Abstract:
A tandem rotary electric machine for vehicles is equipped with a primary rotary electric machine and a secondary rotary electric machine arranged in tandem mechanism, namely, of a dual stator-rotor pair mechanism. In the tandem rotary electric machine, a connection lead wire connects a stator coil wound on a stator core of the primary stator-rotor pair to a rectifier device through one of accommodation parts formed in slots of the stator core of the secondary stator-rotor pair. This structure reduces the entire size or volume of the tandem rotary electric machine and increases the mechanical safety against the impact or force from outside.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is related to and claims priority from Japanese Patent Applications No. 2005-201763 filed on Jul. 11, 2005, the contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the invention  
         [0003]     The present invention generally relates to a tandem rotary electric machine in tandem mechanism or a rotary electric machine, equipped with a single rotor shaft and dual stator-rotor pairs, applicable to various applications, movable bodies such as vehicles.  
         [0004]     2. Description of the Related Art  
         [0005]     The following prior-art patent documents D1 to D3 have disclosed a rotary electric machine equipped with dual stator-rotor pairs (hereinafter, referred to as “a tandem rotary electric machine”), in which dual Lundel type rotors are assembled in a tandem mechanism, and which is capable of generating different voltages independently. 
    D1: Japanese patent laid open publication NO. JP H1-157251;     D2: Japanese patent laid open publication NO. JP H5-137295; and     D3: Japanese patent laid open publication NO. JP H5-308751.    
 
         [0009]     Further, the prior-art patent document D4 has disclosed an electrical machine such as alternator for motor cars having a dual pole system cooperating with dual stator windings. 
    D4: U.S. Pat. No. 5,233,249 (corresponding to Japanese patent laid open publication NO. JP H5-500300).    
 
         [0011]     Using the tandem mechanism with the Lundel type rotors can reduce the entire size of a rotary electric machine. Such a tandem rotary electric machine is capable of controlling the electricity generation to generate and output different voltages independently. In other words, the tandem rotary electric machine can be manufactured with a compact size at a relatively low manufacturing cost. Further, such a tandem rotary electric machine can reduce its mounting space in a vehicle when compared with the case where two different non-tandem rotary electric machines are mounted on a vehicle.  
         [0012]     Such a tandem rotary electric machine is used as a dual-voltage rotary electric machine having a double-voltage power system capable of generating and supplying both a normal 12-volt power source widely used and a 42 volt power source as a high voltage.  
         [0013]     Because a rectifier device is placed or arranged at the outer end of a secondary stator-rotor pair along the axis direction of such a tandem rotary electric machine, it is necessary to electrically connect the stator of a primary stator-rotor pair to the rectifier device through lead wires (hereinafter, referred to as “connection lead wires”).  
         [0014]     The prior art patent document D2 has proposed to wire such connection lead wires on the outer peripheral end of the secondary stator-rotor pair along its radial direction.  
         [0015]     The inventors according to the present invention have disclosed new stator-coil mechanism using a sequential segment joining type stator coil that is applicable to the rotary electric machine field. For example, following patent documents D5 to D12 have been disclosed. The sequential segment joining type stator coil can increase the occupancy or share rate of segment conductors (as a stator coil) in each slot, arrange the entire shape of the stator coil with a compact size, and thereby reduce the entire size of the rotary electric machine. 
    D5: Japanese patent laid open publication NO. JP 2004-048939;     D6: U.S. Pat. No. 6,774,528 and U.S. Pat. No. 6,995,492 (corresponding to Japanese patent laid open publication NO. JP 2004-048941);     D7: U.S. Pat. No. 6,979,926 and US publication No. 2006/0033394A 1 (corresponding to Japanese patent laid open publication NO. JP  2004-064914);     D8: U.S. Pat. No. 6,825,589 (corresponding to Japanese patent laid open publication NO. JP 2004-048967);     D9: Japanese patent laid open publication NO. JP 2004-032987;     D10: U.S. Pat. No. 6,833,648 (corresponding to Japanese patent laid open publication NO. JP 2004-032882);     D11: US publication No. 2003/0233748A1 (corresponding to Japanese patent laid open publication NO. JP 2004-032884); and     D12 : U.S. Pat. No. 6,910,257 (corresponding to Japanese patent laid open publication NO. JP 2004-032890).    
 
         [0024]     Recent trend in this rotary electric machine field needs to further reduce the entire size and weight of the rotary electric machine. However, because the tandem rotary electric machine tends to increase the longitudinal length along its axis direction, there is a strong demand to reduce the entire size and weight of the rotary electric machine.  
         [0025]     Although the patent document D2 has disclosed the manner to wire the connection lead wires along the axis direction at the outer peripheral end of a secondary stator-rotor pair in the tandem rotary electric machine, this manner increases the volume or size of the rotary electric machine along the radial direction in order to keep the electrical insulation of the connection lead wires and further to achieve the mechanical protection and thermal protection against outer impact and shock. As a result, this manner decreases the degree of adaptation of the tandem rotary electric machine to various applications, in particular, to vehicles equipped with various types of vehicle engines.  
       SUMMARY OF THE INVENTION  
       [0026]     It is an object of the present invention to provide an improved tandem rotary electric machine having dual stator-rotor pairs in tandem mechanism with a simple configuration without increasing the total size, volume and weight.  
         [0027]     According to one aspect of the present invention, a tandem rotary electric machine has a primary stator-rotor pair, a secondary stator-rotor pair, and a rectifier device. Each pair of the primary stator-rotor pair and the secondary stator-rotor pair has a rotor core on which field windings being wound and a stator core on which a stator coil being wound. Those rotor cores are fixed to a same rotary shaft and placed adjacently to each other in its axis direction, and driven simultaneously by the power of a vehicle engine, for example. The rectifier device is configured to rectify independently output powers such as output voltages provided from both the primary stator-rotor pair and the secondary stator-rotor pair. The rectifier device is placed at the outside portion of the secondary stator-rotor pair in the axial direction, and in particularly, separated from the primary stator-rotor pair. The tandem rotary electric machine further has a controller configured to control independently the exciting current flowing through the field windings of the rotor cores in both the primary and secondary stator-rotor pairs. Although it is preferred to use a Lundel type rotor core as the rotor core, the present invention is not limited by this manner and it is therefore acceptable to use another types of rotor cores other than the Lundel type. Further, the concept of the present invention is also applicable to an electric motor as the rotary electric machine, to a vehicle stator, for example. Still further, it is possible to add an additional stator-rotor pair in tandem mechanism in addition to the configuration of the dual stator-rotor pairs.  
         [0028]     The tandem rotary electric machine according to one aspect of the present invention has one of features in which the stator coil of the primary stator-rotor pair is electrically connected to the rectifier device through a connection lead wire that is penetrated in an accommodation part formed in a slot of the stator core of the secondary stator-rotor pair. Because the stator coil of the primary stator-rotor pair is electrically connected to the rectifier device through the connection lead wire penetrated through the slot of the stator core of the secondary stator-rotor pair placed near the rectifier device, it is possible to prevent any expansion of the entire volume or size of the tandem rotary electric machine in the radial direction.  
         [0029]     Because the slot occupancy rate becomes low, namely only is increased a little even if the secondary stator-rotor pair uses a normal wire-wound stator coil as its stator coil when compared with the case of the primary stator-rotor pair, it is possible to penetrate easily the connection lead wire through the slot of the stator core using the normal wire-wound stator coil of the secondary stator-rotor pair.  
         [0030]     According to another aspect of the present invention, the stator coil wound on the stator cores in both the primary stator-rotor pair and the secondary stator-rotor pair are sequential segment joining type stator coil. Each of the sequential segment joining type stator coil is inserted in the corresponding slot formed in the stator core in one direction and adjacent front terminals of the adjacent sequential segment joining type stator coil are electrically connected by welding in order to form the stator coil. The stator core of the secondary stator-rotor pair has a slot having plural accommodation parts and the connection lead wire is penetrated through at least one accommodation part where no segment conductor is inserted and penetrated. It is thereby possible to penetrate the connection lead wire to one accommodation part in the slot in the stator core of the secondary stator-rotor pair without difficulty and causing any problem when the sequential segment joining type stator coil of a high occupancy rate in slot are used as the stator coil.  
         [0031]     Further, according to another aspect of the present invention, the connection lead wire is penetrated through the slot of the stator core of the secondary stator-rotor pair. The connection lead wire includes a lead wire to be used for penetrating through a slot, one end of the lead wire is electrically connected to one end of the stator coil in the primary stator-rotor pair. That is, according to the aspect of the present invention, the lead wire connected to one end of the stator coil of the primary stator-rotor pair is not used as the connection lead wire, namely, this lead wire is not penetrated through the slot of the stator core of the secondary stator-rotor pair. The connection lead wire that is penetrated in advance through the slot in the stator core of the secondary stator-rotor pair is used and electrically connected to the one end of the stator coil of the primary stator-rotor pair. This manner can reduce the manufacturing steps and time.  
         [0032]     Still further, according to another aspect of the present invention, the connection lead wire is penetrated through the slot of a same phase of the stator core of the secondary stator-rotor pair. That is, the armature current of the primary stator-rotor pair flowing through the connection lead wire becomes a half-turn stator current in the slot of the stator core of the secondary stator-rotor pair. This can avoid the occurrence of fluctuation of magnetic field in the secondary stator-rotor pair by the phase current flowing through the stator coil of the primary stator-rotor pair.  
         [0033]     Still further, according to another aspect of the present invention, both the primary stator-rotor pair and the secondary stator-rotor pair have the same number of the stator cores having a same sectional shape, and have the same sectional area of the sequential segment joining type stator coil. This can achieve a simplification of the manufacturing process.  
         [0034]     Moreover, according to another aspect of the present invention, the tandem rotary electric machine has a slip ring power supply mechanism and a controller. The slip ring power supply mechanism is configured to supply electric power to both the field windings of the primary stator-rotor pair and the secondary stator-rotor pair. The controller has field current control elements such as transistors fixed to both the rotor cores. The field current control elements are configured to independently control exciting currents flowing through the field windings of the rotor cores of the primary stator-rotor pair and the secondary stator-rotor pair.  
         [0035]     That is, according to the tandem rotary electric machine of the present invention, the common slip ring power supply mechanism can supply the electric power to both the field windings of the rotor cores of both the primary and secondary stator-rotor pairs. This can achieve the simplification of the entire configuration of the tandem rotary electric machine and reduce the friction loss caused by the brushes, and thereby reduce the entire size and weight of the rotary electric machine. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0036]     A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:  
         [0037]      FIG. 1  is a schematic sectional diagram of a tandem rotary electric machine having dual stator-rotor pairs according to a first embodiment of the present invention;  
         [0038]      FIG. 2  is a circuit diagram of the tandem rotary electric machine shown in  FIG. 1 ;  
         [0039]      FIG. 3  is a circuit diagram of the tandem rotary electric machine according to a second embodiment of the present invention;  
         [0040]      FIG. 4  is a diagram showing an exciting current control circuit in the tandem rotary electric machine according to a third embodiment of the present invention;  
         [0041]      FIG. 5  is a schematic diagram showing a placement of stators and stator coil in both a primary and secondary stator-rotor pairs of the tandem rotary electric machine according to a fourth embodiment of the present invention;  
         [0042]      FIG. 6  is a schematic diagram showing a placement of stator coil of the primary stator-rotor pair placed at the frond end of the tandem rotary electric machine according to the fourth embodiment; and  
         [0043]      FIG. 7  is a schematic diagram showing a placement of stator coil of the secondary stator-rotor pair placed at the rear end of the tandem rotary electric machine according to the fourth embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0044]     Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the various embodiments, like reference characters or numerals designate like or equivalent component parts throughout the several diagrams. A tandem rotary electric machine or a vehicle alternator according to the present invention is applicable to various devices and mounted on movable bodies such as a vehicle.  
       First Embodiment  
       [0000]     (Entire Configuration)  
         [0045]     The entire configuration of a tandem electric rotary machine for vehicle (or a vehicle alternator) according to the first embodiment of the present invention will now be described with reference to  FIG. 1 .  
         [0046]      FIG. 1  is a sectional view along a rotor shaft direction of the tandem electric rotary machine having dual stator-rotor pairs, a primary rotary electric machine section  2  (also referred to as G 1  in the diagrams) and a secondary rotary electric machine section  3  (or referred to as G 2  in the diagrams), arranged in a tandem mechanism according to the first embodiment. The tandem electric rotary machine has a housing  1 , the primary rotary electric machine section  2  (G 1 ), the secondary rotary electric machine section  3  (G 2 ), a rotor shaft  4 , a pulley  5 , bearings  6  and  7 , a rectifier  8 , a regulator  9 , and a slip ring power supply device  10 .  
         [0047]     As shown in  FIG. 1 , the housing  1  comprises a front housing  11 , a center housing  12 , and a rear housing  13 . Those housing components  11 ,  12 ,  13  of the housing  1  are fixed tightly together by through bolts  14 . The rotor shaft  4  is supported to the housing  1  through the bearings  6  and  7 . The pulley  5  is fixed to the front end part of the rotor shaft  4  that protrudes from the front end surface of the housing  1 . The rectifier device  8 , the regulator  9 , and the slip ring power supply device or mechanism  10  are fixed to the rear housing  13  placed at the rear end of the secondary rotary electric machine section  3  (G 2 ).  
         [0048]     The primary rotary electric machine has a primary stator-rotor pair that has made of a Lundel type rotor core  21 , field coil  22 , a stator core  23 , and stator coil  24 . The individual field coil  22  is wound on the Lundel type rotor core  21 . The stator core  23  is arranged in radial direction on the outer surface of the Lundel type rotor core  21 . The individual stator coil  24  is wound on the stator core  23 .  
         [0049]     The Lundel type rotor core  21  is made of a pair of half core bosses faced to each other. Each half core boss has a boss section  211 , a pole section  212  as a claw base part extended outside from the boss section  211  in the radial direction, and a claw part  213  (a claw pole or a claw magnetic pole). The field coil  22  is wound on the boss section  211  of the Lundel type rotor core  21 . The stator core  23  is placed tightly between the front housing  11  and the center housing  12 . The stator coil  24  is wound on the stator core  23 .  
         [0050]     The secondary rotary electric machine section  3  (G 2 ) has a secondary stator-rotor pair that is made of a Lundel type rotor core  31 , a field coil  32 , a stator core  33 , and a stator coil  34 . The individual field coil  32  is wound on the Lundel type rotor core  31 . The stator core  33  is arranged in the radial direction on the outer surface of the Lundel type rotor core  31 . The individual stator coil  34  is wound on the stator core  33 .  
         [0051]     The Lundel type rotor core  31  is made of a pair of half core bosses faced to each other. Each half core boss has a boss section  311 , a pole section  312  as a claw base part extended outside from the boss section  311  in the radial direction, and a claw part  313  (a claw pole or a claw magnetic pole). The field coil  32  is wound on the boss section  311  of the Lundel type rotor core  31 . The stator core  33  is placed tightly between the center housing  12  and the rear housing  13 . The stator coil  34  is wound on the stator core  33 . Because each of the primary rotary electric machine section  2  (G 1 ) and the secondary rotary electric machine section  3  (G 2 ) has the well-known typical Lundel type rotor core, the explanation for the configuration and operation is omitted here.  
         [0000]     (Explanation for Circuit Configuration)  
         [0052]     A description will now be given of the circuit configuration of the tandem rotary electric machine of the present invention with reference to  FIG. 2 .  
         [0053]     The stator coil  24  has three phase windings U, V, and W in a star connection and provide a three phase AC voltage to a three phase full wave rectifier  81 . The three phase full wave rectifier  81  performs the full wave rectifying and supplies the output current i 1  to the outside of the rotary electric machine.  
         [0054]     The output terminals of the phase windings U, V, and W are connected to three AC input terminals  811 ,  812 , and  813  of the three phase full wave rectifier  81  through connection lead wires  35 ,  36 , and  37 , respectively.  
         [0055]     Similarly, the stator coil  34  has three phase windings U′, V′, and W′ in a star connection and provide a three phase AC voltage to a three phase full wave rectifier  82 . The three phase full wave rectifier  82  performs the full wave rectifying and supplies the output current i 2  to the outside of the rotary electric machine.  
         [0056]     The output terminals of the phase windings U′, V′, and W′ are connected to three AC input terminals of the three phase full wave rectifier  82  through connection lead wires, respectively. The reference characters U and U′ designate the same phase, V and V′denote the same phase, and also U and U′ indicate the same phase. The stator coil  24  in the primary stator-rotor pair has the phase windings U, V, and W, and the stator coil  34  in the secondary stator-rotor pair has the phase windings U′, V′, and W′.  
         [0057]     The slip ring power supply device  10  has a pair of slip rings. One of the slip rings is a common terminal of the field windings connected to the ground voltage level. The other of the slip rings is connected to a positive terminal of a battery (not shown) through which the voltage of the battery is supplied.  
         [0058]     A pair of field current control transistors is fixed to each of the rotor cores  21  and  31 . Those field control transistors controls independently the field current flowing through the field coil  22  in the primary stator-rotor pair and the field current flowing through the field coil  32  in the secondary stator-rotor pair.  
         [0059]     The regulator  9  controls ON/OFF operation of those field current control transistors in order to control the magnitude of the field current in the field coils  22  and  32 , independently.  
         [0060]     The stator coil  34  of the secondary rotary electric machine section  3  has a large turn number rather than that of the stator coil  24  of the primary rotary electric machine section  2 . The primary rotary electric machine section  2  provides a normal voltage power (as a low voltage  12  Volts, for example). Through the embodiments of the present invention, the low voltage power, the 12V power is normally provided to and used by low voltage loads (not shown) in a vehicle. The primary rotary electric machine section  2  continuously provides the 12V power to those low voltage loads which need the low voltage power of 12V at all times (as a high priority power source).  
         [0061]     On the contrary, the secondary rotary electric machine section  3  generates and provides a high voltage power (42 volts, for example) to high voltage loads (not shown) incorporated in a vehicle. The secondary rotary electric machine section  3  provides the 42V power to those high voltage loads (not shown) which need the high voltage power of 42V optionally (as a low priority power source).  
         [0000]     (Explanation for the Stator Coil  24  and the Stator Coil  34 )  
         [0062]     A description will now be given of the configuration of the stator coil  24  in the primary rotary electric machine section  2  and the stator coil  34  in the secondary rotary electric machine section  3  in the tandem rotary electric machine of the embodiment with reference to  FIG. 1 .  
         [0063]     Each of the stator coils  24  and  34  is made of sequential segment joining type stator coil which has been disclosed in the patent documents D5 to D12 , and some of the inventors of which are also the inventors of the present invention.  
         [0064]     In the structure of each of the stator coils  24  and  34  using the sequential segment joining type stator coil, the leg parts (as a line part) of a pair of segment conductors of a U-shape are firstly inserted independently along the axis direction into slots of the stator cores. The slot are separated to each other by the electric angle of m:. The front parts of a pair of the U-shaped segment conductors extended from those slots are then welded sequentially in order to form wave-shaped windings or overlap-shaped windings. The patent documents D5 to D12 have disclosed the configuration and manufacturing manners of the stator coil wound on the stator cores using the sequential segment joining type stator coil. The explanation for them is therefore omitted here.  
         [0065]     The number of the slots in the stator core and the number of segment conductors per slot are selected optionally according to various applications.  
         [0066]     As shown in  FIG. 1 ,  FIG. 6 , and  FIG. 7 , each slot has four segment accommodation parts along the radial direction of the stator core to which four sequential segments for the stator coil  24  and the stator coil  34  are inserted and fixed.  
         [0067]     The leg parts of large segment conductors are inserted into the first and fourth accommodation parts at the innermost end and the outermost end of each slot and the leg parts of small segment conductors are inserted into the secondary and third accommodation parts at the middle end of the slot. However, the present invention is not limited by the above accommodation manner of the segment conductors (SCs) according to the various applications and demands.  
         [0068]     Each phase winding of the three phases (U. V, and W) of the stator coil  24  has N1/3 small segment conductors and N1/3 large segment conductors, where N 1  is the number of slots in the stator core  23 , and N 2  is the number of slots in the stator core  33 . Each phase winding of the three phases (U, V, and W) has N1/3 small segment conductors, and N1/3 large segment conductors. The stator coil  24  is a small coil part made of N1/3 small sequential conductors (SCs) connected to each other sequentially, and a large coil part made of N1/3 large sequential conductors (SCs) connected to each other sequentially, where the small SCs and the large SCs are connected in series.  
         [0069]     Similar to the stator coil  24 , each phase winding of the three phases (U′, V′, and W′) of the stator coil  34  has N2/3 small segment conductors and N2/3 large segment conductors, where N 2  is the number of slots in the stator core  33 . Each phase winding of the three phases (U′, V′, and W′) has N2/3 small segment conductors and N2/3 large segment conductors. Each stator coil  34  is a small coil part made of N2/3 small sequential conductors (SCs) connected to each other sequentially, and a large coil part made of N2/3 large sequential conductors (SCs) connected to each other sequentially, where the small SCs and the large SCs are connected in series. As described later, the turn number of each of the three phase windings U′, V′, and W′ in the stator coil  34  is less one turn.  
         [0070]     In more detailed, each of the phase windings U′, V′, and W′ of the stator coil  34  of the secondary stator-rotor pair  3  arranged at the rectifier device end (or at the rear end) of the tandem rotary electric machine of the embodiment is less the primary half turn and the final half turn. In addition, the primary segment conductor (SC) and the final segment conductor (SC) of each of the phase windings U′, V′, and W′of the stator coil  34  of the secondary stator-rotor pair  3  is made of the I-shaped SC, not the U-shapes SC. The primary I-shaped SC as the primary half turn of each of the phase windings U′, V′, and W′acts as a terminal lead wire of each of the phase windings U′, V′, and W′. Further, the final I-shaped SC as the final halt turn of each of the phase windings U′, V′, and W′ is connected to each other and becomes an intermediate voltage node. The terminal lead wire is connected to the connection lead wire through which the stator coil is electrically connected to the rectifier device  8 .  
         [0071]     In the stator core  33 , a pair of the segment conductor accommodation parts that are separated to each other by electric angle of π becomes space area where no segment conductor is inserted. The space area of those segment conductor accommodation parts are designated by the reference characters P 1  and P 2 , for example, as shown in  FIG. 6 .  
         [0072]     That is, in the secondary rotary electric machine section  3  (G 2 ), each of the stator windings U′, V′, and W′of the stator coil  34  of the secondary stator-rotor pair has ((2N2/3)−1) turns that is less by one turn when compared with the normal turn-number (2N2/3).  
         [0073]     On the contrary, in the primary rotary electric machine section  2  (G 1 ), each of the stator windings U, V, and W of the stator coil  24  of the primary stator-rotor pair has (2N/3) turns. The primary segment conductor (SC) and the final segment conductor (SC) of each of the phase windings U, V, and W of the stator coil  24  of the primary stator-rotor pair is made of a I-shaped SC, not U-shapes SC. The primary I-shaped SC of each of the phase windings U, V, and W becomes a terminal lead wire of each of the phase windings U, V, and W. Further, the final I-shaped SC of each of the phase windings U, V, and W is connected to each other and becomes an intermediate voltage node. Each of the stator windings U, V, and W of the stator coil  24  of the primary stator-rotor pair therefore has (2N1/3) turns.  
         [0074]     The terminal lead wires  101 ,  102 , and  103  of the phase windings of the stator coil  24  in the primary stator-rotor pair of the primary rotary electric machine section  2  (G 1 ) must run or be wired to the AC input terminals of the three phase full wave rectifier device  8  over the secondary stator-rotor pair in the secondary rotary electric machine section  3  (G 2 ) along the axis direction of the secondary rotary electric machine  3  (G 2 ).  
         [0075]     In particular, according to the configuration of the embodiment of the present invention shown in  FIG. 1  and  FIG. 6  and  FIG. 7 , the connection lead wires  35 ,  36 , and  37  are inserted through the segment conductor accommodation parts P 1  or P 2  (see  FIG. 6 ) of space are and the terminal lead wires  101 ,  102 , and  103  of the phase windings U, V, and W in the primary stator-rotor pair are connected to the AC input terminals  811 ,  812 , and  813 , respectively through the connection lead wires  35 ,  36 , and  37  that penetrate through the segment conductor accommodation parts P 1  or P 2 . Further, the front part of the terminal lead wire  101  of the U phase winding is connected to the front part of the connection lead wire  35  by welding. The front part of the terminal lead wire  102  of the V phase winding is connected to the front part of the connection lead wire  36  by welding. The front part of the terminal lead wire  103  of the W phase winding is connected to the front part of the connection lead wire  37  by welding. The rear part of the connection lead wire  35  is connected to the AC input terminal  811  of the three phase full wave rectifier device  81 . The rear part of the connection lead wire  36  is connected to the AC input terminal  812  of the three phase full wave rectifier device  81 . The rear part of the connection lead wire  37  is connected to the AC input terminal  813  of the three phase full wave rectifier device  81 .  
         [0076]     According to the configuration of the tandem rotary electric machine having the above configuration of the connection lead wires  811 ,  812 , and  813  and the terminal lead wires  101 ,  102 , and  103  in the primary stator-rotor pair and the secondary stator-rotor pair, it is possible to connect the stator coil  24  in the primary rotary electric machine G 1  to the three phase full wave rectifier  81  of the rectifier device  8  efficiently with a compact size without increasing the entire volume or size of the tandem rotary electric machine in addition to the effect obtained by using the sequential segment joining type stator coil having a high occupancy or share of segment conductors (as the stator coil  34 ) in each slot.  
       MODIFICATIONS  
       [0077]     A description will now be given of various modifications of the configuration of the tandem rotary electric machine of the present invention with reference to  FIG. 1 .  
         [0078]     In the embodiment described above, the sequential segment joining type stator coil is adapted to the stator coil  24  in the primary stator-rotor pair of the primary rotary electric machine section  2  (G 1 ). The present invention is not limited by this configuration. For example, it is possible to apply to the normal wire-wound stator coil, not the sequential segment joining type stator coil, the concept of the present invention, regarding the connection of the connection lead wires and the lead wires. In the winding type stator coil, because coil conductors of a round-cable shape and a circle sectional area are inserted into corresponding slots in the stator cores  23  and  33 , the occupancy rate or share rate of the wires in each slot is small and an idle spaces are present in the slots. Therefore it is possible to insert easily the connection lead wires  35 ,  36 , and  27  into the idle spaces in the slots after the completion of the windings of the stator coil.  
         [0079]     It is preferred that the connection lead wire  35  connected to the U phase coil of the stator coil  24  is connected to the rectifier device  8  through the slot through which the U′ phase coil (as shown in  FIG. 2 ) of the stator coil  34  is inserted. That is, it is preferred to flow the current in the U′phase sequential segment conductor of the stator coil  34  and the current in the connection lead wire  35  in the same direction, namely, the same phase. Similarly, it is preferred that the connection lead wire  36  connected to the V phase coil of the stator coil  24  is connected to the rectifier device  8  through the slot through which the V′ phase coil (as shown in  FIG. 2 ) of the stator coil  34  is inserted. That is, it is preferred to flow the current in the V′ phase sequential segment conductor of the stator coil  34  and the current in the connection lead wire  36  in the same direction, namely the same phase. Still similarly, it is preferred that the connection lead wire  37  connected to the W phase coil of the stator coil  24  is connected to the rectifier device  8  through the slot through which the W′ phase coil (as shown in  FIG. 2 ) of the stator coil  34  is inserted. That is, it is preferred to flow the current in the W′ phase sequential segment conductor-of the stator coil  34  and the current in the connection lead wire  37  in same direction (same phase).  
       Second Embodiment  
       [0080]     A description will now be given of the configuration of the tandem rotary electric machine according to the second embodiment of the present invention with reference to  FIG. 3 .  
         [0081]     In the second embodiment, a DC high voltage output terminal of the three phase full wave rectifier  81  for the primary rotary electric machine section  2  (G 1 ) is connected to the DC low voltage output terminal of the three phase full wave rectifier  82  for the secondary rotary electric machine section  3  (G 2 ) through a connection node A.  
         [0082]     It is possible to adjust the output voltage ( 12  Volts) and output current from the three phase full wave rectifier  81  by adjusting the magnitude of the exciting current If 1  to be flowing into the field coil  22 . Similarly, it is possible to adjust the output voltage (42 volts) and output current from the three phase full wave rectifier  82  by adjusting the magnitude of the exciting current If 2  to be flowing into the field coil  32 . Thus, through the connection node A, both the high DC voltage (42 volts) output terminal of the three phase full wave rectifier  81  is connected to the low DC voltage (12 Volts) output terminal of the three phase full wave rectifier  82 . This configuration reduces the load of the secondary rotary electric machine (G 2 ) for generating high voltage (42 volts).  
       Third embodiment  
       [0083]     A description will now be given of the configuration of the tandem rotary electric machine according to the third embodiment of the present invention with reference to  FIG. 4 .  
         [0084]     As shown in  FIG. 4 , the slip ring power supply device  10  has a pair of brush  200  and a slip ring  201  contacted to the brush  200 , and a pair of brush  202  and a slip ring  203  contacted to the brush  202 . Reference number  204  designates a transistor for controlling ON/OFF operation of the exciting current flowing through the field coil  22 . Reference number  205  denotes a transistor for controlling ON/OFF operation of the exciting current flowing through the field coil  32 . Reference number  206  indicates an emitter follower transistor for amplifying the base current of the transistor  204 ,  207  designates an emitter follower transistor for amplifying the base current of the transistor  205 , and reference character D indicates fly wheel diodes. Those electric components such as the transistors  204 ,  205 ,  206 , and  207 , and the fly wheel diodes D are fixed to and mounted on the rotor core and are rotated by the rotation of the rotor core. Reference number  208  designates a de-multiplexer, mounted on the rotor core, configured to distribute control signals to be transferred optically from the regulator  9  mounted on the regulator  9  through optical devices such as rotary photo couplers under non-contact condition. As described above, the third embodiment can make the slip ring mechanism with a simple configuration, and thereby reduce the entire size of the tandem rotary electric machine.  
       Fourth Embodiment  
       [0085]      FIG. 5  is a schematic diagram showing a placement of the stators and the stator coil in both the primary and secondary stator-rotor pairs of the tandem rotary electric machine according to the fourth embodiment of the present invention.  
         [0086]     Each phase of the stator coil  24  has a primary coil and a secondary coil connected in series. The primary coil is made of the sequential segment conductors inserted to and accommodated in the corresponding conductor accommodation part of the first and second layers in each slot. The secondary coil is made of the sequential segment conductors inserted to and accommodated in the corresponding conductor accommodation part of the third and fourth layers in each slot. Similarly, each phase of the stator coil  34  has a primary coil and a secondary coil connected in series. The primary coil is made of the sequential segment conductors inserted to and accommodated in the corresponding conductor accommodation part of the first and second layers in each slot. The secondary coil is made of the sequential segment conductors inserted to and accommodated in the corresponding conductor accommodation part of the third and fourth layers in each slot.  
         [0087]      FIG. 6  shows the placement or arrangement of the stator coil of the U′ phase in the secondary stator-rotor pair  3  of the secondary rotary electric machine section  3  (G 2 ), when the number of the slots in each phase of the stator core  33  is four.  FIG. 7  shows the placement or the arrangement of the stator coil of the U phase in the primary stator-rotor pair of the primary rotary electric machine section  2  (G 1 ) when the number of the slots in each phase of the stator core  33  is four.  
         [0088]     In both  FIG. 6  and  FIG. 7 , the solid lines show U-shaped head parts of the coil ends  242  and  342  of the U-shaped segment conductors placed or arranged at the rear end of the primary stator-rotor pair and the secondary stator-rotor pair. Further, the dotted lines show both leg parts  241  and  341  of the coil ends of the U-shaped segment conductors placed or arranged at the front end of the primary stator-rotor pair and the secondary stator-rotor pair.  
         [0089]     As shown in  FIG. 6 , the reference characters P 1  and P 2  indicate the idle space in the slots S 1  and S 2  of the stator core  33  in the secondary stator-rotor pair of the secondary rotate electric machine section  3  (G 2 ) supplying the high voltage (42 volts) power. Reference number  301  denotes an I-shape sequential segment conductor as the terminal lead wire of the U phase winding of the stator core  33 . The I-shape sequential segment conductor  301  also becomes the start end portion of the stator coil  34  wound on the stator core  33 . Reference number  303  designates an I-shape sequential segment conductor as the terminal end portion of the stator coil  34  wound on the stator core  33 . The I-shape sequential segment conductor  303  becomes the middle voltage point. Reference characters S 1  to S 4  denote slot numbers.  
         [0090]     The connection lead wire connected to the I-shaped sequential segment conductor  301  as the start end of the U′ phase winding is connected to the rectifier device  8  through the connection lead wire inserted in one of the idle spaces P 1  and P 2 . Thus, the I-shaped sequential segment conductor  301  is connected to the rectifier device  8  through the connection lead wire and the connection lead wire penetrated through the idle space P 1  or P 2  where no segment conductor is inserted. The selection of the idle space P 1  or P 2  can be performed according to its working efficiency.  
         [0091]     After the completion of the manufacturing of the tandem rotary electric machine, the lead wire becomes a part of the connection lead wire through which the stator coil is electrically connected to the rectifier device  8 .  
         [0092]     While specific embodiments of the present invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limited to the scope of the present invention which is to be given the full breadth of the following claims and all equivalent thereof.