Electric blower

Abstract

The present invention provides an electric blower that performs: measuring an amount of airflow against a fan rotation speed of the blower with a load magnitude detected previously; determining an empirical formula to calculate a fan rotation speed to discharge an amount of target airflow in response to the magnitude of a load of the blower according to the data obtained from the above measurement repeated a plurality of times varying the magnitude of the load on the blower; operating, firstly in practice, the blower to detect the magnitude of the load of the blower, then to calculate the fan rotation speed to discharge the amount of target airflow using the empirical formula; and then changing the blower operation to the fan rotation speed given by the calculation.

1 . An electric blower comprising: 
 an electric motor;    a blower with a fan driven to rotate by the electric motor; and    a controller to control a driving of the electric motor; and    the controller comprising: 
 a load-detector to detect and to output data on a magnitude of a load of the blower;  
 a rotation-speed-calculator to calculate and to output data on a fan rotation speed required for the blower to discharge an amount of target airflow according to the magnitude of the load of the fan output from the load-detector and the given target amount of airflow;  
 a rotation-speed-selector to switch over a rotation speed from a load-detection-rotation-speed determined previously to the rotation speed required for the blower to discharge the amount of target airflow according to the data output from the rotation-speed-calculator; and  
 a timing device to determine a starting time for the load-detector, the rotation-speed-calculator and the rotation-speed-selector respectively.  
   
     
     
         2 . The electric blower of  claim 1 , wherein the load detector measures an input current to the electric motor on the load detection rotation speed and to output data on a magnitude of a load of the blower according to the current to the electric motor.  
     
     
         3 . The electric blower of  claim 2 , wherein the rotation speed calculator calculates a rotation speed required for the blower to discharge the amount of target airflow according to a plurality of values determined independently on a load of the blower, a value to show a magnitude of the load of the blower, and a value of the given amount of target airflow.  
     
     
         4 . The electric blower of  claim 3 , wherein the amount of target airflow is a value obtained by measuring an amount of airflow of the blower against a fan rotation speed, varying the fan rotation speed leaving a load of the blower kept constant.  
     
     
         5 . The electric blower of  claim 1 , wherein the electric motor is a DC motor.  
     
     
         6 . The electric blower of  claim 1 , wherein the timing device begins to work at the start of the electric blower.  
     
     
         7 . The electric blower of  claim 1 , wherein the timing device works at regular time intervals.  
     
     
         8 . The electric blower of  claim 1 , wherein the timing device works when a load of the blower has changed.