Tire position determination system

Patent metadata

Field	Value
Publication number	US-2016288595-A1
Application number	US-201415035028-A
Country	US
Kind code	A1
Filing date	Nov 12, 2014
Priority date	Nov 15, 2013
Publication date	Oct 6, 2016
Grant date	—

Abstract

A tire position determination system is provided with: a plurality of tire air pressure transmitters each capable of transmitting a first radio signal including air pressure data and a tire ID; a plurality of axle rotation detection units each generating axle rotation information; and a receiver mounted to a vehicle body and capable of receiving the first radio signal. Each of the plurality of tire air pressure transmitters includes a specific position detection unit capable of detecting the arrival of the tire air pressure transmitter at a specific position on a trajectory of rotation of the tire, and a transmission control unit that, based on a result of detection, generates a second radio signal including data indicating the arrival of the tire air pressure transmitter at the specific position on the trajectory of rotation of the tire and the ID. The receiver includes a position determination unit that determines a tire position of the plurality of tires based on the second radio signal.

First claim

1 . A tire position determination system comprising:
tire pressure transmitters respectively coupled to tires, wherein each of the tire pressure transmitters is capable of transmitting a first radio wave signal that includes pressure data and a tire ID; axle rotation detectors respectively arranged on axles, wherein each of the axle rotation detectors detects rotation of a corresponding one of the axles and generates axle rotation information; and a receiver arranged on a vehicle body, wherein the receiver is capable of receiving the first radio wave signal transmitted from each of the tire pressure transmitters, wherein each of the tire pressure transmitters includes:
a specific position detector that detects that the tire pressure transmitter has reached a specific position on a rotation path of the tire; and
a transmission controller that generates a second radio wave signal, which includes an ID and data indicating that the tire pressure transmitter has reached a specific position on the rotation path of the tire, based on a detection result of the specific position detector and transmits the second radio wave signal from the tire pressure transmitter, and
the receiver includes:
an axle rotation information acquisition unit that acquires the axle rotation information from each of the axle rotation detectors whenever the receiver receives the second radio wave signal; and
a position determination unit that calculates a distribution of the axle rotation information for each of the IDs by collecting statistics of the axle rotation information for each of the IDs and determines tire positions of the tires by specifying an ID of a tire that rotates in synchronism with the axle rotation information of each of the axles based on the distribution.

2 . The tire position determination system according to claim 1 , wherein
in an operation of the tire pressure transmitter, a relatively short first time period, during which transmission of a radio wave signal is allowed, and a second time period, during which transmission of a radio wave signal is temporarily stopped, are alternately repeated, and the transmission controller transmits the second radio wave signal a number of times in the first time period.

3 . The tire position determination system according to claim 1 , wherein the position determination unit performs absolute evaluation, which determines validity of the distribution using the axle rotation information of each of the axles, and relative evaluation, which determines validity of the distribution using the axle rotation information of the axles, to determine a tire position based on a result of the absolute evaluation and a result of the relative evaluation.

4 . The tire position determination system according to claim 1 , wherein the position determination unit performs relative evaluation that determines validity of the distribution using variance of the axle rotation information of the axles to determine a tire position based on a result of the relative evaluation.

5 . The tire position determination system according to claim 1 , wherein
the receiver includes
a traveling determination unit that determines a traveling state, and
a weighting unit that weights the second radio wave signal received by the receiver based on a determination result of the traveling determination unit; and
the position determination unit calculates a distribution of the axle rotation information for each of the IDs by collecting statistics on the axle rotation information that reflects the weighting for each of the IDs and determines tire positions of the tires based on the distribution.

6 . The tire position determination system according to claim 5 , wherein
the traveling determination unit is capable of determining a speed of a vehicle, and the weighting unit weights the second radio wave signal based on speed dependency.

7 . The tire position determination system according to claim 5 , wherein
the traveling determination unit is capable of determining acceleration and deceleration of a vehicle, and the weighting unit weights the second radio wave signal based on acceleration/deceleration dependency.

8 . The tire position determination system according to claim 1 , wherein when a tire position of a tire of a specific ID is not specified, leaving candidate tires, and when a tire position of a tire of another ID is specified, the position determination unit deletes the specified tire from the candidate tires and narrows down or specifies a correct tire.

9 . The tire position determination system according to claim 3 , wherein the position determination unit statistically determines variance of the axle rotation information of the axles as the relative evaluation to determine tire positions of the tires.

10 . The tire position determination system according to claim 3 , wherein the position determination unit relatively evaluates variance of the axle rotation information of the axles and ranks the axles to determine tire positions of the tires.

11 . The tire position determination system according to claim 2 , wherein
the receiver includes an information storage that holds one or more pieces of specific position information indicating a time at which the tire pressure transmitter reached a specific position on a rotation path of the tire, the transmission controller transmits the second radio wave signal including an ID and the one or more pieces of specific position information held in the second time period, and the position determination unit calculates, based on the specific position information that is received by the receiver, axle rotation information at a point of time when the tire pressure transmitter previously reached a specific position and determines tire positions of the tires using the calculated axle rotation information.

Assignees

• Tokai Rika Co Ltd

Inventors

• Watanabe Naoki
• Tsuchikawa Yuta
• Kumagai Katsuhide
• Matsushita Masahiro

Classifications

• B60C23/04

  mounted on the wheel or tyre · CPC title

• G01L17/00

  Devices or apparatus for measuring tyre pressure or the pressure in other inflated bodies · CPC title

• B60C23/02

  Signalling devices actuated by tyre pressure {(hand-held tyre pressure gauges G01L17/00)} · CPC title

• G08C19/00

  Electric signal transmission systems (G08C17/00 takes precedence) · CPC title

• G08C17/00

  Arrangements for transmitting signals characterised by the use of a wireless electrical link · CPC title