This paper discusses the development of a power divider clutch for use in 630kw class chemical fire fighting vehicles for operation in airports. Since discs are required to slip at contact pressure under 100kPa, reduction in actual disc contact area due to disc surface imprecision was foreseen as being a major problem. Having derived the actual contact areas and clutch temperature both through numerical analysis based on FEM and actual experimentation, we are able to confirm that the results of our analysis and experimentation show excellent agreement.
Next, we adopted an ECMV (Electric Control Modulation Valve) (*1) for clutch hydraulic control which improved the fine control of vehicle speed. In addition, we were able to facilitate maintenance by replacing the mechanical linkage with an electrical system. Through effective use of a microprocessor, we also succeeded in adding a protect function to safeguard against abnormal use and an effective diagnostic system.