Rail-type hairpin coil for electric motor and manufacturing method therefor

Abstract

The present invention relates to a hairpin coil used in a stator hairpin winding of a high-performance motor for vehicle and industrial applications and relates to a rail-type hairpin coil which can form a winding by adding, to a conventional rectangular hairpin, a rail shape in which two windings overlap each other.

Description

Rail-type hairpin coil for electric motor and method of manufacturing the same

[0001] The present invention relates to a hairpin coil used in the stator hairpin winding of a high-performance electric motor applied to industry and vehicles. Specifically, it relates to a hairpin coil and a method for manufacturing the same, wherein a rail shape is devised on a conventional rectangular hairpin to enable overlapping winding of two windings, and the quality of the finished product during welding is improved by utilizing the length difference between the ends of the windings during the winding bending process.

[0002] Hairpin winding, one of the coil winding methods for electric motors, is configured so that multiple copper wires are bent into a specific shape and inserted into slots.

[0003] Figure 1 illustrates a coil (10) wound using a general hairpin winding method. This hairpin winding method has high heat dissipation efficiency and efficiently utilizes slot space, allowing many coils to be wound in a limited space. Therefore, since the magnetic field density is formed uniformly, the motor's performance is improved, and noise and vibration are reduced.

[0004] This hairpin winding method is used in motors requiring high-speed rotation or high-output motors.

[0005]

[0006] FIG. 2 shows a perspective view of a single-winding hairpin coil (11) used in hairpin winding.

[0007] In the case of conventional hairpin windings, winding is performed by applying a single hairpin coil (11) to one winding area. Accordingly, for high-voltage devices requiring 8 turns, 10 turns or more, multiple hairpin coils (11) corresponding to the number of turns are required, so there is a problem of reduced economic efficiency due to the manufacturing and insertion process of multiple hairpin windings.

[0008] Meanwhile, the hairpin coil (11) includes a head portion (12) on one side in which a bend is formed, and a pair of leg portions (13) extending from the head portion (12) to the other side. The above hairpin coil (11) is electrically connected to an adjacent hairpin coil (11) through welding.

[0009]

[0010] Figure 3 shows a perspective view of the leg portion (13)(13-1) of the hairpin coils, illustrating the welded portion of a typical hairpin winding.

[0011] As described above, when defining the axial direction of the motor as the z-direction, when welding a pair of hairpin coils, the leg (13) and the leg (13-1) of the adjacent hairpin coil are butted along the x-direction (circumferential direction of the motor), and the central joint surface is welded in the y-direction (radial direction of the motor) to join them.

[0012] In the case of the above welding method, since the y-direction and z-direction alignment of the two legs (13) (13-1) is not easy, the welded product may detach and short-circuit after welding depending on the proximity of the two windings.

[0013] The present invention is a technology for developing hairpin stators for vehicle and industrial electric motors equipped with high-voltage power supplies. Electric motors equipped with high-voltage power supplies require a design with multiple stator turns (number of hairpin windings), and there are currently cases where motors with 10 or more hairpin windings have been mass-produced. Consequently, when the number of stator hairpin turns is configured in multiple ways, welding operations take a long time and the defect rate increases significantly. Accordingly, the present invention aims to provide a rail-type hairpin coil that reduces working time by applying a rail structure to the hairpin windings to configure multiple windings into a single hairpin coil, thereby performing bending operations on multiple windings simultaneously, and reducing welding labor while increasing the number of windings.

[0014] In addition, we aim to provide a rail-type hairpin coil that is easy to fix due to its rail shape when inserting multiple turns.

[0015] In addition, we aim to provide a rail-type hairpin coil that prevents multiple windings from separating due to a rail-shaped joint structure during bending and forming for hairpin manufacturing.

[0016] Meanwhile, the present invention provides a hairpin coil formed by simultaneously bending two windings of the same length while they are superimposed, thereby creating a step difference at the ends of the two windings, and bending the protruding end of the winding toward the end of the adjacent winding to perform welding through the stepped bend.

[0017] A rail-type hairpin coil according to one embodiment of the present invention is a hairpin coil wound on the stator of an electric motor, wherein the hairpin coil is formed by combining a plurality of coil units, and an insulating member made of an insulating material is provided between the plurality of coil units.

[0018] Additionally, one of the coil units includes one or more protrusions formed on the coupling surface, and another of the coil units includes one or more grooves fitted into the protrusions.

[0019] Additionally, the coil unit comprises a first coil unit and a second coil unit coupled to the first coil unit, wherein the other side in the width direction of the first coil unit and one side in the width direction of the second coil unit are joined by contact, and the first coil unit comprises a first recessed portion recessed from one side in the width direction to one side and a first protrusion protruding from one side in the width direction adjacent to the first recessed portion to the other side, and the second coil unit comprises a second protrusion protruding from one side in the width direction to one side corresponding to the first recessed portion and a second recessed portion recessed from one side in the width direction to the other side corresponding to the first protrusion.

[0020] In addition, the protrusions and grooves are formed continuously along the length direction of the hairpin coil.

[0021] In addition, the insulating member has a predetermined thickness and is provided between the joining surfaces of the plurality of coil units.

[0022] In addition, the insulating member is coated or applied to the outer surface of each of the coil units with a predetermined thickness.

[0023] Additionally, the coil unit comprises a first coil unit and a second coil unit coupled to the first coil unit, wherein the first coil unit is formed in a 'C' shape including a first groove portion recessed from one side in the width direction to the other, and the second coil unit is formed in a 'C' shape including a second groove portion recessed from the other side in the width direction to one side, wherein the other side in the thickness direction of the first coil unit is fitted into the first groove portion, and the one side in the thickness direction of the second coil unit is fitted into the second groove portion, so that the first coil unit and the second coil unit are interlocked and coupled to each other.

[0024] A rail-type hairpin coil according to another embodiment of the present invention is a hairpin coil wound on the stator of an electric motor, wherein the hairpin coil comprises: a first coil unit comprising a first head portion including the first bend portion formed on one side in the axial direction and a pair of first leg portions extending to the other side in the axial direction of the first head portion; a second coil unit comprising a second head portion including the second bend portion formed on one side in the axial direction and a pair of second leg portions extending to the other side in the axial direction of the second head portion and provided to be in contact with the other side in the axial direction of the first coil unit, wherein a first leg end portion which is an end portion of the first leg portion and a second leg end portion which is an end portion of the second leg portion are electrically connected.

[0025] In addition, the first coil unit and the second coil unit are configured to have the same length, and the second leg end is formed to protrude axially from the first leg end and is bent outward in the circumferential direction so that the side of the second leg end contacts the axial surface of the first leg end.

[0026] Additionally, the rail-type hairpin coil includes a welded portion for welding and connecting the first coil unit and the second coil unit, and the welded portion is formed at the area where the side of the second leg end and the axial opposite surface of the first leg end come into contact.

[0027] In addition, the welded portion is characterized as being on one side or the other side in the radial direction among the areas where the side of the second leg end and the axial other surface of the first leg end come into contact.

[0028] In addition, the welded portion is characterized as being the outer side in the circumferential direction among the areas where the side of the second leg end and the axial surface of the first leg end come into contact.

[0029] The above-described method for manufacturing a rail-type hairpin coil comprises: a first coil unit having the circumferential direction of the motor as the longitudinal direction, and a second coil unit positioned on the axial side of the first coil unit; a step of bending the first and second coil units to form first and second head portions on one axial side and forming a pair of first and second leg portions on the axial side; a step of bending a pair of second leg end portions protruding toward the axial side toward the circumferential outer side; and a step of welding the portion where the side of the second leg end portion and the axial side of the first leg end portion meet.

[0030] A rail-type hairpin coil according to one embodiment of the present invention, configured as described above, forms a hairpin coil by overlapping two windings, so it has the effect of drastically reducing the manufacturing time compared to the same number of turns of a motor using a general hairpin winding method.

[0031] In addition, the number of welding operations for each hairpin coil is significantly reduced, which has the effect of reducing the motor failure rate caused by welding defects.

[0032] In addition, since a pair is joined through a rail-type structure, it has the effect of preventing the coil unit from detaching during hairpin bending forming, thereby maintaining alignment.

[0033] In addition, when welding and joining two windings, the protrusion of one winding is bent toward the end of the other winding, and the joint surface of the bent portion is welded, which has the effect of improving welding precision.

[0034] FIG. 1 is a drawing illustrating a coil assembly with a hairpin winding method using a plurality of general hairpin coils.

[0035] FIG. 2 is a perspective view of a typical single-wound hairpin coil.

[0036] FIG. 3 is an enlarged perspective view illustrating the welded leg portion of a typical hairpin coil.

[0037] FIG. 4 is a perspective view of a rail-type hairpin coil with multiple windings according to an embodiment of the present invention.

[0038] FIG. 5 is a front view of a rail-type hairpin coil with multiple windings according to an embodiment of the present invention.

[0039] FIG. 6 is a cross-sectional view of a hairpin coil of the first embodiment of the present invention.

[0040] FIG. 7 is a cross-sectional view of a hairpin coil of a second embodiment of the present invention.

[0041] FIG. 8 is a cross-sectional view of a hairpin coil of a third embodiment of the present invention.

[0042] FIG. 9 is a perspective view of a rail-type hairpin coil according to another embodiment of the present invention.

[0043] FIGS. 10 to 12 are perspective views illustrating the manufacturing process of a hairpin coil according to another embodiment of the present invention.

[0044] FIG. 13 is a partial enlarged perspective view of a leg portion showing a welded portion according to a fourth embodiment of the present invention.

[0045] FIG. 14 is a partial enlarged perspective view of a leg portion showing a welded portion according to a fifth embodiment of the present invention.

[0046]

[0047] <Explanation of Symbols>

[0048] 100, 200, 300 : Hairpin coil

[0049] 110, 210, 310: 1st coil unit

[0050] 120, 220, 320: 2nd coil unit

[0051] 150, 250, 350 : Insulating member

[0052] 111: First depression

[0053] 112: First protrusion

[0054] 121: Second depression

[0055] 122 : Second protrusion

[0056] 211 : Protrusion

[0057] 221 : Homeboo

[0058] 311 : 1st Home

[0059] 321 : 2nd Home

[0060] 1100 : Hairpin coil

[0061] 1200 : 1st coil unit

[0062] 1210: 1st head section

[0063] 1220 : 1st Leg

[0064] 1250 : 1st leg section

[0065] 1300 : 2nd coil unit

[0066] 1310: 2nd head section

[0067] 1320 : 2nd Leg

[0068] 1350 : 2nd leg section

[0069] W1: 1st weld

[0070] W2: Second weld

[0071]

[0072] FIG. 4 shows a perspective view of a rail-type hairpin coil (100, 200, 300) of the first and third embodiments of the present invention, FIG. 5 shows a front view of a rail-type hairpin coil (100, 200, 300) of the first and third embodiments of the present invention, and

[0073] As described, the hairpin coil (100, 200, 300) can be formed by bending a rectangular coil having a predetermined length into a hairpin shape.

[0074] The present invention is characterized by applying a hairpin coil (100, 200, 300) having multiple windings to the space occupied by a conventional hairpin coil having a single winding. Therefore, various embodiments of a hairpin coil (100, 200, 300) having multiple windings will be described in detail below with reference to the drawings.

[0075]

[0076] FIG. 6 shows a cross-sectional view of a hairpin coil (100) of a first embodiment of the present invention. As shown, the hairpin coil (100) can be formed by combining a first coil unit (110) and a second coil unit (120).

[0077] As explained by defining the motor axis direction of the hairpin coil (100) as the z direction, which is orthogonal to the z direction, the circumferential direction of the motor as the x direction, which is orthogonal to both the z direction and the x direction, and the radial direction of the motor as the y direction, as illustrated, the other side of the first coil unit (110) in the x direction can be coupled with one side of the second coil unit (120) in the x direction.

[0078] At this time, the first coil unit (110) is formed on one side in the y direction (upper side in the drawing) and is configured to include a first recessed part (111) that is recessed from one side (left side in the drawing) on ​​the other side in the x direction (right side in the drawing) and a first protruding part (112) that is formed on the other side in the y direction (lower side in the drawing) and protrudes from the other side in the x direction.

[0079] Additionally, the second coil unit (120) is formed on one side in the y direction to be in contact with the first recess (111) and includes a second protrusion (122) protruding from one side in the x direction to one side, and includes a second recess (121) formed on the other side in the y direction to be in contact with the first protrusion (112) and recessed from one side in the x direction to the other side.

[0080] Meanwhile, the hairpin coil (100) may be configured with a plurality of windings, and an insulating member (150) may be provided between the first coil unit (110) and the second coil unit (120). The insulating member (150) may be provided on the joining surface of the first coil unit (110) and the second coil unit (120).

[0081] As another example, the insulating member (150) may be coated to wrap around the outer surface of the first coil unit (110) and the second coil unit (120).

[0082]

[0083] FIG. 7 shows a cross-sectional view of a hairpin coil (200) of a second embodiment of the present invention.

[0084] As described, the other side of the first coil unit (210) in the x direction can be combined with one side in the x direction of the second coil unit (220).

[0085] At this time, the first coil unit (210) is formed at the center in the y direction and is configured to include a projection (211) formed to protrude from the other side in the x direction.

[0086] Additionally, the second coil unit (220) is formed in the center of the y-direction so as to be in contact with the protrusion (211) and includes a groove (221) that is recessed from one side to the other in the x-direction.

[0087] Meanwhile, the hairpin coil (200) may be configured with a plurality of windings, and an insulating member (250) may be provided between the first coil unit (210) and the second coil unit (220). The insulating member (250) has the same configuration as the hairpin coil (100) of the first embodiment described above.

[0088]

[0089] FIG. 8 shows a cross-sectional view of a hairpin coil (300) of the third embodiment of the present invention.

[0090] As described, the other side of the first coil unit (310) in the x direction can be combined with one side in the x direction of the second coil unit (320).

[0091] At this time, the first coil unit (310) is formed in a 'C' shape with one side in the x direction open, is formed in the center of the y direction, and is configured to include a first groove (311) formed by sinking from one side in the x direction to the other.

[0092] Additionally, the second coil unit (220) is formed in a 'U' shape with the other side in the x direction open so that one side in the y direction is fitted into the first groove (311), and is configured to include a second groove (321) formed in the center of the y direction and recessed from the other side in the x direction to one side. The other side in the y direction of the first coil unit (310) is configured to be fitted into the second groove (321).

[0093] Meanwhile, the hairpin coil (300) may be configured with a plurality of windings, and an insulating member (350) may be provided between the first coil unit (310) and the second coil unit (320). The insulating member (250) has the same configuration as the hairpin coil (100) of the first embodiment described above.

[0094]

[0095] The hairpin coil (100)(200)(300) as described above has the effect of preventing separation of the first coil unit and the second coil unit and maintaining alignment by restricting movement in the y-direction during bending for hairpin coil forming.

[0096]

[0097] FIG. 9 shows a perspective view of a hairpin coil (1100) according to another embodiment of the present invention.

[0098] For convenience, the explanation defines the motor's axial direction as the z-direction, the circumferential direction as the x-direction, and the radial direction as the y-direction.

[0099] As described, the hairpin coil (1100) includes a first coil unit (1200) and a second coil unit (1300). The first coil unit (1200) and the second coil unit (1300) are formed in a combined form along the xz plane direction, the first coil unit (1200) is positioned on one side in the z direction, and the second coil unit (1300) is positioned on the other side in the z direction.

[0100] The first coil unit (1200) is provided on one side in the z-direction and includes a first head portion (1210) in which a first bend is formed, and a pair of first leg portions (1220) that extend from the other side in the z-direction of the first head portion (1210) to the other side.

[0101] The second coil unit (1300) is provided on one side in the z-direction and includes a second head portion (1310) in which a second bend is formed, and a pair of second leg portions (1320) that extend from the other side in the z-direction of the second head portion (1310) to the other side.

[0102] At this time, the first coil unit (1200) and the second coil unit (1300) are configured to have the same length as each other, and as the second coil unit (1300) is positioned on the other side of the first coil unit (1200) in the z-direction, that is, on the concave side of the first bending part, the other end of the second leg part (1320) may be formed to protrude further than the other end of the first leg part (1220), and the protruding other end (1350) of the second leg part (1320) may be bent outward in the x-direction so that one side contacts the other end of the first leg part (1220).

[0103] Accordingly, the other end (1350) of the bent second leg portion (1320) and the surface that contacts the other end of the first leg portion (1220) are configured to be welded.

[0104] In this case, since the first and second coil units (1200) (1300) can be easily aligned in the z and x directions before welding, the ease of welding is improved, and the welding precision can also be improved.

[0105] Meanwhile, although not shown in the drawings, the hairpin coil (1100) of the present invention may be formed with the same volume as a general hairpin coil. In this case, the thickness in the xz plane direction of the first and second coil units (1200) (1300) may be half of that of the present embodiment. When configured as above, there is an advantage that hairpin coils with twice the number of turns can be installed in the same space.

[0106] The manufacturing process and welding part of the hairpin coil (1100) as described above will be explained in detail below with reference to the drawings.

[0107]

[0108] FIGS. 10 to 12 show a perspective view illustrating the manufacturing process of a hairpin coil (1100) according to one embodiment of the present invention.

[0109] As shown in FIG. 10, the first coil unit (1200) and the second coil unit (1300) are arranged.

[0110] Since the first and second coil units (1200) (1300) have the same length and shape as each other, the cost and time for forming each of the first and second coil units (1200) (1300) can be reduced.

[0111] The first coil unit (1200) may be positioned on one side in the z-direction and the second coil unit (1300) may be positioned on the other side in the z-direction.

[0112] Next, as shown in FIG. 11, the first and second coil units (1200) (1300) are bent so that first and second bend portions are formed on one side in the z-direction. The bent first and second coil units (1200) (1300) have first and second head portions (1210) (1310) formed on one side and first and second leg portions (1220) (1320) formed on the other side.

[0113] At this time, as the second coil unit (1300) is placed and bent on the concave side of the first bending portion of the first coil unit (1200), the second end (1350) of the second leg portion (1320) is positioned to protrude in the z-direction opposite to the first end (1250) of the first leg portion (1220).

[0114] Next, as shown in FIG. 12, the second leg end (350) of the second leg portion (1320) is bent outward in the z-direction so that the side contacts the other side of the first leg end (1250) of the first leg portion (1220).

[0115] At this time, the welded portions of the first leg end (1250) and the second leg end (1350) are as follows.

[0116]

[0117] FIG. 13 shows an enlarged perspective view of the first and second leg end portions (1250) (1350) showing the first weld portion (W1) according to the fourth embodiment of the present invention.

[0118] As described, the second leg end (1350) is bent so that its side contacts the other side of the first leg end (1250), and the first weld (W1) is formed on the surface where the side of the second leg end (1350) and the other side of the first leg end (1250) contact, and may be formed on the outer or inner side in the y-direction, which is the radial direction of the motor.

[0119]

[0120] FIG. 14 shows an enlarged perspective view of the first and second leg end portions (1250) (1350) showing the second weld portion (W2) according to the fifth embodiment of the present invention.

[0121] As described, the second leg end (1350) is bent so that its side contacts the other side of the first leg end (250), and the first weld (W1) is formed on the surface where the side of the second leg end (1350) and the other side of the first leg end (1250) contact, and can be formed on the outer side in the x-direction, which is the circumferential direction of the motor.

[0122]

[0123] The technical concept of the present invention should not be interpreted as being limited to the embodiments described above. Not only is the scope of application diverse, but various modifications are possible at the level of a person skilled in the art without departing from the essence of the invention claimed in the claims. Therefore, such improvements and modifications fall within the scope of protection of the present invention insofar as they are obvious to a person skilled in the art.

Claims

1. In a hairpin coil wound on the stator of an electric motor, The above hairpin coil is, It is formed by the combination of multiple coil units, A rail-type hairpin coil having insulating members of an insulating material between multiple coil units.

2. In Paragraph 1, One of the above coil units includes one or more protrusions formed on the coupling surface, and Another of the above coil units is a rail-type hairpin coil comprising one or more grooves that are fitted into the above protrusion.

3. In Paragraph 1, The above coil unit includes a first coil unit and a second coil unit coupled to the first coil unit, and The other side in the width direction of the first coil unit and one side in the width direction of the second coil unit are joined together in contact, The above-mentioned first coil unit is, It includes a first recessed portion that is recessed from one side in the width direction to one side, and a first protrusion that is adjacent to the first recessed portion and protrudes from the other side in the width direction to the other side. The above second coil unit is, A rail-type hairpin coil comprising a second protrusion protruding from one side in the width direction to one side corresponding to the first recess, and a second recess recessed from one side in the width direction to the other side corresponding to the first protrusion.

4. In Paragraph 2, The above-mentioned protrusions and grooves are, A rail-shaped hairpin coil formed continuously along the longitudinal direction of the above hairpin coil.

5. In Paragraph 1, The above insulating member is, A rail-type hairpin coil having a predetermined thickness and provided between the joining surfaces of the plurality of coil units.

6. In Paragraph 1, The above insulating member is, A rail-type hairpin coil coated or applied to the outer surface of each of the above coil units with a predetermined thickness.

7. In Paragraph 1, The above coil unit includes a first coil unit and a second coil unit coupled to the first coil unit, and The first coil unit is formed in a 'U' shape including a first groove portion that is recessed from one side to the other in the width direction, and The above-mentioned second coil unit is formed in a 'U' shape including a second groove portion that is recessed from one side in the width direction to the other side, and A rail-type hairpin coil in which the other side in the thickness direction of the first coil unit is fitted into the first groove and the one side in the thickness direction of the second coil unit is fitted into the second groove so that the first coil unit and the second coil unit are interlocked and coupled with each other.

8. In a rail-type hairpin coil wound on the stator of an electric motor, The above rail-type hairpin coil is, A first coil unit comprising a first head portion including the first bend portion formed on one side in the axial direction and a pair of first leg portions extending to the other side in the axial direction of the first head portion, and A second bend portion is formed on one side in the axial direction, and the second coil unit includes a second head portion including the second bend portion and a pair of second leg portions extending to the other side in the axial direction of the second head portion, and is provided to abut the other side in the axial direction of the first coil unit. A rail-type hairpin coil in which the first leg end, which is the end of the first leg portion, and the second leg end, which is the end of the second leg portion, are electrically connected.

9. In Paragraph 8, The first coil unit and the second coil unit are A rail-type hairpin coil configured with equal lengths, wherein the second leg end is formed to protrude axially from the first leg end and is bent outward in the circumferential direction so that the side of the second leg end contacts the axial surface of the first leg end.

10. In Paragraph 9, The above rail-type hairpin coil is, It includes a welded portion for welding and connecting the first coil unit and the second coil unit, A rail-type hairpin coil, the welded portion being formed at the point where the side of the second leg end and the axial opposite surface of the first leg end meet.

11. In Paragraph 10, The above welded part is, A rail-type hairpin coil characterized by having one or the other side in the radial direction among the contact points between the side of the second leg end and the axial side of the first leg end.

12. In Paragraph 10, The above welded part is, A rail-type hairpin coil characterized by the circumferential outer side among the contact points between the side of the second leg end and the axial side of the first leg end.

13. In a method for manufacturing a rail-type hairpin coil according to any one of claims 8 to 12, A first coil unit having the circumferential direction of the motor as the longitudinal direction, and a second coil unit positioned on the other side of the first coil unit in the axial direction; A step of bending the first and second coil units to form first and second head portions on one side in the axial direction and forming a pair of first and second leg portions on the other side in the axial direction; A step of bending a pair of second leg ends protruding axially to the other side, each outwardly in the circumferential direction; and A step of welding the area where the side of the second leg end and the axial surface of the first leg end meet; A method for manufacturing a rail-type hairpin coil, comprising

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