Drive system for electric vehicles

Abstract

A dual-rotor electric motor (1), having an outer rotor (3) and an inner rotor (4), drives a first drive axle (5) and a second drive axle (6), while also provides inter-axle speed differential function. One of the drive axles is also a steering axle. Torque and rotation are transmitted between the outer rotor and the first drive axle through a clutch (19) and a first drive shaft (20), and between the inner rotor and the second drive axle through a second drive shaft (22). A first brake (24) brakes the rotation of the outer rotor, and a second brake (25) brakes the rotation of the inner rotor. A fluid pressure source, including a pump (51) and an accumulator (59), provides fluid pressure, through a plurality of fluid lines, for operating the clutch and brakes. Electromagnetic control valves (60, 61, 62) control the operation of the clutch and brakes. An electronics (78) monitors and compares continuously the rotational speeds of the axles and controls the valves for engaging the clutch and releasing the first brake when a speed lower than a predetermined value is detected, whereby providing low-speed/four-wheel-drive mode, or disengaging the clutch and applying the first brake when a speed higher than a predetermined value is detected, whereby providing high-speed/two-wheel-drive mode, or applying the first brake or the second brake when a traction slip respectively of the first drive axle or of the second drive axle higher than a respective predetermined value is detected, whereby providing anti-slip traction control.

Dependencies are inferred from the claim text.