JPS61197857A - Sealing mechanism - Google Patents

Abstract

PURPOSE:To suppress leakage of lubricant to the outside by securing a plurality of seal rings through supporting rings having grooves between them while filling lubricant between the seal rings. CONSTITUTION:Two seal rings 2a, 2b are provided to a piston 1. The seal rings 2a, 2b are secured through supporting rings 5 arranged between the piston 1. The supporting ring 5 is provided with a groove 6 etched in the circumferential face and the supporting sections 7a, 7b at the opposite ends. Lubricant 8 is filled in the groove 6 and between two seal rings 2a, 2b. since the lubricant 8 is sealed hermetically, it will never leak excessively to protect the peripheral machinaries from contamination.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a seal mechanism for preventing fluid leakage.

[Technical background of the invention and its problems]

For example, when the piston moves back and forth due to the pressure action of fluids such as oil or sudden air inside the cylinder, a seal between the piston and the cylinder is used to prevent fluid leakage. f 1) 6i (-H-I layer) There are various methods for sealing between a movable body and a stationary body, and an appropriate method is used depending on the equipment to be applied.For example, A non-contact labyrinth method is used for sealing between the turbine rotor and the casing, and a piston ring is used for the internal combustion engine piston, which slides back and forth on the inner wall of the cylinder using oil lubrication.Aside from the former non-contact method, the latter When a seal ring such as a piston ring slides on a mating wall surface, it is usually used while being lubricated with oil or grease to reduce friction and wear. However, it may be difficult to use lubricants.For example, if the fluid is liquid oxygen or cryogenic helium gas, the lubricant may freeze when it comes into contact with these fluids.
Instead of functioning as a lubricant, it damages the seal ring itself. Therefore, in such cases, dry lubrication has conventionally been performed using a solid lubricant such as a resin material for the seal ring. For example, in an expansion engine used in a helium liquefaction refrigerator, there is the above-mentioned problem, so a resin seal ring a3 is attached to the upper end of the piston αD via an O-ring 03, as shown in FIG. The helium gas in chamber I is sealed. At this time, the piston Q9 reciprocates in the axial direction due to the pressure action of the helium gas, so the seal ring az slides on the inner wall of the cylinder with dry lubrication.

In such a method, since the seal ring slides in contact with a solid surface under dry lubrication, abrasion powder may be generated. Also,
In the above-mentioned expansion engine, a margin is given to the O-ring to press the seal ring against the inner wall of the cylinder.
It has a structure that keeps fluid sealed. For this reason, the sliding resistance of the seal ring increases, which increases wear and causes problems in terms of service life.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a sealing mechanism in which a lubricant can be used not only in normal environments but also in special environments such as extremely low temperatures.

[Summary of the invention]

In the present invention, a plurality of seal rings are mounted with a support ring having a groove therebetween, and a lubricant is filled between the seal rings. According to this seal mechanism, when the seal ring slides on the mating sliding surface, it is lubricated by the lubricant, but this lubricant is sealed between the multiple seal rings, so it is not released to the outside. The lubricant leaks very little and does not contaminate the fluid or peripheral equipment. [Effects of the Invention] According to the sealing mechanism of the present invention, the lubricant does not contaminate the fluid to be sealed or the peripheral equipment. Therefore,
Despite using lubricants, it can be used in special environments such as extremely low temperatures, and can be used in a wide range of fields. In particular, in special environments such as those mentioned above, the lifespan and sealing performance are greatly improved compared to conventional products.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings. 1 and 2 show one embodiment of the invention. Two seal rings (2a) and (2b) are interposed in the piston (1). Further, the seal rings (2a L (2b) are each fixed by a support ring (5) installed between the piston (1).The support ring (5) has a groove (6) carved in the curved surface. and support portions (7a L (7b)) at both ends.The gaps between the support portions (7a), (7b) and the mating sliding surface are such that the seal rings (2a), (2b) are firmly fixed. Therefore, it is preferable that the clearance be the same as that of the piston (1). However, the seal ring (2aL (
2b) is not likely to fall off the piston (1),
The support part (
7a) and (7b) may be increased. On the other hand, groove (6)
A lubricant (8) is filled between the two seal rings (2a) and (2b). This lubricant (8) may be a highly viscous lubricating oil, but generally when a piston equipped with a sealing mechanism having such a configuration reciprocates,
The lubricant (8) adheres to the sliding surface of the cylinder (3) and seals the ring (2a).

A thin film is formed between (2b) and the sliding surface to lubricate the seal rings (2a) and (2b). For this reason, the seal ring (2a L (2b)) has better fluid sealing performance than dry lubrication, and furthermore, the sliding resistance is reduced and the amount of wear is extremely small, so the service life is dramatically improved.

In addition, the lubricant (8) is attached to the seal rings (2a) and (2b).
Since each space is filled and sealed, no more than the necessary amount leaks outside, and only the required amount adheres to the sliding surface. Therefore,
The sealing fluid or the cylinder (3) and other peripheral equipment are not contaminated by the lubricant (8). Therefore, it can be used satisfactorily even when the sealing fluid is cryogenic helium gas, such as in an expansion engine for a He liquefaction refrigerator, and it is not desirable for impurities to be mixed into the helium gas. Also, Nuru Uskashi H old horse mackerel 11 So Il pull old hook 2 by Ryu 1 (7b) 2
Since the seal rings (2a) and (2b) are fixedly inserted, stable sliding movement is always possible. Furthermore, by providing the groove (6), the amount of lubricant (8) filled can be increased. Therefore, even if some abrasion powder from the seal rings (2a) and (2b) mixes into the lubricant (8), the mixing density is reduced and the function as a lubricant can be maintained for a long time.

[Other Examples]

In the above-mentioned embodiment, the seal mechanism was provided on the piston side for outer diameter sliding, but as shown in FIG. 3, it may be attached to the cylinder side and used for inner diameter sliding. In this case, since the lubricant (8) is filled on the stationary body side, the lubricant (8)
It has the advantage of excellent sealing properties.

Further, the seal ring is not limited to the above example, and any type may be used. Furthermore, three or more seal rings may be provided, each with a support ring provided therebetween.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view showing an embodiment, Fig. 2 is a sectional view showing a support ring, Fig. 3 is a sectional view showing another embodiment, and Fig. 4 is a sectional view showing a support ring.
The figure is a front view showing a conventional example. 2at2b... Seal ring, 5... Support ring,
6...Groove, 8...Lubricant. Representative Patent Attorney Kensuke Chika (and 1 other person) No. 1
Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) In a seal mechanism that prevents fluid leakage between a movable body and a stationary body, a plurality of seal rings are installed with a support ring having a groove between them, and lubrication is applied between the seal rings. A sealing mechanism characterized by being filled with an agent. (2) The sealing mechanism according to claim 1, wherein the lubricant is grease.