JP2015121250A - Twin piston damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twin piston damper capable of reducing the number of components with a simple structure.SOLUTION: A twin piston damper includes: a cylinder 3 forming a pressure chamber; an intermediate wall 5 formed in the intermediate part of the cylinder 3 and including a rod insertion hole 15; first and second pistons 7, 9 arranged at both sides of the intermediate wall 5 and forming first and second pressure chambers 14, 16 housing working fluid with respect to the cylinder 3 and the intermediate wall 5; a piston rod 11 inserted into the rod insertion hole 15, connecting the first and second pistons 7, 9 and projecting from the side of the first pressure chamber 14 to the outside of the cylinder 3; and a valve mechanism part 13 formed in the intermediate wall 5 or between the intermediate wall 5 and the piston rod 11 and adjusting inflow and outflow of working fluid between the first and second pressure chambers 14, 16.

Description

  The present invention relates to a twin piston damper that absorbs and reduces the impact of a moving body or the like.

  In general, in a damper using a piston / cylinder device, the volume of the inside of the cylinder changes due to the piston / rod moving into and out of the cylinder, so that the damping characteristic changes between the shock absorption start and the shock absorption end of the moving body. There was a problem.

  On the other hand, there are dampers described in Patent Documents 1, 2, and 3.

  In the damper described in Patent Document 1, the cylinder is configured by an inner and outer cylinder, and an accumulator that absorbs a volume change is provided between the inner and outer cylinders. The damper described in Patent Document 2 is provided with a membrane that bends according to a change in volume in the cylinder. The damper described in Patent Document 3 includes a free piston that moves in accordance with a change in volume in a cylinder.

  With such a structure, the dampers described in Patent Documents 1, 2, and 3 can stabilize the damping characteristics from the start of shock absorption to the end of shock absorption of the moving body.

  However, the damper described in Patent Document 1 has a problem in that the cylinder is configured by an inner and outer cylinder and an accumulator is required, the structure is complicated, the number of parts is large, and assembly and parts management are complicated.

  The dampers described in Patent Documents 2 and 3 have a single cylinder structure, but the damper of Patent Document 2 requires a membrane, and the damper of Patent Document 3 requires a free piston and its mounting structure. Each has a complicated structure and a large number of parts, and there is a problem that assembly and parts management become complicated.

JP 2012-159182 A JP 2009-250403 A JP 2011-231882 A

  The problem to be solved is that the structure is complicated and the number of parts is large, and assembly and parts management become complicated.

  The present invention has a simple structure and can reduce the number of parts, so that a first pressure chamber and a second pressure chamber for accommodating a working fluid are provided in the axial direction, and an intermediate portion of the cylinder. An intermediate wall that is fixed to the cylinder and has a rod insertion hole in the axial center, and is arranged on both sides of the intermediate wall inside the cylinder and divided on both sides of the intermediate wall. The first and second pistons that define the second pressure chamber, and the piston rod that is inserted into the rod insertion hole and is coupled to the first and second pistons so that the end protrudes out of the cylinder. And a valve mechanism part that is formed between the intermediate wall or the intermediate wall and the piston rod and adjusts the inflow and outflow of the working fluid between the first and second pressure chambers.

  Although the twin-piston damper of the present invention is a single-structure cylinder, it suppresses the volume change inside the cylinder due to the piston rod coming into and out of the cylinder without providing a membrane or free piston, and has a damping characteristic. It can be stabilized.

It is sectional drawing of a twin piston damper. Example 1 (A) is sectional drawing of the twin piston damper which concerns on a modification, (B) is sectional drawing of the twin piston damper which concerns on another modification. Example 1 It is sectional drawing of a twin piston damper. (Example 2) (A) is sectional drawing of the twin piston damper which concerns on a modification, (B) is sectional drawing of the twin piston damper which concerns on another modification. (Example 2) It is sectional drawing of a twin piston damper. (Example 3) It is sectional drawing of a twin piston damper. Example 4 It is sectional drawing of a twin piston damper. (Example 5)

  In order to make the structure simple and reduce the number of parts, a cylinder for arranging the first and second pressure chambers for storing the working fluid in the axial direction and a middle part of the cylinder are fixed to the cylinder. An inner wall that is divided into the axial direction and has a rod insertion hole in the axial portion, and a first and a second pressure chamber that are arranged on both sides of the intermediate wall inside the cylinder and divided on both sides of the intermediate wall. The first and second pistons to be formed, the piston rod inserted into the rod insertion hole and coupled to the first and second pistons, and the end portion protruding out of the cylinder, the intermediate wall or the intermediate wall and the piston This is realized by including a valve mechanism portion that is formed between the rods and adjusts the flow of the working fluid between the first and second pressure chambers.

  FIG. 1 is a cross-sectional view of a twin piston damper according to a first embodiment of the present invention.

  The twin piston damper 1 of FIG. 1 is a bidirectional type having a damping function in both directions of pushing and pulling, and includes a cylinder 3, an intermediate wall 5, first and second pistons 7, 9, a piston rod 11, and a valve. The mechanism part 13 is provided.

  The cylinder 3 has a single structure, and is provided for arranging the first and second pressure chambers 14 and 16 for containing the working fluid in the axial direction, and is formed in a straight cylindrical shape with metal or hard resin. Has been. However, the cylinder 3 does not have to be straight as long as a piston described later can operate.

  The intermediate wall 5 is formed of metal or hard resin, and is fixed to the intermediate portion of the cylinder 3 to divide the inside of the cylinder 3 in the axial direction, and includes a circular rod insertion hole 15 in the axial portion. It is formed in a donut shape.

  In this embodiment, the intermediate wall 5 is formed separately from the cylinder 3 and is assembled later. The intermediate wall 5 is fixed to the cylinder 3 with respect to the inner surface of the cylinder 3 by a pair of retaining rings. That is, the intermediate wall 5 is closely fitted and disposed on the inner peripheral surface at the intermediate portion in the axial direction of the cylinder 3 and is positioned in the axial direction by the retaining ring.

  In addition, the fixing structure of the intermediate wall 5 with respect to the cylinder 3 is arbitrary, and a structure in which a screw is screwed from the outside of the cylinder 3 and fixed without using a retaining ring may be employed.

  The intermediate wall 5 includes first and second valve mechanism portions 17 and 19 as the valve mechanism portion 13. The first and second valve mechanism sections 17 and 19 adjust the inflow and outflow of the working fluid between the first and second pressure chambers 14 and 16.

  The first valve mechanism 17 prevents the working fluid from flowing from the first pressure chamber 14 to the second pressure chamber 16 and the working fluid flows from the second pressure chamber 16 to the first pressure chamber 14. Is acceptable.

  The second valve mechanism 19 prevents the working fluid from flowing from the second pressure chamber 16 to the first pressure chamber 14, and the working fluid flows from the first pressure chamber 14 to the second pressure chamber 16. Is acceptable.

  The first and second valve mechanism portions 17 and 19 include orifices 17a and 19a formed through the intermediate wall 5 and valves 17b and 19b for opening and closing the orifices 17a and 19a. The valves 17b and 19b are formed of an elastic body such as rubber.

  In the present embodiment, the first and second valve mechanisms 17 and 19 have the same drag force, but the opening areas of the orifices 17a and 19a are made different or the elastic coefficients of the valves 17b and 19b are made different. Can be set to have different drag.

  The first and second pistons 7 and 9 are made of metal or hard resin, and are arranged on both sides of the intermediate wall 5 to divide the first and second pressure chambers 14 and 16 on both sides of the intermediate wall 5. Form. The first and second pressure chambers 14 and 16 contain a working fluid, and a liquid such as silicone oil is used as the working fluid.

  The first piston 7 is fitted to the intermediate portion of the piston rod 11 on the first pressure chamber 14 side, and the O-ring supported on the inner periphery of the first piston 7 is formed on the outer peripheral surface of the piston rod 11. Close. The first piston 7 is positioned and fixed in the axial direction with respect to the piston rod 11 by a retaining ring via a collar, and the first piston 7 is coupled to the piston rod 11. The outer periphery of the first piston 7 is fitted to the cylinder 3, and the O-ring supported on the outer periphery of the first piston 7 is in close contact with the inner peripheral surface of the cylinder 3.

  The second piston 9 is fitted to one end (inner end) of the piston rod 11 on the second pressure chamber 16 side, and an O-ring supported on the inner periphery of the second piston 9 is a piston rod. 11 is in close contact with the outer peripheral surface. The second piston 9 is positioned and fixed in the axial direction with respect to the piston rod 11 by a retaining ring via a collar, and the second piston 9 is coupled to the piston rod 11. The outer periphery of the second piston 9 is fitted to the cylinder 3, and the O-ring supported on the outer periphery of the second piston 9 is in close contact with the inner peripheral surface of the cylinder 3.

  The piston rod 11 to which the first and second pistons 7 and 9 are coupled is inserted into the rod insertion hole 15, and the other end portion (outer end portion) of the piston rod 11 is the first pressure chamber. It protrudes out of the cylinder 3 from the 14 side. The outer end portion of the piston rod 11 is coupled to the moving body, and is configured to receive an impact input in the pulling direction by pushing from the moving body.

  A communication hole 25 communicating with the second pressure chamber 16 is formed at the inner end of the piston rod 11, and a closing ball 27 is press-fitted. When the pressure in the cylinder 3 becomes high as set, the closing ball 27 is released, and the pressure is released by emergency.

  When the outer end portion of the piston rod 11 protruding from the cylinder 3 receives an impact input from the moving body in the pressing direction, the piston rod 11 enters the cylinder 3 inward, and the first pressure chamber 14 becomes the first pressure chamber 14. Compressed by one piston 7, the second pressure chamber 16 expands as the second piston 9 moves.

  During the compression of the first pressure chamber 14 and the expansion of the second pressure chamber 16, the first valve mechanism 17 prevents the working fluid from flowing from the first pressure chamber 14 into the second pressure chamber 16. The second valve mechanism section 19 allows the working fluid to flow from the first pressure chamber 14 to the second pressure chamber 16.

  That is, the valve 17b of the first valve mechanism portion 17 operates under the pressure of silicone oil and closes the orifice 17a. The valve 19b of the second valve mechanism section 19 operates under the pressure of silicone oil and opens the orifice 19a.

  When the end of the piston rod 11 contracted with respect to the cylinder 3 receives an impact input in the pulling direction from the moving body, the valve 17b of the first valve mechanism portion 17 is made of silicone. It operates under the pressure of oil and opens the orifice 17a. The valve 19b of the second valve mechanism 19 operates by receiving the pressure of silicone oil and closes the orifice 19a.

  Accordingly, a reaction force corresponding to the flow resistance of the silicone oil flowing through the orifice 19a or the orifice 17a acts on the piston rod 11 via the first piston 7, and the piston rod 11 is pushed and pulled with respect to the cylinder 3 in both directions. Can be damped.

  Since the piston rod 11 entering and exiting the cylinder 3 when absorbing the shock moves between the first and second pressure chambers 14 and 16, the first and second pressure chambers 14 and 16 are moved by the movement of the piston rod 11. There is no total volume change between them, and the damping characteristics can be stabilized.

  The cylinder 3 is single, and the structure can be simplified as compared with a structure in which a membrane and a free piston are provided.

[Modification of Example 1]
2A is a cross-sectional view of a twin piston damper according to a modification, and FIG. 2B is a cross-sectional view of a twin piston damper according to another modification.

  The twin piston damper 1 of FIG. 2A has a pushing direction damping function, and the twin piston damper 1 of FIG. 2B has a pulling direction damping function.

  That is, the twin piston damper 1 of FIG. 2 (A) includes only the first valve mechanism portion 17, and the twin piston damper 1 of FIG. 2 (B) includes only the second valve mechanism portion 19. Is.

  The structures of the first and second valve mechanism portions 17 and 19 in FIGS. 2A and 2B are slightly different from those in FIG. 1 with one valve 17b and 19b opening and closing a plurality of orifices 17a and 19a. However, they have substantially the same structure.

  The twin piston damper 1 of FIG. 2 (A) is a return spring composed of a trapezoidal compression coil spring in a side view between the outer end of the piston rod 11 and the end of the cylinder 3. (Not shown) is interposed, and the piston rod 11 is urged in the protruding direction from the cylinder 3 to automatically return.

  The twin piston damper 1 of FIG. 2 (B) is a return spring composed of a trapezoidal coil spring in a side view between the outer end of the piston rod 11 and the end of the cylinder 3. (Not shown) is interposed, and the piston rod 11 is urged in the pulling direction to the cylinder 3 to automatically return.

  FIG. 3 is a sectional view of a twin piston damper according to a second embodiment of the present invention. The basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, the corresponding components are denoted by A, and redundant description is omitted.

  As shown in FIG. 4, the twin piston damper 1 </ b> A of the second embodiment is a bidirectional type having a damping function in both directions of pushing and pulling as in FIG. 1. This twin piston damper 1A has a structure in which an intermediate wall 5A is formed integrally with a cylinder 3A and fixed. The valve mechanism portion 13 </ b> A is formed on the intermediate wall 5 and includes an orifice 28 and an adjusting screw 29.

  The orifice 28 is formed through the intermediate wall 5 </ b> A and communicates between the first and second pressure chambers 14 and 16. The adjusting screw 29 is screwed into the intermediate wall 5A from the outside of the cylinder 3A, and is arranged so that the tip reaches the orifice 28. By adjusting the adjustment screw 29 from the outside of the cylinder 3A, the flow passage area of the orifice 28 can be externally adjusted.

  Accordingly, the twin piston damper 1A operates in the same manner as in the first embodiment, and the silicone oil flows through the orifice 28 when the first and second pressure chambers 14 and 16 contract and expand, and the piston rod for the cylinder 3 11 can be damped in both pushing and pulling impacts.

  By screwing the adjusting screw 29 from the outside of the cylinder 3 and adjusting the screw return, the flow area of the orifice 28 can be adjusted to the outside, and the damping characteristic can be easily changed.

  Since the adjusting structure using the adjusting screw 29 is provided on the fixed intermediate wall 5A, the manufacturing is easy.

In addition, the same effects as those of the first embodiment can be achieved.
[Modification of Example 2]
FIG. 4A is a cross-sectional view of a twin piston damper according to a modification, and FIG. 4B is a cross-sectional view of a twin piston damper according to another modification.

  The twin piston damper 1A of FIG. 4A has a pushing direction damping function, and the twin piston damper 1A of FIG. 4B has a pulling direction damping function.

  That is, the twin piston damper 1A shown in FIGS. 4A and 4B includes a check valve 31 having a valve mechanism portion 13A formed on the intermediate wall 5A. The check valve 31 in FIG. 4A prevents the flow of silicone oil from the first pressure chamber 14 to the second pressure chamber 16, and the check valve 31 in FIG. Inflow of silicone oil from the pressure chamber 16 to the first pressure chamber 14 is prevented.

  Accordingly, in the twin piston damper 1A shown in FIG. 4A, in the same operation as in the first embodiment, when the first pressure chamber 14 contracts, the silicone oil flows only through the orifice 28, and the second pressure chamber 16 Since the silicone oil flows through the orifice 28 and the check valve 31 at the time of contraction, the impact in the pushing direction of the piston rod 11 against the cylinder 3 can be damped by setting the opening area of the orifice 28.

  In the twin piston damper 1A shown in FIG. 4B, in the same operation as in the first embodiment, when the first pressure chamber 14 contracts, silicone oil flows through the orifice 28 and the check valve 31 together. Since the silicone oil flows only through the orifice 28 when the pressure chamber 16 contracts, the impact in the pulling direction of the piston rod 11 on the cylinder 3 can be damped by setting the opening area of the orifice 28.

  Similar to the modified example of FIG. 2, the twin piston damper 1 of FIG. 4 (A) has a trapezoidal compression coil in a side view between the outer end of the piston rod 11 and the end of the cylinder 3A. A return spring (not shown) composed of a spring is interposed, and the twin piston damper 1 in FIG. 4B is provided between the outer end of the piston rod 11 and the end of the cylinder 3A. A return spring (not shown) composed of a trapezoidal tension coil spring in a side view is interposed, and similarly performs a return function.

  FIG. 5 is a cross-sectional view of a twin piston damper according to Embodiment 3 of the present invention. Note that the basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, the corresponding components are denoted by the same reference numerals B, and redundant description is omitted.

  As shown in FIG. 5, the valve mechanism 13B of the twin piston damper 1B according to the third embodiment includes first and second valve mechanisms 17B and 19B.

  The second valve mechanism portion 19B is formed between the intermediate wall 5B and the piston / rod 11B, and includes an edge portion 19Ba and a pressure adjusting groove 19Bb.

  The edge portion 19Ba is formed by a tapered hole of the rod insertion hole 15B of the intermediate wall 5B, and is configured to be close to or slidably contact the outer periphery of the piston rod 11B. This proximity or sliding contact restricts the flow of the working fluid between the first and second pressure chambers 14 and 16.

  The pressure adjusting groove 19Bb is formed along the axial direction on the outer periphery of the piston rod 11B, and the depth with respect to the edge portion 19Ba gradually decreases with the movement of the piston rod 11B toward the second pressure chamber 16 with respect to the edge portion 19Ba. It is formed to become. The pressure adjusting groove 19Bb can be formed with a constant depth or eliminated on the second pressure chamber 16 side. Instead of forming the pressure adjusting groove 19Bb so that the depth becomes gradually shallower as described above, the width can be made gradually narrower, or it can be made so that the depth becomes gradually shallower and the width becomes gradually narrower. it can. Further, a plurality of pressure adjusting grooves 19Bb are formed, are formed to be longer stepwise on the first pressure chamber 14 side, and gradually move toward the edge portion 19Ba as the piston rod 11B moves toward the second pressure chamber 16 side. It can also be formed to disappear. The pressure adjusting groove 19Bb can be formed not only linearly in the axial direction but also in a spiral shape.

  The first valve mechanism portion 17B includes an orifice 17Ba and a valve 17Bb as in the first embodiment.

  The orifice 17Ba is formed through the intermediate wall 5B.

  The valve 17Bb is operated by the pressure from the working fluid to open and close the orifice 17Ba to prevent the working fluid from flowing from the first pressure chamber 14 to the second pressure chamber 16 and from the second pressure chamber 16 to the first pressure chamber 16B. The working fluid is allowed to flow into the pressure chamber 14.

  In the twin piston damper 1B, a return spring 33 composed of a trapezoidal compression coil spring in a side view is interposed between the outer end of the piston rod 11B and the end of the cylinder 3B. The piston rod 11B is biased in the protruding direction from 3B.

  This twin piston damper 1B has a depth of the pressure regulating groove 19Bb facing the edge portion 19Ba as the piston rod 11B moves toward the second pressure chamber 16 with respect to the edge portion 19Ba when the first pressure chamber 14 contracts. Gradually becomes shallower and the flow resistance of the silicone oil to the pressure adjusting groove 19Bb gradually increases.

  When the second pressure chamber 16 contracts, the depth of the pressure adjusting groove 19Bb facing the edge portion 19Ba gradually increases as the piston rod 11B moves toward the first pressure chamber 14 with respect to the edge portion 19Ba. The flow resistance of silicone oil to the groove 19Bb gradually decreases. At the same time, the valve 17Bb of the first valve mechanism 17B operates under the pressure of silicone oil to open the orifice 17Ba. With this operation, silicone oil flows from the second pressure chamber 16 to the first pressure chamber 14 through the orifice 17Ba.

  Therefore, a reaction force corresponding to the flow resistance of the silicone oil flowing through the pressure adjusting groove 19Bb acts on the piston rod 11B via the first piston 7 when an impact is applied to the piston rod 11B in the pushing direction, and the cylinder 3 can be damped in the pushing direction of the piston rod 11 with respect to 3.

  After the end of the damping, the piston rod 11B is urged in the protruding direction from the cylinder 3 by the urging force of the return spring 33 so that it automatically returns.

  In addition, the same effects as those of the first embodiment can be achieved.

  Further, in this embodiment, since the pressure adjusting groove 19Bb is formed in the piston rod 11B, the manufacturing becomes easier than various kinds of processing on the inner surface of the cylinder 3. In particular, as the twin piston damper 1B becomes smaller, the operation of the tool inside the cylinder 3 is restricted. However, the processing of the outer surface of the piston rod 11B can be performed very easily. The damping characteristic can be easily changed by changing the depth of the pressure adjusting groove 19Bb, changing the width, or changing the depth and width.

  FIG. 6 is a sectional view of a twin piston damper according to a fourth embodiment of the present invention. The basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, the corresponding components are denoted by C, and the duplicated description is omitted.

  As shown in FIG. 6, the valve mechanism 13C of the twin piston damper 1C of the fourth embodiment is composed of first and second valve mechanisms 17C and 19C.

  In the present embodiment, the second valve mechanism portion 19C includes a seal 19Ca, and includes a pressure adjusting hollow portion 19Cb and a plurality of pressure adjusting through-hole portions 19Cc.

  The seal 19Ca is composed of, for example, an O-ring, is provided in the rod insertion hole 15C of the intermediate wall 5C, and is in close contact with the outer periphery of the piston rod 11C. The seal 19Ca can be omitted.

  The pressure adjusting hollow portion 19Cb is formed along the axial direction of the piston rod 11C and extends over the first and second pressure chambers 14 and 16. The plurality of pressure regulating through holes 19Cc are formed along the pressure regulating hollow portion 19Cb, and are continuously provided so as to communicate the pressure regulating hollow portion 19Cb with the first pressure chamber 14 and the second pressure chamber 16. Yes. That is, the plurality of pressure regulation through holes 19Cc are continuously provided at predetermined intervals along the axial direction of the piston rod 11C, and open the pressure regulation hollow portion 19Cb to the outside of the piston rod 11C.

  The first valve mechanism portion 17C includes an orifice 17Ca and a valve 17Cb as in the first embodiment.

  The orifice 17Ca is formed through the intermediate wall 5C.

  The valve 17Cb is operated by the pressure from the working fluid to open and close the orifice 17Ca to prevent the working fluid from flowing from the first pressure chamber 14 to the second pressure chamber 16 and from the second pressure chamber 16 to the first pressure chamber 16Cb. The working fluid is allowed to flow into the pressure chamber 14.

  A communication hole 25C communicating with the second pressure chamber 16 is formed at the inner end of the piston rod 11C, and a closing cap 27C is press-fitted. When the pressure in the first and second pressure chambers 14 and 16 becomes high as set, the closing cap 27C is released, and the pressure is released by emergency.

  The twin-piston damper 1C has a pressure regulation through hole 19Cc that exists on the first pressure chamber 14 side as the piston rod 11C moves to the second pressure chamber 16 side when the first pressure chamber 14 contracts. The number decreases.

  Due to the decrease of the pressure adjusting through hole 19Cc existing on the first pressure chamber 14 side, the first pressure chamber 14 is connected to the second pressure chamber 16 through the pressure adjusting through hole 19Cc and the pressure adjusting hollow 19Cb. The flow resistance of silicone oil gradually increases.

  When the second pressure chamber 16 contracts, the number of pressure regulation through holes 19Cc existing on the second pressure chamber 16 side decreases with the movement of the piston rod 11C to the first pressure chamber 14 side. The valve 17Cb of the first valve mechanism 17C operates under the pressure of silicone oil to open the orifice 17Ca. By this operation, the silicone oil flows from the second pressure chamber 16 to the first pressure chamber 14 through the orifice 17Ca.

  Therefore, a reaction force corresponding to the flow resistance of the silicone oil flowing through the pressure adjusting through hole 19Cc and the pressure adjusting hollow portion 19Cb when an impact is applied in the pushing direction to the piston rod 11C is transmitted through the first piston 7. Acting on the piston rod 11C, the impact in the pushing direction of the piston rod 11 on the cylinder 3 can be damped.

  In addition, the same effects as those of the first embodiment can be achieved.

  Also in the present embodiment, as in the third embodiment, the pressure adjusting hollow portion 19Cb and the pressure adjusting through hole portion 19Cc are formed in the piston rod 11C, so that the manufacture is facilitated. The damping characteristic can be easily changed by changing the number of pressure regulation through holes 19Cc.

  FIG. 7 is a cross-sectional view of a twin piston damper according to a fifth embodiment of the present invention. The basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, the corresponding components are denoted by the same reference numerals, and duplicate descriptions are omitted.

  As shown in FIG. 7, in the twin piston damper 1D of the fifth embodiment, the valve mechanism portion 13D is composed of first and second valve mechanism portions 17D and 19D.

  The second valve mechanism portion 19D includes an edge portion 19Da and a pressure regulating taper portion 19Db.

  The edge portion 19Da is formed by a tapered hole of the rod insertion hole 15D of the intermediate wall 5D and is configured to be close to the outer periphery of the piston rod 11D. This proximity restricts the flow of the working fluid between the first and second pressure chambers 14 and 16.

  The pressure regulation taper portion 19Db is formed along the axial direction on the outer periphery of the piston rod 11D. The pressure adjusting taper portion 19Db is formed so as to gradually increase in diameter with respect to the edge portion 19Da as the piston rod 11D moves toward the second pressure chamber 16 with respect to the edge portion 19Da.

  As in the first embodiment, the first valve mechanism portion 17D includes an orifice 17Da and a valve 17Db.

  The orifice 17Da is formed through the intermediate wall 5D.

  The valve 17Db is operated by the pressure from the working fluid to open and close the orifice 17Da to prevent the working fluid from flowing from the first pressure chamber 14 to the second pressure chamber 16, and from the second pressure chamber 16 to the first pressure chamber 16Db. The working fluid is allowed to flow into the pressure chamber 14.

  Therefore, in the twin piston damper 1D, when the first pressure chamber 14 contracts, the piston rod 11D moves toward the second pressure chamber 16 with respect to the edge portion 19Da and the pressure regulating taper portion 19Db facing the edge portion 19Da The diameter gradually increases, and the flow resistance of the silicone oil between the edge portion 19Da and the pressure regulation taper portion 19Db gradually increases.

  When the second pressure chamber 16 contracts, the diameter of the pressure adjusting taper portion 19Db facing the edge portion 19Da gradually decreases with the movement of the piston rod 11D toward the first pressure chamber 14 with respect to the edge portion 19Da. The flow resistance of silicone oil between 19 Da and the pressure regulation taper portion 19 Db gradually decreases. At the same time, the valve 17Db of the first valve mechanism 17D operates under the pressure of silicone oil to open the orifice 17Da. By this operation, the silicone oil flows from the second pressure chamber 16 to the first pressure chamber 14 through the orifice 17Da.

  Therefore, a reaction force corresponding to the flow resistance of the silicone oil flowing between the edge portion 19Da and the pressure regulating taper portion 19Db when an impact is applied in the pushing direction to the piston rod 11D is caused to pass through the first piston 7 to the piston- Acting on the rod 11D, the impact in the pushing direction of the piston rod 11 against the cylinder 3 can be damped.

  In addition, the same effects as those of the first embodiment can be achieved.

  Further, in the present embodiment, since the pressure adjusting taper portion 19Db is formed in the piston rod 11D, the manufacture becomes easier than various kinds of processing on the inner surface of the cylinder 3. In particular, as the twin piston damper 1D becomes smaller, the operation of the tool inside the cylinder 3D is restricted. However, the processing of the outer surface of the piston rod 11D can be performed very easily.

1, 1A, 1B, 1C, 1D Twin Piston Damper 3, 3A, 3B, 3C, 3D Cylinder 5, 5A, 5B, 5C, 5D Intermediate Wall 7 First Piston 9 Second Piston 11, 11B, 11C, 11D Piston rod 13, 13A, 13B, 13C, 13D Valve mechanism part 15, 15B, 15C, 15D Rod insertion hole 17, 17B, 17C, 17D First valve mechanism part 17a, 17Ba, 17Ca, 17Da Orifice 17b, 17Bb , 17Cb, 17Db Valve 19, 19B, 19C, 19D Second valve mechanism portion 19Ba, 19Da Edge portion 19Ca Seal 19Bb Pressure adjusting groove 19Cb Pressure adjusting hollow portion 19Cc Pressure adjusting through hole portion 19Db Pressure adjusting taper portion 28 Orifice 29 Adjustment screw 31 Check valve

Claims (8)

A cylinder for arranging the first and second pressure chambers containing the working fluid in the axial direction;
An intermediate wall fixed to an intermediate portion of the cylinder and partitioned in the axial direction inside the cylinder and having a rod insertion hole in the axial portion;
A first piston and a second piston which are arranged on both sides of the intermediate wall inside the cylinder and which divide and form the first and second pressure chambers on both sides of the intermediate wall;
A piston rod that is inserted into the rod insertion hole and that connects the first and second pistons and has an end protruding out of the cylinder;
A valve mechanism part that is formed between the intermediate wall or the intermediate wall and the piston rod, and adjusts the flow of working fluid between the first and second pressure chambers;
Twin piston damper characterized by having The twin piston damper according to claim 1,
The valve mechanism section prevents the working fluid from flowing from the first pressure chamber into the second pressure chamber and prevents the working fluid from flowing from the second pressure chamber into the first pressure chamber. A first valve mechanism section to be permitted, and the operation from the first pressure chamber to the second pressure chamber by preventing the working fluid from flowing from the second pressure chamber to the first pressure chamber. A second valve mechanism that allows inflow of fluid;
Twin piston damper characterized by having The twin piston damper according to claim 1,
The valve mechanism section prevents or allows the working fluid to flow from the first pressure chamber to the second pressure chamber, and allows the working fluid to flow from the second pressure chamber to the first pressure chamber. Allow or block the inflow of
A twin-piston damper characterized by having The twin piston damper according to claim 1,
The valve mechanism portion is formed through the intermediate wall and communicates between the first and second pressure chambers, and an adjustment screw that is screwed into the intermediate wall from outside the cylinder and externally adjusts the flow area of the orifice. Is
This is a twin piston damper. The twin piston damper according to claim 4,
The valve mechanism portion is formed on the intermediate wall and prevents the inflow of the working fluid from the first pressure chamber to the second pressure chamber or from the second pressure chamber to the first pressure chamber. A check valve for preventing the working fluid from flowing into the pressure chamber;
This is a twin piston damper. The twin piston damper according to claim 1,
The valve mechanism portion opens and closes an orifice formed through the intermediate wall and a pressure from the working fluid to prevent the working fluid from flowing from the first pressure chamber to the second pressure chamber. A first valve mechanism comprising a valve that allows the working fluid to flow into the first pressure chamber from the second pressure chamber, and the rod insertion hole formed near the outer periphery of the piston rod The edge portion and the outer periphery of the piston rod are formed along the axial direction or formed in a spiral shape, and the depth with respect to the edge portion is moved along with the movement of the piston rod with respect to the edge portion toward the second pressure chamber. Are formed so that the width gradually becomes narrower as the depth gradually becomes shallower or the width becomes gradually narrower. And a second valve mechanism comprising at formed adjusted groove so as to gradually disappear with respect to the edge portion with the movement of the second pressure chamber side of tons rod,
This is a twin piston damper. The twin piston damper according to claim 1,
The valve mechanism portion opens and closes an orifice formed through the intermediate wall and a pressure from the working fluid to prevent the working fluid from flowing from the first pressure chamber to the second pressure chamber. A first valve mechanism portion comprising a valve that allows inflow of the working fluid from the second pressure chamber to the first pressure chamber, and the first and second portions along the axial direction of the piston rod. A pressure adjusting hollow portion extending over two pressure chambers, and a plurality of pressure adjusting through-hole portions continuously provided so as to communicate the pressure adjusting hollow portion with the first pressure chamber and the second pressure chamber. Consisting of a second valve mechanism,
This is a twin piston damper. The twin piston damper according to claim 1,
The valve mechanism portion opens and closes an orifice formed through the intermediate wall and a pressure from the working fluid to prevent the working fluid from flowing from the first pressure chamber to the second pressure chamber. A first valve mechanism comprising a valve that allows the working fluid to flow into the first pressure chamber from the second pressure chamber, and the rod insertion hole formed near the outer periphery of the piston rod The edge portion and the outer periphery of the piston rod are formed along the axial direction so as to gradually increase in diameter with respect to the edge portion as the piston rod moves relative to the edge portion toward the second pressure chamber. Comprising a second valve mechanism portion comprising a pressure regulating taper portion,
This is a twin piston damper.

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