JPH10122716A - Cooling fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling fan which detects a drop of air flow from the outlet side of the air of itself caused by the clogging of the dust filter installed on the air suction side of itself and outputs an alarm immediately. SOLUTION: When a dust filter 6 is clogged, even if the fan body 1 is rotating at a certain rotational speed, the wind of an air current B blown out of the fan body 1 through the dust filter 6 decreases, and the rotational speed of the rotary vanes 41 of a sensor unit decreases. A marker 5 comes to the same position in the same cycle if the rotational speed of the sensor unit rotary shaft 42 is constant, so if a stroboscope 8 is made to emit light, being synchronized with the cycle, the marker 5 is seen standing still at the same position, but as the rotational speed of the rotary vanes 41 of the sensor unit decreases due to the clogging of the dust filter 6, the marker 5 is seen moving as if it flows. The movement of the marker 5 is detected with a monitor camera 9, and the image signal from the monitor camera 9 at this time is converted into an electric signal with a sensor circuit 10, and is outputted as an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cooling fan,
In particular, the present invention relates to a cooling fan for cooling a communication device or the like which immediately issues an alarm when a dust filter is clogged and prompts the user to clean or replace the dust filter.

[0002]

2. Description of the Related Art In recent years, in a communication apparatus, the speed of operation of a device in a unit to be used and the mounting density have been increased, and the power consumption tends to increase accordingly. For this reason, the conventional natural air cooling system using convection of air cannot provide sufficient cooling, and a forced air cooling system that mounts a fan and rotates it to cool the devices in the unit with the airflow generated is used. Use cases are increasing.

Conventionally, this type of cooling fan used in a communication device is composed of rotating blades and an outer frame surrounding the blades, and supplies a constant amount of air by keeping the rotation speed of the blades constant. It has a structure to do.

[0004] However, in this cooling fan, when the fan sucks air, dust in the air is sucked together, and the dust that has been sucked in on the printed circuit board in the unit to be cooled during a long period of use. Deposited on
Conductive materials such as metal contained in the accumulated dust,
In some cases, a short circuit accident between patterns on a printed circuit board occurs due to moisture or salt due to insect excrement.

For this reason, recently, a dust filter has been installed on the intake side of the fan to remove dust in the intake air of the fan and to send clean air into the unit. I have.

However, if the cooling fan with the dustproof filter has been used for a long period of time, dust adheres to the dustproof filter and causes clogging. As a result, the amount of intake air, and therefore the amount of air sent to the unit to be cooled, decreases, and it is not possible to sufficiently cool the heat-generating printed circuit board. There was also.

Therefore, a method has been proposed in which clogging of the dust-proof filter is detected and the maintenance person is notified of the replacement time of the dust-proof filter.

As first and second conventional examples of this type of technique, a "cooling fan" described in JP-A-6-61672 and a "cooling mechanism" described in JP-A-4-60981 are disclosed. Can be mentioned.

[0009]

In this first conventional example, a change in the amount of air blown by a fan is linked to the operation of a switch contact, and the clogging of a dustproof filter is quantitatively detected to output an alarm to the outside. ing.

In the second conventional example, the state of clogging of the cooling air purifying filter is constantly monitored by the air pressure introduced into the apparatus to indicate whether or not air is normally introduced. .

Therefore, the maintenance person notices that the dustproof filter is clogged by an alarm or display and replaces the filter. However, the unit to be cooled has a difference in the amount of dust deposited on the dustproof filter depending on the installation environment. Because the filter replacement time cannot be specified, the problem is that the heat-generating printed circuit board cannot be cooled sufficiently unless the dust filter is cleaned or replaced immediately after clogging occurs. there were.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling fan which detects a decrease in air flow from the air outlet side of a fan caused by clogging of a dust filter installed on the air intake side of the fan and immediately issues an alarm. Is to do.

[0013]

According to the present invention, the fan is installed on the air blowing side of a fan that generates an air flow by rotation of the first blade, and is rotated by the air flow discharged from the fan. A cooling fan characterized by including a second blade and a sensor unit that detects a change in the rotation speed of the second blade and issues an alarm is obtained.

A fan body mounted below the unit to be cooled to cool the heat generating device in the unit to be cooled; a dust filter installed on an air suction side of the fan body; And a sensor unit having the second blade mounted on an air blowing side and rotated by an airflow discharged from the fan body.

Further, the sensor unit has a sensor unit rotating shaft having one marker for detecting the number of rotations, a sensor unit rotating blade serving as the second blade, and emits light at a predetermined period toward the marker. A cooling fan comprising: a stroboscope; a monitoring camera that detects the movement of the marker; and a sensor circuit that converts an image signal sent from the monitoring camera that detects the movement of the marker into an electric signal. Is obtained.

Still further, the sensor circuit issues an alarm indicating that the dust filter is clogged only when the image signal indicating that the marker is moving is input from the monitoring camera. Is obtained.

[0017]

Next, the present invention will be described with reference to the drawings.

First, the operation of the present invention will be described.
In the present invention, the sensor unit detects a change in the number of rotations of the blades that rotate in response to the airflow generated by the fan. When the dust filter installed on the side clogs and the amount of air sucked into the fan, and thus the amount of air blown out from the fan, decreases, the number of rotations of the blades rotated by the air flow decreases. The change in the number of rotations can be detected by the sensor unit.

When the sensor unit detects a change (decrease) in the number of rotations of the blades, an alarm is issued immediately to prevent the temperature inside the unit from rising due to a decrease in the air flow rate, and to prevent the device on the printed circuit board from malfunctioning. And system down due to destruction can be prevented.

Next, an embodiment of the present invention will be described.

FIG. 1 is a sectional view showing a state in which a dustproof fan is not clogged in one embodiment of a cooling fan of the present invention. FIG. Indicates the status being sent to the unit,
FIG. 2B is a diagram showing a state in which air is being smoothly blown to the sensor unit in the state shown in FIG. FIG. 2 is a cross-sectional view showing a state in which the dustproof fan is clogged in one embodiment of the cooling fan of the present invention.
(A) shows a state where a prescribed air flow rate is not sent to the unit to be cooled even though the fan is rotating at a constant speed, and (b) shows a state where the sensor unit rotating blades are in the state shown in FIG. FIG. 7 is a diagram showing a state where a specified number of rotations cannot be obtained.

In the cooling fan of the present embodiment, the fan body 1 that cools the heat-generating device on the printed circuit board is normally mounted in order to maintain the normal operation of the devices on the printed circuit board (not shown) mounted on the unit 7 to be cooled. It is mounted below the cooling unit 7 and has a structure in which the air sucked by the fan body 1 is blown out to the unit to be cooled 7.

A dust filter 6 is installed on the air suction side of the fan in order to remove dust in the air sucked by the fan body 1, and clean air removed by the fan is passed through the fan body 1 to the unit 7 to be cooled. Be blown out.

A sensor unit 4 having sensor unit rotating blades 41 is mounted on the air outlet side of the fan body 1. Since the sensor unit 4 does not have a power source, the sensor unit rotating blades 41 cannot rotate by themselves, but rotate by the airflow blown from the other.

That is, the cooling fan according to the present embodiment includes a dustproof filter 6, a fan body 1 that sucks air through the dustproof filter 6 by the rotation of a fan rotating blade 3 provided on the fan rotating shaft 2, and a fan body 1. Sensor unit rotating blade 4 rotated by the blown air flow
1 and a sensor unit 4 having the same. The sensor unit 4 includes a sensor unit rotation shaft 42 on which a rotation detection marker 5 is displayed at one position, a sensor unit rotation blade 41, a stroboscope 8 that emits light at a constant period toward the marker 5, It comprises a monitoring camera 9 for detecting the movement of the marker 5 and a sensor circuit 10 for converting an image signal sent from the monitoring camera 9 for detecting the movement of the marker 5 into an electric signal.

First, referring to FIG. 1, during operation of the communication device, the fan rotating blades 3 rotate to supply cooling air to the unit to be cooled in order to cool the heat generating device in the unit and operate the communication device normally. 7, the unit cooling air sucked from the outside by the fan main body 1 flows through the dustproof filter 6, and the air flow A causes the sensor unit 4 installed on the air blowing side of the fan main body 1 to blow. The sensor unit rotating blades 41 are rotated.

The rotation speed of the sensor unit rotating blades 41 changes according to the amount of air blown from the fan body 1.

For example, when dust is accumulated on the dustproof filter 6 due to long-term use of the cooling fan and the dustproof filter 6 becomes clogged as shown in FIG. 2, the fan rotating blades 3 rotate at a steady rotational speed. Even if it rotates, the airflow of the airflow B passing through the dustproof filter 6 is smaller than the airflow of the airflow A shown in FIG. Therefore, the amount of air sent into the sensor unit 4 also decreases, and the rotation speed of the sensor unit rotary blade 41 decreases.

Then, as shown in FIG. 2A, when the dust-proof filter 6 is clogged, the fan body 1 passes through the dust-proof filter 6 even though it is rotating at a constant speed. At the same time as the air volume decreases, the fan body 1
The airflow of the airflow B blown from the fan body 1 also decreases, and the rotation speed of the sensor unit rotary blade 41 rotated by the air blown from the fan body 1 decreases.

As described above, the rotation number detecting marker 5 is displayed at one position on the sensor unit rotation shaft 42 of the sensor unit 4, and the rotation speed of the sensor unit rotation shaft 42 is constant. Then, in order to come to the same position in the same cycle, the stroboscope 8
Makes the marker 5 look stationary at the same position.

For example, when the fan main body 1 is rotating at a constant speed of 600 revolutions / minute, the marker 5 on the surface of the sensor unit shaft 42 passes through the same location 10 times per second. If the stroboscope 8 emits light 10 times per second in synchronization with the moment when the marker 5 passes, the light emission cycle of the stroboscope 8 matches the passing cycle of the marker 5,
As shown in FIG. 1B, the marker 5 is stationary and looks like a single point.

Although the light emission cycle of the stroboscope 8 is constant, the amount of airflow B blown out from the fan body 1 is reduced due to the clogging of the dustproof filter 6, and the rotation of the sensor unit rotating blades 41 is accordingly caused. When the number decreases, the passage period of the marker 5 on the surface of the sensor unit rotation shaft 42 and the light emission period of the stroboscope 8 slightly shift, so that the marker 5 is stopped as shown in FIG. It appears to flow without.

In this embodiment, the monitoring camera 9 monitors whether the marker 5 is moving or stationary, and the monitoring camera 9 detects the movement of the marker 5 caused by the change (decrease) in the rotation speed of the sensor unit rotary blade 41. When the image signal is output to the sensor circuit 10 upon detection, the sensor circuit 10 converts the image signal into an electric signal and sends out an alarm.

[0034]

As described above, according to the present invention, the second blade is installed on the air blowing side of the fan for generating the air flow by the rotation of the first blade and is rotated by the air flow discharged from the fan. By providing a blade and a sensor unit that detects a change in the number of revolutions of the second blade and issues an alarm, and mounted on a lower portion of the unit to be cooled to cool a heat generating device in the unit to be cooled. A fan unit, a dustproof filter installed on the air suction side of the fan body, and a sensor unit having the second blade mounted on the air outlet side of the fan body and rotated by an airflow discharged from the fan body. And the sensor unit further includes a sensor unit rotation shaft having one marker for detecting the number of rotations, and the second blade as the second blade. Sensor unit rotating blades, a stroboscope that emits light at a predetermined cycle toward the marker, a monitoring camera that detects marker movement, and image signals sent from the monitoring camera that detects marker movement are converted to electrical signals Further, by providing a sensor circuit that performs cooling, the sensor circuit issues an alarm indicating that the dust filter is clogged only when an image signal indicating that the marker is moving is input from the monitoring camera. At the same time as the amount of air taken in by the fan decreases, the sensor unit detects this and issues an alarm, so that the dust filter can be cleaned or replaced at the same time as the clogging occurs, and the temperature rise in the unit to be cooled occurs. It can prevent malfunction, destruction, or system failure of devices on the printed circuit board With the results.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a dustproof fan is not clogged in an embodiment of a cooling fan according to the present invention. FIG. FIG. 3B shows a state where air is being sent, and FIG. 2B shows a state where air is being smoothly blown to the sensor unit in the state shown in FIG.

FIG. 2 is a cross-sectional view showing a state in which the dust-proof fan is clogged in one embodiment of the cooling fan of the present invention;
(A) shows a state in which the specified air flow rate is not sent to the unit to be cooled even though the fan is rotating at a low speed, and (b) shows a state in which the sensor unit rotating blades are in the state shown in FIG. It is a figure showing a state where a specified number of rotations cannot be obtained.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fan main body 2 Fan rotation shaft part 3 Fan rotation blade 4 Sensor unit 5 Marker 6 Dustproof filter 7 Unit to be cooled 8 Stroboscope 9 Surveillance camera 10 Sensor circuit 41 Sensor unit rotation blade 42 Sensor unit rotation shaft A, B Air flow

Claims (4)

[Claims] 1. A second fan installed on an air blowing side of a fan for generating an air flow by rotation of a first blade and rotated by the air flow discharged from the fan.
And a sensor unit that detects a change in the rotation speed of the second blade and issues an alarm. 2. A fan main body mounted on a lower part of the unit to be cooled for cooling a heat generating device in the unit to be cooled, a dustproof filter installed on an air suction side of the fan main body, 2. The cooling fan according to claim 1, further comprising: the sensor unit having the second blade mounted on an air blowing side and rotated by an airflow discharged from the fan body. 3. 3. The sensor unit according to claim 1, further comprising:
A rotation axis of the sensor unit having a plurality of markers;
A sensor unit rotating blade as a blade, a stroboscope that emits light at a predetermined period toward the marker,
3. The monitoring camera according to claim 1, further comprising: a monitoring camera that detects the movement of the marker; and a sensor circuit that converts an image signal sent from the monitoring camera that detects the movement of the marker into an electric signal. Cooling fan. 4. The sensor circuit according to claim 3, wherein an alarm indicating that the dust filter is clogged is issued only when the image signal indicating that the marker is moving is input from the monitoring camera. The cooling fan as described.