WO2022097378A1

WO2022097378A1 - Shock absorber

Info

Publication number: WO2022097378A1
Application number: PCT/JP2021/034293
Authority: WO
Inventors: 和晶柴原
Original assignee: 日立Astemo株式会社
Priority date: 2020-11-05
Filing date: 2021-09-17
Publication date: 2022-05-12
Also published as: JPWO2022097378A1; JP7438394B2

Abstract

According to the present invention, a first chamber and a reservoir (reservoir chamber) which are inside a tube are made to communicate with each other by means of a recess section formed on an annular plate on a right end surface, which is a tube-facing surface, and therefore the flow path cross-sectional area of a path defined by the recess section is not affected by the plate thickness of the annular plate. In addition, since the recess section is formed by coining (pressure imprinting), the recess section can be formed with extremely high accuracy. Thus, it is possible to suppress a variation in air venting performance and damping force characteristics between products, and the reliability of this shock absorber can be improved.

Description

Shock absorber

The present invention relates to a double-cylinder hydraulic shock absorber used in railway vehicles and the like.

Patent Document 1 discloses a double-cylinder shock absorber in which an orifice functioning as a damping force generating element and an air bleeding element is formed by a notch provided in an annular plate interposed between a cylinder and a rod guide. ing.

Japanese Unexamined Patent Publication No. 2012-233595

By the way, in the shock absorber disclosed in Patent Document 1 (hereinafter referred to as "conventional shock absorber"), the annular plate is provided with a notch (orifice) having an extremely small flow path area (for example, "0.3 mm" in terms of hole diameter). Need to form. Therefore, a thin plate (for example, a plate thickness "0.3 mm") is used for the annular plate. In this case, if the tolerance of the plate thickness of the thin plate is not strictly controlled, the flow path area of the notch (orifice) will vary due to the influence of the tolerance of the plate thickness of the thin plate, and eventually the air bleeding performance between products. (Damping force characteristics) may vary and reliability may decrease.

An object of the present invention is to provide a double-cylinder hydraulic shock absorber with improved reliability.

The shock absorber according to the embodiment of the present invention is provided between the cylinder, the tube provided on the inner peripheral side of the cylinder and in which the working fluid is sealed, and the cylinder and the tube, and is provided between the cylinder and the gas. A reservoir chamber in which a gas is sealed, a piston slidably provided in the tube, and a piston that divides the inside of the tube into two chambers, one end of which is connected to the piston, and the other end of which extends to the outside of the cylinder. A piston rod, a closing member provided at the end of the tube and closing the cylinder and the tube, and a closing member provided between the closing member and the end of the tube and fitted to the closing member. An annular plate is provided, and a recess for communicating the tube and the reservoir chamber is formed on the surface of the annular plate facing the tube.

According to one embodiment of the present invention, the reliability of the double-cylinder hydraulic shock absorber can be improved.

It is sectional drawing in the shock absorber of 1st Embodiment. It is a figure which shows the main part in FIG. 1 in an enlarged manner. It is a perspective view of the annular plate in the shock absorber of 1st Embodiment. It is sectional drawing which shows the main part in the shock absorber of 2nd Embodiment by enlargement. FIG. 4 is an arrow view taken along the line AA in FIG. It is sectional drawing which shows the main part in the shock absorber of 3rd Embodiment enlarged. FIG. 6 is a view taken along the line BB in FIG. It is sectional drawing which shows the main part in the shock absorber of 4th Embodiment enlarged. FIG. 8 is a view taken along the line CC in FIG. It is a figure which shows the main part in the shock absorber of the 5th Embodiment in an enlarged manner. It is a perspective view of the annular plate in the shock absorber of 5th Embodiment. It is a perspective view of the annular plate for showing the modification of the concave part. It is a perspective view of the annular plate for showing the modification of the concave part. It is a perspective view of the annular plate for showing the modification of the concave part. It is a perspective view of the annular plate for showing the modification of the concave part.

(First Embodiment) This will be described with reference to the figure attached to the first embodiment of the present invention.
Here, a double-cylinder horizontal hydraulic shock absorber 1 (hereinafter referred to as “buffer 1”), which is arranged substantially horizontally as a left-right moving damper between the vehicle body of a railway vehicle and a bogie, will be described. In the following description, for convenience, the vertical direction and the horizontal direction in FIG. 1 are referred to as the vertical direction and the horizontal direction as they are, but it is not intended to limit the mounting direction (direction) of the shock absorber 1.

As shown in FIG. 1, the shock absorber 1 has a cylinder 2 and a tube 3 provided on the inner peripheral side of the cylinder 2. The left end of the cylinder 2 and the tube 3 is closed by the rod guide 41 (blocking member). On the other hand, the right end of the cylinder 2 and the tube 3 is closed by the end plate 5. An annular reservoir 4 (reservoir chamber) is formed between the cylinder 2 and the tube 3. The end plate 5 is divided into an end plate 6 that closes the right end of the cylinder 2 and an end plate 7 that closes the right end of the tube 3. A bracket 8 connected to the vehicle body side of the railway vehicle is fixed to the end plate 6. The end plate 6 and the end plate 7 are integrated by fitting the shaft portion 9 formed at the right end of the end plate 7 into the recess 10 formed at the left end of the end plate 6.

The piston 12 is slidably fitted in the tube 3. The piston 12 divides the inside of the tube 3 into a first chamber 13 on the rod guide 41 side and a second chamber 14 on the end plate 5 side. The first chamber 13 and the second chamber 14 are filled with the hydraulic fluid, and the reservoir 4 is filled with the hydraulic fluid and air (gas). The right end (one end) of the piston rod 15 is connected to the piston 12. The left end side (the other end side) of the piston rod 15 extends to the outside of the tube 3 through the first chamber 13 and the rod guide 41. A bracket 16 connected to the bogie side of a railroad vehicle is fixed to the left end of the piston rod 15. A tubular cover 17 that covers the exposed portion of the piston rod 15 is attached to the bracket 16.

The piston 12 prevents the movement of the hydraulic fluid from the second chamber 14 to the first chamber 13 during the contraction stroke of the piston rod 15, and opens the valve when the hydraulic pressure of the second chamber 14 reaches a constant pressure. By doing so, a relief valve 18 is provided to release the hydraulic pressure of the second chamber 14 to the first chamber 13. Further, when the hydraulic fluid in the first chamber 13 reaches a constant pressure by blocking the movement of the hydraulic fluid from the first chamber 13 to the second chamber 14 during the extension stroke of the piston rod 15 on the piston 12. By opening the valve, a relief valve 19 is provided to release the hydraulic pressure of the first chamber 13 to the second chamber 14. On the other hand, the end plate 7 is provided with a relief valve 20 that opens when the hydraulic pressure of the second chamber 14 reaches a set pressure and releases the hydraulic pressure of the second chamber 14 to the reservoir 4. Further, the end plate 7 is provided with a check valve 21 (check valve) that allows the flow of the hydraulic fluid from the reservoir 4 to the second chamber 14.

A cylindrical portion 22 having an opening on the left end is formed on the outer peripheral edge of the end plate 7. The right end portion 23 of the tube 3 is fitted inside the cylindrical portion 22. The right end portion 23 of the tube 3 and the cylindrical portion 22 of the end plate 7 are sealed by a seal ring 25. The tube 3 is positioned in the left-right direction (axial direction) by the end surface 24 of the right end portion 23 being abutted against the bottom portion of the cylindrical portion 22 of the end plate 7. On the other hand, the left end portion 26 of the tube 3 is liquidt tightly fitted to the concave tube fitting portion 43 provided on the right end surface 42 of the rod guide 41.

The outer peripheral surface 44 of the rod guide 41 is fitted to the rod guide fitting portion 37 formed on the inner peripheral surface 36 of the left end portion 35 of the cylinder 2. A lock ring 29 is screwed into the opening of the left end portion 35 of the cylinder 2. By tightening the lock ring 29, an axial force is applied to the tube 3 pressurized between the rod guide 41 and the end plate 7. The shaft hole 30 of the lock ring 29 is provided with an oil seal 31 that is in sliding contact with the piston rod 15. On the other hand, the shaft hole 47 of the rod guide 41 is provided with a seal ring 32 that is in sliding contact with the piston rod 15.

An annular groove 49 is formed in the vicinity of the bottom 48 of the tube fitting portion 43 of the rod guide 41. In the first embodiment, the annular groove 49 forms an endless annular circle extending in the circumferential direction of the tube fitting portion 43, and for example, a state in which the shock absorber 1 is attached to a railway vehicle (hereinafter, “attachment of the shock absorber 1”). In the state (referred to as "state"), it can be an ended annular semicircle extending from the upper end portion to the lower end portion of the tube fitting portion 43.

As shown in FIG. 2, a small outer diameter portion 45 having a smaller diameter with respect to the outer peripheral surface 44 is formed on the right end portion of the rod guide 41, in other words, on the outer periphery of the tube fitting portion 43. As a result, an annular gap 46 communicating with the reservoir 4 is formed between the small outer diameter portion 45 of the rod guide 41 and the inner peripheral surface 36 of the cylinder 2. The annular gap 46 has a constant flow path area provided at the lower end of the small outer diameter portion 45 of the rod guide 41 (at the position of “6 o'clock” in the clock position) when the shock absorber 1 is attached. The passage 50 having the rod guide 41 communicates with the annular groove 49 formed in the tube fitting portion 43 of the rod guide 41.

An annular plate 53 (see FIG. 3) is interposed between the bottom 48 of the tube fitting portion 43 of the rod guide 41 and the end surface 27 of the left end portion 26 of the tube 3. The annular plate 53 has a rectangular (channel shape) cross section formed by a plane perpendicular to the axis of the shock absorber 1 (hereinafter referred to as “axis right angle plane”). A part of the outer peripheral surface 54 (see FIG. 3) of the annular plate 53 is a portion on the left side of the annular groove 49 in the tube fitting portion 43, in other words, an annular shape formed between the annular groove 49 and the bottom portion 48. It is fitted to the cylindrical surface of the plate fitting portion 51 with a constant fitting tolerance. The inner diameter of the annular plate 53 is smaller than the inner diameter of the left end portion 26 of the tube 3.

The height of the plate fitting portion 51 of the rod guide 41, in other words, the distance in the left-right direction from the bottom 48 of the tube fitting portion 43 of the rod guide 41 to the annular groove 49 is the plate thickness (left-right direction) of the annular plate 53. Is shorter than the length of). That is, the right end of the outer peripheral surface 54 of the annular plate 53 faces the annular groove 49 of the rod guide 41. The left end surface 56 of the annular plate 53 is in contact with the bottom 48 of the tube fitting portion 43 of the rod guide 41. On the other hand, the end surface 27 of the left end portion 26 of the tube 3 is in contact with the right end surface 57 of the annular plate 53.

Referring to FIGS. 2 and 3, a recess 81 is formed in the right end surface 57 of the annular plate 53 facing the tube 3. The recess 81 extends in the radial direction of the annular plate 53 from the outer peripheral surface 54 of the annular plate 53 to the inner peripheral surface 55 (see FIG. 3). The recess 81 extends in the vertical direction at the upper end portion (position at the time of “12” in the clock position) of the annular plate 53 in the mounted state of the shock absorber 1. The concave portion 81 is formed into a rectangular cross section (channel shape) by coining (printing pressure processing). The recess 81 communicates the annular passage 52 defined by the annular groove 49 of the rod guide 41 with the first chamber 13 in the tube 3. The recess 81 can be processed by engraving, etching, or the like in addition to coining.

The shock absorber 1 is configured to have an air bleeding structure for discharging the air accumulated in the first chamber 13 to the reservoir 4. In the air bleeding structure configured in the shock absorber 1 of the first embodiment, the air accumulated in the corners of the first chamber 13 reaches the recess 81, the annular passage 52, the passage 50, and the annular gap during the extension stroke of the piston rod 15. It is discharged to the reservoir 4 via 46. On the other hand, the recess 81 functions as an orifice that generates a damping force with respect to the flow of the hydraulic fluid flowing from the first chamber 13 to the reservoir 4 through the recess 81, the annular passage 52, the passage 50, and the annular gap 46.

The operation of the first embodiment will be described.
The piston rod 15 of the shock absorber 1 arranged sideways expands and contracts as the vehicle body of the railroad vehicle and the bogie move relative to each other in the horizontal direction. During the extension stroke of the piston rod 15, the hydraulic fluid in the first chamber 13 flows to the second chamber 14 through the relief valve 19 of the piston 12. In parallel with this, the hydraulic fluid in the first chamber 13 flows to the reservoir 4 through the recess 81 of the annular plate 53, the annular passage 52, the passage 50 of the rod guide 41, and the annular gap 46. At this time, the hydraulic fluid in the first chamber 13 flows through the relief valve 18 and the recess 81 (orifice), so that a damping force on the extension side is generated.

Further, in the extension stroke of the piston rod 15, the air accumulated in the corner portion of the first chamber 13 is contained in the hydraulic fluid as bubbles (aerobic hydraulic fluid), and the annular plate 53 is formed from the first chamber 13. It is discharged to the reservoir 4 through the recess 81, the annular passage 52, the passage 50 of the rod guide 41, and the annular gap 46. During the extension stroke of the piston rod 15, the hydraulic fluid corresponding to the volume of the piston rod 15 exiting from the first chamber 13 opens the check valve 21 of the end plate 7 from the reservoir 4 to the second chamber 14. be introduced.

On the other hand, during the contraction stroke of the piston rod 15, the hydraulic fluid in the second chamber 14 passes through the relief valve 18 of the piston 12 and flows to the first chamber 13. In parallel with this, the hydraulic fluid corresponding to the volume of the piston rod 15 entering the first chamber 13 is discharged from the second chamber 14 to the reservoir 4 via the relief valve 20 of the end plate 7. At this time, the hydraulic fluid in the second chamber 14 flows through the relief valve 18 and the relief valve 20, so that a damping force on the contraction side is generated.

Here, in the conventional shock absorber, it is necessary to form a notch (orifice) having an extremely small flow path area (for example, “0.3 mm” in terms of hole diameter) in the annular plate, so that the annular plate is a thin plate (for example, plate thickness). "0.3 mm") is used. However, if the tolerance of the plate thickness of the thin plate is not strictly controlled, the flow path area of the notch (orifice) will vary due to the influence of the tolerance of the plate thickness of the thin plate, and eventually the air bleeding performance (air bleeding performance between products). The damping force characteristics) will vary, and the reliability of the shock absorber will decrease.
Further, when a thin plate is used as the annular plate, the crushing allowance cannot be secured. Therefore, the end plate is only slightly tilted due to welding accuracy or the like, and a gap is generated at the contact portion between the annular plate and the tube. The hydraulic fluid (pressure) of the first chamber 13 may leak to the reservoir 4 side through the gap.
In addition, when a thin plate is used as the annular plate, the crushing allowance cannot be secured, so that the slight inclination of the end plate cannot be absorbed by the crushing allowance, and the axial force acting on the tube is deflected to lock. The ring may loosen.
Further, in the conventional shock absorber, since the plate thickness of the annular plate affects the flow path area of the orifice, the damping force of the orifice characteristic varies depending on the tolerance of the plate thickness.
Further, in the conventional shock absorber, the notch is processed by pressing the thin plate, so that the burr generated in the notch may reduce the contamination dischargeability.
Further, in the conventional shock absorber, since the end of the notch receives the jet of the hydraulic fluid, aeration may occur and the end of the notch may be worn.

On the other hand, in the first embodiment, the concave portion 81 is formed in the right end surface 57 of the annular plate 53 facing the tube 3, and the concave portion 81 forms the first chamber 13 and the reservoir 4 in the tube 3. Since the (reservoir chamber) is communicated with the (reservoir chamber), the cross-sectional area of the recess 81 and the flow path area of the passage defined by the recess 81 are not affected by the plate thickness of the annular plate 53. In addition, since the concave portion 81 is formed by coining (printing pressure processing), the concave portion 81 can be formed with extremely high accuracy.
As a result, it is possible to suppress variations in air bleeding performance between products, and it is possible to improve the reliability of the shock absorber 1.
Further, since the shape of the recess 81 and the flow path area of the orifice formed by the recess 81 are not affected by the plate thickness of the annular plate 53, it is possible to suppress variations in damping force characteristics between products. It is possible and the reliability of the shock absorber 1 can be improved.
Further, since the thickness of the annular plate 53 and the crushing allowance of the annular plate 53 are secured, it is possible to prevent the leakage of the hydraulic fluid through the contact portion between the annular plate and the tube. Further, since the inclination of the end plate 5 is absorbed by the crushing allowance, the axial force acting on the tube 3 can be made uniform in the circumferential direction, and the lock ring 29 can be suppressed from loosening.
Further, in the first embodiment, since the recess 81 is formed by coining (printing pressure processing), no burrs are generated in the recess 81, and contamination in the hydraulic fluid is transmitted from the first chamber 13 through the recess 81. It can be smoothly discharged to the reservoir 4. Further, since the flow path area of the orifice can be set finely, it is possible to provide the shock absorber 1 having improved tuning property of the damping force characteristic.
Further, in the first embodiment, since the concave portion 81 extends from the inner peripheral surface 55 (inner peripheral side end surface) of the annular plate 53 to the outer peripheral surface 54 (outer peripheral side end surface), the direction of the flow of the hydraulic fluid flowing through the concave portion 81 ( There is no barrier that hinders the radial direction), and wear of the annular plate 53 can be suppressed.

(Second Embodiment) Next, the second embodiment will be described with reference to FIGS. 4 to 5.
For the parts common to the first embodiment, the same names and reference numerals will be used, and duplicate description will be omitted. Here, the difference from the first embodiment will be mainly described.

In the first embodiment, the left end portion 26 of the tube 3 is fitted into the concave tube fitting portion 43 provided on the right end surface 42 of the rod guide 41, and the tube 3 is connected to the rod guide 41.

On the other hand, in the second embodiment, the convex tube fitting portion 61 provided on the right end surface 42 of the rod guide 41 is fitted into the inside (inner peripheral surface) of the left end portion 26 of the tube. The tube 3 was coupled to the rod guide 41. The tube fitting portion 61 has an outer peripheral surface 62 formed of a cylindrical surface coaxial with the axis of the shock absorber 1. An annular groove 49 is provided on the outer peripheral surface 62. The annular groove 49 is formed in the vicinity of the right end surface 42 of the rod guide 41. The outer peripheral surface 62 is provided with a groove 63 extending in the left-right direction (axial direction) from the upper end portion (position at “12 o'clock” in the clock position) of the tube fitting portion 61 in the mounted state of the shock absorber 1.

In the annular plate 53, the base portion of the tube fitting portion 61 (the portion on the left side of the annular groove 49) is fitted to a part of the inner peripheral surface 55 (see FIG. 5), and the left end surface 56 is on the right side of the rod guide 41. It comes into contact with the end face 42. The annular plate 53 has an outer diameter larger than the outer diameter of the tube 3. A recess 81 is formed in the right end surface 57 of the annular plate 53 facing the tube 3. The recess 81 extends in the vertical direction at the lower end of the annular plate 53 (at the “6 o'clock” position in the clock position) with the shock absorber 1 attached. The recess 81 communicates the annular passage 52 defined by the annular groove 49 of the rod guide 41 with the first chamber 13 in the tube 3.

In the air bleeding structure of the shock absorber 1 of the second embodiment, the air accumulated in the corner portion of the first chamber 13 is the groove 63 of the outer peripheral surface 62 of the tube fitting portion 61 and the annular passage during the extension stroke of the piston rod 15. It is discharged to the reservoir 4 through 52 and the recess 81. On the other hand, the recess 81 functions as an orifice that generates a damping force with respect to the flow of the hydraulic fluid flowing from the first chamber 13 through the groove 63, the annular passage 52, and the recess 81 to the reservoir 4.

According to the second embodiment, it is possible to obtain the same effect as that of the first embodiment described above.
Further, in the second embodiment, when the guide lengths of the rod guides 41 are the same as those of the first embodiment, the rod guides 41 have a length corresponding to the axial length of the tube fitting portion 61. The total length (length in the axial direction), and thus the total length of the shock absorber 1, can be shortened, and the shock absorber 1 can be miniaturized.

(Third Embodiment) Next, the third embodiment will be described with reference to FIGS. 6 to 7.
For the parts common to the first and second embodiments, the same names and reference numerals are used, and duplicate explanations will be omitted. Here, the difference from the second embodiment will be mainly described.

In the second embodiment, it is necessary to assemble the annular plate 53 so that the recess 81 is located at the lower end portion (the position of "6 o'clock" in the clock position) in the mounted state of the shock absorber 1. Therefore, in the third embodiment, a positioning mechanism 65 for positioning the annular plate 53 around the axis with respect to the rod guide 41 is provided.

The positioning mechanism 65 includes a groove 66 provided at the upper end of the tube fitting portion 61 of the rod guide 41 (at the “12 o'clock” position in the clock position) and the inside of the annular plate 53 when the shock absorber 1 is attached. It has a convex portion 67 that protrudes radially from the peripheral surface 55 and is fitted into the groove 66. The groove 66 extends from the end surface 64 of the tube fitting portion 61 to the right end surface 42 of the rod guide 41, and the cross section in the plane perpendicular to the axis is formed in a rectangular shape (channel shape). On the other hand, the convex portion 67 has a rectangular cross section formed by a plane perpendicular to the axis, and is provided on the opposite side of the concave portion 81 (upper end portion when the shock absorber 1 is attached) via the center of the annular plate 53. The positioning mechanism 65 is configured such that the convex portion 67 of the annular plate 53 is fitted into the groove 66 with a constant gap in the vertical direction and the horizontal direction in FIG. 7.

In the third embodiment, it is possible to obtain the same effect as that of the first to second embodiments described above.
Further, in the third embodiment, since the annular plate 53 is positioned around the axis with respect to the rod guide 41 by the positioning mechanism 65, the recess 81 is surely placed under the annular plate 53 in the mounted state of the shock absorber 1. It can be placed at the side end. As a result, malfunction due to improper assembly of the annular plate 53 is suppressed, and the reliability of the shock absorber 1 can be improved.

(Fourth Embodiment) Next, the fourth embodiment will be described with reference to FIGS. 8 to 9.
For the parts common to the first to third embodiments, the same names and reference numerals are used, and duplicate explanations will be omitted. Here, the difference from the first embodiment will be mainly described.

In the first embodiment, it is necessary to assemble the annular plate 53 so that the recess 81 is located at the upper end (the position of "12 o'clock" in the clock position) in the mounted state of the shock absorber 1. Therefore, in the fourth embodiment, a positioning mechanism 71 for positioning the annular plate 53 around the axis with respect to the rod guide 41 is provided.

An annular convex portion 72 having a constant height is provided on the inner peripheral edge portion of the bottom portion 48 of the tube fitting portion 43 of the rod guide 41. An annular plate 53 is provided on the outer periphery of the annular convex portion 72. A certain gap is formed between the outer peripheral surface 73 of the annular convex portion 72 and the inner peripheral surface 55 of the annular plate 53. The height of the annular convex portion 72 (the amount of protrusion from the bottom portion 48) is set to, for example, the plate thickness of the annular plate 53.

The positioning mechanism 71 has a groove 75 provided at the upper end of the annular convex portion 72 of the rod guide 41 (at the “12 o'clock” position in the clock position) and the inner circumference of the annular plate 53 when the shock absorber 1 is attached. It has a convex portion 67 that protrudes radially from the surface 55 and is fitted into the groove 75. The groove 75 extends from the end surface 74 of the annular convex portion 72 to the bottom portion 48 of the tube fitting portion 43, and a rectangular cross section formed by a plane perpendicular to the axis is formed. On the other hand, the convex portion 67 has a rectangular cross section formed by a plane perpendicular to the axis, and is provided at the upper end portion in the mounted state of the shock absorber 1. The positioning mechanism 71 is configured such that the convex portion 67 of the annular plate 53 is fitted into the groove 75 with a certain gap in the vertical direction and the horizontal direction in FIG. The concave portion 81 extends from the outer peripheral surface 54 of the annular plate 53 to the end surface 68 of the convex portion 67.

In the fourth embodiment, it is possible to obtain the same effect as that of the first to third embodiments described above.
Further, in the fourth embodiment, since the annular plate 53 is positioned around the axis with respect to the rod guide 41 by the positioning mechanism 71, the recess 81 is surely positioned at the upper end of the annular plate 53 in the mounted state of the shock absorber 1. Can be placed in the department. As a result, malfunction due to improper assembly of the annular plate 53 is suppressed, and the reliability of the shock absorber 1 can be improved.

(Fifth Embodiment) Next, the fifth embodiment will be described with reference to FIGS. 10 to 11.
For the parts common to the first to fourth embodiments, the same names and reference numerals are used, and duplicate explanations will be omitted. Here, the difference from the second embodiment will be mainly described.

In the second embodiment, the double-cylinder type horizontal hydraulic shock absorber 1 in which the piston rod 15 expands and contracts in the horizontal direction is targeted. On the other hand, in the fifth embodiment, a double-cylinder vertical hydraulic shock absorber 1A (hereinafter referred to as “buffer 1A”) in which the piston rod 15 expands and contracts in the vertical direction is targeted.

Further, in the second embodiment, the number of recesses 81 formed in the lower end surface 57 of the annular plate 53 facing the tube 3 was one. On the other hand, in the fifth embodiment, a plurality of (“6” in the fifth embodiment) recesses 81 are formed on the lower end surface 57 of the annular plate 53. The plurality of recesses 81 are arranged at equal intervals (“60 ° around the axis” in the fifth embodiment) in the circumferential direction of the annular plate 53.

Here, unlike the recesses 81 in the second embodiment, the plurality of recesses 81 in the fifth embodiment do not function as orifices. The flow path area of each recess 81 of the plurality of recesses 81 in the fifth embodiment is smaller than the flow path area of the recess 81 in the second embodiment, which also has a function as an orifice, and has an influence on the damping force characteristics. It is set to almost none. As a result, in the fifth embodiment, the piston rod 15 expands and contracts, so that the aerobic hydraulic fluid containing the air staying in the tube 3 reaches the groove 63, the annular passage 52, and the annular passage 52 during the extension stroke of the piston rod 15. It is discharged to the reservoir 4 through the plurality of recesses 81.

According to the fifth embodiment, the air staying in the tube 3 of the double-cylinder vertical hydraulic shock absorber 1A is stored from the plurality of recesses 81 formed on the facing surface of the annular plate 53 with the tube 3. It can be discharged to 4.
Further, in the fifth embodiment, since the plurality of recesses 81 are formed (molded) by coining (printing pressure processing), it is possible to process a passage having an extremely small flow path area with high accuracy. As a result, the aeration hydraulic fluid in the tube 3 can be exuded to the reservoir 4 side through the passage having the minimum flow path area defined by the recess 81, and the hydraulic fluid in the tube 3 is recessed. Since it is not discharged as a jet from 81, it is possible to suppress the generation of aeration.

The above-described embodiment can be configured as follows.
In the first to fourth embodiments, the recess 81 has a constant cross-sectional shape from the outer peripheral surface 54 to the inner peripheral surface 55 of the annular plate 53.

On the other hand, the recess 81 shown in FIG. 12 is composed of a stationary portion 82 formed on the inner peripheral surface 55 side of the annular plate 53 and a widening portion 83 formed on the outer peripheral surface 54 side of the annular plate 53. Will be done. The stationary portion 82 extends radially from the inner peripheral surface 55 of the annular plate 53. On the other hand, the widening portion 83 is widened from the outer peripheral end of the stationary portion 82 toward the outer peripheral surface 54 (end surface) of the annular plate 53.
In this case, since the pressure (flow velocity) of the hydraulic fluid flowing through the stationary portion 82 is depressurized (decelerated) by the widening portion 83, the hydraulic fluid in the tube 3 is not discharged as a jet from the recess 81, and aeration is performed. Can be suppressed. Further, since the peripheral parts of the recess 81 do not receive the jet flow from the recess 81, it is possible to suppress the wear of the parts.

Further, the recess 81 shown in FIG. 13 is an inner peripheral side in which the stationary portion 82 in the recess 81 shown in FIG. 12 is widened from the connection portion 85 with the widening portion 83 toward the inner peripheral surface 55 of the annular plate 53. A widening portion 84 is provided. The flow path area (orifice area) in the connection portion 85 is set to be the same as the flow path area in the stationary portion 82 (see FIG. 12).
In this case, the opening width on the inner peripheral surface 54 side of the annular plate 53 in the recess 81 (inner peripheral widening portion 84), that is, the opening width on the first chamber 13 side is the opening of the stationary portion 82 (see FIG. 12). Since it is larger than the width, it is possible to improve the dischargeability of the air accumulated in the tube (3) and the contamination in the first chamber 13.

Further, in the recess 81 shown in FIG. 14, the bottom surface 86 of the widening portion 83 in the recess 81 shown in FIG. 12 is formed by a curved surface. The bottom surface 86 has a depth from the right end surface 57 of the annular plate 53, which is a surface facing the tube 3 (hereinafter referred to as “depth of the bottom surface 86”), toward the outer peripheral surface 54 (end surface) of the annular plate 53. Get deeper.
In this case, since the volume of the widening portion 83 increases with respect to the recess 81 shown in FIG. 12 where the depth of the bottom surface 86 is constant, the pressure of the flowing hydraulic fluid can be further reduced, and aeration can be performed. Can be suppressed more effectively.

On the other hand, the bottom surface 87 of the inner peripheral side widening portion 84 in the recess 81 shown in FIG. 13 can be formed by a curved surface. The depth of the bottom surface 87 from the right end surface 57 of the annular plate 53, which is the surface facing the tube 3 (hereinafter referred to as “the depth of the bottom surface 87”), faces the inner peripheral surface 55 (end surface) of the annular plate 53. And get deeper.
In this case, the dischargeability of the air accumulated in the tube (3) and the contamination in the first chamber 13 can be further improved.

Further, as shown in FIG. 15, the first recess 81A is provided on the right end surface 57 of the annular plate 53 facing the tube 3, and the second recess 81B is provided on the left end surface 56 which is the opposite surface. The shock absorber 1 can be provided.
In this case, by setting the flow path area in the first recess 81A and the flow path area in the second recess 81B to different areas, the characteristics of one annular plate 53 differ depending on the orientation (front and back) in which the annular plate 53 is assembled. (Air bleeding property, damping force characteristic) can be selected, and the tuning property of the shock absorber 1 can be improved.
On the other hand, by setting the flow path area in the first recess 81A and the flow path area in the second recess 81B to the same area, malfunction due to incorrect assembly direction (front and back) of the annular plate 53 is suppressed. Therefore, the reliability of the shock absorber 1 can be improved.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

This application claims priority based on Japanese Patent Application No. 2020-185208 filed on November 5, 2020. The entire disclosure, including the specification, claims, drawings, and abstracts of Japanese Patent Application No. 2020-185208 filed November 5, 2020, is incorporated herein by reference in its entirety.

1 shock absorber, 2 cylinder, 3 tube, 4 reservoir, 12 piston, 13 1st chamber, 14 2nd chamber, 15 piston rod, 41 rod guide (blocking member), 53 annular plate, 57 right end face (opposing to the tube) Surface), 81 concave

Claims

It is a shock absorber, and the shock absorber is
Cylinder and
A tube provided on the inner peripheral side of the cylinder and filled with a working fluid,
A reservoir chamber provided between the cylinder and the tube and in which the hydraulic fluid and the gas are sealed,
A piston that is slidably provided in the tube and divides the inside of the tube into two chambers,
A piston rod whose one end is connected to the piston and whose other end extends to the outside of the cylinder.
A closing member provided at the end of the tube and closing the cylinder and the tube,
It has an annular plate provided between the closing member and the end of the tube and fitted to the closing member.
A shock absorber characterized in that a recess for communicating the tube and the reservoir chamber is formed on the surface of the annular plate facing the tube.
In the shock absorber according to claim 1,
The recess is a shock absorber extending from the inner peripheral side end surface of the annular plate to the outer peripheral side end surface.
In the shock absorber according to claim 1 or 2.
A shock absorber characterized in that a plurality of the recesses are provided along the circumferential direction of the annular plate.
In the shock absorber according to any one of claims 1 to 3,
The recess is a shock absorber characterized in that the outer peripheral side of the annular plate is widened toward an end face.
In the shock absorber according to any one of claims 1 to 4.
The recess is a shock absorber characterized in that the outer peripheral side of the annular plate is formed so that the bottom becomes deeper toward the end face.
In the shock absorber according to any one of claims 1 to 5.
The recess is a shock absorber characterized in that the inner peripheral side of the annular plate is widened toward an end face.
In the shock absorber according to any one of claims 1 to 6.
The recess is a shock absorber characterized in that the inner peripheral side of the annular plate is formed so that the bottom becomes deeper toward the end face.
In the shock absorber according to any one of claims 1 to 7.
A shock absorber characterized in that a second recess is formed on the surface of the annular plate facing the closing member.