JPH07139571A - Gas spring - Google Patents

Abstract

PURPOSE:To contract a piston rod from the maximum extention position to a minimum contraction position with desired speed by providing gas in a cylinder with fluid resistance by means of an orifice. CONSTITUTION:An atmospheric chamber A and a gas chamber B on the side of a piston rod 7 are determined by a piston 4 in a cylinder 1. A valve mechanism 9 is arranged in the atmospheric chamber A to allow atmospheric air to flow into the side of the chamber A, and to prevent occurrence of reversed flow. An orifice 13 is arranging on the valve mechanism 9 for providing atomspheric air discharged from the chamber A with a constant fluid resistance. The piston rod 7 can be extended by external force by the valve mechanism 9 without resistance. When the external force is eliminated, the piston rod 7 is contracted by the gas pressure inside the gas chamber B. In addition, resistance is provided by the boosted atmospheric chamber A. Air in the atmospheric chamber A is discharged through the orifice 13 by a specified rate for gradual contraction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas spring adapted to generate a restoring force in a direction of contracting a piston rod with respect to an external force in a pulling direction when a door or the like is opened or closed.

[0002]

2. Description of the Related Art Generally, a cylinder having one end closed by a bottom cap and a rod guide provided at the other end is slidably fitted into the cylinder, and the inside of the cylinder is divided into two gas chambers. A gas spring composed of a formed piston and a piston rod having one end fixed to the piston and the other end protruding outside the cylinder through the rod guide is known, for example, from Japanese Patent Publication No. 53-3476.

In this type of conventional gas spring, of the gas chambers defined in the cylinder by the piston, the gas chamber on the piston rod side is filled with high pressure gas to form the high pressure gas chamber, and the other gas chamber. A low-pressure gas is filled in to form a low-pressure gas chamber, and the piston rod is contracted into the cylinder by urging the piston from the high-pressure gas chamber toward the low-pressure gas chamber in the cylinder.

When an external force in the pulling direction is applied so as to extend the piston rod to the outside of the cylinder, the high pressure gas chamber located on the piston rod side is pressurized by the piston and becomes a higher pressure state. It can be pressed with a high gas pressure toward the low-pressure gas chamber, and a restoring force can be generated in the direction in which the piston rod is constantly contracted.

[0005]

By the way, in the above-mentioned conventional gas spring, the high pressure gas chamber and the low pressure gas (including atmospheric pressure) chamber in the cylinder are always cut off by a piston or the like, and the piston rod is When expanding and contracting from the cylinder, the volume of the high-pressure gas chamber is changed to generate a restoring force in the contracting direction by the gas pressure of the high-pressure gas chamber. It becomes infinitely large when it is extended, and becomes small when the piston rod is fully contracted. Further, since such a gas spring is not provided with a mechanism for controlling the contraction speed of the piston rod, the contraction speed of the piston rod is determined by the pressure in the high pressure gas chamber. As a result, the contraction speed of the piston rod decreases from the most extended position to the most contracted position, and in particular, at the initial stage of contraction from the most extended position, the piston rod contracts at high speed, and the contraction speed fluctuates greatly. There's a problem.

The present invention has been made in view of the above-mentioned problems of the prior art. In the gas in the cylinder, the flow resistance is hardly given at the time of expansion, and the flow resistance is given by the orifice at the time of reduction, and the piston rod at the time of reduction is provided. It is an object of the present invention to provide a gas spring capable of contracting from the maximum extension position to the minimum contraction position at a desired speed.

[0007]

In order to solve the above-mentioned problems, a structure adopted by the invention of claim 1 is a cylinder having one end open to the atmosphere and the other end provided with a rod guide, It is slidably inserted in the cylinder in the axial direction,
A piston that is defined by an atmosphere chamber that is located in one side inside the cylinder and is open to the atmosphere and a gas chamber that is located in the other side and is filled with pressurized gas; one end side is fixed to the piston and the other end side is A piston rod protruding outside the cylinder through the rod guide, a check valve provided at one end side of the cylinder and allowing only the inflow of the atmosphere into the atmosphere chamber, and an atmosphere chamber provided at the one end side of the cylinder And an orifice that imparts flow resistance to the atmosphere flowing out from.

The configuration adopted by the invention of claim 2 is as follows.
A cylinder having one end open to the atmosphere and a rod guide provided at the other end is slidably inserted into the cylinder in the axial direction, and the inside of the cylinder is located on one side of the atmosphere chamber and on the other side. And a piston chamber defined by a gas chamber filled with pressurized gas, one end side of which is fixed to the piston and the other end side of which extends outside the cylinder via the rod guide, and a piston chamber inside the cylinder. The gas chamber is defined by two chambers, that is, a constant volume chamber having a constant volume and a variable chamber whose volume increases and decreases in accordance with the contraction and extension of the piston rod. A check valve that allows only the flow of gas from the variable chamber to the fixed amount chamber, and an orifice that is provided in the partition member and that imparts flow resistance to the gas that flows into the variable chamber from the fixed amount chamber.

[0009]

According to the structure of the first aspect of the invention, when the piston rod is extended by applying an external force, the piston moves to the other side in the cylinder to pressurize the gas chamber, while the atmospheric chamber becomes negative pressure. Inhale air through check valve. When the external force on the piston rod is reduced in this state, the piston rod is reduced by the gas pressure in the gas chamber against the external force. At this time, since the amount of the air in the air chamber is regulated by the orifice, the pressure in the air chamber is increased and acts as a resistance force on the piston rod moving in the contracting direction. As a result, the piston rod gradually contracts from the pressurized atmosphere chamber through the orifice so that the atmosphere gradually flows into the atmosphere.

According to the second aspect of the present invention, when the piston rod is extended by applying an external force, the piston moves to the other side in the cylinder to pressurize the gas chamber and is defined by the defining member. The volume of the variable chamber is reduced, and the pressurized gas in the variable chamber flows into the metering chamber through the check valve. Then, when the external force on the piston rod is reduced in this state, the piston rod is reduced by the gas pressure in the variable chamber of the gas chamber against the external force. At this time, although the gas pressure in the variable chamber is reduced as the piston rod shrinks, the pressurized gas gradually flows into the variable chamber from the metering chamber through the orifice, so that the piston rod moves to the metering chamber. The pressure of the pressurized gas gradually flowing from the chamber gradually reduces.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gas spring according to an embodiment of the present invention will be described below with reference to FIGS.

First, FIGS. 1 and 2 show a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a cylinder which constitutes a gas spring main body. The cylinder 1 is formed of a long tube, the lower end side is closed by a bottom cap 1A, and the rod guide 2 is fixedly attached at the upper end side. There is. An annular stopper portion 1B located below the rod guide 2 by a predetermined distance from the rod guide 2 and restricting an upward movement amount of a piston 4 to be described later is formed by caulking, and is provided above the bottom cap 1A. The fixed convex portions 1C and 1D for fixing the valve mechanism 9 described later are formed by caulking. Further, a mounting bracket 3 is fixed to the cylinder 1 by welding on the lower surface side of the bottom cap 1A, and the bottom cap 1A and the fixed convex portion 1D.
A ventilation hole 1E in the radial direction is formed between the and.

Reference numeral 4 denotes a piston slidably inserted in the cylinder 1. The piston 4 defines the inside of the cylinder 1 into a lower atmosphere chamber A and an upper gas chamber B. .
An O-ring 5 for airtightly sealing with the cylinder 1 is mounted on the outer peripheral side of the piston 4, and an O-ring 6 for airtightly sealing with a piston rod 7 described later is mounted on the inner peripheral side. It is installed. Here, the atmosphere flows into the atmosphere chamber A through the vent holes 1E, and the gas chamber B is filled with pressurized gas by the O-rings 5 and 6.

Reference numeral 7 denotes a piston rod having a lower end fixed to the piston 4 and an upper end protruding to the outside of the cylinder 1 through the rod guide 2, and a mounting bracket 8 is attached to the protruding end of the piston rod 7 by means such as welding. It is stuck in.

Numeral 9 is located in the cylinder 1 and is a fixed convex portion 1
A valve mechanism 10 as a check valve, which is fixed between C and 1D and has an atmosphere opening space C communicating with the atmosphere via a ventilation hole 1E below the atmosphere chamber A, includes a disk valve 11 and a fixed shaft 12 which will be described later. A valve main body that constitutes the valve mechanism 9 is also shown, and an insertion hole 1 into which a fixed shaft 12 is inserted, as shown in FIG.
0A is provided so as to penetrate in the axial direction. Further, the valve body 10 is formed with an annular groove 10B located on the upper surface side so as to open to the atmosphere chamber A, and the annular groove 10B communicates with the atmosphere open space C through the communication holes 10C, 10C. is doing.

Reference numeral 11 denotes a disc valve disposed on the upper surface side of the valve body 10, and 12 denotes a fixed shaft inserted into the insertion hole 10A for fixing the disc valve 11 to the valve body 10. The disc valve 11 is separated from the upper surface of the valve body 10 when the atmosphere flows from the atmosphere open space C to the atmosphere chamber A to allow this, and the opposite flow is seated on the upper surface of the valve body 10 to be regulated. To do.

Reference numeral 13 designates an orifice located on the upper surface side of the valve body 10 and radially outwardly cut out from the annular groove 10B, and the orifice 13 is predetermined in the atmosphere flowing from the atmosphere chamber A to the atmosphere open space C. It gives the flow resistance of.

Reference numeral 14 designates a seal member which is located on the lower surface side of the rod guide 2 and is fixed in the cylinder 1. The seal member 14 allows the piston rod 7 to slide and at the same time pressurizes gas in the gas chamber B. Is to prevent the leakage of the outside.

The gas spring according to the present embodiment has the above-mentioned structure, and its operation will be described below by taking the case where the gas spring is used as a door opening / closing device as an example.

First, for example, the mounting bracket 3 of the cylinder 1 is rotatably pin-connected to the frame (not shown) side of the door, and the mounting bracket 8 of the piston rod 7 is pin-connected to the door side.

In this state, when the door is opened by an external force and the piston rod 7 is extended, the piston 4 fixed to the piston rod 7 moves to the rod guide 2 side in the cylinder 1, and the gas chamber B becomes The volume is reduced and the pressure is increased, and the atmosphere chamber A is expanded to a negative pressure. Therefore, the atmosphere flowing into the atmosphere chamber A through the ventilation hole 1E causes the disk valve 11 to separate from the atmosphere opening space C, and flows into the atmosphere chamber A through the communication holes 10C of the valve body 10 with almost no resistance. To do.

When the external force applied to the door is removed in this state, the piston rod 7 is contracted by the piston 4 that has received the gas pressure of the pressurized gas pressurized in the gas chamber B. At this time, the piston 4 moves to the bottom cap 1A side to reduce the volume of the atmosphere chamber A, but since the amount of the atmosphere in the atmosphere chamber A flowing out to the atmosphere open space C is regulated by the orifice 13, The atmosphere in the atmosphere chamber A is pressurized and acts as a resistance force on the piston 4 moving to the bottom cap 1A side.

As a result, the piston rod 7 is given a resistance to movement in the contracting direction by the atmosphere pressurized in the atmosphere chamber A via the piston 4, and the piston rod 7 is moved.
From the orifice 13 to the annular groove 10B and each communication hole 10C
The atmosphere gradually flows out to the atmosphere open space C via and the inside of the atmosphere chamber A is decompressed, so that the movement to the bottom cap 1A side is allowed. As a result, the piston rod 7
Although the inside of the cylinder 1 is gradually moved to the bottom cap 1A side along with the piston 4 in accordance with the decompression of the atmosphere chamber A, it acts on the piston 4 until the inside of the atmosphere chamber A is pressurized to some extent by the piston 4 in the initial stage of contraction. Since the resistance force is small, the piston rod 7 contracts with a large reduction force, and thereafter, the resistance force by the atmosphere in the atmosphere chamber A acts on the piston 4 almost constantly, and the piston rod 7 contracts with a relatively small reduction force. The door is gradually closed via the piston rod 7.

Thus, according to the present embodiment, when the piston rod 7 is extended, the disc valve 11 is opened and the atmosphere is introduced into the atmosphere chamber A through the communication holes 10C of the valve body 10 without any resistance, and the piston is When the rod 7 shrinks, the piston rod 7 is resisted by the atmosphere pressurized in the atmosphere chamber A, while the orifice 13 provides flow resistance to the atmosphere flowing out into the atmosphere to gradually reduce the pressure in the atmosphere chamber A. Because it is configured to
The piston rod 7 can be easily extended, and when the piston rod 7 is contracted, it can be contracted at a slow speed from the maximum expansion position to the minimum contraction position by the orifice.

Here, for example, when the gas spring is used for automatically closing the door, the door can be opened with a light force, and when the door is closed, the door is closed at a desired and constant closing speed over the entire area. Can be made. In particular,
Since the door requires a large force at the time of closing the door, the door can be closed from a stopped state by a large contracting force until the atmospheric chamber A is pressurized to some extent by the piston 4, and thereafter the atmospheric chamber A is closed. Due to the resistance of the atmosphere, the door can be gradually closed with a small reduction force.

Next, FIGS. 3 and 4 show a second embodiment of the present invention. The feature of this embodiment is that a valve mechanism having an orifice is provided in the gas chamber to prevent flow resistance when the pressurized gas flows. This is because the reduction speed of the piston rod is made almost constant by giving it. In this embodiment, the same components as those in the first embodiment shown in FIG. 1 described above are designated by the same reference numerals and the description thereof will be omitted.

In the figure, reference numeral 21 denotes a cylinder according to this embodiment which constitutes a gas spring main body, and the cylinder 2
1 is formed of a long tube, the lower end side is closed by a bottom cap 21A, and the rod guide 2 is fixed to the upper end side. An annular stopper portion 21B located below the rod guide 2 by a predetermined dimension and an annular stopper portion 21C located above the bottom cap 21A by a predetermined dimension are formed on the cylinder 1 by caulking. The stopper portions 21B and 21C regulate the upward and downward movement amounts of a piston 22 and a valve mechanism 24, which will be described later. Further, the mounting bracket 3 is fixed to the cylinder 21 by welding on the lower surface side of the bottom cap 21A, and a ventilation hole 21D is formed in the radial direction between the bottom cap 21A and the stopper portion 21C.

Reference numeral 22 denotes a piston slidably fitted in the cylinder 21, and the piston 22 is the lower atmospheric chamber inside the cylinder 21 like the piston 4 described in the first embodiment. It is defined by D and the upper gas chamber E. Here, the atmosphere chamber D is opened to the atmosphere through the vent hole 21D, and the gas chamber E is filled with a pressurized gas.

The lower end of the cylinder 23 has a small diameter portion 2 inside the cylinder 21.
3A, the upper end side shows a piston rod protruding outside the cylinder 21 via the rod guide 2, and a mounting bracket 8 is fixed to the protruding end side of the piston rod 23 by means such as welding. In addition, the piston 22 has a valve mechanism 2 on the lower end side of the small diameter portion 23A of the piston rod 23.
It is fixed together with 4 etc.

Reference numeral 24 denotes a valve mechanism as a check valve which is positioned in the gas chamber E in the cylinder 21 and is slidably inserted in the axial direction and fixed to the upper end of the small diameter portion 23A of the piston rod 23. The valve mechanism 24 is located at the upper side of the gas chamber E and has a variable chamber F whose volume is increased or decreased in accordance with the contraction and extension of the piston rod 23 (movement of the valve mechanism 24) and the fixed volume at the lower side. It is defined as a room G.

Reference numeral 25 denotes a valve body as a defining member which constitutes a valve mechanism 24 together with a disc valve 27 which will be described later. At the center of the valve body 25, as shown in FIG. An insertion hole 25A through which 23A is inserted is formed so as to penetrate in the axial direction. In addition, the valve main body 25 is located on the lower surface side and is located in the metering chamber
An annular groove 25B is formed so as to open at
5B communicates with the variable chamber F through the communication holes 25C, 25C. Further, an O-ring 26 is mounted on the outer peripheral side of the valve body 25 so as to hermetically seal the valve body 25 and the cylinder 21.

Reference numeral 27 denotes a disc valve disposed on the lower surface side of the valve body 25. The disc valve 27 is separated from the lower surface of the valve body 25 when the pressurized gas flows from the variable chamber F to the metering chamber G. The seat is seated to allow this, and the opposite flow is seated on the lower surface of the valve body 25 to be restricted.

Reference numeral 28 denotes an orifice located on the lower surface side of the valve main body 25 and radially outwardly cut out from the annular groove 25B, and the orifice 28 is provided for the pressurized gas flowing from the fixed amount chamber G to the variable chamber F. It provides a predetermined flow resistance.

29 is a small diameter portion 23A of the piston rod 23.
A cylindrical member provided on the outer periphery between the piston 22 and the valve mechanism 24 is shown. The cylindrical member 29 separates the piston 22 and the valve mechanism 24 from each other by a predetermined distance, and The disc valve 27 is fixed to the lower surface side.

The gas spring according to this embodiment has the above-mentioned structure, and its operation will be described below.

First, when the piston rod 23 is extended by an external force, the piston 22 and the valve mechanism 24 fixed to the piston rod 23 move to the rod guide 2 side in the cylinder 21. As a result, the volume of the gas chamber E is reduced by the movement of the piston 22 to increase the pressure, and the volume of the variable chamber F is reduced by the movement of the valve mechanism 24 to increase the pressure. The pressurized gas in the chamber F flows into the metering chamber G without resistance while the disc valve 27 is separated. On the other hand, the atmosphere chamber D has the piston 2
By the movement of 2, the pressure is expanded to a negative pressure, and the atmosphere flows into the atmosphere chamber D through the ventilation hole 21D.

When the external force on the piston rod 23 is removed, the piston rod 23 is contracted by the valve body 25 of the valve mechanism 24 which receives the pressure of the pressurized gas in the variable chamber F of the gas chamber E. At this time, although the variable chamber F is decompressed as the valve mechanism 24 moves, in the depressurized variable chamber F, the fixed chamber G to the orifice 2
8, the pressurized gas gradually flows in a fixed amount through the annular groove 25B and the communication holes 25C. As a result, the piston rod 23 contracts inside the cylinder 21 together with the piston 22 at a substantially constant speed by the pressure in the variable chamber F, which is pressurized by the pressurized gas flowing from the fixed amount chamber G. At this time, the atmosphere in the atmosphere chamber D is released into the atmosphere via the ventilation hole 21D.

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effects as those of the first embodiment, but particularly in this embodiment, the piston 22 and the valve 22 are provided on the piston rod 23. Since the mechanism 24 is attached, the piston 22 and the valve mechanism 24 can be assembled by simply inserting the piston 22 and the valve mechanism 24 into the cylinder 21 with the piston rod 23 attached, and the assembling work can be facilitated.

Next, FIGS. 5 and 6 show a third embodiment of the present invention, in which the same components as those in the first embodiment shown in FIG. Will be attached and the description thereof will be omitted.

In the figure, reference numeral 31 denotes a cylinder which constitutes a gas spring main body. The cylinder 31 is formed by a long tube, the lower end side is closed by a bottom cap 31A, and the rod guide 2 is fixedly attached at the upper end side. There is. An annular stopper portion 31B, which is located above the bottom cap 31A by a predetermined size and regulates the amount of downward movement of the piston 4, is located at an axially intermediate portion of the cylinder 31 and is described later. Fixed convex portions 31C for fixing 33 are formed by caulking. A mounting bracket 3 is fixed to the cylinder 31 by welding on the lower surface side of the bottom cap 31A, and a ventilation hole 31D is formed in the radial direction between the bottom cap 31A and the stopper portion 31B.

Reference numeral 32 denotes a piston slidably fitted in the cylinder 31, and the piston 32 is located inside the cylinder 31 in the lower atmosphere chamber, like the piston 4 described in the first embodiment. H and the upper gas chamber J are defined. Here, the atmosphere chamber H is opened to the atmosphere through the vent hole 31D, and the gas chamber J is filled with a pressurized gas.

Reference numeral 33 denotes a valve mechanism as a check valve which is located in the gas chamber J in the cylinder 31 and is fixed in the cylinder 31 via a fixed convex portion 31C. The valve mechanism 33 is the gas chamber J. Is defined on the upper side as a fixed volume chamber K having a constant volume and on the lower side as a variable chamber L whose volume is increased or decreased in accordance with the contraction and extension of the piston rod 7 (movement of the piston 32).

Reference numeral 34 denotes a valve body as a defining member which constitutes a valve mechanism 33 together with a disc valve 36 and a fixing member 37 which will be described later, and a piston rod is provided at the center of the valve body 34 as shown in FIG. A through hole 34 </ b> A in which 7 is movably inserted in the axial direction is formed by penetrating in the axial direction. Further, an annular groove 34B is formed on the valve body 34 so as to be located on the upper surface side and open to the metering chamber K, and the annular groove 34B communicates with the variable chamber L via communication holes 34C, 34C. ing. Further, the through hole 34A
An O-ring 35 that hermetically seals the piston rod 7 is attached to the. Also, the valve body 3
A fitting groove 34D into which the fitting portion 37B of the fixing member 37 is fitted is provided on the outer peripheral side of the groove 4 in the circumferential direction.

Reference numeral 36 denotes a disc valve disposed on the upper surface side of the valve body 34. The disc valve 36 is separated from the upper surface of the valve body 34 when the pressurized gas flows from the variable chamber L to the metering chamber K. The seat is seated to allow this, and the opposite flow is seated on the upper surface of the valve body 34 to be restricted.

Reference numeral 37 denotes a cylindrical fixing member provided on the outer peripheral side of the valve body 34, and the outer peripheral side of the disc valve 36 is provided on the upper end side of the fixing member 37.
A fixing portion 37A that is fixed to the inside is provided so as to project radially inward. Then, the fixing member 37 is fitted with the fitting portion 34B formed on the lower end side by the fixing convex portion 31C of the cylinder 31 in the fitting groove 34D of the valve body 34, so that the fixing member 37 and the cylinder 31 together with the valve body 34. It is fixed to.

Reference numeral 38 denotes an orifice located on the upper surface side of the valve body 34 and notched inward in the radial direction from the annular groove 34B. The orifice 38 serves as a pressurized gas flowing from the metering chamber K to the variable chamber L. It provides a predetermined flow resistance.

The gas spring according to this embodiment has the above-mentioned structure, and its operation will be described below.

First, when the piston rod 7 is extended by an external force, the piston 32 fixed to the piston rod 7 moves in the cylinder 31 toward the rod guide 2 side.
As a result, the volume of the gas chamber J is reduced by the movement of the piston 32 and the pressure is increased, and the volume of the variable chamber L is reduced and the pressure is increased as the piston 32 approaches the valve mechanism 33. As a result, the pressurized gas in the variable chamber L flows into the metering chamber K without resistance while the disc valve 36 is separated. On the other hand, the atmosphere chamber H is expanded by the movement of the piston 32 to a negative pressure, and the ventilation hole 3
Atmosphere flows in through 1D.

When the external force applied to the piston rod 7 is removed, the piston rod 7 is contracted by the piston 32 that has received the pressure of the pressurized gas boosted in the variable chamber L of the gas chamber J. At this time, the variable chamber L is decompressed with the movement of the piston 32. However, in the decompressed variable chamber L, the fixed chamber K, the orifice 38, and the valve body 3 are discharged.
A fixed amount of the pressurized gas gradually flows in through the four annular grooves 34B and the communication holes 34C. As a result, the piston rod 7 moves inside the cylinder 31 by the pressure of the variable chamber L, which is boosted by the pressurized gas flowing from the fixed amount chamber K.
It shrinks with 2 at an almost constant speed. At this time, the atmosphere in the atmosphere chamber H is released into the atmosphere via the ventilation hole 31D.

Thus, also in the present embodiment having such a configuration, it is possible to obtain substantially the same operational effects as those of the above-mentioned respective embodiments.

Although the atmosphere opening space C is defined below the atmosphere chamber A by the valve mechanism 9 in the first embodiment, the valve body having the orifice in the vent hole 1E of the cylinder 1 is directly connected to the air chamber. It may be separated and seated. In this case, the axial dimension of the cylinder can be shortened by the amount of the atmosphere opening space C, and the gas spring can be downsized.

In the first embodiment, the case where the orifice 13 is incorporated in a part of the valve mechanism 9 has been described as an example, but the present invention is not limited to this, and the valve mechanism may be used as a check valve, for example. Only the function may be performed, and the orifice may be bored in the radial direction of the cylinder 1 so that the atmosphere chamber A can communicate with the atmosphere.

[0054]

As described above in detail, according to the first aspect of the invention, the inside of the cylinder is defined by the piston in the atmosphere chamber open to the atmosphere and the gas chamber located on the piston rod side and containing the pressurized gas. Since the check valve allows only the inflow of the atmosphere into the atmosphere chamber and the orifice provides a flow resistance to the atmosphere flowing out of the atmosphere chamber, a negative pressure is applied when the piston rod is extended by applying an external force. The atmosphere can be sucked into the atmosphere chamber through a check valve without resistance, and when the external force on the piston rod is reduced, the piston rod is reduced by the gas pressure in the gas chamber against the external force. At this time, a piston rod that pressurizes the atmosphere chamber to move the atmosphere in a contracting direction by regulating the outflow amount of the atmosphere in the atmosphere chamber by an orifice Together to act as a resistance force,
The piston rod can be gradually moved in the contraction direction by gradually decompressing the atmosphere chamber by the atmosphere discharged through the orifice, and the piston rod is contracted from the maximum extension position to the minimum contraction position at a desired speed. Can be made.

According to the second aspect of the invention, the inside of the cylinder is defined by the piston into an atmosphere chamber open to the atmosphere and a gas chamber which is located on the piston rod side and is filled with pressurized gas. A member defines the gas chamber into two chambers, a constant volume chamber having a constant volume and a variable chamber whose volume increases and decreases according to the contraction and extension of the piston rod. Since a check valve that allows only the flow of gas and an orifice that gives flow resistance to the gas flowing from the fixed amount chamber to the variable chamber is provided, the volume decreases when the piston rod is extended by applying an external force. When the pressurized gas in the variable chamber is flown into the metering chamber through the check valve without resistance and the external force on the piston rod is reduced, the piston rod is reduced by the gas pressure in the variable chamber against the external force. At this time, a constant amount of pressurized gas is gradually flowed from the metering chamber through the orifice into the variable chamber that is decompressed as the piston rod moves. The gas can gradually move the piston rod in the contraction direction, and can contract the piston rod from the maximum extension position to the maximum contraction position at a desired speed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a gas spring according to a first embodiment of the present invention.

FIG. 2 is an enlarged vertical cross-sectional view of essential parts showing a valve mechanism, an orifice and the like in FIG.

FIG. 3 is a vertical sectional view showing a gas spring according to a second embodiment.

FIG. 4 is an enlarged vertical sectional view of an essential part showing a valve mechanism, an orifice and the like in FIG.

FIG. 5 is a vertical sectional view showing a gas spring according to a third embodiment.

FIG. 6 is an enlarged vertical sectional view of an essential part showing a valve mechanism, an orifice and the like in FIG.

[Explanation of symbols]

 1, 21, 31 Cylinder 1E, 21D, 31D Vent hole 2 Rod guide 4, 22, 32 Piston 7, 23 Piston rod 9, 24, 33 Valve mechanism (check valve) 13, 28, 38 Orifice 25, 34 Valve body ( Definition member) A, D, H Atmosphere chamber B, E, J Gas chamber F, L Variable chamber G, K Fixed amount chamber

Claims (2)

[Claims] 1. A cylinder having one end open to the atmosphere and a rod guide provided on the other end, and a cylinder slidably inserted in the cylinder so as to be positioned inside the cylinder on one side. A piston defined by an atmosphere chamber open to the atmosphere and a gas chamber located on the other side and filled with pressurized gas, one end of which is fixed to the piston and the other end of which protrudes out of the cylinder through the rod guide. Piston rod, a check valve provided at one end side of the cylinder for allowing only the air to flow into the atmosphere chamber, and an orifice provided at the one end side of the cylinder for giving flow resistance to the atmosphere flowing out of the atmosphere chamber. A gas spring composed of and. 2. A cylinder having one end open to the atmosphere and a rod guide provided at the other end, and a cylinder slidably inserted in the cylinder in the axial direction to form an atmosphere chamber on one side in the cylinder. A piston that is located on the other side and is defined by a gas chamber that is filled with pressurized gas; a piston rod that has one end fixed to the piston and the other end that protrudes outside the cylinder via the rod guide; Provided in the gas chamber of the cylinder,
A defining member in which the gas chamber is defined into two chambers, that is, a constant volume chamber having a constant volume and a variable chamber whose volume increases and decreases according to the contraction and extension of the piston rod, and the variable member is provided in the defining member. A gas spring comprising a check valve which allows only the flow of gas from the fixed quantity chamber to the fixed quantity chamber, and an orifice which is provided in the partition member and gives a flow resistance to the gas flowing from the fixed quantity chamber into the variable chamber.