JPH09112620A - Liquid pressure damper for suspension for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid pressure damper for car suspension of such a structure that the operation parts of an expansion side rotary valve and a contraction side rotary valve are arranged in the same position on the periphery of a bottom member, with which the operating effectiveness of both rotary valves when they are mounted on a car is enhanced, the flow path of the bottom member is simplified, and the manufacturing costs are reduced. SOLUTION: Two rotary valves 37, 38 are installed up and down in the axial direction of a bottom member 8, in such an arrangement that their flow-in parts are situated inside of the valve body 57 and flow-out parts are situated in alignment on the outside of the valve body 57. A ring-shaped groove 62 is formed outside of the flow-out part of the expansion side rotary valve 37 and put in communication with a reserver 3 through the first vertical hole 69. The flow-out part of the contraction side rotary valve 38 is put in communication with this ring-shaped groove 62 through the second vertical hole 70. The two vertical holes are provided on the same straight line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber used for an automobile suspension, and more particularly to a hydraulic shock absorber capable of adjusting the damping force generated on the extension side and the damping force generated on the contraction side. Regarding vessels.

[0002]

2. Description of the Related Art As a hydraulic shock absorber of this type, a conventional hydraulic shock absorber shown in FIG.
0, those shown in FIG. 11 have been developed.

The hydraulic shock absorber 1 has a so-called multi-cylinder structure in which a reservoir 3 is arranged on the outer circumference of a cylinder 2, and the cylinder 2 has an upper chamber 4 and a lower chamber 5 inside. A defining piston 6 is fitted together with a piston rod 7, and a bottom member 8 defining the lower chamber 5 inside the cylinder 2 and the reservoir 3 is attached to the lower end thereof.
An expansion side leaf valve 9 (expansion side damping force generating valve) that generates a damping force according to the pressure difference between the upper chamber 4 and the lower chamber 5 when the piston 6 extends and the piston 6 A check valve 10 that allows the hydraulic fluid to flow from the lower chamber 5 to the upper chamber 4 during the contraction operation is provided, and the bottom member 8 has a pressure between the reservoir 3 and the lower chamber 5 during the contraction operation of the piston 6. A compression-side leaf valve 11 (compression-side damping force generation valve) that generates a damping force according to the difference, and a check valve 12 that allows the hydraulic fluid to flow from the reservoir 3 to the lower chamber 5 when the piston 6 extends. It is provided. Further, the upper chamber 4 of the cylinder 2 and the reservoir 3 are communicated with each other by the extension side bypass passage 13 formed from the outer peripheral portion of the cylinder 2 to the bottom member 8, and the lower chamber 5 of the cylinder 2 and the reservoir 3 are The contraction side bypass passages 14 formed in the bottom member 8 communicate with each other, and these bypass passages 13 and 14 are connected to each other.
An extension side rotary valve 15 and a contraction side rotary valve 16 that adjust the passage opening area by a manual operation from the outside are respectively provided.

The rotary valves 1 on the expansion side and the contraction side, respectively.
Reference numerals 5 and 16 denote a plurality of orifices a and b having different diameters on the outer circumference.
Is provided with a cylindrical body 17 having ..., By appropriately rotating this cylindrical body 17 from the outside by a manual operation,
Orifices a to be interposed in the bypass passages 13 and 14,
b ... Can be selectively switched. The rotary valves 15 and 16 are fitted to both ends of the lateral hole 18 formed through the bottom member 8 in the diametrical direction, and the inner portions of the respective cylindrical bodies 17 serve as the central portion of the lateral hole 18. , And communicates with the lower chamber 5 of the cylinder 2 through the center hole 19 of the bottom member 8 which intersects with the bottom member 8. The central hole 19 is shared by the flow path on the outflow side of the extension side bypass passage 13 and the flow path on the inflow side of the contraction side bypass passage 14. The flow path 2 on the inflow side of the extension side bypass passage 13 is provided at a position facing the outer circumference of each of the extending side and contracting side cylindrical bodies 17 of the bottom member 8.
0 and the flow path 21 on the outflow side of the contraction side bypass passage 14 are formed along the axial direction of the bottom member 8, respectively.

Since the hydraulic shock absorber 1 is constructed as described above, when a load is applied to the piston rod 7 in the extending direction, the hydraulic fluid flows in the direction shown by the arrow in FIG. At that time, the expansion side leaf valve 9 provided in the piston 6 generates a predetermined damping force according to the rotational position of the expansion side rotary valve 15. That is, in this case, when the piston 6 operates in the extension direction together with the piston rod 7,
While the upper chamber 4 in the cylinder 2 has a high pressure and the extension side leaf valve 9 generates a damping force, a part of the hydraulic fluid in the upper chamber 4 flows into the lower chamber 5 through the extension side bypass passage 13, Further, at the same time, the hydraulic fluid that has withdrawn from the piston 2 from the cylinder 2 flows into the lower chamber 5 from the reservoir 3 by opening the check valve 12. At this time, the flow rate of the hydraulic fluid that escapes to the lower chamber 5 through the extension-side bypass passage 13 is defined by the rotational position of the extension-side rotary valve 15 (the opening area of the selected orifices a, b ...). The damping force generated in the extension side leaf valve 9 depends on the rotational position of the rotary valve 15.

When a load in the contracting direction is applied to the piston rod 7, a hydraulic fluid flows in the direction shown by the arrow in FIG. 11, and at that time, the contracting side leaf valve 11
Generates a predetermined damping force according to the rotational position of the contraction side rotary valve 16. In this case, when the piston 6 operates in the contracting direction together with the piston rod 7, the check valve 10 of the piston 6 opens and the upper chamber 4 and the lower chamber 5 communicate with each other. Only high pressure, at this time the contraction side leaf valve 1
1 produces a damping force, and a part of the hydraulic fluid in the lower chamber 5 flows into the reservoir 3 through the contraction side bypass passage 14. At this time, the flow rate of the hydraulic fluid passing through the compression side bypass passage 14 is defined by the rotational position of the compression side rotary valve 14 (the opening area of the selected orifices a, b ...), and therefore the compression side leaf valve 11 is provided. The damping force generated at 1 depends on the rotational position of the rotary valve 16.

Incidentally, this similar technique is disclosed in, for example, Japanese Patent Laid-Open No.
No. 223536, etc.

[0008]

In the conventional hydraulic shock absorber 1 described above, the extension side rotary valve 15 and the contraction side rotary valve 16 are fitted into both ends of the lateral hole 18 of the bottom member 8, and Since the operation portions 22 of both rotary valves 15 and 16 are arranged at opposite positions on the outer peripheral surface of the bottom member 8, as shown in FIG. 12, when the hydraulic shock absorber 1 is mounted on a vehicle body as an automobile suspension, The operation of both rotary valves 15 and 16 becomes extremely difficult. That is,
When the hydraulic shock absorber 1 is mounted on a vehicle body as an automobile suspension, the outer region of the bottom member 8 is surrounded by a plurality of support links 23, various members 24, brackets 25, etc. It is practically impossible to secure a sufficient space at the reciprocal positions on the outer circumference, and the operation of the rotary valves 15 and 16 in a narrow space is forced.

In the hydraulic shock absorber 1 described above, the basic flow passage structure in the bottom member 8 is left as it is, and the lengths and formation positions of the flow passages are slightly changed. It is not impossible to align the 16 operation parts 22 at the same position on the outer circumference of the bottom member 8, but in such a case, it is unavoidable that the flow path is complicated and the manufacturing cost is increased. . That is,
In the case of the above hydraulic shock absorber 1, the extension side rotary valve 15
On the side, the working fluid flows from the outer peripheral side of the cylindrical portion 17 into the inside,
On the contrary, the contraction side rotary valve side 16 has a flow passage structure in which the working fluid flows from the inside of the cylindrical portion 17 to the outer peripheral side.
In order to align the operating portions 22 of both rotary valves 15 and 16 at the same position on the bottom member 8, as shown in FIG.
If the compression side rotary valve 16 is simply arranged directly below the expansion side rotary valve 15, the expansion side rotary valve 15
Inflow part 15a of the outlet side of the contraction side rotary valve 16
6b is located directly above, and as a result, the flow path 21 on the outflow side of the contraction side bypass passage 14 bypasses the extension side rotary valve 15 and the flow path 20 on the inflow side extending above it. There is no choice but to make a bent shape. When the flow path 21 is formed into a complicatedly bent shape as described above, a plurality of holes are formed in the bottom member 8 from multiple directions when the flow path 21 is formed, and the holes are communicated with each other inside the bottom member 8. A complicated and time-consuming operation such as providing a blind cover at a necessary hole end is forced, and an increase in manufacturing cost cannot be avoided.

Therefore, according to the present invention, the operation portion of the extension side rotary valve and the operation portion of the contraction side rotary valve are arranged at the same position on the outer periphery of the bottom member without complicating the flow path of the bottom member. Without increasing the manufacturing cost,
An object of the present invention is to provide a hydraulic shock absorber for an automobile suspension that can surely improve the operability of both rotary valves when mounted on a vehicle.

[0011]

As means for solving the above-mentioned problems, the invention of claim 1 is such that a working fluid is flowed between a cylinder filled with the working fluid and this cylinder. A reservoir, a piston that is slidably fitted into the cylinder and defines the inside into an upper chamber and a lower chamber, a piston rod that is coupled to the piston and that moves in and out of the cylinder together with the piston, and the piston is provided in the piston. The expansion side damping force generating valve that generates a damping force according to the pressure difference between the upper chamber and the lower chamber when the piston expands, and the piston from the lower chamber to the upper chamber when the piston contracts A valve body that allows the working fluid to flow in, a check valve that is provided on the bottom member at the lower end of the cylinder and that allows the working fluid to flow from the reservoir to the lower chamber when the piston extends, A compression-side damping force generation valve that is provided in the cylinder member and generates a damping force according to the pressure difference between the lower chamber and the reservoir when the piston contracts, and the upper chamber through the bottom member to the lower chamber or the reservoir. An extension side bypass passage, an extension side rotary valve interposed in the extension side bypass passage to adjust its passage opening area from the outside, a contraction side bypass passage extending from the lower chamber to a reservoir through a bottom member, A hydraulic shock absorber for an automobile suspension, comprising: a compression-side rotary valve that is interposed in the compression-side bypass passage and adjusts the passage opening area from the outside; both rotary valves having orifices on the outer circumference. A rotatable cylindrical body is provided, and the cylindrical body is arranged along the radial direction of the bottom member so that the operating portion is exposed on the outer peripheral surface of the bottom member. The expansion-side rotary valve and the contraction-side rotary valve are arranged vertically in the axial direction of the bottom member, and the inflow parts of both rotary valves are arranged inside each cylinder and the outflow part is formed in each cylinder. Set on the outer peripheral side of the body respectively, and further,
An annular groove is provided in the outer peripheral area of the outflow portion of the extension side rotary valve, and at least a part of the flow passage on the downstream side of the extension side rotary valve that constitutes the extension side bypass passage extends in the axial direction of the bottom member from the annular groove. On the other hand, the flow passage on the downstream side of the compression-side rotary valve that constitutes the compression-side bypass passage communicates with the annular groove on the same straight line as the flow passage on the downstream side of the extension-side rotary valve. Thus, the flow passage on the downstream side of the extension side rotary valve is shared as the flow passage after the annular groove of the compression side bypass passage. In such a case, the flow path structure formed in the bottom member is simplified, and the flow path on the contraction side rotary valve downstream side of the compression side bypass path and the expansion side rotary valve downstream side flow path on the expansion side bypass passage are formed. And can be simultaneously formed by a single drilling operation.

Further, in the second aspect of the present invention, the valve element provided on the piston is a compression-side damping force generating valve that generates a damping force according to the pressure difference between the lower chamber and the upper chamber when the piston contracts. , The working fluid was prevented from flowing through the extension side bypass passage when the piston contracted. That is,
During the contraction operation of the piston, the pressure of the upper chamber becomes low due to the action of the damping force generation valve provided in the piston, and therefore the flow of the hydraulic fluid in the extension side bypass passage from the upper chamber to the reservoir chamber does not occur. Therefore, the contraction-side generated damping force can be set only by the contraction-side rotary valve without being affected by the expansion-side rotary valve.

[0013]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. The same parts as those of the conventional one shown in FIGS. 10 and 11 are designated by the same reference numerals.

As shown in the schematic structure of FIG. 1, this hydraulic shock absorber has a middle cylinder 30 outside the cylinder 2 in which the piston 6 is fitted, and an outer cylinder 31 outside the middle cylinder 30.
And the upper and lower ends of the cylinder 2 and the outer cylinder 31 are sealed by the upper lid member 32 and the bottom member 8, respectively, and the upper end of the piston rod 7 connected to the piston 6 penetrates the upper lid member 32. And protrudes to the outside of the cylinder 2. The space between the cylinder 2 and the middle cylinder 30 serves as an annular path 34 that forms a part of the extension side bypass passage 33 described later, and the space between the middle cylinder 30 and the outer cylinder 31 is the working fluid between the cylinder 2. It is a reservoir 3 for the circulation of The cylinder 2 is filled with hydraulic fluid, and the reservoir 3
The working fluid is filled with a predetermined amount of gas. Further, in the piston 6 which defines the inside of the cylinder 2 into an upper chamber 4 and a lower chamber 5, an expansion side leaf valve 9 (expansion side damping force generation valve) that generates a damping force when the piston 6 expands,
A contraction-side auxiliary leaf valve 35 (compression-side damping force generation valve) that generates a damping force when the piston 6 contracts is provided, and the bottom member 8 includes a contraction-side leaf that generates a damping force when the piston 6 contracts. A valve 11 (a compression-side damping force generating valve) and a check valve 12 that allows the working fluid to flow from the reservoir 3 to the lower chamber 5 when the piston 6 extends.
Is provided. Further, the upper chamber 4 and the reservoir 3 further include the extension side bypass passage 3 including the annular passage 34.
3, the lower chamber 5 and the reservoir 3 are communicated with each other by a contraction side bypass passage 36. In the middle of each of these bypass passages 33, 36, an extension side for adjusting their passage opening area from the outside is provided. A rotary valve 37 and a compression-side rotary valve 38 are provided respectively.

As shown in detail in FIGS. 2 and 4, the piston 6 has a piston body 39 fitted in the cylinder 2.
40a, 40b for connecting the upper chamber 4 and the lower chamber 5 to each other
Are formed. The contraction side auxiliary leaf valve 35 is attached to the upper surface side of the piston body 39 so as to close the passage 40a, and the extension side leaf valve 9 is attached to the lower surface side so as to close the passage 40b. The contraction side auxiliary leaf valve 35 gradually opens the passage 40a due to the pressure difference when the pressure on the lower chamber 5 side becomes larger than the pressure on the upper chamber 4 side during the contraction operation of the piston 6, and the hydraulic fluid is It is allowed to flow from the lower chamber 5 into the upper chamber 4 through the passage 40a, and a flow resistance is given to the working fluid, whereby a predetermined damping force is generated. Similarly, the expansion-side leaf valve 9 is configured so that the pressure on the upper chamber 4 side during the expansion operation of the piston 6 is the same as that of the lower chamber 5.
When the pressure becomes higher than the side pressure, the pressure difference opens the passage 40b to allow the working fluid to flow from the upper chamber 4 to the lower chamber 5, and at that time, a predetermined damping force is generated. ing. The contraction-side auxiliary leaf valve 35 is set to generate a smaller damping force than the contraction-side leaf valve 11 on the bottom member 8 side.

On the other hand, the bottom member 8 is, as shown in detail in FIGS. 2 and 5, a substantially columnar bottom body portion 41 welded and fixed to the lower end of the outer cylinder 31, and the center of the upper end of the bottom body portion 41. The base valve 42 is coupled to the base cylinder 42. The base valve 42 is fixed to the lower end of the outer cylinder 31 by the stepped shoulder portion of the middle cylinder 3 and the bottom cylinder 41.
0 and the lower end of the cylinder 2 are sealed. A space 43 is provided between the bottom body 41 and the base valve 42.
Is formed, and the space 43 communicates with the reservoir 3 via a groove 44 formed on the upper surface of the bottom body 41. The base valve 42 is formed with passages 45a and 45b for communicating the lower chamber 5 in the cylinder 2 with the space 43, and the check valve 12 for closing the passage 45a is attached to the upper surface side thereof and the lower surface side thereof. The leaf valve 11 on the contraction side, which closes the passage 45b, is attached to this. The check valve 12 has a passage 45 when the piston 6 is extended.
a is opened to allow the working fluid to flow from the space 43 (reservoir 3) into the lower chamber 5, and the contraction side leaf valve 11 keeps the pressure on the lower chamber 5 side when the piston 6 contracts. When the pressure becomes higher than the pressure on the reservoir 3 side, the passage 45b is gradually opened due to the pressure difference, and the working fluid passes through the passage 45b to flow from the lower chamber 5 to the space 43.
The fluid is allowed to flow into the (reservoir 3), and a flow resistance is given to the hydraulic fluid to generate a predetermined damping force.

The contraction side leaf valve 11 and the check valve 12 are attached to the base valve 42 by a hollow rod 46 penetrating the base valve 42 and a nut 47 screwed to the upper end of the hollow rod 46.
The lower end of 6 has a center hole 29 formed in the bottom body 41.
The expansion side bypass passage 33 and the contraction side bypass passage 36 together with the hollow pin 48 fitted and fixed in the
It is designed to form each part of.

That is, the hollow rod 46 has through-holes 49 in the peripheral wall portion fitted in the base valve 42 on the upper end side and the peripheral wall portion fitted in the bottom body 41 on the lower end side, respectively.
a and 49b are formed, and the through hole 49a on the upper side is formed.
Is opened in a lateral hole 50 of the base valve 42 communicating with the annular passage 34 on the outer periphery of the cylinder 2, and a through hole 49b on the lower end side.
Is opened to the first lateral hole 51 of the bottom body portion 41 communicating with the reservoir 3. The hollow pin 48 is provided with land portions 52a and 52b at its upper end and lower end,
The land portions 52a and 52b are closely fitted in the hollow rod 46, and the upper and lower through holes 49a and 49b of the hollow rod 46 are formed between the land portions 52a and 52b and the inner wall of the hollow rod 46. An annular path 53 that communicates with each other is formed. The upper ends of the hollow rods 46 and the central holes 46a, 48a of the hollow pins 48 communicate directly with the lower chamber 5 in the cylinder 2, while the lower ends communicate with the bottom of the center hole 29 of the bottom body 41. The bottom portion of the center hole 29 communicates with the second lateral hole 54 of the bottom body portion 41 that communicates with the reservoir 3. And
In this way, the two passages formed by the hollow rod 46 and the hollow pin 48, that is, the through hole 49a, the annular passage 53,
A passage passing through the through hole 49b and a passage passing through the central holes 46a and 48a respectively constitute a part of each of the extension side bypass passage 33 and the contraction side bypass passage 36.

Further, the expansion side rotary valve 37 and the contraction side rotary valve 38 are vertically arranged on the bottom body portion 41, and the operation portions 55 of both are arranged so as to be exposed from the outer peripheral surface of the bottom body portion 41. It is set up. These rotary valves 37 and 38 have exactly the same structure, and the inflow portion and the outflow portion of the working fluids of both are aligned in the same direction.

Each of the rotary valves 37 and 38 has a housing 56 fitted and fixed to the bottom body 41, a valve body 57 as a cylindrical body rotatably housed in the housing 56, and the valve body 57. Locking mechanism 58 for locking at the rotation position of the, and a relief mechanism 59 that opens only when the pressure of the hydraulic fluid on the inflow side exceeds a set pressure.
And The housing 56 is formed in a cylindrical shape with a bottom, and the first lateral hole 51 of the bottom body 41 is formed in the bottom of the housing 56.
(In the case of the extension side rotary valve 37) or the second lateral hole 54 (in the case of the contraction side rotary valve 38) is formed with a through hole 60 as an inflow portion. In addition, the through hole 6 as an outflow portion is formed in the substantially center of the peripheral wall of the housing 56.
1 is formed, and an annular groove 62 is formed in the outer peripheral area of the through hole 61. The valve body 57 is
It has a schematic shape in which a cylindrical portion is extended from a cylindrical base portion 57a, and a plurality of orifices a, b, c having different diameters are formed on the peripheral wall of the cylindrical portion. These orifices a, b, c are located at axial positions corresponding to the through holes 61 of the housing 56, and as shown in FIG.
It is provided at intervals. In addition, the base portion 5 of the valve body 57
The end surface on the 7a side is exposed from the housing 56, and this portion serves as the operation portion 55. As shown in FIG. 7, the locking mechanism 58 includes a locking groove 63 formed on the inner peripheral surface of the housing 56 corresponding to the four-step operating positions of the operating portion 55,
Ball 64 held by base 57a of valve body 57
And a spring 65 for urging the ball 64 outward in the radial direction of the valve body 57.
When the ball 5 is rotated to any one of the four stages, the ball 64 has the locking groove 6 corresponding to that position.
3 is fitted. The positions of the operating portion 55 are specifically three positions where any one of the orifices a, b, and c faces the through hole 61, and a position where the peripheral wall of the valve body 57 closes the through hole 61. ing. The relief mechanism 59 includes an annular valve seat 66 formed in the bottom of the housing 56 so as to surround the peripheral edge of the through hole 60, and a valve plate that abuts the valve seat 66 and closes the through hole 60. 67 and a spring 68 for urging the valve plate 67 toward the valve seat 66. The through hole 60 is opened only when the pressure of the hydraulic fluid on the inflow side becomes larger than the urging force of the spring 68. It has become.

Further, the bottom main body 41 is formed with a first vertical hole 69 which communicates the groove 44 on the upper surface thereof with the annular groove 62 of the expansion side rotary valve 37, and at the position immediately below the first vertical hole 69. A second vertical hole 70 that connects the annular groove 62 of the valve 37 and the annular groove 62 of the compression-side rotary valve 38 is formed. These vertical holes 69 and 70 are formed on the same straight line, and during manufacturing, they are simultaneously drilled by one cutting operation. The first vertical hole 69 constitutes a flow path (flow path on the downstream side of the expansion side rotary valve) from the expansion side rotary valve 37 to the upper groove 44 of the expansion side bypass passage 33. The passage is also shared by a part of the flow passage from the compression side rotary valve 38 to the groove 44 in the compression side bypass passage 36 (the flow passage on the downstream side of the compression side rotary valve). That is, the flow path on the compression flow side of the compression bypass valve 36 downstream of the compression rotary valve is the annular groove 6 of the compression rotary valve 38.
2, the second vertical hole 70, the annular groove 62 of the extension-side rotary valve 37, the first vertical hole 69, and the groove 44.

As shown in detail in FIGS. 2 and 8, the upper lid member 32 includes a rod guide 71 slidably supporting the piston rod 7, and a rod seal 72 closely contacting the outer peripheral surface of the piston rod 7. And they are fixed to the upper end of the outer cylinder 31 by caulking in a superposed state. The rod guide 71 is provided with a passage 73 extending from a gap between the rod guide 71 and the piston rod 7 on the inner peripheral side thereof to the upper portion of the reservoir 3.
The passage 73 is opened and closed by a check lip 74 provided on the rod seal 72. The check lip 74 allows the fluid to flow from the upper chamber 4 side to the reservoir 3 side in the cylinder 2 and prevents the fluid from flowing from the reservoir 3 side to the upper chamber 4 side opposite thereto. There is. Therefore, the hydraulic fluid leaking from the gap between the piston rod 7 and the rod guide 71 is returned to the reservoir 3, but the enclosed gas above the reservoir 3 does not flow into the cylinder 2.

Reference numeral 75 in FIG. 2 is a retainer for supporting the suspension spring, which is caulked and fixed to the outer periphery of the outer cylinder 31, and 76 is connected to the lower end of the bottom member 8 to be connected to the wheel side member. The bush 77 is a communication hole formed in the cylinder 2 for communicating the upper chamber 4 and the annular passage 34.

Since this hydraulic shock absorber has the above-mentioned structure, as shown in FIG. 1, when a large load on the extension side is applied to the piston rod 7, the upper chamber 4 in the cylinder 3 becomes high pressure. The flow from the upper chamber 4 through the extension side leaf valve 9 into the lower chamber, and the extension chamber bypass passage 33 from the upper chamber 4 (annular passage 34 → lateral hole 44 → through hole 49a → annular passage 53 → through hole 49b). -> First lateral hole 51-> extension side rotary valve 37-> first vertical hole-> groove 44) and reservoir 3
And at the same time, a flow flows from the reservoir 3 into the lower chamber 5 through the check valve 12 so as to compensate for the volume of the piston rod 7 withdrawn from the cylinder 2 (see FIG. See the arrow inside.)
At this time, a flow resistance is applied to the hydraulic fluid passing through the extension side leaf valve 9 to generate a damping force. The generated damping force is generated by the position of the extension side rotary valve 37 interposed in the extension side bypass passage 33. It will be a value according to. That is, when the valve body 57 of the rotary valve 37 is set to the position that closes the through hole 61 of the housing 56, the working fluid does not pass through the extension side bypass passage 33 and the damping force generated in the extension side leaf valve 9 is reduced. When the orifices a, b, c of the valve body 57 are set to the positions where they are maximized and the orifices a, b, c of the valve body 57 are exposed to the through holes 61, the orifices a, b, c are set.
Amount of hydraulic fluid corresponding to the opening area of the expansion bypass passage 3
As a result, the damping force generated in the extension side leaf valve 9 becomes a value corresponding to the selected position.

On the other hand, as shown in FIG. 9, when a large load on the compression side is applied to the piston rod 7, the lower chamber 5 in the cylinder 2 has a high pressure and passes from the lower chamber 5 to the auxiliary leaf valve 35 on the compression side. Flow into the upper chamber 4, the flow from the lower chamber 5 through the contraction side leaf valve 11 into the reservoir 3, and the flow from the lower chamber 5 into the contraction side bypass passage 36.
(Hole 46a, 48a → Central hole 29 → Second horizontal hole 54 → Compression side rotary valve 38 → Second vertical hole 70 → Annular groove 62 of extension side rotary valve 37 → First vertical hole 69 → Groove 44) A flow that flows into the reservoir 3 is generated (see the arrow in the figure), and at this time, the compression side leaf valve 11 and the compression side auxiliary leaf valve 35 generate a damping force according to the position of the compression side rotary valve 38. That is, the contraction side rotary valve 38 sets the flow rate of the hydraulic fluid passing through the contraction side bypass passage 36 to a value corresponding to the rotational position (position) of the valve body 57, similarly to the expansion side rotary valve 37 described above. Therefore, the damping force generated in the contraction side leaf valve 11 and the contraction side auxiliary leaf valve 35 depends on the selected position.

When the piston 6 contracts, the working fluid in the lower chamber 5 flows into the upper chamber 4 through the contraction-side auxiliary leaf valve 35, so that the upper chamber 4 contracts when the piston 6 contracts. Therefore, the hydraulic fluid in the upper chamber 4 does not flow out to the reservoir 3 through the extension side bypass passage 33 when the piston 6 contracts. Therefore, the contraction-side generated damping force can be independently set only by the contraction-side rotary valve 38 without being influenced by the setting of the expansion-side rotary valve 37. Further, the contraction side leaf valve 11 and the contraction side auxiliary leaf valve 35 prevent the hydraulic fluid in the reservoir 3 from flowing into the upper chamber 4 through the expansion side bypass passage 33 when the piston 6 contracts. Is set, and the check valve 12 is set to a sufficiently low valve opening pressure so that the hydraulic fluid of the reservoir 3 does not flow into the lower chamber 5 through the contraction side bypass passage 36 during the expansion operation of the piston 6. Has been done.

Further, when the load applied to the piston rod 7 is small and the moving speed of the piston 6 is slow, the relief mechanism 59 of each rotary valve 37, 38 closes the through hole 60, so that the rotary valve 37. , 3
Bypass passage 3 regardless of the setting of position 8
The hydraulic fluid does not pass through 3, 36 and the rotary valve 3
Even when the damping forces of 7 and 38 are set to be small, the damping force can be reliably generated by the leaf valves 9, 11, and 35.

In this hydraulic shock absorber, the operating portions 35 of the extension side rotary valve 37 and the contraction side rotary valve 38 are arranged vertically at the same position on the outer circumference of the bottom member 8. Therefore, when mounted as a suspension in an automobile, it is possible to easily secure a sufficient operation space for both rotary valves 37 and 38. Therefore, the operability of both rotary valves 37 and 38 when mounted in a vehicle can be reliably improved.

In the case of this hydraulic shock absorber, the inflow portions (through holes 60) of both rotary valves 37 and 38 are aligned inside the valve body 57, and the outflow portion (61) is aligned on the outer peripheral side of the valve body 57. And the first vertical hole 69 that connects the annular groove 62 of the extension-side rotary valve 37 and the groove 44,
Since the annular groove 62 of the compression side rotary valve 38 and the second vertical hole 70 that communicates the annular groove 62 of the extension side rotary valve 37 are arranged on the same straight line, the extension side bypass passage 3
The first vertical hole 69 forming a part of 3 can be shared as the flow passage on the downstream side of the compression side rotary valve of the compression side bypass passage 36, which simplifies the flow passage itself, and at the time of manufacturing, The first vertical hole 69 and the second vertical hole 70 can be simultaneously formed by one cutting operation. Therefore, the flow path of the bottom member 8 can be easily formed, and the manufacturing cost can be significantly reduced.

[0030]

As described above, according to the first aspect of the invention, the expansion side rotary valve and the compression side rotary valve for adjusting the opening areas of the bypass passages on the expansion side and the contraction side are vertically moved in the axial direction of the bottom member. In addition, the inflow parts of both rotary valves are set inside the cylinders, and the outflow parts are set on the outer peripheral side of each cylinder, respectively. A groove is provided, and at least a part of the flow passage on the downstream side of the expansion-side rotary valve that forms the expansion-side bypass passage is formed by extending in the axial direction of the bottom member from the annular groove, while the compression-side bypass is formed. The compression-side rotary valve downstream side flow path forming the passage is formed so as to communicate with the annular groove on the same straight line as the expansion-side rotary valve downstream side flow path, and the expansion-side rotary valve rear-side flow path is formed. Flow side flow path Since it is also used as a flow passage after the annular groove of the compression side bypass passage, the entire flow passage of the bottom member is simplified, and the flow passage on the downstream side of the compression side rotary valve of the compression side bypass passage and the extension side bypass are provided. The flow passage on the downstream side of the rotary valve on the extension side of the passage can be simultaneously formed by a single drilling operation. Therefore, the operation part of the expansion side rotary valve and the operation part of the contraction side rotary valve can be arranged at the same position on the outer periphery of the bottom member without requiring the difficult flow path forming of the bottom member, and thus the manufacturing cost can be improved. Without increasing
It is possible to surely improve the operability of both rotary valves when mounted on a vehicle. Further, according to the invention of claim 2, the valve element provided in the piston further comprises a pressure difference between the lower chamber and the upper chamber when the piston contracts. The compression-side damping force generation valve that generates a damping force according to the above is used to prevent the hydraulic fluid from flowing through the expansion-side bypass passage when the piston contracts. Can be accurately set and adjusted only by the rotary valve on the compression side without being affected by.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing the same embodiment.

FIG. 3 is a view on the arrow A of FIG. 2 showing the same embodiment.

FIG. 4 is an enlarged cross-sectional view of portion B of FIG. 2 showing the same embodiment.

FIG. 5 is an enlarged cross-sectional view of a portion C of FIG. 2 showing the same form.

FIG. 6 is a cross-sectional view taken along the line EE in FIG. 5 showing the same embodiment.

FIG. 7 is a cross-sectional view taken along line FF of FIG. 5 showing the same embodiment.

FIG. 8 is an enlarged sectional view of a portion D in FIG. 2 showing the same embodiment.

FIG. 9 is a schematic cross-sectional view showing the same embodiment.

FIG. 10 is a schematic cross-sectional view showing a conventional technique.

FIG. 11 is a schematic cross-sectional view showing the same technique.

FIG. 12 is a perspective view of a front suspension portion of the vehicle.

FIG. 13 is a schematic cross-sectional view showing a conventional technique.

[Explanation of symbols]

2 ... Cylinder, 3 ... Reservoir, 4 ... Upper chamber, 5 ... Lower chamber, 6 ... Piston, 7 ... Piston rod, 8 ... Bottom member, 9 ... Extension leaf valve (extension side damping force generating valve), 11 ... Shrink Side leaf valve (shrinkage side damping force generation valve), 12 ... Check valve, 33 ... Extension side bypass passage, 35 ... Shrinkage side auxiliary leaf valve (valve element, shrinkage side damping force generation valve), 36 ... Shrinkage side bypass passage, 37 ... Expansion side rotary valve, 38 ... Contraction side rotary valve, 55 ... Operation part, 57 ... Valve body (cylindrical body), 60 ... Through hole (inflow part), 61 ... Through hole (outflow part), 62 ... Annular groove 69 ... 1st vertical hole (flow path of expansion side rotary valve backflow side), 70 ... 2nd vertical hole (flow path of contraction side rotary valve backflow side), a, b, c ... Orifice.

Claims (2)

[Claims] 1. A cylinder filled with hydraulic fluid, a reservoir in which the hydraulic fluid flows between the cylinder, and a cylinder slidably fitted in the cylinder to form an upper chamber and a lower chamber therein. And a piston rod that is connected to the piston and moves in and out of the cylinder together with the piston, and a damping force that is provided on the piston and that corresponds to the pressure difference between the upper chamber and the lower chamber when the piston extends. An expansion-side damping force generating valve that is generated, a valve body that is provided on the piston and allows the working fluid to flow from the lower chamber to the upper chamber when the piston contracts, and a piston provided on the bottom member at the lower end of the cylinder. A check valve that allows the flow of hydraulic fluid from the reservoir to the lower chamber during extension operation, and a check valve provided on the bottom member that responds to the pressure difference between the lower chamber and the reservoir during contraction operation of the piston. A compression-side damping force generating valve that generates a damping force, an extension-side bypass passage that extends from the upper chamber to the lower chamber or reservoir via the bottom member, and the passage opening area of the extension-side bypass passage An expansion-side rotary valve that is adjusted from the outside, a compression-side bypass passage that extends from the lower chamber to the reservoir through the bottom member, and a compression-side rotary that is interposed in the compression-side bypass passage and adjusts the passage opening area from the outside. A hydraulic shock absorber for an automobile suspension, comprising: a valve; and the rotary valves each having a rotatable cylindrical body having an orifice on an outer periphery thereof, the cylindrical bodies extending along a radial direction of the bottom member. , The operation portion is disposed so as to be exposed on the outer peripheral surface of the bottom member, and the expansion-side rotary valve and the compression-side rotary valve are Along with vertically arranging them in the axial direction of the Tom member, the inflow parts of both rotary valves are set to the inside of each cylinder, and the outflow parts are set to the outer peripheral side of each cylinder, respectively.
An annular groove is provided in the outer peripheral area of the outflow portion of the extension side rotary valve, and at least a part of the flow passage on the downstream side of the extension side rotary valve that constitutes the extension side bypass passage extends in the axial direction of the bottom member from the annular groove. On the other hand, the flow passage on the downstream side of the compression-side rotary valve that constitutes the compression-side bypass passage communicates with the annular groove on the same straight line as the flow passage on the downstream side of the extension-side rotary valve. A hydraulic shock absorber for an automobile suspension, characterized in that the flow passage on the downstream side of the extension side rotary valve is shared as a flow passage after the annular groove of the compression side bypass passage. 2. A vehicle according to claim 1, wherein the valve element provided on the piston is a compression-side damping force generation valve that generates a damping force according to the pressure difference between the lower chamber and the upper chamber when the piston contracts. Suspension hydraulic buffer.