CN101571176B

CN101571176B - Plate valve

Info

Publication number: CN101571176B
Application number: CN2008100943433A
Authority: CN
Inventors: 网仓俊哉
Original assignee: Kayaba Industry Co Ltd
Current assignee: KYB Corp
Priority date: 2008-04-28
Filing date: 2008-04-28
Publication date: 2011-01-19
Anticipated expiration: 2028-04-28
Also published as: CN101571176A

Abstract

The invention provides a plate valve. A platy valve body (16) and annular valve seats (17, 20) for placing the valve (16) form a one-way valve (10) used in a hydraulic buffer (1); a plurality of circles of vortex-shaped spiral grooves (17b, 20b) are formed on a placing surface of the value body (1) of the valve seats (17, 20); the spiral grooves (17b, 20b) are respectively opened at the inner sideand the outer side of the valve seat (17); the width of the spiral grooves (17b, 20b) is set into the width that is larger than the width of walls (17a, 20a) which are adjacent to the spiral grooves (17b, 20b); thus, when the valve body (16) ascends from the valve seats (17, 20), enough working oil is supplied to peeling parts of the valve body (16) and the valve seats (17, 20) from the spiral grooves (17b, 20b) so that the impact sound along with the peeling can be prevented.

Description

Sheet valve

Technical Field

The present invention relates to a flap valve for preventing generation of abnormal noise when the flap valve incorporated therein is opened in a hydraulic shock absorber used for a railway vehicle or the like.

Background

The check valve incorporated in the hydraulic shock absorber, for example, causes a disc-shaped valve body to be seated on an annular valve seat.

The hydraulic pressure in the hollow portion inside the annular valve seat acts on the valve body as a valve opening pressure, and the valve opening pressure is greater than the hydraulic pressure acting on the back surface of the valve body, so that the valve body rises from the valve seat and opens the check valve. The check valve having such a structure is used for, for example, allowing the working oil to flow into the cylinder from the oil reservoir outside the cylinder without resistance when the piston accommodated in the cylinder is operated toward the expansion side.

In a large hydraulic shock absorber used for a railway vehicle or the like, the operation of the check valve having such a structure is a factor of generation of abnormal noise.

That is, when the valve is closed, the valve body is attracted to the valve seat by an attracting force due to the viscosity of the oil. The check valve in which the valve opening pressure acts on the closed state is performed, for example, when the stroke direction of the piston is changed. That is, in many cases, the valve opening pressure does not gradually rise but rapidly acts on the check valve.

When the valve body and the valve seat are instantaneously separated from each other with the valve body and the valve seat in contact with each other through an oil film, a negative pressure is generated in a space formed between the valve body and the valve seat due to separation. On the one hand, this negative pressure delays the detachment of the valve body from the valve seat, and on the other hand, at the moment when the valve body rises from the valve seat, a large pressure change is imparted to the detached portion.

This pressure change causes the piston rod and the outer cylinder of the damper to resonate, thereby generating an impact sound.

Disclosure of Invention

Accordingly, an object of the present invention is to prevent the occurrence of a knocking sound accompanying the opening operation of a flap valve used in a hydraulic shock absorber.

In order to achieve the above object, a disc valve for a hydraulic shock absorber according to the present invention includes a plate-shaped valve body, an annular valve seat for seating the disc valve, and a plurality of spiral grooves formed in a spiral shape on a seating surface of the valve seat, both ends of the spiral grooves are opened on an inner side and an outer side of the valve seat, respectively, and a width b of the spiral grooves is set to be larger than a width a of a wall adjacent to the spiral grooves.

The details of the present invention, as well as other features and advantages thereof, are set forth in the following description of the specification and are illustrated in the accompanying drawings.

Drawings

Fig. 1 is a longitudinal sectional view showing a main part of a hydraulic shock absorber according to the present invention.

Fig. 2 is a plan view showing a valve seat of the present invention.

Fig. 3 is a sectional view showing a main portion of the valve seat taken along the line III-III of fig. 2.

FIG. 4 is similar to FIG. 3, but shows the occurrence of problems resulting from the cutting of helical flutes.

Detailed Description

Referring to fig. 1 of the drawings, a hydraulic shock absorber 1 employing the present invention has a cylinder 3, and the cylinder 3 is coaxially vertically disposed within an outer cylinder 2. The interior of the cylinder 3 is divided into an upper oil chamber and a lower oil chamber 4 by a piston not shown. Working oil is sealed in each of these oil chambers. Further, an oil reservoir 5 for storing the working oil is provided between the outer tube 2 and the cylinder 3.

The hydraulic shock absorber 1 generates a damping force against the sliding of the piston in the cylinder 3. A seat valve 6 for causing the working oil to flow between the oil chamber 4 and the oil reservoir 5 in accordance with the sliding of the piston is provided at the bottom of the cylinder 3.

The seat valve 6 has a valve disk 7, a bolt 8, and a nut 14, the valve disk 7 being fixed to the bottom of the cylinder 3, the bolt 8 penetrating the center of the valve disk 7, and the nut being screwed to the bolt 8. A compression-side damping valve 9 and a check valve 10 are provided on the valve disk 7.

A space 11 is delimited at the bottom of the cylinder 3 by means of the valve disk 7. The space 11 is always in communication with the oil reservoir 5 by means of a slit 12 formed in the valve disc.

A plurality of passages 13 are formed in the valve disk 7, and these passages 13 guide the working oil in the space 11 to the check valve 10. The passages 13 are arranged along the outer circumference of the bolt 8 when viewed in the axial direction of the cylinder 3, and penetrate the valve disks 7, respectively.

A plurality of passages 15 are formed inside the passage 13, and these passages 15 guide the hydraulic oil in the oil chamber 4 to the compression side damping valve 9. The passages 15 are arranged along the circumference between the passage 13 and the bolt 8 in a state viewed from the axial direction of the cylinder 3, and penetrate the valve discs 7, respectively.

The compression-side damping valve 9 is provided on the outlet of the passage 15 facing the space 11. The compression side damping valve 9 is constituted by a leaf valve. The leaf valve is formed of a plurality of overlapped leaves, and when the hydraulic pressure in the space 11 is increased to a predetermined pressure or more by the hydraulic pressure in the passage 15, the outer peripheral portion of the leaf valve is elastically deformed downward, and the hydraulic oil in the oil chamber 4 flows from the passage 15 to the oil reservoir 5 through the space 11. The compression-side damping force is generated by the flow resistance at this time.

The check valve 10 is provided on an outlet of the passage 13 facing the oil chamber 4. The check valve 10 includes a valve body 16 fitted to the outer periphery of the nut 14, an annular valve seat 17 formed on the valve disk 7 and adapted to seat the outer periphery of the valve body 16, an annular valve seat 20 formed on the valve disk 7 and adapted to seat the inner periphery of the valve body 16, and a return spring 18 for elastically supporting the valve body 16 against the valve seat 17 and the valve seat 20. The valve seat 17 and the valve seat 20 are formed coaxially on the valve disk 7. An annular groove 21 is formed between the valve seat 17 and the valve seat 20. The passage 13 opens inside the groove 21.

A stepped portion 14a is formed on the nut 14. The valve body 16 is formed of a circular flap which is slidably supported on the lower outer periphery of the stepped portion 14a of the nut 14. The return spring 18 is constituted by a coil spring. The return spring 18 has a base end supported by the step 14a and a tip end abutting against the valve body 16. The step portion 14a also functions as a stopper for restricting displacement of the valve element 16 by a predetermined degree or more. A communication hole 19 is formed in the valve body 16, and the communication hole 19 is used to ensure communication between the oil chamber 4 and the passage 15 to the compression-side damping valve 9.

The valve seat 17 and the valve seat 20 are configured as follows.

In the check valve 10 in the open state, the valve body 16 is in a state of being adsorbed on the valve seat 17 and the valve seat 20 by an adsorption force due to viscosity of oil. When the piston housed in the cylinder 3 is switched from the contraction stroke to the expansion stroke, the check valve 10 in the closed state receives a valve opening pressure. Since the change in the stroke direction of the piston occurs in a short time, the pressure of the oil chamber 4 changes rapidly, and the valve opening pressure of the check valve 10 rises rapidly. When the valve element 16 is instantaneously pulled away from the valve seat 17 and the valve seat 20 by the valve opening pressure in a state where the valve element 16 is in contact with the valve seat 17 and the valve seat 20 via an oil film, a negative pressure is generated in a gap between the valve element 16 and the valve seat 17 and the valve seat 20, which is generated by the separation. On the one hand, this negative pressure delays the peeling of the valve element 16 from the valve seat 17 and the valve seat 20, and on the other hand, at the moment when the valve element 16 rises from the valve seat 17 and the valve seat 20, a large pressure change is given to the peeled portion. When the piston rod and the outer cylinder 2 of the hydraulic shock absorber 1 resonate due to the pressure change, a knocking sound is generated.

Referring to fig. 2, in order to smoothly peel the valve body 16 from the valve seat 17 and the valve seat 20 when the valve is opened, the check valve 10 of the present invention includes a spiral groove 17b and a spiral groove 20b, the spiral groove 17b is formed on a surface of the valve seat 17 facing an outer peripheral surface of the valve body 16, and the spiral groove 20b is formed on a surface of the valve seat 20 facing an inner peripheral surface of the valve body 16.

The spiral groove 17b is a single groove formed on the surface of the annular valve seat 17 so as to rotate several turns in a spiral shape. One end of the spiral groove 17b opens to the oil chamber 4 at the outer circumferential surface of the valve seat 17. The other end of the spiral groove 17b opens at the side of the valve seat 17 facing the groove portion 21.

The spiral groove 20b is a single groove formed by spirally rotating several turns on the surface of the annular valve seat 20. One end of the spiral groove 20b opens to the passage 15 at the inner circumferential surface of the valve seat 20. The passage 15 is always in communication with the oil chamber 4 via a communication hole 19. The other end of the spiral groove 20b opens at the side of the valve seat 20 facing the groove portion 21.

Referring to fig. 3, the width b of the spiral groove 17b is made larger than the width of the portion where the spiral groove 17b is not formed, in other words, the width a of the wall 17a of the valve seat 17. In addition, the width a of the wall 17a is made larger than zero. I.e. the wall 17a is given a flat portion. The expression is expressed by the following formula.

b＞a＞0

Similarly to the spiral groove 17b, the spiral groove 20b is also set with a relationship between the width a of the wall 20a and the width b of the spiral groove 20 b.

In principle, the width a of the

walls

17a and 20a may be set to zero. Referring to fig. 4, when the

spiral grooves

17b and 20b are formed by cutting the surfaces of the valve seat 17 and the valve seat 20, if the widths a of the

walls

17a and 20a are set to zero, the heights of the remaining

walls

17a and 20a cannot be set to be constant due to a machining error as a result of the cutting. Therefore, in practice, the width a of the

walls

17a and 20a needs to be set to a value greater than zero.

When the valve seat 17 and the valve seat 20 are formed as described above, the spiral groove 17b and the spiral groove 20b are always filled with the working oil in a state where the valve element 16 as a leaf valve is seated on the valve seat 17 and the valve seat 20. Therefore, even if the valve opening pressure suddenly acts on the valve body 16 when the piston changes the displacement direction from the contraction stroke to the expansion stroke, the working oil accumulated in the spiral groove 17b and the spiral groove 20b can be directly supplied to the separation surface between the valve body 16 and the valve seat 17 and the valve seat 20. Therefore, the negative pressure is not generated in the gap between the valve element 16 and the valve seat 17 and the valve seat 20 due to the peeling, and the valve element 16 portion smoothly rises from the valve seat 17 and the valve seat 20 with resistance. As a result, the hydraulic shock absorber can be prevented from generating a striking sound accompanying the rise of the valve body 16.

As described above, by making the width b of the helical groove 17b and the helical groove 20b larger than the width a of the wall 17a and the wall 20a, a large amount of the working oil can be stored in the helical groove 17b and the helical groove 20 b. On the other hand, by making the width b of the spiral groove 17b and the spiral groove 20b larger than the width a of the wall 17a and the wall 20a, the area of the valve body 16 peeled off from the valve seat 17 and the valve seat 20 is reduced. Therefore, with this restriction, when the valve element 16 is peeled off from the valve seat 17 and the valve seat 20, the working oil can be sufficiently supplied to the peeled surface.

The spiral groove 17b and the spiral groove 20b are formed by rotating several turns on the seat surfaces of the valve seat 17 and the valve seat 20. For example, if the spiral groove 17b or the spiral groove 20b is formed only 1 turn, the oil chamber 4 and the space 11 can communicate with each other via the spiral groove 17b or the spiral groove 20b even if the check valve 10 is in the closed state, and the check valve 10 cannot prevent the working oil from flowing from the oil chamber 4 to the space 11 when the pressure of the oil chamber 4 is higher than the pressure of the space 11. That is, the effect of the check valve 10 of preventing the reverse flow is impaired.

Therefore, in order to prevent the oil from flowing through the spiral groove 17b or the spiral groove 20b when the check valve 10 is closed, it is preferable to set both the spiral groove 17b and the spiral groove 20b to be sufficiently long. Therefore, at least several turns of the spiral groove 17b and the spiral groove 20b need to be formed on the valve seat 17 and the valve seat 20, respectively.

In the above embodiment, the valve seat 17 corresponds to the 1 st valve seat, and the valve seat 20 corresponds to the 2 nd valve seat.

As described above, according to the present invention, the generation of the impact sound accompanying the opening operation of the flap valve for the hydraulic shock absorber is prevented with a simple structure. Therefore, the present invention is particularly effective in preventing a large impact sound from being generated when the piston changes the stroke direction in a large hydraulic shock absorber for a railway vehicle.

The present invention has been described above with reference to specific embodiments, but the present invention is not limited to the above embodiments. It is possible for those skilled in the art to make various modifications or alterations to these embodiments within the technical scope of the claims.

For example, in the above-described embodiment, the flap valve of the present invention is applied to the check valve 10 provided on the seat valve 6 in the hydraulic shock absorber 1. Of course, the flap valve of the present invention may be applied to a check valve provided in the piston of the hydraulic shock absorber 1.

The embodiments of the invention may comprise exclusive properties or features as set out in the preceding claims.

Claims

1. A flap valve for use in a hydraulic shock absorber (1); wherein,

the disc valve has a plate-shaped valve body (16), annular valve seats (17, 20), and spiral grooves (17b, 20b),

the valve seats (17, 20) are used for the valve body (16) to be positioned,

the spiral grooves (17b, 20b) are formed in a spiral shape in a plurality of turns on the seating surface of the valve body (16) of the valve seats (17, 20);

both ends of the spiral grooves (17b, 20b) are opened at the inner side and the outer side of the valve seats (17, 20), respectively;

the width b of the spiral grooves (17b, 20b) is set to be larger than the width a of the walls (17a, 20a) adjacent to the spiral grooves (17b, 20 b).

2. A leaf valve according to claim 1, wherein the width of all the walls (17a, 20a) adjacent to the spiral groove (17b, 20b) is set to be larger than zero.

3. Flap valve according to claim 1, wherein the flap valve functions as a one-way valve (10).

4. A disc valve according to claim 3, wherein said check valve (10) further comprises a return spring (18) for biasing said valve body (16) towards said valve seats (17, 20).

5. A disc valve according to any one of claims 1 to 4, wherein the annular valve seats (17, 20) include a first valve seat (17) for seating an outer peripheral portion of the valve body (16) and a second valve seat (20) for seating an inner peripheral portion of the valve body (16), the first valve seat (17) being formed of a material having a specific shape and a specific shape; the disc valve has an annular groove portion (21) and a passage (13), the annular groove portion (21) is formed between the first valve seat (17) and the second valve seat (20), the passage (13) is opened in the groove portion (21), and the passage (13) is closed by placing the valve body (16) on the first valve seat (17) and the second valve seat (20).