JPH0719346A - Sealing member - Google Patents

Abstract

PURPOSE:To improve the sealing performance and the fitting performance of a sealing member for sealing the clearance between a cylinder and a piston without using lubricating oil. CONSTITUTION:Since a sealing member consists of a C-shaped backup ring 42 having a disconnect part 42g and a seal ring 41, which is provided with a halved joint-like disconnect part 41g and a projection 41b capable of being fitted into the disconnect part 42g, and the inner diameter of which is formed to be smaller than the outer diameter of the backup ring 42, the sealing member is loaded in a ring-shaped groove (not shown) of a piston by fitting the projection 41b into the disconnect part 42g. Thus, the seal ring 41 is subjected to radially expansion stress from the backup ring 42, and the inner peripheral surface 41a of the seal ring 41 is pressed against the inner peripheral surface of a cylinder to seal the clearance between the piston and the cylinder (not shown). Since the projection 41b is fitted into the disconnect part 42g to be positioned, there is no possibility that the disconnect part 41g is lapped over the disconnect part 42g to form a gas-leaking passage, and thus impair the sealing performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal member for sealing a gap formed between a cylinder and a piston without using lubricating oil.

[0002]

2. Description of the Related Art In a cryogenic refrigerator using helium gas or the like as a refrigerant, for example, a Gifode-McMahon refrigerator, a Stirling refrigerator, a Birmya refrigerator, etc., a temperature much lower than the melting point of the lubricating oil, for example, Since it is cooled to 10 K or less, if lubricating oil is used for the seal portion, the lubricating oil will solidify during the cooling operation, and smooth piston movement will be impaired. For this reason, in this type of device, lubricating oil cannot be used, and therefore, the gap formed between the cylinder and the piston is normally sealed by a non-lubricating type seal member.

The sealing member 7 illustrated in FIG. 6 shows an example of sealing means in, for example, a Gifode-McMahon type cryogenic refrigerator. The seal member 7 includes a ring-shaped resin seal ring 71 having a discontinuous joint-shaped discontinuous portion 71g, and the seal ring 71.
And a backup ring 72 made of, for example, stainless steel and formed in a C shape with a discontinuous portion 72g mounted inside the backup ring 72. The outer diameter is formed to be larger than the inner diameter of the seal ring 71.

As shown in FIGS. 7 and 8, the seal member 7 having the above-described structure has a seal ring 71 in the annular groove 2 formed on the outer peripheral surface of the displacer 1 functioning as a piston.
When the non-continuous portion 71g of the backup ring 72 and the non-continuous portion 72g of the backup ring 72 are mounted in a state of being displaced by 180 degrees, for example, the outer diameter of the backup ring 72 is the seal ring 71 when not mounted. Since the inner diameter of the seal ring 71 is larger than the inner diameter of the seal ring 71, a stress that expands the diameter of the seal ring 71 is applied from the backup ring 72.
1a comes into close contact with the inner peripheral surface 3a of the cylinder 3, and the amount of helium gas flowing through the gap G between the displacer 1 and the cylinder 3 decreases.

However, in the seal member 7 having the above-described structure, the seal ring 71 and the like gradually rotate during operation of the refrigerator, so that the discontinuous portion 71g of the seal ring 71 and the discontinuous portion 72g of the backup ring 72 become uniform. However, there is a problem that a route of gas leak occurs and the sealing property is deteriorated.

Further, in Japanese Unexamined Patent Publication No. 4-36370, as shown in FIG. 9, in the annular groove 2 formed on the outer peripheral surface of the displacer 1, a discontinuous portion similar to the discontinuous joint-shaped discontinuous portion 71g. A resin-made seal ring 81 (not shown), which is mounted inside the seal ring 81 and presses the seal ring 81 against the inner peripheral surface 3 a of the cylinder 3.
For example, a spring ring 82 made of stainless steel and having a discontinuous portion (not shown) similar to the discontinuous portion 72g,
One of the opposing side walls 2 that defines the axial width of the annular groove 2
1 and the seal ring 81 and presses the seal ring 81 against the other side wall 22, for example a spring ring 8 made of stainless steel with a discontinuity (not shown).
The seal member 8 composed of 3 and 3 is disclosed.

As the spring ring 83, one having a force that constantly pushes the seal ring 81 against the side wall 22 is used without being influenced by the movement of the displacer 1.

With such a structure, the seal ring 81 is biased by the spring ring 83, a gap is not formed between the side wall 22 and the seal ring 81, and a gas leak passage is not formed. As a result, it is said that gas leakage at the seal member 8 can be greatly reduced and the refrigerating capacity can be significantly improved.

However, since the seal member 8 has a structure in which the seal ring 81 is pressed in two directions by using the two spring rings 82 and 83, it is troublesome to mount it. was there.

[0010]

That is, as described above, none of the conventional seal members are satisfactory, so that there has been a problem to develop a seal member having excellent sealability and mountability.

[0011]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention comprises an annular groove formed in the outer peripheral surface of a piston and a discontinuous joint-shaped discontinuous portion. In a seal member including a seal ring to be mounted and a backup ring mounted inside the seal ring to apply a diametrical stress to the seal ring, the seal ring is separated from the discontinuous joint-like discontinuous portion. The seal is formed by providing a protrusion on the inner peripheral surface of the above-mentioned portion, and the backup ring is formed in a C-shape by one discontinuous portion that allows the protrusion of the seal ring to be fitted therein. Members,

[0012] A pair of seal rings, which are arranged in parallel with each other with their one end faces in contact with an annular groove formed on the outer peripheral surface of the piston, are mounted inside the pair of seal rings to give a bulging stress to the seal rings. In a seal member composed of a backup ring, the contact member end surfaces of the pair of seal rings are formed into slidable inclined surfaces,

A pair of seal rings, which are arranged side by side in a non-contact state in an annular groove formed on the outer peripheral surface of the piston, and a third seal ring which is mounted inside by contacting the pair of seal rings, In a seal member including a backup ring mounted inside the third seal ring and applying a bulging stress to the seal ring, each of the pair of seal rings has an outer peripheral surface in contact with an inner peripheral surface of the cylinder. An end surface in contact with the opposing side wall defining the axial width of the annular groove, and an inclined inner surface, wherein the third seal ring is slidable on each of the inclined surfaces of the pair of seal rings. And a sealing member formed by including an angled sloped surface in contact with each other.
This is to solve the above-mentioned problems of the conventional technology.

[0014]

According to the present invention, when the seal ring is mounted in the annular groove formed on the outer peripheral surface of the piston, the seal ring receives a bulging stress from the backup ring mounted inside, and the outer peripheral surface of the seal ring is It is pressed against the inner peripheral surface and seals the gap between the piston and the cylinder. Moreover, the seal ring and the backup ring are positioned such that the protrusions of the seal ring are fitted into the discontinuous portion of the backup ring, so that the discontinuous joint-like discontinuous portion of the seal ring and the non-continuous portion of the backup ring do not operate during operation. There is no concern that the continuous portion will overlap to form a gas leakage passage.

According to the second aspect of the present invention, when the piston is mounted in the annular groove formed on the outer peripheral surface of the piston, one of the pair of seal rings comes into contact with the backup ring which gives a diametrical stress, and the other of the pair of seal rings inside the cylinder. The end faces of the pair of seal rings that are not in contact with each other are pressed against the peripheral surfaces, and are pressed against the opposing side walls that define the axial width of the annular groove, thereby sealing the gap between the piston and the cylinder.

According to a third aspect of the present invention, when mounted in an annular groove formed on the outer peripheral surface of the piston, the third seal ring expands due to the stress applied by the backup ring, and the pair of seal rings has the expanded diameter. The slidable surfaces of the third seal ring slide in directions away from each other, the outer peripheral surfaces of the third seal ring are pressed against the inner peripheral surface of the cylinder, and the respective end surfaces of the third seal ring have an axial width of the annular groove. The gap between the piston and the cylinder is sealed by being pressed by the opposing side wall that defines it.

[0017]

Embodiments of the present invention will be described in detail below with reference to FIGS. In these figures, FIG.
The parts denoted by the same reference numerals as those in FIG.
This is a part having the same function as the part described with reference to FIG. 9, and description thereof is omitted within the range that does not hinder the understanding of the present invention. Also, the structure and function of the refrigerator itself equipped with the seal member of the present invention are not directly related to the present invention, and therefore the description thereof is omitted.

(Embodiment 1) The seal member 4 according to the first embodiment shown in FIG. 1 includes a seal ring 41 formed of a resin having excellent low temperature strength and lubrication characteristics, such as silicone resin, and the inside thereof. And a non-continuous portion 42g similar to the non-continuous portion 72g of the backup ring 72 in the seal member 7, and When not mounted, the seal ring 41 is formed in a C shape having an outer diameter larger than the inner diameter of the seal ring 41, and the other seal ring 41 has the same discontinuity as the discontinuous portion 71g of the seal ring 71 in the seal member 7. The backup ring 4 is provided on the inner peripheral surface of the joint-shaped discontinuous portion 41g and a portion separated from the discontinuous portion 41g, for example, a portion displaced by 180 degrees. It is formed with a fittable protrusions 41b discontinuous portion 42g of the.

Therefore, the seal member 4 of the present invention is provided in the annular groove 2 of the displacer 1 shown in FIG. 7 and FIG.
The protrusion 41b of the seal ring 41 is replaced by the backup ring 4
When the seal ring 41 is fitted in the second discontinuous portion 42g, the seal ring 41 receives a stress of increasing the diameter, that is, a bulging stress, from the large-diameter backup ring 42 mounted inside, and the outer peripheral surface 41a of the seal ring 41 Is pressed against the inner peripheral surface 3a of the cylinder 3 to displace the displacer 1 and the cylinder 3
The gap G between and is sealed.

Moreover, since the projection 41b of the seal ring 41 is fitted and positioned between the seal ring 41 and the backup ring 42 in the discontinuous portion 42g of the backup ring 42, the discontinuous joint of the seal ring 41 during operation. -Shaped discontinuous portion 41g and backup ring 42
There is no concern that the gas leak passage is formed by overlapping with the non-continuous portion 42g and the sealability is impaired.

(Embodiment 2) A seal member 5 according to a second embodiment shown in FIG. 2 comprises a pair of seal rings 5 arranged in parallel.
1 and 52, and a backup ring 53 mounted inside this.

The pair of seal rings 51, 52 are provided with a discontinuous portion (not shown) similar to the discontinuous joint-shaped discontinuous portion 41g, and are excellent in low-temperature strength and lubricating characteristics of, for example, silicone resin. The resin is formed so that the end surfaces 51a and 52a on the side in contact with each other are slidably slanted and are slightly wider than the width of the annular groove 2 to be mounted. Therefore, the end faces 51a and 52a are in contact with the annular groove 2 of the displacer 1 and the like, and the pair of seal rings 5
When the two are arranged side by side, the seal ring 52 enters the inner side of the annular groove 2 and the seal ring 51 is arranged in the front.

On the other hand, the backup ring 53, like the backup ring 42, is formed in a C shape with a discontinuous portion (not shown) made of stainless steel or the like. The outer diameter of the backup ring 53 is larger than the inner diameters of the pair of seal rings 51 and 52 when not mounted.

For this reason, the backup ring 53 is mounted in the annular groove 2, and a pair of seal rings 51, 52 are provided on the backup ring 53.
When they are arranged side by side, the inner peripheral surface 52b of the seal ring 52 comes into contact with the outer peripheral surface 53a of the backup ring 53 and receives the bulging stress F.

Then, the pair of seal rings 51, 52
Are slidably in contact with each other via the inclined end surfaces 51a and 52a, and therefore, by receiving the bulging stress F from the backup ring 53, the pair of seal rings 51
52 not only expands in diameter, but the seal ring 51 receives a stress to move it in the direction D1 side, and the seal ring 52 receives a similar stress in the direction D2.

As a result, the outer peripheral surface 5 of the seal ring 51 is
1b is pressed against the inner peripheral surface 3a of the cylinder 3, the remaining end surface 51c is pressed against the side wall 21 of the annular groove 2, and the remaining end surface 52c of the seal ring 52 is pressed against the other side wall 22 of the annular groove 2,
The upper and lower sides of the gap G formed between the displacer 1 and the cylinder 3 are completely sealed by the seal member 5 including the pair of seal rings 51 and 52 and the backup ring 53.

(Embodiment 3) A seal member 6 according to a third embodiment shown in FIG. 3 includes a pair of seal rings 61 and 62 arranged side by side in a non-contact state, and a third ring mounted inside the seal rings 61 and 62. The seal ring 63 and the backup ring 64 mounted inside the seal ring 63.

The pair of seal rings 61 and 62 and the third seal ring 63 form the discontinuous joint-shaped discontinuous portion 4 described above.
A pair of seal rings 61 is provided with a discontinuous portion (not shown) similar to that of 1 g, and is formed of a resin having excellent low temperature strength and lubrication characteristics, such as silicone resin, like the seal rings 41. Each of 62 includes an outer peripheral surface 61a and 62a that contacts the inner peripheral surface 3a of the cylinder 3, end surfaces 61b and 62b that contact the opposite side walls 21 and 22 that define the axial width of the annular groove 2, and inclined surfaces 61c and 62c. , And the third seal ring 63 has an inclined surface 61c of the pair of seal rings 61, 62 on the outer peripheral surface side.
.A mountain-shaped inclined surface 63 slidably in contact with each of 62c
a is formed.

On the other hand, the backup ring 64, like the backup ring 42, is formed in a C shape with a discontinuous portion (not shown) made of stainless steel or the like. Further, the outer diameter of the backup ring 64 is larger than the inner diameter of the third seal ring 63 in the non-attached state.

For this reason, when the backup ring 64 is mounted in the annular groove 2, the third seal ring 63 is mounted thereon, and a pair of seal rings 61 and 62 are further arranged on the backup ring 64, a third seal is formed. The inner peripheral surface 63b of the ring 63 is in contact with the outer peripheral surface 64a of the backup ring 64 and receives the bulging stress F.

Then, a pair of seal rings 61 and 62
Is slidably in contact with the angled sloped surface 63a of the third seal ring 63 via the sloped surfaces 61c and 62c, the bulging stress F is received from the backup ring 64 so that the pair of seals The rings 61 and 62 are not only expanded in diameter, but the seal ring 61 is subjected to the stress of moving to the direction D1 side, and the seal ring 62 is subjected to the same stress in the direction D2. Become.

As a result, the outer peripheral surface 6 of the seal ring 61 is
1a is pressed against the inner peripheral surface 3a of the cylinder 3, the end surface 61b is pressed against the side wall 21 of the annular groove 2, the outer peripheral surface 62a of the seal ring 62 is pressed against the inner peripheral surface 3a of the cylinder 3, and the end surface 62b.
Are pressed against the side walls 22 of the annular groove 2, and the upper and lower sides of the gap G formed between the displacer 1 and the cylinder 3 are formed by the pair of seal rings 61, 62, the third seal ring 63, and the backup ring 64. The seal member 6 is completely sealed.

Since the present invention is not limited to the above embodiments, various modifications can be made without departing from the spirit of the claims. For example, as shown in FIG. 4, all or part of the outer peripheral surface of the seal ring 51 is formed in an arc shape, or as shown in FIG. 5, the end surface 61b of the seal ring 61 and the end surface 62b of the seal ring 62 are formed. It is also possible to form the whole or a part in an arc shape or the like.

[0034]

As described above, the sealing member of the present invention has a good sealing performance in spite of its simple structure and easy mounting.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment.

FIG. 2 is an explanatory diagram of a second embodiment.

FIG. 3 is an explanatory diagram of a third embodiment.

FIG. 4 is an explanatory view of a modified implementation of the second embodiment.

FIG. 5 is an explanatory view of a modified implementation of the third embodiment.

FIG. 6 is an explanatory view of a conventional seal member.

FIG. 7 is an explanatory diagram of a main part of a Gifode-McMahon type refrigerator using a conventional seal member.

FIG. 8 is an explanatory view taken along line AA in FIG. 5 and seen from the arrow direction.

FIG. 9 is an explanatory view of another conventional seal member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Displacer 2 Annular groove 21/22 Side wall 3 Cylinder 3a Inner peripheral surface 4 Seal member 41 Seal ring 41a Outer peripheral surface 41b Protrusion 41g Non-continuous portion 42 Backup ring 42g Non-continuous portion 5 Seal member 51/52 Seal ring 51a / 51c / 52a 52c End surface 51b Outer peripheral surface 52b Inner peripheral surface 53 Backup ring 53a Outer peripheral surface 6 Seal member 61/62 Seal ring 61a / 62a Outer peripheral surface 61b / 62b End surface 61c / 62c Inclined surface 63 (Third) seal ring 63a Inclined surface 63b Inner peripheral surface 64 Backup ring 64a Outer peripheral surface 7 Seal member 71 Seal ring 71a Outer peripheral surface 71g Discontinuous portion 72 Backup ring 72g Discontinuous portion 8 Seal member 81 Seal ring 82/83 Spring ring D1 / D2 direction F Expansion stress G Gap

Claims (3)

[Claims] 1. A seal ring that is mounted by providing an annular groove formed on the outer peripheral surface of a piston with a discontinuous joint-shaped discontinuous portion, and a bulging stress applied to the seal ring inside the seal ring. And a backup ring for providing a seal ring, wherein the seal ring is formed with a projection on the inner peripheral surface of a portion separated from the discontinuous joint-like discontinuous portion, and the backup ring is A seal member, which is formed in a C shape by one discontinuous portion that allows the protrusion of the seal ring to be fitted therein. 2. A pair of seal rings, which are arranged in parallel with each other with one end surfaces in contact with an annular groove formed on the outer peripheral surface of the piston,
A seal member comprising a backup ring mounted inside the pair of seal rings to apply a bulging stress to the seal rings, wherein the contact side end faces of the pair of seal rings are slidable surfaces. A seal member characterized by being formed in. 3. A pair of seal rings, which are arranged side by side in a non-contact state in an annular groove formed on the outer peripheral surface of the piston, and a third seal ring which is mounted inside by contacting the pair of seal rings. And a backup ring attached to the inside of the third seal ring for applying a diametrical stress to the seal ring, wherein each of the pair of seal rings is attached to an inner peripheral surface of the cylinder. An outer peripheral surface in contact, an end surface in contact with the opposing side wall defining the axial width of the annular groove, and an inclined inner surface,
A seal member, wherein the third seal ring is formed with a mountain-shaped inclined surface slidably in contact with each of the inclined surfaces of the pair of seal rings.