Patent Publication Number: US-2022239205-A1

Title: Method for assembling large-diameter electric motor

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to Chinese Patent Application No. 201910436358.1, titled “METHOD FOR ASSEMBLING LARGE-DIAMETER ELECTRIC MOTOR” and filed on May 23, 2019, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a technical filed of electric motors, and particularly relates to a method for assembling a large-diameter electric motor. 
     BACKGROUND 
     As a single-machine power of a wind-power electric generator set becomes larger and larger, an outer diameter of an electric motor becomes larger and larger. If the outer diameter of the large-diameter electric motor is greater than 5 m, it will exceed the road transportation limiting value; if a dimension of the outer diameter is larger than 4.2 m, the transportation cost will increase sharply, which will bring great challenges to the land transportation. 
     At present, the effective solution is usually to divide the large-diameter electric motor into two or more electric motor separating portions in the circumferential direction, and after the electric motor separating portions are all transported to a site, the electric motor separating portions are assembled into a whole electric motor on the site. However, there is a large magnetic pulling force at an air gap between a stator and a rotor of the large-diameter electric motor, resulting in increasing the complexity of an assembling process. 
     SUMMARY 
     The object of the present disclosure is to provide a method for assembling a large-diameter electric motor; the method can avoid the influence of a magnetic pulling force at an air gap between a stator and a rotor on an assembling process. 
     Thus, the method for assembling the large-diameter electric motor is provided by the present disclosure; the method includes: a preparing step: providing two or more stator segments for forming the stator and two or more rotor support segments for forming a rotor support; a splicing step: splicing the two or more stator segments and the two or more rotor support segments in a predetermined manner to form the stator and the rotor support that are coaxially assembled, respectively, and maintaining a predetermined gap between the stator and the rotor support in a radial direction; and an assembling step: inserting a plurality of magnetic pole modules into the predetermined gap, and assembling the plurality of magnetic pole modules to a mounting surface of the rotor support. 
     The method for assembling the large-diameter electric motor is provided by the present disclosure. After two or more stator segments and two or more rotor support segments assembled into the complete stator and the complete rotor support respectively and a predetermined gap is maintained between the stator and the rotor support in the radial direction, the plurality of magnetic pole modules are assembled to the mounting surface of the rotor support through the predetermined gap, so that the influence of the magnetic pulling force at the air gap between the stator and a rotor on an assembling process can be avoided, and the convenience of assembling the large-diameter electric motor can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure can be better understood from the following description of the specific embodiments of the present disclosure in conjunction with the drawings; herein, by reading the following detailed description of the non-limiting embodiments with reference to the drawings, other features, objects, and advantages of the present disclosure will become more apparent, and the same or similar reference signs indicate the same or similar features. 
         FIG. 1  shows a flowchart of a method for assembling a large-diameter electric motor according to an embodiment of the present disclosure; 
         FIG. 2  shows a schematic structural view of the large-diameter electric motor in the method for assembling the large-diameter electric motor shown in  FIG. 1 ; 
         FIG. 3  shows a longitudinal-section schematic structural view of the large-diameter electric motor shown in  FIG. 2 ; 
         FIG. 4  shows a schematic structural view of another large-diameter electric motor in the method for assembling the large-diameter electric motor shown in  FIG. 1 ; 
         FIG. 5  shows a schematic top view of a pre-assembled module in the large-diameter electric motor shown in  FIG. 4 ; 
         FIG. 6  shows a schematic structural view of a magnetic pole module in the large-diameter electric motor shown in  FIG. 2 ; 
         FIG. 7  shows a schematic structural view of the magnetic pole module shown in  FIG. 6  in a direction A-A; 
         FIG. 8  shows an assembling effect schematic view of the magnetic pole module and a rotor support shown in  FIG. 6 ; 
         FIG. 9  shows an assembling effect schematic view of an assembling process of a magnetic pole module and a rotor support of a large-diameter electric motor according to an embodiment of the present disclosure. 
     
    
    
     In the drawings:
           1 —stator;  2 —rotor;  3 —magnetic pole module;  31 —base plate;  32 —magnetic steel;  311 —connecting portion;  2   a —mounting surface;  4 —main shaft;  41 —fixing shaft;  411 —first outer flange plate;  42 —rotating shaft;  421 —second outer flange plate;  43 —bearing;  5 —pressing strip;  6 —fastening member;  7 —fixing member;     10 —stator segment;  20 —rotor support segment.       

     DETAILED DESCRIPTION 
     The features and exemplary embodiments of various aspects of the present disclosure will be described in detail below. Many specific details are disclosed in the following detailed description in order to fully understand the present disclosure. However, it is obvious to those skilled in the art that the present disclosure can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present disclosure by showing examples of the present disclosure. The present disclosure is by no means limited to any specific configurations and algorithms proposed below, but covers any modification, replacement and improvement of elements, member and algorithms without departing from the spirit of the present disclosure. In the drawings and the following description, well-known structures and technologies are not shown in order to avoid unnecessary obscurity of the present disclosure. 
     In order to better understand the present disclosure, a method for assembling a large-diameter electric motor provided by some embodiments of the present disclosure will be described in detail below in conjunction with  FIG. 1  to  FIG. 9 . 
     Referring to  FIG. 1  and  FIG. 2  together, the method for assembling the large-diameter electric motor is provided by some embodiments of the present disclosure; the method includes 
     a preparing step S 1 : providing two or more stator segments  10  for forming a stator  1  and two or more rotor support segments  20  for forming a rotor support  1 ; 
     in which the stator  1  is divided into two or more stator segments  10 , and the rotor support  2  is divided into two or more rotor support segments  20 , so that each of a dimension of a maximum chord length of each of the stator segments  10  and a dimension of a maximum chord length of each of the rotor support segments  20  is smaller than a road transportation limiting value, so that it is convenient for transportation; in addition, the number of the stator segments  10  may be the same as or different from the number of the rotor support segments  20 ; for example, three stator segments  10  form the complete stator  1 , and two rotor support segments  20  form the complete rotor support  2 ; 
     a splicing step S 2 : splicing the two or more stator segments  10  and the two or more rotor support segments in a predetermined manner to form the stator  1  and the rotor support  2  that are coaxially assembled, respectively, and maintaining a predetermined gap between the stator  1  and the rotor support  2  in a radial direction; in which the large-diameter electric motor can have a structure with an inner stator and an outer rotor, or a structure with an outer stator and an inner rotor; and 
     an assembling step S 3 : inserting a plurality of magnetic pole modules  3  into the predetermined gap, and assembling the plurality of magnetic pole modules  3  to a mounting surface  2   a  of the rotor support  2 ; 
     in which after the magnetic pole modules  3  are mounted on the mounting surface  2   a  of the rotor support  2 , the rotor can be formed; at this time, since the predetermined gap has been maintained between the stator  1  and the rotor support  2  in the radial direction, during the process of assembling the magnetic pole modules  3  to the mounting surface  2   a  of the rotor support  2 , a magnetic pulling force of the magnetic pole modules  3  will not affect a radial distance between the stator  1  and the rotor support  2 , thereby increasing the uniformity of an air gap between the magnetic pole modules  3  of the stator  1  and a rotor. 
     In the method for assembling the large-diameter electric motor provided by the embodiments of the present disclosure, since two or more stator segments  10  and two or more rotor support segments  20  are assembled into the complete stator  1  and the complete rotor support  2  respectively after transported to a site, and the predetermined gap is maintained between the stator and the rotor support in the radial direction, the plurality of magnetic pole modules  3  are inserted into the predetermined gap and assembled to the mounting surface of the rotor support, so that the influence of the magnetic pulling force at the air gap between the stator  1  and the rotor on an assembling process can be avoided, and the convenience of assembling the large-diameter electric motor on site can be improved. 
     A specific process of the method for assembling the large-diameter electric motor provided by the embodiments of the present disclosure will be described in detail below in conjunction with the drawings. 
     As an optional embodiment, the method for assembling the large-diameter electric motor provided by the embodiments of the present disclosure further includes: 
     step S 01 : dividing the stator  1  into two or more stator segments  10  in a circumferential direction; 
     in which the large-diameter stator  1  can be cut into two or more stator segments  10  by means of laser cutting or the like after being manufactured in a processing site, so that the dimension of the maximum chord length of each of the stator segments  10  is smaller than the road transportation limiting value, so that it is convenient for transportation; two or more stator segments  10  are transported from the processing site to an assembling site by means of transportation tools; and 
     step S 02 : dividing the rotor support  2  into two or more rotor support segments  20  in the circumferential direction; 
     in which the large-diameter rotor support  2  can be cut into two or more rotor support segments  20  by means of laser cutting or the like after being manufactured in the processing site, so that the dimension of the maximum chord length of each of the rotor support segments  20  is smaller than the road transportation limiting value, so that it is convenient for transportation; two or more rotor support segments  20  are transported from the processing site to the assembling site by means of transportation tools. 
     Herein, the number of the stator segments  10  and the number of the rotor support segments  20  may be the same or different. 
     It can be understood that an order of executing step S 01  and step S 02  is in no particular order, and can also be performed synchronously. 
     Further, in the splicing step S 2 , the splicing the two or more stator segments  10  and the two or more rotor support segments  20  in the predetermined manner to form the stator  1  and the rotor support  2  that are coaxially assembled respectively includes 
     step S 21 : assembling two or more stator segments  10  into the complete stator  1  in the circumferential direction; 
     in which each of the stator segments  10  has an arc-shaped structure; each of stator segments  10  can be provided with positioning pins or positioning holes on end faces at two ends in the circumferential direction respectively; the positioning holes or the positioning pins are correspondingly arranged on the end faces of the two adjacent stator segments  10  in the circumferential direction, and two or more stator segments  10  can be positioned in the circumferential direction through the cooperation of the positioning holes and the positioning pins; in addition, positioning members can be arranged on the end faces of the two adjacent stator segments  10  in an axial direction, and the two adjacent stator segments  10  can be fixed as a whole in the circumferential direction by the positioning members, thereby assembling the complete stator  1 ; 
     step S 22 : assembling two or more rotor support segments  20  into the complete rotor support  2  in the circumferential direction; 
     in which, similar to the stator segments  10 , each of the rotor support segments  20  has the arc-shaped structure; each of rotor support segments  20  can be provided with positioning pins or positioning holes on end faces at two ends in the circumferential direction respectively; the positioning holes or the positioning pins are correspondingly arranged on the end faces of the two adjacent rotor support segments  20  in the circumferential direction, and two or more rotor support segments  20  can be positioned in the circumferential direction through the cooperation of the positioning holes and the positioning pins; in addition, positioning members can be arranged on the end faces of the two adjacent rotor support segments  20  in the axial direction, and the two adjacent stator segments  10  can be fixed as a whole in the circumferential direction by the positioning members, thereby assembling the complete rotor support  2 ; and 
     step S 23 : assembling the stator  1  and the rotor support  2  coaxially;
         in which the rotor support  2  can sleeve at an outer peripheral side of the stator  1 , or the stator  1  can sleeve on an outer peripheral side of the rotor support  2 .       

     In addition, since there may be a gap between two adjacent rotor support segments  20  or between two adjacent stator segments  10  in the circumferential direction due to assembly errors, an elastic sealing member, such as an O-shaped ring sealing member or the like, can be placed in the gap. 
     It can be understood that an order of executing step S 21  and step S 22  is in no particular order, and can also be performed synchronously. 
     Referring to  FIG. 3 , in the step S 23 , the assembling the stator  1  and the rotor support  2  coaxially includes 
     step S 231 : providing a main shaft  4 , in which the main shaft  4  includes a fixing shaft  41  and a rotating shaft  42  that are arranged coaxially, and a bearing  43  arranged between the fixing shaft  41  and the rotating shaft  42 ; herein, the rotating shaft  42  may sleeve on an outer peripheral side of the fixing shaft  41 , or the fixing shaft  41  may sleeve on an outer peripheral side of the rotating shaft  42 , depending on the specific application occasion; 
     the fixing shaft  41  and the rotating shaft  42  are usually made of a steel material, such as a low carbon steel, a ductile iron or the like, by a forming process, such as welding, casting or the like, and then by a machining process; by fixing components of the bearing  43 , such as a bearing retainer ring and the like, the rotating shaft  42  cannot move in the axial direction relative to the fixing shaft  41 , but can rotate. 
     step S 232 : fixing the stator  1  to the fixing shaft  41 ; 
     in which a first outer flange plate  411  is arranged at the outer circumference of the fixing shaft  41 , and a first inner flange plate (not shown in the drawings) is arranged at an inner circumference of the stator  1 ; the fixing shaft  41  is extended into the inner circumference of the stator  1  in the axial direction, and the first outer flange plate  411  and the first inner flange plate are assembled into an integral body by a fastening member, so as to fix the stator  1  to the fixing shaft  41 ; and 
     step S 233 : fixing the rotor support  2  to the rotating shaft  42  so that the rotor support  2  sleeves on the outer peripheral side of the stator  1 , or the stator  1  sleeves on the outer peripheral side of the rotor support  2 ; 
     in which taking the rotating shaft  42  sleeving on the outer peripheral side of the fixing shaft  41  as an example, a second outer flange plate  421  is arranged at the outer circumference of the rotating shaft  42 , a second inner flange plate (not shown in the drawings) is arranged at an inner circumference of the rotor support  2 , the rotating shaft  42  is extended into the inner circumference of the rotor support  2  in the axial direction, and the second outer flange plate  421  and the second inner flange plate are assembled into an integral body by the fastening member, so as to fix the rotor support  2  to the rotating shaft  42 . 
     As an optional embodiment, the method for assembling the large-diameter electric motor provided by the embodiment of the present disclosure further includes 
     step S 01 : dividing the stator  1  into two or more stator segments  10  in the circumferential direction; 
     step S 02 : dividing the rotor support  2  into two or more rotor support segments  20  in the circumferential direction; and 
     step S 03 : coaxially assembling the stator segments  10  and the rotor support segments  20  into pre-assembled modules  100 . 
     Optionally, the number of the stator segments  10  is the same as the number of the rotor support segments  20 , and an arc degree of the stator segments  10  and an arc degree of rotor support segments  20  are the same. Since the magnetic pole modules  3  are not included in the rotor support segments  20 , the assembling process of the pre-assembled modules  100  will not be affected by the magnetic pulling force between the magnetic pole modules  3  and the stator segments  10 . A dimension of a maximum chord length of each of the pre-assembled modules  100  is smaller than the road transportation limiting value, so that it is convenient for transportation from the processing site to the assembling site by means of transportation tools. 
     Referring to  FIG. 4  and  FIG. 5  together, in the splicing step S 2 , the splicing the two or more stator segments  10  and the two or more rotor support segments  20  in the predetermined manner to form the stator  1  and the rotor support  2  that are coaxially assembled respectively includes 
     step S 21 ′: coaxially assembling the stator segments  10  and the rotor support segments  20  into the pre-assembled modules  100  by the fixing members  7 , in which a predetermined gap is maintained between the stator segments  10  and the rotor support segments  20  in the pre-assembled modules  100  in the radial direction; 
     as shown in  FIG. 4  and  FIG. 5 , the large-diameter electric motor has the structure with the inner stator and the outer rotor, each of the number of the stator segments  10  and the number of the rotor support segments  20  is 3, the rotor support segments  20  and the stator segments  10  are assembled in pairs to form the pre-assembled modules  100 , and at least two fixing members  7  pass through the rotor support segments  20  and the stator segments  10  in the radial direction, respectively, so that the fixing members  7  can not only maintain the predetermined gap between the rotor support segments  20  and the stator segments  10  in the radial direction, but also ensure the safety of transportation; 
     step S 22 ′: assembling two or more pre-assembled modules  100  in the circumferential direction into the stator  1  and the rotor support  2  that are coaxially assembled; and 
     step S 23 ′: removing the fixing members  7  in the pre-assembled module  100 . 
     The pre-assembled module  100  can preset the predetermined gap in the radial direction between the rotor support segments  20  and the stator segments  10  at the processing site; after two or more pre-assembled modules  100  are assembled in the circumferential direction and then the fixing members  7  are removed, and the predetermined gap can be maintained to be unchanged, thereby ensuring that the air gap between the magnetic pole modules  3  and the stator  1  can be maintained to be unchanged. 
     Further referring to  FIG. 3 , in the step S 22 ′, the assembling two or more pre-assembled modules  100  in the circumferential direction includes 
     step S 221 ′: providing the main shaft  4 , in which the main shaft  4  includes the fixing shaft  41  and the rotating shaft  42  that are arranged coaxially, and the bearing  43  arranged between the fixing shaft  41  and the rotating shaft  42 ; 
     step S 222 ′: fixing the stator segments  10  of two or more pre-assembled modules  100  to the fixing shaft  41  in the circumferential direction; 
     in which the first outer flange plate  411  is arranged at the outer circumference of the fixing shaft  41 , and two or more stator segments  10  are fixed to the first outer flange plate  411  in the circumferential direction to form the complete stator  1 ; and 
     step S 223 ′: fixing the rotor support segments  20  of two or more pre-assembled modules  100  to the rotating shaft  42  in the circumferential direction, so that the rotor support  2  sleeves on the outer peripheral side of the stator  1 , or the stator  1  sleeves on the outer peripheral side of the rotor support  2 . 
     in which taking the rotating shaft  42  sleeving on the outer peripheral side of the fixing shaft  41  as an example, the second outer flange plate  421  is arranged at the outer circumference of the rotating shaft  42 , and two or more rotor support segments  20  are fixed to the second outer flange plate  421  in the circumferential direction to form the complete rotor support  2 . 
     In addition, since there may be the gap between two adjacent rotor support segments  20  or between two adjacent stator segments  10  in the circumferential direction due to assembly errors, the elastic sealing member, such as the O-shaped ring sealing member or the like, can be placed in the gap. 
     Referring to  FIG. 6  to  FIG. 8 ,  FIGS. 6-8  show structural schematic views of the magnetic pole modules  3  and effect views of the magnetic pole modules  3  assembling to the mounting surface  2   a  of the rotor support  2 . 
     The magnetic pole modules  3  serve as an excitation source of the electric motor, and a direct current coil excitation or a permanent magnetic excitation is commonly used. Take the permanent magnetic excitation as an example, each of the magnetic pole modules  3  generally includes a base plate  31  and a plurality of magnetic steels  32  sequentially arranged on the base plate  31  in a length direction of the base plate  31 ; the plurality of magnetic steels  32  are bonded to the base plate  31  by a structural glue, or connected to the base plate  31  by means of a screwing or the like. In order to prevent the plurality of magnetic steels  32  from moving in the length direction of the base plate  31 , flow-guiding strips  33  are also respectively arranged at two ends of the base plate  31  in the length direction of its own. The magnetic pole modules  3  can be pre-manufactured at the processing site. 
     The base plate  31  can be made of a magnetic conductive material, such as low carbon steel, silicon steel or the like; the magnetic steel  32  is made of a hard magnetic material, such as a ferrite permanent magnetic materials or the like; and the flow-guiding strip  33  is made of a weak magnetic conductive material, such as stainless steel, fiber reinforced polymer/plastic (FRP) or the like. The flow-guiding strip  33  is fixed on the base plate  31  by a non-magnetic fastening member. On the one hand, the base plate  31  provides support for the plurality of magnetic steels  32 , on the other hand, provides a magnetic path for adjacent magnetic pole modules  3 . 
     A surface of each of the magnetic pole modules  3  is generally wrapped with a glass fiber cloth first, and then is embeddingly encapsulated, so that the magnetic pole modules  3  can be isolated from the outside air and the risk of failure can be reduced. Connecting portions  311  are arranged at two sides of the base plate  31  in the circumferential direction of the rotor support  2 , and the entire magnetic pole modules  3  can move along mounting rails formed between two adjacent pressing strips  5  through the connecting portions  311 . 
     As described above, the electric motor can be the structure with the inner stator and the outer rotor, that is, the rotor is arranged along the outer circumference of the stator  1 , and the mounting surface  2   a  of the rotor support  2  is an inner circumference face of the rotor support  2 ; the electric motor can also be the structure with the inner rotor and the outer stator, that is, the stator  1  is arranged along the outer circumference of the rotor, and the mounting surface  2   a  of the rotor support  2  is an outer peripheral face of the rotor support  2 , so that the magnetic pole modules  3  are arranged opposite to the stator  1 . 
     As shown in  FIG. 8 , taking the electric motor having the structure with the inner stator and the outer rotor as an example, the pressing strips  5  made of the weak magnetic conductive material is connected to the inner circumferential face of the rotor support  2 , that is, the mounting surface  2   a , through a stainless steel fastening member. 
     Therefore, in the assembling step S 3 , assembling the plurality of magnetic pole modules  3  to the mounting surface  2   a  of the rotor support  2  through the predetermined gap includes 
     step S 31 : pre-arranging a plurality of pressing strips  5  on the mounting surface  2   a  of the rotor support  2 , so that each of the mounting rails is formed between each two adjacent pressing strips  5 ; 
     step S 32 : placing the plurality of magnetic pole modules  3  on the mounting rails respectively, in which each of the magnetic pole modules  3  includes the base plate  31  and a plurality of magnetic steels  32  arranged on the base plate  31 , the connecting portions  311  are arranged at two sides of the base plate  31  in the circumferential direction of the rotor support  2 , and the base plate  31  is placed and attached on the mounting surface  2   a ; and 
     step S 33 : pressing the pressing strips  5  on the adjacent magnetic pole modules  3  and fixing the pressing strips  5  on the mounting surface  2   a , in which, for example, the pressing strips  5  can be pressed onto the connecting portions  311  of the adjacent magnetic pole modules  3 . 
     Further, in order to avoid an abnormal deformation of the rotor caused by the non-uniform magnetic pulling force, in the step S 32 , the placing the plurality of magnetic pole modules  3  on the mounting rails respectively includes 
     placing the plurality of the magnetic pole modules  3  on first mounting rails and second mounting rails in sequence, respectively, in which the mounting rails includes a plurality of first mounting rails distributed at 180° in the circumferential direction of the rotor support and a plurality of second mounting rails distributed at the other 180° in the circumferential direction of the rotor support  2 . 
     As a result, the magnetic pulling force between the magnetic pole modules  3  of the rotor and the stator  1  always keeps balance in the radial direction, so that it can further improve the convenience of assembling the large-diameter electric motor. 
     Further, the method for assembling the large-diameter electric motor provided by the embodiments of the present disclosure further includes 
     step S 34 : providing the fastening member  6 , adjusting a radial distance between the pressing strips  5  and the mounting surface  2   a  by the fastening member  6 , and fixing the pressing strips  5  to the mounting surface  2   a  by the fastening member  6 . 
     Before the magnetic pole modules  3  are inserted into the mounting rails, it can be ensured that there is the gap between the pressing strips  5  and the mounting surface  2   a  by mean of loosening the fastening member  6 , so as to facilitate inserting the magnetic pole modules  3 . 
     Those skilled in the art should understand that the above-mentioned embodiments are all illustrative and not limited. Different technical features appearing in different embodiments can be combined to achieve beneficial effects. Those skilled in the art should be able to understand and implement other modified embodiments of the disclosed embodiments on the basis of studying the drawings, description, and claims. In the claims, the term “comprising” does not exclude other means or steps; when an article is not modified with a quantitative word, it is intended to include one/kind or multiple/kind of articles, and can be used interchangeably with “one/kind or multiple/kind of articles; the terms “first” and “second” are used to denote names rather than to indicate any specific order. Any reference signs in the claims should not be understood as limiting the scope of protection. The functions of multiple parts appearing in the claims can be implemented by a single hardware or software module. The appearance of certain technical features in different dependent claims does not mean that these technical features cannot be combined to achieve beneficial effects.