Hydromechanical system for limiting differential speed between differentially rotating members

A hydromechanical system in combination with a drivetrain subassembly having an input shaft, and first and second output shafts, comprising:

• an interaxle planetary gear assembly including a planet carrier coupled to rotate with said input shaft, a sun gear coupled to rotate with one of said first and second output shafts, a ring gear coupled to rotate with the other of said first and second output shafts, and a plurality of individually rotatable and circumferentially spaced planet gear positioned on said planet carrier in meshing engagement with said sun gear and said ring gear;
• a clutch assembly for selectively coupling said ring gear to rotate with said sun gear;
• a hydraulically actuated piston assembly for applying force on said clutch assembly to actuate said clutch assembly in response to hydraulic pressure such that said ring gear is selectively coupled to rotate with said sun gear;
• a clutch actuating pump, including a reservoir, for supplying hydraulic pressure to said piston assembly to actuate said piston assembly, wherein said clutch actuating pump communicates hydraulic fluid under pressure to said piston assembly in response to differential rotation between said ring gear and said sun gear;
• and
• a second pump in fluid communication with said reservoir of said clutch actuating pump for supplying hydraulic fluid to said reservoir of said clutch actuating pump.

A method of limiting differentiation between first and second rotating members comprising the steps of:

• providing a clutch assembly for selectively coupling said first member to rotate with said second member;
• providing a hydraulically actuated piston assembly for applying force on said clutch assembly to actuate said clutch assembly in response to hydraulic pressure such that said first rotatable member is selectively coupled to rotate with said second rotatable member;
• providing a clutch actuating pump, including a reservoir, for supplying hydraulic pressure to said piston assembly to actuate said piston assembly, wherein said clutch actuating pump communicates hydraulic fluid under pressure from said reservoir to said piston assembly in response to differential rotation between said first and second rotating members;
• supplying a fluid to said reservoir under pressure at least when said clutch actuating pump is not operative to communicate hydraulic fluid from said reservoir to said piston assembly.