Stator assembly, brushless motor and method of manufacturing a stator assembly

Abstract

A brushless motor (10) includes a stator assembly (20) and a rotor (30). The stator assembly (20) includes a stator (40), a housing (21) having a space in which the stator (40) is disposed, and an insulating resin (24) disposed in the space. The housing (21) and the stator (40) are fixed by the insulating resin (24). In addition, the housing (21) includes a first housing member (22) and a second housing member (23). The first housing member (22) and the second housing member (23) are fixed by the insulating resin (24).

Description

Technical Field

[0001] This invention relates to the construction of the stator assembly of a brushless motor. Background Technology

[0002] Patent document 1 describes a brushless motor with an internal rotor type and a single shaft structure.

[0003] Patent Document 1 describes a brushless motor comprising a rotor, a stator, a retainer plate, and a cover assembly. The retainer plate is disposed at one end of the rotor shaft, and the end of the rotor shaft abuts against the retainer plate. The stator is disposed on the outer periphery of the rotor. The stator is fixed to the retainer plate.

[0004] The cover component is a cylindrical shape with one open end, configured to cover the stator and rotor. A retaining plate is fixed to the cover component to cover the opening of the cover component.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-99255

[0006] However, in the construction shown in Patent Document 1, a relatively loud sound is generated due to the vibration caused by the rotation of the rotor. Summary of the Invention

[0007] Therefore, the purpose of this invention is to provide a brushless motor with excellent quietness.

[0008] The stator assembly of the present invention comprises: a stator; a housing having a space for arranging the stator; and an insulating resin disposed in the space. The housing and the stator are fixed together by the insulating resin.

[0009] In this structure, the housing and stator are fixed together with insulating resin, forming an integrated structure. This suppresses excitation vibration and structural resonance.

[0010] According to the present invention, a brushless motor with excellent quietness can be realized. Attached Figure Description

[0011] Figure 1 This is a perspective view of the brushless motor 10 according to the first embodiment of the present invention.

[0012] Figure 2 This is a side sectional view showing the structure of the brushless motor 10 according to the first embodiment of the present invention.

[0013] Figure 3 This is a side sectional view showing the structure of the stator assembly 20 according to the first embodiment of the present invention.

[0014] Figure 4 (A) represents the frequency response of the vibration level. Figure 4 (B) is a graph representing the time characteristic of the temperature rise of the motor.

[0015] Figure 5 This is a flowchart illustrating an example of a method for manufacturing a stator assembly according to an embodiment of the present invention.

[0016] Figure 6 This is a side sectional view showing the structure of the stator assembly 20A according to the second embodiment of the present invention.

[0017] Figure 7 This is an exploded perspective view of the stator assembly 20A according to the second embodiment of the present invention.

[0018] Figure 8 It is a three-dimensional drawing representing other shapes of auxiliary components used for filling. Detailed Implementation

[0019] [First Implementation Method]

[0020] The brushless motor, stator assembly, and manufacturing method thereof according to the first embodiment of the present invention will be described with reference to the accompanying drawings.

[0021] Figure 1 This is a perspective view of the brushless motor 10 according to the first embodiment of the present invention. Figure 2 This is a side sectional view showing the structure of the brushless motor 10 according to an embodiment of the present invention. Figure 3 This is a side sectional view showing the structure of the stator assembly 20 according to an embodiment of the present invention.

[0022] (Brief structure of brushless motor 10)

[0023] like Figure 1 , Figure 2 As shown, the brushless motor 10 includes a stator assembly 20 and a rotor 30. The specific structure of the stator assembly 20 is described below.

[0024] like Figure 2 As shown, the rotor 30 includes a rotor yoke 31, a magnet 32, and a shaft 33. A detailed description of the rotor 30's construction is omitted.

[0025] The stator assembly 20 has an opening 234. The rotor 30 is inserted into the interior of the stator assembly 20 through the opening 234. Viewed from above, the brushless motor 10 (stator assembly 20) appears as follows: Figure 7 As shown, the opening 234 overlaps with the central space 400 of the stator 40. Therefore, the rotor 30 is positioned inside the stator 40. In other words, the stator 40 is positioned on the outer periphery of the rotor 30.

[0026] One end of the shaft 33 of the rotor 30 protrudes outward from the opening 234 of the stator assembly 20. The other end of the shaft 33 of the rotor 30 is supported by the stator assembly 20 to enable rotation.

[0027] In this structure, the rotation of the rotor 30 is controlled by a signal provided to the given element 40. Thus, the brushless motor 10 realizes an internal rotor type and single-shaft brushless motor.

[0028] (The specific structure of stator assembly 20)

[0029] like Figure 1 , Figure 2 , Figure 3 As shown, the stator assembly 20 includes a housing 21, an insulating resin 24, a shaft cover component 25, a bearing 26, an attractive magnet 27, a yoke 28, and a stator 40.

[0030] The housing 21 includes a first housing component 22 and a second housing component 23. The first housing component 22 and the second housing component 23 are made of a material with high rigidity, such as SUS.

[0031] The first housing component 22 includes a main wall 221, a side wall 222, and an inner wall 223. The main wall 221 is circular when viewed from above. The side wall 222 is cylindrical and is formed along the outer periphery of the main wall 221 and extends in a direction orthogonal to the main surface of the main wall 221.

[0032] The inner wall 223 is cylindrical and is formed in the center of the main wall 221, extending in a direction orthogonal to the main surface of the main wall 221. The inner wall 223 has hollow portions 225 with openings on both sides of the cylindrical shape. The main wall 231 has openings in the areas overlapping with the hollow portions 225. Therefore, the hollow portions 225 also communicate with the exterior of the first housing member 22 on the side adjacent to the main wall 231.

[0033] By adopting the above-described structure for the main wall 221, side wall 222, and inner wall 223, the first housing component 22 has a space 224 enclosed by the main wall 221, side wall 222, and inner wall 223. The space 224 is annular in plan view and opens on the side opposite to the side of the main wall 221.

[0034] The second housing component 23 includes a main wall 231 and a side wall 232. The main wall 231 is circular when viewed from above. The side wall 232 is cylindrical when viewed from above. The cylindrical shape of the side wall 232 is formed along the outer periphery of the main wall 231 and extends in a direction orthogonal to the main surface of the main wall 231. Thus, the second housing component 23 has a space 235 enclosed by the main wall 231 and the side wall 232. The space 235 is circular when viewed from above and opens on the side opposite to the side opposite to the main wall 231.

[0035] The main wall 231 has an opening 234 extending through it along its thickness in the center. The opening 234 communicates with the space 235. The opening 234 is circular when viewed from above. The shape of the opening 234 is similar to the shape of the rotor 30 viewed from above (viewed from one end or the other end of the shaft 33). The area of ​​the opening 234 is the area into which the rotor 30 can be inserted, for example, the planar area of ​​the central space 400 of the stator 40.

[0036] Additionally, the main wall 231 has a plurality of holes 236. The plurality of holes 236 penetrate the main wall 231 in the thickness direction and communicate with the space 235. The plurality of holes 236 are arranged along the outer periphery of the opening 234.

[0037] The first housing component 22 and the second housing component 23 are assembled together. More specifically, the first housing component 22 is configured such that the opening of the space 224 faces the second housing component 23, and the second housing component 23 is configured such that the opening of the space 235 faces the first housing component 22. Then, the second housing component 23 is inserted into the first housing component 22 such that the outer wall of the sidewall 232 abuts against the inner wall surface 2221 of the sidewall 222 of the first housing component 22.

[0038] Thus, housing 21 has an internal space. The internal space of housing 21 communicates with the outside of the second housing component 23 through the aforementioned opening 234 and the plurality of holes 236.

[0039] The shaft cover component 25 is circular and has a recessed portion recessed from one main surface. The shaft cover component 25 is disposed near the end of the hollow portion 225 on the side of the main wall 221.

[0040] The bearing 26 is cylindrical and is disposed in the hollow part 225, and is fixed to the wall of the inner wall 223 on the side of the hollow part 225.

[0041] The attracting magnet 27 is ring-shaped. The attracting magnet 27 is disposed at the end of the inner wall 223, in other words, at the end of the inner wall 223 opposite to the connection end connected to the main wall 221.

[0042] The yoke 28 is annular. The shape of the yoke 28 is approximately the same as that of the attracting magnet 27. The yoke 28 is located near the end of the inner wall 223 and is positioned on the side of the main wall 221 of the attracting magnet 27.

[0043] like Figure 7As shown, the stator 40 includes multiple stator cores 41, insulators 42, and multiple coil conductors 43. The stator 40 is annular and has a central space 400. The multiple stator cores 41 are arranged at intervals along the circumference of the annulus. The multiple coil conductors 43 are wound around the multiple stator cores 41, sandwiching the insulators 42 in between. More specifically, the multiple coil conductors 43 are wound around the stator cores 41 with an axis extending outward from the center of the annulus of the stator 40.

[0044] The shape of the stator 40 when viewed from above is approximately the same as the inner wall surface 2221 of the side wall 222 of the first housing component 22, and smaller than the inner wall surface 2221. The shape of the central space of the stator 40 when viewed from above, in other words, the shape of the inner end of the stator 40, is approximately the same as the shape of the rotor 30 described below, and larger than the shape of the rotor 30.

[0045] The stator 40 is disposed within the interior space of the housing 21. More specifically, the stator 40 is configured to be housed within the space 224 of the first housing member 22 and the space 235 of the second housing member 23. In this case, viewed from above, the center of the stator 40 is approximately aligned with the center of the interior space of the housing 21. Furthermore, the outer peripheral end of the stator 40 is close to but does not contact the inner wall surface 2221 of the side wall 222 of the first housing member 22. Moreover, the positioning of the stator 40 relative to the first housing member 22 is achieved, for example, by having the leg members formed on the stator 40 abut against the inner surface of the main wall 221 of the first housing member 22.

[0046] The insulating resin 24 is annular and disposed within the interior space of the housing 21. More specifically, the insulating resin 24 covers approximately the entire stator 40. Furthermore, the insulating resin 24 abuts against approximately the entire inner wall surface 2211 of the main wall 221 of the first housing component 22 and approximately the entire inner wall surface 2221 of the side wall 222. Also, the insulating resin 24 abuts against approximately the entire inner wall surface 2311 of the main wall 231 of the second housing component 23 and approximately the entire inner wall surface 2321 of the side wall 232. Additionally, the cylindrical space formed in the center of the insulating resin 24 is shaped and sized to accommodate the rotor 30.

[0047] With this structure, the stator 40 and the housing 21 are fixed together by insulating resin 24. Furthermore, the first housing component 22 and the second housing component 23 are also fixed together by insulating resin 24. Thus, the structure consisting of the stator 40, the insulating resin 24, the first housing component 22, and the second housing component 23 is integrally formed. As a result, excitation vibration and structural resonance generated in the stator assembly 20 during rotor 30 rotation control are suppressed.

[0048] Figure 4 (A) represents the frequency response of the vibration level. Furthermore, Figure 4 The comparative structure of (A) is one in which the insulating resin 24 is not filled in the housing 21, and the structure that integrates the stator 40 with the housing 21 is not employed. Figure 4 As shown in (A), by using the structure of this embodiment, vibration levels can be suppressed over a wide frequency range.

[0049] Furthermore, the first housing component 22 and the second housing component 23 are not fixed by screws or bolts. Therefore, misalignment between the first housing component 22 and the second housing component 23 caused by screws or bolts is avoided, suppressing unnecessary vibrations caused by such misalignment. Additionally, screws or bolts are not required on the first housing component 22 and the second housing component 23. Therefore, while maintaining the shape of the stator 40, the housing 21 can be miniaturized compared to a structure using screws or bolts.

[0050] Furthermore, the insulating resin 24 is made of a material with a higher thermal conductivity than air. This allows heat generated by the stator 40 to be efficiently transferred to the housing 21 via the insulating resin 24. Therefore, the heat dissipation efficiency of the stator assembly 20 is improved. In particular, in this embodiment, the insulating resin 24 covering the stator 40 is in contact with the first housing component 22 and the second housing component 23. This further improves the thermal conductivity to the first housing component 22 and the second housing component 23, i.e., the housing 21, and further improves the heat dissipation efficiency of the stator assembly 20. Moreover, the insulating resin 24 abuts against approximately the entire surfaces of the inner wall surface 2211, the inner wall surface 2221, the inner wall surface 2311, and the inner wall surface 2321. This further improves the thermal conductivity to the first housing component 22 and the second housing component 23, i.e., the housing 21, and further improves the heat dissipation efficiency of the stator assembly 20.

[0051] Figure 4 (B) represents the time characteristic of the motor's temperature rise. Furthermore, Figure 4 The comparative structure of (B) is a structure in which the insulating resin 24 is not filled in the housing 21. For example... Figure 4 As shown in (B), by using the structure of this embodiment, it is possible to suppress the temperature rise of the motor during transition and reduce the temperature of the motor during stable operation.

[0052] (Manufacturing method of stator assembly 20)

[0053] The stator assembly 20, which is constructed with the above structure, can be manufactured, for example, by the method shown below. Figure 5 This is a flowchart illustrating an example of a method for manufacturing a stator assembly 20 according to an embodiment of the present invention.

[0054] like Figure 5 As shown, firstly, the stator 40 is disposed in the space 224 of the first housing component 22 (S11). Next, the second housing component 23 is installed on the first housing component 22 (S12). More specifically, the second housing component 23 is installed on the first housing component 22 such that the space 224 of the first housing component 22 (corresponding to the "first space" of the present invention) communicates with the space 235 of the second housing component 23 (corresponding to the "second space" of the present invention).

[0055] Next, insulating resin 24 is filled into the internal space of the housing 21 (S13). Specifically, insulating resin 24 flows in and fills the housing 21 through the plurality of holes 236 formed in the second housing member 23. At this time, a mold or the like is inserted into the area where the rotor 30 will be disposed. Thus, insulating resin 24 does not enter the area where the rotor 30 is disposed. Next, insulating resin 24 is cured (S14). Furthermore, the inserted mold can be removed, for example, after the insulating resin 24 has cured.

[0056] By using this manufacturing method, the stator assembly 20 can be easily manufactured.

[0057] [Second Implementation]

[0058] The brushless motor, stator assembly, and manufacturing method thereof according to the second embodiment of the present invention will be described with reference to the accompanying drawings.

[0059] Figure 6 This is a side sectional view showing the structure of the stator assembly 20A according to the second embodiment of the present invention. Figure 7 This is an exploded perspective view of the stator assembly 20A according to the second embodiment of the present invention. Furthermore, in Figure 7 The description of insulating resin 24 is omitted. In other words, Figure 7 This is a diagram showing the state of insulating resin 24 before it is filled and cured.

[0060] like Figure 6 , Figure 7 As shown, the stator assembly 20A of the brushless motor in the second embodiment differs from the stator assembly 20 of the first embodiment in that it includes the filling auxiliary member 50. The other structures of the stator assembly 20A are the same as those of the stator assembly 20, and the description of the same parts is omitted.

[0061] The stator assembly 20A includes a filling auxiliary component 50. The filling auxiliary component 50 is cylindrical and made of a non-magnetic insulating resin. The filling auxiliary component 50 corresponds to the "auxiliary component" of this invention.

[0062] The filling auxiliary component 50 includes a cylindrical main body 51 and an annular bottom 52. The main body 51 and the bottom 52 are integrally formed, for example. The bottom 52 is disposed at one axial end of the cylindrical part of the main body 51.

[0063] The filling auxiliary member 50 is configured such that the circumferential surface of the main body 51 approaches and extends along the inner circumferential end of the stator 40. The bottom 52 abuts against the main wall 221 of the first housing member 22, and the end of the main body 51 opposite to the bottom 52 abuts against the main wall 231 of the second housing member 23. Thus, the stator 40 is disposed within the space enclosed by the filling auxiliary member 50, the main wall 221 and side wall 222 of the first housing member 22, and the main wall 231 of the second housing member 23.

[0064] Insulating resin 24 is filled in the space enclosed by the filling auxiliary component 50, the main wall 221 and side wall 222 of the first housing component 22, and the main wall 231 of the second housing component 23.

[0065] In addition, such as Figure 7 As shown, the filling auxiliary member 50 has an annular fixing part at its bottom, which is fixed to the main wall 221 of the first housing member 22 by an adhesive material or the like. This suppresses movement of the filling auxiliary member 50 when filling the insulating resin 24. Therefore, the insulating resin 24 can be filled into the desired space.

[0066] By using this structure, the insulating resin 24 can be reliably filled into the desired space without using the molds shown in the first embodiment. Furthermore, the rotor 30 can be inserted into the stator assembly 20 without waiting for the insulating resin 24 to cure, thus shortening the manufacturing time.

[0067] Figure 8 This is a perspective view showing other shapes of the auxiliary component 50 used for filling. (and) Figure 7 The filling auxiliary component 50 shown differs from the main body 51 in that it has a plurality of protrusions 53 arranged at intervals along the circumferential surface of the main body 51.

[0068] By providing multiple protrusions 53, the stator 40 can be arranged between the stator core 41 of the stator 40 and the multiple protrusions 53. As a result, for example, the amount of insulating resin 24 can be reduced.

[0069] In the structures of the various embodiments described above, it indicates that the insulating resin 24 is filled entirely into the space surrounding the stator 40. However, as long as the bottom of the stator 40 is embedded in the insulating resin 24 to a predetermined depth, the above-mentioned effects can be achieved. This state refers to the state of "fixing the housing to the stator" in this invention. In other words, the state of "fixing the housing to the stator" in this invention refers to the state of joining and bonding the housing and stator as a single unit, relative to the state where vibration causes the housing and stator to be treated as an integral part. The definition of "fixing" is the same for the joining and bonding of the first housing component 22 and the second housing component 23.

[0070] Furthermore, for example, if the insulating resin 24 fills more than 70% of the space surrounding the stator 40, the aforementioned effects can be obtained more effectively.

[0071] Explanation of reference numerals in the attached figures

[0072] 10... Brushless motor; 20, 20A... Stator assembly; 21... Housing; 22... First housing component; 23... Second housing component; 24... Insulating resin; 25... Shaft cover component; 26... Bearing; 27... Attracting magnet; 28... Yoke; 30... Rotor; 31... Rotor yoke; 32... Magnet; 33... Shaft; 40... Stator; 41... Multiple stator cores; 42... Insulator; 43... Coil conductor; 50... Filling auxiliary component.

Claims

1. A stator assembly capable of internally arranging a rotor, comprising: stator; A housing having space for the stator to be configured; and An insulating resin disposed in the space. The housing includes: A first housing component has a first main wall that is circular when viewed from above and a cylindrical first side wall formed along the outer peripheral end of the first main wall and extending in a direction orthogonal to the main surface of the first main wall. The first housing component has a first opening by covering one end of the first side wall in the extending direction with the first main wall, while leaving the other end of the first side wall uncovered in the extending direction. The second housing component has a second main wall that is circular when viewed from above, and a second opening formed in a shape that penetrates the second main wall, having an opening area smaller than the first opening. The second housing component is disposed on the first housing component and on the other end of the first sidewall in the direction of extension, such that the center of the second opening is aligned with the center of the first opening. The second opening is an opening for allowing the rotor shaft to protrude outwards from the stator assembly. The space enclosed by the first housing component and the second housing component forms an opposing space between the first main wall and the second main wall, constituting a space for the stator to be configured. In the space enclosed by the first housing component and the second housing component, in a top view, at the portion where the central part of the first opening and the second opening overlap, the space for arranging the rotor is configured such that the rotor as a whole is arranged more centrally than the space for arranging the stator. The first housing component, the second housing component, and the stator are secured by the insulating resin filling the space in which the stator is configured.

2. The stator assembly according to claim 1, wherein, The insulating resin surface is in contact with the inner wall surface of the first housing component and the inner wall surface of the second housing component.

3. The stator assembly according to claim 1 or 2, wherein, The insulating resin has a higher thermal conductivity than air.

4. The stator assembly according to claim 1 or 2, wherein, The stator assembly includes an auxiliary component disposed along the inner circumferential end of the stator, which, together with the housing, surrounds the stator and the insulating resin.

5. The stator assembly according to claim 4, wherein, The auxiliary component has multiple protrusions that are sandwiched between multiple stator cores constituting the stator.

6. A brushless electric motor, comprising: The stator assembly according to any one of claims 1 to 5; and The rotor, which is disposed inside the stator, The rotor shaft protrudes from the second opening toward the outside of the stator assembly.

7. A method for manufacturing a stator assembly, comprising the steps of manufacturing a stator assembly capable of internally arranging a rotor: A stator is disposed in a first housing component. The first housing component has a first main wall that is circular when viewed from above and a cylindrical first side wall formed along the outer peripheral end of the first main wall and extending in a direction orthogonal to the main surface of the first main wall. The first housing component has a first opening by covering one end of the first side wall in the extending direction with the first main wall and leaving the other end of the first side wall in the extending direction uncovered. A second housing component is disposed at the other end of the first sidewall of the first housing component in the extending direction. The second housing component has a second main wall that is circular when viewed from above, and a second opening formed in a shape that penetrates the second main wall and has an opening area smaller than the first opening. The center of the second opening is aligned with the center of the first opening. The second opening is an opening for the rotor shaft to protrude outward from the stator assembly. The space enclosed by the first housing component and the second housing component forms an opposing space between the first main wall and the second main wall, constituting a space for stator configuration. In the space enclosed by the first housing component and the second housing component, in a position closer to the center than the space for stator configuration when viewed from above, the central portion of the first opening and the second opening overlap, such that the rotor as a whole is arranged closer to the center than the stator, thus constituting a space for rotor configuration. The insulating resin flows into the portion of the space enclosed by the first housing component and the second housing component, which is covered by the second housing component and where the stator is disposed, and the insulating resin abuts against the stator, the inner wall surface of the first housing component forming the internal space, and the inner wall surface of the second housing component forming the second space. as well as The insulating resin is then cured.

8. The method for manufacturing a stator assembly according to claim 7, wherein, The manufacturing method of this stator assembly also includes the following steps: Prior to the process of configuring the stator, auxiliary components for forming the space are installed on the first housing component.

9. The method for manufacturing a stator assembly according to claim 8, wherein, The auxiliary component has a cylindrical main body, an annular bottom, and multiple protrusions on the circumferential surface of the main body, and these are integrally formed.

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