Uniaxial Eccentric Screw Pump

Abstract

An object of the present invention is to provide a uniaxial eccentric screw pump capable of transferring and filling a fluid while realizing high flow rate accuracy, low pulsation, and long life. A uniaxial eccentric screw pump ( 11 ) in which an external screw type rotor ( 12 ) is fittingly inserted in an inner hole ( 13 a ) of an internal screw type stator ( 13 ), the rotor ( 12 ) and the stator ( 13 ) are separately, rotatably supported, and a rotation central axis of the rotor ( 12 ) and a rotation central axis of the stator ( 13 ) are spaced apart from each other is configured such that the rotor ( 12 ) and the stator ( 13 ) are separately rotated by a rotor driving portion ( 27 ) and a stator driving portion ( 19 ), respectively, and the rotor ( 12 ) and the stator ( 13 ) are rotated with the rotor ( 12 ) and the stator ( 13 ) not contacting each other.

1 . A uniaxial eccentric screw pump in which: an external screw type rotor is inserted in an inner hole of an internal screw type stator; the rotor and the stator are separately, rotatably supported; and a rotation central axis of the rotor and a rotation central axis of the stator are arranged to be spaced apart from each other, wherein
 the rotor and the stator are separately rotated.   
   
   
       2 . The uniaxial eccentric screw pump according to  claim 1 , wherein:
 a geometric center axis of the rotor and the rotational center axis of the rotor coincide with each other; and   a geometric center axis of the inner hole of the stator and the rotational center axis of the stator coincide with each other.   
   
   
       3 . The uniaxial eccentric screw pump according to  claim 1 , wherein:
 the rotor is rotatably supported by a driving shaft provided at one end of the rotor, and the driving shaft is rotated by a rotor driving portion;   a stator driving portion is provided with respect to an outer peripheral surface of the stator, and the stator is rotated by the stator driving portion; and   the stator is hermetically stored in a pump casing, and the pump casing includes a first opening communicated with one opening of the inner hole of the stator and a second opening communicated with another opening of the inner hole of the stator.   
   
   
       4 . The uniaxial eccentric screw pump according to  claim 1 , further comprising a magnetic pole type power transmission structure configured to transfer to the rotor a rotational force for causing the rotor to rotate, wherein
 the magnetic pole type power transmission structure includes: a driving magnetic pole portion configured to generate a plurality of driving magnetic poles; a driven magnetic pole portion configured to generate a plurality of driven magnetic poles; and a dividing wall portion configured to seal the driving magnetic pole portion and the driven magnetic pole portion, the plurality of driving magnetic poles are arranged in a circumferential direction of the driving magnetic pole portion, the plurality of driven magnetic poles are arranged in a circumferential direction of the driven magnetic pole portion, and the driven magnetic pole portion rotates by rotation of the plurality of driving magnetic poles.   
   
   
       5 . The uniaxial eccentric screw pump according to  claim 4 , wherein: the plurality of driving magnetic poles and the plurality of driven magnetic poles are generated by magnets arranged such that the north poles and south poles are arranged in alternation; and the driving magnetic pole portion is rotated by the rotor driving portion. 
   
   
       6 . The uniaxial eccentric screw pump according to  claim 4 , wherein the plurality of driving magnetic poles are rotating magnetic fields generated by fixed winding wires, and the plurality of driven magnetic poles are generated by magnets arranged such that that the north poles and south poles are arranged in alternation. 
   
   
       7 . The uniaxial eccentric screw pump according to  claim 1 , wherein the rotor driving portion causes the rotor to rotate and the stator driving portion causes the stator to rotate with the rotor and the stator not contacting each other. 
   
   
       8 . The uniaxial eccentric screw pump according to  claim 1 , wherein:
 the stator has a double thread internal screw type inner hole or a triple thread internal screw type inner hole, and a cross-sectional shape of the inner hole is an elliptical shape or a substantially triangle shape each of whose three corners is a circular-arc shape;   the rotor is a single thread external screw type or a double thread external screw type, and a cross-sectional shape of the rotor is a circular shape or a substantially oval shape;   a ratio of a pitch of the rotor to a pitch of the inner hole is 1 to 2 or 2 to 3; and   a ratio of a rotating speed of the rotor to a rotating speed of the stator is 2 to 1 or 3 to 2.   
   
   
       9 . The uniaxial eccentric screw pump according to  claim 1 , wherein the stator is made of engineering plastic, and the rotor is made of a metal. 
   
   
       10 . The uniaxial eccentric screw pump according to  claim 1 , wherein one or both of the rotor and the stator is rotatably supported by a magnetically-levitated bearing, and one or both of the rotor and the stator is rotatably supported by a magnetic noncontact thrust bearing. 
   
   
       11 . The uniaxial eccentric screw pump according to  claim 1 , wherein one or both of the rotor and the stator is rotatably supported by a magnetic noncontact bearing capable of receiving both a radial load and a thrust load. 
   
   
       12 . A uniaxial eccentric screw pump in which: an external screw type rotor is inserted in an inner hole of an internal screw type stator; the rotor and the stator are separately, rotatably supported; and a rotation central axis of the rotor and a rotation central axis of the stator are arranged to be spaced apart from each other,
 the uniaxial eccentric screw pump comprising a rotor driving portion and a stator driving portion configured to respectively cause the rotor and the stator to rotate with the rotor and the stator not contacting each other.