Continuously variable transmission

A transmission for a four-wheel drive vehicle including an engine and primary and secondary drivelines comprising:

• a first shaft adapted to be driven by the engine;
• a second shaft;
• a differential having a first component driven by said first shaft, a second component driving said second shaft, and a third component;
• a first worm gearset including a first worm gear fixed to said third component of said differential and a first worm meshed with said first worm gear;
• a third shaft adapted for connection to the primary driveline;
• a second differential having a first component driven by said second shaft, a second component driving said third shaft, and a third component;
• a second worm gearset including a second worm gear fixed to said third component of said second differential and a second worm meshed with said second worm gear;
• and
• a second electric motor for selectively driving said second worm so as to vary a speed ratio between said second shaft and said third shaft.

A transmission comprising:

• an input shaft;
• an intermediate shaft;
• a differential operably installed between said input shaft and said intermediate shaft and including a first input member, a second input member;
• and an output member coupled to said intermediate shaft, and a drive member;
• a worm gearset including a worm gear coupled to said drive member and which is meshed with a worm;
• an electric motor operable for driving said worm;
• and
• a mode selector mechanism operable in a first mode to releaseably couple said first input member to said input shaft and in a second mode to releaseably couple said second input member to said input shaft.

A transmission for use in a motor vehicle having an engine and a primary driveline, comprising:

• a first shaft adapted to be driven by the engine;
• a second shaft adapted to drive the primary driveline;
• a gearset including a first sun gear, a second sun gear fixed for rotation with said second shaft, a ring gear, and pinion gears rotatably supported by a carrier and operably meshed with said first and second sun gears and said ring gear;
• a coupling operable for selectively establishing a drive connection between said first shaft and at least one of said first sun gear and said ring gear;
• a worm gearset having a worm meshed with a worm gear, said carrier being fixed for rotation with one of said worm and worm gear;
• and
• a drive unit for selectively driving the other of said worm and worm gear.

A transmission for a motor vehicle having an engine and a driveline, comprising:

• a first shaft adapted to be driven by the engine;
• a second shaft adapted to drive the driveline;
• a differential having a first component driven by said first shaft, a second component driving said second shaft, and a third component operably interconnecting said first component to said second component;
• a mode coupling for selectively coupling and uncoupling said first component relative to said first shaft;
• a worm gearset having a worm having at least one thread meshed with teeth of a worm gear, said worm gear having less than twenty four teeth and being secured for rotation with said third component;
• and
• an electric motor for selectively driving said worm for varying a speed ratio between said first and second shafts.