JPH0670504A - Bearing for motor - Google Patents

Abstract

PURPOSE:To make it possible to correct a deviation in bearing load and provide a longer operating life by contacting together two or more independent oil- containing slide bearings and purposely giving an adequate deviation to the degree of holes. CONSTITUTION:In the case of a bearing for an axial fan motor, a rotor frame 7 and a shaft 1 rotate by the magnetic repulsion between a stator 8 and a field magnet 9, and an oil film pressure due to outgoing oil occurs between a shaft 1 and oil-containing slide bearings 21 and 31. Then, a deviation is created in oil consumption due to the size of bearing loads between the oil-containing slide bearing 21 at the rotor frame side and the oil-containing slide bearing 31 at the counter-rotor frame side. At this time, the degree of holes of the oil containing slide bearing 21 having a higher oil consumption rate is made smaller than the degree of holes of the oil-containing slide bearing 31, so that capillary phenomenon occurs between the two contact surfaces, and oil of the slide bearing 31 having a lower oil consumption rate is absorbed to open holes of the oil-containing slide bearing 21 and supplied for lubrication the bearing at the higher load side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a motor used in various office (OA) equipment.

[0002]

2. Description of the Related Art In recent years, cost reduction of electronic equipment in the field of office automation and the like has been promoted, and there is a demand for cost reduction of a motor, which can be said to be the heart of its drive system. Bearings occupy a large amount of weight in the material cost of this motor, but highly reliable miniature ball bearings are extremely expensive, while oil-impregnated sliding bearings, which are relatively low cost, have high reliability. In terms of performance, there is a problem in that it is slightly inferior to the miniature ball bearings, and in order to cope with the cost reduction of motors, there has been a demand for higher reliability of oil-impregnated slide bearings.

FIG. 3 is a half sectional view showing the structure of a conventional bearing device for an axial flow fan motor. In FIG. 3, 1 is a shaft, and 2 and 3 are oil-impregnated slide bearings that rotatably support the shaft 1. Reference numeral 4 is a washer that receives a load in the thrust direction, 5 is a retaining ring for stably contacting the washer 4 with the oil-impregnated sliding bearing 3, 6 is a stator boss for housing and fixing the oil-impregnated sliding bearings 2 and 3, and 7 is a stator boss. Shaft 1
A rotor frame 8 connected to the rotor frame 8 is a stator fixed to an outer peripheral portion of a stator boss 6. A field magnet 9 and a stator adhesively fixed to the rotor frame 7 and a driving coil 10 wound around the stator. The motor is configured to rotate due to the magnetic repulsion action of. Reference numerals 11 and 12 denote an oil drainer for preventing oil from flowing out from the rotor frame side and an oil leakage prevention cap for preventing oil leakage from the side opposite to the rotor frame side, and 13 controls commutation of the drive coil 10. The drive circuit is shown.

The operation of the conventional bearing device configured as described above will be described below. First, the stator 8
When the rotor frame 7 and the shaft 1 rotate due to the magnetic repulsion between the rotor and the field magnet 9, the inner diameter surfaces of the oil-impregnated plain bearings 2 and 3 and the outer diameter surface of the shaft 1 slide, and the friction heat generated The oil-impregnated sliding bearings 2 and 3 due to the occurrence of expansion and decrease in viscosity of the lubricating oil, and the oil-impregnated sliding bearings 2 and 3
3. Lubricating oil flows out by both of the pumping action of 3 itself. The oil that has sprung out is pushed in a narrow gap formed by the shaft 1 and the inner diameter surfaces of the oil-containing sliding oil receivers 2 and 3 in a wedge shape to generate pressure in the oil film, and this pressure moves the shaft 1 upward. It acts as a floating force, keeps the frictional resistance between them to a minimum, and acts to maintain a lubrication state where metal contact does not occur for a long period of time.

[0005]

However, in the above-mentioned conventional structure, the radial load which is carried by both the oil-impregnated plain bearings 2 and 3 is naturally the rotor frame 7,
Due to the relationship between the moment of the field magnet 9 with respect to the center of gravity position and the moment of the unbalanced load applied to the tip of the shaft 1, the oil-impregnated slide bearing 2 on the rotor frame 7 side is the oil-impregnated slide bearing 3 on the opposite rotor frame side.
As compared with the above, the load becomes higher, and the oil consumption state of both bearings is deviated, which causes a deviation in the life of both bearings.

Due to this deviation in bearing life, the oil-impregnated plain bearing 3 on the side opposite to the rotor frame is not damaged.
Despite the fact that there is sufficient oil remaining, the oil-impregnated plain bearing 2 on the rotor frame 7 side is damaged by the oil consumption first and reaches the end of its life. Therefore, the life of the entire bearing is dragged by it. Tended to be short.

In order to improve this, conventionally, there has been adopted a method of providing a difference in shape between two oil-impregnated slide bearings, such as enlarging the oil-impregnated slide bearing 2 on the high load side. However, with this method, it is necessary to raise two molds for bearings of different shapes, the material cost increases due to the enlargement of the oil-impregnated plain bearing 2, and the dimensional control becomes two types, which complicates the work. In addition, the oil-impregnated plain bearing itself and the motor equipped with it have increased the cost.

The present invention solves such conventional problems,
The purpose is to correct bearing load deviations and extend the service life with a simple configuration.

[0009]

SUMMARY OF THE INVENTION In a motor bearing device of the present invention, at least two or more independent oil-impregnated slide bearings are brought into contact with each other, and the porosity of the oil-impregnated slide bearings is intentionally provided with an appropriate deviation beforehand. It is provided.

[0010]

According to the present invention, the rotor frame and the shaft rotate due to the magnetic repulsion between the stator and the field magnet, and the oil film pressure is generated between the shaft and the oil-impregnated slide bearing. And the oil-impregnated plain bearing on the low load side, when the difference in the oil consumption state due to the magnitude of the load occurs, the porosity of the oil-impregnated plain bearing on the high load side, which has a high oil consumption rate, is reduced in advance. By setting the porosity smaller than that on the load side, a capillary phenomenon occurs on both contact surfaces, and oil on the low load side, which has a low oil consumption rate, is absorbed in the oil-impregnated plain bearing holes on the high load side. This can be used for lubrication of the bearing on the high load side.

[0011]

1 is a half sectional view showing the structure of a bearing device for an axial fan motor according to an embodiment of the present invention.
The same reference numerals are used to indicate the same components among the conventional components. This bearing device for an axial fan motor is different from the conventional example in that an oil-impregnated slide bearing 21 on the rotor frame 7 side and an oil-impregnated slide bearing 31 on the opposite rotor frame 31 are used.
Both are placed in contact with each other, and as shown in FIG.
As shown in the enlarged view of the oil-impregnated plain bearings 21 and 31 in FIG. 1 by a microscope in (b), the former has a relatively low porosity as compared with the latter. .

In the bearing device of the axial fan motor constructed as described above, the rotor frame 7 and the shaft 1 are rotated by the magnetic repulsion action of the stator 8 and the field magnet 9, and the oil film pressure due to the oil outflow. Occurs between the shaft 1 and the oil-impregnated plain bearings 21, 31. Then, between the oil-impregnated slide bearing 21 on the rotor frame 7 side and the oil-impregnated slide bearing 31 on the counter rotor frame side, a deviation of the oil consumption state due to the magnitude of the bearing load occurs. At this time, the porosity of the oil-impregnated sliding bearing 21 on the rotor frame 7 side where the oil consumption rate is large in advance is set to the oil-impregnated sliding bearing 31 on the counter rotor frame side.
Is smaller than the porosity of the oil-bearing surface, the capillary phenomenon occurs on both contact surfaces, and the oil of the oil-impregnated slide bearing 31 on the side opposite to the rotor frame, which has a low oil consumption rate, is oil-impregnated on the high-load side of the rotor frame 7 It can be absorbed in the opening of the slide bearing 21 and used for lubrication of the bearing on the high load side.

The difference in porosity shown in FIGS. 2 (a) and 2 (b) described above can be realized by using materials having different particle sizes.
Generally Cu-based bearing materials with different particle sizes, or Cu-F
This can be made possible by appropriately arranging e-type bearing materials or mutually different bearing materials.

Since the two materials have the characteristics of high conformability and high wear resistance,
Arranging the same bearing device by making the best use of the features of both can greatly contribute to the high reliability of the bearing device in this sense as well.

[0015]

As described above, the motor bearing device of the present invention is extremely simple in that two oil-impregnated slide bearings are brought into contact with each other and that the oil-impregnated slide bearing is intentionally provided with an appropriate deviation. The structure corrects the deviation of the oil consumption rate due to the difference in bearing load, which has hindered the high reliability of the conventional oil-impregnated sliding bearings, and effectively uses the oil contained in the oil-impregnated sliding bearings to extend the life of the bearings. It is possible to provide an inexpensive motor bearing device.

Further, according to the present invention, as in the method of providing a difference in the shape of each oil-impregnated sliding oil receiver that has been conventionally used, two types of oil-impregnated sliding bearings are controlled in terms of mold and size, and materials. It is possible to effectively use the same die without considering the cost increase and the like, which also contributes to the realization of a low cost and highly reliable motor bearing device.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a structure of a bearing device for an axial fan motor according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing the porosity of each oil-impregnated sliding bearing on the rotor frame side and the non-rotor frame side of FIG.

FIG. 3 is a half sectional view showing a structure of a conventional bearing device for an axial fan motor.

[Explanation of symbols]

1 ... Shaft, 4 ... Washer, 5 ... Stop ring,
6 ... Stator boss, 7 ... Rotor frame, 8 ... Stator, 9 ... Field magnet, 10 ... Driving coil,
11… Oil drainer, 12… Oil leakage prevention cap, 13… Drive circuit, 21… Rotor frame side oil-impregnated slide bearing, 31… Anti-rotor frame side oil-impregnated slide bearing.

Claims (2)

[Claims] 1. A rotor frame having a field magnet on an inner circumference thereof, a shaft connected to the rotor frame, an oil-impregnated bearing for rotatably supporting the shaft, the oil-impregnated bearing being housed and fixed therein, and a stator being provided on an outer periphery thereof. In a configuration having a stator boss fixed to a portion, the oil-impregnated bearing is composed of at least two oil-impregnated slide bearings having different porosities that are in contact with each other. 2. The two or more oil-impregnated plain bearings having different porosities that are in contact with each other are made of Cu-based bearing materials having different grain sizes, Cu-Fe-based bearing materials, or bearing materials different from each other. The bearing device for the motor according to claim 1.