JPS61125567A - Operatiion method of motor 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] [Field of Application of the Invention] The present invention relates to an operating method when a plurality of electric blowers of the same type are built into the same device and are operated simultaneously, and particularly relates to an operating method for a computer, a copying machine, and a printer. The present invention relates to a method of operating an electric blower that is built-in for cooling inside an office and is suitable for a device operated in an office or the like where people are present.

[Background of the invention]

Conventionally, the multi-dimensional phenomenon has been discussed in Introduction to Mechanical Vibration, by Yo Kobori.
Translated by Maruzen Co., Ltd., published in March 1975, pages 8-9, and Sound and Vibration, written by Hisashi Igarashi, published by Kyoritsu Publishing, published in January 1960, page 357, etc., describe the theory, and the theory is widely used. is known for. Furthermore, regarding the noise of axial flow fans, each manufacturer takes measures to reduce the noise of the fan itself, and the peak sound pressure due to the rotation speed and number of blades is almost non-existent. becomes larger. Therefore, if a plurality of electric blowers of the same type are operated simultaneously in one device, a whirring phenomenon will occur.

A countermeasure against the eel phenomenon is to shift the frequency of a general VC, often using a different type of electric blower. However, no consideration was given to the fact that mounting parts, the shape of the intake port, the exhaust port, and the different parts would increase the cost.

[Purpose of the invention]

The purpose of the present invention is to detect a slight wind noise (siren sound) due to the rotational speed and number of blades of the electric blower when multiple electric cooling blowers of the same type are operated simultaneously in one device. When the rotational speeds of the electric blowers are close to each other, a humming phenomenon occurs and the noise level fluctuates, making the sound extremely difficult to hear.

The object of the present invention is to provide an operating method that prevents this humming phenomenon and eliminates noise level fluctuations.

[Summary of the invention] When two sounds of approximately equal frequency are synthesized, fh = r
, −f, where fbFi is the frequency, f,
, f represents a general eel frequency with a phonetic expression having approximately the same frequency as #1. Applying this fact, when a device has electric blowers that produce approximately the same sound and are operated at the same time, the number of revolutions of each blower is different, that is, fl and f2 are set to be different, so that the whirring phenomenon does not occur. I made it.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

1. Configuration of Example In Fig. 1, one electric blower is directly connected to the controller 4,
The electric blower 2 connects a resistor 5 in series to the controller 4,
The electric blower 3 has a resistor 6 having a higher resistance value than the resistor 5.
are connected in series to the controller 4. The electric blower having the above configuration is shown in FIG. Main body 7 of electronic copying device
Vc, an exhaust port 8 for exhausting the electric blower l that cools the built-in electronic device section, an exhaust port 9 for exhausting the electric blower 2 that cools the developing device section, and an electric blower 3 that cools the fixing device section. The controller 4, resistor 5, and resistor 6 are also built into the main body. Furthermore, a cassette 11 containing sheets of paper. The cassette 121 is comprised of a paper discharge tray 14 for receiving discharged sheets below a paper discharge port 13 for discharging sheets. Note that the three electric blowers are of the same type.

Explanation of Z operation When the electrophotographic device described above is in a driving state while copying,
The electric blower l is at the rated rotation speed, and the electric blower 2 is operated at a lower rotation speed than the electric blower 1 because the electric power consumed by the resistor 5 is generated and the voltage applied to the electric blower 2 is lower. Electric power consumed by the three blowers and the resistor 6 is generated and is larger than the resistor 5, so the electric blower is operated at a lower rotation speed than the electric blower 2.

3. Effects of Example According to this example, when all three electric blowers are operated at the same rotation speed as in the past, as shown in FIG. When the rotational speeds of the three electric blowers approach each other, the peak sound pressure (d) becomes a beating phenomenon, and the peak sound pressure fluctuates from "b" to "al" and from "d" to "C". As shown in Fig. 4, the rotation speed is different, and as shown in Fig. 4, the peak sound pressure g due to electric blower IVc, the peak sound pressure f++ due to electric blower 2, and the peak sound pressure e and h due to electric blower 3Vc, the frequency is different. The difference is that the whirring phenomenon disappears.

Therefore, it is possible to prevent the humming phenomenon that is difficult to hear.

Specifically, the rotation speed of the electric blower is 328Orpm, the number of blades is 5, the power supply voltage is 24vt+c, and the rated current is 0.1A.
When the resistance of resistor 5 is 20Ω and the resistance value of resistor 6 is 30Ω, the peak sound pressure of electric blower 1 is 273Hz and 546Hz.
, 'IK dynamic blower 2 peak sound pressure 240Hz and 480H
z, the peak sound pressure of electric blower 3 is 220Hz and 440H
Conventionally, there was a constant fluctuation of 43 to 46 dB(A), but according to the present invention, the beat phenomenon was eliminated and the periodic fluctuation became 44 to 45 dBCA).

〔Effect of the invention〕

According to the present invention, the rotational speed of each electric blower can be shifted by simply connecting a resistor, so that the following effects can be obtained.

1. It is possible to prevent the peak sound pressure from beating due to the rotational speed and number of blades of the electric blower, and to eliminate periodic fluctuations in the noise level.

2. Since the electric blower can be of one type, only one type of mounting parts is required, and cost reduction can be expected.

[Brief explanation of drawings]

Figure 1 is a connection circuit diagram between an electric blower and a control device, Figure 2 is an external view of the electronic copying machine, Figure 3 is a noise spectrum diagram of the conventional operating method, and Figure 4 is the operating method of the present invention. FIG. 1-3...Electric blower, 4...Pumper, 5-6...
・Resistor, 7...Main body of electronic copying device, 8-10...
・Exhaust port, 10th 20th

Claims (1)

[Claims] 1. In a device in which a plurality of electric blowers of the same type for cooling are operated simultaneously in one device, the first electric blower is directly connected to a power switch or an operation controller. , the second electric blower is connected to a power switch or controller via a resistor or current limiter, or controls the resistor or current limiter so that the rotation speed is lower than that of the first electric blower. A method of operating an electric blower characterized by having a built-in electric blower. 2. In claim 1, if there is a third electric blower in the device, the power switch is connected via a resistor or current limiter so that the rotation speed is lower than that of the second electric blower. Or a method of operating an electric blower, characterized in that the resistor or current limiter is connected to a controller, or the resistor or current limiter is built into the controller. 3. The method of operating an electric blower according to claim 2, characterized in that when there is a fourth or subsequent electric blower in the apparatus, the number of revolutions is successively lowered.