Patent ID: 6913390
Filing Date: 2005-07-05
Classification: B23Q,F16C,H02K,Y10S,Y10T

Abstract:
1. A rotating shaft apparatus for rotationally driving a shaft characterized by a housing; a shaft rotatably supported in the housing by a cylindrical roller bearing or a radial ball bearing, which has a larger diameter, at the loaded side thereof and by a pair of angular ball bearings, which have a smaller diameter, at the opposite side; means for detecting the rotational weed of the shaft; a drive motor for rotationally driving the shaft; first cooling means, having a cooling passage defined in the shaft along the center axis thereof, for cooling the shaft with a coolant supplied into the coolant passage; second cooling means, having a coolant passage defined in the housing, for cooling the shaft with the coolant supplied into the coolant passage; inner race temperature detecting means for detecting the temperature of the inner race of the bearing for rotationally supporting the shaft at the loaded side; outer race temperature detecting means for detecting the temperature of the outer race of the bearing for rotationally supporting the shaft at the loaded side; the first cooling means controlling the temperature of the coolant to be supplied into the cooling passage of the shaft on the basis of the temperature of the inner race detected by the inner race temperature detecting means, and the second cooling means controlling the temperature of the coolant to be supplied into the cooling passage of the housing on the basis of the temperature of the outer race detected by the outer race temperature detecting means; and the second cooling means calculating a target temperature difference between the inner and the outer races which provides an appropriate internal pressure in the bearing for rotationally supporting the shaft at the loaded side on the basis of the rotational speed of the coolant detected by the rotational speed detecting means, and controlling the temperature of the coolant to be supplied into the coolant passage of the housing so that the temperature of the outer race of the bearing is higher than that of the inner race of the bearing by the calculated target temperature difference.