Torque retaining and proportioning differential drive assembly

For use in combination with a vehicle having a four wheel drive arrangement having means providing input power;

• first differential means receiving said input power and providing first and second output shafts, one extending in an aft direction and the other extending in a forward direction, the first differential means proportioning torque and permitting differential rotational speeds between said output shafts;
• a rear differential drive and a front differential drive, each having a separate case, and each being driven at an input end thereof by one of the output shafts of said first mentioned differential means;
• each of said front and rear differential drives including a pair of gear clusters providing for differential rotational movement between an input gear and a pair of output shafts having axes of rotation which are spaced apart control gear means for controlling the amount of differentiation provided in each of said gear clusters between the input gear and the respective output shafts;
• and
• a pair of worms, one drivably coupled to each of said control gears and each worm being rotatably mounted on a respective output shaft, and a worm gear mounted between said worms and permitting rotation of said worms and the associated control gear only when one worm rotates in an opposite direction from the other worm.

A torque proportioning differential drive housed in a gear case and having a common power input and comprising a pair of substantially identical gear sets, each of said gear sets being driven from said common power input, and each gear set comprising a differentiating planetary gear set including a sun gear connected to receive power from the input, planet gears driven by said sun gear and adapted to drivably engage a control gear coaxial with said sun gear;

• the differential drive further including means for controlling rotation of said control gears of both gear sets comprisig a pair of worms, one worm drivably connected to and coaxial with each of said control gears, and a worm gear drivably coupled to both of said worms whereby each of the worms will rotate only when the other worm rotates in an opposite direction;
• separate output drive shaft means, associated with each planetary gear set for carrying loads which change and which result from the need for differentiating in speed of rotation of said output drive shaft means;
• means driven by said planet gears of each gear set and coupled to drive the separate output drive shaft means, said output drive shaft means being, respectively, coaxial with the respective sun gears and extending outwardly of said case, said worms and worm gear cooperating to prevent dissipation of torque and to permit rotation of the control gears as a function of the loads carried when there is a necessity for opposite differentiating rotation.

A torque proportioning differential drive comprising:

• first and second parallel rotating output shafts journaled in bearings in a gear case and driven by a common rotating power input through a substantially identical differential drive gear set mounted on each output shaft;
• a separate control worm rotatably mounted on each output shaft, differentiating rotational speed between the rotating power input and the respective output shafts of gear set being controlled by the control worm rotatably mounted on the respective output shaft;
• a single worm gear rotatably mounted in the gear case perpendicular to and between said output shafts and being engaged by both worms, said differential drive gear sets each comprising a first drive element rotatably mounted on each output drive shaft and receiving power from the common power input, a second driven element coupled to its respective output drive shaft, and a third control element rotationally drivably coupled to the respective worm and rotatably mounted for movement with the worm on the respective output shaft;
• said worms and engaged worm gear controlling the control element of each of said differential drive gear sets for controlling differential rotation of said parallel output drive shafts, the worm gear having a lead angle such that the worm gear cannot rotatably drive either worm and rotates only when the worms rotate in opposite direction to thereby proportion input torque to the output shafts.