Motor with eccentric part and pump device using the same

Abstract

In the present invention, without forming a rotational shaft ( 30 ) per se in an eccentric manner, the eccentric structure is provided to the whole structure including a ball bearing ( 50 ). Accordingly, in place of cutting a side of the rotational shaft ( 30 ), the eccentric ball bearing ( 50 ) is joined to a shaft portion of the straight rotational shaft ( 30 ) so as to obtain an eccentric portion. That is, the eccentric portion is constituted of the shaft portion which has an axis aligned with an axis of the rotational shaft ( 30 ) and the eccentric ball bearing ( 50 ) which is joined to the shaft portion. As the eccentric ball bearing, it is optimum to adopt a mode in which an inner side thereof having a smaller diameter is formed in an eccentric manner. The eccentric ball bearing ( 50 ) is constituted of an inner lace ( 52 ) which is arranged eccentric with respect to the axis of the rotational shaft ( 30 ), an outer lace ( 54 ) which surrounds an outside of the inner lace ( 52 ) and balls ( 55 ) which are supported between the outer lace ( 54 ) and the inner lace ( 52 ).

1 . A motor having an eccentric portion including a rotational shaft which has an axis and supports an armature and a commutator thereon, and an eccentric portion which is eccentrically configured with respect to the axis on the rotational shaft, the eccentric portion constituting an output portion for driving an external equipment, wherein 
 the eccentric portion includes a shaft portion of the rotational shaft which has an axis equal to the axis, and an eccentric ball bearing which is joined to the rotational shaft and has another axis which is eccentric with respect to the axis of the rotational shaft and the shaft portion.    
   
   
       2 . A motor according to  claim 1 , wherein the eccentric ball bearing is constituted of an inner lace which is eccentric with respect to the axis of the rotational shaft and the shaft portion, an outer lace which is positioned outside the inner lace and has an axis equal to the axis of the rotational shaft and the shaft portion, and balls which are supported between the outer lace and the inner lace.  
   
   
       3 . A motor according to  claim 1 , wherein the eccentric ball bearing is jointed to a portion of the rotational shaft in a close fit state.  
   
   
       4 . A motor according to  claim 1 , wherein the armature, the commutator and the eccentric portion are arranged on the axis in the order.  
   
   
       5 . A motor according to  claim 1 , wherein the motor has an output of 150 W or less.  
   
   
       6 . A pump device including a rotational shaft which has an axis and supports an armature and a commutator thereon, an eccentric portion which is eccentrically configured with respect to the axis on the rotational shaft, and a plunger pump which is brought into contact with the eccentric portion and is driven by an eccentric motion of the eccentric portion, wherein 
 the eccentric portion includes a shaft portion of the rotational shaft which has an axis equal to the axis, and an eccentric ball bearing which is joined to the shaft portion of the rotational shaft and has another axis which is eccentric with respect to the axis of the rotational shaft and the shaft portion.    
   
   
       7 . A pump device according to  claim 6 , wherein the eccentric ball bearing is constituted of an inner lace which is eccentric with respect to the axis of the rotational shaft and the shaft portion, an outer lace which is positioned outside the inner lace and has an axis equal to the axis of the rotational shaft and the shaft portion, and balls which are supported between the outer lace and the inner lace.  
   
   
       8 . A pump device according to  claim 6 , wherein the eccentric ball bearing is jointed to a portion of the rotational shaft in a close fit state.  
   
   
       9 . A pump device according to  claim 7 , wherein the eccentric ball bearing is jointed to a portion of the rotational shaft in a close fit state.  
   
   
       10 . A motor according to  claim 2 , wherein the eccentric ball bearing is jointed to a portion of the rotational shaft in a close fit state.  
   
   
       11 . A motor according to  claim 2 , wherein the armature, the commutator and the eccentric portion are arranged on the axis in the order.  
   
   
       12 . A motor according to  claim 2 , wherein the motor has an output of 150 W or less.