JPH06213267A - Damping force adjusting type hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To selectively change damping force characteristic to three ways, hard, medium, soft, by providing main disc valves to control flow of oil liquid in main oil liquid passages so as to generate damping force, and subdisc valves to control flow of oil liquid in a bypass passage so as to generate damping force. CONSTITUTION:When main oil liquid passages are opened and a bypass passage 37 is closed by means of a damping force adjusting valve 45, large damping force is generated by the valve characteristic of main disc valves 27, 31. When the main oil liquid passages 25, 26 are closed and the bypass passage 37 is opened, smaller damping force than the damping force due to the main disc valve 31 is generated by the valve characteristic of a subdisc valve 42. When both the main oil liquid passages and the bypass passage 37 are opened, the damping force compounded out of both damping force due to the main disc valve 27 and the subdisc vale 42 is generated, and the smaller damping force than the damping force due to the subdisc valves 42, 43 is generated. In this way, by rotating the shutter 45, the damping force is changed to the three ways of valve characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjustable hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

In a hydraulic shock absorber installed in a suspension system of a vehicle such as an automobile, a damping force can be appropriately adjusted in order to improve ride comfort and steering stability in accordance with road surface conditions, running conditions and the like. There is a force adjustable hydraulic shock absorber.

An example of a conventional hydraulic shock absorber of this type will be described with reference to FIG. As shown in FIG. 7, a conventional damping force adjustable hydraulic shock absorber 1 includes a cylinder 2 in which an oil liquid is sealed.
A piston 3 is slidably fitted therein, and the interior of the cylinder 2 is defined by the piston 3 into a cylinder upper chamber 2a and a cylinder lower chamber 2b. The piston 3 has
One end side of the piston rod 4 is connected, and the other end side of the piston rod 4 extends to the outside of the cylinder 2.

The piston 3 is provided with an extension-side main oil liquid passage 5 and a compression-side main oil liquid passage 6 which connect the cylinder upper chamber 2a and the cylinder lower chamber 2b to each other, and the extension stroke of the piston rod 4. Sometimes, the disc valve 7 (large damping force) that allows the flow of the oil liquid in the extension side main oil liquid passage 5 to generate the damping force and the flow of the oil liquid in the contraction side main oil liquid passage 6 during the compression stroke A disc valve 8 (a large damping force) for generating a damping force is provided.

The piston rod 4 is provided with a bypass passage 9 for connecting the cylinder upper chamber 2a and the cylinder lower chamber 2b. The bypass passage 9 is provided at the tip of the piston rod 4 when the piston rod 4 extends. A sub-valve mechanism 10 having a disk valve 10a for allowing the oil liquid to flow and generating a damping force and a check valve 10b for allowing the oil liquid to flow in the bypass passage 9 during the compression stroke is attached. Further, the piston rod 4 has a bypass passage 9
A shutter 11 for opening and closing the
The bypass passage 9 can be opened and closed by externally operating the shutter 11 to rotate the shutter 11.

Next, the operation of the damping force adjusting hydraulic shock absorber 1 will be described. When the bypass passage 9 is closed by the shutter 11, the piston 3 is expanded and contracted by the piston rod 4.
The oil in the cylinder 2 slides and the main oil liquid passage 5
Alternatively, a large damping force is generated in the valve characteristics by flowing through the contraction side main oil liquid passage 6 and by the disk valves 7 and 8. Therefore, the damping force characteristic becomes a hard characteristic.

Further, when the bypass passage 9 is opened, the oil liquid in the cylinder 2 flows through the bypass passage 9 due to the sliding of the piston 3, and a small damping force is generated by the sub valve mechanism 10 in terms of valve characteristics. At this time, when the piston speed is high and the pressure difference between the cylinder upper chamber 2a and the cylinder lower chamber 2b is large, the disc valves 7 and 8 are opened and the expansion side main oil liquid passage 5 or Since the oil liquid flows through the contraction-side main oil liquid passage 6, the damping force has a characteristic that combines the damping force characteristics of the bypass passage 9 and the extension-side main oil liquid passage 5 or the contraction-side main oil liquid passage 6. Therefore, the damping force characteristic becomes a soft characteristic.

In this way, by opening and closing the bypass passage 9 by the shutter 11, it is possible to obtain damping force characteristics of two types of valve characteristics, a hard characteristic for generating a large damping force and a soft characteristic for generating a small damping force. it can.

[0009]

However, in the conventional damping force adjusting hydraulic shock absorber 1 shown in FIG. 7, the piston 3 is used.
Since the extension side main oil liquid passage 5 and the contraction side main oil liquid passage 6 are always communicated with each other, even if the bypass passage 9 is opened and the soft characteristic is selected, the disc valves 7 and 8 are opened when the piston speed is high. Then, the oil liquid flows through the extension-side main oil liquid passage 5 or the contraction-side main oil liquid passage 6 in addition to the bypass passage 9, and the damping force characteristic is a combined characteristic thereof. Therefore, the damping force characteristic on the hard side affects the damping force characteristic on the soft side, and there is a problem that the damping force characteristics for both expansion and contraction do not match the set soft characteristic.

The present invention has been made in view of the above points, and provides a damping force adjustable hydraulic shock absorber capable of selectively opening and closing the main oil liquid passage and the bypass passage. To do.

[0011]

In order to solve the above-mentioned problems, a damping force adjustable hydraulic shock absorber of the present invention is provided with a cylinder in which an oil liquid is sealed, and a cylinder fitted inside the cylinder. A piston defining two chambers, a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, a main oil liquid passage communicating the two chambers of the cylinder, and the main oil. A main disk valve that controls the flow of the oil liquid in the liquid passage to generate a damping force;
A bypass passage that communicates the chambers, a sub-disk valve that controls the flow of oil liquid in the bypass passage to generate a damping force, and a damping force control valve that selectively opens and closes the main oil liquid passage and the bypass passage, respectively. It is characterized by comprising.

[0012]

With this configuration, when the damping force adjusting valve opens the main oil liquid passage and closes the bypass passage, a damping force having a valve characteristic due to the main disc valve is generated, closing the main oil passage and closing the bypass passage. When opened, a damping force of the valve characteristic due to the sub-disk valve is generated, and when both the main oil passage and the bypass passage are opened, a damping force of the valve characteristic of the combined characteristic due to the main disc valve and the sub-disk valve is generated. The damping force characteristic of the valve characteristic can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, in the damping force adjusting type hydraulic shock absorber 13, a piston 15 is slidably fitted in a cylinder 14 in which an oil liquid is sealed. Is the upper chamber 14a of the cylinder and the lower chamber 14b of the cylinder.
It is defined in the room. Piston 15 has a piston rod
One end side of the piston 16 is penetrated, and the piston rod 16 has a cylindrical passage member 17 screwed on the tip end thereof so that the piston 3
Installed on. The other end of the piston rod 16 is a rod guide (not shown) provided at the end of the cylinder 14.
And, it extends to the outside of the cylinder 14 through a seal member (not shown). Further, the cylinder 14 is provided with a reservoir chamber (not shown) for compensating the volume change in the cylinder due to the entry and the exit of the piston rod 16 by compressing and expanding the gas.

The piston 15 is a piston body having a substantially bottomed cylindrical shape.
18 and a partition member fitted to an intermediate portion in the piston body 18
19 and valve body fitted into the opening of piston body 18
20 and these are penetrated at one end side of the piston rod 16 so that the step portion 16a of the piston rod 16 and the piston rod 16
It is sandwiched by a passage member 17 screwed to the tip end of 16 and integrally connected. In the figure, 21 and 22 are washers, and 23 and 24 are retainers. Then, the partition member 19 causes the piston
The interior of 15 is partitioned into a chamber 15a on the valve body 20 side and a chamber 15b on the bottom side of the piston body 18. Piston body
A valve body 18a is formed at the bottom of the valve 18.

The valve body 20 of the piston 15 is provided with a compression side communication passage 25 on the inner peripheral side thereof for communicating the cylinder upper chamber 14a with the chamber 15a inside the piston 15, and the cylinder upper chamber is provided on the outer peripheral side thereof. Extension side communication passage that connects 14a and chamber 15a
26 are provided. On the end surface of the valve body 20 on the cylinder upper chamber 14a side, a main disk valve 27 that allows the oil liquid to flow from the chamber 15a side of the compression side communication passage 25 to the cylinder upper chamber 14a side to generate a damping force. Is provided. Further, a check valve 28 is provided on the end surface of the valve body 20 on the chamber 15a side, which allows only the flow of the oil liquid from the cylinder upper chamber 14a side of the extension side passage 26 to the chamber 15a side. As shown in FIG. 2, the check valve 28 is provided with a notch 28a at a position facing the opening of the contraction side communication passage 25 on the inner peripheral side thereof to prevent the oil liquid from flowing through the contraction side communication passage 25. It does not interfere.

The valve body portion 18a of the piston 15 is provided with an extension side communicating passage 29 for communicating the cylinder lower chamber 14b and the chamber 15b in the piston 15 on the inner peripheral side thereof, and the extension side communicating passage 29 is provided on the outer peripheral side thereof. A contraction side communication passage 30 that communicates the chamber 14b and the chamber 15b is provided. The end of the valve body 18a on the cylinder lower chamber 14b side has a chamber 15 of the extension side communication passage 29.
A main disk valve 31 is provided which allows the oil liquid to flow from the b side to the cylinder lower chamber 14b side to generate a damping force. A check valve 32 is provided on the end surface of the valve body portion 18a on the chamber 15b side, which allows only the flow of the oil liquid from the cylinder chamber lower chamber 14b side to the chamber 15b side of the compression side communication passage 30. The check valve 32 is the chuck valve 28 described above.
Similarly, the notch 32a is provided at a portion facing the opening of the extension side communication passage 29 on the inner peripheral side so as not to obstruct the circulation of the oil liquid in the extension side communication passage 29.

The partition member 19 of the piston 15 has one end that opens into the chamber 15a and the chamber 15b in the piston 15, and the other end that opens toward the side surface of the piston rod 16 that passes through the partition member 19. Passageways 33 and 34 are provided. The oil liquid passages 33 and 34 communicate with the ports 35 and 36 of the piston rod 16 described later, respectively.

The piston rod 16 is provided with a bypass passage 37 which extends along the axis of the piston rod 16 and connects the cylinder upper chamber 14a and the cylinder lower chamber 14b to each other. Bypass passage
37 has one end opened to the inside of the passage member 17 in the cylinder lower chamber 14b, and the other end communicated with the cylinder upper chamber 2a via a port 38 provided along the radial direction of the piston rod 16. The side wall of the piston rod 16 forming the bypass passage 37 is provided with ports 35 and 36 communicating with the oil liquid passages 33 and 34 provided in the partition member 19 of the piston 15, respectively.

A valve body 39 is attached to the opening of the passage member 17. The valve body 39 has an extension side communication passage 40 and a compression side communication passage 40 for communicating the inside of the passage member 17 with the cylinder lower chamber 14a. A passage 41 is provided. At the end surface of the valve body 39 on the cylinder lower chamber 14b side, the extension side communication passage is formed.
A sub-disk valve that allows the passage of oil liquid from the inside of the passage member 17 of 40 to the cylinder lower chamber 14b side to generate a damping force.
42 are provided. In addition, the passage member 17 of the valve body 39
The end surface facing the inside of the
A sub disk valve 43 is provided that allows the oil liquid to flow from the 14b side to the inside of the passage member 17 to generate a damping force. The sub-disk valves 42 and 43 are sandwiched and fixed between the sub-disk valves 42 and 43 by the pin 44 penetrating the valve body 39. The sub disk valves 42 and 43 are set to have a valve opening pressure lower than that of the main disk valves 27 and 31, that is, to generate a small damping force.

In the bypass passage 37, a shutter 45 having a cylindrical shape with a lid is rotatably fitted as a damping force adjusting valve, and an operating rod 46 is connected to the lid of the shutter 45. The operating rod 46 is extended along the piston rod 16 and protrudes from the tip of the piston rod 16 extended to the outside of the cylinder 14 by the operating rod 46, and the damping force adjusting hydraulic shock absorber 13 is provided. The shutter 45 can be rotated from outside. In the figure, 47 is a thrust washer and 48 and 49 are bushes.

On the side wall of the shutter 45, a port 50 is provided at a portion facing the port 38 of the bypass passage 37,
The bypass passage 37 can be opened and closed depending on whether or not the shutter 45 is rotated to align the port 50 with the port 38.

Further, on the outer periphery of the shutter 45, a communication groove for communicating the port 35 with the port 36 is provided at a portion facing the port 35 and the port 36 provided on the side wall of the piston rod 16.
51 is provided to rotate the shutter 45 to
The port 35 and the port 36 can be communicated with each other or blocked depending on whether or not the communication groove 51 is aligned with the port 36. Then, by communicating the port 35 and the port 36 with the communication groove 51, the chamber 15a and the chamber 15b in the piston 15 are communicated.
Through the expansion side communication passage 26 of the valve body 20 and the expansion side communication passage 29 of the valve body portion 18a, and the contraction side communication passage 25 of the valve body 20 and the contraction side communication passage of the valve body portion 18a. Cylinder upper chamber 14a and cylinder lower chamber 1 through 30
It is connected to 4b. That is, the chamber 15a, the chamber 15b, the contraction side communication passage 25 and the expansion side communication passage 26 of the valve body 20, the expansion side communication passage 29 and the contraction side communication passage 30 of the valve body portion 18a, the oil liquid passage 33 of the partition member 19, 34, Piston rod ports 35, 36
And the communication groove 51 of the shutter 45 allows the upper chamber 14a of the cylinder.
A main oil liquid passage that connects the cylinder lower chamber 14b and the cylinder lower chamber 14b is configured, and the main oil liquid passage can be opened and closed by rotating the shutter 45.

Further, the positions of the ports 38 of the piston rod 16 and the port 50 of the shutter 45 that open and close the bypass passage 37, and the communication grooves 51 of the ports 35 and 36 of the piston rod 16 and the shutter 45 that open and close the main oil passage. The positions of and are arranged as shown in FIG. 3, and the shutter 45 is shown in FIG.
3B, the bypass passage 37 is closed and the main oil liquid passage is opened, and when it is in the position (B) of FIG. 3, the bypass passage is opened.
When 37 is opened and the main oil liquid passage is closed, when the position (C) is set, both the bypass passage 37 and the main oil liquid passage are opened. Thus, in the present invention, each of the bypass passage 37 and the main oil liquid passage can be selectively opened and closed.

The operation of the present embodiment thus constructed will be described below with reference to FIGS. 4 to 6. Note that FIG.
6 to 6, the left side of the drawing shows the expansion stroke of the piston rod 16, the right side shows the compression stroke of the piston rod 16, and the arrows in the figure show the main flow paths of the oil liquid. There is.

When the operation rod 46 is operated from the outside of the damping force adjusting hydraulic shock absorber 13 to move the shutter 45 to the rotational position shown in FIG. 3A, the bypass passage 37 is closed as shown in FIG. The oil passage opens. Therefore, the piston rod 16
During the expansion stroke, the oil in the cylinder upper chamber 14a is pressurized as the piston 15 slides, flows through the extension side communication passage 26 of the valve body 20 and pushes open the check valve 28 to open the chamber 15a.
, Oil liquid passage 33, port 35, communication groove 51, port 36, oil liquid passage 34, chamber 15b, notch 32a of check valve 32,
It flows through the extension side communication passage 29 of the valve body portion 18a, pushes and opens the main disk valve 31, and flows into the cylinder lower chamber 14b. At this time, the main disc valve 31 generates a large damping force in terms of valve characteristics.

Further, during the compression stroke of the piston rod 16, the oil liquid in the cylinder lower chamber 14b is pressurized as the piston 15 slides, and flows through the compression side communication passage 30 of the valve body 18 to open the check valve 32. Push open, chamber 15b, oil passage 3
4, port 36, communication groove 51, port 35, oil passage 33, chamber 15a
, Pass through the cutout 28a in the check valve 28, and
Flows through the compression side communication passage 25, pushes and opens the main disk valve 27, and flows into the cylinder upper chamber 14a. At this time, the main disc valve 27 produces a large damping force in terms of valve characteristics.

As described above, since the oil liquid in the cylinder 14 flows through the main oil liquid passage and a large damping force is generated by the main disk valves 27 and 31 during both the expansion and contraction strokes, the damping force characteristic becomes a hard characteristic. .

When the shutter 45 is set to the rotational position shown in FIG. 3B, the bypass passage 37 is opened and the main oil liquid passage is closed as shown in FIG. Therefore, as shown in FIG. 5, during the expansion stroke of the piston rod 16, the oil liquid in the cylinder upper chamber 14a is pressurized as the piston 15 slides, and the port 3
8, the port 50, the shutter 45, the bypass passage 37, and the passage member 17, and further flows through the extension side communication passage 40 of the valve body 39, pushes the sub disk valve 42 open, and flows into the lower cylinder chamber 14b. At this time, the sub disk valve
Due to the valve characteristic, a damping force smaller than that of the main disc valve 31 is generated by the valve 42.

Further, during the compression stroke of the piston rod 16, the oil liquid in the cylinder lower chamber 14b is pressurized as the piston 15 slides, and flows through the compression side communication passage 41 of the valve body 39 to drive the sub disk valve 43. Push open, further, passage member
The gas flows into the cylinder upper chamber 14a through the inside of 17, the bypass passage 37, the inside of the shutter 45, the port 50 and the port 38. At this time, the sub-disk valve 43 generates a damping force smaller than the damping force of the main disk valve 27 due to the valve characteristic.

In this way, during the expansion and contraction strokes, the oil liquid in the cylinder 14 circulates through the bypass passage 37, and the sub-disk valves 42, 43 generate a damping force smaller than that by the main disk valves 27, 31. Therefore, the damping force characteristic becomes a medium characteristic.

When the shutter 45 is in the rotational position shown in FIG. 3C, both the bypass passage 37 and the main oil liquid passage are opened as shown in FIG. Therefore, as the piston slides due to the expansion and contraction of the piston rod 16, the oil liquid in the cylinder 14 flows through the main oil liquid passage and the bypass passage 37 in the same manner as in the cases shown in FIGS. 4 and 5. At this time, damping force is applied to the main disk valves 27, 31 and the sub disk valves.
A damping force that combines the damping forces of both 42 and 43, and the damping force of the sub-disk valves 42 and 43 (medium characteristic)
A smaller damping force is generated. Therefore, the damping force characteristic becomes a soft characteristic.

As described above, by operating the operating rod 46 and rotating the shutter 45, the damping force characteristic can be switched to one of three valve characteristics: hard, medium and soft. At this time, at the time of the hard characteristic and the soft characteristic, since the oil liquid flows through only one of the main oil liquid passage and the bypass passage, the damping force characteristics on the hard side and the soft side do not affect each other, and thus the damping force characteristic Greater flexibility in setting.

In this embodiment, the main disc valve 2
Although the damping force of the valve characteristic is generated by the 7, 31 and the sub-disk valves 42, 43, the valve characteristic and the orifice can be obtained by providing the orifices that constantly communicate the upstream side and the downstream side of these disk valves. It is also possible to obtain both damping force characteristics.

[0035]

As described in detail above, according to the damping force adjusting type hydraulic shock absorber of the present invention, when the main oil liquid passage is opened and the bypass passage is closed by the damping force adjusting valve, the valve characteristic of the main disk valve is improved. When a damping force is generated and the main oil liquid passage is closed and the bypass passage is opened, a damping force of the valve characteristic due to the sub-disk valve is generated, and when both the main oil liquid passage and the bypass passage are opened, the main disc valve and the sub-disc valve combine. The damping force of the characteristic valve characteristic is generated. As a result, the damping force characteristics are hard, medium and soft.
The valve characteristics can be changed as follows. Also, at this time, at the time of the hard characteristic and the soft characteristic, since the oil liquid flows through only one of the main oil liquid passage and the bypass passage, the damping force characteristics on the hard side and the soft side do not affect each other, so the damping force It has an excellent effect that the degree of freedom in setting the characteristics is increased.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of the present invention.

2 is a perspective view of a check valve of the apparatus of FIG.

3 is a diagram showing the rotational position of the shutter of the apparatus shown in FIG. 1, showing the shutter, piston rod, and partition member along the lines A ₁ -A ₁ and B ₁ -B ₁ in FIG. 4, and the line A ₂ -A _{2 in} FIG. B ₂ -B ₂ line, in FIG. 6
A ₃ is a transverse sectional view -A _3-wire and B ₃ -B ₃ line.

FIG. 4 is a vertical cross-sectional view of an essential part showing a state in which the damping force characteristic of the device of FIG. 1 is switched to a hard characteristic.

5 is a vertical cross-sectional view of a main part showing a state in which the damping force characteristic of the device of FIG. 1 is switched to a medium characteristic.

FIG. 6 is a vertical cross-sectional view of an essential part showing a state in which the damping force characteristic of the device of FIG. 1 is switched to the soft characteristic.

FIG. 7 is a vertical cross-sectional view of a main part of a conventional damping force adjusting hydraulic shock absorber.

[Explanation of symbols]

 13 Damping force adjustable hydraulic shock absorber 14 Cylinder 14a Cylinder upper chamber 14b Cylinder lower chamber 15 Piston 15a, 15b chamber (main oil liquid passage) 16 Piston rod 25 Compression side communication passage (main oil liquid passage) 26 Extension side communication passage ( Main oil liquid passage) 27,31 Main disk valve 29 Expansion side communication passage (main oil liquid passage) 30 Compression side communication passage (main oil liquid passage) 33,34 Oil liquid passage (main oil liquid passage) 35,36 ports ( Main oil liquid passage) 37 Bypass passage 42,43 Sub disk valve 45 Shutter (damping force adjustment valve) 51 Communication groove (main oil liquid passage)

Claims (1)

[Claims] 1. A cylinder in which oil liquid is sealed, a piston fitted in the cylinder to define two chambers in the cylinder, one end of which is connected to the piston and the other end of which extends to the outside of the cylinder. An extended piston rod, a main oil liquid passage that connects the two chambers of the cylinder, a main disk valve that controls the flow of the oil liquid in the main oil liquid passage to generate a damping force, and A bypass passage that connects the two chambers, a sub-disk valve that controls the flow of the oil liquid in the bypass passage to generate a damping force, and a damping force adjusting valve that selectively opens and closes the main oil passage and the bypass passage, respectively. A damping force adjusting hydraulic shock absorber, characterized by comprising: