motor

Abstract

To provide a motor that can be miniaturized. [Solution] The motor 1 comprises a busbar 30 having terminals 35 that are electrically connected to an external device, and a stator 20, wherein the terminals 35 of the busbar 30 are located inside the stator 20.

Description

Technical Field

[0001] The present invention relates to a motor.

Background Art

[0002] Patent Document 1 discloses a motor having a bus bar for supplying current to a plurality of coils of a stator. Terminals for supplying current from an external power source to the bus bar are connected to each of the bus bars.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The terminals of the bus bar extend axially above the stator, that is, the coil. Therefore, in this motor, it is necessary to secure a placement space for the terminals axially. The dimensions of the motor increase by the amount of the placement space.

[0005] One of the problems of the present invention is to provide a motor that can achieve miniaturization.

Means for Solving the Problems

[0006] A motor according to an aspect of the present invention includes a bus bar having terminals electrically connected to an external device, and a stator, wherein the terminals of the bus bar are inside the stator.

Brief Description of the Drawings

[0007] [Figure 1] It is a perspective view schematically showing the structure of a motor 1 according to a first embodiment of the present invention. [Figure 2]This is a cross-sectional view along line 2-2 in Figure 1. [Figure 3] This is a cross-sectional view along line 3-3 in Figure 2. [Figure 4] This is a perspective view showing a schematic structure of a divided core 24 and a divided insulator 25 in one specific example. [Figure 5] This is a perspective view showing a schematic structure of a bus bar 30 in one specific example. [Figure 6] This is a perspective view showing a schematic structure of a bus bar 30 in one specific example. [Figure 7] This is an exploded perspective view showing a schematic representation of the structure of a busbar 30 in one specific example. [Figure 8] This is an exploded perspective view schematically showing the structure of the motor 1 according to the first embodiment of the present invention. [Figure 9] This is a schematic plan view showing the structure of a motor 1 according to the first embodiment of the present invention. [Figure 10] This is a schematic perspective view showing the structure of motor 1A according to a second embodiment of the present invention. [Figure 11] This is a partially exploded perspective view schematically showing the structure of motor 1A according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0008] One embodiment of the present invention will be described below with reference to the attached drawings. Figure 1 is a schematic perspective view showing the structure of a motor 1 according to the first embodiment of the present invention. Figure 2 is a cross-sectional view along line 2-2 in Figure 1. Referring together to Figures 1 and 2, the housing is not shown in this motor 1. The motor 1 has, for example, a cylindrical shaft 10 with axis x as its central axis. In the following description, the direction along this axis x will be defined as the axial direction. The shaft 10 is supported in the housing so as to be rotatable about axis x by, for example, two bearings (not shown) arranged in the axial direction.

[0009] In the following explanation, one side in the axial direction is defined as the upper side, and the other side as the lower side. These upper and lower sides defined in the axial direction do not necessarily coincide with the up and down relationship in the direction of gravity. Furthermore, the radial direction of motor 1 is defined perpendicular to axis x. In this radial direction, the side away from axis x is defined as the radial outer side (outer circumference), while the direction approaching axis x is defined as the radial inner side (inner circumference). In addition, the circumferential direction of motor 1 is defined around axis x.

[0010] As shown in Figure 2, a rotor 11 is fixed to the shaft 10. The rotor 11 has a rotor core 12 and a first magnet 13. The rotor core 12 is formed in a cylindrical shape, for example, with axis x as the center. The rotor core 12 is formed from a laminate of multiple magnetic materials stacked in the axial direction. The shaft 10 is fixed inside the rotor core 12, for example, by press-fitting. A cylindrical first magnet 13 is fixed to the outer circumferential surface of the rotor core 12. The first magnet 13 is, for example, a permanent magnet. In the first magnet 13, north poles and south poles are alternately set in the circumferential direction.

[0011] Figure 3 is a cross-sectional view along line 3-3 in Figure 2. Referring to Figures 1 to 3 together, a stator 20, which is, for example, cylindrical overall, is arranged opposite the rotor 11 on its outer circumference. The stator 20 has a stator core 21, an insulator 22, and a coil 23. The stator core 21 is fixed to the inner circumferential surface of the housing. The stator core 21 is formed from a laminate of magnetic material. The coil 23 is, for example, copper wire. The insulator 22 is formed from an insulating material such as a resin material. The insulator 22 insulates the stator core 21 and the coil 23 from each other.

[0012] As shown in Figure 3, the stator core 21 in this example is formed from 12 segmented cores 24. Each segmented core 24 has a portion 24a located on the outer circumference (hereinafter referred to as the "outer circumference portion") and teeth 24b extending inward from the outer circumference portion 24a. The outer circumference portion 24a and the teeth 24b are formed integrally with each other. By arranging multiple segmented cores 24 in the circumferential direction, multiple outer circumference portions 24a are continuous in the circumferential direction. The teeth 24b are also arranged at predetermined intervals (for example, equal intervals) in the circumferential direction. The inner surface of the magnetic pole portion 24c, which is the inner circumference portion of the teeth 24b, faces the outer circumference surface of the first magnet 13 with a predetermined magnetic gap.

[0013] The insulator 22, like the divided core 24, is formed from 12 divided insulators 25. Figure 4 is a schematic perspective view showing the structure of a divided core 24 and divided insulators 25 according to one specific example. As shown in Figure 4, one divided insulator 25 is attached to one divided core 24. The divided insulator 25 has, for example, an inner wall 25a, a cylinder 25b, and an outer wall 25c. The inner wall 25a and the outer wall 25c are joined to each other by the cylinder 25b. The inner wall 25a, cylinder 25b, and outer wall 25c are formed integrally with each other.

[0014] The inner wall 25a is formed from, for example, a frame. The inner wall 25a is positioned on the outer circumference side of the magnetic pole portion 24c of the divided core 24. Recesses 25d are formed at the top and bottom of the inner wall 25a, respectively. The recesses 25d are recessed from the upper or lower end surface and the inner circumference surface of the inner wall 25a, respectively. A cylinder 25b extends from the inner wall 25a outward. The cylinder 25b surrounds the teeth 24b. A coil 23 is wound around this cylinder 25b. An outer wall 25c is continuous with the outer circumference side of the cylinder 25b. The outer wall 25c is formed from, for example, a frame. The outer wall 25c is positioned on the inner circumference side of the outer circumference portion 24a of the divided core 24.

[0015] Returning to FIGS. 1 and 2, the motor 1 includes a bus bar 30 attached to the stator 20. In this example, the bus bar 30 is housed inside the generally cylindrical stator 20. The bus bar 30 is generally formed in a cylindrical shape around the axis x. The bus bar 30 has a housing 31 and one or more conductive members 32 housed in the housing 31. The housing 31 is formed of an insulating material including a resin material. The conductive member 32 is formed of a conductive material including a metallic material such as copper or aluminum.

[0016] FIGS. 5 and 6 are perspective views schematically showing the structure of the bus bar 30 according to one specific example. FIG. 7 is an exploded perspective view schematically showing the structure of the bus bar 30 according to one specific example. In this example, three conductive members 32 are laminated and housed axially in the housing 31. Each conductive member 32 has a main body 33 extending annularly around the axis x, one or more first terminals 34 protruding from the main body 33 to the outer peripheral side, and one second terminal 35 protruding axially upward from the main body 33. The main body 33, the first terminal 34, and the second terminal 35 are integrally formed from the aforementioned conductive material. The main body 33 is formed, for example, in a flat annular shape.

[0017] In this example, four first terminals 34 and one second terminal 35 are arranged at predetermined intervals (equal intervals in this example) in the circumferential direction. By shifting the positions of the first terminals 34 and the second terminal 35 in the circumferential direction with the three conductive members 32, twelve first terminals 34 and three second terminals 35 are arranged at predetermined intervals around the axis x. In this example, the axial position of the first terminal 34 with respect to the main body 33 is different for each conductive member 32. As a result, among the twelve first terminals 34 arranged shifted from each other in the circumferential direction, the axial positions of the first terminals 34, 34 adjacent to each other in the circumferential direction are different.

[0018] The first terminal 34 is, for example, a fork-shaped terminal extending radially outward. The lead wire of the coil 23 is electrically connected to each first terminal 34. That is, the first terminal 34 constitutes a portion electrically connected to the coil 23. Each lead wire may be joined to the first terminal 34 using a joining material (for example, solder). The second terminal 35 protrudes axially outward from an opening formed in the housing of the motor 1. The second terminal 35 is electrically connected to an external device (for example, a power source) by, for example, wiring or the like. In this way, current is supplied from the power source to the coil 23 via the bus bar 30.

[0019] An insulating member 36 is disposed between the conductive members 32, 32 adjacent in the axial direction. In this example, the insulating member 36 is formed from, for example, an annular member formed in a flat sheet shape. The insulating member 36 is formed from an insulating material containing, for example, a resin material. In a plan view from above, the contour of the insulating member 36 substantially coincides with the contour of the main body 33 of the conductive member 32 in a plan view from above. By the function of this insulating member 36, insulation between the conductive members 32, 32 adjacent in the axial direction can be established. In this way, in the housing 31, three conductive members 32 and two insulating members 36 are stacked axially.

[0020] The housing 31 of the bus bar 30 has a base 37 and a cover 38. The base 37 has a portion (hereinafter referred to as the "accommodating portion") 37a that accommodates the three conductive members 32, and three protruding portions 37b that protrude from the accommodating portion 37a to the outer peripheral side. The accommodating portion 37a forms an annular space for accommodating the three conductive members 32. A plurality of recesses 37c are formed in the side wall on the outer peripheral side of the accommodating portion 37a. When the conductive member 32 is accommodated in the accommodating portion 37a, the recesses 37c receive the first terminals 34 of the conductive member 32, respectively. The first terminal 34 protrudes to the outer peripheral side from the side wall on the outer peripheral side of the accommodating portion 37a.

[0021] The protrusions 37b are provided corresponding to the positions of each second terminal 35 of the conductive member 32. In this example, since the second terminals 35 of the three conductive members 32 are arranged at equal intervals around the axis x, the protrusions 37b are similarly arranged at equal intervals around the axis x. A convex portion 37d is formed on the lower surface of each protrusion 37b, projecting downward in the axial direction. In this example, the convex portion 37d is formed adjacent to the outer peripheral end of the protrusion 37b. That is, the convex portion 37d is formed from the outer peripheral end of the protrusion 37b toward the inner peripheral side.

[0022] The cover 38 has an annular portion (hereinafter referred to as the "annular portion") 38a and three protrusions 38b that project outward from the annular portion 38a. The annular portion 38a closes the annular space of the base 37 when the cover 38 is coupled to the base 37. The protrusions 38b are formed around the axis x corresponding to the position of the second terminal 35, i.e., the position of the convex portion 37d of the base 37. The protrusions 38b are supported on the protrusions 37b when the cover 38 is coupled to the base 37. The protrusions 38b are formed in a cylindrical shape capable of holding the second terminal 35 of the conductive member 32.

[0023] The busbar 30 has one or more sensors 40 fixed to the housing 31. The sensors 40 are fixed to the inner circumferential surface of a cylindrical member (hereinafter referred to as "cylindrical member") 41 whose central axis is axis x. In this example, three sensors 40 are arranged at predetermined intervals (for example, at equal intervals) in the circumferential direction. The cylindrical member 41 is fixed to the inner circumferential surface of the housing 31. In this example, the position of the sensors 40 in the circumferential direction corresponds to the position of the second terminal 35 in the circumferential direction. The sensors 40 are, for example, circuit boards on which Hall elements are mounted. A Hall element is a magnetic detection element that uses the Hall effect.

[0024] Figure 8 is an exploded perspective view schematically showing the structure of the motor 1 according to the first embodiment of the present invention. Figure 9 is a plan view schematically showing the structure of the motor 1 according to the first embodiment of the present invention. Referring together to Figures 2, 8 and 9, when attaching the stator 20 to the busbar 30, the protrusions 37d of the base 37 of the housing 31 of the busbar 30 are received in the recesses 25d at the top of the inner wall 25a of the insulator 22 of the stator 20. Specifically, each protrusion 37d fits into the recess 25d at the top of the inner wall 25a. In this way, the busbar 30 is attached to the stator 20. The protrusions 37d of the busbar 30 correspond to the parts supported by the insulator 22.

[0025] As shown in Figure 2, the upper end of the busbar 30, i.e., the housing 31, in the axial direction is located below the upper end of the stator 20, i.e., the coil 23, in the axial direction. However, the protruding portion 38b and the second terminal 35 of the cover 38 of the housing 31 protrude above the upper end of the coil 23. Furthermore, as shown in Figures 2 and 9, in the radial direction, the first terminal 34 and the second terminal 35 of the busbar 30 are located inside the stator 20, i.e., the coil 23. In addition, in the radial direction, the outer peripheral end (outer peripheral portion) of the first terminal 34 of the busbar 30 faces the inner peripheral surface (inner peripheral portion) of the stator 20, i.e., the coil 23.

[0026] In this example, for example, two lead wires (not shown) are drawn from coils 23, 23 wound around two circumferentially adjacent split cores 24, 24. In this way, twelve lead wires are drawn from twelve coils 23. Each drawn lead wire is electrically connected to a first terminal 34 of the busbar 30. Specifically, the lead wires are drawn, for example, from the bottom of the first terminal 34, through the fork-shaped terminals to the top. As mentioned above, a bonding material (e.g., solder) may be used for the connection to the first terminal 34. Alternatively, the first terminal 34 may be crimped to the lead wire by crimping the fork-shaped terminal portion.

[0027] On the other hand, the busbar 30 has a second magnet 14 fixed to the shaft 10. The second magnet 14 is, for example, a cylindrical permanent magnet with axis x as its central axis. The second magnet 14 has alternating north and south poles in the circumferential direction. The second magnet 14 is fixed to the outer circumferential surface of the shaft 10 above the rotor 11 in the axial direction. As shown in Figures 1, 2, and 9, when the busbar 30 is mounted on the stator 20, three sensors 40 face each other in the radial direction on the outer circumferential surface of the second magnet 14 with a predetermined gap between them.

[0028] Each sensor 40 is connected to wiring (not shown) that enables the output of changes in the voltage of the sensor 40 as a signal to an external device. As the shaft 10, i.e., the second magnet 14, rotates around axis x, the magnetic poles of the second magnet 14 facing the sensor 40 in the radial direction change. This change in magnetic poles causes a change in the voltage of the sensor 40. This change in voltage is detected and output as a signal to the external device, and the external device processes the received signal to detect the position of the magnetic poles of the second magnet 14 (in the circumferential direction). In this way, the rotational position of the shaft 10, i.e., the rotor 11, around axis x can be determined by the sensor 40.

[0029] In the motor 1 described above, the busbar 30 is positioned inside the stator 20. Specifically, the housing 31 of the busbar 30 is positioned below the upper end of the coil 23 of the stator 20, and the outer peripheral end of the first terminal 34 of the busbar 30 faces the inner peripheral surface of the coil 23 of the stator 20. Furthermore, the second terminal 35 is positioned inside the coil 23 of the stator 20 in the radial direction and extends upward in the axial direction. Therefore, since the busbar 30 is not positioned in the space above the upper end of the coil 23, the housing of the motor 1, and thus the motor 1 itself, can be made smaller.

[0030] Furthermore, the busbar 30 is positioned in the space between the outer circumferential surface of the shaft 10 and the inner circumferential surface of the coil 23, which was previously dead space. As a result, the main body 33 of the conductive member 32 can have a larger radial dimension than before. With this configuration, the axial thickness of the main body 33 can be reduced when the same current density is present, so the axial dimension of the busbar 30 can be reduced compared to before. In the above embodiment, the first terminal 34 extended radially outward from the main body 33, but instead, the first terminal 34 may extend upward in the axial direction by, for example, bending from the main body 33.

[0031] Figure 10 is a schematic perspective view showing the structure of motor 1A according to a second embodiment of the present invention. Figure 11 is a schematic exploded perspective view showing the structure of motor 1A according to a second embodiment of the present invention. In this modified example, in addition to the configuration of motor 1 described above, two first grooves 26 and second grooves 27 extending in the circumferential direction are formed at the upper end of each outer wall 25c of the insulator 22, and one or more outer conductive members 39 are arranged in these two first grooves 26 and second grooves 27. The first groove 26 is located on the inner circumference side of the second groove 27. In this example, as shown in Figure 11, three conductive members 39 are arranged in the circumferential direction. All conductive members 39 have the same shape.

[0032] Each conductive member 39 has an outer peripheral portion 39a extending in the circumferential direction, an inner peripheral portion 39b extending in the circumferential direction, and a connecting portion 39c that connects the outer peripheral portion 39a and the inner peripheral portion 39b to each other. The outer peripheral portion 39a and the inner peripheral portion 39b are offset in the radial and circumferential directions. That is, in the radial direction, the dimensions of the outer peripheral portion 39a are larger than the dimensions of the inner peripheral portion 39b. Also, the outer peripheral portion 39a and the inner peripheral portion 39b do not overlap in the radial direction and are positioned at different locations. The connecting portion 39c extends in the radial direction and connects one end of the outer peripheral portion 39a and one end of the inner peripheral portion 39b in the circumferential direction to each other.

[0033] Each conductive member 39 has one or more third terminals 39d that protrude upward from the outer circumference 39a and the inner circumference 39b, respectively. The third terminals 39d are, for example, fork-shaped terminals. In this example, two third terminals 39d protrude from each outer circumference 39a and the inner circumference 39b. The upper ends of these third terminals 39d are positioned below the upper end of the coil 23. When three conductive members 39 are arranged in the circumferential direction, the outer circumference 39a of one conductive member 39 faces the inner circumference 39b of another conductive member 39 in the radial direction, and the inner circumference 39b of one conductive member 39 faces the outer circumference 39a of another conductive member 39 in the radial direction. At this time, all the third terminals 39d are arranged at predetermined intervals (for example, equal intervals) in the circumferential direction.

[0034] As shown in Figure 10, in the three conductive members 39, the inner circumferential portion 39b is positioned in the first groove 26, and the outer circumferential portion 39a is positioned in the second groove 27. The connecting portion 39c is positioned between the circumferentially adjacent divided insulators 25, 25. With the three conductive members 39 positioned in the first groove 26 and the second groove 27 in this way, a third terminal 39d is positioned corresponding to each divided insulator 25. In this example, two lead wires (not shown) are drawn from each coil 23. One lead wire is electrically connected to the first terminal 34 of the busbar 30, and the other lead wire is electrically connected to the third terminal 39d.

[0035] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0036] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, sizes, etc., are not limited to those exemplified and can be modified as appropriate.

[0037] For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not conflict with the technical requirements. In addition, each component can be selectively combined as appropriate to achieve at least some of the above-mentioned problems and effects. [Explanation of Symbols]

[0038] 1, 1A motor, 10 shaft, 11 rotor, 12 rotor core, 13 first magnet, 14 second magnet, 20 stator, 21 stator core, 22 insulator, 23 coil, 24 segmented core, 24a outer peripheral part, 24b teeth, 24c magnetic pole part, 25 segmented insulator, 25a inner wall, 25b cylinder, 25c outer wall, 25d recess, 26 first groove, 27 second groove, 30 busbar, 31 housing, 32 conductive member, 33 main body, 34 first terminal, 35 second terminal, 36 insulating member, 37 base, 38 cover, 37a housing part, 37b protruding part, 37c recess, 37d convex part, 38a annular part, 38b protruding part, 39 Conductive member, 39a outer circumference, 39b inner circumference, 39c connection part, 39d third terminal, 40 sensor, 41 cylindrical member (cylindrical member), x axis

Claims

1. A busbar having terminals that are electrically connected to an external device, stator and, Equipped with, The terminals of the busbar are located inside the stator of the motor.

2. In the radial direction, the outer circumference of the busbar faces the inner circumference of the stator. The motor according to claim 1.

3. The stator comprises an insulator and a coil wound around the insulator. The motor according to claim 2, wherein the busbar comprises a portion supported by the insulator.

4. In the radial direction, the busbar has a portion that is electrically connected to the coil, In the circumferential direction, the portion supported by the insulator and the portion electrically connected to the coil are arranged side by side. The motor according to claim 3.

5. The insulator comprises an inner wall and a cylinder. The coil is wound around the aforementioned cylinder. The motor according to any one of claims 2 to 4, wherein in the radial direction, the outer circumference of the busbar faces the coil.

6. The shaft and A rotor having a first magnet is fixed to the shaft, The system comprises a second magnet fixed to the aforementioned shaft, The busbar is equipped with a sensor facing the second magnet in the radial direction. The motor according to any one of claims 1 to 5.

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