Electric Bus Transmission Washer

Electric Bus Transmission Washer

Project Details

Application: Electric bus transmission

Material: Torlon®

Customer: Fortune 500 commercial transportation transmission manufacturer

Industry: Automotive

Timeline: 4 months from first contact to successful testing of the solution

We suggested the material, Torlon 4275, and within three weeks…we designed, machined and delivered prototype parts.

The Objective

Convert a DU washer to a high-performance polymer washer that can fit within the existing design space as a drop-in replacement.

The Challenge

A Fortune 500 commercial transportation transmission manufacturer was experiencing high failure rates in its DU-coated pinion thrust washers that were used within a planetary gear set in an electric bus transmission. The premature failures of the metal DU washer led to excessive warranty expenses.

The extremely high rotational speed and the weight of the metal washer caused it to generate a lot of centrifugal force when rotated at high speeds. This centrifugal force caused the inside diameter of the DU washer to wear away and take an oblong shape.

The customer was interested to learn whether a high-performance polymer washer would have a longer life expectancy under the required high velocity. Needing a quick solution to replace the existing units under warranty and to supply units for current and future production, Allegheny Performance Plastics was asked to convert a metal DU washer to a high-performance polymer washer that can fit within the existing design space as a drop-in replacement.

The Solution

Our engineering team quickly obtained the relevant application conditions—load, velocity, and environmental conditions—from the customer to research the appropriate high- performance polymer for this application. In-house developed tribological test data was readily available and used to support the prototype design and material selection. We suggested the material, Torlon® 4275, and within three weeks from our initial meeting with the customer, we designed, machined, and delivered prototype parts. Learn more about Torlon here. Within 12 weeks, we were delivering PPAP-approved production parts.

Because the high-performance polymer washer has significantly less mass than the metal washer, the centrifugal force generated is significantly lower, which reduces product failures due to excessive wear and tear in the field. The result was a very successful product development that is still in production today without a single part failure. At Allegheny Performance Plastics, we have access to experienced team members and tribology testing equipment to solve problems, examine parts or materials, test ideas, and ensure precision in production runs with critical or sensitive issues.

“The problem posed to us was a part failure – the metal part was wearing out prematurely. Not only were we able to solve that problem immediately with our Torlon polymer replacement, but there was an added benefit of a significant reduction in NVH,” said Greg Shoup, Allegheny Performance Plastics President.

Our team will support your project with a mindset of curiosity, a strength of data-based advice, and state-of-the-art polymer injection molding and testing facilities. We deliver the quality, performance, and timeliness your ind