Power generator

摘要

A telemetry unit ( 100 ) is provided for mounting inside a pneumatic tyre. The unit ( 100 ) includes a piezoelectric power generator for supplying power to the unit ( 100 ). A piezoelectric element ( 114 ) is supported in a housing ( 112 ) with an actuator 136 arranged for contact with the element ( 114 ), to deflect the element ( 114 ) in response to external forces acting on the actuator ( 136 ) during rotation of the tyre. For every rotation of the tyre, cyclic pulses of electrical charge are generated by the deflection of the element ( 114 ). The charge is stored and utilised under a power consumption protocol to operate pressure and temperature sensors and to transmit data from the unit ( 100 ). The telemetry circuitry is mounted for movement with the actuator ( 136 ) and therefore contributes to the actuating mass acting on the element ( 114 ).