Coil assembly, armature and rotating electric motor

Abstract

A coil assembly (32) comprises a plurality of strip elements (34) that are rolled or wound in a circumferential direction of the coil assembly. The strip elements have at least sections that overlap in a radial direction of the coil assembly and are stacked on top of each other in the radial direction of the coil assembly. The strip elements have a plurality of coils (16) arranged thereon. The coil assembly also has a thin-walled section (32B) and thick-walled sections (32A). The thin-walled section is defined by a portion of the strip elements and has a first thickness in the radial direction. The thick-walled sections (32A) are formed by portions of the strip elements and have a second thickness in the radial direction that is greater than the first thickness. The thick-walled sections are arranged circumferentially apart from one another.

Description

[0001] This application claims priority to Japanese Patent Application No. 2022-011872, filed on January 28, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical area

[0002] This disclosure generally relates to a coil assembly, an armature, and a rotating electric machine. STATE OF THE ART

[0003] The patent listed below describes a coil assembly that forms a portion of an armature installed in a rotating electrical machine. The coil assembly includes a first conductive cylinder, a second conductive cylinder, and an electrical insulator disposed between the first and second conductive cylinders. The first conductive cylinder is provided with a plurality of first conductive strips that extend in an axial direction of the first conductive cylinder and are arranged adjacent to and spaced from each other in a circumferential direction of the first conductive cylinder. Similarly, the second conductive cylinder is provided with a plurality of second conductive strips that extend in an axial direction of the second conductive cylinder and are arranged adjacent to and spaced from each other in a circumferential direction of the second conductive cylinder.The electrical insulator acts as an electrical insulator between the first conductive strips and the second conductive strips. This design allows the coil assembly to be designed simply and produced cost-effectively without compromising the electrical properties of the coil assembly. DOCUMENT OF THE PRIOR ART PATENT LITERATURE

[0004] PATENT LITERATURE: Japanese Patent First Publication No. 2017-070140 SUMMARY OF THE INVENTION

[0005] In a structure in which a coil assembly is arranged around the circumference of an armature core, it is advantageous to minimize the misalignment of the coil assembly with the armature core in its radial direction.

[0006] The object of this disclosure is to provide a coil assembly, an armature, and a rotating electric machine designed to minimize misalignment of the coil assembly with respect to an armature core in a radial direction.

[0007] According to one aspect of this disclosure, a coil assembly is provided comprising: (a) a plurality of strip elements made of an electrically insulating material, rolled in a circumferential direction of the coil assembly, and stacked on top of one another in a radial direction of the coil assembly, the strip elements having at least portions that overlap in the radial direction of the coil assembly; (b) a plurality of coils made of an electrically conductive material and formed on the strip elements, the coils being arranged in the circumferential direction; (c) thin-walled portions defined by portions of the strip elements and having a first thickness in the radial direction; and (d) a plurality of thick-walled portions defined by portions of the strip elements and having a second thickness in the radial direction that is greater than the first thickness.The thick-walled portions are arranged circumferentially spaced from each other. An armature for solving the above problem includes an armature core made of a soft magnetic material in a hollow cylindrical shape, and the above-described coil assembly disposed on either a radially outer peripheral surface or a radially inner peripheral surface of the armature core. A rotating electric machine for solving the above problem includes a first stator and a rotor including the above-described armature, and a second stator and rotor having magnets arranged to face the coil assembly in the radial direction.

[0008] The above structure makes it possible to minimize the misalignment of the coil assembly with respect to an armature core in its radial direction. SHORT DESCRIPTION OF THE DRAWINGS

[0009] The above-described object, other objects, features or advantageous advantages in this disclosure will become apparent from the following detailed discussion with reference to the drawings.

[0010] In the drawings: Fig. 1 is an elongated section of an electric motor in the axial direction in a first embodiment; Fig. 2 is a cross-sectional view of an electric motor in the radial direction of the motor in a first embodiment; Fig. 3 is a perspective view schematically illustrating a coil assembly; Fig. 4A is a plan view schematically illustrating a coil assembly equipped with rolled strip elements; Fig. 4B is a plan view schematically illustrating a coil assembly and a stator core; Fig. 5 is an explanatory view illustrating a star connection; Fig. 6 is a view illustrating the connections of a plurality of coils; Fig. Fig. 7 is a view schematically illustrating a coil; Fig. 8 is a schematic view partially illustrating a first combination of U-phase coils axially offset from other combinations of U-phase coils; Fig. 9 is a development view of a coil assembly; Fig. 10 is a section partially illustrating a coil assembly; Fig. 11 is a section partially illustrating a coil assembly; Fig. 12 is a section partially illustrating a coil assembly; Fig. 13 is a section of a coil assembly in the radial direction; Fig. 14 is a section that partially covers the Fig. 10 illustrated coil assembly provided with a second insulator layer; Fig. 15 is a section in which the Fig. 11 shown coil assembly provided with a second insulator layer is partially illustrated; Fig. 16 is a section that partially covers the Fig. 12 illustrated coil assembly provided with a second insulator layer; Fig. 17 is a plan view illustrating a coil assembly of an electric motor according to the second embodiment; Fig. 18 is a development view in which the coil assembly of Fig. 17 is illustrated; Fig. 19 is a schematic view partially illustrating a first combination of U-phase coils axially offset from other combinations of U-phase coils; Fig. 20 is a plan view illustrating a coil assembly of an electric motor according to the third embodiment; Fig. 21 is a development view in which the coil assembly of Fig. 20 is illustrated; Fig. 22 is a schematic view partially illustrating a first combination of U-phase coils axially offset from other combinations of U-phase coils; Fig. 23 is a plan view illustrating a coil assembly of an electric motor according to the fourth embodiment; Fig. 24 is a development view in which the coil assembly of Fig. 23 is illustrated; Fig. 25 is a schematic view partially illustrating a first combination of U-phase coils axially offset from other combinations of U-phase coils; Fig. 26 is a plan view illustrating a coil assembly of an electric motor according to the fifth embodiment; Fig. 27 is a development view in which the coil assembly of Fig. 26 is illustrated; Fig. 28 is a schematic view partially illustrating a first combination of U-phase coils axially offset from other combinations of U-phase coils; Fig. 29 is a perspective view illustrating a coil assembly of an electric motor according to the sixth embodiment; Fig. 30 is a development view in which the coil assembly of Fig. 29 is illustrated; Fig. 31 is a plan view illustrating a coil assembly and a stator core of an electric motor according to the seventh embodiment; Fig. 32 is a plan view illustrating a coil assembly and a stator core of an electric motor according to the eighth embodiment; Fig. 33 is a plan view illustrating a coil assembly of an electric motor; Fig. 34 is a plan view illustrating a coil assembly and an insulator incorporated in an electric motor according to the ninth embodiment; Fig. 35 is a plan view illustrating a coil assembly and an insulator incorporated in an electric motor according to the tenth embodiment; Fig. 36 is a plan view illustrating a coil assembly and an insulator incorporated in an electric motor according to the eleventh embodiment; Fig. 37 is a development view illustrating a coil assembly of an electric motor according to the twelfth embodiment; and Fig. 38 is a plan view showing the coil assembly of Fig. 37 is illustrated. METHOD FOR CARRYING OUT THE INVENTION FIRST EMBODIMENT

[0011] The electric motor 10 according to the first embodiment of this disclosure will be described below with reference to the Fig. 1 to 16. In the drawings, the directions expressed by arrows Z, R, and C correspond to a first direction, which is a rotational direction of an axis of the rotor 12, an outward radial direction of the rotor 12, and a first circumferential direction aligned along a circumference of the rotor 12, respectively. An axial direction, a radial direction, and a circumferential direction, which will be simply referred to hereinafter, correspond to an axial direction, a radial direction, and a circumferential direction of the rotor 12, unless otherwise specified. The motor 10 referred to in this disclosure is an example of a rotating electric machine.

[0012] The engine 10 is, as shown in the Fig. 1 and Fig. 2, is designed as a brushless internal rotor motor in which the rotor 12 is arranged radially inside the stator 14 serving as the armature. Fig. 1 and Fig. 2, the motor 10 is shown schematically for simplicity, therefore the number of coils 16 or magnets 18 or a detailed configuration of the motor 10 may differ from those discussed later.

[0013] The rotor 12 includes the rotating shaft 22, the rotor core 24, and the magnets 28. The rotating shaft 22 is rotatably supported by a pair of bearings 20. The rotor core 24 has a hollow cylindrical shape with a bottom and is fixed to the rotating shaft 22. The magnets 28 are fixed to a radial outer periphery of the rotor core 24.

[0014] The rotor core 24 includes the first cylinder 24A, the second cylinder 24B, and the connecting plate 24C. The first cylinder 24A has a hollow cylindrical shape, and the rotary shaft 22 is press-fitted therein. The second cylinder 24B has a hollow cylindrical shape and is arranged radially outside the first cylinder 24A. The connecting plate 24C is disc-shaped and connects the axial ends of the first cylinder 24A and the second cylinder 24B. The second cylinder 24B has a radial outer periphery that has a cylindrical shape and extends in the circumferential direction. The magnets 18 are attached to the outer periphery of the second cylinder 24B.

[0015] The magnets 18 are made of a magnetic compound having an intrinsic coercive force Hc of 400 kA / m or more and a remanent flux density Br of 1.0 T or more. Each of the magnets 18 is made of a magnetic compound made of NdFe, for example. 11 TiN, Nd2Fe 14B, Sm2Fe 17 N3 or FeNi. The magnets 18 are fixedly mounted on the outer circumference of the second cylinder 24B of the rotor core 24. The magnets 18 are divided into first magnets 18 and second magnets 18. Each of the first magnets 18 has an N pole on a radially outer surface. Each of the second magnets 18 has an S pole on a radially outer surface. The first and second magnets 18 are arranged alternately adjacent to each other in the circumferential direction. The number of magnets 18 depends on the output power required by the motor 10.

[0016] The stator 14 includes the hollow cylindrical stator core 26, which serves as the armature core, and the coil assembly 32, which is attached to the stator core 26. The stator 14 has, as shown in the Fig. 1 to 4B, a toothless structure in which a portion of the stator core 26 is not disposed within the coils 16 of the coil assembly 32.

[0017] The stator core 26 is, as shown in the Fig. 1 and Fig. 2, is annular or hollow cylindrical and is made of a soft magnetic material, such as steel. The stator core 26 is arranged coaxially with the rotor 12. In other words, the stator core 26 is arranged such that its central axis is aligned with that of an assembly of magnets 18 attached to the rotor core 24 in the axial direction of the rotor 12.

[0018] The coil assembly 32 comprises, as shown in Fig. 3 illustrates a plurality of strip elements 34 and coils 16. Each of the strip elements 34 has a circular shape and is made of an electrically insulating material. The coils 16 are made of an electrically conductive material and are formed on the strip elements 34.

[0019] Each of the strip elements 34, when extended, has a width in the axial direction of the rotor 12 and a length in a direction perpendicular to the axial direction. Each of the strip elements 34 has such a small thickness that it can be bent or rolled in the circumferential direction of the rotor 12. The coil assembly 32 comprises, as shown in Fig. 4A, the strip elements 34 are each bent or rolled into a closed circular shape. The coil assembly 32 comprises, in particular, three strip elements 34 that differ from one another in outer and inner diameters. One of the strip elements 34 is arranged radially inside the other, thereby completing a three-layer structure of the coil assembly 32 from a stack of the strip elements 34. In the following, a radially innermost one of the strip elements 34 is also referred to as the first strip element 34, a radially outermost one of the strip elements 34 is also referred to as the third strip element 34, and one of the strip elements 34 that is arranged between the first and third strip elements 34 is also referred to as the second strip element 34.

[0020] The coils 16 are, as in Fig. 3, is formed on the strip elements 34. The first and second strip elements 34 are, as shown in the Fig. 3 and Fig. 4A, are arranged radially inside the second and third strip elements 34, respectively, so that the coils 16 are arranged at preselected locations both in the circumferential direction and in the radial direction.

[0021] The coils 16 are, as in Fig. 5, the coil group 42U is divided into three groups: the U-phase coil group 42U, which generates a U phase, the V-phase coil group 42V, which generates a V phase, and the W-phase coil group 42W, which generates a W phase. The U-phase coil group 42U, the V-phase coil group 42V, and the W-phase coil group 42W are connected to each other in a star configuration. The U-phase coil group 42U includes the eighteen coils 16. The V-phase coil group 42V includes the eighteen coils 16. Similarly, the W-phase coil group 42W includes the eighteen coils 16.

[0022] In the following, the eighteen coils 16 of the U-phase coil group 42U are also referred to as coils U11, U12, U13, U21, U22, U23, U31, U32, U33, U41, U42, U43, U51, U52, U53, U61, U62 and U63.

[0023] The eighteen coils 16 of the V-phase coil group 42V are also referred to below as coils V11, V12, V13, V21, V22, V23, V31, V32, V33, V41, V42, V43, V51, V52, V53, V61, V62 and V63.

[0024] The eighteen coils 16 of the W-phase coil group 42W are also referred to below as coils W11, W12, W13, W21, W22, W23, W31, W32, W33, W41, W42, W43, W51, W52, W53, W61, W62 and W63.

[0025] In the following, the specified coil(s) 16 are designated only by the above-mentioned reference numerals.

[0026] Coils U11, U12, and U13 are connected in series. Coils U21, U22, and U23 are connected in series. Coils U31, U32, and U33 are connected in series. Coils U41, U42, and U43 are connected in series. Coils U51, U52, and U53 are connected in series. Coils U61, U62, and U63 are connected in series.

[0027] Coil U13 has a first end and a second end, the first end being connected to coil U12. Coil U23 has a first end and a second end, the first end being connected to coil U22. Coil U33 has a first end and a second end, the first end being connected to coil U32. Coil U43 has a first end and a second end, the first end being connected to coil U42. Coil U53 has a first end and a second end, the first end being connected to coil U52. Coil U63 has a first end and a second end, the first end being connected to coil U62. The second ends of coils U13, U23, U33, U43, U53, and U63 are connected to each other.

[0028] Coils V11, V12, and V13 are connected in series. Coils V21, V22, and V23 are connected in series. Coils V31, V32, and V33 are connected in series. Coils V41, V42, and V43 are connected in series. Coils V51, V52, and V53 are connected in series. Coils V61, V62, and V63 are connected in series.

[0029] The coil V13 has a first end and a second end, the first end being connected to the coil V12. The coil V23 has a first end and a second end, the first end being connected to the coil V22. The coil V33 has a first end and a second end, the first end being connected to the coil V32. The coil V43 has a first end and a second end, the first end being connected to the coil V42. The coil V53 has a first end and a second end, the first end being connected to the coil V52. The coil V63 has a first end and a second end, the first end being connected to the coil V62. The second ends of the coils V13, V23, V33, V43, V53 and V63 are connected to each other.

[0030] Coils W11, W12, and W13 are connected in series. Coils W21, W22, and W23 are connected in series. Coils W31, W32, and W33 are connected in series. Coils W41, W42, and W43 are connected in series. Coils W51, W52, and W53 are connected in series. Coils W61, W62, and W63 are connected in series.

[0031] The coil W13 has a first end and a second end, the first end being connected to the coil W12. The coil W23 has a first end and a second end, the first end being connected to the coil W22. The coil W33 has a first end and a second end, the first end being connected to the coil W32. The coil W43 has a first end and a second end, the first end being connected to the coil W42. The coil W53 has a first end and a second end, the first end being connected to the coil W52. The coil W63 has a first end and a second end, the first end being connected to the coil W62. The second ends of the coils W13, W23, W33, W43, W53 and W63 are connected to each other.

[0032] Coil U11 has a first end and a second end connected to coil U12. Coil V11 has a first end and a second end connected to coil V12. Coil W11 has a first end and a second end connected to coil W12. The first ends of coils U11, V11, and W11 are connected to each other.

[0033] Coil U21 has a first end and a second end connected to coil U22. Coil V21 has a first end and a second end connected to coil V22. Coil W21 has a first end and a second end connected to coil W22. The first ends of coils U21, V21, and W21 are connected to each other.

[0034] Coil U31 has a first end and a second end connected to coil U32. Coil V31 has a first end and a second end connected to coil V32. Coil W31 has a first end and a second end connected to coil W32. The first ends of coils U31, V31, and W31 are connected to each other.

[0035] Coil U41 has a first end and a second end connected to coil U42. Coil V41 has a first end and a second end connected to coil V42. Coil W41 has a first end and a second end connected to coil W42. The first ends of coils U41, V41, and W41 are connected to each other.

[0036] Coil U51 has a first end and a second end connected to coil U52. Coil V51 has a first end and a second end connected to coil V52. Coil W51 has a first end and a second end connected to coil W52. The first ends of coils U51, V51, and W51 are connected to each other.

[0037] Coil U61 has a first end and a second end connected to coil U62. Coil V61 has a first end and a second end connected to coil V62. Coil W61 has a first end and a second end connected to coil W62. The first ends of coils U61, V61, and W61 are connected to each other.

[0038] In Fig. Figure 7 schematically illustrates the U-phase coils 16. Viewed in the width direction of the strip elements 24, each of the coils 16 has a hexagonal shape and consists of three turns of conductor.

[0039] The coil U11 has a first, a second, and a third turn. The first turn of the coil U11 includes the first straight section A1, the second straight section A2, the third straight section A3, the fourth straight section A4, the fifth straight section A5, and the sixth straight section A6. In the following, an upper direction of the strip elements 34 (i.e., the rotor 12) as shown in Fig. 7, is also referred to as the first axial direction, while a lower direction is also referred to as the second axial direction. A direction to the right, as shown in Fig. 7, is also referred to as a first circumferential direction, while a direction to the left is also referred to as a second circumferential direction. The first straight section A1 extends obliquely in the second axial direction and is inclined in the second circumferential direction. The second straight section A2, which is continuous with the first straight section A1, extends straight in the second axial direction. The third straight section A3, which is continuous with the second straight section A2, extends obliquely in the second axial direction and is inclined in the first circumferential direction. The fourth straight section A4 extends obliquely from the third straight section A3 in the first axial direction and is inclined in the first circumferential direction. The fifth straight section A5 extends straight from the fourth straight section A4 in the first axial direction.The sixth straight section A6, which follows the fifth straight section A5, is inclined in the first axial direction and is inclined in the second circumferential direction.

[0040] The first straight section A1, the second straight section A2 and the third straight section A3 are on the first surface 34A (see Fig. 10) of a corresponding strip element 34. The straight section A4, the fifth straight section A5, and the sixth straight section A6 are formed on the second surface 34B of the corresponding strip element 34. The third straight section A3 and the fourth straight section A4 are electrically connected to each other via a through-hole formed in the strip element 34. The first, second, and third straight sections A1, A2, and A3 formed on the first surface 34A of the strip element 34 are represented by solid lines, while the fourth, fifth, and sixth straight sections A4, A5, and A6 formed on the second surface 34B of the strip element 34 are represented by dashed lines.

[0041] The second turn of the coil U11 includes the first straight section B1, the second straight section B2, the third straight section B3, the fourth straight section B4, the fifth straight section B5, and the sixth straight section B6. The first straight section B1 continues from the sixth straight section A6 of the first turn, extends obliquely in the second axial direction, and inclines in the second circumferential direction. The second straight section B2, which adjoins the first straight section B1, runs straight in the second axial direction. The third straight section B3, which adjoins the second straight section B2, runs obliquely in the second axial direction and is inclined in the first circumferential direction. The fourth straight section B4 extends obliquely from the third straight section B3 in the first axial direction and is inclined in the first circumferential direction.The fifth straight section B5 extends straight from the fourth straight section B4 in the first axial direction. The sixth straight section B6, which adjoins the fifth straight section B5, extends obliquely in the first axial direction and is oblique in the second circumferential direction. The sixth straight section B6 and the first straight section B1 are electrically connected to each other via a through-hole extending through the strip element 34. The third straight section B3 and the fourth straight section B4 are electrically connected to each other via a through-hole extending through the strip element 34.

[0042] The third turn of the coil U11 includes the first straight section C1, the second straight section C2, the third straight section C3, the fourth straight section C4, the fifth straight section C5, and the sixth straight section C6. The first straight section C1 continues from the sixth straight section B6 of the second turn, extends obliquely in the second axial direction, and inclines in the second circumferential direction. The second straight section C2, which adjoins the first straight section C1, runs straight in the second axial direction. The third straight section C3, which adjoins the second straight section C2, runs obliquely in the second axial direction and is inclined in the first circumferential direction. The fourth straight section C4 extends from the third straight section C3 obliquely in the first axial direction and is inclined in the first circumferential direction.The fifth straight section C5 extends straight from the fourth straight section C4 in the first axial direction. The sixth straight section C6, which adjoins the fifth straight section C5, extends obliquely in the first axial direction and is oblique in the second circumferential direction. The sixth straight section C6 and the first straight section C1 are electrically connected to each other via a through-hole that passes through the strip element 34. The third straight section C3 and the fourth straight section C4 are electrically connected to each other via a through-hole that passes through the strip element 34.

[0043] The second turn (i.e., the first straight section B1 to the sixth straight section B6) of coil U11 is offset from the first turn (i.e., the first straight section A1 to the sixth straight section A6) of coil U11 in the first circumferential direction. Similarly, the third turn (i.e., the first straight section C1 to the sixth straight section C6) is offset from the second turn (i.e., the first straight section B1 to the sixth straight section B6) of coil U11 in the first circumferential direction.

[0044] The U-phase coils U12 to U63 are, as shown in the Fig. 7 and Fig. 8, are shaped to have the same structures as coil U11. In other words, all U-phase coils U11 to U63 have the same structure. The second straight sections A2, B2, and C2 and the fifth straight sections A5, B5, and C5 are also called vertical sections 36. The first straight sections A1, B1, and C1 and the sixth straight sections A6, B6, and C6 are also called the first coil ends 38, while the third straight sections A3, B3, and C3 and the fourth straight sections A4, B4, and C4 are also called the second coil ends 38.

[0045] Fig. Figure 8 schematically illustrates coil U11 and coil U12, which are parts of the U-phase coils, as offset in the axial direction.

[0046] The fifth straight section A5, the fifth straight section B5 and the fifth straight section C5 of the coil U11 are located as shown in the Fig. 7 and Fig. 8 illustrates the second straight section A2, B2, and C2 of the coil U12, respectively, at the same locations in the circumferential direction. In other words, the fifth straight section A5, B5, and C5 of the coil U11 overlap with the second straight section A2, B2, and C2 of the coil U12, respectively, through the strip element 34.

[0047] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U12 are circumferentially arranged at the same positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U13, respectively. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U12 overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U13, respectively, through the strip element 34.

[0048] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U13 are circumferentially arranged at the same positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U23, respectively. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U13 overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U23, respectively, through the strip element 34.

[0049] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U23 are circumferentially arranged at the same positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U22, respectively. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U23 overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U22, respectively, through the strip element 34.

[0050] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U22 are circumferentially arranged at the same positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U21, respectively. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U22 overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U21, respectively, through the strip element 34.

[0051] As is apparent from the above, the coils U11, U12, U13, U23, U22 and U21 are mounted adjacent to each other in this order on the first strip element 34.

[0052] The sixth straight section C6 of coil U11 connects to the sixth straight section C6 of coil U12. The first straight section A1 of coil U12 connects to the first straight section A1 of coil U13. The sixth straight section C6 of coil U23 connects to the sixth straight section C6 of coil U22. The first straight section A1 of coil U22 connects to the first straight section A1 of coil U21. By this arrangement, the coils U11, U12, U13, U23, U22 and U21 physically form a coil (i.e., a left-side coil, which will be described in detail later) made by winding a conductor in one direction, but when they are electrically energized, the coils U11, U12, U13, U23, U22 and U21 play a role as a coil (i.e., a right-side coil) in which the coils U11, U13 and U21 are wound in a direction opposite to that in which the coils U12, U23 and U21 are wound.For simplicity, each of the coils U12, U23, and U21 will be referred to as the left-side coil, while each of the coils U11, U13, and U22 will be referred to as the right-side coil. Fig. 8, the right-side coils U11, U13, and U22 are indicated by overlines immediately above the reference numerals. In this embodiment, the left-side coils and the right-side coils are arranged alternately in the circumferential direction. In the following embodiments, the reference numerals U, V, and W, which represent the phases of the coils 16, are sometimes indicated by overlines.

[0053] Similar to the above, the fifth straight section A5, the fifth straight section B5 and the fifth straight section C5 of the coil U31 are arranged at the same positions as the second straight section A2, the second straight section B2 and the second straight section C2 of the coil U32 in the circumferential direction.

[0054] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U32 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U33. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U32 are arranged to overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U33, respectively, through the strip element 34.

[0055] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U33 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U43. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U33 are arranged to overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U43, respectively, through the strip element 34.

[0056] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U43 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U42. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U43 are arranged to overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U42, respectively, through the strip element 34.

[0057] The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U42 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U41. In other words, the fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U42 are arranged to overlap with the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U41, respectively, through the strip element 34.

[0058] As apparent from the above, the coils U31, U32, U33, U43, U42, and U41 are arranged adjacent to each other in this order on the second strip element 34. The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U21 on the first strip element 34 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U31 on the second strip element 34.

[0059] The coils U31, U32, U33, U43, U42 and U41 mounted on the second strip element 34 are connected to each other in the same way as the coils U11, U12, U13, U23, U22 and U21 mounted on the first strip element 34 are connected to each other

[0060] The coils U51 to U63 are arranged on the third strip element 34 in the same way as the coils U11 to U43 on the first and second strip elements 34. The coils U51, U52, U53, U63, U62, and U61 are therefore arranged in this order on the third strip element 34. The fifth straight section A5, the fifth straight section B5, and the fifth straight section C5 of the coil U41 mounted on the second strip element 34 are arranged at the same circumferential positions as the second straight section A2, the second straight section B2, and the second straight section C2 of the coil U51 mounted on the third strip element 34, respectively.

[0061] The coils U51, U52, U53, U63, U62 and U61 mounted on the third strip element 34 are connected to each other in the same way as the coils U11, U12, U13, U23, U22 and U21 mounted on the first strip element 34 are connected to each other.

[0062] The V-phase coils V11 to V63 are, as shown in the Fig. 8 and Fig. 9, the U-phase coils U11 to U63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34 in the same arrangements as the U-phase coils U11 to U63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34. Likewise, the W-phase coils W11 to W63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34 in the same arrangements as the U-phase coils U11 to U63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34. In contrast, the V-phase coils V11 to V63 are connected to each other such that the winding direction of the V-phase coils V11 to V63 is opposite to that of the U-phase coils U11 to U63 and the W-phase coils W11 to W63.

[0063] The V-phase coils V11 to V63 are offset from the U-phase coils U11 to U63 in the first circumferential direction. The W-phase coils W11 to W63 are offset from the V-phase coils V11 to V63 in the first circumferential direction.

[0064] Fig. 10 is a sectional view along the line AA in Fig. 9, which partially illustrates the first strip element 34 and the coils 16. In particular, Fig. 10 schematically shows an end of the first strip element 34 pointing in the second circumferential direction. The coils U11T1, U11T2, U11T3, V11T3, V11T2, V11T1, W11T1, W11T2 and W11T3 are, as in Fig. 10, are formed in this order on the first surface 34A of the first strip member 34. Note that "T1," "T2," or "T3" attached to the reference numeral for each coil represents a number for each turn. Specifically, "T1" represents the first turn. "T2" represents the second turn. "T3" represents the third turn. For example, "U11T1" indicates the first turn of the coil U11. "U11T2" indicates the second turn of the coil U11. "U11T3" indicates the third turn of the coil U11.

[0065] Fig. 11 is a line AA in Fig. 9, which partially illustrates the first strip element 34 and the coils 16. The Fig. 11 corresponds to a region of the first strip element 34 which is Fig. 9 is indicated by the arrow E. In the cross section in Fig. 11 is a section of the first strip element 34 which is circumferentially adjacent to the Fig. 10 illustrated section. Fig. 11 shows the coils U12T3, U12T2, U12T1, V12T1, V12T2, V12T3, W12T3, W21T2 and W12T1 formed on the first surface 34A of the strip member 34 in this order, and also shows the coils U11T1, U11T2, U11T3, V11T3, V11T2, V11T1, W11T1, W11T2 and W11T3 formed on the second surface 34B of the strip member 34 in this order.

[0066] Although not illustrated, the U-phase coils U12, U13, U23, U22 and U21, the V-phase coils V12, V13, V23, V22 and V21 and the W-phase coils W12, W13, W23, W22 and W21 are formed on the first and second surfaces 34A and 34B of the section of the strip element 34 in Fig. 11 in the same arrangement as in Fig. 11 illustrates the design.

[0067] Fig. 12 is a line along the AA in Fig. 9, which partially illustrates the first strip element 34 and the coils 16. The Fig. The section illustrated in Figure 12 corresponds to an end portion of the first strip element 34 facing the first circumferential direction. The coils U21T1, U21T2, U21T3, V21T3, V21T2, V21T1, W21T1, W21T2, and W21T3 are formed on the second surface 34B of the strip element 34 in this order.

[0068] Although not illustrated, the U-phase coils U31 to U41, the V-phase coils V31 to V41 and the W-phase coils W31 to W41 are provided on the first and second surfaces 34A and 34B of the strip member 34 in the same arrangement as in the Fig. 10 to 12. Similarly, the U-phase coils U51 to U61, the V-phase coils V51 to V61, and the W-phase coils W51 to W61 are formed on the first and second surfaces 34A and 34B of the strip element 34 in the same arrangement as in the Fig. 10 to 12 illustrates the design.

[0069] The coils 16 are, as in Fig. 9, are interconnected by means of structured connecting conductors 40, each of which is arranged at one of the axially opposite end portions of one of the strip elements 34. Some of the structured connecting conductors 40 arranged on the first surfaces 34A of the strip elements 34 are indicated by solid lines. Some of the structured connecting conductors 40 arranged on the second surface 34B of the strip elements 34 are indicated by dashed lines. Reference numeral "44" indicates a neutral point of the structured connecting conductors 40. Reference numeral "43" indicates portions of the structured connecting conductors 40 that serve as connection devices to a control device (not shown). The connections between the coils 16 and / or the conductors 40, 43 and 44 can be realized by busbars or produced by means of a printed circuit board.

[0070] The first strip element 34, as shown in the Fig. 4A, Fig. 9, Fig. 10 and Fig. 12, has a first end portion 34D and a second end portion 34C that are opposite to each other in the circumferential direction. The first and second end portions 34C and 34D overlap each other in the radial direction of the coil assembly 32. In particular, the first end portion 34D of the first strip element 34 is arranged radially outwardly of the second end portion 34C of the first strip element 34. The overlap between the first and second portions 34D and 34C of the first strip element 34 forms a connection therebetween and is hereinafter also referred to as an overlap 34E. A portion of the first strip element 34 that is not located in the overlap 34E is also referred to as a main portion 34F.In the first strip element 34 in which the first and second end portions 34D and 34C are connected to each other, the coils U11T1, U11T2, U11T3, V11T3, V11T2, V11T1, W11T1, W11T2 and W11T3 overlap with the coils U21T1, U21T2, U21T3, V21T3, V21T2, V21T1, W21T1, W21T2 and W21T3 in the radial direction.

[0071] The second strip element 34 has, as shown in the Fig. 4A and Fig. 9, a first end portion 34D and a second end portion 34C, which are opposite to each other in the circumferential direction. The first and second end portions 34C and 34D overlap each other in the radial direction of the coil assembly 32. In particular, the first end portion 34D of the second strip element 34 is arranged radially outwardly of the second end portion 34C of the second strip element 34. The overlap between the first and second end portions 34D and 34C of the second strip element 34 forms a connection between them and is also referred to below as the overlap 34E. In the second strip member 34 having the first and second end portions 34D and 34C connected to each other, the coils U31T1, U31T2, U31T3, V31T3, V31T2, V31T1, W31T1, W31T2 and W31T3 overlap with the coils U41T1, U41T2, U41T3, V41T3, V41T2, V41T1, W41T1, W41T2 and W41T3 in the radial direction of the coil assembly 32.The second strip element 34 has, as shown in . Fig. 4A, a central portion of its circumference is shaped as a convex portion 34G to prevent mechanical interference of the second strip element 34 in the circumferential direction with the first end portion 34D of the first strip element 34. The convex portion 34G bulges radially outward from a remaining portion of the second strip element 34. A portion of the second strip element 34 not including the overlap 34E and the convex portion 34G is also referred to as a main portion 34F.

[0072] The third strip element 34 has, as shown in the Fig. 4A and Fig. 9, a first end portion 34D and a second end portion 34C, which are opposite to each other in the circumferential direction. The first and second end portions 34C and 34D overlap each other in the radial direction of the coil assembly 32. In particular, the first end portion 34D of the third strip element 34 is arranged radially outwardly of the second end portion 34C of the second strip element 34. The overlap between the first and second end portions 34D and 34C of the second strip element 34 forms a joint therebetween and is also referred to below as the overlap 34E. In the third strip element 34, in which the first and second end portions 34D and 34C are connected to each other, the coils U51T1, U51T2, U51T3, V51T3, V51T2, V51T1, W51T1, W51T2 and W51T3 overlap with the coils U61T1, U61T2, U61T3, V61T3, V61T2, V61T1, W61T1, W61T2 and W61T3 in the radial direction of the coil assembly 32. The third strip element 34 has, as shown in Fig. 4A illustrates two portions of its periphery formed as first and second convex portions 34G to avoid circumferential mechanical interference of the third strip member 34 with the first end portion 34D and the convex portion 34G of the second strip member 34. Each of the first and second convex portions 34G of the third strip member 34 bulges radially outward from a remaining portion of the third strip member 34. A portion of the second strip member 34 excluding the overlap 34E and the first and second convex portions 34G is also referred to as a main portion 34F.

[0073] The overlaps 34E of the first strip element 34 and the second strip element 34 are, as shown in the Fig. 4A and Fig. 9, are spaced apart from each other at an interval of 120° in the circumferential direction. Similarly, the overlaps 34E of the second strip element 34 and the third strip element 34 are spaced apart from each other at an interval of 120° in the circumferential direction. Likewise, the overlaps 34E of the third strip element 34 and the first strip element 34 are spaced apart from each other at an interval of 120° in the circumferential direction. In other words, the overlaps 34E of the first, second, and third strip elements 34 are spaced apart from each other at equal intervals in the circumferential direction of the coil assembly 32.

[0074] The overlap 34E of the first strip element 34, the convex portion 34G of the second strip element 34 and the convex portion 34G of the third strip element 34 overlap, as shown in Fig. 4A, in the radial direction thereof to form the thick-walled portion 32A. The main portion 34F of the first strip member 34, the overlap 34E of the second strip member 34, and the convex portion 34G of the third strip member 34 overlap each other in the radial direction thereof to form the thick-walled portion 32A. Similarly, the main portion 34F of the first strip member 34, the main portion 34F of the second strip member 34, and the overlap 34E of the third strip member 34 overlap each other in the radial direction thereof to form the thick-walled portion 32A. In this embodiment, the three thick-walled portions 32A are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32.The main portion 34F of the first strip element 34, the main portion 34F of the second strip element 34, and the main portion 34F of the third strip element 34 overlap in the radial direction to form the thin-walled portion 32B. In this embodiment, the three thin-walled portions 32B are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32. The thick-walled portions 32A and the thin-walled portions 32B are arranged alternately in the circumferential direction. The thick-walled portions 32A have a greater thickness F1 in the radial direction of the coil assembly 32 than the thickness F2 of the thin-walled portions 32B. The coil assembly 32 also has stepped flanks 32C formed at a boundary between each of the thin-walled portions 32B and one of the thick-walled portions 32A and located near the stator core 26.Each of the flanks 32C extends radially outward from the thin-walled portion 32B toward the thick-walled portion 32A and has a height in the radial direction of the coil assembly 32. The above arrangements create a radially inner circumferential surface of the coil assembly 32 that is substantially flat or planar. In the coil assembly 32, which, as shown in FIG. Fig. 4B, is installed radially inside the stator core 26, the thick-walled portions 32A are arranged such that their radially outer surfaces are in direct or indirect contact with a radially inner surface of the stator core 26 via an insulator. The thin-walled portions 32B of the coil assembly 32 are arranged such that they have radially outer surfaces that oppose the radially inner surface of the stator core 26 through the recesses 33 therebetween. The first strip element 34 has, as shown in Fig. 4A, the first strip member 34 has electrical connecting means 43 extending therefrom. The second strip member 34 also has electrical connecting means 43 extending therefrom. The third strip member 34 also has electrical connecting means 43 extending therefrom. The electrical connecting means 43 are all located on the thin-walled portions 32B. The electrical connecting means 43 of the first strip member 34, the electrical connecting means 43 of the second strip member 34, and the electrical connecting means 43 of the third strip member 34 are arranged at regular intervals of 120° circumferentially from each other.

[0075] As is apparent from the above, in the coil assembly 32 in this embodiment, the three strip elements 34 are rolled or wound to create radially superimposed or stacked circuits so that the coils 16 are arranged at preselected locations both in the radial direction and in the circumferential direction of the coil assembly 32. In Fig. 13 illustrates a portion of a cross-section of the coil assembly 32, which consists of a stack of the three strip elements 34. The cross-section in Fig. 13 represents the vertical sections 36 of the coils 16 (see Fig. 7) and corresponds to one of the thin-walled sections 32B.

[0076] In the Fig. In the cross-section illustrated in Figure 13, the vertical sections 36 of the coils 16 are stacked one upon another in the radial direction of the coil assembly 32 and spaced apart from one another at equal intervals in the circumferential direction of the coil assembly 32. The first insulating layer 54A or the second insulating layer 54B is disposed between two radially adjacent vertical sections 36. Each of the first insulating layers 54A is realized by one of the strip elements 34 and is made of, for example, insulating paper or polyimide film.

[0077] The Fig. 14 to 16 correspond to the Fig. 10 to 12 illustrate cross-sections of the coil assembly 32 with the second insulating layer(s) 54B. The second insulating layers 54B are, as can be seen from the drawings, arranged on the strip elements 34 in the form of insulating foils and cover the coils 16. Each of the second insulating layers 54B can be made of an insulating coating material, e.g., polyimide material or varnish. For each of the strip elements 34, the second insulating layer 54B can be arranged either on the first surface 34A or on the second surface 34B, which, as shown in the Fig. 14 and Fig. 16 is not occupied by the coils 16. In the Fig. 14 and Fig. In the example illustrated in Figure 16, no second insulating layer 54B is disposed on the first surface 34A or the second surface 34B of each of the strip elements 34 that is not occupied by the coils 16.

[0078] The vertical sections 36 of the coils 16 are, as in Fig. 13, arranged so as to overlap one another in the radial direction of the coil assembly 32. Stacks of the vertical sections 36 in the radial direction are also referred to hereinafter as vertical section stacks 56. Viewed in radial cross-section, each of the vertical section stacks 56 has a rectangular shape having a dimension R1 in the radial direction (i.e., the thickness of the coil assembly 32) and a dimension S1 in the circumferential direction of the coil assembly 32 (i.e., the thickness of the vertical section stacks 56 defined in the circumferential direction). The dimension R1 is greater than the dimension S1. Each of the vertical sections 46 of the vertical section stacks 56 has a dimension (i.e., a width) S2 in the circumferential direction and a dimension (i.e., a thickness) R2 in the radial direction of the coil assembly 32. The dimension S2 is greater than the dimension R2.An interval W1 between any two adjacent vertical sections 36 in the circumferential direction gradually increases from the radial inner circumference to the radial outer circumference of the coil assembly 32, whereby the vertical sections 36 of each of the vertical section stacks 56 are arranged in a line, ie, are aligned with each other in the radial direction. The vertical section stacks 56 are therefore arranged to extend in the radial direction. FUNCTIONALITY AND BENEFICIAL EFFECTS OF THIS EMBODIMENT

[0079] The operation of this embodiment and the advantages that this embodiment offers are described below.

[0080] When operating the motor 10 in this embodiment, the Fig. 1, Fig. 2, Fig. 5 and Fig. 9, the U-phase coil group 42U, the V-phase coil group 42V, and the W-phase coil group 42W are sequentially excited to generate a rotating magnetic field within the stator 14, thereby causing the rotor 12 to rotate. The arrows iU in Fig. 9 indicate the directions in which electric currents flow through the vertical sections 36 of the coils 16.

[0081] In this embodiment, the coil assembly 32, as previously described, includes the three strip elements 34 and the coils 16. Each of the strip elements 34 is made of an electrically insulating material. The coils 16 are formed or arranged on the surfaces of the strip elements 34. This structure allows the coil assembly 32 to be designed to have a smaller size in the radial direction, resulting in a reduction in the overall size of the motor 10.

[0082] The coil assembly 32 is, as shown in Fig. 4A, the coil assembly 32 is configured such that the three thick-walled portions 32A are circumferentially spaced at equal intervals from one another, thereby minimizing the risk of undesired displacement of the coil assembly 32 relative to the stator core 26 when installed radially within the stator core 26. In particular, compared to the thick-walled portions 32A being formed only in a single region of the coil assembly 32, the arrangement in which the thick-walled portions 32A are spaced at equal intervals from one another minimizes misalignment of the coil assembly 32 with the stator core 26.One of the thick-walled portions 32A may be arranged such that at least a portion thereof is located at an angular interval of 180° from at least a portion of another of the thick-walled portions 32A in the circumferential direction of the coil assembly 32, so that they face or oppose each other in the radial direction of the coil assembly 32. This minimizes the misalignment of the coil assembly 32 with the stator core 26 in the radial direction of the coil assembly 32. Alternatively, at least a portion of one of the thick-walled portions 32A may be located at an angular interval of 180° from a region where at least two of the thick-walled portions 32A are successively adjacent in the circumferential direction of the coil assembly 32, thereby minimizing the misalignment of the coil assembly 32 with the stator core 26 in the radial direction of the coil assembly 32.

[0083] The coil assembly 32 in this embodiment is designed to have flanks 32C located at the boundary between each of the thin-walled portions 32B and one of the thick-walled portions 32A and facing the stator core 26. Each of the flanks 32C extends radially outward from the thin-walled portion 32B toward the thick-walled portion 32A. In other words, the coil assembly 32 has no flanks 32C on its inner periphery facing the magnets 18 of the rotor 12. This structure allows the distances between the inner circumference of the coil assembly 32 and the outer circumferences of the magnets 18 to be uniform, compared to the case where the coil assembly 32 also has the flanks 32C facing the magnets 18 of the rotor 12, resulting in uniformity of the torque generated by the motor 10.

[0084] Each of the vertical section stacks 56 has, as already described with reference to Fig. 13, a dimension R1 in the radial direction that is greater than its dimension S1 in the circumferential direction of the coil assembly 32. This allows the vertical section stacks 56 to be shaped such that the areas of the vertical section stacks 56 facing the magnets 18 of the rotor 12 are reduced without sacrificing required cross-sectional areas thereof, which minimizes the risk that radial magnetic flux can generate an eddy current in the vertical section stacks 56. This increases the torque generated by the motor 10.

[0085] Each of the vertical sections 36 of the vertical section stacks 56 is shaped such that its circumferential dimension S2 is greater than its radial dimension R2. This minimizes the risk that the magnetic flux penetrating a gap between two adjacent magnets 18 of the rotor 12 will generate an eddy current in the vertical section stacks 56, thereby increasing the torque output by the motor 10. The thick-walled section 32A, the thin-walled section 32B, or the electrical connecting devices 43 are, as described above, arranged at equal intervals from one another in the circumferential direction of the coil assembly 32, but may alternatively be arranged at irregular intervals from one another. The interval W1 between any two adjacent vertical sections 36 in the circumferential direction is, as shown in Fig. 13, the interval W1 is chosen to increase from the inner circumference to the outer circumference of the coil assembly 32, however, the interval W1 can be kept substantially constant as long as the dimension S2 of each of the vertical sections 36 is chosen to increase radially outward. With this geometry of the coil assembly 32, each of the vertical section stacks 56 is fan-shaped, allowing the conductor of each of the coils 16 to have an increased cross-sectional area, increasing the torque generated by the motor 10. SECOND EXAMPLE

[0086] An electric motor according to the second embodiment will be described below. The same reference numerals as in the first embodiment refer to the same or similar parts, and a detailed explanation is omitted here.

[0087] The motor in this embodiment is equipped with the Fig. 17 and Fig. 18. The coil assembly 32 includes the first strip element 34, the second strip element 34, and the coils 16 formed on the surfaces of the first and second strip elements 34.

[0088] Fig. 19 corresponds to Fig. 8 illustrates the U-phase coils 16 arranged on the first strip member 34 and the second strip member 34. An assembly of the coils U11, U12, U13, U23, U22, and U21 arranged on the first strip member 34 differs in the locations of the electrical connection device(s) 43 and the neutral point(s) 44 from those of the motor 10 of the first embodiment. The right-side coil and the left-side coil in this embodiment are inversely related to those of the first embodiment. Other arrangements are identical and will not be explained in detail here. The coils U31, U32, U33, U43, U42, and U41 formed on the second strip member 34 are structurally identical to those of the motor 10 in the first embodiment.

[0089] The V-phase coils V11 to V43 are arranged on the first strip element 34 and the second strip element 34 in the same arrangement as the coils U11 to U43. Likewise, the W-phase coils W11 to W43 are arranged on the first strip element 34 and the second strip element 34 in the same arrangement as the coils U11 to U43.

[0090] The overlap 34E of the first strip element 34 is, as in Fig. 17, are arranged circumferentially of the coil assembly 32 at an angular interval of 180° from the overlap 34E of the second strip element 34. In other words, the overlaps 34E of the strip elements 34 are arranged circumferentially at equal intervals from each other.

[0091] The electrical connection devices 43 extending from the first strip element 34 and the electrical connection devices 43 extending from the second strip element 34 are, as shown in the Fig. 17 and Fig. 18, are arranged so as to coincide with each other in the circumferential direction of the coil assembly 32. Specifically, a circumferential position of the electrical connector 42 extending from the first strip member 34 coincides with that of the connector 43 extending from the second strip member 34. Similarly, a circumferential position of the electrical connector 42 extending from the first strip member 34 is arranged so as to coincide with that of the connector 43 extending from the second strip member 34. Similarly, a circumferential position of the W-phase electrical connector 42 extending from the first strip member 34 coincides with that of the W-phase connector 43 extending from the second strip member 34.The electrical connection devices 43 extending from the first and second strip elements 34 are all located on one of the thick-walled sections 32A.

[0092] In the coil assembly 32 of the motor in the second embodiment, as described above, the two thick-walled portions 32A are circumferentially spaced at equal intervals from each other. This arrangement minimizes the risk of radial misalignment of the coil assembly 32 with the stator core 26 when the coil assembly 32 is installed radially inside the stator core 26.

[0093] In this embodiment, as described above, the coil assembly 32 is designed such that the electrical connection devices 43 extending from the first strip element 34 are arranged congruently with those extending from the second strip element 34 in the circumferential direction of the coil assembly 32. This eliminates the need for additional parts used to connect the electrical connection devices 43 of the same phase. THIRD EXAMPLE

[0094] An electric motor according to the third embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0095] The coil assembly 32 of the motor in this embodiment comprises, as shown in the Fig. 20 and Fig. 21 illustrates the first strip element 34, the second strip element 34, the third strip element 34 and the coils 16 formed on the first to third strip elements 34.

[0096] Fig. 22 corresponds to Fig. 8 illustrates the U-phase coils 16 formed on the first strip member 34, the second strip member 34, and the third strip member 34. An assembly of the coils U11, U12, U13, U23, U22, and U21 arranged on the first strip member 34 differs in the locations of the electrical connection device(s) 43 and the neutral point(s) 44 from that of the motor 10 in the first embodiment. The coils U31, U32, U33, U43, U42, and U41 formed on the second strip member 34 are in an inverse relationship of the right-side coil and the left-side coil to those of the first embodiment. Other arrangements are identical to those of the motor 10 in the first embodiment.An assembly of the coils U51, U52, U53, U63, U62 and U61 arranged on the third strip element 34 is identical in structure to that of the coils U31, U32, U33, U43, U42 and U41 formed on the second strip element 34 in this embodiment, except that the locations of the electrical connection device(s) 43 and the neutral point(s) 44 differ from those of the coils U31, U32, U33, U43, U42 and U41 formed on the second strip element 34 in this embodiment.

[0097] The V-phase coils V11 to V63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34 in the same arrangement as the U-phase coils U11 to U63. Similarly, the W-phase coils W11 to W63 are arranged on the first strip element 34, the second strip element 34, and the third strip element 34 in the same arrangement as the U-phase coils U11 to U63.

[0098] The electrical connecting means 43 extending from the first strip element 34, the electrical connecting means 43 extending from the second strip element 34, and the electrical connecting means 43 extending from the third strip element 34 coincide in the circumferential direction of the coil assembly 32, as shown in the Fig. 20 and Fig. 21. The electrical connection devices 43 extending from the first, second, and third strip elements 34 are all located on one of the thick-walled sections 32A.

[0099] In the coil assembly 32 of the motor in the third embodiment, as described above, the three thick-walled portions 32A are circumferentially spaced at equal intervals from each other. This arrangement minimizes the risk of radial misalignment of the coil assembly 32 with the stator core 26 when the coil assembly 32 is installed radially inside the stator core 26.

[0100] In this embodiment, as described above, the coil assembly 32 is designed such that the electrical connecting devices 43 extending from the first strip element 34 are arranged congruently with those extending from the second and third strip elements 34 in the circumferential direction of the coil assembly 32. This eliminates the need for additional parts used to connect the electrical connecting devices 43 of the same phase. FOURTH EXAMPLE

[0101] An electric motor according to the fourth embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0102] The coil assembly 32 of the motor in this embodiment comprises, as shown in the Fig. 23 and Fig. 24 illustrates the first strip element 34, the second strip element 34, the third strip element 34, the fourth strip element 34, and the coils 16 formed on the first to fourth strip elements 34.

[0103] The coil assembly 32 comprises, as shown in the Fig. 24 and Fig. 25, the 32 U-phase coils 16, the 32 V-phase coils 16 and the 32 V-phase coils 16, which are connected together in the form of a star connection.

[0104] The U-phase coils 16 include the coils U11, U12, U13, U14, U21, U22, U23, U24, U31, U32, U33, U34, U41, U42, U43, U44, U51, U52, U53, U54, U61, U62, U63, U64, U71, U72, U73, U74, U81, U82, U83, and U84.

[0105] Likewise, the V-phase coils 16 include the coils V11, V12, V13, V14, V21, V22, V23, V24, V31, V32, V33, V34, V41, V42, V43, V44, V51, V52, V53, V54, V61, V62, V63, V64, V71, V72, V73, V74, V81, V82, V83 and V84.

[0106] Likewise, the W-phase coils 16 include the coils W11, W12, W13, W14, W21, W22, W23, W24, W31, W32, W33, W34, W41, W42, W43, W44, W51, W52, W53, W54, W61, W62, W63, W64, W71, W72, W73, W74, W81, W82, W83 and W84.

[0107] In the following, the specified coil(s) 16 are designated only by the above-mentioned reference numerals.

[0108] Coils U11, U12, U13, and U14 are connected in series. Coils U21, U22, U23, and U24 are connected in series. Coils U31, U32, U33, and U34 are connected in series. Coils U41, U42, U43, and U44 are connected in series. Coils U51, U52, U53, and U54 are connected in series. Coils U61, U62, U63, and U64 are connected in series. Coils U71, U72, U73, and U74 are connected in series. Coils U81, U82, U83, and U84 are connected in series.

[0109] Coils U11 have a first end connected to coils U12 and a second end opposite the first end. Coil U24 has a first end connected to coils U23 and a second end opposite the first end. Coil U34 has a first end connected to coil U33 and a second end opposite the first end. Coil U41 has a first end connected to coil U42 and a second end opposite the first end. Coil U54 has a first end connected to coil U53 and a second end opposite the first end. Coil U61 has a first end connected to coil U62 and a second end opposite the first end. Coil U74 has a first end connected to coil U73 and a second end opposite the first end.Coil U81 has a first end connected to coil U82 and a second end opposite the first end. The second ends of coils U11, U24, U34, U41, U54, U61, U74, and U81 are configured as electrical connectors 43 that are connected to each other.

[0110] The V-phase coils V11 to V84 are connected in the same way as the U-phase coils U11 to U84. The W-phase coils W11 to W84 are connected in the same way as the U-phase coils U11 to U84.

[0111] Coil U14 has a first end connected to coil U13 and a second end opposite the first end. Coil V14 has a first end connected to coil V13 and a second end opposite the first end. Coil W14 has a first end connected to coil W13 and a second end opposite the first end. The second ends of coils U14, V14, and W14 are connected together at neutral point 44.

[0112] Coil U21 has a first end connected to coil U22 and a second end opposite the first end. Coil V21 has a first end connected to coil V22 and a second end opposite the first end. Coil W21 has a first end connected to coil W22 and a second end opposite the first end. The second ends of coils U21, V21, and W21 are connected together at neutral point 44.

[0113] Coil U31 has a first end connected to coil U32 and a second end opposite the first end. Coil V31 has a first end connected to coil V32 and a second end opposite the first end. Coil W31 has a first end connected to coil W32 and a second end opposite the first end. The second ends of coils U31, V31, and W31 are connected together at neutral point 44.

[0114] Coil U44 has a first end connected to coil U43 and a second end opposite the first end. Coil V44 has a first end connected to coil V43 and a second end opposite the first end. Coil W44 has a first end connected to coil W43 and a second end opposite the first end. The second ends of coils U44, V44, and W44 are connected together at neutral point 44.

[0115] Coil U51 has a first end connected to coil U52 and a second end opposite the first end. Coil V51 has a first end connected to coil V52 and a second end opposite the first end. Coil W51 has a first end connected to coil W52 and a second end opposite the first end. The second ends of coils U51, V51, and W51 are connected together at neutral point 44.

[0116] Coil U64 has a first end connected to coil U63 and a second end opposite the first end. Coil V64 has a first end connected to coil V63 and a second end opposite the first end. Coil W64 has a first end connected to coil W63 and a second end opposite the first end. The second ends of coils U64, V64, and W64 are connected together at neutral point 44.

[0117] Coil U71 has a first end connected to coil U72 and a second end opposite the first end. Coil V71 has a first end connected to coil V72 and a second end opposite the first end. Coil W71 has a first end connected to coil W72 and a second end opposite the first end. The second ends of coils U71, V71, and W71 are connected together at neutral point 44.

[0118] Coil U84 has a first end connected to coil U83 and a second end opposite the first end. Coil V84 has a first end connected to coil V83 and a second end opposite the first end. Coil W84 has a first end connected to coil W83 and a second end opposite the first end. The second ends of coils U84, V84, and W84 are connected together at neutral point 44.

[0119] Coils U11 to U24 are arranged in this order on the first strip element 34. Coils U31 to U44 are arranged in this order on the second strip element 34. Coils U51 to U64 are arranged in this order on the third strip element 34. Coils U71 to U84 are arranged in this order on the fourth strip element 34.

[0120] The V-phase coils V11 to V84 are, as shown in the Fig. 24 and Fig. 25, the first strip element 34, the second strip element 34, the third strip element 34, and the fourth strip element 34 are arranged in the same arrangement as the U-phase coils U11 to U84. Likewise, the W-phase coils W11 to W84 are arranged on the first strip element 34, the second strip element 34, the third strip element 34, and the fourth strip element 34 in the same arrangement as the U-phase coils U11 to U84.

[0121] In this embodiment, the four thick-walled sections 32A, as shown in Fig. 23, the four thin-walled portions 32A and 32B are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32. Likewise, the four thin-walled portions 32B are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32. The thick-walled portions 32A and the thin-walled portions 32B are arranged alternately in the circumferential direction of the coil assembly 32.

[0122] The electrical connection devices 43 extending from the first strip element 34, the electrical connection devices 43 extending from the second strip element 34, the electrical connection devices 43 extending from the third strip element 34 and the electrical connection devices 43 extending from the fourth strip element 34 fall, as shown in the Fig. 23 and Fig. 24, each of the strip elements 34 engages with one another in the circumferential direction of the coil assembly 32. The electrical connection devices 43 extending from the first, second, third, and fourth strip elements 34 are all located on one of the thick-walled sections 32A.

[0123] In the coil assembly 32 of the motor in the fourth embodiment, as described above, the four thick-walled portions 32A are circumferentially spaced at equal intervals from each other. This arrangement minimizes the risk of radial misalignment of the coil assembly 32 with the stator core 26 when the coil assembly 32 is installed radially inside the stator core 26.

[0124] In this embodiment, as described above, the coil assembly 32 is constructed such that the electrical connection devices 43 extending from the first strip element 34 are arranged in the circumferential direction of the coil assembly 32 so as to coincide with those extending from the second, third, and fourth strip elements 34. This eliminates the need for additional parts for connecting the electrical connection devices 43 of the same phase. FIFTH EXAMPLE

[0125] An electric motor according to the fifth embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanations will be omitted here.

[0126] The coil assembly 32 of the motor in this embodiment, as shown in the Fig. 26 and Fig. 27, comprises the 1.5 (ie, one and a half) turn strip member 34 and a 1.5 to 3 turn strip member 34, and the coils 16 formed on the 1.5 turn strip member 34 and the 1.5 to 3 turn strip member 34.

[0127] The coil assembly 32 comprises, as shown in the Fig. 27 and Fig. 28 illustrates 18 U-phase coils 16, 18 V-phase coils 16 and 18 W-phase coils 16 connected together in the form of a star connection.

[0128] Coils U11, U12, and U13 are connected in series. Coils U21, U22, and U23 are connected in series. Coils U31, U32, and U33 are connected in series. Coils U41, U42, and U43 are connected in series. Coils U51, U52, and U53 are connected in series. Coils U61, U62, and U63 are connected in series.

[0129] Coils U11 have a first end connected to coils U12 and a second end opposite the first end. Coil U21 has a first end connected to coils U22 and a second end opposite the first end. Coil U31 has a first end connected to coil U32 and a second end opposite the first end. Coil U43 has a first end connected to coil U42 and a second end opposite the first end. Coil U53 has a first end connected to coil U52 and a second end opposite the first end. Coil U63 has a first end connected to coil U62 and a second end opposite the first end. The second ends of the coils U11, U21, U31, U43, U53 and U63 are formed as electrical connecting devices 43 which are connected to each other.

[0130] The V-phase coils V11 to V63 are connected in the same way as the U-phase coils U11 to U63. The W-phase coils W11 to W63 are connected in the same way as the U-phase coils U11 to U63.

[0131] Coil U13 has a first end connected to coil U12 and a second end opposite the first end. Coil V13 has a first end connected to coil V12 and a second end opposite the first end. Coil W13 has a first end connected to coil W12 and a second end opposite the first end. The second ends of coils U13, V13, and W13 are connected together at neutral point 44.

[0132] Coil U23 has a first end connected to coil U22 and a second end opposite the first end. Coil V23 has a first end connected to coil V22 and a second end opposite the first end. Coil W23 has a first end connected to coil W22 and a second end opposite the first end. The second ends of coils U23, V23, and W23 are connected together at neutral point 44.

[0133] Coil U3 has a first end connected to coil U32 and a second end opposite the first end. Coil V33 has a first end connected to coil V32 and a second end opposite the first end. Coil W33 has a first end connected to coil W32 and a second end opposite the first end. The second ends of coils U33, V33, and W33 are connected together at neutral point 44.

[0134] Coil U41 has a first end connected to coil U42 and a second end opposite the first end. Coil V41 has a first end connected to coil V42 and a second end opposite the first end. Coil W41 has a first end connected to coil W42 and a second end opposite the first end. The second ends of coils U41, V41, and W41 are connected together at neutral point 44.

[0135] Coil U51 has a first end connected to coil U52 and a second end opposite the first end. Coil V51 has a first end connected to coil V52 and a second end opposite the first end. Coil W51 has a first end connected to coil W52 and a second end opposite the first end. The second ends of coils U51, V51, and W51 are connected together at neutral point 44.

[0136] Coil U61 has a first end connected to coil U62 and a second end opposite the first end. Coil V61 has a first end connected to coil V62 and a second end opposite the first end. Coil W61 has a first end connected to coil W62 and a second end opposite the first end. The second ends of coils U61, V61, and W61 are connected together at neutral point 44.

[0137] The U-phase coils U11, U12, U13, U23, U22, U21, U31, U32, and U33 are arranged on the strip element 34 with 1.5 turns in this order. The U-phase coils U41, U42, U43, U53, U52, U51, U61, U62, and U63 are arranged on the strip element 34 with 1.5 to 3 turns in this order.

[0138] The V-phase coils V11 to V63 are, as shown in the Fig. 27 and Fig. 28, the U-phase coils W11 to W63 are arranged on the 1.5-turn strip element 34 and the 1.5- to 3-turn strip element 34 in the same arrangement as the U-phase coils U11 to U63. The W-phase coils W11 to W63 are arranged on the 1.5-turn strip element 34 and the 1.5- to 3-turn strip element 34 in the same arrangement as the U-phase coils U11 to U63.

[0139] The two thick-walled sections 32A are, as shown in Fig. 26, the two thin-walled portions 32A are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32. Similarly, the two thin-walled portions 32B are arranged at equal intervals from each other in the circumferential direction of the coil assembly 32. The thick-walled portions 32A and the thin-walled portions 32B are arranged alternately in the circumferential direction.

[0140] The electrical connection devices 43 extending from the strip element 34 with 1.5 turns and the electrical connection devices 43 extending from the strip element 34 with 1.5 to 3 turns fall, as shown in the Fig. 26 and Fig. 27, in the circumferential direction of the coil assembly 32. The electrical connection devices 43 extending from the strip element 34 with 1.5 to 3 turns and the electrical connection devices 43 extending from the strip element 34 with 1.5 to 3 turns are all located on one of the thick-walled portions 32A.

[0141] In the coil assembly 32 of the motor in the fifth embodiment, as described above, the two thick-walled portions 32A are circumferentially spaced at equal intervals from each other. This arrangement minimizes the risk of radial misalignment of the coil assembly 32 with the stator core 26 when the coil assembly 32 is installed radially inside the stator core 26.

[0142] As described above, the electrical connecting devices 43 extending from the 1.5-turn strip element 34 and the electrical connecting devices 43 extending from the 1.5- to 3-turn strip element 34 are arranged congruently with each other in the circumferential direction of the coil assembly 32. This eliminates the need for additional parts used to connect the electrical connecting devices 43 of the same phase. SIXTH EXAMPLE

[0143] An electric motor according to the sixth embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0144] The coil assembly 32 has in this embodiment, as shown in the Fig. 29 and Fig. 30 illustrates a plurality of recesses 34H formed in a first circumferential end and a second circumferential end of each of the strip elements 34, which are opposite to each other in the axial direction of the coil assembly 32. Each of the recesses 34H has a rectangular shape as viewed in the radial direction of the coil assembly 32. In other words, each of the recesses 34H is U-shaped with an opening directed in the first axial direction (i.e., upward, as shown in Fig. 29) or in the second axial direction (ie downwards, as in Fig. 29) opposite to the first axial direction. Each of the recesses 34H is offset from an adjacent one of the second straight sections A2 of the U-phase coils 16 by an angle α° in the first circumferential direction.

[0145] The positioning of the second strip element 34 relative to the first strip element 34 or the positioning of the third strip element 34 relative to the second strip element 34 in the circumferential direction is achieved by the stator core 26, an element fastened to the stator core 26, or projections of a machining tool with which the strip elements 34 are formed into a hollow cylinder, engaging in the recesses 34H formed in the first strip element 34, the second strip element 34, and the third strip element 34. This also ensures the positioning of the coils 16 formed on the strip elements 34 in the circumferential direction. SEVENTH AND EIGHTH EXAMPLES

[0146] Electric motors according to the seventh and eighth embodiments will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0147] The engine in the seventh embodiment, as in Fig. 31, includes the stator 14, in which the adhesive 70 is disposed in each of the recesses 33 defined between the outer peripheral surfaces of the thin-walled portions 32B of the coil assembly 32 and an inner peripheral surface of the stator core 26. The adhesive 70 serves to establish a firm connection between the stator core 26 and the coil assembly 32.

[0148] The above structure of the seventh embodiment allows the adhesive 70 applied to the inner peripheral surface of the stator core 26 or the outer peripheral surface of the coil assembly 32 to remain accumulated in the recesses 33 when the coil assembly 32 is inserted into the stator core 26, thereby ensuring the stability of the mechanical connection between the stator core 26 and the coil assembly 32.

[0149] The coil assembly 32 in this embodiment can be like the motor in the second embodiment (see Fig. 17) may be designed such that the electrical connecting devices 43 are arranged in one of the thick-walled sections 32A, thereby minimizing the risk that at least part of the adhesive 70 emerging from the recesses 33 remains adhered to the electrical connecting devices 43.

[0150] Fig. 32 illustrates the stator 14 incorporated in the motor according to the eighth embodiment. The motor in this embodiment is configured as an external rotor electric motor, in which the coil assembly 32 is disposed on an outer periphery of the stator core 26. The stator 14 includes the adhesive 70 in each of the recesses 33 defined between inner peripheral surfaces of the thin-walled portions 32B of the coil assembly 32 and an outer peripheral surface of the stator core 26. The adhesive 70 serves to firmly bond the stator core 26 and the coil assembly 32.

[0151] The engine of the eighth embodiment offers essentially the same advantages as that of the seventh embodiment.

[0152] The coil assembly 32 can, as in Fig. 33, the coil assembly 32 may be configured such that the recesses 33 are present either when the coil assembly 32 is disposed on the outer peripheral surface of the stator core 26 or when the coil assembly 32 is disposed on the inner peripheral surface of the stator core 26. In other words, the coil assembly 32 may be configured for use in either outer-rotor motors or inner-rotor motors. NINTH EXAMPLE

[0153] An electric motor according to the ninth embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0154] The engine in this embodiment, as shown in Fig. 34, comprises the insulator 28 made of an electrically insulating material. The insulator 28 is arranged between the outer peripheral surface of the coil assembly 32 and the inner peripheral surface of the stator core 26 (see Fig. 4B).

[0155] The insulator 28 has a rectangular shape with a width in the axial direction of the coil assembly 32 and a length extending in a direction perpendicular to the axial direction of the coil assembly 32. The thickness of the insulator 28 is so small that it is curved in its longitudinal direction (i.e., in the circumferential direction of the coil assembly 32). The thickness of the insulator 28 is selected, for example, to be identical to or greater than the thickness of the strip elements 34. However, the thickness of the insulator 28 may also be selected to be smaller than that of the strip elements 34. The insulator 28 has a closed, annular shape and is wound around the outer circumference of the coil assembly 32. Specifically, the insulator 28 has a first end 28B facing in the first circumferential direction and a second end 28A facing in the second circumferential direction.The first and second ends 28B and 28A are arranged to overlap in the radial direction of the coil assembly 34 to form the insulator overlap portion 28C. A portion of the insulator 28 other than the insulator overlap portion 28C is hereinafter also referred to as the insulator main portion 28D. The insulator overlap portion 28C is located in one of the recesses 33 (see ). Fig. 4B) defined between the inner peripheral surface of the stator core 26 and the outer peripheral surfaces of the thin-walled portions 32B of the coil assembly 32.

[0156] As described above, the insulator overlap portion 28C is located in one of the recesses 33 defined between the stator core 26 and the thin-walled portions 32B of the coil assembly 32, thereby minimizing the risk that the insulator overlap portion 28C may cause radial misalignment of the coil assembly 32 with the stator core 26.

[0157] The total thickness F3, which results from the sum of a thickness of the insulator overlap portion 28C of the insulator 28 and a thickness of a corresponding thin-walled portion 32B of the coil assembly 32 in the radial direction of the coil assembly 32, is preferably selected to be equal to a thickness F1 of each thick-walled portion 32A of the coil assembly 32 in the radial direction of the coil assembly 32. Layers of the adhesive 70 (see Fig. 31) may be arranged on circumferentially opposite sides of the insulator overlap portion 28C of the insulator 28. TENTH AND ELEVENTH EXAMPLES

[0158] Electric motors according to the tenth and eleventh embodiments will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0159] The coil assembly 32 of the motor in the tenth embodiment as shown in Fig. 35, comprises a single strip element 34 and a plurality of coils 16 (see Fig. 9) formed on the strip element 34. The strip element 34 is wound multiple times in a plurality of turns. The insulator 28 is wound around the outer periphery of the coil assembly 32.

[0160] The thick-walled portion 32A of the coil assembly 32 and the insulator overlap portion 28C of the insulator 28 are spaced apart from each other at equal angular intervals in the circumferential direction of the coil assembly 32. The total thickness F3, which is the sum of the thickness of the insulator overlap portion 28C of the insulator 28 and the thickness of the thin-walled portion 32B of the coil assembly 32, is set to be equal to the thickness F4, which is the sum of the thickness of the insulator main portion 28D of the insulator 28 and the thickness of the thick-walled portion 32A of the coil assembly 32.

[0161] In the structure of this embodiment, as described above, the thick-walled portion 32A of the coil assembly 32 and the insulator overlap portion 28C of the insulator 28 are spaced apart from each other at equal angular intervals in the circumferential direction of the coil assembly 32. Moreover, as described above, the total thickness F3, which is the sum of the thickness of the insulator overlap portion 28C of the insulator 28 and the thickness of the thin-walled portion 32B of the coil assembly 32, is equal to the thickness F4, which is the sum of the thickness of the insulator main portion 28D of the insulator 28 and the thickness of the thick-walled portion 32A of the coil assembly 32.In other words, the insulator overlap portion 28C and the thin-walled portion 32B of the coil assembly 32 are arranged to overlap each other in the radial direction, thereby minimizing the misalignment of the coil assembly 32 with the stator core 26 in the radial direction due to the thick-walled portion 32A.

[0162] The insulator overlap section 28C may, as in the coil assembly 32 of the motor in the Fig. 36, be extended in the circumferential direction of the coil assembly 32. This allows the volume of the adhesive 70 (see Fig. 31) filled recess(es) 33 can be changed or regulated by means of the insulator overlap section 28C. TWELFTH EXAMPLE

[0163] An electric motor according to the twelfth embodiment will be described below. The same reference numerals used to describe the motor 10 in the first embodiment refer to the same or similar parts, and their detailed explanation will be omitted here.

[0164] The coil assembly 32 of the motor in this embodiment comprises, as shown in the Fig. 37 and Fig. 28 illustrates the coil-free portion 34J, which is a portion of the length of the third strip element 34 that is arranged closer in the first circumferential direction. The third strip element 34 is, as shown in Fig. 4B, is arranged closer to the stator core 26 than the first and second strip elements 34. No coil is formed on the coil-free portion 34J. The coil-free portion 34J is bent in a ring shape and extends in the circumferential direction. The coil-free portion 34J serves as an insulator 72. In other words, the insulator 72 forms a radially outer layer of the coil assembly 32.

[0165] The insulator 72 has portions that overlap in the radial direction of the coil assembly 32 and form the insulator overlap portion 72A. The insulator overlap portion 72A is in one of the recesses 33 (see Fig. 4B) formed between the inner peripheral surface of the stator core 26 and the outer peripheral surfaces of the thin-walled portions 32B of the coil assembly 32.

[0166] The above-described motor in this embodiment has the coil-free portion 34J of one of the strip elements 34, which plays a role in the same way as the insulator 28 of the motor in the tenth embodiment (see Fig. 35). This eliminates the need to manufacture the insulator 28 with an additional discrete element, thus minimizing the number of parts in the motor.

[0167] This disclosure is not limited to the above embodiment and modifications, but may be implemented by various embodiments without departing from the scope of the disclosure. This disclosure encompasses all possible combinations of the features of the above embodiment and modifications, or features similar to the parts of the above embodiment and modifications.

[0168] In each of the above embodiments, the coils 16 arranged on the strip elements 34 are connected to each other in a star connection, but may also be configured in a delta connection. The number of magnetic poles, phases, series-connected sets of coils 16, or parallel-connected sets of coils 16 of the motor in each of the above embodiments can be changed depending on the purpose. The motor in each of the embodiments can be used as an electric generator or can be configured as a brushless external rotor motor in which the rotor 12 is arranged radially outside the stator 14. The structure described in this disclosure can also be used with a rotor equipped with the coil assembly 32.

[0169] This disclosure is not limited to the above embodiments and modifications, but may be implemented by various embodiments without departing from the scope of the disclosure. This disclosure encompasses all possible combinations of the features of the above embodiments and modifications, or features similar to the parts of the above embodiments and modifications. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022-011872

[0001] JP 2017-070140

[0004]

Claims

[1] Coil assembly (32), with: a plurality of strip elements (34) made of an electrically insulating material, rolled in a circumferential direction of the coil assembly and stacked one on top of the other in a radial direction of the coil assembly, the strip elements having at least portions that overlap one another in the radial direction of the coil assembly; a plurality of coils (16) made of an electrically conductive material and formed on the strip elements, the coils being arranged in the circumferential direction; a thin-walled portion (32B) defined by a portion of the strip elements and having a first thickness in the radial direction; and a plurality of thick-walled portions (32A) defined by portions of the strip elements and having a second thickness in the radial direction that is greater than the first thickness, the thick-walled portions being spaced apart from each other in the circumferential direction. [2] Coil assembly according to claim 1, wherein the thick-walled sections are arranged apart from each other in a circumferential range of 0° to 180° as well as in a circumferential range of 180° to 360°, a first of the thick-walled sections has at least one section which is spaced at an angular interval of 180° from at least one section of a second of the thick-walled sections in the circumferential direction of the coil assembly, or at least a portion of one of the thick-walled portions is spaced at an angular interval of 180° from a region in which at least two of the thick-walled portions are arranged adjacent to one another in the circumferential direction of the coil assembly. [3] A coil assembly according to claim 1 or 2, wherein each of the strip elements has connecting means (43) extending therefrom and electrically connected to the coils, and the connecting means of the strip elements are arranged to coincide in the circumferential direction of the coil assembly. [4] A coil assembly according to claim 1 or 2, wherein each of the strip elements has a connecting means (43) extending therefrom and electrically connected to the coils, and the connecting means of the strip elements are arranged away from each other in the circumferential direction of the coil assembly. [5] A coil assembly according to claim 3 or 4, wherein the connecting means extending from the strip elements are arranged in one of the thick-walled sections. [6] A coil assembly according to claim 3 or 4, wherein the connecting means extending from the strip elements are arranged in the thin-walled portion. [7] Anchor (14), with: an armature core (26) made of a soft magnetic material in the form of a hollow cylinder; and a coil assembly according to any one of claims 1 to 6, wherein the coil assembly is arranged on either a radial inner peripheral surface or a radial outer peripheral surface of the armature core. [8] A coil assembly according to claim 7, further comprising an adhesive material disposed in a recess (33) defined between the armature core and the thin-walled portion to achieve adhesion between the armature core and the coil assembly. [9] A coil assembly according to claim 7 or 8, further comprising a flank (32C) formed at a boundary between the thin-walled portion and one of the thick-walled portions and located near the armature core, the flank having a height in the radial direction of the coil assembly. [10] A coil assembly according to any one of claims 7 to 9, further comprising an annular insulator (28) made of an electrically insulating material and having a length with a first end and a second end laid to overlap in the radial direction of the coil assembly, the insulator being mounted between the armature core and the coil assembly so that the first and second ends are disposed in a recess between the armature core and the thin-walled portion of the coil assembly. [11] A coil assembly according to any one of claims 7 to 9, wherein one of the strip elements closest to the armature core has a coil-free portion (34J) in which no coils are formed, the coil-free portion is curved and extends circumferentially of the coil assembly to serve as an insulator located near the armature coil, wherein the insulator has sections which are laid overlapping one another in the radial direction of the coil assembly and are arranged in a recess formed between the armature core and the thin-walled section of the coil assembly. [12] Anchor, with: an armature core made of a soft magnetic material in the form of a hollow cylinder; a coil assembly arranged on either a radial inner circumferential surface or a radial outer circumferential surface of the armature core and comprising a strip element, a plurality of coils, a thin-walled portion, and thick-walled portions, wherein the strip element is made of an electrically insulating material and is wound multiple times in a circumferential direction of the coil assembly, the coils are made of an electrically conductive material and are arranged in a circumferential direction of the coil assembly, the thin-walled portion being defined by a portion of the strip element and having a first thickness in a radial direction of the coil assembly, the thick-walled portions being defined by portions of the strip element and having a second thickness in the radial direction that is greater than the first thickness, and an annular insulator made of an electrically insulating material having a length with a first end and a second end overlapped in the radial direction of the coil assembly, the insulator being arranged between the armature core and the coil assembly such that the first and second ends are arranged in a recess formed between the armature core and the thin-walled portion of the coil assembly. [13] Rotating electric machine (10), with: a first, a stator (14) or a rotor (12) comprising an armature according to any one of claims 7 to 12; and a second one of the stator and the rotor, comprising magnets (18) arranged to oppose a coil assembly in a radial direction of the coil assembly.

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