Servo assembly for operating a brake band in an automatic transmission vehicle
AssigneeFord Global Tech., Inc.
InventorsJean Marie Miller, Robert Cary Haase, Felicia Paluzzi
Life of this patent
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Abstract
A servo assembly 22 for selectively engaging a brake band 14 in an automotive vehicle is disclosed. Servo assembly 22 includes a piston 26 at least partially encased in a housing 24 and a first and second supply 111, 132 of hydraulic fluid which selectively actuate the piston to engage the brake band.
Claims20
A servo assembly for engaging a brake band in a vehicle having an automatic transmission, said servo assembly comprising:
- a piston which selectively engages said brake band, said piston including a first portion and a second portion;
- a housing having an interior area, said housing at least partially surrounding said piston;
- an interior member which extends from said housing into said interior area of said housing thereby separating said interior area into a first area and a second area;
- a first pressurized supply which supplies a first amount of hydraulic fluid through a first opening in said housing to said first area wherein said first amount of fluid applies pressure to said first portion of said piston;
- a second pressurized supply which is separate from said first supply, which supplies a second amount of hydraulic fluid through a second opening in said housing to said second area wherein said second amount of fluid applies pressure to said second portion of said piston;
- and
- a spool which prevents said first amount of hydraulic fluid from entering said second portion of said piston.
A servo assembly for selectively actuating a piston which engages a brake band, said servo assembly comprising:
- a first pressurized supply of hydraulic fluid which supplies a first amount of hydraulic fluid to a first portion of said piston thereby applying a first pressure against said first portion;
- and
- a second pressurized supply of hydraulic fluid which supplies a second amount of hydraulic fluid to a second portion of said piston thereby applying a second pressure against said second portion;
- wherein said first portion only receives pressure from said first supply and said second portion only receives pressure from said second supply and said first pressure is controlled separately from said second pressure.
A method for actuating a piston within a servo assembly, said method comprising:
- providing a first pressurized supply of hydraulic fluid which selectively places a first pressure upon a first portion of said piston;
- providing a second pressurized supply of hydraulic fluid which selectively places a second pressure upon a second portion of said piston;
- and
- providing a spool which prevents said first supply of hydraulic fluid from entering said second portion of said piston and wherein said first portion only receives pressure from said first supply and said second portion only receives pressure from said second supply.
Dependencies are inferred from the claim text.