JPS59113333A - Hydraulic buffer - Google Patents

Abstract

PURPOSE:To change a damping force characteristic in three stages by disposing a damping force generating mechanism including a disc valve assembly with a small-diameter spacer interposed therebetween on the piston rod side end surface of a piston for partitioning the interior of a cylinder into two oil chambers. CONSTITUTION:A piston 6 for partitioning the interior of a cylinder 1 into two oil chambers A, B is mounted on one end of a piston rod 5. A bottomed concave portion 5D is formed on the piston rod 5 in such a manner as to direct from the forward end portion to the base end and an orifice passage 32 opened to the oil chamber A is mounted on the concave portion 5D. An extension side damping force generating mechanism 31 is disposed between a retainer fitted in a small- diameter portion 5A of the piston rod 5 through a guide member 15. The mechanism 31 comprises a disc valve assembly composed of discs 33A-33D, wherein the discs 33A, 33B are spaced from each other by a small-diameter spacer 34 having notch grooves 34A... formed on the inner peripheral edge. Orifices 35 are formed on the outer peripheral edge of the disc 33A to function as a variable throttle passage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is designed to generate a damping force by hydraulic resistance force by displacing a piston-piston rod assembly consisting of a piston and a piston rod in a cylinder to the three-dimensional extension side and contraction side. The present invention relates to a hydraulic shock absorber.

A conventional hydraulic shock absorber is shown in Figs. 1 to 4. First, in FIG. 1, reference numeral 1 denotes a cylinder consisting of an inner cylinder IA and an outer cylinder IB. One end of the cylinder 1 is covered with a cap f2, and the other end is covered with a sealing member 3 and a rod. Guide 4 is attached. 5 indicates a piston rod, one end of which passes through the sealing member 3 and the rod guide 4 and is connected to the inner cylinder I of the cylinder 1.
It is positioned within A, and the other end is made to protrude outside of the cylinder I. One end of the piston rod 5 has an inner M
A slidable sister piston 6 is inserted into the IA. 1 to 1 inner cylinder IA? A tom member 7 is provided on the tom bag 2 side. An oil liquid as a working fluid is sealed inside the inner ffa IA, and the piston 6 and the bottom member 7 serve as advance defining members, and the inside of the inner cylinder IA is filled with three parts from the rod guide 4 side. It is divided into oil chambers A, B, and C.

Furthermore, an annular chamber is formed between the inner cylinder IA and the outer cylinder IB, and several oil liquid sealing parts and gas sealing parts E are formed between the cutom member 7 and the bottom cag 2. The passage 8 formed in the oil chamber C is in continuous communication with the oil chamber C. Then, when the piston 40 and the piston 5 enter the cylinder 1, the oil equivalent to the volume of the piston rod 5 entering the inner cylinder IA flows from the passage 8 into the oil sealing part Km, and the oil liquid enters the gas sealing part E. The piston rod 5 is configured to compensate for the entry volume of the piston rod 5 in order to compress the gas therein.

Next, in the piston 6 forming the advance defining member of -, a passage 9 communicating between the oil chambers A and B is bored in the axial direction, and on the side of the piston 6 facing the oil chamber A. An extension side damping force generating mechanism 10 is provided which generates a damping force in the oil flowing from the oil chamber A to the oil chamber B side via the passage 9 when the piston rod 5 is displaced to the extension side. On the other hand, an oil chamber 11 communicating between oil chambers R and C is also drilled in the tom 81i material 7, which is another advance defining member.
On the side facing the piston rod 5, there is a contraction side that generates a damping force on the oil flowing from the oil chamber B through the passage 11 and the oil chamber 01 passage 8 to the oil liquid side when the piston rod 5 is displaced to the contraction side. A damping force generating mechanism 12 is provided.

Therefore, the specific configuration of each of the oval reduction force generating mechanisms 10.12 will be explained.

First, as shown in an enlarged view in FIG. 2, the extension side damping force +XO is a first +m2
, gT3 *NE4 (Dr Isk 13A.

The disk pulp assembly 13 consisting of 13B, 13c, and 13D, and a retainer 14 that faces the piston 6 while sandwiching the Rkf'' disk pulp assembly 13 are generally configured. Small diameter portion 5 formed at the tip of the rod 5
Stock iJ installed by mating AK? The piston rod 5 is fitted into the dual-purpose strip inner member 15 so as to be displaceable in the axial direction of the piston rod 5. The guide member 15 is connected to one end of the piston rod 5.
The piston 6 is sandwiched and fixed between the piston rod and the caulked portion 5B formed at the tip of the piston rod, and the other end of the piston rod abuts against the step portion 5C of the piston rod 5, and rises in the radial direction from the north. A spring receiver 16 is provided between the rising portion and the outer circumferential surface of the protrusion 6A of the piston 6, and the spring receiver 16 also has the function of positioning the disc pulp assembly 13 in the radial direction. A spring 17 is tensioned between the piston 6 and the piston 6, and the spring 17 always urges the disk pulp assembly 13 and the retainer 14 toward the piston 6. For this reason, in the disk pulp assembly 13, the outer peripheral edge of the first disk 13A contacts the protrusion 6A of the piston 6, and the inner peripheral edge of the fourth disk 13D contacts the inner protrusion 14A of the taker 14. It is forced into contact. On the other hand, an outer protrusion 14B is formed on the retainer 14, and the outer protrusion 14B is slightly further away than the inner protrusion 14A so that it is normally spaced apart from the fourth disk 13D. The protrusion length is shortened. Further, the first disk 13A of the disk pulp assembly 13 is provided with one or more notched grooves 18 forming a fixed orifice on its outer peripheral edge, and the spring receiver 16 is also provided with one or more notched grooves 18 toward the piston 6 side. A notch groove 19 is provided. As a result, a flow path that constantly communicates between the oil chambers A and B is formed by the notch groove 19°18 and the passage 9, and the flow path area is the same as that between both ends of the notch groove 18 of the first disk 13A and the first disk. 13A
Determined by the wall thickness. Further, the retainer 14 is provided with an axial flow passage 20 between the inner circumference side protrusion 14A and the outer circumference side protrusion 14B.
The pressure in the oil chamber A can be applied from the flow path 20 to the side surface of the fourth disk 130 via the flow path 20.

Therefore, when the pressure inside the oil chamber A becomes high, the disk pulp assembly 13 is bent, and the outer circumferential portions of the first and fourth disks 13A and 13D are exposed to the protrusion 6A of the piston 6 and the retainer 14, respectively. Each disk 13A, 13B, 13C, 13 comes into contact with the protrusion 14B and uses the northern part as a fulcrum.
The inner peripheral edge of D is bent in the direction away from the protrusion 14A of the taker 14. As a result, the protrusion 14 of the retainer 14
A flow path is formed between A and the fourth disk 13D, and the oil in the oil chamber A also flows toward the oil chamber B through this flow path. This flow path has nine variable throttle passages whose flow path area changes depending on the differential pressure between the oil chambers A and B. in this way,
Provides flow resistance to the oil passing through 9 fixed throttle passages formed by notched grooves 18 formed in the first disc 13A and variable throttle passages formed by the contact and separation of the disc pulp assembly 13 with the retainer 14. This generates a damping force on the piston 6.

Next, as shown in FIG. 3, the contraction side damping force generation mechanism 12 is roughly composed of a disk pulp assembly 21 and a retainer 22, similar to the expansion side damping force generation mechanism 10 described above. Here, the disk pulp assembly 21 is composed of three disks, the first disk pulp assembly 21 being made of three disks, in order to generate a smaller damping force than the expansion side. Second
．． It is composed of third disks 21A, 21B, and 21C.

A spring receiver 23 is provided along the inner wall of the inner cylinder IA, and one end of the spring receiver 23 is fixed by being sandwiched between the inner cylinder IA and the tom member 7. There is. A plurality of cuts are provided in the axial direction of the portion of the spring receiver 23 extending along the cylinder IA, and by partially bending inward in the radial direction along the cuts, the large diameter portion 23A and the small diameter portion A portion 23B is formed. By providing the large diameter part 23A and the small diameter part 23B in the spring receiver 23 in this way, a flow path 24 is formed between them, and the small diameter part 23B allows the disk pulp assembly 21 and the retainer 22 to move in the radial direction. A spring 25 is tensioned between the folded portion and the retainer 22, and the spring 25 causes the retainer 22 and the disc pulp assembly 21 to move yJ? ) is constantly pressed against the arm member 7 side. And, the outer peripheral edge of the first disk 21A of the disk pulp assembly 21 is ? The third disk 2IC is brought into contact with a protrusion 7A formed in an annular shape on the tom member 7, and the inner peripheral edge of the third disk 2IC is brought into contact with an inner protrusion 22A of the retainer 22. Furthermore, retainer 2
2 is formed with an outer circumferential side protrusion 22B having a shorter protrusion length than the inner circumferential side protrusion 22A, and a flow path 26 is formed in the axial direction between each of the protrusions 22A and 22B. Furthermore, one or more notched grooves 27, which serve as fixed orifices, are formed on the outer peripheral edge of the first disk 21A. These structures themselves are basically the same as those of the extension-side damping force generation mechanism 10. When the pressure in the oil chamber B increases when the piston rod 5 enters the cylinder 1, first the flow path 24
The oil in the oil chamber B flows through the notch groove 27, and the flow path is narrowed by the flow path area of the notch surface 27, resulting in a fixed throttle passage, which generates a damping force against the piston 6, and the oil When the pressure in the chamber B reaches a predetermined pressure, the disc valve assembly 21 separates from the protrusion 22A of the retainer 22, forming a variable throttle passage, and the damping force applied to the piston 6 changes on the extension side. Damping force generation 4! , i[lo and functionally there is no particular difference.

In addition, 28 and 29 in Figure 1 indicate the piston rod 5, respectively.
The outer end of the cylinder 1 and the bracket attached to the muck f2 are shown.

The hydraulic shock absorber according to the prior art does not have the above-mentioned configuration, and has a bracket 28 on the vehicle body side and a bracket 29 on the vehicle body side.
are attached to the undercarriage side to buffer vehicle vibrations. Therefore, the piston 6 is connected to the piston rod 5.
When the oil chamber A is expanded, the pressure inside the oil chamber A increases.
The pressure inside oil chamber B decreases. When the displacement speed of the histone 6 is in a low speed range, the oil in the oil chamber A flows toward the oil chamber B through a fixed throttle passage formed by a notched groove 18 provided in the first disk 13A. Due to the flow resistance that sometimes occurs, a damping force is generated on the piston 6. In this case, since the flow area of the fixed throttle passage is small, the damping force characteristic exhibits a remarkable rise as shown in FIG. Then, the displacement speed of the piston 6 becomes 1st and 5th speed, and the differential pressure between the oil chambers A and B increases to the disc valve assembly 13.
When the spring force becomes thicker, the disc valve assembly 1
3 is spaced apart from the protrusion 14A of the retainer 14, a variable throttle multi-passage is formed, the flow area between the oil chambers A and B is increased, and the rate of change in damping force characteristics is alleviated. As a result, the damping force characteristics change in two stages.

On the other hand, histone 6 and piston rod 5 are connected to cylinder 1.
When the oil enters the oil chamber, the pressure in the oil chamber B increases and the pressure in the oil chamber A decreases. For this purpose, the pressure in the oil chamber B acts on the disc valve assembly 13 through the passage 9, causing the disc valve assembly 13 and the retainer 14 to
7 in a direction away from the piston 6.

8 spaces are made to communicate. However, the pressure inside the oil chamber B is high due to the volume of the piston rod 5 entering the inner cylinder IA, and a pressure difference is generated between the oil chamber B and the oil chamber C.

Due to this differential pressure, oil flows from the oil chamber B to the oil chamber C via the reduction-side damping force generation mechanism 12, causing the piston 6 to displace at a low speed, and this differential pressure is applied to the disc valve assembly 21.
When the spring force is less than the spring force, a damping force having a constant characteristic is generated by the fixed throttle passage formed by the notched groove 27.

Furthermore, when the piston 6 is displaced at high speed and the differential pressure becomes larger than the spring force of the disc valve assembly 21, the inner circumferential edge of the disc valve assembly 21 separates from the protrusion 22A of the retainer 22, so that the variable throttle 9 can be properly adjusted. When this occurs, the damping force characteristics for the piston 6 change.

The damping force characteristics with respect to the speed of the piston 6 are as shown in FIG.

By the way, from the viewpoint of the riding comfort of the vehicle, it is better not to make the damping force of the hydraulic shock absorber too large.

On the other hand, if the damping force is reduced, the steering stability of the vehicle may be impaired. Therefore, when the displacement speed of the piston 6 is in a low speed range, the damping force is set to be small considering riding comfort, and when the displacement speed of the piston 6 is in a high speed range, where steering stability becomes a problem, the damping force is set to be large. The hydraulic pressure M that can set the damping force with the characteristic: The shock absorber is optimal. However, in the conventional hydraulic shock absorber described above, since the orifice area of the notched groove 18°2-7 is constant, the damping force characteristics during the fourth gear displacement of the piston 6 are constant, and the damping The degree of freedom in force setting is small. For this reason, there is a drawback that either the riding comfort or the handling stability of the vehicle must be sacrificed to some extent.

The present invention has been made in order to eliminate the drawbacks of the prior art described above, and the damping force characteristics are changed in three stages, thereby increasing the degree of freedom in setting the damping force in the low piston displacement speed range. Its purpose is to provide a buffer.

In order to achieve the above-mentioned object, the configuration adopted by the present invention includes a piston or a cylinder consisting of a piston and a df) dam member, a realm defining member that defines a plurality of oil chambers in the cylinder,
A passage provided in the immortal realm-defining member and communicating oil chambers on both sides defined by the immortal realm-defining member, and a retainer provided facing the immortal realm-defining member and the immortal realm-defining member. a disc valve assembly for opening and closing the passage, and a first disc valve assembly of the disc/globe assembly that abuts against the sacred realm defining member or retainer;
an orifice provided in the disk of the invention that communicates the two front chambers, and an orifice formed between the first disk and a disk of the bacteria 2 adjacent to the first disk, the two disks being close to each other and separated from each other; In particular, it is characterized by being formed of a spacer that increases or decreases the opening area of the orifice, and a fixed orifice that is formed in any one of the sacrum defining member, the piston rod, and the retainer and that constantly communicates the two anterior chambers. It is something to do.

In this way, when the displacement speed of the piston is in a low speed range, the fixed orifice formed in either the fairy-defining member, the piston rod, or the tom member and the orifice formed in the disk described in 1. The flow path surface is fine, and the fixed orifice is a fixed orifice with nine fixed passages whose flow area is always constant regardless of changes in the differential pressure between the two front chambers, and the orifice responds to the increase in the differential pressure between the two front chambers. First. By bringing the second disk close to each other, nine variable throttle passages are formed in which the surface roughness of the flow path is reduced. A predetermined damping force on the piston is obtained by the flow resistance of the oil passing through the fixed throttle passage and the variable throttle passage.

Next, when the displacement speed of the piston increases, the variable throttle 9 passage described above is closed, and the flow area between the two front chambers becomes only the fixed throttle passage, so that the damping force changes.

Furthermore, when the piston increases in speed, the disc pulp assembly is wrapped around it, opening the passage provided in the realm-defining member and forming a new variable throttle passage, which further changes the damping force. Therefore, the damping force applied to the piston changes in three stages.

As a result, the degree of freedom in setting the damping force in the low-speed piston displacement range increases, and by appropriately designing the opening area of the orifice formed in the first disk and the thickness of the spacer, it is possible to It is possible to achieve a damping force characteristic that has a small damping force, a large damping force in the medium speed range, and a slow change in the high speed range, and a damping force characteristic that is close to the ideal. This has the effect of making it possible to

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

First, FIGS. 5 to 18 show a first embodiment of the present invention, and the same components as in FIGS. 1 to 3 are given the same reference numerals and their explanations will be omitted. shall be taken as a thing. Thus, the extension side damping force generation mechanism 31 is the fifth
The configuration is as shown in the figure. First, the piston rod 5 has a concave portion 5D with a bottom from its distal end to its proximal end.
is formed, and an orifice passage 32 is bored, and one end of the orifice passage 32 is connected to the oil chamber A.
], and the other end is open to the four parts 5D.

Therefore, a fixed throttle passage is formed in which the oil chambers A and B are constantly communicated via the orifice passage 32 and the recess 5D.

Next, between the piston 6, which forms the space between the oil chambers A and B and serves as the seminal realm-defining member, and the taker 14, which is placed inside the oil chamber A and faces the piston 6, 1st from the piston 6 side. Second. Third and fourth disks 33A, 3
A disc valve assembly 33 consisting of 3B, 33C, and 33D is interposed.

However, the first . The second disks 33A, 33B are not in close contact with each other, and a spacer 34 is interposed between them.
It is held at a distance t from the outer peripheral edge of B. In addition, one or more orifices 35 are bored in the side surface of the disk 33A of Ml, as shown in FIG. A flow path between chambers A and B is formed, and a flow path between chambers A and B is formed. Second disk 33A, 33
There are nine variable throttle passages whose multi-channel area changes depending on the proximity and separation of B.

Furthermore, when the outer circumferential edge of the disk pulp assembly 33 is held between the protrusion 6A of the piston 6 and the protrusion 14B of the retainer 14, and the inner circumference thereof is bent and separated from the fourth disk 33D, the above-mentioned A variable throttle passage similar to that described in the prior art is formed between the fourth disk 33D and the protrusion 14A of the taker 14.

As shown in FIG. 7, the spacer 34 is formed of an annular plate whose outer circumferential edge has a smaller diameter than the formation area of the orifice 35 of the first disk 33A, and whose inner circumferential edge is in contact with the guide member 15. ing. The inner peripheral edge of the spacer 34 has a plurality of notch grooves 34A, 34A extending toward the outer peripheral side.
. . . are formed so that the inner peripheral portion of the disc pulp assembly 33 does not become an obstacle to the variable throttle passage formed when the inner peripheral portion of the disc pulp assembly 33 is separated from the protrusion 14A of the taker 14.

Next, the reduction side damping force generation mechanism 36 has a configuration shown in FIG. 8. That is, the retainer 22 has an orifice passage 37 formed at its center that forms a fixed throttle passage, and the space between the oil chambers B and C serves as the orifice passage 37 and other celestial-defining members. Passage 11 provided in member 7
We are in constant communication. Furthermore, there is a gap between 2 and 1 between the detom member 7 and the retainer 22. second and third disk 3
8A.

A disk pulp assembly 38 consisting of 38B and 38C is interposed. And the disc pulp assembly 38
1st. Second disk 38A.

A spacer 39 is also interposed between 38B, and the spacer 39
is the same as the spacer 34 described above. second disk 38
A and 38B are kept separated by a distance Mt. Also, the first disk 38AK is provided with one or more orifices 4o, similar to the first disk 33A of the disk pulp assembly 33. Second
The gap between the disks 38A, 38B and the orifice 4
The oil chambers B and C communicate with each other through the ship 1. The second disks 38A and 38B have nine variable throttle passages with a 5'J change in flow path depending on the proximity and separation of the second disks 38A and 38B. Furthermore, the protrusion 22A of the retainer 22 and the disc pulp assembly 3
When the inner peripheral portion of the disk pulp assembly 38 is bent, a variable squeezing passage similar to that shown in the prior art is formed between the disk pulp assembly 38 and the third disk 38C of the disk pulp assembly 38.

The spacer 39 of the reduction side damping force generation mode 4/h36 is also formed of an annular plate, and its outer peripheral edge is connected to the first disk 38A.
The spacer 39 has a smaller diameter than the oriice formation site, the inner circumferential edge coincides with the inner circumferential edge of the first disk 38A, and the spacer 39 is fixed to the first disk 38A or the second disk 38B so as not to be displaced in the radial direction. It is provided.

The aforementioned orifices 35, 40 can also be formed with the straight notched grooves 35', 4Q' shown in FIG.

Further, as shown in FIG. 10, the spacers 34, 39 include a protrusion 41 projecting in an annular shape toward the first disks 33A', 38A' and the second disks 33B, 38B 111jl; As shown in Figure 11, the second
It can also be formed by annular projections 42 formed on the disks 33B' and 38B'. Furthermore, as shown in FIGS. 12 and 13, the first disks 33A'', 38A''? It can also be formed by a stepped portion 43 formed by bending the outer peripheral edge in a direction away from the second disks 33B, 38B.

The hydraulic shock absorber according to the present invention has the above-mentioned configuration,
Next, the operation will be explained based on FIGS. 14 to 17. First, the piston 6 and the piston rod 5
When is displaced in the extension direction, a pressure difference occurs between oil chambers A and B,
Oil fluid flows from oil chamber A toward oil pressure B. When the displacement speed of the piston 6 is in a low speed range, the flow path between the oil chambers A and B is formed by a fixed throttle passage consisting of an orifice passage 32 and a spacer 34, as shown in FIG. and the orifice 35 provided in the first disk 33A.
It is formed with a variable diaphragm and multiple passages. Moreover, when the displacement speed of the piston 6 increases, the first disk 33A
is bent toward the second disk 33B, and the flow path area of the variable throttle multi-passage is reduced. In this case, the damping force characteristics of the first stage are exhibited.

Next, as shown in Figure 14, the first f''isk 33
When A comes into contact with the second disk 33B, the variable throttle passage is closed, and only the fixed throttle passage consisting of the OriSwiss passage 32 becomes a flow path between the oil chambers A and B, and the damping force characteristics for the piston 6 change. do.

Then, the disk pulp assembly 33 is bent and the first
As shown in FIG.
The flow path area does not change until it is sandwiched between 4B and 4B.

Furthermore, when the displacement speed of the piston 6 becomes high, the inner peripheral edge of the disc pulp assembly 33 is bent as shown in FIG. A throttle passage is formed. Due to this, the damping force characteristics further change, and as a result, the piston 6
The damping force characteristics change in three stages depending on the displacement speed of the damping force.

On the other hand, when the piston 6 and the piston rod 5 are displaced in the contraction direction, the contraction side damping force generation mechanism 36 is activated due to the flow resistance of the oil flowing from the heel oil chamber B to the oil chamber C. A damping force characteristic that changes in stages can be obtained. At this time, between the oil chambers A and B, the disc pulp assembly 33 and the retainer 1 are connected as shown in FIG.
4 is displaced against a spring 17.

FIG. 18 shows the damping force characteristics on the expansion side and contraction side described above. As is clear from a comparison between this and the damping force characteristics of the hydraulic shock absorber according to the prior art shown in FIG. By appropriately selecting the thickness of the spacer 34, 39, the opening area of the orifice 35, 40, etc., the damping force in the low speed range can be set small.

Next, FIGS. 19 and 20 show a twenty-first third embodiment of the present invention. Shown in different locations. In the embodiment shown in FIG. 19, the piston 6 is provided with an orifice passage 51 forming a fixed orifice. The orifice passage 51 opens into the oil chamber A on one side and into the passage 9 on the other side. On the other hand, in the embodiment shown in FIG. 20, a fixed orifice is formed by cutting a groove 61 (r) in the radial direction of the protrusion 6A of the piston 6.
Ru. And Kokura orifice passage 51, notch 1#6
1, the oil chambers A and B are always kept in communication regardless of the differential pressure therebetween. In addition, Fig. 19, 2
Although the extension-side damping force generation mechanism 31 has been described in the embodiment shown in FIG. 0, an orifice passage or notch groove similar to that described above may be provided in the circumferential trunk portion or the protrusion 7A of the detom member 7. These orifice passages and cutout grooves can be provided at one or more locations.

Components and operations other than those described above are the same as those in the first embodiment, so the same components are given the same reference numerals and their explanations will be omitted.

Furthermore, FIG. 21 shows a fourth embodiment of the present invention, in which a disk pulp assembly 71 is constructed and an orifice 72 is provided.
IAI'i is arranged on the retainer 14 side, and the second. Third and fourth disks 71B, 71C
, 71D are provided. And the first. Second disk 71A.

The spacer 73 interposed between the disks 71B is located on the outer peripheral side of the orifice 72 of the first disk 71A. Components other than those described above are the same as those in the first embodiment, so the same components are given the same reference numerals and their explanations will be omitted.

Further, in this embodiment, the variable throttle passage passing through the orifice 72 is connected to the orifice 72. 1st. second disk 7
1A, 71B and the gap between the inner peripheral edge of the disc valve assembly 71 and the guide member 15, and the protrusion 1 of the beam retainer 14 that makes the flow path variable.
4A is performed by suppressing and displacing the inner peripheral edge of the first disk 71A toward the second disk 71B.

In each of the above embodiments, the extension side damping force generation mechanism 31 is provided facing the piston 6, and the contraction side damping force generation mechanism 36 is provided on the tom member 7 side. 31 and 36 may be provided facing both sides of the piston 6. Also, not necessarily the extension side,
It is not necessary to provide a damping force generating mechanism having a three-stage characteristic on both the reduction side, and for example, the damping force generation mechanism may have a two-stage characteristic on the reduction side as in the prior art. Furthermore, a single-handed hydraulic shock absorber may be provided in which only one damping force generation mechanism is provided on either the extension side or the contraction side. Furthermore, although the disc valve assemblies 33 and 38 are constructed with four discs and three discs, respectively, the number of discs is not limited to the above-mentioned numbers as long as it is plural. Furthermore, although the cylinder 1 is of a double cylinder type consisting of an inner cylinder IA and an outer cylinder IB, it may be of a single cylinder type.

[Brief explanation of drawings]

Figures 1 to 4 show the prior art, in which Figure 1 is a longitudinal sectional view of a hydraulic shock absorber, and Figures 2 and 3 are Figure 1 showing the damping force generation mechanism on the extension side and contraction side, respectively. FIG. 4 is a damping force characteristic diagram, FIGS. 5 to 18 show the first embodiment of the present invention, FIG. 5 is a sectional view similar to FIG. 6 is an external view of the first disk, FIG. 7 is an external view of the retainer, FIG. 8 is a sectional view similar to FIG. 3, and FIG. 9 is an external view showing a modification of the first disk. FIG. 10 is a half-sectional view showing a first modified example of the disc valve assembly, FIG. 11 is a half-sectional view showing a second modified example of the disc valve assembly, and FIGS. 12 and 13 are each a disc valve assembly. 14 to 17 are sectional views similar to FIG. 5 showing different operating states, FIG. 18 is a damping force characteristic diagram, 19 to 21 respectively show the second embodiment of the present invention. Third. FIG. 6 is a sectional view similar to FIG. 5 showing a fourth embodiment. 1...Cylinder, 5...Piston rod, 6...
Piston, 7... bottom member, 9, 11... passage,
14゜22... Retainer, 31... Extension side damping force generation mechanism, 32. 37, 51... Orifice passage, 33
, 38°71...Disc valve assembly, 33A, 3
3B. 33C, 33D, 38A, 38Bt38C, 71A. 71B, 71C, 710 --- Disk, 34, 39
...Spacer, 35 * 35' t 40 t 4
0'... Orifice, 36... Reduction side damping force generation mechanism, 61... Notch groove. Patent Applicant Tokico Co., Ltd. Figure 2 Figure 5 Figure 6 Figure 7 Figure 5 Figure 8 Figure 9 Figure 14 Figure 15 Figure 16 Figure 17 Figure 19 Figure 20

Claims (9)

[Claims] (1) A cylinder filled with oil and gas, a piston rod with one end located inside the cylinder and the other end protruding outside the cylinder, and a piston rod that is inserted into the piston rod and runs inside the cylinder. In a hydraulic shock absorber having a piston that is slidably displaced and generating a damping force in response to displacement of the piston, the inside of the cylinder is defined by a plurality of oil chambers made of the piston or the piston and a bottom member. a passageway provided in the immortal realm defining member that communicates oil chambers on both sides defined by the nuclear immortal realm defining member; A disk pulp assembly comprising a plurality of disks interposed between the retainer and the retainer, which opens and closes the front i-pi passage; an orifice provided in the abutting first disk and communicating the two front chambers; formed between the first disk and a second disk adjacent to the first disk;
a spacer that increases or decreases the opening area of the orifice when the two disks approach or separate; and a fixed orifice that is formed on any one of the sacrum defining member, the piston rod, and the retainer and that constantly communicates the two anterior chambers. A hydraulic shock absorber characterized by being formed from. (2) Above 1. The hydraulic shock absorber according to claim (1), characterized in that a spacer member is interposed between the second disks. (3) The hydraulic shock absorber according to claim 0, characterized in that the first disk is provided with a spacer portion that projects toward the second disk. (4) The hydraulic shock absorber according to claim (1), wherein the second disk is provided with a spacer portion that projects toward the first disk. (5) The hydraulic shock absorber according to claim 0, wherein the fixed orifice is formed by an orifice passage bored in the NfJ piston rod. (6) The hydraulic shock absorber according to claim (1), wherein the fixed orifice is formed by an orifice passage bored in the piston. (7) The hydraulic shock absorber according to claim 0, wherein the fixed orifice is formed by a notched groove provided on the contact surface of the piston with the disc pulp assembly. (8) The hydraulic shock absorber according to claim (1), wherein the fixed orifice is formed by an orifice passage bored in the retainer. (9) The hydraulic shock absorber according to claim (1), wherein the two leg orifices are formed by orifice passages bored in the bottom member. αQ The hydraulic shock absorber according to claim (1), wherein the fixed orifice is formed by a notched groove provided in a contact surface of the tom member with the disc pulp assembly.