| 摘要 |
PROBLEM TO BE SOLVED: To solve problem that the sending property of a radio wave radiated from an antenna is deteriorated under the influence of potential change of a rim, in a tire internal pressure alarm device attached to the rim, detecting the internal pressure of a tire, and sending the detected signal from the antenna to a receiver in a vehicular body side. SOLUTION: In an attaching position to a rim, a platy battery and an electronic substrate are arranged to be generally orthogonal to a cross-section on the cross-section passing a rim axis, and in two layers. The platy battery is disposed in a side close to a well portion bottom surface of the rim. |
