JPS61197856A - Seal ring - Google Patents

Abstract

PURPOSE:To reduce the sliding resistance of seal ring thus to improve the durability by making a groove at the sliding section of seal ring then filling with lubricant. CONSTITUTION:A groove 3 is made circumferentially in the sliding section 2 of seal ring 1. Said groove 3 is filled with lubricant or gease 4 then fixed through an O-ring 5 to the piston 6 to be mounted between the piston 6 and the cylinder 7. When the seal ring 1 will slide on the inner wall 8 of cylinder, thin film of grease is formed between the sliding section 2 and the inner wall 8 of cylinder to provide grease lubrication. Consequently, the sliding resistance of seal ring 1 is reduced considerably.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a seal ring that prevents fluid leakage.

[Technical background of the invention and its problems]

For example, when a piston inserted into a cylinder moves due to a change in the pressure of a fluid such as oil or air inside the cylinder,
A sealing means is provided between the cylinder and the piston to prevent fluid from leaking therefrom. Rubber gaskets are mainly used in hydraulic equipment, and piston rings are used in internal combustion engines. These seals are very important because fluid leaks reduce the kinetic energy transferred to the piston, causing a loss of efficiency.

Since the above-mentioned seal slides on the outer circumference of the piston or the inner wall of the cylinder, a lubricant is usually used to prevent friction and wear as much as possible. However, under special environments, it may be difficult to use lubricants. For example, there is a piston seal for a He expansion engine installed in a He liquefaction refrigerator.

Conventionally, as shown in FIG. 6, this seal I was made of a resin material and was attached to the cylinder a3 so as to contact the cylinder a4 via an O-ring (13).At this time,
No lubricant is used and the seal αυ is often operated in a dry atmosphere.
-Slide back. This is because the He gas flowing into the cylinder (141) is at an extremely low temperature, so if the lubricant enters, it may freeze. Also, due to the function of the refrigerator, the lubricant may not mix into the He gas. This is because it is not desirable.

As described above, in an expansion engine, the seal is slid in a dry atmosphere, and in this case, in order to maintain the sealing property between the piston and the cylinder, a certain amount of interference is provided to the O-ring. As a result, the sliding resistance of the seal becomes considerably large, and even if the seal is made of a solid lubricant such as a resin material, the seal wears out quickly, resulting in functional deterioration. Furthermore, since the frictional force is large, the generation of frictional heat is large and has an adverse effect on the refrigeration system itself. It is an object of the present invention to provide a seal ring that reduces resistance, improves durability, and has good sealing performance.

[Summary of the invention]

The present invention provides a groove in the sliding part of a seal ring installed between a stationary part and a movable part such as a cylinder and a piston,
This seal ring is characterized in that this groove is filled with a lubricant. From this, the sliding condition of this seal ring is one in which the sealing performance is maintained well due to the thin film of lubricant filled in the groove. Note that the lubricant is sealed in the groove of the seal ring. Therefore, the leakage from the seal ring is very small.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 3 each show this embodiment. The sliding part (2) of the seal ring (1) has a groove (3) along the circumferential direction.
) is engraved. Roughly speaking, this groove (3) is filled with grease (4) as a lubricant, and is fixed to the piston (6) via the O-ring (5).
6) and the cylinder (7).

At this time, the O-ring (5) is tightened so as to press the seal ring (1) against the cylinder inner wall f8).

When the piston (5) moves in the axial direction in this state, the seal ring (1) slides on the cylinder inner wall (8), but at this time, the seal ring (1) is prevented from sliding by the grease (4) filled in the groove (3). A thin film of grease is formed between the moving part (2) and the cylinder inner wall (8) to provide grease lubrication.For this reason, the sliding resistance of the seal ring (1) is greater than when dry lubrication is applied. Reduced. Therefore, wear is reduced and durability is improved. Further, since a thin film is formed, there is no gap between the sliding portion (2) and the cylinder inner wall (8), and the sealing performance is improved. In addition, when this seal ring (1) is used in the expansion engine of a He refrigerator, the heat generation is also reduced, so it is possible to reduce heat intrusion into low-temperature parts. ), the grease (4) is sealed, so that leakage of the grease (4) to the outside of the seal ring (1) is minimized. Therefore, there is no fear that the grease (4) will enter the low temperature part and freeze.

[Modified example of the invention]

In the above embodiment, the seal ring is fixed to the piston, that is, the movable body, and is used for sliding on the outer diameter, but it may be fixed to the cylinder, that is, the stationary body, and used for sliding on the inner diameter. There may be not only one groove, but also two or more grooves. Furthermore, it can be used not only when the movable body moves linearly in the axial direction but also when it rotates. In this case, as shown in FIG.
It is effective to fill it with grease (4). Further, as shown in FIG. 5, the seal ring may have a two-stage structure of an upper part (1a) and a lower part (1b) in order to provide the groove (3). □In addition, although the case where it was used for the expansion engine of a He refrigerator was explained in the Example, it goes without saying that it is not limited to this and can be used for other equipment.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the embodiment, Fig. 2 is a partial sectional view showing the embodiment, Fig. 3 is a sectional view showing the main parts of the embodiment, and Fig. 4 is a perspective view showing the second embodiment. FIG. 5 is a perspective view showing the third embodiment, and FIG. 6 is a sectional view showing a conventional example. 1...Seal ring, 2...Sliding part, 3...Groove,
4...Grease. Figure 1 Figure 4 Figure 5 Figure 6 n

Claims (3)

[Claims] (1) A seal ring that is installed between a stationary body and a movable body to prevent fluid from leaking between the two has a groove in the sliding part of the seal ring, and this groove is filled with a lubricant. Seal ring. (2) The seal ring according to claim 1, wherein the lubricant is grease. (3) The seal ring according to claim 1, wherein the groove is carved into an integral seal ring.