Abstract:
To obtain a rotary electric machine in which an insulation failure does not occur even when the output of the rotary electric machine is increased by improving the cooling performance at the rotor winding ends. The rotary electric machine includes a rotor winding wound around a rotor core with a gap, rotor winding ends formed by the rotor winding protruding to an end surface of the rotor core in an axial direction, spacers arranged between adjacent rotor winding ends, mountain-shaped winding support portions provided on both surfaces of the spacers and having an apex with an obtuse angle, meandering ventilation paths formed on both surfaces of the spacers by the mountain-shaped winding support portions and wave-shaped winding support portions formed in the meandering ventilation paths along the meandering ventilation paths.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a rotary electric machine used for a turbine power generator and so on, and particularly relates to a rotary electric machine in which ventilation and cooling performance of a rotor is improved. 
       BACKGROUND ART 
       [0002]    In rotor winding ends of a related-art rotary electric machine, a second flow path which penetrates a high-speed flow region and a vortex flow region is provided in a mountain-shaped portion of an insulator forming a cooling air passage for reducing the temperature, thereby eliminating the vortex flow region and making the temperature distribution uniform (for example, refer to Patent Literature 1). 
       CITATION LIST 
     Patent Literature 
       [0003]    Patent Literature 1: JP-A-9-322454 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0004]    In the rotary electric machine having such rotor, the rotor winding ends are cooled by a cooling gas circulating between adjacent coils held by a spacer as an insulator. When the output of the rotary electric machine is increased, there is a problem that the temperature of the rotor is increased to be higher than a heatproof temperature of the insulator with the increase of a field current of the rotor. 
         [0005]    The present invention has been made in view of the above problem, and an object thereof is to obtain a rotary electric machine having a rotor in which an insulation failure does not occur even when the output of the rotary electric machine is increased by improving the cooling performance at the rotor winding ends of the rotor of the rotary electric machine. 
       Solution to Problem 
       [0006]    According to an embodiment of the present invention, there is provided a rotary electric machine including a rotor winding wound around a rotor core with a gap, rotor winding ends formed by the rotor winding protruding to an end surface of the rotor core in an axial direction, spacers arranged between adjacent rotor winding ends, mountain-shaped winding support portions provided on both surfaces of the spacers and having an apex with an obtuse angle, meandering ventilation paths formed on both surfaces of the spacers by the mountain-shaped winding support portions, and wave-shaped winding support portions formed in the meandering ventilation paths along the meandering ventilation paths. 
         [0007]    Also according to an embodiment of the present invention, there is provided a rotary electric machine including a rotor winding wound around a rotor core with a gap, rotor winding ends formed by the rotor winding protruding to an end surface of the rotor core in an axial direction, spacers arranged between adjacent rotor winding ends, arc-shaped winding support portions provided on both surfaces of the spacers, meandering ventilation paths formed on both surfaces of the spacers by the arc-shaped winding support portions and wave-shaped winding support portions formed in the meandering ventilation paths along the meandering ventilation paths and having a shape in which arc-shaped winding support portions are connected. 
       Advantageous Effects of Invention 
       [0008]    When adopting the rotary electric machine according to the present invention, flow separation in the apex of the mountain-shaped winding support portion is suppressed, a vortex flow region behind the mountain-shaped winding support portion is reduced and the cooling gas uniformly flows over the entire meandering ventilation paths, therefore, pressure loss can be drastically reduced. Furthermore, the flow in the meandering ventilation paths formed in the spacers is made to be uniform, thereby suppressing local temperature increase at the rotor winding ends. 
         [0009]    The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is a cross-sectional side view of a turbine generator using a rotary electric machine according to Embodiment 1 of the present invention. 
           [0011]      FIG. 2  is an enlarged cross-sectional view of a relevant part around rotor winding ends in  FIG. 1 . 
           [0012]      FIG. 3  is a perspective view showing a state where a coil retaining ring and an end ring are removed in  FIG. 1 . 
           [0013]      FIG. 4  is a plan view showing a relevant part of the rotor winding ends in  FIG. 1 . 
           [0014]      FIG. 5  is a perspective view showing a spacer of a rotary electric machine according to Embodiment 1 of the present invention. 
           [0015]      FIG. 6  is a side view showing the spacer of the rotary electric machine according to Embodiment 1 of the present invention. 
           [0016]      FIG. 7  is a side view showing a spacer of the rotary electric machine in a comparative example. 
           [0017]      FIG. 8  is a perspective view showing a relevant parts of spacers of the rotary electric machine according to the comparative example. 
           [0018]      FIG. 9  is a side view showing a modification example of the spacer of the rotary electric machine according to Embodiment 1 of the present invention. 
           [0019]      FIG. 10  is a side view showing a spacer of a rotary electric machine according to Embodiment 2 of the present invention. 
           [0020]      FIG. 11  is a side view showing a spacer of a rotary electric machine according to Embodiment 3 of the present invention. 
           [0021]      FIG. 12  is a side view showing a modification example of the spacer of the rotary electric machine according to Embodiment 3 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0022]    Hereinafter, Embodiment 1 of the present invention will be explained with reference to the drawings. 
         [0023]    In respective drawings, the same symbols denote the same or equivalent components. 
       Embodiment 1 
       [0024]      FIG. 1  is a cross-sectional side view of a turbine generator using a rotary electric machine according to Embodiment 1 of the present invention.  FIG. 2  is an enlarged cross-sectional view of a relevant part around rotor winding ends in  FIG. 1 , which is a side view of a region surrounded by a dotted line in  FIG. 1 .  FIG. 3  is a perspective view of the rotor showing a state where a coil retaining ring and an end ring are removed in  FIG. 1  and  FIG. 4  is a plan view showing a relevant part of the rotor winding ends in  FIG. 1  in an exploded manner. 
         [0025]    First, a rotary electric machine  100  will be explained. As shown in  FIG. 1 , the rotary electric machine  100  is configured by coaxially arranging a stator  1  having a hollow cylindrical shape and a rotor  5  having a cylindrical shape a diameter of which is slightly smaller than a diameter of the hollow portion through a gap (air gap)  25 . The stator  1  and the rotor  5  have conductive coils formed of copper respectively arranged in an axial direction of an iron core slot. When the rotor  5  is rotated in a state where the coils on the rotor  5  side are excited, the electric current is induced on the stator  1  side. At this time, large heat caused by electrical loss is generated in the stator  1  or rotor  5 , therefore, particular cooling is required. Accordingly, the rotary electric machine  100  performs forced cooling by installing a fan  26  in the rotor  5  and feeding a cooling gas into the rotary electric machine  100 . As the cooling gas for cooling the inside of the rotary electric machine  100 , gases such as air or hydrogen are used. 
         [0026]    Next, the cooling of the rotary electric machine  100  will be explained. As shown in  FIG. 1 , a turbine generator  200  includes the stator  1 , the rotor  5 , a fan  26  and a cooler  27 . The stator  1  includes a stator core  2 , a stator winding  3  and a duct  4 . The rotor  5  includes a rotor core  6 , a rotor winding  7 , a coil retaining ring  30 , an end ring  31  and a rotating shaft  13 . The rotating shaft  13  is supported by a bearing (not shown) so as to rotate freely, and the fan  26  is symmetrically attached to an end of the rotating shaft  13 . An outer periphery of the rotor core  6  and an inner periphery of the stator core  2  are separated by the gap (air gap)  25 . 
         [0027]    The rotating shaft  13  rotates, the cooling gas pressure-fed by the fan  26  is divided into two ways, and one cooling gas is introduced from an opening  31   a  (see  FIG. 2 ) of the end ring  31  and cools rotor winding ends  8  inside the coil retaining ring  30 , then, the cooling gas is discharged from notch exhaust passages  15  in rotor magnetic poles  14  (see  FIG. 3 ) in a direction of an arrow A 3  into the gap  25 . The other cooling gas cools ends of the stator winding  3  and flows inside the gap  25  in the axial direction, then, the cooling gas joins the cooling gas of the arrow A 3 . Then, the cooling gas flows inside the duct  4  along the arrow A 4  and cools the stator core  2  and the stator winging  3 . After that, the cooling gas flows along an arrow A 5  (see  FIG. 1 ), heat-exchanged by the cooler  27  and is recirculated to an intake side of the fan  26 . 
         [0028]    As shown in  FIG. 3 , the rotor winding  7  is formed of plural field coils in which a plurality of saddle-type rotor coils  11  having a rectangular shape which are formed by concentrated winding respectively around the rotor magnetic pole  14  are coaxially disposed inside plural slots (not shown) arranged in the rotor core  6  on the right and left of respective rotor magnetic fields  14 , which are connected in series. The rotor coil  11  includes coil edges (not shown) inside the slot and the rotor winding ends  8  protruding from end surfaces of the rotor core  6 . The rotor winding end  8  includes a pair of straight line portions  9  protruding from the end surfaces of the rotor core  6  in the direction of the rotating shaft and connection portions  10  connecting both straight line portions  9 . A plurality of rotor winding ends  8  are arranged to protrude at end portions of the rotor magnetic poles  14  at intervals therebetween. 
         [0029]    As shown in  FIG. 2 , the coil retaining ring  30  covers and holds respective outer peripheries of the rotor winding ends  8  and spacers  18  arranged between adjacent the rotor winding ends  8 , and one end is fitted to an end portion of the rotor core  6 . The end ring  31  is fitted to the other end of the coil retaining ring  30 , and the cooling gas for cooling the rotor winding ends  8  is introduced from a space between the opening  31   a  provided to penetrate in the rotating shaft direction and the rotating shaft  13  as shown by the arrow A 1 . In a lower part of the rotor winding ends  8  in the width center of a circumferential direction, a partition plate  20  for gathering the cooling gas flowing in meandering ventilation paths provided in the spacers  18  to cool the rotor winding ends  8  and guiding the gas to the notch exhaust passages  15  as shown by arrows A 2  (see  FIG. 2 ) is provided on the rotating shaft  13 . 
         [0030]    Furthermore,  8   a,    8   b,    8   c  and  8   d  which are the rotor winding ends  8  respectively have  9   a,    9   b,    9   c  and  9   d  which are respectively pairs of straight line portions  9  and  10   a,    10   b,    10   c  and  10   d  which are connection portions  10  as shown in  FIGS. 4 .  16   a ,  16   b  and  16   c  which are respectively spacers  16  are disposed between respective  9   a,    9   b,    9   c  and  9   d  which are the straight line portions  9 .  18   a,    18   b  and  18   c  which are respectively spacers  18  are disposed between respective  10   a,    10   b,    10   c  and  10   d  which are the connection portions  10 . 
         [0031]      17   a,    17   b  and  17   c  which are meandering ventilation paths  17  extending in a meandering manner are provided on both side surface portions of the respective spacers  16   a,    16   b  and  16   c  along a longitudinal direction of side wall surfaces of respective straight line portions  9   a,    9   b,    9   c  and  9   d  on which the spacers  16  abut. Also,  19   a,    19   b  and  19   c  which are meandering ventilation paths  19  extending in a meandering manner are provided on both side surface portions of the respective spacers  18   a,    18   b  and  18   c  along a longitudinal direction of side wall surfaces of respective connecting portions  10   a,    10   b,    10   c  and  10   d  on which the spacers  18  abut. 
         [0032]    In the meandering ventilation paths  17   a,    17   b  and  17   c,  a side wall surface of each of the straight line portions  9   a,    9   b,    9   c  and  9   d  configures one wall surface of each of the meandering ventilation paths  17   a,    17   b  and  17   c.  In the meandering ventilation paths  19   a,    19   b  and  19   c,  a side wall surface of each of the connecting portions  10   a,    10   b,    10   c  and  10   d  configures one wall surface of each of the meandering ventilation paths  19   a,    19   b  and  19   c.    
         [0033]    The partition plate  20  is configured so that a lower part is inserted into a groove (not shown) of the rotating shaft  13  (see  FIG. 2 ), including a pair of side plates  20   a  one-side end surface of which abuts on the side wall of the rotor magnetic pole  14  and an endplate  20   b  bonded to the other side end surfaces of the pair of side plates  20   a  and arranged in the opening  31   a  (see  FIG. 2 ) of the end ring  31 . 
         [0034]    Here, the spacers  16  will be briefly explained with reference to  FIG. 4 . On both end surface portions of respective spacers  16   a,    18   a,  meandering grooves  21  (not shown) meandering and extending toward the longitudinal direction of respective spacers  16   a,    18   a  are formed. Then, the spacer  16   a  is arranged between the straight line portions  9   a  and  9   b  and the spacer  18   a  is arranged between the connecting portions  10   a  and  10   b  respectively to be assembled. The meandering ventilation path  17   a  is formed by the meandering groove  21  (not shown) of the spacer  16   a  and the side wall surfaces of the straight line portions  9   a,    9   b.  The meandering ventilation path  19   a  is formed by the meandering groove  21  of the spacer  18   a  and the side wall surfaces of the connecting portions  10   a,    10   b.  The introduced cooling gas cools the straight line portions  9   a,    9   b  and the connecting portions  10   a,    10   b  while continuously flowing inside respective meandering ventilation paths  17   a,    19   a  as shown in the arrow A 2 , which is guided to a space surrounded by right and left side plates  20   a  of the partition plate  20 . 
         [0035]    As shown in  FIG. 4 , the cooling gas in the rotor winding ends  8  is introduced from the opening  31   a  (see  FIG. 2 ) of the end ring  31  as shown in the arrow A 1 , then, introduced into the meandering ventilation paths  17   a,    17   b  and  17   c  on both sides of respective spacers  16   a,    16   b  and  16   c  and continuously flows from the meandering ventilation paths  17   a,    17   b  and  17   c  toward the direction of the arrow A 2  representatively shown by a long dashed and short dashed line as the arrow A 2  into the meandering ventilation paths  19   a,    19   b  and  19   c  on both sides of respective spacers  18   a,    18   b  and  18   c.  Then, the flows from the right and left meandering ventilation paths  19   a,    19   b  and  19   c  join (not shown) at the central part, flowing in the space surrounded by the right and left side plates  20   a  of the partition plate  20  toward the direction of the rotating shaft and guided to the notch discharge path  15 . 
         [0036]    As described above, the electrical resistance loss in the  8   a,    8   b,    8   c  and  8   d  which are the rotor winding ends  8  is absorbed by the cooling gas flowing through the meandering ventilation paths  17   a,    17   b,    17   c,    19   a,    19   b  and  19   c,  which suppresses the temperature increase of the rotor winding ends  8 . 
         [0037]      FIG. 5  is a perspective view showing a spacer of a rotary electric machine according to Embodiment 1 of the present invention.  FIG. 5  shows a state where the coil retaining ring is removed. The spacer  16   a  includes mountain-shaped winding support portions  41  and a wave-shaped winding support portion  42  inside the meandering ventilation path  17   a.  FIG.  6  is a side view showing the spacer of the rotary electric machine according to Embodiment 1 of the invention. Here, an apex angle  47  of the mountain-shaped winding support portions  41  is an obtuse angle. 
         [0038]    As shown in  FIG. 5  and  FIG. 6 , a cooling gas  48  flowing into the meandering ventilation path  17   a  provided in the spacer  16   a  is divided into two ways at an end of the wave-shaped winding support portion  42  . As the apex angle  47  of the mountain-shaped winding support portion  41  is the obtuse angle in Embodiment 1, flow separation in the apex of the mountain-shaped winding support portion  41  is suppressed, and the cooling gas uniformly flows over the entire meandering flow path without causing a vortex flow region generated behind the mountain-shaped winding support portion  41 . 
         [0039]      FIG. 7  is a side view showing a state of the spacer of the rotary electric machine in a comparative example. As shown in  FIG. 7 , the rotor windings  7  normally having several millimeters in thickness are stacked in a vertical direction in the drawing, therefore, it is necessary to set a mountain height  46  of the mountain-shaped winding support portion  41  to be equal to or larger than the half width of a width  45  of the spacer and to support the rotor winding  7  as the coil at least at one point for maintaining a retaining force of the rotor winding  7  by the spacer  16   a  over the entire area. Accordingly, the apex angle of the mountain-shaped winding support portion  41  is normally an acute angle and the flow of the cooling gas  48  flowing in the meandering ventilation path  17   a  is separated at the apex of the mountain-shaped winding support portion  41 , which causes a vortex flow region  49  where the flow is stagnant behind the mountain-shaped winding support portion  41 . Due to the existence of the vortex region  49 , a cross-sectional area of the flow path in which the cooling gas  48  actually flows is reduced, and a high-speed flow region where the flow rate is increased is generated. As a result, pressure loss of the ventilation path is increased. Additionally, the vortex flow region  49  will be a heat-insulating layer in which heat exchange between the rotor winding ends  8  and the cooling gas  48  is suppressed. Accordingly, the rotor winding ends  8  contacting the vortex flow region  49  are increased in temperature as compared with the rotor winding ends  8  contacting the high-speed flow region. 
         [0040]      FIG. 8  is a perspective view showing relevant parts of spacers of a rotary electric machine according to a comparative example. Also in the spacer  16   a  in the comparative example, the meandering grooves  21  having the same groove depth Di and the width W, meandering and extending toward the longitudinal direction of respective spacers  16   a,    18   a  are formed on both side surface portions of respective spacers  16   a,    18   a  in the same manner as Embodiment 1. Then, the spacer  16   a  is arranged between straight line portions  9   a,    9   b  and the spacers  18   a  is arranged between the connecting portions  10   a,    10   b  respectively to be assembled. The meandering ventilation path  17   a  is formed by the meandering groove  21  (not shown) of the spacer  16   a  and the side wall surfaces of the straight line portions  9   a,    9   b.  The meandering ventilation path  19   a  is formed by the meandering groove  21  of the spacer  18   a  and the side wall surfaces of the connecting portions  10   a,    10   b.  The introduced cooling gas cools the straight line portions  9   a,    9   b  and the connecting portions  10   a,    10   b  while continuously flowing inside respective meandering ventilation paths  17   a,    19   a  as shown in the arrow A 2 , which is introduced to a space surrounded by right and left side plates  20   a  of the partition plate  20 . 
         [0041]    According to Embodiment 1 of the present invention, the cross-sectional area of the flow path through which the refrigerant actually flows is increased as compared with the structure of the comparative example, therefore, the flow rate is reduced, which can drastically reduce pressure loss proportional to a square of the flow rate. Furthermore, the flow in the meandering ventilation path  17   a  formed by the spacer  16   a  is made to be uniform, thereby suppressing the local temperature increase in the rotor winding ends  8 . 
         [0042]    The shape of the mountain-shaped winding support portions  41  is not limited to a triangular shape but may be a trapezoid shape (not shown). The shape of the mountain-shaped winding support portions  41  of the spacer  16   a  may also be an arc shape as shown in  FIG. 9 . In this case, the shape of the wave-shaped winding support portion  42  is preferably a shape in which arcs are connected, and respective meandering ventilation paths  17   a  separated by the wave-shaped winding support portion  42  preferably have almost the same cross-sectional area in the flowing direction. 
       Embodiment 2 
       [0043]      FIG. 10  is a side view showing a spacer of a rotary electric machine according to Embodiment 2 of the present invention. The spacer  16   a  includes mountain-shaped winding support portions  41  and the wave-shaped winding support portion  42  in the meandering ventilation path  17   a.  Here, the mountain height  46  of the mountain-shaped winding support portion  41  is ⅓ or more as well as ½ or less of the width  45  of the spacers, and the apex angle  47  is an obtuse angle. Accordingly, the apex of the mountain-shaped winding support portion  41  and a valley portion of the wave-shaped winding support portion have an overlapping region  43  in a circumferential direction. 
         [0044]    Accordingly, in addition to the effect obtained in Embodiment 1, the retaining force of the stacked rotor winding ends  8  is increased as the overlapping region  43  is included. 
         [0045]    The shape of the mountain-shaped winding support portions  41  is not limited to a triangular shape but may be a trapezoid shape. The shape of the mountain-shaped winding support portions  41  may also be an arc shape. 
       Embodiment 3 
       [0046]      FIG. 11  is a side view showing a spacer of a rotary electric machine according to Embodiment 3 of the present invention. In Embodiment 3, the spacer  16   a  includes mountain-shaped winding support portions  41  and the wave-shaped winding support portion  42  provided in the meandering ventilation path  17   a.  On a cooling gas inflow port  50  side, the wave-shaped winding support portion  42  has an end portion  44  extending to the vicinity of the center of the cooling gas inflow port  50 . 
         [0047]    Accordingly, in Embodiment 3, the flow rate of the gas flowing right and left sides of the wave-shaped winding support portion  42  can be adjusted to be uniform by the protruding length of the end portion  44  of the wave-shaped winding support portion  42 , in addition to the effects obtained in Embodiment 1 and Embodiment 2. Therefore, the local temperature distribution in the rotor winding ends  8  can be further suppressed. 
         [0048]      FIG. 12  is a side view showing a modification example of the spacer of the rotary electric machine according to Embodiment 3 of the present invention. As shown in  FIG. 12 , the spacer  16   a  includes mountain-shaped winding support portions  41  and the wave-shaped winding support portion  42  provided in the meandering ventilation path  17   a.  The wave-shaped winding support portion  42  may also have a structure in which the end portion  44  extends toward the cooling gas inflow port  50 . 
         [0049]    Accordingly, also in the modification example of Embodiment 3, the flow rate of the gas flowing right and left sides of the wave-shaped winding support portion  42  can be adjusted to be uniform by the protruding length of the end portion  44  of the wave-shaped winding support portion  42 , in addition to the effects obtained in Embodiment 1 and Embodiment 2. Therefore, the local temperature distribution in the rotor winding ends  8  can be further suppressed. 
         [0050]    In any of these embodiments, the explanation has been made on the assumption that the number of the winding support portion  42  in the meandering ventilation path  17   a  is one, however, two or more wave-shaped winding support portions  42  maybe provided in parallel. Although the spacer  16   a  provided in the straight line portion  9  has been explained in Embodiment 1 to Embodiment 3, it is possible to apply Embodiment 1 to Embodiment 3 of the present invention to the arc-shaped spacer  18   a  provided in the connecting portion  10  in the same manner. Furthermore, the rotary electric machine having the ventilation paths has been representatively explained in the present invention, however, the present invention can be applied to spacers of other rotary electric machines having ventilation paths. 
         [0051]    In the present invention, respective embodiments can be freely combined, and respective embodiments can be suitably modified or omitted within a scope of the invention. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  . . . stator,  2  . . . stator core,  3  . . . stator winding,  4  . . . duct,  5  . . . rotor,  6  . . . rotor core,  7  . . . rotor winding,  8 ,  8   a,    8   b,    8   c,    8   d  . . . rotor winding end,  9 ,  9   a,    9   b,    9   d  . . . straight line portion,  10 ,  10   a,    10   b,    10   c,    10   d  . . . connection portion,  11  . . . rotor coil,  13  . . . rotating shaft,  14  . . . rotor magnetic pole,  15  . . . notch exhaust passage,  16 ,  16   a,    16   b,    16   c  . . . spacer,  17 ,  17   a,    17   b,    17   c  . . . meandering ventilation path,  18 ,  18   a,    18   b,    18   c  . . . spacer,  19 ,  19   a,    19   b,    19   c  . . . meandering ventilation path,  20  . . . partition plate,  21  . . . meandering groove,  25  . . . gap,  26  . . . fan,  27  . . . cooler,  30  . . . coil retaining ring,  31  . . . end ring,  41  . . . mountain-shaped winding support portion,  42  . . . wave-shaped winding support portion,  47  . . . apex,  48  . . . cooling gas,  50  . . . cooling gas inflow port