TORQUE MEASUREMENT DEVICE FOR GEAR TRANSMISSION DEVICE, DRIVING SYSTEM CONTROL DEVICE, AND PRELOAD MEASUREMENT METHOD FOR ROLLER BEARING

PROBLEM TO BE SOLVED: To provide a practical structure such that output torque of an engine 1 is measured and even the engine 1 which has deteriorated with time or is fed with fuel other than specified fuel can be brought under suitable control corresponding to respective states.SOLUTION: A torque measurement device includes a torque measuring instrument 4 which finding torque that a speed change gear 2 transmits. The torque measuring instrument 4 includes an encoder which is supported and fixed to an inner ring of a roller bearing rotating with torque proportional to the crank shaft of the engine 1 and supporting a rotating shaft, a sensor which has a detection part opposed to a detected surface of the encoder while supported at the fixed part, and a torque computing unit which computes the torque of the rotating shaft on the basis of the output signal of the sensor. Then an engine controller 3 adjusts the amount of fuel supplied to the engine 1 and the speed change ratio of the speed change gear 2 on the basis of a value of the torque that the torque computing unit computes.