PHOTO: Solvay’s Torlon polyamide-imide (PAI) technology forms several key components in a high-performing dual concentric slave cylinder (dCSC) developed by FTE Automotive, a premier producer of automotive drive train and brake systems
SOLVAY Specialty Polymers’ Torlon® polyamide-imide (PAI) technology forms several key components in a high-performing dual concentric slave cylinder (dCSC) developed by FTE Automotive, a premier producer of automotive drivetrain and brake systems.
Signaling the first time Solvay’s Torlon materials have been specified for this type of application, FTE Automotive’s dCSC forms the heart of the new SGM X44F Dual Clutch Transmission from a leading automaker, SAIC General Motors Co. The transmission was successfully launched on the 2015 Chevrolet Cruze platform for vehicles produced and sold in China.
The critical core of an automotive clutch system, concentric slave cylinders are positioned directly around the drive shaft and on the clutch. They are consequently subject to extreme loads each time a car shifts gear. FTE Automotive offers various CSC designs for light and heavy commercial vehicles that, depending on the application, are more typically fabricated from aluminium or engineering polymers.
The intrinsically high wear-resistance of Torlon PAI makes it a natural candidate for seal rings and other high-wear applications in both dual clutch and automatic transmissions. A parallel trend is the increasingly frequent replacement of needle bearings with bearings made of Torlon polymers. This conversion allows space savings of about 2.5mm, which allows engineers to downsize metal castings and thereby achieve significant weight reduction without compromising on performance or reliability.
Both hydraulic chambers within FTE Automotive’s dCSC each incorporate two seal rings made of Torlon 4275 to ensure reliable and durable performance over the transmission’s lifetime. The seal rings have small cross-sections with relatively large diameters. Yet, due to Torlon PAI’s elongation properties, they maintain flexibility for easy assembly.
Formulated to provide an excellent combination of wear resistance and dimensional stability, Torlon 4275 PAI allows the seal rings to ensure consistent contact with the cylinder’s chamber walls to maintain cleanliness in the transmission’s high-cycle, high-pressure environment while minimizing friction. The material provides a durable, tight seal to allow FTE Automotive’s new dCSC to operate reliably despite constant exposure to dirt, dust and debris, automotive transmission fluids and temperatures cycling between -40°C and 160°C.
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