Patent ID: 8176799
Filing Date: 2012-05-15
Classification: F16C,G01D,G01L,Y10T

Abstract:
1. A state measuring apparatus for a rolling bearing unit, the device comprising: a rolling bearing unit equipped with an outer ring that has double row outer ring raceways on an inner peripheral surface and is not rotated in use, a hub that has double row inner ring raceways on an outer peripheral surface and is rotated in use, and a rolling element that is provided rotatably in plural in each row between the double row inner ring raceways and the double row outer ring raceways; and a state measuring apparatus equipped with an encoder, at least one sensor, and a calculating unit; wherein the encoder is attached to an end portion of the hub concentrically with the hub and has a cylindrical sensed surface concentrically with the hub, a characteristic of which being changed alternately with respect to a circumferential direction, wherein the sensor is held in a cylindrical cover, which is made of metal and with bottom and fixed to the end portion such that an end portion opening of the outer ring is covered in a state that a sensing portion is opposed to the sensed surface of the encoder via a sensor holder made of synthetic resin and changes an output signal in response to a change in the characteristic of the sensed surface, wherein the calculating unit has a function of calculating at least one status variable of a relative displacement between the outer ring and the hub and an external force applied between the outer ring and the hub, based on the output signal of the sensor, and wherein the sensor holder has an annular portion that holds at least the sensor, and is attached to the cylindrical portion via a holding ring in a state that the holding ring fixed to an inner peripheral surface of a cylinder portion constituting the cover is embedded in an intermediate portion of the annular portion in the axial direction.