JP2545177Y2 - Resin piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a piston used for a gas separation type pressure vessel or the like.

(Prior Art) Conventionally, as a pressure vessel used in a vehicle or the like, as shown in FIG. 4, for example, a piston 52 is slidably fitted in an outer case 51 and an oil chamber S1 is formed in the outer case 51. And a gas chamber S2, an oil chamber S1 is filled with hydraulic oil, and a gas chamber S2 is filled with high-pressure nitrogen gas. The piston 52 of this pressure vessel is generally formed of a non-ferrous metal such as iron or aluminum, and an O-ring 53 is fitted on the outer peripheral surface of the piston 52 to seal the inner peripheral surface of the outer case 51. doing.

(Problems to be Solved by the Invention) However, when the piston is formed from ferrous or non-ferrous metal, the material is cut, forged, and the groove of the O-ring is formed. In order to improve the quality, surface treatment must be performed, and the processing cost increases. Therefore, it is conceivable to mold the piston with resin.

However, when the piston is formed of resin, a force in the direction of inflating the piston acts due to the gas pressure of the gas chamber, and particularly when a resin having a small Young's modulus is used, poor sliding of the piston may occur. Therefore, the thickness of the piston must be increased.

(Means for Solving the Problems) In order to solve the problems described above, the present invention provides a piston body and a skirt portion extending from the piston body in a sliding direction and having a smaller outer diameter than the piston body. And a plurality of ridges formed on the outer peripheral surface of the skirt along the sliding direction and slidably contacting the inner peripheral surface of the case. The piston body, the skirt and the ridge are integrally formed. As a resin molded product, a clearance was formed between the outer peripheral surface of the skirt and the inner peripheral surface of the case so as to have the same pressure as the internal pressure of the skirt.

(Operation) Since the piston is made of integrally molded resin, no additional processing is required, the weight is reduced and the responsiveness is improved. In addition, the skirt outer peripheral surface is provided with a plurality of protrusions which are in sliding contact with the outer case inner peripheral surface. Since the gas is formed, the gas having the internal pressure of the skirt flows into the gap between the outer peripheral surface of the skirt portion of the piston and the inner peripheral surface of the outer case, and the pressure becomes the same as that of the gas chamber, so that the skirt portion does not expand.

(Embodiment) An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view of a pressure vessel provided with a piston according to the present invention, FIG. 2 is a view showing a main part of FIG. 1, and FIG. 3 is an external perspective view of the piston.

The pressure vessel 1 has a piston 3 slidably fitted in an outer case 2 having a closed bottom to define an oil chamber S1 and a gas chamber S2. The oil chamber S1 is filled with hydraulic oil, and a gas chamber is filled. Chisso gas is sealed in S2. The piston 3 is formed of resin, and the outer diameter of the skirt 4 is made slightly smaller than the inner diameter of the outer case 2. By providing a plurality of protrusions 5 that are in sliding contact with each other, the cross-sectional shape of the skirt portion 4 is formed in a petal shape or a gear shape as shown in FIG.
A clearance (gap) 6 having the same pressure as the gas chamber S2 is provided between the outer peripheral surface of the skirt portion 4 and the inner peripheral surface of the outer case 2.

A seal ring 7 for sealing between the outer peripheral surface of the piston 3 and the inner peripheral surface of the outer case 2 is fitted between the washers 8 and 8, and a cap 9 is screwed on an open end of the outer case 2. A seal ring 10 for sealing between the outer peripheral surface of the cap 9 and the inner peripheral surface of the outer case 2 is fitted and hermetically fixed, and an oil passage 11 communicating with the oil chamber S1 is provided in the cap 9. A plug 12 for sealing the gas filling hole is mounted on the bottom of the outer case 2.

As described above, since the piston 3 is formed of resin, no additional processing is required and the weight is reduced. The skirt portion 4 of the piston 3 has a petal shape or a gear shape in cross section, and a clearance 6 is provided between the skirt portion 4 and the inner peripheral surface of the outer case 2. Even if a force P in the direction of inflating the piston 3 acts as shown by the arrow in FIG. 1 due to the gas pressure, the gas in the gas chamber S2 flows into the clearance 6 and has the same pressure as the gas chamber S2. Therefore, the skirt portion 4 of the piston 3 does not expand.

(Effects of the Invention) As described above, the present invention provides a piston body, a skirt portion extending from the piston body in the sliding direction and having a smaller outer diameter than the piston body, and a skirt portion. A resin molded product consisting of a plurality of ridges provided on the outer peripheral surface along the sliding direction and slidably contacting the inner peripheral surface of the outer case.The piston body, skirt and ridges are integrally molded. The clearance between the outer peripheral surface of the skirt and the inner peripheral surface of the outer case has the same pressure as the internal pressure of the skirt, so no additional work is required, the cost is reduced, and the weight is reduced and the response is reduced. The performance is improved. Further, the skirt portion does not swell and malfunction does not occur, so that the thickness of the piston skirt portion can be reduced as in the case where the piston is formed of metal.

[Brief description of the drawings]

FIG. 1 is a sectional view of a pressure vessel having a piston according to the present invention, FIG. 2 is a view showing a main part of FIG. 1, FIG. 3 is an external perspective view of the piston, and FIG. It is sectional drawing of the pressure container provided with. In the drawings, 1 is a pressure vessel, 2 is an outer case (case), 3 is a piston, 3a is a piston body, 4 is a skirt, 5 is a protrusion (protrusion), 6 is clearance, 9 is a cap, 12 is a plug and S2 is a gas chamber.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho-61-40556 (JP, U) Japanese Utility Model Sho-55-35339 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] A piston slidably fitted in a case, the piston includes a piston body and a skirt portion extending from the piston body in a sliding direction and having a smaller outer diameter than the piston body. And a plurality of ridges provided on the outer peripheral surface of the skirt along the sliding direction and slidably in contact with the inner peripheral surface of the case, and a resin in which the piston body, the skirt, and the ridge are integrally formed. A resin piston, which is a molded product, wherein a clearance is formed between the outer peripheral surface of the skirt portion and the inner peripheral surface of the case so as to have the same pressure as the internal pressure of the skirt portion.