Patent Publication Number: US-11025136-B2

Title: Dynamo-electric machine

Description:
TECHNICAL FIELD 
     The present invention relates to a dynamo-electric machine such as a generator and an electric motor. 
     BACKGROUND ART 
     In a dynamo-electric machine such as a large-sized generator and a large-sized electric motor for which high output (high power) and high speed rotation are required, since a thick high-voltage insulating paper is used at an inside of a stator and a winding portion such as a coil end in response to the high output and also a magnet of a rotor is fixed to a rotation shaft with the magnet being surrounded with a ring in response to the high speed rotation, there is a tendency for the winding portion of the stator and a magnet portion of the rotor not to easily radiate or release heat, then this causes an increase in temperature. 
     For this problem, for instance, the following Patent Document 1 has proposed that the stator and the rotor should be cooled by providing a water-cooling jacket between a frame and the stator, forming a ventilation path between the water-cooling jacket and the frame, making cooling water flow in the water-cooling jacket and making air inside the frame circulate through the ventilation path. 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-211816 
         Patent Document 2: Japanese Unexamined Patent Application Publication No. 2008-301646 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     According to demands for an even higher output and an even higher speed rotation, further improvement in cooling performance has been strongly required for such large-sized dynamo-electric machine described above. 
     Solution to Problem 
     In order to meet the above demands, a dynamo-electric machine of the present invention comprises: a cylindrical frame; a cylindrical stator fixed to an inside of the frame; a cylindrical rotor provided inside the stator such that a gap is formed between the rotor and the stator; a rotation shaft fixed to the rotor so as to penetrate an inside of the rotor; and a bracket fixed to the frame and rotatably supporting the rotation shaft, wherein the stator has a duct radially formed at a middle portion in an axial direction of the stator and communicating with the gap, and the frame has a first supply opening through which cooling air flow is supplied in the frame at axial direction both end sides of the frame, an exhaust opening through which cooling air flow in the frame is exhausted to an outside of the frame and a second supply opening through which cooling air flow is supplied to the duct of the stator. 
     The dynamo-electric machine of the present invention further comprises: cooling-water pipes provided as a pair at one end side and the other end side of a middle in the axial direction of the frame, wherein the cooling-water pipes has, at the middle in the axial direction of the frame, inlets through which cooling water is supplied to the cooling-water pipes and has, at the axial direction both end sides of the frame, outlets through which the cooling water is exhausted from the cooling-water pipes. 
     In the dynamo-electric machine of the present invention, the frame is an aluminum metal-made frame having the cooling-water pipes between an outer peripheral surface and an inner peripheral surface of the frame by casting. 
     Effects of Invention 
     When supplying the cooling air flow into the first and second supply openings of the dynamo-electric machine of the present invention, the cooling air flow supplied from the first supply opening flows to the both end sides in the axial direction in the frame while cooling coil ends etc., and is exhausted to the outside of the frame from the exhaust opening. The cooling air flow supplied from the second supply opening flows in the duct of the stator while cooling the stator from the middle portion in the axial direction of the stator, and reaches the gap. This cooling air flow branches off from the axial direction middle portion, further flows in the gap toward the both end sides of the frame while cooling an inner peripheral surface of the stator and an outer peripheral surface of the rotor, flows out from the gap, and is exhausted to the outside of the frame from the exhaust opening. 
     Therefore, according to the dynamo-electric machine of the present invention, not only the coil ends can be cooled, but also an inside of the axial direction middle portion of the stator, which is highest in temperature at the stator, can be air-cooled from a radial direction outer side to a radial direction inner side, and further the inner peripheral surface of the stator and an outer peripheral surface of the rotor can be air-cooled from the axial direction middle portion to the both end sides. Hence, even in a case where a thick high-voltage insulating paper is used at the inside of the stator and winding portions such as the coil ends in response to the high output and also the rotor is fixed to the rotation shaft with a permanent magnet being surrounded with a ring in response to the high speed rotation, the inside of the stator, the winding portions such as the coil ends and the permanent magnet of the rotor are effectively cooled, and the temperature increase can be greatly suppressed. 
     Accordingly, according to the dynamo-electric machine of the present invention, the cooling performance is further improved, and even higher output and even higher speed rotation can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an external view of a main part of a dynamo-electric machine according to a main embodiment of the present invention. 
         FIG. 2  is a schematic sectional view of the dynamo-electric machine shown in  FIG. 1 . 
         FIG. 3  is a drawing showing structures of cooling-water pipes of the dynamo-electric machine shown in  FIGS. 1 and 2 . 
         FIG. 4  is a drawing for explaining supply and exhaust directions of cooling water and cooling air flow of the dynamo-electric machine shown in  FIG. 1 . 
         FIG. 5  is a drawing for explaining flow directions of the cooling air flow of the dynamo-electric machine shown in  FIG. 2 . 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     An embodiment of a dynamo-electric machine according to the present invention will be explained below with reference to the drawings. However, the present invention is not limited to the following embodiment explained using the drawings. 
     Main Embodiment 
     A main embodiment of the dynamo-electric machine according to the present invention will be explained with reference to  FIGS. 1 to 5 . 
     As shown in  FIGS. 1 and 2 , an outer peripheral surface of a cylindrical stator  12  is fixed to an inner peripheral surface at a middle in an axial direction of a cylindrical hollow-shaped frame  11  made of aluminum metal, which is high heat transfer material, so that the stator  12  is coaxial with the frame  11 . Further, a rotation shaft  14  is provided so as to penetrate an inside of the stator  12  and be coaxial with the stator  12 . The rotation shaft  14  is rotatably supported, at both end sides thereof, by a pair of annular brackets  15  that are fixed to both end sides of the frame  11 . 
     A permanent magnet  13   a  is provided on an outer peripheral surface at a middle in the axial direction of the rotation shaft  14  throughout an entire circumference of the rotation shaft  14  so as to face an inner peripheral surface of the stator  12 . Further, a cylindrical ring  13   b  that is made of iron or the like having magnetism is fitted so as to fix the permanent magnet  13   a  on the outer peripheral surface of the rotation shaft  14 . The permanent magnet  13   a  and the ring  13   b  etc. form a rotor  13 . In other words, the rotation shaft  14  is fixed to the rotor  13  so as to penetrate an inside of the rotor  13 . The rotor  13  is provided inside the stator  12  such that a gap G having a specified distance is formed between the inner peripheral surface of the stator  12  and an outer peripheral surface of the ring  13   b.    
     At both end sides in the axial direction on a peripheral surface of the frame  11 , first supply openings  16  and exhaust openings  18  through which an inside and an outside of the frame  11  communicate with each other are formed so as to face each other. At a middle in the axial direction on the peripheral surface of the frame  11 , a plurality of second supply openings (in the present embodiment, two second supply openings)  17  through which ducts  12   a  that are radially formed at a middle portion in the axial direction of the stator  12  and that communicate with the gap G and the outside of the frame  11  communicate with each other are formed at regular intervals along a circumferential direction of the frame  11 . 
     Further, at a middle in the axial direction between an outer peripheral surface and an inner peripheral surface of the frame  11 , helical stainless (SUS) cooling-water pipes  21 A and  21 B (see  FIG. 3 ) are formed by casting such that these cooling-water pipes  21 A and  21 B are arranged as a pair at one end side and the other end side of the middle of the frame  11 . The cooling-water pipes  21 A and  21 B have inlets  21 Aa and  21 Ba respectively that are exposed to the outside of the frame  11  at lower positions at the middle in the axial direction of the frame  11 . The cooling-water pipes  21 A and  21 B also have outlets  21 Ab and  21 Bb respectively that are exposed to the outside of the frame  11  at upper positions at the both end sides in the axial direction of the frame  11 . 
     In the drawing, reference signs  19  denote coil ends. 
     In such dynamo-electric machine  10  of the present embodiment, as depicted in  FIG. 4 , cooling air flows  1  are supplied into the frame  11  from the first and second supply openings  16  and  17 , and cooling waters  2  are supplied to the cooling-water pipes  21 A and  21 B from the inlets  21 Aa and  21 Ba. 
     Then, as depicted in  FIG. 5 , the cooling air flows  1  supplied from the first supply openings  16  flow to the both end sides in the axial direction in the frame  11  while cooling the coil ends  19  etc., and are exhausted to the outside of the frame  11  from the exhaust openings  18 . The cooling air flows  1  supplied from the second supply openings  17  flow in the ducts  12   a  of the stator  12  while cooling the stator  12  from the middle portion in the axial direction of the stator  12 , and reach the gap G. These cooling air flows  1  branch off from the axial direction middle portion, and further flow in the gap G toward the both end sides of the frame  11  while cooling the inner peripheral surface of the stator  12  and an outer peripheral surface of the rotor  13 . The cooling air flows  1  flowing out from the gap G join or meet the cooling air flows  1  supplied from the first supply openings  16 , and are exhausted to the outside of the frame  11  from the exhaust openings  18 . 
     On the other hand, the cooling waters  2  supplied from the inlets  21 Aa and  21 Ba flow in the cooling-water pipes  21 A and  21 B. That is, the cooling waters  2  cool almost all the stator  12  from an outer peripheral surface of the stator  12  through the frame  11  while helically flowing on the outer peripheral surface of the stator  12  from the axial direction middle to the both end sides of the stator  12 , and are exhausted from the outlets  21 Ab and  21 Bb. 
     That is to say, in the dynamo-electric machine  10  according to the present embodiment, not only the coil ends  19  are cooled by the cooling air flows  1  supplied from the first supply openings  16 , but also an inside of the axial direction middle portion of the stator  12 , which is highest in temperature at the stator  12 , is air-cooled from a radial direction outer side to a radial direction inner side by the cooling air flows  1  supplied from the second supply openings  17 , and further the inner peripheral surface of the stator  12  and an outer peripheral surface of the rotor  13  are air-cooled from the axial direction middle portion to the both end sides by the cooling air flows  1  supplied from the second supply openings  17 . Moreover, by the cooling waters  2  supplied from the inlets  21 Aa and  21 Ba, the outer peripheral surface of the stator  12  is water-cooled from the axial direction middle portion of the stator  12 , which is highest in temperature at the stator  12 , to the both end sides of the stator  12 . 
     Hence, in the dynamo-electric machine  10  of the present embodiment, even in a case where a thick high-voltage insulating paper is used at the inside of the stator  12  and winding portions such as the coil ends  19  in response to the high output and also the rotor  13  is fixed to the rotation shaft  14  with the permanent magnet  13   a  being surrounded with the ring  13   b  in response to the high speed rotation, the inside of the stator  12 , the winding portions such as the coil ends  19  and the permanent magnet  13   a  of the rotor  13  are effectively cooled, and the temperature increase can be greatly suppressed. 
     Accordingly, according to the dynamo-electric machine  10  of the present embodiment, since cooling performance can be greatly improved, even higher output and even higher speed rotation can be achieved. 
     Further, since the stator  12  is cooled by the cooling waters  2  flowing parallel in the two cooling-water pipes  21 A and  21 B, a quantity of flow (or a flow rate) per unit time of the cooling water  2  can be increased without increasing pressure loss in the cooling-water pipes  21 A and  21 B Therefore, cooling performance by the cooling water  2  can be greatly improved. 
     INDUSTRIAL APPLICABILITY 
     The dynamo-electric machine according to the present invention is capable of achieving even higher output and even higher speed rotation by greatly improving the cooling performance. Therefore, the dynamo-electric machine of the present invention can be effectively utilized in industry. 
     EXPLANATION OF REFERENCE 
     
         
           1  . . . cooling air flow,  2  . . . cooling water,  10  . . . dynamo-electric machine,  11  . . . frame,  12  . . . stator,  12   a  . . . duct,  13  . . . rotor,  13   a  . . . permanent magnet,  13   b  . . . ring,  14  . . . rotation shaft,  15  . . . bracket,  16  . . . first supply opening,  17  . . . second supply opening,  18  . . . exhaust opening,  19  . . . coil end,  21 A,  21 B . . . cooling-water pipe,  21 Aa,  21 Ba . . . inlet,  21 Ab,  21 Bb . . . outlet, G . . . gap