| 摘要 |
A motor, suitable for a power tool, has stator pole pieces 308 (fig.3) and return path pieces 310 (fig.3) moulded from compressed, insulated iron powder. The pole pieces can be formed in one operation to tighter tolerances than conventional laminated stators. The use of insulated iron powder also results in low eddy current losses. The specification discloses the use of 'sleeves' 900 (figs. 9-12 and 18) and wrapping pieces 1300 (figs. 13-16) which, during manufacture, are fitted to pre-formed field coils in lieu of encapsulation. The sleeving or wrapping that is fitted to the coils acts as a slot liner when the coil is fitted to the stator core. Adhesive strips may also be used. Also disclosed are details of winding construction and insulation, which may include elastomeric encapsulation. The stator windings may extend beyond the tips of the pole pieces. The motor achieves a higher output power with a smaller diameter than a conventional motor. |
