Motor

Abstract

To provide a thin motor.SOLUTION: A motor 1 comprises: a rotor 3 that can rotate about a center axis CA extending in an axial direction; a stator 4 that includes a plurality of coil parts 45 are arranged in a circumferential direction; and a bus bar unit 10 having a bus bar 11 electrically connecting of ends 49 of each coil part 45 to each other. In the rotor 3, a rotor concave part concaved in the axial direction is formed, and at least part of the bus bar 11 is housed in the rotor concave part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motor. [Background technology]

[0002] Conventionally, it is known to use a bus bar to electrically connect the lead wires of the coils wound around each tooth of a motor, or to connect the lead wires of the coils to an external power source. For example, in Patent Document 1, a bus bar is connected to the lead wires (winding ends) of the coils. This bus bar is used as an external input terminal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special table 2008-146502 Summary of the Invention [Problem to be solved by the invention]

[0004] In the motor disclosed in Fig. 1 of Patent Document 1, the coil lead wires are connected to the bus bar in a state where they are drawn out to the upper side of Fig. 1, that is, in a direction away from the rotor in the up-down direction. This makes the motor larger in the axial direction.

[0005] The present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a thin motor. [Means for solving the problem]

[0006] An exemplary motor of the present invention is a motor including a rotor rotatable around a central axis extending in the axial direction, a stator having a plurality of coil portions arranged in the circumferential direction, and a bus bar unit including a bus bar electrically connecting the ends of the coil portions, wherein a rotor recess that is recessed in the axial direction is formed in the rotor, and at least a portion of the bus bar is accommodated in the rotor recess. Effect of the Invention

[0007] According to the present invention, a thin motor can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a schematic diagram of a motor. [Diagram 2] FIG. 2 is a plan view illustrating a schematic diagram of the bus bar unit. [Diagram 3] FIG. 3 is a side view diagrammatically illustrating the bus bar unit. [Figure 4] FIG. 4 is a diagram showing a schematic diagram of the connection relationship between each tooth, each coil portion, and each bus bar in the motor. [Diagram 5] FIG. 5 is a cross-sectional view showing a schematic diagram of a motor according to a modified example, and is an enlarged view showing the periphery of a bus bar unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Exemplary embodiments of the present invention will now be described with reference to the drawings.

[0010] First, in this specification, the rotating shaft of the motor 1 is called the central axis CA, and the direction parallel to the central axis CA is called the "axial direction". In addition, one side of the axial direction from the lower bearing 7 to the upper bearing 6 is called the "axial upper direction", and the other side of the axial direction from the upper bearing 6 to the lower bearing 7 is called the "axial lower direction". In the surface of each component, the surface facing the axial upper direction is called the "upper surface", and the surface facing the axial lower direction is called the "lower surface". In addition, in each component, the end in the axial direction is called the "axial end", and the position of the end in the axial direction is called the "axial end". In particular, the end in the axial upper direction is called the "axial upper end", and the position of the end in the axial upper direction is called the "axial upper end". Furthermore, the end in the axial lower direction is called the "axial lower end", and the position of the end in the axial lower direction is called the "axial lower end".

[0011] In addition, the direction in which a straight line perpendicular to the central axis CA extends is called the "radial direction". In addition, one radial direction toward the central axis CA is called the "radial inner direction", and the other radial direction away from the central axis CA is called the "radial outer direction". In the side of each component, the side facing the radial direction is called the "radial side". In particular, the side facing the radially inward direction is called the "radial inner side", and the side facing the radially outward direction is called the "radial outer side". In addition, in each component, the end in the radial direction is called the "radial end", and the position of the end in the radial direction is called the "radial end". In particular, the end in the radially inward direction is called the "radial inner end", and the position of the end in the radially inward direction is called the "radial inner end". In addition, the end in the radially outward direction is called the "radial outer end", and the position of the end in the radially outward direction is called the "radial outer end".

[0012] The rotation direction around the central axis CA is called the "circumferential direction". The counterclockwise direction with respect to the central axis CA as viewed from above in the axial direction is called the "one circumferential direction Rd1", and the clockwise direction with respect to the central axis CA as viewed from above in the axial direction is called the "other circumferential direction Rd2". The side surface of each component facing the circumferential direction is called the "circumferential side surface". The end portion of each component in the circumferential direction is called the "circumferential end portion", and the position of the end portion in the circumferential direction is called the "circumferential end". In particular, the end portion in the one circumferential direction Rd1 is called the "one circumferential end portion", and the position of the end portion in the one circumferential direction Rd1 is called the "one circumferential end". Furthermore, the end portion in the other circumferential direction Rd2 is called the "other circumferential end portion", and the position of the end portion in the other circumferential direction Rd2 is called the "other circumferential end".

[0013] The above-described designations of directions, faces, ends, and their positions do not indicate the positional relationships and directions when incorporated into an actual device. Hereinafter, exemplary embodiments will be described with reference to the drawings.

[0014] <Embodiment> The motor 1 is a brushless motor that is driven by a three-phase AC current consisting of phases U, V, and W. The motor 1 according to this embodiment is a so-called inner rotor type motor in which a rotor rotates inside a substantially annular stator.

[0015] The motor 1 described below can be applied to any device that can use a motor, such as a ceiling fan. It can also be installed in a motor that needs to be thin, such as the joints of a robot arm.

[0016] 1 is a cross-sectional view showing a motor 1 according to an embodiment of the present invention. The motor 1 includes a shaft 2, a rotor 3, a stator 4, a casing 5, and a bus bar unit 10, as shown in FIG.

[0017] The casing 5 is a case-like part that houses the rotor 3 and the stator 4. The casing 5 is formed in a cylindrical shape that is slightly thin in the axial direction and has a space inside. The casing 5 has an upper wall portion 5a that is substantially circular when viewed from above in the axial direction, a peripheral wall portion 5b that is substantially cylindrical, and a lower wall portion 5c that is substantially circular when viewed from below in the axial direction. In the example shown in FIG. 1, the casing 5 is illustrated as an integrated member, but this is not limited thereto. For example, the upper wall portion 5a, the peripheral wall portion 5b, and the lower wall portion 5c may be formed as separate members, and these may be fixed to each other by screws or the like.

[0018] A through hole is formed in the upper wall portion 5a of the casing 5 at a central portion when viewed from above in the axial direction, and the shaft 2 is inserted and fixed through this through hole via an upper bearing 6. A through hole is formed in the lower wall portion 5c of the casing 5 at a central portion when viewed from below in the axial direction, and the shaft 2 is inserted and fixed through this through hole via a lower bearing 7. This allows the shaft 2 to be held rotatably relative to the casing 5.

[0019] The shaft 2 extends in the axial direction around the central axis CA, and in this embodiment, is rotatable together with the rotor 1 around the central axis CA. In other words, the shaft 2 is the rotating shaft of the motor 1. The shaft 2 is rotatably supported with respect to the case 5 by an upper bearing 6 and a lower bearing 7. In this embodiment, the upper bearing 6 and the lower bearing 7 are ball bearings, but are not limited thereto and may be other types of bearings.

[0020] The rotor 3 is rotatable about a central axis CA extending in the axial direction. The motor 1 includes the rotor 3. As shown in Fig. 1, the rotor 3 includes a rotor bushing 31, a rotor core 37, and a plurality of magnets 38.

[0021] The rotor bush 31 is a member formed by, for example, die casting. The rotor bush 31 has a disk portion 32 and a cylindrical portion 33, which are integrally formed from a single material.

[0022] The disk portion 32 is a disk-shaped portion having a thickness in the axial direction. A through hole 32a is formed in the center of the disk portion, and the shaft 2 is inserted and fixed in the through hole 32a via a tolerance ring 8, which will be described in detail later.

[0023] The cylindrical portion 33 is a generally cylindrical portion extending in the up-down direction. The inner peripheral surface of the cylindrical portion 33 is fixed integrally with the outer peripheral surface of the disk portion 32. The axial length of the cylindrical portion 33 is longer than the axial length of the disk portion. The disk portion 32 is located slightly above the axial center of the cylindrical portion 33.

[0024] As shown in FIG. 1, a rotor recess 34 is provided in a portion of the rotor bush 31 below the disk portion 32. The rotor recess 34 is a portion surrounded by the lower surface of the disk portion 32 and the inner circumferential surface of the cylindrical portion. As a result, the internal space of the rotor recess 34 is formed to be approximately cylindrical. The rotor recess 34 is recessed axially upward. As a result, the rotor recess 34 opens axially downward. The motor recess 34 accommodates an upper portion of the bus bar unit 10, which will be described in detail later.

[0025] The rotor core 37 is a cylindrical portion that comes into contact with the outer peripheral surface of the cylindrical portion 33 of the rotor bush 31. The rotor core 37 of this embodiment is formed by stacking thin, annular electromagnetic steel sheets in the axial direction.

[0026] In this embodiment, sixteen magnets 38 are provided. The magnets 38 are arranged and fixed to the outer circumferential surface of the rotor core 37 in the circumferential direction such that different magnetic poles (i.e., S poles and N poles) face outward alternately in the circumferential direction. For example, the magnets 38 are fixed to the rotor core 37 by an adhesive.

[0027] The rotor 3 is fixed to the shaft 1 by a tolerance ring 8. The tolerance ring 8 is a substantially cylindrical member made of metal and has spring properties in the radial direction. In this embodiment, the shaft 1 is inserted into the inner peripheral surface of the tolerance ring 8, and the outer peripheral surface of the tolerance ring 8 is inserted into the inner peripheral surface of the through hole of the rotor bush 31. As a result, the tolerance ring 8 is compressed in the radial direction between the shaft 2 and the rotor 3, and the shaft 2 and the rotor 3 are firmly fixed together by the repulsive force.

[0028] The stator 4 is formed in a generally annular shape so as to radially surround the rotor 1 from the outside. The stator 4 includes a stator core 41, a plurality of coil portions 45, and a bus bar unit .

[0029] The stator core 41 is a substantially annular magnetic body, and is arranged so as to surround the rotor from the radial outside. In this embodiment, the stator core 41 is formed by stacking electromagnetic steel sheets having a thickness in the axial direction in the axial direction. The stator core 41 has an annular core back 42 and a plurality of teeth 43 (12 in this embodiment) protruding radially inward from the inner peripheral surface of the core back 42. The plurality of teeth 43 are arranged at equal intervals in the circumferential direction.

[0030] The coil portions 45 each include a coil main body portion 46 that is wound around each tooth 43, a crossover portion 47 that connects the main body portions 46 together, and a lead-out portion 48 that extends away from the coil main body portion 46 and has a tip portion (coil end portion 49) that is electrically connected to the bus bar unit 10. As a result, the coil portions 45 are arranged in the circumferential direction.

[0031] Fig. 2 is a plan view that typically shows the bus bar unit 10. Fig. 3 is a side view that typically shows the bus bar unit 10.

[0032] The busbar unit 10 is a component for electrically connecting the coil portions 22 arranged at a distance in the circumferential direction to each other. The busbar unit 10 includes a plurality of busbars 11 (six in this embodiment) and a busbar holding portion 16. In the busbar unit 10 according to this embodiment, the plurality of busbars 11 formed by press working are fixed in position relative to each other by the busbar holding portion 16 integrally molded from a resin material.

[0033] The busbar 11 comprises a pair of busbar end portions 12 and a busbar main body 13. In Fig. 3, the busbar main body 13 embedded in the busbar holding portion 16 is shown by a dashed line, which is a schematic representation of the shape of the busbar main body 13. The busbar main bodies 13 may have any shape as long as they do not come into contact with each other when assembled into the busbar unit 10.

[0034] The bus bar end 12 is a portion that protrudes radially outward from the bus bar holding portion 16 and is exposed to the outside. The bus bar end 12 is formed in a J shape when viewed from above, and the coil end 49 of the lead-out portion 48 is sandwiched in this portion and connected by soldering, welding, or the like.

[0035] In the busbar unit 10 according to this embodiment, twelve busbar ends 12 are arranged at equal intervals in the circumferential direction. That is, the busbar ends 12 are arranged at intervals of 30 degrees. A pair of busbar ends 12 in one busbar 11 are provided at positions 180 degrees apart from each other, and are connected by a busbar body 13.

[0036] The busbar main body 13 is a portion embedded inside the busbar holding portion 16. Busbar ends 12 are provided from both ends of each busbar main body 13 so as to extend circumferentially outward beyond the busbar holding portion 16.

[0037] The busbar holding portion 16 is a member made of a resin material. The busbar holding portion 16 is substantially cylindrical, with a holding portion through hole 16a formed through the center portion. The busbar main body 13 is embedded inside the busbar holding portion 16. The busbar unit 10 is fixed to the bottom wall portion 5c of the casing 5 so that the holding portion through hole 16a is coaxial with the shaft 2. The busbar unit may be fixed to the stator core.

[0038] In the busbar unit 10, the busbar bodies 13 of the busbars 11 are provided in the busbar holding portion 16 so as not to come into contact with each other. Specifically, for example, the busbar bodies 13 are arranged at intervals in the axial and radial directions so as not to come into contact with each other. Note that in Fig. 3, the busbar ends 12 have the same axial height, but this is not limited thereto and the axial heights of the busbar ends 12 may be different. This makes it possible to prevent the busbars 11 from coming into contact with each other.

[0039] Fig. 4 is a diagram showing a schematic diagram of the connection relationship between each tooth 43, each coil portion 45, and each bus bar 11 in the motor 1 according to this embodiment. For ease of explanation, in Fig. 4, the arrangement direction of the teeth 43 is shown as a straight line. Also, in Fig. 4, for ease of explanation, some symbols have alphabets (a, b, c, ...) added to the end. Hereinafter, when describing each component with distinction, symbols with alphabets added to the end are used, and when describing without distinction, symbols with only numbers are used.

[0040] In this embodiment, the multiple coil parts 45 have coil parts through which a U-phase current flows, coil parts through which a V-phase current flows, and coil parts through which a W-phase current flows. In the example shown in Fig. 4, a U-phase current flows through the coil main parts 46a, 46b, 46g, and 46h, a V-phase current flows through the coil parts 46c, 46d, 46i, and 46j, and a W-phase current flows through the coil parts 46e, 46f, 46k, and 46l. The number of coil main parts 46 for each phase is not limited to the example shown in Fig. 4.

[0041] In this embodiment, the coil main body parts 46 of each phase adjacent in the circumferential direction are connected by a crossover part 47. Specifically, for the U phase, the coil main body parts 46a and 46b are connected by a crossover part 47ab, and the coil main body parts 46g and 46h are connected by a crossover part 47gh. For the V phase, the coil main body parts 46c and 46d are connected by a crossover part 47cd, and the coil main body parts 46i and 46j are connected by a crossover part 47ij. For the W phase, the coil main body parts 46e and 46f are connected by a crossover part 47ef, and the coil main body parts 46k and 46l are connected by a crossover part 47kl. The coil main body parts and the crossover part may be formed of a series of coils, or the ends of the coil main bodies may be connected to each other by a crossover part formed of a different coil wire.

[0042] In this embodiment, the lead-out portions of each phase that are spaced apart in the circumferential direction are connected to each other by each bus bar 11. Specifically, for the U phase, lead-out portion 48b and lead-out portion 48g are connected by bus bar 11bg, and lead-out portion 48h and lead-out portion 48a are connected by bus bar 11ha. For the V phase, lead-out portion 48d and lead-out portion 48i are connected by bus bar 11di, and lead-out portion 48j and lead-out portion 48c are connected by bus bar 11jc. For the W phase, lead-out portion 48f and lead-out portion 48k are connected by bus bar 11fk, and lead-out portion 48l and lead-out portion 48e are connected by bus bar 11le.

[0043] <Effects> 1, in this embodiment, the busbar unit 10 is arranged so that at least a portion of it is housed inside the rotor recess 34. Specifically, in this embodiment, an upper portion of the busbar unit 10 is housed inside the rotor recess 34. This makes it possible to reduce the axial height of the motor 1 compared to, for example, a case in which the busbar unit is arranged below the lower end surface of the rotor. In other words, the motor 1 can be made thinner.

[0044] In this embodiment, the coil end 49, which is the tip of the lead-out portion 48, is housed inside the rotor recess 34. This eliminates the need to extend the bus bar end outside the rotor recess, allowing the length of the bus bar to be shortened.

[0045] Furthermore, in this embodiment, the bus bar holding portion 16 is made of a resin material and is molded integrally with the bus bar 11. This makes it possible to omit an assembly process such as assembling the bus bar to the bus bar holding portion, thereby simplifying the assembly process of the motor.

[0046] Moreover, in this embodiment, the bus bar unit 10 is disposed between the upper bearing 6 and the lower bearing 7. This allows the motor 1 to be made thinner.

[0047] In this embodiment, a tolerance ring 8 is used to connect the shaft 2 and the rotor 3. This allows the shaft 2 and the rotor 3 to be fixed more firmly than when they are simply fixed with an adhesive. Furthermore, as shown in FIG. 1, the tolerance ring 8 has approximately the same axial length as the disc portion 32 of the rotor bushing 31. This allows sufficient space to be secured for the rotor recess 34, thereby ensuring the arrangement space for the bus bar unit 10.

[0048] <2. Modifications> FIG. 5 is a cross-sectional view showing a schematic diagram of a motor 1a according to a modified example, and is an enlarged view showing the periphery of a bus bar unit 10. As shown in FIG.

[0049] In the above embodiment, an example has been described in which the lower bearing 7 is fixed to the lower wall portion 5c of the casing 5, but this is not limiting. Specifically, the lower bearing 7 may be held by a member for fixing a bearing that is fixed to the casing 5 (bearing holder 9 in this modified example).

[0050] The bearing holder 9 is formed into a cylindrical shape using, for example, a metal member. The bearing holder 9 is fixed to the lower wall 5c of the casing 5 by, for example, screwing so that its central axis is coaxial with the shaft 2. The outer ring of the lower bearing 7 is fixed to the inner circumferential surface of the bearing holder 9. The bearing holder 9 may also be fixed by, for example, an adhesive.

[0051] 5, in this modification, the bearing holder 9 is housed inside the holder through hole 16a of the busbar holder 16. That is, at least a part of the bearing holder 9 is disposed in the holder through hole 16a. This allows the busbar unit 10 and the bearing holder 9 to be disposed so as to overlap when viewed from the radial outside, thereby making it possible to reduce the thickness of the motor.

[0052] <3.Other> The embodiments of the present invention have been described above. Note that the scope of the present invention is not limited to the above-described embodiments. The present invention can be implemented by adding various modifications to the above-described embodiments without departing from the spirit of the invention. Furthermore, the matters described in the above-described embodiments can be appropriately combined in any manner as long as no contradiction occurs.

[0053] In this embodiment, the motor is driven by a three-phase AC current, but is not limited to this example, and the motor may be driven by a single-phase AC current.

[0054] In this embodiment, a motor in which a circuit board for controlling the drive of the motor is not provided inside the casing has been described as an example, but the present invention can also be applied to a motor in which a circuit board is provided inside the casing.

[0055] In the present embodiment, an example has been described in which two coil main bodies 46 that are circumferentially separated from each other (in other words, two coil main bodies 46 that sandwich one or more coil parts in the circumferential direction) are all electrically connected by the bus bar 11, but this is not limiting. Specifically, as long as at least a portion of the bus bar is housed within the rotor recess 34, there may be any number of such bus bars.

[0056] In the present embodiment, the busbar holding portion has been described as being integrally molded with the busbar, but this is not limiting. For example, a busbar holding portion having a groove capable of accommodating the busbar may be formed by resin molding or the like, and the busbar may be fitted into the busbar holding portion to form a busbar unit.

[0057] <4. Summary> The embodiments described thus far will be summarized below.

[0058] a rotor rotatable about a central axis extending in an axial direction; a stator having a plurality of coil portions arranged in a circumferential direction; a bus bar electrically connecting ends of the coil portions to each other; A motor comprising: The rotor is formed with a rotor recess that is recessed in the axial direction, At least a portion of the bus bar is configured to be housed in the rotor recess (first configuration).

[0059] The motor of the first configuration is as follows: The end of the coil portion may be configured to be housed within the rotor recess (second configuration).

[0060] In addition, the motor of the first or second configuration is A plurality of the bus bars; a bus bar holding portion that holds a plurality of the bus bars, The bus bar holding portion may be configured (third configuration) to be formed of a resin material and integrally molded with the plurality of bus bars.

[0061] The motor of the third configuration is a shaft that is inserted through and fixed to a central axis of the rotor and rotates together with the rotor; A pair of bearings that rotatably support the shaft, a bus bar holding portion having a through hole axially penetrating the bus bar holding portion; At least a part of a bearing holder that holds one of the pair of bearings may be disposed in the holder through hole (fourth configuration).

[0062] In addition, the motor having any one of the first to fourth configurations is The bus bar unit may be arranged between the pair of bearings in the axial direction (fifth configuration).

[0063] Moreover, the motor of the fourth or fifth configuration is The sixth configuration may further include a tolerance ring that is disposed between the rotor and the shaft and connects the rotor and the shaft. [Industrial Applicability]

[0064] The present invention is useful for motors having bus bars. [Explanation of symbols]

[0065] Explanation of the Reference Signs 1...motor, 2...shaft, 3...rotor, 4...stator, 5...casing, 6...upper bearing, 7...lower bearing, 8...tolerance ring, 9...bearing holder, 10...busbar unit, 11...busbar, 12...busbar end, 13...busbar main body, 16...busbar holder, 31...rotor bushing, 32...disc portion, 32a...through hole, 33...cylindrical portion, 34...rotor recess, 37...rotor core, 38...magnet, 41...stator core, 42...core back, 43...teeth, 45...coil portion, 46...coil main body, 47...crossover portion, 48...lead portion, 49...coil end, CA...central axis

Claims

1. a rotor rotatable about a central axis extending in an axial direction; a stator having a plurality of coil portions arranged in a circumferential direction; a bus bar unit including a bus bar that electrically connects ends of the coil portions to each other; A motor comprising: The rotor is formed with a rotor recess that is recessed in the axial direction, At least a portion of the bus bar is received in the rotor recess.

2. The motor of claim 1 , wherein an end of the coil portion is received within the rotor recess.

3. The bus bar unit includes: A plurality of the bus bars; a bus bar holding portion that holds a plurality of the bus bars, The motor according to claim 2 , wherein the bus bar holding portion is made of a resin material and is integrally molded with the plurality of bus bars.

4. a shaft that is inserted through and fixed to a central axis of the rotor and rotates together with the rotor; A pair of bearings that rotatably support the shaft, a bus bar holding portion having a through hole axially penetrating the bus bar holding portion; The motor according to claim 3 , wherein at least a part of a bearing holder that holds one of the pair of bearings is disposed in the holder through hole.

5. The motor according to claim 4 , wherein the bus bar unit is disposed axially between the pair of bearings.

6. The motor according to claim 4 or 5, further comprising a tolerance ring disposed between the rotor and the shaft and connecting the rotor and the shaft.

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