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Products & services
D and V-shaped steering racks
Bishop variable ratio steering racks are manufactured in a warm forging process developed by the company, and provide a high level of flexible ratio characteristic. This means the ratio can be designed quickly in a variety of ways - for considerably higher levels of safety and a noticeable increase in driving comfort for consumers.
A warm forging process is used so there is sufficient scope for a variety of formats and cross-section designs.
Our ActivRakTM VR steering racks have a unique form of variable ratio, where the rack gain characteristic is tuned to achieve a particular vehicle yaw gain target. This yaw gain target is consistent with what might be achieved using an angle overlay active steering system but at negligible cost and without any additional components or systems. ActivRakTM steering racks with variable ratio have a ratio which is over 25% higher at a pinion rotation of less than 170° from the on-centre position - and often even 90° or less.
Our variable ratios offer the possibility of multiple ratio changes. Applications with two or more ratio changes are referred to as 'M-Curve' VR. Some existing power assistance systems cannot support the fast ratios required for improved vehicle dynamics at full lock. The use of a second (slower) ratio at lock directly reduces the assistance torque required at lock in column driven assisted steering systems (CEPAS). This same approach reduces the rack speed at lock in rack driven assisted steering systems (REPAS or HPAS), indirectly achieving a similar benefit. The result is increased steering performance without increasing the power assistance requirement.
The Bishop ATS Power Steering Valves allow low noise levels to be achieved without the need for accurate high cost input shaft metering edge grinding. The valve uses an innovative fluid arrangement resulting in substantial reductions in fluid cavitation. Our ATS valves also provide high levels of design flexibility in the boost characteristic.
The Bishop On-Center detent (OCD) system offer dramatically improved on-center steering stiffness for medium-speed and high-speed driving, for example on motorways, without any increase in steering effort and steering gear friction. The system is adaptable to most rotary valve formats.
Bishop VARIATRONIC is a speed-sensitive power steering solution which offers complete flexibility in pressure behaviour as a function of vehicle speed. The number of additional components required, compared to a standard rotary valve, are minimal.