AUTOMOTIVE DIFFERENTIALS PARTICULARLY FOR USE IN MULTIPLE DRIVING AXLE VEHICLE

1394886 Differential gear BORG-WARNER CORP 23 Aug 1972 [20 Sept 1971] 39291/72 Heading F2D In a differential suitable for a four-wheel drive vehicle and having an input shaft, two output shafts and a fluid operated friction clutch adapted to couple together two of the shafts, a control device responsive to the speed ratio between two of the shafts is adapted to supply fluid to the clutch to effect coupling when the speed ratio exceeds predetermined limits. As shown, the differential comprises a planet carrier 70, driven by an input shaft 30, a ring 68 secured to the output shaft 53, and a sun 66 on a sleeve shaft 52, which drives the output shaft 50 through gears 54, 56. An hydraulically operated friction clutch 58 acts between the sun 66 and ring 68 (i.e. between shafts 52, 53), and is connectible to a pressure fluid source through passages in the shafts 52, 30 and a normally-closed valve 64. The valve 64 comprises a valve member 116, rotatable on the input shaft 30 and formed with axial passages 118 adapted to connect radial passages 109, 110 in the shaft 30. An annular disc 120 is keyed to the shaft 30 and is formed with openings receiving springs which engage in pockets in the side of valve member 116 to normally position the valve member to disconnect the passages 118 from the passages 109, 110. The valve 64 is controlled by one-way clutches 60, 62 supported on the sleeve portion of a wheel 134 which is connected to the valve member 116 by a spring belt 136. Wheels 140, 142 of clutches 60, 62 are rotated by belts 148, 149 engaging stepped surfaces of the shaft 52, and are so related to the wheel 134 that the wheel 140 rotates 0À88 slower than, and the wheel 142 rotates 1.02 faster than, the wheel 134. In operation, in the case of front or rear wheel spin, one or other of the clutches 60, 62 will engage and, through the wheel 134, cause relative rotation of the valve member 116 and the shaft 30, thereby opening the valve 64 to cause actuation of the clutch 58. In a further embodiment, Fig. 8 (not shown), the valve arrangement 64 is replaced by a positive displacement bidirectional pump which is provided with inner and outer rotors, the inner rotor being keyed to the input shaft, and the pump housing rotating with the shaft 52, the arrangement being such that in the event of loss of traction of a front or rear wheel of the vehicle, relative rotation of the pump elements causes pressure fluid to engage the clutch 58 through a centrifugal control valve.