Electric motor and method for manufacturing armature constituting said electric motor

Abstract

To provide an electric motor, which has a structure suitable for forming a magnetic path through which magnetic flux flows three-dimensionally and a method for manufacturing an armature constituting the electric motor.SOLUTION: An iron core 26 is configured to include a plurality of U-shaped members 28 and a plurality of U-shaped members 30 perpendicular to U-shaped members 28, and U-shaped members 28 and U-shaped members 30 each have a U-shape consisting of a pair of side parts that are parallel or approximately parallel to each other and an intermediate part connecting the pair of side parts, with the side parts forming the teeth part of the iron core 26 and the intermediate part forming the yoke part of the iron core 26.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an electric motor having a magnetic path in which magnetic flux flows three-dimensionally and a method for manufacturing an armature constituting the electric motor.

Background Art

[0002] An electric motor including an armature having an armature coil and an iron core, and a rotor facing the armature is known. In a conventional electric motor, magnetic flux flows planar, for example, along the moving direction, but an electric motor having a three-dimensional magnetic pole structure in which magnetic flux flows not only in the moving direction but also in a direction intersecting the moving direction has been proposed. For example, the electric motor described in Patent Document 1 is such an example. In the electric motor described in Patent Document 1, magnetic flux emerging from the open side surface of the magnetic pole block is configured to branch in the moving direction and in a direction intersecting the moving direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in an electric motor having a structure in which magnetic flux flows three-dimensionally (three-dimensional magnetic pole structure) as described in Patent Document 1, formation of a magnetic path for realizing this is required, but no suitable structure and manufacturing method have been proposed.

[0005] The present invention has been made in view of such circumstances, and its main object is to provide an electric motor having a structure suitable for forming a magnetic path in which magnetic flux flows three-dimensionally and a method for manufacturing an armature constituting the electric motor.

Means for Solving the Problems

[0006] In order to solve the above-described problems, a motor according to one aspect of the present invention includes a rotor including a core and an armature coil provided so as to surround the core, and a stator disposed to face the rotor. The core of the rotor is composed of a plurality of members made of electromagnetic steel sheets. Each of the plurality of members has a U shape including a pair of side portions parallel or substantially parallel to each other and an intermediate portion connecting the pair of side portions. The plurality of members include a plurality of first members and a plurality of second members whose longitudinal direction of the intermediate portion is perpendicular to the longitudinal direction of the intermediate portion of the first member. The intermediate portion of the first member and the intermediate portion of the second member respectively constitute the yoke portion of the core, and the side portion of the first member and the side portion of the second member respectively constitute the teeth portion of the core.

[0007] According to this configuration, by arranging the intermediate portion of the first member and the intermediate portion of the second member, which are formed in a U shape and constitute the core of the rotor, so as to face in directions perpendicular to each other, a magnetic path through which magnetic flux flows three-dimensionally can be easily realized.

[0008] Further, in the above aspect, the stator is configured to be rotatable about a rotation axis. In the plurality of first members, the intermediate portion is arranged along the rotation direction of the stator. In the plurality of second members, the intermediate portion is arranged along the rotation axis. According to this configuration, a magnetic path through which magnetic flux flows in the rotation direction and the rotation axis direction can be easily realized.

[0009] Further, in the above aspect, the plurality of second members are arranged at the center in the direction of the rotation axis in the rotor, and the plurality of first members are arranged on both sides of the second member in the direction of the rotation axis in the rotor. According to this configuration, a magnetic path with the shortest magnetic flux path can be formed.

[0010] Further, the plurality of members made of the electromagnetic steel sheets each have an insulating coating on their surfaces. According to this configuration, losses due to the generation of eddy currents can be effectively reduced.

[0011] Also, in the above aspect, the electromagnetic steel sheet is composed of a wire rod. According to this configuration, a U-shaped member can be easily formed by bending the wire rod.

[0012] Also, in the above aspect, each of the plurality of second members is arranged such that the pair of side portions of the second members adjacent to each other overlap in the direction of the rotation axis, and the intermediate portions of the second members adjacent to each other overlap in the radial direction centered on the rotation axis. The second member having the pair of side portions located at both ends in the direction of the rotation axis is bent at least in the rotation direction with respect to the pair of side portions at the intermediate portion. According to this configuration, the intermediate portions of the second members are arranged to overlap in the radial direction, so that the core is likely to increase in size in the radial direction. On the other hand, in the second member portion where at least a pair of side portions are located at both ends in the direction of the rotation axis, the intermediate portion is bent in the rotation direction with respect to the pair of side portions, so that the increase in the size of the core in the radial direction can be reduced.

[0013] Also, in the above aspect, a holding member made of resin is provided that holds the entire yoke portion formed by the intermediate portions of the plurality of members from the outside in the radial direction. According to this configuration, the deformation of the core can be suppressed by the holding member when the motor is driven. Further, since the holding member is made of resin, an increase in weight due to the provision of the holding member can also be reduced.

[0014] Also, in the above aspect, the holding member has insertion holes into which the side portions of the plurality of members are inserted from the outside in the radial direction. According to this configuration, at the time of assembly, the side portions of the plurality of members can be inserted into the insertion holes formed in the holding member, so that the core can be easily configured.

[0015] In a method for manufacturing an armature that constitutes an electric motor according to one aspect of the present invention, the method includes a first step of molding each of the plurality of first members and the plurality of second members, a second step of molding a plurality of blocks in which the plurality of first members and the plurality of second members are fixed in a prescribed number respectively, and a third step of connecting the plurality of blocks to each other to mold the holding member. According to this method for manufacturing an armature, by molding a plurality of blocks in which a prescribed number of first members and second members are fixed, and connecting the plurality of blocks to each other to mold the holding member, an armature composed of the plurality of first members and the plurality of second members can be easily manufactured.

[0016] In a method for manufacturing an armature that constitutes an electric motor according to another aspect of the present invention, the method includes a first step of molding each of the plurality of first members and the plurality of second members, and a second step of inserting each of the side portions of the plurality of first members and each of the side portions of the plurality of second members into the insertion holes of the holding member. According to this configuration, by inserting each of the side portions of the plurality of first members and each of the side portions of the plurality of second members into the insertion holes formed in the holding member, an armature composed of the plurality of first members and the plurality of second members can be easily manufactured.

Advantages of the Invention

[0017] The electric motor according to the present invention can easily realize a magnetic path in which magnetic flux flows three-dimensionally. Further, according to the method for manufacturing an armature that constitutes the electric motor according to the present invention, an armature that realizes a magnetic path in which magnetic flux flows three-dimensionally can be easily manufactured.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

DETAILED DESCRIPTION OF THE INVENTION

[0019] [Overall Structure of the Electric Motor] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view for explaining the outline of an electric motor 10 according to an embodiment of the present invention. FIG. 2 is an enlarged view of a part in the rotation direction of the electric motor 10 in FIG. 1.

[0020] The electric motor 10 includes a rotor 12 (also referred to as a rotating element or a rotor), and a stator 14 (also referred to as a stationary element or a stator) disposed on the outer peripheral side of the rotor 12. The electric motor 10 of the present embodiment is a radial gap type electric motor in which the rotor 12 is rotatably disposed inside the stator 14. The rotor 12 and the stator 14 are disposed to face each other in the radial direction, and a radial gap (gap) is formed between the rotor 12 and the stator 14.

[0021] The rotor 12 is formed in an annular shape and is configured to be rotatable about the rotation axis CL of a rotation axis (output axis), not shown, that rotates together with the rotor 12.

[0022] The rotor 12 includes a plurality of magnetic pole blocks 16 having magnetism, and a back yoke 18. Each of the plurality of magnetic pole blocks 16 includes a core 20 (rotor core) disposed to face the stator 14, and a plurality of permanent magnets 22A to 22C that surround the core 20 with the facing surface to the stator 14 open.

[0023] The plurality of permanent magnets 22A to 22C that constitute the magnetic pole block 16 are disposed with the same magnetic poles facing the core 20. Also, adjacent magnetic pole blocks 16 are connected with one surface of the permanent magnets 22A to 22C in contact with each other. The back yoke 18 is an annular member and is formed of, for example, a soft magnetic material. A plurality of magnetic pole blocks 16 are disposed on the outer periphery of the back yoke 18 so as to be adjacent in the rotation direction (circumferential direction).

[0024] The stator 14 is formed in an annular shape as a whole and is fixed non-rotatably, such as being connected to a case, not shown. The stator 14 includes a plurality of stator coils 24 and a core 26 (stator core).

[0025] The plurality of armature coils 24 each have a frame shape with a frame hole 25 (see FIG. 12) formed inside. Further, the armature coil 24 has a rectangular parallelepiped outer shape, and the longitudinal side is arranged along the rotation axis line CL direction (hereinafter, the axial direction). Further, the plurality of armature coils 24 are arranged side by side in the rotation direction and are arranged in series in the axial direction.

[0026] The iron core 26 is formed in a U shape and includes a plurality of U-shaped members 28 and a plurality of U-shaped members 30A to 30C (hereinafter, when not distinguished, the U-shaped member 30). Specifically, each of the plurality of U-shaped members 28 is composed of a pair of side portions 42 parallel (or substantially parallel) to each other and an intermediate portion 44 connecting the pair of side portions 42 (see FIG. 4). Further, each of the plurality of U-shaped members 30A to 30C is composed of a pair of side portions 46A to 46C (when not distinguished, the side portion 46) parallel (or substantially parallel) to each other and intermediate portions 48A to 48C (when not distinguished, the intermediate portion 48) connecting the pair of side portions 46A to 46C (see FIG. 5). The U-shaped members 28 and 30 are each formed from a wire rod 32 (see FIG. 8) made of electromagnetic steel sheet. Note that the U-shaped member 28 corresponds to the "first member" in the present invention, and the U-shaped members 30A to 30C correspond to the "second member" in the present invention.

[0027] The U-shaped member 30 is arranged in a posture perpendicular to the U-shaped member 28. That is, the longitudinal direction of the intermediate portion 44 of the U-shaped member 28 is perpendicular to the longitudinal direction of the intermediate portions 48A to 48C of the U-shaped members 30A to 30C.

[0028] A pair of side portions 42 of each U-shaped member 28 are inserted into the frame hole 25 formed in each armature coil 24 so as to straddle the armature coils 24 adjacent to each other in the rotation direction. Further, a pair of side portions 46A to 46C of each U-shaped member 30 are inserted into the frame hole 25 formed in each armature coil 24 so as to straddle the armature coils 24 arranged in series (two rows) in the axial direction.

[0029] FIG. 3 is a view in which the upper part of FIG. 2 is enlarged and the armature coil 24 is removed. FIG. 4 is a view seen from the direction along the rotation axis of FIG. 3, and FIG. 5 is a view seen in the rotation direction of FIG. 3. The arrows shown in FIGS. 3 to 5 indicate the flow of magnetic flux when the armature coil 24 (omitted in FIGS. 3 to 5) is energized.

[0030] As shown in FIGS. 3 to 5, in the plurality of U-shaped members 28, the intermediate portions 44 are arranged along the rotation direction of the armature 14. Each of the U-shaped members 28 is arranged at equal angular intervals in the rotation direction and is arranged so as to be stacked in the axial direction.

[0031] In the plurality of U-shaped members 30A to 30C, the intermediate portions 48A to 48C are arranged along the rotation axis CL. In each of the plurality of U-shaped members 30A to 30C, a pair of side portions 46A to 46C overlap with a pair of side portions 46A to 46C of adjacent U-shaped members 30A to 30C in the axial direction, and the intermediate portions 48A to 48C overlap with the intermediate portions 48A to 48C of adjacent U-shaped members 30A to 30C in the radial direction centered on the rotation axis CL.

[0032] Specifically, in the U-shaped member 30A, a pair of side portions 46A are arranged on the innermost side in the axial direction, and the intermediate portion 48A is arranged on the innermost side in the radial direction. The U-shaped member 30B is arranged such that a pair of side portions 46B overlap with a pair of side portions 46A of the U-shaped member 30A on the outer side in the axial direction, and the intermediate portion 48B overlaps with the intermediate portion 48A of the U-shaped member 30A on the outer side in the radial direction. The U-shaped member 30C is arranged such that a pair of side portions 46C overlap with a pair of side portions 46B of the U-shaped member 30B on the outer side in the axial direction, and the intermediate portion 48C overlaps with the intermediate portion 48B of the U-shaped member 30B on the outer side in the radial direction. That is, among the plurality of U-shaped members 30A to 30C, the U-shaped member 30C has a pair of side portions 46C arranged on the outermost side in the axial direction and an intermediate portion 48C arranged on the outermost side in the radial direction.

[0033] In the assembled state, the side portions 42, 46A to 46C of each U-shaped member 28, 30 face the mover 12 at their tips and are surrounded by the armature coil 24. These side portions 42, 46 constitute the teeth portions surrounded by the armature coil 24 in the iron core 26 (stator core). Further, the intermediate portions 44, 48A to 48C of the U-shaped members 28, 30 constitute the yoke portions that connect the pair of side portions 42, 46A to 46C in the iron core 26 (stator core).

[0034] When the armature coil 24 of the armature 14 configured as described above is energized, a magnetic path through which magnetic flux flows three-dimensionally is formed. That is, as shown by the arrows in FIGS. 3 to 5, the magnetic flux flows in and out in the radial direction through the teeth portions (side portions 42, 46A to 46C) of each U-shaped member 28, 30. Further, the magnetic flux that has moved in the radial direction branches and flows along the axial direction along the intermediate portion 48 (yoke portion) of the U-shaped member 30 in addition to one and the other of the rotational directions along the intermediate portion 44 (yoke portion) of the U-shaped member 28. Thereby, a magnetic path through which magnetic flux flows three-dimensionally is formed.

[0035] Here, a shorter magnetic flux path requires less total amount of the wire material 32. Further, since the loss when the magnetic flux changes with time depends on the volume of the iron core 26 through which the magnetic flux passes, a shorter path can reduce the loss. From these, it is desirable that the magnetic flux paths are connected by the shortest route. Therefore, in the iron core 26 of the armature 14, a U-shaped member 30 stacked in the direction in which the magnetic flux flows in the axial direction is arranged at the center in the axial direction, and U-shaped members 28 stacked in the direction in which the magnetic flux flows in the rotational direction are arranged on both sides of the U-shaped member 30 in the axial direction of the armature 14, respectively. Further, with respect to the U-shaped member 30, the magnetic flux path is shortened by adopting a nested structure in which three U-shaped members 30A to 30C having different sizes are arranged so as to overlap without gaps.

[0036] Further, the cross-sections of the U-shaped members 28 and 30 are formed in a quadrangular (angular) shape. By forming the cross-sections of the U-shaped members 28 and 30 in a quadrangular shape, in a state where the U-shaped members 28 and 30 are laminated, the teeth portion and the yoke portion can be formed densely. That is, the cross-sectional areas of the teeth portion and the yoke portion through which magnetic flux passes in the U-shaped members 28 and 30 can be maximized.

[0037] Also, the surfaces of the U-shaped members 28 and 30 are each coated with an insulating film. By coating the surfaces of the U-shaped members 28 and 30 with an insulating film, conduction between adjacent U-shaped members 28 and 30 is prevented. When conduction occurs between adjacent U-shaped members 28 and 30, eddy currents are generated, increasing losses. Even when conduction occurs between adjacent U-shaped members 28 and 30, compared to the case where the entire iron core is composed of a single iron block, the generation of eddy currents can be reduced by the contact resistance. Further, in order to sufficiently reduce the losses due to the generation of eddy currents, it is preferable to insulate and coat the surfaces of the U-shaped members 28 and 30 respectively. By sufficiently reducing the losses due to the generation of eddy currents, the motor 10 can be suitably used for high-speed drive applications.

[0038] Also, as shown in FIG. 5 and the like, since the intermediate portions 48A to 48C (yoke portions) of the U-shaped members 30A to 30C are arranged to be laminated in the radial direction, there is a risk that the armature 14 may increase in size in the radial direction due to the intermediate portions 48A to 48C protruding in the radial direction. In contrast, as shown in FIGS. 6 and 7, in the U-shaped member 30, the intermediate portion 48C of the U-shaped member 30C in which a pair of side portions 46C (teeth portions) are located at both ends in the axial direction is bent in the rotational direction with respect to the pair of side portions 46C, thereby avoiding the protrusion of the intermediate portion 48C in the radial direction.

[0039] The U-shaped member 30C-1 on the left side of FIG. 6 shows the shape before bending, and the U-shaped member 30C-2 on the right side shows the shape after bending. As shown in FIG. 6, in the U-shaped member 30C-2 on the right side, the intermediate portion 48C is bent at approximately a right angle (90 degrees) with respect to the pair of side portions 46C forming the teeth portion.

[0040] FIG. 7 shows a state where a U-shaped member 30C-2 with an intermediate portion 48C bent with respect to a pair of side portions 46C (tooth portions) is assembled to the armature 14. Note that FIG. 7 also shows a U-shaped member 30C-1 in which the intermediate portion 48C is not bent with respect to the pair of side portions 46C. In the U-shaped member 30C-2 shown in FIG. 7, the intermediate portion 48C is bent in the rotational direction with respect to the pair of side portions 46C (tooth portions), so that the intermediate portion 48C (yoke portion) is located radially inward compared to the intermediate portion 48C of the U-shaped member 30C-1. As a result, the protrusion of the intermediate portion 48C in the radial direction is eliminated, and an increase in the size of the armature 14 in the radial direction is avoided.

[0041] Note that in the U-shaped member 30C-2 of FIG. 7, the intermediate portion 48C is bent at a substantially right angle (90 degrees) with respect to the side portion 46C (tooth portion). However, within a range where interference with adjacent U-shaped members 28 and 30 can be avoided after assembly, the bending angle can be freely adjusted within the range of 0 degrees to 90 degrees. Also, not only the U-shaped member 30C but also the U-shaped members 30A and 30B may be appropriately bent so as to further avoid an increase in the size of the armature 14 in the radial direction.

[0042] [Manufacturing method of U-shaped member] Generally, the size of an electric motor is changed according to its application. However, it is not easy from the viewpoint of mass productivity to manufacture dedicated parts for each electric motor with a different size. Also, since the size of the manufacturable electric motor depends on the size of the manufacturing apparatus, in the case of a large electric motor exceeding the manufacturing apparatus, it is desirable to manufacture the core by dividing it and then assembling it. That is, in manufacturing the core 26 of the present embodiment, a plurality of U-shaped members 28 and 30 are manufactured, and by assembling these U-shaped members 28 and 30, a core 26 of an arbitrary size can be manufactured.

[0043] The manufacturing method of the U-shaped members 28 and 30 will be described below. FIG. 8 is a diagram showing the manufacturing method of the U-shaped members 28 and 30. The U-shaped members 28 and 30 are both formed from a common wire 32. By bending the wire 32 at the bending position A on the left in FIG. 8 and cutting the extra portions indicated by the broken lines, an L-shaped member 35A shown in the upper right of FIG. 8 is formed. Also, by bending the wire 32 at the bending position B on the left in FIG. 8 and cutting the extra portions indicated by the broken lines, an L-shaped member 35B shown in the lower right of FIG. 8 is formed. Next, by joining the ends of the pair of L-shaped members 35A in a state where they are in contact with each other, a U-shaped member having a predetermined dimension is formed. Similarly, by joining the ends of the pair of L-shaped members 35B in a state where they are in contact with each other, a U-shaped member having a dimension different from that in the upper right of FIG. 8 is formed. In this way, since the U-shaped member is composed of a pair of L-shaped members, it becomes possible to manufacture a U-shaped member with a large dimension.

[0044] As described above, by adjusting the bending position of the wire 32, a U-shaped member with an arbitrary dimension can be formed from the common wire 32. For example, the U-shaped member 28, the U-shaped members 30A, 30B, and 30C in the present embodiment each have different dimensions. In contrast, by adjusting the bending position of the wire 32 and forming L-shaped members with different dimensions, these U-shaped members 28 and 30 can be formed from the common wire 32.

[0045] Also, since there is a concern that the magnetoresistance will increase if a gap is formed at the joint of the pair of L-shaped members, a structure is desirable in which there is no gap at the joint, the strength is ensured even after joining, and for example, displacement in the shear direction can be prevented. In contrast, a stepped shape or a concavo-convex shape is formed at the ends of the L-shaped members adjacent to each other in the stacking direction, and a stepped shape or a concavo-convex shape is also formed at the ends of the L-shaped members joined to these. When joining the L-shaped members to each other to form a U-shaped member, a structure that ensures the strength of the joint by fitting the stepped shape or the concavo-convex shape formed in each may be used.

[0046] Fig. 9(a) shows a mode in which a stepped shape 34 is formed by two L-shaped members 35X and 35Y adjacent to each other in the stacking direction, and Fig. 9(b) shows a state in which the L-shaped members 35X and 35Y in Fig. 9(a) are joined.

[0047] As shown on the left side of Fig. 9(a), the stepped shape 34 is formed by the overlapping of two L-shaped members 35X and 35Y with different lengths. Similarly, on the right side of Fig. 9(a) as well, the stepped shape 34 is formed by the overlapping of two L-shaped members 35X and 35Y with different lengths. Note that the L-shaped member 35X and the L-shaped member 35Y with different dimensions are arranged to be joined. When the L-shaped members 35X and 35Y facing each other in the left-right direction are joined to each other from the state shown in Fig. 9(a), the state shown in Fig. 9(b) is obtained. At this time, the stepped shapes 34 formed on both the left and right sides fit together with each other, and since each joint portion is adjacent to the L-shaped members 35X and 35Y, the joint portion is less likely to shift in the shear direction.

[0048] Fig. 10(a) shows a mode in which a concavo-convex shape 36 is formed by three or more L-shaped members 35X and 35Y adjacent to each other in the stacking direction, and Fig. 10(b) shows a state in which the L-shaped members 35X and 35Y in Fig. 10(a) are joined.

[0049] As shown on the left side of Fig. 10(a), the concavo-convex shape 36 is formed by the alternating overlapping of three or more L-shaped members 35X and 35Y with different lengths in the stacking direction. Similarly, on the right side of Fig. 10(a) as well, the concavo-convex shape 36 is formed by the alternating overlapping of three or more L-shaped members 35X and 35Y with different lengths in the stacking direction. The concavo-convex shapes 36 facing each other in Fig. 10(a) are formed such that the concave portion and the convex portion are opposite to each other. That is, the L-shaped member 35X and the L-shaped member 35Y are arranged to be joined. When the opposing L-shaped members 35X and 35Y are joined to each other from the state shown in Fig. 10(a), the state shown in Fig. 10(b) is obtained. At this time, the concavo-convex shapes 36 formed on both the left and right sides fit together with each other, and since each joint portion is adjacent to the L-shaped members 35X and 35Y, the joint portion is less likely to shift in the shear direction.

[0050] [Method for Fixing the Core] Next, the fixing method of the U-shaped members 28 and 30 will be described. The core 26 of the armature 14 is composed of a combination of a plurality of U-shaped members 28 and 30, and a structure for holding them is required. Further, in the motor 10 of the present embodiment, since the magnetic flux flows in two directions, the rotational direction and the axial direction, the cross-sectional area in each direction becomes small, and as a result, the intermediate portions 44 and 48 (yoke portions) of the U-shaped members 28 and 30 become thin. Therefore, a structure for suppressing the deformation of the core 26 of the armature 14 due to the electromagnetic force generated during the drive of the motor 10 is desirable. To cope with these, the entire intermediate portion (the entire yoke portion) of each U-shaped member 28 and 30 is held from the radially outer side by a holding member 40 described later, thereby fixing the entire core 26 of the armature 14.

[0051] FIG. 11 is a view showing a mode in which the holding member 40 is used as an aspect of the fixing structure for fixing the U-shaped members 28 and 30, and is a view of a part of the rotational direction of the motor 10 viewed in the axial direction of the rotation axis. As shown in FIG. 11, each intermediate portion 44, 48 (yoke portion) of each U-shaped member 28, 30 is covered by a holding member 40 formed in an annular shape, and the entire yoke portion is held by the holding member 40. Thereby, each U-shaped member 28, 30 is held by the holding member 40, and the deformation of the core 26 is also suppressed by the holding member 40.

[0052] The holding member 40 is preferably formed of resin. Resin has the characteristics of being insulating and lightweight. Since the holding member 40 is located at a position close to the armature coil 24 through which current flows during the drive of the motor 10, there is a risk of contact with the armature coil 24. On the other hand, since the holding member 40 is formed of an insulating resin, it is not affected even when the holding member 40 comes into contact with the armature coil 24. Further, by forming the holding member 40 of a lightweight resin, an increase in the weight of the motor 10 can be suppressed.

[0053] Incidentally, insulating paper 45 is interposed between the armature coil 24 and the side portions 42, 46 (tooth portions) of the U-shaped members 28, 30 to prevent energization between the armature coil 24 and the U-shaped members 28, 30. Fig. 12(a) shows the state immediately before the side portions 42, 46 of the pair of U-shaped members 28, 30 adjacent to the frame holes 25 of the armature coil 24 are inserted, and Fig. 12(b) shows the state in which the side portions 42, 46 of the pair of U-shaped members 28, 30 are inserted into the frame holes 25 of the armature coil 24. As shown in Fig. 12(a), insulating paper 45 is pre-inserted into the frame holes 25 of the armature coil 24, and from this state, the side portions 42, 46 of the U-shaped members 28, 30 are inserted into the frame holes 25.

[0054] Here, when each of the U-shaped members 28, 30 is fixed by the holding member 40, as shown in Fig. 12, the holding member 40 is positioned on the side of the intermediate portions 44, 48 (yoke portions) of the U-shaped members 28, 30 that is close to the armature coil 24. If this holding member 40 interferes with the insulating paper 45, there is a risk that the space between the armature coil 24 and the side portions 42, 46 of the U-shaped members 28, 30 cannot be properly insulated by the insulating paper 45. When the insulation becomes insufficient, if leakage current occurs in the armature coil 24, the current related to the magnetic interaction decreases because the current does not pass through the assumed path, resulting in a decrease in the electromagnetic force and also having an adverse effect on other devices.

[0055] To prevent this, a holding member 40 that covers the U-shaped members 28, 30 has a space 49 (notch) into which the insulating paper 45 is inserted formed at a portion facing the side portions 42, 46 of the U-shaped members 28, 30. The space 49 is formed at the connecting portion between the side portion (tooth portion) and the intermediate portion (yoke portion) of the U-shaped members 28, 30. By forming this space 49, when the side portions 42, 46 are inserted into the frame holes 25 of the armature coil 24, the end portion of the insulating paper 45 is inserted into the space 49 as shown in Fig. 12(b). Thereby, the space between the U-shaped members 28, 30 and the armature coil 24 is properly insulated by the insulating paper 45.

[0056] [Manufacturing method of armature] Next, a method for manufacturing the armature 14 will be described. The holding member 40 is composed of a plurality of blocks, and these blocks are assembled to form it. Each block has a function of fixing a prescribed number of U-shaped members 28 and 30 in a bundled state in advance. For example, a plurality of U-shaped members 28 surrounded by the dashed line in FIG. 3 are blocked and fixed to one block. Also, U-shaped members 30A to 30C surrounded by the chain double-dashed line in FIG. 3 are blocked and fixed to one block.

[0057] FIG. 13 shows an aspect of the block 50 forming the holding member 40 and illustrates the fixing structure of a plurality of U-shaped members 28. FIG. 13(a) shows a top view of the block 50, and FIG. 13(b) shows a side view of the block 50. In FIG. 13, the portion of the U-shaped member 28 accommodated within the block 50 is indicated by a dashed line. As shown in FIG. 13, with a plurality of U-shaped members 28 bundled, the intermediate portion 44 of the U-shaped member 28 is fixed so as to be covered by the block 50. Also, a plurality of U-shaped members 28 adjacent to each other in the rotational direction after assembly are similarly fixed by the block 50.

[0058] Each block 50 is formed with an engaging protrusion 52 and an engaging hole 54 that engage with an adjacent block 50 after assembly. The engaging protrusion 52 is located on one side in the rotational direction, while the engaging hole 54 is formed so as to be located on the other side in the rotational direction. During assembly, the adjacent blocks 50 are connected to each other by engaging the engaging protrusion 52 and the engaging hole 54 of the adjacent blocks 50 with each other. The engaging protrusion 52 and the engaging hole 54 are not limited to the shapes shown in FIG. 13 and may be appropriately changed as long as they can engage with each other.

[0059] Similarly, the U-shaped members 30A to 30C are also fixed by blocks in a bundled state. The blocks are formed with engaging protrusions or engaging holes that are connected to the adjacent blocks 50 in the axial direction. During assembly, the U-shaped members 30A to 30C are fixed by engaging the engaging protrusions or engaging holes with the engaging holes or engaging protrusions (not shown) formed in the axial direction of the adjacent blocks 50 in the axial direction, so that the blocks fixing the U-shaped members 30A to 30C are connected to the blocks 50. As a result, each adjacent block in the rotational direction and the axial direction is connected to each other, and after the blocks are assembled, a holding member 40 that holds the plurality of U-shaped members 28 and 30 from the radially outer side is formed. That is, a core 26 in which the plurality of U-shaped members 28 and 30 are held by the holding member 40 is formed.

[0060] Alternatively, instead of the holding member 40 composed of the plurality of blocks, each U-shaped member 28, 30 can be fixed using a holding member 60 formed using a 3D printer.

[0061] FIG. 14 is a diagram for explaining a fixing structure of the U-shaped members 28, 30 using the holding member 60. FIG. 14(a) shows an assembling step of inserting the U-shaped member 28 into the holding member 60, FIG. 14(b) shows a state where the U-shaped member 28 is inserted into the holding member 60, and FIG. 14(c) shows a state where the U-shaped member 30 is assembled in addition to the U-shaped member 28.

[0062] The holding member 60 has, for example, an annular shape made of resin. The holding member 60 is formed with a plurality of insertion holes 62 into which the side portions 42, 46 of the plurality of U-shaped members 28, 30 are respectively inserted. During assembly, after the side portions 42, 46 of each U-shaped member 28, 30 are inserted into the respectively defined insertion holes 62, the U-shaped members 28, 30 are adhered to the holding member 60 using an adhesive or the like. As a result, the states shown in FIGS. 14(b) and 14(c) are obtained, and each U-shaped member 28, 30 is fixed to the holding member 60. Note that the holding member 60 may be composed of not only one member but also a combination of a plurality of blocks.

[0063] FIG. 15 is a flowchart for explaining the manufacturing process flow of the armature 14 composed of U-shaped members 28 and 30. The flowchart of FIG. 15 corresponds to the embodiment using the holding member 40 described above.

[0064] In the first basic step of FIG. 15, the wire 32 is bent at a predetermined position and the excess portion is cut to form a plurality of L-shaped members having a desired dimension. In the second basic step, the L-shaped members formed in the first basic step are joined to form a plurality of U-shaped members 28 and 30 having a desired dimension. In the blocking step, a plurality of blocks 50 fixed in a bundled state by a predetermined number out of the plurality of U-shaped members 28 are formed, and a plurality of blocks fixed in a bundled state by a predetermined number out of the plurality of U-shaped members 30A to 30C are formed. In the assembling step, the formed plurality of blocks are connected to each other to form one holding member 40. At this time, the engaging portions (engaging protrusions 52 and engaging holes 54) formed on adjacent blocks are engaged with each other, so that the adjacent blocks are integrally connected. Note that the second basic step corresponds to the "first step" in the present invention, the blocking step corresponds to the "second step" in the present invention, and the assembling step corresponds to the "third step" in the present invention.

[0065] FIG. 16 is a flowchart for explaining the manufacturing process flow of the armature 14 when the holding member 60 is used instead of the holding member 40. In the first basic step of FIG. 16, the wire 32 is bent at a predetermined position and the excess portion is cut to form a plurality of L-shaped members having a desired dimension. In the second basic step, the L-shaped members formed in the first basic step are joined to form a plurality of U-shaped members 28 and 30 having a desired dimension. In the assembling step, after the side portions 42 and 46 of the U-shaped members 28 and 30 formed in the second basic step are inserted into the insertion holes 62 formed in the holding member 60 formed by a 3D printer from the radially outer side, the U-shaped members 28 and 30 are fixed to the holding member 60 using an adhesive or the like. Note that the second basic step corresponds to the "first step" in the present invention, and the assembling step corresponds to the "second step" in the present invention.

[0066] [Function, etc.] As described above, by forming the core 26 from a plurality of U-shaped members 28 and 30, arranging the middle portion 44 of the U-shaped member 28 along the rotation direction, and arranging the middle portion 48 of the U-shaped member 30 along the rotation axis CL, a magnetic path through which magnetic flux flows three-dimensionally can be easily formed. Further, by fixing the U-shaped members 28 and 30 with the holding member 40, the armature 14 (core 26) composed of the plurality of U-shaped members 28 and 30 can be easily manufactured. Alternatively, by using a holding member 60 having insertion holes 62 into which the side portions 42 and 46 of the U-shaped members 28 and 30 are inserted, the armature 14 (core 26) composed of the plurality of U-shaped members 28 and 30 can also be easily manufactured.

[0067] [Modification Example] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and may be appropriately modified without departing from the gist of the invention. For example, in the above embodiment, the U-shaped members 28 and 30 are formed by connecting a pair of L-shaped members 35 to each other. However, for example, when the motor 10 is small, it may be formed into a U-shape by bending two portions of a single wire 32.

[0068] In the above embodiment, among the U-shaped members 30A to 30C whose middle portions are overlapped in the radial direction, only the U-shaped member 30C located most radially outside is bent, but the U-shaped members 30A and 30B may also be bent.

[0069] In the above embodiment, two armature coils 24 are arranged in series in the axial direction, but are not necessarily limited to two. That is, three or more armature coils 24 may be arranged in series in the axial direction.

[0070] In the above embodiment, the surfaces of the U-shaped members 28 and 30 are insulated, but it may be carried out without applying the above insulation coating. For example, the cross-sectional areas of the U-shaped members 28 and 30 may be made circular, and the contact areas between adjacent U-shaped members 28 and 30 may be minimized to reduce losses.

[0071] In the above-described embodiment, the engaging protrusion 52 and the engaging hole 54 are formed in the block for fixing the plurality of U-shaped members 28 and 30, and the adjacent blocks are connected by engaging the engaging protrusion 52 and the engaging hole 54 of the adjacent blocks with each other. However, the connection method of the blocks is not limited to this. For example, screw holes may be formed in each block, and the adjacent blocks may be connected by screwing them. Alternatively, an engaging portion for engaging a clip may be set in each block, and the blocks may be connected by clips installed so as to straddle the adjacent blocks. Alternatively, the adjacent blocks may be connected by an adhesive or welding or the like.

[0072] In the above-described embodiment, after inserting the plurality of U-shaped members 28 and 30 into the insertion holes 62 of the holding member 60, they are fixed by adhesion with an adhesive or the like. However, it is not necessarily limited to an adhesive. For example, the U-shaped members 28 and 30 may be fixed by press-fitting them into the insertion holes 62.

Description of Reference Numerals

[0073] 10: Electric motor 12: Rotor 14: Stator 24: Stator coil 26: Core 28: U-shaped member (first member, member) 30: U-shaped member (second member, member) 40: Holding member 42: Side portion 44: Intermediate portion 46: Side portion 48: Intermediate portion 60: Holding member 62: Insertion hole

Claims

1. An armature comprising a core and an armature coil provided so as to surround the core, and a rotor disposed opposite to the armature, the electric motor comprising: the core of the armature is composed of a plurality of members made of electromagnetic steel sheets; each of the plurality of members has a U-shape composed of a pair of side portions parallel or substantially parallel to each other and an intermediate portion connecting the pair of side portions; the plurality of members are configured to include a plurality of first members and a plurality of second members whose longitudinal direction of the intermediate portion is perpendicular to the longitudinal direction of the intermediate portion of the first members; the intermediate portion of the first member and the intermediate portion of the second member respectively constitute the yoke portion of the core; the side portion of the first member and the side portion of the second member respectively constitute the teeth portion of the core, characterized in that it is an electric motor.

2. the rotor is configured to be rotatable about a rotation axis; in the plurality of first members, the intermediate portion is arranged along the rotation direction of the rotor; in the plurality of second members, the intermediate portion is arranged along the rotation axis, characterized in that it is the electric motor according to claim 1.

3. the plurality of second members are arranged in the center in the direction of the rotation axis in the armature; in the plurality of first members, they are respectively arranged on both sides of the second member in the direction of the rotation axis in the armature, characterized in that it is the electric motor according to claim 2.

4. the plurality of members made of electromagnetic steel sheets each have their surfaces insulated and coated, characterized in that it is the electric motor according to any one of claims 1 to 3.

5. the electromagnetic steel sheet is composed of a wire rod, characterized in that it is the electric motor according to any one of claims 1 to 3.

6. in each of the plurality of second members, the pair of side portions overlap with the pair of side portions of the adjacent second member in the direction of the rotation axis, and the intermediate portion overlaps with the intermediate portion of the adjacent second member in the radial direction centered on the rotation axis; in the second member where the pair of side portions are located at both ends in the direction of the rotation axis, at least the intermediate portion is bent in the rotation direction with respect to the pair of side portions, characterized in that it is the electric motor according to any one of claims 2 or 3.

7. The electric motor according to any one of claims 1 to 3, characterized in that it comprises a holding member made of resin that holds the entire yoke portion formed by the intermediate portions of the plurality of members from the radially outer side.

8. The electric motor according to claim 7, characterized in that the holding member has insertion holes into which the side portions of the plurality of members are respectively inserted from the radially outer side.

9. A method for manufacturing the armature constituting the electric motor according to claim 7, a first step of molding the plurality of first members and the plurality of second members respectively; a second step of molding a plurality of blocks in which the plurality of first members and the plurality of second members are respectively fixed in a predetermined number; a third step of connecting the plurality of blocks to each other to mold the holding member, characterized in that it includes a method for manufacturing an armature.

10. A method for manufacturing the armature constituting the electric motor according to claim 8, a first step of molding the plurality of first members and the plurality of second members respectively; a second step of inserting the side portions of each of the plurality of first members and the side portions of each of the plurality of second members into the insertion holes of the holding member respectively, characterized in that it includes a method for manufacturing an armature.

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