Solvay’s Torlon Materials Used for the First Time in FTE’s Systems

Solvay, a leading global supplier of high-performance thermoplastics, has reached an important milestone with its recent announcement that its Torlon polyamide-imide (PAI) technology forms a number of key components in a high-performing dual concentric slave cylinder (dCSC) developed by FTE Automotive, a premier producer of automotive drivetrain and brake systems.

Marking the first time Solvay’s Torlon materials have been named for this type of application, FTE Automotive’s dCSC forms the heart of the all-new SGM X44F Dual Clutch Transmission from SAIC General Motors Co., Ltd. The transmission was rolled out on the 2015 Chevrolet Cruze platform for cars built and sold in China.

Concentric slave cylinders are an important core of an automotive clutch system that are positioned directly on the clutch and around the drive shaft. Thus, they are subject to extreme loads every time a car shifts gear. FTE Automotive has a variety of CSC designs for both light and heavy commercial vehicles that, depending on the application, are more commonly fabricated from aluminum or engineering polymers.

According to Brian Baleno, global automotive business development manager for Solvay Specialty Polymers, the inherently high wear-resistance of Torlon makes it a candidate for seal rings and other high-wear applications in both automatic and dual clutch transmissions. He explained that a parallel trend is the progressively frequent replacement of needle bearings with bearings made of Torlon polymers, noting that this conversion enables space savings of approximately 2.5 mm, which enables engineers to downsize metal castings and thus attain huge weight reduction without compromising on reliability or performance.

The hydraulic chambers within FTE Automotive’s dCSC each integrate two seal rings made of Torlon 4275 to ensure dependable and tough performance over the transmission’s lifetime. The seal rings come with small cross-sections with huge diameters. However, they are extremely flexible for easy assembly, thanks to Tolon PAI’s elongation properties.

Torlon 4275 PAI is specially formulated to offer a blend of dimensional stability and wear resistance, enabling the seal rings to ensure constant contact with the cylinder’s chamber walls to maintain cleanliness in the transmission’s high-cycle, high-pressure environment while reducing friction. The material offers a highly durable, tight seal to enable FTE Automotive’s new dCSC to operate reliably despite exposure to dust, dirt and debris, automotive transmission fluids as well as temperatures cycling between -40°C and 160°C.

FTE Automotive selected the Torlon 7130 PAI grade reinforced with 30 percent carbon fiber loading to develop a state-of-the-art locking device that maintains accurate radial positioning within the dCSC throughout the life cycle requirements of the transmission, while contributing little friction and showing low wear. Moreover, the excellent lubricity and fatigue resistance of this grade helps the locking device withstand millions of loading cycles from the clutch’s torsional excitation.

Solvay’s Torlon PAIs merge the performance of thermoset polyimides with the melt-processing advantage of thermoplastics. The beauty of wear-resistance grades is that they deliver unrivaled performance in dry and lubricated environments. Meanwhile, high-strength grades sustain their outstanding strength, toughness and stiffness up to 275°C (527°F), making Solvay’s material the highest performing thermoplastic in the industry.