Microcellular Polyurethane Jounce Bumper Design and the Effects on Durability

Microcellular polyurethane (MCU) jounce bumpers are the most commonly used jounce bumpers in the industry. MCU is the best material available due to its high durability, better ride and handling performance and superior overall performance. While a simple material swap to MCU is often enough to significantly improve performance, there are design features other than material that significantly affect the final component durability. Robust jounce bumper design features will virtually assure a durable and cost effective finished part. The early stages of the design cycle are most critical when designing any part. This is when cost is designed out, quality is designed in, and durability is assured. The objective of this paper is to examine how the geometric design of a jounce bumper effects the overall component durability. An in depth analysis of height to diameter ratio, lateral expansion, convolute design and placement, and generally accepted jounce bumper design principles will be given. The effects of external retainer ring attachment will also be addressed.

Detailed drawings and analytical tools are used to illustrate the relationship between good design principles and good durability performance of the jounce bumper.