JP3191229B2 - Damping valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a damping valve used for a hydraulic shock absorber.

[0002]

2. Description of the Related Art As is well known, a hydraulic damper mounted on a vehicle or the like is designed to generate a desired damping force. For example, a structure as shown in FIG. In the hydraulic shock absorber of the above, an orifice O formed by stamping or the like that guarantees a damping force in a low speed range of the piston speed when the hydraulic shock absorber is operated on the extension side, and a damping force in a medium speed region of the piston speed is also guaranteed. And a damping valve B formed of an annular leaf valve.

Therefore, the damping characteristic of the damping mechanism composed of the orifice O and the damping valve B is shown in FIG.
As shown in FIG. 6, the attenuation characteristic G appears as a composite of the orifice characteristic o indicated by the broken line and the valve characteristic b indicated by the dashed line.

However, in the case of this damping characteristic G, the change at the point of change (point g in FIG. 20) at which the orifice characteristic o of the square characteristic changes to the valve characteristic b of the proportional characteristic becomes sharp, When this is manifested in a vehicle hydraulic shock absorber, there is a problem that the ride comfort of the vehicle is adversely affected.

Therefore, in order to correct the above problem,
For example, there has been proposed a damping valve V as shown in FIG. 21 according to British Patent No. 966137.
Describes that a valve body V1 composed of a leaf valve has a plurality of slits V2 extending radially from the center thereof.

When the slit V2 is formed, a plurality of fan-shaped bent portions V3 are formed in the valve body V1, and a damping force of valve characteristics is generated when the bent portion V3 is bent. I have.

In the damping valve V, the outer peripheral side of the valve body V1 is set to a fixed portion V4.

Therefore, according to the proposal, in the low-speed range of the piston speed, the hydraulic oil from the upstream flows to the downstream side through the slit V2 formed in the damping valve V, and the piston speed reaches the middle-high speed range. Then, the slit V2 is expanded and the bent portion V3 is bent.

As a result, the damping force of the orifice characteristic is generated when the hydraulic oil passes through the slit V2, and the damping force of the orifice characteristic is gradually eliminated by the gradual expansion of the slit V2. .

On the other hand, since the bending portion V3 gradually bends, the damping force of the valve characteristic is gradually generated, and the orifice characteristic o as shown in FIG. There is an advantage that it is possible to prevent a sudden change mode at the change point g from being caused.

[0011]

However, in the proposal of the damping valve V according to the above-mentioned British patent, there is a fear that the damping valve V itself may be expensive.

That is, the slit V2 of the damping valve V needs to be formed as narrow as possible in width, that is, the gap is small. Since this is performed by processing, a slit is also punched and formed when the valve is punched and formed.

However, the slit V2 is formed by pressing.
In the case of forming by punching, there is a problem that the gap of the slit V2 cannot be narrowed technically.

Therefore, according to the technology such as electric discharge machining, it is possible to form the slit V2 having a narrow gap. However, in practice, it becomes necessary to prepare a control system for electric discharge machining or the like. There is an inconvenience that the manufacturing apparatus becomes complicated and large.

Further, in the case of electric discharge machining or the like, it takes more time to manufacture compared to press working, and the productivity of the damping valve V is reduced, and the damping valve V itself becomes expensive. There is an inconvenience.

The present invention has been made in view of the above circumstances, and has as its object the purpose of the present invention to provide a smooth transition point without causing a sudden change mode at a change point from the orifice characteristic to the valve characteristic. It is possible to generate the damping force of the damping characteristic, and it is most suitable for use in the hydraulic shock absorber for vehicles without incurring the productivity and cost increase. It is to provide a damping valve.

[0017]

In order to achieve the above-mentioned object, a damping valve according to the present invention is constructed by stacking a plurality of leaf valves, and at the time of stacking, from the center to the outer periphery. A plurality of slits extending radially are formed, and each leaf valve has one or more cutouts on its inner peripheral side while its outer peripheral end is a fixed part, and It is assumed that each leaf valve has one or a plurality of shielding portions that shield the notch of the adjacent leaf valve while forming the slit.

If necessary, it is assumed that an orifice communicating with the slit is formed at the center or near the center of the damping valve.

Preferably, rotation preventing means for preventing horizontal rotation of a plurality of leaf valves housed in an appropriate housing section in a stacked state is provided between the leaf valve and the housing section.

[0020]

Therefore, by laminating a plurality of leaf valves, a damping valve is formed, and at the time of lamination, a plurality of slits extending radially from the center toward the outer peripheral side are formed.

The width of the slit, that is, the gap can be adjusted not by directly changing the gap of the slit, but by adjusting the width of the notch or the shield in each leaf valve.

Further, the rotation preventing means for preventing horizontal rotation of a plurality of leaf valves housed in an appropriate housing portion in a laminated state is provided between the leaf valve and the housing portion. , The width of the slit, ie,
The gap is permanently maintained, and the generation of the damping force as originally set becomes possible permanently.

On the other hand, in the damping valve, when the piston speed is in a low speed range, the hydraulic oil from the upstream side, which is the high pressure side, flows out to the downstream side, which is the low pressure side, through a slit formed in the reduction valve.

When the piston speed escapes from the low speed range to the middle speed range, the shielding portion of each leaf valve forming the slit gradually bends.
The slit gradually expands to allow passage of hydraulic oil.

At this time, the orifice characteristic that has been exhibited by the passage of the hydraulic oil through the slit is gradually eliminated by the gradual expansion of the slit, and the shielding portion of each leaf valve starts to flex gradually. As a result, the attenuation characteristic is gradually converted into a proportional characteristic.

As a result, a smooth transition from the orifice characteristic to the proportional characteristic is realized, and a rapid characteristic change from the orifice characteristic to the proportional characteristic does not occur.

When an orifice is provided at the center of the damping valve, when the piston speed is in a low speed range, the hydraulic oil from the upstream flows to the downstream through the orifice. .

At this time, the damping force of the orifice characteristic required when the piston speed is in a low speed range is reduced as a whole, that is, a soft damping force can be generated.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The hydraulic shock absorber shown in FIG. 1 will be described below with reference to an embodiment shown in FIG. 1. The hydraulic shock absorber shown in FIG.
It is the one equipped on the part.

That is, when the piston 2 in the cylinder 1 slides on the extension side in the upward direction as viewed in the drawing, the hydraulic oil in the rod-side oil chamber R1 formed in the cylinder 1 causes the damping valve 10 to move. The hydraulic oil in the piston-side oil chamber R2 flows into the piston-side oil chamber R2 when the piston 2 in the cylinder 1 moves downward on the pressure side in the downward direction in FIG. It is formed so as to flow into the rod-side oil chamber R1 via the damping valve 10.

The piston 2 is interposed in the front spigot portion 3a of the piston rod 3, and the piston rod 3
Is fixed at a predetermined position by a piston nut 4 screwed into the distal end thread portion 3b.

The piston nut 4 is formed with a chamber 4a which opens toward the piston side oil chamber R2, and the piston rod 3 is connected to the rod side oil chamber R1 while communicating with the chamber 4a. The communicating port 3c is opened, and the vessel chamber 4a and the rod-side oil chamber R1 are communicated via the port 3c.

The piston nut 4 has the damping valve 10 disposed at the open end 4b, which is the lower end in the drawing, so as to close the chamber 4a.

The damping valve 10 is disposed at the open end 4b, and has an outer peripheral end portion as a fixed portion 10a, and a pair of washers 5 adjacent from above and below.
And is fixed at a predetermined position while being pinched.

The damping valve 10 includes a plurality of, ie, two leaf valves 11 and 12 in the illustrated example, and when the two leaf valves 11 and 12 are stacked, the damping valve 10 is also shown in FIG. As shown, a plurality of radially extending from the center toward the outer peripheral side, that is, in the illustrated example, four slits 10b are formed, and an orifice 10c is formed at the center thereof. It is going to be.

The arrangement of the orifice 10c may be omitted. However, if the orifice 10c is formed as in the embodiment, when the piston speed is in a low-speed range, the orifice 10c is provided from the upstream side. The hydraulic oil flows downstream through the orifice 10c, and at this time, the damping force of the orifice characteristic required when the piston speed is in the low speed range is reduced as a whole, that is, soft damping is performed. There is an advantage that force can be generated.

Each of the leaf valves 11 and 12 in the illustrated example is formed by punching or the like from the same raw material as that conventionally provided as a so-called leaf valve.

That is, each of the leaf valves 11 and 12 is
As shown in FIG. 4 and FIG.
a, 12a, and a plurality of notches 11b, 12b in the example shown in the drawing, and two notches 11b, 12b of the adjacent leaf valve 11 or 12. 11b or 12b with the slit 10
It has a plurality of shielding portions 11c and 12c for shielding while forming b, that is, in the illustrated example.

Further, in this embodiment, each of the leaf valves 11 and 12 is provided at the center thereof with the cutouts 11b and 12b.
It has orifice notches 11d and 12d that form the orifice 10c while communicating with b.

In each of the leaf valves 11 and 12, two notches 11b and 12b and two shields 11
c, 12c and the orifice cutouts 11d, 12d have the same shape and size, and are formed so as to be line-symmetric via a vertical line set outside.

However, comparing the areas of the cutouts 11b, 12b and the shields 11c, 12c in each leaf valve 11, 12, the area of the cutouts 11b, 12b is larger than the area of the shields 11c, 12c. It is set to be.

That is, in each of the leaf valves 11 and 12, the boundary between the notch portions 11b and 12b and the shielding portions 11c and 12c is appropriately set with respect to the cross center line shown by imaginary lines in FIGS. The gap is set so as to be eccentric with a gap, that is, a gap of half the gap dimension of the slit 10b.

As a result, when the leaf valves 11 and 12 are stacked, the notch portions 11b and 12b and the shielding portion 11
The slit 10b is formed by the boundary line between c and 12c.

Further, by changing the amount of eccentricity with respect to the cross center line, the gap size of the slit 10b can be changed.

Each of the leaf valves 11 and 12 is arranged such that the leaf valves 11 and 12 are accommodated in an appropriate accommodating portion in a stacked state, that is, in the illustrated example, at the open end 4 b of the piston nut 4. , 12 are provided with appropriate rotation preventing means in order to prevent the horizontal rotation and maintain the correlation angle.

That is, the rotation preventing means includes chamfered portions 11e, 12e (see FIGS. 3 and 4) formed at a part of each leaf valve 11, 12 which becomes the lower end of the fixed portions 11a, 12a in the drawing. A chamfered portion 4c (FIG. 2) provided at the opening end 4b to be adjacent to the chamfered portions 11e and 12e.
See).

Incidentally, the rotation preventing means is provided with the chamfered portion 11.
Although not shown, instead of the chamfering structure including the chamfered portions 4e and 12e and the chamfered portion 4c, a protrusion and a recess into which the protrusion is fitted are provided between the piston nut 4 side and each of the leaf valves 11 and 12 side. The fitting structure may be set.

Therefore, in the damping valve 10 formed as described above, the two cutouts 11b and 12b in each leaf valve 11 and 12 are only formed by stamping by press working. A desired damping valve 10 is formed when the layers 11 and 12 are laminated, and a plurality of slits 10b having a gap of a desired size at the time of laminating, that is, four slits 10b are radially formed from the center of the damping valve 10 toward the outer periphery. It can be formed to be extended.

That is, it is not necessary to directly form the slit 10b having a narrow gap size in the damping valve 10.

In the illustrated example, each leaf valve 1
The orifice cutouts 11d, 1
When the damping valve 10 is formed by laminating the leaf valves 11 and 12, the orifice 10c communicating with the slits 10b is formed at the center thereof.

As a result, for example, in FIG. 1, when the piston 2 rises in the cylinder 1 and the rod-side oil chamber R1 is on the high pressure side, and when the piston speed is in the low speed range, Then, the hydraulic oil from the high pressure side passes through the slit 10b of the damping valve 10 and flows out to the piston side oil chamber R2 as the low pressure side, and at this time, a damping force having a predetermined orifice characteristic is generated.

When the orifice 10c is formed at the center of the damping valve 10 as in the embodiment, the hydraulic oil from the high pressure side flows out through the orifice 10c to the low pressure side. The damping force at this time is lower than the damping force obtained when the hydraulic oil passes through the slit 10b, that is, a soft damping force.

When the piston speed escapes from the low speed range and becomes equal to or higher than the medium speed range, as shown in FIGS. 5 and 6,
Each leaf valve 11, 1 forming the slit 10b
2, the shielding portions 11c and 12c gradually bend, that is, the slit 10b gradually expands, thereby allowing the passage of hydraulic oil.

At this time, the operating oil has been
b, the orifice characteristic developed by passing through the slits 10b is gradually eliminated by the gradual expansion of the slit 10b, and the shielding portions 1 in the leaf valves 11 and 12 are removed.
As 1c and 12c gradually begin to bend, the damping characteristic is gradually converted to a proportional characteristic.

As a result, a smooth transition from the orifice characteristic to the proportional characteristic is realized, and a rapid characteristic change from the orifice characteristic to the proportional characteristic does not occur.

In a situation where the slit 10b gradually expands, the orifice 10c also gradually expands, and the orifice characteristics up to that point are gradually eliminated. 11d,
By gradually bending 12d, the damping force of the orifice characteristic up to that point is gradually converted to the damping force of the proportional characteristic.

The above is the same, for example, when the piston 2 descends in the cylinder 1 in FIG. 1 and the piston side oil chamber R2 is on the high pressure side.

However, in the case where the rigidity of each of the two leaf valves 11 and 12 is set to be different from that of the other in the damping valve 10, for example, when the rigidity of each of the two leaf valves 11 and 12 is set to be different. The damping force on either the extension side or the compression side becomes higher or lower.

Even if the rigidity of the two leaf valves 11 and 12 is set to be the same, the so-called support point is changed by setting the inner diameters of the pair of upper and lower washers 5 differently. As a result, the damping force on either the extension side or the compression side becomes higher or lower.

FIG. 7 shows another embodiment of the leaf valve constituting the damping valve 10. The leaf valve 13 according to this embodiment has a fixed portion 13a, a cutout portion 13b and a shielding portion 13c. However, the notch 13
It is assumed that b is one place and the shielding part 13d is also one place.

In this embodiment, an orifice notch 13d for forming the orifice 10c is formed at the center of the leaf valve 13.

In the case of this embodiment, as shown in FIG. 8, the damping valve 10 having four slits 10b is constituted by stacking a plurality of, ie, four, leaf valves 13.

In this embodiment, since each leaf valve 13 has a notch 13d for orifice at the center thereof, the orifice 10c is formed at the center of the damping valve 10. Become.

As is clear from the above embodiment, the damping valve 10 of the present invention is only required to be formed by laminating two or more leaf valves, and it is not necessary to limit the number. That is to say.

Although not shown, the number of slits 10b formed in the damping valve 10 is not limited, and may be five or more as in the above-described conventional example. Instead of the example, slit 1
0b may be three or two.

FIG. 9 shows a damping valve 10 according to another embodiment.
In the damping valve 10 according to this embodiment, it is assumed that the damping valve 10 in each of the above-described embodiments is formed at another portion instead of forming the orifice 10c at the center thereof. I have.

That is, the shielding portion 11c of the upper leaf valve 11, which forms one slit 10b, and the shielding portion 12c of the lower leaf valve 12, which forms the other slit, are both appropriately notched so that the damping valve 10 is formed. The orifice 10c is located at a portion other than the center, that is, near the center.
Is formed.

In the case of this embodiment, the damping valve 1
The orifice 10c may not be formed in the central portion of 0, or the orifice 10c may be left as it is, as shown by a broken line in the figure.

In the case where the orifice 10c is left in the center, the flow path area in the low speed region of the piston speed in the damping valve 10 is increased, and there is an advantage that a softer damping force can be generated.

The orifice 10c is
As described above, the arrangement may be omitted. For example, if the leaf valve constituting the damping valve 10 is formed like the leaf valve 13 shown in FIG. It is sufficient to deform one of the four leaf valves 13 laminated as in the leaf valve 14 shown in FIG.

That is, the leaf valve 14 is
a, notch 14b and shielding part 14c, but not having an orifice notch, and having a closing part 14d instead of the orifice notch. .

Therefore, when the leaf valve 14 is laminated with the leaf valve 13 shown in FIG. 7 to constitute the damping valve 10, the direction formed by the three leaf valves 13 as shown in FIG. The orifice 10b is concealed by the closing portion 14d formed in the leaf valve 14, so that the orifice can be omitted.

FIG. 12 shows another embodiment of the arrangement of the damping valve 10 in the piston 2 portion.
In this embodiment, the piston 2 is provided with the damping valve 10.

That is, the storage chamber 2a formed inside the lower end of the piston 2 so as to open to the piston side oil chamber R2 is closed by the damping valve 10 fixed to the opening end 2b. .

The chamber 2a and the rod-side oil chamber R1
Are communicated with the piston 2 through an open port 2c.

According to this embodiment, there is an advantage that the arrangement of the piston nut 4 (see FIG. 1) becomes unnecessary.

In the illustrated example, the communication between the chamber 2a and the rod-side oil chamber R1 is replaced with the port 2c formed by drilling the piston 2 in the same manner as in the embodiment shown in FIG. A port 3c (see an imaginary diagram in FIG. 12) may be formed in the shaft core portion on the tip side of.

FIGS. 13 to 15 show various embodiments of the arrangement of the damping valve 10 arranged on the piston nut 4 portion. In FIG. It is assumed that a pair of adjacent washers 5 is deformed.

That is, each of the pair of washers 5 has a valve stopper 5a. By changing the distance between the damping valves in the valve stopper 5a, the generation damping on the extension side or the compression side is performed. It will be possible to differ in power.

In the embodiment shown in FIG. 14, the arrangement of the pair of washers 5 is omitted, and instead, the cap 6 is screwed into the piston nut 4 so that the damping valve 10 The piston nut 4 has a valve stopper portion 4d, and the cap 6 also has a valve stopper portion 6d.
a.

In the case of this embodiment, there is an advantage that the crimping work becomes unnecessary and the assembling work becomes easy.

In the embodiment shown in FIG. 15, when a spring 7 for applying an initial load to the damping valve 10 is housed between the damping valve 10 and one of them, that is, the washer 5 located below in the figure. I do.

In the case of this embodiment, the damping valve 1
When 0 starts to bend due to the extension side operation, there is an advantage that the rising point of the damping force of the proportional characteristic is increased.

In each of the above-described embodiments, the damping valve 10 is disposed at the piston 2 portion. However, according to the structure of the present invention, the damping valve 10 is arranged as shown in FIG. Needless to say, it may be provided in the base valve portion 20 provided inside the lower end of the cylinder 1, and in this case, it is needless to say that the operation and effect do not differ.

In FIG. 16, reference numeral 21 denotes a valve case, which is fixed at a predetermined position by sandwiching the damping valve 10 with a pair of vertically adjacent washers 5 interposed therebetween.

Reference numeral 22 denotes a valve block for holding the valve case 21; 8 denotes a bottom cap for holding the valve block 22 between the lower end of the cylinder 1; and 9 denotes an outer cylinder. 1 and reservoir room R3
Are formed.

By the way, what has been described so far is as follows.
Although the case where the damping valve 10 is set to be used for both extension and compression is taken as an example, below, the damping valve 10 is arranged on the piston 2 part and another damping arranged on the piston 2 part. A description will be given of a case where the extension damping valve is used together with the valve.

That is, the hydraulic shock absorber shown in FIG. 17 is formed such that a predetermined damping force is generated by a damping mechanism provided in the piston 2 when the piston 2 slides in the cylinder 1. The damping mechanism includes a first damping structure 30 formed to generate a predetermined damping force at least in a medium to high speed region of the piston speed, and a first damping structure 30 disposed in parallel with the first damping structure 30 to reduce the piston speed. A second damping force generated in the middle to high speed range from the range
And the damping structure 40 of FIG.

To explain a little, the first damping structure 30
Has a damping valve B composed of an annular leaf valve in the same manner as the above-described conventional hydraulic shock absorber (see FIG. 19). It is arranged so as to close the opening end on the piston side oil chamber R2 side.

The damping valve B is connected to the valve nut 3 by a spring 31 disposed between the valve body 3 and the piston nut 4.
2 and is urged from the so-called back pressure side.

The piston 2 has a compression-side port 2e opened. The opening end of the compression-side port 2e on the rod-side oil chamber R1 side is closed by the non-return valve 34 in the presence of the non-return spring 33. It is said that.

In the illustrated example, the formation of the orifice O formed by stamping in the seat portion of the non-return valve 34 in the piston 2 is omitted, but the orifice O is formed as shown by a broken line in the figure. You may.

On the other hand, the second damping structure 40 is provided at the piston nut 4 and is provided with the second damping structure 4.
0 has the damping valve 10 described above.

Piston nut 4 part and damping valve 10
Is similar to that of the above-described embodiment shown in FIG. 1 and subsequent figures, and therefore, only the reference numerals are given in the figure, and detailed description thereof is omitted.

The chamber 4a formed in the piston nut 4 and opened in the shaft core of the piston rod 3 is connected to the rod-side oil chamber R.
In this embodiment, the port 3c communicating with No. 1 is the first port.
Rod-side oil chamber R1 that bypasses the damping structure 30 of FIG.
And a so-called bypass passage that communicates with the low pressure side piston-side oil chamber R2.

Therefore, in the hydraulic shock absorber according to this embodiment, for example, in FIG. 17, when the piston 2 rises in the cylinder 1 and the rod-side oil chamber R1 is on the high-pressure side, The hydraulic oil from the rod-side oil chamber R1 flows out through the first damping structure 30 and the second damping structure 40 to the piston-side oil chamber R2 on the low pressure side.

That is, when the piston speed is assumed to be in the low speed range, the hydraulic oil is supplied to the slit 10 b (or the orifice 10) of the damping valve 10 in the second damping structure 40.
When c is formed, it flows through the orifice 10c) and flows out to the piston side oil chamber R2, and at this time, the slit 10b (or the orifice 10c) generates an extension side damping force having a predetermined orifice characteristic. Is done.

In the first damping structure 30, the orifice O formed by stamping the seat portion of the non-return valve 34.
Is formed, the hydraulic oil passes through the orifice O in the low-speed region of the piston speed, and in this case, the hydraulic oil passes through the orifice 10c in the second damping structure 40. In addition, a lower, that is, softer, damping force on the extension side is generated in the low-speed range of the piston speed.

When the piston speed escapes from the low speed range to the middle speed range, the hydraulic oil from the rod side oil chamber R1 flows out to the piston side oil chamber R2 via the damping valve B in the first damping structure 30. At this time, an extension damping force having predetermined valve characteristics is generated.

At the same time, when the piston speed comes out of the low speed range and becomes the middle speed range, the hydraulic oil from the rod side oil chamber R1 receives the respective leaf valves 11 and 12 constituting the damping valve 10.
Of the shield portions 11c and 12c (see FIG. 2) at the inner peripheral side, and flows out to the low pressure side. At this time, the extension side damping force having a predetermined proportional characteristic is generated. Become.

In this case, the slit 10
b, the shielding portions 11c and 12c in each of the leaf valves 11 and 12 gradually bend, that is, the slit 10b gradually expands, and the orifice characteristics up to that point are gradually eliminated. Since the shielding portions 11c and 12c of the leaf valves 11 and 12 gradually begin to bend, the damping force of the orifice characteristic up to that time is gradually converted to the damping force of the proportional characteristic.

As a result, even if the damping valve B in the first damping structure 30 which did not operate until the piston speed escapes from the low speed range to the middle speed range suddenly starts operating, the second damping structure will not operate. Since a smooth transition from the orifice characteristic to the proportional characteristic is realized by 40, a sudden characteristic change from the orifice characteristic to the proportional characteristic is not exhibited.

Conversely, when the piston 2 descends in the cylinder 1 and the piston side oil chamber R2 is set to the high pressure side, the hydraulic oil from the piston side oil chamber R2 is subjected to the first damping. The fluid flows into the rod-side oil chamber R1, which is a low-pressure side, via the non-return valve 34 in the structure 30.

In the embodiment shown in FIG. 17 described above, the structure of the piston nut 4 provided with the second damping structure 40 is different from that of the illustrated example in the embodiment shown in FIGS. Needless to say, it may be configured as follows.

In the embodiment shown in FIG. 17, the damping valve 10 may be replaced with the embodiment shown in FIG.
Of course, it may be configured as shown in each embodiment of FIG.

FIG. 18 shows an embodiment of a hydraulic shock absorber in which the first damping structure 30 and the second damping structure 40 are arranged in the base valve section 20.

That is, the hydraulic shock absorber is provided in the valve case 21.
It is assumed that the valve case 21 has a first damping structure 30 at a portion thereof, and the valve case 21 has a second damping structure 40 at a portion of a valve block 22 at which the valve case 21 is fixed to an axial center portion thereof.

The first damping structure 30 includes a damping valve 35 composed of an annular leaf valve and a valve block 22.
The open end of the compression-side port 22a is closed so as to close the open end of the expansion-side port 22b of the valve block 22 with the non-return valve 37 being urged by the non-return spring 36. It is arranged so that it does.

On the other hand, the second damping structure 40 is formed so that the damping valve 10 closes the chamber 21a formed in the valve case 21 and opening to the piston side oil chamber R2. The valve 10 includes a valve case 21
Is fixed to the open end 21b of the first pair with the pair of washers 5 interposed therebetween.

The chamber 21a is provided in the valve case 2
One of the shaft cores is communicated with the lower side of the base valve section 20, that is, the reservoir chamber R3 side, through a through hole 21c formed by drilling.

Incidentally, also in this embodiment, the damping valve 1
Since 0 is the same as in each of the above-described embodiments, detailed description thereof is omitted.

Therefore, in the hydraulic shock absorber according to this embodiment, when the piston side oil chamber R2 is on the high pressure side, the hydraulic oil from the piston side oil chamber R2 is supplied to the first damping structure 30 and the second damping structure. Through the damping structure 40 to the reservoir chamber R3 which is a low pressure side.

That is, when the piston speed is in the low speed range, the hydraulic oil is supplied to the damping valve 1 in the second damping structure 40.
The slit 10b (or the orifice 10c in the case where the orifice 10c is formed) flows out to the reservoir chamber R3 through the slit 10b (or the orifice 10c). An extension damping force is generated.

In the first damping structure 30, the orifice 2 is formed by stamping the seat portion of the non-return valve 37.
When 2c is formed, the hydraulic oil passes through the orifice 22c in the low-speed region of the piston speed. In this case, the hydraulic oil is lower than the low-speed region of the piston speed.
That is, a softer pressure damping force is generated.

When the piston speed goes out of the low speed range to the middle speed range, the hydraulic oil from the piston side oil chamber R2 flows out to the reservoir chamber R3 through the damping valve B in the first damping structure 30. That is, at this time, an extension-side damping force having predetermined valve characteristics is generated.

At the same time, when the piston speed escapes from the low speed range to the middle speed range, the hydraulic oil from the piston side oil chamber R2 receives the respective leaf valves 11, 1 constituting the damping valve 10.
2, the inner ends of the shielding portions 11c and 12c (see FIG. 2) are bent so as to flow out to the low pressure side.
At this time, an extension-side damping force having a predetermined proportional characteristic is generated.

At this time, the slit 10
b, the shielding portions 11c and 12c in each of the leaf valves 11 and 12 gradually bend, that is, the slit 10b gradually expands, and the orifice characteristics up to that point are gradually eliminated. Since the shielding portions 11c and 12c of the leaf valves 11 and 12 gradually begin to bend, the damping force of the orifice characteristic up to that time is gradually converted to the damping force of the proportional characteristic.

As a result, even if the damping valve B in the first damping structure 30 which has not been operated until then when the piston speed escapes from the low speed region to the middle speed region suddenly starts to operate, the second damping structure Since a smooth transition from the orifice characteristic to the proportional characteristic is realized by 40, a sudden characteristic change from the orifice characteristic to the proportional characteristic is not exhibited.

On the contrary, when the piston side oil chamber R2 is on the low pressure side, the hydraulic oil from the reservoir chamber R3 is supplied to the piston side oil chamber R2 via the non-return valve 37 in the first damping structure 30. Flowed into.

In the embodiment shown in FIG. 18, the damping valve 10 is configured as shown in each embodiment of FIGS. 8, 9, and 11, as well as the embodiment shown in FIG. Of course, it may be.

[0121]

As described above, according to the present invention, a damping valve is formed by stacking a plurality of leaf valves, and at the time of the stacking, the damping valve extends radially from the center to the outer peripheral side. Since a plurality of slits are formed, there is an advantage that the formation of the slit is easier and more reliable than forming the slit directly in the attenuation valve.

The width of the slit, that is, the gap can be adjusted not by directly changing the gap of the slit, but by adjusting the width of the notch or the shield of each leaf valve.

Further, a rotation preventing means for preventing horizontal rotation of a plurality of leaf valves housed in an appropriate housing portion in a stacked state is provided between the leaf housing and the housing portion. , The width of the slit, ie,
The gap is permanently maintained, and the generation of the damping force as originally set becomes possible permanently.

On the other hand, in the damping valve, when the hydraulic oil from the high pressure side reaches the damping valve, when the piston speed is in a low speed range, the hydraulic oil flows to the low pressure side through a slit (orifice if there is an orifice). When the piston flows out to generate a damping force having a predetermined orifice characteristic, and when the piston speed escapes from the low speed region and becomes the middle speed region, the shielding portion in each leaf valve forming the slit gradually bends, that is, The slit gradually expands (and the orifice when there is an orifice) to allow the passage of hydraulic oil, gradually eliminates the orifice characteristics up to that point, and the shielding portion of each leaf valve is gradually bent. By starting, the damping characteristic is gradually converted to a proportional characteristic, and a smooth transition from the orifice characteristic to the proportional characteristic is performed. There is achieved an advantage that sharp characteristic change from the orifice characteristic to a proportional characteristics can not be expressed.

Further, by setting the rigidity of one leaf valve in the laminated state and the rigidity of the other leaf valve to be different from each other, the magnitude of the damping force when the hydraulic oil passes in one direction and the magnitude of the damping force in the opposite direction are reduced. There is an advantage that the magnitude of the damping force at the time of passage of the hydraulic oil can be set differently.

According to the present invention, the thickness of the damping valve itself can be extremely reduced, and as a result, the form of the damping force generating portion such as the piston portion and the base valve portion in the hydraulic shock absorber can be reduced. It is possible to
Therefore, the oil chamber space in the hydraulic shock absorber can be increased, and the overall size of the hydraulic shock absorber can be reduced to improve mountability on a vehicle. There is an advantage that the effect is achieved.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing one embodiment of a piston portion in a hydraulic shock absorber equipped with a damping valve according to the present invention.

FIG. 2 is a cross-sectional view taken along line XX in FIG.

FIG. 3 is a plan view showing one leaf valve constituting the damping valve of FIG. 2;

FIG. 4 is a plan view showing another leaf valve constituting the damping valve of FIG. 2;

FIG. 5 is a sectional view showing an operation state of the damping valve of FIG. 2;

FIG. 6 is a plan view showing an operation state of the damping valve of FIG. 2;

FIG. 7 is a plan view showing another embodiment of the leaf valve constituting the damping valve.

8 is a plan view showing a damping valve constituted by the leaf valve of FIG. 7;

FIG. 9 is a plan view showing a damping valve according to another embodiment.

FIG. 10 is a plan view showing another embodiment of the leaf valve constituting the damping valve.

11 is a plan view showing a damping valve configured by laminating the leaf valve of FIG. 10 with a plurality of leaf valves of FIG. 7;

FIG. 12 is a partial longitudinal sectional view showing another embodiment of the arrangement of the damping valve in the piston portion, similarly to FIG.

FIG. 13 is a partial semi-sectional vertical sectional view showing another embodiment of the arrangement of the damping valve in the piston portion.

FIG. 14 is a partially half-sectional longitudinal sectional view showing another embodiment of the arrangement of the damping valve in the piston portion.

FIG. 15 is a partial half-section longitudinal sectional view showing another embodiment of the arrangement of the damping valve in the piston portion.

FIG. 16 is a partial longitudinal sectional view showing one embodiment of a base valve portion in a hydraulic shock absorber equipped with a damping valve according to the present invention.

FIG. 17 is a partial longitudinal sectional view showing one embodiment of a piston portion in a hydraulic shock absorber provided with a damping valve of the present invention together with another damping valve in a piston portion.

FIG. 18 is a partial longitudinal sectional view showing one embodiment of a base valve portion in a hydraulic shock absorber provided with the damping valve of the present invention together with another damping valve in the base valve portion.

FIG. 19 is a partial vertical sectional view showing a piston portion in a conventional hydraulic shock absorber having a valve structure.

20 is a diagram showing damping characteristics of the conventional valve structure of FIG.

FIG. 21 is a plan view showing a damping valve as a further conventional example.

[Explanation of symbols]

 4c Chamfering part constituting rotation prevention means 10 Damping valve 10b Slit 11, 12,... Leaf valve 11a, 12a,... Fixed part 11b, 12b,... Sections 11e and 12e Chamfering sections constituting rotation preventing means

Claims (3)

(57) [Claims] 1. A plurality of leaf valves are laminated, and a plurality of slits are formed radially extending from the center toward the outer periphery at the time of the lamination, and each leaf valve has an outer peripheral end. One or more notches on the inner peripheral side thereof with the portion as a fixed portion, and each leaf valve shields the notch of an adjacent leaf valve while forming the slit, and one or more notches. Damping valve characterized by having a shielding part 2. The damping valve according to claim 1, wherein an orifice communicating with the slit is formed at a central portion or near the central portion. 3. The damping valve according to claim 1, wherein rotation preventing means for preventing horizontal rotation of a plurality of leaf valves housed in an appropriate housing part in a stacked state is provided between the leaf valves.