Self replenishing accumulator

Patent metadata

Field	Value
Publication number	US-9541099-B2
Application number	US-201414219064-A
Country	US
Kind code	B2
Filing date	Mar 19, 2014
Priority date	Apr 17, 2013
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

An accumulator includes a cylinder for containing a working fluid and a first volume of pressurized gas, the gas and fluid being separated by a displaceable piston and a first seal contacting the piston and the cylinder, a reservoir carried on the piston for containing a second volume of pressurized gas, and a device that permits gas flow from the second volume into the first volume.

First claim

The invention claimed is:

1. An accumulator comprising:
a cylinder containing a working fluid and first volume of pressurized gas separated by a displaceable piston, and a first seal between the piston and the cylinder;
a reservoir carried on the piston containing a second volume of pressurized gas, and a sealed opening between the second volume and working fluid for pressurizing the second volume;
a device that permits gas flow from the second volume into the first volume.

2. The accumulator of claim 1 , wherein the device comprises an upper cell fixed to the piston and extending normal to a direction of displacement of the piston, and an elastomeric second seal extending through a hole through the upper cell carried on the piston and permeable to gas flow from the second volume into the first volume via elastomeric flexing of the second seal.

3. The accumulator of claim 2 , wherein a cross sectional area of the second seal is scaled such that gas flow from the second volume into the first volume is slightly slower than gas flow out of the first volume into the working fluid.

4. The accumulator of claim 2 , wherein a cross sectional area of the second seal is scaled to a pressure differential between the first and second volumes.

5. The accumulator of claim 2 , wherein permeability of a material used for the second seal is scaled such that gas flow from the second volume into the first volume is slightly slower than gas flow out of the first volume.

6. The accumulator of claim 2 , wherein permeability of a material used for the second seal is scaled to a pressure differential between the first and second volumes.

7. The accumulator of claim 1 , wherein the device comprises an upper cell fixed to the piston and extending normal to a direction of displacement of the piston, and a valve extending through a hole through the upper cell that moves axially relative to the upper cell to open communication between the first and second volumes when pressure in the first volume exceeds pressure in the second volume, and closes communication between the first and second volumes when pressure in the second volume exceeds pressure in the first volume.

8. The accumulator of claim 7 , further comprising a second valve that relieves pressure of the working fluid when pressure of the working fluid exceeds a reference pressure.

9. The accumulator of claim 1 wherein the working fluid is an automatic transmission fluid.

10. The accumulator of claim 1 wherein the piston is housed within the cylinder.

11. The accumulator of claim 2 wherein the second seal is on an axially opposite end of the piston from the sealed opening.

12. The accumulator of claim 1 wherein the device comprises a valve slidable axially relative to the piston to selectively seal and open communication between the first and second volumes.

13. The accumulator of claim 1 wherein the device comprises a valve slidable axially relative to the piston to open communication between the first and second volumes when the piston compresses the gas such that the valve contacts an axial end wall of the cylinder.

14. An accumulator comprising:
a cylinder containing a working fluid and first volume of pressurized gas separated by a displaceable piston, and a first seal between the piston and the cylinder;
a reservoir carried on the piston containing a second volume of pressurized gas;
an upper cell fixed to the piston separating the first and second volumes, having an axially extending hole;
a device extending through the hole, selectively permitting gas flow therethrough, wherein the device comprises a valve slidable axially relative to the piston to selectively seal and open communication between the first and second volumes.

15. The accumulator of claim 14 wherein the piston includes a sealed opening between the second volume and working fluid for pressurizing the second volume.

16. The accumulator of claim 15 wherein the device is an elastomeric second seal, which is on an axially opposite end of the piston from the sealed opening.

17. The accumulator of claim 14 wherein the device comprises an upper cell fixed to the piston and extending normal to a direction of displacement of the piston, and an elastomeric second seal extending through a hole through the upper cell carried on the piston and permeable to gas flow from the second volume into the first volume via elastomeric flexing of the second seal.

18. The accumulator of claim 14 wherein the device comprises a valve slidable axially relative to the piston to open communication between the first and second volumes when the piston compresses the gas such that the valve contacts an axial end wall of the cylinder.

Assignees

• Ford Global Tech Llc

Inventors

• Pekarsky Lev
• Burkhart Robert O
• Davis Mark

Classifications

• Y10T137/0318

  Processes · CPC title

• F15B1/08

  using a gas cushion; Gas charging devices; Indicators or floats therefor · CPC title

• F15B2201/31

  having rigid separating means, e.g. pistons · CPC title

• F15B2201/205

  using gas · CPC title

• F15B1/24 Primary

  with rigid separating means, e.g. pistons · CPC title