JPH0754901A - Hydraulic shock absorber with adjustable damping force - Google Patents

Abstract

PURPOSE:To widen the adjusting range of the damping force characteristics by forming at least either of the elongation side and the contraction side damping force adjusting mechanism from a back pressure chamber, which energizes a disc valve in the direction of valve closing, and a shutter mechanism which adjusts the area of a downstream communication path. CONSTITUTION:When a piston rod 4 is in the elongation stroke, the oil in the cylinder up-chamber 2a is pressurized in association with sliding of a piston 3 and passed through the elongation side passage B1 to flow to the cylinder down-chamber 2b. If the piston speed at this time is low and before a disc valve 7 is opened, a damping force according to the orifice characteristics is generated in compliance with the area of communication path leading from a port 23 to an opening 27 of a shutter 26. When the speed of the piston 3 increases, the pressure in the cylinder up-chamber 2a rises to open the disc valve 7, and a damping force according to the valve characteristics is generated. Therefore, it is practicable to adjust the damping force characteristics by rotating the shutter 26. During the contraction stroke, on the contrary, the oil in the cylinder down-chamber 2b passes through the contraction side passage B2 to flow to the cylinder up-chamber 2a.

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 In a hydraulic shock absorber mounted on 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 damping force adjustable hydraulic shock absorber.

In this type of hydraulic shock absorber, a piston, to which a piston rod is connected, is slidably fitted in a cylinder in which an oil liquid is sealed, and two chambers in the cylinder are defined by the piston. Is connected to the main oil liquid passage and the bypass passage, and a damping force generating mechanism (orifice, disk valve, etc.) for generating a large damping force is provided in the main oil liquid passage,
The bypass passage is provided with a damping force generation mechanism that generates a small damping force and a damping force control valve that opens and closes the bypass passage.

With this configuration, when the damping force adjusting valve is opened, the oil liquid in the cylinder mainly flows through the bypass passage due to the sliding of the piston due to the expansion and contraction of the piston rod, and the small damping force is applied to both the expansion side and the compression side. Occurs, and the damping force characteristic becomes a soft characteristic. On the other hand, when the damping force adjusting valve is closed, the oil liquid in the cylinder flows only through the main oil liquid passage to generate a large damping force on both the expansion side and the contraction side, and the damping force characteristic becomes a hard characteristic. In this way, the damping force characteristic can be switched by opening and closing the damping force adjusting valve.

During normal running of the vehicle, by selecting the damping force characteristic on the soft side, the vibration due to the unevenness of the road surface can be absorbed to improve the riding comfort, and also during turning, acceleration and braking. At the time of running and at high speeds, by selecting the damping force characteristics on the hard side, it is possible to suppress changes in the posture of the vehicle body and improve steering stability. Furthermore, by combining a damping force adjusting hydraulic shock absorber with a control device and an actuator, the damping force is automatically switched in real time according to road conditions, running conditions, etc. to improve riding comfort and steering stability. There is a suspension control device.

As described above, in order to appropriately adjust the damping force in response to various situations, it is required to widen the adjustment range of the damping force characteristic of the hydraulic shock absorber. However, in the case where the passage area of the bypass passage is adjusted by the damping force adjusting valve as described above, the damping force characteristic is adjusted only by changing the orifice characteristic when the bypass passage is opened, that is, when the soft characteristic is set. The adjustment range of damping force characteristics is narrowed. Therefore, conventionally, Japanese Patent Laid-Open No. 58-7794
As described in Japanese Patent Publication No. 3, the pressure of the cylinder chamber is introduced into the pressure chamber formed on the back side of the disc valve that is the damping force generation mechanism of the main oil liquid passage, and the disc valve is driven by the spool that responds to this pressure. A damping force adjustable hydraulic shock absorber has been proposed in which the damping force characteristic adjustment range is widened by changing the initial valve opening pressure of the disc valve in addition to the orifice characteristic by urging the valve closing direction. There is.

[0007]

However, even if the initial valve opening pressure of the disc valve can be adjusted in addition to the above-mentioned conventional orifice characteristic, an appropriate damping force characteristic can be obtained depending on the driving condition of the vehicle. Not necessarily.

The present invention has been made in view of the above points, and a damping force adjusting hydraulic pressure that widens the adjustment range of the damping force characteristic and obtains an appropriate damping force characteristic corresponding to a wide range of operating conditions. The purpose is to provide a shock absorber.

[0009]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a cylinder in which an oil liquid is sealed, and two chambers inside the cylinder that are slidably fitted in the cylinder. And a piston rod, one end of which is connected to the piston and the other end of which extends to the outside of the cylinder, and two chambers in the cylinder are communicated with each other so that the oil liquid during the extension stroke of the piston rod Adjusting the passage area of the extension side passage, which allows only the flow, and the contraction side passage, which allows the two chambers in the cylinder to communicate with each other and allows only the flow of the oil liquid during the compression stroke of the piston rod, and the extension side passage. A damping force adjustable hydraulic shock absorber comprising an extension side damping force adjusting mechanism and a contraction side damping force adjusting mechanism for adjusting the passage area of the contraction side passage, wherein the extension side damping force adjusting mechanism and the contraction side damping force adjustment are provided. At least of mechanism One is a disc valve, a back pressure chamber provided on the back side of the disc valve for urging the disc valve in the valve closing direction by an internal pressure, and the back pressure chamber and the upstream chamber in the cylinder are communicated with each other. An upstream communication passage, a downstream communication passage that communicates the back pressure chamber with a downstream chamber in the cylinder, and a shutter mechanism that adjusts a passage area of the downstream communication passage. Characterize.

A damping force adjusting hydraulic shock absorber according to a second aspect of the present invention is a cylinder in which an oil liquid is sealed, and a piston that is slidably fitted in the cylinder and defines the inside of the cylinder into two chambers. And a piston rod, one end of which is connected to the piston and the other end of which extends to the outside of the cylinder, and an extension which allows two chambers in the cylinder to communicate with each other and allows the oil liquid to flow during the extension stroke of the piston rod. A side passage, a contraction side passage that allows the two chambers in the cylinder to communicate with each other and allows the oil liquid to flow during the compression stroke of the piston rod, and at least one of the extension side passage or the contraction side passage, A disc valve that controls the flow of the oil liquid in the one passage to generate a damping force, a back pressure chamber that is provided on the back side of the disc valve and biases the disc valve in the valve closing direction by an internal pressure, Back pressure And an upstream communication passage that communicates with an upstream chamber in the cylinder, a downstream communication passage that communicates the back pressure chamber with a downstream chamber in the cylinder, and a passage area of the downstream communication passage. A first shutter mechanism for adjusting
And a second shutter mechanism which is provided on the downstream side of the disc valve in the one passage provided with the disc valve and which adjusts the passage area of the one passage.

In addition to the damping force adjusting hydraulic shock absorber of the third invention, in addition to that of the first invention, the disk of at least one of the expansion side passage and the contraction side passage provided with a disc valve is provided. A second shutter mechanism for adjusting the passage area of the one passage is provided on the downstream side of the valve.

[0012]

With this configuration, according to the first aspect of the present invention, the extension side damping force adjusting mechanism adjusts the damping force of the piston rod during the extension stroke, and the contraction side damping force adjusting mechanism adjusts the piston rod contraction. Since the damping force during the stroke is adjusted, different types of damping force characteristics can be set on the extension side and the contraction side. Also, since the back pressure chamber is pressurized according to the pressure loss due to the passage area of the shutter mechanism as the piston rod strokes, reducing the passage area of the shutter mechanism increases the pressure in the back pressure chamber and opens the disc valve. When the valve pressure increases and the passage area of the shutter mechanism increases, the pressure in the back pressure chamber decreases and the valve opening pressure of the disk valve decreases, so the valve opening pressure of the disk valve can be adjusted.

According to the second aspect of the invention, the back pressure chamber is pressurized according to the pressure loss due to the passage area of the first shutter mechanism with the stroke of the piston rod. When the area is reduced, the pressure in the back pressure chamber rises and the valve opening pressure of the disc valve increases, and when the passage area of the first shutter mechanism is increased, the pressure in the back pressure chamber decreases and the valve opening pressure of the disc valve increases. Since it becomes low, the valve opening pressure of the disc valve can be adjusted. Further, by adjusting the passage area of the second shutter, it is possible to adjust the valve characteristic after the disc valve is opened.

According to the third invention, the extension side damping force adjusting mechanism adjusts the damping force during the extension stroke of the piston rod, and the compression side damping force adjusting mechanism adjusts the damping force during the compression stroke of the piston rod. Since the adjustment is performed, different types of damping force characteristics can be set on the extension side and the contraction side.
Also, since the back pressure chamber is pressurized according to the pressure loss due to the passage area of the shutter mechanism as the piston rod strokes, reducing the passage area of the shutter mechanism increases the pressure in the back pressure chamber and opens the disc valve. When the valve pressure increases and the passage area of the shutter mechanism increases, the pressure in the back pressure chamber decreases and the valve opening pressure of the disk valve decreases, so the valve opening pressure of the disk valve can be adjusted. Further, by adjusting the passage area of the second shutter mechanism, it is possible to adjust the valve characteristic after the disc valve is opened.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

The first embodiment will be described with reference to FIG. The right side of FIG. 1 indicates the extension stroke and the left side indicates the contraction stroke.

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. Is divided into two chambers, a cylinder upper chamber 2a and a cylinder lower chamber 2b. One end side of a piston rod 4 penetrates and is connected to the piston 3, and the other end side of the piston rod 4 has a rod guide (not shown) and a seal member (not shown) provided at an end of the cylinder 2. ) And is extended to the outside of the cylinder 2. In addition, the cylinder 2 is provided with a reservoir chamber (not shown) that compensates for the volume change in the cylinder 2 due to the entry and exit of the piston rod 4 by compressing and expanding the gas.

At the end of the piston 3 on the cylinder upper chamber 2a side, a bottomed cylindrical space member 5 is provided at the bottom thereof.
It is provided facing the side. The space member 5 has a piston rod 4 inserted at the bottom thereof, and further has a piston 3
A cylindrical passage member 6 is screwed to the tip of a piston rod 4 which penetrates through and is fixed integrally with the piston 3.

An annular disc valve 7 and a valve member 8 are provided at the opening of the space member 5 so as to overlap each other.
A bottomed cylindrical retainer 10 is provided on the valve member 8 via a spring 9. The retainer 10 is fixed by abutting on a step portion 4a formed on the piston rod 4 penetrating the bottom portion thereof. The disc valve 7 is slidably provided along the side wall of the retainer 10. Further, the valve member 8 is provided slidably along the side walls of the piston rod 4 and the retainer 10, and is urged toward the space member 5 by the elastic force of the spring 9 so that the valve member 8 and the space member 5 are separated from each other. Holds the valve 7 in between.

The valve member 8 is provided with an oil liquid passage 11 which is opened and closed by the disc valve 7.
Reference numeral 11 communicates with the cylinder upper chamber 2a via a notch 12 provided in the side wall of the retainer 10. The disc valve 7 is designed so that the inner peripheral side thereof is bent by the pressure of the oil liquid passage 11, that is, the pressure of the cylinder upper chamber 2a to open the valve to generate a damping force. With respect to the above flow, the spring 9 bends and moves together with the valve member 8 to allow the flow.

Piston rod 4 inside space member 5
A substantially cylindrical defining member 13 is slidably fitted in the. The defining member 13 is biased by a spring 14 so that one end of the defining member 13 is in contact with the back side of the disc valve 7.
The disc valve 7 is provided inside the spacer member 5 by
A passage chamber 15 that communicates with the oil liquid passage 11 via a back pressure chamber 16 located on the back side of the disc valve 7 is defined. The back pressure chamber 16 is communicated with the cylinder upper chamber 2a by a passage 17 provided on the side wall of the space member 5 as an upstream communication passage.

A guide hole 18 is provided in the piston rod 4 along the axis. One end of the guide hole 18 is opened at the tip of the piston rod 4 and communicates with the lower cylinder chamber 2b via the passage member 6, and the other end of the guide hole 18 is the piston rod 4.
Is connected to the passage chamber 13 by a passage 19 provided on the side wall of the. The passage member 8 has a valve member having an oil liquid passage 20 for communicating the guide hole 18 and the cylinder lower chamber 2b.
21 is provided, and the valve member 21 is provided with a check valve 22 which allows only the flow of the oil liquid from the guide hole 18 side of the oil liquid passage 20 to the cylinder lower chamber 2b side.

A guide hole 18 is provided on the side wall of the piston rod 4.
To the back pressure chamber 16 and a pair of ports 23 and a guide hole.
A pair of ports 25 are provided for communicating 18 with the lower cylinder chamber 2b via a passage 24 provided in the piston 3.

A cylindrical shutter 26 is rotatably fitted in the guide hole 18. On the side wall of the shutter 26, a pair of openings 2 are provided so as to face the pair of ports 23 and 25, respectively.
7 and 28 are provided, the port 23 and the opening 27 constitute a downstream side communication passage of the back pressure chamber 16 and the shutter mechanism, and the port 25 and the opening 28 constitute a compression side damping force adjusting mechanism. ing. The openings 27 and 28 extend along the circumferential direction of the shutter 26. The opening 27 is opened in a wedge shape whose diameter increases toward one side, and the opening 28 expands toward the other side. It has a wedge-shaped opening. And shutter
By rotating 26, the area of the communication passage between the port 23 and the opening 27 and the area of the communication passage between the port 25 and the opening 28 are changed.

Here, the relationship between the areas of the communication passages between the ports 23 and 25 and the openings 27 and 28 is that when the area of the communication passages between the ports 23 and 27 is maximum, the communication between the ports 25 and 28 is large. The passage area becomes the minimum, and as the shutter 26 is rotated to one side from this state, the area of the communication passage between the port 23 and the opening 27 decreases, and at the same time, the area of the communication passage between the port 25 and the opening 28 increases, and the port 23 The area of the communication passage between the port 25 and the opening 28 is maximized when the area of the communication path between the port 25 and the opening 27 is minimum.

An operating rod 29 is connected to the shutter 26. The operating rod 29 extends through the piston rod 4 to the outside, and the shutter 29 can be rotated by operating the operating rod 29 from the outside by an actuator or manually.

The piston 3 is provided with a compression-side main oil liquid passage 30 which connects the cylinder upper chamber 2a and the cylinder lower chamber 2b. At the end of the piston 3 on the cylinder upper chamber 2a side, from the cylinder lower chamber 2b side of the compression side main oil passage 30 to the cylinder upper chamber 2a.
A disc valve 31 is provided which allows only the flow of the oil liquid to the 2a side to generate a damping force.

In FIG. 1, 32 is a bush for supporting the shutter 26, 33 is a pin for attaching the check valve 22 to the valve member 21, and 34 is a piston ring.

With the above structure, the valve member 8
Passage 11 and passage chamber 15 and passage 19 for piston rod 4
A guide hole 18, a passage member 6, an oil liquid passage 20 of a valve member 21, a passage 17 of a space member 5, a back pressure chamber 16, a port 23 of a piston rod 4, and an opening 27 of a shutter 23. And constitute an extension side passage B ₁ that connects the cylinder upper chamber 2a and the cylinder lower chamber 2b to each other, and the check valve 22 distributes the oil liquid from the cylinder upper chamber 2a side to the cylinder lower chamber 2b side, that is, Only the oil liquid is allowed to flow during the extension stroke of the piston rod 4.

Further, the passage 24 of the piston 3 and the port 25
The opening 28 of the shutter 26, the guide hole 18, the passage 19 of the piston rod 4, the passage chamber 15, and the contraction side main oil liquid passage 30.
And constitute a compression-side passage B ₂ that connects the cylinder upper chamber 2a and the cylinder lower chamber 2b to each other, and the disc valve 7 and the disc valve 31 act as check valves to allow the cylinder lower chamber 2b side to rise above the cylinder. Circulation of oil liquid to the chamber 2a side,
That is, only the flow of the oil liquid during the compression stroke of the piston rod 4 is allowed.

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

During the extension stroke of the piston rod 4, as the piston 3 slides, the oil liquid in the cylinder upper chamber 2a is pressurized and flows through the extension side passage B ₁ to the cylinder lower chamber 2b. Before the disc valve 7 is opened, the piston speed is low, and a damping force having an orifice characteristic is generated according to the area of the communication passage between the port 23 and the opening 27 of the shutter 26, and the piston speed increases and the cylinder upper chamber 2a increases. When the disc pressure is increased and the disc valve 7 is opened, a damping force having a valve characteristic is generated. Therefore, the damping force characteristic can be adjusted by rotating the shutter 26 and changing the communication passage area between the port 23 and the opening 27.

At this time, the smaller the area of the communication passage between the port 23 and the opening 27, the larger the pressure loss, and the larger the back pressure chamber 15 becomes.
Since the internal pressure of the disk valve 7 increases and the disk valve 7 is biased in the valve closing direction, the valve opening pressure of the disk valve 7 increases. Further, as the area of the communication passage between the port 23 and the opening 27 is increased, the pressure loss is small and the internal pressure of the back pressure chamber 15 is low, so that the opening pressure of the disc valve 7 is low. In this way, by rotating the shutter 26, the orifice characteristic and the opening point of the disc valve 7 can be adjusted.

On the other hand, during the compression stroke of the piston rod 4, as the piston 3 slides, the oil liquid in the cylinder lower chamber 2b is pressurized and flows through the compression side passage B ₂ to the cylinder upper chamber 2a. And the piston speed is small and the disc valve 31
Before the valve is opened, a damping force having an orifice characteristic is generated according to the communication passage area between the port 25 and the opening 28 of the shutter 26, the piston speed increases, the pressure in the cylinder upper chamber 2a rises, and the disc valve 31 When is opened, the oil liquid contracts and flows through the main oil liquid passage 30 to generate a damping force having a valve characteristic. Therefore, the damping force characteristic can be adjusted by rotating the shutter 26 and changing the communication passage area between the port 25 and the opening 28.

When the communication passage area between the port 23 and the opening 27 is maximum, the communication passage area between the port 25 and the opening 28 is minimum, so that the damping force characteristics are soft on the extension side and hard on the contraction side. It becomes a characteristic. From this state, the shutter 26
When is rotated to one side, the communication passage area between the port 23 and the opening 27 is reduced, and the communication passage area between the port 25 and the opening 28 is increased. The damping force becomes smaller. Therefore, the damping force characteristics are medium characteristics on both the extension side and the contraction side. When the shutter 26 is further rotated to one side to maximize the communication passage area between the port 23 and the opening 27, the communication passage area between the port 25 and the opening 28 is maximized, so that the damping force characteristic is hard on the extension side. It becomes a characteristic and the shrink side becomes a soft characteristic.

In this way, different types of damping force characteristics can be set for the extension side and the contraction side, and the shutter 26
The damping force characteristic can be continuously adjusted according to the rotation angle of the. Moreover, since the orifice characteristic and the opening point of the disc valve can be adjusted on the extension side, the adjustment range of the damping force characteristic can be widened.

Next, a second embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 2, in the damping force adjusting type hydraulic shock absorber 35, a piston 37 is slidably fitted in a cylinder 36 in which an oil liquid is sealed. Is the upper chamber 36a of the cylinder and the lower chamber 36b of the cylinder.
It is defined in the room. The piston 37 has a piston rod
One end of 38 penetrates and is connected, and piston rod 38
The other end side thereof is inserted into a rod guide (not shown) and a seal member (not shown) provided at the end of the cylinder 36 and extends to the outside of the cylinder 36. Further, the cylinder 36 is provided with a reservoir chamber (not shown) for compensating the volume change in the cylinder 36 due to the intrusion and retreat of the piston rod 38 by compressing and expanding the gas.

A recess 37a is formed at the end of the piston 37 on the cylinder upper chamber 36a side, a cylindrical retainer 39 is provided in the recess 37a, and an annular spacer 40 described later is provided on the retainer 39. An annular passage member 41 is provided so as to overlap. Further, a recess 37b is formed at the end of the piston 37 on the cylinder lower chamber 36b side, a cylindrical retainer 42 is provided in the recess 37b, and an annular spacer 43 described later is provided on the retainer 42. And tubular passage members 44 are provided in an overlapping manner. Then, the small diameter portion 38a at the tip of the piston rod 38 is inserted through these, and the passage member 44 is inserted into the small diameter portion 38a.
And is fixed to the piston rod 38 integrally with the piston 37.

An annular disc valve 45 is provided at the opening of the recess 37a of the piston 37, and the recess 37a is defined by the cylinder upper chamber 36a. The disc valve 45 is
It is movably fitted over the spacer 40, and its inner peripheral side is bent toward the recess 37a side to open the valve. Here, as shown in FIG. 3, the spacer 40 has a notch 40 on the outer periphery.
a is provided, and the notch 40a forms a passage by bending the inner peripheral side of the disc valve 45. Further, on the outer periphery of the retainer 39, a substantially cylindrical defining member
46 is slidably fitted. The defining member 46 is a spring 47.
The upper end portion is in contact with the back surface side of the disc valve 45, and the inside of the recess 37a is defined by the defining member 46 as a back pressure chamber 46a on the outer peripheral side and a passage chamber 46b on the inner peripheral side. .
The back pressure chamber 46a is provided on the side wall of the piston 37 by means of an oil liquid passage 48 serving as an upstream side communication passage.
It is connected to 36a.

Similarly, an annular disc valve 49 is provided at the opening of the recess 37b of the piston 37, and the recess 37b is defined by the cylinder lower chamber 36b. Disc valve
49 is movably fitted over the spacer 43, and its inner peripheral side is bent toward the recess 37b side to open the valve.
Here, as shown in FIG. 3, the spacer 43 is provided with a cutout portion 43a on its outer circumference, and the cutout portion 43a forms a passage by bending the inner circumferential side of the disc valve 49. A substantially cylindrical defining member 50 is slidably fitted on the outer periphery of the retainer 42. The defining member 50 is urged by a spring 51 so that its upper end is in contact with the back side of the disc valve 49, and the defining member 50 causes the recess 37b to have an outer peripheral side back pressure chamber 50a and an inner peripheral side passage. It is defined as Room 50b. The back pressure chamber 50a is communicated with the lower cylinder chamber 36b by an oil liquid passage 52 provided on the side wall of the piston 37 as an upstream communication passage.

The small diameter portion 38a of the piston rod 38 is provided with a guide hole 53 along its axis. Guide hole 53
Has one end opened at the tip of the small diameter portion 38a and communicating with the cylinder lower chamber 36b, and the other end opened at the side wall of the small diameter portion 38a through an oil liquid passage 54 provided in the passage member 41. It communicates with the cylinder upper chamber 36a. And passage member
A check valve 55 for allowing only the flow of the oil liquid from the oil liquid passage 54, that is, from the inside of the guide hole 53 to the cylinder upper chamber 36a is provided at 41.
And the guide hole 53 is provided in the passage member 44.
A check valve 56 that allows only the flow of the oil liquid from the inside to the cylinder lower chamber 36b is provided.

On the side wall of the small diameter portion 38a of the piston rod 38, a pair of ports 58 communicating with the passage chamber 46b via the passage 57 of the retainer 39, the passage 59 of the retainer 39, and the defining member.
A pair of ports 61 as extension side downstream communication passages communicating with the back pressure chamber 46a through the passages 60 of the 46 and passages of the retainer 42.
A pair of ports 63 communicating with the passage chamber 46b via 62 and a pair of downstream side communicating passages on the compression side communicating with the back pressure chamber 50a via the passage 64 of the retainer 42 and the passage 65 of the defining member 50. Ports 66 and are provided.

A cylindrical shutter 67 is rotatably fitted in the guide hole 53. A pair of openings 68, 69, 70, 71 are provided on the side wall of the shutter 67 so as to face the pair of ports 58, 61, 63, 66, respectively. Openings 68, 6
The reference numerals 9, 70, 71 respectively extend along the circumferential direction of the shutter 67, the openings 68, 69 are formed in a substantially wedge shape whose diameter increases toward one side, and the openings 70, 71 are It is formed in a substantially wedge shape whose diameter increases toward the opposite side. Then, by rotating the shutter 67, the port 58 and the opening 68 that are the first shutter mechanism on the extension side, the port 61 and the opening 69 that are the second shutter mechanism on the extension side,
The second shutter mechanism on the contraction side, which is the port 63 and the opening 70
The area of the communication passage of each of the port 66 and the opening 71, which is the first shutter mechanism on the contraction side, is changed.

Here, the port 58 and the opening 68 and the port
When the communication passage area between 61 and the opening portion 69 is maximum, the communication passage area between the port 63 and the opening portion 70 and between the port 66 and the opening portion 71 becomes the minimum, and as the shutter 67 is rotated to one side from this state, the port 58 and the opening portion are opened. The area of the communication passage between the portion 68 and the port 61 and the opening 69 is reduced, and at the same time, the area of the communication passage between the port 63 and the opening 70 and the communication passage between the port 66 and the opening 71 is increased. When the communication passage between 61 and the opening 69 is minimum, the communication passage between the port 63 and the opening 70 and between the port 66 and the opening 71 is maximum. The communication passage area between the port 58 and the opening 68 is always larger than the communication passage area between the port 61 and the opening 69, and the communication passage area between the port 63 and the opening 70 is equal to the port 66 and the opening 71. The area of the communication passage is always larger.

An operation rod 72 is connected to the shutter 67, and the operation rod 72 is extended along the piston rod 4 to the outside thereof to rotate the shutter 67 from the outside of the damping force adjusting hydraulic shock absorber 35. It is supposed to be done.

In the above configuration, the oil liquid passage 48, the back pressure chamber
46a, passage 60 of defining member 46, passage 59 of retainer 39, port 61, opening 69, passage chamber 46b, passage 57 of retainer 39, port 58, opening 68, inside of shutter 67 and guide hole 53
Is an extension side passage that connects the cylinder upper chamber 36a and the cylinder lower chamber 36b, and the check valve 56 allows only the flow of the oil liquid during the extension stroke of the piston rod 38. . Further, the oil liquid passage 52, the back pressure chamber 50a, the passage 65 of the defining member 50, the passage 64 of the retainer 42, the port 66, the opening 71, the passage chamber 50b, the passage 62 of the retainer 42, the port 63, the opening 70, Inside the shutter 67, the guide hole 53 and the passage member
The oil liquid passage 54 of 41 is provided in the cylinder upper chamber 36a and the cylinder lower chamber 36a.
It forms a contraction side passage that communicates with b.
Therefore, only the flow of the oil liquid during the compression stroke of the piston rod 38 is allowed.

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

During the extension stroke of the piston rod 72, the oil liquid on the cylinder upper chamber 36a side is supplied with the oil liquid passage 48, the back pressure chamber 46a, the passage 60 of the defining member 46, the passage 59 of the retainer 39, the port 61, and the opening. It flows into the shutter 67 through the portion 69. Further, the disc valve 45 is opened to flow into the passage chamber 46b, and then flows into the shutter 67 through the passage 57 of the retainer 39, the port 58, and the opening 68. The oil liquid in the shutter 67 flows from the guide hole 53 to the check valve 56.
To flow into the cylinder lower chamber 36b. Therefore, the piston speed is low and before opening the disc valve 45, the port 61
A damping force having an orifice characteristic is generated according to the area of the communication path of the opening 69. After the piston speed increases and the disc valve 45 opens, a damping force having valve characteristics is generated according to the area of the communication passage between the port 58 and the opening 68.

Therefore, the shutter 67 is rotated to rotate the port 58.
When the area of the communication path between the opening 68 and the port 61 and the opening 69 is increased, a small damping force is generated both before and after the opening of the disc valve 45 (orifice characteristic and valve characteristic).
As the communication passage area is reduced, both the orifice characteristic and the valve characteristic increase in damping force. At this time, the smaller the area of the communication passage between the port 61 and the opening 69, the higher the pressure in the upstream back pressure chamber 46a due to the pressure loss, and the higher the opening pressure of the disc valve 45. Therefore, the damping force characteristic changes as shown in FIG.

On the other hand, during the compression stroke, the oil liquid on the cylinder lower chamber 36b side passes through the oil liquid passage 52, the back pressure chamber 50a, and the passage 6 of the defining member 50.
5, through the passage 64 of the retainer 42, the port 66, and the opening 71 into the shutter 67. Further, the disc valve 49 is opened to flow into the passage chamber 50b, and the passage 62 of the retainer 42 and the port
It flows into the shutter 67 through the opening 70 and the opening 70. Then, the oil liquid in the shutter 67 opens the check valve 55 from the guide hole 53 through the oil liquid passage 54 of the passage member to open the cylinder upper chamber 36a.
Flows to. Therefore, before the disc valve 49 is opened with a low piston speed, a damping force having an orifice characteristic is generated according to the area of the communication passage between the port 63 and the opening 70. Then, after the piston speed increases and the disc valve 49 opens, a damping force having valve characteristics is generated according to the area of the communication passage between the port 63 and the opening 70.

Therefore, the shutter 67 is rotated to rotate the port 63.
When the communication passage area between the opening 70 and the port 66 and the opening 71 is increased, a small damping force is generated both before and after the opening of the disc valve 49 (orifice characteristic and valve characteristic).
As the communication passage area is reduced, both the orifice characteristic and the valve characteristic increase in damping force. At this time, the smaller the area of the communication passage between the port 63 and the opening 70, the higher the pressure in the upstream back pressure chamber 50a due to the pressure loss, and the higher the opening pressure of the disc valve 49. Therefore, the damping force characteristic changes similarly to the extension side shown in FIG.

Then, the port 58, the opening 68, and the port
When the communication passage area between 61 and the opening 69 is maximum, the communication passage area between the port 63 and the opening 70 and between the port 66 and the opening 71 is minimum, so the damping force characteristics are soft on the extension side and hard on the contraction side. Becomes From this state, when the shutter 67 is rotated to one side, the port 58, the opening 68 and the port 61
And the opening 69 have a smaller communication passage area, and the ports 63 and 70 have a larger communication passage area, and the ports 66 and the opening 71 have a larger communication passage area. Therefore, the extension side damping force is large and the contraction side damping force is small. . Therefore, the damping force characteristics are medium characteristics on both the extension side and the contraction side. The shutter 67 is further rotated to one side, and the port 58 and the opening 68 and the port 61 and the opening
When the communication passage area of 69 is maximized, the communication passage areas of the port 63 and the opening 70 and between the port 66 and the opening 71 are maximized, so that the damping force characteristic is the hard characteristic on the extension side and the soft characteristic on the contraction side.

In this way, different types of damping force characteristics can be set on the extension side and the contraction side, and the shutter 67
The damping force characteristic can be continuously adjusted according to the rotation angle of the. At this time, on the extension side, the orifice characteristic and the disk valve 45 are determined by the communication area of the port 58 and the opening 68.
The valve opening pressure is adjusted, and the valve characteristics are adjusted by the communication passage area between the port 61 and the opening 69.
The opening characteristic of the disc valve 49 and the orifice characteristic are adjusted by the area of the communication passage between the port 63 and the opening 71.
By adjusting the valve characteristic with the communication passage area of 70, both the orifice characteristic and the valve characteristic can be adjusted, and the adjustment range of the damping force characteristic can be widened.

[0055]

As described above in detail, in the damping force adjusting hydraulic shock absorber of the present invention, the extension side damping force adjusting mechanism adjusts the damping force during the extension stroke of the piston rod, and the compression side damping force adjusting mechanism. By adjusting the damping force during the compression stroke of the piston rod, different types of damping force characteristics can be set on the extension side and the contraction side. Further, the back pressure chamber is pressurized in accordance with the pressure loss due to the passage area of the first shutter mechanism of the downstream side communication passage due to the stroke of the piston rod, and the disc valve is biased in the valve closing direction. The opening point of the disc valve can be adjusted by the passage area of the mechanism. Further, by providing the second shutter mechanism on the downstream side of the disc valve in the expansion side passage or the contraction side passage, it is possible to adjust the valve characteristic after the disc valve is opened. As a result, different combinations of damping force characteristics can be selected for the extension side and the contraction side, and both the orifice characteristic and the valve characteristic can be adjusted, so the adjustment range of the damping force characteristic can be widened and the vehicle operating conditions can be improved. Correspondingly, an appropriate damping force characteristic can be obtained, and the excellent effect that the riding comfort and the steering stability can be effectively improved is exhibited.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of a main part of a second embodiment of the present invention.

3 is a front view of a spacer of the device of FIG.

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

[Explanation of symbols]

1 Damping force adjusting hydraulic shock absorber 2 Cylinder 2a Cylinder upper chamber 2b Cylinder lower chamber 3 Piston 4 Piston rod 7 Disc valve 16 Back pressure chamber 17 Passage (upstream side communication passage) 23 port (downstream side communication passage, first shutter) Mechanism) 25 ports (shrinkage damping force adjustment mechanism) 27 Opening (first shutter mechanism) 28 Opening (shrinkage damping force adjustment mechanism) B ₁ Expansion side oil liquid passage B ₂ Compression side oil liquid passage 35 Damping force Adjustable hydraulic shock absorber 36 Cylinder 36a Cylinder upper chamber 36b Cylinder lower chamber 37 Piston 38 Piston rod 46a Back pressure chamber 46b Passage chamber (stretch side passage) 48 Oil liquid passage (stretch side passage) 50a Back pressure chamber 50b Passage chamber (shrinkage) Side passage) 52 Oil liquid passage (contraction side passage) 53 Guide hole (expansion side passage, contraction side passage) 54 Oil liquid passage (contraction side passage) 55 Check valve (contraction side passage) 56 Check valve (extension side passage) ) 57 passage (growth side passage) 58 port (second Shutter mechanism) 59 passage (expansion side passage) 60 passage (extension side passage) 61 port (first shutter mechanism) 62 passage (shrink side passage) 63 port (second shutter mechanism) 64 passage (shrink side passage) 65 passage (contraction side passage) 66 port (first shutter mechanism) 67 shutter (extension side passage, contraction side passage) 68 opening (second shutter mechanism) 69 opening (first shutter mechanism) 70 opening (Second shutter mechanism) 71 Opening (first shutter mechanism)

Claims (3)

[Claims] 1. A cylinder in which an oil liquid is sealed, a piston slidably 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 is the cylinder. A piston rod extended to the outside of
An extension side passage that allows the two chambers in the cylinder to communicate with each other and allows only the flow of the oil liquid during the extension stroke of the piston rod;
A compression-side passage that allows the two chambers in the cylinder to communicate with each other and allows only the flow of the oil liquid during the compression stroke of the piston rod;
A damping force adjustable hydraulic shock absorber comprising an extension side damping force adjusting mechanism for adjusting the passage area of the extension side passage and a contraction side damping force adjusting mechanism for adjusting the passage area of the contraction side passage, wherein the extension side At least one of the damping force adjusting mechanism and the compression side damping force adjusting mechanism includes a disc valve, a back pressure chamber that is provided on the back side of the disc valve and biases the disc valve in the valve closing direction by internal pressure, and the back pressure chamber. An upstream communication passage that communicates the chamber with an upstream chamber in the cylinder, a downstream communication passage that communicates the back pressure chamber with a downstream chamber in the cylinder, and a passage of the downstream communication passage A damping force adjusting hydraulic shock absorber, comprising: a shutter mechanism for adjusting an area. 2. A cylinder in which an oil liquid is sealed, a piston slidably 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 is the cylinder. A piston rod extended to the outside of
An extension-side passage that allows the two chambers in the cylinder to communicate with each other and allows the oil liquid to flow during the extension stroke of the piston rod, and the two chambers in the cylinder that communicate with each other to allow the oil liquid to flow during the compression stroke of the piston rod. And a disc valve which is provided in at least one of the expansion side passage and the contraction side passage and which controls the flow of the oil liquid in the one passage to generate a damping force, and the disc valve. A back pressure chamber that is provided on the back side of the cylinder for urging the disk valve in the valve closing direction by the internal pressure, an upstream communication passage that communicates the back pressure chamber with an upstream chamber in the cylinder, and the back pressure. A downstream communication passage that communicates the chamber with a downstream chamber in the cylinder, a first shutter mechanism that adjusts the passage area of the downstream communication passage, and a disc in one of the passages provided with the disc valve. Of valve Damping force adjustable hydraulic shock absorber characterized by comprising a second shutter mechanism for adjusting the passage area of said one passage is provided in the flow side. 3. A second shutter mechanism for adjusting the passage area of the one passage is provided downstream of the disc valve in at least one of the extension side passage and the contraction side passage provided with the disc valve. The damping force adjusting hydraulic shock absorber according to claim 1, wherein.