Centrifugal fan

The present invention relates to a means for suppressing a temperature rise of a bearing, which is related to the life of a centrifugal fan.

<patcit num="1"><text>Japanese Patent Application Laid-Open No. 07-046811</text></patcit>

In the centrifugal fan and the like according to the present invention, the needs for performance improvement and long life are not alleviated even as the miniaturization progresses, and the brushless DC motor, which is often used as a power source for these, also has a drive circuit built-in. As seen in the above-mentioned prior application publication, consideration for heat dissipation of the electronic components constituting the drive circuit is indispensable, and the temperature rise of the bearing, which is directly related to the life of the bearing, is indispensable. It is well known that suppression is also an important issue.

FIG. 3 shows an example of the above-mentioned conventional configuration, in which the rotor hub 2-1 is usually formed by resin molding integrally with the impeller. Further, the bearing box held in the central portion of the casing 1 and fitted with the circuit board forming the stator and the drive circuit on the outer peripheral surface thereof is usually formed of a metal member.

In addition, FIG. 4 shows another well-known example, showing a rotor hub integrated with a rotor yoke made of a metal member, and since the rotor hub made of metal is exposed to ventilation, it is internal. Although it promotes heat dissipation, the shape of the rotor hub head is damaged and smooth ventilation is not performed, so the cooling effect is not sufficient.

<p> The conventional configuration as described above is effective as a high temperature avoidance measure on the heat dissipation surface of electronic components that are directly related to performance and operation, but the stator held on the outer peripheral surface is attached to the winding for driving. The heat generated by energization is directly fitted to the inner peripheral surface, which leads to an increase in the temperature of the bearing, which is related to the life, and improvement is left as an issue in terms of the influence on the life.</p>

<p>The centrifugal fan according to the present invention has a suction port that opens in the axial direction and a discharge port that opens in the circumferential direction, and has a shape in which the annular inner peripheral surface gradually expands from the upstream side to the downstream side. The rotor includes a shape casing, a rotor built in the cochlear-shaped casing, and a rotor hub that is fixedly held on a rotation shaft and rotatably holds the rotor of the rotor and the multi-blade impeller. The hub has an arcuate head in cross section, is formed of a good heat conductor such as metal, and preferably, the bearing box into which the bearing member that supports the rotation axis is fitted is integrally molded with the cochlear-shaped casing. It is formed.</p>

<p> The centrifugal fan according to the present invention increases heat dissipation by aeration accompanying the operation as a fan, reduces the temperature rise of the bearing, and realizes a long life. If the bearing box is made of a heat-resistant conductor such as resin, heat propagation from the stator side can be suppressed, and a longer life can be realized. Further, by forming the bearing box with a heat-resistant electric member such as resin, heat propagation from the stator side can be suppressed, and a longer life can be realized.</p>

Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a semi-cross-sectional view showing the first embodiment, in which the head portion of the rotor hub 2-1 has a large arc shape and is formed of a metal member or the like having excellent thermal conductivity, and has an arc shape surface. The heat generated inside the rotor hub 2-1 and the heat of the bearing 5 are dissipated by the ventilation flowing through the rotor hub 2-1.

The bearing box (1-1) is also made of resin as a heat-resistant conductive member integrally with the casing 1 formed by resin molding, so that the stator 3 of the rotating machine fixed to the outer peripheral surface and the drive circuit are used. The heat generation is made difficult to propagate to the bearing 5 fitted on the inner peripheral surface.

FIG. 2 is a semi-cross-sectional view illustrating the second embodiment, in which the bearing box 1-1 is formed of a metallic good thermal conductor. Similar to the first embodiment described above, the head portion of the rotor hub 2-1 has a large arc shape, is formed of a metal member or the like having excellent thermal conductivity, and the rotor hub is ventilated through the arcuate surface. The configuration is such that the heat generated inside the 2-1 and the heat generated from the stator 3 are dissipated through the bearing box 1-1 and the bearing 5.

This configuration reduces the thermal effect on the bearing 5 compared to FIG. 1, but is effective for extending the life of the entire product.

The centrifugal fan according to the present invention can be widely used as a fan for achieving a long life, which is considered to be important among many needs.

<figref num="1">It is a half sectional view explaining the 1st example which becomes a present invention.</figref><figref num="2">It is a half sectional view explaining the 2nd example which becomes a present invention.</figref><figref num="3">It is a half sectional view explaining the example of the prior art.</figref><figref num="4">It is a half sectional view explaining another example of the prior art.</figref>

Code description

1 Casing 1-1 Bearing box (1-1) Bearing box integrated with the casing 2 Multi-blade impeller 2-1 Rotor hub 2-1'Practical metal rotor hub 3 Stator 3-1 Winding 4 Rotor shaft 5 Bearing 6 Inflow ventilation