JPH0965632A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool a brushless motor with a self-cooling fan having an outside diameter larger than that of a rotor frame by providing a function that cools a plate holding a core which is press-contacted with the plate through a housing and electronic parts which are press-contacted with and fixed to a heat radiating plate. SOLUTION: A self-cooling fan 12 has an outside diameter larger than that of a rotor frame 7 and is fixed to a rotor shaft 6. A winding 5 generates heat proportionally to the magnitude of the electric current flowing through the winding 5 and the generated heat is transmitted to a housing 2 and a plate 1 through a core 3. Since the housing 2 and plate 1 are cooled by cooling air blown from a self-cooling fan 12 which rotates integrally with the shaft 6, the temperature rise of the winding 5 can be prevented. In addition, since the outside diameter of the fan 12 is made larger than that of the frame 7 and electronic parts 8 and a heat radiating plate 15 arranged on the outer periphery of a rotor are faced to the fan 12, the parts 8 and plate 15 can be arranged in the direct passage of the air flow generated by the fan 12.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, P.I. P. C. , Printers, etc.
Equipment A tends to be highly functional and miniaturized according to user needs, and inexpensive products are demanded by personalization. Under such market conditions, the brushless motor used as a drive source for OA equipment has a high output,
Small, low-priced products are required.

[0003] The structure of a conventional brushless motor will be described below. FIG. 3 shows the structure of a conventional brushless motor. In FIG. 3, reference numeral 2 denotes a housing which holds the bearing 13 and the bearing 14. A plate 1 holds the printed circuit board 9 and holds the housing 2 by caulking. 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 fix the stator and the housing 2 by pressure. Reference numeral 6 denotes a rotor shaft, which is press-fitted and fixed to a rotor frame 7 in which a magnet wired and held in the outer peripheral direction of the core 3 through an air gap is adhered and fixed, and is fixed to inner rings of a bearing 13 and a bearing 14 in which a housing 2 holds an outer ring. . 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 configured as described 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 repulsion and an attractive force are generated between the magnetic field and the magnetic field of the magnet arranged facing 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. .

[0005]

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 in pressure contact with the electronic parts is also limited. There was a problem that a large current could not flow.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a small-sized and high-performance brushless motor which can obtain a large cooling effect by a self-cooling fan.

[0007]

In order to achieve this object, a brushless motor of the present invention comprises a plate in which a core is pressed and held through a housing by a self-cooling fan having an outer diameter larger than that of a rotor frame. , Has a configuration having a function of cooling an electronic component that is fixed in pressure contact with a heat sink. Further, by fixing the self-cooling fan to the top surface of the rotor frame, a thin motor having a cooling function is provided.

[0008]

With this structure, air generated by the self-cooling fan flows in the heat generated in the winding, and the plate in the flow path is cooled. In addition, a large cooling effect can be obtained by disposing the electronic component in the flow path of the cooling air directly from the self-cooling fan on the outer circumference of the rotor.

[0009]

【Example】

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

In FIG. 1, reference numeral 2 denotes a housing, which is a bearing 13.
And holding the bearing 14. A plate 1 holds the printed circuit board 9 and holds the housing 2 by caulking.
A core 3 is provided with a winding 5 through an insulating layer 4 to form a stator. Reference numeral 10 denotes a screw. The core 3 penetrates and is fastened to the housing 2 to fix the stator and the housing 2 by pressure. Reference numeral 6 denotes a rotor shaft, which is a bearing 1 in which a rotor frame 7 having a magnet arranged and bonded in the outer circumferential direction of the core 3 with an air gap adhered thereto is press-fitted and fixed, and an outer ring is held in a housing 2.
3 and the inner ring of the bearing 14 are fixed by adhesion. 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 self-cooling fan 12 has an outer diameter larger than that of the rotor frame 7 and 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 radiated through the core, and the housing and plate are integrated with the shaft. The plate can be cooled by blowing air with a self-cooling fan that rotates at, and the temperature rise of the winding can be prevented.

Further, the outer diameter of the self-cooling fan 12 is larger than that of the rotor frame 7, and the self-cooling fan 12 faces the electronic components 8 and the heat radiating plate 15 arranged on the outer periphery of the rotor. It is possible to arrange the electronic components and the heat dissipation plate in the direct flow path of air blown by the fan, and it is possible to obtain a great cooling effect.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, reference numeral 2 denotes a housing, which is a bearing 13.
And holding the bearing 14. A plate 1 holds the printed circuit board 9 and holds the housing 2 by caulking.
A core 3 is provided with a winding 5 through an insulating layer 4 to form a stator. Reference numeral 10 denotes a screw. The core 3 penetrates and is fastened to the housing 2 to fix the stator and the housing 2 by pressure. Reference numeral 6 denotes a rotor shaft, which is a bearing 1 in which a rotor frame 7 having a magnet arranged and bonded in the outer circumferential direction of the core 3 with an air gap adhered thereto is press-fitted and fixed, and an outer ring is held in a housing 2.
3 and the inner ring of the bearing 14 are fixed by adhesion. An electronic component 8 is fixed to the plate 1 with a screw 11 and mounted on the printed board 9. Reference numeral 12 denotes a self-cooling fan having an outer diameter larger than that of the rotor frame 7 and fixed to the rotor frame 7.

In the brushless motor configured as described above, the electronic components generate heat in proportion to the magnitude of the current flowing through the windings, and the electronic components and the heat sink are arranged in the direct flow path of the air blown by the self-cooling fan. By doing so, a large cooling effect can be obtained.

Further, the self-cooling fan 12 is connected to the rotor frame 7
By fixing to the top surface of No. 2, the fitting portion size 12a in the configuration for fixing the self-cooling fan to the rotor shaft as in the first embodiment of the present invention is unnecessary, and a thin motor with a large cooling effect is constructed. be able to.

[0017]

As described above, the present invention is provided with the self-cooling fan fixed to the rotor shaft and having an outer diameter larger than the outer diameter of the rotor frame and arranged via the air gap with the rotor frame. As a result, the cooling air from the self-cooling fan cools the windings through the plate and directly cools the electronic components, so that a large cooling effect can be obtained, and a larger current can be passed to obtain a high output. It is possible to realize an excellent brushless motor that can be realized. In addition, since a self-cooling fan fixed to the top surface of the rotor frame with an outer diameter larger than the outer diameter of the rotor frame is provided, a greater cooling effect can be obtained, and it is possible to realize a thin brushless motor with high output. is there.

[Brief description of drawings]

FIG. 1 is a structural diagram of a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a structural diagram of a brushless motor according to a second embodiment of the present invention.

FIG. 3 is a structural diagram of a conventional brushless motor.

[Explanation of symbols]

 1 Plate 2 Housing 3 Core 4 Insulating Layer 5 Winding 6 Rotor Shaft 7 Rotor Frame 8 Electronic Component 9 Printed Circuit Board 10, 11 Screw 12 Self-Cooling Fan 12a Self-Cooling Fan Fitting Size 13, 14 Bearing 15 Heat Sink

Claims (2)

[Claims] 1. A self-cooling fan having an outer diameter larger than that of a rotor frame fixed to the rotor shaft, the rotor frame being disposed through a gap with the rotor frame, and being fixed to the rotor shaft. Brushless motor. 2. A brushless motor comprising a self-cooling fan having an outer diameter larger than that of the rotor frame and fixed to the top surface of the rotor frame.