JP5591184B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

  Some DC brushless motors as electric motors have a structure in which a rotor is arranged in an upper case in which a stator around which a coil is wound is fitted. Further, the printed circuit board is fixed to the stator in the upper case, and further the lower case is attached. In the DC brushless motor having such a structure, in order to improve the heat dissipation, a technique in which a stator and a rotor are arranged in a stator case, and electronic parts are arranged and molded on the bottom surface of the case having a bearing housing structure. For example, it is disclosed in Patent Document 1.

  Further, for example, Patent Document 2 discloses a technique for partitioning the inside of a case into a circuit space in which a substrate is provided and a motor space in which a stator and a rotor are provided by partitioning the upper case and the lower case using a bracket. Has been. In Patent Document 2, a pin extending from a stator is passed through a hole formed in a substrate, and the pin and the substrate are soldered at the hole portion. A through hole is also formed in the bracket for penetrating the pin extending from the stator. By providing a moisture-proof material in the through-hole portion formed in the bracket, moisture is prevented from entering the circuit space from the motor space.

JP 2001-128417 A JP 2011-66980 A

  However, according to the above conventional technique, when the moisture-proof material is applied to the through-hole portion of the bracket and then the substrate is arranged, the moisture-proof material may ooze out from the hole formed in the substrate in order to pass the pins. . The moisture-proof material that oozes out from the hole through which the pin passes obstructs the solder joint between the pin and the substrate, and the quality of the solder joint cannot be ensured. On the other hand, if the substrate is placed after the moisture-proof material is dried in order to prevent the moisture-proof material from seeping out, there is a problem that the processing time increases and the cost increases.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an electric motor that can suppress the seepage of the moisture-proof material from the hole in the substrate and can improve the quality and the cost.

  In order to solve the above-described problems and achieve the object, the present invention includes a stator, a frame that accommodates the stator therein, a rotor disposed inside the stator, a shaft coupled to the rotor, and a shaft. A bracket that is rotatably supported, a board that is disposed on the opposite side of the stator with respect to the bracket, and a pin that is erected on the stator and electrically connects the stator and the board. A through hole penetrating is formed, and a depression is formed around the through hole.

  According to the present invention, the positional deviation between the stator and the bracket and the positional deviation between the substrate and the bracket are suppressed, the deterioration of the positioning accuracy between the Hall IC and the stator is suppressed, the deterioration of the efficiency and the abnormal noise are suppressed. There is an effect that it is possible to suppress the occurrence of.

FIG. 1 is a side view of the DC brushless motor according to the first embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view in which the portion A of FIG. 1 is enlarged. FIG. 3 is a plan view of the bracket portion, and is an arrow view seen along the arrow B shown in FIG. FIG. 4 is a plan view of the substrate. FIG. 5 is a plan view of the stator. FIG. 6 is a plan view of the bracket portion after the substrate is mounted, and is a view taken along the arrow B shown in FIG. 7 is a cross-sectional view taken along line CC shown in FIG. FIG. 8 is a circuit block diagram of the electric motor. FIG. 9 is a partial enlarged cross-sectional view of a portion corresponding to a portion A shown in FIG. 1 in a conventional electric motor as a comparative example.

  Hereinafter, an electric motor and a ventilation fan according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a side view of the DC brushless motor according to the first embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view in which the portion A of FIG. 1 is enlarged. FIG. 3 is a plan view of the bracket portion, and is an arrow view seen along the arrow B shown in FIG. FIG. 4 is a plan view of the substrate. FIG. 5 is a plan view of the stator. FIG. 6 is a plan view of the bracket portion after the substrate is mounted, and is a view taken along the arrow B shown in FIG. 7 is a cross-sectional view taken along line CC shown in FIG. FIG. 8 is a circuit block diagram of the electric motor. In FIG. 1, in order to explain the internal structure of the DC brushless motor 31, a part is shown in cross section.

  In the DC brushless motor 31 as an electric motor, each element is housed inside an outer shell constituted by the frame 1 and the cover 6. A stator 2 is press-fitted into the inner diameter of the metallic frame 1 having the housing 1a. The stator 2 is configured by winding a coil 2b around an iron core 2a.

  A spring 14 for applying an appropriate load to the bearing 4 is inserted into the housing 1a. The rotor shaft 3 is disposed inside the stator 2. The rotor shaft 3 includes a shaft 3a and a bearing 4 and a rotor 3b. The bearing 4 supports the shaft 3a in a rotatable manner. The rotor 3b has an annular shape.

  The bracket 5 includes a stator side protrusion 5a and a bracket flange 5c. The stator-side protrusion 5a is inserted into the inner diameter of the frame 1, and the bracket flange 5c is sandwiched between the frame flange 1b formed on the frame 1 and the cover flange 6a formed on the cover 6, so that the frame 1 and the cover 6 The bracket 5 is positioned and fixed with respect to the outer shell.

  The bracket 5 is integrally formed with a bracket housing (shaft holding portion) 5e. The bracket housing 5e is erected on the outer periphery of the shaft 3a, and is formed so as to surround the periphery of the shaft 3a in the present embodiment. A metal metal housing 8 is provided inside the bracket housing 5e, that is, on the shaft 3a side with respect to the bracket housing 5e.

  As described above, by inserting the stator side protrusion 5a into the inner diameter of the frame 1 and positioning and fixing the bracket 5, the center of the housing 1a and the center of the metal housing 8 are aligned. . Further, the bearing 4 a (4) is held by the frame 1, and the bearing 4 b (4) is held by the bracket housing 5 e via the metal housing 8. That is, the frame 1 and the bracket housing 5e (metal housing 8) hold the shaft 3a via the bearings 4 (4a, 4b), respectively.

  The bracket 5 is formed with a through hole 5d through which the pin 2c (see also FIG. 5) is passed. The pin 2 c is embedded in the stator 2 and electrically connected to the substrate 9. The through holes 5d are formed in accordance with the embedding pitch of the pins 2c in the stator 2.

  The through hole 5d is formed so that its diameter decreases from the stator 2 side toward the substrate 9 side, and the clearance between the bracket 5 and the pin 2c is minimized on the substrate 9 side. In the through hole 5d, a moisture-proof treatment 10 having a quick drying property is applied to the entire gap between the pin 2c and the bracket 5 so as to suppress moisture ingress from the stator 2 side to the substrate 9 side after the pin 2c is penetrated. Applied.

  The substrate 9 is attached to the opposite side of the stator 2 side with respect to the bracket 5. The substrate 9 is bonded and fixed to the pins 2c penetrating the through holes 5d with solder or the like. As shown in FIGS. 4 and 7, the board 9 is mounted with electronic components 9a constituting a Hall IC 9b serving as rotor position detecting means, a drive circuit 9g for rotating the motor, a power supply circuit 9f, a microcomputer 9h, and the like. Yes.

  The substrate 9 is provided with aluminum radiating fins 9i for radiating heat generated from the electronic component 9a (see FIG. 1). The metal cover 6 is attached to the heat radiating fins 9i after the heat radiating sheet 11 having cushioning properties and the insulating sheet 12 having electrical insulating properties are attached.

  The cover 6 is fitted to the cover-side protrusion 5 b of the bracket 5. Further, as shown in FIG. 2, the frame flange 1b of the frame 1, the bracket flange 5c of the bracket 5, and the cover flange 6a of the cover 6 are aligned, and the cover protrusion 6b is inserted into the frame hole 1c. The frame 1, the bracket 5, and the cover 6 are fixed in a combined state.

  Screw holes 7 are provided in the bracket flange 5c, the frame flange 1b, and the cover flange 6a (see also FIG. 3), and the DC brushless motor 31 is screwed to a product such as a ventilation fan using the screw holes 7.

  The bracket 5 is made of resin. Since the bracket 5 is made of resin and has insulation, the creeping distance in the radial direction of the coil 2b, the pin 2c, the substrate 9, the frame 1, and the cover 6 can be secured. Further, in the axial direction, the coil 2b and the bracket 5 can be installed to the minimum until they contact each other, and the space between the substrate 9 and the bracket 5 can also be installed to the minimum until they come into contact with each other.

  Further, since the stator-side protrusion 5a of the bracket 5 is inserted into the inner diameter of the frame 1, the coaxiality between the metal housing 8 of the bracket 5 and the housing 1a of the frame 1 can be improved, and assembly can be performed with high accuracy.

  The bracket flange 5c can be easily fixed by sandwiching the bracket flange 5c between the frame flange 1b and the cover flange 6a and fixing the frame flange 1b and the cover flange 6a. In addition, since it is possible to suppress the stress of transport vibration and drop impact in the axial direction from being applied to the junction between the substrate 9 and the pin 2c and the substrate 9 itself, the junction between the substrate 9 and the pin 2c and the substrate 9 itself Quality deterioration can be suppressed.

  The through hole 5d formed in the bracket 5 has a diameter on the side of the stator 2 that is large and a diameter on the side of the substrate 9 is formed so as to minimize a gap with the pin 2c. Since the connecting space is provided, there is no possibility of damaging the coil 2b such as disconnection when the bracket 5 is installed.

  Since the bracket 5 is press-fitted into the inner diameter of the frame 1 and the moisture-proof treatment 10 is applied to the through hole 5d so as to eliminate the gap between the penetrating pin 2c, the space of the stator 2 and the rotor shaft 3 and the substrate 9 side Space can be separated. Therefore, it is possible to prevent moisture from entering the space on the substrate 9 side, and it is easy to avoid the substrate 9 from being damaged due to moisture, condensation, or the like.

  Since the moisture resistance performance on the electronic component 9a side is improved, the moisture-proofing treatment to other parts can be omitted or reduced, so that the working time and the number of steps for molding and potting can be reduced. Thereby, cost can be suppressed.

  By bringing the electronic component 9a into contact with the cover 6 via the heat radiating fins 9i, the heat radiating sheet 11 having cushioning properties, and the insulating sheet 12 having electrical insulation, the heat generated in the electronic component 9a can be reduced. Therefore, the temperature rise of the electronic component 9a can be suppressed.

  By making the frame hole 1c and the cover protrusion 6b press-fit, the frame 1 and the cover 6 can be reliably conducted by inserting the cover protrusion 6b into the frame hole 1c. Therefore, the grounding structure of the motor can be provided anywhere on the outer surface of the motor (the frame 1 and the cover 6), and the workability during product assembly is improved.

  Also, if the cover protrusion 6b is inserted into the frame hole 1c and then bent, the frame 1, the bracket 5, and the cover 6 can be fixed in a combined state. Can be planned. Of course, a hole may be formed on the cover 6 side, and a projection that matches the hole may be provided on the frame 1 side.

  In addition, the DC brushless motor 31 can be safely stopped because the substrate 9 is covered with the metal cover 6 even in an abnormality such as a failure due to a temperature rise of the electronic component 9a.

  As shown in FIG. 8, a commercial AC power supply 13 is supplied to the substrate 9 from the outside, the AC power supply is converted into a DC voltage by the power supply circuit 9f, and power is supplied at a voltage corresponding to each element.

  The drive circuit 9g generates an alternating voltage through the pin 2c (see also FIGS. 2 and 5) so that a current in a predetermined direction flows to the coil 2b provided in the stator 2. The rotor shaft 3 is rotated by the current flowing through the coil 2b.

  The microcomputer 9h detects the induced voltage phase of the motor based on the signal of the Hall IC 9b which is the rotor position detecting means, and performs control so that the induced voltage phase and the motor phase current phase generated from the drive circuit 9g are the same phase. Do. The efficiency of the motor can be maximized by making the induced voltage phase and the motor phase current phase the same phase.

  The drive circuit 9g performs sine wave drive so that the motor phase current becomes a sine wave. Sinusoidal driving reduces motor vibration. Therefore, even when used as a fan motor such as a duct ventilation fan, the product can be produced at low cost because the vibration-proof structure can be omitted or a light-weight vibration-proof structure can be employed in the product.

  As shown in FIG. 2, a recess 5p is formed around the through hole 5d on the surface of the bracket 5 on the substrate 9 side. The moisture-proof treatment 10 is formed by injecting a liquid moisture-proof material into the recess 5p with the pin 2c passing through the through-hole 5d of the bracket 5.

  By providing the recess 5p, it becomes easy to inject the moisture-proof material, and the workability when the moisture-proof treatment 10 is performed can be improved. Further, if the amount of moisture-proof material injected is suppressed to an amount that does not protrude from the recess 5p, when the substrate 9 is placed on the bracket 5, the moisture-proof material adheres to the substrate 9 or from the through hole 9k formed in the substrate 9. Can prevent seepage of moisture-proof material. Thereby, it becomes easy to ensure the quality of the solder joint between the substrate 9 and the pin 2c.

  As shown in FIGS. 3 and 7, the bracket 5 is provided with a substrate fixing base 5 m that fixes the substrate 9. The board fixing base 5m is provided with a screw hole 5n for fixing the board 9 using the board fixing screw 9j (see also FIG. 6).

  The substrate fixing base 5m is formed so as to protrude toward the substrate 9 from the surface on which the through hole 5d is formed. That is, the height H2 from the reference surface (see FIG. 7) is larger than the height H1 from the reference surface T of the bracket 5 (see FIG. 2). Thereby, when the board | substrate 9 is fixed to the board | substrate fixing stand 5m, a clearance gap is made between the through-hole 5d part of the bracket 5 and the board | substrate 9. FIG.

  Therefore, when the substrate 9 is disposed on the bracket 5, it is possible to further suppress the moisture-proof material from adhering to the substrate 9 and the moisture-proof material from leaking from the through holes 9 k formed in the substrate 9. Thereby, it becomes easier to ensure the quality of the solder joint between the substrate 9 and the pin 2c. For example, it is preferable to provide a gap of 0.5 mm or more between the through hole 5 d portion of the bracket 5 and the substrate 9. That is, it is preferable that H2−H1 ≧ 0.5 mm.

  In addition, since the assembly of the DC brushless motor 31 such as the placement of the substrate 9 can be advanced without waiting for the liquid moisture-proof material to dry, the processing time can be shortened. Thereby, cost can be suppressed.

  FIG. 9 is a partial enlarged cross-sectional view of a portion corresponding to a portion A shown in FIG. 1 in a conventional electric motor as a comparative example. As shown in FIG. 9, when a recess is not formed in the bracket 105 or when there is almost no gap between the peripheral portion of the through hole 105 d of the bracket 105 and the substrate 9, a moisture-proof material (moisture-proof material) The treatment 110) is likely to ooze out from the through hole 9k of the substrate 9. For this reason, the moisture-proof material that oozes out obstructs the solder joint between the substrate 9 and the pin 2c, making it difficult to ensure the quality of the solder joint.

  As described above, the electric motor according to the present invention is useful for a DC brushless motor, and is particularly suitable for a DC brushless motor attached to a ventilation fan.

1 frame 1a housing 1b frame flange 1c frame hole 2 stator 2a iron core 2b coil 2c pin 3 rotor shaft 3a shaft 3b rotor 4 bearing 5 bracket 5a stator side projection 5b cover side projection 5c bracket flange 5d through hole 5e bracket housing 5m board fixing base 5n Screw hole 5p Depression 6 Cover 6a Cover flange 6b Cover projection 7 Screw hole 8 Metal housing 9 Substrate 9a Electronic component 9b Hall IC (rotor position detection means)
9f Power supply circuit 9g Drive circuit 9h Microcomputer 9i Radiation fin 9j Substrate fixing screw 9k Through hole 10 Moisture-proof treatment 11 Heat radiation sheet 12 Insulation sheet 13 Commercial AC power supply 14 Spring 31 DC brushless motor (motor)
105 Bracket 105d Through-hole 110 Moisture-proof treatment B Arrow T Reference plane

Claims (4)

The stator,
A frame for accommodating the stator therein;
A rotor disposed inside the stator;
A shaft coupled to the rotor;
A bracket for rotatably holding the shaft;
A substrate disposed on the opposite side of the stator to the bracket;
A pin that is erected on the stator and electrically connects the stator and the substrate;
The bracket is formed with a through hole through which the pin passes and a substrate fixing base on which the substrate is placed and fixed ,
The periphery of the through hole of the bracket projects to the substrate side,
The electric motor according to claim 1, wherein the board fixing base is formed so as to protrude toward the board from a protruding portion around the through hole. 2. The electric motor according to claim 1, wherein a depression is formed around the through-hole and is formed around the through-hole. The through holes, the electric motor according to claim 1 or 2, characterized in that it is tapered in diameter toward the substrate side from the stator side is reduced. The bracket is electric motor according to any one of claims 1-3, characterized in that is made of resin.

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