JPH02188652A - Sealing device - Google Patents

Abstract

PURPOSE:To restrict the leaking quantity of a seal and prolong the life of sealing members by providing a plurality of grooves at an interval larger than the relatively moving distance of a plurality of relatively moving parts like a cylinder and a piston and installing sealing members in these grooves. CONSTITUTION:Two installing grooves 34 for sealing members 31 are provided on a piston 3 with the length l1 of a partition wall 32 made longer than a piston stroke l2. Hence, when the piston 3 is reciprocated in the cylinder 2 at the stroke l2 by means of a crank mechanism 4, the lip 52 of each sealing member 31 will not overlap on the sliding face of the cylinder 2. Therefore, even if the thickness of the lip 52 of either sealing member 31 becomes zero doe to the dispersion of the thickness of the lip 52 of each sealing member 31 or the dispersion of the tensile force of metal springs 53 causing the metal spring 53 to be brought into contact with the cylinder 2, the lip 52 of the other sealing member 31 will not slide. Hence, the leaking quantity from the lip 52 can be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application on the Toryo] This invention relates to a sealing device for a short-stroke reciprocating compressor used in a gas compressor, a Stirling refrigerator, or the like.

[Conventional technology]

A conventional example of this type of sealing device will be explained using a reciprocating compressor of a Stirling refrigerator whose sectional view is shown in FIG.

In FIG. 3, a piston 3, which is a sliding body 3, is provided so as to be movable in a linear direction within a cylinder 2, which is a cylindrical body 2, provided on the main body frame 1. This piston 3 has two seal members 31, which will be described later, and a partition wall 32. It is installed with the minimum radial strength that can be maintained. Also, two guide members 33 are similarly attached, and the inside of the cylinder 2 is stroked 1. It is made to reciprocate with s. A cylinder head 21 is airtightly attached to the top of the cylinder 2, forming a compression space 22 between it and the top of the piston 3, and is connected to an expander (not shown) through a connection hole 23 of the cylinder head 21. .

Next, the structure of the sealing member 31 will be explained in detail with reference to the cross-sectional view of FIG. 2, which shows an enlarged portion of the portion surrounded by the dashed-dotted circle A in FIG. In FIG. 2, the sealing member 31 installed in the groove 34 of the piston 3 has a lip 52 with a U-shaped cross section made of synthetic resin such as Teflon, a non-metallic material that can slide without lubrication so as not to contaminate the working gas. and a metal spring 53 as an elastic member that applies tension to the lip 52 from the inside of the seal ring 51 and biases the U-shaped cross section of the seal ring 51 in the direction of opening. ing.

This lip 52 repeatedly slides without being airtight with the cylinder 2, causing wear. Due to this wear, the thickness of the lip 52 becomes zero or the thickness of the metal spring 53
When the tension force becomes O and the 2-blade 52 cannot be pressed against the cylinder 2, airtightness cannot be maintained and the life of the reciprocating compressor ends. For this reason, in long-life and disposable applications such as onboard satellites, the free diameter of the metal spring 53 when attached to the piston is determined by taking into account variations in the thickness of the lip 52 and variations in the tension force of the metal spring 53. By making the inner diameter larger than the inner diameter of the lip 52, the thickness of the lip 52 becomes 0.
We aim to maintain the sealing function by applying tension until the sealing temperature reaches 100°, extending the lifespan of the seal. Note that the metal spring 53 is a coil made of a spring steel wire wound in a long and narrow helical spring shape, and is installed inside the seal ring 51, and the broken line circle 53a indicates the free circular shape when installed. The cross-sectional shape of is shown.

In addition, by arranging a plurality of seal members 31 in series, the pressure of the working gas is shared by each seal member 31, and the contact surface pressure with the cylinder 2 per seal member 31 is reduced, so that the pressure per unit time is reduced. This reduces the amount of wear and allows for even longer life.

A sealing device with a sliding contact mechanism is constructed in which the sealing member 31 having the above-mentioned structure is mounted and contacted with a desired contact pressure to maintain airtightness.

[Problem to be solved by the invention]

However, the above-described sealing device has the following problems.

Separate multiple seal members 31! , a plurality of metal springs 53 are arranged in series in close proximity to each other, and in consideration of variations in the thickness of the lip 52 of each seal member 31 and variations in the tension force of the metal spring 53, the free diameter of the metal spring 53 when the piston is installed is Since the inner diameter of the lip 52 is larger than the inner diameter of the lip 52, tension force is applied until the thickness of the lip 52 becomes 0.
When the thickness of the lip 52 of any one of the sealing members 31 becomes O, there will be metal contact between the metal spring 53 and the cylinder 2 in that sealing member 31, and the cylinder 2 will be scratched. Therefore, other adjacent seal members 31
The lip 52 of the seal member 31 slides on this scratch, increasing the amount of leakage from the lip 52 of the seal member 31, accelerating the wear of the lip 52, and significantly hastening the loss of sealing function.

An object of the present invention is to provide a sealing device that eliminates the above-mentioned conventional drawbacks and can achieve a longer service life.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention combines two parts: a cylindrical body and a sliding body that fits inside the cylindrical body and can move relatively. A plurality of grooves are provided on the periphery of the fitting part of one of the parts and are perpendicular to the direction of movement of the fitting part, and within these grooves there is a U-shape that slides into contact with the opposing surface of the other part with a desired contact pressure to maintain airtightness. In a sealing device of a sliding contact tR structure equipped with a sealing member consisting of a seal ring made of an annular non-metallic material with a shaped cross section and an elastic body that biases the U-shaped cross section of the seal ring in the direction of opening, the relative movement A plurality of grooves are provided at intervals greater than the relative movement distance of the two parts, and the sealing member is attached to the liquid groove.

(Function) In this invention, due to variations in the thickness of the lip 52 of each seal member 31 and variations in the tension force of the metal spring 53, the thickness of the lip 52 of any one seal member 31 becomes O. Even if the metal spring 53 and the cylinder 2 come into metal contact and abrasion occurs on the cylinder 2, the adjacent seal member 31 will have a plurality of grooves in which the seal member is attached to prevent the two parts from moving relative to each other. Since they are provided at intervals greater than the relative movement distance, they will not slide over scratches.

Therefore, the amount of leakage of working gas from the lip 52 of the seal member 31 is not increased and wear is not accelerated.

〔Example〕

Embodiments of the invention will be described based on the drawings.

Note that the reference numbers of elements having the same functions as those in the prior art are the same.

FIG. 1 is a cross-sectional view of a reciprocating compressor showing an embodiment of the sealing device of the present invention. 32 length j! 1 is made longer and 2 pieces are provided.

With the above configuration, when the piston 3 is reciprocated within the cylinder 3 with a stroke ff1t by the crank mechanism 4 driven by a drive machine (not shown), the sliding surface of the cylinder 2 and the bottom 52 of each seal member 31 are do not overlap with each other. Therefore, due to variations in the thickness of the lip 52 of each seal member 31 and variations in the tension force of the metal spring 53, the thickness of the lip 52 of any one seal member 31 becomes 0. Even if a scratch occurs on the cylinder 2 due to metal contact between the metal spring 53 and the cylinder 2, the lip 52 of the other adjacent sealing member 31 will not slide on the scratch, so there will be no damage from the lip 52. The amount of leakage of the lip 52 is not increased, and the wear of the lip 52 is not accelerated and the sealing function is lost more quickly.

In this embodiment, the piston 3 has a mounting groove 3 for the seal member 31.
4, but grooves 34 are provided in the cylinder 2.
It is clear that it is possible.

〔Effect of the invention〕

According to this invention, a plurality of grooves perpendicular to the relative movement direction are provided in the opposing surfaces of the cylinder and piston that move relatively at intervals longer than the relative movement distance (viston stroke), and seal members are provided in these grooves. , due to variations in the thickness of the lips of each sealing member and variations in the tension of the metal spring, the thickness of the lip of any one sealing member becomes 0 and the metal spring and the cylinder come into metal contact, causing the cylinder to Even if a scratch occurs on the seal, the lips of other sealing members will not slide over the scratch. Therefore, due to variations in the thickness of the lips of each sealing member and variations in the tension force of the metal spring, Even after the sealing function of any one sealing member is lost, the sealing function of the other sealing members is not impaired, so a sealing device with a longer life can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a reciprocating compressor showing an embodiment of the sealing device of the present invention, and FIG. 2 is an enlarged view of a portion surrounded by a circle A of a dashed line in FIG. FIG. 3 is a sectional view of a reciprocating compressor showing a conventional example of a sealing device. l: Main body frame, 2: Cylindrical body (cylinder), 3: Sliding body (piston), 4: Crank mechanism, 21 cylinder head, 23: Compression space, 31: Seal member, 32.32
a: Partition wall, 33 guide member, 34: Groove, building horn Figure 1

Claims (1)

[Claims] 1) Combine two parts: a cylindrical body and a sliding body that fits into the inside of this cylindrical body and can move relatively, and attach a slider to the periphery of the fitting part of one of these two parts. A seal ring made of an annular non-metallic material with a U-shaped cross section, which has a plurality of grooves perpendicular to the direction of movement, and which slides into contact with the opposing surface of the other component with a desired contact pressure to maintain airtightness within these grooves. and an elastic body that biases the U-shaped cross section of the seal ring in the direction of opening. A sealing device characterized in that a plurality of grooves are provided in the grooves, and the sealing member is attached to the grooves.