Abstract: A wire winding device which uses a large-sized supply bobbin, which has a large capacity and a large diameter, to highly precisely suppress a variation in tension which variation occurs when a coil is formed by winding a wire material at high speed with the wire material aligned with a winding frame. Rotation (the number of rotation, and timing) of the supply bobbin relative to rotation of the coil is controlled based on the difference between the amount of take-up of the wire material taken up on the winding frame side and the amount of pay-out of the wire material paid out from the supply bobbin, and the control is performed such that the amount of the take-up and the amount of the pay-out agree with each other every moment. This can highly precisely suppress a variation in tension even if there are large differences between inertia of and the diameters of the coil and the supply bobbin.

Abstract: A wire winding device which uses a large-sized supply bobbin, which has a large capacity and a large diameter, to highly precisely suppress a variation in tension which variation occurs when a coil is formed by winding a wire material at high speed with the wire material aligned with a winding frame. Rotation (the number of rotation, and timing) of the supply bobbin relative to rotation of the coil is controlled based on the difference between the amount of take-up of the wire material taken up on the winding frame side and the amount of pay-out of the wire material paid out from the supply bobbin, and the control is performed such that the amount of the take-up and the amount of the pay-out agree with each other every moment. This can highly precisely suppress a variation in tension even if there are large differences between inertia of and the diameters of the coil and the supply bobbin.

Abstract: A motor-driven welding gun has a servomotor for displacing a movable electrode tip toward and away from a fixed electrode tip. The servomotor has a motor housing with a copper pipe which is inserted therein when the motor housing is cast. The copper pipe provides a coolant passage in the motor housing for supplying a coolant therethrough. When the coolant passage is supplied with the coolant, the motor housing is forcibly cooled, reducing the amount of heat generated by the servomotor.

Abstract: A motor-driven welding gun has a servomotor (34) for displacing a movable electrode tip (30) toward and away from a fixed electrode (32). The servomotor (34) has a motor housing (38) with a copper pipe (72) which is inserted therein when the motor housing (38) is cast. The copper pipe (72) provides a coolant passage (70) in the motor housing (38) for supplying a coolant therethrough. When the coolant passage (70) is supplied with the coolant, the motor housing (38) is forcibly cooled, reducing the amount of heat generated by the servomotor (34).