JP2006060902A - Brushless motor with self-cooling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small and high-performance brushless motor with a self-cooling device wherein hindrance to output enhancement due to heating from winding or electronic components can be eliminated, and profound cooling effect on the winding and the electronic components can be obtained. <P>SOLUTION: A hole 19 is formed in the top face of a rotor frame 11, and a cut and raised portion 11a is formed inside the top face of the rotor frame. The end portion 11b of the cut and raised portion 11a in the axial direction is in such a shape that it is close to the outer shape 8a of winding 8 and has uniform intervals. Thus, profound cooling effect is obtained on the winding that is a heating element. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a brushless motor used for driving various mechanisms such as a copying machine and a laser beam printer, and more particularly to a structure of a cooling device for electronic components and motor windings arranged in the vicinity of the motor.

  2. Description of the Related Art Conventionally, a brushless motor having an electronic component disposed in the vicinity of a motor and a cooling device for a motor winding is known that uses cooling air from a self-cooling fan that rotates integrally with a rotor shaft. By setting the outer diameter of this self-cooling fan to be larger than the outer diameter of the rotor frame and arranging the electronic parts and the heat sink in the direct flow path of the air blown by the fan, not only the motor winding but also the electronic parts and the heat sink For example, a motor with a self-cooling fan that has a great cooling effect has been proposed (see, for example, Patent Document 1).

  FIG. 5 shows the structure of a conventional motor with a self-cooling fan described in Patent Document 1. In FIG. 5, reference numeral 1 denotes a housing which holds the bearings 2 and 3. A plate 4 holds the printed circuit board 5 and holds the housing 1 by caulking. 6 is a core, and a winding 8 is applied through an insulating layer 7 to constitute a stator. Reference numeral 9 denotes a screw that passes through the core 6 and is fastened to the housing 1 to fix the stator and the housing 1 in pressure contact. A rotor shaft 10 is press-fitted and fixed to the inner rings of the bearings 2 and 3 in which the outer ring is held in the housing 1 by press-fitting and fixing the rotor frame 11 that holds the magnet disposed in the outer circumferential direction of the core 6 with a gap. An electronic component 12 is fixed to the heat sink 14 with screws 13 and is mounted on the printed circuit board 5 together. A self-cooling fan 15 has an outer diameter larger than the outer diameter of the rotor frame 11 and is fixed to the rotor shaft 10.

In the brushless motor configured as described above, the winding generates heat in proportion to the magnitude of the current flowing in the winding, and the generated winding is cooled by cooling air from a self-cooling fan that rotates integrally with the rotor shaft. Cooling through the plate, the housing, the core, and the insulating layer can prevent an increase in temperature. Moreover, the outside diameter of the self-cooling fan 15 is made larger than the outside diameter of the rotor frame 11, and the electronic component 12 and the heat radiating plate 14 arranged on the outer periphery of the rotor are opposed to the self-cooling fan 15. An electronic component or a heat sink can be disposed in the direct flow path of the air, and a large cooling effect can be obtained for the electronic component or the heat sink.
JP-A-9-65632 (page 4, FIG. 1)

  However, in the above conventional configuration, the heat generated by the current flowing in the winding is indirectly cooled through the insulating layer, the core, the housing, and the plate by the cooling air generated by the self-cooling fan that rotates integrally with the rotor shaft. In order to suppress the rise, the cooling efficiency is low, and there is a problem that a larger current cannot be supplied to obtain a higher output.

  The present invention solves such a conventional problem, and an object thereof is to provide a small and high performance brushless motor capable of obtaining a large cooling effect.

In order to solve the above-mentioned problems, the present invention provides a brushless in which a field magnet is arranged at a position opposed to a cup-shaped rotor frame and a stator core on the inner periphery of the rotor frame and in a radial direction via a gap. The motor has a radial hole on the top surface of the rotor frame in the radial direction, and the top surface of the rotor frame is cut and raised inward, and the axial end shape of the cut and raised portion has a uniform interval from the outer shape of the winding. A configuration having a shape, or a configuration having a rotor frame provided with radial holes in the radial direction on the top surface and a cooling fan having a protrusion having the same shape as the cut and raised shape is characterized. .

  According to the first aspect of the present invention, radial holes are provided in the radial direction on the top surface of the rotor frame, and the top surface of the rotor frame is cut and raised inward so that the axial shape of the cut and raised end portions is evenly spaced from the windings. By having the shape with the air stirring at a position close to the winding, the heat generation of the winding can be suppressed by a very large cooling effect, and a larger current can flow to the motor. An advantageous effect that a small and high output brushless motor can be configured without a self-cooling fan is obtained.

  According to the second aspect of the present invention, a radial hole is provided in the radial direction on the top surface of the rotor frame, and a protrusion having the same shape as the cut and raised shape of the first aspect is provided on the self-cooling fan. Cooling the electronic components and heat sinks in the flow path, simultaneously cooling the windings in the direct flow path, and stirring the air at a position near the windings, a very large cooling effect can be obtained, making it compact The effect that a high output brushless motor can be constructed is obtained.

  According to the first aspect of the present invention, a field magnet is disposed at a position facing the radial direction through a gap between a cup-shaped rotor frame and a rotor core inner circumference and a winding provided with a stator core. A brushless motor, which has radial holes in the top surface of the rotor frame in the radial direction, cuts and raises the top surface of the rotor frame inward, and the axial end shape of the cut and lift has a uniform spacing from the outer shape of the winding. The winding as a heating element can be configured as a direct flow path of cooling air by making a hole in the top surface of the rotor frame, and a radial shape is formed on the top surface of the rotor frame. The rotor frame top surface is cut and raised inward, and the axial end shape of the cut and raised is shaped so as to have a uniform distance from the outer shape of the winding. It has a very large cooling effect on the windings by the agitation of the air in the stomach position.

  The invention according to claim 2 includes a rotor frame having radial holes on the top surface in the radial direction, and a self-cooling fan having a protrusion having the same shape as the cut and raised shape of claim 1. Forms a direct flow path to the wire and cools the winding by stirring air near the winding, and cools the electronic components and heat sinks in the flow path of the self-cooling fan Have

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a structural diagram showing a brushless motor according to Embodiment 1 of the present invention. FIG. 2 is a detailed view of a cut-and-raised portion of the top surface of the rotor frame in the first embodiment. Reference numeral 1 denotes a housing which holds the bearings 2 and 3. A plate 4 holds the printed circuit board 5 and holds the housing 1 by caulking. 6 is a core, and a winding 8 is applied through an insulating layer 7 to constitute a stator. Reference numeral 9 denotes a screw that passes through the core 6 and is fastened to the housing 1 to fix the stator and the housing 1 in pressure contact. A rotor shaft 10 is press-fitted and fixed to the inner rings of the bearings 2 and 3 in which the outer ring is held in the housing 1 by press-fitting and fixing the rotor frame 11 that holds the magnet disposed in the outer circumferential direction of the core 6 with a gap.

Further, by providing a hole 19 in the top surface of the rotor frame 11, a cooling air flow path 17 is formed, and a cut-and-raised portion 11a is provided on the top surface of the rotor frame 11 as shown in FIG. The end shape 11b in the axial direction of the cut-and-raised portion 11a has a shape that is close to the outer shape 8a of the winding 8 and has a uniform interval, so that air is stirred at a position close to the winding that is a heating element. Therefore, a large cooling effect can be obtained.

  In the motor with a self-cooling fan by the cut-and-raised portion 11a on the rotor frame top surface configured as described above, the winding 8 generates heat in proportion to the magnitude of the current flowing through the winding 8, and the generated winding 8 Is cooled by the cooling air by the self-cooling fan 11a that rotates integrally with the rotor shaft 10 through the rotor frame 11, the bearing 2, the housing 1, the core 6, and the insulating layer 7, thereby preventing an increase in temperature.

(Embodiment 2)
FIG. 3 is a structural diagram showing a brushless motor according to Embodiment 2 of the present invention. FIG. 4 is a detailed view of the self-cooling fan blade part of the brushless motor according to the second embodiment of the present invention. An electronic component 12 is disposed in the vicinity of the rotor frame, and is fixed to the heat radiating plate 14 with screws 13 and mounted together on the printed circuit board 5. Reference numeral 15 denotes a self-cooling fan, which is composed of a plurality of blades 15c formed radially from the axis of the rotating shaft as shown in FIG. 4, and a part of the blades 15a is formed from a hole 20 provided on the top surface of the rotor frame 11 through the rotor frame. The blade is inserted into the blade, and the blade end shape 15b in the axial direction is in the vicinity of the outer shape 8a of the winding 8 and has a uniform spacing.

  According to this embodiment, the hole 20 is provided in the top surface of the rotor frame 11 to form the cooling air flow path 17, and a part 15 a is inserted in the rotor frame into the self-cooling fan, Since the end shape 15b in the axial direction is in the vicinity of the outer shape 8a of the winding 8 and has a uniform interval, air agitation is performed at a position close to the winding, so that a great effect can be obtained in cooling the winding. In addition, the cooling air flow path 18 is formed by the blade 15c of the self-cooling fan, and the electronic component 12 and the heat radiating plate 14 are arranged in direct flow of the cooling air, so that the electronic component and the heat radiating plate are also very A large cooling effect can be obtained.

  The brushless motor with a self-cooling device according to the present invention has a cooling device for electronic parts and motor windings, and is useful as a small and high-output brushless motor for driving various mechanisms such as a copying machine and a laser beam printer. .

1 is a structural diagram showing a brushless motor according to a first embodiment of the present invention. FIG. 3 is a detailed view of the rotor frame top surface raising portion of the brushless motor according to the first embodiment of the present invention. Structure diagram showing a brushless motor according to a second embodiment of the present invention Detailed view of self-cooling fan blade part of brushless motor in Embodiment 2 of the present invention Structure of conventional brushless motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2, 3 Bearing 4 Plate 5 Printed circuit board 6 Core 7 Insulating layer 8 Winding 8a Winding outline 9, 13 Screw 10 Rotor shaft 11 Rotor frame 11a Cut-and-raised part of rotor frame top surface (self-cooling fan)
11b Cut-and-raised part of rotor frame top surface: shape of axial end part 12 electronic component 14 heat sink 15 self-cooling fan 15a rotor frame insertion part of self-cooling fan blade 15b rotor frame insertion part of self-cooling fan blade: shaft Directional end shape 15c Blade of self-cooling fan 16 Outer peripheral surface opening 17, 18 Cooling air flow path 19, 20 Hole in rotor frame top surface

Claims (2)

A brushless motor having a cup-shaped rotor frame, a rotor core inner periphery, and a stator core on which winding is applied, and a field magnet disposed at a position opposed to the radial direction via a gap, and having a diameter on the top surface of the rotor frame A brushless motor characterized in that radial holes are provided in the direction, the top surface of the rotor frame is cut and raised inward, and the axial end shape of the cut and raised has a shape having a uniform interval from the outer shape of the winding. . A brushless motor, comprising: a rotor frame having radial holes on a top surface in a radial direction; and a cooling fan having a protrusion having the same shape as the cut and raised shape of claim 1.