JP2009108984A - Fluid pressure buffer - Google Patents

Abstract

A fluid pressure shock absorber having a stable damping force is provided.
An extension-side damping force generating mechanism has an extension-side check valve including a disk valve, and an intermediate chamber is provided between the check valve and a main disk valve. Further, the compression side damping force generation mechanism 9 has a compression side check valve including a disk valve 39, and an intermediate chamber 41 is provided between the check valve and the main disk valve 26. Thereby, it is possible to reliably avoid the phenomenon that the main disk valve 26 is lifted during the expansion stroke and the phenomenon that the main disk valve 14 is lifted during the contraction stroke. As a result, the damping force is stabilized in any situation.
[Selection] Figure 1

Description

  The present invention relates to an improvement of a fluid pressure shock absorber.

  In Patent Document 1, an oil seal is fixed to the back side of the outer peripheral portion of the main disk valve, and this oil seal is slidably fitted to the inner cylindrical portion of the valve member to form a back pressure chamber. At least one orifice (notch) extending from the outer peripheral end portion to the inner peripheral end portion is provided in the seat portion on the inner peripheral side with which the main disk valve contacts or separates, and the back pressure chamber is extended by the orifice to the extension side passage and There is a disclosure of a hydraulic shock absorber (a kind of fluid pressure shock absorber) that is always in communication with the contraction side passage. According to this hydraulic shock absorber, in the extremely low speed region of the piston speed, the hydraulic pressure of the expansion side passage and the contraction side passage is slightly introduced into the back pressure chamber by the orifice, thereby reducing the damping force in the extremely low speed region of the piston speed. As a result, it is possible to control the variation of the orifice area communicating with the back pressure chamber when the main disk valve is closed, and a stable orifice characteristic can be obtained even in the extremely low speed region of the piston speed. .

However, in the hydraulic shock absorber disclosed in Patent Document 1, during the extension stroke, the pressure in the upper chamber acts on the outer periphery of the main disk valve of the contraction-side damping mechanism to apply a force in the lifting direction, and the oil in the upper chamber In order to enter the back pressure chamber, and in the contraction stroke, the reverse mechanism makes it easy to lift each. When the main disk valve lifts unintentionally, a part of the oil liquid flows therethrough, so that a desired damping force cannot be obtained and the damping force becomes unstable.
JP 2006-10069 A

  Then, this invention makes it a subject to provide the fluid pressure buffer from which the stable desired damping force is obtained.

  In order to solve the above problems, the invention according to claim 1 of the present invention is characterized in that a cylinder chamber downstream of the main valve from the main valve is provided between the main valve and a cylinder chamber downstream of the main valve. A check valve that allows only the outflow of fluid to the main valve was disposed, and an intermediate chamber was provided between the check valve and the main valve.

  ADVANTAGE OF THE INVENTION According to this invention, the fluid pressure buffer which can obtain the stable desired damping force can be provided.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The fluid pressure shock absorber 1 of the first embodiment is a cylindrical hydraulic shock absorber 1 incorporated in a suspension device of an automobile.
A fluid pressure shock absorber 1 according to the first embodiment shown in FIG. 1 has a piston 3 slidably fitted in a cylinder 2 in which oil (a kind of fluid) is sealed. 2 is defined as a cylinder upper chamber 2A and a cylinder lower chamber 2B. The piston 3 is fixed to the lower end portion of the piston rod 4 with a nut 5. The tip end side of the piston rod 4 is inserted through a rod guide (not shown) and an oil seal (not shown) attached to the upper ends of the cylinder 2 and the outer shell (not shown) and extends to the outside. The cylinder lower chamber 2B is connected to a reservoir (not shown) via a base valve (not shown). In addition, oil liquid and gas are sealed inside the reservoir.

  The piston 3 is provided with an expansion side passage 6 and a contraction side passage 7 for communicating the cylinder upper chamber 2A and the cylinder lower chamber 2B. The fluid pressure shock absorber 1 allows the fluid in the expansion side passage 6 to flow. An extension side damping force generation mechanism 8 that controls to generate a damping force at the time of extension, and a contraction side damping force generation mechanism 9 that generates a damping force at the time of contraction by controlling the flow of oil in the contraction side passage 7. Have. The extension-side damping force generation mechanism 8 has a valve member 10 disposed at the end of the piston 3 on the cylinder lower chamber 2B side. The valve member 10 is formed in an annular shape, and the piston rod 4 is inserted through an inner peripheral portion (a central hole) thereof. The extension-side damping force generation mechanism 8 has an annular seat portion 13 protruding from the end surface of the piston 3 on the cylinder lower chamber 2B side, and the extension-side passage 6 opens inside the seat portion 13. In addition, an outer peripheral portion of a main disk valve 14 (main valve) that is formed in an annular shape and has flexibility is seated on the seat portion 13.

  The inner periphery of the main disc valve 14 is sandwiched between the piston 3 and the valve member 10, and opens when the outer periphery is separated from the seat portion 13 by bending. The main disc valve 14 has an annular oil seal 35 fixed to the back side (the lower side in FIG. 1) of the outer periphery. The oil seal 35 is slidably fitted to an inner cylindrical surface formed in the valve member 10, and a back pressure chamber 18 is formed in a space inside the oil seal 35. The oil seal 35 presses the main disc valve 14 toward the seat portion 13. That is, the oil seal 35 urges the main disc valve 14 in the valve closing direction. The main disc valve 14 has a notch disc 43 (see FIG. 2) and a closing disc 45 (see FIG. 3) stacked on the upstream side of the inner periphery. These are overlapped in this order from the upstream side (upper side in FIG. 1) to the downstream side (lower side in FIG. 1) of the closing disk 45, the notch disk 43, and the main disk valve 14.

  As shown in FIG. 4, the main disk valve 14 is formed with arc-shaped openings 47 on the concentric circles (in the first embodiment, the three openings 47 are equally arranged on the concentric circles). In addition, as shown in FIG. 2, the notch disk 43 is provided with notches 49 formed in a substantially T-shape in the circumferential direction (in the first embodiment, six notches 49 are equally provided. Each notch 49 extends from the end face of the notch disk 43 toward the center, and a tip extending toward the center branches and extends to both sides in the circumferential direction of the notch disk 43 so as to be substantially T-shaped. It is formed. In the extension-side damping force generation mechanism 8, the entire opening of the notch 49 on the end face of the notch disk 43 is closed by the closing disk 45.

  The extension side damping force generation mechanism 8 has a back pressure chamber inlet passage (upstream side orifice) for communicating the extension side passage 6 with the back pressure chamber 18. The back pressure chamber inlet passage includes a notch 49 in the notch disc 43 and an opening 47 in the main disc valve 14 and also includes a valve mechanism for adjusting the flow area of the back pressure chamber inlet passage. In the extension-side damping force generation mechanism 8, the main disk valve 14 is bent and opened. That is, when the main disc valve 14 is lifted and separated from the seat portion 13, the main disc valve 14 is separated from the notch disc 43, and this separated portion also constitutes an oil liquid passage. The flow path area increases. Furthermore, the extension side damping force generation mechanism 8 has a passage 19 for communicating the back pressure chamber 18 with the cylinder lower chamber 2B. Further, the extension side damping force generating mechanism 8 is a normally closed disk valve 20 that relieves the oil in the back pressure chamber 18 to the cylinder lower chamber 2B when the hydraulic pressure in the back pressure chamber 18 reaches the set pressure. A relief valve) is provided. In addition, a notch 21 (downstream orifice) that always connects the back pressure chamber 18 and the cylinder lower chamber 2B is provided on the outer peripheral portion of the disc valve 20.

  Further, the extension side damping force generation mechanism 8 allows an extension side check that allows the fluid in the extension side passage 6 to flow to the cylinder lower chamber 2B without passing through the back pressure chamber 18 when the main disk valve 14 is opened. Has a valve. The extension side check valve includes annular seat portions 30 and 31 provided on an end surface of the outer peripheral portion of the valve member 10 (an end surface facing the piston 3). These seat portions 30 and 31 are disposed concentrically with respect to the valve member 10, and the lower end portion of the piston 3 is fitted inside the upper end portion of the seat portion 31 disposed inside. Further, the extension side check valve has a disk valve 32 seated on the seat portions 30 and 31. The disc valve 32 is fitted to the piston 3 so that its inner peripheral portion can slide on the piston 3, that is, can move in the axial direction. The disc valve 32 is pressed toward the seat portions 30 and 31 by a coil spring 33 (biasing means) provided around the lower end portion of the piston 3. That is, the disc valve 32 is urged in the valve closing direction by the coil spring 33.

  An intermediate chamber 36 is formed between the extension side check valve and the main disk valve 14. As a result, when the main disk valve 14 is opened, the extension side check valve causes the oil in the extension side passage 6 to flow out into the cylinder lower chamber 2B via the intermediate chamber 36 and the disk valve 32. The seat portion 31 disposed on the inner side has a passage for allowing the oil liquid to flow between the main disc valve 14 and the disc valve 32.

  On the other hand, the contraction-side damping force generation mechanism 9 has a valve member 22 disposed at the end of the piston 3 on the cylinder upper chamber 2A side. The valve member 22 is formed in an annular shape, and the piston rod 4 is inserted through an inner peripheral portion (a central hole) thereof. Further, the contraction-side damping force generation mechanism 9 has an annular seat portion 25 projecting from the end surface of the piston 3 on the cylinder upper chamber 2 </ b> A side, and the contraction-side passage 7 opens inside the seat portion 25. In addition, an outer peripheral portion of a main disk valve 26 (main valve) that is formed in an annular shape and has flexibility is seated on the seat portion 25.

  The main disc valve 26 has an inner peripheral portion sandwiched between the piston 3 and the valve member 22 and opens when the outer peripheral portion is separated from the seat portion 25 by bending. The main disc valve 26 has an annular oil seal 28 fixed to the back side (upper surface in FIG. 1) of the outer periphery. The oil seal 28 is slidably fitted to an inner cylindrical surface formed in the valve member 22, and a back pressure chamber 29 is formed in a space inside the oil seal 28. The oil seal 28 presses the main disc valve 26 toward the seat portion 25. That is, the oil seal 28 urges the main disk valve 26 in the valve closing direction. In the main disk valve 26, a notch disk 44 (see FIG. 2) and a closing disk 46 (see FIG. 3) are stacked on the upstream side of the inner periphery. These are overlapped in this order from the upstream side (lower side in FIG. 1) to the downstream side (upper side in FIG. 1), the closing disk 46, the notch disk 44, and the main disk valve 26.

  As shown in FIG. 4, the main disk valve 26 is formed with arc-shaped openings 48 on concentric circles (in the first embodiment, three openings 48 are equally arranged on the concentric circles). Further, as shown in FIG. 2, the notch disk 44 is provided with a substantially T-shaped notch 50 in the circumferential direction (in the first embodiment, six notches 50 are equally provided). Each notch 50 extends from the end face of the notch disk 44 toward the center, and the tip extending toward the center branches and extends to both sides in the circumferential direction of the notch disk 44 so as to be substantially T-shaped. It is formed. In the contraction-side damping force generation mechanism 9, the entire opening of the notch 50 at the end face of the notch disk 44 is closed by the closing disk 46.

  The compression side damping force generation mechanism 9 has a back pressure chamber inlet passage (upstream side orifice) for communicating the compression side passage 7 with the back pressure chamber 29. The back pressure chamber inlet passage includes a notch 50 of the notch disc 44 and an opening 48 of the main disc valve 26, and also includes a valve mechanism for adjusting the flow area of the back pressure chamber inlet passage. In the contraction-side damping force generation mechanism 9, the main disk valve 26 is bent and opened. That is, the main disc valve 26 is lifted and separated from the seat portion 25, so that the main disc valve 26 is separated from the notch disc 44, and this separated portion also constitutes an oil liquid passage. The flow path area increases. Further, the compression side damping force generation mechanism 9 has a passage 11 for communicating the back pressure chamber 29 with the cylinder upper chamber 2A. Further, the compression-side damping force generating mechanism 9 is a normally closed disk valve 34 (relief of the hydraulic fluid in the back pressure chamber 29 to the cylinder upper chamber 2A when the hydraulic pressure in the back pressure chamber 29 reaches the set pressure. A relief valve) is provided. A notch 42 (downstream orifice) is provided on the outer peripheral portion of the disk valve 34 so that the back pressure chamber 29 and the cylinder upper chamber 2A always communicate with each other.

  Further, the contraction side damping force generating mechanism 9 performs a contraction side check that allows the fluid in the contraction side passage 7 to flow to the cylinder upper chamber 2A without passing through the back pressure chamber 29 when the main disk valve 26 is opened. Has a valve. The contraction side check valve has annular seat portions 37 and 38 provided on an end surface of the outer peripheral portion of the valve member 22 (an end surface facing the piston 3). These seat portions 37 and 38 are disposed concentrically with respect to the valve member 22, and the upper end portion of the piston 3 is fitted inside the lower end portion of the seat portion 38 disposed inside. Further, the contraction side check valve has a disk valve 39 seated on the seat portions 37 and 38. The disc valve 39 is fitted so that its inner peripheral portion can slide on the piston 3, that is, can move in the axial direction. The disc valve 39 is pressed toward the seat portions 37 and 38 by a coil spring 40 provided around the upper end portion of the piston 3. That is, the disc valve 39 is urged in the valve closing direction by the coil spring 40.

  An intermediate chamber 41 is formed between the contraction side check valve and the main disk valve 26. As a result, when the main disk valve 26 is opened, the contraction side check valve causes the fluid in the contraction side passage 7 to flow out to the cylinder upper chamber 2A via the intermediate chamber 41 and the disk valve 39. The seat portion 38 disposed on the inner side has a passage for allowing the oil liquid to flow between the main disk valve 26 and the disk valve 39. The oil seals 35 and 28 fixed to the main disk valves 14 and 26 are made of an elastic body such as rubber or synthetic resin, for example, and the amount of change in elastic force during the opening / closing stroke of the main disk valves 14 and 26 is small. Is set.

Next, the operation of the fluid pressure shock absorber 1 of the first embodiment will be described.
First, during the extension stroke, the piston 3 moves upward in FIG. As a result, the oil in the cylinder upper chamber 2A flows out through the extension side passage 6 toward the cylinder lower chamber 2B. At this time, the oil liquid corresponding to the retraction of the piston rod 4 from the cylinder 2 is supplied from the reservoir to the cylinder lower chamber 2B via the base valve, and the gas inside the reservoir expands to change the volume inside the cylinder 2. Is compensated. In the extension side damping force generation mechanism 8, the main disc valve 14 (main valve) is opened by receiving the hydraulic pressure in the extension side passage 6, and a damping force corresponding to the opening of the main disc valve 14 is generated. .

  Here, when the speed of the piston 3 is in the extremely low speed region (the initial stroke region of the piston rod 4), the outer peripheral portion of the main disc valve 14 remains seated on the seat portion 13. Further, when the speed of the piston 3 is in an extremely low speed region, the damping force is adjusted by slightly introducing the hydraulic pressure of the extension side passage 6 into the back pressure chamber 18 through the back pressure chamber inlet passage (upstream side orifice). To do. As a result, variation in the orifice area communicating with the back pressure chamber 18 when the main disk valve 14 is closed is suppressed, and the orifice characteristic when the speed of the piston 3 is in the extremely low speed range is stable, that is, the damping force is stable. To do.

  When the hydraulic pressure in the extension side passage 6 increases, the main disk valve 14 opens due to its deflection. By opening the valve mechanism by opening the main disk valve 14, the flow area of the back pressure chamber inlet passage increases, and the flow between the back pressure chamber inlet passage and the notch 21 (downstream orifice) downstream thereof is increased. The hydraulic pressure in the back pressure chamber 18 increases due to the road area difference. As a result, the pressure for opening the main disk valve 14 increases as the speed of the piston 3 increases, and the damping force also increases. When the hydraulic pressure in the back pressure chamber 18 reaches the set pressure, the disc valve 20 is opened. As a result, the hydraulic pressure in the back pressure chamber 18 is released to the cylinder lower chamber 2B, and an excessive increase in the valve opening pressure of the main disk valve 14 and, in turn, an excessive increase in the damping force on the extension side are prevented. When the main disc valve 14 is opened, the oil liquid flows into the intermediate chamber 36. As a result, the hydraulic pressure in the intermediate chamber 36 increases, the extension side check valve including the disc valve 32 is opened, and the oil that has flowed into the intermediate chamber 36 is discharged into the cylinder lower chamber 2B.

  In the contraction stroke described later, the hydraulic pressure in the cylinder lower chamber 2B is introduced into the back pressure chamber 18 through the notch 21 (downstream orifice), but the flow path in the notch 21 (downstream orifice). Since the area is larger than the flow path area of the back pressure chamber inlet passage (upstream side orifice), the hydraulic pressure in the back pressure chamber 18 is increased, and the main disk valve 14 is closed by the hydraulic pressure in the back pressure chamber 18. It is held in a valved state. Further, due to the extension side check valve including the disc valve 32 and the coil spring 33 (biasing means), the hydraulic pressure in the cylinder lower chamber 2B does not act directly on the main disc valve, and the hydraulic pressure in the intermediate chamber 36 is not affected by the back pressure chamber 18. Therefore, the degree of adhesion of the oil seal 35 to the inner cylindrical surface of the valve member 10 is increased. As a result, leakage of the oil liquid from the gap between the oil seal 35 and the valve member 10 is almost eliminated, and the lift of the main disk valve 14 is prevented.

  On the other hand, during the contraction stroke, the piston 3 moves downward in FIG. As a result, the oil in the cylinder lower chamber 2B flows through the contraction side passage 7 and flows out toward the cylinder upper chamber 2A. At this time, the amount of oil that the piston rod 4 has entered into the cylinder 2 is supplied from the cylinder lower chamber 2B to the reservoir via the base valve, and the gas inside the reservoir is compressed, so that the inside of the cylinder 2 is compressed. The volume change is compensated. The contraction-side damping force generating mechanism 9 receives the hydraulic pressure in the contraction-side passage 7 and opens the main disk valve 26 (main valve), and a corresponding damping force is generated depending on the opening degree of the main disk valve 26. .

  Here, when the speed of the piston 3 is in the extremely low speed region (the initial stroke region of the piston rod 4), the outer peripheral portion of the main disc valve 26 remains seated on the seat portion 25. Further, when the speed of the piston 3 is in an extremely low speed range, the damping force is adjusted by slightly introducing the hydraulic pressure of the contraction side passage 7 into the back pressure chamber 29 via the back pressure chamber inlet passage (upstream side orifice). To do. As a result, variation in the orifice area communicating with the back pressure chamber 29 when the main disk valve 26 is closed is suppressed, and the orifice characteristic when the speed of the piston 3 is in the extremely low speed range is stable, that is, the damping force is stable. To do.

  When the hydraulic pressure in the contraction side passage 7 increases, the main disc valve 26 opens due to its deflection. When the valve mechanism is opened by opening the main disk valve 26, the flow area of the back pressure chamber inlet passage is increased, and the flow between the back pressure chamber inlet passage and the notch 42 (downstream orifice) downstream thereof is increased. The hydraulic pressure in the back pressure chamber 29 increases due to the road area difference. As a result, as the speed of the piston 3 increases, the pressure for opening the main disk valve 26 increases, and the damping force also increases. Then, when the hydraulic pressure in the back pressure chamber 29 reaches the set pressure, the disc valve 34 is opened. As a result, the hydraulic pressure in the back pressure chamber 29 is released to the cylinder upper chamber 2A, thereby preventing an excessive increase in the valve opening pressure of the main disk valve 26, and thus an excessive increase in the damping force on the contraction side. When the main disc valve 26 is opened, the oil liquid flows into the intermediate chamber 41. As a result, the hydraulic pressure in the intermediate chamber 41 increases, the contraction side check valve including the disc valve 39 is opened, and the oil that has flowed into the intermediate chamber 41 is discharged to the cylinder upper chamber 2A.

  Note that, during the extension stroke described above, the hydraulic pressure in the cylinder upper chamber 2A is introduced into the back pressure chamber 29 via the notch 42 (downstream side orifice), but the flow path of the notch 42 (downstream side orifice). Since the area is larger than the flow path area of the back pressure chamber inlet passage (upstream side orifice), the hydraulic pressure in the back pressure chamber 29 is increased, and the main disc valve 26 is closed by the hydraulic pressure in the back pressure chamber 29. It is held in a valved state. Further, due to the compression side check valve including the disc valve 39 and the coil spring 40, the hydraulic pressure in the cylinder upper chamber 2A does not directly act on the main disc valve, and the hydraulic pressure in the intermediate chamber 41 is higher than the hydraulic pressure in the back pressure chamber 29. Since it is kept low, the degree of adhesion of the oil seal 28 to the inner cylindrical surface of the valve member 22 increases. As a result, there is almost no leakage of oil from the gap between the oil seal 28 and the valve member 22, and the main disk valve 26 is prevented from being lifted.

According to the first embodiment, the extension side damping force generation mechanism 8 has the extension side check valve including the disk valve 32, and the intermediate chamber 36 is provided between the check valve and the main disk valve 14 (main valve). Have. The compression side damping force generation mechanism 9 has a compression side check valve including a disk valve 39, and an intermediate chamber 41 is provided between the check valve and the main disk valve 26 (main valve).
As a result, the fluid pressure shock absorber 1 can reliably avoid the phenomenon in which the main disk valve 26 is lifted during the expansion stroke and the phenomenon in which the main disk valve 14 is lifted during the contraction stroke. As a result, the degree of freedom in setting the flow path area between the notches 21 and 42 (downstream side orifice) and the back pressure chamber inlet passage (upstream side orifice) is increased, and a desired damping force can be obtained.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG. The same or corresponding components as those in the first embodiment described above are given the same names, and the detailed description is omitted to simplify the description.
In the fluid pressure shock absorber 1A of the second embodiment shown in FIG. 5, the structure of the check valve formed in the extension side damping force generation mechanism 8A and the contraction side damping force generation mechanism 9A is the first shown in FIG. This is different from the check valve formed in the expansion side damping force generation mechanism 8 and the contraction side damping force generation mechanism 9 of the fluid pressure shock absorber 1 of the embodiment. This will be specifically described below.

  The extension-side damping force generation mechanism 8A is an extension-side check valve that allows oil in the extension-side passage 6 to flow to the cylinder lower chamber 2B without passing through the back pressure chamber 18 when the main disk valve 14 is opened. Have. This extension-side check valve has annular seat portions 30A and 31A provided on the end surface of the outer peripheral portion of the piston 3A (the end surface on the side facing the valve member 10A). These seat portions 30A and 31A are arranged concentrically with respect to the piston 3A, and the upper end portion of the valve member 10A is fitted inside the lower end portion of the seat portion 31A arranged inside. Further, the extension side check valve has a disk valve 32A seated on the seat portions 30A, 31A. The disc valve 32A is fitted so that its inner peripheral portion can slide on the outer peripheral portion of the valve member 10A, that is, it can move in the axial direction. The disc valve 32A is pressed toward the seat portions 30A and 31A by a coil spring 33A (biasing means) housed in a step on the outer peripheral side of the upper end portion of the valve member 19A. That is, the disc valve 32A is biased in the valve closing direction by the coil spring 33A.

  Further, in the extension-side damping force generation mechanism 8A, an intermediate chamber 36A is formed between the extension-side check valve and the main disk valve 14. As a result, when the main disk valve 14 is opened, the extension side check valve causes the oil in the extension side passage 6 to flow out into the cylinder lower chamber 2B via the intermediate chamber 36A and the disk valve 32A. The seat portion 31A disposed on the inner side has a passage for allowing the oil liquid to flow between the main disc valve 14 and the disc valve 32A.

  Further, the contraction side damping force generation mechanism 9 </ b> A allows the contraction side check to allow the oil in the contraction side passage 7 to flow to the cylinder upper chamber 2 </ b> A without passing through the back pressure chamber 29 when the main disk valve 26 is opened. Has a valve. The contraction side check valve has annular seat portions 37A and 38A provided on the end surface of the outer peripheral portion of the piston 3A (the end surface on the side facing the valve member 22A). These seat portions 37A, 38A are arranged concentrically with respect to the piston 3A, and the lower end portion of the valve member 22A is fitted inside the upper end portion of the seat portion 38A arranged inside. Further, the contraction side check valve has a disc valve 39A seated on the seat portions 37A, 38B. The disc valve 39A is fitted so that its inner periphery can slide on the outer periphery of the valve member 22A, that is, it can move in the axial direction. The disc valve 39A is pressed toward the seat portions 37A and 38A by a coil spring 40A (biasing means) housed in a step on the outer peripheral side of the lower end of the valve member 22A. That is, the disc valve 39A is biased in the valve closing direction by the coil spring 40A.

  In the contraction-side damping force generation mechanism 9A, an intermediate chamber 41A is formed between the contraction-side check valve and the main disk valve 26. As a result, when the main disk valve 26 is opened, the contraction side check valve causes the oil in the contraction side passage 7 to flow out to the cylinder upper chamber 2A via the intermediate chamber 41A and the disk valve 39A. The seat portion 38A disposed on the inner side has a passage for allowing the oil liquid to flow between the main disc valve 26 and the disc valve 39A.

  According to the second embodiment, the fluid pressure shock absorber 1A can obtain the same operations and effects as the fluid pressure shock absorber 1 of the first embodiment.

The characteristic structure of the present invention, that is, the extension-side damping force generation mechanism 8 and the contraction-side damping force generation mechanism 9 in the first embodiment, and the extension-side damping force generation mechanism 8A and the contraction-side damping force generation in the second embodiment. The check valve of the mechanism 9A is a monotube shock absorber, or a solenoid actuator provided inside the cylinder, and a damping force adjustment type fluid pressure shock absorber that can control the opening and closing of the poppet valve by an energizing current to the coil of the solenoid actuator ( For example, you may apply to Unexamined-Japanese-Patent No. 2006-292092). The present invention is also applicable to a fluid pressure shock absorber in which a damping force generation mechanism is provided outside the cylinder.
Each check valve may be configured by replacing each coil spring 33, 40, 33A, 40A (biasing means) with a disc spring or the like.
Further, the disk springs 33, 40, 33A, 40A are omitted by clamping the disk valves 32, 39, 32A, 39A of the check valves by the piston 3 or 3A and the valve members 10, 22, 10A, 22A. You can also.

It is sectional drawing of the principal part of the fluid pressure buffer of 1st Embodiment. It is a top view of the notch disk of 1st Embodiment and 2nd Embodiment. It is a top view of the obstruction disk of a 1st embodiment and a 2nd embodiment. It is a top view of the main disc valve of a 1st embodiment and a 2nd embodiment. It is sectional drawing of the principal part of the fluid pressure buffer of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid pressure buffer, 2 cylinders, 2A cylinder upper chamber, 2B cylinder lower chamber, 3 piston, 4 piston rod, 6 expansion side passage, 7 contraction side passage, 8 expansion side damping force generation mechanism, 9 contraction side damping force generation Mechanism, 10, 22 Valve member, 13, 25 Seat part (main valve side), 14, 26 Main disc valve (main valve), 18, 29 Back pressure chamber, 30, 37 Seat part (check valve outside), 31, 38 Seat part (inside check valve), 32, 39 Disc valve (check valve), 33, 40 Coil spring (biasing means), 36, 41 Intermediate chamber, 47, 48 Opening (back pressure chamber inlet passage), 49, 50 Notch (back pressure chamber entrance passage)

Claims (3)

A cylinder filled with fluid, a piston slidably fitted in the cylinder, defining the inside of the cylinder in two cylinder chambers, one end connected to the piston, and the other end to the outside of the cylinder A piston rod that extends to the main valve, a main valve that generates a damping force by controlling the flow of fluid generated by sliding of the piston, and a back pressure chamber that applies an internal pressure in the valve closing direction to the main valve; A back pressure chamber inlet passage for introducing a fluid into the back pressure chamber, and controlling the valve opening of the main valve by introducing a part of the fluid into the back pressure chamber via the back pressure chamber inlet passage. In the fluid pressure shock absorber,
Between the main valve and the cylinder chamber on the downstream side of the main valve, a check valve that allows only the outflow of fluid from the main valve to the cylinder chamber on the downstream side of the main valve is disposed. A fluid pressure shock absorber, wherein an intermediate chamber is provided between the valve and the main valve. The check valve includes a disk valve fitted to the piston and having an outer peripheral portion seated on the valve member, and an urging means for urging the disk valve in a valve closing direction. 2. The fluid pressure shock absorber according to 1. The check valve includes a disk valve fitted to the valve member and having an outer peripheral portion seated on the piston, and biasing means for biasing the disk valve in a valve closing direction. 2. The fluid pressure shock absorber according to 1.

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