Piston for automatic transmission
AssigneeNok Corporation
InventorKiichiro Goto
Life of this patent
Estimating the term…
Abstract
To prevent effects of small amplitude oscillations caused by pressure fluctuation, eccentric attachment of a cancel plate and biased load application of a return spring, and to achieve a long service life of the inner peripheral seal portion, a BPS (1) with a piston member (20) moving in an axial direction inside a cylinder (10) and defining a compression chamber (M) together with the cylinder (10) and a cancel plate (30) opposing to a bottom portion (11) of the cylinder (10) beyond the piston member (20) is provided with an inner peripheral seal portion (50) with a seal lip (52) slidably contacting an inner peripheral tube portion (13) of the cylinder (10) and a fitting portion (53) fitted to the inner peripheral tube portion (13) in an inner peripheral end portion (35) of the cancel plate (30).
Claims2
A piston for an automatic transmission comprising:
- a piston member moving in an axial direction in an inner portion of a closed-end cylindrical cylinder and defining a compression chamber together with said cylinder;
- a cancel plate opposing a bottom portion of said cylinder beyond said piston member and defining a balance oil chamber together with said piston member and said cylinder;
- a return spring adapted to push back said piston member which is pushed down by said compression chamber being pressurized;
- and
- an inner peripheral seal portion arranged on an inner peripheral end portion of said cancel plate and formed by a rubber-like elastic material, said inner peripheral seal portion including a seal lip which is in close contact with an inner peripheral tube portion of said cylinder, and a fitting portion fitted to said inner peripheral tube portion of said cylinder.
Dependencies are inferred from the claim text.