JPH043139Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a fluid noise reduction structure for a hydraulic shock absorber, and in particular, the damping force in the low speed range of a piston rod is reduced by a control valve housed in the rod housing. The present invention relates to a structure for reducing fluid noise generated when oil passes through an orifice of the control valve in a hydraulic shock absorber that is configured to be changeable.

[Conventional technology]

In a hydraulic shock absorber formed so that the damping force of the piston rod in a low speed range can be changed by a control valve housed in a rod housing near the tip of the piston rod, the control valve has a plurality of orifices. In addition, near the tip of the piston rod where the orifice faces, there is a through hole that communicates the upper chamber in the cylinder with the inside of the rod housing, and the orifice is selectively opposed to the through hole. , so that the damping force generated in the piston portion can be changed. The control valve is formed so that the control rod inserted into the piston rod can be rotated by external operation, and the control rod can be rotated to a set rotation angle. Therefore, the damping force in the desired piston rod low speed range is adjusted.

[Problem that the invention attempts to solve]

In the hydraulic shock absorber formed as above,
In the low speed range of the piston rod, oil from the upper chamber in the cylinder flows into the rod housing, which is open to the lower chamber in the cylinder, through the orifice facing the through hole, but at this time, a sound called swiss noise is produced. Fluid noise may occur. This fluid noise not only does not provide any benefit when the hydraulic shock absorber expands and contracts, but also poses a problem in that it becomes a noise when used in situations where silence is required.

Therefore, in view of the above-mentioned circumstances, the present invention has been developed to provide a hydraulic shock absorber that can reduce fluid noise in a hydraulic shock absorber that is formed so that the damping force generated in the low speed range of the piston rod can be changed using an orifice. The purpose is to provide a noise reduction structure.

[Means for solving problems]

In order to solve the above problems, the structure of the present invention is
A piston rod is movably inserted into the cylinder via a piston part, and the piston part divides the cylinder into an upper chamber and a lower chamber. The piston rod is opened and closed via a valve provided at its outlet end, and the tip of the piston rod is provided with a hollow rod housing that opens into the lower chamber. A hollow control valve is rotatably housed inside the rod housing and communicates with the chamber, and the control valve is formed with a plurality of orifices that selectively communicate with the above-mentioned through holes. Therefore, in a hydraulic shock absorber that generates a damping force corresponding to the orifice facing the through hole, a collar facing the control valve is inserted into the rod housing to partition the inside of the control valve from the lower inside of the rod housing. Further, a lateral groove is provided on the upper surface of the collar, and an axial throttle is formed on the side surface of the collar to communicate with the lateral groove, thereby communicating the inside of the control valve with the lower part of the inside of the rod housing through the lateral groove and the throttle, and reducing fluid resistance. It is characterized by the fact that it generates

〔Example〕

Hereinafter, the present invention will be explained based on the illustrated embodiments.

As shown in the overall view of FIG. 1 and the partially enlarged view of FIG. 2, a hydraulic shock absorber 1 according to an embodiment of the present invention
The cylinder has a piston part 12 disposed at the tip spigot part 11a of a piston rod 11 inserted into the cylinder 10, and the piston part 12 divides the inside of the cylinder 10 into an upper chamber A and a lower chamber B. Therefore, the cylinder 10 of the piston portion 12
It is formed so that a desired damping force on the extension side or the compression side, or on both extension sides, is generated during internal sliding.
In this embodiment, although not shown, the compression damping force is generated at the base valve portion at the lower end of the cylinder 10.

The piston portion 12 generates a rebound damping force, and the piston portion 12 has a check valve 14 disposed so as to close the oil passage 13a of the piston body 13 from both sides.
and a stopper 16 having an expansion side valve 15 and adjacent to the check valve 14 from the outside;
It has a valve stopper 18 that approaches the expansion side valve 15 from the outside via a spacer 17, and a nut 19 that is screwed from the outside of the valve stopper 18 into a thread 11b formed on the outer periphery of the spigot part 11a. It is firmly fixed.

Therefore, during the extension stroke of the piston rod 11, the oil in the upper chamber A of the cylinder 10 causes the oil in the oil passage 13a to bend the outer peripheral end of the extension-side valve 15, causing the outer peripheral end of the valve 15 and the valve seat portion to flex. When it flows into the lower chamber B within the cylinder 10 through the gap formed between them, a desired rebound damping force is generated.

The hydraulic shock absorber 1 formed as described above includes a damping force adjustment mechanism 2 for changing the rebound damping force.
0 is equipped.

This damping force adjustment mechanism 20 is adapted to the piston rod 1.
The rod housing 21 is formed from the tip of the rod 1 to the inside near the tip, and a control valve 22 is provided inside the rod housing 21. The control valve 22 has a plurality of orifices 22a and 22b (see Fig. 2) with different diameters or different drilling positions, and the lower end of a control rod 23 is fixed to the upper end of the orifices 22a and 22b. be. The control rod 23 is inserted into a through hole 11c (see FIG. 1) formed in the axial center of the piston rod 11, and its upper end protrudes into the upper end connecting portion of the piston rod 11 (see FIG. 1). (See Figure 1).

An electric or hydraulic actuator (not shown) is connected to the protruding upper end of the control rod 23, and the control rod 23 can be rotated by rotating the actuator. control valve 22 at the lower end.
The rod housing 21 rotates within the rod housing 21.

When the control valve 22 is rotated, the plurality of orifices 22a and 22b formed in the control valve 22 pass through the vicinity of the tip of the piston rod 11 and the cylinder 10
It selectively faces a plurality of through holes 24 formed so as to communicate between the inner upper chamber A and the inside of the rod housing 21.

Therefore, when the orifice of the control valve 22, for example, the orifice 22a as shown in the figure, is positioned to face the through hole 24, the inside of the upper chamber A in the cylinder 10 when the piston rod 11 is in a low speed range. During its extension stroke, the oil will flow into the control valve 22 positioned within the rod housing 21 through the through hole 24 and orifice 22a. Then, the oil in the upper chamber A flows into the orifice 22.
When the piston rod passes through A and flows into the rod housing 21, that is, into the lower chamber B, a desired damping force in the low speed range of the piston rod 11 is generated, and the control valve 22 is rotated. When the orifice 24b is selected to face the through hole 24, the damping force is changed to a different extension-side damping force in the low speed range of the piston rod 11.

Control valve 2 formed as above
Conventionally, the rod housing 21 is supported from below by a cylindrical collar (not shown) press-fitted into the rod housing 21 to prevent it from falling off. A collar 25 made of a solid body formed into a shape is press-fitted, and the collar 25 is intended to prevent the control valve 22 from falling off.

As shown in FIG. 3, the collar 25 has a cross groove 25a serving as a horizontal groove on its upper surface, and a vertical groove 25b communicating with the cross groove 25a on its side surface.

Therefore, by press-fitting the collar 25 into the rod housing 21 facing the lower part of the control valve 22, the control valve 22
The inside is divided into the lower part of the rod housing 21, and the inside of the control valve 22 is separated by a collar 25.
The vertical groove 2 communicates with the inside of the rod housing 21 and the lower chamber B through the cross groove 25a and the vertical groove 25b.
5b is used as a throttle in the axial direction that generates fluid resistance, thereby controlling the control valve 22.
When the oil in the upper chamber A flows into the upper chamber A through the orifice 22a or 22b, the pressure is slightly increased, and then the oil flow from the cross groove 25a is converted by 90 degrees and flows into the vertical groove 25b, so the flow velocity energy is lost. Both of them work together to reduce the occurrence of fluid noise.

FIGS. 4 and 5 show other embodiments of the collar 25 described above, and the collar 25' is
It has a one-character groove 25a' as a horizontal groove on its upper surface, and a notch surface 25b' connected to the one-character groove 25a' on its side surface.
By using b' as an axial throttle that generates fluid resistance, there is an advantage that fluid noise can be further reduced compared to the collar 25 according to the embodiment described above.

Further, FIG. 6 shows another embodiment of the present invention, in which the rod housing 21
A plurality of collars 25 are press-fitted inside. This makes it possible to further reduce fluid noise compared to the case where a single collar 25 is press-fitted. Further, in this embodiment, a plurality of collars 25' shown in FIG. 3 are press-fitted into the rod housing 21, but instead of this, other collars 25' shown in FIGS.
It is also possible to press-fit the color 2 of both.
5 and 25' may be used together.

Note that the same symbols used in FIG. 6 as in FIGS. 1 and 2 indicate that the configuration is the same, but in this embodiment, the piston portion 12 is slightly modified. This is what is being done.

That is, a diagonal oil passage 13a' is bored in the piston body 13, and an expansion side valve 15' made of a plate valve is disposed at the lower end opening of the oil passage 13a'. The lower end of the spring 15'' is secured to a fastening fitting 26 which also serves as a valve housing. Also, a check valve 14 adjacent to the upper end opening of the oil passage 13a of the piston body 13
is energized by a non-return spring 14',
The upper end of the non-return spring 14' is engaged with a stopper 16'.

Therefore, in this embodiment as well, the damping force in the reduction region of the piston rod 11 is caused by the oil in the upper chamber A flowing through the through hole 24 and the orifice 22 opposite thereto.
This is generated when oil flows into the rod housing 21 positioned within the control valve 22 through the passage a or 22b.
By selecting the orifices 22a and 22b that face 4, the extension damping force can be changed. The inside of the control valve 22 is inside the lower rod housing 21, that is, the lower chamber B.
by a collar 25 or 25' press-fitted into the rod housing 21 so as to separate it from the
Since the pressure is increased to some extent when the oil flows in from the upper chamber A, fluid noise called so-called swiss noise can be reduced.

[Effect of idea]

According to the present invention, the collar is formed with a horizontal groove on the upper surface and an axial restriction that communicates with the horizontal groove and generates fluid resistance, so that oil flows from the upper chamber to the lower chamber through the axial restriction. When flowing,
The fluid resistance generated by this throttle increases the internal pressure inside the control valve. For this reason, the jet that has passed through the orifice is once ejected and collected in this highly pressurized chamber. Then, the oil flow is converted 90 degrees from the transverse groove along the axial restriction, so the flow velocity energy is lost, and the oil flows out from the axial restriction to the inside of the rod housing and the lower chamber at a velocity lower than the jetting velocity, resulting in a jet stream. It is possible to prevent the occurrence of swishing noise caused by fluid noise and eliminate fluid noise.

Moreover, according to the present invention, even in its structure,
It is sufficient to simply change the design of the collar that is press-fitted into the rod housing to prevent the control valve from falling off, and not only does it not require any other special parts, but it also causes a change in the machining process or an increase in the number of machining processes. There is no such disadvantage.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of a hydraulic shock absorber according to an embodiment of the present invention, Fig. 2 is a partially enlarged front view thereof, and Fig. 3 is a collar according to an embodiment of the present invention. 4 is a plan view showing a collar according to another embodiment, FIG. 5 is a sectional view taken along the line - in FIG. 4, and FIG. 6 is a hydraulic shock absorber according to another embodiment of the present invention. FIG. 3 is a front view similar to FIG. 2; Explanation of symbols: 1...Hydraulic shock absorber, 10...Cylinder, 11...Piston rod, 12...Piston portion, 20...Damping force adjustment mechanism, 21...Rod housing, 22...Control valve, 22
a, 22b...Orifice, 23...Control rod, 24...Through hole, 25, 25'...Collar, 25a...Cross groove as horizontal groove, 25a'...Single character groove as horizontal groove, 25b...For aperture vertical groove, 25
b'... Cutout surface for aperture, A... Upper chamber, B... Lower chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A piston rod is movably inserted into the cylinder via a piston part, and the piston part divides the cylinder into an upper chamber and a lower chamber, and the upper chamber and the lower chamber are different from each other. The piston rod is opened and closed via an oil passage provided in the piston and a valve provided at the outlet end of the oil passage.A hollow rod housing that opens into a lower chamber is provided at the tip of the piston rod, and the inside of the rod housing is connected to the piston rod. A hollow control valve is rotatably housed inside the rod housing, communicating with the upper chamber through a through hole formed in the horizontal direction, and the control valve has a plurality of holes selectively communicating with the through hole. In a hydraulic shock absorber that forms an orifice and generates a damping force corresponding to the orifice facing the through hole by rotation of the control valve, a collar facing the control valve is inserted into the rod housing and the control valve is closed. A horizontal groove is provided on the upper surface of the collar, and an axial throttle is formed on the side surface of the collar to communicate with the horizontal groove. A fluid noise reduction structure for a hydraulic shock absorber, characterized by communicating with the lower part of the inside of a housing and generating fluid resistance. (2) A fluid noise reduction structure for a hydraulic shock absorber according to claim 1, wherein the collar is press-fitted into a rod housing. (3) The fluid noise reduction structure for a hydraulic shock absorber according to claim 1, wherein one or more collars are press-fitted into the rod housing. (4) Registration of a utility model in which the collar consists of a solid body formed approximately in the shape of a drum, has a single-character groove on the top surface, and has a cutout surface for aperture connected to the single-character groove on the side surface. A fluid noise reduction structure for a hydraulic shock absorber according to claim 1. (5) The collar consists of a solid body formed in a substantially drum shape, and has a cross groove on the top surface and a longitudinal groove for aperture connected to the cross groove on the side surface. A fluid noise reduction structure of a hydraulic shock absorber according to scope 1.