PAI delivers high strength in clutch system from FTE Automotive

  • PAI used to fabricate sealing rings and locking mechanism
  • High strength, resistant to transmission fluids
  • FTE Automotive’s innovative dual concentric slave cylinder

Polyamide-imide (PAI) technology is used for 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 automaker, SAIC General Motors Co., Ltd. The transmission was launched on the 2015 Chevrolet Cruze platform for vehicles produced and sold in China.

Concentric slave cylinders are subject to extreme loads

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 aluminum or engineering polymers.

Both hydraulic chambers within FTE Automotive’s dCSC each incorporate two seal rings made of Torlon 4275 to ensure durable performance over the transmission’s lifetime. The seal rings have small cross-sections with relatively large diameters. Yet, due to the material’s elongation properties, they maintain flexibility for easy assembly.

dual concentric slave cylinder (dCSC)

Polyamide-imide (PAI) technology forms several key components in a dual concentric slave cylinder (dCSC) developed by FTE Automotive, a producer of automotive drive train and brake systems (Source: FTE Automotive)

Resistant to transmission fluids and high temperatures

The PAI material also 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 (-40°F and 320°F).

30% carbon fiber reinforced PAI for locking device

FTE Automotive chose a different grade, Torlon 7130 PAI reinforced with 30 percent carbon fiber loading, to fabricate a locking device that maintains precise radial positioning within the dCSC throughout the transmission’s life cycle requirements, while contributing very little friction and exhibiting extremely low wear. In addition, the very good lubricity and fatigue resistance of this grade enables the locking device to withstand millions of loading cycles from the torsional excitation of the clutch.
In gneral, Solvay’s range of PAI materials combine the performance of thermoset polyimides with the melt-processing advantage of thermoplastics. Wear-resistance grades can be used in both dry and lubricated environments. High-strength grades retain their toughness, strength and stiffness up to 275°C (527°F). Its broad chemical resistance includes strong acids and most organics.


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