JP3312289B2 - 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-adjustable hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art A hydraulic shock absorber mounted on a suspension system of a vehicle such as an automobile is provided with a damping force that can be appropriately adjusted according to road surface conditions, running conditions, and the like in order to improve ride comfort and steering stability. There is a damping force adjustable hydraulic shock absorber.

[0003] In this type of hydraulic shock absorber, generally, a piston rod penetrates into a cylinder filled with an oil liquid, and a connected piston is slidably fitted therein to define the inside of the cylinder into two chambers. A damping force generating mechanism such as a disk valve, an orifice, etc., for generating a damping force by controlling a flow of the oil in the main oil passage and a main oil liquid passage for communicating the two chambers in the cylinder with the piston; 2 in the cylinder
A bypass passage for communicating the chamber and a damping force adjusting valve for adjusting a passage area of the bypass passage are provided.

With this configuration, when the damping force adjusting valve is opened, the oil in the cylinder mainly flows through the bypass passage and the damping force on both the extension side and the contraction side is small due to the sliding of the piston accompanying the expansion and contraction of the piston rod. Is generated, and the damping force characteristic becomes a soft characteristic. In addition, when the damping force adjustment valve is closed, the oil in the cylinder flows only through the main oil liquid passage and generates a large damping force on both the expansion and contraction sides due to the sliding of the piston accompanying the expansion and contraction of the piston rod. The force characteristics are hard characteristics. Thus, the damping force characteristics can be switched by opening and closing the damping force adjusting valve.

However, in such a damping force adjusting type hydraulic shock absorber, since the damping force characteristic is adjusted by changing the passage area of the bypass passage, that is, the orifice area of the oil liquid passage, the adjustment range of the damping force characteristic is limited. Orifice characteristics (characteristics in which the damping force increases quadratically in proportion to the piston speed) have been limited. For this reason, even if the adjustment range of the passage area of the bypass passage by the damping force adjustment valve is increased, the adjustment range of the damping force characteristic is limited, and an appropriate damping force characteristic for achieving both riding comfort and steering stability is provided. It was difficult to obtain.

Therefore, conventionally, a sub-valve mechanism having a disk valve for controlling the flow of the oil liquid in the bypass passage is provided at the tip of the piston rod penetrated by the piston,
There has been proposed a device in which valve characteristics (a characteristic in which the damping force increases linearly in proportion to the piston speed) can be adjusted by opening and closing the damping force adjusting valve.

[0007]

However, in a conventional damping force adjusting type hydraulic shock absorber provided with a sub-valve mechanism,
Since the sub-valve mechanism is provided at the tip of the piston rod penetrated by the piston, there is a problem that the overall length of the piston part is long and the expansion and contraction stroke of the piston rod is short. Also, in order to be able to adjust both the valve characteristics and the orifice characteristics, it is necessary to separately provide a bypass passage for adjusting the orifice characteristics and a damping force adjusting valve, which causes a problem that the structure becomes very complicated. is there.

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 which can adjust both the orifice characteristics and the valve characteristics and has a simple structure. And

[0009]

In order to solve the above problems, a cylinder filled with an oil liquid and a piston slidably fitted in the cylinder and defining the inside of the cylinder as two chambers are provided. A piston rod having one end connected to the piston and the other end extended to the outside of the cylinder, a communication passage provided in the piston for communicating two chambers in the cylinder, and a flow of the oil liquid in the communication passage. A valve valve for controlling the pressure control valve to generate a damping force, a valve characteristic adjusting valve for adjusting the passage area of the communication passage, a bypass passage provided along the piston rod and communicating the two chambers in the cylinder, An orifice characteristic adjusting valve for adjusting a passage area of the bypass passage; and an orifice characteristic adjusting valve connected to the valve characteristic adjusting valve and the orifice characteristic adjusting valve, inserted into the piston rod and extended to the outside. Characterized by comprising an operating rod.

[0010]

According to this structure, when the valve characteristic adjusting valve and the orifice characteristic adjusting valve are externally operated via the operating rod, the passage area of the communication passage is changed by the valve characteristic adjusting valve, and the valve characteristic is adjusted. The orifice characteristic is adjusted by changing the passage area of the bypass passage by the characteristic adjustment valve.

[0011]

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

As shown in FIG. 1, in a damping force adjusting type hydraulic shock absorber 1, a piston 3 is slidably fitted in a cylinder 2 in which an oil liquid is sealed. Are defined in two chambers, a cylinder upper chamber 2a and a cylinder lower chamber 2b. One end of a piston rod 4 is connected to the piston 3, and the other end of the piston rod 4 is inserted through a rod guide (not shown) and a seal member (not shown) attached to the upper end of the cylinder 2. It has been extended to the outside. The cylinder 2 is connected to a reservoir (not shown) in which oil and gas are sealed, and changes in volume in the cylinder 2 due to the stroke of the piston rod 4 due to compression and expansion of the gas in the reservoir. It is designed to compensate.

The piston 3 has an annular piston member 5 and a piston member 6 joined to each other, and disc valves 7, 8 (described later) are overlapped on both ends thereof, and a substantially cylindrical piston bolt 9 is inserted through these. The nut 10 is integrally formed by screwing the nut 10 to the tip. A cylindrical portion 4a formed at one end of the piston rod 4 is screwed to a screw portion 9a formed at the base end of the piston bolt 9.

As shown in FIG. 4, in the piston members 5 and 6, a substantially fan-shaped extending shutter chamber 11 and a contracting shutter chamber 12 are formed in the joint portion by concave portions formed on end faces facing each other. . The piston member 5 has a plurality (five in the illustrated example) of ports 13a to 13e that penetrate in the axial direction and communicate with the extension-side shutter chamber 11, and a plurality of ports (shown in the illustration) that communicate with the contraction-side shutter chamber 12. Then 5
Ports 14a to 14e are juxtaposed along the circumferential direction, the ports 13a to 13e form the extension side communication path 13, and the ports 14a to 14e form the contraction side communication path 14. Similarly, the piston member 6 has ports 15a to 15e (only one is shown in FIG. 1) communicating with the extension-side shutter chamber 11 and a port 16a communicating with the contraction-side shutter chamber 12.
~ 16e (only one is shown in Figure 1)
The ports 15a to 15e form the extension side communication path 15, and the ports 16a to 16e form the contraction side communication path 16.

The ports 13a to 13e and the ports 15a to
15e, the openings are arranged to face each other and communicate with each other via the extension-side shutter chamber 11, whereby the cylinder upper chamber 2a and the cylinder lower chamber 2b communicate with each other. Similarly, the ports 14a to 14e and the ports 16a to 16e communicate with each other via the contraction shutter chamber 12, and the upper cylinder chamber 2a and the lower cylinder chamber 2b communicate with each other.

The openings of the ports 15a to 15e on the cylinder lower chamber 2b side are provided so as to face the disk valve 7. The disk valves 7 allow the ports 13a to 13e and the ports 15a to 15e to be opened from the cylinder upper chamber 2a side. Cylinder lower chamber
The damping force is generated by controlling the flow of the oil liquid to the side 2b, and the flow of the oil liquid in the opposite direction is prevented. The openings of the ports 16a to 16e on the cylinder upper chamber 2a side are:
The ports 14a to 14e and the ports 16a are provided so as to face the disc valve 8.
The damping force is generated by controlling the flow of the oil liquid from the cylinder lower chamber 2b side to the cylinder upper chamber 2b side, thereby preventing the flow of the oil liquid in the opposite direction. In the above description, each of the ports 13, 14, 15, and
Sixteen ports a to e are provided, respectively.
Only ports a to e are provided, and ports 13 and 16 are 13a and 16a
May be one port as a large-diameter port.

A shutter plate 17 is rotatably fitted to the joint of the piston members 5 and 6 as a valve characteristic adjusting valve. The shutter plate 17 is an extension-side shutter chamber.
A fan-shaped extension-side shutter portion 17a movable along 11;
A fan-shaped contraction-side shutter portion 17b movable along the contraction-side shutter chamber 12, and a connecting portion 17c for connecting these to each other
By rotating, the extension side shutter part
17a communicates with ports 13a to 13e and ports 15a to 15e,
In addition to shutting off, the port 14a is
14e and the ports 16a to 16e are communicated and blocked. As shown in FIGS. 2 and 3, a groove 18 is provided in the side wall of the piston bolt 9 to allow the rotation of the shutter plate 17 by inserting the connecting portion 17c. After that, a spacer 19 (see FIG. 2) is fitted into the groove portion 18, and the nut 10 is screwed.

The communication passages 13a and 15a and the communication passages
There is always communication between 14a and 16a, and the shutter plate
When 17 is in the rotational position shown by the imaginary line in FIG. 4, when the ports 13b to 13e, 15b to 15e and the ports 14b to 14e,
16b to 16e are shut off, and by rotating the shutter plate 17 to one side from this position, the ports 13b to 13e, 1
The communication passages 5b to 15e and the ports 14b to 14e and 16b to 16e are sequentially communicated so that the extension communication passages 13, 15 and the contraction communication passage are provided.
The communication passage areas 14 and 16 can be adjusted in five steps according to the rotation angle.

A passage 20 is provided on the side wall of the cylindrical portion 4a of the piston rod 4, and the passage 20, the inside of the cylindrical portion 4a and the passage 21 in the piston bolt 9 extend along the piston rod 4. A bypass passage that connects the cylinder upper chamber 2a and the cylinder lower chamber 2b is formed. An orifice characteristic adjusting valve 22 for adjusting the passage area of the bypass passage is provided inside the cylindrical portion 4a.

The orifice characteristic adjusting valve 22 has a bottomed cylindrical shutter 24 rotatably fitted in a bottomed cylindrical guide member 23. The guide member 23 is inserted into the cylindrical portion 4a of the piston rod 4 with a gap, and is fixed in contact with a retainer 25 interposed between the guide member 23 and the base end of the piston bolt 9. The inside is piston bolt 9
The passage 21 is communicated with.

The side wall of the guide member 23 is provided with a telescopic port 26 at the lower part and a contraction port 27 at the upper part. As shown in FIG. 5, the expansion / contraction-side ports 26 are a plurality of ports (five sets arranged two at 180 ° different positions in the figure) arranged side by side in the circumferential direction and having different diameters.
26a to 26e, and the ports 26a, 26b, 26
The diameter becomes larger in the order of c, 26d, and 26e. Similarly, the contraction side port 27 is, as shown in FIG.
a to 27e, and ports 27a, 27b, 27c
, 27d, and 27e in this order. Further, the contraction side port 27 is provided with a check valve 28 that allows only the flow of the oil liquid from the inside to the outside of the guide member 23.

A slit 29 is provided on the side wall of the shutter 24 so as to face one set of each of the expansion / contraction port 26 and the extension port 27. Then, the shutter 24 is rotated, and the slit 29 is moved to the telescopic side port 26 (ports 26a to 26e).
By selectively matching each of the contraction-side ports 27 (ports 27a to 27e) with a set of ports, the communication area of the bypass passage is adjusted. in this case,
When the shutter 24 is in the rotation position shown in FIGS. 5 and 6, the slit 29 communicates with the ports 26a and 27a having the minimum diameters to minimize the passage area of the bypass passage. Port 29 sequentially
The passage area is gradually increased by matching with the ports 26b to 26e and the ports 27b to 27e, so that the passage area can be adjusted in five stages according to the rotation angle.

At the bottom of the guide member 23, a latch ball 30 and a spring 31 are provided.
Is engaged with a concave portion 32 provided at the bottom of the shutter 24, so that the shutter 24 can be held at a predetermined position where the slit 29 is aligned with a set of ports of the telescopic side port 26 and the contraction side port 27. ing.

One end of an operating rod 33 is connected to the bottom of the shutter 24, and the other end of the operating rod 33 is inserted through the bottom of the guide member 23 and the piston rod 4 and extends to the outside. In addition, a connecting member is provided in the opening of the shutter 24.
One end of a connecting rod 35 is connected via 34, the connecting rod 35 is inserted into the passage 21 of the piston bolt 9, and a cylindrical shutter holder 36 is connected to the other end. The shutter holder 36 is rotatably fitted in the passage 21, and a connecting portion 17 c of the shutter plate 17 is fitted in a groove 37 provided in a side wall.
Are engaged.

As described above, the operating rod 33 is
Is connected directly to the shutter plate 17 via a connecting rod 35, and is externally connected to the operating rod 33.
By rotating the shutter 24, the shutter 24 is rotated, and the connecting rod 35, the shutter holder 36, and the shutter plate 17 are rotated in conjunction with the rotation of the shutter 24. At this time,
The shutter 24 and the shutter plate 17 are connected to the slits 29 of the shutter 24 in order to sequentially align with the ports 26a to 26e and the ports 27a to 27e, and the extension side shutter portion 17a and the contraction side shutter portion 17b are connected to the ports 13a to 13e. , 15a to 15
e and ports 14a to 14e and ports 16a to 16e are connected by a connecting rod 35 at a rotation angle such that the communication paths are sequentially performed.

The operation of the embodiment constructed as described above will now be described.

During the extension stroke of the piston rod 4,
When the piston speed is in a low speed range, the oil liquid in the cylinder upper chamber 2a flows into the bypass passage, that is, the passage 20 of the piston rod 4, the orifice characteristic adjusting valve 22, and the piston bolt 9
Through the passage 21 to the cylinder lower chamber 2b side, and a damping force is generated by the orifice characteristic adjusting valve 22. At this time, in the orifice characteristic adjusting valve 22, the check valve 28 closes the contraction side communication passage 27, and the oil liquid flows through the expansion / contraction side port 26, so that a damping force of the orifice characteristic is generated according to the passage area. . By operating the operating rod 33 to rotate the shutter 24 to selectively communicate one set of the ports 26a to 26e, the orifice characteristics can be adjusted in five stages.

Also, when the piston speed is in the middle and high speed range,
The pressure of the oil liquid in the cylinder upper chamber 2a reaches a predetermined pressure, the disc valve 7 opens and flows to the cylinder lower chamber 2b through the extension side communication passages 13 and 15 to generate a damping force of valve characteristics. I do. At this time, the shutter plate 17 is rotated together with the shutter 24, and the ports 13a to 13e and the ports 15a to 1
By changing the number of communication passages (passage area) with 5e, the inclination of valve characteristics can be adjusted in five stages.

During the contraction stroke of the piston rod 4,
When the piston speed is in the low speed range, the oil liquid in the cylinder lower chamber 2b passes through the bypass passage, that is, the passage 2 of the piston bolt 9.
1. Flow through the orifice characteristic adjusting valve 22 and the passage 20 of the piston rod 4 to the cylinder upper chamber 2a side, and the orifice characteristic adjusting valve 22 generates a damping force. At this time, in the orifice characteristic adjusting valve 22, the check valve 28 opens the contraction side communication passage 27, and the oil liquid flows through the expansion / contraction side port 26 and the contraction side port 27, so that the orifice characteristic is adjusted according to the passage area. A damping force is generated. Then, by operating the operation rod 33 to rotate the shutter 24, the ports 26a to 26e and the ports
By selectively communicating one set of 27a to 27e, the orifice characteristics can be adjusted in five steps. In addition,
As the passage area increases due to the communication of the contraction side port 27,
A smaller damping force is generated at the same piston speed than during the extension stroke.

When the piston speed is in the middle and high speed range,
When the pressure of the oil liquid in the lower cylinder chamber 2b reaches a predetermined pressure, the disc valve 8 opens and flows to the upper cylinder chamber 2a through the contraction side communication passages 14 and 16, thereby generating damping force of valve characteristics. I do. At this time, the shutter plate 17 is rotated together with the shutter 24, and the ports 14a to 14e and the ports 16a to 1
By changing the number of passages (passage area) with 6e, the inclination of the valve characteristics can be adjusted in five stages.

Next, the damping force characteristics of the damping force adjusting type hydraulic shock absorber 1 will be described with reference to FIG. When the rotational positions of the shutter 24 and the shutter plate 17 are in the positions shown in FIGS. 4 to 6, the ports 26a and 27a having the minimum diameter of the orifice characteristic adjusting valve 22 are opened, and the extension side connection provided in the piston portion is opened. Only the area between the ports 13a and 15a of the passages 13 and 15 and between the ports 14a and 16a of the compression side communication paths 14 and 16 are minimized, and the area of the communication path is minimized. The damping force characteristics (orifice characteristics and valve characteristics) are as shown in FIG. It is maximum as shown. When the shutter 24 and the shutter plate 17 are rotated to one side from this position, the orifice characteristic adjusting valve
22 sequentially, large-diameter ports 26b to 26e and port 27b
27e are selectively communicated with each other, and in conjunction with this, the ports 13b-13e, 15b
Between ports 13a and ports 14b to 14e of contraction side communication paths 14, 16;
The number of communication passages between 16b to 16e increases sequentially, the communication passage area increases, and the damping force characteristics (orifice characteristics and valve characteristics) gradually decrease as shown in FIG. The valve characteristics are as follows: the expansion-side communication passages 13 and 15 and the contraction-side communication passage 1
The valve opening pressures of the disc valves 7, 8 hardly change because they are adjusted by the passage areas 4 and 16, ie, the passage areas when the disc valves 7, 8 are opened.

By operating the operating rod 33 to rotate the shutter 24 and the shutter plate 17 in this manner, the orifice characteristic adjusting valve 22 of the piston rod 4 is rotated.
The passage area of the (bypass passage) and the passage areas of the extension-side communication passages 13 and 15 and the contraction-side communication passages 14 and 16 of the piston 3 are simultaneously adjusted to simultaneously show both the orifice characteristic and the valve characteristic in FIG. Can be adjusted in five stages. As a result, the adjustment range of the damping force characteristics is widened, and the damping force characteristics suitable for improving the riding comfort and the steering stability of the vehicle can be obtained.

Further, the passage area of the communication passage provided in the piston 3 is adjusted by the shutter plate 17, and the passage area of the bypass passage provided in the piston rod 4 is adjusted by the orifice characteristic adjusting valve 22. The structure is simple and the stroke of the piston rod 4 is not restricted.

In this embodiment, the damping forces on the extension side and the contraction side are adjusted to have the same tendency (hard or soft on both the expansion and contraction sides).
By changing the port arrangement of the communication passages 14 and 16 on the contraction side and the port arrangement of the expansion / contraction port 26 and the contraction side port 27 of the orifice characteristic adjusting valve 22, damping force characteristics different in size between the extension side and the contraction side are obtained. A combination (elongation side hardware, contraction side software or extension side software, combination of compression side hardware, etc.) can be set.

In this embodiment, the extension-side communication passages 13, 1
5. Compression side communication passages 14, 16 and orifice characteristic adjustment valve 22
By sequentially switching the communication and opening and closing of the ports, the damping force characteristic is adjusted stepwise,
The damping force characteristics can be continuously changed by gradually changing the port area with the shutter 24 and the shutter plate 17.

[0036]

As described in detail above, the damping force-adjusting hydraulic shock absorber of the present invention is provided along a piston rod and a valve characteristic adjusting valve for adjusting a passage area of a communication passage provided in a piston. An orifice characteristic adjustment valve for adjusting the passage area of the bypass passage is provided, and an operation rod inserted into the piston rod and extended to the outside is connected to these valves. When the valve characteristic adjusting valve and the orifice characteristic adjusting valve are operated, the passage area of the communication passage is changed by the valve characteristic adjusting valve to adjust the valve characteristic, and at the same time, the passage area of the bypass passage is changed by the orifice characteristic adjusting valve. The orifice characteristics are adjusted. As a result, both the orifice characteristic and the valve characteristic can be adjusted at the same time, so that the adjustment range of the damping force characteristic is widened, and it is possible to obtain the damping force characteristic suitable for improving the riding comfort and steering stability of the vehicle. It has excellent effects. Further, the structure is simple, and there is no restriction on the stroke of the piston rod.

[Brief description of the drawings]

FIG. 1 is a side longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is an exploded perspective view of a piston bolt, a shutter plate, a shutter holder, a connecting rod, and a spacer of the apparatus of FIG.

FIG. 3 is a side view of a piston bolt of the device of FIG. 1;

FIG. 4 is an arrow view of the piston member taken along line AA of FIG. 1;

FIG. 5 is a cross-sectional view of the guide member and the shutter taken along line BB in FIG. 1;

FIG. 6 is a cross-sectional view of the guide member and the shutter taken along line CC of FIG. 1;

FIG. 7 is a diagram showing damping force characteristics of the device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Damping force adjustment type hydraulic shock absorber 2 Cylinder 2a Upper cylinder chamber 2b Lower cylinder chamber 3 Piston 4 Piston rod 7,8 Disc valve 13,15 Extension communication path (communication path) 14,16 Contraction communication path (communication path) 17 Shutter plate (valve characteristic adjustment valve) 20,21 Passage (bypass passage) 22 Orifice characteristic adjustment valve 33 Operation rod 35 Connecting rod (operation rod)

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

Claims (1)

(57) [Claims] 1. A cylinder filled with an oil, a piston slidably fitted in the cylinder and defining two chambers in the cylinder, and one end connected to the piston and the other end connected to the cylinder. A piston rod extended to the outside of the
A communication passage provided in the piston for communicating two chambers in the cylinder, a disk valve for controlling the flow of oil in the communication passage to generate a damping force, and a valve characteristic for adjusting a passage area of the communication passage A regulating valve, a bypass passage provided along the piston rod and communicating the two chambers in the cylinder, an orifice characteristic regulating valve for regulating the passage area of the bypass passage, the valve characteristic regulating valve and the orifice characteristic regulating valve And an operating rod inserted into the piston rod and extended to the outside.