JPH0833279A - Brushless motor - Google Patents

Abstract

PURPOSE:To achieve excellent cooling effect by providing a fan secured to a rotor shaft and transmitting the heat generated from a winding to a plate through a core and housing thereby cooling the housing and plate. CONSTITUTION:A fan 12 is secured to a rotor shaft 6 and the heat generated from a winding 5 is transmitted through a core 3 and a housing 2 to a plate 1 thus cooling the housing 2 and plate 1 with cooling air fed from the fan 12 rotating integrally with the rotor shaft 6 and preventing temperature rise of the winding 5. Since an excellent cooling effect is achieved and a high current can be fed to the winding 5 in order to produce high output, a high performance small brushless motor can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to P. P. The present invention relates to the structure of a brushless motor used in office automation equipment such as C and printers.

[0002]

2. Description of the Related Art In recent years, P. P. C, O such as printer
Equipment A tends to be highly functional and miniaturized according to user needs, and inexpensive products are demanded by personalization.

Under such market conditions, a brushless motor used as a drive source for OA equipment is required to have high output, small size and low price.

The structure of a conventional brushless motor will be described below. FIG. 5 shows the structure of a conventional brushless motor. In FIG. 5, reference numeral 2 is a housing which holds the bearings 13 and 14. A plate 51 holds the printed circuit board 9 and the housing 2 by crimping. A core 3 is provided with a winding 5 through an insulating layer 4 to form a stator. A screw 10 penetrates the core 3 and is fastened to the housing 2 to press and fix the stator and the housing 2 together. A rotor shaft 6 is press-fitted and fixed to a rotor frame 7, which has magnets bonded and held in the outer circumferential direction of the core 3 with a gap therebetween, and is bonded and fixed to inner rings of bearings 13 and 14 having outer rings held in the housing 2. . Reference numeral 8 denotes an electronic component, which is mounted on the printed circuit board 9 by being pressed and fixed to the heat sink 15 with a screw 11.

The operation of the brushless motor constructed as above will be described below. First, a current is supplied to the winding through an electronic component mounted on the printed board, and a magnetic field is generated in the core having the winding by electromagnetic action. A repulsive force and an attractive force are generated between this magnetic field and the magnetic field of the magnet arranged to face the core, and the rotor frame holding the magnet rotates integrally with the rotor shaft. Also, the electronic components and the windings in the current passage generate heat in proportion to the magnitude of the current. The heat generated in the electronic component is radiated through the heat radiating plate pressed against the electronic component, and the heat generated in the winding is radiated from the plate through the housing and the rotor frame through the housing, the bearing and the rotor shaft. .

[0006]

However, in the above-mentioned conventional structure, the surface area of the housing is limited, and the size of the heat radiation plate that is pressed against the electronic parts is also limited. There was a problem that the electric current could not be passed.

The present invention solves the above problems,
An object of the present invention is to provide a small-sized and high-performance brushless motor capable of obtaining a large cooling effect by a fan.

[0008]

In order to achieve this object, a brushless motor of the present invention is provided with a core provided with windings, and a notch or hole for holding the core through a housing and being within the core diameter. A plate and a fan fixed to the rotor shaft by arranging the plate and the plate through a gap, and the electronic component is fixed between the fan and the plate.

[0009]

With this configuration, the windings that generate heat are directly cooled by the cooling air from the fan fixed to the rotor shaft through the passage formed in the plate. Further, the heat generated by the electronic components arranged within the rotor diameter is also efficiently conducted to the plate and cooled by the fan fixed to the rotor shaft.

[0010]

【Example】

(Embodiment 1) Hereinafter, first and second embodiments of the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 2 is a housing which holds the bearings 13 and 14. Reference numeral 1 denotes a plate that holds the printed circuit board 9 and the housing 2 by crimping. A core 3 is provided with a winding 5 through an insulating layer 4 to form a stator. Reference numeral 10 denotes a screw, which penetrates the core 3 and is fastened to the housing 2 to press and fix the stator and the housing 2 together. Reference numeral 6 denotes a rotor shaft, which is press-fitted and fixed to a rotor frame 7 in which magnets are bonded and held in the outer peripheral direction of the core 3 with a gap therebetween, and is fixed to inner rings of bearings 13 and 14 having outer rings held in the housing 2. Reference numeral 8 denotes an electronic component, which is mounted on the printed circuit board 9 by being pressed and fixed to the heat sink 15 with a screw 11. A fan 12 is fixed to the rotor shaft 6.

In the brushless motor configured as described above, the winding heats in proportion to the magnitude of the current flowing in the winding, and the generated heat is conducted to the plate through the core and the housing, and is integrated with the shaft. The cooling air from the fan that rotates in the direction cools the housing and plate, preventing the temperature of the winding from rising.

In FIG. 2, the plate 1 and the printed circuit board 29 are partially cut away so that the core 3, the winding 5 and the fan 12 partially face each other. A large cooling effect can be obtained by cooling and blowing air to the winding and the core.

(Second Embodiment) A third embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, reference numeral 2 denotes a housing, which is a bearing 1.
Hold 3 and 14. 1 is a plate, which is a printed circuit board 9
And the housing 2 is held by crimping. Three
Is a core, and a winding 5 is provided through the insulating layer 4 to form a stator. Reference numeral 10 denotes a screw, which penetrates the core 3 and is fastened to the housing 2 to press and fix the stator and the housing 2 together. Reference numeral 6 is a rotor shaft, which is a rotor frame 7 in which magnets are bonded and held in the outer circumferential direction of the core 3 with a gap therebetween.
Bearing 1 in which the outer ring is held in the housing 2
It is adhesively fixed to the inner rings of 3 and 14. An electronic component 8 is fixed to the plate 1 with a screw 11 and mounted on the printed board 9. A fan 12 is fixed to the rotor shaft 6.

In the brushless motor constructed as described above, the electronic components generate heat in proportion to the magnitude of the current flowing in the winding, and the generated heat is radiated through the plate,
Further, a large cooling effect can be obtained by blowing air with a fan that rotates integrally with the shaft.

(Embodiment 3) A fourth embodiment of the present invention will be described below with reference to the drawings.

In FIG. 4, a housing 42 holds the bearings 13 and 14. The housing 42 holds the printed circuit board 9. A core 3 is provided with a winding 5 through an insulating layer 4 to form a stator. Reference numeral 10 denotes a screw which penetrates the core 3 and is fastened to the housing 42 to press and fix the stator and the housing 42. Reference numeral 6 denotes a rotor shaft, which is press-fitted and fixed with a rotor frame 7 to which a magnet arranged and held in the outer peripheral direction of the core 3 with an air gap is press-fitted and fixed.
The outer races are adhered and fixed to the inner races of the bearings 13 and 14. Reference numeral 8 denotes an electronic component, which is mounted on the printed circuit board 9 by being pressed and fixed to the heat sink 15 with a screw 11. A fan 12 is fixed to the rotor shaft 6.

In the brushless motor configured as described above, the winding heats up in proportion to the magnitude of the current flowing through the winding, and the generated heat is conducted to the housing through the core and rotates integrally with the shaft. The cooling air from the cooling fan cools the housing and prevents the temperature of the winding from rising.

[0020]

As described above, according to the present invention, the core provided with the winding wire, the plate holding the core through the housing and provided with the notch or hole within the core diameter, and the plate and the gap are provided. And a fan fixed to the rotor shaft and having electronic components fixed between the fan and the plate, the cooling air from the fan cools the housing and the plate, and the winding and the electronic component. A large cooling effect can be obtained because it is directly cooled, and by integrally forming the housing and the plate, the thermal resistance between the cooling section and the winding by the fan can be reduced and a greater cooling effect can be obtained. It is possible to realize an excellent brushless motor capable of passing a larger current in order to obtain an output.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a partial sectional view of a brushless motor according to a second embodiment of the present invention.

FIG. 3 is a partial sectional view of a brushless motor according to a third embodiment of the present invention.

FIG. 4 is a partial sectional view of a brushless motor according to a fourth embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a brushless motor according to a conventional example.

[Explanation of symbols]

 1,51 Plate 2,42 Housing 3 Core 4 Insulating Layer 5 Winding 6 Rotor Shaft 7 Rotor Frame 8 Electronic Parts 9,29 Printed Circuit Board 10,11 Screw 12 Fan 13,14 Bearing 15 Heat Radiator

Claims (4)

[Claims] 1. A core provided with a winding, a plate for holding the core via a housing, and a fan fixed to the rotor shaft, the fan being arranged via the plate and a gap. Brushless motor. 2. The brushless motor according to claim 1, wherein the plate is provided with a notch or a hole extending within the core diameter, and a flow passage means for cooling air from the fan to the winding is formed. 3. The brushless motor according to claim 1, wherein the fan has a function of cooling the electronic component fixed to the plate. 4. The brushless motor according to claim 1, wherein the housing and the plate are integrally formed.