JP2023176208A - Axial gap motor and robot - Google Patents

Abstract

To provide an axial gap motor with high flatness accuracy of a rotor and low eddy current loss in a yoke, and a robot including the axial gap motor.SOLUTION: An axial gap motor includes a rotor having a magnet and a yoke and rotating around a rotating axis and a stator, the yoke has a first divided yoke and a second divided yoke adjacent to the first divided yoke in a circumferential direction centered on a rotation axis, the first divided yoke and the second divided yoke respectively include a first laminated body and a second laminated body, the first laminated body includes a plurality of first steel plates having a first length in the circumferential direction, which are stacked in a radial direction around the rotation axis, the second laminated body includes a plurality of second steel plates having a second length in the circumferential direction longer than the first length, which are stacked in the radial direction, and the first divided yoke and the second divided yoke have different ratios of the length of the first laminated body and the length of the second laminated body in the radial direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to an axial gap motor and a robot.

Patent Document 1 discloses an axial gap type rotating electrical machine in which a rotor and a stator are disposed opposite to each other with an air gap interposed in a direction parallel to the axis of a rotor shaft. This rotor includes a rotor yoke including an amorphous spiral laminate formed by spirally stacking amorphous magnetic metal ribbons, and a magnet disposed on a surface of the rotor yoke facing the stator. Since the amorphous magnetic metal ribbon has a higher resistivity than the magnetic steel sheet, it contributes to reducing eddy current loss in the rotor yoke.

Japanese Patent Application Publication No. 2011-139600

Amorphous spiral laminates are manufactured by spirally winding amorphous magnetic metal ribbons. For this reason, it is difficult to sufficiently improve the flatness accuracy of the surface on which the magnet is arranged. If the flatness accuracy of the surface on which the magnet is arranged is low, the amount of air gap will vary. In this case, the amount of air gap cannot be made sufficiently small, and there is a concern that the torque of the rotating electrical machine may decrease or vibrations may occur.

The axial gap motor according to the application example of the present invention is
a rotor having a magnet and a yoke in which the magnet is arranged, and rotating around a rotation axis;
a stator disposed apart from the rotor;
Equipped with
The yoke includes a first divided yoke and a second divided yoke adjacent to the first divided yoke in a circumferential direction centered on the rotation axis,
The first divided yoke and the second divided yoke each include a first laminate and a second laminate,
The first laminate includes a plurality of first steel plates that are stacked in a radial direction around the rotation axis and have a first length in the circumferential direction,
The second laminate is disposed outside the first laminate in the radial direction, and is laminated in the radial direction, and has a second length in the circumferential direction that is longer than the first length. including a plurality of second steel plates,
The first divided yoke and the second divided yoke are characterized in that the ratio of the length of the first stacked body to the length of the second stacked body in the radial direction is different from each other.

The robot according to the application example of the present invention is
It is characterized by comprising an axial gap motor according to an application example of the present invention.

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an axial gap motor according to a first embodiment. FIG. 2 is a plan view of the first rotor shown in FIG. 1. FIG. FIG. 3 is a partial cross-sectional view of the first rotor cut along a curved surface parallel to the circumferential direction. FIG. 2 is a plan view of a yoke included in the first rotor shown in FIG. 1; 5 is a partially enlarged view of FIG. 4. FIG. It is a graph obtained by calculating the relationship between the stacked layer thickness ratio (h11/H1) and the area ratio of the yoke. As a first reference example, it is a diagram showing a model in which a first divided yoke and a second divided yoke are each constructed of two laminates having different lengths in the circumferential direction. 8 is a graph obtained by calculating the relationship between the lower stage height ratio (h71A/H3) and the area ratio of the yoke for the model shown in FIG. 7. As a second reference example, it is a diagram showing a model in which the first divided yoke and the second divided yoke are composed of three laminates each having a different length in the circumferential direction. 10 is a graph obtained by calculating the relationship between the lower height ratio (h71B/H4), the middle height ratio (h72B/H4), and the area ratio of the yoke for the model shown in FIG. 9. FIG. 7 is a partial plan view of a yoke included in a first rotor of an axial gap motor according to a first modification. It is a partial sectional view showing the 1st rotor of the axial gap motor concerning the 2nd modification. It is a partial plan view which shows the 1st rotor of the axial gap motor based on the 3rd modification. FIG. 3 is a perspective view showing a robot according to a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The axial gap motor and robot of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

1. First Embodiment First, an axial gap motor according to a first embodiment will be described.

FIG. 1 is a vertical cross-sectional view showing a schematic configuration of an axial gap motor according to a first embodiment. In each of the following figures, three mutually orthogonal axes are represented by arrows, and are referred to as an X axis, a Y axis, and a Z axis. Both directions along the X axis are referred to as "X directions," both directions along the Y axis are referred to as "Y directions," and both directions along the Z axis are referred to as "Z directions." Further, the direction of the arrow is defined as a + direction, and the direction opposite to the + direction is defined as a - direction. Note that the +Z direction is sometimes referred to as "above" or "upper", and the -Z direction is sometimes referred to as "down" or "lower", and viewing from the +Z direction is also referred to as planar view. Further, the radial direction centered on the rotation axis AX is R, and the circumferential direction centered on the rotation axis AX is T. Further, in the radial direction R, the side moving away from the rotation axis AX is defined as the "outside", and the side approaching the rotation axis AX is defined as the "inside".

The axial gap motor 1 shown in FIG. 1 is a two-rotor, one-stator type motor. Specifically, the axial gap motor 1 shown in FIG. 1 includes a shaft 2 that rotates around a rotation axis AX parallel to the Z-axis, and a first rotor that is fixed to the shaft 2 and rotates together with the shaft 2 around the rotation axis AX. 3 and a second rotor 4, a stator 5 disposed between the first rotor 3 and the second rotor 4 along the rotation axis AX, and a motor case 6. The first rotor 3 and the second rotor 4 each have a disk shape, and the shaft 2 is fixed at the center thereof. Such an axial gap motor 1 rotates the first rotor 3, the second rotor 4, and the shaft 2 about the rotation axis AX, and transmits rotational force to a driven member connected to the shaft 2.

The shaft 2 is a solid member having a substantially cylindrical shape. A first rotor 3 and a second rotor 4 are fixed to the shaft 2 concentrically. However, the shaft 2 may be hollow. In that case, the wiring may be passed inside the shaft 2.

The motor case 6 has a first case 61, a second case 62, and a side case 63. The first case 61 and the second case 62 each have an annular shape, and the shaft 2 is inserted through the center thereof. The side case 63 has a cylindrical shape and connects the outer edge of the first case 61 and the outer edge of the second case 62.

The first rotor 3 and the second rotor 4 are housed in a motor case 6. The first rotor 3 includes a rotor frame 32, a yoke 34, and a magnet 39. The second rotor 4 includes a rotor frame 42, a yoke 44, and a magnet 49.

A stator 5 is arranged between the first rotor 3 and the second rotor 4. The stator 5 is fixed to the motor case 6 and is separated from the first rotor 3 via an air gap 11 and separated from the second rotor 4 via an air gap 12. The stator 5 has an annular shape, and the shaft 2 is inserted through the center thereof.

Each part of the axial gap motor 1 will be described in further detail below.
1.1. Stator The stator 5 shown in FIG. 1 includes a stator core 52 and a coil 54 wound around the stator core 52.

The stator core 52 includes a plurality of teeth portions 53 whose number corresponds to the number of phases and the number of poles of the axial gap motor 1. The teeth portions 53 are arranged at equal intervals along the circumferential direction T. The coil 54 is wound around each tooth portion 53. The coil 54 may be a conducting wire directly wound around the teeth 53, or may be a conducting wire wound around a bobbin or the like in advance and attached to the teeth 53.

The axial gap motor 1 has an energizing circuit (not shown), and each coil 54 is connected to this energizing circuit. When each coil 54 is energized, a magnetic field is generated from the stator core 52, and rotational torque is generated in the first rotor 3 and the second rotor 4. Thereby, the shaft 2 rotates around the rotation axis AX.

The stator core 52 is made of various magnetic materials, such as a laminate of electromagnetic steel sheets or amorphous alloy foil, a green compact of magnetic powder, or a hybrid body of a combination of electromagnetic steel sheets or amorphous alloy foil and magnetic powder.

Note that the stator core 52 may be a single component or an assembly of multiple components.

1.2. First Rotor The rotor frame 32 of the first rotor 3 has a disk shape, and as shown in FIG. 1, has a through hole 322 and a recess 324 that opens upward.

The through hole 322 penetrates the rotor frame 32 along the rotation axis AX. The shaft 2 is fixed to the through hole 322 by, for example, press fitting. The recess 324 has an annular shape and accommodates the yoke 34 and the magnet 39.

Examples of the constituent material of the rotor frame 32 include metal materials such as carbon steel, cast iron, stainless steel, aluminum alloy, magnesium alloy, and titanium alloy, ceramic materials such as alumina and zirconia, and resin materials such as engineering plastics. Examples include various fiber-reinforced plastics such as CFRP (Carbon Fiber Reinforced Plastics) and GFRP (Glass Fiber Reinforced Plastics), fiber-reinforced composite materials such as FRC (Fiber Reinforced Ceramics), and FRM (Fiber Reinforced Metallics).

Moreover, it is preferable that the constituent material of the rotor frame 32 is a non-magnetic material. This makes it difficult for eddy current loss to occur in the rotor frame 32 due to changes in magnetic flux. As a result, it is possible to suppress the temperature rise of the first rotor 3 and suppress the deterioration of the performance of the axial gap motor 1. Note that the nonmagnetic material refers to a material whose relative magnetic permeability is 3.0 or less.

FIG. 2 is a plan view of the first rotor 3 shown in FIG. 1.
As shown in FIG. 2, the recess 324 is provided at the outer edge of the rotor frame 32 and has an annular shape centered on the rotation axis AX in plan view. A yoke 34 and a plurality of magnets 39, which are not shown in FIG. 2, are housed in the recess 324. The yoke 34 and the magnets 39 are fixed to the rotor frame 32 using adhesive or the like, for example. Moreover, the yoke 34 and the magnet 39 and the spaces between the magnets 39 may also be bonded with adhesive or the like. Further, an adhesive or mold resin may be provided to cover the magnet 39.

FIG. 3 is a partial cross-sectional view of the first rotor 3 taken along a curved surface parallel to the circumferential direction T.
The plurality of magnets 39 are arranged along the circumferential direction T and have an annular shape as a whole. Two magnets 39 adjacent to each other in the circumferential direction T are arranged so that their magnetization directions are opposite to each other along the Z-axis.

The yoke 34 is arranged below the magnet 39. That is, when the surface of the yoke 34 shown in FIG. 3 facing the stator 5 is defined as the "opposing surface 342", the magnets 39 are arranged on the opposing surface 342.

FIG. 4 is a plan view of the yoke 34 that the first rotor 3 shown in FIG. 1 has. Further, FIG. 5 is a partially enlarged view of FIG. 4.

Further, the yoke 34 shown in FIG. 4 is composed of a plurality of parts. Specifically, the 12 first divided yokes 35 and the 12 second divided yokes 36 are arranged so that the center line 350 of each first divided yoke 35 and the center line 360 of each second divided yoke 36 are in the radial direction. The yoke 34 has an annular shape as a whole by arranging the yoke 34 alternately along the circumferential direction T so as to be along the circumferential direction. Note that the number of first divided yokes 35 and second divided yokes 36 is not limited to this, and may be less than or greater than 12.

The first divided yoke 35 and the second divided yoke 36 have different shapes in plan view. By alternately arranging the first divided yokes 35 and the second divided yokes 36 that have different shapes in plan view, the yoke 34 having an annular shape as a whole is constructed while suppressing the gap 33 that occurs between them. Ru. Hereinafter, the difference in plan view shape will be explained.

The first divided yoke 35 shown in FIG. 4 includes a first stacked body 371 and a second stacked body 372.
The first stacked body 371 includes a plurality of first steel plates 375 stacked in the radial direction R, as shown in FIG. 4 . At this time, the plurality of first steel plates 375 are stacked so that the center line of the first steel plates 375 is along the radial direction R. In FIG. 5, the length of the first steel plate 375 in the circumferential direction T is defined as "first length s11." Here, the length of the first steel plate 375 in the circumferential direction T refers to the length of the first steel plate 375 in a direction perpendicular to the center line 350 within a plane seen when the first divided yoke 35 is viewed from above.

The second stacked body 372 is arranged outside the first stacked body 371 in the radial direction R. The second laminate 372 includes a plurality of second steel plates 376 stacked in the radial direction R, as shown in FIG. 4 . At this time, the plurality of second steel plates 376 are stacked so that the center line of the second steel plates 376 is along the radial direction R. In FIG. 5, the length of the second steel plate 376 in the circumferential direction T is defined as "second length s12." Here, the length of the second steel plate 376 in the circumferential direction T refers to the length of the second steel plate 376 in a direction perpendicular to the center line 350 within a plane seen when the first divided yoke 35 is viewed from above. The second length s12 is set longer than the first length s11. In addition, in each figure except FIG. 4, illustration of each outline of the 1st steel plate 375 and the 2nd steel plate 376 is abbreviate|omitted.

The second divided yoke 36 shown in FIG. 4 includes a first stacked body 381 and a second stacked body 382.
The first stacked body 381 includes a plurality of first steel plates 385 stacked in the radial direction R, as shown in FIG. 4 . At this time, the plurality of first steel plates 385 are stacked so that the center line of the first steel plates 385 is along the radial direction R. In FIG. 5, the length of the first steel plate 385 in the circumferential direction T is defined as "first length s21." Here, the length of the first steel plate 385 in the circumferential direction T refers to the length of the first steel plate 385 in a direction perpendicular to the center line 360 within a plane seen when the second divided yoke 36 is viewed from above.

The second stacked body 382 is arranged outside the first stacked body 381 in the radial direction R. The second laminate 382 includes a plurality of second steel plates 386 stacked in the radial direction R, as shown in FIG. 4 . At this time, the plurality of second steel plates 386 are stacked so that the center line of the second steel plates 386 is along the radial direction R. In FIG. 5, the length of the second steel plate 386 in the circumferential direction T is defined as "second length s22." Here, the length of the second steel plate 386 in the circumferential direction T refers to the length of the second steel plate 386 in a direction perpendicular to the center line 360 within a plane seen when the second divided yoke 36 is viewed from above. The second length s22 is set longer than the first length s21. In addition, in each figure except FIG. 4, illustration of each outline of the 1st steel plate 385 and the 2nd steel plate 386 is abbreviate|omitted.

The first steel plate 375, the second steel plate 376, the first steel plate 385, and the second steel plate 386 are each made of a magnetic material. Examples of the magnetic material include electromagnetic steel sheets, amorphous alloy foils, magnetic powder compacts, and the like.

In FIG. 5, the length of the first laminate 371 in the radial direction R is h11, and the length of the second laminate 372 is h12. In other words, the length of the first stacked body 371 along the center line 350 is h11, and the length of the second stacked body 372 is h12. Further, in FIG. 5, the length of the first stacked body 381 in the radial direction R is set to h21, and the length of the second stacked body 382 is set to h22. In other words, the length of the first laminate 381 along the center line 360 is h21, and the length of the second laminate 382 is h22. In this embodiment, the ratio between the length h11 and the length h12 in the first divided yoke 35 and the ratio between the length h21 and the length h22 in the second divided yoke 36 are different from each other.

Specifically, in this embodiment, the ratio of the length h11 of the first stacked body 371 in the radial direction R to the length h12 of the second stacked body 372 is 2:1. On the other hand, the ratio of the length h21 of the first stacked body 381 in the radial direction R to the length h22 of the second stacked body 382 is 1:2. That is, in this embodiment, the ratio h11:h12 and the ratio h21:h22 are reciprocals of each other.

According to such a configuration, the gap 33 between the first divided yoke 35 and the second divided yoke 36 can be reduced. Thereby, the flatness precision of the facing surface 342 of the yoke 34 can be improved. By arranging the magnets 39 on such a facing surface 342, the flatness accuracy of the first rotor 3, that is, the flatness accuracy of the surface facing the stator 5 of the first rotor 3 is increased, so that the first rotor Variation in the distance (air gap amount) between the air gap 11 and the stator 5 can be suppressed.

If the in-plane uniformity of the air gap amount can be improved, vibrations and the like during rotation will be suppressed and rotational stability will be improved. Further, since the air gap amount can be made smaller, the axial gap motor 1 can be made to have a higher torque or be made smaller without impairing the torque. Therefore, by increasing the flatness accuracy of the facing surface 342, the performance of the axial gap motor 1 can be improved.

Moreover, if the gap 33 can be made small, it is possible to suppress the deterioration of the magnetic properties of the yoke 34 due to the gap 33. As a result, it is possible to increase the torque of the axial gap motor 1 or to reduce its size without impairing the torque. Further, since changes in magnetic resistance of the magnetic path passing through the yoke 34 can be suppressed, cogging torque can also be reduced.

Further, the first steel plate 375, the second steel plate 376, the first steel plate 385, and the second steel plate 386 may be plate materials cut out in advance into a predetermined shape by, for example, die cutting, laser processing, or the like. Therefore, the dimensional accuracy of these steel plates can be easily improved. As a result, in the first laminated body 371, the second laminated body 372, the first laminated body 381, and the second laminated body 382, the end faces of each steel plate exposed on the opposing surface 342 shown in FIG. 1 are aligned with high positional accuracy. It becomes something. Therefore, the facing surface 342 of the yoke 34 has higher flatness accuracy. Flatness accuracy refers to high flatness and high perpendicularity to the rotation axis AX.

Furthermore, since high flatness accuracy can be achieved simply by laminating steel plates, secondary machining after lamination is not required or the amount of machining can be reduced. This makes it possible to eliminate problems associated with secondary processing, such as a decrease in the insulation between steel plates, generation of internal stress due to processing, and an increase in the number of man-hours.

Furthermore, by making the first length s11 and the first length s21 equal, and making the second length s12 and the second length s22 equal, the first divided yoke 35 can be Then, the second divided yoke 36 can be manufactured. Specifically, by making the first length s11 and the first length s21 equal, there is no need to distinguish between the first steel plate 375 and the first steel plate 385, so that steel plates of one size can be used as the first steel plate. 375 and the first steel plate 385. Similarly, by making the second length s12 and the second length s22 equal, there is no need to distinguish between the second steel plate 376 and the second steel plate 386, so that steel plates of one size can be used as the second steel plate 376 and the second steel plate 386. It can be used as the second steel plate 386. Thereby, the cost of the yoke 34 can be easily reduced.

In particular, when the first steel plate 375, the second steel plate 376, the first steel plate 385, and the second steel plate 386 are each made of die-cut materials, it is easy to improve the dimensional accuracy of each steel plate, and it is also easy to reduce costs. Since the die-cut material is formed by cutting a plate-shaped steel plate, the end faces of the die-cut material have small variations in shape. Therefore, by using the die cut material, the flatness accuracy of the facing surface 342 of the yoke 34 can be particularly improved. For example, when the yoke 34 shown in FIG. 3 is constructed from a die-cut material, two types of rectangular die-cut materials with different lengths may be prepared. In addition, since only two types of cutting dies are required to produce the cutting material, the procurement cost of cutting dies can be reduced.

Further, the first stacked body 371 includes a plurality of first steel plates 375 stacked in the radial direction R. By stacking the first steel plates 375 in the radial direction R in this way, the path through which eddy currents generated in response to changes in magnetic flux flow can be sufficiently shortened, and eddy current loss can be reduced. can. Specifically, the magnetic field by the magnet 39 is formed along the circumferential direction T, as shown by magnetic flux lines ML in FIG. Therefore, by stacking the first steel plates 375 in the radial direction R, the path of the eddy current that flows as the magnetic flux changes along the circumferential direction T can be divided sufficiently short. Note that the second laminate 372, the first laminate 381, and the second laminate 382 are also similar to the first laminate 371.

Note that the ratio between the length h11 and the length h12 and the ratio between the length h21 and the length h22 may be different from each other, but from the viewpoint of reducing the gap 33, the following conditions are satisfied. It is preferable to meet the requirements.

In FIG. 5, the length H1 is the sum of the length h11 and the length h12. In the first divided yoke 35, the ratio h11/H1 of the length h11 of the first laminate 371 to the length H1 is preferably 55% or more and 80% or less, more preferably 60% or more and 72% or less. preferable.

Similarly, in FIG. 5, the length H2 is the sum of the length h21 and the length h22. Note that the length H2 is equal to the length H1. In the second divided yoke 36, the ratio h22/H2 of the length h22 of the second laminate 382 to the length H2 is preferably 55% or more and 80% or less, more preferably 60% or more and 72% or less. preferable.

By setting as described above, the gap 33 between the first divided yoke 35 and the second divided yoke 36 can be made sufficiently small. Thereby, the flatness accuracy of the first rotor 3 can be further improved.

FIG. 6 shows the calculation of the relationship between the layer thickness ratio (h11/H1) and the area ratio of the yoke 34, when the ratio of the length h11 to the length H1 is the “layer layer thickness ratio (h11/H1)”. This is the graph obtained. The area ratio of the yoke 34 is the area excluding the gap 33 between the first divided yoke 35 and the second divided yoke 36 in plan view when the yoke 34 is composed of the first divided yoke 35 and the second divided yoke 36. Refers to the area ratio of (substantial part). Note that the graph shown in FIG. 6 was derived using a model in which the number of magnetic poles is 24, the distance from the inner end surface of the yoke 34 to the rotation axis AX in the radial direction R is 90 mm, and the lengths H1 and H2 are 18 mm. There is. In addition, in this model, when the value of the stacked layer thickness ratio (h11/H1) in the first divided yoke 35 is changed, the layered layer thickness ratio (h22/H2) in the second divided yoke 36 is set to the same value. It is set to be. That is, the ratio h11:h12 and the ratio h21:h22 are set to be reciprocals of each other.

As shown in FIG. 6, the graph showing the relationship between the stacked layer thickness ratio (h11/H1) and the area ratio of the yoke 34 is an upwardly convex curve with a maximum value of about 96%. The stacked layer thickness ratio (h11/H1) corresponding to this maximum value is about 67%. In other words, it can be said that the gap 33 is the smallest when the ratio of h11:h12 is 2:1 and the ratio of h21:h22 is 1:2.

FIG. 7 is a diagram showing, as a first reference example, a model in which the first divided yoke 35A and the second divided yoke 36A are composed of two laminates 71A and 73A having different lengths in the circumferential direction T, respectively. Moreover, FIG. 8 is a graph obtained by calculating the relationship between the lower stage height ratio (h71A/H3) and the area ratio of the yoke 34A for the model shown in FIG. In the following description, the laminate 71A will be referred to as a "lower tier" and the laminate 73A will be referred to as an "upper tier". The length of the lower tier in the radial direction R is defined as "length h71A", and the total length of the lower tier and the length of the upper tier is defined as "length H3". The "lower stage height ratio (h71A/H3)" mentioned above is the ratio of the length h71A to the length H3. The area ratio of the yoke 34A is the area excluding the gap 33A between the first divided yoke 35A and the second divided yoke 36A in plan view when the yoke 34A is composed of the first divided yoke 35A and the second divided yoke 36A. Refers to the area ratio of (substantial part).

In the first reference example shown in FIGS. 7 and 8, unlike the present embodiment, the condition is that the first divided yoke 35A and the second divided yoke 36A have the same lower height ratio (h71A/H3). Below, the area ratio of the yoke 34A is calculated while changing this parameter. The graph shown in FIG. 8 is an upwardly convex curve with a maximum value of about 94%. The reason why the maximum value of the graph shown in FIG. 8 is lower than that of the graph shown in FIG. 6 is that in the first reference example shown in FIG. The laminate 73A tends to interfere with the laminate 73A, and therefore, it is difficult to make the gap 33A sufficiently small. For this reason, the area ratio of the yoke 34A cannot be sufficiently increased.

FIG. 9 is a diagram showing, as a second reference example, a model in which the first divided yoke 35B and the second divided yoke 36B are composed of three laminates 71B, 72B, and 73B each having a different length in the circumferential direction T. . FIG. 10 is a graph obtained by calculating the relationship between the lower height ratio (h71B/H4), the middle height ratio (h72B/H4), and the area ratio of the yoke 34B for the model shown in FIG. be. In the following description, the laminate 71B will be referred to as a "lower tier," the laminate 72B will be referred to as a "middle tier," and the laminate 73B will be referred to as an "upper tier." Then, the length of the stacked body 71B in the radial direction is "length h71B", the length of the stacked body 72B is "length h72B", and the total length of each of the lower, middle, and upper stages is "length H4". shall be. The above-mentioned "lower height ratio (h71B/H4)" is the ratio of length h71B to length H4, and "middle height ratio (h72B/H4)" is the ratio of length h72B to length H4. It is a ratio. The area ratio of the yoke 34B is the area excluding the gap 33B between the first divided yoke 35B and the second divided yoke 36B in plan view when the yoke 34B is composed of the first divided yoke 35B and the second divided yoke 36B. Refers to the area ratio of (substantial part).

In the second reference example shown in FIGS. 9 and 10, unlike this embodiment, the first divided yoke 35B and the second divided yoke 36B have a lower height ratio (h71B/H4) and a middle height ratio. The area ratio of the yoke 34B is calculated while changing these parameters under the condition that (h72B/H4) are made equal. The graphs shown in FIG. 10 all have upwardly convex curves. In the graph when the lower stage height ratio (h71B/H4) is set to 33.3%, the maximum value is about 96%.

However, in the second reference example, since it is necessary to configure one divided yoke with three laminates, more types of steel plates are required than in this embodiment. Therefore, according to this embodiment, it is possible to reduce the gap 33 between the first divided yoke 35 and the second divided yoke 36 while using fewer types of steel plates, and realize a yoke 34 with high magnetic properties at low cost. can do. By increasing the magnetic properties of the yoke 34, the magnetic flux density in the air gap 11 can be further increased. Thereby, it is possible to increase the torque of the axial gap motor 1 or to reduce its size without impairing the torque. Further, since changes in magnetic resistance of the magnetic path passing through the yoke 34 can be suppressed, cogging torque can also be reduced.

The difference between the first length s11 and the second length s12 and the difference between the first length s21 and the second length s22 in FIG. It is set appropriately depending on the number of second divided yokes 36, etc.

The thickness of each of the first steel plate 375, second steel plate 376, first steel plate 385, and second steel plate 386 shown in FIG. 4 is not particularly limited, but is preferably 0.1 mm or more and 1.0 mm or less, and 0.1 mm or more and 1.0 mm or less. More preferably, it is 2 mm or more and 0.5 mm or less. Thereby, the rigidity of each steel plate can be ensured while sufficiently reducing eddy current loss. As a result, the workability of laminating steel plates can be improved.

Further, the height H of the yoke 34 shown in FIG. 3 is not particularly limited, but is preferably 0.5 mm or more and 10 mm or less, and more preferably 1 mm or more and 5 mm or less. Thereby, the magnetic properties of the yoke 34 can be ensured without hindering the reduction in the height of the axial gap motor 1.

The number of magnets 39 that the first rotor 3 has is determined by the number of phases and the number of poles of the axial gap motor 1. Examples of the magnet 39 include, but are not limited to, neodymium magnets, ferrite magnets, samarium cobalt magnets, alnico magnets, and bonded magnets.

The positional relationship between the first divided yoke 35 and the second divided yoke 36 and the magnet 39 is not particularly limited, but as shown in FIG. 3, the position where the gap 33 overlaps the center O of the magnet 39 in the circumferential direction T It is preferable to set it to . Thereby, since the density of the magnetic flux lines ML is low at the center O of the magnet 39, even if the gap 33 exists in the yoke 34, the increase in magnetic resistance in the magnetic path is limited. Therefore, by setting the positional relationship between the gap 33 and the magnet 39 as described above, even if the yoke 34 has the gap 33, the influence on the torque of the axial gap motor 1 can be kept to a minimum.

Note that the expression that the gap 33 overlaps with the center O refers to a state in which the center O is located inside the gap 33 when the first rotor 3 is viewed from above.

Further, in this embodiment, the yoke 34 shown in FIGS. 3 and 5 includes a filler 82 provided in the gap 33. Filler 82 preferably includes soft magnetic powder. As a result, the magnetic resistance of the magnetic path passing through the yoke 34 can be reduced, so that the magnetic characteristics of the yoke 34 can be further improved. As a result, it is possible to increase the torque of the axial gap motor 1 or to reduce its size without impairing the torque. Further, since changes in magnetic resistance of the magnetic path passing through the yoke 34 can be suppressed, cogging torque can also be reduced. The soft magnetic powder is not particularly limited as long as it is a powder of a material exhibiting soft magnetic properties, and examples thereof include soft magnetic alloy powder, ferrite powder, and the like.

Further, the filler 82 may be a green compact of these soft magnetic powders, or may further contain resin. The resin functions as a binder, binding the particles of the soft magnetic powder to each other, and also has the function of bonding the adjacent first divided yoke 35 and second divided yoke 36 together. Therefore, the reliability of the first rotor 3 can be further improved. Examples of the resin include main components of adhesives, and specific examples include epoxy resins, acrylic resins, urethane resins, silicone resins, and the like.

1.3. Second Rotor The second rotor 4 includes the rotor frame 42, the yoke 44, and the magnet 49, as described above. The rotor frame 42, yoke 44, and magnet 49 are similar to the rotor frame 32, yoke 34, and magnet 39 described above.

Note that in the second rotor 4, the magnet 49 may be omitted. In this case, the magnetic flux lines emitted from the magnets 39 of the first rotor 3 pass through the yoke 44 of the second rotor 4, thereby allowing the second rotor 4 to generate torque.

Further, the configuration of the yoke 44 may be the same as that of the yoke 43, or may be different. For example, the yoke 44 may be composed of one annular component instead of being divided into a plurality of components.

1.4. Effects of the first embodiment As described above, the axial gap motor 1 according to the first embodiment includes the first rotor 3, which is a rotor, and the stator 5. The first rotor 3 has a magnet 39 and a yoke 34 on which the magnet 39 is arranged, and rotates around the rotation axis AX. The stator 5 is arranged apart from the first rotor 3. The yoke 34 has a first divided yoke 35 and a second divided yoke 36. The first divided yoke 35 includes a first stacked body 371 and a second stacked body 372. The second divided yoke 36 includes a first stacked body 381 and a second stacked body 382. The first laminated bodies 371, 381 include a plurality of first steel plates 375, 385, which are laminated in the radial direction R around the rotation axis AX and have first lengths s11, s21 in the circumferential direction T. Contains. The second laminates 372, 382 are arranged outside the first laminates 371, 381 in the radial direction R, and are laminated in the radial direction R. The length in the circumferential direction T is the second length s12. , s22. The second lengths s12 and s22 are set longer than the first lengths s11 and s21.

The ratio h11:h12 of the length h11 of the first laminated body 371 in the radial direction R of the first divided yoke 35 to the length h12 of the second laminated body 372, and the ratio h11:h12 of the second divided yoke 36 in the radial direction R. The ratio h21:h22 of the length h21 of the first stacked body 381 and the length h22 of the second stacked body 382 is different from each other.

According to such a configuration, the gap 33 between the first divided yoke 35 and the second divided yoke 36 can be reduced. Thereby, the flatness precision of the facing surface 342 of the yoke 34 can be improved. By arranging the magnets 39 on such a facing surface 342, the flatness accuracy of the first rotor 3 is increased, so that the distance of the air gap 11 (air gap amount) between the first rotor 3 and the stator 5 is reduced. Variation can be suppressed. As a result, the rotational stability of the axial gap motor 1 can be improved, and the torque can be increased or the size can be reduced without impairing the torque. Further, since changes in magnetic resistance of the magnetic path passing through the yoke 34 can be suppressed, cogging torque can also be reduced.

Further, in this embodiment, the yoke 34 has a facing surface 342 facing the stator 5. The magnet 39 is arranged on this opposing surface 342.

Thereby, variations in the distance (air gap amount) of the air gap 11 located between the magnet 39 and the stator 5 can be suppressed. As a result, the rotational stability of the axial gap motor 1 is improved, and by making the air gap amount smaller, the axial gap motor 1 can be made higher in torque or smaller in size.

Further, in the present embodiment, the first laminate body is It is preferable that the ratio h11/H1 of the length h11 of 371 is 55% or more and 80% or less. Furthermore, the length h22 of the second laminate 382 is relative to the sum (length H2) of the length h21 of the first laminate 381 and the length h22 of the second laminate 382 in the radial direction R of the second divided yoke 36. The ratio h22/H2 is preferably 55% or more and 80% or less.

Thereby, the gap 33 between the first divided yoke 35 and the second divided yoke 36 can be made sufficiently small. As a result, the flatness accuracy of the first rotor 3 can be further improved.

Further, in this embodiment, the yoke 34 includes a filler 82. The filler 82 is provided in the gap 33 between the first divided yoke 35 and the second divided yoke 36, and contains soft magnetic powder.
According to such a configuration, the magnetic properties of the yoke 34 can be further improved.

Moreover, it is preferable that the filler 82 contains resin. The resin functions as a binder, binding the particles of the soft magnetic powder to each other, and also has the function of bonding the adjacent first divided yoke 35 and second divided yoke 36 together. Therefore, the reliability of the first rotor 3 can be further improved.

Moreover, it is preferable that the first steel plates 375, 385 and the second steel plates 376, 386 are die cut materials. By using a die cut material, the dimensional accuracy of each steel plate can be improved, and costs can also be easily reduced. Further, since the end face of the die cut material has small variations in shape, this contributes to particularly improving the flatness accuracy of the facing surface 342 of the yoke 34.

2. Modification Next, an axial gap motor according to a modification will be described.

FIG. 11 is a partial plan view of the yoke of the first rotor 3 of the axial gap motor 1C according to the first modification.

The first modified example will be described below. In the following explanation, the differences from the first embodiment will be mainly explained, and the explanation of similar matters will be omitted. Note that in FIG. 11, the same components as in the first embodiment are designated by the same reference numerals.

The first rotor 3 of the axial gap motor 1C shown in FIG. 11 has a positioning pin 84 (positioning member). The positioning pin 84 is provided in the gap 33 between the first divided yoke 35 and the second divided yoke 36, and regulates the positions of the outer shapes of the first divided yoke 35 and the second divided yoke 36. Thereby, the positions of the first divided yoke 35 and the second divided yoke 36 can be accurately determined to be appropriate positions with respect to the rotor frame 32 (not shown in FIG. 11). As a result, it is possible to optimize the magnetic flux density distribution in the air gap 11 and increase the torque of the axial gap motor 1C. Note that the positioning pin 84 only needs to be fixed to the rotor frame 32 (not shown in FIG. 11). Moreover, the positioning pin 84 may be provided at a position other than the gap 33.

The positioning pin 84 is a rod-shaped member extending in the Z-axis direction, but its cross-sectional shape is not particularly limited, and may be circular, square, or other shapes.

Further, the positioning member is not limited to the positioning pin 84 shown in FIG. 11, but may be a key, for example. When a key is used as the positioning member, key grooves may be provided in advance in the first divided yoke 35 and the second divided yoke 36.

As the constituent material of the positioning member, for example, non-magnetic materials such as resin materials and ceramic materials are preferably used.

Further, depending on the method of assembling the first rotor 3, an assembly jig including positioning pins 84 may be used. Specifically, first, the first divided yoke 35 and the second divided yoke 36 are placed on a jig provided with the positioning pins 84 to form the yoke 34. By using the positioning pins 84, the first divided yoke 35 and the second divided yoke 36 can be accurately aligned. Next, a magnet 39 is bonded to the manufactured yoke 34. As a result, an assembly of the yoke 34 and the magnet 39 is obtained. By housing this in the rotor frame 32, the first rotor 3 is obtained.

As described above, in the axial gap motor 1C according to the first modification, the first rotor 3 has the positioning pin 84 (positioning member). The positioning pin 84 is provided in the gap 33 between the first divided yoke 35 and the second divided yoke 36, and has the function of positioning the first divided yoke 35 and the second divided yoke 36.

According to such a configuration, the positions of the first divided yoke 35 and the second divided yoke 36 can be determined with high accuracy. Thereby, it is possible to optimize the magnetic flux density distribution in the air gap 11 and increase the torque of the axial gap motor 1C.

FIG. 12 is a partial sectional view showing the first rotor 3 of the axial gap motor 1D according to the second modification.

Hereinafter, the second modification will be described. In the following explanation, the differences from the first embodiment will be mainly explained, and the explanation of similar matters will be omitted. Note that in FIG. 12, the same components as in the first embodiment are designated by the same reference numerals.

The yoke 34D of the first rotor 3 of the axial gap motor 1D shown in FIG. 12 has a convex portion 85. The convex portion 85 is located at the center of each of the first divided yoke 35 and the second divided yoke 36 in the circumferential direction T, and protrudes upward. Thereby, when the magnets 39 are arranged on the upper surface of the yoke 34D, the protrusions 85 can be used to position the magnets 39. As a result, the position of the magnet 39 relative to the yoke 34D can be determined with high precision, and even if the yoke 34D has the gap 33, as described above, the influence on the torque of the axial gap motor 1D can be minimized. It can be fastened. Further, it is possible to suppress changes in magnetic resistance of the magnetic path passing through the yoke 34D, and it is also possible to reduce cogging torque.

FIG. 13 is a partial plan view showing the first rotor 3 of the axial gap motor 1E according to the third modification.

Hereinafter, the third modification will be described. In the following explanation, the differences from the first embodiment will be mainly explained, and the explanation of similar matters will be omitted. Note that in FIG. 13, the same components as in the first embodiment are designated by the same reference numerals.

The first divided yoke 35E of the first rotor 3 of the axial gap motor 1E shown in FIG. 13 includes a first laminate 371, a second laminate 372, and a third laminate 373. The first laminate 371, the second laminate 372, and the third laminate 373 are arranged in this order from the inside to the outside in the radial direction R.

The second divided yoke 36E includes a first laminate 381, a second laminate 382, and a third laminate 383. The first laminate 381, the second laminate 382, and the third laminate 383 are arranged in this order from the inside to the outside in the radial direction R.

In FIG. 13, the length of the third laminate 373 in the radial direction R is h13, and the length of the third laminate 383 is h23. Then, the ratio of the length h11 to the length h12 to the length h13 in the first divided yoke 35E and the ratio of the length h21 to the length h22 to the length h23 in the second divided yoke 36E are different from each other. There is.

In the third modification, as an example, the ratio of length h11, length h12, and length h13 is 4:3:2. On the other hand, the ratio of length h21, length h22, and length h23 is 2:3:4.

According to such a configuration, similarly to the first embodiment, the gap 33E between the first divided yoke 35E and the second divided yoke 36E can be reduced. As a result, the same effect as in the first embodiment can be achieved, specifically, it is possible to suppress the deterioration of the magnetic properties of the yoke 34E, and it is possible to increase the torque of the axial gap motor 1E or to reduce its size without impairing the torque. can. Further, since changes in magnetic resistance of the magnetic path passing through the yoke 34E can be suppressed, cogging torque can also be reduced.

3. Second Embodiment Next, a robot according to a second embodiment will be described.

FIG. 14 is a perspective view showing a robot 1000 according to the second embodiment.
As shown in FIG. 14, the robot 1000 is used, for example, in various operations such as transporting, assembling, and inspecting various workpieces (objects). The robot 1000 includes a base 1001, a robot arm 1100, and drive units 1501, 1502, 1503, 1504, 1505, and 1506.

The base 1001 is placed on a horizontal floor 2000. Note that the base 1001 may be placed not on the floor 2000 but on a wall, ceiling, pedestal, or the like.

The robot arm 1100 includes a first arm 1010, a second arm 1020, a third arm 1030, a fourth arm 1040, a fifth arm 1050, and a sixth arm 1060. An end effector (not shown) can be removably attached to the tip of the sixth arm 1060, and the end effector can grip a workpiece.

Examples of the end effector include, but are not limited to, a hand that grips a workpiece, a suction head that suctions a workpiece, and the like. The work to be gripped by the end effector is not particularly limited, and examples thereof include electronic parts, electronic equipment, and the like. In addition, in this specification, the base 1001 side when the sixth arm 1060 is the reference is referred to as the "base end side", and the sixth arm 1060 side when the base 1001 is the reference is referred to as the "distal end side". .

The robot 1000 has a base 1001, a first arm 1010, a second arm 1020, a third arm 1030, a fourth arm 1040, a fifth arm 1050, and a sixth arm 1060 from the base end side. It is a single-arm, 6-axis, vertically articulated robot that is connected in this order toward the tip.

The lengths of the first arm 1010 to the sixth arm 1060 are not particularly limited and can be set as appropriate. Note that the number of arms that the robot arm 1100 has may be 1 to 5 or 7 or more. Additionally, the robot 1000 may be a SCARA robot or a dual-arm robot with two or more robot arms 1100.

The base 1001 and the first arm 1010 are connected via a joint (not shown). The first arm 1010 is rotated by driving of a motor 1501m and a drive unit 1501 having a speed reducer (not shown). The motor 1501m generates thrust that rotates the first arm 1010.

The first arm 1010 and the second arm 1020 are connected via a joint (not shown). The second arm 1020 is rotated by driving of a motor 1502m and a drive unit 1502 having a speed reducer (not shown). The motor 1502m generates thrust that rotates the second arm 1020.

The second arm 1020 and the third arm 1030 are connected via a joint (not shown). The third arm 1030 is rotated by driving of a motor 1503m and a drive unit 1503 having a speed reducer (not shown). The motor 1503m generates thrust that rotates the third arm 1030.

The third arm 1030 and the fourth arm 1040 are connected via a joint (not shown). The fourth arm 1040 is rotated by driving of a motor 1504m and a drive unit 1504 having a speed reducer (not shown). The motor 1504m generates thrust that rotates the fourth arm 1040.

The fourth arm 1040 and the fifth arm 1050 are connected via a joint (not shown). The fifth arm 1050 is rotated by driving of a motor 1505m and a drive unit 1505 having a speed reducer (not shown). The motor 1505m generates thrust that rotates the fifth arm 1050.

The fifth arm 1050 and the sixth arm 1060 are connected via a joint (not shown). The sixth arm 1060 is rotated by driving of a motor 1506m and a drive unit 1506 having a speed reducer (not shown). The motor 1506m generates thrust that rotates the sixth arm 1060.

The axial gap motor according to the embodiment or each modification is used as at least one of these motors 1501m to 1506m. That is, the robot 1000 includes the axial gap motor according to the embodiment or each modification. By using such an axial gap motor, it is possible to increase the torque of the motors 1501m to 1506m or to reduce their size, thereby improving the performance of the robot arm 1100.

Further, the driving units 1501 to 1506 are provided with angle sensors (not shown). Examples of these angle sensors include various encoders such as a rotary encoder. The angle sensor detects the rotation angle of the output shaft of the motors 1501m to 1506m or the reducer.

The drive units 1501 to 1506 and the angle sensor are each electrically connected to a robot control device (not shown). The robot control device independently controls the operations of drive units 1501 to 1506.

Note that when the robot 1000 is equipped with the axial gap motor according to the embodiment or each modification, the shaft 2 shown in FIG. 1 can be made hollow, so that wiring can be passed through the hollow space. Thereby, the wiring efficiency in the robot arm 1100 can be improved. In addition, by providing the above-mentioned axial gap motor, the robot 1000 can have a higher output than the conventional robot 1000.

Although the axial gap motor and robot according to the present invention have been described above based on the illustrated embodiments or each modification, the present invention is not limited thereto.

For example, in the axial gap motor and robot according to the present invention, each part of the embodiment or each modification may be replaced with an arbitrary structure having a similar function, or Arbitrary components may be added to the modified example.

Further, the axial gap motor according to the present invention is not limited to the two-rotor, one-stator type motor as in the embodiment or each modification example. In particular, the number of rotors and the number of stators are not limited to those in the above embodiments, and for example, a one-rotor, one-stator type motor may be used.

Further, the number of types of split yokes included in the rotor of the axial gap motor according to the present invention is not limited to two types, and may be three or more types. Further, the number of stacked bodies included in one divided yoke is not limited to the aforementioned two or three, but may be four or more. Further, the shape of the steel plate constituting the split yoke is not limited to a rectangle or a shape including a convex portion, but may be any other shape.

1... Axial gap motor, 1C... Axial gap motor, 1D... Axial gap motor, 1E... Axial gap motor, 2... Shaft, 3... First rotor, 4... Second rotor, 5... Stator, 6... Motor case, 11 ...Air gap, 12...Air gap, 32...Rotor frame, 33...Gap, 33A...Gap, 33B...Gap, 33E...Gap, 34...Yoke, 34A...Yoke, 34B...Yoke, 34D...Yoke, 34E...Yoke, 35...first divided yoke, 35A...first divided yoke, 35B...first divided yoke, 35E...first divided yoke, 36...second divided yoke, 36A...second divided yoke, 36B...second divided yoke, 36E ...Second divided yoke, 39...Magnet, 42...Rotor frame, 43...Yoke, 44...Yoke, 49...Magnet, 52...Stator core, 53...Teeth portion, 54...Coil, 61...First case, 62...Nth 2 case, 63... Side case, 71A... Laminated body, 71B... Laminated body, 72B... Laminated body, 73A... Laminated body, 73B... Laminated body, 82... Filler, 84... Positioning pin, 85... Convex part, 322... Through hole, 324... recess, 342... opposing surface, 350... center line, 360... center line, 371... first laminate, 372... second laminate, 373... third laminate, 375... first steel plate, 376 ...second steel plate, 381...first laminate, 382...second laminate, 383...third laminate, 385...first steel plate, 386...second steel plate, 1000...robot, 1001...base, 1010...th 1 arm, 1020...Second arm, 1030...Third arm, 1040...Fourth arm, 1050...Fifth arm, 1060...Sixth arm, 1100...Robot arm, 1501...Drive unit, 1501m...Motor, 1502...Drive Part, 1502m...Motor, 1503...Drive unit, 1503m...Motor, 1504...Drive unit, 1504m...Motor, 1505...Drive unit, 1505m...Motor, 1506...Drive unit, 1506m...Motor, 2000...Floor, AX...Rotation axis , ML... Line of magnetic flux, O... Center, R... Radial direction, T... Circumferential direction

Claims (8)

a rotor having a magnet and a yoke in which the magnet is arranged, and rotating around a rotation axis;
a stator disposed apart from the rotor;
Equipped with
The yoke includes a first divided yoke and a second divided yoke adjacent to the first divided yoke in a circumferential direction centered on the rotation axis,
The first divided yoke and the second divided yoke each include a first laminate and a second laminate,
The first laminate includes a plurality of first steel plates that are stacked in a radial direction around the rotation axis and have a first length in the circumferential direction,
The second laminate is disposed outside the first laminate in the radial direction, and is laminated in the radial direction, and has a second length in the circumferential direction that is longer than the first length. including a plurality of second steel plates,
The axial gap motor is characterized in that the first divided yoke and the second divided yoke have different ratios of the length of the first stacked body and the length of the second stacked body in the radial direction. The yoke has a facing surface facing the stator,
The axial gap motor according to claim 1, wherein the magnet is arranged on the opposing surface. In the first divided yoke, the ratio of the length of the first laminate to the sum of the length of the first laminate and the length of the second laminate in the radial direction is 55% or more and 80% or less. can be,
In the second divided yoke, a ratio of the length of the second laminate to the sum of the length of the first laminate and the length of the second laminate in the radial direction is 55% or more and 80% or less. An axial gap motor according to claim 1 or 2. 3. The axial gap motor according to claim 1, wherein the yoke includes a filler containing soft magnetic powder in a gap between the first divided yoke and the second divided yoke. The axial gap motor according to claim 4, wherein the filler contains resin. The axial gap motor according to claim 1 or 2, wherein the rotor includes a positioning member for positioning the first divided yoke and the second divided yoke in a gap between the first divided yoke and the second divided yoke. . The axial gap motor according to claim 1 or 2, wherein the first steel plate and the second steel plate are die-cut materials. A robot comprising the axial gap motor according to claim 1 or 2.

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