JPH0779539A - Vibration isolator for fan motor - Google Patents

Abstract

PURPOSE:To enhance heat resistance, reliability and vibration isolating performance of a fan motor without increasing the cost or the number of manufacturing steps by suppressing vibration of the rotor shaft. CONSTITUTION:A fan 5 is constructed of an inner peripheral part 3 to be secured with a rotor shaft and an outer peripheral part 4 to be arranged with the vane 6 of the fan. An air gap 23 is provided between the inner peripheral part 3 and the outer peripheral part 4 which are coupled by means of a plurality of fasteners 2 thus obtaining a fan excellent in the vibration isolating performance. This structure eliminates the need of rubber vibration isolator thus enhancing heat resistance, reliability and vibration isolation performance without causing any increase in the cost or the number of manufacturing steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolation device for fan motors used in room air conditioners and water heaters.

[0002]

2. Description of the Related Art In recent years, the rotation speed of a fan motor has been frequently controlled from the viewpoint of air blowing or combustion efficiency, and the fluctuation of vibration of the fan motor becomes more and more large, which causes unpleasant vibration and noise. Are tending to increase.

A conventional fan motor of this type will be described with reference to FIG. As shown in the figure, the fan motor is composed of a stator 11 and a rotor 14, and the rotor 14 is rotatably assembled to the stator 11 via a bearing 10.

The fan 5 is attached to the rotor shaft 9 which constitutes this rotor through fixing washer plates 7a and 7b, and in order to make it difficult to transmit the rotational fluctuation of the rotor shaft 9 to the fan 5, a vibration isolating rubber washer is provided. 22 are arranged in a sandwich structure and are integrally fixed by a nut 8.

This prevents vibrations generated by the rotor when the rotor is rotated from being transmitted to the fan and causing unpleasant vibrations and noises due to the resonance phenomenon.

[0006]

In order to increase the above-mentioned vibration-proof effect, it is desirable to increase the thickness of the vibration-proof rubber washer 22 and further reduce the tightening amount of the fixing nut 8.

However, in this way, the vibration from the rotor is less likely to be transmitted to the fan, but when the fan rotates, the fan shakes, the amount of blown air is unstable, and the fan interferes with the fan case. This will cause trouble.

Further, when a rubber washer is used for vibration isolation, the number of assembling steps is increased, which is disadvantageous in terms of cost, and there is a problem in heat resistance of the rubber washer.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a fan motor having excellent heat resistance, reliability, and vibration isolation without increasing costs or increasing manufacturing steps. And

[0010]

In order to achieve this object, a vibration isolator for a fan motor according to the present invention comprises an inner peripheral portion for fixing the fan to a rotor shaft, and an outer peripheral portion on which fan blades are arranged. The inner peripheral portion and the outer peripheral portion are connected to each other by a plurality of fastening portions.

[0011]

According to the above construction, it is difficult to transmit the vibration in the rotating direction generated in the rotor shaft to the fan. The operation will be described below.

FIG. 4 shows an example of the torsional vibration system, but the natural frequency of the torsional system can be generally obtained by the equation (1). Natural frequency = (K (J ₁ + J ₂ ) / J ₁ J ₂ ) ^0.5 / 2π (Hz) ………… (1) J ₁ : Rotor inertia J ₂ : Fan inertia K: In this case, fan circumference Torsional spring constant in the direction of rotation of the fan generated by connecting the inner and inner parts with multiple fastening parts. From the vibration isolation theory, the natural frequency of equation (1) can be set to (1/2) ^0.5 or less of the cutoff frequency. The better the difference, the greater the anti-vibration effect. In this case, except for the fact that the fastening part that fastens the inner and outer circumferences withstands the force that transmits the required torque, and that the rotational fluctuation of the fan is kept within an allowable range depending on the application, it is as much as possible from the standpoint of anti-vibration performance. The rigidity can be reduced. In addition, the gap between the fan and the fan case, which must be ensured in the fan motor, is uniformly maintained by the fastening portion having a shape having a large rigidity in the radial direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to. The same numbers are used for the same components as those described in the conventional example.

As shown in the drawing, the fan 5 has an inner peripheral portion 3 integrally fixed to the rotor shaft 9 and an outer peripheral portion 4 on which the blades 6 of the fan 5 are arranged, and the inner peripheral portion 3 and the outer peripheral portion 4 are provided. Are connected with the fastening material 2 to form the void 23.

The operation of the fan of the fan motor configured as described above will be described with reference to FIG. Figure 2
[FIG. 3] is an enlarged view of a portion of the fastening material 2. The rigidity of the fastening member 2 can be selected by the width W and the length L.

By adjusting the rigidity of the fastening member 2 in accordance with the conditions under which the fan motor is actually used, vibrations such as fluctuations in the cogging torque generated in the rotor are indicated by a solid line from the state 2b in which the connecting member 27 is indicated by a dotted line. FIG. 2 shows a state in which the vibration of the rotor shaft is difficult to be transmitted to the fan by deforming like the state 2a shown.

In this case, when the fan of this embodiment and the conventional general fan are assembled and operated in a DC brushless fan motor as shown in FIG.
It has been confirmed that the sound generated from the C brushless fan motor is reduced by about 10 dB in the fan motor equipped with the fan of this embodiment. Further, in the fan of the present embodiment, since the vibration isolating structure using the fastening material is integrally formed with the fan, the cost and manufacturing process are not increased as compared with the case where the conventional vibration isolating rubber is used. It can be carried out.

[0018]

As is apparent from the above description of the embodiments, the inner peripheral portion for fixing the fan to the rotor shaft and the outer peripheral portion where the fan blades are arranged are connected by a plurality of fastening members, and their shapes are changed. By proper selection, vibrations can be effectively absorbed, and unstable factors such as thermal deformation and aging due to the use of rubber can be eliminated. Further, the fan according to the present invention can provide a fan of a fan motor excellent in durability, reliability, and vibration isolation without increasing costs and increasing manufacturing processes.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional perspective view of a vibration isolation device for a fan motor according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a fan fastening material portion of a vibration isolation device for a fan motor according to an embodiment of the present invention.

FIG. 3 is an assembly diagram of a fan motor according to an embodiment of the present invention.

FIG. 4 is a perspective view showing an example of a torsional vibration system.

FIG. 5 is a sectional view of a conventional fan motor.

[Explanation of symbols]

 1 rotor shaft mounting hole 2, 2a, 2b fastening material 3 inner peripheral part 4 outer peripheral part 6 blades 7a, 7b fixing washer plate 8 nut 9 rotor shaft 10 bearing 11 stator 14 rotor 22 anti-vibration rubber washer 23 void

Claims (2)

[Claims] 1. A fan blade portion is provided on an outer peripheral portion, a rotor shaft mounting hole for fixing a rotor shaft is provided on an inner peripheral portion, and the outer peripheral portion and the inner peripheral portion are connected by a plurality of fastening members. Anti-vibration device for fan motors. 2. A fan motor comprising an outer peripheral portion for arranging blades on a fan, an inner peripheral portion fixed to a rotor shaft, and a plurality of fasteners for connecting the outer peripheral portion and the inner peripheral portion, which are integrally formed. Anti-vibration device.