Compact and reliable structure of multi-rotor synchronous machine

Abstract

A compact and reliable structure of a multi-rotor synchronous machine which may be employed as a generator/motor for automotive vehicles is provided. The machine includes an outer rotor having permanent magnets, an inner rotor having permanent magnets disposed to be rotatable relative to the outer rotor, a stator core having armature coils interlinking with field magnetic fluxes produced by the outer and inner rotors, and a rotor-to-rotor relative rotation controlling mechanism. A relative angle between the outer and inner rotors is controlled within a given angular range by controlling the phase and quantity of current flowing through the armature coils to rotate the inner rotor relative to the outer rotor through the rotor-to-rotor relative rotation controlling mechanism, thereby changing the magnetic fluxes interlinking with the armature coils as needed.

What is claimed is:  
     
         1 . A multi-rotor synchronous machine comprising: 
 a fist rotor having permanent magnet field poles, secured to an output member;    a second rotor having permanent magnet field poles, disposed to be rotatable relative to said first rotor;    a stator core having armature coils interlinking with field magnetic fluxes produced by the permanent magnet field poles of said first and second rotors; and    a rotor-to-rotor relative rotation controlling mechanism designed to allow said second rotor to rotate relative to said first rotor within a given angular range and prohibit said second rotor from rotating out of the given angular range.    
     
     
         2 . A multi-rotor synchronous machine as set forth in  claim 1 , wherein said rotor-to-rotor relative rotation controlling mechanism includes a first stopper working to limit rotation of said second rotor relative to said first rotor in a first direction over a first angular range and a second stopper working to limit rotation of said second rotor relative to said first rotor in a second direction opposite the first direction over a second angular range.  
     
     
         3 . A multi-rotor synchronous machine as set forth in  claim 2 , wherein said rotor-to-rotor relative rotation controlling mechanism includes an elastic member which is engagement at one end thereof with said first rotor and at the other end with said second rotor to urge said first and second rotors in opposite directions.  
     
     
         4 . A multi-rotor synchronous machine as set forth in  claim 1 , wherein said stator core is made of a hollow cylindrical member, and wherein said first rotor and said second rotor are disposed coaxially with an outer and an inner periphery of said stator core, respectively.  
     
     
         5 . A multi-rotor synchronous machine as set forth in  claim 4 , wherein said second rotor is disposed inside the inner periphery of said stator core, and wherein said rotor-to-rotor relative rotation controlling mechanism is installed inside said second rotor.  
     
     
         6 . A multi-rotor synchronous machine as set forth in  claim 1 , wherein rotation of said second rotor relative to said first rotor is accomplished by controlling at least one of phase and quantity of current flowing through the armature coils of said stator core.  
     
     
         7 . A multi-rotor synchronous machine comprising: 
 a pair of rotors at least one of which has permanent magnet field poles, said rotors being arrayed coaxially to be rotatable relative to each other;    a stator core;    armature coils wound in said stator core, interlining with a field flux produced by said rotors;    a sensor measuring a relative angle between said rotors; and    a rotor-to-rotor relative angle controller working to establish a relative rotation between said rotors to change the relative angle measured by said sensor to a target angle.    
     
     
         8 . A multi-rotor synchronous machine as set forth in  claim 7 , wherein said stator core is made of a hollow cylindrical member, wherein said rotors are an outer rotor disposed around an outer periphery of said stator core and an inner rotor disposed around an inner periphery of said stator core, and wherein said rotor-to-rotor relative angle controller includes a relative rotation controlling mechanism disposed inside said inner rotor for controlling a relative rotation between said rotors.  
     
     
         9 . A multi-rotor synchronous machine as set forth in  claim 8 , wherein said relative rotation controlling mechanism includes an elastic member laid between said rotors in a circumferential direction thereof to keep said rotors in a neutral position, and wherein said rotor-to-rotor relative angle controller changes magnetic torques acting on said rotors to adjust a relative angle between said rotors to a target angle.  
     
     
         10 . A multi-rotor synchronous machine as set forth in  claim 9 , wherein said rotor-to-rotor relative angle controller is designed to change the magnetic torque acting on said rotors to rotate one of said rotors relative to the other from the neutral position while compressing or expanding said elastic member, thereby adjusting the relative angle between said rotors to the target angle.  
     
     
         11 . A multi-rotor synchronous machine as set forth in  claim 9 , wherein said relative rotation controlling mechanism includes a pair of elastic members secured on one of said rotors to establish the neutral position in which said rotors have a preselected angular relation therebetween when the armature coils is deenergized, and wherein said rotor-to-rotor relative angle controller changes the magnetic torques acting on said rotor to cause one of the elastic members to be compressed while expanding the other elastic member, thereby adjusting the relative angle between said rotors to the target angle.  
     
     
         12 . A multi-rotor synchronous machine as set forth in  claim 10 , wherein said relative rotation controlling mechanism includes a pair of stoppers working to define a relative rotation allowable range of said rotors.  
     
     
         13 . A multi-rotor synchronous machine as set forth in  claim 12 , wherein when said rotors are in a first relative angular position lying one of limits of the relative rotation allowable range defined by one of the stopper, a maximum torque is produced on said rotors in a direction of rotation of the multi-rotor synchronous machine, when said rotors are in a second relative angular position lying the other limit of the relative rotation allowable range defined by the other stopper, a maximum torque being produced on said rotors in a direction reverse to the direction of rotation of the multi-rotor synchronous machine.  
     
     
         14 . A multi-rotor synchronous machine as set forth in  claim 7 , wherein one of said rotors has an inertial mass two times greater than that of the other rotor or more.  
     
     
         15 . A multi-rotor synchronous machine as set forth in  claim 14 , wherein one of said rotors having the greater inertial mass is coupled to a crankshaft of an automotive engine, and the other rotor is coupled to the one of said rotors through said rotor-to-rotor relative angle controller to be rotatable relative to the one of said rotors.  
     
     
         16 . A multi-rotor synchronous machine as set forth in  claim 9 , wherein the relative rotation controlling mechanism establish an engagement between said rotors so as to allow said rotors to rotate relative to each other continuously in a given angular range.  
     
     
         17 . A drive apparatus for an automotive vehicle comprising: 
 a flywheel connected to a rear end of a crankshaft of an engine;    a generator/motor includes a stator which is located in front of said flywheel and secured to a housing and a rotor which is secured on said flywheel and faces a peripheral surface of the stator; and    a mechanical clutch establishing an engagement between said flywheel and an input shaft of a gear reduction unit disposed behind said flywheel, the input shaft extending through said flywheel coaxially with the crankshaft, said mechanical clutch including,    (a) a pressure plate supported by said flywheel nonrotatably and slidably in an axial direction of the input shaft of the gear reduction unit, said pressure plate facing a rear surface of said flywheel through a given gap,    (b) a clutch plate supported by said input shaft nonrotatably and slidably in the axial direction, said clutch plate being disposed between the rear surface of said flywheel and a front surface of said pressure plate,    (c) an annular clutch spring located behind said pressure plate, supported by said flywheel so as to urge at an outer periphery thereof a rear end surface of said pressure plate frontward,    (d) a sleeve fitted on the input shaft through a given gap between itself and an outer peripheral surface of the input shaft, said sleeve being located behind said clutch plate and secured at a rear end thereof to said housing,    (e) a release piston fitted on the outer peripheral surface of said sleeve slidably in an axial direction of said sleeve, and    (f) a release bearing fitted on said release piston or said sleeve to be movable in the axial direction to urge an inner peripheral portion of said clutch spring,    wherein said flywheel includes a small-diameter cylinder coupled at a front end thereof to the rear end of said crank shaft and a disc extending from a rear end of the small-diameter cylinder in a centrifugal direction to be engageble with said clutch plate,    wherein said clutch plate includes a cylinder which has a chamber opened rearward into which said release bearing is allowed to be inserted at least partially and which is fitted on said input shaft nonrotatably and slidably in the axial direction and a disc extending from a rear end of the cylinder between the rear end surface of said flywheel and the front end surface of said pressure plate, and    wherein at least a portion of said release piston and said release bearing are located frontward of said clutch spring.    
     
     
         18 . A drive apparatus as set forth in  claim 17 , wherein said release bearing is fitted on said release piston.  
     
     
         19 . A drive apparatus as set forth in  claim 18 , wherein said clutch plate includes a clutch damper located between the cylinder and the disc thereof for absorbing a variation in torque, a front portion of said clutch damper being disposed within a chamber formed in a rear end portion of the cylinder of said flywheel.