| 摘要 |
<p>A rotor shaft 7 extends through the stator assembly 4 mounting a permanent magnet rotor 8 by a ball-spline 11, the rotor being rotatable with respect to the stator assembly 4 and movable axially with respect to the shaft 7 so as to provide an adjustable air gap. An air gap adjusting plate 12 is mounted for relative rotation to the rotor by bearing 31, axial movement of the plate being transmitted to the rotor via the bearing. Gear 16, sector 14 and cams 20 move the plate 12 which displaces the rotor 8 and its associated ball-spline axially along the shaft 7 whilst the shaft is rotating so as to adjust the air gap between the rotor 8 and stator assembly 4. Alternatively the adjustment means may comprise a electromagnetic element (Fig 11 not shown) in the form of a coil located in the ball-spline (or the shaft) which acts on the shaft (or the ball-spline). Hydraulic, screw-thread or a weighted element variator actuation is also disclosed. A second rotor defining a further air gap may be mounted on the shaft and this air gap may be varied independently or in concert with the first air gap.</p> |
