CN-121986435-A - Rotary electric machine and method for manufacturing stator in rotary electric machine

CN121986435ACN 121986435 ACN121986435 ACN 121986435ACN-121986435-A

Abstract

The invention constructs stator coil of rotary electric machine by concentric winding mode. The stator coil is constituted by inserting and connecting coil pieces 10, 11, 20, 21, 30, 31 formed of flat wires in a hairpin shape from one side and the other side in the axial direction. The length of the linear portion of the coil piece is half the axial length of the stator core, and the protruding portion and the recessed portion are fitted by forming a protruding portion or a recessed portion at both leg end portions. The coil assembly is composed of 3 kinds of coil pieces, namely, central coil pieces 10 and 11 which are connected between the slots in the circumferential direction near the radial center of the slots, inner coil pieces 20 and 21 which are connected in the circumferential direction in a manner that the coil end portions are biased to the radial inner side than the radial positions of the slots, and outer coil pieces 30 and 31 which are connected in the circumferential direction in a manner that the coil end portions are biased to the radial outer side. The lengths of the concentric coil portions constituted by the connected center coil pieces 10 and 11, coil pieces 20 and 31, and coil pieces 30 and 21 are made the same so that the resistance values become uniform, and the assemblability is improved.

Inventors

ENOMOTO YUJI
TOKOI HIROOKI
ASAUMI YUSUKE
TAKEUCHI KEISUKE
OHKI Takanori
Mu Cunshou
SAKAI TORU
AMAIKE Masaru

Assignees

株式会社日立产机系统

Dates

Publication Date: 20260505
Application Date: 20240611
Priority Date: 20231114

Claims (15)

1. A rotating electrical machine, characterized by comprising: A rotor fixed to the rotating shaft, and A stator in which a plurality of U-shaped coil pieces formed of flat wires are inserted into a plurality of slots for accommodating the flat wires from one side or the other side in the rotation axis direction of a stator core formed in the circumferential direction and connected to each other to form coils, The coil piece is formed by a flat wire and comprises 2 straight line parts which are parts accommodated in the grooves at intervals in the circumferential direction, and coil end parts which are formed in a manner of extending from the straight line parts to the outer side of the rotating shaft direction and connect the 2 straight line parts, A center coil piece, an inner coil piece, and an outer coil piece are prepared as the coil pieces, wherein, The linear portion and the coil end portion of the center coil piece are arranged on a circumference when viewed from the rotation axis direction, The coil end portion of the inner coil piece is bent radially inward with respect to a receiving portion received in the groove, The coil end of the outer coil piece is bent radially outward with respect to a receiving portion received in the groove, The coil end portions of the inner coil pieces are formed such that the circumferential length of the coil end portions of the inner coil pieces is shorter than the circumferential length of the coil end portions of the center coil pieces and the circumferential length of the coil end portions of the outer coil pieces is longer than the circumferential length of the coil end portions of the center coil pieces, A pair of the central coil pieces inserted into the first slot group from one side or the other side of the rotation axis direction and electrically connected to each other, an The inner coil piece and the outer coil piece are inserted into the second slot group or the third slot group from one side or the other side in the rotation axis direction and electrically connected, thereby forming a concentrically wound stator coil.
2. A rotary electric machine as recited in claim 1, wherein: The coil end is formed of 2 extending portions extending from the straight portion of the coil piece to the outer side in the rotation axis direction, and a connecting portion connecting the end portions of the extending portions in the circumferential direction, After the connection wire forms the stator coil, the connection portions of the center coil pieces are arranged in a radially aligned manner, By providing the inner coil piece with an angle such that the extension portion of the inner coil piece is bent radially inward, the connection portion of the inner coil piece is arranged so as to be laminated in the rotation axis direction at a portion radially inward of the lamination portion of the center coil piece, By providing the angle such that the extension portion of the outer coil piece is bent radially outward, the connection portion of the outer coil piece is arranged so as to be laminated in the rotation axis direction at a portion radially outward of the lamination portion of the connection portion of the center coil piece.
3. A rotary electric machine as recited in claim 2, wherein: The angle of the bending portion of the extending portion of the inner coil piece to the inside with respect to the straight portion is an angle of more than 0 degrees and 45 degrees or less, The angle of the bending portion of the extending portion of the outer coil piece to the outside with respect to the straight portion is greater than 0 degree and less than 45 degrees, The coil length of one turn formed by alternately connecting the inner coil pieces and the outer coil pieces coincides with the coil length of one turn formed by 2 of the center coil pieces.
4. A rotary electric machine as claimed in claim 3, characterized in that: when the coil pieces are inserted into the slots of the stator core from both sides in the rotation axis direction, the center coil piece, the inner coil piece, and the outer coil piece may be inserted and assembled one by one in order parallel to the rotation axis direction.
5. A rotary electric machine as recited in claim 1, wherein: By forming the stator coils by concentric winding, it is possible to construct a greater number of parallel connections than the number of slots per phase per pole.
6. A rotary electric machine as claimed in claim 3, characterized in that: The stator core is composed of a back core body and a plurality of tooth cores combined with the back core body, The tooth core uses a low-loss soft magnetic material, and Resin bobbins for accommodating a plurality of flat wires in the radial direction are disposed in the grooves between the adjacent tooth cores.
7. A rotary electric machine as claimed in claim 3, characterized in that: The winding is configured to simultaneously cope with a plurality of voltage specifications and a plurality of control devices by one winding specification.
8. A rotary electric machine as claimed in claim 3, characterized in that: an odd number of turns is formed in 1 of the slots.
9. A control system for a rotating electrical machine, characterized by: the rotating electrical machine is the rotating electrical machine according to claim 3, The stator coil adopts a parallel triangle winding structure, A plurality of inverter devices are connected to each of the triangular winding portions, The inverter device is configured to be capable of independently supplying an excitation voltage to the delta winding portion.
10. A control system of a rotary electric machine according to claim 9, characterized in that: converter circuits corresponding to the inverter devices are provided, and power is supplied to the converter circuits from an independent system power supply.
11. A method of manufacturing a stator in a rotating electrical machine, characterized by: The rotating electrical machine includes a rotor fixed to a rotating shaft, a stator disposed on an outer peripheral side of the rotor, the stator having a stator core in which a plurality of slots are formed in a circumferential direction, and a stator coil formed of a plurality of U-shaped coil pieces formed of flat wires inserted into the slots from a lead-out side or a lead-out opposite side in a direction of the rotating shaft, In the rotating electrical machine, a spool having slots for receiving m flat wires in a radial direction is disposed in each of the slots, The following steps a to d are performed for the coil pieces inserted from the lead-out side in the rotation axis direction: A step a of preparing m-1 center coil pieces, m-1 outer coil pieces, and m-1 inner coil pieces as a group of the coil pieces formed of 2 straight portions and coil end portions, wherein the 2 straight portions are accommodated in the slots separated by 5 slots in the circumferential direction, the coil end portions are formed so as to extend outward in the rotational axis direction from the straight portions, the 2 straight portions are connected to each other so as to extend in the rotational axis direction and the circumferential direction, the outer coil pieces are bent so as to bend the coil end portions radially outward, the inner coil pieces are bent so as to bend the coil end portions radially inward, Step b of inserting m-1 kinds of inner side coil pieces circumferentially over the entire circumference thereof from the slot serving as a starting point of the inner side coil pieces so that connection portions extending in the circumferential direction of coil ends of the m-1 kinds of inner side coil pieces are stacked in the radial direction, Step c of inserting m-1 types of the outer coil pieces circumferentially over the entire circumference from the slot holes at positions separated by 4 slots circumferentially from the start point of the inner coil piece so that connection portions of the coil ends of the m-1 types of the outer coil pieces extending circumferentially are stacked in the rotation axis direction, Step d of inserting m-1 kinds of the center coil pieces circumferentially over the entire circumference thereof from a position circumferentially apart from the start point by 2 slots so that connection portions extending in the circumferential direction of coil ends of the m-1 kinds of the center coil pieces are arranged in the radial direction, The coil pieces inserted from the opposite side of the rotation axis direction are subjected to the following steps e to h: A step e of preparing m center coil pieces, m outer coil pieces, and m inner coil pieces as a group of the coil pieces formed of 2 straight portions and coil end portions, wherein the 2 straight portions are accommodated in the slots separated by 5 slots in the circumferential direction, the coil end portions are formed so as to extend outward in the rotation axis direction from the straight portions, the 2 straight portions are connected to each other by extending in the rotation axis direction and the circumferential direction, the outer coil pieces are bent so as to bend the coil end portions radially outward, the inner coil pieces are bent so as to bend the coil end portions radially inward, Step f of inserting m-1 kinds of inner side coil pieces circumferentially over the entire circumference thereof from the slot hole serving as the starting point of the inner side coil pieces so that connection portions extending in the circumferential direction of coil ends of the m-1 kinds of inner side coil pieces are stacked in the radial direction, Step g of inserting m-1 types of the outer coil pieces circumferentially over the entire circumference from the slot holes at positions separated by 4 slots circumferentially from the start point of the inner coil piece so that connection portions of the coil ends of the m-1 types of the outer coil pieces extending circumferentially are stacked in the rotation axis direction, Step h of inserting m-1 kinds of the center coil pieces circumferentially over the entire circumference thereof from a position circumferentially apart from the start point by 2 slots so that connection portions extending in the circumferential direction of coil ends of the m-1 kinds of the center coil pieces are arranged in the radial direction, A concentric winding coil is formed by connecting, in the slot hole, the group of coil pieces inserted into the slot of the stator core from the lead-out side and the group of coil pieces inserted from the opposite lead-out side.
12. The method of manufacturing a stator in a rotating electrical machine according to claim 11, wherein: a plurality of lead wires are prepared by bending a straight flat wire into a crank-like shape, On the lead-out side in the direction of the rotation axis, Before the step b is executed, 1 lead tab is arranged in the innermost Zhou Caokong at the starting point side of the inner coil tab and 1 lead tab is arranged in the outermost peripheral groove at the other side, Before the step c is performed, 1 lead tab is arranged in the innermost Zhou Caokong on the start side where the outer coil piece is accommodated, 1 lead tab is arranged in the outermost peripheral groove on the other side, Before the step d is performed, 1 tab is arranged in an innermost peripheral groove on one side of the groove for accommodating the central coil piece, and 1 tab is arranged in an outermost peripheral groove on the other side.
13. The method of manufacturing a stator in a rotating electrical machine according to claim 12, wherein: A convex portion or a concave portion is formed at the open ends of the inner coil piece, the center coil piece, and the lead-out piece on the lead-out side, A concave portion or a convex portion corresponding to the lead-out side is formed at the open end portions of the inner coil piece, and the center coil piece on the opposite lead-out side, The coil pieces are electrically connected by fitting the convex portions and concave portions of the coil pieces on the lead-out side and the opposite lead-out side into the slots of the bobbin.
14. The method of manufacturing a stator in a rotating electrical machine according to claim 13, wherein: the order of execution of the assembly of said step b and the assembly of said step c can be reversed, The order of execution of the assembly of step f and the assembly of step g can be reversed.
15. The method of manufacturing a stator in a rotating electrical machine according to claim 14, wherein: The coil end portions of the inner coil pieces are formed such that the circumferential length of the coil end portions of the inner coil pieces is shorter than the circumferential length of the coil end portions of the center coil pieces, and the circumferential length of the coil end portions of the outer coil pieces is longer than the circumferential length of the coil end portions of the center coil pieces, Connecting the center coil piece on the lead-out side with the center coil piece on the opposite lead-out side, Connecting the inner coil piece of the leading-out side with the outer coil piece of the opposite leading-out side, The outer coil piece on the lead-out side is connected to the inner coil piece on the opposite lead-out side, whereby the circumferential lengths of the concentric portions are made uniform.

Description

Rotary electric machine and method for manufacturing stator in rotary electric machine Technical Field The present invention relates to a rotating electrical machine having a stator structure in which coils having different coil end shapes for respective phases are wound concentrically to form a stator coil of a radial gap type rotating electrical machine, and in which resistance values can be made the same in the respective phases, a method of manufacturing a stator of the rotating electrical machine, and a control system of the rotating electrical machine. Background As a power source of industrial machinery and a rotating electric machine (motor) for driving an automobile, improvement in efficiency is demanded. In order to improve the efficiency of a rotating electrical machine, it is necessary to reduce the loss of the rotating electrical machine, and a design method for researching a design for reducing two major loss factors of the rotating electrical machine, namely, coil copper loss and core iron loss, is generally adopted. When the output characteristics (rotation speed and torque) of the rotating electrical machine, which are required specifications, are determined, the mechanical loss is determined uniquely, so that a design to reduce the iron loss and copper loss is important. The core loss can be reduced by using a soft magnetic material. In a general rotating electrical machine, an electromagnetic steel sheet is used in a core portion, and the level of loss varies depending on the thickness, si content, and the like. The soft magnetic material includes high performance materials such as iron-based amorphous metals, FINEMET (iron-based nanocrystalline magnetically soft alloy), and nanocrystalline materials that can be expected to have a high magnetic flux density, which have a higher magnetic permeability and a lower iron loss than those of electromagnetic steel plates, but these materials have a thickness of 0.025mm and are very thin, and have a hardness of 900 vickers hardness, 5 times or more that of electromagnetic steel plates, and the like, and these high performance materials have not been able to be applied to rotating electrical machines because of many technical problems in terms of inexpensive manufacturing of rotating electrical machines. Copper loss is mainly determined by the relationship between the resistance value of the coil and the current, and therefore countermeasures such as reducing the resistance value of the coil by cooling and reducing the current value by suppressing the decrease in the residual magnetic flux density of the magnet are taken. In recent years, motors for driving automobiles and the like have been designed such that the ratio (area ratio) of the cross-sectional area of a conductor to the stator slot is increased to reduce the resistance value to a theoretical limit. However, in the coil using a flat wire which can increase the space factor in the slot, the lead-in (wiring) structure of the coil end portion extending from both ends of the slot to the outside is complicated, and there are problems such as an increase in the volume (wire length) of the coil end portion and a slight increase in the resistance value by connecting these conductors by soldering or the like. Patent document 1 discloses a technique in which hairpin conductor segments are inserted into a stator coil of an electric motor, and the coil ends on the side opposite to the inserted end are bent and formed, respectively, and welded to a bent conductor of another hairpin coil arranged in the circumferential direction to form a circular coil. This method has an effect of improving the slot occupancy rate, but since it is necessary to bend and shape a thick and hard flat conductor during manufacturing, there are cases where stress applied to the stator core, damage to slot insulation, or residual stress when bending remains in the connection portion, and it is difficult to ensure the welding joint reliability, and there is room for improvement in the manufacturing method. In addition, since a space around the welded portion must be ensured in order to perform welding, there is a problem in that the coil end portion becomes large on the welding side. Among methods for attempting to improve these problems, the technique of patent document 2 is known. Patent document 2 discloses a method of mechanically firmly joining a coil with its tip shape as a press-fit tolerance. In addition, in patent document 2, since the resin bobbin is used, and the tip ends of the irregularities are bonded by applying stress in a state where the insertion region of the coil is reliably secured, highly reliable connection can be achieved. In the stator structure using flat wires shown in patent documents 1 and 2, a winding structure called wave winding is adopted. The reason for this is that the coil shape is the same in the circumferential direction, so that the coil having a hairpin shape can be easily formed, twist