Patent ID: 7145446

Claim:
A transponder for a tire condition monitoring apparatus that detects condition of a tire and wirelessly transmits data representing the detected condition in response to radio waves having a field intensity equal to or greater than a predetermined level: wherein the transponder is provided in a tire valve attached to a wheel upon which the tire is mounted, such that the transponder is embedded in the tire; wherein the transponder includes: a condition detecting device for detecting a condition of the tire; a coil antenna, which is induced by radio waves having a field intensity equal to or greater than a predetermined level to generate electricity; and an annular casing mounted on the tire valve, the annular casing comprising an upper casing portion and a lower casing portion that are connected with each other along a plane intersecting an axis of the casing, the annular casing having an accommodating portion that accommodates the coil antenna and a projecting portion projecting into the tire from the accommodating portion, the projecting portion accommodating the condition detecting device, wherein the accommodating portion is formed at an upper periphery of the casing to extend across the upper casing portion and the lower casing portion, and wherein the projecting portion projects from the lower casing portion; wherein, based on the electricity induced by the coil antenna, the transponder detects condition of the tire with the condition detecting device and wirelessly transmits data representing the detected condition.