Motor

Abstract

To provide a motor with high efficiency for washing machines.SOLUTION: A motor includes a rotor that rotates around a rotating shaft, and a stator facing the rotor across a gap in an axial direction of the rotating shaft, in which the rotor has a magnet whose magnetic poles are directed in the axial direction, the stator has a stator core formed by a magnetic material that circulates magnetically and a coil that forms magnetic poles in the axial direction, and the stator core is formed by combining teeth around which the coil is wound and a yoke separated from the teeth.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a motor for a washing machine. [Background technology]

[0002] It is desirable for washing machine motors to have high efficiency. In conventional motors, the teeth and yoke are molded as a single unit. In motors where the teeth and yoke are molded as a single unit, eddy currents tend to occur in the teeth and the magnetic flux density tends to increase, making it difficult to improve the motor's efficiency. On the other hand, motors that combine separately molded teeth and a yoke have been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-108323 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a motor with high efficiency. [Means for solving the problem]

[0005] The motor of the washing machine in this embodiment comprises a rotor that rotates around a rotating shaft, and a stator that faces the rotor across a gap in the axial direction of the rotating shaft, the rotor having a magnet whose magnetic pole direction is in the axial direction, the stator having a starter core formed of a magnetic material that circulates magnetically, and a coil that forms a magnetic pole in the axial direction, and the starter core is formed by combining teeth around which the coil is wound and a yoke that is separate from the teeth. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view of a washing machine having a motor according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is a cross-sectional schematic diagram of the stator of the motor. [Figure 4] FIG. [Figure 5] FIG. 3 is a diagram showing the stator as viewed from the axial direction. [Figure 6] FIG. 10 is a cross-sectional view of a modified example of the teeth of the stator. [Figure 7] FIG. 10 is a cross-sectional view of another modified example of the tooth. [Figure 8] FIG. 10 is a cross-sectional view of another modified example of the tooth. [Figure 9] FIG. 10 is a cross-sectional view of a modified example of the stator core of the stator. [Figure 10] FIG. 10 is a cross-sectional view of another modified example of the tooth. [Figure 11] FIG. 10 is a cross-sectional view of the teeth fixed by caulking. [Figure 12] 10A and 10B are diagrams showing modified examples of the yoke of the stator. [Figure 13] 10A and 10B are diagrams showing other modified examples of the yoke of the stator. [Figure 14] FIG. 4 is a view showing a through hole formed in the yoke. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a motor and a washing machine according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplicate descriptions of those components may be omitted.

[0008] FIG. 1 is a cross-sectional view of a washing machine having a motor according to this embodiment. In the following description, the side of the installation surface of the washing machine, i.e., the vertically lower side, is referred to as the lower side of the washing machine, and the opposite side of the installation surface, i.e., the vertically upper side, is referred to as the upper side of the washing machine. Furthermore, left and right are defined based on the direction in which the washing machine is viewed from a user standing in front of the washing machine. Furthermore, the side closer to the user standing in front of the washing machine as viewed from the washing machine is defined as the "front," and the side further away is defined as the "rear." In this specification, the "width direction" refers to the left-right direction defined above. In this specification, the "depth direction" refers to the front-to-back direction defined above. In the drawings, the +X direction is the right direction, the -X direction is the left direction, the +Y direction is the rear direction, the -Y direction is the front direction, the +Z direction is the up direction, and the -Z direction is the down direction.

[0009] In the following description, the axial direction of the central axis J will be simply referred to as the "axial direction D." In this embodiment, the central axis J is disposed so as to tilt downward from the front to the rear. Of the two sides of the axial direction D, the direction facing forward and diagonally upward may be referred to as the "one axial side D1," and the direction facing rearward and diagonally downward may be referred to as the "other axial side D2." Furthermore, the radial direction centered on the central axis J may be simply referred to as the "radial direction R." Furthermore, the circumferential direction centered on the central axis J may be simply referred to as the "circumferential direction C."

[0010] [Washing machine 1] Washing machine 1 has a housing 2, a door 2a, a water receiving tub 3, a drum (rotating tub) 4, a motor 10, a water inlet pipe 5, and a drain pipe 6. Washing machine 1 is a drum-type washing machine. However, washing machine 1 may also be a vertical-axis type washing machine.

[0011] The housing 2 is made of, for example, steel plate and has an overall rectangular box shape. The housing 2 houses a water receiving tub 3, a drum 4, a motor 10, a water inlet pipe 5, and a drain pipe 6. The housing 2 forms the exterior of the washing machine 1. An entrance 2b is provided in a side wall panel located in the front of the housing 2. A door 2a is attached to the entrance 2b. The door 2a covers the entrance 2b.

[0012] The door 2a can be operated from the front by a user to either a closed state or an open state. When the door 2a is in the closed state, the entrance 2b is closed. When the door 2a is in the open state, the entrance 2b is open.

[0013] Water receiving tub 3 is fixed to the inner surface of housing 2 via a suspension or the like. Water receiving tub 3 is cylindrical and disposed about central axis J. Water receiving tub 3 is disposed in an inclined state, descending from the front to the rear.

[0014] The water receiving tub 3 has a cylindrical portion 3d centered on the central axis J, and a bottom portion 3e that covers an opening on the other axial side D2 of the cylindrical portion 3d. In other words, the water receiving tub 3 is a bottomed cylinder that opens on one axial side D1. A drum 4 is housed in the internal space of the water receiving tub 3. A stator 30 of the motor 10 is fixed to the surface of the bottom portion 3e of the water receiving tub 3 facing the other axial side D2. The opening on the one axial side D1 of the water receiving tub 3 is closed by a door 2a that can be opened and closed.

[0015] The drum 4 has a drum cylindrical portion 4d centered on the central axis J, and a drum bottom portion 4e covering an opening on the other axial side D2 of the drum cylindrical portion 4d. That is, the drum 4 is a bottomed cylindrical body that opens on one axial side D1. A rotating shaft 40 extending from the rotor 20 of the motor 10 is fixed to the drum bottom portion 4e. That is, the drum 4 is connected to the rotor 20. This allows the drum 4 to rotate around the central axis J.

[0016] An opening on one axial side D1 of the drum 4 faces the entrance 2b. When the door 2a is open, the interior of the drum 4 is open to the front through the entrance 2b. Laundry is thrown into the drum 4 through the entrance 2b.

[0017] A plurality of through holes 4b are formed in the drum cylindrical portion 4d. The internal space of the drum 4 is connected to the external space of the drum 4 through the plurality of through holes 4b. Water introduced into the water receiving tank 3 enters the interior of the drum 4 through the through holes 4b.

[0018] A plurality of baffles 4a are fixed to the inner surface of the drum cylindrical portion 4d. Each of the baffles 4a moves in a circumferential direction C around the central axis J as the drum 4 rotates. The laundry inside the drum 4 is agitated by being caught by each of the baffles 4a while moving in the circumferential direction C and then falling due to gravity.

[0019] The water filling pipe 5 is disposed above the water receiving tank 3. The water filling pipe 5 is connected to a water faucet via a water supply valve or the like. The water filling pipe 5 fills water into the water receiving tank 3. The drain pipe 6 is disposed at the very bottom of the water receiving tank 3. A drain valve is provided on the drain pipe 6. The drain pipe 6 drains the water stored in the water receiving tank 3.

[0020] [Motor 10] FIG. 2 is a schematic cross-sectional view of the motor 10. Motor 10 is an axial gap motor. Typically, a radial gap motor, in which a coil and a magnet face each other in the radial direction R, is used to rotate the drum of a washing machine. With a radial gap motor, reducing the axial dimension D of the coil and magnet to reduce the thickness of the motor reduces the facing area between the coil and the magnet, making it difficult to achieve sufficient rotational speed and rotational torque. In contrast, with an axial gap motor, it is easy to ensure a large facing area between the coil and the magnet, making it easy to increase the rotational speed and torque of the motor even when the motor is thinned. According to this embodiment, by using an axial gap motor as motor 10 to rotate drum 4 of washing machine 1, motor 10 can be thinned while ensuring sufficient rotational speed and torque. Thinning motor 10, which is located behind water receiving tub 3, reduces the space behind water receiving tub 3, allowing washing machine 1 to be downsized in the front-to-rear direction.

[0021] The motor 10 comprises a rotor 20 that rotates around a central axis J, a rotating shaft 40 connected to the rotor 20, a stator 30 that faces the rotor 20 via a gap in the axial direction D of the central axis J, and a bearing 5p.

[0022] [Rotor 20] Rotor 20 is located on the other axial side D2 of stator 30. Rotor 20 is fixed to rotating shaft 40. As described above, stator 30 is also fixed to bottom 3e of water receiving tub 3. Drum bottom 4e of drum 4, bottom 3e of water receiving tub 3, stator 30, and rotor 20 are arranged in this order from one axial side D1 toward the other axial side D2.

[0023] The rotating shaft 40 extends about the central axis J. The rotating shaft 40 is fixed to the rotor 20 and rotates together with the rotor 20 about the central axis J. The rotating shaft 40 passes through a through hole 3h provided in the center of the bottom 3e of the water receiving tub 3. A seal structure (not shown) is provided between the through hole 3h and the rotating shaft 40. The rotating shaft 40 is rotatably supported by the stator 30 via a bearing 5p. The rotating shaft 40 is fixed to the drum bottom 4e of the drum 4 at an end on one axial side D1. That is, the rotor 20 is fixed to the drum bottom 4e of the drum 4 via the rotating shaft 40. The torque of the rotor 20 is transmitted to the drum 4 via the rotating shaft 40.

[0024] The rotor 20 has a back yoke 21, a plurality of magnets 24, and a rotor holding portion 29. The rotor 20 is annular in shape and has a center on a central axis J. The back yoke 21 is located on the other axial side D2 of the magnets 24. The rotor 20 is fixed to a rotating shaft 40 at the back yoke 21.

[0025] The rotor holding portion 29 is formed by insert molding, in which the back yoke 21 and the plurality of magnets 24 are embedded. The rotor holding portion 29 holds the back yoke 21 and the plurality of magnets 24.

[0026] The multiple magnets 24 are aligned along a circumferential direction C centered on the central axis J. The magnets 24 have their magnetic poles oriented in the axial direction D. The multiple magnets 24 aligned in the circumferential direction C are arranged with their north and south poles alternately reversed. The magnets 24 are held by a rotor holding portion 29.

[0027] In this embodiment, the magnet 24 is a ferrite magnet, but the magnet 24 may also be another type of magnet (for example, a rare earth magnet such as a neodymium magnet).

[0028] The magnet 24 may be an anisotropic magnet or an isotropic magnet. When the magnet 24 is an anisotropic magnet, the easy axis of magnetization of the magnet 24 is set in the axial direction D, thereby increasing the overall magnetic force of the magnet 24 in the axial direction D. On the other hand, when an isotropic magnet is used as the magnet 24, the rotor 20 can be manufactured more cheaply than when an anisotropic magnet is used.

[0029] [Stator 30] FIG. 3 is a schematic cross-sectional view of the stator 30. As shown in FIG. The stator 30 includes a stator core 31, a plurality of coils 35, a bearing holder 36, a bobbin 38, and a mold fixing portion 39. The stator 30 is annular in shape with a central axis J as its center.

[0030] The stator core 31 is made of a magnetic material that circulates magnetically. The stator core 31 has a yoke 32 and a plurality of teeth 33. The yoke 32 is disk-shaped and has a center on a central axis J along a plane perpendicular to the axial direction D. A through hole 31h is provided in the center of the yoke 32. A bearing holder 36 is fixed in the through hole 31h.

[0031] FIG. 4 is an exploded perspective view of the stator 30. As shown in FIG. The yoke 32 is a laminated core, and is formed by laminating thin electromagnetic steel sheets in the axial direction D. By stacking thin electromagnetic steel sheets with low conductivity, the yoke 32 can suppress the generation of eddy currents.

[0032] A mounting hole 32a recessed from the surface on the other axial side D2 toward the one axial side D1 is formed in the yoke 32. The mounting hole 32a may or may not penetrate the yoke 32 in the axial direction D, as shown in FIG.

[0033] As shown in Figure 2, the yoke 32 has a plurality of fixing holes 32h arranged in the circumferential direction C. The fixing holes 32h penetrate the yoke 32 in the axial direction D. Fixing screws 34 are inserted into the fixing holes 32h. The fixing screws 34 are also inserted into threaded holes 3f provided in the bottom 3e of the water receiving tub 3. This fixes the stator core 31 to the surface of the bottom 3e of the water receiving tub 3 facing the other axial side D2.

[0034] FIG. 5 is a diagram showing the stator 30 as viewed from the axial direction D. The teeth 33 protrude toward the other axial side D2 from a surface (also referred to as a first surface) facing the other axial side D2 of the yoke 32. The teeth 33 are arranged at equal intervals along the circumferential direction C of the central axis J.

[0035] The teeth 33 are laminated cores, and are formed by laminating thin electromagnetic steel sheets in the radial direction R. The teeth 33 are separate from the yoke 32, and are attached by press-fitting or the like into mounting holes 32a formed in the yoke 32. The lamination direction of the teeth 33 is not limited to the radial direction R, as long as it is different from the axial direction D, which is the lamination direction of the yoke 32.

[0036] The coils 35 are wound around the outer periphery of the teeth 33 via bobbins 38. The coils 35 are attached to the multiple teeth 33, respectively. The multiple coils 35 are arranged along the circumferential direction C. Ends of the coils 35 are drawn out from the stator 30 and connected to a power supply. This allows current to flow through the coils 35. Each coil 35 is wound around an axis parallel to the central axis J. Therefore, as shown in FIG. 3 , when a current flows through the coils 35, the coils 35 form magnetic poles in the axial direction D. In other words, the coils 35 form magnetic poles on the rotor 20 side that faces the axial direction D. Note that an insulating film may be sandwiched between the teeth 33 and the coils 35. This can prevent current from flowing from the coils 35 to the teeth 33 and the yoke 32.

[0037] The teeth 33 are formed by stacking in the radial direction R. Therefore, compared to teeth formed by stacking in the axial direction D, the teeth 33 allow the magnetic flux of the magnetic poles formed in the axial direction D to pass through more easily, as shown in FIG. 3, and the magnetic flux density can be easily increased.

[0038] The bobbin 38 may be separated for each tooth 33. The divided bobbins 38 have a higher strength than the bobbin 38 that is not divided.

[0039] For example, the coil 35 is attached to the stator core 31 as follows: First, the bobbin 38 around which the coil 35 is wound is attached to the tooth 33. Next, the tooth 33 to which the bobbin 38 is attached is attached to the yoke 32. Attaching the coil 35 in this manner makes it easier to arrange the coil 35 near the stator core 31, which makes it easier to improve the efficiency of the motor 10.

[0040] The bearing holder 36 has a cylindrical shape centered on the central axis line J. The bearing holder 36 holds the bearing 5p on its inner circumferential surface. The bearing holder 36 is fixed to the through hole 31h of the stator core 31.

[0041] The mold fixing portion 39 is a resin mold made of an insulating resin material. The mold fixing portion 39 is formed by molding the yoke 32, the teeth 33, and the bobbin 38 with resin. As a result, the yoke 32, the teeth 33, and the bobbin 38 are integrally molded by the mold fixing portion 39.

[0042] FIG. 6 is a cross-sectional view of a tooth 33A, which is a modified example of the tooth 33. As shown in FIG. The opposing surfaces 33b of the teeth 33A that face the magnets 24 of the rotor 20 have a larger cross-sectional area perpendicular to the axial direction D than other parts of the teeth 33A. The teeth 33A are formed in a generally conical shape such that the cross-sectional area perpendicular to the axial direction D increases the closer they are to the magnets 24 of the rotor 20. By increasing the area of ​​the opposing surfaces 33b that face the magnets 24, the efficiency of the motor 10 can be improved.

[0043] FIG. 7 is a cross-sectional view of a tooth 33B, which is a modification of the tooth 33. As shown in FIG. The opposing surfaces 33b of the teeth 33B that face the magnets 24 of the rotor 20 have a larger cross-sectional area perpendicular to the axial direction D than other parts of the teeth 33B. The outer diameter L1 of the opposing surfaces 33b of the teeth 33B that face the magnets 24 is larger than the inner diameter L2 of the bobbin 38. By increasing the area of ​​the opposing surfaces 33b that face the magnets 24, the efficiency of the motor 10 can be improved.

[0044] FIG. 8 is a cross-sectional view of a tooth 33C, which is a modified example of the tooth 33. As shown in FIG. The outer diameter L3 of the portion of the tooth 33C that is inserted into the mounting hole 32a of the yoke 32 is smaller than the inner diameter L2 of the bobbin 38. Positioning of the tooth 33C in the axial direction D is easy.

[0045] FIG. 9 is a cross-sectional view of a stator core 31A which is a modified example of the stator core 31. As shown in FIG. The stator core 31A has a third core 37 in addition to the yoke 32 and the multiple teeth 33C. The third core 37 is separate from the yoke 32 and the multiple teeth 33C and is made of a magnetic material that circulates magnetically. The third core 37 is formed in a cylindrical shape and is disposed between the teeth 33C and the bobbin 38 (coil 35). The inclusion of the third core 37 in the stator core 31A makes it easy to configure teeth 33 with a large area of ​​the opposing surface 33b, for example, as shown in FIGS. 6 and 7.

[0046] FIG. 10 is a cross-sectional view of a tooth 33D, which is a modification of the tooth 33. As shown in FIG. The teeth 33D have retainers 33c that prevent them from coming out of the mounting holes 32a. The maximum outer diameter L4 of the retainer 33c is larger than the inner diameter L3 of the mounting holes 32a. For example, the retainers 33c are formed by processing the tips of the teeth 33D that are inserted through the mounting holes 32a to increase the outer diameter. The retainers 33c prevent the teeth 33D from coming out of the mounting holes 32a and also make it easier to position the teeth 33D in the axial direction D.

[0047] FIG. 11 is a cross-sectional view of the tooth 33C fixed by the caulking 33r. The teeth 33C may be fixed to the yoke 32 by caulking the tip portions of the teeth 33C that are inserted into the attachment holes 32a with caulking pieces 33r.

[0048] FIG. 12 is a diagram showing a yoke 32A which is a modified example of the yoke 32. As shown in FIG. The yoke 32A is divided into individual teeth 33. This facilitates the work of attaching the teeth 33 to the yoke 32A. The divided yoke 32A is fixed by a mold fixing portion 39, as shown in FIG.

[0049] FIG. 13 is a diagram showing a yoke 32B which is a modified example of the yoke 32. As shown in FIG. The yoke 32B has a first surface 32s on the other axial side D2 to which the teeth 33C are attached, and a second surface 32t on the one axial side D1 opposite the first surface 32s. The yoke 32B has through holes 32u penetrating from the first surface 32s to the second surface 32t. The through holes 32u penetrate the yoke 32 in the axial direction D. The mold fixing portions 39 are formed by molding the first surface 32s and the second surface 32t with resin that passes through the through holes 32u. As a result, the first surface 32s and the second surface 32t to which the teeth 33C and the bobbins 38 are attached are integrally molded by the mold fixing portions 39. By resin-molding the first surface 32s and the second surface 32t together, fixation by, for example, crimping 33r can be strengthened, making it easy to fix the teeth 33C to the yoke 32B.

[0050] FIG. 14 is a diagram showing the through-hole 32u. The through holes 32u may be formed in any part of the yoke 32B. The number of through holes 32u is not limited. The shape of the through holes 32u may be round or polygonal when viewed from the axial direction D. The through holes 32u may be blind holes. It is desirable that the through holes 32u are arranged in positions that do not obstruct the return path of the magnetic flux. If the yoke 32B is divided like the yoke 32A, the through holes 32u may be formed in the divided parts 32v.

[0051] At least one of the embodiments described above can provide a highly efficient motor 10. The teeth 33 and the like are formed by stacking in the radial direction R. Therefore, compared to teeth formed by stacking in the axial direction D, the teeth 33 and the like more easily pass the magnetic flux of the magnetic poles formed in the axial direction D as shown in FIG. 3 , and the magnetic flux density can be easily increased.

[0052] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0053] 1... washing machine, 11... housing, 10... motor, 17... shaft, 20... rotor (rotor), 23... core, 24... rotor magnet, 30... stator (stator)

Claims

1. a rotor that rotates around a rotation axis; a stator facing the rotor across a gap in the axial direction of the rotary shaft; Equipped with the rotor has a magnet whose magnetic pole direction is in the axial direction, The stator includes: a starter core formed of a magnetic material that undergoes magnetic circulation; a coil that forms a magnetic pole in the axial direction; and The starter core is formed by combining teeth around which the coil is wound and a yoke separate from the teeth. Motor.

2. The teeth and the yoke are laminated cores. The motor according to claim 1 .

3. The stacking direction of the teeth is different from the stacking direction of the yoke. The motor according to claim 2 .

4. The teeth are stacked in a radial direction, The yoke is formed by stacking in the axial direction. The motor according to claim 2 .

5. The yoke is formed with a mounting hole recessed in the axial direction, The teeth are attached to the attachment holes. The motor according to claim 1 .

6. The mounting hole penetrates the yoke in the axial direction. The motor according to claim 5.

7. The teeth have retainers that prevent the teeth from coming out of the mounting holes. The motor according to claim 6.

8. The portions of the teeth inserted into the mounting holes are fixed to the yoke by caulking. The motor according to claim 6.

9. A plurality of the teeth are attached to the yoke, The bobbin around which the coil is wound is attached to the outer periphery of the teeth, The bobbin is separated for each of the teeth. The motor according to claim 1 .

10. a portion of the tooth facing the rotor has a larger surface area perpendicular to the axial direction than other portions of the tooth; The motor according to claim 1 .

11. a bobbin around which the coil is wound is attached to the teeth; an outer diameter of a portion of the tooth that is inserted into the mounting hole of the yoke is smaller than an inner diameter of the bobbin; The motor according to claim 5.

12. The third core is disposed between the teeth and the coil and is made of a magnetic material that magnetically circulates. The motor according to claim 1 .

13. A plurality of the teeth are attached to the yoke, The yoke is divided into individual teeth. The motor according to claim 1 .

14. The teeth and the yoke are integrally molded by resin molding. The motor according to claim 1 .

15. a first surface of the yoke to which the teeth are attached and a second surface opposite to the first surface are integrally molded by resin molding; The motor according to claim 1 .

16. The yoke has a through hole that penetrates in the axial direction and through which the resin is inserted.

16. The motor of claim 15.

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