초록 ▼

An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary axles an

An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary axles and a microcontroller. The sensors include a vehicle speed sensor, a pair of primary and secondary drive shaft speed sensors, and brake and driveline status sensors. The transfer case includes a modulating electromagnetic clutch controlled by the microcontroller which is incrementally engaged to transfer torque from the primary output shaft to the secondary output shaft. When the speed of either the front or the rear drive shafts overruns, i.e., exceeds, the speed of the other drive shaft by a predetermined value related to the vehicle speed, indicating that wheel slip is present, clutch current is incrementally increased to increase clutch engagement and torque transfer to the secondary axle. When wheel slip is reduced below the predetermined value the current to the clutch is incrementally reduced. The method of operating such a system is also described.

대표청구항 ▼

[ We claim:] [1.]1. A drive system for a motor vehicle having a primary front drive line and secondary rear drive line comprising, in combination,a transmission having an output,a primary drive assembly located in a forward portion of the vehicle and having axles, wheels and a primary differential h

[ We claim:] [1.]1. A drive system for a motor vehicle having a primary front drive line and secondary rear drive line comprising, in combination,a transmission having an output,a primary drive assembly located in a forward portion of the vehicle and having axles, wheels and a primary differential having an input driven by said transmission output,a secondary drive assembly located in a rearward portion of the vehicle and having axles, wheels and a secondary differential having an input, anda friction clutch assembly having an input driven by said transmission output and an output driving said input of said secondary differential, said friction clutch assembly including an electromagnetic coil, a rotating armature, a plurality of interleaved clutch plates and a force applying operator including a pair of coaxial cam members defining opposed grooves receiving ball members operably disposed between said electromagnetic coil and said plurality of interleaved clutch plates.