Patent ID: 7997154
Filing Date: 2011-08-16
Classification: F16C,G01L

Abstract:
1. A rolling bearing device with a sensor comprising: a tubular fixed bearing ring which is fixed to a vehicle body side; a rotating bearing ring which is rotatably inserted in an interior of the fixed bearing ring and is fixed to a tire side; rolling elements which are rollably disposed between the rotating and fixed bearing rings; and a sensor device disposed on a fixed bearing ring side, wherein the sensor device includes at least two sensors so as to be arranged at positions perpendicular to each other in a circumferential direction of the fixed bearing ring, wherein the sensor device is constructed so as to be able to detect a ground contact load of the tire based on cycles of outputs obtained from the at least two sensors, wherein a number of the rolling elements comprises an odd number, wherein the sensor device includes at least a pair of ultrasonic sensors arranged at positions so as to oppose each other with respect to an axis of the bearing device, wherein if it is assumed that A is a constant, n is the number of rolling elements, V is a vehicle speed, r is a tire radius, Da is a rolling element diameter, θ is a contact angle, and dm is a pitch circle diameter, a rolling element outer ring passage frequency fo, which is expressed by fo=A·n·V/r(1−Da·cos θ/dm), is 50 Hz or more when V≦40 (km/h), and wherein the sensor device is constructed so as to perform a load calculation by using an output of the ultrasonic sensor on a load increasing side and an output of the ultrasonic sensor on a load decreasing side in a zigzag manner between the pair of ultrasonic sensors.