Wheel position detecting device and tire pressure detecting apparatus having the same
First Claim
1. A wheel position detecting device for a vehicle having a vehicle body and a plurality of wheels, the wheel position detecting device comprising:
- a transmitter being integrated to each of the plurality of wheels, the transmitter including a first control unit, the first control unit generating and transmitting a frame including identification information specific to the transmitter; and
a receiver being integrated to the vehicle body, the receiver including an antenna and a second control unit, the second control unit receiving the frame transmitted from the transmitter through the antenna, the second control unit performing a wheel position detection to specify which of the plurality of wheels the transmitter transmitting the frame is integrated to and to store a relationship between the identification information of the transmitter and the wheel to which the transmitter is integrated, whereinthe transmitter includes an acceleration sensor that outputs a detection signal according to an acceleration containing a gravitational acceleration component that varies with rotation of the wheel to which the transmitter is integrated,the first control unit-detects an angular position of the transmitter relative to a reference position, based on the gravitational acceleration component provided by the detection signal of the acceleration sensor, the reference position being set at any position in a circumferential direction of the wheel to which the transmitter is integrated, andthe first control unit transmits the frame when the transmitter is at a transmission angular position,the wheel position detecting device further comprising;
a wheel speed sensor being provided for each of the wheels to detect a tooth of a gear that rotates in association with a corresponding wheel, the gear including conductive portions as teeth and intermediate portions between the conductive potions, the intermediate portions having a magnetic resistance different from the conductive portions, whereinthe second control unit acquires gear information indicating a tooth position of the gear based on a detection signal of the wheel speed sensor,in the wheel position detection, the second control unit sets a variation allowance range based on the tooth position at a reception timing of the frame and determines whether the tooth position at a subsequent reception timing of the frame is within the variation allowance range, and when the tooth position of the gear at the subsequent reception timing is not within the variation allowance range, the second control unit excludes the wheel corresponding to the gear a from a candidate wheel until one wheel remains, and registers a remaining wheel as the wheel to which the transmitter is integrated, andthe second control unit prevents the wheel position detection when a wheel speed detected based on a detection signal of the wheel speed sensor is equal to or lower than a predetermined threshold, and performs the wheel position detection only when the wheel speed is higher than the predetermined threshold.
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Accused Products
Abstract
In a wheel position detecting device, a receiver acquires gear information indicating a tooth position of a gear rotating in association with a corresponding wheel at a predetermined interval. In a wheel position detection, the receiver sets a variation allowance range based on the tooth position at a reception timing of a frame transmitted from a transmitter integrated to each wheel. When the tooth position of the gear at a subsequent reception timing of the frame is not within the variation allowance range, the receiver excludes the wheel corresponding to the gear from a candidate wheel. The receiver registers the wheel remaining last as the wheel to which the transmitter is integrated. The receiver performs the wheel position detection only when a wheel speed is higher than a predetermined threshold, so that the wheel position detection is performed based on an accurate tooth position.
7 Citations
9 Claims
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1. A wheel position detecting device for a vehicle having a vehicle body and a plurality of wheels, the wheel position detecting device comprising:
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a transmitter being integrated to each of the plurality of wheels, the transmitter including a first control unit, the first control unit generating and transmitting a frame including identification information specific to the transmitter; and a receiver being integrated to the vehicle body, the receiver including an antenna and a second control unit, the second control unit receiving the frame transmitted from the transmitter through the antenna, the second control unit performing a wheel position detection to specify which of the plurality of wheels the transmitter transmitting the frame is integrated to and to store a relationship between the identification information of the transmitter and the wheel to which the transmitter is integrated, wherein the transmitter includes an acceleration sensor that outputs a detection signal according to an acceleration containing a gravitational acceleration component that varies with rotation of the wheel to which the transmitter is integrated, the first control unit-detects an angular position of the transmitter relative to a reference position, based on the gravitational acceleration component provided by the detection signal of the acceleration sensor, the reference position being set at any position in a circumferential direction of the wheel to which the transmitter is integrated, and the first control unit transmits the frame when the transmitter is at a transmission angular position, the wheel position detecting device further comprising; a wheel speed sensor being provided for each of the wheels to detect a tooth of a gear that rotates in association with a corresponding wheel, the gear including conductive portions as teeth and intermediate portions between the conductive potions, the intermediate portions having a magnetic resistance different from the conductive portions, wherein the second control unit acquires gear information indicating a tooth position of the gear based on a detection signal of the wheel speed sensor, in the wheel position detection, the second control unit sets a variation allowance range based on the tooth position at a reception timing of the frame and determines whether the tooth position at a subsequent reception timing of the frame is within the variation allowance range, and when the tooth position of the gear at the subsequent reception timing is not within the variation allowance range, the second control unit excludes the wheel corresponding to the gear a from a candidate wheel until one wheel remains, and registers a remaining wheel as the wheel to which the transmitter is integrated, and the second control unit prevents the wheel position detection when a wheel speed detected based on a detection signal of the wheel speed sensor is equal to or lower than a predetermined threshold, and performs the wheel position detection only when the wheel speed is higher than the predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification