Patent ID: 7045922

Claim:
A permanent-magnet synchronous electric motor with isolated rotor for circulation pumps of heating and/or conditioning systems, comprising: a motor casing, a stator in said motor casing with associated coils; a permanent-magnet rotor mounted in a housing isolated from the stator; a shaft integral with the rotor, the shaft being mounted inside a tube having a tapered open end; and at least one bearing means supporting said shaft and being fixed to said housing; at least one of said at least one bearing means comprising: a bush rotatively engaged by one end of the shaft; a sleeve piece keyed onto the bush and fixedly inserted by a screw-threaded connection to the tapered open end of the tube at one end of the housing; and a cap having a first portion removably inserted into the sleeve piece and a second portion screwly engaged in a threaded seat of the casing, wherein the sleeve piece is formed of an elastomeric material and has a tapered inner portion, and wherein the first portion of the cap is inserted into the tapered inner portion of the sleeve such that the sleeve piece is caused to expand and is pressed tightly between the cap and the tapered end of the tube.