JP7844178B2 - Motor coil board and motor - Google Patents

Description

The technology disclosed herein relates to a coil substrate, a motor coil substrate formed using the coil substrate, and a motor formed using the motor coil substrate.

Patent Document 1 discloses a coil substrate having a flexible substrate and spiral-shaped wiring formed on both sides of the flexible substrate. A motor coil substrate is formed by winding the coil substrate into a cylindrical shape. A motor is formed by placing the formed motor coil substrate inside a cylindrical yoke and arranging a rotating shaft and magnets inside the motor coil substrate.

Japanese Patent Publication No. 2020-89207

[Problems with Patent Document 1]
In the technology described in Patent Document 1, the coil substrate is considered to be wound circumferentially around an axis that extends perpendicular to the longitudinal direction (width direction), starting from one end of the flexible substrate in the longitudinal direction. The width of the portion of the wiring formed near one end of the flexible substrate in the longitudinal direction (i.e., the starting end in the winding direction) is considered to be wider than the width of the portion formed near the other end of the flexible substrate in the longitudinal direction (i.e., the ending end in the winding direction). In other words, when the coil substrate is wound circumferentially, the width of the wiring located on the outermost circumference is considered to be wider than the width of the wiring located on the inner circumference.

When a coil substrate is wound in the circumferential direction, the gaps between the wires are susceptible to force and bending because there are no wires in those gaps. In the technology described in Patent Document 1, the width of the outermost wire is wider than the width of the innermost wire. It is thought that the gaps between the outermost wires overlap with the gaps between the innermost wires. Therefore, it is conceivable that the motor coil substrate can be formed in a polygonal cylindrical shape with a polygonal cross-section rather than a cylindrical shape with a circular cross-section.

If the motor coil substrate is polygonal cylindrical, it may interfere with the magnets placed inside during motor assembly. Furthermore, an increase in the air gap between the motor coil substrate and the yoke may reduce heat dissipation. As a result, stable motor performance may not be achieved.

The coil substrate of the present invention comprises a flexible substrate having a first surface and a second surface opposite to the first surface, and a plurality of coils formed by wiring provided on the first surface and the second surface. The coil substrate can be formed into a cylindrical shape by winding it circumferentially around an axis extending in a direction perpendicular to the longitudinal direction, starting from a first end in the longitudinal direction of the flexible substrate. The flexible substrate has a first region near the first end and a second region adjacent to the first region. Of the wiring, the width of the first wiring formed in the first region is wider than the width of the second wiring formed in the second region.

In the coil substrate of the embodiment of the present invention, the width of the first wiring formed in the first region is wider than the width of the second wiring formed in the second region. When the coil substrate is wound in the circumferential direction, the second region is located in a layer further outward than the first region. The number of gaps between wirings in the outermost layer is greater than the number of gaps in the innermost layer. As a result, the overlap between the gaps between wirings located on the outermost periphery is reduced. When the coil substrate is wound in the circumferential direction, it is less likely to bend even if force is applied to the gaps between the wiring. When the coil substrate is wound in the circumferential direction, there are no wirings in the gaps between the wiring, so force is easily applied and it is prone to bending. Therefore, when the coil substrate of the embodiment is wound in the circumferential direction to form a motor coil substrate, the motor coil substrate can be formed in a cylindrical shape with a nearly circular cross-section. As a result, the occurrence of short circuits between wirings is suppressed. In addition, when forming a motor in which the motor coil substrate, magnets, and yoke are arranged inside the housing, interference between the magnets placed inside the motor coil substrate and the motor coil substrate is prevented. Furthermore, because the air gap between the motor coil substrate and the yoke remains constant, high heat dissipation is achieved. Therefore, when a motor is formed using the coil substrate of this embodiment, a motor with stable performance can be obtained.

The motor coil substrate of the present invention is formed by winding the above-described coil substrate of the present invention into a cylindrical shape. The coil substrate is wound around the axis, starting from the first end, with the first surface positioned on the inner side and the second surface on the outer side. The first wiring is arranged in the innermost first layer, and the second wiring is arranged in the second layer, which is outside the first layer.

As described above, the motor coil substrate of the embodiment of the present invention can be formed in a cylindrical shape with a substantially circular cross-section. Interference between the magnet and the motor coil substrate during motor formation is prevented. High heat dissipation is achieved. Therefore, when a motor is formed using the motor coil substrate of the embodiment, a motor with stable performance can be obtained.

The motor of the present invention is formed by arranging the above-described motor coil substrate inside a cylindrical yoke, and arranging a rotating shaft and magnets inside the motor coil substrate.

In the motor of this embodiment, interference between the magnet and the motor coil substrate is prevented. Furthermore, the air gap between the motor coil substrate and the yoke remains constant, resulting in high heat dissipation. A motor with stable performance is obtained.

A schematic plan view showing the coil substrate of the embodiment. A schematic bottom view showing the coil substrate of the embodiment. A schematic cross-sectional view showing the coil substrate of the embodiment. A schematic perspective view showing the motor coil board of the embodiment. A schematic cross-sectional diagram showing a portion of the motor coil substrate of the embodiment. A schematic cross-sectional view showing the motor of the embodiment. A schematic plan view showing the coil substrate of a modified example. A schematic cross-sectional view showing the coil substrate of a modified example. A schematic cross-sectional diagram showing a portion of the motor coil circuit board in a modified example.

[Embodiment]
Figure 1 is a plan view showing the coil substrate 2 of the embodiment. Figure 2 is a bottom view showing the coil substrate 2 of the embodiment. Figure 3 is a cross-sectional view of a part of the coil substrate 2. Figure 3 is a cross-sectional view between III-III in Figures 1 and 2. The coil substrate 2 of the embodiment has a flexible substrate 10 and a plurality of coils 20, 22, and 24.

The flexible substrate 10 is a resin substrate having a first surface 10F and a second surface 10B opposite to the first surface 10F. The flexible substrate 10 is formed using an insulating resin such as polyimide or polyamide. The flexible substrate 10 is flexible. The flexible substrate 10 is formed in a rectangular shape having four sides, from the first side E1 to the fourth side E4. The first side E1 is the short side at one end of the flexible substrate 10 in the longitudinal direction (arrow LD direction in Figure 1). The second side E2 is the short side at the other end in the longitudinal direction. Both the first side E1 and the second side E2 are short sides extending along the orthogonal direction (arrow OD direction in Figure 1) perpendicular to the longitudinal direction. Both the third side E3 and the fourth side E4 are long sides extending along the longitudinal direction. As will be explained in more detail later, when the coil substrate 2 is wound into a cylindrical shape to form the motor coil substrate 50 (see Figure 4), the first surface 10F is positioned on the inner circumference side, and the second surface 10B is positioned on the outer circumference side.

The flexible substrate 10 has a first region R1 near the first edge E1 and a second region R2 adjacent to the first region R1. The second region R2 extends from adjacent to the first region R1 to the vicinity of the second edge E2.

Coils 20, 22, and 24 are arranged along the longitudinal direction of the flexible substrate 10. Only three coils, 20, 22, and 24, are shown in Figure 1. The flexible substrate 10 may also contain other coils besides coils 20, 22, and 24, between coils 20 and 22, and between coils 22 and 24. Coil 20 is formed in the first region R1. The other coils (i.e., coils 22 and 24) are formed in the second region R2.

The coil 20 consists of a coil-shaped wiring 30F (Figure 1) provided on the first surface 10F and a coil-shaped wiring 30B (Figure 2) provided on the second surface 10B. Wirings 30F and 30B are formed in the first region R1 of the flexible substrate 10. Wirings 30F and 30B are electrically connected via via conductors 40 that penetrate the flexible substrate 10.

As shown in Figure 1, the wiring 30F is formed in a clockwise spiral shape (hexagonal spiral) from the outer circumference to the inner circumference. The via conductor 40 is formed at the inner circumference end of the wiring 30F. As shown in Figure 2, the wiring 30B is formed in a counterclockwise spiral shape (hexagonal spiral) from the inner circumference to the outer circumference. Both wiring 30F and 30B are formed for three turns (three rotations). Wiring 30F and wiring 30B are formed in the same spiral shape with the same winding direction when viewed from the same plane. Wiring 30F and wiring 30B function as a single coil 20 that is electrically connected in series.

As shown in Figure 3, the wiring 30F on the first surface 10F and the wiring 30B on the second surface 10B overlap when projected onto the first surface 10F with light perpendicular to the first surface 10F. That is, the wiring 30F and wiring 30B overlap in the thickness direction (vertical direction in the figure) via the flexible substrate 10.

Similarly, the coil 22 consists of wiring 32F (Figure 1) provided on the first surface 10F and wiring 32B (Figure 2) provided on the second surface 10B. Wirings 32F and 32B are formed in the second region R2 of the flexible substrate 10. Wirings 32F and 32B are electrically connected via via conductors 42.

Wiring 32F is formed in a clockwise spiral shape (hexagonal spiral) from the outer circumference to the inner circumference. The via conductor 42 is formed at the inner circumference end of wiring 32F. Wiring 32B is formed in a counter-clockwise spiral shape (hexagonal spiral) from the inner circumference to the inner circumference. Both wiring 32F and 32B are formed for 4 turns. Wiring 32F and wiring 32B are formed in the same spiral shape with the same winding direction when viewed from the same plane. Wiring 32F and wiring 32B function as a single coil 22 that is electrically connected in series.

As shown in Figure 3, wirings 32F and 32B overlap when projected onto the first surface 10F with light perpendicular to the surface. That is, wirings 32F and 32B overlap in the thickness direction (vertical direction in the figure) via the flexible substrate 10. The width W32 of wirings 32F and 32B is smaller than the width W30 of wirings 30F and 30B of coil 20. The spacing between wirings 32F and 32B is the same as the spacing between wirings 30F and 30B of coil 20.

Similarly, the coil 24 consists of wiring 34F (Figure 1) provided on the first surface 10F and wiring 34B (Figure 2) provided on the second surface 10B. Wirings 34F and 34B are formed in the second region R2 of the flexible substrate 10. Wirings 34F and 34B are electrically connected via via conductors 44.

Wiring 34F is formed in a clockwise spiral shape (hexagonal spiral) from the outer circumference to the inner circumference. The via conductor 44 is formed at the inner circumference end of wiring 34F. Wiring 34B is formed in a counter-clockwise spiral shape (hexagonal spiral) from the inner circumference to the outer circumference. Both wiring 34F and 34B consist of 5 turns. Wiring 34F and 34B are formed in the same spiral shape with the same winding direction when viewed from the same plane. Wiring 34F and 34B function as a single coil 24 electrically connected in series.

As shown in Figure 3, wirings 34F and 34B overlap when projected onto the first surface 10F with light perpendicular to the first surface 10F. That is, wirings 34F and 34B overlap in the thickness direction (vertical direction in the figure) via the flexible substrate 10. The width W34 of wirings 34F and 34B is smaller than the width W32 of wirings 32F and 32B of coil 22. That is, the width W34 of wirings 34F and 34B is smaller than the width W30 of wirings 30F and 30B of coil 20. The spacing between wirings 34F and 34B is the same as the spacing between wirings 32F and 32B of coil 22 (i.e., the spacing between wirings 30F and 30B of coil 20).

Although not shown in the diagram, the first surface 10F and the wiring 30F, 32F, 34F, etc. on the first surface 10F are covered with a resin insulating layer. Similarly, the second surface 10B and the wiring 30B, 32B, 34B, etc. on the second surface 10B are covered with a resin insulating layer.

Figure 4 is a schematic perspective view showing a motor coil substrate 50 using the coil substrate of the embodiment (Figures 1 to 3). As shown in Figure 4, the motor coil substrate 50 is formed by winding the coil substrate 2 of the embodiment (Figures 1 and 2) into a cylindrical shape. When the coil substrate 2 is wound into a cylindrical shape, it is wound multiple times in the circumferential direction around an axis extending orthogonally (an axis extending parallel to the first side E1), starting from the first side E1 (Figure 1). Furthermore, the number of times the coil substrate 2 is wound is not particularly limited. When the coil substrate 2 is wound into a cylindrical shape, the first surface 10F of the flexible substrate 10 is positioned on the inner circumference side, and the second surface 10B is positioned on the outer circumference side.

Figure 5 is a schematic cross-sectional diagram illustrating a portion of the motor coil substrate 50 shown in Figure 4. As shown in the figure, in the motor coil substrate 50, the first region R1 forms the innermost layer. The second region R2 forms a layer outside the innermost layer.

As described above, in the coil substrate 2 of this embodiment, the width W30 of the wirings 30F and 30B formed in the first region R1 is wider than the widths W32 and W34 of the wirings 32F, 32B, 34F, and 34B formed in the second region R2 (see Figure 3). The number of turns of the coils 22 and 24 formed by the wirings 32F, 32B, 34F, and 34B is greater than the number of turns of the coil 20 formed by the wirings 30F and 30B. Therefore, the number of gaps between wirings in the outermost layer is greater than the number of gaps in the inner layer (see Figure 5). As a result, the overlap between the gaps between wirings located on the outermost circumference is reduced compared to the gaps between wirings located on the inner circumference. When the coil substrate 2 is wound in the circumferential direction, it is less likely to bend even if force is applied to the gaps in the wiring. Therefore, when the coil substrate 2 of this embodiment is wound in the circumferential direction to form a motor coil substrate 50, the motor coil substrate 50 can be formed in a cylindrical shape with a nearly circular cross-section.

Figure 6 is a schematic cross-sectional view showing a motor 100 using the motor coil substrate 50 (Figures 4 and 5) of the embodiment. The motor 100 is formed by placing the motor coil substrate 50 inside the yoke 60, and arranging a rotating shaft 80 and a magnet 70 fixed to the rotating shaft 80 inside the motor coil substrate 50.

As described above, the configurations of the coil substrate 2 (Figures 1-3), motor coil substrate 50 (Figures 4 and 5), and motor 100 (Figure 6) of the embodiment have been explained. As described above, by using the coil substrate 2 of the embodiment, the motor coil substrate 50 can be formed in a cylindrical shape with a substantially circular cross-section. As a result, the occurrence of short circuits between wiring is suppressed. Furthermore, interference between the magnet 70, which is positioned inside the motor coil substrate 50, and the motor coil substrate 50 during the formation of the motor 100 is prevented. Also, since the air gap between the motor coil substrate 50 and the yoke 60 remains constant, high heat dissipation is achieved. Therefore, when the motor 100 is formed using the coil substrate 2 of the embodiment, a motor 100 with stable performance can be obtained.

Wiring 30F and 30B in the embodiment are examples of "first wiring." Wiring 32F, 32B, 34F, and 34B are examples of "second wiring." Coil 20 is an example of "first coil." Coils 22 and 24 are examples of "second coil."

[Another example of an embodiment]
In another embodiment, coils 20, 22, and 24 have the same number of turns.

[Examples of modifications to the embodiment]
Figures 7 to 9 show modified examples of the embodiment. In the modified examples, the arrangement of the wiring constituting coils 20, 22, and 24 differs from that of the embodiment. Figure 7 is a plan view showing the coil substrate 102 of the modified example. Figure 8 is a cross-sectional view of a part of the coil substrate 102. Figure 8 is a cross-sectional view between VIII and VIII in Figure 7.

As shown in Figures 7 and 8, the modified coil 20 is formed such that the wiring 30F constituting half a turn of one turn is formed on the first surface 10F side, and the wiring 30B constituting the remaining half turn is formed on the second surface 10B side, with adjacent turns staggered. The coil 20 comprises three turns of wiring 30F and 30B. The wiring 30F and 30B constituting each turn are electrically connected via via conductors 40 that penetrate the flexible substrate 10. Both the wiring 30F and 30B constituting the coil 20 are formed in the first region R1.

Similarly, coil 22 is formed by arranging the wiring 32F, which constitutes half a turn within one turn, on the first surface 10F side, and the wiring 32B, which constitutes the remaining half turn, on the second surface 10B side, with adjacent turns staggered. However, coil 22 comprises wiring 32F and 32B for four turns. The wiring 32F and 32B constituting each turn are electrically connected via via conductors 42. Wiring 32F and 32B are formed across the first region R1 and the second region R2.

As shown in Figure 8, the width W32 of wiring 32F and 32B is smaller than the width W30 of wiring 30F and 30B of coil 20. The spacing between wiring 32F and 32B is the same as the spacing between wiring 30F and 30B of coil 20.

The coil 24 is formed by arranging the wiring 34F, which constitutes half a turn of one coil, on the first surface 10F side, and the wiring 34B, which constitutes the remaining half turn, on the second surface 10B side, with adjacent turns being offset from each other. However, the coil 24 has wiring for five turns. The wiring 34F and 34B constituting each turn are electrically connected via via conductors 44. Wirings 34F and 34B are formed in the second region R2.

As shown in Figure 8, the width W34 of wiring 34F and 34B is smaller than the width W32 of wiring 32F and 32B of coil 22. That is, the width W34 of wiring 34F and 34B is smaller than the width W30 of wiring 30F and 30B of coil 20. The spacing between wiring 34F and 34B is the same as the spacing between wiring 32F and 32B of coil 22 (i.e., the spacing between wiring 30F and 30B of coil 20).

Although not shown in the diagram, the first surface 10F and the wiring 30F, 32F, and 34F are covered with a resin insulating layer. Similarly, the second surface 10B and the wiring 30B, 32B, and 34B are covered with a resin insulating layer.

In the modified example, the above-mentioned coil substrate 102 (Figures 7 and 8) is wound multiple times in the circumferential direction starting from the first side E1 to form the motor coil substrate 50 (see Figure 4). The number of windings of the coil substrate 102 is not particularly limited. In the motor coil substrate 50, the first surface 10F of the flexible substrate 10 is positioned on the inner circumference side, and the second surface 10B is positioned on the outer circumference side.

Figure 9 is a schematic cross-sectional diagram illustrating a portion of the modified motor coil substrate 50. As shown in Figure 9, in the modified motor coil substrate 50, the first region R1 forms the innermost layer. The second region R2 forms a layer outside the innermost layer.

As described above, in the coil substrate 2 of this embodiment, the width W30 of the wirings 30F and 30B formed in the first region R1 is wider than the widths W32, W34, etc. of the wirings 32F, 32B, 34F, and 34B formed in the second region R2 (see Figure 8). The number of turns of the coils 22 and 24 formed by the wirings 32F, 32B, 34F, and 34B is greater than the number of turns of the coil 20 formed by the wirings 30F and 30B. Therefore, the number of gaps between wirings in the outermost layer is greater than the number of gaps in the inner layer. As a result, the overlap between the gaps between wirings located on the outermost circumference is reduced compared to the gaps between wirings located on the inner circumference. When the coil substrate 2 is wound in the circumferential direction, it is less likely to bend even if force is applied to the gaps in the wiring. Therefore, when the coil substrate 2 of this embodiment is wound in the circumferential direction to form a motor coil substrate 50, the motor coil substrate 50 can be formed in a cylindrical shape with a nearly circular cross-section.

Wiring 30F and 30B in the embodiment are examples of "first wiring." Wiring 32F, 32B, 34F, and 34B are examples of "second wiring." Coil 20 is an example of "first coil." Coils 22 and 24 are examples of "second coil."

[Another example of modification]
In another example of the modification, the number of turns for coils 20, 22, and 24 are equal.

2, 102: Coil substrate 10: Flexible substrate 10F: First surface 10B: Second surface 20, 22, 24: Coils 30F, 32F, 34F: Wiring (on the first surface) 30B, 32B, 34B: Wiring (on the second surface) 40, 42, 44: Via conductor 50: Motor coil substrate 60: Yoke 70: Magnet 80: Rotating shaft 100: Motor E1: First side E2: Second side E3: Third side E4: Fourth side R1: First region R2: Second region

Claims (3)

A motor coil substrate is formed by winding multiple coil substrates around the flexible substrate, each of which can be formed into a cylindrical shape by winding around an axis extending in a direction perpendicular to the longitudinal direction, starting from a first end in the longitudinal direction of the flexible substrate, the flexible substrate having a first surface and a second surface opposite to the first surface, and wherein the coil substrate is formed by winding multiple coil substrates around the flexible substrate in a direction perpendicular to the longitudinal direction,
The flexible substrate has a first region near the first end and a second region adjacent to the first region.
Of the aforementioned wirings, the width of the first wiring formed in the first region is wider than the width of the second wiring formed in the second region.
The coil substrate is wound around the axis starting from the first end, with the first surface facing the inner side and the second surface facing the outer side, the first wiring is located in the innermost first layer, and the second wiring is located in the second layer which is outside the first layer. A motor coil substrate according to claim 1, wherein the plurality of coils include a first coil formed by the first wiring and a second coil formed by the second wiring, and the number of turns of the second coil is greater than the number of turns of the first coil. A motor formed by arranging the motor coil substrate according to claim 1 inside a cylindrical yoke, and arranging a rotating shaft and magnets inside the motor coil substrate.