JP6255566B2 - Electric motors and electrical equipment - Google Patents

Description

  The present invention relates to an electric motor having an enhanced cooling effect for electronic components provided in the electric motor and an electric device including the electric motor.

  Conventionally, an electric motor with a built-in motor drive circuit generates heat by the power consumed by the power switching element, which is the motor drive element, and when the amount of heat generation increases, the temperature rise of the element reaches a limit value. There is a problem that the overheat protection device works due to heat generation, the function of the element itself stops, and the function of the motor stops.

  In order to solve this problem, heat generated by the power switching element is dissipated through a heat conductive resin to an iron bracket located opposite to the circuit board to which the element is attached (see, for example, Patent Document 1). ).

  FIG. 5 shows a structural cross-sectional view of a conventional molded electric motor. The stator core 1 is provided with a winding 3 via a stator insulator 2 to constitute a stator core winding assembly (no reference numeral). The stator core winding assembly is integrally formed with resin 5 together with the shaft-out bracket 4 to form a structure of a molded electric motor. A magnet 7 and a rotor 7 are integrally formed on the rotor core 8 to form a rotor structure, which is press-fitted and fixed to the shaft 6, and bearings 10 are provided at both ends of the shaft 6.

  Place the rotor assembly (no sign) in the molded stator core winding assembly, and place the circuit board 11 on which various electronic parts such as the motor driver IC and electrolytic capacitor are soldered and mounted. The side bracket 14 is attached to complete the electric motor. Note that electronic parts such as a brushless motor driver IC and an electrolytic capacitor are not shown.

  In FIG. 5, the conventional molded motor does not mold the circuit board 11 on which electronic components such as a driver IC of the motor and an electrolytic capacitor are soldered and mounted, so that the motor has a stator core winding assembly, The circuit board 11, the rotor, the anti-axial bracket 14, and these components can be disassembled.

Further, since the circuit board 11 on which electronic components such as a motor driver IC and an electrolytic capacitor are soldered and mounted is not sealed with the resin 5, the internal stress of the resin 5 is not applied. As shown in FIG. 5, the stator core winding assembly which is molded, the pre SL rotor and the circuit board 11, after placed in stator core winding assembly which is molded, axially opposite the delivery side In this structure, the bracket 14 is attached to the opposite axis output side of the molded stator core winding assembly.

  When disassembling the molded motor, the circuit board 11 and the rotor assembly can be easily taken out by removing the non-axis output side bracket 14, so that the anti-axis output side bracket 14, the circuit board 11, and the rotor are removed. Disassembly for assembly is very simple.

  Next, the connection between the circuit board 11 and the stator core assembly will be described in detail. The stator insulator 2 that is a constituent element of the stator core winding assembly is provided with a protrusion for fixing the mounting board in advance, and when the stator core winding assembly is molded, the board fixing protrusion is not provided. Molding is performed so as to be exposed from the resin.

  When the circuit board 11 is attached, the board fixing protrusion is inserted into a mounting hole provided in the circuit board 11 in advance, and the tip of the board fixing protrusion protruding from the attachment hole is heated. By deforming flatly, the circuit board 11 can be easily fixed to the stator core winding assembly. A thermoplastic resin is used for the stator insulator 2.

  The stator insulator 2, which is a component of the stator core winding assembly, is provided in advance with a connection terminal for winding to which the winding 3 is connected, and when the stator core winding assembly is molded, the winding Molding is performed so that the line connection terminals are exposed from the resin 5. When the circuit board 11 is attached, the winding connection terminals are inserted into the connection holes provided in the circuit board 11 in advance. The circuit board 11 and the winding 3 can be electrically connected very easily by soldering the tip of the connecting terminal for winding projecting from the part and the land around the connection hole of the circuit board 11. The winding connection terminal has conductivity.

  Although the material of the resin 5 was not specified, by not molding the circuit board 11, there is no temperature restriction due to various electronic components such as a motor driver IC mounted by soldering on the circuit board 11, and the molding temperature is compared. It is possible to use not only a low thermosetting resin but also a thermoplastic resin having a high molding temperature. Either a thermosetting resin or a thermoreversible resin is possible.

  Other than the above-described electric motor, there is an electric motor having a structure in which air is circulated to cool electronic components by attaching a fan directly to the shaft (see, for example, Patent Document 2).

JP 2007-6603 A JP 2010-93987 A

  The former conventional electric motor is excellent because it has a large industrial value. However, when the fan load increases and the motor winding current increases accordingly, it is consumed by the control-driven power switching element 12. As a result, more power is generated, and the amount of heat generated by the control-driven power switching element 12 becomes larger. As a result, the heat radiation effect from the control-driven power switching element 12 to the iron bracket via the resin has been insufficient.

  For this reason, according to Patent Document 1, in the conventional electric motor, there is also a configuration in which a heat radiation fin is further added to the outside air surface side of the bracket to reduce the heat resistance of heat radiation. However, since the bracket is interposed between the control-driven power switching element and the heat radiating fin, the bracket is a thermal resistance layer.

  Furthermore, a thermal resistance layer is also generated at the boundary surface between the control-driven power switching element and the bracket, and a thermal resistance layer is also generated at the boundary surface between the bracket and the radiating fin. Therefore, there is a problem that there is a limit in reducing the thermal resistance of heat dissipation.

  In addition, when the bracket and the radiating fin are integrated, the material is either a material suitable for the bracket or a material suitable for the radiating fin, so there is a problem in either mechanical strength or thermal resistance. Has occurred. Furthermore, in the structure in which the bracket and the heat radiating fin are integrated, an increase in manufacturing cost for satisfying the dimensional accuracy condition is caused and the industrial value becomes poor.

  Moreover, in the latter patent document 2, since it is necessary to ensure the installation space of a fan inside an electric motor, the physique of an electric motor will become large. Moreover, it has the subject that a new part and man-hour increase by attaching a fan.

In order to solve the above problems, an electric motor of the present invention includes a stator including a stator core around which a winding is wound, a rotating body facing the stator and holding a plurality of magnets in a circumferential direction, A rotor including a shaft fastened to the rotating body so as to pass through the center of the rotating body; a bearing that supports the shaft; a bracket that fixes the bearing; and the bracket on the stator and the non-axial side And an electronic component mounted on the surface thereof includes a circuit board facing the bracket , and protrudes in an axial direction on the end face of the rotor on the side on which the circuit board is mounted, and has a radius A plurality of protrusions extending in the direction are provided.

  By rotating the rotor, these protrusions can agitate the air inside the electric motor and increase the cooling effect of the electronic components mounted on the circuit board.

  According to the electric motor of the present invention, it is possible to suppress the temperature rise of the electronic component by cooling the electronic component such as the power switching element.

Sectional drawing of the electric motor in Embodiment 1 of this invention Perspective view of rotating body of same motor The perspective view of the rotary body of the electric motor in Embodiment 2 of this invention Schematic of an outdoor unit of an air conditioner equipped with the electric motor of the present invention Cross section of conventional motor

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of an electric motor according to Embodiment 1 of the present invention. First, a stator in which a winding 3 is applied to a stator core 1 via a stator insulator 2 and a protruding side bracket 4 for fixing a protruding side bearing 10 are molded with a resin 5. .

  A rotor core 8 formed by laminating high permeability iron plates on an iron shaft 6 is press-fitted and fixed to constitute a rotor. The rotating body holds a plurality of magnets 7 in the circumferential direction of the outer periphery and is molded with a resin 9.

  Then, the rotor is inserted with a small gap from the stator core 1, and the rotor shaft 6 is fixed to the bearing 10 on the axis-exit side and the other axis-exit-side bracket 14. It is held by a bearing.

  The circuit board 11 is attached between the counter-axis protruding bracket 14 and the stator.

  Further, the surface of the power switching element 12 on the circuit board 11 is in contact with the non-axis-projecting side bracket 14 via the heat conductive resin 13.

When a current is passed through the winding 3, the power switching element 12 itself generates heat due to the power consumed by the power switching element 12. The heat from the power switching element 12 is transmitted to the heat conductive resin 13, and is transmitted to the non-axis exit side bracket 14 in contact with the heat conductive resin 13. Since the non-axis exit side bracket 14 constitutes an outer shell of the electric motor, the heat generated from the power switching element 12 as a heat source is finally emitted from the counter axis exit side bracket 14 into the outside air.

  Next, details of the rotating body will be described with reference to FIG. On the end surface of the rotating body on the side of the circuit board 11, a protrusion 15 that protrudes in the axial direction with the resin 9 is formed. The protrusion 15 has a shape extending radially in the radial direction.

  When a current is passed through the winding 3, the rotor rotates, and the air inside the motor is agitated by the projection 15, and at the same time, the electronic components mounted on the circuit board 11 are cooled. Compared to the conventional structure, the heat dissipation effect of the power switching element 12 is increased, and the overheat protection device does not work even with a higher load, so that the function of the motor is not impaired.

  Table 1 shows the temperature rise value of each part when the electric motor of the embodiment of the present invention and the electric motor of the conventional example are mounted on an air conditioner. The locations where the temperature rise is observed are the circuit board mounting solder portion of the power switching element 12 and the winding 3 in addition to the power switching element 12.

  From this result, it can be confirmed that in the present invention, not only the temperature of the power switching element 12 but also the temperature of the circuit board mounting solder portion of the power switching element 12 is lowered as compared with the conventional structure.

(Embodiment 2)
If the rotation direction of the electric motor is always constant, the projection 15 formed on the end surface in the axial direction of the rotor, as shown in FIG. It is possible to increase the cooling effect of the electronic components. Here to the fan rotation direction 108, it is shaped to curved concave shape. The protrusion 109 may have a wing shape.

(Embodiment 3)
FIG. 4 is a schematic diagram showing the configuration of an outdoor unit of an air conditioner equipped with the electric motor of the present invention. An electric motor 101 is attached to an electric motor mounting plate 102 in the casing 100 of the outdoor unit, and a propeller fan 103 is attached to the shaft tip. An electric motor drive device 105 is positioned on a compressor 104 located in a separate room from the electric motor 101. The electric motor drive device 1
The electric motor 101 is driven by energization from 05, and the propeller fan 103 rotates accordingly.

  The heat exchanger 106 is cooled by the rotation of the propeller fan 103. Since the blowing direction 107 of the propeller fan 103 is always a constant direction, the fan rotation direction 108 of the electric motor 101 is always a constant direction.

  As described above, according to the present invention, since the cooling effect of the built-in electronic components is improved, the present invention can be applied to all electric motors incorporating electronic components and circuit boards.

DESCRIPTION OF SYMBOLS 1 Stator iron core 2 Stator insulator 3 Winding 4 Axial bracket 5 and 9 Resin 6 Shaft 7 Magnet 8 Rotor iron core 10 Bearing 11 Circuit board 12 Power switching element 13 Thermal conduction resin 14 Anti-axial rail 15 109 Protrusion 100 Housing 101 Motor 102 Motor Mounting Plate 103 Propeller Fan 104 Compressor 105 Motor Drive Device 106 Heat Exchanger 107 Blowing Direction 108 Fan Rotation Direction

Claims (8)

A stator including a stator core wound with windings;
A rotor including a rotating body facing the stator and holding a plurality of magnets in the circumferential direction; and a shaft fastened to the rotating body so as to penetrate the center of the rotating body;
A bearing that supports the shaft;
A bracket for fixing the bearing;
Located between the stator and the bracket on the non-axial side, an electronic component mounted on the surface thereof includes a circuit board facing the bracket ,
An electric motor in which a plurality of protrusions protruding in an axial direction and extending in a radial direction are provided on an end face of the rotor on a side where the circuit board is attached. The electric motor according to claim 1, wherein the electronic component is in contact with the bracket via a heat conductive resin. The electric motor according to claim 1, wherein at least a part of the stator is covered with resin. The plurality of protrusions generates an air flow that cools the circuit board by stirring the air between the rotor and the bracket when the rotor rotates . The electric motor according to any one of the above. The electric motor according to any one of claims 1 to 4 , wherein the protrusion is curved in a convex shape toward the opposite side of the direction in which the rotor rotates . The protrusion together with the magnet electric motor according to any one of claims 1 to 5, characterized in that it is molded in resin. The stator core is an electric motor according to any one of claims 1 to 6, characterized in that is obtained by laminating the high-permeability iron plate. The electric motor according to any one of claims 1 to 7 ,
An electric motor driving device for driving the electric motor;
Electric equipment equipped with.

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