TIRE AIR PRESSURE MONITORING DEVICE
1 Assignment
0 Petitions
Accused Products
Abstract
A tire air pressure monitor device is provided for monitoring air pressure in tires using pressure sensors, which are installed in the tire of each wheel. Each wheel has a transmitter for wirelessly transmitting the air pressure information along with a sensor ID when the wheel is at a predetermined rotation position. A vehicle body has a receiver for receiving the wireless signals. A wheel speed sensor is provided on a vehicle body for each wheel to determine the wheel rotation position. A TPMS control unit acquires the wheels rotation position when a wireless signal containing a certain sensor ID is transmitted. The TPMS control unit accumulates wheel rotation position data, and determines the wheel position corresponding to the wheel rotation position data having the smallest degree of dispersion from among the wheel rotation position data as the wheel position for the transmitter corresponding to the sensor ID.
26 Citations
22 Claims
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1. (canceled)
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2. A tire air pressure monitor device that monitors air pressure in tires, the tire air pressure monitor device comprising:
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a tire air pressure sensor configured to be installed on wheels of the tires to detect the air pressure in the tires; a transmitter configured to be provided on each of the wheels to transmit via wireless signal the air pressure along with identification information inherent to the transmitter; a receiver configured to be provided on a vehicle body to receive the wireless signal; a rotation position calculation unit provided on the vehicle body to correspond to each of the wheels for detecting a rotation position of the wheel; and a wheel position determination unit that accumulates as rotation position data for the wheels, the rotation position of the wheels acquired a plurality of times when a wireless signal is transmitted including a certain identification information; and
that determines wheel position corresponding to the rotation position data having a smallest degree of dispersion from among the rotation position data as the wheel position for the transmitter corresponding to the identification information,the wheel position determination unit converting the rotation position of each of the wheels to a vector with a start point at an origin of a two dimensional plane and an end point at a point on a circumference of a unit circle;
calculates a scalar quantity of an average vector of vectors for the rotation position data as a dispersion characteristic value; and
determines a highest value among the dispersion characteristic values has having the smallest degree of dispersion. - View Dependent Claims (3, 4, 14, 15, 16, 17, 18, 19, 21, 22)
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5. (canceled)
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6. A tire air pressure monitor device that monitors air pressure in tires, the tire air pressure monitor device comprising:
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a tire air pressure sensor configured to be installed on wheels of the tires to detect the air pressure in the tires; a transmitter configured to be provided on each of the wheels to transmit via wireless signal the air pressure along with identification information inherent to the transmitter; a receiver configured to be provided on a vehicle body to receive the wireless signal; a rotation position calculation unit provided on the vehicle body to correspond to each of the wheels for detecting a rotation position of the wheel; a wheel position determination unit that accumulates as rotation position data for the wheels, the rotation position of the wheels acquired a plurality of times when a wireless signal is transmitted including a certain identification information; and
that determines wheel position corresponding to the rotation position data having a smallest degree of dispersion from among the rotation position data as the wheel position for the transmitter corresponding to the identification information; anda wheel speed sensor that outputs a wheel speed pulse that is a proportion of a rotation speed of the wheel, the rotation position calculation unit detecting the rotation position of the wheel from a count value for the wheel speed pulse, the wheel position determination unit accumulating as the rotation position data for the wheels the rotation position of the wheels acquired the plurality of times when the wireless signal is transmitted including a certain sensor ID during a period when the wheels are rotating in an identical direction; and
determines the wheel position corresponding to the rotation position data having the smallest degree of dispersion from among the rotation position data as the wheel position for the transmitter corresponding to the sensor ID,the wheel position determination unit calculating a degree of dispersion among the rotation position data during a plurality of periods when the wheels are rotating in the identical direction up until an accumulated travel time for the vehicle reaches a first predetermined time; and
calculating a final degree of dispersion based on the degree of dispersion for each of the periods. - View Dependent Claims (7, 8)
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9. A tire air pressure monitor device that monitors air pressure in tires, the tire air pressure monitor device comprising:
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a tire air pressure sensor configured to be installed on wheels of the tires to detect the air pressure in the tires; a transmitter configured to be provided on each of the wheels to transmit via wireless signal the air pressure along with identification information inherent to the transmitter; a receiver configured to be provided on a vehicle body to receive the wireless signal; a rotation position calculation unit provided on the vehicle body to correspond to each of the wheels for detecting a rotation position of the wheel; a wheel position determination unit that accumulates as rotation position data for the wheels, the rotation position of the wheels acquired a plurality of times when a wireless signal is transmitted including a certain identification information; and
that determines wheel position corresponding to the rotation position data having a smallest degree of dispersion from among the rotation position data as the wheel position for the transmitter corresponding to the identification information, anda wheel speed sensor that outputs a wheel speed pulse that is a proportion of a rotation speed of the wheel; and the rotation position calculation unit detecting the rotation position of the wheel from a count value for the wheel speed pulse; and the wheel position determination unit further including; a first determination unit that before an accumulated travel time of the vehicle reaches a predetermined accumulated travel time computes a degree of dispersion of wheel position data when a number of data items for the rotation position data is a predetermined number or more;
calculates the degree of dispersion among the wheel position data, and determines the wheel position corresponding to the rotation position data having the smallest degree of dispersion as the wheel position for the transmitter corresponding to a sensor ID; anda second determination unit that when the accumulated travel time of the vehicle reaches the predetermined accumulated travel time, calculates the degree of dispersion among the wheel position data and determines the wheel position corresponding to the rotation position data having the smallest degree of dispersion as the wheel position for the transmitter corresponding to the sensor ID. - View Dependent Claims (10, 11, 12, 13)
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20. (canceled)
Specification