Allison Transmission, Inc.

Elizabeth P Dick

James Allen Raszkowski

William S Reed

Bryan H Hagelskamp

Doug S Burchett

John Murdock

Embodiments of the present disclosure provide a transmission spool valve/valve body arrangement facilitating the manufacturing of the valve body chambers accommodating the spool valves. Specifically, embodiments of the present disclosure provides a valve body having a common datum from which machining for each valve cavity formed through a particular face of a valve body can be referenced. In particular embodiments of the disclosure, a spring biases a solenoid assembly for each valve against a datum (common or otherwise). In more particular embodiments of the disclosure, the spring biases the solenoid assembly in a direction opposite to the direction of actuation of the spool valve upon actuation of the solenoid assembly. The spring bias positively displaces the solenoid assembly to the datum for precision location of the solenoid relative to the various hydraulic ports of the respective valve chamber. A variety of spring clip arrangements are provided to index the solenoid to the valve body.

Linear force solenoid valve body mounting

A multi-speed planetary transmission is operable in at least nine forward speed ratios, at least one reverse speed ratio, and at least one neutral speed ratio. A hydraulic control system for the transmission includes a hydraulic default control system and is operable to a default configuration when a default condition occurs during operation of the transmission. The hydraulic control system defaults to a forward default gear ratio during operation of the transmission in a first forward speed ratio and defaults to a default neutral speed ratio during operation of the transmission in a reverse speed ratio when a default condition occurs. The default condition may be a transmission control module ('TCM') power failure.

Power off hydraulic default strategy

A clutch assembly configured to engage and disengage a first shaft from a second shaft includes a controlled and predetermined cooling flow to cool the clutch assembly. The clutch assembly includes a clutch housing, friction plates, and reaction plates optimized to manage fluid flow through the clutch assembly. A plurality of fluid flow outlets is provided to move fluid from an interior of a clutch housing of the clutch assembly to an exterior of the clutch housing.

Growing community of inventors

Mooresville, IN, United States of America

Elizabeth P Dick