Patent Number: 6,305,521

Title: Hydraulically actuated piston with an air bleed

Abstract: A torque transmitting mechanism has a hydraulically actuated piston that is slidably disposed in a cavity. An apply chamber, formed by the piston and cavity, is filled with hydraulic fluid when the torque transmitting mechanism is to be engaged. One or more gas permeable--liquid impermeable mats are secured in a passage between the chamber and a non-liquid area in a transmission. During initial engagement of the torque transmitting mechanism, any entrapped air is forced out of the chamber through the mat while the leakage of liquid is inhibited. In a rotating torque transmitting mechanism (clutch), the mats are installed near the innermost periphery of the chamber. In a stationary torque transmitting mechanism (brake) the mats are installed near the top outermost periphery of the chamber.

Inventors: Hall, III; Arthur (Cicero, IN), Witte; Larry L. (Danville, IN)

Assignee: General Motors Corporation

International Classification: B60T 17/18 (20060101); B60T 17/22 (20060101); F15B 21/00 (20060101); F16D 25/00 (20060101); F16D 65/14 (20060101); F15B 21/04 (20060101); F16D 48/00 (20060101); F16D 25/12 (20060101); F16D 48/02 (20060101); F15B 021/04 ()

Expiration Date: 10/23/2018