JP2009264500A - Gas spring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas spring device having good cushioning performance at a set position in all stroke region of a cylinder for a piston. <P>SOLUTION: The gas spring device 1 includes the piston 10 provided movably relative to a piston rod 11, and an elastic body 14 (an energizing means) provided between the piston 10 and the piston rod 11 for energizing the piston 10 in the direction of leaving the piston rod 11. Thus, it has good cushioning performance at the set position in all stroke region of the cylinder 5 for the piston 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas spring device used for a height adjusting mechanism such as a chair.

In general, the gas spring device is used for a height adjustment mechanism of a chair or the like. However, in the conventional gas spring device, the user operates the operation lever and extends the gas spring device while lifting the waist, and the seat portion. The seat portion of the chair is set to a desired height by raising the weight or by shortening the gas spring device while applying weight and lowering the seat portion.
However, in the conventional gas spring device, after the seat portion is set to a desired height, that is, after the axial position of the cylinder is set with respect to the piston, the cylinder is locked with respect to the piston. Therefore, cushioning is ensured only by compression of the gas in the cylinder. Therefore, when seated, there was a need to improve cushioning properties because the cushioning properties were small.

As a prior art of the gas spring device, Patent Document 1 includes a spring in the second partial space above the piston, and when the second partial space reaches the minimum length due to the displacement of the piston, the spring is attached to the valve. A length adjustable gas spring located on the sealing surface is disclosed.
JP 2000-35074 A

As described above, in the conventional gas spring device, the cylinder is locked with respect to the piston after the axial position of the cylinder is set with respect to the piston. It was impossible to obtain cushioning properties.
Further, in the gas spring according to the invention of Patent Document 1, the elasticity by the spring is obtained when the outer cylinder slides downward with respect to the piston, but the set position in the entire stroke region with respect to the piston of the outer cylinder (cylinder). It was impossible to obtain a good cushioning property.

  This invention is made | formed in view of this point, and it aims at providing the gas spring apparatus which can acquire favorable cushioning property in the setting position in the full stroke area | region with respect to the piston of a cylinder.

  As means for solving the above-mentioned problems, the invention described in claim 1 of the present invention is such that a piston is provided so as to be movable in the axial direction of the piston rod with respect to the piston rod, and between the piston and the piston rod. And an urging means for urging the piston in a direction away from the piston rod.

  According to the gas spring device of the present invention, good cushioning properties can be obtained at the set position in the entire stroke region with respect to the piston of the cylinder.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.
The gas spring devices 1 and 1a according to the first and second embodiments of the present invention are attached between a seat portion 2a and a leg portion 2b of a chair 2, as shown in FIGS. , A cylinder 5 filled with compressed gas, and a piston 10 that slides in a cylinder chamber 8 in the cylinder 5 and defines the cylinder chamber 8 into two chambers, an upper cylinder chamber 6 and a lower cylinder chamber 7. A piston rod 11 having an upper end connected to the piston 10 and a lower end extending from the cylinder 5, an annular passage (passage) 12 communicating the upper cylinder chamber 6 and the lower cylinder chamber 7, and the annular passage An elastic body 14 or a gas 15 (attached) is provided between the lock mechanism 13 for communicating / blocking 12 and the upper end of the piston 10 and the piston rod 11 and urges the piston 10 away from the piston rod 11. Force It is equipped with a stage) and.
In the gas spring devices 1, 1 a according to the first and second embodiments of the present invention, the arrangement of the biasing means made of the elastic body 14 or the gas 15 is between the piston 10 and the upper end of the piston rod 11. In other words, the piston 10 is connected to the upper end of the piston rod 11 via the biasing means.

First, the gas spring device 1 according to the first embodiment of the present invention will be described in detail based on FIGS. 1 and 2 with reference to FIG.
As shown in FIG. 1, the gas spring device 1 according to the first embodiment forms an outer cylinder 16 extending in the axial direction and a double cylinder with an annular gap formed inside the outer cylinder 16. A cylinder 5 inserted into the cylinder 5, a piston rod 11 inserted into the cylinder 5 from below the outer cylinder 16 and having a lower end extending from the cylinder 5, and an elastic body 14 (biasing means) at the upper end of the piston rod 11. ) And is slidable in the cylinder chamber 8 so as to be movable in the axial direction of the piston rod 11 with respect to the piston rod 11, and the cylinder chamber 8 is divided into the upper cylinder chamber 6 and the lower cylinder chamber 7. A piston 10 that is formed, a lock mechanism 13 that is provided at an upper portion in the outer cylinder 16 and that communicates and blocks between the upper cylinder chamber 6 and the lower cylinder chamber 7, and a cylindrical valve body that constitutes the lock mechanism 13 Tubular guy in 25 An operation plug 19 that is in contact with the valve rod 18 inserted into the central hole 17 of the member 41, and a rod that fits the lower end inner peripheral surface of the outer cylinder 16 and guides the piston rod 11 so as to be slidable in the axial direction. And a guide 20.

As shown in FIG. 4, the outer cylinder 16 is attached to a frame (not shown) in which the upper part is horizontally mounted on the lower side of the seat 2 a of the chair 2. As shown in FIG. 1, an annular step portion 21 for locking the lock mechanism 13 is provided on the upper inner peripheral surface of the outer cylinder 16. At the lower end of the outer cylinder 16, an annular locking portion 22 that prevents the rod guide 20 from falling off is projected inward.
As shown in FIG. 4, on the outer side of the outer cylinder 16, there is a large-diameter tube 23 that extends downward from a substantially half position in the axial direction and is fitted to the intersecting portion of each leg 2 b of the chair 2. It is covered. Further, a guide bush (not shown) is interposed between the outer cylinder 16 and the large diameter tube 23.

  As shown in FIG. 1, the cylinder 5 is held between the lock mechanism 13 and the lock guide 20 so as to form an annular gap inside the outer cylinder 16. The cylinder chamber 8 in the cylinder 5 is defined by the piston 10 into an upper cylinder chamber 6 and a lower cylinder chamber 7. An annular gap provided between the inner peripheral surface of the outer cylinder 16 and the outer peripheral surface of the cylinder 5 functions as an annular passage 12 that communicates between the upper cylinder chamber 6 and the lower cylinder chamber 7. The annular passage 12 has an upper end communicating with a communication hole 26 provided in the cylindrical valve body 25 of the lock mechanism 13 and a lower end communicating with a communication hole 27 provided in the rod guide 20. The cylinder chamber 8 is filled with compressed gas (for example, nitrogen gas).

  As shown in FIG. 1, the piston rod 11 is guided from below the outer cylinder 16 to the rod guide 20 and inserted into the cylinder chamber 8 of the cylinder 5. On the outer peripheral surface of the upper end portion of the piston rod 11, an annular recess 28 having a diameter reduced in a predetermined range in the axial direction is formed. The lower end of the piston rod 11 extends from the lower side of the outer cylinder 16 and is fixed to the bottom of the large diameter tube 23 shown in FIG.

  As shown in FIG. 1, the piston 10 is provided with a piston lower portion 29 supported in an axially movable manner in an annular recess 28 provided in the upper portion of the piston rod 11, and a hole portion 30 for accommodating the piston lower portion 29. The piston upper part 33 is comprised.

  As shown in FIG. 1, the piston lower portion 29 is formed in a cylindrical shape that moves in the axial direction in the annular recess 28 of the piston rod 11. The outer diameter of the piston lower portion 29 coincides with the inner diameter of the hole 30 of the piston upper portion 33.

As shown in FIG. 1, the piston upper portion 33 is located below the piston large diameter portion 33 a, which is in sliding contact with the inner peripheral surface of the cylinder 5, and its outer peripheral surface is the same as the inner peripheral surface of the cylinder 5. And a small piston diameter portion 33b that forms a gap therebetween.
On the outer peripheral surface of the piston large diameter portion 33 a of the piston upper portion 33, a seal member 36 composed of an O-ring that slides in contact with the inner peripheral surface of the cylinder 5 is attached.
A plurality of pressure increase prevention holes 35 penetrating in the radial direction are formed in the piston small diameter portion 33 b of the piston upper portion 33. Each pressure-increasing prevention hole 35 accommodates the piston lower portion 29 in the hole portion 30 of the piston upper portion 33 so that the lower end of the piston lower portion 29 substantially coincides with the lower end of the piston upper portion 33 than the upper surface of the piston lower portion 29. It is formed so as to be located above.
The depth of the hole 30 of the piston upper portion 33 is formed to a depth that allows the elastic body 14 to be described later to be accommodated in the hole 30 in a state where the piston lower portion 29 is accommodated in the hole 30 as described above. The depth thereof substantially matches the axial length of the piston small diameter portion 33b of the piston upper portion 33.

The piston 10 accommodates the piston lower portion 29 in the hole 30 of the piston upper portion 33 and is arranged so that the lower end of the piston lower portion 29 substantially coincides with the lower end of the piston upper portion 33. The piston upper portion 33 and the piston lower portion 29 are caulked and joined by pressing the lower outer peripheral surface of the portion 33b.
Further, as shown in FIG. 1, the piston lower portion 29 is supported in the annular recess 28 at the upper end portion of the piston rod 11 so as to be movable in the axial direction, and the upper end surface of the piston rod 11 and the hole portion 30 in the piston upper portion 33. An elastic body (biasing means) 14 that urges the piston 10 in a direction away from the piston rod 11 is disposed in a space between the bottom surface of the piston rod 11 and the piston rod 11. The elastic body 14 is made of urethane rubber, a metal spring, or the like.
Thereby, the piston 10 is configured to be movable in a predetermined range (range A shown in FIG. 2) in the axial direction via the elastic body 14 with respect to the piston rod 11.

As shown in FIG. 1, the locking mechanism 13 has a cylindrical shape in which an annular taper surface 37 whose chamfered upper end is in contact with the annular step portion 21 of the outer cylinder 16 and a lower outer peripheral surface is in contact with the inner peripheral surface of the cylinder 5. A valve body 25, a valve rod 18 having a plate-like valve member 47 at its lower end, slidably inserted into a central hole 17 of a tubular guide member 41 provided in the valve hole of the tubular valve body 25, The diameter of the tubular valve body 25 so that the central hole 17 of the tubular guide member 41 in the tubular valve body 25 communicates with the annular passage 12 (between the inner peripheral surface of the outer tube 16 and the outer peripheral surface of the cylinder 5). It is comprised roughly from the communicating hole 26 provided in the direction.
The tubular valve body 25 is formed with an annular tapered surface 37 having a chamfered outer periphery at the upper end, and the annular tapered surface 37 is brought into contact with the annular locking portion 21 provided on the inner circumferential surface of the outer cylinder 16. The valve hole of the tubular valve body 25 is composed of a small diameter valve hole 38 and a large diameter valve hole 39 from the upper side. The large diameter valve hole 39 of the cylindrical valve body 25 is provided with a cylindrical guide member 41 having a central hole 17 into which the valve rod 18 is inserted. A concave portion 40 having a diameter larger than that of the large diameter valve hole 39 is formed on the lower surface of the tubular valve body 25. The concave portion 40 of the tubular valve body 25 is provided with a plate-shaped valve seat 43 on which a plate-shaped valve member 47 provided at the lower end of the valve rod 18 is seated. The central hole 17 of the cylindrical guide member 41 is communicated with a communication hole 26 provided in the cylindrical valve body 25 through a small hole 42 penetrating in the radial direction of the cylindrical guide member 41.

The cylindrical valve body 25 includes a sealing member 50 formed of an O-ring that contacts and seals the inner peripheral surface of the outer cylinder 16 and an O-ring that contacts and seals the inner peripheral surface of the cylinder 5. A seal member 51 made of a ring is attached to each. The large-diameter valve hole 39 of the cylindrical valve body 25 has sealing members 52 and 52 formed of O-rings that slide in contact with the outer peripheral surface of the shaft portion 45 of the valve rod 18 above and below the cylindrical guide member 41. Are installed respectively.
As shown in FIG. 1, the valve stem 18 includes a shaft portion 45 inserted into the small-diameter valve hole 38 of the tubular valve body 25 and the central hole 17 of the tubular guide member 41, and an intermediate portion of the shaft portion 45 in the axial direction. It comprises a small-diameter shaft portion 46 that is reduced in diameter in the radial direction provided at the part, and a plate-like valve member 47 that is provided at the lower end of the shaft portion 45.

  As shown in FIG. 1, the lower end of the operation plug 19 is in contact with the upper end of the valve stem 18, and an operation lever (not shown) disposed below the seat 2a of the chair 2 shown in FIG. By operating it, the valve stem 18 is moved in the axial direction.

As shown in FIG. 1, the rod guide 20 is fitted to the inner peripheral surface of the lower end of the outer cylinder 16 and is locked to an annular locking portion 22 provided on the outer cylinder 16, so that the piston rod 11 is moved in the axial direction. The guide is slidable. In the upper part of the rod guide 20, a plurality of communication holes 27 that communicate the annular passage 12 provided between the inner peripheral surface of the outer cylinder 16 and the outer peripheral surface of the cylinder 5 and the lower cylinder chamber 7 of the cylinder chamber 8. Is formed.
A seal member 56 made of an O-ring that contacts and seals the inner peripheral surface of the outer cylinder 16 is attached to the lower outer peripheral surface of the rod guide 20.

Next, the operation of the gas spring device 1 according to the first embodiment will be described.
When the height of the seat 2a of the chair 2 is adjusted, if the user operates the operation lever while the waist is lifted from the seat 2a, the operation plug 19 pushes down the valve rod 18 of the lock mechanism 13.
Then, the plate-like valve member 47 at the lower end of the valve stem 18 is separated from the plate-like valve seat 43 of the tubular valve body 25, and the small-diameter shaft portion 46 of the valve stem 18 is sealed below the tubular guide member 41. When the position of the member 52 is reached, the valve is opened.
As a result, the upper cylinder chamber 6 and the lower cylinder chamber 7 of the cylinder chamber 8 are connected to the central hole 17 and the small hole 42 of the cylindrical guide member 41, the communication hole 26 of the cylindrical valve body 25, the annular passage 12, and the rod guide. Communicating through the 20 communication holes 27, compressed gas can flow between the upper cylinder chamber 6 and the lower cylinder chamber 7, and the outer cylinder 16 can slide upward or downward with respect to the piston 10. .

When the user raises or lowers the seat 2a to an arbitrary height, the user floats the waist from the seat 2a while operating the operation lever, or the waist sits on the seat 2a. The seat portion 2a is set to a desired height by sliding the outer cylinder 16 (cylinder 5) upward or downward with respect to the piston 10.
Thereafter, when the operation lever is returned to the original position when the seat portion 2a is set to a desired height, the plate-like valve member 47 at the lower end of the valve rod 18 is biased upward by the compressed gas in the upper cylinder chamber 6. Then, the lock mechanism 13 is closed.
As a result, the communication between the upper cylinder chamber 6 and the lower cylinder chamber 7 is blocked, so that the position of the outer cylinder 16 (cylinder 5) relative to the piston 10 is maintained, and the position of the seat portion 2a at a predetermined height is maintained. Retained.

In FIG. 2, the left side in the figure with respect to the center line shows the no-load state with respect to the gas spring device 1 according to the first embodiment, and the right side in the figure shows the loaded state.
Thereafter, when the user sits down on the seat 2a that has already been set to the desired height, the impact shifts from the state on the left side of the drawing in FIG. 2 to the state on the right side of the drawing, that is, the outer cylinder 16 And the lock mechanism 13 move downward, and the compressed gas in the upper cylinder chamber 6 presses the piston upper portion 33 of the piston 10, so that the piston 10 moves downward relative to the piston rod 11. At the same time, the elastic body 14 is compressed.
When the piston 10 is pressed and the piston 10 moves downward with respect to the piston rod 11, the gas in the space between the upper end surface of the piston rod 11 and the bottom surface of the hole 30 of the piston lower portion 29 is Since each pressure increase prevention hole 35 provided in the piston upper portion 33 is opened to the lower cylinder chamber 7, the elastic body 14 is smoothly compressed.
Thereby, the impact when the user sits down on the seat 2a can be absorbed by the elastic body 14, and good cushioning properties can be obtained.

Next, a gas spring device 1a according to a second embodiment of the present invention will be described in detail with reference to FIG. In FIG. 3, the left side in the figure with respect to the center line shows the no-load state with respect to the gas spring device 1 a according to the second embodiment, and the right side in the figure shows the loaded state.
When describing the gas spring device 1a according to the second embodiment, only differences from the gas spring device 1 according to the first embodiment will be described.

As shown in FIG. 3, a seal member 55 composed of an O-ring that is slidably brought into contact with the outer peripheral surface of the annular recess 28 of the piston rod 11 is attached to the inner peripheral surface of the piston lower portion 29.
The sealing member 55 that is in sliding contact with the outer peripheral surface of the piston rod 11 in the airtight space between the upper end surface of the piston rod 11 and the bottom surface of the hole 30 of the piston upper portion 33, specifically, in the hole portion 30 of the piston lower portion 29. A gas 15 (biasing means) that urges the piston 10 in a direction away from the piston rod 11 is filled in an airtight space above the sealing surface. The gas 15 is a compressed gas (for example, nitrogen gas).

As a result, in the gas spring device 1a according to the second embodiment, when the user sits down on the seat 2a that has already been set to the desired height, the impact from the state on the left side of the drawing in FIG. Transition to the state on the right side of the drawing, that is, the outer cylinder 16 moves downward and the lock mechanism 13 moves downward, and the compressed gas in the upper cylinder chamber 6 presses the piston upper portion 33 of the piston 10, The piston 10 moves downward relative to the piston rod 11 while the pressure of the gas 15 in the airtight space in the hole 30 of the piston lower portion 29 is increased.
As a result, the impact when the user sits down on the seat 2a can be absorbed by the gas 15, and good cushioning properties can be obtained.

As described above, in the gas spring devices 1 and 1a according to the first and second embodiments of the present invention, the piston 10 is provided so as to be movable with respect to the piston rod 11, and between the piston 10 and the piston rod 11 is provided. Further, an elastic body 14 or a gas 15 (biasing means) that urges the piston 10 in a direction away from the piston rod 11 is provided.
Thereby, even when the seat 2a is set at any position in the height direction, the impact when the user sits on the seat 2a can be absorbed by the elastic body 14 or the gas 15, and at the time of sitting A fluffy and good cushioning property can be obtained.
In short, in this gas spring device 1, 1a, a good cushioning property can be obtained at a set position in the entire stroke region with respect to the piston 10 of the cylinder 5.

FIG. 1 is a cross-sectional view showing a gas spring device according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a main part of the gas spring device of FIG. FIG. 3 is an enlarged view of a main part of the gas spring device according to the second embodiment of the present invention, in which the left side in the figure is a no-load state with the center line as the boundary, and the right side in the figure is a load state It is sectional drawing shown. FIG. 4 is an external view in which a gas spring device according to an embodiment of the present invention is attached between a seat portion and a leg portion of a chair.

Explanation of symbols

1, 1a Gas spring device, 5 cylinder, 6 upper cylinder chamber, 7 lower cylinder chamber, 8 cylinder chamber, 10 piston, 11 piston rod, 12 annular passage (passage), 13 lock mechanism, 14 elastic body (biasing means) ), 15 Gas (energizing means)

Claims (3)

A cylinder filled with gas, a piston that slides inside the cylinder and defines the inside of the cylinder in two chambers, a piston rod connected to the piston, and a passage that communicates the defined two chambers And a gas spring device comprising a lock mechanism for communicating and blocking the passage,
The piston is movably provided in the axial direction of the piston rod with respect to the piston rod, and is biased between the piston and the piston rod to bias the piston in a direction away from the piston rod. A gas spring device comprising means.   The gas spring device according to claim 1, wherein the biasing means is an elastic body.   The gas spring device according to claim 1, wherein the urging unit is a gas.

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