Gear pump

Abstract

Gear pump (1) for pumping liquids, of the type comprising: a stator unit (2), which is equipped with a substantially cylindrical cavity (3) and is designed to generate a magnetic field rotating on the inside of said cavity (3); a substantially tubular, cylindrical bush (4), which is keyed on the inside of the cavity (3) of the stator unit (2); and at least one pumping gear (5, 6) housed in an axially rotatable manner on the inside of the bush (4); one or more longitudinal grooves (12) being present in the zone of contact between the stator unit (2) and the bush (4), said longitudinal grooves extending in the interstitial space between the bush (4) and the stator unit (2) and being designed to conduct an adhesive inside the interstitial space between the bush (4) and the stator unit (2).

1 . A gear pump ( 1 ) for pumping liquids, the gear pump comprising: a stator unit ( 2 ), which defines a substantially cylindrical cavity ( 3 ) and which is cnfigured to generate a magnetic field rotating on an inside of said cavity ( 3 ); a substantially tubular, cylindrical bush ( 4 ), which is keyed on the inside of the cavity ( 3 ) of the stator unit ( 2 ); at least one pumping gear ( 5 ,  6 ) housed in an axially rotatable manner on an inside of the bush ( 4 ); and one or more longitudinal grooves ( 12 ) in a zone of contact between the stator unit ( 2 ) and the bush ( 4 ), said one or more longitudinal grooves extending in an interstitial space between the bush ( 4 ) and the stator unit ( 2 ) and being configured to conduct an adhesive inside the interstitial space between the bush ( 4 ) and the stator unit ( 2 ). 
     
     
         2 . The gear pump according to  claim 1 , wherein ( 1 ) the longitudinal groove or grooves ( 12 ) extends or extend on an inside of the interstitial space between the bush ( 4 ) and the stator unit ( 2 ), substantially over an entire axial length (l) of the zone of contact. 
     
     
         3 . The gear pump according to  claim 1 , wherein the longitudinal groove or grooves ( 12 ) is or are substantially rectilinear. 
     
     
         4 . The gear pump according to  claim 1 , wherein the longitudinal groove or grooves ( 12 ) follows or follow a substantially helical curved trajectory. 
     
     
         5 . The gear pump according to  claim 1 , wherein the zone of contact between the stator unit ( 2 ) and the bush ( 4 ) is provided with a plurality of longitudinal grooves ( 12 ) alongside one another. 
     
     
         6 . The gear pump according to  claim 1 , wherein the stator unit ( 2 ) comprises a plurality of polar cores ( 8 ), which surround said cavity ( 3 ) and are equipped with polar heads ( 9 ) which contribute to delimiting/defining the perimeter of said cavity ( 3 ); the longitudinal groove or grooves ( 12 ) being formed on at least one of said polar heads ( 9 ). 
     
     
         7 . The gear pump according to  claim 1 , wherein the bush ( 4 ) is a cylindrical tubular body made of a plastic material. 
     
     
         8 . The gear pump according to  claim 1 , wherein said at least one pumping gear ( 5 ,  6 ) comprises: a ring gear ( 5 ) with inner toothing, is the ring gear being housed in an axially rotatable manner on the inside of the bush ( 4 ); and a gear wheel ( 6 ), which is fitted in an axially rotatable manner on a support pin ( 13 ) positioned eccentrically on an inside of the ring gear ( 5 ) and meshes on the inner toothing of the ring gear ( 5 ). 
     
     
         9 . A method for assembling a gear pump ( 1 ) for pumping liquids, the gear pump comprising: a stator unit ( 2 ), which defines a substantially cylindrical cavity ( 3 ) and is configured to generate a magnetic field rotating on an inside of said cavity ( 3 ); a substantially tubular, cylindrical bush ( 4 ), which is keyed on the inside of the cavity ( 3 ) of the stator unit ( 2 ); and at least one pumping gear ( 5 ,  6 ) housed in an axially rotatable manner on an inside of the bush ( 4 );
 the method comprising the steps of inserting the bush ( 4 ) into the cavity ( 3 ) of the stator unit ( 2 ), and then injecting an adhesive into one or more longitudinal grooves ( 12 ) extending in an interstitial space between the bush ( 4 ) and the stator unit ( 2 ).   
     
     
         10 . The method for assembling a gear pump according to  claim 9 , wherein the method further comprises the step of inserting said at least one pumping gear ( 5 ,  6 ) into the inside of the bush ( 4 ), before inserting the bush ( 4 ) into the cavity ( 3 ) of the stator unit ( 2 ). 
     
     
         11 . A gear pump ( 1 ) for pumping liquids, the gear pump comprising: a stator unit ( 2 ), which defines a substantially cylindrical cavity ( 3 ) and which is configured to generate a magnetic field rotating on an inside of said cavity ( 3 ); a substantially tubular, cylindrical bush ( 4 ), which is keyed on the inside of the cavity ( 3 ) of the stator unit ( 2 ); at least one pumping gear ( 5 ,  6 ) housed in an axially rotatable manner on an inside of the bush ( 4 ); and one or more longitudinal grooves ( 12 ) in a zone of contact between the stator unit ( 2 ) and the bush ( 4 ), said one or more longitudinal grooves extending in an interstitial space between the bush ( 4 ) and the stator unit ( 2 ) and containing an adhesive fixing the bush to the stator unit. 
     
     
         12 . The gear pump according to  claim 11 , wherein ( 1 ) the longitudinal groove or grooves ( 12 ) extends or extend on an inside of the interstitial space between the bush ( 4 ) and the stator unit ( 2 ), substantially over an entire axial length (l) of the zone of contact. 
     
     
         13 . The gear pump according to  claim 11 , wherein the longitudinal groove or grooves ( 12 ) is or are substantially rectilinear. 
     
     
         14 . The gear pump according to  claim 11 , wherein the longitudinal groove or grooves ( 12 ) follows or follow a substantially helical curved trajectory. 
     
     
         15 . The gear pump according to  claim 11 , wherein the zone of contact between the stator unit ( 2 ) and the bush ( 4 ) is provided with a plurality of longitudinal grooves ( 12 ) alongside one another. 
     
     
         16 . The gear pump according to  claim 11 , wherein the stator unit ( 2 ) comprises a plurality of polar cores ( 8 ), which surround said cavity ( 3 ) and are equipped with polar heads ( 9 ) which contribute to delimiting/defining the perimeter of said cavity ( 3 ); the longitudinal groove or grooves ( 12 ) being formed on at least one of said polar heads ( 9 ). 
     
     
         17 . The gear pump according to  claim 11 , wherein the bush ( 4 ) is a cylindrical tubular body made of a plastic material. 
     
     
         18 . The gear pump according to  claim 11 , wherein said at least one pumping gear ( 5 ,  6 ) comprises: a ring gear ( 5 ) with inner toothing, is the ring gear being housed in an axially rotatable manner on the inside of the bush ( 4 ); and a gear wheel ( 6 ), which is fitted in an axially rotatable manner on a support pin ( 13 ) positioned eccentrically on an inside of the ring gear ( 5 ) and meshes on the inner toothing of the ring gear ( 5 ).