JP2602424Y2 - Gas spring piston holding structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas spring piston holding structure in which a resin piston is fixedly held on a piston rod.

[0002]

2. Description of the Related Art A piston made of resin is easier to mold and less expensive than a piston made of sintered metal.
In addition, since it is lightweight, it is often applied to gas springs having a simple structure.

[0003] Many pistons of gas springs are caulked and fixed to the base end of a piston rod. If this piston is made of resin, its strength is lower than that of a sintered metal piston, so when a large caulking force acts on the piston, the piston will be deformed, and the piston will be attached diagonally to the piston rod, May be deformed, and the sliding performance of the piston may be reduced.

Therefore, when assembling the piston to the piston rod, a metal washer which receives a caulking force is installed on the piston.

[0005]

However, since the washer is separate from the piston, when the piston and the washer are inserted into the piston rod and assembled,
The washer must be supported to align the axis of the washer with the axis of the piston. For this reason, especially in an automatic assembly line, there is a possibility that the work efficiency of the work of assembling the piston may be reduced.

The present invention has been made in consideration of the above circumstances, and can improve the work efficiency of the assembling work of assembling the piston to the piston rod while ensuring the sliding performance of the piston. An object of the present invention is to provide a piston holding structure for a gas spring.

[0007]

According to the present invention, a piston having a piston rod fixedly held therein is slidably housed in a cylinder, and communicates between chambers on both sides defined by the piston.
In a gas spring provided with a flow path , the piston is made of resin, and a circumferential direction of one end face of the piston is
At a plurality of positions , do not overlap with the opening of the flow path, and
In the radial direction, a plurality of protrusions projecting inward in the radial direction are formed over a range of lengths arranged in a row, and a metal washer is press-fitted and held in advance between the tips of the plurality of protrusions, penetrating the piston and the washer. distal end of the piston rod that is caulked, the caulking force is this Pisutonro
Axial to the piston rod the piston together with the washer acts on the washer adjacent to the distal end of the head
It is fixed and held in the direction .

[0008]

Therefore, according to the piston holding structure of the gas spring according to the present invention, the caulking force of the piston rod acts on the metal washer and does not act on the resin piston, so that the piston is deformed by the caulking force, The piston is not attached obliquely to the piston rod, and the outer periphery of the piston is not deformed. For this reason,
Good sliding performance of the piston can be ensured.

Further, when assembling the piston to the piston rod, the washer is pressed into and held by a plurality of projections of the piston and is integrated with the piston, so that there is no need to support the washer when assembling the piston. As a result, the work efficiency of the assembling work for assembling the piston to the piston rod can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a gas spring to which an embodiment of a gas spring piston holding structure according to the present invention is applied. FIG. 2 is an enlarged sectional view showing a part of FIG. FIG. 3 is a sectional view showing the piston of FIG. FIG. 4 is a front view showing the piston of FIG.

The gas spring 10 shown in FIG. 1 supports, for example, a flap in a trunk room of a sedan type automobile or a rear door of a hatchback type automobile. The gas spring 10 includes a cylinder 11
A piston 12 and a free piston 13 are slidably housed therein, and a piston rod 14 is fixedly held by the piston 12. This piston rod 14 is guided by a rod guide 15 fitted to the open end of the cylinder 11.

The interior of the cylinder 11 is divided into a gas chamber 16 and an oil chamber 17 by a free piston 13.
2 further divides this oil chamber 17 into A oil chamber 17A and B oil chamber 17
Section B. The gas 18 is stored in the gas chamber 16 in the A oil chamber 17.
Oil 19 is sealed in the A and B oil chambers 17B, respectively.

The piston 12 and the free piston 1
3 is fitted with an O-ring 20, and the gas chamber 16, the A oil chamber 1
The 7A and B oil chambers 17B are configured in an air-tight state and a liquid-tight state.

The gas 18 in the gas chamber 16 causes the piston rod 14 to extend from the cylinder 11 in the direction of arrow A, and urges the gas spring 10 in the direction of extension.
With this urging force, the load on the flap in the trunk room and the load on the rear door of the hatchback type automobile are supported. When the gas spring 10 in which the piston rod 14 is housed in the cylinder 11 in the direction of arrow B contracts, the piston rod 14
, The gas chamber 16 moves the free piston 13 by an arrow B as much as the invading volume of the piston rod 14.
It moves in the direction to function as a volume compensation chamber.

As shown in FIG. 2, a step 22 is formed at the base end of the piston rod 14,
The piston 11 is fitted into the base end of the piston 4 together with the valve receiver 23, and is fixed and held as described later. At this time,
The valve receiver 23 comes into contact with the step 22, and a first valve 24 and a second valve 25 are arranged between the piston 12 and the valve receiver 23. The piston 12 has a piston-side flow path 26, and the valve receiver 23 has a valve-receiving-side flow path 2.
7 are drilled in the circumferential direction. Also, the second
A plurality of slits 28 are formed on the outer periphery of the valve 25.

When the gas spring 10 in which the piston rod 14 is accommodated in the direction of arrow B contracts, the oil 19 in the A oil chamber 17A flows through the piston side flow path 26, and the first valve 24 and the second valve 25 It is moved to the receiver 23 side and flows into the B oil chamber 17B from the gap between the outer periphery of the valve receiver 23 and the inner wall of the cylinder 11. The gas spring 10 in which the piston rod 14 extends in the direction of arrow A
When the oil is extended, the oil 19 in the B oil chamber 17B flows through the slit 28 from the valve receiving side flow path 27, and flows into the A oil chamber 17A via the piston side flow path 26. Oil 19
A hydraulic damping force is generated by the flow resistance while the gas flows through the orifice 28, and the extension of the gas spring 10 is suppressed.

The piston 12 is formed of resin. As shown in FIGS. 3 and 4, a recess 29 is formed in the piston 12 at one end surface on the A oil chamber 17A side.
A projection 30 is formed integrally with the piston 12 in the recess 29. A plurality of the protrusions 30 are provided in the circumferential direction of the piston 12,
It is formed to protrude radially inward of the piston 12.
A metal washer 31 is press-fitted into the plurality of projections 30 to be integrated.

The piston 12 and the washer 31 are respectively formed with through holes 32 and 33 through which the base end of the piston rod 14 passes. Washer 31 is piston 1
2, these through holes 32 and 3
The axes of 3 coincide. Piston 12 and valve receiver 2
When assembling the piston 1 into the piston rod, the washer 31 is integrated with the piston 12 and the piston 1
The base end of the piston rod 14 is passed through the through holes 32 and 33 of the washer 2 and the washer 31. In this state, the protruding portion 34 at the base end of the piston rod 14 is caulked, a caulking force is applied to the washer 31, and the piston 12 and the valve receiver are brought into contact with the valve receiver 23 against the step 22. 23 is fixedly held at the base end of the piston rod 14. Thus, the piston 12 and the valve receiver 23 are assembled to the piston rod 14.

According to the above embodiment, the piston rod 14
The caulking force of the projecting portion 34 acts on the metal washer 31 and does not act on the resin piston 12, so that the piston 12 is deformed by the caulking force and the piston 1
2 is not obliquely attached to the piston rod 14 and the outer periphery of the piston 12 is not deformed.
Therefore, good sliding performance of the piston 12 sliding in the piston rod 14 can be ensured.

The piston 12 is connected to a piston rod 14
Since the washer 31 is press-fitted and held by the plurality of projections 30 of the piston 12 and is integrated with the piston 12, it is not necessary to support the washer 31 when assembling the piston 12. As a result, the working efficiency of the assembling work for assembling the piston to the piston rod 14 can be improved. In particular, when the piston 12 is assembled to the piston rod 14 using an automatic assembly line, the work efficiency is significantly improved.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. Anything is included in the present invention.

[0022]

As described above, according to the piston holding structure of the gas spring according to the present invention, the working efficiency of the assembling work for assembling the piston to the piston rod is improved while ensuring the good sliding performance of the piston. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a gas spring to which an embodiment of a gas spring piston holding structure according to the present invention is applied.

FIG. 2 is an enlarged sectional view showing a part of FIG. 1;

FIG. 3 is a sectional view showing the piston of FIG. 2;

FIG. 4 is a front view showing the piston of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gas spring 11 Cylinder 12 Piston 14 Piston rod 16 Gas chamber 17A A oil chamber 17B B oil chamber 18 Gas 19 Oil 24 First valve 25 Second valve 30 Projection 31 Washer 34 Projection at base end of piston rod

Claims (1)

(57) [Scope of request for utility model registration] A piston having a piston rod fixedly held therein is slidably housed in a cylinder, and is separated by the piston.
In the gas spring provided with a flow path communicating the chambers on both sides defined, the piston is made of resin, and does not overlap with the opening of the flow path at a plurality of circumferential positions on one end surface of the piston .
A plurality of protrusions projecting radially inward over a range of lengths in the radial direction are formed in the opening, and a metal washer is press-fitted and held in advance between the tips of the plurality of protrusions. distal end of the piston rod passing through the washer is caulked, the caulking force is this
The piston holding structure of a gas spring, wherein the piston is fixedly held on the piston rod together with the washer by acting on the washer close to the tip of the piston rod .