Rotary electrical machine and electric vehicle having the same

Abstract

A rotary electrical machine includes a rotational shaft supported by a housing for rotation about an axis, a rotor coupled with the rotational shaft, and a stator fixed to the housing and oriented to face the rotor. A rotor position changing mechanism moves the rotor in an axial direction of the rotational shaft using a portion of a torque transmitted between the rotational shaft and the rotor as a driving force. The rotor position changing mechanism controls the strength of the magnetic field between the rotor and the stator by moving the rotor toward or away from the stator.

1 . A rotary electrical machine comprising: 
 a base member;    a stator fixed to the base member;    a rotational shaft supported by the base member for rotation about an axis;    a rotor coupled with the rotational shaft and disposed so as to face the stator; and    a rotor position changing mechanism configured to transmit a torque between the rotor and the rotational shaft and to urge the rotor away from the stator along an axial direction of the rotational shaft as torque transmitted from the rotational shaft to the rotor increases.    
   
   
       2 . The rotary electrical machine of  claim 1 , wherein the rotor and rotational shaft configured to move relative to each other about the axis.  
   
   
       3 . The rotary electrical machine according to  claim 1 , wherein the rotor position changing mechanism comprises a force component generating mechanism configured to generate a force component that shifts the rotor in the axial direction of the rotational shaft in accordance with the torque transmitted between the rotational shaft and the rotor.  
   
   
       4 . The rotary electrical machine according to  claim 3 , wherein the force component generating mechanism has a helical structure via which the rotational shaft and the rotor are configured to move helically relative to each other about the axis of the rotational shaft.  
   
   
       5 . The rotary electrical machine according to  claim 3 , wherein the force component generating mechanism comprises an engaging structure via which the rotational shaft and the rotor engage each other, at least a portion of the engaging structure extending helically about the axis of the rotational shaft.  
   
   
       6 . The rotary electrical machine according to  claim 3 , wherein the force component generating mechanism comprises a helical gear unit disposed between the rotational shaft and the rotor.  
   
   
       7 . The rotary electrical machine according to  claim 3 , wherein the force component generating mechanism comprises a cam unit disposed between the rotational shaft and the rotor.  
   
   
       8 . The rotary electrical machine of  claim 1 , further comprising a spring that contacts the rotor and is configured to urge the rotor toward the stator.  
   
   
       9 . The rotary electrical machine according to  claim 8 , wherein the spring has a non-linear characteristic.  
   
   
       10 . The rotary electrical machine according to  claim 1 , wherein a size of a gap separating the rotor and the stator from each other varies in accordance with the movement of the rotor relative to the stator.  
   
   
       11 . An electric vehicle comprising the rotary electrical machine according to  claim 1  as a driving force source for operating the vehicle.  
   
   
       12 . A rotary electrical machine comprising: 
 a base member;    a stator fixed to the base member;    a rotational shaft supported by the base member for rotation about an axis;    a rotor coupled with the rotational shaft and disposed so as to face the stator, the rotor and rotational shaft configured to move relative to each other about the axis; and    a rotor position changing mechanism configured to urge the rotor toward the stator along an axial direction of the rotational shaft until the rotor reaches a predetermined location proximate the stator when the rotary electrical machine operates as an electric motor and torque is transmitted from the rotor to the rotational shaft.    
   
   
       13 . The rotary electrical machine of  claim 12 , wherein the rotor position changing mechanism is further configured to urge the rotor away from the stator along the axial direction of the rotational shaft, if transmission torque transmitted from the rotational shaft to the rotor increases, when the rotary electrical machine operates as a generator.  
   
   
       14 . The rotary electrical machine according to  claim 12 , wherein the rotor position changing mechanism comprises a force component generating mechanism configured to generate a force component that shifts the rotor in the axial direction of the rotational shaft in accordance with the torque transmitted between the rotational shaft and the rotor.  
   
   
       15 . The rotary electrical machine according to  claim 14 , wherein the force component generating mechanism has a helical structure via which the rotational shaft and the rotor are configured to move helically relative to each other about the axis of the rotational shaft.  
   
   
       16 . The rotary electrical machine according to  claim 14 , wherein the force component generating mechanism comprises an engaging structure via which the rotational shaft and the rotor engage each other, at least a portion of the engaging structure extending helically about the axis of the rotational shaft.  
   
   
       17 . The rotary electrical machine according to  claim 14 , wherein the force component generating mechanism comprises a helical gear unit disposed between the rotational shaft and the rotor.  
   
   
       18 . The rotary electrical machine according to  claim 14 , wherein the force component generating mechanism comprises a cam unit disposed between the rotational shaft and the rotor.  
   
   
       19 . The rotary electrical machine of  claim 12 , further comprising a spring that contacts the rotor and is configured to urge the rotor toward the stator.  
   
   
       20 . The rotary electrical machine according to  claim 12 , wherein a size of a gap separating the rotor and the stator from each other varies in accordance with the movement of the rotor relative to the stator.