Brushless motor

Abstract

To provide a brushless motor whose assembly man hour can be reduced.SOLUTION: A brushless motor comprises: a rotor 14; a stator 16 accommodated inside a rotor housing; a center piece 18 which holds the stator; a circuit board 20 arranged on the opposite side of the stator to a body part 42 of the center piece; a motor holder 22 provided around the rotor housing; and a circuit case 24 arranged on the opposite side of the stator to the body part and fixed to the motor holder. A first elastomer member 70 is provided at an outer peripheral part of the body part, the center piece is elastically supported to the motor holder by holding an outer peripheral part 70A of the first elastomer member by the motor holder and the circuit case, a part between the outer peripheral part of the body part and the outer peripheral part of the circuit case is sealed by holding an inner peripheral part 70B of the first elastomer member by the body part and the circuit case.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a brushless motor. [Background technology]

[0002] Conventionally, the following brushless motors have been known: For example, the brushless motor described in Patent Document 1 includes a rotor having a cylindrical rotor housing with a top, a stator housed inside the rotor housing, a center piece having a main body facing the opening of the rotor housing and holding the stator, a circuit board located on the opposite side of the stator relative to the main body of the center piece, a motor holder provided around the rotor housing, and a circuit case located on the opposite side of the stator relative to the main body of the center piece and housing the circuit board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-184547 Summary of the Invention [Problem to be solved by the invention]

[0004] In a brushless motor having the above configuration, if a vibration-damping member that damps vibration by elastically supporting the center piece against the motor holder and a dustproof / waterproof member that seals the gap between the outer periphery of the main body and the outer periphery of the circuit case are provided separately, the assembly work will increase.

[0005] The technology of the present disclosure aims to provide a brushless motor that can reduce the number of assembly steps compared to conventional brushless motors. [Means for solving the problem]

[0006] A brushless motor (10) according to one aspect of the disclosed technique includes a rotor (14) having a cylindrical rotor housing (28), a stator (16) accommodated inside the rotor housing, a main body (42) facing an opening (28A) of the rotor housing, a center piece (18) for holding the stator, a circuit board (20) arranged on the opposite side of the main body from the stator, a motor holder (22) provided around the rotor housing, and a motor holder (23) arranged on the opposite side of the main body from the stator. and a circuit case (24) arranged on the side of the motor holder, accommodating the circuit board and fixed to the motor holder, a vibration-isolating member (70) is provided on the outer periphery (42A) of the main body portion, and the center piece is elastically supported relative to the motor holder by the vibration-isolating member being sandwiched between the motor holder and the circuit case, and the gap between the outer periphery of the main body portion and the outer periphery (24A) of the circuit case is sealed by the vibration-isolating member being sandwiched between the main body portion and the circuit case.

[0007] According to the technique of the present disclosure, a brushless motor is provided that can reduce the number of assembly steps compared to conventional brushless motors. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a brushless motor according to a first embodiment of the technique of the present disclosure. [Figure 2] 2 is a longitudinal cross-sectional view of the brushless motor according to the first embodiment of the disclosed technique taken along line F2-F2 in FIG. 1. FIG. [Figure 3] 1 is a perspective view of a center piece according to a first embodiment of the disclosed technique, viewed from one axial side. [Figure 4] 10 is a perspective view of the center piece according to the first embodiment of the disclosed technology, viewed from the other axial side. FIG. [Figure 5] 1 is a longitudinal cross-sectional view of a main portion of a brushless motor according to a first embodiment of the disclosed technique. [Figure 6] FIG. 6 is an enlarged view of part A in FIG. 5. [Figure 7]FIG. 6 is an enlarged view of part B in FIG. 5. [Figure 8] 3 is a longitudinal cross-sectional view of a main part of the brushless motor according to the first embodiment of the disclosed technique, taken at a position different from that in FIG. 2. FIG. [Figure 9] FIG. 9 is an enlarged view of part C in FIG. 8. [Figure 10] FIG. 10 is a perspective view of a center piece according to a second embodiment of the disclosed technique, viewed from one axial side. [Figure 11] FIG. 11 is a perspective view of a motor holder according to a second embodiment of the technique of the present disclosure, as viewed from the other axial side. [Figure 12] FIG. 10 is a longitudinal sectional view of a brushless motor according to a second embodiment of the disclosed technique. [Figure 13] FIG. 10 is a longitudinal sectional view showing a modified example of a brushless motor according to the second embodiment of the technique of the present disclosure. [Figure 14] FIG. 10 is a plan view showing a brushless motor according to a third embodiment of the disclosed technique, with the motor holder not shown. [Figure 15] FIG. 10 is a longitudinal sectional view of a brushless motor according to a third embodiment of the disclosed technique. [Figure 16] FIG. 10 is a vertical cross-sectional view showing a first modified example of a brushless motor according to a third embodiment of the technique of the present disclosure. [Figure 17] FIG. 10 is a vertical cross-sectional view showing a second modified example of a brushless motor according to the third embodiment of the technique of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] [First embodiment] First, a first embodiment of the technique of the present disclosure will be described.

[0010] A brushless motor 10 of the first embodiment shown in Fig. 1 is a fan motor used in a blower mounted on a vehicle such as a passenger automobile. As shown in Fig. 2, brushless motor 10 includes a motor shaft 12, a rotor 14, a stator 16, a center piece 18, a circuit board 20, a motor holder 22, a circuit case 24, and a heat sink 26. In each figure, arrow Z1 indicates one axial side of brushless motor 10, and arrow Z2 indicates the other axial side of brushless motor 10.

[0011] The rotor 14 has a cylindrical rotor housing 28 with an opening 28A and a rotor magnet 30 fixed to the inside of the peripheral wall of the rotor housing 28. A cylindrical fixing portion 32 is formed in the center of the ceiling of the rotor housing 28, and the motor shaft 12 is press-fitted into the fixing portion 32. The tip of the motor shaft 12 protrudes from the rotor housing 28 to one axial side of the brushless motor 10.

[0012] The stator 16 is housed inside the rotor housing 28. The stator 16 is disposed radially inside the rotor magnet 30 and facing the rotor magnet 30. The stator 16 has a stator core 34 and a plurality of windings 36. The plurality of windings 36 are wound around a plurality of teeth 38 formed radially on the stator core 34, with a resin insulator 40 interposed between them. The entire stator 16, including the stator core 34 and the plurality of windings 36, forms an annular shape.

[0013] Center piece 18 is made of resin. Center piece 18 has a main body 42 facing opening 28A of rotor housing 28, a cylindrical support portion 44 protruding from the center of main body 42 toward stator 16, and a cylindrical support member 46 attached to support portion 44 from one axial side of brushless motor 10. Main body 42 is formed in a roughly disk shape with its thickness direction aligned with the axial direction of brushless motor 10. Main body 42 is sized to face the entire opening 28A of rotor housing 28.

[0014] The support portion 44 and the support member 46 are inserted inside the annular stator core 34. The stator core 34 is fixed to the main body portion 42, for example, by screws, thereby holding the stator 16 to the centerpiece 18. A bearing accommodating portion 48 is formed in the main body portion 42, and a bearing accommodating portion 50 is formed in the support member 46. A bearing 52 is housed in each of the bearing accommodating portions 48, 50, and the motor shaft 12 is press-fitted into the bearing 52. The motor shaft 12 is supported by the support portion 44 and the support member 46 via the bearing 52, so that the rotor 14 is rotatably supported with respect to the centerpiece 18.

[0015] The circuit board 20 is disposed on the opposite side of the main body 42 from the stator 16. The circuit board 20 is fixed to the main body 42, for example, by screws or the like. A plurality of switching elements (not shown) are mounted on the circuit board 20 for switching the current supplied to the plurality of windings 36. The current supplied to the plurality of windings 36 is switched by the plurality of switching elements, thereby forming a rotating magnetic field in the stator 16. Furthermore, the formation of the rotating magnetic field in the stator 16 generates attractive and repulsive forces between the stator 16 and the rotor 14, causing the rotor 14 to rotate.

[0016] The motor holder 22 is made of, for example, resin, and is provided around the rotor housing 28. The motor holder 22 has a cylindrical portion 54 that surrounds the rotor housing 28, and an annular portion 56 that extends radially outward from the cylindrical portion 54. The annular portion 56 is formed in the shape of an annular plate with its thickness direction aligned with the axial direction of the brushless motor 10. A plurality of mounting portions 58 are provided on the outer periphery of the annular portion 56. The brushless motor 10 is fixed to the object by attaching the plurality of mounting portions 58 to the object.

[0017] The circuit case 24 is formed in a flat container shape and is attached to the main body 42 with its opening facing the main body 42. The circuit case 24 is disposed on the opposite side of the main body 42 from the stator 16, and houses the circuit board 20. The circuit case 24 is fixed to the motor holder 22 by, for example, screws.

[0018] An extension portion 60 is formed in the motor holder 22, extending radially outward from the brushless motor 10. The extension portion 60 is formed in a duct shape. An air intake 62 is formed at the tip of the extension portion 60. The air intake 62 opens toward one axial side of the brushless motor 10. An air intake flow path 64 is formed inside the extension portion 60. The air intake flow path 64 extends from the air intake 62 toward the main body 42.

[0019] The heat sink 26 is made of a metal such as aluminum that has high thermal conductivity. The heat sink 26 is fixed to the circuit board 20 by screws or the like. The heat sink 26 is connected to a plurality of switching elements mounted on the circuit board 20 in a manner that allows heat to be transferred therethrough. The heat sink 26 has a heat dissipation section 66 that is disposed on the main body section 42 side of the circuit board 20. The heat dissipation section 66 protrudes to one axial side of the brushless motor 10 relative to the circuit board 20. Air (i.e., cooling air W) sent from the air intake passage 64 is supplied to the heat dissipation section 66, thereby cooling the heat dissipation section 66.

[0020] As shown in FIGS. 3 and 4 , the main body 42 of the center piece 18 is provided with a first elastomer member 70, a second elastomer member 72, and a third elastomer member 74. The first elastomer member 70 is an example of a “vibration-damping member” according to the technology of the present disclosure. The second elastomer member 72 is an example of a “first seal member” according to the technology of the present disclosure. The third elastomer member 72 is an example of a “second seal member” according to the technology of the present disclosure. The first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are formed of elastomer. As an example, the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are provided on the main body 42 by two-color molding. Note that, instead of the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74, pre-molded members having shapes similar to those of the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 may be used.

[0021] The first elastomer member 70 is provided on the outer circumferential portion 42A of the main body portion 42. The outer circumferential portion 42A of the main body portion 42 refers to the portion of the main body portion 42 on the outer circumferential side. The first elastomer member 70 is formed in an annular shape along the periphery of the main body portion 42. As shown in FIGS. 5 to 7 , a hook portion 76 having a bent hook shape that protrudes in the axial direction of the brushless motor 10 is formed on the outer circumferential portion 42A of the main body portion 42. The hook portion 76 protrudes toward the circuit case 24 (i.e., the other axial side of the brushless motor 10). The hook portion 76 is formed in an annular shape along the periphery of the main body portion 42. The first elastomer member 70 is divided by the hook portion 76 into an outer circumferential portion 70A and an inner circumferential portion 70B. That is, the portion of the first elastomer member 70 that is radially outward from the hook portion 76 is the outer circumferential portion 70A, and the portion of the first elastomer member 70 that is radially inward from the hook portion 76 is the inner circumferential portion 70B.

[0022] The hook portion 76 forms the outermost portion (i.e., the outer edge portion) of the outer peripheral portion 42A of the main body portion 42. The outer peripheral portion 70A is provided radially outward of the brushless motor 10 than the hook portion 76 (i.e., the outer edge portion). The inner peripheral portion 70B is provided radially inward of the brushless motor 10 than the hook portion 76 (i.e., the outer edge portion) and on the circuit case 24 side of the outer peripheral portion 42A of the main body portion 42 (i.e., the other axial side of the brushless motor 10). The hook portion 76 is embedded between the outer peripheral portion 70A and the inner peripheral portion 70B of the first elastomer member 70 from one axial side of the brushless motor 10.

[0023] The outer periphery 22A of the motor holder 22 and the outer periphery 24A of the circuit case 24 face each other in the axial direction of the brushless motor 10. The outer periphery 22A of the motor holder 22 refers to the outer periphery of the motor holder 22. The outer periphery 24A of the circuit case 24 refers to the outer periphery of the circuit case 24. The outer periphery 22A of the motor holder 22 is located on one axial side of the brushless motor 10 relative to the outer periphery 24A of the circuit case 24.

[0024] The center piece 18 is elastically supported relative to the motor holder 22 by sandwiching the outer circumferential portion 70A of the first elastomer member 70 between the outer circumferential portion 22A of the motor holder 22 and the outer circumferential portion 24A of the circuit case 24. Elastically supporting the center piece 18 relative to the motor holder 22 ensures vibration isolation for the brushless motor 10. This prevents vibrations from the rotor 14 and stator 16, which are sources of vibration, from being transmitted to the motor holder 22.

[0025] The outer circumferential portion 42A of the main body 42 and the outer circumferential portion 24A of the circuit case 24 face each other in the axial direction of the brushless motor 10. The outer circumferential portion 42A of the main body 42 is located radially inward of the brushless motor 10 relative to the outer circumferential portion 22A of the motor holder 22. The outer circumferential portion 42A of the main body 42 is located on one axial side of the brushless motor 10 relative to the outer circumferential portion 24A of the circuit case 24.

[0026] The gap between the outer periphery 42A of the main body 42 and the outer periphery 24A of the circuit case 24 is sealed by sandwiching the inner periphery 70B of the first elastomer member 70 between the outer periphery 42A of the main body 42 and the outer periphery 24A of the circuit case 24. Sealing the gap between the outer periphery 42A of the main body 42 and the outer periphery 24A of the circuit case 24 ensures dustproof and waterproof properties for the circuit board 20. This prevents dust and water droplets from entering through the gap between the outer periphery 42A of the main body 42 and the outer periphery 24A of the circuit case 24 toward the circuit board 20.

[0027] The second elastomer member 72 is provided on the surface of the main body 42 facing the circuit board 20 (see FIG. 4). The second elastomer member 72 is formed in an annular shape around the bearing accommodating portion 48 formed in the main body 42. The second elastomer member 72 has an annular portion 78 and a plurality of protrusions 80 protruding radially outward from the annular portion 78 (see FIG. 4). As shown in FIGS. 5 and 6, the brushless motor 10 includes a connecting member 82. The connecting member 82 extends along the axial direction of the brushless motor 10 and penetrates the main body 42 and the heat sink 26. The connecting member 82 connects the windings 36 wound around the stator 16 to the circuit board 20.

[0028] The gap between the connecting member 82 and the main body 42 is sealed by a protrusion 80 of the second elastomer member 72. Specifically, the connecting member 82 passes through the protrusion 80 provided in the through-hole 84 of the main body 42, thereby sealing the gap between the connecting member 82 and the main body 42 by the protrusion 80 of the second elastomer member 72. By sealing the gap between the connecting member 82 and the main body 42, dust and water resistance is ensured for the circuit board 20. This prevents dust and water droplets from entering through the gap between the connecting member 82 that passes through the main body 42 and the main body 42 toward the circuit board 20.

[0029] 8 and 9, brushless motor 10 includes a connector member 86. Connector member 86 has a connector case 88 and a connector terminal 90. A mounting hole 92 that penetrates through main body 42 in the axial direction of brushless motor 10 is formed, and connector case 88 has a convex mounting portion 94. Connector case 88 is assembled to main body 42 with mounting portion 94 inserted into mounting hole 92. One end of connector terminal 90 penetrates heat sink 26 and is connected to circuit board 20.

[0030] The third elastomer member 74 is provided on the inner periphery of a mounting hole 92 formed in the main body 42. The third elastomer member 74 seals the gap between the inner periphery of the mounting hole 92 and the outer periphery of the mounting portion 94. By sealing the gap between the inner periphery of the mounting hole 92 and the outer periphery of the mounting portion 94, dust and water resistance is ensured for the circuit board 20. This prevents dust and water droplets from entering through the gap between the inner periphery of the mounting hole 92 and the outer periphery of the mounting portion 94 toward the circuit board 20.

[0031] Next, the operation and effects of the first embodiment will be described.

[0032] As described above in detail, in the brushless motor 10 according to the first embodiment, the first elastomer member 70 is provided on the outer circumferential portion 42A of the main body portion 42. The center piece 18 is elastically supported relative to the motor holder 22 by sandwiching the outer circumferential portion 70A of the first elastomer member 70 between the motor holder 22 and the circuit case 24. The gap between the outer circumferential portion 42A of the main body portion 42 and the outer circumferential portion 24A of the circuit case 24 is sealed by sandwiching the inner circumferential portion 70B of the first elastomer member 70 between the main body portion 42 and the circuit case 24. Therefore, the number of assembly steps can be reduced compared to, for example, separately providing a vibration-proofing member that provides vibration isolation by elastically supporting the center piece 18 relative to the motor holder 22 and a dustproof / waterproofing member that provides dustproof / waterproofing by sealing the gap between the outer circumferential portion 42A of the main body portion 42 and the outer circumferential portion 24A of the circuit case 24.

[0033] Furthermore, a hook portion 76 having a bent hook shape is formed on the outer circumferential portion 42A of the main body portion 42 so as to protrude in the axial direction of the brushless motor 10. The first elastomer member 70 is divided into an outer circumferential portion 70A and an inner circumferential portion 70B by the hook portion 76, and the hook portion 76 is fitted between the outer circumferential portion 70A and the inner circumferential portion 70B of the first elastomer member 70. Therefore, the hook portion 76 increases the contact area between the outer circumferential portion 42A of the main body portion 42 and the first elastomer member 70, thereby reducing the pressure acting between the outer circumferential portion 42A of the main body portion 42 and the first elastomer member 70 and ultimately enabling the brushless motor 10 to withstand large forces acting between the center piece 18 and the motor holder 22. This improves the vibration-proofing properties of the brushless motor 10.

[0034] Furthermore, the hook portion 76 protrudes toward the circuit case 24. Therefore, for example, compared to when the hook portion 76 protrudes toward the opposite side from the circuit case 24, the portion from the outer circumferential portion 42A of the main body portion 42 to the outer circumferential portion 70A of the first elastomer member 70 can be made flat. This makes it possible to prevent the cross-sectional area of ​​the air intake channel 64 formed by the extension portion 60 from becoming smaller, and ultimately reduces the loss of the cooling air W taken into the air intake channel 64.

[0035] Brushless motor 10 also includes a first elastomer member 70 provided on outer circumferential portion 42A of main body 42, a second elastomer member 72 provided between connecting member 82 and main body 42, and a third elastomer member 74 provided between main body 42 and connector member 86. Therefore, first elastomer member 70 ensures vibration resistance of brushless motor 10 and dustproofness and waterproofness of circuit board 20, and second elastomer member 72 and third elastomer member 74 also ensure dustproofness and waterproofness of circuit board 20.

[0036] Furthermore, the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are provided on the main body portion 42 by two-color molding. Therefore, the number of assembly steps can be reduced compared to when the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are separate from the main body portion 42.

[0037] Furthermore, the hook portion 76 protrudes toward the circuit case 24, the outer peripheral portion 70A of the first elastomer member 70 is provided radially outward of the brushless motor 10 relative to the hook portion 76, and the inner peripheral portion 70B of the first elastomer member 70 is provided on the circuit case 24 side relative to the outer peripheral portion 42A of the main body portion 42. Therefore, the first elastomer member 70 can be formed relative to the outer peripheral portion 42A of the main body portion 42 by two-color molding from the other axial side of the brushless motor 10.

[0038] Furthermore, in addition to the first elastomer member 70, the second elastomer member 72 and the third elastomer member 74 can also be formed by two-shot molding on the main body portion 42 from the other axial side of the brushless motor 10. This allows the upper mold, which is the mold on one axial side of the main body portion 42, to be shared when the main body portion 42 and the support portion 44 of the center piece 18 are resin-molded using a mold that is divided in the axial direction of the brushless motor 10. Furthermore, when the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are two-shot molded, only the lower mold needs to be replaced, thereby reducing costs compared to replacing both the upper and lower molds.

[0039] Next, a modification of the first embodiment will be described.

[0040] In the above embodiment, a more preferred form is that the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 are integrally formed on the main body portion 42 by two-color molding, but at least one of the first elastomer member 70, the second elastomer member 72, and the third elastomer member 74 may be formed separately from the main body portion 42.

[0041] Furthermore, in the above embodiment, a more preferred form is one in which the hook portion 76 protrudes toward the circuit case 24 side (i.e., the other axial side of the brushless motor 10) and the inner peripheral portion of the elastomer member is provided on the circuit case 24 side relative to the outer peripheral portion 42A of the main body portion 42; however, the hook portion 76 may protrude toward the opposite side from the circuit case 24 (i.e., one axial side of the brushless motor 10) and the inner peripheral portion 70B of the first elastomer member 70 may be divided into a portion provided on the circuit case 24 side relative to the outer peripheral portion 42A of the main body portion 42 and a portion provided on the opposite side from the circuit case 24 relative to the outer peripheral portion 42A of the main body portion 42.

[0042] [Second embodiment] Next, a second embodiment of the technique of the present disclosure will be described.

[0043] In the second embodiment, the configuration of the brushless motor 10 is modified as follows compared to the first embodiment. That is, as shown in FIG. 10, the inner peripheral portion 70B of the first elastomer member 70 has a plurality of pressed portions 100 arranged in the circumferential direction of the center piece 18. Each pressed portion 100 is formed in a columnar shape that protrudes to one axial side of the center piece 18. The plurality of pressed portions 100 are provided at equal intervals. The number of the pressed portions 100 is, for example, three or more.

[0044] On the other hand, as shown in FIG. 11, the outer peripheral portion 22A of the motor holder 22 has a plurality of pressing portions 102 arranged in the circumferential direction of the motor holder 22. Each pressing portion 102 is formed as a protrusion that protrudes toward the other axial side of the motor holder 22. The tip portion of each pressing portion 102 is formed in a pointed shape. As shown in FIG. 12, when the brushless motor 10 is assembled, the plurality of pressing portions 102 press against the plurality of pressed portions 100, respectively, and the tip portion of each pressing portion 102 is recessed into the top surface of the pressed portion 100. The plurality of pressing portions 102 are provided at equal intervals. The number of the plurality of pressing portions 102 is, for example, three or more.

[0045] However, when the brushless motor 10 is installed as a blower motor in a vehicle body or the like, the natural frequency of the blower motor may resonate with other components or systems to which it is installed, resulting in noise. In the second embodiment, the natural frequency of the blower motor can be changed, for example, by changing the locations or number of the multiple pressing portions 102. The locations or number of the multiple pressing portions 102 can be selected as desired depending on the natural frequency of the blower motor. For example, when the motor holder 22 is formed by resin molding using a mold, the locations or number of the multiple pressing portions 102 can be changed by changing the insert used to form the multiple pressing portions 102.

[0046] The inner circumferential portion 70B of the first elastomer member 70 has a seal portion 104 that extends annularly along the circumferential direction of the center piece 18. The seal portion 104 is formed in a rib shape that protrudes toward the other axial side of the center piece 18. The seal portion 104 is pressed against the outer circumferential portion 24A of the circuit case 24. The multiple pressed portions 100 are respectively pressed by the multiple pressing portions 102, and the seal portion 104 is pressed against the outer circumferential portion 24A of the circuit case 24, whereby the inner circumferential portion 70B of the first elastomer member 70 is sandwiched between the motor holder 22 and the circuit case 24. The center piece 18 is elastically supported relative to the motor holder 22 by sandwiching the inner circumferential portion 70B of the first elastomer member 70 between the motor holder 22 and the circuit case 24.

[0047] Furthermore, by pressing the seal portion 104 against the outer circumferential portion 24A of the circuit case 24, the inner circumferential portion 70B of the first elastomer member 70 is sandwiched between the main body portion 42 of the center piece 18 and the circuit case 24. The space between the outer circumferential portion 42A of the main body portion 42 and the outer circumferential portion 24A of the circuit case 24 is sealed by the inner circumferential portion 70B of the first elastomer member 70 being sandwiched between the main body portion 42 and the circuit case 24.

[0048] The outer peripheral portion 70A of the elastomer member 70 is inserted between the outer peripheral portion 22A of the motor holder 22 and the outer peripheral portion 24A of the circuit case 24. The outer peripheral portion 70A of the elastomer member 70 may be in zero-touch contact with the outer peripheral portion 22A of the motor holder 22 and the outer peripheral portion 24A of the circuit case 24 without being pressed against them, or may have a gap between them.

[0049] Furthermore, the main body 42 of the centerpiece 18 has a plurality of openings 106 (see FIG. 10) that penetrate the centerpiece 18 in the axial direction. The plurality of openings 106 are closed by, for example, a resin portion (not shown) that is integrally formed with the support member 46 (see FIG. 2).

[0050] As described above in detail, in the second embodiment as well, the first elastomer member 70 is provided on the outer circumferential portion 42A of the main body portion 42. The center piece 18 is elastically supported relative to the motor holder 22 by sandwiching the first elastomer member 70 between the motor holder 22 and the circuit case 24. The gap between the outer circumferential portion 42A of the main body portion 42 and the outer circumferential portion 24A of the circuit case 24 is sealed by sandwiching the first elastomer member 70 between the main body portion 42 and the circuit case 24. Therefore, the number of assembly steps can be reduced compared to, for example, when a vibration-proofing member that provides vibration isolation by elastically supporting the center piece 18 relative to the motor holder 22 and a dustproof / waterproofing member that provides dustproof / waterproofing by sealing the gap between the outer circumferential portion 42A of the main body portion 42 and the outer circumferential portion 24A of the circuit case 24 are separately provided.

[0051] Furthermore, in the second embodiment, the natural frequency of the blower motor can be changed by changing the locations or number of the multiple pressing portions 102. One method for changing the natural frequency of the blower motor is to change the material (e.g., hardness) of the first elastomer member 70 to change the spring constant of the first elastomer member 70. However, this method requires removing all of the material of the first elastomer member 70 from the mold that molds the first elastomer member 70 and cleaning the mold, which is time-consuming. In contrast, in the second embodiment, when changing the locations or number of the multiple pressing portions 102, it is only necessary to change the nesting member used to form the multiple pressing portions 102, and therefore the natural frequency of the blower motor can be easily changed.

[0052] Furthermore, each of the multiple pressing portions 102 is formed as a protrusion that protrudes toward the other axial side of the motor holder 22. Therefore, in order to form the multiple pressing portions 102, it is sufficient to use local nests that correspond to the respective pressing portions 102, which simplifies the configuration of the nests.

[0053] 13 , the motor holder 22 may have a rib 108 extending in the circumferential direction of the motor holder 22, and the multiple pressing portions 102 may be formed on the rib 108. In other words, portions of the rib 108 extending in the circumferential direction of the motor holder 22 that correspond to each pressed portion 100 may be formed as each pressing portion 102.

[0054] With this configuration, the surface pressure of each pressing portion 102 is uniform in the circumferential direction of the motor holder 22, so that the motor shaft 12 can be prevented from tilting.

[0055] [Third embodiment] Next, a third embodiment of the technique of the present disclosure will be described.

[0056] In the third embodiment, the configuration of the brushless motor 10 is modified as follows compared to the first embodiment. That is, as shown in FIG. 14, the outer peripheral portion 42A of the main body 42 has multiple protrusions 110 arranged in the circumferential direction of the center piece 18. Each of the multiple protrusions 110 protrudes radially outward from the center piece 18. As shown in FIG. 15, each protrusion 110 overlaps with the outer peripheral portion 22A of the motor holder 22 in the radial direction of the center piece 18. As an example, each protrusion 110 contacts the outer peripheral portion 22A of the motor holder 22. The multiple protrusions 110 are provided at equal intervals. The number of the multiple protrusions 110 is, for example, three or more.

[0057] As described above, in the third embodiment, the multiple protrusions 110 overlap with the outer periphery 22A of the motor holder 22 in the radial direction of the center piece 18. As a result, each protrusion 110 supports the center piece 18 relative to the outer periphery 22A of the motor holder 22, and therefore, tilting of the motor shaft 12 (see FIG. 14) can be suppressed more effectively than when the multiple protrusions 110 do not overlap with the outer periphery 22A of the motor holder 22 (see FIG. 9, for example).

[0058] Furthermore, each protrusion 110 is in contact with the outer periphery 22A of the motor holder 22. This makes it possible to prevent the motor shaft 12 from tipping over, compared to when each protrusion 110 is spaced apart from the outer periphery 22A of the motor holder 22, for example.

[0059] As shown in FIG. 16, the first elastomer member 70 may have an intervening portion 112 interposed between each protrusion 110 and the outer circumferential portion 22A of the motor holder 22. As shown in FIG. 17, the protrusions 110 may be formed on the outer circumferential portion 42A of the main body 42 via a stepped portion 114. The stepped portion 114 may then be provided with an intervening portion 112. Even with this configuration, tilting of the motor shaft 12 can be suppressed more effectively than when the multiple protrusions 110 do not overlap the outer circumferential portion 22A of the motor holder 22. The intervening portions 112 also improve vibration damping.

[0060] The above describes the first to third embodiments of the technology of the present disclosure, but among the configurations described in the first to third embodiments, configurations that can be combined may be implemented in appropriate combinations.

[0061] Furthermore, the technology of the present disclosure is not limited to the above, and it goes without saying that it can be implemented in various modifications other than those described above without departing from the spirit of the invention.

[0062] Below, supplementary notes are provided regarding the technology of the present disclosure. (Appendix 1) a rotor (14) having a cylindrical rotor housing (28); a stator (16) housed inside the rotor housing; a center piece (18) having a main body (42) facing the opening (28A) of the rotor housing and holding the stator; a circuit board (20) disposed on the opposite side of the main body from the stator; a motor holder (22) provided around the rotor housing; a circuit case (24) disposed on the opposite side of the main body from the stator, accommodating the circuit board, and fixed to the motor holder; Equipped with a vibration-isolating member (70) is provided on the outer periphery (42A) of the main body; the center piece is elastically supported with respect to the motor holder by the vibration-proof member being sandwiched between the motor holder and the circuit case, The gap between the outer periphery of the main body and the outer periphery of the circuit case (24A) is sealed by sandwiching the vibration-isolating member between the main body and the circuit case. Brushless motor (10). (Appendix 2) A hook portion (76) having a bent hook shape is formed on the outer periphery of the main body portion so as to protrude in the axial direction of the brushless motor, The vibration-damping member is divided into an outer circumferential portion and an inner circumferential portion by the hook portion, The hook portion is embedded between the outer circumferential portion and the inner circumferential portion of the vibration-damping member. 2. A brushless motor as defined in claim 1. (Appendix 3) The hook portion protrudes toward the circuit case, an outer circumferential portion of the vibration-proof member is provided radially outward of the brushless motor relative to the hook portion, an inner peripheral portion of the vibration-proof member is provided on the circuit case side relative to an outer peripheral portion of the main body; 2. A brushless motor as defined in claim 2. (Appendix 4) The vibration-damping member is provided on the outer periphery of the main body by two-color molding. A brushless motor according to any one of Supplementary Note 1 to Supplementary Note 3. (Appendix 5) The vibration-damping member has a plurality of pressed portions (100) arranged in the circumferential direction of the center piece, The outer periphery of the motor holder has a plurality of pressing portions (102) that press the plurality of pressed portions, respectively. A brushless motor according to any one of Supplementary Note 1 to Supplementary Note 4. (Appendix 6) The plurality of pressing portions are each formed as a protrusion that protrudes in the axial direction of the motor holder. 6. The brushless motor according to claim 5. (Appendix 7) The motor holder has a rib (108) extending in the circumferential direction of the motor holder, The plurality of pressing portions are formed on the rib. 6. The brushless motor according to claim 5. (Appendix 8) The outer periphery of the main body has a plurality of protrusions (110) arranged in the circumferential direction of the center piece, Each of the plurality of protrusions protrudes radially outward from the center piece and overlaps an outer periphery of the motor holder in the radial direction of the center piece. A brushless motor according to any one of Supplementary Note 1 to Supplementary Note 7. (Appendix 9) Each of the protrusions is in contact with an outer periphery of the motor holder. 9. The brushless motor according to claim 8. (Appendix 10) The vibration-proof member has an interposition portion (112) interposed between each of the protrusions and the outer periphery of the motor holder. 9. The brushless motor according to claim 8. (Appendix 11) a connector member (86) assembled to the main body; a connecting member (82) that penetrates the main body and connects the windings wound around the stator to the circuit board; a first seal member (72) provided between the connecting member and the main body; a second seal member (74) provided between the main body portion and the connector member; Equipped with A brushless motor according to any one of claims 1 to 10. (Appendix 12) a rotor having a cylindrical rotor housing with a top end; a stator housed inside the rotor housing; a center piece having a main body portion facing the opening of the rotor housing and holding the stator; a circuit board disposed on the opposite side of the main body from the stator; a motor holder provided around the rotor housing; a circuit case disposed on the opposite side of the main body from the stator, accommodating the circuit board, and fixed to the motor holder; a connector member assembled to the main body; a connecting member that penetrates the main body and connects the windings wound around the stator to the circuit board; a vibration-isolating member provided on the outer periphery of the main body; a first seal member provided between the connecting member and the main body portion; a second seal member provided between the main body and the connector member; Equipped with Brushless motor. [Explanation of symbols]

[0063] 10...brushless motor, 12...motor shaft, 14...rotor, 16...stator, 18...center piece, 20...circuit board, 22...motor holder, 22A...periphery, 24...circuit case, 24A...periphery, 26...heat sink, 28...rotor housing, 28A...opening, 30...rotor magnet, 32...fixing portion, 34...stator core, 36...winding, 38...teeth, 40...insulator, 42...main body, 42A...periphery, 44...support portion, 46...support member, 48...bearing accommodating portion, 50...bearing accommodating portion, 52...bearing, 54...cylindrical portion, 56...ring portion, 58...mounting portion, 60...extending portion, 62...air intake port, 64...air intake channel, 66...heat dissipation portion, 70...first elastomer member, 70A...outer peripheral portion, 70B...inner peripheral portion, 72...second elastomer member, 74...third elastomer member, 76...hook portion, 78...annular portion, 80...protruding portion, 82...connecting member, 84...through hole, 86...connector member, 88...connector case, 90...connector terminal, 92...mounting hole, 94...mounting portion, 100...pressed portion, 102...pressing portion, 104...sealing portion, 106...opening, 108...rib, 110...protruding portion, 112...intervening portion, 114...step portion

Claims

1. a rotor (14) having a cylindrical rotor housing (28); a stator (16) housed inside the rotor housing; a center piece (18) having a main body (42) facing the opening (28A) of the rotor housing and holding the stator; a circuit board (20) disposed on the opposite side of the main body from the stator; a motor holder (22) provided around the rotor housing; a circuit case (24) disposed on the opposite side of the main body from the stator, accommodating the circuit board, and fixed to the motor holder; Equipped with A vibration-isolating member (70) is provided on the outer periphery (42A) of the main body portion, the center piece is elastically supported with respect to the motor holder by the vibration-proof member being sandwiched between the motor holder and the circuit case, The gap between the outer periphery of the main body and the outer periphery of the circuit case (24A) is sealed by sandwiching the vibration-isolating member between the main body and the circuit case. A brushless motor (10).

2. A hook portion (76) having a bent hook shape is formed on the outer periphery of the main body portion so as to protrude in the axial direction of the brushless motor, The vibration-damping member is divided into an outer circumferential portion and an inner circumferential portion by the hook portion, The hook portion is embedded between the outer circumferential portion and the inner circumferential portion of the vibration-damping member.

2. The brushless motor according to claim 1.

3. The hook portion protrudes toward the circuit case, an outer circumferential portion of the vibration-proof member is provided radially outward of the brushless motor relative to the hook portion, an inner peripheral portion of the vibration-proof member is provided on the circuit case side relative to an outer peripheral portion of the main body; 3. The brushless motor according to claim 2.

4. The vibration-damping member is provided on the outer periphery of the main body by two-color molding.

2. The brushless motor according to claim 1.

5. The vibration-damping member has a plurality of pressed portions (100) arranged in the circumferential direction of the center piece, The outer periphery of the motor holder has a plurality of pressing portions (102) that press the plurality of pressed portions, respectively.

2. The brushless motor according to claim 1.

6. The plurality of pressing portions are each formed as a protrusion that protrudes in the axial direction of the motor holder.

6. The brushless motor according to claim 5.

7. The motor holder has a rib (108) extending in a circumferential direction of the motor holder, The plurality of pressing portions are formed on the rib.

6. The brushless motor according to claim 5.

8. The outer periphery of the main body has a plurality of protrusions (110) arranged in the circumferential direction of the center piece, Each of the plurality of protrusions protrudes radially outward from the center piece and overlaps an outer periphery of the motor holder in the radial direction of the center piece.

2. The brushless motor according to claim 1.

9. Each of the protrusions is in contact with an outer periphery of the motor holder.

9. The brushless motor according to claim 8.

10. The vibration-damping member has an interposition portion (112) interposed between each of the protrusions and the outer periphery of the motor holder.

9. The brushless motor according to claim 8.

11. a connector member (86) assembled to the main body; a connecting member (82) that penetrates the main body and connects the windings wound around the stator to the circuit board; a first seal member (72) provided between the connecting member and the main body portion; a second seal member (74) provided between the main body portion and the connector member; Equipped with The brushless motor according to any one of claims 1 to 10.

12. a rotor having a cylindrical rotor housing with a top end; a stator housed inside the rotor housing; a center piece having a main body portion facing the opening of the rotor housing and holding the stator; a circuit board disposed on the opposite side of the main body from the stator; a motor holder provided around the rotor housing; a circuit case disposed on the opposite side of the main body from the stator, accommodating the circuit board, and fixed to the motor holder; a connector member assembled to the main body; a connecting member that penetrates the main body and connects the windings wound around the stator to the circuit board; a vibration-isolating member provided on the outer periphery of the main body; a first seal member provided between the connecting member and the main body portion; a second seal member provided between the main body portion and the connector member; Equipped with Brushless motor.

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