JP2015224689A - Gas spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas spring capable of preventing entry of foreign objects.SOLUTION: A gas spring 100 generates a restoring force against an external force applied in a tensile direction and includes: a piston rod 30 which is connected with a piston 20 and protrudes from a tip of a cylinder 10 to be connected with the other side; a bracket 50 which connects a base end of the cylinder 10 with the other side; a gas chamber 11 filled with a high pressure gas; an atmospheric chamber 12 which is defined by the cylinder 10, the piston 20, and the bracket 50; a ventilation passage 60 which is formed in the bracket 50 and allows the atmospheric chamber 12 and the exterior side of the bracket 50 to communicate with each other; and a filter 70 which is disposed in the ventilation passage 60 and filters air flowing into the atmospheric chamber 12.

Description

  The present invention relates to a gas spring that generates a restoring force against an external force in a tensile direction.

  Patent Document 1 discloses a gas spring in which a gas chamber and an atmospheric pressure chamber are defined by a piston in a cylinder, and the piston rod is biased in a direction in which the piston rod is pulled into the cylinder by the gas pressure in the gas chamber.

  In the gas spring, a vent hole penetrating the end of the cylinder is formed, and the atmospheric pressure chamber communicates with the outside of the cylinder through the vent hole.

  When the gas spring contracts, the atmospheric pressure chamber contracts, and the air in the atmospheric pressure chamber flows out to the outside through the vent hole. On the other hand, when the gas spring extends, the atmospheric pressure chamber expands and air from the outside flows into the atmospheric pressure chamber through the vent hole.

Japanese Patent Laid-Open No. 7-139571

  However, in such a conventional gas spring, since the vent hole is formed through the end of the cylinder, foreign matters such as dust enter the cylinder through the vent hole from the outside of the cylinder, resulting in malfunction. There is a problem of inviting.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a gas spring that can prevent entry of foreign matter.

  The present invention is a gas spring that generates a restoring force with respect to an external force in a tensile direction, a cylindrical cylinder, a piston that is slidably inserted into the cylinder, a piston coupled to the piston, and protruding from the tip of the cylinder. A piston rod connected to the opposite side, a bracket connecting the base end of the cylinder to the opposite side, a gas chamber defined by the cylinder, the piston and the piston rod and filled with high pressure gas, a cylinder, a piston, And an air chamber defined by the bracket, an air passage formed in the bracket and communicating the air chamber and the outside of the bracket, and a filter that is interposed in the air passage and filters air flowing into the air chamber. It is characterized by providing.

  In the present invention, when the gas spring extends, air from the outside flows into the expanding atmospheric chamber through the air passage. At this time, the air passing through the air passage is filtered by the filter, so that foreign matter contained in the air is prevented from entering the atmospheric chamber, and the state in which the gas spring operates smoothly is maintained.

It is a perspective view of a sheet concerning an embodiment of the present invention. It is sectional drawing which shows the whole gas spring which concerns on embodiment of this invention. It is sectional drawing which shows a part of gas spring which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a passenger seat 90 (chair) mounted on a train or the like. The seat 90 includes a seating surface 91 on which a seated person sits, and a legrest 92 on which the seated person's legs are placed.

  The leg rest 92 is rotatably supported by a shaft (not shown) provided on the seat 90, and a retracted position extending forward from the front end of the seat surface 91 and a storage extending downward from the front end of the seat surface 91 as illustrated. The rotation position can be changed between the positions.

  Below the seat surface 91, an electric actuator 93 that rotates the legrest 92 and a gas spring 100 that urges the legrest 92 in a direction to retract the legrest 92 from the deployed position to the retracted position are provided. As will be described later, the gas spring 100 generates a restoring force against an external force in the tensile direction.

  The electric actuator 93 expands and contracts when an electric motor (not shown) rotates in both forward and reverse directions by operating a switch (not shown), and rotates the legrest 92 between the deployed position and the retracted position.

  The electric actuator 93 includes an electromagnetic clutch (not shown) that interrupts the driving force of the electric motor. In a state where the legrest 92 is in the deployed position, when the electromagnetic clutch is actuated by operating a switch (not shown) and the driving force of the electric motor is disconnected, the legrest 92 is moved to the retracted position by the restoring force of the gas spring 100. It turns quickly.

  Next, a specific configuration of the gas spring 100 will be described.

  FIG. 2 is a cross-sectional view showing the gas spring 100. The gas spring 100 connects a cylindrical cylinder 10, a piston 20 slidably inserted into the cylinder 10, a piston rod 30 protruding from the tip of the cylinder 10, and a tip of the piston rod 30 to the other side. A rod-side bracket 35 and a bracket 50 that connects the base end of the cylinder 10 to the mating side.

  The rod side bracket 35 is coupled to the tip of the piston rod 30, and is connected to the frame (not shown) of the leg rest 92 via a connecting shaft (not shown) as the other side. The bracket 50 is coupled to the base end of the cylinder 10 and is coupled to the frame (not shown) of the seat 90 via the coupling shaft 9 as a counterpart. As a result, as the legrest 92 rotates between the deployed position and the retracted position, the gas spring 100 is expanded and contracted with respect to the cylinder 10 as the piston rod 30 moves in the axial direction. The “axial direction” means a direction in which the central axis O of the cylinder 10 and the piston rod 30 extends.

  The cylinder 10, the piston 20, the piston rod 30, and the bracket 50 are each formed of a metal material.

  The inside of the cylinder 10 is partitioned into a gas chamber 11 and an atmospheric chamber 12 by a piston 20.

  A bearing 15 is coupled to the tip of the cylinder 10. The piston rod 30 is slidably supported by the bearing 15. The gas chamber 11 is defined by the cylinder 10, the bearing 15, the piston 20, and the piston rod 30.

  The piston rod 30 has a filling hole 31 that extends in the axial direction and communicates with the gas chamber 11. When the gas spring 100 is manufactured, a predetermined amount of oil (lubricating oil) and high-pressure gas (nitrogen gas) are filled into the gas chamber 11 through the filling hole 31, and then the filling hole 31 is sealed by the plug 32.

  Inside the cylinder 10, a packing 16 and an oil chamber assembly 17 are interposed along with the bearing 15, and these are in sliding contact with the outer periphery of the piston rod 30. The gas chamber 11 is sealed with a packing 16. Oil is guided to the piston rod 30 by the oil chamber assembly 17. A dust seal 18 is interposed at the tip of the cylinder 10 along with the bearing 15, and foreign matter attached to the piston rod 30 is scraped off by the dust seal 18.

  A dust seal 21, a wear ring 22, an O ring 23, a backup ring 24, and a wear ring 25 are interposed on the outer periphery of the piston 20, and these are in sliding contact with the inner periphery of the cylinder 10. The dust seal 21 scrapes off foreign matter adhering to the inner periphery of the cylinder 10. Wear rings 22 and 25 slidably support piston 20 with respect to cylinder 10. The gas chamber 11 is sealed with an O-ring 23.

  The proximal end side opening of the cylinder 10 is sealed by the bracket 50. The atmosphere chamber 12 is defined by the cylinder 10, the piston 20, and the bracket 50.

  The bracket 50 includes a columnar coupling portion 51 that is inserted into the proximal end portion of the cylinder 10 and a connecting portion 52 that protrudes in the axial direction of the cylinder 10.

  An annular groove 53 is formed on the outer periphery of the coupling portion 51, and the annular groove 53 is crimped so that a part of the cylinder 10 enters.

  An annular groove 54 is formed on the outer periphery of the coupling portion 51 along with the annular groove 53, and an O-ring 26 is interposed in the annular groove 54. The O-ring 26 seals between the coupling portion 51 and the cylinder 10.

  A connecting hole 55 into which the connecting shaft (pin) 9 is inserted is formed in the connecting portion 52. The connection hole 55 is formed to extend in a direction orthogonal to the central axis O of the cylinder 10. The bracket 50 is rotatably connected to a frame (not shown) of the leg rest 92 via the connecting shaft 9.

  An air passage 60 is formed inside the bracket 50, and the air chamber 12 communicates with the outside of the bracket 50 through the air passage 60.

  A filter 70 is interposed in the ventilation path 60, and the air flowing into the atmosphere chamber 12 is filtered by the filter 70.

  FIG. 3 is an enlarged cross-sectional view of a part of FIG. The bracket 50 is formed with a recess 59 that opens to an end surface facing the atmosphere chamber 12 and a communication hole 56 that extends in the axial direction. One end of the communication hole 56 opens in the center of the recess 59, and the other end opens in the middle of the connection hole 55.

  In a state where the connecting shaft 9 is inserted into the connecting hole 55, the gap 8 is defined between the connecting hole 55 and the connecting shaft 9. In this state, the air passage 60 is defined by the gap 8 and the communication hole 56 in the connection hole 55.

  The filter 70 is accommodated in the coupling portion 51 that is inserted into the cylinder 10 in the bracket 50. The communication hole 56 has an enlarged diameter portion 56A that opens to the recess 59, and a filter 70 is interposed in the enlarged diameter portion 56A. The filter 70 is attached to an annular filter frame 71, and the outer periphery of the filter frame 71 is caulked and fixed to the enlarged diameter portion 56A. At the time of manufacturing the gas spring 100, after the filter 70 is attached to the bracket 50, the bracket 50 is assembled to the cylinder 10.

  The filter 70 is made of a wire mesh having a mesh of a predetermined size, and collects foreign matter that has entered the air passage 60. The filter 70 is not limited to this, and a filter made of resin may be used.

  Next, the operation of the gas spring 100 will be described.

  In the passenger seat 90 shown in FIG. 1, when the legrest 92 is switched from the retracted position to the deployed position, the electric actuator 93 is extended to rotate the legrest 92. Along with this, the gas spring 100 is extended and the gas chamber 11 contracts, while the atmospheric chamber 12 expands. At this time, air from the outside flows into the atmosphere chamber 12 that expands as shown by an arrow in FIG. 3, so that negative pressure is prevented from being generated in the atmosphere chamber 12.

  When the gas spring 100 extends, the air flowing into the atmosphere chamber 12 is taken in from the gap 8 between the connection hole 55 and the connection shaft 9, and foreign matter is prevented from entering the gap 8 having a small opening width. The foreign matter that has entered the communication hole 56 through the gap 8 is collected by the filter 70, and the foreign matter is prevented from entering the atmospheric chamber 12.

  In the passenger seat 90, when the leg rest 92 is switched from the deployed position to the retracted position, the gas spring 100 is contracted by the piston 20 being moved by the pressure (restoring force) of the gas chamber 11. The air in the atmosphere chamber 12 that contracts at this time flows out of the gas spring 100 through the ventilation path 60. As a result, the gas spring 100 quickly contracts.

  The grease applied to the outer periphery of the piston 20 starts to melt, and oil may accumulate in the atmosphere chamber 12. In this case, the O-ring 26 seals between the cylinder 10 and the bracket 50, thereby preventing oil accumulated in the cylinder 10 from leaking out of the cylinder 10. As shown in FIG. 1, in a state where the gas spring 100 is mounted so as to extend in the horizontal direction, the communication hole 56 disposed on the central axis O of the cylinder 10 is separated from the oil accumulated in the lower part of the cylinder 10. Therefore, the oil accumulated in the cylinder 10 is prevented from leaking to the outside of the bracket 50 through the air passage 60. On the other hand, when a hole penetrating the cylinder 10 is formed as a ventilation path as in the conventional device, there is a concern that oil accumulated in the cylinder 10 leaks out of the cylinder 10 through the hole.

  According to the above embodiment, there exists an effect shown below.

  The gas spring 100 is interposed in the ventilation path 60, a bracket 50 that connects the base end of the cylinder 10 to the other side, a ventilation path 60 that is formed in the bracket 50 and communicates the atmosphere chamber 12 and the outside of the bracket 50. And a filter 70 for filtering air flowing into the atmosphere chamber 12.

  Based on the above configuration, when the gas spring 100 extends, air from the outside flows into the atmospheric chamber 12 that expands through the ventilation path 60. The air passing through the air passage 60 is filtered by the filter 70, so that foreign matter contained in the air is prevented from entering the atmosphere chamber 12, and the state in which the gas spring 100 operates smoothly is maintained.

  Since the filter 70 is interposed in the ventilation path 60 formed in the bracket 50, an installation space for the filter 70 is provided in the bracket 50. As a result, the filter 70 is not provided protruding from the outside of the cylinder 10, and the filter 70 can prevent the gas spring 100 from increasing in size. On the other hand, when a hole penetrating the cylinder 10 is formed as a ventilation path as in the conventional apparatus, it is necessary to provide a filter outside the cylinder 10, and the gas spring 100 is enlarged by the filter protruding from the cylinder 10. To do.

  The ventilation path 60 includes a connection hole 55 into which the connection shaft 9 connected to the other side is inserted, and a communication hole 56 that connects the inside of the connection hole 55 and the atmosphere chamber 12. The filter 70 is interposed in the communication hole 56.

  Based on the above configuration, when the gas spring 100 extends, the air flowing into the atmosphere chamber 12 is taken in from the gap 8 defined between the connection hole 55 and the connection shaft 9, and is formed by the gap 8 having a small opening width. Foreign matter is removed. The air passing through the air passage 60 passes through the gap 8 and the filter 70 in order and is filtered in two stages, thereby enhancing the effect of preventing foreign matter from entering the atmosphere chamber 12.

  When assembling the gas spring 100 to be connected to the other side, foreign matter in the connection hole 55 may enter the communication hole 56. Further, the inner peripheral surface of the connection hole 55 is scraped off by the edge of the connection shaft 9 or the like, and a shaving piece is generated. Also in these cases, the filter 70 prevents foreign matter from entering the atmospheric chamber 12.

  Further, the gas spring 100 is provided below the seat surface 91 of the seat 90 on which the seated person sits, and is biased in a direction in which the legrest 92 that supports the leg of the seated person is retracted.

  Based on the above configuration, dust that accumulates below the seat surface 91 is prevented from entering the atmosphere chamber 12 of the gas spring 100 that expands and contracts below the seat surface 91, and the state in which the gas spring 100 operates smoothly is maintained. Is done.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, in the above embodiment, the bracket 50 is formed separately from the cylinder 10. Not limited to this, the bracket may be formed integrally with the cylinder.

  The gas spring of the present invention is not limited to a passenger seat, and may be used for other machines and equipment.

DESCRIPTION OF SYMBOLS 11 Gas chamber 12 Air | atmosphere chamber 20 Piston 30 Piston rod 50 Bracket 55 Connection hole 56 Communication hole 60 Air passage 70 Filter 90 Seat 91 Seat surface 92 Leg rest 100 Gas spring

Claims (3)

A gas spring that generates a restoring force against an external force in the tensile direction,
A cylindrical cylinder;
A piston slidably inserted into the cylinder;
A piston rod coupled to the piston, protruding from the tip of the cylinder and coupled to the other side;
A bracket for connecting the base end of the cylinder to the other side;
A gas chamber defined by the cylinder, the piston, and the piston rod, and filled with high pressure gas;
An atmospheric chamber defined by the cylinder, the piston, and the bracket;
An air passage that is formed in the bracket and communicates between the atmosphere chamber and the outside of the bracket;
A gas spring comprising: a filter interposed in the ventilation path and filtering air flowing into the atmosphere chamber. The air passage is
A connecting hole into which a connecting shaft connected to the other side is inserted;
A communication hole communicating the inside of the connection hole and the atmosphere chamber,
The gas spring according to claim 1, wherein the filter is interposed in the communication hole.   3. The gas spring according to claim 1, wherein the gas spring is provided below a seating surface of a seat on which a seated person sits and biases the legrest that supports a leg of the seated person in a retracting direction. gas spring.

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