Axial gap motor

Abstract

To provide an axial gap motor in which an installation area of a coil is ensured while avoiding interference with a position sensor.SOLUTION: An axial gap motor includes: a yoke rotatably supported; a magnetic pole portion fixed to the yoke and magnetized to have polarities alternately different in a circumferential direction around a rotation axis of the yoke; a plurality of first coils facing the magnetic pole portion in a direction of the rotation axis and arranged in the circumferential direction; a plurality of second coils facing the magnetic pole portion in a direction of the rotation axis and arranged in the circumferential direction; and a position sensor surrounded by any of the plurality of first coils and configured to detect a rotational position of the yoke.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an axial gap motor.

Background Art

[0002] An axial gap motor including a plurality of coils and a position sensor for detecting the rotational position of a yoke is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to avoid interference with the position sensor, a plurality of coils are installed at positions away from the position sensor. For this reason, the installation area of the coils decreases, and it becomes difficult to provide many coils at appropriate positions, which may deteriorate the characteristics of the motor.

[0005] Therefore, an object of the present invention is to provide an axial gap motor in which the installation area of coils is ensured while avoiding interference with a position sensor.

Means for Solving the Problems

[0006] The above object can be achieved by an axial gap motor including a rotatably supported yoke, a magnetic pole portion fixed to the yoke and magnetized with alternately different polarities in the circumferential direction around the rotation axis of the yoke, a plurality of first coils facing the magnetic pole portion in the direction of the rotation axis and arranged in the circumferential direction, a plurality of second coils facing the magnetic pole portion in the direction of the rotation axis and arranged in the circumferential direction, and a position sensor surrounded by any one of the plurality of first coils and detecting the rotational position of the yoke. [Advantages of the Invention]

[0007] An axial gap motor can be provided in which the installation area of the coil is ensured while avoiding interference with the position sensor. [Brief Description of the Drawings]

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0009] [Schematic Configuration of Axial Gap Motor] Figure 1 is a front view of the axial gap motor 1. Figure 2 is a sectional view taken along line A-A of Figure 1. Figure 2 schematically shows the axial gap motor 1, with some components omitted. The axial gap motor 1 includes a support shaft 10, a yoke 20, magnetic pole portions 30 and 40, and a coil unit S. The support shaft 10 rotatably supports the yoke 20. The support shaft 10 includes a flange portion 11, a stepped portion 12, and a thin shaft portion 13. The stepped portion 12 has a smaller diameter than the flange portion 11. The thin shaft portion 13 has a smaller diameter than the stepped portion 12. Two bearings B are held on the thin shaft portion 13. The yoke 20 includes a cylindrical portion 22, and flange portions 23 and 24. The flange portions 23 and 24 are each flange-shaped. The flange portions 23 and 24 are separated from each other in the axial direction A. The coil unit S includes a printed circuit board 50 and a reinforcing plate 60. The reinforcing plate 60 is omitted in Figure 2. The coil unit S is disposed between the flange portions 23 and 24.

[0010] The magnetic pole portion 30 is provided on the surface of the flange portion 23 facing the coil unit S. The magnetic pole portion 40 is provided on the surface of the flange portion 24 facing the coil unit S. Each of the magnetic pole portions 30 and 40 is an annular permanent magnet. The surfaces of the magnetic pole portions 30 and 40 facing the coil unit S are magnetized with different polarities alternately in the circumferential direction. In this embodiment, each of the magnetic pole portions 30 and 40 has eight pole numbers in the circumferential direction. Note that each of the magnetic pole portions 30 and 40 may be a plurality of permanent magnets arranged in the circumferential direction. Also in this case, the surfaces of these plurality of permanent magnets facing the coil unit S are magnetized with different polarities alternately in the circumferential direction. The magnetic pole portions 30 and 40 correspond to the first and second magnetic pole portions.

[0011] The printed circuit board 50 is provided with a plurality of coils, which will be described in detail later. These coils face the magnetic pole portions 30 and 40 in the axial direction A with a gap therebetween. By controlling the energization states of these coils, the yoke 20 rotates with respect to the support shaft 10 according to the magnetic forces generated between the coils and the magnetic pole portion 30 and between the coils and the magnetic pole portion 40. Incidentally, the outer peripheral end portion of the coil unit S is held by a holder (not shown), and the coil unit S is non-rotatable relative to the yoke 20.

[0012] FIG. 3 is a front view of the coil unit S. FIG. 4 is a rear view of the coil unit S. FIG. 5 is a front view of the coil unit S with the reinforcing plate 60 removed therefrom. FIG. 6 is a front view of the coil unit S with the reinforcing plate 60, the frames 70 and 80 removed therefrom. Each of the printed circuit board 50 and the reinforcing plate 60 is circular in shape. An opening 51 and 61 for passing the support shaft 10 are formed at the center of each of the printed circuit board 50 and the reinforcing plate 60.

[0013] As shown in FIG. 6, the printed circuit board 50 has the U-phase coils U1 to U4, the V-phase coils V1 to V4, and the W-phase coils W1 to W4 assembled thereto. The coils U1 to U4 are configured by distributed windings. The same applies to the coils V1 to V4 and W1 to W4. The coils U1 to U4, V1 to V4, and W1 to W4 are electrically connected to the printed circuit board. The coils U1, V1, W1, U2, V2, W2, U3, V3, W3, U4, V4, and W4 are arranged in the circumferential direction C (counterclockwise in FIG. 6). The coils U1 to U4 are set at intervals of 90 degrees in the circumferential direction C. The coils V1 to V4 are set at intervals of 90 degrees in the circumferential direction C. The coils W1 to W4 are set at intervals of 90 degrees in the circumferential direction C.

[0014] As shown in FIG. 6, coils U1, W1, V2, U3, W3, and V4 are installed on the same surface of the printed circuit board 50 at 60-degree intervals in the circumferential direction C, corresponding to a plurality of first coils. Coils V1, U2, W2, V3, U4, and W4 are embedded in the printed circuit board 50 at 60-degree intervals in the circumferential direction C, corresponding to a plurality of second coils. The number of coils installed on the printed circuit board 50 and the number of coils embedded in the printed circuit board 50 are both six.

[0015] As shown in FIG. 6, coil U1 is axially spaced from coils W4 and V1 and partially overlaps in the axial direction A. Coil W1 is axially spaced from coils V1 and U2 and partially overlaps in the axial direction A. Coil V2 is axially spaced from coils U2 and W2 and partially overlaps in the axial direction A. Coil U3 is axially spaced from coils W2 and V3 and partially overlaps in the axial direction A. Coil W3 is axially spaced from coils V3 and U4 and partially overlaps in the axial direction A. Coil V4 is axially spaced from coils U4 and W4 and partially overlaps in the axial direction A. Coil V1 is axially spaced from coils U1 and W1 and partially overlaps in the axial direction A. Coil U2 is axially spaced from coils W1 and V2 and partially overlaps in the axial direction A. Coil W2 is axially spaced from coils V2 and U3 and partially overlaps in the axial direction A. Coil V3 is axially spaced from coils U3 and W3 and partially overlaps in the axial direction A. Coil U4 is axially spaced from coils W3 and V4 and partially overlaps in the axial direction A. Coil W4 is axially spaced from coils V4 and U1 and partially overlaps in the axial direction A. Thereby, the axial gap motor 1 is suppressed from increasing in size in the axial direction A.

[0016] As shown in Fig. 3, coils U1, W1, V2, U3, W3, and V4 are each fitted into holes 63 of reinforcing plate 60. Thereby, the outer peripheries of coils U1, W1, V2, U3, W3, and V4 are reinforced. Notches 64 and 65 for allowing the lead wires from each coil to escape are continuously formed in hole 63. Reinforcing plate 60 is an example of a reinforcing member. Incidentally, instead of reinforcing plate 60, the peripheries of the outer sides of coils U1, W1, V2, U3, W3, and V4 on printed circuit board 50 may be sealed with resin.

[0017] As shown in Figs. 4 to 6, each of coils V1, U2, W2, V3, U4, and W4 is embedded so as to be fitted into hole 53 of printed circuit board 50. Therefore, the strength of these coils is ensured.

[0018] As shown in Figs. 3 and 5, each of coils U1, W1, V2, U3, W3, and V4 is wound around a frame 70. As shown in Fig. 4, each of coils V1, U2, W2, V3, U4, and W4 is wound around a frame 80. Thereby, the strength of these coils is ensured. Two positioning holes 71 are formed in frame 70. Positioning holes 71 are used for positioning when installing frame 70 around which the coil is wound onto printed circuit board 50. Similarly, two positioning holes 81 are formed in frame 80. Positioning holes 81 are used for positioning when fitting frame 80 around which the coil is wound into hole 53 of printed circuit board 50.

[0019] As shown in Fig. 6, the shapes of coils U1 to U4, V1 to V4, and W1 to W4 are all the same. Therefore, the operation of winding the coils around frame 70 or 80 is the same, and the operation is easy. Also, handling of these coils during assembly is easy. Specifically, a jig with a rod-shaped positioning component (not shown) is inserted into positioning hole 71 or positioning hole 81, and frame 70 or frame 80 around which the coil is wound is positioned at a predetermined position on printed circuit board 50 and fixed to printed circuit board 50 by adhesion or the like.

[0020] As shown in FIGS. 3 and 5, a notch 72 is formed in the frame body 70. The position sensors P1, P2, and P3 are respectively surrounded by the coils W1, V2, and U3. Specifically, the position sensor P1 is located within the notch 72 of the frame body 70 around which the coil W1 is wound. The position sensor P2 is located within the notch 72 of the frame body 70 around which the coil V2 is wound. The position sensor P3 is located within the notch 72 of the frame body 70 around which the coil U3 is wound. In this way, interference between the position sensors P1 to P3 and the coils W1, V2, and U3 is avoided respectively. As a result, the installation areas of the coils U1 to U4, V1 to V4, and W1 to W4 are ensured. Incidentally, each of the position sensors P1 to P3 is a Hall element.

[0021] As shown in FIG. 6, the position sensor P1 is installed between the coils V1 and U2 adjacent to each other in the circumferential direction C. The position sensor P2 is installed between the coils U2 and W2 adjacent to each other in the circumferential direction C. The position sensor P3 is installed between the coils W2 and V3 adjacent to each other in the circumferential direction C. In this way, the dead space on the printed circuit board 50 is effectively utilized.

[0022] FIG. 7 is a cross-sectional view taken along line B-B of FIG. 3. The position sensor P3 surrounded by the coil U3 does not protrude from the end face of the reinforcing plate 60. Thereby, thinning in the axial direction A of the coil unit S is ensured. Also, for example, it is possible to avoid an operator touching the position sensor P3 when handling the coil unit S. The same applies to the position sensors P1 and P2.

[0023] As described above, the coils U1 to U4, V1 to V4, and W1 to W4 constitute a three-phase coil. The total number of these coils is 12, which is an even number. Also, the number of poles of each of the magnetic pole portions 30 and 40 is 8. In this way, the total number of coils is 1.5 times the number of poles.

[0024] As another example, the total number of coils may be 6, which is an even number, and the number of poles of the magnetic pole portion may be 4. In this case, the number of coils in each of the U phase, V phase, and W phase is 2. For example, three coils may be installed on the printed circuit board, and the remaining three coils may be embedded in the printed circuit board. Also in this case, the total number of coils is 1.5 times the number of poles.

[0025] As yet another example, the total number of coils may be 18, which is an even number, and the number of poles of the magnetic pole portion may be 6. In this case, the number of coils in each of the U phase, V phase, and W phase is 6. For example, nine coils may be installed on the printed circuit board, and the remaining nine coils may be embedded in the printed circuit board. In this case, the total number of coils is three times the number of poles.

[0026] As in the above-described examples, when the coils are wound in a distributed winding, a position sensor is surrounded by any one of the coils, and the position sensor is arranged between another two coils that are spaced apart from the coil in the axial direction A and adjacent to each other in the circumferential direction C, three-phase coils are configured as in the above examples, and it is preferable that the total number of coils is an even number and is 1.5 times or three times the number of poles. Thereby, it becomes possible to arrange the coil and the position sensor at theoretical positions without interference. Furthermore, 1.5 times the number of poles is preferable. This is because when the number of poles increases as in the case of three times the number of poles, the number of required coils increases, and the configuration becomes more complicated, making manufacturing difficult.

[0027] In the yoke 20 of the axial gap motor 1 of the present embodiment, the magnetic pole portions 30 and 40 are provided, but only one of the magnetic pole portions 30 and 40 may be provided.

[0028] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0029] 1 Axial gap motor 20 Yoke 30 and 40 magnetic pole parts (first magnetic pole part, second magnetic pole part) Coils U1, W1, V2, U3, W3, V4 (multiple first coils) Coils V1, U2, W2, V3, U4, W4 (multiple second coils) S coil unit 50 printed circuit board 60 reinforcing plate

Claims

1. A yoke rotatably supported; A magnetic pole portion fixed to the yoke and magnetized with alternately different polarities in the circumferential direction centered on the rotation axis of the yoke; A plurality of first coils facing the magnetic pole portion in the direction of the rotation axis and arranged in the circumferential direction; A plurality of second coils facing the magnetic pole portion in the direction of the rotation axis and arranged in the circumferential direction; An axial gap motor comprising a position sensor surrounded by any one of the plurality of first coils and detecting the rotational position of the yoke.

2. Any one of the plurality of first coils partially overlaps in the direction of the rotation axis with two of the second coils adjacent to each other in the circumferential direction; The axial gap motor according to claim 1, wherein any one of the plurality of second coils partially overlaps in the direction of the rotation axis with two of the first coils adjacent to each other in the circumferential direction.

3. Comprising a printed circuit board electrically connected to the plurality of first coils, the plurality of second coils, and the position sensor; The plurality of first coils and the position sensor are arranged on the printed circuit board; The axial gap motor according to claim 2, wherein the plurality of second coils are embedded in the printed circuit board.

4. The axial gap motor according to claim 3, wherein the position sensor is arranged between two of the second coils adjacent to each other in the circumferential direction.

5. Each of the plurality of first coils and the plurality of second coils is wound in a distributed winding; The plurality of first coils and the plurality of second coils constitute a three-phase coil; The total number of the plurality of first coils and the plurality of second coils is an even number and is 1.5 times or 3 times the number of poles of the magnetic pole portion. The axial gap motor according to any one of claims 1 to 4.

6. Comprising a first coil frame around which any one of the plurality of first coils is wound; The axial gap motor according to any one of claims 1 to 4, wherein the first coil frame has a notch for allowing the position sensor to pass through.

7. Comprising a second coil frame around which any one of the plurality of second coils is wound; The second coil wound around the second coil frame is embedded in the printed circuit board together with the second coil frame. The axial gap motor according to any one of claims 1 to 4.

8. The magnetic pole portion includes first and second magnetic pole portions spaced apart from each other in the direction of the rotation axis. The plurality of first coils and the plurality of second coils are disposed between the first and second magnetic pole portions, the axial gap motor according to any one of claims 1 to 4.

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