JPH1163062A - Gas spring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate a piston rod without operating an operation pin and improve the operability during handling. SOLUTION: The valve head 12 of a valve disc 10 is largely expanded from a valve stem 11 and the pressure receiving area of a conical pressure receiver 12B to receive pressure in an annular oil chamber E is formed to be sufficiently large by the annular oil chamber E formed with an expanded oil passage 9. When a piston rod 8 is elongated in addition to the normal opening/closing operation of the valve disc 10 by using an operation pin 18, the piston rod 8 is pulled to increase pressure in the annular oil chamber E. In this way, the valve disc 10 can be opened and the operation of the operation pint 18 can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas spring device suitable for use in, for example, a back angle adjusting mechanism and a height adjusting mechanism mounted on a bed or a chair.

[0002]

2. Description of the Related Art In general, there are beds, chairs and the like in which the angle, height, etc. of each part can be adjusted according to the physique and posture of a user. For example, the upper body is raised from a sleeping state. In the case of a reclining bed that can be adjusted, it has a back angle adjustment mechanism that adjusts the angle of the part corresponding to the backrest, and in the case of a lifting chair, a height adjustment mechanism that adjusts the height of the seat It has. A gas spring device is used as a component of these adjustment mechanisms, and this type of gas spring device is known, for example, from Japanese Patent Application Laid-Open No. 2-46334.

[0003] Here, the gas spring device according to the prior art is a cylinder in which oil and gas are sealed, and is slidably inserted into the cylinder to define an oil chamber and a gas chamber inside the cylinder. A component member, a piston slidably inserted into the oil chamber and defining the oil chamber as two chambers, a gas chamber side oil chamber and a piston rod side oil chamber, and one end connected to the piston and the other end connected to the piston. A hollow piston rod extending outside the cylinder, an oil passage formed in the axial direction of the piston and communicating the gas chamber side oil chamber and the piston rod side oil chamber, and a valve shaft extending in the axial direction of the oil passage. A valve body that is provided so as to be displaceable, communicates and shuts off between the gas chamber side oil chamber and the piston rod side oil chamber by a valve head being separated from and seated on the piston,
And an operation pin provided in a hollow portion of the piston rod to operate the valve body.

As a result, the valve body is normally seated on the piston by the pressure of the gas chamber side oil chamber, and the valve body blocks the gas chamber side oil chamber and the piston rod side oil chamber. Is fixed to the piston rod.

Further, when the operating pin is operated from the outside by using a lever or the like and the valve body is separated from the piston, the shutoff between the oil chambers by the valve body is released, and the gas chamber side via the oil passage is released. The oil chamber communicates with the piston rod-side oil chamber. This allows the oil liquid to flow between the oil chambers, so that the piston rod can be extended or contracted by moving the piston rod in the axial direction with respect to the cylinder, and the amount of extension with respect to the cylinder can be reduced. Can be adjusted.

[0006]

In the gas spring device according to the prior art described above, when the piston rod is extended or contracted with respect to the cylinder, the operation pin does not need to be pushed via a lever or the like. Therefore, there is a problem in that the adjustment work requires time and effort and the handling becomes troublesome.

The present invention has been made in view of the above-mentioned problems of the prior art. An object of the present invention is to extend a piston rod without operating an operation pin, and to move a valve body by the operation of extending the piston rod. An object of the present invention is to provide a gas spring device capable of opening and closing an oil passage, thereby improving operability during handling.

[0008]

A gas spring device according to the present invention comprises: a cylinder in which oil and gas are sealed;
A defining member slidably inserted in the cylinder and defining the interior of the cylinder as an oil chamber and a gas chamber, and an oil chamber slidably inserted in the oil chamber and defining the oil chamber as a gas chamber-side oil chamber. A piston defining two piston rod-side oil chambers, a hollow piston rod having one end connected to the piston and the other end extending outside the cylinder, and a gas chamber side formed in an axial direction of the piston. An oil passage communicating between the oil chamber and the piston rod-side oil chamber; and a valve shaft provided so as to be displaceable in an axial direction of the oil passage. The valve body includes a valve body that communicates with and shuts off the piston rod-side oil chamber, and an operation pin that is provided in a hollow portion of the piston rod and operates the valve body.

Then, in order to solve the above-mentioned problem,
The invention according to claim 1 is characterized in that the piston is provided with an annular oil chamber surrounding the outer periphery of the valve shaft of the valve element by forming the oil passage so as to have a larger diameter. The head has a pressure receiving portion for receiving the pressure guided to the annular oil chamber.

With this configuration, when the operating pin is operated to separate the valve body from the piston, the oil chamber on the gas chamber side and the oil chamber on the piston rod side communicate with each other via the oil passage. Thereby, the oil liquid can be circulated between the gas chamber side oil chamber and the piston rod side oil chamber, so that by moving the piston rod in the axial direction with respect to the cylinder, the extension amount of the piston rod can be reduced. Can be adjusted. Also, when the push of the valve body by the operation pin is stopped,
Since the valve head of the valve body is pressed against the piston by the pressure of the gas chamber side oil chamber, the valve body shuts off the gas chamber side oil chamber and the piston rod side oil chamber. Fixed.

On the other hand, when the piston rod is forcibly pulled (a force is applied in a direction in which the piston rod is extended), the pressure in the piston rod-side oil chamber increases, and the pressure is increased by the annular oil formed by expanding the oil passage. Guided to the room. Since the pressure guided to the annular oil chamber is received by the annular oil chamber by the pressure receiving portion of the valve element having a large pressure receiving area, a force acts on the valve element in a direction away from the piston by this pressure. .
Therefore, the force acting in the direction of raising the pressure of the annular oil chamber and separating the valve body from the piston is made larger than the force acting in the direction of seating the valve body on the piston by the pressure of the gas chamber side oil chamber. Thus, the valve body can be separated from the piston, and the gas chamber side oil chamber and the piston rod side oil chamber can be communicated via the oil passage. Thereby, the piston rod can be extended from the cylinder by continuously pulling the piston rod.

When the force for pulling the piston rod is reduced or stopped, the force for seating the valve body on the piston by the pressure in the gas chamber side oil chamber is the force for separating the valve body from the piston by the pressure in the annular oil chamber. Therefore, the valve element blocks the gas chamber side oil chamber and the piston rod side oil chamber, and the piston rod is fixed at that position.

According to a second aspect of the present invention, an O-ring is provided on the outer periphery of the valve shaft of the valve body to maintain a liquid-tight space between the outer periphery of the valve shaft and the inner periphery of the hollow portion of the piston rod. A washer is provided for receiving the pressure guided to the annular oil chamber and preventing the O-ring from receiving this pressure.

[0014] With this configuration, since the pressure guided to the annular oil chamber is received by the washer, it is possible to prevent the O-ring from being deformed by this pressure. For this reason, it is possible to prevent a delay in opening the valve body, a poor opening of the valve, and the like due to the pressure being used to deform the O-ring.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gas spring device according to an embodiment of the present invention will be described in detail with reference to FIGS.

Reference numeral 1 denotes a gas spring device according to the present embodiment. The gas spring device 1 includes a cylinder 2, a free piston 6, a piston 7, a piston rod 8, an oil passage 9, a valve body 10, a washer 17, and an operation pin 18 which will be described later. And so on.

Reference numeral 2 denotes a cylindrical cylinder which forms an outer shell of the gas spring device 1, and the upper end of the cylinder 2 is gas-liquid closed by a cap 2A. The cap 2A is provided with one cylinder (not shown).
An attachment eye 3 for attachment to the camera is fixed.

Reference numeral 4 denotes a rod guide that is caulked and fixed to the lower end of the cylinder 2. The rod guide 4 slidably supports the piston rod 8, and a seal member 5 is provided above the rod guide.

Reference numeral 6 denotes a free piston, which is located near the upper side of the cylinder 2 and serves as a defining member slidably inserted into the cylinder 2, and the free piston 6 has a gas chamber between the free piston 6 and the cap 2A. A is defined, and a pressurized gas is sealed in the gas chamber A. An oil liquid is sealed below the free piston 6 between the free piston 6 and the seal member 5.

Reference numeral 7 denotes a piston provided in the cylinder 2. The piston 7 includes, as shown in FIG. 2, a partition 7A slidably inserted in the cylinder 2 in the axial direction, and a partition 7A. The partition wall portion 7A is substantially constituted by a shaft portion 7B extending downward from the center of 7A, and the partition wall portion 7A is provided with an upper oil chamber B serving as a gas chamber side oil chamber between the free piston 6 and the seal member 5 in the cylinder 2. And a lower oil chamber C which is a piston rod side oil chamber between the two. In the center of the shaft portion 7B, a small-diameter hole 7 extending in the axial direction over the partition wall portion 7A is provided.
C and a large-diameter hole 7D extending in the axial direction by enlarging the lower end of the small-diameter hole 7C, and a valve seat receiving step in which a valve seat portion 13 is fitted on the upper end side of the small-diameter hole 7C. A portion 7E is formed.

Reference numeral 8 denotes one end of the rod 2 which is fixed by caulking in the large-diameter hole 7D of the piston 7 in the cylinder 2 and the other end of the rod guide 4
With a piston rod extending out of the cylinder 2 through
The piston rod 8 is formed as a hollow shaft having a center as a pin insertion hole 8A, and a large diameter accommodation portion 8B for accommodating a valve shaft guide 15 and an O-ring 16 described later is formed at one end of the pin insertion hole 8A. Have been. On the other end side of the piston rod 8, a screw portion 8C for attaching the piston rod 8 to the other fixing portion (not shown) is formed.

Reference numeral 9 denotes oil passages formed in the axial direction of the piston 7. Each of the oil passages 9 includes a small diameter hole 7C of the piston 7, and one end of the oil passage 9 is provided with lower oil chambers through oil holes 9A, 9A. C
, And the other end thereof communicates with the upper oil chamber B via the valve seat 13. In the oil passage 9, an annular oil chamber E surrounding the outer periphery of the valve shaft 11 is defined by expanding the diameter of the oil passage 9 from the valve shaft 11.

Reference numeral 10 denotes a valve element provided on the piston 7. The valve element 10 has a rod-shaped valve shaft 11 provided to be displaceable in the axial direction of the oil passage 9, and an upper end side of the valve shaft 11. A flat pressure-receiving portion 1 having an upper end surface for receiving a pressure P1 of the upper oil chamber B.
2A, the lower end side of which receives the pressure P2 of the annular oil chamber E (the pressure P2 of the lower oil chamber C), and the outer peripheral side thereof is a conical pressure receiving portion 12B which is detachably seated on the valve seat portion 13.

Here, in the valve element 10, the outer diameter D2 of the valve head 12 is formed sufficiently larger than the outer diameter D1 of the valve shaft 11, whereby the pressure P2 of the annular oil chamber E is reduced. The head 12 can be reliably received.

Reference numeral 13 denotes a valve seat portion fixed to the valve seat accommodating step portion 7E of the piston 7 via a thin plate 14.
Reference numeral 3 denotes an annular ring made of a highly elastic material such as urethane resin, for example, and a conical valve seating surface 13 on the inner peripheral side of which a conical pressure receiving portion 12B formed on a valve head 12 of the valve body 10 is detachably seated.
A is formed. Further, the valve seat 13 is provided with an annular oil chamber E.
Is formed with a sufficiently large inner diameter d1 so that the conical pressure receiving portion 12B of the valve head 12 can have a large pressure receiving area, and the pressure P2 of the annular oil chamber E can be increased. It can work efficiently.

Reference numeral 15 denotes a large-diameter accommodation portion 8B for the piston rod 8.
A cylindrical valve shaft guide fitted into the valve shaft guide 1
5 guides the valve shaft 11 of the valve body 10 slidably in the axial direction.

Reference numeral 16 denotes an O-ring slidably contacting the outer periphery of the valve shaft 11 and disposed above the valve shaft guide 15 in the enlarged diameter accommodating portion 8B of the piston rod 8; And a liquid-tight space between the piston rod 8 and the enlarged diameter accommodation portion 8B at the tip of the piston rod 8.

Reference numeral 17 denotes a small diameter hole 7C and a large diameter hole 7 of the piston 7.
A washer sandwiched between the stepped portion between D and the tip of the piston rod 8, and the washer 17 is made of a non-deformable material, and its inner peripheral surface slides almost fluid-tightly on the valve shaft 11 of the valve body 10. In contact. The washer 17 prevents the O-ring 16 from being deformed by receiving the pressure P2 of the annular oil chamber E, thereby applying the pressure P2 of the annular oil chamber E to the conical pressure receiving portion 12B of the valve head 12. It works. Further, by preventing deformation of the O-ring 16, the sliding resistance to the valve element 10 is kept constant, and the valve element 10 also has a function of operating satisfactorily.

Reference numeral 18 denotes a pin insertion hole 8A of the piston rod 8.
The operation pin 18 has an upper end contacting the valve shaft 11 of the valve body 10 and a lower end protruding from the piston rod 8. The protruding end of the operation pin 18 is in contact with an operation lever (not shown) for operating the valve body 10 via the operation pin 18.

The present embodiment is configured as described above. Next, the operation of the gas spring device 1 according to the present embodiment will be described.

First, the operation for adjusting the extension amount of the piston rod 8 by operating the operation pin 18 will be described.

In this case, the operation lever 18 is pushed by the operation lever in the direction of arrow a. Thereby, the valve element 10
Moves in the direction of arrow a, and the valve head 12 is separated from the conical valve seat surface 13A of the valve seat portion 13, so that the upper oil chamber B and the lower oil chamber C are connected via the oil passage 9. Communicate. Accordingly, the piston 7 is free to move in the axial direction with respect to the cylinder 2, and in this state, the piston rod 8 is pushed in the direction of the arrow a to push the piston rod 8 into the cylinder 2 and contract. Can be done. Further, the piston rod 8 can be extended from the cylinder 2 by pulling the piston rod 8 in the direction of the arrow b.

On the other hand, when the extension position of the piston rod 8 with respect to the cylinder 2 is determined, the pushing of the operation pin 18 by the operation lever is released. As a result, the valve element 10 moves in the direction of the arrow b due to the pressure P1 of the upper oil chamber B, and the valve element 1
Since the zero valve head 12 is seated on the valve seat 13, the space between the oil chambers B and C is shut off, and the piston rod 8 is fixed at that position.

Next, an operation method for extending the piston rod 8 without operating the operation pin 18 will be described.

In this case, the piston rod 8 is moved
In this direction, the piston 7 pressurizes the lower oil chamber C and guides the pressure to the annular oil chamber E.
Is increased, and this pressure P2 is applied to a conical pressure receiving portion 12B formed on the valve head 12 of the valve body 10.
Here, the force F _O acting in the direction to separate the valve body 10 from the valve seat portion 13 is determined as in the following Expression 1.

[0036]

## EQU1 ## where F _O = P 2 × A _O where A _{O is} the pressure receiving area of the conical pressure receiving portion 12B when the valve is closed.

The force F _C acting in the direction in which the valve body 10 is seated on the valve seat 13 is determined as in the following equation (2).

[0038]

## EQU2 ## where F _C = P 1 × A _C where P 1 is the pressure in the upper oil chamber B A _{C is} the pressure receiving area of the pressure receiving portion 12A

Accordingly, by increasing the pressure P2 in the annular oil chamber E so that F _O > F _C , the pressure P2 in the annular oil chamber E is increased.
The valve body 10 is moved in the direction indicated by the arrow a in FIG.
Can be separated from Thus, the piston rod 8 can be extended with respect to the cylinder 2 by continuing to pull the piston rod 8.

The pressure P2 led to the annular oil chamber E is
Since the pressure P2 is received by the washer 17 made of a non-deformable material, the pressure P2 can be directly applied to the valve head 12 of the valve body 10, and the valve opening operation of the valve body 10 can be performed smoothly. .

On the other hand, weaken or a force pulling the piston rod 8, when stopping, since the F _O ≦ F _C lowered the pressure P2 of the annular oil chamber E, receiving the pressure P1 in the upper oil chamber B The received valve body 10 sits on the valve seat portion 13 to shut off between the oil chambers B and C, and fixes the piston rod 8 at this position.

Thus, according to the present embodiment, the valve head 12 of the valve body 10 is greatly expanded from the valve shaft 11 and the oil head 9 is formed by the annular oil chamber E formed by expanding the oil passage 9.
The pressure receiving area A _O of the second conical pressure receiving portion 12B is formed large. Accordingly, when the piston rod 8 is extended in addition to the normal operation of opening and closing the valve body 10 using the operation pin 18, the piston rod 8 is pulled from the cylinder 2, so that the pressure P 2 of the annular oil chamber E is increased. Act on the conical pressure receiving portion 12B of the valve head 12 to open the valve body 10.

Therefore, in this embodiment, the piston rod 8 can be extended without operating the operation pin 18, so that the adjustment work can be simplified and the operability during handling can be improved.

When the pressure P2 in the annular oil chamber E is increased, the pressure P2 is received by the washer 17, thereby preventing the O-ring 16 from receiving the pressure P2 and being deformed. Since almost all of the pressure P2 of the oil chamber E can act on the conical pressure receiving portion 12B of the valve body 10, a delay in opening the valve body 10 due to the deformation of the O-ring 16, a poor opening of the valve body, and the like can be prevented. Thus, the valve element 10 can be opened smoothly and reliably.

The valve body 10 is connected to the upper oil chamber B and the annular oil chamber E.
The valve body 10 can be smoothly operated by the incompressible oil liquid since the valve body 10 is operated by the oil liquid filled in the valve body. The valve 10 and the valve seat 13 can be prevented from opening and closing the valve.
Etc., the life can be improved.

Further, since the lower surface of the valve head 12 is formed as a conical pressure receiving portion 12B, the pressure P2 of the annular oil chamber E can be efficiently received by the conical pressure receiving portion 12B. The pressure receiving portion 12B can be seated on the conical valve seat surface 13A of the valve seat portion 13 in a liquid-tight manner, and the oil chambers B and C can be reliably shut off when the valve is closed.

In the embodiment, the valve seat 13 is formed of a highly elastic material, and the washer 17 is formed of a non-deformable material. However, the present invention is not limited to this.
The valve seat 13 and the washer 17 are made of, for example, PTFE,
It may be formed from a highly elastic material having oil resistance and wear resistance such as PEEK and PET.

Further, in order to reduce the pulling force of the piston rod 8 when the valve body 10 is opened and to smoothly extend the piston rod 8, the inner diameter d1 of the valve seat 13 must be adjusted to the valve shaft 11 It is desirable that the ratio be at least three times the external dimension D1.

[0049]

As described in detail above, according to the first aspect of the present invention, by forcibly pulling the piston rod,
The pressure in the piston rod-side oil chamber is increased, and the pressure is guided to an annular oil chamber formed by expanding the oil passage, and is received by the annular oil chamber by a pressure receiving portion of a valve having a large pressure receiving area. As a result, a force acts on the valve body in a direction away from the piston by this pressure, so that the pressure acting on the annular oil chamber is increased and the force acting on the valve body in the direction away from the piston is applied to the gas chamber side. By increasing the force acting in the direction in which the valve body is seated on the piston by the pressure of the oil chamber, the valve body can be separated from the piston and the gas chamber side oil chamber and the piston rod side oil chamber can communicate with each other. it can.

Therefore, by continuing to pull the piston rod, the oil liquid can be circulated between the oil chambers through the oil passage and the piston rod can be extended from the cylinder, so that the operation of the operation pin is omitted. Thus, the amount of extension of the piston rod can be adjusted, the adjustment operation can be simplified, and the operability during handling can be improved.

According to the second aspect of the present invention, since the pressure guided to the annular oil chamber is received by the washer, the deformation of the O-ring due to this pressure can be prevented. Valve opening delay due to
Poor valve opening and the like can be prevented, and the valve body can be opened smoothly and reliably, and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a gas spring device according to an embodiment of the present invention.

FIG. 2 is an enlarged main part longitudinal sectional view showing a main part surrounded by a two-dot chain line in FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 gas spring device 2 cylinder 6 free piston (defining member) 7 piston 8 piston rod 9 oil passage 10 valve body 11 valve shaft 12 valve head 12B conical pressure receiving part 17 washer 18 operation pin A gas chamber B upper oil chamber ( Gas chamber side oil chamber) C Lower oil chamber (piston rod side oil chamber) E Annular oil chamber

Claims (2)

[Claims] 1. A cylinder filled with an oil liquid and a gas, a defining member slidably inserted into the cylinder and defining an oil chamber and a gas chamber in the cylinder, and a sliding member in the oil chamber. A piston movably inserted and defining the oil chamber into two chambers, a gas chamber-side oil chamber and a piston rod-side oil chamber, and a hollow end having one end connected to the piston and the other end extending out of the cylinder. A piston rod, an oil passage formed in the axial direction of the piston and communicating the gas chamber-side oil chamber and the piston rod-side oil chamber, and a valve shaft provided so as to be displaceable in the axial direction of the oil passage;
A valve body is provided in the hollow part of the piston rod for operating and operating the valve body that communicates and shuts off the gas chamber side oil chamber and the piston rod side oil chamber by the valve head being separated from and seated on the piston. In the gas spring device comprising: an operating pin, the piston is provided with an annular oil chamber surrounding the outer periphery of the valve shaft of the valve body by forming the oil passage to have a larger diameter. A gas spring device comprising a pressure receiving portion for receiving a pressure guided to the annular oil chamber. 2. An O-ring is provided on the outer periphery of the valve shaft of the valve body to maintain a liquid-tight relationship between the outer periphery of the valve shaft and the inner periphery of the hollow portion of the piston rod, and the annular oil is provided on one end side of the piston rod. 2. The gas spring device according to claim 1, further comprising a washer for receiving the pressure guided to the chamber and preventing the O-ring from receiving the pressure.