Tire Pressure Measuring System and Tire Pressure Measuring Device
First Claim
1. A tire pressure measuring system in which a control unit mounted on a vehicle body is connected by radio to a sensor unit mounted on a tire of the vehicle body, for transmitting air pressure inside the tire, measured by the sensor unit, to the control unit, whereinthe control unit comprisesan electromagnetic field generation circuit for generating a transmission electromagnetic field varying at a predetermined transmission frequency, anda data receiving circuit for detecting transmission data from the sensor unit, based on variation of the transmission electromagnetic field, the variation caused due to the sensor unit,the sensor unit comprisesan antenna for receiving the transmission electromagnetic field, and through interaction with the transmission electromagnetic field, affecting the transmission electromagnetic field such that the transmission electromagnetic field varies, to thereby communicate with the control unit, anda data transmission circuit for changing an antenna current flowing in the antenna to thereby cause the transmission electromagnetic field to vary, and alternately transmitting a plurality kinds of transmission data, including the air pressure, andthe data transmission circuit detects a rotation cycle of the tire, based on change of strength with which the transmission electromagnetic field is received, and carries out a transmission operation while switching the kinds of transmission data in conjunction with the rotation cycle.
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Accused Products
Abstract
A tire pressure measuring system (TPMS) for transmitting pressure information from a tire to a vehicle body has a complicated structure when a plurality kinds of transmission data exist. A sensor unit receives a transmission electromagnetic field from a sensor control unit, and rectify-detects the received field. The counter of the sensor unit determines a rotation cycle of a tire, based on the signal obtained by the rectification detection, then switches the switch in conjunction with the rotation cycle, and sequentially sends the plurality of transmission data items for every tire rotation.
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Citations
12 Claims
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1. A tire pressure measuring system in which a control unit mounted on a vehicle body is connected by radio to a sensor unit mounted on a tire of the vehicle body, for transmitting air pressure inside the tire, measured by the sensor unit, to the control unit, wherein
the control unit comprises an electromagnetic field generation circuit for generating a transmission electromagnetic field varying at a predetermined transmission frequency, and a data receiving circuit for detecting transmission data from the sensor unit, based on variation of the transmission electromagnetic field, the variation caused due to the sensor unit, the sensor unit comprises an antenna for receiving the transmission electromagnetic field, and through interaction with the transmission electromagnetic field, affecting the transmission electromagnetic field such that the transmission electromagnetic field varies, to thereby communicate with the control unit, and a data transmission circuit for changing an antenna current flowing in the antenna to thereby cause the transmission electromagnetic field to vary, and alternately transmitting a plurality kinds of transmission data, including the air pressure, and the data transmission circuit detects a rotation cycle of the tire, based on change of strength with which the transmission electromagnetic field is received, and carries out a transmission operation while switching the kinds of transmission data in conjunction with the rotation cycle.
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5. A tire pressure measuring device, comprising:
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an antenna for interaction with a supply electromagnetic field given from outside to thereby cause the supply electromagnetic field to change in amplitude, and a data transmission circuit for changing an antenna current flowing in the antenna to thereby change the amplitude of the supply electromagnetic field, and alternately transmitting to the outside a plurality kinds of transmission data including air pressure, wherein the data transmission circuit detects a rotation cycle of a tire, based on change of strength with which to receive the supply electromagnetic field, and carries out a transmission operation while switching the kinds of transmission data in conjunction with the rotation cycle. - View Dependent Claims (6, 7, 8, 11, 12)
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Specification