Dual pre-load cylindrical seal

Patent metadata

Field	Value
Publication number	US-9752679-B2
Application number	US-201514673937-A
Country	US
Kind code	B2
Filing date	Mar 31, 2015
Priority date	Mar 31, 2015
Publication date	Sep 5, 2017
Grant date	Sep 5, 2017

Abstract

A cylindrical seal apparatus according to one embodiment includes a split spring ring and a split seal ring supported in a groove for example defined in a piston. The split spring ring in a tensioning condition presses against a tapered annular inner surface of the split seal ring to create a radial pre-load and an axial pre-load to the slit seal ring to establish a primary sealing contact between the seal ring and a cylinder, and a second sealing condition between the seal ring and a lower-pressure side of the groove, before the working fluid pressure is built up.

First claim

The invention claimed is:

1. A sealed assembly comprising:
a first cylindrical component telescopically adjacent a second cylindrical component, one of the first and second cylindrical components defining a chamber in which the other of the first and second cylindrical components is axially moveable;
a working fluid received in the chamber, the working fluid for creating a working fluid pressure on the other of the first and second cylindrical components to axially move the other of the first and second cylindrical component;
a split spring ring having two ends;
a split seal ring having two ends, the split seal ring defining substantially annular first and second radial surfaces facing away from each other, a substantially cylindrical surface extending axially between the first and second radial surfaces, and a tapered annular surface extending between the first and second radial surfaces at an oblique angle with respect to a central axis of the split seal ring; and
wherein the split spring ring and the split seal ring are supported in a groove defined in the first cylindrical component, the groove being open toward a cylindrical surface of the second cylindrical component, the groove defining opposite side walls, the split spring ring slidingly received against the tapered annular surface of the split seal ring, the split spring ring being pre-loaded under a tensioning condition to create a radial pre-load and an axial pre-load on the split seal ring by pressing against the tapered annular surface of the split seal ring, the substantially cylindrical surface of the split seal ring being pressed radially against and in a sealing contact with the cylindrical surface of the second component by the radial pre-load, and the first radial surface of the split seal ring being pressed axially against and in a sealing contact with one of the side walls of the groove by the axial pre-load, the second radial surface and the tapered annular surface of the split seal ring being in fluid communication with the chamber so that upon creation of the working fluid pressure in the chamber, the working fluid pressure acts on the tapered annular surface in a direction of the axial pre-load and the working fluid pressure takes over from the axial pre-load as a predominant sealing force on the split seal ring.

2. The sealed assembly as defined in claim 1 wherein the substantially cylindrical surface of the split seal ring defines an outer diameter surface of the split seal ring and wherein the tapered annular surface of the split seal ring defines an inner diameter surface of the split seal ring.

3. The sealed assembly as defined in claim 2 wherein the first component comprises a piston and the second component comprises a cylinder defining the chamber in which the piston is moveably received.

4. The sealed assembly as defined in claim 1 wherein the substantially cylindrical surface of the split seal ring defines an inner diameter surface of the split seal ring and wherein the tapered annular surface of the split seal ring defines an outer diameter surface of the split seal ring.

5. The sealed assembly as defined in claim 4 wherein the first component comprises a cylinder defining the chamber and having a bore extending through an end wall of the cylinder, said groove being defined in the bore and wherein the second component comprises a piston rod which moveably extends through the bore of the cylinder.

6. The sealed assembly as defined in claim 1 wherein the groove is configured to limit the split spring ring and split seal ring within the groove such that the direction of the axial pre load created on the split seal ring is determined by a cross sectional configuration of the groove.

7. The sealed assembly as defined in claim 1 wherein the groove comprises a step on a bottom of the groove at one of the first and second side walls, resulting in a first groove depth being different from a second groove depth.

8. The sealed assembly as defined in claim 1 wherein the groove comprises a surface extending between the opposite side walls at an oblique angle with respect to the central axis of the split seal ring.

9. The sealed assembly as defined in claim 1 wherein the groove comprises a surface extending between the opposite side walls, the surface free of contact with the split spring ring.

10. The sealed assembly as defined in claim 1 wherein the two ends of the split seal ring overlap each other, defining overlapping surfaces extending at an oblique angle with respect to the central axis of the split seal ring.

11. The sealed assembly as defined in claim 1 wherein the angle at which the tapered annular surface extends between the first and second radial surfaces with respect to the central axis of the split seal ring, is between 15 and 45 degrees.

12. A sealed assembly comprising:
a cylinder and piston movable in a chamber of said cylinder;
a working fluid received in the chamber, the working fluid for creating a working fluid pressure on the cylinder to axially move the cylinder;
a split spring ring having two ends;
a split seal ring having two ends, the split seal ring defining substantially annular first and second radial surfaces facing away from each other, an outer diameter surface extending axially between the first and second radial surfaces, and an inner diameter surface extending between the first and second radial surfaces at an oblique angle with respect to a central axis of the split seal ring; and
wherein the split spring ring and the split seal ring are supported between opposite side walls of a groove defined in the piston, the split spring ring slidingly received against the inner diameter surface of the split seal ring, the groove being open toward an inner surface of the cylinder, the split spring ring being pre-loaded in a tensioning condition to create a radial pre-load and an axial pre-load on the split seal ring by pressing against the inner diameter surface of the split seal ring, the outer diameter surface of the split seal ring being pressed radially outwardly against and in a sealing contact with the inner surface of the cylinder by the radial pre-load, and the first radial surface of the split seal ring being pressed axially against and in a sealing contact with one of the side walls of the groove by the axial pre-load, the second radial surface and the inner diameter annular surface of the split seal ring being in fluid communication with the chamber so that upon creation of the working fluid pressure in the chamber, the working fluid pressure acts on the inner diameter annular surface in a direction of the axial pre-load and the working fluid pressure takes over from the axial pre-load as a predominant sealing force on the split seal ring.

13. The sealed assembly as defined in claim 12 where the split spring ring comprises a tapered annular surface in full contact with the inner diameter surface of the split seal ring.

14. The sealed assembly as defined in claim 12 wherein the split spring ring is free of contact with a surface of the groove extending between the opposite side walls.

15. The sealed assembly as defined in claim 12 wherein the groove is configured to have a varying depth in a cross section of the groove, resulting in guided positioning of the split spring ring and split seal ring to create said axial pre load in a direction of a pressure differential of a working fluid cross the piston during piston operation in the cylinder.

16. The sealed assembly as defined in claim 12 wherein the two ends of the split seal ring comprise a pair of overlapping surfaces extending at an

Assignees

• Pratt & Whitney Canada

Inventors

• Urac Tibor
• Chow Bernard

Classifications

• F16J15/56

  Other sealings for reciprocating rods · CPC title

• F16J9/06 Primary

  using separate springs {or elastic elements} expanding the rings; Springs therefor {; Expansion by wedging} · CPC title

• F16J9/12

  Details · CPC title

• F16J15/3208

  provided with tension elements, e.g. elastic rings · CPC title