Tube pump

Abstract

A tube pump capable that prevents and minimizes torque variation in a drive motor regardless of the rotation direction of a rotor unit includes a casing in which a liquid-flowing tube is arranged; a drive motor provided with a driving shaft rotatable in forward and reverse directions; a rotor body; roller holders supported on the rotor body to swing with respect to the rotor body; pressing rollers rotatably supported on the roller holders to press the tube against an inner circumferential wall surface of the casing; and biasing units biasing the roller holders, when swung, to be returned to a pre-swing position. The roller holders are configured to swing with respect to the rotor body in a direction opposite to a rotation direction of the rotor body.

1 . A tube pump, comprising:
 a casing including an arc-shaped inner circumferential wall surface along which a liquid-flowing tube is arranged;   a drive motor provided with a driving shaft rotatable in forward and reverse directions;   a rotor body arranged in a center position of the arc-shaped inner circumferential wall surface to rotate together with the driving shaft;   roller holders supported on the rotor body to swing with respect to the rotor body and arranged to move both toward and away from the driving shaft on a plane that is perpendicular or substantially perpendicular to the driving shaft;   pressing rollers rotatably supported on the roller holders to press the tube against the inner circumferential wall surface; and   biasing units interposed between the rotor body and the roller holders to bias the roller holders away from the driving shaft and to bias the roller holders, when swung, to be returned to a pre-swing position, the roller holders being configured to swing with respect to the rotor body in a direction opposite to a rotation direction of the rotor body.   
     
     
         2 . The tube pump of  claim 1 , wherein the rotor body includes engagement projection portions extending in an extension direction of the driving shaft and engaging with the roller holders, the engagement projection portions being arranged in opposite side areas of the rotor body along a direction that is perpendicular or substantially perpendicular to the extension direction of the driving shaft and the biasing direction of the biasing units, each of the engagement projection portions including a metal shaft portion fixed to the rotor body and a resin or metal collar portion rotatably supported on the shaft portion, each of the roller holders including an engagement recess portion extending in the extension direction of the driving shaft and engaging with the collar portion. 
     
     
         3 . The tube pump of  claim 1 , wherein the rotor body includes engagement projection portions extending in an extension direction of the driving shaft and slidably engaging with the roller holders, the engagement projection portions arranged in opposite side areas of the rotor body along the direction that is perpendicular or substantially perpendicular to the extension direction of the driving shaft and the biasing direction of the biasing units, the roller holders including engagement recess portions extending in the extension direction of the driving shaft and slidably engaging with the engagement projection portions. 
     
     
         4 . The tube pump of  claim 1 , wherein the biasing units includes a leaf spring defined by a substantial sleeve-shaped configuration including a pair of transverse plate portions extending parallel or substantially parallel to a biasing direction of the biasing units and a pair of longitudinal plate portions extending in a direction perpendicular or substantially perpendicular to the transverse plate portions to interconnect opposite end sections of the transverse plate portions, the transverse plate portions fixed to the rotor body, the longitudinal plate portions fixed to the roller holders. 
     
     
         5 . The tube pump of  claim 1 , wherein the biasing units have a bellows configuration defined by resin plates having a predetermined elasticity to expand and contract in a biasing direction, the rotor body being made of the resin and integrally fixed to the biasing units at base sections of the biasing units, the roller holders being made of the resin and integrally fixed to the biasing units at end sections of the biasing units in the biasing direction. 
     
     
         6 . A tube pump, comprising:
 a casing including an arc-shaped inner circumferential wall surface along which a liquid-flowing tube is arranged;   a drive motor provided with a driving shaft rotatable in forward and reverse directions;   a rotor body arranged in a center position of the arc-shaped inner circumferential wall surface to rotate together with the driving shaft;   roller holders engaging with the rotor body to move both toward and away from the driving shaft on a plane perpendicular or substantially perpendicular to the driving shaft and swingably engaging with the rotor body;   pressing rollers rotatably supported on the roller holders to press the tube against the inner circumferential wall surface; and   biasing units arranged between the rotor body and the roller holders to bias the roller holders away from the driving shaft and to bias the roller holders, when swung, to be returned to a pre-swing position, the rotor body including a pair of engagement projection portions extending in an extension direction of the driving shaft, the engagement projection portions being arranged in opposite side areas of the rotor body along a direction that is perpendicular or substantially perpendicular to the extension direction of the driving shaft and the biasing direction of the biasing units, the roller holders including a pair of engagement recess portions extending in the extension direction of the driving shaft and engaging with the engagement projection portions to define rotation fulcrums of the roller holders.   
     
     
         7 . The tube pump of  claim 6 , wherein the rotor body is made of resin or the rotor body and the roller holders are made of resin. 
     
     
         8 . The tube pump of  claim 6 , wherein each of the engagement projection portions includes a metal shaft portion fixed to the rotor body and a resin collar portion covering the shaft portion. 
     
     
         9 . The tube pump of  claim 6 , wherein the engagement projection portions are defined by a single monolithic piece with the rotor body. 
     
     
         10 . The tube pump of  claim 6 , wherein the biasing units include compression coil springs, the rotor body including spring-receiving recess portions recessed toward the driving shaft and arranged to accommodate the compression coil springs.