Variable ratio steering racks are part of higher quality rack and pinion steering sets, and are desirable because they give superior steering and handling characteristics, including a positive “on center” feel, as well as improved driver safety and comfort. However, the VR rack has a complex geometry which makes it expensive to manufacture using conventional machining processes and methods.
Bishop’s innovation was to design and develop a forging process that could produce VR steering racks, at a price and in volume, ones that surpassed the performance of conventionally machined racks. The innovation involved the refinement of the warm forging process to the point where Bishop’s forged part could successfully compete with a machined part in a critical precision application like a steering rack.
The result is that Bishop’s VR steering racks are stronger, safer, and more durable than traditional broached racks. Due to decreased material content, minimal lubricant usage, and no finish machining, Bishop’s VR racks are also cheaper to produce. Hence, Bishop Steering Technology can enable more economical enjoyment of precision steering and driving, as a consequence of a superior way to manufacture a key component. This is a classic PACE Award case of a “better, faster, cheaper” story executed well.
The realization of this innovation is via a joint venture with Mercedes-Benz Lenkungen GmbH in Schönebeck, Germany. It allowed Bishop’s transformation out of the realm of intellectual property and invention, and into the world of manufactured reality. Bishop produces racks for, among others, Mercedes, Lincoln, and Jaguar. The process is also in use in Japan and Mexico.