is output from a servo motor 901, the rotational driving force output from the servo motor 901 is input via the gears 902 and 903 into a specific crankshaft 905 of a speed reducer 904, and input into the remaining crankshafts 910 of the speed reducer 904 via a gear 903 disposed at the top end of the crankshaft 905, a gear 908 supported by the bearings 906 and 907 so that the rotational axis maybe on the same straight line as the rotational axis of the speed reducer 904, and a gear 909.
The speed reducer 904 rotates the body of rotation 920 with respect to an anchor block 930 secured in the floor in accordance with a rotational driving force input into the crankshafts 905 and 910,if the rotational driving force is input into the crankshafts 905 and 910.
As above described, the joint 900 of the industrial machine rotates the body of rotation 920 with respect to the anchor block 930 secured in the floor, if a rotational driving force output from the servo motor 901 is input into the plurality of crankshafts 905 and 910 of the speed reducer 904.
Accordingly, in the joint of the conventional industrial machine, since the rotational driving force output from the servo motor is input in equal quantity into the plurality of crankshafts of the speed reducer, it is possible to prevent the life of the speed reducer, particularly, the life of the crankshafts from being shorter.
However, in the joint of the conventional industrial machine as described above,