JP2014149003A - Fluid pressure shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid pressure shock absorber for restraining increase of costs while maintaining a performance.SOLUTION: In the fluid pressure shock absorber 1a, an annular groove part 36 communicated with an orifice 35 provided to an inner cylinder 3 is formed on an inner periphery of a sub-cylindrical part 16 of a front cylindrical member 14, and a buffering annular groove part 37 is formed nearer an opening end of the sub-cylindrical part 16 of the front cylindrical member 14 than the annular groove part 36. Also, a passage cross sectional area of the annular groove part 36 is set larger than that of the buffering annular groove part 37. Thereby, increase of costs can be restrained while maintaining a performance.

Description

  The present invention relates to a fluid pressure shock absorber used for, for example, a railway vehicle.

  Conventionally, a railway vehicle has been provided with a fluid pressure damper (a railway vehicle yaw damper) that suppresses the carriage from meandering (yawing) in the horizontal direction with respect to the vehicle body. Therefore, various devices for discharging bubbles in the cylinder are applied to the fluid pressure shock absorber used in the sideways state.

  For example, in the case of the oil damper used in the lateral direction, in the case of the oil damper used in the lateral direction, since air bubbles stay at the axial end of the inner cylindrical side wall which is the upper side in the installed state, the axial end of the inner cylindrical side wall An air vent hole (also used as an orifice for generating damping force) is provided in the upper part of the vicinity of the portion, and an annular surface communicating with the air vent hole is formed on the inner peripheral surface of the concave portion of the front lid to which the end portion of the inner cylinder is fitted. There is a passage. Then, the air bubbles staying in the inner cylinder are discharged from the air vent hole into the working fluid in the lower part of the reservoir through the annular passage. Further, in this oil damper, seal members for sealing between the inner peripheral surface of the concave portion of the front lid and the outer peripheral surface of the inner cylinder are respectively disposed on both sides in the axial direction of the annular passage. Further, the annular passage communicates with an ejection pipe disposed in the working fluid below the reservoir.

JP 11-344068 A

  However, in the oil damper described in Patent Document 1, when the piston speed increases and the pressure in the annular passage rises, the working fluid passes from the annular passage to the inner peripheral surface of the recess of the front lid and the outer peripheral surface of the inner cylinder. There is a problem that the aeration is caused by being ejected into the inner cylinder from between the gaps, but the ejection of the working fluid is suppressed by each seal member. However, in this structure, the number of parts increases and the number of assembly steps also increases, so an increase in cost is inevitable. Further, when the piston speed increases and the flow rate flowing from the inner cylinder to the reservoir chamber increases, the flow rate of the hydraulic fluid is throttled by the ejection pipe, so that the back pressure is applied to the valve mechanism and the required performance cannot be obtained. There is a fear.

  And this invention aims at providing the fluid pressure buffer which suppresses cost increase, maintaining performance.

  As means for solving the above-mentioned problems, the present invention provides an annular structure in which both ends of an outer cylinder and an inner cylinder arranged concentrically are closed with lids, and a working fluid and a gas are sealed between the two. A fluid pressure shock absorber comprising a radially extending annular passage and a damping force generating orifice at a fitting portion between at least one end portion of the inner cylinder and a cylindrical portion provided in the lid body The annular passage communicates with the liquid chamber in the inner cylinder via the damping force generating orifice, and the annular passage is closer to the opening end side of the tubular portion than the annular passage. An annular space smaller than the passage cross-sectional area is formed.

  The fluid pressure shock absorber of the present invention can simplify the structure while maintaining the performance, and can reduce the cost.

FIG. 1 is a cross-sectional view showing a fluid pressure shock absorber according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a main part of the fluid pressure shock absorber according to the first embodiment of the present invention. FIG. 3 is an enlarged view of a main part of a fluid pressure shock absorber according to the second embodiment of the present invention. FIG. 4 is an enlarged view of a main part of a fluid pressure shock absorber according to a third embodiment of the present invention. FIG. 5 is an enlarged view of a main part of a fluid pressure shock absorber according to a fourth embodiment of the present invention. FIG. 6 is an enlarged view of a main part of a fluid pressure shock absorber according to a fifth embodiment of the present invention. FIG. 7 is an enlarged view of a main part of a fluid pressure shock absorber according to a sixth embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to FIGS.
The fluid pressure shock absorbers 1a to 1e according to the first to fifth embodiments are employed, for example, as horizontal motion dampers that are attached in a horizontally placed state between a bogie and a vehicle body of a railway vehicle. Moreover, the fluid pressure shock absorber 1f according to the sixth embodiment is employed, for example, as a vertical motion damper that is attached to a suspension device of an automobile in a vertically placed state.

First, the fluid pressure shock absorber 1a according to the first embodiment will be described with reference to FIGS.
As shown in FIG. 1, the fluid pressure shock absorber 1 a according to the first embodiment includes an outer cylinder 2 and an inner cylinder 3 arranged concentrically with the outer cylinder 2. Openings at both ends of the outer cylinder 2 and the inner cylinder 3 are closed by a front lid 4 and a rear lid 5, respectively. An annular reservoir chamber 6 is formed between the inner peripheral surface of the outer cylinder 2 and the outer peripheral surface of the inner cylinder 3.
For convenience of explanation, the following description will be made with the left side in the figure (when the sign is viewed upright), that is, the bracket 10 side as the front side, and the right side in the figure, that is, the bracket 11 side as the rear side.

  The front lid 4 closes the front end openings of the outer cylinder 2 and the inner cylinder 3 and also has a guide function for the piston rod 28. The front lid body 4 has an insertion hole 12 through which the piston rod 28 is inserted, and the front plate member 13 that closes the front end opening of the outer cylinder 2 and the rear surface region of the front plate member 13 toward the rear. The front cylindrical member 14 is integrally connected and closes the front end opening of the inner cylinder 3. The front cylindrical member 14 is integrally protruded from the main cylindrical portion 15 and the outer peripheral portion of the rear surface of the main cylindrical portion 15 and is inserted between the inner cylinder 3 and the outer cylinder 2. Part 16. A first seal member 20 is disposed between the inner peripheral surface of the insertion hole 12 of the front plate member 13 and the outer peripheral surface of the piston rod 28. Between the inner peripheral surface of the front cylindrical member 14 and the outer peripheral surface of the piston rod 28, second and third seal members 21 and 22 are disposed with an interval in the axial direction.

  On the other hand, the rear lid 5 is integrally connected to the rear plate-like member 25 that closes the rear end opening of the outer cylinder 2 from the substantially central portion of the front surface of the rear plate-like member 25 toward the front. The rear columnar member 26 closes the rear end opening of the cylinder 3. In addition, the bracket 11 for connection with the vehicle body side is fixed to the rear plate member 25.

  A piston 27 is disposed in the inner cylinder 3 so as to be slidable in the axial direction. One end of a piston rod 28 is connected to the piston 27, and the other end of the piston rod 28 extends through the front lid 4 in a liquid-tight manner to the outside of the outer cylinder 2. Note that a connecting bracket 10 that is connected to the carriage side is fixed to the other end of the piston rod 28.

  The inner cylinder 3 is partitioned by a piston 27 into a rod side oil chamber 29 and an anti-rod side oil chamber 30. Hydraulic oil (hydraulic fluid) is sealed in the rod-side oil chamber 29 and the anti-rod-side oil chamber 30, respectively. The piston 27 is provided with a check valve 31 that allows only the flow of hydraulic oil from the non-rod side oil chamber 30 to the rod side oil chamber 29. In addition, a check valve 32 that allows only the flow of hydraulic oil from the reservoir chamber 6 to the anti-rod-side oil chamber 30 is disposed on the rear columnar member 26 of the rear lid body 5.

  Further, referring also to FIG. 2, the upper peripheral wall of the front end portion of the inner cylinder 3, that is, the fitting portion of the inner cylinder 3 with the sub-cylindrical portion 16 of the front cylindrical member 14 constituting the front lid 4. An orifice 35 is formed in the upper peripheral wall. The orifice 35 extends in the radial direction. The orifice 35 functions as a damping force generating orifice and as an air bleeding orifice. On the inner peripheral surface of the sub-cylindrical portion 16 of the front side cylindrical member 14, an annular groove portion 36 is formed as an annular passage communicating with the orifice 35 provided in the inner cylinder 3. The cross section of the annular groove 36 is formed in a substantially rectangular shape. Further, on the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14, an annular space is provided on the rear side of the annular groove portion 36, that is, on the opening end side of the sub-cylindrical portion 16 of the front cylindrical member 14 with respect to the annular groove portion 36. The buffering annular groove 37 is formed. The cross section of the buffering annular groove 37 is also formed in a substantially rectangular shape. The passage sectional area of the annular groove 36 is set larger than the passage sectional area of the buffering annular groove 37. A rear end portion of a third flow path 43 of a communication flow path 40 to be described later communicates with a lower portion of the annular groove portion 36. Further, the front end portion of the ejection pipe 38 is inserted into the lower end portion of the sub tubular portion 16 of the front side tubular member 14. The portion of the ejection pipe 38 other than that inserted through the sub cylindrical portion 16 of the front cylindrical member 14 is disposed in the hydraulic oil in the lower reservoir chamber 6. The front end opening of the ejection pipe 38 faces the lower part of the annular groove 36. The housing groove provided on the inner peripheral surface of the front cylindrical member 14 on the front side of the annular groove 36 is formed between the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 and the outer peripheral surface of the inner cylinder 3. A seal member 39 (O-ring) that seals the gap is accommodated.

  In the lower part of the front cylindrical member 14 of the front lid body 4, a communication flow path 40 that communicates the rod side oil chamber 29 of the inner cylinder 3 and the annular groove portion 36 provided in the sub cylindrical portion 16 of the front cylindrical member 14. Is provided. The communication channel 40 includes a first channel 41 communicating with the rod-side oil chamber 29 and extending in the axial direction, a second channel 42 communicating with the first channel 41 and extending in the radial direction, and the first channel 41. The third flow path 43 includes a third flow path 43 that communicates with the two flow paths 42 and communicates with the lower portion of the annular groove 36 and extends in the axial direction. The first flow path 41 extends in the axial direction by forming a concave inner peripheral surface of the main cylindrical portion 15 of the front cylindrical member 14 in a concave shape. The second flow path 42 is provided below the main tubular portion 15 of the front tubular member 14 and extends in the radial direction. The second flow path 42 is provided with a small diameter flow path 42 a that communicates with the front portion of the first flow path 41, communicates with the small diameter flow path 42 a, and is provided below the small diameter flow path 42 a. The large-diameter channel 42b communicates with the front end portion. The third flow path 43 extends in the axial direction from the lower portion of the main tubular portion 15 of the front tubular member 14 to the lower portion of the sub tubular portion 16, and communicates with the lower portion of the annular groove portion 36. The second flow path 42 of the communication flow path 40 is provided with a pressure regulating valve 45 that opens and closes as the piston 27 moves.

  As shown in FIG. 2, the pressure regulating valve 45 is disposed in the second flow path 42 of the communication flow path 40 and is supported by a valve main body 46 that is movably supported along the radial direction of the front cylindrical member 14. Arranged between the base 47 supported in the radial flow path 42b and the valve main body 46 and the base 47, the valve main body 46 is urged toward the small diameter flow path 42a so that the small diameter flow path 42a is normally closed. And a spring 48. The valve body 46 includes a shaft portion 50 that fits into the small-diameter channel 42a, a plate-like portion 51 that is integrally connected from the lower end of the shaft portion 50 and substantially matches the inner diameter of the large-diameter channel 42b, and the plate It is comprised from the cylindrical part 52 hang | suspended below from the outer periphery of the shape part 51. As shown in FIG. The outer diameter of the base end portion of the shaft portion 50 substantially matches the inner diameter of the small-diameter channel 42a. The length of the shaft portion 50 substantially matches the height of the small diameter channel 42a. The shaft portion 50 tapers upward. The outer peripheral portion of the upper surface of the plate-like portion 51 is inclined downward. The base 47 includes a base plate portion 53 that is supported on the lower inner peripheral surface of the large-diameter channel 42b, and a base shaft portion 54 that protrudes upward from the center of the upper surface of the base plate portion 53. The The spring 48 is disposed between the lower surface of the plate-like portion 51 of the valve body 46 and the upper surface of the base plate portion 54 around the base shaft portion 53 of the base 47. Further, the space between the lower end of the cylindrical portion 52 of the valve body 46 and the upper surface of the base plate portion 54 of the base 47 faces the front end opening of the third flow path 43.

Next, the operation of the fluid pressure shock absorber 1a according to the first embodiment of the present invention will be described.
The fluid pressure shock absorber 1a according to the first embodiment is mounted horizontally between the carriage and the vehicle body, and the bracket 10 on the piston rod 28 side is connected to the carriage, and the bracket on the outer cylinder 2 side is connected to the vehicle body. 11 are connected.

  When the carriage and the vehicle body move relative to each other in the horizontal direction, the piston rod 28 expands and contracts. As a result, during the extension stroke of the piston rod 28, the hydraulic oil in the rod-side oil chamber 29 does not flow into the anti-rod-side oil chamber 30 by the check valve 31 provided in the piston 27, so the piston speed is relatively slow. In this case, the fluid flows from the orifice 35 provided in the inner cylinder 3 to the reservoir chamber 6 via the annular groove 36 and the ejection pipe 38, and an expansion-side damping force is generated. Subsequently, when the piston speed increases and the fluid pressure in the rod side oil chamber 29 of the inner cylinder 3 becomes larger than the urging force of the spring 48, the hydraulic oil in the rod side oil chamber 29 flows into the second flow path of the communication flow path 40. The pressure regulating valve 45 provided in the valve 42 is opened and flows into the reservoir chamber 6, and an expansion-side damping force is generated accordingly. During the extension stroke, the hydraulic oil corresponding to the retraction of the piston rod 28 is supplied from the reservoir chamber 6 to the anti-rod side oil chamber 30 via the check valve 32 provided in the rear columnar member 26 of the rear cover 5. The

  On the other hand, during the contraction stroke of the piston rod 28, the hydraulic oil in the anti-rod side oil chamber 30 flows into the rod side oil chamber 29 via the check valve 31 provided in the piston 27, and the anti-rod side oil chamber 30 and the rod side When the fluid pressure in the oil chamber 29 is substantially the same and the piston speed is relatively slow, the hydraulic oil that has entered the piston rod 28 passes through the annular groove 36 and the ejection pipe 38 from the orifice 35 provided in the inner cylinder 3. Then, it flows into the reservoir chamber 6 and a contraction-side damping force is generated. Subsequently, when the piston speed increases and the fluid pressure in the inner cylinder 3 becomes larger than the biasing force of the spring 48, the hydraulic oil that has entered the piston rod 28 is provided in the second flow path 42 of the communication flow path 40. The pressure regulating valve 45 is opened to flow into the reservoir chamber 6, and a contraction-side damping force is generated accordingly.

Further, during the expansion stroke and contraction stroke of the piston rod 28, the air accumulated at the front upper end of the rod side oil chamber 29 together with the working oil passes from the orifice 35 provided in the inner cylinder 3 through the annular groove 36 and the ejection pipe 38 to the reservoir chamber. 6 is discharged.
Further, during the expansion stroke and contraction stroke of the piston rod 28, the pressure difference between the pressure P2 in the buffering annular groove 37 and the pressure P3 in the reservoir chamber 6 becomes small, so that the outer peripheral surface of the inner cylinder 3 and the front cylindrical member The hydraulic oil is prevented from being ejected from the space between the inner peripheral surface of the 14 sub-cylindrical portions 16.

As described above, in the fluid pressure shock absorber 1a according to the first embodiment of the present invention, the orifice 35 provided in the inner cylinder 3 on the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 in particular. An annular groove portion 36 is formed as an annular passage communicating with the annular groove portion, and a buffering annular groove portion 37 is formed on the opening end side of the sub-cylindrical portion 16 of the front tubular member 14 from the annular groove portion 36. The passage sectional area of the annular groove 36 is set larger than the passage sectional area of the buffering annular groove 37.
As a result, in the conventional oil damper (oil damper according to Patent Document 1), the pressure P1 in the annular passage is considerably larger than the pressure P3 in the reservoir chamber 6 and the pressure difference causes the outer peripheral surface and the front side of the inner cylinder 3 to move forward. Although there was a concern that hydraulic oil may be ejected from between the inner peripheral surface of the sub-cylindrical portion 16 of the cylindrical member 14 and aeration may occur, in this embodiment, the pressure P2 in the buffering annular groove portion 37 and The pressure difference with the pressure P3 in the reservoir chamber 6 can be made smaller than the pressure difference between the pressure P1 in the conventional annular passage and the pressure P3 in the reservoir chamber 6, and the outer peripheral surface of the inner cylinder 3 and the front side It became possible to suppress the ejection of hydraulic oil from between the inner peripheral surface of the sub-cylindrical portion 16 of the cylindrical member 14.

  Further, in the fluid pressure shock absorber 1a according to the first embodiment, a time delay can be generated until the pressure P1 of the annular groove portion 36 increases substantially equal to the pressure P2 of the buffer annular groove portion 37. The ejection of hydraulic oil from between the outer peripheral surface of the inner cylinder 3 and the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 can be suppressed. In short, since the vibration waveform applied to the fluid pressure shock absorber 1a is often a sine wave or a waveform similar thereto, this time delay leads to suppression of the ejection of hydraulic oil.

Furthermore, in the fluid pressure shock absorber 1a according to the first embodiment, the number of parts such as an O-ring can be reduced as compared with the conventional oil damper (oil damper according to Patent Document 1), and the assembly man-hour can be further reduced. As a result, cost increases can be suppressed.
Moreover, in the conventional oil damper (oil damper according to Patent Document 1), seal members that seal between the inner peripheral surface of the concave portion of the front lid and the outer peripheral surface of the inner cylinder are respectively provided on both axial sides of the annular passage. Since the area surrounding the annular passage is completely sealed, when the piston speed increases and the flow rate flowing from the inner cylinder 3 to the reservoir increases, the flow rate of the hydraulic oil is However, in the fluid pressure shock absorber 1a according to the first embodiment, the rear side of the annular groove 36 (the sub-cylinder shape of the front side cylindrical member 14) has occurred. Since only the buffering annular groove 37 is formed on the opening end side of the portion 16 and the area surrounding the annular groove 36 is not completely sealed, the piston speed is increased and the reservoir chamber 6 from the inner cylinder 3 is increased. Even if the flow rate of hydraulic fluid flowing to It is possible to prevent the back pressure is applied to the valve 45.
In the first embodiment, the configuration in which the hydraulic oil in the inner cylinder 3 is guided to the annular groove 36 by the orifice 35 is shown. However, instead of the orifice 35, the first flow path 41 and the first flow path 41 are provided. Another set of the second flow path 42 that communicates and extends in the radial direction, and the third flow path 43 that communicates with the second flow path 42 and communicates with the lower portion of the annular groove 36 and extends in the axial direction, and the pressure regulating valve 45. The pressure regulating valve may be configured to have a valve opening pressure lower than that of the pressure regulating valve 45. In that case, the pressure regulating valve is first opened, and then the pressure regulating valve 45 is opened. Even in this case, it is possible to suppress the ejection of hydraulic oil from between the outer peripheral surface of the inner cylinder 3 and the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14.

Next, the fluid pressure shock absorber 1b according to the second embodiment will be described with reference to FIG. 3, but the description is limited to only the differences from the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1b according to the second embodiment, a plurality of buffering annular groove portions 37 are provided along the axial direction on the inner peripheral surface of the sub tubular portion 16 of the front tubular member 14. For example, in the present embodiment, two buffering groove portions 37 are formed.

Next, the fluid pressure shock absorber 1c according to the third embodiment will be described with reference to FIG. 4, but the description is limited to the difference from the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1c according to the third embodiment, a communication path that communicates the lower portion of the buffer annular groove portion 37 and the lower portion of the reservoir chamber 6 to the lower portion of the sub-cylindrical portion 16 of the front cylindrical member 14. The orifice 60 is provided. The orifice 60 extends in the axial direction. The passage sectional area of the orifice 60 is set smaller than the passage sectional area of the buffering annular groove portion 37.

Next, the fluid pressure shock absorber 1d according to the fourth embodiment will be described with reference to FIG. 5, but the description will be made only on the differences from the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1d according to the fourth embodiment, the lower end portion of the buffer annular groove portion 37, the inside of the ejection pipe 38, the lower portion of the sub-cylindrical portion 16 of the front side tubular member 14 and the upper peripheral wall of the ejection pipe 38 are provided. The orifice 61 is continuously provided as a communication path that communicates with each other. The orifice 61 extends in the radial direction. The passage sectional area of the orifice 61 is set smaller than the passage sectional area of the buffering annular groove portion 37.
And the fluid pressure buffer 1b-1d which concerns on 2nd-4th embodiment has an effect equivalent to the fluid pressure buffer 1a which concerns on 1st Embodiment.

Next, the fluid pressure shock absorber 1e according to the fifth embodiment will be described with reference to FIG. 6. However, the description is limited to only the differences from the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1e according to the fifth embodiment, an annular gap 63 is provided between the outer peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 and the inner peripheral surface of the outer cylinder 2, and the annular groove portion 36 is provided. An orifice 65 that communicates the lower end portion with the lower end portion of the annular gap 63 is provided. The orifice 65 extends in the radial direction. Note that the fluid pressure shock absorber 1e according to the fifth embodiment does not include the buffering annular groove portion 37 provided in the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1e according to the fifth embodiment, when the piston speed increases and the pressure P1 of the annular groove 36 increases, the hydraulic oil mainly passes from the annular groove 36 through the ejection pipe 38 and reaches the lower reservoir chamber. 6 flows out into the hydraulic oil 6, but the lower reservoir chamber passes through the annular gap 63 between the outer peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 and the inner peripheral surface of the outer cylinder 2 from the orifice 65. 6 flows out into the hydraulic fluid. As a result, it is possible to suppress the ejection of hydraulic oil from between the outer peripheral surface of the inner cylinder 3 and the inner peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14.

Next, although the fluid pressure shock absorber 1f according to the sixth embodiment will be described with reference to FIG. 7, the description is limited to only the differences from the fluid pressure shock absorber 1a according to the first embodiment. In addition, the fluid pressure shock absorber 1f according to the sixth embodiment is effective when used vertically so that the bracket 10 integrally connected to the tip of the piston rod 28 faces upward.
That is, in the fluid pressure shock absorber 1f according to the sixth embodiment, an orifice 67 is formed which communicates with a position of the bottom of the annular groove 36 where the pressure regulating valve 45 is provided in plan view. The orifice 67 extends in the radial direction. Further, the orifice 67 communicates with an outer peripheral annular groove portion 68 provided on the outer peripheral surface of the sub cylindrical portion 16 of the front side cylindrical member 14. The outer circumferential annular groove 68 has a rectangular cross section. The outer peripheral annular groove portion 68 communicates with an annular gap 63 between the outer peripheral surface of the sub-cylindrical portion 16 of the front cylindrical member 14 and the inner peripheral surface of the outer cylinder 2. The passage sectional area of the outer peripheral groove portion 68 is set smaller than the passage sectional area of the annular groove portion 36. Note that the fluid pressure shock absorber 1f according to the sixth embodiment does not include the buffering annular groove portion 37 provided in the fluid pressure shock absorber 1a according to the first embodiment.
In the fluid pressure shock absorber 1f according to the sixth embodiment, when the pressure P1 of the annular groove 36 is increased, the hydraulic oil enters the hydraulic oil in the reservoir chamber 6 mainly from the annular groove 36 via the ejection pipe 38. leak. At the same time, the hydraulic oil collides with the inner peripheral surface of the outer cylinder 2 from the orifice 67 via the outer peripheral annular groove portion 68 and the annular clearance 63, and the ejection force is relieved by the outer peripheral annular groove portion 68. And dripping into the reservoir chamber 6. As a result, aeration can be suppressed.

  In addition, although this embodiment is employ | adopted as the uniflow type damper, you may employ | adopt as a biflow type damper. In addition, the present embodiment is proposed to suppress aeration due to the ejection of hydraulic oil from the fitting portion between the inner cylinder 3 and the sub-cylindrical portion 16 of the front cylindrical member 14. This also has the effect of suppressing air entrainment in the fitting portion when the hydraulic oil is sucked in the biflow damper.

  1a to 1f Fluid pressure buffer, 2 outer cylinder, 3 inner cylinder, 4 front lid body, 5 rear lid body, 6 reservoir chamber, 14 front cylindrical member, 16 sub cylindrical section (cylindrical section), 29 rod Side liquid chamber (liquid chamber), 30 Anti-rod side liquid chamber, 35 Orifice (damping force generating orifice), 36 Annular groove (annular passage), 37 Buffer annular groove (annular space), 38 Ejection pipe (pipe), 60 Orifice (communication path), 61 Orifice (communication path)

Claims (3)

The outer cylinder and the inner cylinder respectively arranged concentrically are closed at both ends with a lid, and are configured as an annular reservoir chamber in which hydraulic fluid and gas are sealed between the two, and at least one end of the inner cylinder And a fluid pressure shock absorber provided with an annular passage extending in the radial direction and an orifice for generating a damping force in a fitting portion between the cylindrical portion provided in the lid body,
The annular passage communicates with the liquid chamber in the inner cylinder via the damping force generating orifice, and is closer to the opening end side of the tubular portion than the annular passage. A fluid pressure buffer characterized by forming a small annular space.   2. The fluid pressure buffer according to claim 1, wherein the fluid pressure buffer is disposed horizontally, and includes a pipe having one side communicating with the annular passage and the other side extending into the working fluid of the reservoir chamber. vessel.   3. The fluid pressure shock absorber according to claim 1, wherein the annular space communicates with the reservoir chamber through a communication passage, and the communication passage has a cross-sectional area smaller than a cross-sectional area of the annular space.

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