Freudenberg Sealing Technologies and Solvay Specialty Polymers have developed a unique component that helps enable production of General Motors’ Hydra-Matic 8L90 8-speed transmission.
The High-Load, High-Shear Geared Axial Polymer Thrust Washer (HLHS GAP Thrust Washer), designed to replace thrust washers made of sintered metal or aluminium, was tested and validated in record time to support the auto manufacturer’s critical launch schedule. Collaboration between Freudenberg, Solvay and GM assured the project’s success and earned it finalist honours in the Powertrain category of the 44th annual 2014 Society of Plastics Engineers’ (SPE’s) Automotive Innovation Awards Competition.
The Automotive Division of SPE promotes scientific and engineering knowledge relating to plastics developments in the global transportation industry. Its prestigious competition annually draws 60-80 project entries from vehicle manufacturers, suppliers and polymer producers.
“We are pleased that SPE has recognized the HLHS GAP Thrust Washer as a finalist in its Automotive Innovation Awards competition. This project represents a powerful amalgamation of new technology, industry collaboration, rapid customer response and lean manufacturing,” said Dr. Luis Lorenzo, senior vice-president, Technology and Innovation, Freudenberg Sealing Technologies. “These are, in fact, business attributes that Freudenberg and Solvay regularly offer customers.”
The HLHS GAP Thrust Washer offers superior friction and wear properties at elevated pressures and velocities. Freudenberg and Solvay worked together to design and test a thrust washer using Solvay’s Torlon 4275 polyamide-imide (PAI) resin, a plastic with the highest strength and stiffness of any thermoplastic up to 275deg C (525deg F). The material offers outstanding resistance to wear, creep, and chemicals – including strong acids and most organics – and is ideally suited for severe service environments.
“The HLHS GAP Thrust Washer program provides both a template and benchmark for future component program success and opens opportunities for continued metal replacement in powertrain applications,” said Brian Baleno, global automotive business manager for Solvay Specialty Polymers.
Freudenberg and Solvay collected broad performance data on Torlon 4275 when developing the thrust washer. Solvay used a six-lot resin testing system to gather information relating to tensile strength, resistance to transmission fluid, and heat aging. In addition, Solvay demonstrated the material’s fit in lubricated friction and wear environments via its proprietary ASTM D3702-based friction and wear test rig.
Freudenberg used proprietary equipment to test the thrust washer under extreme conditions to provide assurance that the new component met performance requirements. The company’s unique thrust washer machine uses air pressure to apply upwards of 3000 lb. of pressure on the bearing, and has the capability of spinning at 10,000 rpm. The machine also regulates oil temperature, oil flow rate, and runs components at an angular offset thanks to a unique leveling platen.
Data generated by Freudenberg and Solvay was critical in successfully validating the replacement of metallic components with an advanced thermoplastic design. This test capability opens new avenues for further use of the material and the manufacturing process to replace other transmission components.
“OEM vehicle manufacturers seeking to replace traditional metal components with new thermoplastic designs must have assurances that new materials can be designed, validated, and produced to meet weight and extended performance requirements while also addressing fundamental issues such as cost, quality, delivery, and manufacturability,” said Rory Pawl, sales director, Process Seals, and former director, Future Technology, Freudenberg Sealing Technologies.
Freudenberg is producing the HLHS GAP Thrust Washer in Findlay, Ohio using its innovative Single Cavity Net Shape Molding process. The process, which uses compact, custom-engineered one-cavity injection molding machines, improves part quality and reduces engineered waste, scrap and costs.
In fact, Single Cavity Net Shape Molding has reduced the plant’s rejected parts per million (ppm) by a factor of 20 since its implementation. The process also eliminates additional prototyping requirements, supplemental production steps, and unpredictable manufacturing variables.
“We have set a benchmark with this component and this project,” Pawl concluded. “As growing demands for better fuel economy, lower emissions, tighter packaging and longer component life drive manufacturers to explore new powertrain performance options, we are ready to assist them with superior solutions.”