Sensor for a pneumatic tyre

摘要

A sensor (1) for detecting rotations of a pneumatic tyre on a vehicle comprising two spaced apart mounting points for attachment to the radially inner surface of the tyre tread region, a contact member between the mounting points for contacting the inner surface of the tyre between the two mounting points and signal producing means adapted to produce a signal when the contact member is moved radially of the tyre relative to the two mounting points wherein damping means are provided to so that a signal is generated when the movement occurs rapidly but slow movement generates no signal so that on rotation of the tyre on a vehicle a signal is produced each time the tread region to which the sensor (1) is attached becomes change in radius at the contact patch of the tyre but when the tread radius changes slowly such as when there is a pressure change in the tyre and the movement is slow no signal is produced. <IMAGE>