One-way pressure activated piston seal

Abstract

A solenoid actuated valve (10) holds pressure and volume of an accumulator with low leakage and provides low actuation drag during a release stroke for dumping fluid contents of the accumulator at very low current draw. Two elongate valve members (10a, 10b) are assembled to be movable axially relative to one another with a gland or groove (10c) formed in one of the two valve members (10a). An o-ring (12) located within the groove (10c) is in a non-contacting relationship to the other valve member (10b) when in a non-energized state. An energizer ring (14) located within the groove (10c) can reciprocate axially with respect to the o-ring (12). The energizer ring (14) moves axially toward the o-ring (12) in response to fluid pressure against a surface (14a) of the energizer ring (14) opposite from the o-ring (12) to axially compresses the o-ring (12), causing the o-ring (12) to expand radially outwardly into sealing contact with the other valve member (10b).

Claims

1. A method for holding pressure and volume of an accumulator with low leakage and for providing low actuation drag during a release stroke of a solenoid actuated valve (10) for dumping fluid contents of the accumulator at very low current draw comprising: providing a groove (10c) in one of two elongate valve members (10a, 10b) movable axially with respect to one another; positioning an o-ring (12) in the groove (10c); maintaining the o-ring (12) in a non-contacting relationship with respect to the other of the two elongate valve members (10b) when in a non-energized state; and assembling an energizer ring (14) within the groove (10c) for axially reciprocal movement with respect to the o-ring (12), where the energizer ring (14) is axially movable toward the o-ring (12) in response to fluid pressure against a surface (14a) opposite from the o-ring (12) and the o-ring (12) being compressible by the energizer ring (14) thereby causing radial expansion of the o-ring (12) into sealing contact with the other of the two elongate valve members (10b) when in an energized state thereby sealing the solenoid actuated valve (10) in response to fluid pressure for holding pressure and volume of the accumulator with low leakage while the two elongate valve members (10a, 10b) are stationary with respect to one another, where the o-ring is releasable from the energized state between the two elongate valve members (10a, 10b) into the non-energized state in response to initial movement of a release stroke of the solenoid actuated valve (10) thereby providing low actuation drag during relative movement between the two elongate valve members (10a, 10b) for dumping fluid contents of the accumulator at very low current draw.

2. The method of claim 1 further comprising: providing the energizer ring (14) with a rectangular cross section.

3. The method of claim 1 further comprising: providing the energizer ring (14) with an L-shaped cross section (14b).

4. The method of claim 1 further comprising: providing the energizer ring (14) with an L-shaped cross section (14b) having an angled o-ring engaging surface (14c).

5. A one-way pressure activated piston seal comprising: two elongate members (10a, 10b) movable axially relative to one another with a groove (10c) formed in one of the two elongate members (10a); an o-ring (12) located within the groove (10c) formed in the one of the two elongate members (10a), while the o-ring (12) is maintained in a non-contacting relationship with respect to the other of the two elongate members (10b) when in a non-energized state; and an energizer ring (14) located within the groove (10c) for axially reciprocal movement with respect to the o-ring (12), where the energizer ring (14) is axially movable toward the o-ring (12) in response to fluid pressure against a surface (14a) opposite from the o-ring (12) and the o-ring (12) being compressible by the energizer ring (14) to expand the o-ring (12) radially into sealing contact with the other of the two elongate members (10b) when in an energized state while the two elongate members (10a, 10b) are stationary with respect to one another, where the o-ring is releasable from the energized state between the two elongate members (10a, 10b) into the non-energized state in response to initial movement between the two elongate members (10a, 10b) minimizing drag during relative movement between the two elongate members (10a, 10b).

6. The seal of claim 5, wherein the energizer ring (14) has a rectangular cross section.

7. The seal of claim 5, wherein the energizer ring (14) has an L-shaped cross section (14b).

8. The seal of claim 5, wherein the energizer ring (14) has an L-shaped cross section (14b) with an angled o-ring engaging surface (14c).

9. A solenoid actuated valve (10) for holding pressure and volume of an accumulator with low leakage and for providing low actuation drag during a release stroke of the solenoid actuated valve (10) for dumping fluid contents of the accumulator at very low current draw comprising: two elongate valve members (10a, 10b) movable axially relative to one another with a groove (10c) formed in one of the two elongate valve members (10a); an o-ring (12) located within the groove (10c) formed in the one of the two elongate valve members (10a), where the o-ring (12) is maintained in a non-contacting relationship with respect to the other of the two elongate valve members (10b) when in a non-energized state; and an energizer ring (14) located within the groove (10c) for axial movement with respect to the o-ring (12), where the energizer ring (14) is axially movable toward the o-ring (12) in response to fluid pressure against a surface (14a) opposite from the o-ring (12) and the o-ring (12) being compressible by the energizer ring (14) causing the o-ring (12) to expand radially into sealing contact with the other of the two elongate valve members (10b) when in an energized state thereby sealing the solenoid actuated valve (10) in response to fluid pressure for holding pressure and volume of the accumulator with low leakage while the two elongate valve members (10a, 10b) are stationary with respect to one another, the o-ring being releasable from the energized state between the two elongate valve members (10a, 10b) into the non-energized state in response to initial movement of a release stroke of the solenoid actuated valve (10) thereby providing low actuation drag during relative movement between the two elongate valve members (10a, 10b) for dumping fluid contents of the accumulator at very low current draw.

10. The valve (10) of claim 9, wherein actuation of the solenoid actuated valve (10) unloads compressive pressure on the o-ring (12) allowing retraction from the radially expanded energized state to the non-contacting relationship with respect to the other of the two elongated valve members (10a, 10b) in the non-energized state.

11. The valve (10) of claim 9, wherein the energizer ring (14) has a rectangular cross section.

12. The valve (10) of claim 9, wherein the energizer ring (14) has an L-shaped cross section (14b).

13. The valve (10) of claim 9, wherein the energizer ring (14) has an L-shaped cross section (14b) with an angled o-ring engaging surface (14c).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:

(2) FIG. 1 illustrates a cross sectional view of a one-way pressure activated piston seal for a solenoid actuated valve having a solenoid armature (acting as a piston) with a gland on the outside diameter (OD) that accommodates an o-ring and an energizing ring, where without fluid pressure, the o-ring sits in the gland and is located clear of the piston bore;

(3) FIG. 2 illustrates a detailed cross sectional view of the o-ring and energizer ring of the one-way pressure activated piston seal for a solenoid actuated valve according to FIG. 1, where the o-ring and energizer ring are in a relaxed, non-energized state with the o-ring located clear of the piston bore;

(4) FIG. 3 illustrates a detailed cross sectional view of the o-ring and energizer ring of the one-way pressure activated piston seal for a solenoid actuated valve according to FIG. 1, where the o-ring and energizer ring are in an energized state with the o-ring compressed axially and expanded radially to seal the piston bore;

(5) FIG. 4 illustrates a detailed cross sectional view of the o-ring and energizer ring of the one-way pressure activated piston seal for a solenoid actuated valve according to FIG. 1, where the solenoid actuated valve moves in the direction of the arrow relieving compression of the o-ring and returning the o-ring and energizer ring to the relaxed, non-energized state of FIG. 2;

(6) FIGS. 5A-5B illustrate alternative cross sections for the energizer ring; and

(7) FIG. 6 illustrates a prior art solenoid valve having a standard o-ring energized PTFE piston seal ring, where the o-ring is used to load a PTFE-based seal ring against the inside diameter (ID) of a piston bore.

DETAILED DESCRIPTION

(8) Referring now to FIGS. 1-4, a solenoid actuated, fluid valve 10 is depicted for holding pressure and volume of an accumulator with low leakage and for providing low actuation drag during a release stroke of the solenoid actuated valve for dumping fluid contents of the accumulator at very low current draw. The fluid valve 10 can include two elongate valve members 10a, 10b capable of reciprocal movement axially relative to one another with a gland or groove 10c formed in one of two valve members 10a.

(9) As best seen in FIG. 2, an o-ring 12 is located within the groove 10c in non-contacting relationship to the other of the two valve members 10b when in a non-energized state. An energizer ring 14 is located within the gland or groove 10c for reciprocation axially with respect to the o-ring 12. The energizer ring 14 is illustrated as having a rectangular cross section, or square cross section, with a surface 14a on a side opposite from the o-ring 12. However, it should be recognized that the energizer ring 14 can have any desired cross section. By way of example and not limitation, the energizer ring 14 can have an L-shaped cross section 14b as illustrated in FIG. 5A, or L-shaped cross section with an angled o-ring engaging surface 14c as illustrated in FIG. 5B, or L-shaped cross section with a curved o-ring engaging surface, or a triangular shaped cross section, or any combination thereof. In any case, the energized ring 14 includes a surface 14a on a side opposite from the o-ring 12 allowing fluid pressure to act on surface 14a of the energizer ring 14 to drive the energizer ring 14 axially into compressive engagement with the o-ring.

(10) As best seen in FIG. 3, in response to fluid pressure, the energizer ring 14 moves axially toward the o-ring 12 against a surface 14a opposite from the o-ring 12. While in the fluid pressure energized state, the energizer ring 14 compresses the o-ring 12 causing the o-ring 12 to expand radially outwardly into sealing contact with the other of the two valve members 10b. The o-ring 12 is held in a radially outwardly expanded energized state by the energizer ring 14 in response to the fluid pressure acting on surface 14a.

(11) As best seen in FIG. 4, when the solenoid 18 energizes to initiate movement of the valve member 10a in the direction of arrow 16, the movement of the valve member 10a releases or unloads compressive pressure on the o-ring 12 by the energizer ring 14 allowing the o-ring 12 to retract or transition from the radially expanded condition illustrated in FIG. 3 to return to the non-energized state illustrated in FIG. 2.

(12) The one-way pressure activated piston seal assembly 20 was developed to resolve a sealing challenge related to a low-leak, high-flow, two-way, on/off, solenoid operated, hydraulic fluid valve. The solenoid operated fluid valve 10 is used to close and hold a pressurized hydraulic accumulator and then release and dump the accumulator when requested. In order hold the pressure and volume of the accumulator, the solenoid operated fluid valve 10 has very demanding leakage requirements. Additionally, the solenoid operated fluid valve 10 needs to be able to stroke and dump the accumulator at very low current draw and therefore needs to have low actuation drag.

(13) Referring again to FIG. 1, the solenoid operated fluid valve 10 is illustrated with the solenoid armature 10a acting as a piston and with a gland 10c on the outside diameter (OD) that accommodates an o-ring 12 and an energizing ring 14. Without pressure, the o-ring 12 sits in the gland 10c and is clear of the piston bore 26 defined by the inside diameter (ID) of the valve body 10b. The energizing ring 14 is designed as a clearance fit to the bore 26 as well, so there is little to no seal drag. When there is a pressure differential (higher pressure on the energizing ring side), the energizer ring 14 compresses the o-ring 12 forcing the outside diameter (OD) of the o-ring 12 out and into contact with the piston ring 10b and seals the piston bore 26. When the solenoid 18 is commanded to actuate and dump the accumulator, the piston 10a moves up and unloads the o-ring 12 allowing the o-ring 12 to retract from the piston bore 26 and eliminate the drag.

(14) While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.