New Rack and Pinion Steering Design and Manufacturing Technology

The justification for variable-ratio rack and pinion steering is discussed in the context of the modern front-wheel-drive car. The rack tooth geometry associated with this new steering technology prompted the development of a rack forging process which enables the forming of the entire rack cross-section in a single blow. The die is essentially flashless and enables the simultaneous forming of the variable-ratio teeth and a ‘Y’ shaped rack section. The evolution of the ‘Y’ die design and associated processes is described in some detail, together with methods of gauging variable-ratio racks.