Imbalance compensation element, pump, and method for balancing pumps driven by an electric motor

Abstract

The present invention describes an imbalance compensation element featuring spring arms for fixing onto a shaft, and that grooves in which an anaerobic adhesive can distribute itself for fixing the imbalance compensation element on a motor shaft. One embodiment includes a pump with such an imbalance compensation element. In a method for balancing such electric pumps, the axial and radial oscillation accelerations as well as the oscillation angular position of a running pump are measured. In accordance with these measurements and the balance class and balance angle values ascertained therefrom, an imbalance compensation element is fixed on the shaft. Through this invention the time and cost required for balancing pumps driven by electric motors can be reduced and the acoustic emissions can be distinctly reduced when such a pump is installed on a housing.

1 . An imbalance compensation element for fixing on one end of a motor- or pump-shaft, comprising: 
 an inner circumferential surface coaxial to a central axis, the surface having an inside diameter corresponding essentially to an outside diameter of the shaft,    wherein the inner circumferential surface has one or more flexible spring arms in a first section, wherein    the one or more spring arms are disposed so that when in an installed state, the spring arms produce a frictional connection to the shaft in at least a circumferential direction.    
   
   
       2 . An imbalance compensation element according to  claim 1 , wherein said spring arms are embodied as ring segments extending in an axial direction.  
   
   
       3 . An imbalance compensation element according to  claim 1 , wherein said inner circumferential surface features a second section having grooves running in an axial direction.  
   
   
       4 . An imbalance compensation element according to  claim 1 , further comprising a closed outer circumferential surface, 
 wherein over one or more first defined angular areas the closed outer circumferential surface is connected to said inner circumferential surface with a connection that is essentially completely filled with material, and    wherein in one or more second defined angular areas, the closed outer circumferential surface is connected to the inner circumferential surface by one or more individual bridges.    
   
   
       5 . An imbalance compensation element according to  claim 1 , wherein the imbalance compensation element comprises one piece made by an injection molding process.  
   
   
       6 . An air injection reactor pump for combustion engines drivable by an electric motor having a drive shaft, wherein 
 the pump comprises at least one impeller arranged on a drive shaft of the electric motor, and    wherein when the pump is disposed for driving by the electric motor, one end of the drive shaft projects beyond the impeller in a direction facing away from the electric motor so that an imbalance compensation element according to  claim 1  can be fixed on the one end of the shaft.    
   
   
       7 . A pump according to  claim 6 , further comprising a connection piece of said pump, coaxial to said drive shaft.  
   
   
       8 . A pump according to  claim 6 , wherein said imbalance compensation element is fixed on said drive shaft by means of an anaerobic adhesive.  
   
   
       9 . A pump according to  claim 6 , wherein 
 said imbalance compensation element further comprises an axial outer surface,    said pump impeller comprises a hub having a corresponding surface, and    the axial outer surface of the imbalance compensation element and the corresponding surface of the hub correspond in their shape.    
   
   
       10 . A method for balancing an electric pump comprising the steps of: 
 (a) providing a pump connected to an electric motor;    (b) starting the electric motor;    (c) measuring an oscillation acceleration to determine acceleration amplitudes in the axial and/or radial directions together with measuring an oscillation angular position to determine a balance angle and a balance class; and    (d) placing a classified imbalance compensation element according to  claim 1  in accordance with the determined balance angle and balance class.    
   
   
       11 . A method for balancing electric pumps according to  claim 10 , wherein said motor further comprises a drive shaft and said step (c) further comprises using a light barrier as well as a reflecting disk connected to the drive shaft with a positive engagement to measure said oscillation angular position.  
   
   
       12 . A method for balancing electric pumps according to  claim 10 , further comprising the use of a triax sensor is to measure said oscillation acceleration.  
   
   
       13 . Method for balancing electric pumps according to  claim 10 , wherein said measurements are carried out at an operating speed of the fully assembled pump.  
   
   
       14 . Method for balancing electric pumps according to  claim 10 , wherein said measurements are carried out at one or more mounts of said pump to a combustion engine or to a vehicle.  
   
   
       15 . Method for balancing electric pumps according to  claim 10 , wherein if said oscillation angular positions of said axial and radial acceleration amplitudes are not equal, said balance angle and said balance class are calculated by weighting the acceleration amplitudes taking into consideration the oscillation angular positions.  
   
   
       16 . Method for balancing electric pumps according to  claim 10 , 
 further comprising a step of fixing said imbalance compensation element in a recess of an angular degree disk at a zero position;    step (c) further comprises ascertaining the balance angle to the zero position; and    step (d) further comprises turning said imbalance compensation element before fixing said element.