JPH04203678A - Sealing device - Google Patents

Abstract

PURPOSE:To prevent gouge phenomena in a heel part of a seal as well as to maintain a sealing function for a long period of time by installing a wedge ring, pressing the inner end of a backup ring with the seal, in an interval between a groove of the backup ring and the seal. CONSTITUTION:When high pressure acts on U-packing 13, a wedge ring 16 is pressed to a groove 17 of a backup ring 15, whereby a wall surface of this groove 17 is stuck close to the wedge ring 16, and the backup ring 15 is deformed to some extent, thus the outer diameter side is expanded. On the other hand, a part being opposed to a heel part 13a of the U-packing 13 at the inner diameter side is pressed toward the inner side with action of the wedge ring 16, and an inner circumferential end being unopposed to the heel part 13a is contracted toward the inner part. Therefore, even if high pressure acts on the U-packing 13, there is no clearance between a plunger 12 and the side being opposed to the U-packing 13 of backup ring 15 and, what is more, any gouge phenomenon will not happen in the heel part 13a of the U-packing 13. Consequently, the U-packing 13 is usable for years.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a sealing device used for sealing ultra-high pressure fluid such as several thousand atmospheres.

[Conventional technology]

Conventionally, there is a sealing device of this type as shown in FIG. 6 (Japanese Utility Model Publication No. 2-6859). In this sealing device, a U seal 3 is arranged in a seal groove 2 provided in a main body 1, and a backup ring 5 is arranged between the wall surface of the seal groove 2 and the end face of the U seal 3, so that the U seal 3 protrudes. We are trying to prevent this.

[Problem to be solved by the invention]

However, in the conventional sealing device described above, when high pressure is applied to the U-packet 3, the backup ring 5 deforms radially outward, making it impossible to prevent the heel portion of the U-packet 3 from protruding. There is a problem in that the heel portion peels off. This peeling phenomenon will be explained below with reference to FIGS. 7 to 11. FIG. 7 shows the state of the U-packet 3 and the backup ring 5 at low pressure, where the gap on the inner diameter side of the backup ring 5 is indicated by a, and the gap on the outer diameter side of the backup ring 5 is indicated by b. Furthermore, Fig. 8 shows the state of the U-packet 3 and the backup ring 5 at high pressure, where the gap on the inner diameter side of the backup ring 5 is a'', and the gap on the outer diameter side of the backup ring 5 is denoted by b''. As will be explained below, a<a', b>b'.
It shows the state of dimensional change when applying
When compressive force acts on the backup ring 5 in the axial direction,
Its inner diameter A, outer diameter B, and thickness C are the inner diameter A°, the outer diameter B°, and the thickness C', and when compressive force is applied to both the inner and outer diameters, the dimensions expand and the thickness becomes thinner. Therefore, as shown in Fig. 8, the gap a' on the inner diameter side of the backup ring 5 becomes larger when the pressure is high than the gap a on the inner diameter side when the pressure is low, and the gap b'' on the outer diameter side when the pressure is high is low. Therefore, as shown in FIGS. 10 and 11, which are enlarged views of the portion indicated by X in FIG. 8, the U-packet 3 peels off. Now, when high pressure is applied to the U packing ring 3 and compressive force is applied to the backup ring 5, the first
As shown in figure O, the U packing is pushed to the left as shown by the arrow, and the inner diameter of the backup ring 5 is pushed to the left as shown by the arrow RO.
The heel portion 8 of the U-pankin 3 is pushed into the gap on the inner diameter side of the backup ring 5 as shown in FIG. When the pressure acting on the U-packet goes from high to low, the inner diameter of the backup ring 5 contracts as shown by arrow RI, and the U-packet 3 moves to the right as shown by arrow R, as shown in FIG. try to move to. When the planer 4 reciprocates in such a state, the heel portion 8 of the U-pack 3 is gradually eaten away, a so-called peeling phenomenon occurs, and the heel portion 8 of the U-pack 3 is damaged. Therefore, an object of the present invention is to prevent the peeling phenomenon of the heel portion of the seal facing the inner diameter side of the backup ring,
It is an object of the present invention to provide a sealing device that can maintain its sealing function for a long period of time even when used under ultra-high pressure.

[Means to solve the problem]

To achieve the above object, the sealing device of the present invention includes a seal, a backup ring having an annular groove on the side opposite to the seal, and the buffer. The ring is disposed between a groove of the ring and the seal, and is pressed into the groove by the seal to press the inner end of the backup ring radially inward (a rust ring). Further, the radial cross section of the groove of the backup ring is approximately semicircular, and the radial cross section of the wedge ring is approximately semicircular, and the cross section of the groove in the radial direction is larger than the cross section of the groove. It is desirable that the wedge ring has a large cross-sectional area in the radial direction. It is also desirable that the wedge ring and the seal have an integral structure. Further, the bank-up ring and the wedge ring are formed of an elastic material. It is desirable to

[Operation] According to the above configuration, when high pressure is applied to the seal, the seal presses the wedge ring toward the groove of the backup ring. Therefore, the inner end of the backup ring is pressed radially inward by the wedge action of the wedge ring. The action of this wedge ring pressing the inner end of the backup ring radially inward causes Vanokwa. The inner end of the bling does not separate from, for example, the plunger (therefore, the seal does not dig into the inside of the backup ring, and the phenomenon of peeling of the seal is prevented. If the radial cross section of the wedge ring is approximately semicircular, stress concentration will not occur even if the wedge ring bites into the groove, and the backup ring and wedge ring will be It maintains its performance over a long period of time without being damaged.Also, if the cross-sectional area of the radial cross-section of the wedge ring is larger than the cross-sectional area of the groove in the radial direction, the wedge ring will Fill it completely and press the entire inner periphery of the inner end of the backup ring inward. Also, if the wedge ring and seal are integrated, it will be easier to handle. When the up ring and the wedge ring have elasticity, the wedge ring can be brought into close contact with the wall surface of the groove without any gaps, and the inner end of the backup ring can be uniformly pressed inward. [Example] ] This invention will be explained in detail below with reference to the illustrated embodiments. In Fig. 1, 10 is a cylinder, 11 is a ground metal, 12 is a plunger, 13 is a U-shaped ring, 15 is a backup ring, and 16 is a radius. It is a wedge ring with a substantially semicircular cross section in the direction. An annular groove 17 with a semicircular cross section is provided on the side of the upper J-vanoqua soft ring 15 facing the U packing 10. The circular arc sides of the wedge ring 16 are opposed to each other.The annular groove 17 of the backup ring 15
The radial cross-sectional area S1 of the wedge ring 16 is smaller than the radial cross-sectional area S2 of the wedge ring 16. The material of the back amp ring 15 is polysecure,
An elastic and self-lubricating engineering plastic such as ultra-high molecular weight polyethylene is used, and the wedge ring 16 is made of an elastomer having rubber elasticity such as polyurethane or fluororubber. Further, the U-packet 13 also uses the same elastomer having comb elasticity, such as polyurethane, which is the same as the wedge ring 16. According to the above configuration, when high pressure is applied to the U-packet 13, the groove 1 of the backup ring 15
7 presses the wedge ring 16, and the wedge ring 16 comes into close contact with the wall surface of the groove 17, and the pick-up ring 15 deforms as shown by the arrow in FIG. 2, expanding on the outer diameter side while expanding on the inner diameter side. The portion of the U pawl 13 facing the heel portion 13a is pressed inward by the action of the wedge ring 16, and the inner peripheral end portion not facing the heel portion 13a contracts inward. In the past, even if high pressure was applied to the U/<,7 pin 13, no gap would be created between the plunger 12 and the side of the back amplifier ring 15 facing the U/<, kin 13 in FIG. , U-bar, and the heel portion 13a of the kin 13 does not peel off. Therefore, U
The gasket 13 can be used for a long period of time. In the above embodiment, the radial cross section of the groove 17 of the bank knob ring 15 is approximately semicircular, and the radial cross section of the wedge ring 16 is approximately semicircular. Concentration does not occur (and performance can be maintained over a long period of time without damaging the backup ring 15 and the wedge ring 16. Also, the radius of the wedge ring 16 is smaller than the cross-sectional area S1 of the radial cross section of the groove 7). Since the cross-sectional area S2 in the direction is large, the wedge ring 16 completely fills the inside of the groove 17 and reliably presses the entire inner periphery of the inner end of the backup ring 15 inward. Since the backup ring 15 and the wedge ring have elasticity, the wedge ring 16 comes into close contact with the wall surface of the groove 17 without any gaps, and the inner end of the backup ring 15 can be uniformly pressed inward. FIG. 3 shows the above sealing device between the piston 21 and the cylinder 10.
It was used as a seal between the In this case as well, the backup ring 15 is connected to the piston 2 as shown by arrow F.
1 and the cylinder 10. FIG. 4 shows a modified example of the wedge ring and the backup ring, in which the backup ring 25 has an annular groove 26 with an approximately 1/4 circular cross section formed at its outer peripheral end, while the wedge ring 28 has a 1/4 circular cross section. The arcuate side faces the groove 26 of the backup ring 25. According to this configuration, the U patchkin 13 is the Kusahi song 28
When pressed, the hack-up ring 25 is pressed by the wedge ring 28 as shown by the arrow, and the side of the backup ring 25 facing the heel of the U-packet 13 is pressed toward the plunger I2 as shown by the arrow F. It will be done. Therefore, no gap is created between the backup ring 25 and the plunger 12, and the phenomenon of peeling of the U-packet 13 does not occur. In FIG. 5, the O-ring 30 is used as an integrated seal and wedge ring, and the O-ring 30 is attached to the backup ring 35 from the center to the bottom in the radial cross section.
A groove 36 having a curvature corresponding to the curvature of the groove 36 is formed. In this sealing device, when pressure is applied to the O-ring 30, the O-ring 30 comes into close contact with the hack knob ring 35, and the backup ring 3 located below the O-ring 30
Press the end of 5 inward and remove the hack up ring 3.
5 on the O-ring 30 side is brought into close contact with the plunger 12. Therefore, the phenomenon of peeling of the O-ring 30 does not occur. In this embodiment, since the seal and the bank up ring are integrated, assembly and handling are easy. In addition, also in the embodiment shown in FIG. 1, the seal and the backup ring may be integrated. Note that the wedge ring may be formed of a rigid material, and the backup ring may be formed of an elastic material.

【Effect of the invention】

The sealing device of the present invention is provided with an annular groove on the side opposite to the seal of the backup ring, and a wedge ring that presses the inner end of the backup ring radially inward between the annular groove and the seal. The inner end of the backup ring on the seal side can be pressed inward by the wedge ring, thus preventing the peeling phenomenon of the heel of the seal and allowing the seal to be used for a long time. . In addition, if the radial cross section of the groove of the backup ring is made approximately semicircular, and the radial cross section of the rust ring is made approximately semicircular, the stress concentration on the groove of the backup ring will be reduced. , also due to the wedge effect of the wedge ring. There is no risk of cracking in the ring. Also, the radial cross-sectional area of the wedge ring is larger than the radial cross-sectional area of the annular groove. Therefore, the inside of the annular groove can be completely filled with the wedge ring, and the inner end of the backup ring can be uniformly pressed inward.Furthermore, when the wedge ring and the 7-rule are integrated, In addition, when the hack-up ring and the wedge song are both made of elastic material, the backup ring and wedge ring come into close contact with each other due to elastic deformation. The inner end of the backup ring portion can be easily deformed and cracking can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sealing device according to an embodiment of the present invention, and FIG.
3 is a cross-sectional view showing an example in which the sealing device of the present invention is applied to a piston, FIG. 4 is a cross-sectional view of another embodiment of the sealing device of the present invention, and FIG. 6 is a sectional view of a conventional sealing device, FIGS. 7 and 8 are sectional views explaining the operation of the conventional sealing device, and FIG. FIG. 9 is a perspective view illustrating the state of deformation when compressive force is applied to the bank up ring, and FIGS. 10 and 11 are operation explanatory diagrams illustrating the peeling phenomenon. 10...Cylinder, 12...Plunger, 13...
・U Hanokin, 15...Backup ring, 16.2
8... Wedge ring, 17.26... Annular groove. Patent Applicant: Daikin Industries, Ltd. Agent: 1 person (Obaku Haka) Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Claims (4)

[Claims] (1) a seal; a backup ring having an annular groove on the side facing the seal; and a backup ring disposed between the groove of the backup ring and the seal and pressed by the seal toward the inside of the groove to support the backup ring. A sealing device comprising: a wedge ring that presses an inner end of the ring radially inward. (2) In the sealing device according to claim 1, the radial cross section of the groove of the backup ring is approximately semicircular, the radial cross section of the wedge ring is approximately semicircular, and the radial direction of the groove is approximately semicircular. A sealing device characterized in that the cross-sectional area of the radial cross-section of the wedge ring is larger than the cross-sectional area of the cross-section of the wedge ring. (3) In the sealing device according to claim 1 or 2,
A sealing device in which the wedge ring and the seal are integrally constructed. (4) The sealing device according to any one of claims 1 to 3, wherein the backup ring and the wedge ring are made of an elastic material.