Transmission Side Cover Design Optimization for NVH Part 2: Geometric Optimization Studies

The design of Front Wheel Drive transmission side covers is primarily driven by packaging concerns, and secondarily by structural durability requirements. While the side cover design is a very important element in the NVH performance of a transaxle, there has historically been little consideration of this concern at the design stage.

The typical approach to NVH considerations on a side cover is to start with the initial prototype hardware and add any stiffening features in order to reduce the cover vibration or radiated sound. A preferred approach would be to factor the NVH considerations into the initial design. Through consideration of the packaging constraints and a goal of maximizing the fundamental natural frequency of the side cover, it is possible to select from various alternative geometries the one which best meets these objectives. Present day geometry optimization algorithms available in high-end Computer Aided Design packages provide an automated process of achieving this goal.

Part 1 of this paper presented the first phase in addressing this design goal through a consideration of the relative benefits of introducing shell curvature to a flat plate geometry. This part presents the extension to the three dimensional geometric consideration with consideration of package constraints. The results show the benefits and practicality of using geometric optimization in determination of an improved side cover design from an NVH perspective.