Allison Transmission, Inc.

Ionut Manta

Evan Meredith

Nicholas Walke

A system has been developed for engaging a clutch pack using a hydraulic piston. The system can be used with an automatic transmission or another part of the drivetrain of a vehicle. The system includes a piston, a clutch pack, and a housing that contains the piston and clutch pack. To engage and disengage the piston against the clutch pack, the system is configured to fill and empty a hydraulic chamber on a hydraulic side of the piston such that the hydraulic fluid moves the piston towards and away from the clutch pack. The piston includes one or more pads or standoffs that form flow gaps. The piston is further configured to position seals on the piston closer to the hydraulic side.

Hydraulic piston design

Transmissions, park systems for transmissions, and methods for transmissions are envisioned. A transmission includes an input shaft to receive torque from a drive unit, an output shaft to transmit torque to a load, and a park system to selectively brake the output shaft. The park system includes a park assembly, an electro-hydraulic valve assembly to deliver one or more fluid pressures, and an actuation linkage having a piston axially translatable along a longitudinal axis in response to the one or more fluid pressures delivered thereto from the electro-hydraulic valve assembly.

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Avon, IN, United States of America

Ionut Manta