| 摘要 |
PURPOSE:To improve the waterproofing and vibration damping properties of a transmitter incorporated in a tire pressure warning device and, at the same time, to reduce the size and weight of the transmitter. CONSTITUTION:This tire pressure warning device is provided with an antenna on the opposite side of a transmitter, the resonance frequency of which electrically changes in accordance with the output of a pressure sensor, and, by transmitting a short pulse signal to the antenna, outputs an alarm by discriminating the frequency of a resonance signal from the antenna. A coil and capacitor incorporated in the transmitter are covered with a plastic cap 22 and a metallic socket 23 joined with a coil 21 and metallic protective tube 25 for protecting the wires 24 of capacitor is joined with the plastic cap by caulking. Then the space in the cap 22 is filled up with a plastic molded body 26. Therefore, a highly reliable transmitter can be manufactured at a low cost, because the transmitter can be constituted to such a simple and solid structure. |
