JPS604672A - Assembly of seal - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventional single stage seals that provide a single barrier to fluid leakage are generally inadequate for operation over a wide pressure range. The f6 pressure seal, consisting of a single resilient ring, tends to protrude into the clearance between the piston and cylinder, allowing high pressure fluid to exit between the seal and the member with which they each engage. Sometimes. Protrusion of such seals can be prevented by using a relatively hard, inelastic ring as a seal, but the inelastic ring must be too tight to operate effectively under high pressure. It has to be fitted.

As a result, such rings are unsuitable for use at low pressures and cause excessive friction and wear.

As a solution to this problem, the present invention provides a two-stage seal assembly. This two-stage seal assembly has a low pressure (7 to 2 t
7-kf/cm”-10D ~3D Opsi)
7. A deformable elastic seal ring that operates effectively;
It is formed to fit with the high pressure (
35.2kf/crr? -500 psi) and a backing ring made of a slightly elastic material such as unfilled Teflon or filled Teflon®. The sealing ring engages the relatively reciprocating member facing it to establish a seal at low pressure. At higher pressures, the relatively more resilient seal ring is pulled away from the relative reciprocating member and forces the backing ring radially into tight sealing contact with the relative reciprocating member. In this manner, the seal assembly operates effectively at both low and high pressures without causing excessive friction and wear at low pressures.

The seal assembly of the present invention is to be installed between an inner member and an outer member that move relatively, and includes an annular seal ring made of a deformable tC elastic material and a backing ring that fits with the annular seal ring. It is usually installed in a circumferential groove provided in the circumferential direction of the inner member.

The seal ring has a radial side defining a high pressure side of the seal assembly and an outer circumferential surface defined by four articulated sections. The first part of the four connected parts is approximately semicircular, the second part is an inclined surface extending from the first part at an angle of 10° to 400 degrees with respect to the radius of the seal ring, and The third part is an axially extending flange.

The radial edges of this flange cooperate with the radial walls of the groove to define a generally triangular space.

The fourth portion is a curved surface forming an intersection between the second and third portions.

The backing ring is trapezoidal in cross section and is radially disposed relative to the third portion of the sealing ring. The sides of the backing ring are angled inwardly at an angle of 50' to 70' relative to its axis and cooperate with the second and fourth portions to define a triangular space. The apex of this triangle is located on the circumferential surface of the seal assembly.

Accordingly, it is an object of the present invention to provide a new seal assembly that operates equally effectively at high and low pressures.

Values and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

Referring to FIG. 2, the seal assembly 10 of the present invention is shown mounted within a circumferential groove 16 formed in the piston 14. The seal assembly 10 consists of a seal ring 11 and a backing ring 12. Seal ring 11 has a radial side surface 18 on the pressure side of the seal assembly. Side 18 is the surface exposed to the pressure applied to the piston. A flange 20 is formed adjacent to this side surface 1B and extending in the axial direction at right angles thereto. flange 20
serves to stabilize the seal ring 11. Side 1
8, the flange 20, and the wall of the groove 16.
is defined.

The outer peripheral surface of the seal ring 11 has four connected surfaces 22.
．． 24.46.30. surface 24
is connected to the surface 22 and extends from the surface 22 to the seal ring 11
It widens at an angle of 10° to 40° with respect to the radius of .

This preferred angle of inclination is 15°. Surface 24 is connected to a curved converging surface 46, the latter being connected to surface 30.

Surface 30 defines the outer circumferential surface of flange 26 of seal ring 11 extending axially from the non-pressure side of the seal assembly. Flange 26 is the flange 2 on the pressure side of the assembly.
Significantly larger than 0.

The axial thickness of the ring 11 of the seal assembly 10 is
Thus, on the non-pressure side of the assembly 10 a space 42 of rectangular cross-section is defined by the radial surface 48 of the flange 26 and the wall of the groove 16. The bottom corners of the groove 16 can be rounded.

Backing ring 12 is disposed radially outwardly of flange 26 on the non-pressure side of the assembly. The ring 12 is trapezoidal in cross-section, with both sides 52 . 34 not parallel to each other, one radial side 62 abutting the wall of the groove 16 . The other inclined side surface 34 is arranged at a radius of 20' to 40' of the ring 12.
is inclined inward at an angle of The preferred angle is 3 points. A space 56 of triangular cross-section is defined by the surface 24.46 of the sealing ring 11 and the slope 1111 ij+i s 4 of the backing ring 12.

The outer diameter of the seal ring 11 is larger than the outer diameter of the 15-piece ring 12, and the protrusion 44 of the seal ring 11 defined by the semicircular surface 22 projects beyond the outer chisel d surface of the backing ring 12. . The volume +21 of the real part 44 must be smaller than the volume 411 of the triangular space 36 and the rectangular space 42.

Insert the piston 14 into the cylinder and seal assembly 10
When the seal ring 11 is brought into contact with the cylinder wall 38, the seal ring 11 deforms into the shape shown in FIG.

As a result of the deformation of the sealing ring 11, its surface 24 bulges into the triangular space 36. The triangular space 36 contracts but maintains its triangular shape. The side surface 18 of the sealing ring bulges into the space 4o.

Approximately 35-2klF/ctrt” (5
When a high pressure of 0 Opsi) is applied, the seal ring 11 deforms into the shape shown in FIG. That is, sealing ring 11 bulges into spaces 36 and 49, and the deformation of this sealing ring forces backing ring 12 radially outward into sealing engagement with cylinder plume 38. In this case, the triangular space 56 is eliminated, but the air space 1B] 40 on the pressure side of the seal assembly is enlarged considerably. Space 42 becomes very small. When the pressure returns to a lower value, the seal assembly returns to the configuration shown in FIG.

Seal ring 11 should be formed from a material that is considerably more flexible than backing ring 12. The usable range of material hardness is about 60-90 durometer. A preferable material for the seal ring 11 is elastic rubber. On the other hand, the backing ring 12 is not hard like rock;
Instead, it should be made of an elastic, low-friction material. A particularly suitable material for the backing ring 12 is unfilled or filled polytrifluoroethylene, available under the trade name "Teflon".

FIG. 5 is a graph showing the emulsification of the friction force 6 of various seals with respect to fluid pressure. The frictional force is 1. It is expressed as the axial drag force (lb-,) of the seal against a 4t275rwn (1'in) diameter rond with a Brm5° finish. The numerical values in this graph are calculated using well-known calculation formulas. Curve A is for a standard rubber o-ring (size 626) and curve B
is related to the same O-ring, but assumes that as the fluid pressure (internal pressure in the cylinder) increases, the O-ring's contact with the prad gradually loosens, as in the seal targeted by the present invention. It is a curve. This curve is an assumed curve, and the fluid pressure is s o o pst
(3s, 2kg, /cn?), the frictional force becomes zero. Track 19C is a published fluid pressure versus friction force curve for a Champagne Teflon coated O-ring seal assembly. The curve is the sum of curves ilB and C and represents the curve for the seal of the present invention.

Although the seal assembly of the present invention is shown as being fitted into a groove in the piston 14, it may also be fitted into a groove in the cylinder wall 38.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of the seal assembly of the present invention, FIG. 2 is a sectional view of the seal assembly of the present invention installed in a circumferential groove of a piston, and FIGS. 5 and 4 are respective views of the seal assembly. FIG. 5 is a cross-sectional view showing conditions under different pressures. FIG. 5 is a graph showing the friction force of various seals against fluid pressure. 11: Seal ring 12: Backing ring 14: Piston 16: Circumferential groove 1: Radial side surface 20: Axial flange 22: Semicircular contact surface 24: Inclined surface 26: Axial flange 30: Axial surface 32 .34: Radial side surface 56: Triangular space t1J 58 Nijilinda wall 42: Rectangular space 44: Protrusion 46: Curved surface procedure oil stop '+'F (method) October 11, 1980 Erection bar'l Display of the incident by Kazuo Wakasugi
1981 Application No. 109467 (Invented) Name Relationship with the case of the person who amended the seal assembly 711th edition Applicant's attorney telephone number 273-6436 Column 1 specification of the originator/applicant of the application to be amended Scope of Shufaqi's derogatory terms and conditions - Detailed explanation of the invention, power of attorney and its translation, 1 copy each of drawings, 1 copy of the contents of the drawings as shown in the attached sheet (no changes to the content) )

Claims (1)

[Scope of Claims] 1) For use between two members, an inner member and an outer member, that move relatively, the inner member and the outer member having two radial directions. In a seal assembly retained within a circumferential groove defined by a wall, a deformable elastic material having a hardness of approximately 60 to 90 on a durometer hardness scale is used to provide a pressure seal. I! consists of an annular seal ring, and a backing ring made of a low-friction material with slight elasticity, which is designed to fit with the seal ring and constitute a high-pressure seal. has a first radial side face facing the pressure side of the seal 81'' and a second radial side ITl! facing the non-pressure side opposite the pressure side. a second radial side defined by a radial surface of an axially projecting flange of the seal ring, said radial surface cooperating with a radial wall of said circumferential groove; The outer circumferential surface 91 of the seal ring is defined by four connected parts, the first part being a semicircular surface, The second part is an inclined surface extending from the first part at an angle of 10° to 40° with respect to the radius of the seal ring;
a portion is an axial surface of the flange, a fourth portion is a curved surface forming an intersection of the second portion and the fifth portion;
The sealing ring has a radial thickness greater than the radial thickness of the backing ring in an unstressed state, and has a protrusion projecting beyond the radial edge of the backing ring; The protrusion is located at the semicircular first portion on the outer peripheral surface of the seal ring.
the backing ring is trapezoidal in cross-section and is located radially outwardly from said third portion of the seal ring, one side of the backing ring being defined by the ring's NI
a surface inclined inwardly from 50' to 10° with respect to m and having an apex at the outer periphery of the seal assembly in cooperation with said second and fourth portions of the seal ring; A seal assembly defining a triangular space, the protrusion of the seal ring having a volume smaller than the sum of the volumes of the rectangular space and the triangular space. 2) Said pressure side of the sealing ring is defined by two articulated parts, the first part of which is a radially extending part and the second part of said axis of the non-pressure side of the seal X11 solid. 2. A seal assembly according to claim 1, wherein the axial flange is substantially smaller than the axial flange. 3) One of the two members is a piston and the other is a cylinder wall, the piston is adapted to engage the cylinder wall under high pressure, and the circumferential groove is provided in the piston. and the sealing ring deforms in the direction of the applied pressure to substantially crush the rectangular space, completely crushing and eliminating the triangular space, thereby causing the backing ring to radially 2. A seal assembly as claimed in claim 1, adapted to be forced outwardly into sealing contact with said cylinder wall. 4) The seal assembly according to claim 1, wherein the seal ring is made of rubber and the backing ring is made of Teflon.