JPH03223536A - Shock absorber - Google Patents

Abstract

PURPOSE:To controllably regulate a damping force only with a contracting side flow regulating means in a contracting operation by opening a communicating path from an upper chamber to a reservoir chamber with a valve body only in the extending operation of a piston and closing the communicating path in the contracting operation. CONSTITUTION:A check valve 99 in the extending operation of a piston 2 is closed to raise pressure in an upper chamber 3 and open a relief valve 17 for generating a damping force while fluid escapes to a lower chamber 4. Then, the fluid passes through a variable throttle 40 as an extending side flow regulating means. A check valve 22 of a base valve 9 is opened so that the fluid flows from a reservoir chamber 6 to the lower chamber 4. On the other hand, in the contracting operation, the check valve 99 is opened to send the fluid from the lower chamber 4 to an upper chamber 3 so that a relief valve 23 of the base valve 9 is opened to generate the damping force while the fluid in the lower chamber 4 passes through a variable throttle 38 as a contracting side flow regulating means and escapes to the reservoir chamber 6 without passing through the variable throttle 40. Thus, a desirable damping property can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a shock absorber in which damping force on the compression side and damping force on the extension side can be freely adjusted.

Conventional technology As a shock absorber for a vehicle, the inside of the cylinder is divided into an upper chamber and a lower chamber by a piston, and an outer cylinder is provided around the outer circumference of the cylinder, and the space between the cylinder and the outer cylinder is used as a reservoir chamber. A so-called twin tube type is often used.

When the piston is extending, this shock absorber generates damping force by squeezing the passage that communicates the upper and lower chambers with an expansion-side damping force generating valve such as a leaf valve installed on the piston.At the same time, the passage at the lower end of the cylinder is The fluid equivalent to the piston rod that was opened and pulled out of the cylinder flows from the reservoir chamber into the lower chamber, and when the piston retracts, another passage in the piston is opened to allow fluid in the lower chamber to flow into the upper chamber, and at the same time, the cylinder A contraction-side damping force generating valve such as a leaf valve installed at the lower end throttles another passage that communicates the lower chamber and the reservoir chamber, and fluid equivalent to the volume of the piston rod inserted into the cylinder flows from the lower chamber to the reservoir chamber. It is designed to generate a damping force when

In addition, as a conventional shock absorber, a communication passage that communicates between the upper chamber and the reservoir chamber and a communication passage that communicates the lower chamber and the reservoir chamber are provided, and a variable throttle is inserted in these communication passages as a means for adjusting the flow rate. However, by adjusting this variable aperture, the damping force can be freely adjusted and controlled.

This similar structure is shown in, for example, Japanese Utility Model Publication No. 52-6781 and Japanese Utility Model Publication No. 54-4634.

Problems to be Solved by the Invention If a shock absorber can control the damping force completely independently on the extension side and the compression side, it will be possible to obtain more desirable damping characteristics according to needs.

However, if a communication path that communicates the upper chamber and the reservoir chamber and a communication path that communicates the lower chamber and the reservoir chamber are provided, and a variable throttle is simply provided as a flow rate adjustment means in these communication paths, the contraction will occur. At times, fluid passes through both variable restrictors, making it impossible to achieve the precise damping force control desired. In other words, even if the variable aperture on the compression side is set accurately, the damping force on the compression side that actually works varies depending on how the variable aperture on the expansion side is set, so the damping force on the compression side cannot be adjusted and controlled as desired. It disappears.

SUMMARY OF THE INVENTION Therefore, the present invention aims to provide a shock absorber in which the damping force on the extension side and the damping force on the compression side can be adjusted and controlled completely independently, thereby obtaining more desirable damping characteristics according to needs. be.

Means for Solving the Problems The present invention provides, as one means for solving the above-mentioned problems, that the inside of the cylinder is defined by a piston into an upper chamber and a lower chamber, and a reservoir chamber is provided outside the cylinder.
Furthermore, an extension side damping force generating means for generating a damping force when the piston is extending and a contraction side damping force generating means for generating a damping force when the piston is retracting are provided. A check valve that allows fluid to flow from the chamber to the upper chamber is provided, and a check valve that allows fluid to flow from the reservoir chamber to the lower chamber when the piston is extended is provided on the partition member between the lower chamber and the reservoir chamber. In a shock absorber provided with a valve, a communication passage is provided to communicate the lower chamber and the reservoir chamber, and a contraction side flow rate adjusting means is provided in the middle thereof to adjust the flow rate of fluid passing during the contraction operation of the piston. On the other hand, a communication path is provided that communicates the upper chamber and the reservoir chamber, and an extension side flow is provided in the middle of the communication path to adjust the flow rate of fluid passing during the extension operation of the piston. A regulating means and a valve body are provided which allow fluid to flow from the upper chamber to the reservoir chamber only when the pressure in the upper chamber is greater than the pressure in the lower chamber.

2) In addition, as another means, the inside of the cylinder is defined by a piston into an upper chamber and a lower chamber, and a reservoir chamber is provided outside the cylinder, and an extension side damping is provided that generates a damping force when the piston is extended. A force generating means and a compression side damping force generating means for generating a damping force when the piston is retracted are provided, and the piston is provided with a check valve that allows fluid to flow from the lower chamber to the upper chamber during the retracting operation. and a partition member between the lower chamber and the reservoir chamber,
In the Noyock absorber, which is provided with a check valve that allows fluid to flow from the reservoir chamber to the lower chamber during the extension operation of the piston, a communication path is provided that communicates the lower chamber and the reservoir chamber, and the piston A compression-side flow rate adjusting means is provided to adjust the flow rate of fluid passing during the contraction operation of the piston, and a communication path is provided to communicate the upper chamber and the lower chamber, and a communication passage is provided in the middle of the passageway to adjust the flow rate of the fluid passing through the piston during the extension operation. Elongation side flow rate adjustment means was installed to adjust the flow rate through which the flow rate passed.

Effect 1) In the case of the first means, when the piston is extending, the extension-side damping force generating means operates and at the same time, the pressure in the upper chamber increases, so that the fluid in the upper chamber communicates with the reservoir chamber. Pass through the passage and try to escape to the reservoir room. At this time, since the pressure in the upper chamber is greater than the pressure in the lower chamber, the valve body inserted in the middle of the communication passage opens, and the fluid actually passes through this valve body and the expansion side flow rate adjustment means. Exit to the reservoir room. Further, when the piston moves in the extension direction, a check valve provided in the partition member opens, and the liquid in the reservoir chamber passes through the check valve and flows into the lower chamber by the amount that the rod portion of the piston is withdrawn from the cylinder.

On the other hand, when the piston is retracting, the compression-side damping force generation means is activated, and at the same time, the pressure inside the cylinder is increased by the amount that the piston rod enters the cylinder, so the fluid in the cylinder passes through the compression-side flow rate adjustment means. Then exit to the reservoir room. At this time, the check valve installed on the piston opens and the pressure in the upper chamber increases, but the pressure in the upper chamber does not become greater than the pressure in the lower chamber, so the valve body closes the communication passage that communicates the upper chamber and the reservoir chamber. do. Therefore, the fluid does not pass through the extension side flow rate adjustment means.

2) In the case of another means When the piston is extended, the pressure in the upper chamber increases, so the fluid in the upper chamber passes through the extension side flow rate adjustment means and exits to the lower chamber, and at the same time, the check valve installed in the partition member is opened and the rod portion of the piston is removed from the cylinder, allowing the liquid in the reservoir chamber to pass through this check valve and flow into the lower chamber. At this time, the extension side damping force generating means is activated in conjunction with this.

When the piston is retracting, the pressure within the cylinder increases, so the fluid within the cylinder passes through the retraction side flow rate adjusting means and escapes into the reservoir chamber. At this time, the check valve provided on the piston opens and the pressures in the lower chamber and the upper chamber become equal, so that the fluid does not pass through the extension side flow rate adjusting means. In addition, at this time, the compression damping force generating means is activated.

Examples Below, examples corresponding to claim 1 of the present invention will be described.
This will be explained based on FIG.

In FIGS. 1 to 4, 1 is a cylinder, and a piston 2 is housed in the cylinder 1, and the inside thereof is defined into an upper chamber 3 and a lower chamber 4. An outer cylinder 5 is provided on the outer periphery of the cylinder l, and a space between the cylinder 1 and the outer cylinder 5 serves as a reservoir chamber 6. An upper cover member and a bottom member 7 (not shown) are provided at the upper and lower ends of the cylinder l and the outer cylinder 5, respectively, and a piston rod 8 integrally connected to the upper part of the piston 2 is slidably penetrated through the upper cover member. A base valve 9 is interposed between the bottom member 7 and the cylinder l. In this embodiment, the bottom member 7 and the base valve 9 serve as partition members between the lower chamber 4 and the reservoir chamber 6.

The area from the piston 2 to the vicinity of the upper end of the piston rod 8 is formed in a hollow shape, and this hollow portion 10 includes:
The upper end of a communication pipe II that passes through the base valve 9 and whose lower end reaches the bottom member 7 is loosely inserted. A guide cylinder 12 and a seal ring 13 are interposed between the hollow portion IO and the communication pipe II, and slidably support the guide cylinder 12 or the communication pipe If.
A seal ring 13 maintains a seal between the hollow portion IO and the communication pipe If. A hole I4 is formed in the side surface of the piston rod 8, and this hole 14 is connected to the upper chamber 3 of the cylinder l.
and the hollow portion 10 are communicated with each other.

The piston 2 is formed with passages 15 and 16 that communicate the upper chamber 3 and the lower chamber 4. A check valve 99 is attached to the upper surface of the piston 2 and opens the passage I5 only when the pressure in the lower chamber 4 is greater than the pressure in the upper chamber 3.

Further, a leaf valve 17 is attached to the lower surface side of the piston 2 as an extension side damping force generating means that generates a damping force according to the operating speed when the piston 2 is extending.

This leaf valve 17 normally closes the passage 16, but when the pressure in the upper chamber 3 becomes higher than the pressure in the lower chamber 4, it gradually opens the passage 16 and allows fluid to pass through the passage 16. At the same time, it provides passage resistance to the fluid, thereby generating a damping force.

A space 18 is formed between the bottom member 7 and the base valve 9. This space department! 8 communicates with the reservoir chamber 6 through a passage 19 formed at the joint between the bottom member 7 and the base valve 9. The base valve 9 has a lower chamber 4
A passage 20 and two holes are formed to communicate the space 18 and the space 18. A check valve 22 that closes the passage 20 is attached to the upper surface side of the base valve 9, and this check valve 22 closes the passage 20 only when the pressure in the space 18, that is, the pressure in the reservoir chamber 6 is higher than the pressure in the lower chamber 4. The passage 20 is opened. On the lower surface facing the space ■8 of the base valve 9,
A leaf valve 23 is attached as a compression side damping force generating means that generates a damping force according to the operating speed when the piston 2 is compressed. This leaf valve 23 normally closes the passage 21, but the pressure in the lower chamber 4 is
8, that is, greater than the pressure in the reservoir chamber 6, the fluid is gradually allowed to pass through the passage 21 and provides passage resistance to the fluid, thereby generating a damping force. Further, a cylindrical member 24 is fitted and fixed in the axial center of the bottom member 7. This cylindrical member 24
The communication pipe II is fitted into the inside thereof, and the upper end thereof is fitted and fixed to the base valve 9 in a penetrating state.

The cylindrical member 24 has an annular groove 25 formed in its inner periphery, and passages 26 and 27 passing through the inner and outer surfaces of the annular groove 25, respectively, are formed in portions corresponding to the upper and lower ends of the annular groove 25. The upper passage 26 communicates with a passage 28 that communicates the upper surface and the inner peripheral surface of the base valve 9, and the lower passage 27 communicates with an annular groove 29 formed in the bottom member 7. The annular groove 29 communicates with a passage 30 that opens into the space 18 at one end and a bypass passage 32 (see FIG. 3.4) that opens into the space 3I below the insertion end of the cylindrical member 24. . Further, near the lower end of the cylindrical member 24, a passage 33 is formed that communicates with the wall surface of the cylindrical member 24, and the check valve 3 is biased upward by a spring (the spring is indicated by the reference numeral 34 in the figure).
5 (valve body) is installed. The check valve 35 is designed to block the inside of the cylindrical member 24 to prevent communication between the inside of the communication pipe II and the passage 33.

The passage 33 also communicates with a passage 36 of the bottom member 7 that opens into the space 18 at one end. The space 3I below the cylindrical member 24 includes a bypass passage 32. as shown by the dotted line in FIG. Annular 111129. Since the passage 27, the annular groove 259 and the passage 26.28 communicate with the lower chamber 4, the pressure of the lower chamber 4 acts as a force on the check valve 35 in addition to the elastic force of the spring 34. Therefore, the check valve 35 is activated when the pressure in the communication pipe 11 is greater than the pressure in the bypass passage 32, that is, the pressure in the upper chamber 3 is lower than the pressure in the lower chamber 4.
The communication pipe 11 and the bypass passage 32 are communicated only when the pressure is higher than the pressure, and the communication between the communication pipe II and the bypass passage 32 is blocked in other cases.

A relief valve 37 and a variable throttle 38 as contraction side flow rate adjusting means are interposed in the middle of the passage 30 that communicates the annular groove 29 and the space 18. The variable diaphragm 38 has a structure in which a plurality of orifices 38b, 38c, etc. having different opening areas are bored at set intervals around the periphery of a cylindrical main body 38a, and the main body 38a is connected to the bottom member 7. By rotating it from the outside, one of the orifices 38b, 38c, etc. can be freely selected and used.

In addition, the passage 33 and the space 18 near the lower end of the cylindrical member 24
A relief valve 39 and a variable throttle 40 as expansion side flow rate adjusting means are interposed in the middle of the passage 36 that communicates with the. This variable diaphragm 40 has the same configuration as the variable diaphragm 38, and the orifices 40b, 4 are opened by rotating the main body 40a from the outside of the bottom member 7 as necessary.
0c... can be freely selected and used.

Relief valves 37 and 39 are provided to block the passages 30.36 and prevent fluid from passing through these passages 30.36 at very low operating speeds of the piston 2.

In this embodiment, the passages 28, 26. Annular groove 251
Passage 27. Annular groove 291 passage 30. Space section 189 passage 1
9 constitutes a communication path A that communicates the lower chamber 4 and the reservoir chamber 6, and the hole 14. Hollow portion 10. Communication pipe 11. aisle 3
3.36. Space department! 8. The passage 19 constitutes a communication passage B that communicates the upper chamber 3 and the reservoir chamber 6 (see FIG. 1).

In the above configuration, when a tensile force is applied to the shock absorber and the piston 2 moves in the extension direction, the check valve 99 of the piston 2 closes the passage 15, so that the pressure in the upper chamber 3 increases. This allows the leaf valve I7 of piston 2 to pass! 6 to generate damping force. At this time, since the check valve 22 of the base valve 9 opens the passage 20, fluid corresponding to the volume of the piston rod 8 that is removed from the cylinder I is transferred from the reservoir chamber 6 to the passage 20.
9. Flows into the lower chamber 4 via the space 18 and the passage 20.

Further, the pressure in the upper chamber 3 acts on the upper part of the check valve 35 through the hole I4, the hollow portion 10, and the communication pipe 11.
29, the pressure is greater than the pressure in the lower chamber 4 that acts on the lower part of the check valve 35 through the bypass passage 32 and the space 31, so the check valve 35 is pushed downward and the communication pipe 11 and the passage 3
6 are in communication with each other, and the fluid in the upper chamber 3 passes through the relief valve 39 and the variable throttle 40 and exits from the space 18 to the reservoir chamber 6. Therefore, the damping force generated inside the shock absorber during the extension movement of the piston 2 is adjusted and controlled by appropriately selecting and switching the orifices 40b, 40c, . . . of the variable throttle 40. When the operating speed of the piston 2 is very low, the relief valve 39 closes the passage 36, so that the fluid does not pass through the variable throttle 40, but passes through a fixed orifice for very low speeds (not shown).

On the other hand, when a force in the compression direction is applied to this shock absorber and the piston 2 moves in the contraction direction, the check valve 99 of the piston 2 closes in the passage 15 as shown in FIG.
At the same time that the check valve 22 of the base valve 9 closes the passage 20, the check valve 22 of the base valve 9 closes the passage 20. Therefore, as the piston rod 8 is inserted into the cylinder I, the pressure in the upper chamber 3 and lower chamber 4 increases by an amount corresponding to its volume, and the leaf valve 23 of the base valve 9 opens the passage 21 to generate a damping force. do. At this time, the fluid in the lower chamber 4 flows through the passage 21 to the space 18 to the passage 19. Exit to reservoir room 6. Additionally, the fluid in the lower chamber 4 is transferred to the passage 28.2.
6. Annular groove 251 passage 27. Passage 30 via annular groove 29
It passes through the relief valve 37 and the variable throttle 38 in the middle of the space 18 and the passage 19. Exit to reservoir room 6. In this case, if the operating speed of the piston 2 is very low, the relief valve 37 closes the passage 30, so the fluid in the lower chamber 4 does not pass through the variable throttle 38, and the fluid in the very low speed (not shown) is closed. Pass through a fixed orifice.

By the way, when the piston 2 moves in the contraction direction in this way and the pressure in the upper chamber 3 increases together with the pressure in the lower chamber 4, this pressure increases in the hole 14. It acts on the upper part of the check valve 35 through the hollow 10° communicating pipe 11. However, at this time, the pressure in the upper chamber 3 is not greater than the pressure in the lower chamber 4 that acts on the lower part of the check valve 35 via the passage 28, the annular grooves 25, 29, the bypass passage 32, and the space 31 (same pressure, or small), the check valve 35 remains blocking communication between the communication pipe II and the passage 36, and the fluid no longer passes through the variable restrictor 40. Therefore, the damping force generated inside the shock absorber when the piston 2 retracts is reduced by the variable throttle 38.
The orifice 38b,
By carefully selecting 38c..., accurate adjustment control becomes possible.

Next, another embodiment corresponding to claim 1 of the present invention will be described. In the embodiments described below, some explanations regarding parts that overlap with those of the previous embodiments will be omitted, and the same parts will be denoted by the same reference numerals.

In FIG. 5.6, in the case of the shock absorber of this embodiment, the basic structure is almost the same as that of the previous embodiment, but the way in which the communication passage connecting the upper chamber 3 and the reservoir chamber 6 is provided,
The arrangement of the reservoir chamber 6 and the structure of the check valve provided in the piston 2 are partially different.

In the embodiment described above, a communication pipe passing through the piston 2 was used as a part of the communication passage connecting the upper chamber 3 and the reservoir chamber 6, or in the case of this embodiment, the communication pipe was used as a part of the communication passage that communicated the upper chamber 3 and the reservoir chamber 6. A passage 41 is formed in and this passage 41 is employed. A hole 42 communicating between the upper chamber 3 and the passage 4I is formed in the wall surface on the upper end side of the cylinder I, and a passage 43 communicating between the passage 41 and the inside of the cylindrical member 124 is formed in the base valve 9. ing.

Cylindrical member! 24 is closed at its upper end and opened at its lower end into a space 31 provided in the bottom member 7, into which a partition cylinder 44 is fitted along the axial direction. Cylindrical member 1
24 is defined by this partition member 44 into an outer annular groove 25 and an inner passage 45.
3 communicates with the inner passage 45 side. Further, a passage 33 communicating with the wall surface of the cylindrical member 124 is formed near the lower end of the cylindrical member 124, and a check valve 35 prevents communication between the passage 45 and the passage 33 by closing the passage 45 of the cylindrical member 124. (valve body) is installed. The passage 33 is
It communicates with a passage 36 in which a relief valve 39 and a variable throttle 40 as an extension side flow IN regulating means are interposed, and the passage 36 communicates with the space part 8. In addition, passages 26 and 27 are formed in side wall portions corresponding to the upper and lower ends of the annular groove 25 of the cylindrical member 124, respectively, to communicate the inner and outer surfaces. The upper passage 26 communicates with a passage 28 formed in the base valve 9 so that one end opens into the lower chamber 4, and the lower passage 27
It communicates with an annular groove 29 formed in the bottom member 7.

The annular groove 29 has a relief valve 37 on the way and a contraction side flow fft.
A passage 30 in which a variable throttle 38 as an FI adjusting means is interposed
This passage 30 communicates with the space I8.

In addition to the passage 30, the annular groove 29 communicates with a bypass passage 32 whose one end communicates with the space 31 as shown in FIG. Passage 27. Annular groove 29. The pressure in the lower chamber 4 is introduced into the space 31 via the bypass passage 32.

In the case of the shock absorber of this embodiment, instead of forming the reservoir chamber 6 between the cylinder 1 and the outer cylinder 5, a separate reservoir tank 46 provided with the reservoir chamber 6 is coupled to the bottom member 7. Therefore, since the reservoir chamber 6 is not provided inside, the internal structure of the outer cylinder 5 is simplified and manufacturing becomes easier.

The inside of the reservoir tank 46 is defined by a free piston 47 into an air chamber 48 and a reservoir chamber 6, and the reservoir chamber 6 communicates with the space 18 via a passage 19 formed in the bottom member 7. In the case of this embodiment, the communication passage that communicates the upper chamber 3 and the reservoir chamber 6 includes the hole 422 passage 41,
43, 45, 33.36. Space part 18. The communication path constituted by the passage 19 and communicating the lower chamber 4 and the reservoir chamber 6 is the passage 28.26. Annular groove 252 passage 27. Annular groove 2
9, i road 30. The space portion 1B is constituted by a passage 19.

In addition to the leaf valve 17 as a means for generating damping force on the extension side, the piston 2 also includes a check valve that opens the passage 15 during the contraction operation of the piston 2 to allow passage of fluid from the lower chamber 4 to the upper chamber 3. Leaf valve 49 that also functions as
is provided.

In addition, in the figure, 50 is an upper lid member provided at the upper end of the cylinder l and the outer cylinder 5, 51 is a protector for preventing the reservoir tank 46 from being deformed by thrown up stones, etc., and 52 is a reservoir tank. A plug 53 is used to remove air mixed into the chamber 6, and a plug 53 is used to seal air into the air chamber 48.

In this shock absorber constructed as described above, as in the case of the previous embodiment, when the piston 2 is retracted, the extension side flow i! Fluid is prevented from passing through a variable restrictor 40 as an adjusting means. Further, this shock absorber operates almost in the same way as the one in the previous embodiment, but since the piston 2 is provided with a leaf valve 49 that functions as a check valve,
By setting the spring rigidity of this leaf valve 49 to be different from that of the leaf valve 23 provided in the base valve 9, the damping characteristics during the contraction movement of the piston 2 can be made closer to the ideal damping characteristics without changing in multiple stages. Become. However, in the case of this shock absorber, if the spring rigidity of the leaf valve 49 is set too high, the pressure in the upper chamber 3 tends to decrease when the piston 2 contracts, so the spring rigidity of the leaf valve 49 is set too high. It is not desirable to do so. Furthermore, in Figure 5.6,
Solid line arrows indicate the flow of fluid when the piston 2 is extending, and dotted line arrows indicate the flow of fluid when the piston 2 is retracting.

Next, embodiments corresponding to claim 2 of the present invention will be described in seventh to seventh embodiments.
This will be explained based on an IO diagram.

In Fig. 7.8, the inside of the cylinder 1 is defined by the piston 2 into an upper chamber 3 and a lower chamber 4, and an outer cylinder 5 is arranged on the outer circumferential side of the cylinder 1, and together with the outer cylinder 5, a passage 4I is formed. ing. The passage 41 communicates with the upper chamber 3 through a hole 42 provided at the upper end of the cylinder l. Further, an upper lid member 50 and a bottom member 7 are provided at the upper and lower ends of the cylinder 1 and the outer cylinder 5, respectively, and a separate reservoir tank 46 is coupled to the outer side of the bottom member 7. A base valve 9 is provided between the bottom member 7 and the cylinder l, and a space 18 is formed between the base valve 9 and the bottom member 7. This space 18 is a passage! It communicates with the reservoir chamber 6 of the reservoir tank 46 via 9. In this embodiment as well, the bottom member 7 and the base valve 9 constitute a partition member between the cylinder I and the reservoir chamber 6.

The piston 2 has a passage 15 that communicates the upper chamber 3 and the lower chamber 4.
．． 16 are formed. A check valve 99 is installed on the upper surface of the piston 2 to open the passage 15 to allow fluid to flow from the lower chamber 4 to the upper chamber 3 when the piston 2 is retracting, and on the lower surface when the piston 2 is extending. A leaf valve 17 is attached as an extension side damping force generating means that opens the passage 16 and generates a damping force according to the operating speed.

On the other hand, the base valve 9 is formed with passages 20 and 21 that communicate the lower chamber 4 and the space 18.

Then, on the upper surface side of the base valve 9, there is a space created by opening the passage 20 when the piston 2 is extended. 8 (Reservoir chamber 6)
check valve 22 that allows fluid to flow from the lower chamber 4 to the lower chamber 4;
A leaf valve 23 is attached to the lower surface side as a compression side damping force generating means that opens the passage 21 when the piston 2 is compressed and generates a damping force according to the operating speed.

Further, a cylindrical member 24 that passes through the base valve 9 is fitted and fixed to the axial center of the bottom member 7.

A partition tube 44 is fitted into this cylindrical member 24, and the inside is defined by this partition member 44 into an outer annular groove 25 and an inner passage 45. A passage 2 penetrating the inner and outer surfaces is provided at a portion corresponding to the upper and lower ends of the annular groove 25 of the cylindrical member 24.
6.27 is formed, the upper passage 26 communicates with a passage 43 formed in the base valve 9 so that one end opens to the passage 41, and the lower passage 27 has one end opened to the base valve 9. It communicates with a passage 54 that opens into the space 31 provided. A passage 45 in the cylindrical member 24 connects the lower chamber 4 and the space 3.
1, and this third space is further communicated with a passage 55 whose one end opens into the space 18.

A variable throttle 40 is interposed in the middle of the passage 54 as a means for adjusting the flow rate on the expansion side, and a variable throttle 40 is installed in the middle of the passage 55 as a means for adjusting the flow rate on the contraction side.
A variable aperture 38 is also interposed as an adjusting means. Each variable throttle 40.38 has a plurality of orifices 4 on its outer periphery.
0b, 40c..., 38b, 38c", the main body part 4
By rotating 0a, 38a from the outside of the bottom member 7, the orifices 40b, 40c..., 38b, 3
In this embodiment, the holes 421, passages 41, 43, 26, . Annular groove 251 passage 27, 54. The upper chamber 3 and the lower chamber 4 communicate with each other through a communication path constituted by the space 31 and the passage 45,
Passage 45. Space 31, passage 55. Space part +8. aisle 19
The lower chamber 4 and the reservoir chamber 6 are in communication with each other through a communication path formed by the lower chamber 4 and the reservoir chamber 6. Further, reference numeral 56 in FIG. 8 is a cooling fin provided on the outer periphery of the reservoir tank 46.

In the above configuration, when the piston 2 moves in the extension direction, the check valve 99 closes and the pressure in the upper chamber 3 increases, which causes the leaf valve 1 provided on the piston 2 to increase.
7 opens to generate a damping force, and the fluid in the upper chamber 3 flows through the holes 421 passages 41° 43.26. Annular groove 251 passage 2
7,54. The lower chamber 4 passes through the space 31 and the passage 45 in sequence.
Exit to.

At this time, the fluid passes through a variable restrictor 40 that is interposed in the middle of the passage 54 and serves as an extension side flow rate adjustment means.

Further, when the piston 2 moves in the extension direction, the check valve 22 provided in the base valve 9 opens, and fluid corresponding to the volume of the piston rod 8 that is removed and removed from the cylinder I flows from the reservoir chamber 6 to the passage 19, the space 18, It flows into the lower chamber 4 via the passage 20.

When the piston 2 moves in the contraction direction, the piston 2
When the check valve 99 opens, the fluid in the lower chamber 4 escapes from the passage 15 to the upper chamber 3, and the pressures in both the upper chamber 3 and the lower chamber 4 rise by the amount that the piston rod 8 is inserted into the cylinder 1. As a result, the leaf valve 23 provided in the base valve 9 opens and generates a damping force, and the fluid in the lower chamber 4 flows through the passage 45, the space 31. Passage 55. Space section 181 passage 1
9 and exits to the reservoir chamber 6. At this time, the fluid passes through a variable restrictor 38 that is provided in the middle of the passage 55 and serves as a contraction side flow rate adjustment means. Furthermore, when the piston 2 is compressed, the pressure in the upper chamber 3 also increases, but since the upper chamber 3 and the lower chamber 4 communicate through the passage 15 and have the same pressure, the fluid is It does not pass through the variable aperture 40.

Therefore, in the case of this shock absorber, the damping force on the compression side can be adjusted and controlled independently only by the variable throttle 38 without being influenced by the variable throttle 40 which is the expansion side flow rate adjustment means.

In the embodiment described above, the reservoir chamber 6 is provided by connecting a separate reservoir tank 46 to the outside of the bottom member 7, and the passage 41 for guiding the fluid in the upper chamber 3 to the bottom member 7 is connected to the outer periphery of the cylinder l. I tried to place it on the side, but
For example, as shown in FIG. 9, a cylinder! A middle cylinder 57 may be interposed between the cylinder 1 and the outer cylinder 5, and the space between the cylinder 1 and the middle cylinder 57 may be used as the passage 41, and the space between the middle cylinder 57 and the outer cylinder 5 may be used as the reservoir chamber 6. It is possible.

Further, as shown in FIG. 10, a communication pipe If passing through a piston (not shown) and reaching an upper chamber (not shown) is fitted and fixed to the bottom member 7 via a cylindrical member 24, and this communication It is also possible for the tube 11 to be a passage 41 that leads the fluid in the upper chamber 3 to the bottom member 7 . In FIGS. 7 to 10, solid line arrows indicate the flow of fluid when the piston 2 is extending, and dotted line arrows indicate the flow of fluid when the piston 2 is retracting.

Advantages of the Invention As stated in claim 1 of the present invention, a communication path is provided to communicate the lower chamber and the reservoir chamber, and in the middle of the communication path, the fluid flows during the contraction operation of the piston. A contraction side flow rate adjustment means for adjusting the passing flow rate is provided, and a communication path is provided in the middle to communicate the upper chamber and the reservoir chamber.
an extension-side flow rate adjustment means that adjusts the flow rate of fluid passing during the piston extension operation; and a valve body that allows fluid to flow from the upper chamber to the reservoir chamber only when the pressure in the upper chamber is greater than the pressure in the lower chamber. Since the valve body opens the communication passage only when the piston is extending and closes when it is retracting, only the compression side flow rate adjustment means affects the adjustment control of the damping force when the piston is retracting. I come to do it.

Further, in the second aspect of the present invention, the piston is provided with a check valve that allows fluid to flow from the lower chamber to the upper chamber during the contraction operation, and the partition member is provided with a check valve that allows the fluid to flow from the lower chamber to the upper chamber during the piston expansion operation. A check valve is provided to allow fluid to flow from the reservoir chamber to the lower chamber, and a communication path is provided to communicate between the lower chamber and the reservoir chamber to adjust the flow rate of the fluid when the piston retracts. A compression side flow adjusting means is provided, and a communication passage is provided to communicate the upper chamber and the lower chamber, and an extension side flow IFI adjustment means is provided in the middle thereof to adjust the flow rate of fluid passing during the piston extension operation. With this design, when the piston is retracting, the pressures before and after the expansion side flow rate adjustment means become the same and the fluid does not pass through the expansion side flow rate adjustment means, so that when the piston is retracting, only the contraction side flow rate adjustment means will affect the damping force adjustment control.

As a result, in either case, the damping force on the extension side and the damping force on the contraction side can be adjusted and controlled completely independently, making it possible to obtain damping characteristics that better suit the needs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment corresponding to claim 1 of the present invention, FIG. 2 is a cross-sectional view taken along line ■--RO in FIG. 1, and FIG. 3 is a cross-sectional view taken along line Ill-1 in FIG. 4 is a sectional view taken along the line III--III of FIG. 2 during the piston retraction operation, and FIG. 5 is a sectional view of another embodiment corresponding to claim 1 of the present invention. , FIG. 6 is a cross-sectional view of the same embodiment in another direction,
FIG. 7 is a sectional view of an embodiment corresponding to claim 2 of the present invention, FIG. 8 is a sectional view of the same embodiment in another direction, and FIG. 9 is a sectional view of the embodiment corresponding to claim 2 of the present invention. A schematic sectional view showing another embodiment, FIG. 1O is a sectional view showing still another embodiment corresponding to claim 2 of the present invention. 1... Cylinder, 2... Piston, 3... Upper chamber, 4... Lower chamber, 6... Reservoir chamber, 7... Photol
9... base valve (partition member), 17... leaf valve (retention side damping force generating means)
, 22... Check valve, 23... Leaf valve (compression side damping force generating means), 35... Check valve (valve body)
, 38... Variable throttle (shrinking side flow Iffff throwing means 0.
...Variable throttle (growth side flow I! adjustment means), 99...Check valve, A...Communication path, B...Communication path. 3 people outside Figure 3

Claims (2)

[Claims] (1) The inside of the cylinder is defined by a piston into an upper chamber and a lower chamber, and a reservoir chamber is provided outside the cylinder.
Furthermore, an extension side damping force generating means for generating a damping force when the piston is extending and a contraction side damping force generating means for generating a damping force when the piston is retracting are provided. A check valve that allows fluid to flow from the chamber to the upper chamber is provided, and a check valve that allows fluid to flow from the reservoir chamber to the lower chamber when the piston is extended is provided on the partition member between the lower chamber and the reservoir chamber. In a shock absorber provided with a valve, a communication passage is provided that communicates the lower chamber with the reservoir chamber, and a contraction side flow rate adjusting means is provided in the middle of the passage for adjusting the flow rate of fluid passing during the contraction operation of the piston. On the other hand, a communication path is provided that communicates the upper chamber with the reservoir chamber, and an extension side flow rate adjustment means is provided in the middle of the communication path to adjust the flow rate of fluid passing during the extension operation of the piston. A shock absorber characterized by interposing a valve body that allows fluid to flow from an upper chamber to a reservoir chamber only when the pressure is greater than the pressure. (2) The inside of the cylinder is defined by a piston into an upper chamber and a lower chamber, and a reservoir chamber is provided outside the cylinder.
Furthermore, an extension side damping force generating means for generating a damping force when the piston is extending and a contraction side damping force generating means for generating a damping force when the piston is retracting are provided. A check valve that allows fluid to flow from the chamber to the upper chamber is provided, and a check valve that allows fluid to flow from the reservoir chamber to the lower chamber when the piston is extended is provided on the partition member between the lower chamber and the reservoir chamber. In a shock absorber provided with a valve, a communication passage is provided that communicates the lower chamber with the reservoir chamber, and a contraction side flow rate adjusting means is provided in the middle of the passage for adjusting the flow rate of fluid passing during the contraction operation of the piston. On the other hand, the shock is characterized in that a communication path is provided that communicates the upper chamber and the lower chamber, and an extension side flow rate adjustment means is interposed in the middle of the communication path to adjust the flow rate of fluid passing during the extension operation of the piston. absorber.