JPH0865943A - Motor - Google Patents

Abstract

PURPOSE: To provide a motor which reduces the heat conducted from a rotor core to a bearing to suppress the temperature rise of the bearing, and is excellent in the durability. CONSTITUTION: In a motor provided with a shaft 1, a rotor core 4 press-fitted to this shaft 1, and bearings 5, 6 to support each side part of this shaft 1, a wedge-shaped projection 8 is formed on the surface of the shaft between the bearing 6 and the rotor core 4. Thus, the diameter of the reduced, and the temperature rise of the bearing 6 due to the heat conduction from the rotor core 4 to realize a motor which is excellent in the durability and high in the reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor having a bearing thrust receiving structure.

[0002]

2. Description of the Related Art FIG. 4 shows a thrust receiving structure of a conventional motor. The surface of the shaft 1 is provided with two knurled parts 2 and 3. One of the knurled portions 2 is press-fitted into the rotor core 4 and transmits the rotational force to the shaft 1. The other knurl portion 3 regulates the position of one bearing 5 such as a bearing in the thrust direction and holds the thrust load. Normally, two bearings 5 and 6 are required. Therefore, with respect to the bearing 6 on the opposite shaft press-fitting side, a thrust pipe 7 or the like is inserted between the bearing 6 and the rotor core 4 to regulate the position and maintain the thrust load. It was structured to do.

[0003]

In order to miniaturize the motor, it is necessary to make the dimensions between the bearings 5 and 6 as short as possible. However, in the conventional structure, when the dimension between the bearings is shortened, the distance from the rotor core 4, which is a heat source of the motor, is reduced, and the thrust pipe 7 is inserted to hold the bearing, so that the bearing diameter is reduced. There is a problem in that the heat generation from the rotor core 4 is substantially increased, the heat is easily transmitted to the bearing 6, the bearing temperature is increased, and the durability performance is reduced. Especially when the motor is downsized, the distance between the rotor core and the bearing is shortened, so that the temperature of the bearing is apt to increase significantly.

Therefore, an object of the present invention is to provide a motor having a structure capable of holding a bearing without increasing the shaft diameter and reducing heat conduction from the rotor core.

[0005]

To this end, according to the present invention, a wedge-shaped projection is formed on the surface of the shaft between the bearing and the rotor core to regulate the position of the bearing and hold the thrust load. It is a thing.

[0006]

According to the above construction, the thrust pipe conventionally inserted for holding the bearing becomes unnecessary, and the shaft diameter between the rotor core and the bearing can be substantially reduced. Therefore, the temperature rise of the bearing due to heat conduction from the rotor core can be suppressed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a motor according to an embodiment of the present invention,
FIG. 2 is a sectional view of a wedge-shaped protrusion on the shaft of the motor, FIG.
FIG. 3 is a perspective view of a shaft of the motor.

In FIG. 1, two knurls 2 and 3 are formed on the surface of the shaft 1. One knurled portion 2 is press-fitted into the center of the rotor core 4, and the other knurled portion 3 is press-fitted with one bearing 5.
Here, the outer diameter of the one knurled portion 2 is slightly larger (about 20 μm) than the inner diameter of the rotor core 4, but the outer diameter of the other knurled portion 3 is considerably large (about 600 μm).
μm) large. Therefore, the press-fitting is performed from the one knurl portion 2 side.

After press-fitting the shaft 1 into the rotor core 4, the bearing 6
A wedge-shaped protrusion 8 is formed on the surface of the shaft 1 between the rotor core 4 and the rotor core 4. FIG. 2 shows a state in which a wedge-shaped projection 8 is formed on the surface of the shaft 1 by a rolling process using a jig 9, and FIG. 3 shows the shaft 1 after the wedge-shaped projection 8 is formed. .

The wedge-shaped projection 8 controls the position of the bearing 6 and holds the thrust load, but the diameter of the shaft 1 does not substantially increase as compared with the conventional example shown in FIG. The heat conduction from the rotor core 4 is small, and the temperature rise of the bearing 6 can be suppressed.

[0011]

As described above, according to the present invention, the wedge-shaped projection is formed on the surface of the shaft between the bearing and the rotor core to regulate the position of the bearing and hold the thrust load. The thrust pipe conventionally inserted for holding the bearing becomes unnecessary, and the shaft diameter between the rotor core and the bearing can be substantially reduced. Therefore, the temperature rise of the bearing due to heat conduction from the rotor core can be suppressed, and a highly reliable and highly reliable motor can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view of a motor according to an embodiment of the present invention.

FIG. 2 is a machining cross-sectional view of a wedge-shaped protrusion on a shaft of a motor according to an embodiment of the present invention.

FIG. 3 is a perspective view of a shaft of a motor according to an embodiment of the present invention.

FIG. 4 is a thrust receiving structure diagram of a conventional motor

[Explanation of symbols]

 1 axis 4 rotor core 5,6 bearing 8 wedge-shaped protrusion

Claims (1)

[Claims] 1. A shaft and a rotor core press-fitted into the shaft,
A motor provided with a bearing for bearing both side portions of the shaft, wherein a wedge-shaped projection is formed on a surface of the shaft between the bearing and the rotor core.