Electric motor for use in a dental, dental-medical or dental-technical handpiece and stator therefor

An autoclavable dental handpiece comprising:

• an elongate tubular member having a proximal end having a first coupling member adapted to connect to a second coupling member supplying electrical power and flow of fluid to the handpiece, and a distal end having a tool receiver for detachably holding a dental tool in the handpiece;
• an electric motor in the tubular member comprising a stator having stator windings, and a rotor comprising a central axial shaft and permanent magnets carried on the shaft;
• the stator being positioned in a chamber in the tubular member and being sealed within a sheathing having an inner sleeve and an outer sleeve, the outer sleeve embedding the inner sleeve with functionally relevant components of the stator, to protect the stator windings against exposure to contaminants;
• electrical leads extending from the first coupling member at the proximal end of the tubular member into the chamber to conduct electrical power to the stator windings;
• a conduit having a web configured to form a seal against at least one of the inner sleeve and the outer sleeve, wherein at least one of the electrical leads passes through the conduit;
• bearings mounting the rotor for rotation within and relative to the stator and securing the rotor against axial movement within the tubular member;
• and
• a drive transmission toward the distal end of the tubular member mounted for rotation within the tubular member and connecting an end of the rotor to the tool receiver for rotating the tool receiver when the motor is activated,
• wherein the inner sleeve and the outer sleeve are adjoined to, and interlocked with, one another with at least one circumferential web on the inner sleeve and a corresponding configuration on the outer sleeve.