JPS6116300A - Axial flow fan - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an axial fan mounting system that incorporates motor protection and a single stage of motor cooling. Although the invention is not limited to evaporative coolers, it is particularly suitable for use with coolers where the air stream may include entrained water droplets.

There are many applications, including applications in evaporative coolers where it is desirable to optimally protect fan motor insulation from breakdown due to moisture.

However, completely enclosing the motor requires the use of a larger frame than would be required for a bare motor, and it is desirable that the motor be open to cooling air. The limiting factor is the temperature rise of the motor windings, which must not be allowed to exceed the limits determined by the properties of the insulation material used.

A principal object of the invention is to provide an improved mounting arrangement in which the motor is protected against excessive ingress of moisture that would otherwise be entrained in the air, yet is cooled by the air flow.

The present invention utilizes the phenomenon that when all moisture except very small particles is entrained in an airflow, it remains in the direction of travel even if the direction of the airflow itself changes. , and the present invention is summarized as follows. That is, the motor carries the knob of the fan, the knob being carried by the hub from inside the hub through the leading edge at the high speed, low pressure area and through the leading edge at the high speed and low pressure area. an opening extending outwardly upstream of the fan blade, the motor being mounted to the motor mounting frame and extending at least a portion of the hub such that there is an air entry gap between the downstream end of the hub and the motor. It is located inside.

With this configuration, a backflow of air occurs from the high pressure area at the air entry gap through the motor to the high speed low pressure area above the motor.

More particularly, the invention comprises an axial fan mounting arrangement in which a motor is mounted to a motor mounting frame, a motor shaft carries a fan hub thereon, and the fan blades radially diverge from the hub. , the hub of the fan has a hollow dish-like member having a forwardly converging leading edge and an air flow opening extending from the inside through the leading edge at a high speed, low pressure region to the outside of the hollow hub upstream of the fan blades; is located at least in part within the intermediate portion of the fan hub, and there is an air entry gap downstream of the hub and the motor, and there is sufficient space between the hub and the motor. The air flow path from the air inlet gap to the air flow opening is completely formed.

Hereinafter, one embodiment of the present invention illustrated in the accompanying drawings will be described with reference to one drawing.

In this embodiment, a relatively small fan motor is disposed in the evaporative cooler 1o in order to allow air to pass through and cool not only the outer surface but also its windings. The motor has a projecting shaft 12 with a non-circular front end 13, which shaft is held in a central boss 14 of a hollow hub 15.

The hollow hub 15 is a dish hub with a domed or curved end 16 at the upstream end, and a plurality of air flow openings 17 extend from the interior of the dish, surrounding the center of the dome and Extending to the outer surface of the dome at a distance from the center of the dome near the transition point from the dome to the cylindrical part, its opening extends to the high-velocity and therefore low-pressure region z1 of the outer surface of the hollow dome.
open to

The walls of the dome extend downstream and support fan blades 20 that extend radially outwardly at a plurality of spacings. Here, the blades 20 are generally in accordance with known technology.

The motor and fan combination is part of an evaporative cooler, which draws air through an absorbent pad through which water flows, so that the air is cooled as it passes through the motor and fan combination. Not only can small water droplets be entrained.

The motor 11 is attached to a motor mount 21 that is part of the frame of the cooler 10 and is spaced downstream from the downstream end of the knob 15. Therefore, there is an air entry gap 22 (a third
) exists, through which the air flows through the fan blades 20
High pressure area Z downstream of.

from there, across the motor 11, past its windings, and out all the way through the airflow openings 17 at the upstream end of the knob 15 and near the outer periphery of the dome face.

Considering the upper air embodiment, it can be seen that the present invention has many advantages over the prior art.

First, the motor is well air-cooled by the air pre-cooled by the entrained evaporated water, but most of the water droplets entrained in the airflow that have not yet been evaporated remain in the axial flow and the fan is not carried to the motor by a small air flow from the high pressure region Z2 downstream of the vanes into the hollow of the hub. Second, the motor is effectively cooled;
The frame can be relatively compact for a given force. Third, the overall space occupied by the motor and fan combination is much less than that of the prior art iC, so that, for example, a fixture containing the fan would require the motor to be in parallel with the fan. That is, it is much thinner across anteflexion and takes up less space than conventional devices. Many variations can be introduced to the invention, and include, for example, the gradual shape of the dome and cylindrical surface of the dome to provide less pressure at the opening where the air flows back from the motor into the main air stream. It will of course be understood that it is also possible to interrupt at the surface. It is also possible to use an annular scoop device to extract air from the downstream side back into the hollow part of the knob. However, the efficiency of the device shown in this preferred embodiment is so high that these additional features are usually not necessary. Although the machine described above does not require metal fasteners to fasten the fan to the motor shaft, they can be used if desired. However, it will be appreciated that these and similar variations are included within the present invention.

[Brief explanation of drawings]

Figure 1 shows the motor mounting frame (part of the evaporative cooler),
FIG. 2 is a front view of the fan, and FIG. 3 is a partial side view showing the fan, motor, and motor mounting frame. 10...Cooler, 11...Motor, 1
2...Axle, 13...Non-circular front end, 14
...Central boss, 15 ...Hollow hub, 1
7... Air flow opening, 20... Vane,
21... Fixture, 22... Air entry gap, zl... High speed low pressure area, Z2... High pressure area.

Claims (4)

[Claims] (1) A mounting device for an axial fan in which a motor is mounted on a motor mounting frame, a motor shaft carries a fan hub thereon, and fan blades extend radially from the hub, the fan hub being , having a hollow dish-shaped member having a forwardly converging leading edge and an airflow opening extending from the inside through the leading edge at a high speed, low pressure region to the outside of the hollow hub upstream of the fan blades; , at least partially contained within the hollow portion of the hub of the fan, there is an air inlet gap between the downstream end of the hub and the motor, and between the hub and the motor, from the air inlet gap to the air flow opening; An axial fan mounting device characterized by having sufficient space to create an air flow path. (2) The motor mounting frame is part of the evaporative cooler and is downstream of the moist evaporative pad, so that the air passing through the motor and fan can be cooled together and entrain water droplets from the pad. The axial fan mounting device according to claim 1, characterized in that: (3) The leading edge of the hub is dome-shaped, and the hub has a trailing edge cylindrical portion, and the high-speed, low-pressure area is near the transition between the dome-shaped leading edge and the trailing edge cylindrical portion of the hub. An axial fan mounting device according to claim 1 or 2, characterized in that: (4) The axial flow fan according to claim 1 or 2, wherein the motor has a motor shaft that projects forward and backward, and the hub is supported on the forward projecting end of the shaft. Mounting device.