Multimatic Inc.

I-Beam Control Arm

The Multimatic I-Beam Control Arm is a stamped and welded steel I-beam lower control arm for McPherson strut suspensions. This innovative suspension component has weight, stiffness, packaging and cost advantages relative to other control arm technologies, and it provides a significant improvement in the performance of McPherson strut suspensions, which are widely used in lower cost, higher volume vehicles. The story of this innovation is a strong one: the technology represents a case of computer modeling overcoming seemingly impossible stamping difficulties, to arrive at an unprecedented level of stiffness cost-effectively. As a product it represents a significant advance in a component critical to driver-perceptible vehicle characteristics.

Multimatic’s intensive use of analysis in computer aided design of parts and tooling has permitted the development of the innovative cross-section in a stamped/welded control arm. The key to the superior stiffness of the new design is the folding of the base material so that it forms a double layer in the flange area of the I-beam cross section. This contrasts to existing box-section arms, which have only 1X base material throughout. In addition, because of the added strength in the Multimatic I-Beam Control Arm, it can be narrower in the neck area of the lower control arm, which provides more space and hence a significantly smaller turning radius. The flange configuration also permits better weld penetration and visual confirmation of weld penetration for better robustness and more consistent parts.

Multimatic I-Beam Control Arm was prototyped in December 2002 and awarded for the 2005 Mustang in February 2003. The many benefits of this innovative control arm permit front suspension performance in the 2005 Mustang that is equivalent to that of more expensive cars. Ford has recognized the contribution of this innovation in the news release on the new Mustang, emphasizing the front suspension and referring specifically to the new control arm and the “groundbreaking manufacturing technology” used to manufacture it.

The new arm has already produced a significant increase in Multimatic sales, and it is expected to be awarded for additional new platforms. The I-beam configuration is under patent application and has the potential of making Multimatic the dominant supplier of McPherson strut lower control arms.