received by the International Bureau on 17 May 2016 (17.05.2016)

Electric pump comprising a drive shaft (8) having a longitudinal axis (A), a chamber (6') containing air, an electric motor member (6), comprising a rotor (62) joined to said drive shaft (8) and a stator (61 ) fixed about said rotor (62), said rotor (62) and said stator (61 ) being arranged inside said chamber (6') containing air, said electric motor member (6) being configured to operate in rotation said drive shaft (8) about said longitudinal axis (A), at least one pump stage (4) comprising an impeller (9) keyed to said drive shaft (8) and a diffuser member (71 ) fixed relatively to said impeller (9), to pump a pumping liquid from a suction part (2) to a delivery part (3) of said pump, a cooling device (10) to cool said motor member (6),

characterized in that said cooling device (10) comprises a containment body (1 1 ) for a cooling liquid and a conveying circuit (23, 24, 25, 26) predisposed to produce the forced circulation of said cooling liquid contained in said containment body (1 1 ), said conveying circuit (23, 24, 25, 26) comprising at least one discharge opening (26) being in communication with said chamber (6') containing air, and directly crossing both said rotor (62) and said stator (61 ) of said motor member (6), to perform the emission of said cooling liquid in a sprayed state by virtue of an interaction between said cooling liquid and said air surrounding said motor member (6), directly on said rotor (62) and on said stator (61 ) of said motor member (6) contained in said chamber (6') containing air.

Electric pump according to claim 1 , characterized in that said containment body (1 1) comprises a conveying portion (17) arranged about said longitudinal axis (A), a conveying member (12) being disposed about said conveying portion (17), and fixed to said drive shaft (8), so as to determine a relative rotation motion between said conveying portion (17) and said conveying member (12) upon activation of said drive shaft (8), a passage zone (23) for said cooling liquid being defined between said conveying portion (17) and said conveying member (12), so as to convey said cooling liquid through said conveying circuit (23, 24, 25, 26) under said relative rotation motion.

Electric pump according to claim 2, characterized in that said discharge opening (26) is arranged in communication with a front side, in use, of said motor member (6) and is obtained on said drive shaft (8), said drive shaft (8) also shaping at least one forward path channel (24) for said cooling liquid, arranged in communication with said discharge opening (26) and with said passage zone (23), so as to comprise a portion (30) of said conveying circuit (23, 24, 25, 26) for said forced circulation of said cooling liquid.

Electric pump according to claim 3, characterized in that said forward path channel (24) is axial and internal to said drive shaft (8).

Electric pump according to claim 4, characterized in that said passage zone (23) shapes a helical portion for said cooling liquid around said longitudinal axis (A).

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6. Electric pump according to claim 5, characterized in that said conveying portion shapes a central sleeve (17) arranged around said longitudinal axis (A), said conveying member (12) being coaxially disposed around said central sleeve (17).

7. Electric pump according to claim 6, characterized in that said containment body (1 1 ) comprises a side wall (16) of containment, a plurality of fins (20) being arranged between said side wall (16) and said central sleeve (17) to increase the surface for the heat exchange with said cooling liquid inside said containment body (1 1 ).

8. Electric pump according to claim 6 or 7, characterized in that said passage zone (23) between said conveying member (12) and said central sleeve (17) of said containment body (1 1 ) comprises at least one helical groove, through which said cooling liquid is predisposed to go from said containment body (1 1 ) to said drive shaft (8).

9. Electric pump according to claim 3, characterized in that said conveying member (12) is made in the shape of a bell.

10. Electric pump according to claim 3, characterized in that said drive shaft (8) comprises at least one transverse passage (25) of connection between said forward path channel (24) and said passage zone (23), to allow said forced circulation of said cooling liquid.

1 1. Electric pump according to one of the previous claims, characterized in that said containment body (1 1 ) is interposed between said pump stage (4) and said motor member (6).

12. Electric pump according to one of the previous claims, characterized in that said containment body (1 1 ) is constrained to a fixed portion of said electric pump.

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