JPS6040911Y2 - gas spring - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a gas spring used in an opening/closing assistance device for a back door of an automobile, etc., which opens and closes by flipping upward.

A conventional gas spring is constructed as shown in FIG.

To explain this, 1 is a cylinder whose one end 1a is sealed with a cap 2 and into which working gas is filled under pressure, and 3 is a cylinder that slides a guide member 4 that seals the other end 1b of the cylinder 1. A piston rod penetrating through the cylinder 1, 5 is a sealing member for sealing between the guide member 4 and the piston rod 3, and 6 is fixed to the tip of the piston rod 3. This piston 6 has an orifice 9 formed therethrough that communicates with both gas chambers 7 and 8.

Further, reference numerals 10 and 11 are mounting members connected to the vehicle body side and back door of an automobile (not shown), respectively.

The gas spring configured in this manner pushes the piston rod 3 to open the back door while receiving flow resistance from the orifice 9 of the piston 6 when the back door is opened, due to the difference in pressure receiving area between the upper and lower surfaces of the piston 6. It is easy to operate and has the function of maintaining the most extended position where the piston 6 contacts the stop portion 12, that is, the open position of the back door.

When the back door is closed, a predetermined external force for closing the back door is applied, so that the piston rod 3 or the piston 6 moves downward while experiencing flow resistance from the orifice 9 of the piston 6, and gas pressure is generated corresponding to the intrusion volume of the piston rod 3. This prevents the bank door from closing suddenly and allows it to close slowly.

However, in such conventional gas springs, when the gas pressure inside the cylinder 1 decreases due to a drop in outside temperature or gas leakage, a predetermined gas reaction force cannot be obtained and the supporting force decreases. However, there was a problem in that the opened back door could no longer be maintained in the open state, and the back door would close inadvertently due to its own weight.

The present invention was developed in view of the above-mentioned drawbacks of the conventional art, and includes a valve provided in the piston or piston rod for opening and closing a communication hole between two gas chambers separated by the piston. is biased by a spring that opposes the gas pressure in one of the gas chambers, so that when the gas pressure decreases and the gas reaction force decreases, the valve closes the communication hole and backs up from the fully open state. To provide a gas spring which prevents a door from being closed inadvertently.

Embodiments of the present invention will be described in detail below based on the drawings.

2 to 5 show an embodiment thereof, and 20 is a long piston body screwed onto the tip of the piston rod 3 similar to the above, and the tip of the piston body 20 has a large diameter. , a seal ring 21 is fitted around the outer periphery.

An elongated hole 22 for accommodating a valve to be described later is provided from the tip to the center of the piston body 20, and a dish-shaped bushing 23 and a bushing 24 are installed in this elongated hole 22 so as to be connected to each other, and these are attached to a valve seat. Plate 2 is caulked to the opening of elongated hole 22 via 25.
6 is maintained.

27 is a rod-shaped valve with a conical head, the body of which is slidably supported through the bushes 23 and 24;
The head closes the valve hole 28 of the valve seat 25 in an openable and closable manner.

Further, a valve spring 30 is provided at the bottom of the elongated hole 22 to elastically support the valve plate 29, so that the valve plate 29 urges the valve 27 toward the valve seal 25.

31 is a bearing of the valve 27 provided in the bushing 24, and 32 is a seal ring that seals the bushing 24 and the valve 27.

33 and 34 are orifices that communicate with the circumferential walls of the bushing 23 and the piston body 20, and 35 is a through hole provided in the plate 26. A communicating hole is formed.

36 is a stopper for the piston body 20 installed inside the cylinder 1.

Next, the operation of the gas spring having such a configuration will be described.

First, when opening/closing the back door, if the gas pressure P1 in the gas chamber 8 is balanced with the load of the valve spring 30, the head of the valve 27 will move from the valve hole 28 of the valve seat 25 as shown in FIG. They are far apart as shown in .

In other words, the valve 27 opens the communication hole when the gas pressure is 21 or higher.

Therefore, the piston body 20 can freely slide within the cylinder 1 together with the piston rod 3 while being subjected to gas flow resistance from the orifices 33,34.

Thus, the gas spring has the function of assisting the opening/closing operation of the back door and maintaining the door position during that time by the gas reaction force generated corresponding to the volume of the piston rod 3 entering the cylinder 1 and the above-mentioned flow resistance. .

The straight line X in FIG. 5 shows the relationship between the stroke of the piston rod and the gas reaction force when the gas spring operates normally as described above.

Next, due to a drop in outside air temperature or a gas leak,
When the gas pressure in the gas chambers 7 and 8 decreases, for example, when the gas pressure decreases from Pl by ΔP to P2,
The balance between the gas pressure P1 and the load on the valve spring 30 is lost, and the valve spring 30
7 to the valve seat 25 as shown in FIGS. 2 and 4.
Push it to the side.

Therefore, the head of the valve 27 contacts and closes the valve hole 28 of the valve seat 25, and the piston rod 3
It acts to lock the movement within the cylinder 1.

In such a state, the piston rod 3 is connected to the cylinder 1.
When pushed into the cylinder, the area that receives pressure is cylinder 1.
The inner diameter area Sa (shaded area in Figure 4) is generated, and the generated force at that time is P2 x Sa, which generates a high reaction force that holds the back door and prevents the bag from accidentally falling due to its own weight. .

Here, when an external force is applied to close the door and the piston rod 3 is pushed in, the gas IEP2 in the gas chamber 8 rises, and when the gas pressure reaches Pl, the gas pressure P1 and the load of the valve spring 30 are The balance is maintained, the valve 27 opens the valve hole 28, the lock is released, gas flows from the gas chamber 8 to the gas chamber 7, and the desired opening/closing of the back door is assisted.

The characteristic of gas pressure in such a pressure drop state is shown by curve Y in FIG.

In this case, in addition to a coil spring, any spring body with a small spring constant, such as a disc spring or fluid pressure means, can be used as the valve spring 30.

Furthermore, in order to improve the sealing performance between the bushes 23 and 24 and the piston body 20, it is possible to apply a sealant between them, insert an O-ring between them, or integrally connect the two by press-fitting. You can also do it.

In this way, the piston body that slides inside the cylinder is provided with the valve 27 that balances the gas pressure at all times, and when the gas pressure inside the cylinder 1 decreases, the valve 27 is provided through the orifice 33, 34 provided in the piston body 20. , the flow of gas between the two gas chambers 7 and 8 separated by the piston body 20 is stopped, and further sliding of the piston body 20 with respect to the cylinder 1 is stopped.

Further, the stopping force is determined by the relationship with the cross-sectional area of the inner diameter of the cylinder 1.

Therefore, when this gas spring is attached to the bank door opening/closing assistance device, it is possible to prevent the back door from falling suddenly when it is fully opened, and safety is ensured.

It goes without saying that such a gas spring can be used not only for one bank door of an automobile, but also as an opening/closing aid for any opening/closing device or a height adjustment device for desks, chairs, etc.

FIG. 6 shows another embodiment of the present invention.

This differs from FIGS. 2 to 4 in that the valve 27 is directly slid tightly into the elongated hole 22 in the piston rod 3, and the valve spring 3 is directly inserted into the valve spring 27 without going through the valve plate.
This means that it was energized at 0.

For this reason, a disk-shaped piston 20A having a seal ring 21 around it is attached to the tip of the piston rod 3.

According to this, although the configuration is simple, the same effects as described above can be obtained.

Note that 37 is a seal ring that seals the valve 27 and the elongated hole 22.

FIG. 7 shows still another embodiment of the gas spring according to the present invention.

This is a simpler version of the one shown in FIG. 6, in which a through hole 38 and an orifice 4 are formed in the elongated hole 22 provided in the piston rod 3 and together with the orifice 34 form a communicating hole.
1, and a valve 27 biased by a valve spring 30 is slidably mounted in a through hole 38 of this valve seat 39.

Moreover, 40 is two seal rings that seal the valve 27 and the valve seat 39, and is provided in a position to sandwich an orifice 41 provided in the valve seat 39.

Such a gas spring allows gas to move between the gas chambers 7 and 8 when the gas pressure is high and the left end face of the valve faces the orifice 41, that is, during normal operation.
When the gas pressure decreases, the orifice 41 is closed as shown in FIG. 7 to stop the piston rod 3 from entering the cylinder 1 any further.

As explained above, according to the present invention, a piston rod is protruded through one end of a cylinder filled with working gas, and two movable parts are formed inside the cylinder at one end of the piston rod and are slidable. If the pressure in the gas chamber decreases for some reason by fixing the piston and providing the piston or piston rod with a communication hole between the two units and a valve means that opens and closes the communication hole according to the working gas pressure. However, the valve closes the communication hole to prevent the working gas from flowing, thereby stopping the movement of the piston rod into and out of the cylinder.

Thus, when such a gas spring is used as an opening/closing assist device for a back door of an automobile, it is possible to prevent the back door from accidentally dropping suddenly from the most extended position of the piston rod, that is, the open/close holding position of the back door.

In addition, the communication hole is automatically unblocked by increasing the gas pressure within the cylinder by applying an external force to the piston rod or the like, so the operation can be performed extremely easily.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional gas spring, Fig. 2 is a sectional view of a gas spring according to the present invention, and Figs.
The figure is also a sectional view of the main parts showing the operation of each valve according to the difference in gas pressure in the gas chamber, Figure 5 is a characteristic diagram of the gas reaction force during each operation, and Figure 6 is a gas spring according to the present invention. FIG. 7 is a sectional view of a main part of still another embodiment. 1...Cylinder, 3...Piston rod, 7゜8...Gas chamber, 20. 20 A--
-----Piston, 22...Elongated hole, 23.24
......Orifice, 25...Valve seat, 27...Valve, 28...Valve L29...Valve plate, 30...・・・
valve spring.

Claims (1)

[Scope of utility model registration request] A piston rod is protruded through one end of a cylinder filled with working gas, and a slidable piston with two chambers separated into two chambers is attached to the fixed hip piston or piston rod at one end of the piston rod. A gas spring comprising a communication hole between chambers and a valve means for opening and closing the communication hole in accordance with the working gas pressure.