Patent ID: 9186938
Filing Date: 2015-11-17
Classification: B60C

Abstract:
1. A wheel position detector for a vehicle, the vehicle including a body and a plurality of wheels mounted on the body, each wheel equipped with a tire, the wheel position detector comprising: a plurality of transmitters, each transmitter mounted on a corresponding wheel and having unique identification information, each transmitter including a first control section for generating and transmitting a data frame containing the unique identification information; a receiver mounted on the body of the vehicle and including a second control section and a reception antenna, the second control section configured to receive the frame via the reception antenna from one of the plurality of transmitters at a time, the second control section configured to perform wheel position detection, based on the frame, to specify one of the plurality of wheels on which the one of the plurality of transmitters is mounted, the second control section configured to store a relationship between the one of the plurality of wheels and the unique identification information of the one of the plurality of transmitters, and a plurality of wheel speed sensors, each wheel speed sensor provided with a gear rotating with the corresponding wheel, the gear including a plurality of teeth having electrical conductivity and a plurality of intermediate portions alternately arranged with the plurality of teeth along an outer periphery of the gear so that a magnetic resistance of the gear changes along the outer periphery, each wheel speed sensor configured to output a tooth detection signal indicative of a passage of each of the plurality of teeth, wherein when the second control section receives another frame containing unique identification information of a transmitter mounted on a wheel of another vehicle during the wheel position detection, the second control section performs the wheel position detection based on the frame including the other frame, each transmitter further includes an acceleration sensor configured to output an acceleration detection signal indicative of acceleration having a gravity acceleration component varying with a rotation of the corresponding wheel, the first control section detects an angle of the transmitter based on the gravity acceleration component of the acceleration detection signal from the acceleration sensor, the transmitter forms the angle with a central axis of the corresponding wheel and a predetermined reference zero point on a circumference of the corresponding wheel, the first control section repeatedly transmits the frame each time the angle of the transmitter reaches a transmission angle, the second control section acquires gear information indicating a tooth position of the gear based on the tooth detection signal from the wheel speed sensor when the receiver receives the frame, the second control section sets a first variation allowable range based on the tooth position, the second control section excludes a certain wheel from a candidate of the one of plurality of wheels unless the tooth position of the gear rotating with the certain wheel falls within the first variation allowable range a predetermined number of times in a row, and the second control section registers a remaining wheel as the one of plurality of wheels.