JPH0694065A - Damping force adjusting device for hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A large difference between the high damping force and the low damping force is obtained to improve the riding comfort of the vehicle and to make the damping force variable. (EN) Provided is a damping force adjusting device for a hydraulic shock absorber capable of achieving various characteristics and independently setting hard and soft damping force characteristics. [Structure] Inside the valve housing below the piston rod 3, there is a passage 4 that connects the first extension port 2b to the lower oil chamber.
An expansion-side damping valve 10 for providing a variable damping force depending on the vibration frequency is provided in the middle of this passage so as to be openable and closable, and a first pressure-side leaf is provided at the upper end of the first pressure port 2a. A valve 5 is provided so as to be openable and closable, and a piston rod 3 is provided with a bypass communicating with an upper oil chamber. This bypass is communicated with a lower oil chamber through a port formed in a valve housing. A valve was provided to adjust the opening area of the bypass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjusting device for a hydraulic shock absorber in a two-wheeled vehicle, a four-wheeled vehicle or the like which is interposed between a vehicle body and an axle of a vehicle to absorb and reduce impact energy from a road surface.

[0002]

2. Description of the Related Art As hydraulic shock absorbers of this type, for example, Japanese Utility Model Laid-Open No. 63-59237 and Japanese Unexamined Patent Publication No. 142941/1990.
The one disclosed in the publication is being developed.

In the hydraulic shock absorber disclosed in Japanese Utility Model Laid-Open No. 63-59237, a large change in damping force can be obtained from a low speed region to a high speed region of the piston speed, and there is a large difference between the high damping force and the low damping force. As a result, the riding comfort of the automobile is improved in a situation where a high piston speed is generated on a rough road surface or a bad road.

The hydraulic shock absorber disclosed in Japanese Patent Application Laid-Open No. 2-142941 improves the riding comfort by changing the damping force depending on the vibration frequency.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The hydraulic shock absorber of Japanese Patent No. 23 has the above effect, but since it does not include a valve that generates a damping force depending on the frequency, when the damping force is variable according to the input frequency,
Since it is necessary to rotate the rotary valve from outside each time via an actuator to switch the damping force, the operability and responsiveness are inferior.Furthermore, not only the actuator but also the rotary valve is frequently used and durability is a problem. Next to
Further, there is a problem that durability of a control rod and a seal for holding this is required.

On the other hand, the hydraulic shock absorber disclosed in Japanese Unexamined Patent Publication No. 2-142941 obtains a low damping force at the time of high frequency input due to the hat-cut characteristic, but at the secondary resonance point, the damping force remains low, so that the unsprung flare is suppressed. However, there is a problem in that the riding comfort in the soft damping force region cannot be improved because a large difference between the high damping force and the low damping force cannot be obtained.

Therefore, an object of the present invention is to obtain a large difference in damping force from the low speed region to the high speed region of the piston speed, and also to obtain a large difference between the high damping force and the low damping force to improve the riding comfort of the vehicle. In addition, the damping force can be varied depending on the vibration frequency, the characteristics of low damping force can be made relatively linear, and the damping force characteristics of the hydraulic shock absorber can be set independently for hard and soft damping forces. It is to provide a device.

[0008]

In order to achieve the above object, the structure of the present invention is such that a piston rod is movably inserted into a cylinder via a piston, and the piston has two upper and lower oil chambers in the cylinder. A first extension port and a first pressure port that communicate with the two oil chambers are formed in the partition, and a valve housing is provided at a lower portion of the piston rod, and the first housing is provided in the valve housing. A passage that connects the extension port to the lower oil chamber is provided, and an extension-side damping valve that varies the damping force depending on the vibration frequency is provided in the middle of this passage so that it can be opened and closed. Is provided with a first pressure side leaf valve that can be opened and closed, and a piston rod is provided with a bypass communicating with the upper oil chamber. This bypass communicates with the lower oil chamber via a port formed in the valve housing, The in the piston rod is characterized in the provision of the valve for adjusting the opening area of the bypass.

[0009]

[Function] When the bypass is closed, the expansion side damping valve provides a hard expansion side damping force, and on the compression side, the first compression side leaf valve generates a hard compression side damping force, and when the bypass is open. Generates a synthetic medium and a soft damping force on the extension side and the compression side according to the opening area.

Further, the expansion side damping valve generates a damping force depending on the frequency.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention.

As shown in FIG. 1, a hydraulic shock absorber according to an embodiment of the present invention includes a cylinder 1 having a closed cylindrical body, a piston 2 slidably inserted in the cylinder 1, and a piston 2 to a cylinder. 1 and a piston rod 3 which extends through the upper end sealed portion and extends outward.

The piston 2 is fitted in the lower spigot portion 3e of the piston rod 3, and a gasket 18 made of a sealing member such as metal rubber is applied to the lower surface of the piston 2, and the gasket 18 serves to connect the piston 2 and the piston rod 3. The joint surfaces of the lower spigot portion 3e and the piston nut 4 serving as a valve housing are sealed and fixed to the piston rod 3 with a piston nut 4 screwed from below into the lower end spiral portion 3a of the piston rod 3.

The piston 2 divides the inside of the cylinder 1 into an operating oil chamber A which is an upper oil chamber on the rod side and an operating oil chamber B which is a lower oil chamber on the head side, and at the time of extension of the hydraulic shock absorber. By flowing the hydraulic oil in the upper hydraulic oil chamber A from the piston 2 to the lower hydraulic oil chamber B through the extension side damping force generating mechanism, the extension side damping force generating mechanism part generates a damping force during the extension stroke. .

Further, during the compression stroke, the hydraulic oil in the lower hydraulic oil chamber B is made to flow from the piston 2 and the base valve 40 to the upper hydraulic oil chamber A and the reservoir chamber through the respective pressure side damping force generating mechanisms, so that these pressure side The damping force generation mechanism generates the damping force during the compression stroke.

To this end, the piston 2 has two sets of a first pressure side port 2a on the outer peripheral side and a first expansion side port 2b on the inner peripheral side which communicate the upper hydraulic oil chamber A and the lower hydraulic oil chamber B. A port group of is provided.

The lower end of the pressure side port 2a group is directly opened to the lower hydraulic oil chamber B, and the upper end thereof is connected to the upper hydraulic oil chamber A through the rear valve 5 which is a first pressure side leaf valve which is a pressure side damping force generating mechanism. I understand.

The extension side port 2b group communicates with the extension side damping force generating mechanism side through a passage 4b formed in the piston nut 4, and the upper end passes from an annular groove 2e formed on the upper surface of the piston 2 through the passage 2f. It communicates with the upper hydraulic oil chamber A.

The extension side damping force generating mechanism generates a damping force depending on the frequency. The damping force is generated by the annular rib 8e of the supporting member 8 which is caulked to the lower end of the piston nut 4 and the supporting member 8. The leaf valve 10 is a first expansion-side damping valve whose outer circumference is fixed by an annular rib 9e of the valve seat 9 which is disposed so as to face the upper surface and which is sandwiched by the outer circumference.

As will be described later in detail, the control mechanism includes a push member 11 which is vertically movably fitted into the inner peripheral surface of the valve seat 9 and a pin 12 on the push member 11.
Leaf springs 13, which are caulked by the block springs, block members 14 arranged above them, and block members 1.
4 and a perforated plate 60 arranged on the upper surface of the base plate 4.

The perforated plate 60 has a central control orifice 61.
And an outer hole 62.

The valve seat 9 of the extension side damping force generating mechanism is
A plurality of through holes 9b arranged side by side on a concentric circle, and an annular groove 9d formed on the lower surface in communication with these through holes 9b,
Push member 11, leaf spring 13 on the control mechanism side
Also, together with the block member 14, the upper end of the cap-shaped member 16 having the opening 16b is hooked on the block member 14, and the lower end of the cap-shaped member 16 is press-fitted into the valve seat 9 to be preassembled as a sub-assembly. .

A leaf spring 63 is interposed between the sub-assembled cap member 16 and the inner step of the hollow piston nut 4, and a hole 64 is formed in the center of the leaf spring 63.
Are formed. As a result, the entire sub-assembled parts are always pressed downward while sealing oil-tightly.

Thus, the leaf valve 10 includes the leaf spring 6
The outer peripheral portion is sandwiched between the annular ribs 8e of the support member 8 and the annular rib 9e of the valve seat 9 from above and below by the restoring force of 3, and the inner peripheral upper surface of the leaf valve 10 is the seat on the inner peripheral lower surface of the valve seat 9. The annular groove 9d that is normally formed between the annular rib 9e of the valve seat 9 and the seal portion 9f is closed by pressing against the portion 9f, and the upper hydraulic oil chamber A moves from the passage 2f on the upper surface of the piston 2 to the extension side port. 2b-passage 4b of piston nut 4-opening 16b of cap-shaped member 16
-And valve seat 9b-The leaf valve 10 also prevents the lower hydraulic oil chamber B from communicating with the annular groove 5d.

The leaf valve 10 is clamped by utilizing the restoring force of the leaf spring 63 because the leaf valve 10 is clamped by the dimension error of the support member 8, the valve seat 9, the cap-shaped member 16 and the like. This is to prevent backlash.

The extension side control mechanism for controlling the extension side damping force generating mechanism is composed of a push member 11 fitted on the inner peripheral surface of the valve seat 9 so as to be vertically movable, and a pin 12 caulked in the hollow of the push member 11. It has a stopped leaf spring 13.

The leaf spring 13 is clamped at its outer peripheral portion between the valve seat 9 and the block member 14 at the time of the above subassembly, and the spring force of the leaf spring 13 normally keeps the push member 11 in the upper position.

Further, in this state, the lower surface sheet portion 11e of the push member 11 formed to have the same thickness as the valve seat 9 closely faces the inner peripheral side upper surface of the leaf valve 10 or is in a state of being in contact therewith. It is in.

A first-order lag pressure chamber R for adjusting the extension side damping force is formed between the leaf spring 13 connected to the push member 11 with the pin 12 and the lower surface of the block member 14, and this first-order lag pressure chamber R is formed. R communicates with the hollow portion of the piston nut 4 and the passage 4b through the through hole 14c of the block member 14 and the control orifice 61.

The through hole 9b of the valve seat 9 is opened on the upper surface of the leaf valve 10, and the through hole 9b is formed in the cap-shaped member 1.
The inner passage 65 and the passage 62 communicate with the passage 4b.

In short, a passage communicating with the first extension port 2b is formed in the piston nut 4, and a frequency-dependent first extension side damping valve is provided in the middle of this passage.

A disc 23 and valve retainers 7 and 27 are provided on the outer periphery of the piston rod 3 above the piston 2. The disc 23 interposed between the valve retainers 7 and 27 has a second branch that opens into the upper hydraulic oil chamber A.
The extension port 66 and the second pressure port 67 of the
A second expansion side leaf valve 68 is openably and closably provided at an upper opening end of the expansion port 66 of the second expansion port 66, and a second compression side leaf valve 69 is openably and closably provided at a lower opening end of the second pressure port 67. ing.

A passage 70, which is a common bypass in the vertical direction, is formed in the piston rod 3.
A port 71 opening to the upper hydraulic oil chamber A is formed in the.

A common passage 76 communicating with the second extension port 66 and the pressure port 67 is formed in the disc 23, and the passage 76 is formed in the ports 72, 73 formed in the piston rod 3.
Is connected to the passage 70 via.

A port 75 penetrating in the lateral direction and opening to the lower hydraulic oil chamber B is formed in the upper part of the piston nut 4.
The port 75 communicates with the passage 70 via a port 74 formed in the piston rod 3.

As a result, the second expansion side port 66 and the compression side port 67 are communicated with the lower hydraulic oil chamber B through the ports 72 and 73, the first bypass, the passage 70, and the ports 74 and 75.

Similarly, the upper hydraulic oil chamber A communicates with the lower hydraulic oil chamber B via the port 71, the passage 70, and the ports 74 and 75 which are the second bypass.

A rotary valve 15, which is a valve, is rotatably inserted into the central passage 70 of the piston rod 3, and the rotary valve 15 has upper spacers 21a and 21b.
And is supported by lower hollow collars 22a and 22b.

The rotary valve 15 is connected to a control rod 20, and the control rod 20 is inserted into the piston rod 3 while being rotatably inserted therein, and protrudes to the outside, and is rotatably operated by an actuator or manually from the outside.

The rotary valve 15 is provided with one or a plurality of variable orifices 77 facing the second bypass port 71, and variable ports 78, 79 facing the first bypass ports 72, 73. Valve 1
By rotating 5, the variable orifice 77 and the variable ports 78 and 79 are controlled to the fully closed, half-opened, and fully-opened states to generate seed, medium, and soft damping forces, respectively.

The valve may be a valve that moves up and down instead of the rotary valve, and the point is that it can adjust the opening areas of the first and second bypasses.

A base valve 40 for opening and closing the lower hydraulic oil chamber B to the reservoir is provided below the cylinder 1.

A frequency dependent pressure side damping force generation mechanism similar to the extension side damping force generation mechanism is also provided for the base valve 40 which is the pressure side damping force generation mechanism disposed at the lower end of the cylinder 1.

That is, the base valve 40, which is a compression side damping force generating mechanism, has a support member 41 fitted to the lower end of the cylinder 1.
Has an outer peripheral fixed leaf valve 43 whose upper and lower outer peripheral surfaces are sandwiched by an annular rib 41e of the above and an annular rib 42e of a valve seat 42 arranged so as to face the upper surface of the support member 41. A compression damping force is generated at the valve 40.

Leaf valve 4 for generating the compression side damping force
In order to give the frequency-dependent characteristic to 3, the base valve 40 further includes a push member 44 that is vertically movably housed on the inner peripheral surface of the valve seat 42.
Further, a leaf spring 46 which is caulked by a pin 45, a disc 47 which is arranged above the leaf spring 46, and an orifice plate 48 which is provided on the disc 47 are provided.

The valve seat 42 is provided with a plurality of through holes 42b arranged in a concentric circle and bored, and an annular groove 42d formed on the lower surface so as to communicate with the through holes 42b, and the push member 44, the leaf spring 46, and Together with the disc 47, the upper end of the cap member 49 having the opening 49b is hooked on the disc 47, and the lower end of the cap member 49 is press-fitted into the valve seat 42 to be preassembled as a sub-assembly.

The leaf spring 46 and the disc 4
7, there is a first-order lag pressure chamber R1. This first-order lag pressure chamber R1 communicates with a lower working oil chamber B in the cylinder 1 from a hole 47c formed in the disk 47 through an orifice hole 48c of an orifice plate 48. There is.

Then, the sub-assembled members are vertically movably housed in a case member 50 having an opening 50b in which a lower end thereof is press-fitted and attached to a support member 41, and a space between the disk 47 and the case member 50. The base valve 40 is configured by pressing the annular rib 42e of the valve seat 42, which is sub-assembled with the spring 51 interposed therebetween, against the leaf valve 43.

The leaf valve 10 which is the expansion side damping force valve and the leaf valve 43 which is the compression side damping valve have substantially the same structure and have the same operation and effect.

At the time of extension, the oil in the upper hydraulic oil chamber A passes through the passage 4b.
And flows out into the piston nut 4 and bends the leaf valve 10 to flow out into the lower hydraulic oil chamber B. At this time, the oil corresponding to the discharge volume of the piston rod 3 lifts the leaf valve 43 in the base valve 40 and lowers. The hydraulic oil chamber B is supplied from the reservoir.

At the time of compression, the oil in the lower hydraulic oil chamber B deflects the leaf valve 43 of the base valve 40 and flows out to the reservoir, and a part of the oil flows from the pressure port 2a of the piston 2 to the rear valve 5 which is the first pressure side leaf valve. Through the upper hydraulic oil chamber A
Spill to.

More specifically, during the extension stroke in which the piston 2 moves toward the upper hydraulic oil chamber A side,
The hydraulic fluid in the upper hydraulic fluid chamber A passes through the first extension port 2b of the piston 2, the passage 4b of the piston nut 4, the opening member 16b of the cap-shaped member 16, the through hole 9b of the valve seat 9, and the leaf valve 10. While the inner circumferential side of B is flown downward to generate the expansion side damping force and flows into the lower hydraulic oil chamber B, the hydraulic pressure generated in the upper hydraulic oil chamber A, which is the expansion side damping force itself, is blocked by the orifice 61. Through hole 14 of member 14
It is guided to the primary delay pressure chamber R through c, and this hydraulic pressure acts to push the push member 11 downward against the leaf spring 13.

Therefore, if the vibration frequency during the extension stroke is equal to or lower than the vibration frequency set by the orifice 61 at that time, the hydraulic pressure generated in the upper hydraulic oil chamber A (as described above:
The expansion side damping force) acts on the first-order lag pressure chamber R through the orifice 61 to push down the push member 11 to bend the inner peripheral end side of the leaf valve 10 downward,
When the vibration frequency in the extension stroke exceeds the vibration frequency set by the orifice 61, the hydraulic pressure generated in the upper hydraulic oil chamber A passes through the orifice 61 and the primary lag pressure chamber R is generated. The piston 2 moves to the compression stroke before being transmitted to the valve, and the so-called orifice 61 performs a first-order lag action. Therefore, the hydraulic pressure in the first-order lag pressure chamber R does not rise and is kept at a low value, and the push member 11 leaves the leaf. The spring force of the spring 13 does not bend the inner peripheral end side of the leaf valve 10 downward while keeping the raised position, so that the generated damping force becomes lower than a predetermined value.
It acts as a frequency-dependent hydraulic shock absorber with a high-cut effect.

Similarly, in the base valve 40, the orifice 4
8c performs high cut action during compression operation.

Next, the overall operation will be described.

Variable orifice 77 and variable ports 78, 7
When 9 is fully closed, the leaf valve 10 produces a hard damping force. That is, the variable orifice 77 and the variable port 7
Since 8, 79 are closed, the oil in the upper working oil chamber A passes through the first extension port 2b into the piston nut 4 and extends from the leaf valve 10 at the time of extension while having the high cut characteristic as described above. The oil corresponding to the discharged volume of the piston rod 3 flows out to B and is replenished to the lower hydraulic oil chamber B from the reservoir through the base valve 40.

The extension side damping force characteristic at this time is shown by the graph F in FIG.
It is indicated by r1.

During the compression operation, the oil in the lower hydraulic oil chamber B flows out from the leaf valve 43 of the base valve 40 to the reservoir, and a part of the oil flows from the first pressure port 2a through the rear valve 5 into the upper hydraulic oil chamber A. Spill to.

At this time, the leaf valve 43 has a high cut characteristic and has a hard damping force, and this characteristic is shown by the graph Fc1 in FIG.

Next, the rotary valve 15 is rotated to fully open the variable orifice 71 and the variable ports 78 and 79 so that the oil also flows from the first and second bypasses, so that a soft damping force can be obtained.

At this time, the leaf valve 10 and the rear valve 5
The cracking pressure is set high, and the cracking pressures of the second expansion side leaf valve 68 and the second compression side leaf valve 69 are set low.

Therefore, during expansion and compression, the second expansion side leaf valve 68 and the second compression side leaf valve 69 are opened first.

At the time of extension, in the low speed region, the oil in the upper hydraulic oil chamber A flows from the second bypass 77 to the passage 70-ports 74, 7.
5 through the lower hydraulic oil chamber B, the variable orifice 7
A resistance of 7 generates a damping force on the extension side.

When the piston speed increases, the flow rate increases, and the differential pressure generated in the variable orifice 77 exceeds the cracking pressure of the second expansion side leaf valve 68, the second expansion port 66-passage 76 serving as a second bypass. -Ports 78 and 79-Flows to the lower hydraulic oil chamber B through the passages 74 and 75, and the damping force has the characteristic of the variable orifice and the characteristic of the combination of the second expansion side leaf valve 68.

The flow rate is further increased and the differential pressure is increased by the leaf valve 1.
When the cracking pressure of 0 is exceeded or the input frequency is increased, the leaf valve 10 is also fed from the first extension port 2b.
And flows into the lower hydraulic oil chamber B via the, and has a high cut characteristic according to the input frequency as in the case of the above hardware.

The damping force at this time is the variable orifice 77,
This is a combined characteristic of the second expansion side leaf valve 68 and the first expansion side leaf valve 10.

That is, in the low speed range, the damping force is determined by the variable orifice 77 and the second expansion side leaf valve 68, and in the high speed range, the damping force is determined by the combination with the first expansion side leaf valve 10. This characteristic is shown in FIG. 2 is represented by the graph Fr2.

During the compression operation, the cracking pressure of the second pressure side leaf valve 69 is set low, so that the oil in the lower hydraulic chamber B in the low speed region is in the ports 74, 75-passage 70.
-Flows through the variable orifice 77 to the upper washer oil chamber A,
The resistance of the variable orifice 77 at that time and the base valve 40
A damping force is generated due to the characteristics of.

When the piston speed increases, the flow rate increases, and the differential pressure generated at the variable orifice 77 exceeds the cracking pressure of the second expansion side leaf valve 68 and the second compression side leaf valve 69, the variable orifices 78 and 79 are generated. A flow through each leaf valve 68, 69 also occurs.

The damping force at this time is the variable orifice 77,
This is a combined characteristic of the leaf valves 68, 69 and the base valve 40.

When the flow rate further increases and the differential pressure exceeds the cracking pressure of the back valve 5 which is the first pressure side leaf valve, the pressure flows from the back valve 5 through the first pressure port 2a.
The damping force at this time is a combined characteristic of the variable orifice 77, the leaf valves 68 and 69, the rear valve 5, and the base valve 40.

Further, in the low speed range, the variable orifice 77,
The damping force is determined by each of the leaf valves 68 and 69 and the base valve 40, and the characteristic of the back valve 5 which is the first pressure side leaf valve is combined in the high speed range, and this characteristic is shown by a graph Fc2 in FIG.

Next, the variable orifice 77 and the variable port 7
Half-opening 8, 79 gives a medium damping force.

The operation is the same as that in the above-described soft operation for both the extension side and the compression side.

However, since the areas of the variable orifice 77 and the variable ports 78 and 79 are small, the piston speed reaching the cracking pressure of each valve has moved to the low speed region, and the characteristics on the extension side and the pressure side are respectively. It is shown by Fr3 in FIG. 2 and Fc3 in FIG.

At this time, since the variable orifice 77 is small, a large damping force difference can be obtained in the low speed range as compared with the characteristic when the variable orifice 77 is not provided.

As described above, when the practical range is set to the medium speed range, the rear side valve which is the first pressure side leaf valve when the pressure side is hard is provided by the high cut characteristic by the first extension side leaf valve 10 when the extension side is hard. The damping force is determined by the sum of the high cut characteristics of 5 and the base valve 40, and is independently determined by the second leaf valve 68 and the variable orifice 77 when the extension side is soft.

Although the damping force is determined by the combination of the variable orifice 77 and the second expansion / compression leaf valves 68 and 69 even when the compression side is soft, the combination is achieved by appropriately selecting the characteristics of the second compression side leaf valve 69. The specified characteristics can be set arbitrarily.

Further, since the variation width of the damping force can be set with a high damping force and a low damping force by a single valve, a large value can be obtained and a low damping force can be almost linear.

Further, by combining the valves having the frequency characteristics, only the practical range in the case of the hardware is made to have a high damping force, and other than that, it is self-variable to a low damping force to further improve the riding comfort.

Although the variable orifice 77 is provided in the embodiment shown in FIG. 1, it can be used without the second bypass port 71 and variable orifice 77.

In this case, the characteristics of the second expansion / compression leaf valves 68 and 69 can be obtained from the low speed range.

In the embodiment of FIG. 1, the plug 70 in which the passage 70 in the piston rod 3 is fitted to the lower portion of the piston rod 3
Although it is sealed with, it is possible to omit installation by integrally processing the piston nut.

That is, as shown in the embodiment of FIG. 4, a piston nut 4a, which is a valve housing, is screwed to the lower part of the piston rod 3, and the piston nut 4a is provided with a leaf valve 10, which is an expansion side damping valve. A chamber D communicating with C and a bypass passage 70 in the piston rod 3 is provided. The chambers C and D are partitioned by a partition wall 80. The chamber D is one or more ports 7 formed in the piston nut 4a in the radial direction.
It communicates with the lower oil chamber B via 5a.

In this case, the plug P is not used and the chamber D directly communicates with the passage 70 in the piston rod 3.

The upper end of the piston nut 4a directly abuts on the lower end seat portion of the piston 2 and passes through the first extension port 2 through the passage 4
It communicates with b.

Other configurations, operations, and effects are the same as those of the embodiment shown in FIG. 1, and the detailed description thereof will be omitted by giving the main reference numerals.

FIG. 5 shows another embodiment of the present invention.

In this embodiment, the piston nut 4a has the same construction as that of the embodiment of FIG. 4, and the piston rod 3 is provided with a passage 70 as a bypass and a rotary valve as a valve for opening and closing this bypass.

That is, the structure of the embodiment of FIG.
A piston rod 3 is movably inserted therein through a piston 2, the piston 2 defines two upper and lower oil chambers A and B in the cylinder 1, and the piston 2 communicates the two oil chambers A and B with each other. The first extension port 2b and the first pressure port 2a are formed, and a piston nut 4b, which is a valve housing, is provided below the piston rod 3, and the piston nut 4b is provided.
A passage 4b for communicating the first extension port 2b with the lower oil chamber B is provided in b, and a leaf valve 10 as an extension side damping valve for varying the damping force depending on the vibration frequency is provided in the middle of the passage 4b. Is provided so that it can be opened and closed, and the first pressure port 2a
A first pressure side leaf valve 5 is provided at the upper end of the open / close portion so as to be openable / closable.

Further, the piston rod 3 is provided with a passage 70 as a bypass communicating with the upper oil chamber A. This bypass communicates with the lower oil chamber B through a port 75a formed in the valve housing and further into the piston rod 3. Is provided with a valve 15 for adjusting the opening area of the bypass.

As in the other embodiment of FIG. 4, a piston nut 4a, which is a valve housing, is screwed to the lower portion of the piston rod 3, and the piston nut 4a is provided with a leaf valve 10, which is an expansion side damping valve. A chamber D communicating with C and a bypass passage 70 in the piston rod 3 is provided. The chambers C and D are partitioned by a partition wall 80. The chamber D is one or more ports 7 formed in the piston nut 4a in the radial direction.
It communicates with the lower oil chamber B via 5a.

In this case, the plug P of FIG. 1 is not used,
The chamber D communicates directly with the passage 70 in the piston rod 3.

Further, in the embodiment of FIG. 5, the piston rod 3 is provided with ports 81, 82, 83 communicating with the upper oil chamber A,
The ports 81, 82, 83 are communicated with the passage 70 that is a bypass in the piston rod 3.

A rotary valve 15, which is a valve driven by a control rod 20, is rotatably inserted into the piston rod 3, and a port 8 is inserted into the rotary valve 15.
Variable orifices 84, 85 facing 1, 82, 83,
One or a plurality of 86 are formed, and the opening areas of the ports 81, 82, and 83 are adjusted by rotating the rotary valve 15.

When the ports 81, 82 and 83 are opened and closed at the same time, the opening area of the passage 70, which is a bypass, is adjusted to obtain a hard damping force when fully closed, a medium damping force when intermediately opened, and a soft damping force when fully opened.

The other operations and effects are the same as those of the embodiment shown in FIGS. 1 and 4, and the same reference numerals are given to omit the details.

[0099]

According to the present invention, the following effects can be obtained.

A bypass is provided in parallel with the first expansion side damping valve and the first pressure side leaf valve on the piston rod side, and the opening area of the bypass is controlled by the valve. It is possible to obtain a large difference in damping force from high to high speed range, and also a large difference in high damping force and low damping force.

Similarly, the characteristic of the low damping force can be made a relatively linear characteristic instead of the square characteristic, and at the same time, the hard and soft characteristics at the time of extension and at the time of compression can be set independently.

Since the first extension-side damping valve that varies the extension-side damping force characteristics depending on the vibration frequency of the generated damping force is used, a high cut is performed for road surface input even during attitude control during hard times. The characteristics can be obtained and the riding comfort can be improved.

If the base valve is also used and a pressure side leaf valve having a high cut characteristic is provided in the base valve, the same effect can be obtained even when the pressure side is set.

Similarly, since the extension side damping valve that varies the damping force depending on the frequency is used, the posture control can be performed by three-step control without continuously varying the damping force at high speed.

Similarly, since it is not necessary to control a valve such as a rotary valve in accordance with the input frequency, the switching frequency of the damping force by the valve can be greatly reduced.
The durability is improved.

When a piston nut is used as the valve housing, and a chamber for arranging the damping valve and a chamber for communicating with the bypass are provided in the piston nut for integral molding, a plug or the like for sealing the bypass becomes unnecessary, and workability is improved. Also, the assemblability is improved, and it is also advantageous in economic efficiency.

[Brief description of drawings]

FIG. 1 is a partially cutaway vertical front view of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a graph showing a damping force characteristic on the extension side.

FIG. 3 is a graph showing damping force characteristics on the compression side.

FIG. 4 is a partially cutaway vertical front view of a hydraulic shock absorber according to another embodiment of the present invention.

FIG. 5 is a partially cutaway vertical front view of a hydraulic shock absorber according to another embodiment of the present invention.

[Explanation of symbols]

 1 Cylinder 2 Piston 2a First Pressure Port 2b First Extension Port 3 Piston Rod 4 Valve Housing Piston Nut 4a Valve Housing Piston Nut 4b Passage 5 First Pressure Side Leaf Valve Rear Valve 10 Extension Side Damping Valve Barrel Leaf Valve 15 Valve as rotary valve 23 Disc 66 Second expansion port 67 Second pressure port 68 Second expansion leaf valve 69 Second compression leaf valve 70 Bypass passage 71 Second bypass port 72 First Bypass port 73 First bypass port 74 port 75 port 75a port A, B Oil chamber

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[Procedure amendment]

[Submission date] May 31, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The hydraulic shock absorber of 9237 has the above effect,
Since a valve that generates damping force depending on the frequency is not provided, when varying the damping force according to the input frequency, the rotary valve is turned from outside each time via an actuator to reduce the damping force. Since it is necessary to switch the valve, the operability and responsiveness are inferior.Furthermore, not only the actuator but also the rotary valve is frequently used, durability becomes a problem, and the durability of the control rod and seal that holds this is required. There is a problem.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

On the other hand, in the hydraulic shock absorber disclosed in Japanese Patent Laid-Open No. 142941/1990, although a low damping force can be obtained at high frequency input due to the high cut characteristic, the damping force remains at the secondary resonance point, so that the unsprung flutter is suppressed. However, there is a problem in that the riding comfort in the soft damping force region cannot be improved because a large difference between the high damping force and the low damping force cannot be obtained.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

Thus, the leaf valve 10 is sandwiched between the annular rib 8e of the support member 8 and the annular rib 9e of the valve seat 9 from above and below by the restoring force of the leaf spring 63, and the inner periphery of the leaf valve 10 is The upper surface is in pressure contact with the seat portion 9f on the lower surface of the inner periphery of the valve seat 9,
Normally, the annular groove 9d formed between the annular rib 9e of the valve seat 9 and the seal portion 9f is closed, and the upper hydraulic oil chamber A is
From the passage 2f on the upper surface of the piston 2 to the extension side port 2b-the passage 4b of the piston nut 4-the opening 1 of the cap-shaped member 16.
6b- and valve seat 9b-The relief valve 10 prevents the lower hydraulic oil chamber B from passing through the annular groove 9d.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0035

[Correction method] Change

[Correction content]

A common passage 76 communicating with the second extension port 66 and the pressure port 67 is formed in the disk 23, and the passage 76 is formed in the ports 72, 7 formed in the piston rod 3.
3 is connected to the passage 70.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

The rotary valve 15 is provided with one or a plurality of variable orifices 77 facing the second bypass port 71 and variable ports 78, 79 facing the first bypass ports 72, 73. By rotating the valve 15, the variable orifice 77 and the variable ports 78 and 79 are controlled to the fully opened, half-opened, and fully opened states to generate hard, medium, and soft damping forces, respectively.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Change

[Correction content]

Therefore, if the vibration frequency during the extension stroke is equal to or lower than the vibration frequency set by the orifice 61 at that time, the generated hydraulic pressure in the upper working chamber A (=
The expansion side damping force) acts on the first-order lag pressure chamber R through the orifice 61 to push down the push member 11 to bend the inner peripheral end side of the leaf valve 10 downward,
The initial load is increased to generate a predetermined damping force, but when the vibration frequency in the extension stroke exceeds the value set by the orifice 61, the hydraulic pressure generated in the upper working chamber A is transmitted to the primary delay pressure chamber R through the orifice 61. Since the piston 2 has moved to the compression stroke before and the so-called orifice 61 has a first-order lag action, the hydraulic pressure in the first-order lag pressure chamber R does not rise and is kept at a low value, and the push member 11
Does not bend the inner peripheral end side of the leaf valve 10 downward while maintaining the raised position by the spring force of the leaf spring 13, the generated damping force becomes lower than a predetermined value, and a frequency-dependent hydraulic pressure with a high cut effect is obtained. Acts as a shock absorber.

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Drawing

[Correction method] Change

[Correction content]

[Figure 1]

Claims (5)

[Claims] 1. A first extension port for movably inserting a piston rod into a cylinder through a piston, the piston defining two upper and lower oil chambers in the cylinder, and the piston extending between the two oil chambers. And a first pressure port is formed, a valve housing is provided in the lower part of the piston rod, and a passage that connects the first extension port to the lower oil chamber is provided in the valve housing. An extension-side damping valve that varies the damping force depending on the vibration frequency is provided so as to be openable and closable, and a first pressure-side leaf valve is provided at the upper end of the first pressure port so that the piston rod can be opened and closed. Is provided with a bypass communicating with the upper oil chamber, this bypass communicates with the lower oil chamber through a port formed in the valve housing, and a valve for adjusting the opening area of the bypass in the piston rod. A damping force adjusting device for a hydraulic shock absorber, comprising: 2. A first extension port that movably inserts a piston rod into a cylinder via a piston, and the piston defines two upper and lower oil chambers in the cylinder, and the piston communicates the two oil chambers. And a first pressure port is formed, a valve housing is provided in the lower part of the piston rod, and a passage that connects the first extension port to the lower oil chamber is provided in the valve housing. An extension-side damping valve that varies the damping force depending on the vibration frequency is provided so as to be openable and closable, and a first pressure-side leaf valve is provided at the upper end of the first pressure port so as to be opened and closed. A disc is provided on the outer circumference of the piston rod, and this disc has a second extension port and a second extension port that open to the upper oil chamber.
Pressure port is formed, and a second expansion side leaf valve and a second compression side leaf valve are provided at the mouth ends of the second expansion port and the second pressure port respectively so as to be openable and closable, and the disc and the piston rod are provided. Is provided with a first bypass that connects the second extension port and the second pressure port to a bypass in the piston rod, and a valve that adjusts the opening area of the first bypass is provided in the piston rod. The damping force adjusting device for a hydraulic shock absorber, wherein the bypass in the piston rod communicates with a lower oil chamber through a port formed in the valve housing. 3. The piston rod is provided with a second bypass that communicates the upper oil chamber with a bypass in the piston rod, and the opening area of the second bypass is adjusted by a variable orifice provided in the valve. A damping force adjusting device for a hydraulic shock absorber as described. 4. The bypass in the piston rod is sealed by a plug fitted to the lower part of the piston rod, and the bypass communicates with the lower oil chamber via a radial port provided in the piston rod and the valve housing. The damping force adjusting device for a hydraulic shock absorber according to claim 2. 5. The valve housing is formed of a piston nut, and the piston nut is provided with a first chamber for arranging an extension side damping valve and a second chamber for communicating with a bypass of a piston rod, and the second chamber is The damping force adjusting device for a hydraulic shock absorber according to claim 1 or 2, which communicates with the lower oil chamber via a port formed in the piston nut in a radial direction.