JPS5881271A - Mechanical seal assembled body - 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 Mechanical seal assemblies for sealing a rotating shaft to a housing having a shaft opening through which the shaft extends are known in the art. When subjected to high pressures, particularly when subjected to variable high pressures, some prior art mechanical cooling systems experienced excessive leakage and uneven performance.

According to the invention, a mechanical seal for sealing a rotary shaft in a housing having a shaft opening through which the shaft extends is connected to the shaft for rotation therewith and for limited axial movement relative to the shaft. and a rotatable sealing ring means connected to the housing and a fixed sealing ring means connected to the housing. The rotating and stationary sealing ring means have opposed generally radial lapped sealing surfaces and means are provided for bringing the sealing rings closer together. The rotatable sealing ring is comprised of a pair of integral helical ring sections each having a generally stepped configuration and each having the same axial length or dimension. One ring section has an inner diameter and an outer diameter that are larger than the inner and outer diameters of the other ring section, respectively. The respective ratios of the inner and outer diameters of the paired ring portions are selected to bias the sealing surface of the rotatable sealing ring means to the desired degree. If the ring parts contract approximately the same amount, the sealing surface remains flat; if the ring part with the larger inner and outer diameters contracts more than the other ring parts, the sealing surface becomes convex; if the opposite relationship is chosen, the sealing surface remains flat; , the sealing surface becomes concave.

Embodiments of the invention will be described in detail below with reference to the accompanying drawings.

1 is a mechanical seal assembly 10 that includes a multi-part housing 12 through which a shaft 14 extends. A shaft sleeve 16 loosely surrounds the shaft 14 and is keyed or otherwise fastened to the shaft for rotation therewith (not shown). Mechanical seal assembly 10 further includes rotatable sealing ring means 18 and stationary sealing ring means 20, including ring means 18.
20 each have lapped sealing surfaces 22, 24 facing each other. Sealing ring means 20
is provided by a backup ring 26 that is keyed to and sealed to the housing 12.

The rotatable sealing ring means 20 is keyed into the sealing ring holder 28 by a key 29, the key 29 engaging a U-shaped cup 34 which fits within the holder 28 and abuts the rear of the sealing ring means 18. It is keyed to a U-shaped cup follower 30 having a snout 82.

The U-shaped cup follower 80 is drivingly connected to the annular spring holder 36 by a drive pin 88 .
has a plurality of longitudinally extending spring pockets 40, each pocket containing a spring 42 for pressing the U-shaped cup follower against the U-shaped cup 34 and the sealing ring means 18 against the other sealing ring means 20. It accommodates. As shown, one drive pin 38 has a U-shaped cup follower 8
0 slot 44 is inserted to allow longitudinal movement of the follower and rotation with the shaft and shaft sleeve. The arrangement of parts described above is generally conventional and is shown in U.S. Pat. No. 8,628,799, issued Dec. 21, 1971. O-IJ songs are conventionally used when necessary or desirable.

According to the invention, the rotatable sealing ring means 18 consists of two parts, each designated A%B, although, unlike in the case of the U.S. patent, they are step-shaped and of monolithic construction. Part A,
B have the same axial length or dimension, i.e. have the same length measured in the direction of axis 14.

By making the longitudinal section of the ring parts A, H such that they contract to the same extent under hydraulic loading or pressure, the flatness of the end face 22 remains unchanged.

However, if it is desired that the end face 22 becomes concave under pressure, the cross-section of section A should be dimensioned such that it contracts more than section B. On the contrary, if the end face 22 is made convex under pressure, part B should contract more than part A. It can be calculated using the equation to measure the compressive circumferential stress, namely: In the above equation, U = Contraction α = Inner radius b = Outer radius p = Positive pressure = Modulus of elasticity V = Poisson's ratio. Sealing ring means 1 showing radius of one part
8 is the indication. Approximately 44 to 9/cat” (625psi
) and has a modulus of elasticity of 5.9 x 10' and a Poisson's ratio of 0.236. The contraction of is shown in the chart below.

Case 1 A 8.625 7. f385
2.859B 8.168 7.088 2
．． 885 Case 2 A 8.500 7.885 3
．． 116B B, 125 7,088 2.
915 Case 8 1 8.750? ,885 2
．． 649B B, 125 7.088 g
, 915 With the inner and outer diameters shown in case 1, the shrinkage is approximately the same and therefore the sealing surface 22 remains approximately flat. In case 2, the ring portion A has a smaller amount of contraction than the ring portion, and therefore the sealing surface 22 has a convex shape.

In case 8, ring part B has a greater amount of shrinkage than ring part A, so that the sealing surface 22 is concave.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a mechanical seal assembly according to the present invention, and FIG. 2 is a perspective view of rotatable sealing ring means used in the first mechanical seal assembly. 12: Housing 14: Shaft 18: Rotatable sealing ring means 20: Fixed sealing ring means 22. 24: Sealing surface 42 = Biasing means % Applicant
Bork Warner Corporation (4 others)

Claims (4)

[Claims] (1) A mechanical seal assembly that seals a rotating shaft (14) to a housing (12) having a sleeve opening through which the shaft (14) extends, and that rotates therewith and is confined relative to the shaft. rotatable sealing ring means (18) connected for axial movement over a distance; fixed sealing ring means (20) connected to the housing; and means for urging the sealing ring means toward each other. ,
The rotatable and stationary sealing rings have mutually opposed generally radial sealing surfaces (22, 24), and the rotatable sealing ring means is stepped and includes a pair of integral ring portions (22, 24).
4, B), each ring part has the same axial dimension, one ring part has an inner and outer diameter each larger than the inner and outer diameter of the other ring part, and the diameter of the paired ring parts is rotatable A mechanical seal assembly (10) characterized in that the sealing surface of the sealing ring is selected to deflect to a desired degree. (2) A patent claim characterized in that the contraction of each ring portion is determined by the following equation, where U = amount of contraction α = inner radius b = outer radius p = positive pressure = elastic modulus V: Boarnon ratio range lK
Mechanical seal assembly as described. (3) The mechanical seal according to claim 2, wherein one ring portion has a lapped sealing surface, and the contraction of the ring portion having the lapped sealing surface is approximately the same as the contraction of the other ring portion. assembly. (4) Claim 2 in which one of the ring portions has a lapped sealing surface, and the contraction of the ring portion having the lapped sealing surface is greater than the contraction of the other ring portion.
Mechanical seal assembly as described in. 6) The mechanical seal assembly according to claim 2, wherein one ring portion has a lapped sealing surface, and the contraction of the ring portion having the lapped sealing surface is smaller than the contraction of the other ring portion. body.