A brushless motor

A brushless motor 1 comprising a stator assembly (10, fig 2), a rotor assembly 12, and a frame (14, fig 1) to house the stator and rotor. The rotor comprises a shaft 70, first 74 and second 76 bearings attached to the shaft, a permanent magnet 72 attached to the shaft between the first and second bearings, and an impeller 84, where the first bearing is located further away from the impeller than the second bearing, and an o-ring 92 mounted between the first bearing and the frame. The o-ring may be mounted between the first bearing and the frame such that the o-ring is able to move axially relative to the frame without deformation of the o-ring such that the o-ring is substantially uncompressed and where the o-ring comprises a circular cross-sectional shape when mounted between the bearing and frame. The o-ring may comprise a radial stiffness in the region of 1.0x106 N/m to 4.0x106 N/m and may comprise a material having a Shore A hardness in the region of 65-90. The o-ring may comprise a thermal conductivity of at least 3W/mK. The contact surfaces of the first bearing and frame may be smooth to allow the o-ring to move axially over the surface. The motor may be used within a vacuum cleaner.