JP5356563B2 - Shock absorber filled with viscoelastic fluid - Google Patents

Description

  In order to mitigate the acceleration caused by the collision of the object and prevent the generation of an excessive impact force, a shock absorber or a damper is applied. As this type of shock absorber, a spring shock absorber, a friction shock absorber, a rubber shock absorber, a fluid shock absorber such as hydraulic pressure or air pressure, and the like are known, but the present invention belongs to the fluid shock absorber. More specifically, it comprises a first member having a pair of inner wall portions arranged at a predetermined interval, and a second member provided between the pair of inner wall portions of the first member, The present invention relates to a shock absorber using a viscoelastic fluid that attenuates vibrations and impacts caused by changes in external force acting between the first and second members.

  A fluid shock absorber is used as a seismic isolation or vibration control device for a building such as a bridge or a building, and as a shock absorber for absorbing an impact between connected railway vehicles. The fluid shock absorber or the fluid damping device is schematically composed of a cylinder, a piston reciprocally provided in the cylinder, and a communication pipe communicating two chambers of the cylinder partitioned by the piston. It is made up of. The cylinder is filled with a viscous fluid. Therefore, when an external force is applied to the piston from the piston rod and the piston moves, the viscous fluid in one chamber moves to the other chamber through the communication pipe. At this time, the kinetic energy is absorbed by the dynamic pressure resistance and the viscous resistance due to the orifice effect.

  Various fluid shock absorbers as described above have been conventionally proposed in, for example, Patent Documents 1 to 4 and the like. Specifically, as shown in FIG. 4, Patent Document 1 includes a cylinder 50 and a piston 51 that is reciprocally movable in the cylinder 50, and the cylinder 50 is filled with an elastomer. A shock absorber is shown. There is an annular passage 52 between the inner peripheral wall of the cylinder 50 and the outer peripheral surface of the piston 51, and the piston 51 has communication passages 54, 54 communicating the first chamber 50a and the second chamber 50b of the cylinder 50. Opened. Plate-shaped valve lids 55 and 55 are provided on the side of the first chamber 50 a of these communication passages 54 and 54. Therefore, when the piston rod 51 ′ is pushed in the direction of the arrow F, the elastomer in the first chamber 50a passes through both the annular passage 52 and the passages 54, 54 when the piston rod 51 ′ is pushed at a normal speed. It flows toward 50b. On the other hand, when pushed at a high speed, the plate-like valve lids 55, 55 close the communication passages 54, 54, so that only the annular passage 52 flows. Thereby, a large damping force is obtained. When the pushing force F disappears, the piston 51 returns to the original initial position by the restoring force of the elastomer.

  Patent Document 2 discloses a liquid pressure spring including a cylinder and a piston that is reciprocally movable in the cylinder. A female screw is cut on the inner peripheral wall of the open end of the cylinder, and the male screw of the lid is screwed into this female screw. Therefore, by enclosing the compressible fluid in the cylinder and adjusting the screwing amount of the lid, the inner volume of the cylinder can be increased / decreased, and the enclosing pressure of the compressive fluid can be adjusted. When a unidirectional force is applied to the piston rod outside the cylinder, the compressible fluid in one chamber of the cylinder passes between the inner peripheral surface of the cylinder and the outer peripheral surface of the piston to the other chamber. Moving. At this time, it is similarly attenuated. When the force in one direction is lost, the restoring force of the compressive fluid returns to the initial position as in the shock absorber described in Patent Document 1.

Japanese National Patent Publication No. 10-512942 JP 2008-175266 A Japanese Patent Laid-Open No. 9-21775 JP 2005-220936 A

  Patent Document 3 proposes a damping device including a cylinder and a piston that is reciprocally movable in the cylinder. The cylinder is partitioned into first and second chambers by a piston head. The first and second chambers are connected by a communication pipe having an orifice action. Therefore, when a unidirectional force acts on the piston rod, the viscous fluid sealed in the cylinder flows from the first chamber to the second chamber through the communication pipe, for example. When a force in the other direction acts, this time, on the contrary, it flows from the second chamber through the communication pipe to the first chamber. Thereby, a bidirectional attenuation effect is obtained. In addition, this damping device has a first coil spring in the first chamber of the cylinder and a second spring in the second chamber. Alternatively, the first and second coil springs are provided outside the first and second chambers, respectively.

  FIG. 5 shows a bidirectional vibration damper proposed by Patent Document 5. This bidirectional vibration damper is composed of upper and lower viscoelastic bodies R1, R2 made of epoxy resin and arranged in series in the vertical direction. These viscoelastic bodies R <b> 1 and R <b> 2 have a columnar shape and are attached between the seat plate 60 and the support plate 61 in a state of being somewhat compressed by a pair of compression side rods 62 and 62. A partition plate 63 is interposed between the upper and lower viscoelastic bodies R1 and R2. The partition plate 63 and the upper bracket 64 are rigidly connected by a pair of rods 65 and 65. Therefore, when a downward compressive force acts on the upper bracket 64, the partition plate 63 pushes the lower viscoelastic body R2 downward, and the lower viscoelastic body R2 swells as shown in FIG. Conversely, when an upward pulling force is applied to the upper bracket 64, the partition plate 63 pushes the upper viscoelastic body R1 upward, and the upper viscoelastic body R1 swells. This state is shown in FIG. By deforming in this way, a damping action in the vertical direction or in both directions can be obtained. Further, when the action of the vertical force is lost, the partition plate 63 returns to the original initial position by the restoring force of the upper and lower viscoelastic bodies R1 and R2 made of epoxy resin.

  According to the shock absorber proposed in Patent Documents 1 and 2, when an external force acts on the piston rod, the piston moves and acts on the elastomer or compressive fluid filled in the cylinder to obtain a damping action. When the action of the external force disappears, the elastomer or compressible fluid is compressed to some extent when it exhibits a damping action, so that the restoring force causes the piston to return to the original initial position. Therefore, there is no particular problem as a shock absorber for an external force in one direction, but it is not convenient because the external force is not always in one direction. That is, if a one-way shock absorber is installed in parallel or in the opposite direction in series, a problem remains in installation space, cost, etc., even if bidirectional buffer is obtained.

  On the other hand, the damping devices described in Patent Documents 3 and 4 are directly related to the present invention, exhibiting a damping action with respect to a bidirectional external force, and returning to the original initial position when the action of the external force is lost. The returning action is obtained. However, there are problems to be improved. For example, since the damping device described in Patent Document 3 is provided with a coil spring in addition to a cylinder for viscous fluid, the structure is complicated, the size is increased, and the cost is increased. The damper described in Patent Document 4 is arranged in series in order for a viscoelastic body made of a solid such as an epoxy resin to exhibit bidirectionality, becomes longer in the axial direction, and becomes structurally complicated. Yes. In addition, the epoxy resin has an extremely small damping characteristic compared with the viscous fluid, and there is a problem that deterioration is inevitable and regular maintenance is required.

  Therefore, the present invention has a viscoelasticity that is structurally compact, has a large damping action in both the compression direction and the pulling direction, has a small maintenance problem, and automatically returns to its initial position when no external force is applied. It is an object to provide a shock absorber in which a fluid is enclosed.

  In order to achieve the above object, the present invention applies a cylinder in which a viscoelastic fluid is enclosed. The cylinder is provided with a pair of pistons. These piston heads are located opposite to each other in the cylinder, and the piston rod protrudes from the cylinder side wall, and the tip of the piston rod is in a state where the rod side of the piston head, that is, the back surface is in contact with the cylinder side wall. It is comprised so that each contact part arrange | positioned at predetermined intervals may be contact | connected. The first member is the part made up of the contact portions arranged at a predetermined interval, and the second part is the part made up of the cylinder, which attenuates vibrations and impacts caused by external forces acting between these first and second members. Or it is comprised so that it may buffer. In another aspect of the invention, the tip of the piston rod is configured to contact each contact portion arranged at a predetermined interval in a state where there is a predetermined interval between the back surface of the piston head and the cylinder side wall. The

  That is, in order to achieve the above-mentioned object, the invention according to claim 1 is provided between a first member having a pair of abutting portions arranged at a predetermined interval and the pair of abutting portions. A shock absorber for attenuating vibrations / impacts caused by a change in external force acting between the first and second members, wherein the second member has cylinder sidewalls at both ends. And a pair of first and second pistons, the piston heads of which are opposed to each other, and an inner peripheral surface of the cylinder and outer peripheries of the first and second piston heads An annular channel having a predetermined interval in which a viscoelastic fluid sealed at a predetermined pressure flows is formed between the piston and each surface, and each piston rod of the piston is connected to the outside from the cylinder side wall. To the piston In a state where the back of the de is in contact with the cylinder side wall, the distal end is in contact with the pair of contact portions.

  The invention according to claim 2 includes a first member having a pair of abutting portions arranged at a predetermined interval, and a second member provided between the pair of abutting portions, A shock absorber for attenuating vibration / impact caused by a change in external force acting between the first and second members, wherein the second member includes a cylinder having cylinder side walls at both ends, and an inside of the cylinder. The piston head is composed of a pair of first and second pistons facing each other, and a predetermined amount is formed between the inner peripheral surface of the cylinder and the outer peripheral surfaces of the first and second piston heads. An annular flow path with a predetermined interval through which the viscoelastic fluid sealed by pressure flows is formed, and each piston rod of the piston exits from the cylinder side wall, and the back surface of the piston head is Cylinder side wall and predetermined While being spaced intervals only, the distal end is in contact respectively with the pair of contact portions. According to a third aspect of the present invention, in the shock absorber according to the first or second aspect, the first member and the second member are applied to a connector device of a railway vehicle.

As described above, according to the present invention, a shock absorber that attenuates vibrations / impacts caused by a change in external force acting between the first and second members, the second member has cylinder side walls at both ends. And a pair of first and second pistons whose piston heads are opposed to each other inside the cylinder, and an inner peripheral surface of the cylinder and an outer peripheral surface of the first and second piston heads An annular flow path with a predetermined interval through which a viscoelastic fluid sealed at a predetermined pressure flows is formed between the piston rods and the piston rods of the piston. In this state, the front end of the piston head is in contact with the pair of contact portions while the back surface of the piston head is in contact with the cylinder side wall, so that the external force acting between the first and second members changes. If there is a pair of pins Tong the tip portion of the rod is in contact with the contact portion of the first and second, towards the cylinder moves. By this movement, the viscoelastic fluid sealed at a predetermined pressure in the cylinder flows through the one annular channel to the back side of the piston head. Thereby, a damping effect is obtained. When the cylinder moves in this way, one piston rod enters the cylinder, so that the apparent volume of the cylinder decreases, the pressure of the viscoelastic fluid increases, and the reaction force and damping effect are further enhanced. When the action of the external force disappears, the pressure on the front side of one piston head is larger than the pressure on the rear side, so that one piston head is pushed out, but the tip of the rod is in the first contact. Since it is in contact with the part, it cannot be pushed out, and the cylinder moves as a reaction. That is, the cylinder returns to the initial position.
As described above, according to the present invention, the first and second members return to the initial positions when the external force changes, that is, the vibration and impact in both directions of the compression direction and the pulling direction are buffered and the action of the external force is lost. The effect is obtained. Further, according to the present invention, since a viscoelastic fluid is used, a higher reaction force and damping effect can be obtained as compared with an epoxy resin shock absorber, a rubber shock absorber and the like. Furthermore, since the viscoelastic fluid is sealed in the cylinder and isolated from the external environment, there is almost no problem of deterioration compared to epoxy resin shock absorbers, rubber shock absorbers, etc., and there is also an effect that maintenance is substantially unnecessary. can get.

According to a second aspect of the present invention, the piston rod of each of the pistons is configured to be substantially the same as the above-described aspect of the present invention. Since the tip end part is in contact with the pair of contact parts in a state where there is a predetermined interval between them, if there is a change in the external force acting between the first and second members, the cylinder is more The viscoelastic fluid flows through the one annular channel to the back side of the piston head while the cylinder moves “the predetermined interval”. As a result, a damping effect can be obtained. However, unlike the above-described invention, even if the cylinder moves, the volume does not decrease, so that a large reaction force characteristic cannot be obtained. Further, even if the external force is no longer applied, it can be restored by the restoring force of the viscoelastic fluid and does not return to the initial position almost completely as in the above invention.
When the cylinder moves beyond the "predetermined interval" due to a large external force, the other piston moves together with the cylinder as the back surface of the head is dragged to the second cylinder side wall. In addition, the volume of the cylinder is reduced, and a large reaction force and damping effect can be obtained. When the action of the external force disappears, it automatically returns until “the predetermined interval”.
As described above, according to the second invention, a return range that is narrow and different from the reaction force of two kinds of large and small can be obtained. Therefore, when applied to a shock absorber such as a building or a bridge structure, a small external force such as a wind load is applied. The vibration / damping effect can be obtained, and there is an advantage that unnecessary reaction force is not applied within the range of linear expansion caused by thermal radiation. In addition, there is an advantage that a large vibration / damping effect can be obtained for a large load such as an earthquake and an external force having a large amplitude.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the buffer which concerns on the 1st Embodiment of this invention, The (a) is a front view which shows the whole in an initial position by making a partial cross section, The (a) is an external force in one direction. Is a cross-sectional view of the main part showing the state where the cylinder has moved by a predetermined amount, and (c) is a cross-sectional view of the main part showing a stage in the middle of the return of the cylinder to the initial position without the action of external force. is there. It is a figure which shows typically the buffer which concerns on the 2nd Embodiment of this invention, The (a) is a front view which shows the whole in an initial position by making a partial cross section, The (a) is an external force in one direction. Is a cross-sectional view of the main part showing the state where the cylinder has moved by a predetermined amount, and (c) is a cross-sectional view of the main part showing a stage in the middle of the return of the cylinder to the initial position without the action of external force. is there. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the buffer which concerns on the 1st Embodiment of this invention, The (a) is sectional drawing which shows the state which each component occupies the initial position, The (a) occupies the compression state, respectively. . It is sectional drawing which shows the principal part of the prior art example described in patent document 1. It is a figure which shows the prior art example described in patent document 4, The (a) is a compression state, The (a) is a front view typically shown in a tension | pulling state, respectively.

  First, the principle of the shock absorber or the shock absorber according to the first embodiment of the present invention will be described with reference to FIG. The shock absorber according to the present embodiment is a bridge, a building, or the like as a device that cushions / absorbs vibrations, shocks, etc. caused by a change in external force acting between structures or a change in relative distance between structures. Although applied as a seismic isolation device for buildings, an example applied to a railway vehicle coupling device that is easy to imagine will be described below. Further, as will be apparent from the following description, the shock absorber according to the present embodiment acts equally in the compression direction and the pulling direction, so that the cylinder side wall, the pair of pistons, etc. have the same structure. The member located on the left side will be described as being distinguished from the first member, and the member located on the right side will be distinguished from the second member.

  As is well known, the connecting device includes a connector and a shock absorber. In FIG. 1A, a portion indicated by reference numeral 1 is a connector portion, a portion indicated by 10 is a shock absorber portion, and a portion rigidly connected to a cylinder constituting the shock absorber portion 10 is a companion plate. Each part 20 is shown. The companion plate portion 20 is adapted to be attached to the companion plate guard of the vehicle body. Therefore, according to the present embodiment, when the connected vehicle travels, a relative position change, that is, vibration / impact occurs between the connector unit 10 and the companion plate unit 20.

  The connector unit 1 includes a pair of first and second contact plates 2a and 2b arranged at a predetermined interval, and a plurality of the contact plates 2a and 2b that are rigidly coupled to each other. It consists of a bar member 3 (3). A conventionally known coupler 5 is attached to the outside of the first contact plate 2a.

  The shock absorber portion 10 includes a cylinder 11 in which a so-called viscoelastic fluid having viscosity and compressibility is sealed in a pressurized state, and a pair of first and second pistons provided in the cylinder 11 so as to be reciprocally movable. 14a and 14b. These pistons 14a, 14b are composed of piston heads 15a, 15b having a predetermined diameter and piston rods 16a, 16b. The piston heads 15a, 15b are positioned facing the cylinder 11, and the piston rods 16a, 16b are the first ones. It passes through the cylinder side walls 12a and 12b of the first and second cylinders and is exposed to the outside through the respective seals S and S. According to the first embodiment shown in FIG. 1, when the rod side surfaces of the first and second piston heads 15a and 15b, that is, the back surfaces are seated on the inner surfaces of the cylinder side walls 12a and 12b, the piston rod The tips of 16a and 16b are in contact with the side surfaces of the first and second contact plates 2a and 2b, respectively. Moreover, between the inner peripheral surface of the cylinder 11 and the outer peripheral surfaces of the piston heads 15a and 15b, first and second annular flow channels 17a and 17b having a predetermined interval are formed. In FIG. 1A, the cylinder 11 and the first and second pistons 14a and 14b are shown in their initial positions.

  The companion plate portion 20 includes an arm 18 (18) extending rearward from the cylinder 11 configured as described above, and a conventionally known companion plate 21 attached to the tip portion thereof.

  Next, the operation of the above embodiment will be described. For example, a viscoelastic fluid such as an elastomer is sealed in the cylinder 11 while being pressurized to a predetermined pressure Po. As shown by arrow A in FIG. 1A, when a leftward external force is applied to the cylinder 11 from the companion plate portion 20, the cylinder portion 11 is left when considered as a fixed portion where the coupler portion 1 does not move. Move in the direction. Then, since the tip of the first piston rod 16a is in contact with the first contact plate 2a, the movement is blocked, but the back surface of the head 15b of the second piston 14b is the second cylinder side wall. It is pushed by 2b and moves to the right. In other words, the tip of the second piston rod 16b is separated from the second contact plate 2b. Such a state is shown in FIG. At this time, since the first piston rod 16a enters the cylinder 11, the volume in the cylinder 11 decreases and the pressure Po further increases. Since the viscoelastic fluid flows from the front side to the back side of the piston head 15a through the first annular channel 17a, a flow resistance is generated, and a differential pressure is generated before and after the piston head 15a. As a result, the pressure of the viscoelastic fluid sealed at the pressure Po changes as P1 on the front side of the piston head 15a and P2 on the back side. That is, it changes as P2 <P1. As a result, a reaction force against the leftward movement of the companion plate portion 20 is generated, and the kinetic energy is converted into thermal energy by the large flow resistance in which the viscoelastic fluid flows through the annular flow path 17a, thereby obtaining a damping characteristic.

  When the external force from the companion plate portion 20 disappears, the pressure P1 on the front side of the first piston head 15a is larger than the pressure P2 on the back side, so that the first piston head 15a tries to push out. Since the tip of the rod 16a is in contact with the first contact plate 2a, it cannot be pushed out, and as a reaction, the cylinder 11 moves to the right. That is, the cylinder 11 returns to the direction of the initial position as follows. First, since the pressure P1 on the front side of the first piston head 15a is larger than the pressure P2 on the back side, a force acts on the first piston head 15a in the left direction, and the cylinder 11 moves in the right direction as a reaction. Movement due to this pressure difference is completed in a short time. By this movement, the viscoelastic fluid in the cylinder 11 on the front side of the first piston head 15a expands and the pressure decreases, and the viscoelastic fluid on the back side compresses and the pressure increases, and the first piston head 15a increases. The first piston head 15a moves to a position where the forces of the viscoelastic fluid acting on both the surfaces of the two are balanced. The cylinder 11 and the first and second pistons 14a and 14b in the moved state are shown in FIG. At this time, since the area of the front surface of the first piston head 15a is larger than the area of the back surface, the pressure P3 on the front surface side of the first piston head 15a is smaller than the pressure P4 on the back surface side, and the magnitude relationship between the pressures is P4> P3. As a result, a differential pressure in the opposite direction is generated between the front side and the back side of the first piston head 15a. Accordingly, the viscoelastic fluid flows from the back side to the front side as indicated by the arrow R ′ in FIG. This flow continues until the back surface of the first piston head 15a comes into contact with the first cylinder side wall 12a, so that the cylinder 11 and the first and second pistons 14a and 14b return to their initial positions. The restored state is shown in FIG. As shown in FIG. 1C, when the cylinder 11 moves in the right direction, the area of the front surface of the second piston head 15b is larger than the area of the back surface. The piston 14b moves in a state where the back surface of the head 15b is pressed against the second cylinder side wall 12b.

  Conversely, in FIG. 1A, when a tensile force is received from the companion plate portion 20, the cylinder 11 moves to the right. As is clear from FIG. 1, the pair of first and second pistons 14a and 14b and the pair of first and second contact plates 2a and 2b are symmetrical with respect to the cylinder 11, and thus operate in the same manner. Dampen or damp and return to the initial position as well. Moreover, since the motion between the connector part 1 and the companion plate part 20 is relative, even if a compressive force or a pulling force is applied from the connector part 1, the connector part 1 and the companion plate are further affected. It acts similarly on the relative compressive force or tension with respect to the portion 20 to attenuate or cushion, and similarly returns to the initial position.

  FIG. 2 shows a shock absorber according to the second embodiment. Alternatively, the principle of the shock absorber is schematically shown. Although not described in detail with reference numerals or letters used in FIG. 1, the cylinder 11 is longer by a predetermined amount in the axial direction than the first embodiment. Alternatively, the first and second piston rods 16a and 16b are elongated in the axial direction by a predetermined amount. That is, as shown in FIG. 2A, in the initial position, between the back surfaces of the first and second piston heads 15a and 15b and the seating surfaces of the first and second cylinder side walls 12a and 12b. The same intervals La and Lb are opened.

  The shock absorber according to the second embodiment operates as follows. That is, a viscoelastic fluid is sealed in the cylinder 11 at a predetermined pressure Po. Due to the difference between the area of the front surface and the area of the back surface of the first and second piston heads 15a and 15b, the first and second pistons 14a and 14b take the positions shown in FIG. As shown by an arrow A in FIG. 2A, when a leftward external force is applied from the companion plate portion 20 to the cylinder 11, the cylinder 11 is considered to be a fixed portion that does not move. Will move to the left. That is, since the internal pressure Po acts on the first and second piston heads 15a and 15b to push them outward, the distal ends of the piston rods 16a and 16b are in the first and second piston heads 15a and 15b. The abutting plates 2a and 2b are in contact with each other to prevent movement, and the cylinder 11 moves. Since the first and second piston rods 16a and 16b go in and out while the cylinder 11 moves through the interval La (Lb), the volume of the cylinder 11 does not change and the pressure Po does not change. The viscoelastic fluid on the front side of the first piston head 15a passes through the first annular channel 17a to the back side, and the viscoelastic fluid on the back side of the second piston head 15b passes through the second annular flow. Each flows through the path 17b to the front side. Kinetic energy is converted into thermal energy by the flow resistance at this time, and a damping characteristic is obtained.

  A state where the cylinder 11 has finished moving the interval La (Lb) is shown in FIG. When the cylinder 11 operates within this interval La (Lb), the pressure Po in the cylinder 11 does not change even if the external force is lost, and therefore the cylinder 11 does not automatically return to the initial position. Since the viscoelastic fluid is compressed, when the external force no longer acts, it only returns to some extent due to its restoring force.

  When an external force is further applied, the second piston head 15b is pressed against the second cylinder side wall 12b and moves with the cylinder 11 beyond the interval La. In other words, the tip of the second piston rod 16b is separated from the second contact plate 2b. Such a separated state is shown in FIG. FIG. 2C shows the same state as that shown in FIG. 1A showing the first embodiment described above. Therefore, the subsequent operation is the same as in the first embodiment. When an external force exceeding the predetermined interval La (Lb) is applied, the original position is restored within the interval La (Lb).

  FIG. 3 shows a first embodiment of the present invention. FIG. 3 shows an embodiment in which the schematic diagram or the principle diagram shown in FIG. 1 is made more concrete. Therefore, elements having the same functions as those shown in FIG. 1 are simply described by adding a dash “′” to the same reference numeral although the name is different. A first clevis 5 'is attached to the left end of the outer cylinder 3'. The first clevis 5 ′ also has the function of the first contact plate 2 a ′. A second contact plate 2b 'is attached to the right end of the outer cylinder 3'.

  A cylinder 11 ′ is provided concentrically inside the outer cylinder 3 ′ thus configured so as to be guided by the outer cylinder 3 ′. Both ends of the cylinder 11 'are sealed with cylinder side walls 12a' and 12b 'made of seals S' and S ', and a second clevis 21' is connected to the right end via a plurality of connecting members 18 '. It is attached. In FIG. 3, reference numeral V indicates an injection hole having a check valve function that encloses a viscoelastic fluid in a pressurized state.

  Since the above embodiment operates in substantially the same manner as the embodiment of FIG. 1, the operation will be briefly described. A viscoelastic fluid made of an elastomer is sealed in the cylinder 11 'while being pressurized to a predetermined pressure. As indicated by arrow A ′ in FIG. 3A, when a left external force is applied from the second clevis 21 ′ to the cylinder 11 ′, the first clevis 5 ′ does not move and Considering, the cylinder 11 'moves to the left. Then, since the tip of the first piston rod 16a ′ is in contact with the first clevis 5 ′, that is, the first contact plate 2a ′, the movement is prevented, but the second piston 14b ′ is The head 15b 'is pressed against the second cylinder side wall 2b' and moves to the left. In other words, the tip of the second piston rod 16b 'is separated from the second contact plate 2b'. Such a state is shown in FIG. At this time, since the first piston rod 16a 'enters the cylinder 11', the apparent volume of the cylinder 11 'decreases and the pressure further increases. Since the pressure increases, the reaction force and the damping effect are increased. Since the viscoelastic fluid flows from the front side to the back side of the first piston head 15a 'through the first annular channel 17a', a flow resistance is generated, and a differential pressure is generated before and after the piston head 15a '. As a result, the pressure on the front side of the piston head 15a 'of the viscoelastic fluid becomes higher than the pressure on the back side. As a result, a reaction force against the leftward movement of the second clevil 21 ′ is generated, and the kinetic energy is converted into thermal energy by the large flow resistance of the viscoelastic fluid flowing through the annular flow path 17a ′, thereby obtaining a damping characteristic. .

  When the external force from the second clevis 21 ′ disappears, the pressure on the front side of the first piston head 15 a ′ is greater than the pressure on the back side, so that the first piston head 15 a ′ is pushed out. Since the tip of the rod 16a 'is in contact with the first clevis 5', that is, the first contact plate 2a ', it cannot be pushed out, and as a reaction, the cylinder 11' moves to the right. . That is, the cylinder 11 'returns to the initial position. At this time, since the cylinder 11 ′ moves to the right, the viscoelastic fluid in the cylinder 11 ′ on the front side of the first piston head 15a ′ expands and the pressure decreases, and the viscoelastic fluid on the back side compresses. Then, it moves up and instantaneously moves so that the force acting on the first piston head 15a 'becomes equal. In this state, since the area of the front surface of the first piston head 15a 'is larger than the area of the rear surface, the pressure on the front surface side of the first piston head 15a' is smaller than the pressure on the rear surface side. As a result, a differential pressure in the opposite direction is generated between the front side and the back side of the first piston head 15a '. Therefore, the viscoelastic fluid flows from the back side to the front side. This flow continues until the back surface of the first piston head 15a ′ contacts the first cylinder side wall 12a ′, so that the cylinder 11 ′ and the first and second pistons 14a ′ and 14b ′ return to the initial positions. . When the cylinder 11 ′ moves to the right, the area of the front surface of the second piston head 15b ′ is larger than the area of the back surface, so that the second piston 14b ′ has a back surface of the head 15b ′. It moves while being pressed against the second cylinder side wall 12b.

  In contrast, when a pulling force is received from the second clevis 21 ', the cylinder 11' moves rightward. As apparent from FIG. 3, the pair of first and second pistons 14a ′ and 14b ′ and the first and second contact plates 2a ′ and 2b ′ are symmetrical with respect to the cylinder 11 ′. Acts to damp or damp and return to the initial position as well. In addition, since the movement between the first and second clevises 5 ′ and 21 ′ is relative, even if a compressive force or a pulling force is applied from the first clevis 5 ′, the first clevis 5 It acts similarly on the relative compressive force or tension between 'and the second clevis 21' to damp or damp and similarly return to the initial position.

  It should be noted that the embodiment in which the schematic diagram or the principle diagram shown in FIG. 2 is made more specific is not particularly shown because it is easily understood by those skilled in the art.

1 connecting portion 2a, 2b first and second contact plates
10 buffer base 11 cylinder 12a, 12b first and second cylinder side walls
14a, 14b First and second pistons 15a, 15b First and second piston heads 16a, 16b First and second piston rods
20 companion board 21 companion board

Claims (3)

A first member (1) having a pair of contact portions (2a, 2b) arranged at a predetermined interval and a second member provided between the pair of contact portions (2a, 2b) (10) comprising a shock absorber for attenuating vibrations / impacts caused by a change in external force acting between the first and second members,
The second member (10) is a pair of cylinders (11) having cylinder side walls (12a, 12b) at both ends and piston heads (15a, 15b) facing each other inside the cylinder. The first and second pistons (14a, 14b)
Between the inner peripheral surface of the cylinder (11) and the outer peripheral surfaces of the first and second piston heads (15a, 15b), there is a predetermined interval at which the viscoelastic fluid sealed inside with a predetermined pressure flows. Annular passages (17a, 17b) are formed, and the piston rods (16a, 16b) of the pistons (14a, 14b) exit from the cylinder side walls (12a, 12b) to the outside, and The tip of the head (15a, 15b) is in contact with the pair of contact portions (2a, 2b) while the back surface of the head (15a, 15b) is in contact with the cylinder side wall (12a, 12b). A shock absorber filled with a viscoelastic fluid. A first member (1) having a pair of contact portions (2a, 2b) arranged at a predetermined interval and a second member provided between the pair of contact portions (2a, 2b) (10) comprising a shock absorber for attenuating vibrations / impacts caused by a change in external force acting between the first and second members,
The second member (10) is a pair of cylinders (11) having cylinder side walls (12a, 12b) at both ends and piston heads (15a, 15b) facing each other inside the cylinder. The first and second pistons (14a, 14b)
Between the inner peripheral surface of the cylinder (11) and the outer peripheral surfaces of the first and second piston heads (15a, 15b), there is a predetermined interval at which the viscoelastic fluid sealed inside with a predetermined pressure flows. Annular passages (17a, 17b) are formed, and the piston rods (16a, 16b) of the pistons (14a, 14b) exit from the cylinder side walls (12a, 12b) to the outside, and With the back surfaces of the heads (15a, 15b) being separated from the cylinder side walls (12a, 12b) by a predetermined distance (La, Lb), the tip portions thereof are in contact with the pair of contact portions (2a, 2b). A shock absorber in which a viscoelastic fluid is sealed, which is in contact with each other. 3. The shock absorber according to claim 1, wherein the first member and the second member are applied to a connector device of a railway vehicle. The shock absorber encloses a viscoelastic fluid.

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