JP3128704B2 - Damping force adjustable hydraulic shock absorber - Google Patents

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 type hydraulic shock absorber used for a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art Hydraulic shock absorbers used in suspension systems of vehicles such as automobiles are provided with a damping force that can be appropriately adjusted according to road surface conditions, running conditions, etc., in order to improve ride comfort and steering stability. There is a damping force adjustable hydraulic shock absorber.

Conventionally, as this kind of damping force adjusting type hydraulic shock absorber, for example, there is one disclosed in Japanese Utility Model Laid-Open Publication No. 61-190048. In this method, a piston is slidably fitted in a cylinder filled with an oil liquid, and two chambers in the cylinder defined by the piston are provided along a main oil liquid passage and a piston rod formed in the piston. And a damping force adjusting valve for opening and closing the bypass passage. An orifice (large flow resistance) and a disk valve are provided in the main oil liquid passage, and an orifice (small flow resistance) is provided in the bypass passage.

[0004] With this configuration, the damping force is generated by controlling the flow of the oil liquid in the main oil liquid passage or the bypass passage caused by sliding of the piston. By opening and closing the bypass passage with the damping force adjusting valve, the damping force can be adjusted between the hard side and the soft side. When the bypass passage is closed (hard side), a large damping force is generated by the orifice (large flow resistance) of the main oil passage and the disc valve. On the other hand, when the bypass passage is opened (in the case of the soft side), a small damping force is generated by the orifice (small damping force) of the bypass passage. And the disc valve in the main oil passage opens, and a damping force is generated by the disc valve.
Therefore, as shown in FIG. 5, when the piston speed is low, the difference in damping force between the hard side (see the solid line) and the soft side (see the broken line) is large due to different orifice characteristics, as shown in FIG. When the piston speed is high, the difference in damping force between the hard side and the soft side is small due to the same disk valve characteristics.

[0005]

As described above, in the above-mentioned conventional damping force adjusting type hydraulic shock absorber, the damping force is adjusted by changing the characteristics of the orifice, and the characteristics of the disc valve are not changed. There is a problem that it is difficult to set a large difference in damping force between the hard side and the soft side when the speed is high.

The present invention has been made in view of the above points, and has as its object to provide a damping force-adjustable hydraulic shock absorber in which the damping force characteristics can be adjusted by switching the characteristics of a disc valve. .

[0007]

In order to solve the above-mentioned problems, a damping force-adjustable hydraulic shock absorber according to the present invention is slidable on a cylinder (1) filled with oil and the cylinder (1). Piston that is fitted into the cylinder and partitions the inside of the cylinder (1) into two chambers (1a, 1b)
(2) and one end of the cylinder connected to the piston (2).
A piston rod (3) extending to the outside of (1), the piston (2) being provided with one end open near the outer periphery thereof, the two chambers;
(1a, 1b) and a first oil liquid passage (5, 6) communicating with the first oil liquid passage (5, 6) in the piston (2). A second oil liquid passage (9, 11) provided to communicate the two chambers (1a, 1b), and an end of the piston (2) facing the first oil liquid passage (5, 6). The second oil liquid passage (9, 1
The first oil liquid passage having a communication passage (14, 18) communicating with the first oil liquid passage;
(5, 6) a first disc valve (12, 16) for controlling the flow of the oil liquid to generate a damping force, the first disc valve (12, 16)
The second oil liquid passage provided facing the communication passage (14, 18) of the first disc valve (12, 16) in a state where the second oil liquid passage is
(9, 11) The second to control the flow of the oil liquid to generate damping force
A disk valve (15, 19), comprising a damping force adjusting valve (22) for opening and closing the first or second oil liquid passage (9, 11 or 5, 6) , the first and second disks Valves (12,16 and 15,1
9), the oil liquid passage (9, 1) having the damping force adjusting valve (22).
(1 or 5, 6) to open the other valve
It is characterized in that it is reduced with respect to pressure .

[0008]

With such a construction, when the second oil passage is closed by, for example, the damping force adjusting valve, the oil flows through the first oil passage along with the sliding of the piston and the first disk is moved. When a damping force is generated by the valve and the second oil liquid passage is opened, the oil liquid flows through the second oil liquid passage as the piston slides, and a damping force is generated by the second disk valve.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. 1 and 2 show the main part of the damping force-adjustable hydraulic shock absorber of the present embodiment. In the drawings, the right side of the drawing shows a contraction stroke, and the left side shows an extension stroke.

As shown in FIGS. 1 and 2, a piston 2 is slidably fitted in a cylinder 1 in which an oil liquid is sealed, and the piston 2 causes the inside of the cylinder 1 to be in a cylinder upper chamber 1a and a cylinder lower chamber 1a. It is divided into two rooms, a room 1b. A proximal end of a piston rod 3 whose distal end extends to the outside of the cylinder 1 penetrates through the piston 2 and is fixed by a nut 4.

The piston 2 has a contraction-side first side communicating a cylinder upper chamber 1a and a cylinder lower chamber 1b at a portion near the outer periphery thereof.
The first oil liquid passage 5 and the extension-side first oil liquid passage 6 are formed. A bypass passage 7 is provided in the piston rod 3 along the axial direction. The bypass passage 7 has one end opening toward the cylinder lower chamber 1b and the other end including an oil liquid passage 7a.
Through the cylinder upper chamber 1a. Piston 2
One end of the piston passage 3 is opened toward the cylinder upper chamber 1a at a position near the inner periphery, and the other end is connected to a bypass passage 7 through an oil liquid passage 8 formed in a side wall of the piston rod 3 from the cylinder lower chamber 1b.
The second hydraulic fluid passage 9 and the other end open to the cylinder lower chamber 1b side, and the other end is bypassed through the hydraulic fluid passage 10 provided on the side wall of the piston rod 3 from the cylinder upper chamber 1a. An extension-side second oil liquid passage 11 communicating with the passage 7 is provided.

An end surface of the piston 2 on the side of the cylinder upper chamber 1a is provided with a contraction-side first disk valve 12 for controlling the flow of the oil in the contraction-side first oil passage 5 to generate a damping force during the contraction stroke. Is provided, and an orifice 13 is formed between the piston 2 and the first disc valve 12 on the compression side.
In addition, a communication passage 14 communicating with the contraction-side second oil liquid passage 9 is formed in the contraction-side first disk valve 12. Further, a small-diameter contraction-side second disk valve 15 that overlaps the contraction-side first disk valve 12 and controls the flow of the oil in the contraction-side second oil liquid passage 9 to generate a damping force is provided. ing. The compression-side second disk valve 15 is set to have a smaller valve opening pressure than the compression-side first disk valve 12. For reference, FIG. 3 shows an exploded perspective view of the piston 2, the contraction-side first disk valve 12, and the contraction-side second disk valve 15. 1 and 2, the contraction-side first disc valve 12 is a set of three discs, but in FIG. 3, it is shown as a set of two discs.

On the end surface of the cylinder lower chamber 1b of the piston 2,
An extension-side first disc valve that controls the flow of oil in the extension-side first oil-liquid passage 6 to generate a damping force during the extension stroke.
An orifice 17 is provided between the piston 2 and the extension-side first disc valve 16. The extension-side first disk valve 16 is provided with a communication passage 18 communicating with the extension-side second oil liquid passage 11. further,
A small-diameter extension-side second disk valve 19 that overlaps the extension-side first disk valve 16 and controls the flow of oil in the extension-side second oil liquid passage 11 to generate a damping force is provided. . The extension-side second disc valve 19 is connected to the extension-side first disc valve.
The valve opening pressure for the disc valve 16 is set small. In the figure, 20 is a spacer and 21 is a washer.

In the bypass passage 7 of the piston rod 3, there is provided a spool 22 constituting a damping force adjusting valve for opening and closing the bypass passage 7, the contraction-side second oil passage 9 and the extension-side second oil passage 11. It is slidably fitted. When the spool 22 is in the soft position shown in FIG. 1, the oil passage 7 of the bypass passage 7 is formed by a groove 22a formed in the center thereof.
a and the oil liquid passage 10 are communicated with each other, and the cylinder upper chamber 1a and the cylinder lower chamber 1b are communicated via the second oil liquid passage 11 on the extension side. In addition, the large-diameter portions 22b formed at both ends block the oil liquid passage 10 and the oil liquid passage 8 in the bypass passage 7 and connect the oil liquid passage 8 to the lower part of the cylinder via the distal end of the bypass passage 7. The upper cylinder chamber 1a and the lower cylinder chamber 1b are communicated with each other through the second hydraulic fluid passage 9 on the contraction side. On the other hand, at the hard side position shown in FIG. 2, the large-diameter portion 22b closes the oil passage 7a and the oil passage 8 so that the spool 22 closes the bypass passage 7, the second contraction-side second oil passage 9 and the extension side. The second oil passage 11 is closed.

A cylindrical stopper 23 is inserted and fixed at the end of the bypass passage 7. A spring for urging the spool 22 to the soft side between the stopper 23 and the spool 22 is provided.
24 are interposed. In the bypass passage 7, a rod 25 which is movably supported in the axial direction and abuts on the spool 22 is inserted. The rod 25 is moved by an actuator (not shown), and the spool 22 is moved by a spring. twenty four
To the hard side against the elastic force of In the drawing, a bush 26 slidably supports the rod 25 and regulates the movement of the spool 22.

The operation of the embodiment constructed as described above will now be described. When the spool 22 is moved to the hard side shown in FIG. 2 by the rod 25, the oil liquid passages 7a and 8 of the bypass passage 7 are closed by the spool 22, and the contraction side second
The oil liquid passage 9 and the extension-side second oil liquid passage 11 are closed. Therefore, during the contraction stroke, the oil liquid in the cylinder lower chamber 1b flows into the cylinder upper chamber 1a through the contraction-side first oil liquid passage 5. When the piston speed is low, a damping force (orifice characteristic) proportional to the piston speed in a quadratic curve is generated by the orifices 13 and 17, and when the piston speed is high, the first disk valve 12 on the compression side opens to reduce the piston speed. A linearly proportional damping force (valve characteristic) is generated. On the other hand, during the extension stroke, the oil liquid in the cylinder upper chamber 1a flows into the cylinder lower chamber 1b through the extension-side first oil liquid passage 6, and when the piston speed is low, the orifices 13, 17 secondarily reduce the piston speed. A damping force (orifice characteristic) proportional to a curve is generated, and when the piston speed is high, the extension-side first disk valve 16 opens to generate a damping force (valve characteristic) linearly proportional to the piston speed. That is, the damping force characteristic indicated by a solid line in FIG.

When the spool 22 is moved to the soft side shown in FIG. 1 by the rod 25, the oil liquid passage 7a of the bypass passage 7 and the oil liquid passage 10 are communicated by the groove 22a of the spool 22,
The cylinder upper chamber 1a and the cylinder lower chamber 1b are communicated via the extension side bypass passage 11. Also, the large diameter portion 22 of the spool 22
b, the oil liquid passage 10 side and the oil liquid passage 8 side in the bypass passage 7 are shut off, and the oil liquid passage 8 is communicated with the cylinder lower chamber 1b via the distal end portion of the bypass passage 7, and the contraction side bypass passage 9 through the cylinder upper chamber 1a and the cylinder lower chamber
Communicate with 1b. Therefore, during the contraction stroke, when the piston speed is low, the oil liquid in the cylinder lower chamber 1b flows into the cylinder upper chamber 1a through the contraction-side first oil liquid passage 5,
Damping force proportional to the piston speed as a quadratic curve by the orifices 13 and 17 as in the hard side (orifice characteristics)
When the piston speed is high, the contraction-side second disk valve 15 is opened by the pressure of the oil in the contraction-side second oil liquid passage 9 and is linearly proportional to the piston speed, and is smaller than the hard side. Damping force (valve characteristics) is generated. Also, during the extension stroke, when the piston speed is low, the oil liquid in the cylinder upper chamber 1a flows into the cylinder lower chamber 1b through the extension-side first oil liquid passage 6, and the orifices 13, 17 communicate with the hard side. Similarly, a damping force (orifice characteristic) proportional to the piston speed in a quadratic curve is generated, and when the piston speed is high, the expansion-side second disk valve is actuated by the pressure of the oil in the expansion-side second oil-liquid passage 11. 19 opens,
A damping force (valve characteristic) that is linearly proportional to the piston speed and smaller than the hard side is generated. That is, the damping force characteristic indicated by the broken line in FIG.

In this way, by switching the valve characteristics between the hard side and the soft side, the damping force characteristics can be adjusted.

In this embodiment, since the contraction-side second disk valve 15 and the extension-side second disk valve 19 are not provided with orifices, when the piston speed is low, the first oil liquid is used on both the hard side and the soft side. Passage orifice 13,1
7 shows the same orifice characteristics, but notches are provided in the contraction-side second disk valve 15 and the extension-side second disk valve 19 so that the contraction-side second oil liquid passage 9 and the extension-side second
By providing an orifice in the oil liquid passage 11, different orifice characteristics can be set between the hard side and the soft side.

In this embodiment, the second oil liquid passage 9,
The first oil liquid passages 5 and 6 are connected to the oil liquid passages 8 and 10, and the second oil liquid passages 9 and 11 are connected to the first oil liquid passages 9 and 11. Oil fluid passages 5 and 6 are displaced in the circumferential direction, and the other end is the cylinder lower chamber.
1b and the cylinder upper chamber 1a.
May be opened and closed by the spool 22. In this case, it is desirable to set the valve opening pressure of the first disk valves 12 and 16 smaller than the valve opening pressure of the second disk valves 15 and 19.

[0021]

As described in detail above, the damping force-adjustable hydraulic shock absorber of the present invention is provided with a first disc valve in the first oil passage and a second disc in the second oil passage. Since the valve is provided, for example, when the second oil liquid passage is closed, damping force is generated by the first disk valve, and when the second oil liquid passage is opened, the damping force is generated by the second disk valve. Occurs. As a result, it is possible to obtain damping force characteristics having different valve characteristics, and it is possible to easily set a large difference in damping force between the hard side and the soft side with respect to a case where the piston speed is high. Since the and the second disc valve are superimposed on each other, an excellent effect of being compact can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a software side state according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part showing a state of a hardware side of the apparatus of FIG. 1;

FIG. 3 is an exploded perspective view of a piston and a disc valve of the apparatus of FIG.

FIG. 4 is a diagram showing damping force characteristics of the device of FIG.

FIG. 5 is a diagram showing a damping force characteristic of a conventional damping force adjusting type hydraulic shock absorber.

[Explanation of symbols]

 Reference Signs List 1 cylinder 1a cylinder upper chamber 1b cylinder lower chamber 2 piston 3 piston rod 5 contraction-side first oil liquid passage 6 extension-side first oil liquid passage 7 bypass passage 9 contraction-side second oil liquid passage 11 extension-side second Oil passage 12 contraction side first disc valve 14 communication path 15 contraction side second disk valve 16 extension side first disk valve 18 communication path 19 extension side second disk valve 22 spool (damping force adjusting valve)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16F 9/44 F16F 9/348 B60G 17/08

Claims (1)

(57) [Claims] 1. A cylinder (1) filled with an oil liquid, and two chambers are slidably fitted to the cylinder (1) and slidably fitted in the cylinder (1).
(1a, 1b), a piston (2), a piston rod (3) connected to the piston (2), one end of which extends outside the cylinder (1), and an outer periphery of the piston (2). A first oil liquid passage (5, 6) which is provided with an open end and communicates with the two chambers (1a, 1b), and a first oil liquid passage (5, 6) connected to the piston (2). ), A second oil liquid passage (9, 11) provided with an open end near the center and communicating with the two chambers (1a, 1b), and the first oil liquid passage (9, 11) at the end of the piston (2). The communication passage (1) is provided facing the oil liquid passage (5, 6) and communicates with the second oil liquid passage (9, 11).
A first disk valve (12, 16) having an oil liquid flow in the first oil liquid passage (5, 6) to generate a damping force
And the second oil liquid passageway (14, 18) provided facing the communication passages (14, 18) of the first disk valve (12, 16) in a state of being superimposed on the first disk valve (12, 16). (9,11) The second disk valve (15,1) that controls the flow of the oil liquid to generate a damping force
9), and a damping force adjusting valve (22) for opening and closing the first or second oil liquid passage (9, 11 or 5, 6) .
Of the disc valves (12,16 and 15,19), the damping force
In the oil passage (9, 11 or 5, 6) with the adjustment valve (22)
One of the valve opening pressures is smaller than the other.
A damping force adjustable hydraulic shock absorber.