Motor

Abstract

To provide a motor that can reduce vibration.SOLUTION: A motor 1 comprises a rotor 30 and a stator 20 lying opposite the rotor 30. The stator 20 includes a coil 40. The coil 40 includes a first inclined part 41 and a second inclined part 42, which are inclined to an axial direction. In the axial direction, the first inclined part 41 is longer than the second inclined part 42. According to such a configuration, a harmonic content of dielectric power can be further reduced to reduce the vibration and noise the motor even in a case where inclined parts are provided on a winding wire of the coil 40 in order to obtain a skewing effect.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] It is known to use an air-core coil for a motor, which is formed, for example, by using a self-bonding wire in which a coating layer is covered with a bonding layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 56-115151 [Patent Document 2] Japanese Patent Application Publication No. 60-261337 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-101579 [Patent Document 4] Japanese Patent Application Laid-Open No. 2018-153095 Summary of the Invention [Problem to be solved by the invention]

[0004] Air-core coils may increase vibration due to the generation of harmonic components in the induced electromotive force.

[0005] One aspect of the present invention is to provide a motor capable of reducing vibration. [Means for solving the problem]

[0006] In one embodiment, the motor comprises: a first bearing on one axial side and a second bearing on the other axial side, a frame, and a shaft; Rotor and ,vinegar and a data. The frame has a cylindrical portion that supports the first bearing and a bottom portion that supports the second bearing. The shaft has a first portion that is supported by the cylindrical portion via the first bearing and a second portion that is supported by the bottom portion via the second bearing. The rotor has a rotor yoke and a magnet inside the rotor yoke. The stator is between the magnet and the rotor yoke. The rotor is fixed to the shaft. The stator includes: air core The coil is air core The coils are inclined relative to the axial direction. On one side of the axial direction A first inclined portion; On the other axial sideand a second inclined portion, wherein the first inclined portion is longer than the second inclined portion in the axial direction. The first inclined portion faces the rotor in the radial direction, and the end of the second inclined portion on the first bearing side is positioned closer to the second bearing than the end of the magnet on the second bearing side in the axial direction.

[0007] According to one aspect, vibration can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side cross-sectional view showing an example of a motor according to an embodiment. [Figure 2] FIG. 2 is a perspective view illustrating an example of a coil according to the embodiment. [Figure 3] FIG. 3 is a perspective view illustrating an example of a manufacturing process of the coil according to the embodiment. [Figure 4] FIG. 4 is a perspective view showing an example of a winding before being formed into a ring shape in the embodiment. [Figure 5] FIG. 5 is a plan view showing an example of the positional relationship between the winding and the magnet before being formed into a ring shape in the embodiment. [Figure 6] FIG. 6 is a perspective view showing an example of the positional relationship between the coil and the shaft in the embodiment. [Figure 7] FIG. 7 is an enlarged cross-sectional view showing an example of the positional relationship between the coil and the shaft in the embodiment. [Figure 8] FIG. 8 is a cross-sectional view showing an example of the positional relationship between the coil and the magnet in the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a motor disclosed in the present application will be described in detail with reference to the drawings. Note that the dimensional relationships and ratios of elements in the drawings may differ from reality. The dimensional relationships and ratios may also differ between the drawings. To facilitate understanding of the description, each drawing may illustrate a coordinate system whose axial direction is the direction in which a shaft 91, which will be described later, extends.

[0010] [Embodiment] First, the motor according to the embodiment will be described with reference to Fig. 1. Fig. 1 is a side cross-sectional view showing an example of a motor according to the embodiment. As shown in Fig. 1, the motor 1 according to the embodiment includes a frame 10, a stator 20, a rotor 30, a shaft 91, and bearings 92 and 93. The motor 1 according to the embodiment is, for example, a brushless motor.

[0011] The frame 10 forms a housing for the motor 1. The frame 10 includes a cylindrical portion 11 and a bottom portion 12. The cylindrical portion 11 includes a top surface portion 1A having an end portion 1B. The end portion 1B of the top surface portion 1A supports a bearing 92. The bottom portion 12 includes an end portion 1C and an annular recessed portion 1D. The end portion 1C supports a bearing 93. A second inclined portion 42 and a fourth inclined portion 44 of the coil 40 (described later) are inserted and disposed in the recessed portion 1D. The coil 40 is fixed to the recessed portion 1D of the bottom portion 12, for example, with resin or the like. That is, in this embodiment, the coil 40 is cantilevered by the bottom portion 12 in the axial direction. The rotor 30 and the shaft 91 are rotatably supported relative to the cylindrical portion 11 and the bottom portion 12 of the frame 10. The rotor 30 faces the bottom portion 12 of the frame 10 in the axial direction across a space 19.

[0012] The shaft 91 is supported on the positive axial side by the cylindrical portion 11 via a bearing 92, and on the negative axial side by the bottom portion 12 via a bearing 93. The shaft 91 is fixed to the rotor 30, and rotates together with the rotor 30 to transmit driving force to an external device.

[0013] The rotor 30 has a cup-like shape that covers the coil 40 from the positive axial direction side. The cup-shaped outer peripheral portion of the rotor 30 constitutes the rotor yoke 31. A magnet 80 is disposed on the radially inner side of the rotor 30. The magnet 80 has an end face 81 located on one axial side and an end face 82 located on the other axial side. The rotor yoke 31 rotates around the outer peripheral side of the fixed coil 40, and the magnet 80 rotates around the inner peripheral side of the fixed coil 40. Note that, hereinafter, the positive axial direction side may be referred to as the "one axial direction side," and the negative axial direction side may be referred to as the "other axial direction side."

[0014] The stator 20 faces the rotor 30 in the radial direction. As shown in FIG. 1, the stator 20 is located between the magnet 80 and the rotor yoke 31 in the radial direction. The stator 20 in this embodiment does not have a stator core, and is equipped only with the coil 40. The coil 40 is an air-core coil formed, for example, from a rectangular wire using a self-bonding wire. FIG. 2 is a perspective view showing an example of the coil in this embodiment. As shown in FIG. 2, the windings forming the coil 40 in this embodiment are arranged not parallel to the axial direction but at an angle with respect to the axial direction.

[0015] The coil 40 includes a first inclined portion 41 inclined with respect to one direction D1 and a second inclined portion 42 inclined with respect to a direction D2 different from D1. The coil 40 also includes a third inclined portion 43 inclined with respect to a direction D3 and a fourth inclined portion 44 inclined with respect to a direction D4 different from D3. As shown in FIG. 2, the first inclined portion 41 and the second inclined portion 42 are located on the radially outer side of the coil 40, and the third inclined portion 43 and the fourth inclined portion 44 are located on the radially inner side of the coil 40. Note that terminals 45 and 46, which will be described later, are not shown in FIG. 2.

[0016] The first inclined portion 41 is located on one axial side of the second inclined portion 42, and the third inclined portion 43 is located on one axial side of the fourth inclined portion 44. The first inclined portion 41 is formed continuous with the second inclined portion 42 via a bent portion 49, and the fourth inclined portion 44 is formed continuous with the third inclined portion 43 via a bent portion 49. That is, the angle of the winding forming the coil 40 with respect to the axial direction changes at the bent portion 49. As shown in FIG. 2 , the bent portion 49 is formed by an end portion 4b on the other axial side of the first inclined portion 41 and an end portion 4c on one axial side of the second inclined portion 42, and the bent portion 49 is also formed by an end portion 4f on the other axial side of the third inclined portion 43 and an end portion 4g on one axial side of the fourth inclined portion 44. In this case, the coil 40 does not have a portion that is parallel to the axial direction.

[0017] FIG. 3 is a perspective view showing an example of a manufacturing process for the coil according to the embodiment. As shown in FIG. 3, the coil 40 according to the embodiment is formed, for example, by continuously winding a rectangular wire around a jig T00. In this case, the first inclined portion 41 to the fourth inclined portion 44 constitute one turn of the winding 40A. In this case, the first inclined portion 41 and the third inclined portion 43 are continuously formed via the first folded portion 47. More specifically, the end 4a on one axial side of the first inclined portion 41 and the end 4e on one axial side of the third inclined portion 43 form the first folded portion 47. That is, in the embodiment, the first inclined portion 41 to the fourth inclined portion 44 are continuously formed from a single rectangular wire.

[0018] Furthermore, the fourth inclined portion 44A of the winding 40A and the second inclined portion 42B of the winding 40B, which is different from the winding 40A, are formed continuously via the second folded portion 48. More specifically, the end 4d on the other axial side of the fourth inclined portion 44A and the end 4h on the other axial side of the second inclined portion 42B form the second folded portion 48. As a result, in this embodiment, the windings 40A and 40B are formed continuously from a single rectangular wire. In this case, the first inclined portion 41 and the second inclined portion 42 located radially outward of the coil 40 shown in FIG. 2 and the third inclined portion 43 and the fourth inclined portion 44 located radially inward of the coil 40 are alternately formed around the jig T00. Furthermore, the terminals 45 and 46 of the coil 40 are formed, for example, by pulling out the ends of the winding to one axial side when forming the coil 40.

[0019] By continuously winding the rectangular wire in this manner and then removing the jig T00, a continuous winding is formed as shown in Fig. 4. Fig. 4 is a perspective view showing an example of the winding before being formed into a ring shape in an embodiment. The winding shown in Fig. 4 is then pressed from a direction perpendicular to the axial direction to form a plate shape, and further formed into a ring shape, thereby forming the coil 40 shown in Fig. 2.

[0020] As shown in Fig. 5, coil 40 in the embodiment is formed so that the length of first inclined portion 41 in the axial direction is greater than the length of second inclined portion 42. Fig. 5 is a plan view showing an example of the positional relationship between the winding and the magnet before being formed into a ring shape in the embodiment. As shown in Fig. 5, in the embodiment, when the axial length of coil 40 is L, the axial length h of first inclined portion 41 is set to be within the range shown in the following formula (1).

[0021] 0.7 ≦ h / L ≦ 0.8...Equation (1)

[0022] For example, when the axial length L of the coil 40 shown in Fig. 5 is 54.5 mm, the axial length h of the first inclined portion 41 is set to 40.0 mm. In this case, "h / L" in equation (1) is approximately 0.73.

[0023] FIG. 5 further illustrates the positional relationship between the magnet 80 and the first and second inclined portions 41 and 42. As illustrated in FIG. 5, an end face 81 on one axial side of the magnet 80 is located on the other axial side of the first folded portion 47, which is located on one axial side of the first inclined portion 41. An end face 82 on the other axial side of the magnet 80 is located on the one axial side of the bent portion 49, which is located between the first inclined portion 41 and the second inclined portion 42. That is, the end 4a on one axial side of the first inclined portion 41 and the end 4b on the other axial side protrude axially beyond both end faces 81 and 82 of the magnet 80. In other words, the end faces 81 and 82 of the magnet 80 are located between the end 4a on one axial side of the first inclined portion 41 and the end 4b on the other axial side. Furthermore, in the embodiment, the magnet 80 faces the first inclined portion 41 of the coil 40 in the radial direction, but the second inclined portion 42 and the bent portion 49 do not face the magnet 80 in the radial direction.

[0024] The shapes of the first inclined portion 41 to the fourth inclined portion 44 of the coil 40 will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view showing an example of the positional relationship between the coil and the shaft in the embodiment. FIG. 7 is an enlarged cross-sectional view showing an example of the positional relationship between the coil and the shaft in the embodiment. FIG. 8 is a cross-sectional view showing an example of the positional relationship between the coil and the magnet in the embodiment. FIG. 7 shows a cross-section taken along plane P9 in FIG. 6. FIG. 8 is an enlarged view of the portion shown in frame F1 in FIG. 6.

[0025] In Figures 6 to 8, plane S1 is a plane that includes the center line 99 in the radial direction of the rotor 30 and the end 4a on one axial side of the first inclined portion 41, and plane S2 is a plane that includes the center line 99 and the end 4b on the other axial side of the first inclined portion 41.

[0026] 6 to 8, planes P1, P2, P9, Pu, and Pl are all planes perpendicular to the center line 99. Plane P1 is a plane that includes the end 4a on one axial side of the first inclined portion 41, plane P2 is a plane that includes the end 4d on the other axial side of the second inclined portion 42, and plane P9 is a plane that includes the end 4b on the other axial side of the first inclined portion 41. Plane Pu is a plane that includes the end face 81 on one axial side of the magnet 80, and plane Pl is a plane that includes the end face 82 on the other axial side of the magnet 80. In FIG. 7, the magnet 80, first inclined portion 41, and third inclined portion 43 that are not located on plane P9 are shown by dashed lines.

[0027] 8, a first folded portion 47 formed by one axial end 4a of the first inclined portion 41 and one axial end 4e of the third inclined portion 43 is located on the positive axial side of an end face 81 of a magnet 80 of the rotor 30. Also, a space 19 in the frame 10, i.e., a portion located on the other axial side of an end face 82 on the other axial side of the magnet 80, faces the second inclined portion 42 in the radial direction. Note that in the embodiment, a bent portion 49 formed by the other axial end 4b of the first inclined portion 41 and the other axial end 4c of the second inclined portion 42 may be formed in the space 19.

[0028] In the embodiment, the length M of the magnet 80 in the axial direction is greater than half the length L of the coil 40 in the axial direction, but is smaller than the length h of the first inclined portion 41 in the axial direction.

[0029] As described above, in the embodiment, the first folded portion 47, the second folded portion 48, and the bent portion 49 of the coil 40 are not formed at a position facing the magnet 80 in the radial direction. That is, the bent portion 49 does not face the magnet 80 of the rotor 30 in the radial direction. Furthermore, the axial length h of the first inclined portion 41 facing the magnet 80 in the radial direction is 70% or more of the axial length L of the entire coil 40. This reduces the harmonic components of the induced electromotive force, and can reduce vibration, noise, and the like.

[0030] In addition, in the embodiment, the angle α formed between the end 4a on one axial side of the first inclined portion 41 and the end 4b on the other axial side is calculated by the following equation (2), where p is the number of poles of the magnet 80.

[0031] α=360° / (2×p)...Equation (2)

[0032] For example, when the number of poles p of the magnet 80 is "8," the angle α is "22.5°." In this case, as shown in FIG. 8, the angle α9 formed by the intersection line L9 between the plane S2 and the plane P9 and the intersection line L1 between the plane S1 and the plane P9 is "22.5°." Similarly, when the plane including the end 4f on the other axial side of the third inclined portion 43 and the center line 99 is defined as plane S0, the angle α0 formed by the intersection line between the plane S0 and the plane P9 and the intersection line L1 is also "22.5°."

[0033] As described above, the motor 1 in this embodiment includes the rotor 30 and the stator 20 facing the rotor 30. The stator 20 has a coil 40. The coil 40 has a first inclined portion 41 and a second inclined portion 42, each inclined with respect to the axial direction, and the first inclined portion 41 is longer in the axial direction than the second inclined portion 42. With this configuration, even when an inclined portion is provided in the winding of the coil 40 to obtain a skew effect, the harmonic components of the induced electromotive force can be further reduced, and motor vibration, noise, and the like can be reduced.

[0034] [Variations] Although the configuration of the embodiment has been described above, the embodiment is not limited to this. For example, the coil 40 may be formed from other materials, such as round wire, instead of rectangular wire. Furthermore, the coil 40 may be formed by other methods, such as forming a pattern conductor on an insulating sheet by etching or plating, in addition to the process of winding the coil around the jig T00.

[0035] Furthermore, although the configuration in which the first inclined portion 41 and the second inclined portion 42 and the third inclined portion 43 and the fourth inclined portion 44 are formed symmetrically has been described, this is not limiting and the windings may be formed asymmetrically. Furthermore, the configuration in which the first inclined portion 41, the second inclined portion 42, the third inclined portion 43 and the fourth inclined portion 44 are each formed in a linear shape has been described, this is not limiting and all or some of the inclined portions may be formed in a curved shape as long as they are formed inclined with respect to the axial direction.

[0036] The magnet 80 may be formed integrally with the rotor 30. The rotor yoke 31 may be formed as a separate member from the rotor 30.

[0037] While the present invention has been described above based on the embodiments and modifications, it goes without saying that the present invention is not limited to the embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention. Such modifications without departing from the spirit of the present invention are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims. [Explanation of symbols]

[0038] 1 motor, 10 frame, 11 cylindrical portion, 12 bottom portion, 19 space, 20 stator, 30 rotor, 31 rotor yoke, 40 coil, 41 first inclined portion, 42 second inclined portion, 43 third inclined portion, 44 fourth inclined portion, 45, 46 terminal, 47 first folded portion, 48 second folded portion, 49 bent portion, 80 magnet, 81, 82 end face, 91 shaft, 92, 93 bearing, T00 jig

Claims

1. A first bearing on one axial side and a second bearing on the other axial side; a frame having a cylindrical portion that supports the first bearing and a bottom portion that supports the second bearing; a shaft having a first portion supported by the cylindrical portion via the first bearing and a second portion supported by the bottom portion via the second bearing; a rotor having a rotor yoke and a magnet inside the rotor yoke; a stator between the magnet and the rotor yoke, The rotor is fixed to the shaft, the stator has an air-core coil; the air-core coil has a first inclined portion on one axial side and a second inclined portion on the other axial side, each inclined with respect to the axial direction; The first inclined portion is longer than the second inclined portion in the axial direction, the first inclined portion faces the rotor in the radial direction, In the axial direction, an end portion of the second inclined portion on the first bearing side is disposed closer to the second bearing than an end portion of the magnet on the second bearing side. Motor.

2. A motor as described in claim 1, wherein the first inclined portion and the second inclined portion are formed continuously.

3. A motor as described in claim 2, wherein the end of the first inclined portion protrudes from the magnet in the axial direction.

4. The frame houses the rotor and the stator, the frame includes the cylindrical portion, the bottom portion facing the rotor in the axial direction, and a space between the rotor and the bottom portion, an end portion on one axial side of the second inclined portion is disposed in the space; The motor according to claim 1 or 3.

5. When viewed from one axial side, the angle between a line connecting the end of the first inclined portion on one axial side to the center of the rotor and a line connecting the end of the first inclined portion on the other axial side to the center of the rotor is defined as α, The number of poles of the magnet is p, When α=360° / (2×p) That is, 5. The motor according to claim 1.

6. The axial length of the air-core coil is L, The axial length of the first inclined portion is h, When h / L=0.7~0.8, That is, 6. The motor according to claim 1.

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