank shaft 14 are connected to steering wheels via a required steering linkage, and a piston 17 (see FIG. 2) of a power cylinder 16 is operatively connected to the rank shaft 14.

A valve housing 18 is fixed to the housing body 10, and a control valve 20 is housed in a valve hole 19 of the valve housing 18. This control valve 20 is composed of a sleeve valve member 21 and a spool valve member 22 that fit into each other so as to be able to rotate relative to each other about the axis of the pinion shaft 11, and this sleeve valve FfE21 is connected to the pinion shaft 11 by a connecting pin 23. and also spool valve 9B+4
22, and a steering shaft 24 connected to the 1 side steering wheel is integrally formed, and this 1,000 steering shaft 24 is connected to the pinion shaft 1.
It is flexibly connected via a 1-version bar 25 connected to 1 by a pinion 51.

As shown in FIG. 2, grooves 30 extending in the axial direction are provided on the inner periphery of the sleeve valve portion +A21 at appropriate intervals in the circumferential direction.
A plurality of grooves are carved, and a run +: ri+ 3 is carved between each groove.
6 is formed.

A supply hole 31 through which pressure fluid is supplied from the pump is opened 1-1 in a pair of lands 36 facing each other along the diameter line J2, and a concave groove 30 forming an angular phase of approximately 45 degrees with the supply hole 31, that is, 1-1.
Distribution ports 33 and 34 that communicate with the left and right chambers 16a and 16b of the power cylinder 16 are opened in the groove 30 provided between the two land portions 36.

On the other hand, a groove 35 is formed on the outer periphery of the spool valve part 22 so as to face the groove 30 of the sleeve valve member 21, and a land part 37 is formed between the grooves 35. A recess a35 having an angular phase of 90 degrees with the supply hole 31 (one land portion 37 from the runt portion facing the distribution port 33, 34)
A discharge hole 44 that communicates with the tank side is opened in the drain hole 44 that communicates with the tank side.

In this way, merifices formed at the edges of each land are arranged in series in two stages not only between the supply hole 3I and the distribution holes 33, 34, but also between the distribution holes 33, 34 and the discharge hole 44. , each orifice gap is equal. As a result, as shown in the schematic developed view of the orifice section shown in FIG. 3, the supply hole 31 and the pair of distribution holes 33
．． A spool valve member 2 is provided on one side of each communication path between the spool valve member 34 and the spool valve member 2.
Two-stage orifice 5Ill I+ 37! that is operated to be closed by relative rotation in the left direction of 2! + 2 is formed and the other is opened with a two-stage orifice S rI I
+5r12 is formed.

Furthermore, a two-stage orifice 5II3°S 7!1 that is operated to be closed by relative rotation is configured in one of the communication passages between the pair of distribution holes 33, 34 and the discharge hole 44, and the other is the opened two-stage orifice Sr+3. Sr+
4 is composed.

Two-stage orifice 3zll, 5x12 and Sr1'3 on the side to be closed. S4+4 performs a pressure control function by restricting the fluid flowing out from the high pressure side to the low pressure side, and since each of the two stage orifices is arranged in series, the pressure drop down to the orifice of each stage is on the high pressure side. This means that the pressure difference on the low pressure side is halved to approximately one-half. Along with this, cavitation also becomes less likely to occur.

Since the rotary valve of the present invention is constructed as described above, when the handle is in the neutral state, each control orifice sz, l, . . . 5114, as shown in FIG.
Sr1. . . 5rI4 gaps are maintained equally, so that the pressure fluid supplied from the supply hole 31 to the groove 35 is discharged from each orifice and from the discharge port 44. Therefore, the fluid pressure in the left and right chambers of the power cylinder 16 does not increase, and the steering wheels maintain a neutral state.

Now, when the handle is rotated, for example, counterclockwise, the torsion bar 25 is twisted, and the spool valve part +A22 is rotated in the direction of the arrow in FIG. 2 relative to the sleeve valve part +A21. This opens the control orifice 5r11+5r12 provided between the supply hole 31 and the distribution hole 33.34,
Control orifice 5ffl,.

si+2 is narrowed and acts to distribute the supply fluid to the distribution hole 33 side. Along with this, the distribution holes 33, 34 and the discharge hole 4
Control orifice Sr provided between 4 1.3. Sr.
14 is opened and the control orifice SP+3, 5614 is narrowed to direct the discharge fluid from the distribution hole 34 to the tank side.

As a result, the fluid pressure on the supply hole 31 side increases, and the distribution hole 3
3 to the right chamber 16b of the power cylinder 16 to push the piston 17 to the left, while fluid in the left chamber is discharged from the distribution hole 34 to the discharge hole 44.

Here, the control orifice Sjl! ++, 5412
and S''+313ff14 have a pressure drop in two stages that act to suppress the outflow of high-pressure fluid to the low-pressure side, so the pressure drop at each orifice is halved, making cavitation less likely to occur, and the associated There is an advantage that no squeezing sound (hissing sound) is generated, and there is no pressure loss or power loss because no back pressure is applied.

<Other Embodiments> In the second embodiment, the supply hole 31 and the force distribution hole 33.3
Control orifices for controlling pressure are provided in two stages not only in the communication path between the distribution holes 33 and 34 and the discharge hole 44, but also in the communication path between the distribution holes 33 and 34 and the discharge hole 44. Although the leakage is kept equal, the supply hole 3 is not limited to this, as shown in the developed schematic diagram in FIG.
A control orifice that performs pressure control is provided only in the communication path between the distribution hole 33, 34 and the distribution hole 33, 34, or, as shown in the developed schematic diagram in FIG. &J is also effective. In this case, the orifices other than the orifice that performs the pressure control function are constructed so that their orifice gaps are made small and are closed before the pressure control orifice is closed to perform the direction control function. In order to make this configuration easier to understand, the orifice for pressure control is shown with a chamfered portion C, and the orifice for direction control is shown without a chamfered portion.

<Effects of the Invention> As described above, the present invention forms an orifice for pressure control in two stages in the communication path between the supply hole and the distribution hole or in the communication path between the distribution hole and the discharge hole. As a result, the pressure drop at each orifice is halved, which has the effect of eliminating the squeezing noise caused by cavitation.

Along with this, there is no need to apply back pressure as in the conventional case, so there is an advantage that pressure loss and power loss can be significantly reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional view of a power steering control valve, and FIG. 2 is an enlarged cross-sectional view taken along the line n--n in FIG. 3 is a schematic diagram of the control orifice section in FIG. 2, FIG. 4 is a schematic diagram of the second embodiment, and FIG. 5 is a schematic diagram of the third embodiment. 16...Power cylinder, 18...valve housing,
20... Control valve, 21... Sleeve valve part shrine, 22...
... Spool valve member, 30 ... Concave groove, 31 ... Supply hole, 33. 34 ... Distribution hole, 44 ... Discharge hole, 30
．． 35...concave groove, 36.37...part of run 1, 5N
II~s7! , 4+5rll to 5r14... Orifice for pressure control, C... Chamfered portion. Patent applicant Toyota] Nikki Co., Ltd.

Claims (2)

[Claims] (1) A spool valve member and a spool valve member that are rotatable relative to each other are housed in the valve housing, and pressure fluid is supplied to the inner circumferential surface of the sleeve valve 4A at a circumferentially curved distance. Open the hole and distribution hole and wipe. - A pressure fluid discharge hole is opened on the outer circumferential surface of the spool valve part, spaced apart in the circumferential direction from the supply hole and the distribution hole, and further on the fitting surface of both the sleeve valve member and the spool valve member. teeth,
A plurality of run portions are formed at intervals of 11% in the circumferential direction, at least two land portions are formed between the supply hole and the distribution hole, and an orifice is formed between each runt portion. A rotary valve for a power steering device, comprising a two or more stage throttle between the supply hole and the distribution port with equal gaps. (2) A sleeve valve member and a spool valve member that are rotatable relative to each other are housed in the valve housing, and the inner peripheral surface of the sleeve valve member has pressure fluid supply holes spaced apart in the circumferential direction. 53 is opened, and a pressurized fluid discharge hole is opened on the outer circumferential surface of the spool valve member at a distance in the circumferential direction from the supply hole and the distribution hole, and both sub-rib valves 91 (
44 and the fitting surface of the spool valve member, a plurality of land portions are formed spaced apart in the circumferential direction, and at least two land portions are formed between the distribution hole and the discharge hole, and each A rotary valve for a power steering device, wherein the orifice gaps formed between the land portions are made equal to each other, and the distribution hole is configured to have two or more stages of restriction between the JJI outlet holes.