Hydraulic axial piston pump having a floating rotatory drum

Abstract

The invention relates to a pump comprising: a housing ( 1 ); a drum ( 2 ) having cylinders in which pistons ( 3 ) are mounted, which pistons are supported by supporting shoes ( 32 ) on a fixed inclined plate ( 4 ); and first and second fluid-distributing plates ( 5 a, 5 b ) having openings ( 51, 52 ) for establishing in an alternating manner the connection between first mouths ( 23 ) of the cylinders ( 22 ) and a first inlet ( 11 ) and first outlet ( 12 ) of primary liquid, and between second mouths ( 24 ) and a second inlet ( 13 ) and second outlet ( 14 ) of the secondary liquid. The pump comprises first and second strips ( 6 a, 6 b ) arranged between the drum ( 2 ) and the distributing plates ( 5 a, 5 b ), said strips being movable in a longitudinal direction and allowing the drum to tilt to a certain extent, forming a sealed closure between the ends of the drum ( 2 ) and the distributing plates ( 5 a, 5 b ).

1 . A hydraulic axial piston pump having a floating rotatory drum, comprising:
 a housing ( 1 ) provided with: a first inlet ( 11 ) for the intake of a primary liquid; a first outlet ( 12 ) for the delivery of said primary liquid at a high pressure; a second inlet ( 13 ) for the intake of a secondary liquid at a pressure that is lower than the delivery pressure of the primary liquid and a second outlet ( 14 ) for the delivery of said secondary liquid;   a drum ( 2 ) provided with a drive shaft ( 21 ) and with a plurality of cylinders ( 22 ) arranged in circular fashion around the geometric axis of said drum ( 2 ) and communicated at its ends with first inlet and outlet mouths ( 23 ) of the primary liquid and with second inlet and outlet mouths ( 24 ) of the secondary liquid, said first and second mouths ( 23 ,  24 ) being defined at a first end and at a second end of the drum ( 2 );   pistons ( 3 ) mounted in the respective cylinders ( 22 ) and being prolonged in rods ( 31 ) projecting through one end of the drum ( 2 ) and ending in supporting shoes ( 32 ) on a fixed inclined plate ( 4 );   a first fluid-distributing plate ( 5   a ) and a second fluid-distributing plate ( 5   b ), facing opposite ends of the drum ( 2 ) and provided with openings ( 51 ,  52 ) suitably distributed for establishing in an alternating manner, during rotation of the drum ( 2 ), the connection between first mouths ( 23 ) of the cylinders ( 22 ) and the first inlet ( 11 ) and first outlet ( 12 ) of primary liquid of the housing ( 1 ), and the connection between second mouths ( 24 ) of the cylinders ( 22 ) and the second inlet ( 13 ) and second outlet ( 14 ) of the secondary liquid, said connections being established such that it is synchronized with the direction of movement of the pistons ( 3 ) inside the cylinders ( 22 );   characterized in that:   first and second strips ( 6   a,    6   b ) rotating together with the drum ( 2 ) are mounted with certain clearance in the axial direction between a first end of the rotatory drum ( 2 ) and the first distributing plate ( 5   a ), and between a second end of the drum ( 2 ) and the second distributing plate ( 5   b ); said first and second strips ( 6   a,    6   b ) having openings facing the first and second mouths ( 23 ,  24 ) of the drum and coupling means suitable for allowing a movement of the first and second strips ( 6   a,    6   b ) in the axial direction with respect to the drum ( 2 ) and the head-on actuation of said strips ( 6   a,    6   b ) against the respective distributing plates ( 5   a,    5   b ), said strips ( 6   a,    6   b ) forming a sealed closure between the ends of the drum ( 2 ) and the respective distributing plates ( 5   a,    5   b ).   
     
     
         2 . The pump according to  claim 1 , characterized in that the surfaces of the drum ( 2 ) intended for coming into contact with the primary and secondary liquids are suitably arranged and sized so that the resultant of the forces generated by the pressure of the primary and secondary liquids on the drum ( 2 ) have a zero component in the axial direction. 
     
     
         3 . The pump according to  claim 1 , characterized in that the openings of the strips ( 6   a,    6   b ) are peripherally prolonged in sleeves ( 61 ,  62 ) suitable for being housed in the first and second mouths ( 23 ,  24 ) of the drum ( 2 ) with the interposition of sealing elements ( 7 ), allowing a certain tilt or misalignment of the drum, and for receiving, by action of the pressure of the primary and secondary liquids, a thrust that axially moves said strips ( 6   a,    6   b ) against the distributing plates ( 5   a,    5   b ). 
     
     
         4 . The pump according to  claim 1 , characterized in that it comprises springs ( 8 ) oriented in the axial direction, suitable to assure certain pressure of said strips ( 6   a,    6   b ) against the respective distributing plates ( 5   a,    5   b ), between a first end of the drum ( 2 ) and the first strip ( 6   a ), and between a second end of the drum ( 2 ) and the second strip ( 6   b ). 
     
     
         5 . The pump according to  claim 2 , characterized in that the first mouths ( 23 ) of the drum ( 2 ) are axially aligned with the cylinders ( 22 ) of the drum and have diameters coinciding with those of said cylinders for preventing the pressure of the primary liquid from causing a thrusting force on the drum ( 2 ) in the axial direction. 
     
     
         6 . The pump according to  claim 1 , characterized in that the second mouths ( 24 ) of the drum ( 2 ) are oriented axially and connected to the cylinders ( 22 ) by means of intermediate conduits ( 25 ), the second mouths ( 24 ) having a section that is equal to an end surface ( 26 ) of the corresponding cylinder ( 22 ) exposed to the pressure of the secondary liquid, such that the resultant of the set of forces generated by the pressure of the secondary liquid on the drum ( 2 ) has a zero component in the axial direction.