JPH03102175A - Inspection device for refrigerator - Google Patents

Abstract

PURPOSE:To inspect the malfunction of a fan even in a place where a background noise is loud by measuring the vibration of the outer wall of a refrigerator. CONSTITUTION:In a case where the malfunction of a fan 5 is inspected by the title inspection device 8, the vibration of the rear surface 1a of a refrigerator, which arises during the operation of the refrigerator, i.e., during the drive of the fan 5, is received by a vibration pickup 10 and measured by a vibration meter 9. The frequency analysis of an output signal released from the vibration meter 9 is then made by a frequency analyzer 11. The reference value of a vibration level in a predetermined frequency and the measured value are compared with each other by a decision means 12 to judge the malfunction. Accordingly, the reference value of decision of the vibration level is set in advance in the decision means 12 from the frequency analysis result obtained by measuring the vibration in advance during a normal operation. By comparing the reference value with an output value obtained from the frequency analyzer 11, the malfunction is decided if the output value exceeds the reference value. Accordingly, the malfunction of the fan 5 can be inspected even in a place where a background noise is loud.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a refrigerator inspection device for inspecting whether or not there is an abnormality in a cold air circulation fan provided within the refrigerator body.

(Prior Art) In a refrigerator, as shown in FIG. Some devices are configured to circulate and supply cold air to the freezer compartment 2 and the refrigerator compartment 3.

However, in such a refrigerator, the fan 5 may not function properly due to an assembly error or the like.

Types of abnormalities in the fan 5 include the fan 5 being locked, the stator of the motor 5a of the fan 5 not being properly fixed to the bracket, and the fan 5 rotating in the opposite direction. If the refrigerator is used with such an abnormality in the fan 5, the cooling operation may not be performed normally. However, since the fan 5 is disposed inside the main body 1, it is not easy to inspect whether there is any abnormality after the fan 5 is assembled.

Therefore, in recent years, it has been considered to indirectly check whether there is any abnormality in the fan 5 by measuring the noise of the fan 5 from outside the refrigerator. This is based on the fact that if the fan 5 has the above-mentioned abnormality, abnormal noise will be generated when the fan 5 is driven.Therefore, the abnormality of the fan 5 is determined by inspecting the presence or absence of abnormal noise. It is possible.

(Problem to be Solved by the Invention) By the way, on a refrigerator production line, the cooling performance of the refrigerator is inspected by operating the refrigerator for about several tens of minutes. On the other hand, it was difficult to inspect the fan 5 described above on the production line for the following reasons. That is, since the fan 5 is disposed inside the refrigerator main body 1, its noise level is low, and therefore, its measurement can only be carried out in a place with low background noise. On the other hand, on a production line, the background noise is much louder, so measuring it requires large-scale equipment such as soundproof walls spanning the line and suspended structures to block low frequencies. becomes necessary. Furthermore, since the production line must be temporarily stopped for the measurement, there is a problem in that a large amount of time is lost due to this.

For this reason, in the past, the fans 5 were actually only inspected by sampling, for example, and not all of them were inspected.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a refrigerator that can inspect whether there is any abnormality in the fan even in a place with a lot of background noise, and that can be completed with a simple configuration. To provide inspection equipment.

[Structure of the Invention] (Means for Solving the Problems) The refrigerator inspection device of the present invention includes a vibration meter that measures the vibration of the outer wall surface when a fan is operating using a vibration pickup attached to the outer wall surface of the refrigerator; A frequency analyzer performs frequency analysis of the vibrations measured by the vibration meter, and the vibration level at a predetermined frequency analyzed by this frequency analyzer or the overall value of the vibration level is compared with a preset normal value. The present invention is characterized in that it includes a determining means for determining whether or not there is an abnormality in the fan.

(Function) As a result of various experiments and research, the inventors of the present invention have found that the locked state of the fan and the poor fixation between the stator and bracket of the fan motor caused abnormal noise. We have now confirmed that fan abnormalities such as reverse rotation of the fan can be detected by measuring vibrations on the outer wall of the refrigerator. This is because when frequency analysis of the measured vibrations is performed, it is found that when the fan is abnormal, the vibration level at a predetermined frequency that is a multiple of the power supply frequency stands out significantly compared to the normal vibration level, or the vibration level This can be determined from the fact that the overall value increases several times.

Therefore, according to the above means, it is possible to indirectly check whether there is any abnormality in the fan by measuring the vibration of the outer wall surface of the refrigerator. In this case, since we are not measuring noise,
Measurements can be made even in places with extremely high background noise, and large-scale equipment such as soundproof walls or suspended structures is not required.

(Example) An example of the present invention will be described below with reference to the drawings.

First, the general structure of the refrigerator is as shown in FIG.
A cooler 4 and a fan 5 are disposed on the back side of the freezer compartment 2. Furthermore, a machine room 7 in which a compressor 6 and the like are housed is provided at the bottom of the main body 1. The fan 5 is constructed by attaching blower blades 5b to a fan motor 5a, and is configured to circulate and supply cold air from the cooler 4 to the freezer compartment 2 or the refrigerator compartment 3.

Now, a device for inspecting the presence or absence of abnormality in the fan 5 will be described with reference to FIG.

The inspection device 8 according to this embodiment is configured by the following system. That is, 9 is a vibration meter, which in this case is a vibration accelerometer, and is configured to process the output signal from the vibration pickup 10 that receives the vibration of the object to be measured and output it as an acceleration signal. As will be described later, the vibration pickup 10 is detachably attached to the rear surface 1a, which is the outer wall surface of the main body 1 of the refrigerator, using a magnet, for example.
It is designed to receive vibrations from the back surface 1a. Reference numeral 11 denotes a well-known digital frequency analyzer, which performs frequency analysis of the output signal from the vibration meter 9 by FFT (Fast Fourier Transform). Reference numeral 12 denotes a determining device as a determining means, which is composed of, for example, a microcomputer. Based on the analysis by the frequency analyzer 11, as will be described in detail later, the vibration level at a predetermined frequency or the overall value of the vibration level is compared with a preset normal value to determine whether the fan 5 is abnormal. The presence or absence is determined and the determination result is displayed or notified.

Next, a procedure for testing whether or not there is an abnormality in the fan 5 using the testing device 8 configured as described above will be described.

Refrigerators are tested for cooling performance on the production line.
At the same time, an inspection by the inspection device 8 is performed. This inspection is carried out by attaching the vibration pickup 10 to the back surface 1a of the main body 1 of the refrigerator and operating the refrigerator in this state, as shown in FIG. The inspection device 8 is the second
As shown in the figure, first, the vibration of the back surface 1a during operation of the refrigerator, that is, when the fan 5 is driven, is received by the vibration pickup 10 (
a), measured by a vibrometer 9 (b). Next, frequency analysis of the output signal from the vibration meter 9 is performed by the frequency analyzer 11 (c). Then, the determination device 12 compares the reference value of the vibration level at a predetermined frequency with the measured value to determine whether there is an abnormality (d).

FIGS. 3 to 6 show the frequency analysis results of vibration measurements made by the inventors. It should be noted that these analysis results were obtained during operation at a power supply frequency of 60 Hz.

FIG. 3 shows the frequency characteristics of vibration of the fan 5 during normal operation.

FIG. 4 shows the frequency characteristics of vibration when the fan 5 is in a locked state. Compared to the normal time above, the frequency is 60
It can be seen that the vibration level is outstanding at 0Hz.

FIG. 5 shows the frequency characteristics of vibration when the stator of the fan motor 5a and the bracket are not fixed properly.

It can be seen that the vibration level stands out at a frequency of 360 Hz when compared with the above normal state.

FIG. 6 shows the frequency characteristics of vibration when the fan 5 rotates in reverse. When compared with the above-mentioned normal state, it can be seen that the overall value of the vibration level is about three times as high, and that the vibration level stands out at a frequency of 628 Hz.

Therefore, the determination device 12 determines, for example, a frequency of 360Hz. 600Hz
A reference value for determining the vibration level at 628 Hz is set in advance. Then, the reference value and the frequency analyzer 11
By comparing the output value with the output value, it is determined that there is an abnormality if the output value exceeds the reference value.

In this way, according to this embodiment, the back surface 1a of the refrigerator main body 1
By measuring the vibration of the fan 5, it is possible to check whether there is any abnormality in the fan 5 after assembly.

Therefore, unlike the conventional method in which inspection is performed by measuring noise, it is possible to inspect whether or not there is an abnormality in the fan 5 even in a place where there is a lot of background noise. Further, large-scale equipment such as a soundproof wall or a suspended structure is not required, and a simple system configuration such as a vibration meter 9, a frequency analyzer 10, and a determination device 11 can be used. Moreover, since the fan 5 can be inspected simultaneously with the cooling performance inspection on the production line, the inspection can be carried out extremely efficiently in terms of time.

It should be noted that the present invention is not limited to the above embodiments; for example, the reverse rotation of the fan 5 may be determined by comparing the overall values of the vibration levels, and changes may be made as appropriate without departing from the scope of the invention. It can be implemented by

[Effects of the Invention] As is clear from the above explanation, according to the refrigerator inspection device of the present invention, it is possible to detect whether there is an abnormality in the fan for circulating cold air by measuring the vibration of the outer wall of the refrigerator. Therefore, it is possible to check whether there is an abnormality in the fan even in a place with a lot of background noise, and it has an excellent effect that it can be completed with a simple configuration.

[Brief explanation of drawings]

Figures 1 to 6 show one embodiment of the present invention. Figure 1 is a diagram schematically showing the overall configuration, Figure 2 is a diagram showing the inspection procedure, and Figure 3 is a diagram showing the normality of the fan. Figure 4 is a frequency characteristic diagram of the vibration level when the fan is in a locked state. Figure 5 is a frequency characteristic diagram of the vibration level when the fan motor stator and bracket are not fixed properly. The figure is a frequency characteristic diagram of the vibration level when the fan rotates in reverse, and FIG. 7 is a longitudinal sectional side view of a general refrigerator that is the object of measurement in the present application. In the drawing, 1 is the main body, 1a is the back (outer wall surface), 5 is the fan, 5a is the fan motor, 8 is the inspection device, 9 is the vibration meter, 1
0 is a vibration pickup, 11 is a frequency analyzer, and 12 is a determination device (determination means). Figure 2 Umaki (Hz) Figure 6 Figure 7

Claims (1)

[Claims] 1. A refrigerator having a fan for circulating cold air inside the main body, which inspects the presence or absence of an abnormality in the fan,
A vibration meter that measures the vibration of the outer wall surface of the refrigerator when the fan is in operation using a vibration pickup attached to the outer wall surface of the refrigerator, a frequency analyzer that analyzes the frequency of the vibration measured by the vibration meter, and the frequency analyzer. and a determination means for determining whether or not there is an abnormality in the fan by comparing the vibration level at a predetermined frequency or the overall value of the vibration level analyzed by the fan with a preset normal value. inspection equipment.