JPS5884204A - Flap type servo valve device - Google Patents

Abstract

PURPOSE:To prevent generation of a throttling sound by forming an outflow nozzle slantingly in the direction of a small gap in a throttle passage between a side wall and a valve seat. CONSTITUTION:As for the size of gaps between a side wall 26a of a main valve member 20 and a valve seat 34 whieh is in a slanting condition to said wall 26a, an exterio gap delta2 is bigger than an interior gap delta1. Accordingly, pressurized fluid from an outflow nozzle 31 opening in the side wall 26a flows out at high speed into a valve chamber 26 of low pressure through a throttle passage 50 between the valve seat 34 of a flap valve 38 and the side wall 26a with special tendency to flow toward the exterior part with a big gap. However, since the outflow nozzle 31 is formed slanting in the direction of a small gap, that is, relative to the side wall 26a by an angle, outflow to the exterior is difficult and the same to the interior is easy. As a result, pressurized fluid from the outflow nozzle 31 flows out spreading about evenly on the whole periphery of the valve seat 34. Thus, not only cavitation but also generation of throttling sound are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flapper type servo valve device used, for example, in a power steering device.

In a flapper-type servo valve device that is generally used in power steering devices, etc., seven flapper valves are rotatably housed in a valve body that forms an outflow nozzle, and the relative rotation between the valve body and the flapper valve allows the valve to be installed in the flapper valve. The valve seat opens and closes the outflow nozzle to generate the required pressure in the power cylinder.

In this type of 7-lap type servo valve device, Fig. 1 (
As shown in the figure, the flap valve 2 is at the maximum angle θ within the valve body 1.
The end face of the valve seat 3 is inclined so that when rotated, the end face of the valve seat 3 is exposed to the side wall 5 of the valve body 1 which opens the outflow nozzle 4, thereby closing the outflow nozzle 4. Therefore, in the angular range from the neutral position of the flapper valve 2 to just before the valve seat 3 contacts the side wall 5, the gap between the valve seat 3 and the side wall 5 is the inner gap δl, as shown in FIG. 1(B). The relationship is such that the outer gap δ2 is always larger than the above, and the pressure fluid flowing out from the outflow nozzle 4 is biased towards the outer part where the gap is larger, and cavitation is more likely to occur in this part, producing a squeezing sound (shooing sound). do.

The present invention has been made in order to eliminate such conventional problems, and the present invention prevents cavitation by dispersing the pressure fluid from the nozzle over the circumference regardless of the size of the gap in the throttle passage. ＜＜shi, hence the aperture sound (
The purpose of this is to prevent the occurrence of a hissing sound.

An example in which the present invention is applied to a servo valve device of a power steering device will be described below with reference to the drawings.

FIG. 2 shows a power steering device, in which a power cylinder 11 fitted with a piston 10 is provided on one side, and a flapper-type servo valve device 12 for controlling the pressure fluid supplied to the power cylinder 11 is housed on the other side. Valve housing 1
3 is provided. A rack 14 is carved on a part of the circumference of the piston 10, and the rack 14 meshes with a sector gear 16 of a cross shaft 15 connected to a steering wheel via a link mechanism. A screw shaft 18 is screwed onto the piston 10 via a ball 17.
A main valve member 20 (see FIGS. 3 and 4) having a sleeve valve member 19 fitted into the valve housing 13 is integrally formed at one end of the main valve member 8 .

A valve chamber having side walls facing each other is formed in the main valve member 2o in the axial direction, and the two valve chambers are connected to the two valves by a sealing separation member 23 fitted and fixed to the central portion of the main valve member 20 in the axial direction. It is sealed and separated into chambers 25 and 26. One valve seat 2
As shown in FIG. 3, a pair of distributing nozzles 2? , 28 are opened to face each other, and this valve chamber 25
is in communication with the supply port 29.

In addition, a pair of outflow nozzles 31 and 32 are opened opposite each other in both side walls 26a of the other valve chamber 26, as shown in FIG. 4, and this valve chamber 26 is communicated with the discharge port 35.

One of the valve chambers 25 accommodates a first seven-lap valve 37 with circular valve seats 33 attached on both sides for controlling the opening and closing of the distribution nozzle 27.28, and the other valve chamber 26 accommodates the outflow nozzle. 31.32 A second 7 flapper valve 38 with circular valve seats 34 attached on both sides for controlling opening and closing is housed, and these flapper valves 37.3811 are connected to the first 7 flapper valve to obtain an appropriate steering reaction force when steering. The rotation radius of the second flapper valve 38 is configured to be larger than the rotation radius of the second flapper valve 37.

The first and second seven-turn valves 37 and 38 are integrally formed with a steering shaft 39 rotatably supported by a bearing member, and the steering shaft 39 is rotatably supported by a bearing member.
9 is connected to the steering handle via a circuit joint and a handle shaft. A torsion bar 40 is inserted through the centers of the screw shaft 18, the first and second flapper valves 37, 38, and the steering shaft 39.
Both ends of the screw shaft 18 and the steering shaft 39 are connected to the screw shaft 18 and the steering shaft 39, respectively.

Said distribution nozzle 27.28 and outflow nozzle 31.32
One of the distribution nozzles 27 and one of the outflow nozzles 31 are communicated with an annular groove 43 formed in the sleeve valve member 19 via communication passages 41 and 42, and the annular groove 43 communicates with the passage 4.
4 to the left chamber 11a of the power cylinder 11, and the other distribution nozzle 28 and the other outlet nozzle 32 communicate with each other by a communication passage 45, 46, and the screw shaft 18
The power cylinder 11 is connected to the power cylinder 11 through a passage 47 bored at one end.
The right ventricle 11b of the right ventricle 11b.

In the seven-lap type servo valve device having the above configuration, the gap between the side wall 26a of the main valve member 20 and the valve seat 34 is such that the outer gap δ2 is larger than the inner gap δ1, as shown in FIG. , the pressure fluid tends to flow out toward the larger outer portion of this gap. Therefore, the essential part of the present invention is that the outflow nozzles 31 and 32 are formed to be inclined at an angle α in the direction of the smaller gap, that is, with respect to the side wall 26a, so that the pressure fluid is distributed over the entire circumference of the valve seat 34. The reason is that they were made to leak out.

Since the flapper type servo valve device of the present invention is configured as described above, when the steering handle is in the neutral state,
As shown in FIGS. 3 and 4, the first and second seven-way valves 37, 38 are held in neutral positions within the valve chamber 25, 26, so that the supply port 29 supplies the first valve chamber 25. The pressure fluid is publicly distributed to the distribution nozzles 27 and 28, and this distributed flow is discharged from the outlet 35 through the valve chamber 26 from the outflow nozzles 31 and 32, so that the left and right chambers 11a of the power cylinder 11 , the pressure fluid in Ilb does not increase in pressure and the steering wheels remain neutral.

However, when the steering handle is completely rotated, for example to the left, the first and second flapper valves 37,38 close one distribution nozzle 28 and the outflow nozzle 31 and open the other distribution nozzle 27 and outflow nozzle 32. As a result, the pressure fluid supplied to the valve chamber 25 is distributed only to the distribution nozzle 27 and sent under pressure to the outflow nozzle 31, but since the amount of outflow from this outflow nozzle 31 is restricted, the pressure increases, and this pressure increase The pressure fluid is introduced into the cylinder left chamber 11a and the piston 10 is pushed rightward, and the fluid in the cylinder right chamber 11b is discharged through the outflow nozzle 32.

At this time, the pressure fluid whose outflow from the outflow nozzles 31, 32 is restricted passes through the throttle passage 50 between the valve seat 34 of the second seven-way valve 38 and the side wall 26a to the low-pressure valve chamber z6.
It flows inwards at high speed, and tends to flow particularly towards the outer parts where there are large gaps. However, in the present invention, as described above, the outflow nozzles 31 and 32 are formed to be inclined in the direction in which the gap becomes smaller. Outflow nozzle 31.
The pressure fluid from the valve seat 32 is distributed almost uniformly over the entire circumference of the valve seat 34 and flows out, thereby preventing unevenness of the pressure fluid due to the size of the gap and the occurrence of cavitation and squeezing noise (shooing sound) caused by this. .

As described above, the 7-lap type servo valve device of the present invention has a configuration in which the outflow nozzle is formed to be inclined toward the direction where the gap of the throttle passage formed between the side wall and the valve seat is small.
The pressure fluid can be distributed almost uniformly over the entire circumference of the valve seat and flowed out. 1. It has the advantage of being able to prevent the generation of throttling noise (swooshing sound).

[Brief explanation of drawings]

Figures 1(A) and 1(B) are cross-sectional views of main parts showing changes in the throttle passage in a conventional 7-lap type servo valve device;
The figure is a longitudinal cross-sectional view of a power steering device incorporating a seven-turn type servo valve device showing an embodiment of the present invention, and FIG.
-II, I! FIG. 4 is a sectional view taken along the line IV-W in FIG. 2, and FIG. ...Main valve member, 26a...Side wall, 31.32.
... Outflow nozzle, 34@... Valve seat, 5o... Throttle passage. Patent applicant Toyota Machinery Co., Ltd. (A) Figure (B) Figure 3 Figure 4 Figure 1 F. 5 (Capital) (A) (B)

Claims (1)

[Claims] (1) A main valve member having a side wall opening an outflow nozzle for pressurized fluid, and a flapper valve having a valve seat for opening and closing the outflow nozzle, wherein relative rotation of the main valve member and the flapper valve causes the side wall and the In a servo valve device that controls the pressure of pressurized fluid supplied to a device to be put to sleep by changing the gap in a throttle passage between valve seats that are inclined with respect to a side wall, the outflow nozzle is connected to the gap in the throttle passage. A flapper type servo valve device characterized by being formed to be inclined in a small direction.