Brushless vibration motor

Abstract

Disclosed is a brushless vibration motor having a driving circuit therein, which is capable of operating like a typical DC motor. The brushless vibration motor comprises an eccentric rotor R having an eccentric weight 5 b , a rotor case 5 and a magnet 6 which has a plurality of magnetic poles arranged in the rotor case; a shaft 2 for supporting the eccentric rotor, a housing H for supporting the shaft, a stator S which is disposed around the shaft on a stator base 1 constructing a part of the housing and which consists of armature coils to drive the rotor, and a driving circuit member 1 c which is mounted in a space K corresponding to an area of at least one armature coil.

What is claimed is:  
     
         1 . A brushless vibration motor comprising: 
 an eccentric rotor having a rotor case,    a magnet which has plural poles and which is arranged on an inner peripheral surface of the rotor case, and a weight disposed on a portion of an outer peripheral surface of the rotor case;    a shaft for supporting the eccentric rotor;    a housing for supporting the shaft, the housing having a stator base and a cover enclosing the rotor;    a stator for driving the rotor, which is disposed on the stator base to be around the shaft and which has a plurality of armature coils; and    a driving circuit member for applying electric current to the stator, which is disposed at a predetermined portion on the stator base.    
     
     
         2 . A brushless vibration vibration motor as claimed in  claim 1 , wherein the stator is a cored type of stator including a plurality of salient poles on which the armature coil is wound.  
     
     
         3 . A brushless vibration motor as claimed in  claim 2 , wherein the stator includes at least two salient poles on which the armature coil is wound and which is cooperated with the magnet having alternatively arranged magnetic poles, leaving a radial gap therebetween.  
     
     
         4 . A brushless vibration motor as claimed in  claim 3 , wherein the driving circuit member has no sensor.  
     
     
         5 . A brushless vibration motor as claimed in  claim 2 , wherein the stator has at least two salient poles which are disposed at an angular pitch of an integer times to a width of a magnetic pole and which have the armature coils wound thereon.  
     
     
         6 . A brushless vibration motor as claimed in  claim 2 , wherein the driving circuit member has at least one sensor.  
     
     
         7 . A brushless vibration motor as claimed in  claim 1 , where in the cover is attached to the stator base, enclosing the eccentric rotor.  
     
     
         8 . A brushless vibration motor as claimed in  claim 1 , wherein the stator includes air-core armature coils.  
     
     
         9 . A brushless vibration motor as claimed in  claim 8 , wherein the stator includes at least two air-core armature coils which are arranged around an axis of the shaft at a uniform angular pitch of 60 degree and which face the magnet, leaving a radial gap therebetween, the magnet having magnetic poles that are alternatively arranged in the rotor case.  
     
     
         10 . A brushless vibration motor as claimed in  claim 8 , wherein the driving circuit member has no sensor.  
     
     
         11 . A brushless vibration motor as claimed in  claim 8 , wherein the stator includes at least two air-core armature coils arranged at an angular pitch of an integer times to a width of a magnetic pole, and a driving circuit member has at least one sensor.  
     
     
         12 . A brushless vibration motor as claimed in  claim 8 , wherein the cover is mounted onto the stator base to enclose the eccentric rotor.