Synchronous electric motor for the operation of a pump and the related motor pump

A motor pump comprising:

• (a) a first pump;
• and
• (b) an electric motor coupled to the first pump, wherein the electric motor includes
• (i) a motor body, a stator and a rotor coupled to an impeller of the first pump, wherein at least one permanent rotor magnet is embedded within the rotor;
• and
• (ii) a cylindrical element that extends towards an inside of the motor body from one of a plurality of outer walls of the motor body so as to divide the inside of the motor body in two cavities, wherein the two cavities include a first cylindrical cavity arranged inside the cylindrical element that is able to house the rotor and a second cavity disposed outside the cylindrical element and able to house the stator;
• and
• (c) a duct placed on the side of said cylindrical element, wherein the duct defines a longitudinal slot of communication between said cylindrical element and the duct, wherein the duct is in communication with said first pump so that the fluid pumped by said first pump may enter into the duct and lubricate, or cool, or lubricate and cool, a contact area between said rotor and said cylindrical element,
• wherein the cylindrical element has a first open end, opposite to a second end, positioned at one of the plurality of outer walls of the motor body so that the first cylindrical cavity is open to the outside so as to insert the rotor inside the cylindrical element, wherein the rotor, for at least part of the length of the rotor, has a circular cross section essentially corresponding to an inner section of the cylindrical element so that the rotor is in contact with the cylindrical element and so there is friction between the rotor and the cylindrical element when the rotor rotates, and wherein the rotor is shaftless and axially and directly coupled to the impeller of the first pump.