JP4010426B2 - Fan bearing structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a fan, in particular relates to an improvement of the bearing structure of a fan bearing housing opening face is sealed.
[0002]
[Prior art]
Examples of the prior art are shown in FIGS. FIG. 4 is a cross-sectional view of an example of a conventional axial fan, and FIG. 5 is a partially enlarged cross-sectional view showing the bearing box 1-1 of the example of FIG. 4 and the oil-impregnated bearing 4 attached to the bearing box 1-1. FIG. 6 and FIG. 6 are front views of FIG. 5, a casing 1 in which a bearing box 1-1 is integrally formed, a stator 2-1 held by the casing 1, and a gap between the stator 2-1 and the stator 2-1. And a motor 2 having a rotor 2-2 that is rotatably supported by an oil-impregnated bearing 4 mounted on the bearing box 1-1, and held integrally with the rotor 2-2 of the motor 2. The structure of the axial flow fan is shown in which the opening surface of the bearing box 1-1 is sealed by a plate member 5. In such a configuration, the heat dissipation of the temperature rise mainly due to energization for driving the motor 2 serves as a heat conduction path to hold the stator core and the stator core and the cylindrical portion of the casing 1 forming the bearing box 1-1. Heat transfer from the inside of the bearing housing to the outside together with the structure in which the opening end of the bearing housing 1-1 is sealed by the plate member 5 to block outside air for the purpose of normally preventing dust. It was inevitable that only the temperature around the bearing was likely to increase in temperature.
[0003]
In response to the need for lower prices, the oil-impregnated bearing 4 is often used as the bearing, and the bearing box 1 is increased due to an increase in pressure caused by a rise in temperature inside the sealed bearing box 1-1. Actually, the degree of leakage of the lubricating oil impregnated in the oil-impregnated bearing 4 from -1 to the outside has increased. The relationship between the temperature rise inside the bearing and the leakage of the lubricating oil is such that the inner peripheral surface of the bearing housing 1-1 and the outer peripheral surface of the oil-impregnated bearing 4 are fitted in a pressure contact state over the entire surface, Since the surface naturally slides over the entire rotor shaft 2-3, convection between the front and rear end surfaces of the oil-impregnated bearing 4 can hardly be expected. In particular, the outside air is the rotor shaft 2- The location of the heated lubricating oil on the side of the rotor yoke 2-2 adjacent to and facing the small hole 1-2 of the casing penetrating the rotor 3 is the rotor shaft 2-3 as the ventilation gap and the rotation This is based on the existence of a gap with the small hole 1-2 through which the child shaft 2-3 is inserted, which must be external.
[0004]
[Problems to be solved by the invention]
In the conventional configuration as described above, due to heat dissipation from the motor and the oil-impregnated bearing by driving, the pressure on the opening end side of the bearing box 1-1 that is blocked from the outside air by the plate member 5 is increased, Air expanded by heat flows from the clearance between the oil-impregnated bearing and the rotor shaft due to the pressure difference to the impeller side. At this time, the lubricant flowed out together with the flow of air, and the life of the fan was reduced.
[0005]
[Means for Solving the Problems]
The fan bearing structure according to the present invention includes a groove that extends in an axial direction longer than the entire length of the oil-impregnated bearing on the inner peripheral surface of the bearing box , opens to both ends of the oil-impregnated bearing, and is connected to the groove and has a rotor shaft. And / or a radial groove at the back end that reaches the small hole of the casing through which the rotor shaft is inserted, and / or a shallower diameter than the small hole through which the rotor shaft is inserted at the back end of the bearing box of the casing. A step is formed, and preferably four radial grooves at the back end are formed so as to reach the inner peripheral surface of the step.
[0006]
In the configuration as described above, it is possible to prevent the lubricating oil contained in the built-in oil-impregnated bearing from leaking to the outside due to the temperature rise of the fan itself due to driving, so that consumption of the lubricating oil can be suppressed and the life of the fan can be reduced. Can be extended.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an example of an axial fan according to the present invention, and FIG. 2 is a partially enlarged sectional view showing a bearing box 1-1 and an oil-impregnated bearing 4 mounted on the bearing box 1-1 in the example of FIG. FIG. 3 and FIG. 3 are front views of FIG.
[0008]
The overall structure of the fan is the same as the conventional structure shown in FIG. 4 described above, and has a feature in the inner peripheral surface on which the oil-impregnated bearing 4 of the bearing box 1-1 integrated with the casing 1 is fitted. An axial groove 1-11, which is longer than the length of the oil-impregnated bearing 4 to be fitted, is formed on the inner peripheral surface of the bearing box 1-1. In the portion, a radial groove 1-12 is formed on the back end surface communicating with the axial groove 1-11.
[0009]
The groove 1-11 extending in the axial direction and the radial groove 1-12 communicating therewith are energized to the motor 2 during the operation of the fan, the inner peripheral surface of the oil-impregnated bearing 4 and the rotor shaft 2- Even if the lubricating oil contained in the oil-impregnated bearing 4 oozes out on either end face of the bearing due to sliding with the bearing 3, it functions as a ventilation channel between the bearing surfaces. Can be prevented.
[0010]
Further, in the prior art, the presence of the shallow stepped portion 1-3 formed as a relief for facilitating the processing of the fitting inner peripheral surface of the oil-impregnated bearing 4 of the bearing box 1-1 of the casing 1 is the result of the shallow stepping. The small space of the portion 1-3 corresponds to the space on the opening side of the bearing housing 1-1 with respect to the circulation path between the groove 1-11 extending in the axial direction and the radial groove 1-12 communicating with the groove 1-11. Thus, it functions effectively as a place where the lubricating oil that has temporarily oozed out at the back end also prevents leakage to the outside.
[0011]
【The invention's effect】
The fan bearing structure as described above can prevent the lubricating oil contained in the built-in oil-impregnated bearing from leaking to the outside due to the temperature rise of the fan itself by driving, thereby extending the life of the fan.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an example of an axial fan according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing a bearing portion in the example of FIG.
FIG. 3 is a front view of the example of FIG. 2;
FIG. 4 is a cross-sectional view of an example of an axial fan according to the prior art.
5 is an enlarged cross-sectional view showing a bearing portion in the example of FIG.
6 is a front view of the example of FIG.
[Explanation of symbols]
1 Casing 1-1 Bearing box 1-11 Groove extending in the axial direction longer than the oil-impregnated bearing 1-12 Radial groove communicating with the axial groove 1-2 The rotor shaft formed at the back end of the bearing box Small hole 1-3 to be inserted Shallow level difference 2 formed at the inner end of the bearing box Motor 2-1 Stator 2-2 Rotor 2-21 Rotor yoke 2-3 Rotor shaft 3 Impeller 4 Oil-impregnated bearing 5 Plate member

Claims (3)

A casing integrally formed with a bearing box; a stator held by the casing; and a rotor rotatably supported by an oil-impregnated bearing mounted on the bearing box so as to face the stator via a gap. And a fan bearing structure in which an opening surface of the bearing box is sealed, and the oil-impregnated bearing on the inner peripheral surface of the bearing box A groove extending in the axial direction longer than the total length of the oil-impregnated bearing and opening at both end sides of the oil-impregnated bearing, and a radial groove at the back end leading to the small hole of the casing communicating with the groove and penetrating the rotor shaft And a fan bearing structure. A shallow step having a diameter larger than a small hole penetrating the rotor shaft is formed at the back end portion of the bearing box of the casing, and a radial groove at the back end portion reaches an inner peripheral surface of the step. The fan bearing structure according to claim 1, wherein the fan bearing structure is formed as described above. 3. The fan bearing structure according to claim 1, wherein the axially extending groove and the four radial grooves communicating with the axially extending groove are substantially equally arranged in the circumferential direction.

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