摘要 |
A device (10) is disclosed for providing air to a tyre which is mounted on a wheel rim which itself is free to rotate about a fixed, that is, non-rotatable axle 22. The device includes a pump (50, 52, 54, 62) which in use rotates with the tyre and which is configured to provide, when activated, air under pressure to the tyre. There is a pump drive system for activating the pump. The pump drive system comprising a piston rod (56) which is connected to and rotates with the tyre and a body (40) which rotates in unison with the rod (56) whilst the pump is inactive. An electric motor (68) rotates the body (40) with respect to the rod (56) to activate the pump and provide air to the tyre. Rotation of the body (40) is superimposed on rotation of the pump with the tyre. The device also includes a stator component (26) and coils (30) and magnets (32) for generating, by electrical induction, power for driving the motor using the relative rotation between the second part and the stator component (26). |