JPS6138374Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The purpose of the present invention is to change the natural frequency generated by the coupling between the load and the rotating electrical machine when a load is directly connected to the rotating electrical machine, such as a blower motor with a fan directly connected to the shaft end. As noise pollution has become more of a focus in recent years, there has been a demand for lower noise from motors, etc., but the most difficult problem is magnetic noise, which occurs when connected to a load. The noise caused by the resonance between the new natural frequency and the motor's electromagnetic excitation force is difficult to predict because the user's load has a variety of natural frequencies, and in many cases it only becomes a problem after use. Therefore, in this invention, the bearing of the motor is made to be able to slide in the axial direction, and when noise is generated due to the resonance between the natural frequency and the electromagnetic excitation force due to the connection with the load, the bearing is moved to move the bearing between the bearings. Resonance with the electromagnetic excitation force of the motor is avoided by changing the distance and changing the natural frequency generated by the coupling between the motor and the load. An embodiment of the present invention will be described below in comparison with a conventional example. Figure 1 shows a conventional state in which a motor 1 and a fan 2 are directly connected.The natural frequency of the shaft system including the fan matches the electromagnetic excitation force of the motor, and when resonance occurs, the fan receives that frequency. It generates vibration and noise. FIG. 2 shows a structural diagram of a conventional motor, in which a shaft 5 with a rotor 3 has bearings 4 and 9.
It is rotatably supported by. FIG. 3 shows a bearing section according to an embodiment of the present invention. In the bearing section on the anti-load side, a push-in tab 6 with a thread cut on the inner diameter of the bracket 8 and a thread cut on the outer diameter is tightened via a spacer 7. There is. According to this structure, as shown in FIG. 4, by removing the spacer 7 and tightening the pusher 6, the anti-load side bearing 4 moves in the axial direction, and the distance from the load side bearing 9 is shortened by the width α of the spacer. Therefore, the general formula for the spring constant of the shaft supported by the bearing is m = 48EI/l
The spring constant of the shaft changes as shown at ³ . Also, the general formula for the natural frequency is

[Formula] (f: natural frequency, m: spring constant, W = weight). That is, by changing the distance between the bearings, the spring constant of the shaft changes, which changes the natural frequency. As described above, according to the present invention, there is no need to disassemble the rotating electric machine or specially process the parts.
By simply screwing a push-button into the bracket, the natural frequency generated by the fan and motor can be changed, and noise caused by resonance with electromagnetic excitation force can be eliminated. be.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a direct connection between a conventional motor and a fan, Fig. 2 is a front cross-sectional view showing an example of a conventional motor, and Figs. 3 and 4 are an example of a motor of this invention. FIG. 3 is an enlarged front sectional view showing a portion of the bearing on the opposite load side. In the figures, the same reference numerals indicate the same or corresponding parts, 1 is the motor, 2 is the fan, 3 is the rotor, 4 and 9 are the bearings, 5 is the rotation shaft, 6 is the pushbutton, 7 is the spacer, 8 indicates a bracket.

Claims (1)

[Scope of utility model registration request] A bracket that has a bearing that rotatably holds rotating shafts protruding from both sides of a rotor, a bearing portion into which the bearing is fitted, and a threaded portion provided on the inner diameter of the bearing portion; In a rotating electric machine that has a pusher tab that is provided with a threaded portion that is screwed into the threaded portion of the bracket, the pusher tab is screwed into the threaded portion of the bracket, and the bearing is pressed by the pusher tab to cause the rotation. A rotating electric machine characterized in that the distance between the bearings on both sides that sandwich the child can be adjusted.