JP2006097880A - Hydraulic damper - Google Patents

Abstract

In a hydraulic damper that absorbs vibration, a pulling force applied to a fixing member is reduced without reducing vibration absorption capability.
A piston 12 integrated with a piston rod 14 and a free piston 13 are slidably disposed in a cylinder 11, and an oil liquid is sealed on both sides of the piston 12 and a gas is sealed on the bottom side of the free piston 13 respectively. To do. A low pressure relief valve 36 having an orifice 35 is disposed in an orifice passage 26 leading to an orifice port 23 provided at an intermediate position in the longitudinal direction of the cylinder 11, and the piston 12 is stroked from the stroke end side toward the neutral position. When the piston 12 is moving from the vicinity of the neutral position toward the stroke end side, the oil liquid flows through the orifice 35, and when the piston 12 is stroked toward the stroke end side, the relief passages 31 and 34 independent from the orifice passage 26 are used. A small damping force is generated by flowing the oil liquid.
[Selection] Figure 1

Description

  The present invention relates to a hydraulic damper for absorbing vibration of a structure such as an automobile suspension or a building.

This type of hydraulic damper generally includes a cylinder filled with oil, a piston slidably fitted in the cylinder, one end connected to the piston, and the other end to the outside of the cylinder. An extended piston rod, and a structure for generating a damping force by controlling the flow of oil produced by the stroke of the piston (see, for example, Patent Document 1). In addition, although it is a hydraulic damper for railcars, there is also a hydraulic damper that generates a large damping force near the stroke end away from the neutral position (for example, Patent Document 2).
Japanese Patent Laid-Open No. 52-113475 JP 2003-42216 A

By the way, the conventional general hydraulic damper has a structure that generates a damping force depending on the piston speed without depending on the stroke position. For this reason, when used for suspensions for automobiles, etc., the spring force and damping force are in the same direction when the stroke is from the neutral position to the stroke end side, and the stroke end side is near the neutral position. When moving in the opposite direction, the spring force and damping force are reversed, and there is a large difference in the force to stop vibration when moving away from near the neutral position and when approaching, depending on the required specifications of the vehicle. There was a case.
Also, when used to suppress the deformation of structures, etc., the structure is in the direction of deformation in the direction away from the vicinity of the neutral position, and if the damping force at this time is increased, a large force is also generated at the mounting portion of the damper However, there is a problem that damage to the structure is increased.

  The present invention has been made in view of the above-described conventional problems, and provides a hydraulic damper that increases the damping force toward the vicinity of the neutral position and decreases the damping force in the direction away from the vicinity of the neutral position. is there.

  In order to solve the above-described problems, the present invention provides a cylinder in which oil is sealed, a piston slidably inserted in the cylinder, one end connected to the piston, and the other end connected to the cylinder. A hydraulic damper that generates a damping force by controlling the flow of oil produced by the stroke of the piston, in a neutral position from the stroke end side according to the stroke of the piston. A large damping force is generated when stroked toward the vicinity, and a small damping force is generated when stroked from near the neutral position toward the stroke end side.

  In the present invention, a damping force having the same characteristics as described above may be generated when the piston strokes from the vicinity of the neutral position to either the expansion side or the contraction side.

  According to the hydraulic damper according to the present invention, when used in a suspension for an automobile or the like, a difference in force for stopping vibration between when the vehicle is separated from the vicinity of the neutral position and when the vehicle is approached can be reduced.

  Further, when used to suppress deformation of the structure or the like, it is possible to reduce the damping force when the structure is in the deformation direction, that is, away from the vicinity of the neutral position, and damage to the structure can be reduced.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 and FIG. 2 show a hydraulic damper as one embodiment of the present invention. The hydraulic damper 10 has a single-cylinder gas-filled structure, and a piston 12 and a free piston 13 are slidably fitted in a bottomed cylindrical cylinder 11. One end of a piston rod 14 is connected to the piston 12 using a nut 15, and the other end of the piston rod 14 slides on a rod guide 16 and a guide seal 17 mounted in the opening end of the cylinder 11. It extends through to the outside as possible. Mounting eyes 18 and 19 are integrally provided at the tip of the piston rod 14 of the hydraulic damper 10 and the bottom of the cylinder 11.

  The inside of the cylinder 11 is partitioned into a rod-side oil chamber 20 and a bottom-side oil chamber 21 by a piston 12, and an oil solution is sealed in these oil chambers 20, 21. On the other hand, the bottom side of the cylinder 11 is partitioned as a gas chamber 22 by a free piston 13, and gas (nitrogen gas or the like) is sealed in the gas chamber 22.

  An orifice port 23 is provided on the side wall of the cylinder 11 in the middle of the longitudinal direction, and a first relief outlet port 24 is located on the bottom side of the opening 11 (on the rod guide 16 side). A second relief outlet port 25 is provided at each position (on the free piston 13 side). The first and second relief outlet ports 24 and 25 and the orifice port 23 are communicated with each other by a first relief passage 27 and a second relief passage 28 that share the orifice passage 26 on the orifice port 23 side. A first relief inlet port 29 is located slightly on the opening end side of the second relief outlet port 25 on the side wall of the cylinder 11, and is located slightly on the opening end side of the orifice port 23. Three relief outlet ports 30 are provided, and both ports 29 and 30 are communicated with each other by a third relief passage 31. Further, the second relief inlet port 32 is located slightly on the bottom side of the first relief outlet port 24 on the side wall of the cylinder 11, and the fourth relief outlet port 33 is located slightly on the bottom side of the orifice port 23. Are provided, and both ports 32 and 33 are communicated with each other by a fourth relief passage 34.

  In the orifice passage 26, an orifice-attached low-pressure relief valve 36 having an orifice 35 is disposed so as to relieve the oil in the cylinder 1. The first relief passage 27 communicating with the orifice passage 26 is provided with a first low-pressure relief valve 37 for relieving oil to the rod-side oil chamber 20, and the second relief passage 28 has a rod-side oil. A second low-pressure relief valve 38 that relieves the oil to the chamber 20 is disposed. Further, the third relief passage 31 is provided with a third low-pressure relief valve 39 for relieving oil from the bottom side oil chamber 21 to the rod side oil chamber 20, and the fourth relief passage 34 is provided with a bottom side oil from the rod side oil chamber 20. A fourth low-pressure relief valve 40 that relieves the oil to the chamber 21 is provided. The structure of each of the low pressure relief valves 36 to 40 is substantially the same except for the orifice 35. The valve body 42, a guide 43 for slidably guiding the valve body 42, and the valve body 42 are provided in the casing 41. A valve spring 44 that normally biases in the valve closing direction is housed. The low pressure relief valve 36 with an orifice provides a vertical groove formed in the shaft portion of the valve body 42 as the orifice 35.

  In the present embodiment, two notches 45 and 46 are formed at both ends of the piston 12 as shown in FIG. One notch 45 formed at the end facing the rod-side oil chamber 20 serves to substantially expand the outlet port 30 when the piston 12 passes through the third relief outlet port 30. On the other hand, the other notch 46 formed at the end facing the bottom side oil chamber 21 serves to substantially expand the outlet port 33 when the piston 12 passes through the fourth relief outlet port 33. These notches 45 and 46 are formed by changing their positions in the circumferential direction. Correspondingly, the third relief outlet port 30 and the fourth relief outlet port 33 are positioned in the circumferential direction with respect to the cylinder 11. It is set by changing. In FIG. 1, 47 is a rod stopper that regulates the shortened end of the piston rod 14, and 48 is a rod stopper that regulates the extended end of the piston rod 14.

  Hereinafter, the operation of the hydraulic damper 10 configured as described above will be described with reference to FIGS.

  When the piston 12 strokes in the contracting direction A from the extended end of the piston rod 14 shown in FIG. 4 (1), the oil in the bottom side oil chamber 21 mainly flows out from the orifice port 23 into the orifice passage 26, The orifice relief valve 36 in the orifice passage 26 and the first relief valve 37 in the first relief passage 27 are opened to flow into the rod side oil chamber 20 from the first relief outlet port 24. During this time, a large damping force F1 (FIG. 6) is generated mainly by the orifice 25 in the orifice passage 26 (in the relief valve 36).

  When the piston 12 further strokes in the contracting direction A, first, the third relief outlet port 30 is closed, and then the orifice port 23 is closed. Thus, as soon as the orifice port 23 begins to close, the third relief outlet port 30 is gradually opened to the rod-side oil chamber 20 through one notch 45 of the piston 12. As a result, as shown in FIG. 4 (2), the oil in the bottom side oil chamber 21 flows out from the first relief inlet port 29 into the third relief passage 31, opens the third relief valve 39 and opens the third relief valve 39. 3 Flow begins from the relief outlet port 30 into the rod side oil chamber 20. As shown in FIG. 2B, when the orifice port 23 is completely closed by the piston 12, the oil in the bottom side oil chamber 21 mainly passes through the third relief passage 31 and enters the rod side oil chamber 20. After that, a low damping force F2 is generated according to the stroke of the piston 12. Thereafter, the piston 12 reaches a position immediately before closing the first relief inlet port 29, and at this stage, the movement of the piston 12 in the contracting direction A is stopped by the rod stopper 47 outside the cylinder 11, and the pistol 12 reaches the stroke end. . When the piston rod 14 is contracted, the free piston 13 compresses the gas in the gas chamber 22 and moves to the bottom side in accordance with the intrusion of the piston rod 14 into the cylinder 11. The infiltrated oil liquid is released to the gas chamber 22 side.

  Next, when the piston 12 strokes in the extending direction B from the shortened end of the piston rod 14 shown in FIG. 5 (1), the oil in the rod side oil chamber 20 mainly flows out from the orifice port 23 into the orifice passage 26. Then, the relief valve with orifice 36 in the orifice passage 26 and the second relief valve 38 in the second relief passage 28 are opened to flow into the bottom side oil chamber 21 from the second relief outlet port 25. During this time, a large damping force F4 (FIG. 6) is generated mainly by the orifice 25 in the orifice passage 26 (in the relief valve 36).

  When the piston 12 further strokes in the extending direction B, first, the fourth relief outlet port 33 is closed, and then the orifice port 23 is closed. Thus, at the same time as the orifice port 23 starts to close, the fourth relief outlet port 33 is gradually opened to the bottom side oil chamber 21 through the other notch 46 of the piston 12. As a result, as shown in FIG. 5 (2), the oil in the rod side oil chamber 20 flows out from the second relief inlet port 32 into the fourth relief passage 34, opens the fourth relief valve 40, and The flow starts into the bottom side oil chamber 21 from the 4 relief outlet port 33. When the orifice port 23 is completely closed by the piston 12 as shown in FIG. 2B, the oil in the rod side oil chamber 20 mainly enters the bottom side oil chamber 21 through the fourth relief passage 34. Thereafter, a low damping force F3 (FIG. 6) is generated according to the stroke of the piston 12. The piston 12 then reaches a position just before closing the second relief inlet port 32, and at this stage, the movement in the extension direction B is stopped by the rod stopper 47 inside the cylinder 11, and the pistol 12 reaches the stroke end. . When the piston rod 14 extends, the gas in the gas chamber 22 expands as the piston rod 14 retreats from the cylinder 11 and the free piston 13 moves to the opening end side. The oil solution for the exit is compensated.

  That is, according to the stroke of the piston 12, the hydraulic damper 10 generates large damping forces F1 and F4 when moving from the stroke end side toward the neutral position and from the neutral position toward the stroke end side. When the stroke is made, small damping forces F2 and F3 are generated.

Therefore, when the hydraulic damper of the present invention is used for a suspension for automobiles or the like, large damping forces F1 and F4 are generated when the stroke is from the stroke end side toward the neutral position, but the spring force Works in the opposite direction. Further, when the stroke is from the neutral position toward the stroke end side, small damping forces F2 and F3 are generated, but the spring force works in the same direction. Therefore, the difference in force for stopping the vibration can be reduced between the direction approaching the vicinity of the neutral position and the direction away from the neutral position.
Further, when the hydraulic damper of the present invention is used for a structure such as a house as disclosed in Japanese Patent Application Laid-Open No. 2002-70357, when the amount of deformation of the building increases, that is, from the vicinity of the neutral position toward the stroke end side. During the stroke, the pulling force acting on the mounting part of the hydraulic damper increases, but since the damping force at this time is small, damage to the building can be reduced, and the stroke end side is moved toward the neutral position. Since the large damping forces F1 and F4 are generated during the stroke, a sufficient damping effect can be obtained.

1 is a cross-sectional view schematically showing the overall structure of a hydraulic damper as one embodiment of the present invention. It is sectional drawing which simplifies a hydraulic circuit and shows the whole structure of this hydraulic damper. It is a perspective view which shows the shape of the piston used with this hydraulic damper. It is a schematic diagram which shows the damping force generation state at the time of shortening operation | movement of this hydraulic damper. It is a schematic diagram which shows the damping force generation state at the time of expansion | extension operation | movement of this hydraulic damper. It is a graph which shows the damping-force characteristic of this hydraulic damper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic damper 11 Cylinder 12 Piston 13 Free piston 14 Piston rod 16 Rod guide 17 Guide seal 18 Sub piston rod member 19 Intermediate piston rod member 20 Rod side oil chamber 21 Bottom side oil chamber 23 Orifice port 24, 25, 30, 33 Relief Outlet port 29, 32 Relief inlet port 36 Low pressure relief valve with orifice 37, 38, 39, 40 Low pressure relief valve 45, 46 Notch in piston

Claims (2)

  A cylinder filled with oil, a piston slidably fitted in the cylinder, a piston rod having one end connected to the piston and the other end extending outside the cylinder. A hydraulic damper that generates a damping force by controlling the flow of oil generated by the stroke of the piston, and greatly attenuates when the stroke is from the stroke end side toward the neutral position according to the stroke of the piston. A hydraulic damper that generates a force and generates a small damping force when the stroke is from the neutral position toward the stroke end. 2. The hydraulic damper according to claim 1, wherein a damping force having the same characteristics as described above is generated when the piston strokes from the vicinity of the neutral position to either the expansion side or the contraction side.

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