January 4, 2017

Means Launches Selectable One Way Clutch in GM 9 Speed Automatic Transmission


Selectable One Way Clutch

SAGINAW, Mich., Dec. 9, 2016 – The Means Selectable One Way Clutch (SOWC) has launched in the GM 9 Speed front wheel drive automatic transmission. News of this launch was announced on the GM website and stories have recently been published in Wards Auto, AutoBeat Daily and the Detroit Free Press.

This patented selectable one way clutch is a strut-based, mechanical clutching mechanism that helps improve fuel economy by way of reduced drag torque, lowered mass and improved packaging.

The 9T Hydra-Matic transmission started production in 2016 and is currently offered in the 2017 Chevy Malibu Premier. Next up to receive this transmission are the 2017 Chevy Cruze Diesel and the 2018 Equinox. As many as 10 GM vehicles will use this transmission by the end of 2017.

“We feel that our SOWC technology will be a significant contributor to helping OEM’s meet the 2025 emissions and mileage targets”, said Bill Shaw, President of Means. 

In addition to Automatic Transmissions, the SOWC is being considered for several hybrid transmissions under development, either as a shifting device for node control or as an electric motor disconnect device.

Its function in automatic transmissions is the coupling and decoupling of power flow nodes to achieve gear ratio change. Actuation can be accomplished hydraulically or electrically. 

The first applications in Automatic Transmissions are using the SOWC to replace the Low/Reverse friction clutch and one-way-clutch combination, typically yielding a 50% reduction in drag torque, up to 1.5 kg reduction in mass and 5mm to 25mm in length reduction.  The design requires no holding power and actuation power is very low, offering additional energy savings when compared to traditional clutches.