JPS63297170A - Fluid squeezing device - Google Patents

Abstract

PURPOSE:To recover the pressure of a fluid on a collision face and prevent the occurrence of cavitation by forming the collision face against which the fluid from an orifice collides at a right angle on part of the minimum-diameter section side of a sheet union. CONSTITUTION:When a handle is operated and the pressure of a fluid in a servo valve side passage 12 becomes higher than that in a reaction mechanism side passage 13, part of the fluid in the servo valve side passage 12 flows to the reaction mechanism side passage 13 via a communicating passage 17. At this time, the fluid passes the first passage 34, the minimum-diameter hole 31, an orifice 40b, a space 40d, a circular gap 50, a communicating passage 51, and a cylindrical inner space 44 and expanded in this route, and the pressure of the fluid is decreased in stages. The fluid with its flow speed increased and pressure decreased by the orifice 40b recovers its pressure by colliding against a collision face 52, thus the occurrence of cavitation due to the decreased pressure can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fluid restricting device that reduces the pressure of fluid in stages to suppress the occurrence of cavitation.

<Prior Art> As such a fluid restriction device, a plurality of restriction members each having a cup shape and an orifice formed at the bottom are fitted in series into a hole in a housing, and an internal space for expanding fluid is formed between the restriction members. be.

<Problems to be solved by the invention> In the above-mentioned problem, cavitation is likely to occur at the final stage orifice where the back pressure is lowest, and the wetted area of the fluid at the final stage orifice is small, so the noise due to cavitation is There was a big problem.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned problems, and includes fitting a cup-shaped aperture member and a seat union into the small-diameter hole and the large-diameter hole formed in the housing, respectively. The seat union has a minimum diameter part that forms an annular gap with the cylindrical part of the throttle member, a small diameter part that forms a cylindrical internal space with the large diameter hole, and a small diameter part that is fitted into the large diameter hole. A collision surface is formed at one end of the sheet union on the side of the smallest diameter hole at a position away from the bottom of the orifice, with which the fluid from the orifice collides at right angles. A communication path is formed in the union in the radial direction to communicate the annular gap and the cylindrical internal space.

The fluid discharged from the pump and flowing into the minimum diameter hole of the housing passes through the orifice and the space inside the cup-shaped throttle member, collides with the collision surface, and then passes through the annular gap.

It flows into the cylindrical internal space through the communication path. At this time, the pressure drops at the orifice, recovers at the collision surface, and further drops at the annular gap.

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

In FIG. 4, 10 is a pump that discharges fluid; 10a;
11 is a flow control valve that controls the discharge flow rate from the pump to a constant flow rate; 11 is a flow divider that divides the fluid from the flow rate control valve 10a into the servo valve side passage 12 and the reaction force mechanism side passage 13 at a constant flow rate; 14; 14a is a power cylinder that generates a force to steer the tires of the circuit; 14a is a servo valve that distributes fluid between the left and right chambers of the power cylinder 14 in accordance with the steering of the circuit handle; 15 is the pressure of the fluid in the reaction force mechanism side passage 13; 16 is a reaction force mechanism that regulates the relative rotation between the input shaft 16a on the handle side and the output shaft 16b on the tire side, and 17 is a connection that connects the servo valve side passage 12 and the reaction force mechanism side passage 13. The passage, 18, is a fluid restriction device installed in the communication passage 17. When the handle is operated and the pressure of the fluid in the servo valve side passage 12 becomes higher than the reaction force mechanism side passage 13, a part of the fluid in the servo valve side passage 12 flows to the reaction mechanism side passage 13 via the communication passage 17. It looks like this.

As a result, the pressure of the fluid in the reaction mechanism side passage 13 increases, making the handle heavier. The pressure of the fluid flowing through the communication passage 17 is reduced by the fluid restricting device 18, which has the role of restricting the flow rate of the fluid flowing from the servo valve side passage 12 to the reaction force mechanism side passage 13.

In FIG. 1, 30 is a housing of the fluid restricting device 18, and the housing 30 is formed with a minimum diameter hole 31, a small diameter hole 32, and a large diameter hole 33 in series. Further, the housing 30 is formed with a first passage 34 that communicates at right angles with the minimum diameter hole 31 and a second passage 35 that communicates at right angles with the large diameter hole 33, and the first passage 34 communicates with the servo valve side passage 12. , the second passage 35 communicates with the reaction force mechanism side passage 13.

The small diameter hole 32 has a cup-shaped orifice 40 at the bottom 40a.
The aperture member 40 having the shape b is fitted with the bottom portion 40a facing the minimum diameter hole 31 side. The aperture member 40 has a space 40 which is continuous with the bottom part 40a at right angles and has one end open inside.
A cylindrical portion 40C having a shape d is formed. Large diameter hole 3
A seat union 43 is screwed and fixed to 3, and this seat union 43 has a minimum diameter part 43a that is slightly smaller in diameter than the inner circumference of the cylindrical part 40c of the aperture member 40, and a minimum diameter part 43a that has the same diameter as the aperture member 40 and has one end attached to the aperture member 40. A small-diameter portion 43b and a large-diameter portion 43c having the same diameter as the large-diameter hole 33 are continuously formed in contact with each other, and a second
As shown in the figure, an annular gap 50 is formed, and the large diameter hole 33
A cylindrical internal space 44 is formed between the small diameter portion 43b and the small diameter portion 43b. As shown in FIG. 3, a communication path (slit) 51 is formed at one end of the cylindrical portion 40c, through which the annular gap 50 and the cylindrical internal space 44 communicate in the radial direction. It is good to have a size that does not restrict the flow too much. As another modification, the communication path 51 may be a round hole, and furthermore, the communication path 51 may be a slit formed at one end of the small diameter portion 43b of the seat union 43.

In addition, the seat union 43 has a communication path 5 at the minimum diameter portion 43a.
The diameter is small at the position corresponding to 1 (a fin d is formed,
A bottom portion 40a of the aperture member 40 is located at one end on the side of the minimum diameter portion 43a.
A collision surface 52 is formed parallel to this bottom portion 40a at a position apart from the bottom portion 40a.

Next, the operation will be explained based on the above-described configuration. When the pressure of the fluid in the servo valve side passage 12 becomes higher than that of the reaction force mechanism side passage 13 by operating the handle, the servo valve side passage 12
A part of the fluid flows through the communication passage 17 to the reaction mechanism side passage 1.
It flows to 3. At this time, the fluid flows through the first flow path 34. Minimum diameter hole 31
．． Orifice 4ob, space 40d, annular gap 50. The communication path 51 flows into the second flow path 35 via the cylindrical internal space 44 . The fluid is compressed in the orifice 40b and the annular gap 5o, expands in the space 40d and the cylindrical internal space 44, and the pressure of the fluid decreases in multiple stages.

The fluid whose flow velocity is increased by the orifice 40b and whose pressure has decreased collides with the collision surface 52 to recover the pressure, thereby preventing the pressure from greatly decreasing and causing cavitation. The annular gap 50 is an orifice 40
Compared to b, the wetted area of the fluid can be larger,
By increasing the wetted area of the fluid, cavitation can be suppressed even when the back pressure is low.

<Effects of the Invention> As described above, the present invention includes a cup-shaped aperture member and a seat union that are fitted into a small diameter hole and a large diameter hole formed in a housing, respectively, and a cylindrical portion of the aperture member that is fitted into the seat union. A minimum diameter portion forming an annular gap with the large diameter hole, a small diameter portion forming a cylindrical internal space with the large diameter hole, and a large diameter portion fitting into the large diameter hole are continuously formed, and the sheet A collision surface is formed at one end of the union on the side of the smallest diameter hole at a position away from the bottom of the throttle member, on which the fluid from the orifice collides at right angles, and the annular gap and the cylindrical internal space are connected to the throttle member or the seat union. Since the communication path is formed in the radial direction, the pressure of the fluid can be recovered by the collision surface, and the occurrence of cavitation can be suppressed. Further, by increasing the wetted area of the fluid with the annular gap, the occurrence of cavitation can be suppressed. As a result, it is possible to suppress the occurrence of cavitation as a whole, and it is possible to obtain the advantage that the generation of noise due to cavitation can be suppressed.

[Brief explanation of drawings]

゛The drawings show an embodiment of the present invention. Fig. 1 is a cross-sectional view of the fluid restricting device, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line -■ in Fig. A cross-sectional view taken along the line -■, and FIG. 4 is a diagram in which the fluid restricting device is applied to a power steering device. 30...Housing, 31...Minimum diameter hole, 32...
・Small diameter hole, 33...Large diameter hole, 40...Aperture member, 4
0a...bottom, 40b...orifice, 40c...
・Cylindrical part, 40d...Space, 43...Seat union, 43a...Minimum diameter part, 43b...Small diameter part, 43
c...Large diameter portion, 44...Cylindrical internal space, 50.
...Annular gap, 51...Communication path, 52...Collision surface.

Claims (1)

[Claims] (1) A minimum diameter hole, a small diameter hole communicating with the pump, and a large diameter hole communicating with the fluid equipment are formed in succession in the housing, and a throttle member having a cup shape consisting of a cylindrical part and a bottom part and an orifice formed in the bottom part is attached to the bottom part. is fitted into the small diameter hole with the cylindrical portion of the aperture member forming an annular gap, and the seat union is fitted into the large diameter hole with the smallest diameter portion facing the smallest diameter hole side, and the seat union is fitted into the large diameter hole. A small diameter part that forms a cylindrical internal space and a large diameter part that fits into the large diameter hole are continuously formed. A fluid restrictor characterized in that a collision surface is formed at which the fluid from the orifice collides at right angles at the position, and a communication path is formed in the restrictor member or the seat union in the radial direction to communicate the annular gap and the cylindrical internal space. Device.