Patent Publication Number: US-2022239176-A1

Title: Stator, terminal block, and rotating electric machine

Description:
TECHNICAL FIELD 
     The present invention relates to a stator of a rotating electric machine. 
     BACKGROUND ART 
     In the present invention, a rotating electric machine is required to have a high output, and it is desired to increase a turn of a coil. 
     Background art of the present technical field includes the following prior art. In Patent Literature 1 (WO 2017/195481A), the axial length of the stator is extended to increase the size, and the connection points are on both end sides of the stator core, so that the productivity of the rotating electric machine is deteriorated. A rotating electric machine includes: a stator core; a stator winding including a plurality of segment coils; and a wire connection plate that fixes a different-phase connection conductor connecting different phases of segment coils of the stator winding and an in-phase connection conductor connecting in-phase segment coils of the stator winding. The stator winding includes a coil connection portion to which ends of the plurality of segment coils are connected on one side with respect to an axial direction of the stator core, and the wire connection plate is disposed on a side where the coil connection portion is disposed with respect to the stator core. 
     CITATION LIST 
     Patent Literature 
     PTL 1: WO 2017/195481 A 
     SUMMARY OF INVENTION 
     Technical Problem 
     With such an increase in the number of turns of a stator coil, there is a problem that the temperature rises in the input/output portion where the coils are densely arranged. Therefore, cooling of the coil by a coolant (for example, ATF) flowing into the slot is required. However, the wire connection plate attached to the upper surface side of the stator may prevent the coolant from flowing into the slot. For this reason, the shape of the wire connection plate that does not prevent the inflow of the coolant is required. 
     Solution to Problem 
     A representative example of the invention disclosed in the application is as follows. That is, a stator of a rotating electric machine includes: a stator core; a plurality of segment coils protruding from slots of the stator core and arranged in a radial direction; a connection conductor that connects the segment coils; and an insulating member that holds the connection conductor. The insulating member includes a through hole through which the segment coil penetrates and is accommodated. An opening through which a coolant can flow into the through hole is provided on an inner peripheral side of the insulating member. 
     Advantageous Effects of Invention 
     According to the present invention, the rotor coil can be efficiently cooled even by the rotor provided with the wire connection plate. Objects, configurations, and effects besides the above description will be apparent through the explanation on the following embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram illustrating an overall configuration of a rotating electric machine according to an embodiment of the present invention. 
         FIG. 2  is a perspective view illustrating a stator attached to a housing of the present embodiment. 
         FIG. 3  is a perspective view of a stator removed from the housing of the present embodiment. 
         FIG. 4  is a perspective view of a wire connection plate of the present embodiment. 
         FIG. 5  is a perspective view of an input/output connection conductor built in the wire connection plate of the present embodiment. 
         FIG. 6  is a sectional view of the stator in a state where the wire connection plate of the present embodiment is attached. 
         FIG. 7  is a plan view of the stator to which the wire connection plate of the present embodiment is attached. 
         FIG. 8  is a plan perspective view of the stator to which the wire connection plate of the present embodiment is attached. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described with reference to the drawings. 
     The rotating electric machine according to the present embodiment is a rotating electric machine suitable for use in traveling of an automobile. Here, a so-called electric vehicle using a rotating electric machine includes a hybrid type electric vehicle (HEV) including both an engine and a rotating electric machine and a pure electric vehicle (EV) that travels only with a rotating electric machine without using an engine, but the rotating electric machine described below can be used for both types. 
       FIG. 1  is a schematic diagram illustrating an overall configuration of a rotating electric machine  100  according to an embodiment of the present invention.  FIG. 1  illustrates the inside of the rotating electric machine  100  with a part of the rotating electric machine  100  as a cross section. The rotating electric machine  100  is disposed inside a case  10  and includes a housing  112 , a stator  130  having a stator core  132  fixed to the housing  112 , and a rotor  150  rotatably disposed in the stator  130 . The case  10  may be configured by a case of an engine or a case of a transmission. 
     The rotating electric machine  100  is a three-phase synchronous motor with a built-in permanent magnet. In the present embodiment, a three-phase synchronous motor will be described as an example of the rotating electric machine  100 , but the present invention can also be applied to an induction motor. 
     The rotating electric machine  100  of the present embodiment operates as an electric motor that rotates the rotor  150  by supplying a three-phase alternating current to a stator coil  138  wound around the stator core  132 . When driven by an engine, the rotating electric machine  100  operates as a generator and outputs generated power of three-phase alternating current. That is, the rotating electric machine  100  has both a function as an electric motor that generates rotational torque on the basis of electric energy and a function as a generator that generates power on the basis of mechanical energy, and the above-described functions can be selectively used depending on the traveling state of the automobile. 
     The stator  130  is fixed to the housing  112 . The stator  130  is fixed and held in the case  10  by fastening a flange  115  provided in the housing  112  to the case  10  with a bolt  12 . The rotor  150  fixed to a rotation shaft  118  is supported by bearings  14 A and  14 B of the case  10 , and is rotatably held inside the stator core  132 . 
       FIG. 2  is a perspective view illustrating the stator  130  attached to the housing  112 , and  FIG. 3  is a perspective view of the stator  130  detached from the housing  112 . In  FIG. 3 , a part of the stator core  132  is omitted. 
     The housing  112  is formed in a cylindrical shape by drawing a steel plate (such as a high-tensile steel plate) having a thickness of about 2 to 5 mm. The flange  115  is provided at one axial end of the housing  112 , and is fixed to the case  10  with the bolt  12  as described above (see  FIG. 1 ). The flange  115  is formed integrally with the housing  112  by drawing. Note that the stator  130  may be directly fixed to the case  10  without providing the housing  112 . 
     The stator  130  is fixed to the inner peripheral side of the housing  112  and includes the cylindrical stator core  132 , and the stator coil  138  and a wire connection plate  140  attached to the stator core  132 . The stator core  132  is formed by stacking a plurality of electromagnetic steel sheets  133  formed by punching or etching with a thickness of about 0.05 to 1.0 mm, for example. The laminated electromagnetic steel sheets  133  are connected and fixed by welding, and deformation of the electromagnetic steel sheets  133  due to a fastening force when being press-fitted into the housing  112  is suppressed. 
     In the stator core  132 , a plurality of slots  122  extending in the axial direction is formed at equal intervals in the circumferential direction. The number of slots  122  is, for example, 72 in the present embodiment. As illustrated in  FIG. 2 , the stator coil  138  is accommodated in the slot  122 . In the example illustrated in  FIG. 3 , the slot  122  is an open slot, and an opening is formed on the inner peripheral side of the stator core  132 . The circumferential width of the opening may be substantially equal to or slightly smaller than the coil mounting portion of each slot  122  to which the stator coil  138  is mounted. 
     A slot liner  300  is disposed in each slot  122 . The slot liner  300  is formed of, for example, a heat-resistant resin into a predetermined shape, and has a thickness of about 0.1 to 0.5 mm. The slot liner  300  is disposed in the slot  122  or in the coil end. The slot liner  300  is disposed between the coils inserted into the slot  122  and between the coil and the inner surface of the slot  122 , and functions as an insulating member to improve the withstand voltage between the coils and between the coil and the inner surface of the slot  122 . 
     The stator coil  138  is formed by connecting a plurality of U-shaped segment coils to each other. The segment coil is disposed such that one end thereof is adjacent to the other segment coil and the other end thereof is further adjacent to the other segment coil such that the end thereof is exposed from the slot  122  (that is, the stator  130 ). The segment coils whose ends are adjacent to each other are connected to each other at the adjacent ends to form the stator coil  138  wound around the stator core  132 . 
     The wire connection plate  140  for connecting the stator  130  and the electric circuit is attached to a part of the end of the segment coil of the stator coil  138 . 
     In addition, the slot liner  300  disposed at the coil end is annularly disposed between the coils for inter-phase insulation and inter-conductor insulation at the coil end. As described above, in the rotating electric machine  100  of the present embodiment, since the slot liner  300  is disposed inside the slot  122  or at the coil end, it is possible to maintain a required withstand voltage even if the insulation film of the coil is damaged or deteriorated. 
     Teeth  121  are formed between the slots  122 , and each tooth  121  is integrally molded with the annular core back  123 . The stator core  132  is an integrated core in which the teeth  121  and the core back  123  are integrally molded. The teeth  121  guide the rotating magnetic field generated by the stator coil  138  to the rotor  150 , and cause the rotor  150  to generate rotational torque. 
     The rotor  150  includes a rotor core  152  and a permanent magnet  154  held in a magnet insertion hole formed in the rotor core  152 . 
     In the rotor core  152 , rectangular parallelepiped magnet insertion holes are formed at equal intervals in the circumferential direction in the vicinity of the outer peripheral portion. The permanent magnet  154  is embedded in each magnet insertion hole and fixed with an adhesive or the like. A circumferential width of the magnet insertion hole is formed to be larger than a circumferential width of the permanent magnet  154 , and magnetic gaps  156  are formed on both sides of the permanent magnet  154 . The magnetic gap  156  may be filled with an adhesive or may be fixed integrally with the permanent magnet  154  with a resin. 
     The permanent magnet  154  forms a field pole of the rotor  150 . In the present embodiment, one magnetic pole is formed by one permanent magnet  154 , but one magnetic pole may be formed by a plurality of permanent magnets  154 . By increasing the number of permanent magnets  154  for forming each magnetic pole, the magnetic flux density of each magnetic pole generated by the permanent magnet  154  increases, and the magnet torque can be increased. As the permanent magnet  154 , a neodymium-based or samarium-based sintered magnet, a ferrite magnet, a neodymium-based bonded magnet, or the like can be used, but the residual magnetic flux density of the permanent magnet  154  is desirably about 0.4 to 1.3 T, and a neodymium-based magnet is more suitable. An auxiliary magnetic pole may be formed between the permanent magnets  154 . 
     When the three-phase alternating current is supplied to the stator coil  138  to generate a rotating magnetic field in the stator  130 , the rotating magnetic field acts on the permanent magnet  154  of the rotor  150  to generate a magnet torque. Since the reluctance torque described above is generated in the rotor  150  in addition to the magnet torque, both the magnet torque and the reluctance torque described above act as the rotational torque in the rotor  150 , and a large rotational torque can be obtained. 
     The wire connection plate  140  will be described with reference to  FIGS. 4, 5, 6, and 7 .  FIG. 4  is a perspective view of the wire connection plate  140 ,  FIG. 5  is a perspective view of an input/output connection conductors  144  arranged inside the wire connection plate  140 ,  FIG. 6  is a sectional view of the stator  130  in a state in which the wire connection plate  140  is attached, and  FIG. 7  is a plan view of the stator  130  to which the wire connection plate  140  is attached. 
     The wire connection plate  140  includes the input/output connection conductor  144  (see  FIG. 5 ) as a lead wire that connects the outside of the rotating electric machine  100  and the stator  130 , connection conductors  145  and  146  as relay wires that connect the segment coils, and an insulating member  141  that holds the input/output connection conductor  144  and the connection conductors  145  and  146 . A connection terminal  142  is connected to the end of the input/output connection conductor  144  (see  FIGS. 2 and 3 ). 
     The insulating member  141  is configured to hold the input/output connection conductor  144  and the connection conductors  145  and  146  by integral molding of a resin material. The insulating member  141  is opened (opening  1412 ) on the inner peripheral side, and forms a comb-like resin terminal block. This opening  1412  is used to introduce cooling oil into the slots  122  of the stator core  132 , as will be described later. 
     As illustrated in  FIG. 5 , the connection conductors  145  and  146  include an in-phase connection conductor  145  that connects in-phase segment coils and a different-phase connection conductor  146  that connects different-phase segment coils. The connection conductors  144 ,  145 , and  146  are fixed in the insulating member  141  at constant intervals for electrical insulation in the wire connection plate  140 . 
     As illustrated in  FIGS. 3, 4, and 7 , by passing the end of the segment coil in the axial direction into the through hole  1411  of the wire connection plate  140 , the wire connection plate  140  is mounted at a position between the axial end of the segment coil and the axial end of the stator core. By mounting the wire connection plate  140  at this position, the length of the coil end of the stator coil  138  can be shortened, and the rotating electric machine  100  can be downsized. 
     The insulating member  141  has a size such that an inner peripheral side surface thereof is positioned on an outer peripheral side of the tip of the teeth  121  at a position attached to the stator  130 . Therefore, when the rotor  150  is inserted into the stator  130 , the wire connection plate  140  and the rotor  150  can be prevented from interfering with each other, and the rotor  150  can be inserted from either the upper side or the lower side. 
     In addition, the segment coil and the connection conductors  144 ,  145 , and  146  are connected at the upper portion of the stator  130 , that is, the upper portion of the wire connection plate  140  on the axial direction side. By connecting the segment coils and the connection conductors  144 ,  145 , and  146  at the upper portion in the axial direction, the conductors can be easily clamped at the time of connecting the segment coils and the connection conductors, the connection portion can be located close to the stator core  132 , and the rotating electric machine  100  can be downsized. 
     By mounting the wire connection plate  140  on the stator coil  138  in this manner, the end of the segment coil and the ends of the connection conductors  144 ,  145 , and  146  are adjacent to each other, and the end of the segment coil and the ends of the connection conductors  144 ,  145 , and  146  can be connected. 
     Specifically, the in-phase connection conductor  145  is disposed between the two through holes  1411  adjacent to each other in the circumferential direction, and connects the innermost (first layer) segment coil and the outermost (sixth layer) segment coil in the slot  122  on the upper surface of the wire connection plate  140  (see  FIG. 5 ). 
     In addition, the end of the segment coil of the second layer and the end of the segment coil of the third layer in the slot  122  are connected, and the end of the segment coil of the fourth layer and the end of the segment coil of the fifth layer are connected. 
     Two input/output connection conductors  144  are provided in each phase, one input/output connection conductor  144  is connected to the segment coil of the innermost circumference (first layer), and the other input/output connection conductor  144  is connected to the segment coil of the outermost circumference (sixth layer). As a result, the coils of the two systems are connected to the connection terminal  142  of each phase. 
     The different-phase connection conductor  146  connects the ends of the segment coils of different phases, and may extend a neutral point forming a neutral point inside the insulating member  141  to the upper surface of the insulating member  141 . 
     In this manner, an electric circuit of the stator coil  138  is formed by the connection between the segment coil and the connection conductors  144 ,  145 , and  146 . 
     As a method of connecting the end portion of the segment coil and the end portion of each of the connection conductors  144 ,  145 , and  146  and a method of connecting the ends of the U-shaped segment coils to each other, for example, TIG welding can be used, but other joining methods such as laser welding, electron beam welding, and ultrasonic welding can also be adopted. 
     In the present embodiment, the connection conductors  144 ,  145 , and  146  adjacent to the innermost peripheral segment coil are provided at positions adjacent to the end portion of the segment coil in the circumferential direction, and the end of the conductor does not prevent the cooling oil from flowing into the opening  1412 . In addition, the connection conductors  144 ,  145 , and  146  adjacent to the outermost peripheral segment coil are provided at positions radially adjacent to the end portion of the segment coil, and are cooled by the cooling oil reaching a reservoir  1413  to be described later. 
     Next, cooling of the coil in the present embodiment will be described with reference to  FIGS. 7 and 8 .  FIG. 7  is a plan view of the stator  130  to which the wire connection plate  140  is attached, and  FIG. 8  is a plan perspective view of the stator  130  to which the wire connection plate  140  is attached. In  FIGS. 7 and 8 , the flow of the cooling oil is indicated by an arrow. 
     Cooling oil flows inside the case  10  of the rotating electric machine  100  of the present embodiment, and cools heat generated by copper loss of the stator coil  138 . For example, when the automatic transmission and the rotating electric machine  100  are housed in one case, automatic transmission fluid (ATF) flows inside the rotating electric machine  100 , and the stator coil  138  is cooled by the ATF flowing around the stator coil  138  inside the rotating electric machine  100 . In general, the ATF flows in the slot  122  from the upper surface (for example, the surface of the stator coil  138  on the welding side) of the stator  130  and flows out from the lower surface (for example, the surface on the insertion side of the segment coil) of the stator  130 . 
     In the rotating electric machine  100  of the present embodiment, since the wire connection plate  140  is attached to the upper surface side of the stator  130 , the inflow of the ATF into the stator  130  may be hindered depending on the shape of the wire connection plate  140 . Therefore, in the wire connection plate  140  of the present embodiment, the opening  1412  is provided on the inner peripheral side of the insulating member  141  of the wire connection plate  140 , and the cooling oil is introduced from the opening  1412  into the through hole  1411 . Therefore, the cooling oil can be introduced into the stator coil  138  located below the wire connection plate  140 , and the stator coil  138  located below the wire connection plate  140  can be cooled. 
     In addition, the wire connection plate  140  is provided with the reservoir  1413  wider than the opening  1412  on the outer peripheral side of the insulating member  141 . Therefore, the cooling oil flowing into the insulating member  141  from the opening  1412  reaches the reservoir  1413  and stays in the reservoir  1413 , so that the connection conductors  144 ,  145 , and  146  can be effectively cooled. In addition, since the cooling oil flowing into the insulating member  141  from the opening  1412  cools the insulating member  141 , the connection conductors  144 ,  145 , and  146  provided in the insulating member  141  can be cooled. 
     In the embodiment described above, the example in which the stator coil  138  is cooled by the cooling oil has been described, but the stator  130  of the present invention can be cooled by using a cooling medium (liquid or gas) that is not oil. 
     As described above, according to the embodiment of the present invention, the stator  130  of the rotating electric machine  100  includes the stator core  132 , the plurality of segment coils protruding from the slot  122  of the stator core  132  and arranged in the radial direction, the connection conductors  145  and  146  connecting between the segment coils, and the insulating member  141  holding the connection conductors  145  and  146 . The insulating member  141  has the through hole  1411  through which the segment coil penetrates and is accommodated, and has the opening  1412  through which the coolant can flow into the through hole  1411  on the inner peripheral side of the insulating member  141 . Therefore, even the stator  130  provided with the wire connection plate  140  can efficiently cool the stator coil  138 . 
     In addition, since the insulating member  141  has the reservoir  1413  where the coolant flowing from the opening  1412  reaches on the outer peripheral side of the through hole  1411 , the coolant flows into the reservoir  1413 , and the connection conductors  144 ,  145 , and  146  can be effectively cooled. 
     In addition, since the connection conductors  145  and  146  are connected adjacent to the segment coil disposed on the outermost periphery in the radial direction and are connected adjacent to the segment coil disposed on the innermost periphery in the circumferential direction, the flow of the cooling oil into the opening  1412  is not hindered, and the cooling oil reaching the reservoir  1413  can be effectively cooled. 
     Note that the above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the matters described in the above embodiment and the matters described in the claims. For example, in the above-described embodiment, a rotating electric machine including a permanent magnet in a rotor has been described as an example, but the present invention can be similarly applied to a stator of a rotating electric machine such as an induction motor. The present invention can also be applied to a rotating electric machine for driving a vehicle other than the rotating electric machine for driving a vehicle. 
     Further, the present invention is not limited to the above-described embodiments. Various modifications and equivalent configurations may be contained within the scope of claims. For example, the above-described embodiments are given in detail in order to help easy understating of the present invention. The present invention is not limited to be provided all the configurations described above. In addition, some of the configurations of a certain embodiment may be replaced with the configuration of the other embodiment. In addition, the configurations of the other embodiment may be added to the configurations of a certain embodiment. In addition, some of the configurations of each embodiment may be added, omitted, or replaced with respect to the configuration of the other embodiment. 
     REFERENCE SIGNS LIST 
     
         
           10  case 
           12  bolt 
           14 A,  14 B bearing 
           100  rotating electric machine 
           112  housing 
           115  flange 
           118  rotation shaft 
           121  teeth 
           122  slot 
           123  core back 
           130  stator 
           132  stator core 
           133  electromagnetic steel sheet 
           138  stator coil 
           140  wire connection plate 
           141  insulating member 
           1411  through hole 
           1412  opening 
           1413  reservoir 
           142  input/output connection terminal 
           144  input/output connection conductor 
           145 ,  146  connection conductor 
           150  rotor 
           152  rotor core 
           154  permanent magnet 
           156  magnetic gap 
           300  slot liner