JP2017118747A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor capable of preventing the invasion of a small insect from a drain passage provided on a bushing to the inside of a motor contour, in the electric motor which includes a bushing type having a pair of holding pieces for holding a lead wire in a sandwiched manner.SOLUTION: A bushing 6 includes a pair of a first holding piece 61 and a second holding piece 62 to hold a lead wire 51 in a sandwiched manner. The first holding piece 61 out of the pair of the first and second holding pieces 61, 62 includes a contact surface 681 which contacts along the outer peripheral surface 421 of a second bracket 42 which covers the outer peripheral surface 402 of a motor contour 40. The contact surface 681 includes second drain passages 72, disposed on both sides in the width direction, to drain water generated inside the motor contour 40. The second drain passages 72 are formed in juxtaposition in such a manner that a plurality of triangularly hollowed small grooves 721 are adjacently disposed from the contact surface 681.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electric motor including a bushing for pulling out a lead wire connected to a circuit board from the inside of a motor shell to the outside.

  As a conventional electric motor, there is an inner rotor type electric motor in which a rotor having a permanent magnet is rotatably arranged inside a stator that generates a rotating magnetic field. As this type of electric motor, for example, there is a brushless DC motor for rotationally driving a blower fan mounted on an outdoor unit of an air conditioner.

  Such an electric motor includes, for example, a stator, a rotor, and a circuit board that are covered with a motor outer made of resin, and a bushing for drawing a lead wire connected to the circuit board from the inside of the motor outer to the outside. I have. The motor outer shell has an end surface perpendicular to the axial direction of the rotor and an outer peripheral surface formed continuously from the end surface and parallel to the axial direction of the rotor on the circuit board side where the bushing is disposed.

  As this bushing, for example, there is a type having a pair of holding pieces for holding a lead wire from both sides (for example, Patent Document 1). Of the pair of holding pieces, one holding piece is formed in a substantially L shape, and is contacted along the outer peripheral surface of the motor outer shell, and a first contact portion that contacts the end surface of the motor outer shell. The second contact portion is provided.

  In the electric motor having such a bushing, when water such as condensed water is generated inside the motor shell, it is necessary to drain the generated water to the outside of the motor shell. For this reason, as a countermeasure for draining water inside the motor shell, for example, a drainage passage that communicates the inside and outside of the motor shell is directed from the first contact portion provided on one holding piece of the bushing toward the second contact portion. Can be considered.

  However, for example, in an electric motor mounted on an outdoor unit of an air conditioner, depending on the size of the drainage passage formed in one holding piece of the bushing, a small insect such as an ant enters the inside of the motor shell from the drainage passage. However, there is a possibility of causing a short circuit of wiring and parts provided on the circuit board.

JP 2013-138551 A

  In view of the above-mentioned problems, the present invention relates to an electric motor having a type of bushing having a pair of holding pieces that hold a lead wire from both sides. It is an object of the present invention to provide an electric motor that can prevent this from occurring.

  In order to solve the above problems, an electric motor of the present invention includes a stator, a rotor, and a circuit board covered with a motor outline, and a bushing for pulling out a lead wire connected to the circuit board from the inside of the motor outline to the outside. The outer shell of the motor has an end surface formed perpendicular to the axial direction of the rotor on the side of the circuit board on which the bushing is disposed, and an outer peripheral surface formed parallel to the axial direction of the rotor so as to be continuous with the end surface; The bushing has a pair of holding pieces that hold the lead wire in between, and one holding piece of the pair of holding pieces has a contact surface that contacts the outer peripheral surface of the motor outer shell, and the contact surface has a width. A drainage passage for draining water generated inside the motor shell is provided on both sides or one side of the direction, and the drainage passage is a plurality of minute grooves recessed from the contact surface.

  According to the electric motor of the present invention, in an electric motor having a type of bushing having a pair of holding pieces that are held with a lead wire sandwiched between them, a small insect is allowed to enter the inside of the motor shell from a drainage passage provided in the bushing. Can be prevented.

It is a side view including the partial cross section which shows the electric motor provided with the bushing of this invention. It is explanatory drawing which shows the position of the motor outline in which the bushing of the electric motor of this invention is arrange | positioned, (a) is a partial front view, (b) is a partial external appearance perspective view which shows a bushing and a motor outline. It is an external appearance perspective view which shows the bushing of the electric motor of this invention. It is explanatory drawing which shows the state which has arrange | positioned the bushing of the electric motor of this invention in the motor outline, (a) is a partial side view, (b) is the partial front view of the A arrow direction of (a), (c) is ( It is a partial bottom view of the B arrow direction of a). It is a fragmentary top view which shows the state which contacted the bushing of the electric motor of this invention to the motor outer shell. It is explanatory drawing which shows the magnitude | size of the groove | channel formed in the bushing of the electric motor of this invention.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 thru | or FIG. 6 is a figure explaining the electric motor in this embodiment. As shown in FIGS. 1 to 6, the electric motor 1 is an inner rotor type electric motor in which a rotor 3 is rotatably arranged inside a stator 2. For example, a blower fan mounted on an outdoor unit of an air conditioner Is a brushless DC motor for rotationally driving the motor.

  As shown in FIG. 1, the electric motor 1 includes a cylindrical stator 2 and a rotor 3 disposed coaxially with the stator 2 on the inner diameter side of the stator 2, and the stator 2 is synthesized in a mold. The resin is integrally formed with the stator core 21 so that the entire surface is covered with a motor shell 40 made of synthetic resin, leaving the tooth surface 22 of the stator core 21.

  A motor outer shell 40 that covers one end surface side (left side in FIG. 1) of the stator 2 is provided with a first bracket 41 that accommodates a bearing 33 that supports a shaft 32 (described later) provided in the rotor 3. A circuit board 5 on which a control unit for driving the electric motor 1 is mounted is mounted on the motor shell 40 that covers the other end face side (right side in FIG. 1) of the stator 2, and the shaft 32 is supported so as to cover the circuit board 5. A second bracket 42 in which another bearing 34 is housed is provided. A motor outer shell 40 that covers the outer peripheral side of the stator 2 (the outer peripheral surfaces of the left and right central portions in FIG. 1) is provided with a second bracket 42 and a third bracket 43 for strengthening the fixing of the motor outer shell 6. .

  The rotor 3 includes a shaft 32 that is rotatably supported by bearings 33 and 34, and a cylindrical rotor body 31 that is coaxially attached to the shaft 32 and has a plurality of rotor magnets on the outer diameter side. . At both ends of the stator 2 and the rotor 3, the first bracket 41 is integrally formed with the motor outer shell 40, the second bracket 42 is press-fitted into the motor outer shell 40, and the third bracket 43 is crimped onto the second bracket 42, A waterproof structure is formed by closing the inside of 40.

  A bushing 6 is provided between the motor outer shell 40 and the second bracket 42 for drawing out the lead wire 51 connected to the circuit board 5 from the inside of the motor outer shell 40 to the outside. In describing the bushing 6, first, the structure of the motor outer shell 40 against which the bushing 6 is abutted will be described.

  As shown in FIGS. 1, 2, and 5, the motor shell 40 is formed on the non-output side (the bearing 34 side) of the shaft 32 and is continuous to the end surface 401 and the end surface 401 perpendicular to the axial direction of the shaft 32. An outer peripheral surface 402 that is formed and parallel to the axial direction of the shaft 32 is formed. On the outer peripheral edge of the end surface 401 (right side in FIG. 1) of the motor outer shell 40, an outer peripheral convex portion 406 that is continuously formed on the end surface 401 and protrudes in the axial direction of the shaft 32 is provided. As shown in FIGS. 2 and 5, the outer peripheral convex portion 406 is provided with a notch 403 at a place where the circuit board 5 is placed and the bushing 6 is disposed. The notch 403 is notched so as to have an opening width corresponding to the width of the bushing 6 from the outer periphery of the motor outer shell 40 toward the inside. Here, the width of the bushing 6 includes a width of a first contact portion 67 described later, side walls 673 and 673 formed on both sides of the first contact portion 67, and side walls 405 formed on both sides of the notch portion 403. 405 and the gap 711 between them.

  On the outer peripheral side of the notch 403, a second bracket 42 that covers the outer peripheral surface 402 of the motor outer shell 40 is provided between the outer peripheral surface 402 of the motor outer shell 40 and a second contact portion 68 described later of the bushing 6. A second contact portion 68 described later of the bushing 6 is in contact with the outer peripheral surface 421 of the second bracket 42. Note that the second contact portion 68 may be in direct contact with the outer peripheral surface 402 of the motor outer shell 40. Further, on the outer peripheral side of the notch 403, a locking convex portion 404 that is continuously formed on the end surface 401 and protrudes in the axial direction of the shaft 32 is formed at the center in the circumferential direction of the end surface 401. The locking projection 404 supports the bushing 6 by locking a locking recess 672 formed in a first contact portion 67 described later of the bushing 6.

  As shown in FIGS. 3, 4, and 5, the bushing 6 includes a pair of first holding pieces 61 and second holding pieces 62 that are held with the lead wire 51 interposed therebetween. Each of the two holding pieces 62 is made of an insulating synthetic resin. Each of the first holding piece 61 and the second holding piece 62 has a first facing surface 63 and a second facing surface 64 that face each other and contact each other. A first guide portion 65 and a second guide portion that are recessed from the first facing surface 63 and the second facing surface 64 to guide the lead wire 51 on the first facing surface 63 and the second facing surface 64, respectively. 66.

  The first holding piece 61 is formed in an L shape, and includes a first contact portion 67 that contacts the end surface 401 of the motor outer shell 40 and an outer peripheral surface 421 of the second bracket 42 that covers the outer peripheral surface 402 of the motor outer shell 40. A second abutting portion 68 having an abutting surface 681 that abuts along. The first abutting portion 67 and the second abutting portion 68 are formed on both sides of the first holding piece 61 in the width direction from the first abutting portion 67 to the second abutting portion 68. A drainage passage 7 for draining water such as generated dew condensation water is provided.

  As shown in FIGS. 2, 3, and 5, the drainage passage 7 is provided on both sides of the side walls 673 and 673 formed on both sides of the first contact portion 67 and the notch portion 403 provided on the outer peripheral convex portion 407. Contact surfaces 681 on both sides in the width direction of the first drainage passage 71 in which a gap 711 is formed between the formed side walls 405 and 405 and the contact surface 681 that contacts the outer peripheral surface 421 of the second bracket 42. A plurality of (for example, 10 in this embodiment) minute grooves 721 that are recessed in a triangular shape are provided with a second drainage passage 72 formed side by side so as to be adjacent to each other. Here, when the electric motor 1 is mounted on an outdoor unit of an air conditioner, the installation state of the electric motor 1 is such that the shaft 32 extends in the horizontal direction and the bushing 6 extends vertically from the motor shell 40 as shown in FIGS. It is assumed that it extends downward in the direction. In the drainage passage 7 provided in the first holding piece 61 of the bushing 6 at this time, the first drainage passage 71 is a passage extending in the vertical direction and the second drainage passage 72 is extending in the horizontal direction. The water generated in the step is dropped through the first drainage passage 71 and the water dropped through the second drainage passage 72 is branched and drained.

  As shown in FIG. 6, the opening width D1 and the depth D2 of the plurality of grooves 721 of the second drainage passage 72 are formed in a minute size so that small insects such as ants do not enter. The opening width D1 and the depth D2 of the plurality of grooves 721 of the second drainage passage 72 are, for example, a worm (total length 2 mm, head (vertical width 0.15 mm, horizontal width 0.5 mm)) , The opening width D1 is set to 0.45 mm, and the depth D2 is set to 0.3 mm. As shown in FIGS. 4 and 5, the opening width D1 and the depth D2 of the plurality of grooves 721 of the second drainage passage 72 are such that the second abutting portion 68 of the bushing 6 contacts the outer peripheral surface 421 of the second bracket 42. When in contact, it corresponds to a gap in the cross section between the second drainage passage 72 and the outer peripheral surface 421 of the second bracket 42, and the head of the cedar (length 0.15 mm, width 0.5 mm) in this gap Does not enter the triangular groove 721.

  According to the electric motor 1 according to the present embodiment described above, the bushing 6 has a pair of first holding pieces 61 and second holding pieces 62 that hold the lead wire 51 therebetween, and the pair of first holding pieces 61 and The first holding piece 61 (one holding piece) of the second holding pieces 62 includes an abutting surface 681 that abuts along the outer peripheral surface 421 of the second bracket 42, and the abutting surfaces 681 are on both sides in the width direction. A second drainage passage 72 (drainage passage) for draining water generated inside the motor shell 40 is provided, and the second drainage passage 72 (drainage passage) is a plurality of minute concaves that are recessed in a triangular shape from the contact surface 681. The grooves 721 are formed side by side so as to be adjacent to each other. As a result, in the electric motor 1 including the type of bushing 6 having a pair of first holding pieces 61 and second holding pieces 62 that are held with the lead wire 51 interposed therebetween, insects are discharged from the drainage passage 7 provided in the bushing 6. Intrusion to the inside of the motor shell 40 can be prevented.

  In the electric motor 1 according to the present embodiment, the contact surface 681 is provided with the second drainage passage 72 (drainage passage) for draining water generated inside the motor shell 40 on both sides in the width direction. The present invention is not limited to this, and the contact surface 681 may include a second drainage passage 72 (drainage passage) on one side in the width direction.

  In the electric motor 1 according to the present embodiment, the structure is such that a plurality of minute grooves 721 that are recessed in a triangular shape are formed from the contact surface 681 that contacts the outer peripheral surface 421 of the second bracket 42. Not limited to this, a structure in which a plurality of minute grooves 721 recessed in a rectangular shape or a circular shape may be formed. In this case, the opening width D1 and the depth D2 of the plurality of grooves 721 of the second drainage passage 72 are, for example, Himeari (total length 2 mm, head (vertical width 0.15 mm, horizontal width 0.5 mm)), as described above. Is set to a size that prevents the head of the Himeari from entering.

  In the electric motor 1 according to the present embodiment, a plurality of minute grooves 721 that are recessed from the contact surface 681 that contacts the outer peripheral surface 421 of the second bracket 42 are formed so as to be adjacent to each other. The invention is not limited to this, and a structure in which a plurality of minute grooves 721 are formed side by side at intervals may be employed.

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Stator 21 Stator core 3 Rotor 31 Rotor main body 32 Shaft 33, 34 Bearing 40 Motor outer surface 401 End surface 402 Outer peripheral surface 403 Notch part 404 Locking convex part 405 Both side walls 406 Outer peripheral convex part 41 1st bracket 42 2nd bracket 421 Outer circumference Surface 43 Third bracket 5 Circuit board 51 Lead wire 6 Bushing 61 First holding piece 62 Second holding piece 63 First facing surface 64 Second facing surface 65 First guide portion 66 Second guide portion 67 First contact Portion 671 Contact surface 672 Locking recess 673 Side wall 68 Second contact portion 681 Contact surface 7 Drainage passage 71 First drainage passage 711 Gap 72 Second drainage passage 721 Groove D1 Opening width of multiple grooves 721 D2 Multiple grooves 721 depth

Claims (2)

A stator, a rotor and a circuit board covered with a motor shell, and a bushing for drawing a lead wire connected to the circuit board from the inside of the motor shell to the outside,
The outer surface of the motor has an end surface formed perpendicular to the axial direction of the rotor on the circuit board side where the bushing is disposed, and an outer peripheral surface formed parallel to the axial direction of the rotor so as to be continuous with the end surface. With
The bushing has a pair of holding pieces to hold the lead wire in between,
One holding piece of the pair of holding pieces includes a contact surface that contacts the outer peripheral surface of the motor outer shell,
The contact surface includes drainage passages for draining water generated inside the motor shell on both sides or one side in the width direction,
The electric motor characterized in that the drainage passage is a plurality of minute grooves recessed from the contact surface.   2. The bracket according to claim 1, further comprising a bracket that covers the outer peripheral surface of the motor outer shell between the outer peripheral surface of the motor outer shell and the contact surface, and the contact surface contacts the outer peripheral surface of the bracket. The electric motor described.

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