JP2005235843A - Cooling method and system of electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the clogging of a dustproof filter at an air inlet of a cooling system for an electric machine when air is taken in externally by means of a cooling fan. <P>SOLUTION: In this cooling method of a PDP display 1 comprising a cooling fan 5 for discharging air in the display, and a filter 6 arranged at a second vent opening 8, air is discharged from the second vent opening 8 by rotating the cooling fan 5 reversely as compared with the time of cooling. The cooling system 10 of the PDP display 1 comprises a display unit 2, the cooling fan 5 for discharging air in the display, the filter 6 arranged at the second vent opening 8, and a control section 11 for controlling the rotational direction of the cooling fan 5. The cooling fan control section 11 discharges air from the second vent opening 8 by rotating the cooling fan 5 reversely as compared with the time of cooling under predetermined conditions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present application belongs to a technical field of a cooling method for an electric device and a cooling device for the electric device.

  In a conventional electric device, for example, a CRT (Cathode Ray Tube), the electric circuit is arranged in the back space of the cathode ray tube. However, since the cathode ray tube has a depth and a large back space, heat radiation of the electric circuit has not been a problem. However, thin image display devices such as liquid crystal displays and PDPs (Plasma Display Panels) have a narrow back space, so the electric circuit components must be densely arranged, and the temperature of the electric circuit rises due to heat dissipation of the dense components. Has become a problem.

On the other hand, a technology has been disclosed in which a cooling fan is installed to create an air flow, and warmed air around the electric circuit is discharged to suppress the temperature rise of the apparatus (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-24191

  When the warm air around the electric circuit is forcibly discharged to the outside by the cooling fan, external dust and dust enter from the vent together with the air flowing in from the outside through the vent. Conventionally, a dustproof filter is provided on the surface.

  However, when the cooling fan is operated and air is taken in from the outside for a long period of time, dust and dust may accumulate on the dustproof filter and cause clogging. The dust and dust act as air resistance, hindering sufficient intake of air and failing to secure the air flow, causing an abnormal rise in temperature around the electric circuit.

  Cleaning of the dustproof filter is not so difficult if it is a home or consumer image display device, but in the case of an industrial electric device represented by an industrial image display device such as a large display installed outdoors, Depending on the installation location, it may be difficult to clean the dust filter.

  In the case of an electrical device such as an image display device equipped with a safety device, the safety device works and shuts down the power supply before the temperature rises and affects the components of the electric circuit, so that damage to the device can occur in advance. It is preventing. However, when the image display apparatus is suddenly shut down, the user feels uneasy and uncomfortable.

  An example of a problem to be solved by the present application is to provide a method for removing clogging generated in a dustproof filter by a simple method when air flows in from the outside due to operation of a cooling fan.

  Hereinafter, the present application will be described. In addition, in order to make an understanding of this application easy, the reference sign of an accompanying drawing is attached in brackets, However, This application is not limited to the form of illustration.

  In order to solve the above-mentioned problem, a method for cooling an electric device (1) according to claim 1 includes a cooling fan (5) and a dustproof filter (6) disposed at an inflow position (8) of outside air. The electrical apparatus (1) further includes a rotation control step of rotating the cooling fan (5) in the opposite direction to that during cooling to discharge air from the inflow position (8).

  In order to solve the above-mentioned problem, the cooling device (10) of the electrical device (1) according to claim 9 is arranged in the cooling fan (5) for discharging the air inside the device and the inflow position (8) of the outside air. A dust control filter (6) and a rotation control means (11) for controlling the rotation direction of the cooling fan (5). The rotation control means (11) turns the cooling fan (5) under a predetermined condition. The air is discharged from the inflow position (8) by rotating in the opposite direction to the cooling.

  Next, an embodiment of a cooling method for an electric device according to the present application will be described with reference to the drawings by taking a cooling method for a PDP display device as an example of an image display device as an example.

  FIG. 1 is a longitudinal sectional view of a PDP display device according to an embodiment of the present application, and FIG. 2 is a block diagram of a cooling device of the PDP display device according to an embodiment of the present application.

  The PDP display device 1 includes a display unit 2, an electric circuit 3 that is disposed on the back surface of the display unit 2 and supplies power, video signals, and audio signals, a cover 4 that covers the electric circuit 3, and the like. A cooling fan 5 that discharges air inside the apparatus that has been warmed by heat radiation, and a filter 6 that is disposed in a second vent 8 through which air flows into the space covered by the cover 4 are provided.

  Further, in FIG. 2, the cooling device 10 of the PDP display device 1 includes a cooling fan control unit 11 that controls the rotation of the cooling fan 5 and a cooling fan drive unit 12 that rotates the cooling fan 5. 1 is housed.

  The display unit 2 includes, for example, a plasma display panel and a speaker, and receives video signals and audio signals and outputs video and audio.

  The electric circuit 3 includes a power supply circuit that supplies power to the entire apparatus, a drive circuit that causes discharge in each cell of the plasma display panel, and a signal circuit that transmits a video signal and an audio signal. Located on the back.

  The cover 4 is made of, for example, plastic or a steel plate, and covers the electric circuit 3 so that dust does not enter the apparatus. In addition, the electric circuit 3 emits an electromagnetic wave and does not affect surrounding electronic devices. Plays a shielding role. The cover 4 has a first vent 7 and a second vent 8 at the position of the cooling fan 5 and the position of the filter 6, respectively.

  The cooling fan 5 is fixed to the first vent 7 disposed above the cover 4 and discharges the air in the apparatus heated by heat radiation.

  The filter 6 is fixed to the second vent hole 8 disposed at the lower part of the cover 4. When the cooling fan 5 discharges air from the first vent 7, the filter 6 prevents intrusion of dust that flows together with air from the second vent 8.

  The cooling fan control unit 11 includes, for example, a CPU (Central Processing Unit) 21, a memory 22, a counter 23, and the like, monitors the operation of the cooling fan 5, and controls the power supplied to the cooling fan 5. 5 is controlled.

  The cooling fan drive unit 12 includes a switch 24, an amplifier 25, and the like, and rotates the cooling fan 5.

  Here, for example, the PDP display device 1 according to the present embodiment is the electrical device according to the present application and the image display device according to the present application, the display unit 2 is the image display means according to the present application, and the cooling fan 5 is the cooling fan according to the present application. The filter 6 is the dustproof filter according to the present application, the second vent 8 is the inflow position according to the present application, the cooling device 10 is the cooling device according to the present application, and the cooling fan control unit 11 is the rotation control means according to the present application. Configure each.

  The operation of the cooling device 10 of the PDP display device 1 having the above configuration will be described below.

  When the PDP display device 1 is energized for a long time and the electric circuit 3 is heated and the air around it is warmed, the cooling fan 5 operates to discharge the air around the electric circuit 3.

  The operation at this time will be described in more detail. Since the air around the electric circuit 3 is not warmed when the power is turned on and thereafter for a certain period of time, the cooling fan 5 does not operate to ensure quietness. However, when a predetermined time, for example, 30 minutes elapses after the power is turned on, the air around the electric circuit 3 is gradually warmed, so that the CPU 21 of the cooling fan control unit 11 performs the first operation on the switch 24 of the cooling fan drive unit 12. And the cooling fan 5 is rotated to discharge air. At this time, for example, the cooling fan 5 is controlled by the cooperation of the cooling fan control unit 11 and the cooling fan drive unit 12 so as to gradually increase the rotational speed in accordance with the temperature rise of the air in the apparatus. The number of revolutions of the cooling fan 5 is controlled by the CPU 21 and the counter 23 of the cooling fan control unit 11.

  A self-cleaning method performed by the cooling device 10 of the PDP display device 1 that performs the above operation will be described below.

  When the PDP display device 1 is operated for a long time and the cooling fan 5 continues to discharge air, dust accumulates on the filter 6 attached to the second vent 8. In particular, more dust accumulates on the outer surface of the filter 6. Since this dust acts as an air resistance, the air discharge capacity of the cooling fan 5 gradually decreases with the passage of the use period and the accumulation of dust. That is, if dust accumulates on the filter 6, even if the cooling fan 5 is rotated, a sufficient air flow cannot be formed in the apparatus, and as a result, the temperature of the air in the apparatus does not decrease.

  Under such circumstances, the self-cleaning method performed by the cooling device 10 of the PDP display device 1 is as follows.

  The cooling fan control unit 11 always keeps track of the rotation time of the cooling fan 5 and stores the accumulated rotation time in the memory 22. When the cumulative rotation time of the cooling fan 5 exceeds the cumulative rotation determination time, the cooling fan control unit 11 accumulates dust on the filter 6, and the amount of inflowing air is reduced so that a sufficient amount around the electric circuit is obtained. It is judged that the air flow cannot be formed. Then, a command is issued to the cooling fan drive unit 12 to reversely rotate the cooling fan 5 for a predetermined time.

  Specifically, the second control signal output from the CPU 21 is amplified by the amplifier 25 and the cooling fan 5 is rotated in the reverse direction.

  When the cooling fan 5 rotates in the reverse direction, air flows into the device from the first vent 7 and air is discharged from the second vent 8 to the outside. Thereby, the dust accumulated on the outer surface of the filter 6 is pushed out and removed by the air discharged from the inside of the PDP display device 1.

  After the cooling fan 5 performs reverse rotation for a predetermined time, the cooling fan control unit 11 resets the accumulated rotation time of the cooling fan 5 and starts recording the accumulated rotation time again.

  Here, the value of the cumulative rotation determination time, which is the determination of the reverse rotation of the cooling fan 5, depends largely on the installation environment of the PDP display device 1, so it cannot be generally stated, but in an environment with little dust, for example, It is about 10,000 hours. This cumulative rotation determination time is designed so that it can be changed in consideration of the installation environment.

  In addition, the operating condition when the cooling fan 5 is reversely rotated to remove dust accumulated on the filter 6 is determined by experiment. This is because the dust removal capability required depends on the arrangement of the electric circuit 3 in the internal space and the size of the internal space. The reverse rotation operation condition includes the reverse rotation time in addition to the power (voltage, rotation speed, rotation speed) to the cooling fan 5.

  The position and number of the second vent holes 8 are determined from the original purpose of securing an amount of air necessary and sufficient for cooling the electric circuit 3, and in the present application, the cooling fan 5 is rotated in the reverse direction. Sometimes it is necessary to be in a position and number where dust can be removed efficiently. This is related to the position and number of the first vent holes 7, the arrangement of the electric circuit 3 in the internal space, and the like, and is determined by experiments.

  The self-cleaning method of the cooling device 10 of the PDP display device 1 described above will be described below with reference to FIG. FIG. 3 is a flowchart showing a self-cleaning method of the cooling device 10 of the PDP display device 1.

  When the power of the PDP display device 1 is turned on (START), the cooling fan control unit 11 confirms the cumulative rotation time of the cooling fan 5 stored in the memory 22 at the previous device stop (step S1).

  When the accumulated rotation time does not exceed the accumulated rotation determination time (step S1: Y), the PDP display device 1 moves to a normal operation (step S2). That is, the cooling fan control unit 11 does not rotate the cooling fan 5 until a predetermined time elapses after the power is turned on, but the cooling fan control unit 11 starts rotating the cooling fan 5 when the predetermined time elapses. The cooling fan control unit 11 controls the rotational speed of the cooling fan 5 so as to gradually increase as the temperature in the apparatus rises. In the cooling fan control unit 11, the CPU 21 stores the rotation start time of the cooling fan 5 in the memory 22 and monitors the accumulated rotation time.

  When the accumulated rotation time exceeds the accumulated rotation determination time (step S1: N), the cooling fan control unit 11 issues a command to the cooling fan driving unit 12 to rotate the cooling fan 5 in the reverse direction for a predetermined time and deposit it on the filter 6. Dust is removed (step S3).

  After the predetermined time has elapsed and the reverse rotation is completed, the cooling fan control unit 11 resets the accumulated rotation time of the cooling fan 5 stored in the memory 22 (step S4), and again records the accumulated rotation time. (Step S2), since the power is not turned off (Step S5: N), the process returns to the cumulative rotation time determination step (Step S1).

  When the power is turned off (step S5: Y), the end process is started (step S6). That is, the cooling fan control unit 11 calculates the rotation time and cumulative rotation time of the cooling fan 5 from the time when the power is turned off and the rotation start time of the cooling fan 5 recorded in the memory 22, and stores the cumulative rotation time in the memory. Record in 22 and end (END).

  Next, another circuit configuration of the cooling fan driving unit 12 for realizing the cooling device 10 of the PDP display device 1 will be described with reference to FIG. FIG. 4 shows an example of another circuit configuration of the cooling fan drive unit 12.

  The cooling fan drive unit 12 shown in FIG. 2 determines the rotation direction of the cooling fan 5 using the second control signal output from the CPU 21, whereas the cooling fan drive unit 12 shown in FIG. The two switches 26 and 27 are switched by the third control signal output from the CPU 21 to determine the rotation direction of the cooling fan 5.

The above embodiment has the following effects.
Since normal air flows from the second vent 8 through the filter 6 to the periphery of the electric circuit 3, much dust accumulates on the outer surface of the filter 6. Since the air is discharged from the inside of the PDP display device 1 through the filter 6 by the reverse rotation of the cooling fan 5, the dust accumulated on the outer surface of the filter 6 is discharged by the air discharged from the inside of the device. Extruded and removed. Therefore, the air resistance at the filter 6 is reduced, and the air discharge capacity of the cooling fan 5 and the cooling capacity of the cooling device 10 are restored.
● The cumulative rotation judgment time can be changed, so the cumulative rotation judgment time can be determined in consideration of the installation environment. Since the amount of dust varies greatly depending on the installation environment, the accumulated rotation judgment time can be determined and changed by observing the degree of dust accumulation after installation.
● Since the number of rotations of the cooling fan 5 is controlled to gradually increase as the temperature around the electric circuit 3 rises, it is possible to reduce the rotation noise of the cooling fan 5 when the cooling fan 5 is stationary and at low speed operation. It is possible to reduce the discomfort given to the user and to reduce the power consumption of the cooling fan 5.

In addition, the said embodiment is not limited above, For example, you may deform | transform as follows.
In the above embodiment, whether or not the filter 6 is clogged is determined by the accumulated rotation determination time. However, the accumulated rotation determination time does not have to be a constant value, and dust removal It may be changed by the number of times. That is, in the initial operation (START), the number of past dust removals (the number of past reverse rotations) is grasped, and when the reverse rotation is performed in the past, the cumulative rotation determination time is shorter than the previous cumulative rotation determination time. You may make it instruct | indicate reverse rotation. Since the dust is not removed to the same level as the new filter 6 in the first reverse rotation, the accumulated rotation judgment time after the second time is reduced and clogged to the same degree as the first reverse rotation. This is because the second and subsequent reverse rotations are performed. For the same reason, the rotation time of the second and subsequent reverse rotations may be set longer than the rotation time of the first reverse rotation of the cooling fan 5.
In the above embodiment, the cooling fan 5 immediately reversely rotates when the cumulative rotation time of the cooling fan 5 exceeds the cumulative rotation determination time. However, the present invention is not limited to this, and at least the first after the cumulative rotation determination time is exceeded. The cooling fan 5 may be rotated in the reverse direction when the PDP display device 1 is finished or started. Rather than a sudden reverse rotation during operation of the PDP display device 1, the user's anxiety can be eliminated by performing it at a predetermined timing, such as at the end operation or at the start operation.
○ In the above embodiment, the cooling fan 5 is controlled to rotate in the reverse direction when the accumulated rotation determination time is exceeded, but at least every time of start-up operation or end operation regardless of the accumulated rotation time of the cooling fan 5 The cooling fan 5 may be reversely rotated for a predetermined time. By removing the dust from the filter 6 every time the starting operation is performed, it is possible to reduce the fluctuation of the substantial air discharge capacity of the cooling fan 5 and to reduce the temperature change of the electric circuit. In addition, by always rotating in reverse at the same timing, it is possible to predict the generation of the rotation sound of the cooling fan and to eliminate the user's anxiety. Furthermore, fluctuations in the rotational load of the cooling fan 5 can be reduced, and the life of the cooling fan 5 can be extended.
The cooling fan control unit 11 may grasp the accumulated rotational speed of the cooling fan 5 and control the cooling fan 5 to reversely rotate when the cumulative rotational speed exceeds a predetermined number. This is because air is discharged in proportion to the cumulative number of rotations of the cooling fan 5 and dust is accumulated on the filter 6. In addition to counting the cumulative number of rotations by the counter 23 and the CPU 21, the cumulative number of rotations can also be obtained by grasping and converting the rotation start time and stop time of the cooling fan 5.
A thermometer 9 such as a thermocouple as an example of a temperature measuring means for measuring the temperature around the electric circuit 3 is provided, and cooling is performed when the temperature around the electric circuit 3 does not fall to a predetermined temperature even when the cooling fan 5 is rotated. The fan control unit 11 may be configured to rotate the cooling fan 5 in the reverse direction. This is because it can be determined that dust has accumulated on the filter 6 when the temperature around the electric circuit 3 does not decrease even when the cooling fan 5 is rotated. Further, from the relationship between the temperature change around the electric circuit 3 when the cooling fan 5 rotates, the temperature, the rotation of the cooling fan 5 and the power consumption, the amount of dust in the installation environment and the clogging of the filter 6 are determined to determine the cumulative rotation. It is also possible to determine the time and issue a reverse rotation command based on the value. The thermometer 9 is desirably arranged in the vicinity of a part that is most easily damaged by heat among the parts of the electric circuit 3 in addition to being arranged in a place where the temperature is highest in the periphery of the electric circuit 3.
○ Communicate with other devices such as air conditioners and air purifiers that have the function of detecting dust in the air, and determine the accumulated rotation judgment time by obtaining the amount of dust in the installation environment from other devices. Also good. Since the accumulated rotation determination time can be determined based on data from a device that actually observes dust in the air, the burden on the user can be reduced. Examples of the communication means include BLUETOOTH (IEEE: The Institute of Electrical and Electronics Engineers 802.15 / registered trademark: registration number 4623573).
In the above embodiment, the image display device has been described as an example. However, with respect to an electric device such as a personal computer (PC) in which the electric circuit is concentrated and the temperature rise is concerned by making the electric device thin. However, the present application is applicable.

FIG. 1 is a longitudinal sectional view of a cooling device 10 of a PDP display device 1 according to an embodiment of the present application. FIG. 2 is a block diagram of the cooling device 10 of the PDP display device 1 according to an embodiment of the present application. FIG. 3 is a flowchart showing a self-cleaning method of the cooling device 10 of the PDP display device 1 according to an embodiment of the present application. FIG. 4 is a diagram illustrating an example of another circuit configuration of the cooling fan driving unit 12 of the PDP display device according to the embodiment of the present application.

Explanation of symbols

1: PDP display device 2: Display unit 5: Cooling fan 6: Filter 8: Second vent 9: Thermometer 10: Cooling device 11: Cooling fan controller

Claims (10)

In a method for cooling an electric device comprising: a cooling fan that discharges internal air; and a dustproof filter disposed at an inflow position of outside air for cooling,
A method for cooling an electric device, comprising: a rotation control step of rotating the cooling fan in a direction opposite to that during cooling to discharge air from the inflow position. In the cooling method of the electric equipment according to claim 1,
In the rotation control step, when the cumulative rotation time of the cooling fan reaches a predetermined value, the cooling fan is rotated in the reverse direction. In the cooling method of the electric equipment according to claim 2,
In the rotation control step, the cooling fan is reversely rotated at least at the time of the first apparatus stop or the first apparatus start-up after the cumulative rotation time reaches the predetermined value. How to cool the device. In the cooling method of the electric equipment according to claim 1,
In the rotation control step, when the cumulative number of rotations of the cooling fan reaches a predetermined value, the cooling fan is rotated in the reverse direction. In the cooling method of the electric equipment according to claim 4,
In the rotation control step, the cooling fan is reversely rotated at least at the time of the first stop of the electric device or the first start-up of the electric device after the cumulative rotation number reaches the predetermined value. A method for cooling an electric device. In the cooling method of the electric equipment according to claim 1,
In the rotation control step, the cooling fan is reversely rotated at least when the electric device is stopped or when the electric device is started. In the cooling method of the electric equipment according to claim 1,
The electrical apparatus includes temperature measuring means for measuring the temperature in the apparatus,
In the rotation control step, when the temperature measuring means measures that the temperature in the apparatus does not drop to a predetermined temperature even when the cooling fan is rotated, the cooling fan is rotated in reverse. Method for cooling an electric device. In the cooling method of the electric equipment according to any one of claims 1 to 7,
The electrical apparatus is an image display apparatus having an image display means. A cooling fan that exhausts the internal air;
A dust-proof filter arranged at an inflow position of outside air for cooling;
Rotation control means for controlling the rotation direction of the cooling fan;
In the cooling device of the electric device having
The rotation control means rotates the cooling fan under a predetermined condition in the opposite direction to cooling and discharges air from the inflow position;
A cooling device for an electric device characterized by that. The cooling device for an electric device according to claim 9,
The electrical apparatus is an image display apparatus having an image display means.

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