JPH11201212A - Damping valve of hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance a height accuracy between adjacent valve seat surfaces to provided a stable damping characteristic and to enhance a degree of freedom of tuning by easily changing a shape of a difference in level, a height, etc., between the valve seat surfaces. SOLUTION: A seat plate 34 is secured to an edge of a piston 25 which is sintering-molded. A slit opening 44 constituting a valve hole is formed on the seat plate 34. A valve plate 35 and a spacer plate 36 are overlapped and secured at the center portion of an upper surface of the seat plate 34. An annular set plate 43 is disposed on an outer periphery of an upper surface of the seat plate 34. A total height of the valve plate 35 and the spacer plate 36 becomes the same as a height of the annular set plate 43. A slit plate 37 and valve plates 38, 39 are overlapped and secured to the spacer plate 36 and a lower surface of the slit plate 37 is abutted against an upper surface of the annular set plate 43.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping valve used for a hydraulic shock absorber, and more particularly, to a damping valve in which a disc valve is provided in a plurality of stages in a valve body which divides the inside of the shock absorber into a plurality of liquid chambers. About.

[0002]

2. Description of the Related Art As this kind of damping valve, a damping valve as shown in FIG. 13 has been conventionally developed.

The damping valve 1 has a communication hole 5 for communicating an upper chamber 3 and a lower chamber 4 with a piston 2 as a valve body.
Is formed, and at the end of the piston 2 on the lower chamber 4 side,
An annular first valve seat surface 6 and a second valve seat surface 7 having a diameter larger than that of the first valve seat surface 6 are formed in a stepped shape. ,
A first disc valve 8 and a second disc valve 9 which are respectively in contact with the second valve seat surfaces 6 and 7 are mounted via a spacer 10 and a nut 11. The rigidity of the first disc valve 8 is set to be small, and the rigidity of the second disc valve 9 is set to be large. The orifice groove 1 is provided in the second valve seat surface 7 in contact with the second disc valve 9.
2 are formed. Therefore, the orifice groove 12 and the second disc valve 9 act in parallel, and these and the first disc valve 8 act in series. Reference numeral 13 denotes a spring that urges the outer peripheral edge of the second disk valve 9 toward the second valve seat surface 7 to increase the rigidity of the second disk valve 9.

Since the damping valve 1 is constructed as described above, the first disk valve 8 and the orifice groove 12 are provided while the operating speed of the piston 2 is very low and the flow rate of the liquid passing through the communication hole 5 is small. When the operating speed of the piston 2 increases and the flow rate of the liquid passing through the communication hole 5 increases, the outer peripheral edge of the second disc valve 9 separates from the second valve seat surface 7 and the damping force is generated. The damping force is generated in the valve 9.

[0005] The entire area including the first and second valve seat surfaces 6, 7 of the piston 2 forming the valve body of the damping valve 1 is integrally formed by sinter molding.

Incidentally, this related technique is disclosed in, for example,
No. 47250, etc.

[0007]

However, the above-mentioned conventional damping valve 1 has a first valve seat surface 6 forming a step.
And the second valve seat surface 7 are formed integrally with the piston 2 by sintering, so that the sintering becomes a neck and the height from the first valve seat surface 6 to the second valve seat surface 7 is high. It cannot be raised above the value. Therefore,
The second valve seat surface sintered and formed with respect to the height of the support portion on the center side of the second disk valve 7 in which a plurality of plates 8, 9, and 10 having high molding accuracy are stacked on the end surface of the piston 2. 7 greatly varies, and as a result, the initial set pressure at the outer peripheral edge of the second disk valve 9 varies, making it difficult to obtain a stable damping force at the second disk valve 9.

In the conventional damping valve 1, since the first valve seat surface 6 and the second valve seat surface 7 are integrally formed by sintering, the stepped shape, height and the like of the two seat surfaces 6, 7 are formed. In the case of changing sintering, it is necessary to remanufacture the sintering mold itself, and there is a disadvantage that the degree of freedom of tuning is low.

Therefore, the present invention improves the height accuracy between adjacent valve seat surfaces, and can easily change the step shape, height, and the like between the adjacent valve seat surfaces, thereby achieving stable operation. An object of the present invention is to provide a damping valve of a hydraulic shock absorber that can secure a damping force and improve a degree of freedom of tuning.

[0010]

According to a first aspect of the present invention, there is provided a sinter-molded valve body having an annular valve seat surface abutting a disk valve at an end of a valve body. In a damping valve of a hydraulic shock absorber provided in a plurality of stages, a step portion between adjacent valve seat surfaces is formed by a plate separate from the valve body. The plate can be easily formed with high precision by a method other than sinter molding. The specifications of the step portion can be easily changed by appropriately changing the punching shape, size, thickness, and the like of the plate to be used.

A second aspect of the present invention is a damping valve for a hydraulic shock absorber having a plurality of annular valve seat surfaces abutting a disc valve at an end of a valve body to be formed by sintering. A first valve seat surface is provided at an end portion, and an annular set plate having a predetermined height whose end surface forms a second valve seat surface is disposed at an outer peripheral portion of the first valve seat surface. A first disk valve having an outer diameter smaller than the inner diameter of the annular set plate and an overall height being equal to or less than the height of the annular set plate and a spacer plate are overlapped and fixed to the center of the spacer plate. The second disk valve whose portion abuts on the end face of the annular set plate is fixed. The height between the first valve seat surface and the second valve seat surface is determined by the height of the annular set plate. Since the annular set plate is separate from the valve body, it can be easily and accurately formed by a method other than sinter molding.

According to a third aspect of the present invention, in the second aspect of the present invention, a plurality of centering projections are provided on the outer peripheral surface of the first disk valve so as to be in contact with the inner peripheral surface of the annular set plate. The annular set plate is centered on the valve body via the centering projection and the first disc valve.

According to a fourth aspect of the present invention, in the second aspect of the present invention, a plurality of centering projections are provided on the inner peripheral surface of the annular set plate so as to be in contact with the outer peripheral surface of the first disk valve.

According to a fifth aspect of the present invention, in the second aspect of the present invention, a plurality of centering projections are provided on the outer peripheral surface of the annular set plate so as to be able to contact the inner peripheral surface of the cylindrical wall extending from the valve body. I did it. The annular set plate is centered on the valve body via the centering protrusion and the cylindrical wall.

According to a sixth aspect of the present invention, in the second aspect of the invention, a plurality of centering projections are provided on the inner peripheral surface of the cylindrical wall extending from the valve body so as to be able to contact the outer peripheral surface of the annular set plate. I did it.

According to a seventh aspect of the present invention, there is provided the valve body according to any one of the second to sixth aspects, wherein the seat plate has an arc-shaped slit opening as a valve hole and the upper surface of which forms the first valve seat surface. And fixed on the end face. The slit opening of the sheet plate can be easily formed by punching or the like by press working, and the opening area and formation position of the slit opening can be easily changed.

According to an eighth aspect of the present invention, in the seventh aspect, the outer diameter of the slit opening of the seat plate is larger than the inner diameter of the seat portion at the end face of the valve body and smaller than the outer diameter of the seat portion. Was set to. The pressure receiving surface of the first disk valve is set to be radially outside the inner diameter of the seat portion of the valve body.

According to a ninth aspect of the present invention, in the seventh or eighth aspect, the outer diameter of the seat plate is formed to be larger than the outer diameter of the seat portion on the end face of the valve body. The inner diameter of the annular set plate disposed on the outer peripheral edge of the end face of the seat plate is set to be larger than the outer diameter of the seat portion of the valve body, so that the pressure receiving area of the second disk valve can be expanded radially outward. Become.

According to a tenth aspect of the present invention, in any one of the seventh to ninth aspects, a notch is formed in the seat plate so as to extend from the slit opening to a radially outer side of the first disk valve. The notch formed in the seat plate functions as a constant orifice communicating when the first disc valve is closed.

[0020]

Next, an embodiment of the present invention will be described with reference to the drawings. In each of the embodiments, common portions are denoted by common reference numerals, and description of overlapping portions will be omitted.

First, a first embodiment will be described with reference to FIGS.

FIG. 2 shows a strut-type hydraulic shock absorber adopting the damping valve according to the present invention. The hydraulic shock absorber has a free piston 22 inside a cylinder 21 whose upper end is connected to the vehicle body side. The liquid chamber 23 is separated from the gas chamber 24 by the gas chamber 24.
While being separated into an upper chamber 23A and a lower chamber 23B, a distal end of a piston rod 26 extending downward from the piston 25 is connected to a wheel support member (not shown) such as a knuckle via an outer cylinder 27 and a bracket 28. Is joined to. The piston 25 includes an extension-side damping valve 20A that generates a damping force while allowing the liquid to flow from the upper chamber 23A to the lower chamber 23B when the piston rod 26 is displaced in the extension direction, and a piston rod 26 that contracts. Contraction-side damping valve 2 that generates a damping force while permitting the flow of the liquid from the lower chamber 23B to the upper chamber 23A when displaced in the direction.
0B, these valves 20A, 20B
The damping valve according to the present invention is employed. The contraction-side damping valve 20 arranged above the piston 25
B and the extension-side damping valve 20A disposed on the lower side are arranged upside down, but are substantially identical in structure, and the piston 25 is connected to both damping valves 20B and 2B.
It constitutes a valve body of 0A. In the following, only the contraction-side damping valve 20B disposed above the piston 25 will be described.

As shown in FIGS. 1 and 3, the piston 25 is formed with a plurality of communication holes 29a, 29b, which communicate the upper chamber 23A and the lower chamber 23B. The remaining half 29b is used as a passage for flowing the liquid from the lower chamber 23B to the lower chamber 23B. The former communication passage 29a is used for the contraction side damping valve 20B, and the latter communication passage 29b is used for the extension side damping valve 20A (see FIG. 2). Further, a seat portion 30 is provided at the upper end of the piston 25 so as to protrude in a substantially wavy shape along the outer peripheral region. The seat portion 30 separates the former communication passage 29a and the latter communication passage 29b from each other. Has become. Further, a boss portion 31 having the same height as the seat portion 30 is provided in a central region of the upper end portion of the piston 25, and a communication passage 2 is provided between the boss portion 31 and the seat portion 30.
An annular groove 32 opening 9a is formed. Boss part 3
A through hole 33 is provided at the center of the piston rod 1 along the axial direction, and the small diameter portion 26a of the piston rod 26 is fitted into the through hole 33. The piston 25 is entirely formed by sintering.

The small diameter portion 26 of the piston rod 26
The distal end of the small-diameter portion a protrudes upward from the boss portion 31. As shown in FIG. 3, the small-diameter portion 26a protrudes into the seat plate 34, the valve plate 35, the spacer plate 36, the slit plate 37, and the valve plate 38. ,
39, spacer put 40, washer 41 (see FIG. 1)
Are sequentially fitted, and these are fastened and fixed to the upper surfaces of the boss portion 31 and the sheet portion 30 by a nut 42 screwed to the tip of the small diameter portion 26a. Also, valve plate 3
An annular set plate 43 having a height equal to or less than the total height thereof is disposed in the outer peripheral region of the spacer 5 and the spacer plate 36.
The upper and lower surfaces of the annular set plate 43 are sandwiched between the outer peripheral edges of the slit plate 37 and the sheet plate 34.

The seat plate 34 has an outer diameter substantially equal to the maximum outer diameter of the seat portion 30 of the piston 25, and has three arc-shaped slit openings 44 on a circumference of a predetermined diameter.
Are formed at equal intervals. The seat plate 34 is in close contact with the boss portion 31 of the piston 25 and the upper surface of the seat portion 30, and the slit opening 44 communicates with the annular groove 32 and the communication passage 29a to form a valve hole. The upper surface 34a of the seat plate 34 constitutes the first valve seat surface in the present invention.

The valve plate 35 has a slit opening 44.
The slit opening 44 is formed to have a larger outer diameter than that of the slit opening 44, and the slit opening 44 is closed from the upper surface side in an initial state where no hydraulic pressure acts on the slit opening 44 portion. This valve plate 35 constitutes a first disk valve in the present invention. The spacer plate 36 is formed to have an outer diameter slightly smaller than the outer diameter of the boss 31 of the piston 25, and when a predetermined pressure or more is applied to the pressure receiving surface on the lower surface side of the valve plate 35, the spacer plate 36 Warp deformation on the upper side of the outer peripheral edge portion is allowed. An annular set plate 4 is provided on the outer peripheral surface of the valve plate 35.
A plurality of centering projections 45 that can be brought into contact with the inner peripheral surface of the projection 3 are provided at equal intervals in the circumferential direction, and the centering projection 45 centers the annular set plate 43 with respect to the piston 25.

The upper surface 43 of the annular set plate 43
“a” constitutes the second valve seat surface in the present invention.

Slit plate 37 and valve plate 3
8 and 39 are formed to have substantially the same outer diameter as the annular set plate 43, and these three plates 37, 38 and 39 form a set to constitute the second disk valve of the present invention. The valve plates 38 and 39 are formed of simple annular plates, but the slit plate 37 is formed with a plurality of slits 37a that open radially outward on the outer peripheral edge of the annular plate at equal circumferential intervals. ing. The slit 37a forms an orifice groove (constant orifice) between the upper surface 43a of the annular set plate 43 and the valve plate 38.
The cut reaches at least to the inside of the inner diameter of the annular set plate 43.

The spacer plate 40 is formed to have a slightly smaller outer diameter than the boss portion 31 of the piston 25, and when the liquid pressure equal to or higher than the set pressure acts on the pressure receiving surface on the lower surface side of the slit plate 37, the spacer plate 40 is separated from the slit plate 37. Upward warpage of the outer peripheral edges of the valve plates 38 and 39 is allowed.

The above plates 34 to 40 and 43 are all formed by subjecting a plate material formed by rolling or the like to high precision by punching or the like by press working, and as a first disk valve. The rigidity of the valve plate 35 is small, and the total rigidity of the slit plate 37 as the second disk valve and the valve plates 38 and 39 is set large.

Since the damping valve 20B is configured as described above, when the piston 25 is displaced downward at a very low speed in the cylinder 21, the pressure-raised liquid in the lower chamber 23B passes through the slit opening 44 of the sheet plate 34. It acts on the lower surface of the valve plate 35 to warp and deform the outer peripheral edge of the valve plate 35 to create a gap between the valve seat 35 and the seat plate 34. Then, at this time, the liquid flows through the gap, further flows into the upper chamber 23A through the slit 37a of the slit plate 37, and generates a damping force at the valve plate 35 and the slit 37a.

When the piston 25 is displaced downward in the cylinder 21 at a speed higher than a predetermined speed, the pressure of the liquid in the lower chamber 23B is increased by the outer peripheral edge of the valve plate 35, and further by the slit plate 37 and the valve plate 38. , 39 are warped and the liquid flows into the upper chamber 23A through the gaps formed by the deformation of the plates 35, 37 to 39. At this time, the slit plate 37 and the valve plates 38, 39
Is greater than the rigidity of the valve plate 35, the damping force is mainly generated at the slit plate 37 and the valve plates 38 and 39.

In the damping valve 20B, the stepped portion between the seat surface of the valve plate 35 and the seat surface of the slit plate 37 is formed in an annular set plate 43 separate from the piston 25 formed by sintering. , The height of the sheet surface with which the slit plate 37 abuts can be set with high accuracy, and the height is higher than that of the conventional one in which the seat surface and the step portion are formed integrally with the piston. Accuracy is significantly improved. That is, in the related art, the height accuracy of the seat surface cannot be increased beyond a certain value due to an error caused by sintering as a bottleneck. However, in this damping valve 20B, an annular set separate from the piston 25 is provided. By providing the plate 43, the height of the sheet surface can be accurately set with high accuracy without being affected by errors due to sintering. Therefore, in the case of the damping valve 20B, the dispersion of the initial set pressure of the slit plate 37 and the like is extremely reduced, and as a result, stable damping characteristics can be reliably obtained.

Further, in the damping valve 20B, since the seat surface of the damping valve 20B which is in contact with the slit plate 37 is formed by the annular set plate 43 separate from the piston 25, the plate thickness, size, punching shape and the like of the annular set plate 43 are provided. By changing the parameters, it is possible to easily cope with different specifications, and there is an advantage that the degree of freedom of tuning is improved. Further, since the same piston 25 can be used for a damping valve having only one valve seat surface or a type having three or more valve seat surfaces, cost reduction by mass production effect can be realized. is there.

In this damping valve 20B,
Since a plurality of centering projections 45 are provided on the outer peripheral surface of the valve plate 35 and the centering projections 45 allow the annular set plate 43 to be centered with respect to the piston 25, the manufacturing cost does not significantly increase. Despite having a simple structure, it is possible to reliably prevent the contact surface between the slit plate 37 and the annular set plate 43 from shifting, so that the attenuation characteristics can be stabilized also from this surface. In this embodiment, the centering projection 45 is provided on the outer peripheral surface of the valve plate 35. However, the outer peripheral surface of the valve plate 135 is provided on the inner peripheral surface of the annular set plate 143 as in the second embodiment shown in FIG. The same effect can be obtained by forming a plurality of centering protrusions 145 that can be brought into contact with the surface.

Next, a third embodiment will be described with reference to FIGS.

FIG. 5 shows a damping valve 220 according to the present invention.
2A and 2B show a strut type hydraulic shock absorber adopting A and 220B, which is different from that shown in FIG. 2 and is disposed outside a cylinder 221 for accommodating a piston 225. Between the outer cylinder 227 and the reservoir chamber 46
Is formed, and the reservoir chamber 46 and the lower chamber 223B in the cylinder 221 communicate with each other via the base valve 47. The hydraulic shock absorber allows the piston 225 to extend the damping valve 220A that generates a damping force when the piston rod 226 extends, and allows the liquid to flow from the lower chamber 223B to the upper chamber 223A during the contracting operation. A check valve 48A is provided, and the base valve 47 controls the flow of the liquid from the reservoir chamber 46 to the lower chamber 223B when the piston rod 226 generates the contraction-side damping valve 220B that generates a damping force when the piston rod 226 contracts. An allowable check valve 48B is provided. The distal end of the piston rod 226 is connected to the vehicle body via an insulator rubber (not shown), and the lower end of the outer cylinder 227 is connected to a wheel-side member via a bracket 28.

FIGS. 6 and 7 show the damping valve 220A on the piston 225 side.
A is different from that of the first and second embodiments shown in FIGS.
A cylindrical wall 50 that is in sliding contact with the inner wall of the cylinder 221 is integrally formed on the outer periphery of the one end portion by sinter molding.
Although the cylindrical wall 50 itself has a well-known structure, a damping valve 220A is arranged on the inner peripheral side of the cylindrical wall 50.
In the case of this damping valve 220A, the annular set plate 2
A plurality of centering projections 245 are formed on the outer peripheral surface of the cylindrical set 43 so as to be in contact with the inner peripheral surface of the cylindrical wall 50.
3 is centered on the piston 225.

This damping valve 220A can basically obtain the same operation and effect as those of the first and second embodiments described above. However, a centering projection 245 is formed on the outer peripheral surface of the annular set plate 243. The centering projection 245 is provided with a piston 225 having a sufficient height and thickness.
The centering of the annular set plate 243 is further ensured because the cylindrical set 50 is brought into contact with the cylindrical wall 50. still,
In this embodiment, a plurality of centering protrusions 245 are formed on the outer peripheral surface of the annular set plate 243, but conversely, a plurality of centering protrusions that can contact the outer peripheral surface of the annular set plate 243 are formed inside the cylindrical wall 50. Even if it is formed on the peripheral surface, substantially the same effect can be obtained.

Further, a fourth embodiment will be described with reference to FIGS.

In this embodiment, the basic structure is shown in FIGS.
21. The difference is that the first disk valve abutting on the upper surface of the seat plate 34 has a configuration in which the slit plate 60 and the valve plate 135 are overlapped. The slit plate 60 and the valve plate 135 have the same outer diameter, and a pair of slits 60a that open radially outward are formed on the outer peripheral edge of the slit plate 60. The slit 60a is provided between the upper surface of the seat plate 34 and the valve plate 1.
An orifice groove (constant orifice) is formed between the slits 35, and the cut length is set so as to reach at least the slit opening 44 of the sheet plate 34. Further, in the case of this embodiment, the height of the annular set plate 243 is set to be equal to or greater than the total height of the slit plate 60, the valve plate 135, and the spacer plate 36 which are superimposed.

The damping valve of this embodiment can basically obtain the same functions and effects as those of the first to third embodiments, but the seat plate 34 and the valve plate 13
5. A slit plate 60 defining an orifice groove between
The damping force by the slit 60a can be obtained when the piston 225 is displaced at an extremely low speed.

FIGS. 10 and 11 show a fifth embodiment. The damping valve of this embodiment is a further modification of the damping valve shown in FIGS.
A similar function can be obtained without using 0. That is, the damping valve of this embodiment includes a slit opening 344 and a slit opening 3
44, a notch 344a extending radially outward of the valve plate 135 is formed.
The notch 344a functions as an orifice groove (constant orifice) in a state where the abutment 35 contacts the sheet plate 334.

In the case of this damping valve, the seat plate 3
Since the function of the orifice groove can be obtained only by additionally forming the notch 344a in the groove 34, the number of parts is reduced as compared with those shown in FIGS. The notch 344a in the sheet plate 334 can be easily formed by punching or the like together with the slit opening 344 by press working, and the manufacturing cost is further increased in combination with the aforementioned reduction in the number of parts. Can be reduced.

The embodiment of the present invention is not limited to the one described above. For example, the end face of a valve body such as a piston may be used as the first valve seat face without the seat plate. However, when a sheet plate is used as in the embodiment described above, the first
Since the processing accuracy of the valve seat surface can be increased, and the slit opening serving as the valve hole can be easily formed by punching or the like, it is easy to change the opening position and the opening area of the valve hole. There are advantages.

In addition to this, as shown in FIG. 12, the outer diameter φB of the slit opening 44 formed in the seat plate 34 is the outer diameter φD of the seat portion 30 of the piston 225.
, For example, φC <φB <φD (however,
Since φC can be freely set like the inner diameter of the seat portion 30, the pressure receiving area of the valve plate 135 (first disc valve) can be increased without being restricted by the inner diameter φC of the seat portion 30 of the piston 225. Can be.
Also, as shown in FIG.
If A is set to be larger than the inner diameter φC of the seat portion 30 of the piston 225, the diameter of the annular set plate 243 is expanded radially outward without being restricted by the inner diameter φC of the seat portion 30 of the piston 225, and the slit plate 37 ( The pressure receiving area of the second disc valve) can be increased. Therefore, in such a case, the degree of freedom of tuning is further increased.

[0047]

As described above, according to the first aspect of the present invention, the step between the adjacent valve seat surfaces is formed by a plate separate from the valve body to be sintered and molded. The step portion that determines the height between the sheet surfaces can be easily and accurately formed by a method other than sinter molding, and the specification of the step portion can be easily changed, as a result, It is possible to secure a stable damping force by reducing the variation such as the valve opening pressure of the second disk valve due to the variation in the height of the valve seat surface, and to provide a degree of freedom in tuning the attenuation characteristics and the like. Also increase. Further, since the step portion is formed by a plate separate from the valve body, the valve body of the damping valve having only one valve seat surface, which has been widely used conventionally, can be diverted as it is. As a result, the production efficiency can be greatly improved.

According to a second aspect of the present invention, a first valve seat surface is provided at an end portion of the valve body, and an annular portion having a predetermined height and an end surface forming a second valve seat surface is formed on an outer peripheral edge of the first valve seat surface. A set plate is provided, and a first disk valve and a spacer plate having an outer diameter smaller than the inner diameter of the annular set plate and an overall height equal to or less than the height of the annular set plate are provided at the center of the first valve seat surface. Since the second disc valve whose outer peripheral edge is in contact with the end face of the annular set plate is fixed to the end face of the spacer plate, the height of the second valve seat face is set with high accuracy. , The initial set pressure (valve opening pressure) of the second disk valve can be accurately set, and the punching shape, size, height, etc. of the annular set plate can be changed. Therefore, it is possible to easily change the design.

According to the third to sixth aspects of the present invention, the annular set plate can be reliably centered on the valve body by the centering projection in the second aspect of the present invention.
It is possible to obtain more stable damping characteristics by keeping the seating position of the dick valve constant.

According to a seventh aspect of the present invention, in any one of the second to sixth aspects of the present invention, a seat plate having an arc-shaped slit opening as a valve hole and having an upper surface forming a first valve seat is provided. Since it is placed and fixed on the end face, a slit opening serving as a valve hole can be easily formed by punching a sheet plate or the like. In addition, by changing the opening area and formation position of the slit opening, the first disc valve can be formed. The attenuation characteristics can be easily changed.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the outer diameter of the slit opening of the seat plate is larger than the inner diameter of the seat portion on the end face of the valve body and smaller than the outer diameter of the seat portion. As a result, the pressure receiving surface of the first disk valve is expanded radially outward from the inner diameter of the seat portion of the valve body, and the damping force generated by the first disk valve can be set smaller.

According to a ninth aspect of the present invention, in the invention of the seventh or eighth aspect, the outer diameter of the seat plate is formed to be larger than the outer diameter of the seat portion on the end face of the valve body. Is set larger than the outer diameter of the seat portion of the valve body, so that the pressure receiving area of the second disk valve can be expanded radially outward, and as a result, the degree of freedom in tuning the second disk valve increases. .

According to a tenth aspect of the present invention, in any one of the seventh to ninth aspects, a notch is formed in the seat plate to extend from the slit opening to the outside in the radial direction of the first disk valve, and the notch is formed. Since the notch is made to function as a constant orifice, the molding of the constant orifice becomes easy, and the manufacturing cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part showing a first embodiment of the present invention.

FIG. 2 is an overall sectional view showing the embodiment.

FIG. 3 is an exploded perspective view of a main part showing the embodiment.

FIG. 4 is a plan view showing a second embodiment of the present invention.

FIG. 5 is an overall sectional view showing a third embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view showing the same embodiment, in which part F of FIG. 5 is turned upside down.

FIG. 7 is a plan view showing the embodiment.

FIG. 8 is an enlarged sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 9 is an exploded perspective view showing the same embodiment.

FIG. 10 is an enlarged sectional view of a main part showing a fifth embodiment of the present invention.

FIG. 11 is a plan view showing the embodiment.

FIG. 12 is an enlarged sectional view showing a modification of the third embodiment of the present invention.

FIG. 13 is a sectional view showing a conventional technique.

[Explanation of symbols]

20B, 220A: Damping valve, 25, 225: Piston (valve body), 30: Seat portion, 34, 334: Seat plate, 34a, 334a: Upper surface (first valve seat surface), 35, 135: Valve plate (No. 1) a spacer plate; 36 a spacer plate; 37 a slit plate (second disk valve); 38, 39 a valve plate (second disk valve); 43, 143, 243 a circular set plate; (Valve seat surface), 44, 344: slit opening, 45: centering projection, 50: cylindrical wall, 344a: notch.

Claims (10)

[Claims] 1. An end of a valve body to be sintered and formed,
In a damping valve of a hydraulic shock absorber having a plurality of annular valve seat surfaces in contact with a disc valve, a step portion between adjacent valve seat surfaces is formed by a plate separate from the valve body. Hydraulic damper damping valve. 2. An end of a valve body to be sintered and formed,
In a damping valve of a hydraulic shock absorber having a plurality of annular valve seat surfaces in contact with a disc valve, a first valve seat surface is provided at an end of a valve body, and an outer peripheral portion of the first valve seat surface is provided at an outer peripheral portion of the first valve seat surface. An annular set plate having a predetermined height whose end surface forms a second valve seat surface, and having an outer diameter smaller than the inner diameter of the annular set plate and having an overall height in the center of the first valve seat surface. The first disk valve and the spacer plate, which have a height equal to or less than the height of the plate, are fixed by overlapping, and the second disk valve whose outer peripheral edge is in contact with the end surface of the annular set plate is fixed to the end surface of the spacer plate. Hydraulic damper damping valve. 3. The hydraulic shock absorber according to claim 2, wherein a plurality of centering projections are provided on an outer peripheral surface of the first disk valve so as to be able to contact an inner peripheral surface of the annular set plate. Damping valve. 4. The hydraulic shock absorber according to claim 2, wherein a plurality of centering projections are provided on an inner peripheral surface of the annular set plate so as to be in contact with an outer peripheral surface of the first disc valve. Damping valve. 5. A plurality of centering projections provided on the outer peripheral surface of the annular set plate, the plurality of centering projections being able to contact the inner peripheral surface of a cylindrical wall extending from the valve body.
3. The damping valve of the hydraulic shock absorber according to claim 1. 6. A plurality of centering projections provided on an inner peripheral surface of a cylindrical wall extending from a valve body, the plurality of centering projections being capable of contacting an outer peripheral surface of an annular set plate.
3. The damping valve of the hydraulic shock absorber according to claim 1. 7. A seat plate having an arc-shaped slit opening as a valve hole and having an upper surface forming a first valve seat surface is mounted and fixed to an end surface of a valve body. The damping valve of the hydraulic shock absorber according to any one of the above. 8. The seat plate according to claim 7, wherein the outer diameter of the slit opening of the seat plate is set to be larger than the inner diameter of the seat portion on the end face of the valve body and smaller than the outer diameter of the seat portion. Hydraulic damper damping valve as described 9. The damping valve for a hydraulic shock absorber according to claim 7, wherein the outer diameter of the seat plate is formed larger than the outer diameter of the seat portion at the end face of the valve body. 10. The hydraulic shock absorber according to claim 7, wherein a notch extending from the slit opening to a radial outside of the first disk valve is formed in the seat plate. Damping valve.