JP4947170B2 - Operation control method for cooling fan unit - Google Patents

Description

This invention relates to an operation control method of the cooling fan units, particularly, the back wiring board (BWB) to be placed in a communication apparatus comprising a plurality of electronic circuit board mounted the operation control of the cooling fan units Regarding the method.

  A conventional electronic unit cooling structure is described in Patent Document 1 below. According to Patent Document 1, a cooling fan is mounted on an electronic unit configured by combining a high heat-generating communication device such as an electronic exchange, and a cooling system is configured by forming a forced ventilation structure inside. It was. In this cooling system, fins are attached to a highly heat-generating communication device for the purpose of reducing the heat dissipation of the electronic unit and reducing the size and weight of the device. I was trying to do it.

FIG. 19 is a side view showing a schematic configuration of a communication apparatus employing a conventional cooling system.
The cooling system of the communication device 1 is one in which axial fans are arranged on the cold air intake side and the exhaust side, respectively, and is generally called a push-pull system. The fan unit 100 constituted by the two axial flow fans 101 and 102 is provided for sucking cold air into the interior from the lower suction port 110 of the communication device 1. The exhaust fan unit 200 discharges heat to the outside from an exhaust port 210 formed in the upper part of the communication device 1, and includes two axial flow fans 201 and 202.

  An electronic circuit board (not shown) that is a target of the cooling system is a plug-in unit (PIU) inserted from the front of the communication device 1, and a plurality of sheets are arranged in the left-right direction between the two fan units 100 and 200. Mounted vertically. In FIG. 19, the insertion direction of the electronic circuit board is shown by an arrow A on the left side.

  In the conventional cooling system, the four axial fans 101, 102, 201, 202 function as a push-pull system by always operating, and radiate heat from the communication device 1 to the outside. Therefore, in the communication apparatus 1 described above, a space for inserting the two fan units 100 and 200 and a shielding plate 111 for taking air into the suction fan unit 100 from the suction port 110 at the lower front are arranged. Spaces for disposing a shielding plate 211 for exhausting air from the exhaust fan unit 200 to the exhaust port 210 are necessary in the upper rear portion of the communication device.

JP-A-5-259673

  As described above, in the push-pull cooling system configured by the axial flow type fan, both the intake direction of the cold air indicated by the arrow B and the exhaust direction indicated by the arrow C in FIG. As for the size of the electronic circuit board, not only the thickness of the axial fan of each fan unit 100, 200 but also the space for the suction port 110 and the exhaust port 210 is extra in the width of the electronic circuit board. Further, in the conventional communication device 1, when the plug-in unit of the electronic circuit board is horizontally mounted in the vertical direction, there is a problem that intake and exhaust are not performed smoothly when a plurality of communication devices are mounted in a rack. It was.

And in the cooling fan unit arrange | positioned in a communication apparatus, cooling efficiency is inadequate and the reduction in power consumption of a cooling system was not attained.
The purpose of this invention has a high cooling efficiency, it is to provide a compact, operation control method of weight reduction is possible cooling fan unit.

In order to solve the above-mentioned problem, a cooling fan unit that cools the inside of the housing by mounting a blower type fan constituting the exhaust fan unit on the housing containing the electronic circuit board is shown below. An operation control method is provided.

  The cooling fan unit is a blower type that activates only the intake fan unit that takes in cold air into the housing for a short period of time immediately after the cooling fan unit starts operation, and after a predetermined pressure difference occurs inside and outside the housing. While starting the fan, the starting torque of the blower fan is temporarily increased so that the rotational speed reaches a steady value early after the start of the blower fan.

  In order to solve the above problem, the cooling fan unit activates only the intake fan unit that takes in cool air into the housing for a short time immediately after the start of the operation of the cooling fan unit. The blower fan is started after the rotational speed is stabilized, and the starting torque of the blower fan is temporarily increased so that the rotational speed reaches a steady value early after the start of the blower fan.

According to the cooling fan units of the operation control method of this invention, in various environments, in accordance with the operating conditions of the fan, precisely because it possible to control the operation of the fan efficiency and a communication device be cooled In addition, the power consumption of the cooling system can be reduced.

It is a schematic plan view which shows the communication apparatus provided with the cooling system of the push pull structure by a blower type fan and an axial flow type fan. It is a perspective view which shows the external appearance of a communication apparatus. It is a figure which shows the wind speed vector distribution in an internal space at the time of making the rotation speed of each blower type fan correspond. It is a figure which shows adjustment of the wind speed vector by a baffle plate. It is a figure which shows the suction vector at the time of a stop of an axial flow type fan. It is a perspective view which shows the external appearance of the fan unit provided with three blower type fans. It is a side view of a fan unit showing an exhaust direction vector of each blower type fan. It is a figure which shows the wind speed vector distribution at the time of varying the rotation speed of a blower type fan. It is a top sectional view showing an insertion / extraction mechanism of a blower type fan. It is side surface sectional drawing which shows the fan unit before fitting of a plug-in connector. It is side surface sectional drawing which shows the fan unit of the state which the plug-in connector fitted. It is a block diagram explaining the function of a boost circuit. It is a figure which shows the mode of the rotation speed change of a blower type fan at the time of providing a boost circuit. It is a block diagram which shows an example of a boost circuit. It is a flowchart which shows the rotation control procedure of an axial flow type fan and a blower type fan. It is a figure which shows the sequence control circuit which drives a blower type fan and an axial flow type fan. It is a figure which shows a temperature sequence. It is a table | surface which shows the rotation speed of the blower type fan for every mode, and an axial flow type fan. It is a side view which shows schematic structure of the communication apparatus which employ | adopted the conventional cooling system.

Embodiments of the present invention will be described below with reference to the drawings.
First, the present invention will be described with respect to a communication device in which a plug-in unit is horizontally mounted.

FIG. 1 is a schematic plan view showing a communication apparatus including a cooling system having a push-pull configuration including a blower fan and an axial flow fan.
The cooling system of the communication apparatus 1 is different from the conventional cooling system in that the blower fan unit 10 includes three blower fans 11, 12, and 13. However, a fan unit 20 including an axial flow fan 21 is used on the cold air intake side. The fan unit 20 is disposed on the right side of the back side of the communication device 1, and the fan unit 10 including the blower type fans 11, 12, and 13 is inserted into the left side of the communication device 1 from the back side.

  The electronic circuit board that is the target of the cooling system is shown as a plug-in unit 30 that is inserted into the internal space 70 of the communication device 1 from the direction of the arrow A, and a plurality of electronic circuit boards are mounted horizontally in the housing 7. It is. The communication device 1 includes an air duct 61 that communicates with the suction port 73, and cool air indicated by an air flow vector B is introduced from the fan unit 20 into the air duct 61 and the internal space 70 of the housing 7. The internal space 70 of the housing 7 is a region where the electronic circuit board is stored when the plug-in unit 30 is inserted into the communication device 1, and the air duct 61 is adjacent to the internal space 70 of the housing 7. Is formed. By providing the rectifying plate 2 in the vicinity of the fan unit 20 of the air duct 61, the air flow introduced into the housing 7 is divided as will be described later. Further, a rectifying plate 3 different from the rectifying plate 2 is provided at a position away from the fan unit 20 of the air duct 61.

  The communication device 1 is provided with a back wiring board (BWB) 4 for wiring a power supply line or the like fixed near the back surface of the internal space 70. The BWB 4 is used to horizontally mount a plurality of electronic circuit boards with a predetermined interval, and a part of the BWB 4 is deleted to take in air to the fan unit 20. The communication device 1 is configured to cover the back surface with a cover 5, and the cover 5 is attached to the housing 7 so as to be freely opened and closed by a rotating shaft 51. A space 40 for wiring is formed between the cover 5 and the back side of the BWB 4.

  Further, the cooling air introduced into the housing 7 from the suction port 73 on the back surface passes between the respective electronic circuit boards, and is sent from the air duct 61 to the blower fans 11, 12, 13 of the fan unit 10. Is sucked sideways. The fan unit 10 is configured to be inserted into the air duct 62 on the left side of the front surface of the housing 7 from the back side and be detachable. The fan unit 10 is in the air duct 62 and has a predetermined gap with the internal space 70. Arranged to form G. Details of the insertion / extraction structure of the fan unit 10 will be described later.

  In FIG. 1, the magnitudes of the wind speed vectors corresponding to the blower fans 11, 12, and 13 are indicated by arrows D1, D2, and D3. The magnitudes of the wind speed vectors D1, D2, and D3 are proportional to the amount of air sucked by the blower fans 11, 12, and 13 in the fan unit 10. The direction of the wind velocity vectors D1, D2, and D3 sucked by the fan unit 10 is perpendicular to the air flow vector B introduced from the axial flow fan 21 into the air duct 61. Further, the blower type fans 11, 12, 13 of the fan unit 10 exhaust the heat inside the communication device 1 in the direction indicated by the air flow vector C from an exhaust port 74 formed on the left side of the front surface of the communication device 1. To function.

  Each electronic circuit board is formed with a rectifying plate 30P at a predetermined position for restricting the flow of cooling air passing between them. In addition, on the left and right sides of the rear surface of the casing 7, metal fixtures 71 and 72 for fixing the communication device 1 in a rack are fixed by screws or the like.

FIG. 2 is a perspective view showing an appearance of the communication device.
Electronic circuit boards 31 to 36 constituting six stages of plug-in units are inserted into the communication device 1 from the front surface thereof. Here, heat generated in the electronic circuit boards 31 to 36 is discharged from the exhaust port 74 provided on the left side of the front surface of the housing 7 by the three blower fans 11, 12, and 13, respectively.

  As described above, in the embodiment described above, the blower type fans 11, 12, and 13 are combined with the axial flow type fan 21 to constitute a push-pull type cooling system, which corresponds to the shielding plates 111 and 211 in the conventional device. It is possible to eliminate a useless space in the vertical direction of the communication device 1 that performs the processing. Further, by providing the rectifying plates 2 and 3 and the air duct 61, the suction flow rate of the cold air in the fan unit 20 can be made to flow uniformly in the internal space 70 and with a constant air volume. It is possible to reliably prevent the temperature from rising.

However, when operating continuously controlled such cooling systems, Oite the fan control circuit, it is known that the following problem arises. That is, as will be described later, the fan control circuit has a function of monitoring the rotation speed of the fan in order to determine the deterioration of the fan motor, and outputting an alarm when the rotation speed falls below the minimum rotation speed. At startup, it is necessary to mask so that unnecessary alarm signals are not generated. This masking time is conventionally set to about 1.5 sec, which is sufficient for the axial flow fan 21, but for the blower fans 11, 12, 13 until the motor rotation is stabilized. Therefore, the fan control circuit is prepared separately from the axial flow type fan 21 so that the alarm mask time is lengthened and no alarm is output at the time of activation.

FIG. 3 is a diagram showing the wind speed vector distribution in the internal space when the rotation speeds of the blower fans are made to coincide. FIG. 4 is a diagram showing adjustment of the wind speed vector by the current plate.
As in the conventional push-pull cooling system (FIG. 19), the push-side fan unit 100 and the pull-side fan unit 200 are controlled to operate at different rotational speeds. It was. However, in a fan unit composed of a plurality of fan motors, such as the fan unit 10, all the fan motors are always controlled to operate at the same rotational value.

  Here, as shown in FIG. 3, when the fan unit 10 including the three blower fans 11, 12, 13 is operated at the same rotational value, the wind speed at the blower fan 13 close to the exhaust port 74. The vector D3 becomes the largest, followed by the wind speed vector D2 at the intermediate blower fan 12, and the smallest becomes the wind speed vector D1 of the blower fan 11 farthest from the exhaust port 74.

  Such a magnitude relationship between the wind speed vectors D1, D2, and D3 indicates that there is a non-uniform air volume inside the housing 7, and is generated by the plug-in unit 30 mounted horizontally. It may be difficult to reliably discharge heat to the outside, which may cause a local temperature increase inside the communication device 1. Therefore, as shown in FIG. 4, the rectifying plate 2 is provided at the above-described position of the air duct 61 communicating with the suction port 73 so that the air flow introduced into the housing 7 is divided. Here, assuming that the opening area on the suction side of the fan unit 20 is 100, the current plate is such that the area opened to the internal space 70 of the housing 7 is 85 and the area for diverting to the air duct 61 is 15. 2 was placed. Thereby, even if the rotation speeds of the three blower fans 11, 12, 13 are the same, the wind speed vectors D1, D2, D3 can be adjusted to the same magnitude. This has been confirmed experimentally.

FIG. 5 is a diagram showing a suction vector when the axial flow type fan is stopped.
FIG. 5 shows that when the axial flow fan 21 is stopped, cold air flows into the communication device 1 from the suction port 73 through the gap between the blades of the axial flow fan 21. Normally, the axial fan 21 is not always operated, and only the blower fans 11, 12, and 13 are operated, so that the inside of the communication device 1 is heated to a temperature higher than a predetermined temperature or the blower fan is replaced. Only when the fan unit 10 is removed, such as when, is it controlled to operate temporarily. Therefore, if the fan unit 20 is configured by the axial flow type fan 21, the cold air can be sucked from the suction port 73 even when the fan unit 20 is stopped.

  In other words, even when the axial flow fan 21 is not in operation, since the intake is performed through the propeller gap of the axial flow fan 21, there is an advantage that a new intake port other than the intake port 73 is not required. When the temperature at which the axial flow fan 21 is operating rises, the same suction port 73 is used as the suction port.

Next, the cooling fan unit of the present invention will be described by taking the fan unit 10 in the communication device 1 described above as an example.
FIG. 6 is a perspective view showing an external appearance of a fan unit including three blower fans. FIG. 7 is a side view of the fan unit showing an exhaust direction vector of each blower type fan.

As shown in these drawings, the configuration of the fan unit 10 communicating with the exhaust port 74 of the communication device 1 is such that three blower fans 11, 12, and 13 are arranged in a staggered manner.
Now, let us consider a case where the plug-in unit 30 that is horizontally mounted in the communication device 1 accommodates an electronic circuit board 31 that is inserted in the lower stage of the internal space 70 and that has a higher power consumption. As shown in FIG. 1, a gap G is provided between the plug-in unit 30 and the fan unit 10 that are horizontally mounted in the housing 7. Then, by arranging the three blower fans 11, 12, and 13 in a staggered arrangement, the cool air flowing into the housing 7 is concentrated on the lower electronic circuit boards 31 and 32 and efficiently cooled. It becomes possible. Further, such a fan unit 10 can easily realize space saving in the vertical direction of the communication device 1.

  As shown in FIG. 7, the exhaust direction of the blower type fans 12 and 13 is assembled so as to be the same as the direction of the exhaust port 74 through which the fan unit 10 communicates, but only the exhaust direction of the blower type fan 11 is The fan unit 10 is disposed perpendicular to the exhaust direction. This is an arrangement for saving space in the vertical direction of the fan unit 10, and an exhaust duct 11 a is provided at the exhaust port of the blower type fan 10, and the exhaust direction communicates with the fan unit 10. It is directed to the mouth 74.

  As described above, when the communication device 1 is maintained at a constant temperature by the plurality of blower fans 11, 12, and 13, the cooling target is concentrated by arranging them in a staggered manner rather than arranging them on the same line. In addition to being able to cool, the blower type fans 11, 12, 13 in the fan unit 10 can be arranged efficiently.

Figure 8 is a diagram showing a wind velocity vector distribution in a case having different rotational speed of the blower fan.
The fan unit 10 of FIG. 8 is operating the blower type fans 11, 12, and 13 at rotation speeds R1, R2, and R3 (R1>R2> R3), respectively. In this case, the wind speed vectors D1, D2, and D3 of the three blower fans 11, 12, and 13 can be made equal without providing the rectifying plate 2 as shown in FIG. Therefore, by controlling the operation of the blower type fans 11, 12, and 13 in the fan unit 10 at different rotational speeds, the inside of the housing 7 can be more easily cooled with a uniform air flow than the communication device of FIG. Can be cooled with.

FIG. 9 is a plan sectional view showing a blower fan insertion / extraction mechanism.
As described above, the fan unit 10 is inserted into the air duct 62 on the left side of the housing 7 from the rear surface of the communication device 1, and stores the three blower fans 11, 12, and 13. 14 and a control circuit board 15 disposed on a plane facing the BWB 4 in parallel at the rearmost end of the fan unit housing 14. A plug-in connector 16 that transmits and receives an external signal is provided at a predetermined position of the control circuit board 15, and the operation of the blower type fan is controlled based on the external signal. Here, since the control circuit board 15 is arranged so as to be parallel to the BWB 4, when the fan unit 10 is inserted into the housing 7 to a predetermined position, the plug-in connector 16 automatically becomes the connector 41 on the BWB 4 side. Mates with.

  That is, an electronic circuit board (not shown) cooled by the fan unit 10 is inserted from the front side of the BWB 4 and is electrically connected by the BWB 4. Since the connector 41 is disposed on the back side of the BWB 4 at a position where it can be fitted to the plug-in connector 16, the fan unit housing 14 is moved in the direction of arrow H until the rear end face coincides with the device fixing bracket 71. By inserting, each becomes a fitting state and electrical connection is obtained. Further, since the control circuit board 15 and the BWB 4 are arranged in parallel to each other, a large control circuit board 15 can be used according to the area of the BWB 4, and thus the degree of freedom regarding the position where the connector is installed can be increased. There are advantages.

  FIG. 10 is a side sectional view showing the fan unit before the plug-in connector is fitted. In this figure, only the rear end portion of the fan unit housing 14 is shown along the line XX in FIG.

  The fan unit 10 includes a float plate 17 that slidably holds the control circuit board 15. The float plate 17 is formed with round holes 17h of a predetermined size near its four corners, and bolts 18a and 18b fixed to the round holes 17h and the fan unit housing 14 via spacers (not shown). By these, it hold | maintains so that a slide is possible within the plane parallel to BWB4. In addition, guide pins 42 and 43 having a small diameter at the tip are implanted in the BWB 4, and guide holes 17 g are formed at positions corresponding to the guide pins 42 and 43 of the float plate 17.

  As shown in a partially enlarged view in FIG. 10, the guide hole 17g has a size corresponding to the diameter of the guide pin 43. Therefore, the fan unit housing 14 is moved in the direction of arrow H in the figure to communicate with the communication device. At first, the float plate 17 is freely slid in the direction of arrow J, and finally the plug-in connector 16 on the control circuit board 15 side is connected to the connector 41 on the BWB 4 side. Can be aligned.

FIG. 11 is a side sectional view showing the fan unit in a state in which the plug-in connector is fitted.
When the plug-in connector 16 is fitted to the connector 41 of the BWB 4, the float plate 17 to which the control circuit board 15 is fixed is positioned by the two guide pins 42 and 43. The float plate 17 has play with respect to the fan unit housing 14 due to the spacer between the round hole 17h and the bolts 18a and 18b, so that the assembly error of the communication device 1 and the assembly error of the fan unit housing 14 are increased. At the same time, the guide pins 43 are inserted into the guide holes 17g of the float plate 17 so that the connector 41 is aligned. As a result, the labor of connector connection when the fan unit 10 is mounted is reduced, and at the same time, problems such as pin bending of the connector pins of the plug-in connector 16 are prevented.

Next, the operation control method for the cooling fan unit of the present invention will be described by taking the fan unit 10 for cooling the communication device 1 as an example.
FIG. 12 is a block diagram illustrating the function of the boost circuit.

  In the figure, a positive power source 142 and a negative power source 143 supply power to the blower fan motor 10M, the rotation speed control circuit 151, and the boost circuit 152, respectively. Here, the rotational speed control circuit 151 controls the rotational speed of the blower fan motor 10M to be constant. Further, a boost signal is introduced from the boost circuit 152 to the rotation speed control circuit 151.

  When the cooling of the communication device 1 is started by the fan unit 10, it is preferable that the alarm mask time described above coincides with that of the axial flow fan. Therefore, in the fan unit 10, the boost circuit 152 is turned on only for several hundreds of milliseconds immediately after power feeding, so that a higher voltage than during normal operation is supplied to the blower type fan motor 10M only during the on time, and in a short time. It is designed to increase to a stable rotational speed.

FIG. 13 is a diagram illustrating how the rotational speed of the blower fan changes when the boost circuit is provided. Here, the horizontal axis represents time, and the vertical axis represents the rotational speed.
t0 is an operation start time, and t1 is an elapsed time of an alarm mask time in a normal axial fan. In the axial flow type fan, the rotational speed of the fan reaches r2 and stabilizes at time t2, but the blower type fan does not reach the specified rotational speed r0 (minimum guaranteed rotational speed) at time t1, At time t3, the rotational speed r2 is gradually stabilized. Therefore, by turning on the boost circuit 152 shown in FIG. 12 until time t2, it is possible to shorten the time until the rotational speed of the blower fan is stabilized. After time t2 when the rotational speed r2 reaches a stable value, the boost circuit 152 is turned off to supply a normal power supply voltage to the blower type fan. As a result, the alarm mask time in the blower fan can be set in the same manner as in the axial fan.

FIG. 14 is a block diagram illustrating an example of a boost circuit.
In the boost circuit 152, a series circuit of resistors R1 and R2, a series circuit of a resistor R4 and a transistor Q1, and a series circuit of a transistor Q2 and a resistor R5 are connected between a positive power source 142 and a negative power source 143. ing. The transistor Q1 has a base connected to a connection point between the resistors R1 and R2, and capacitors C1 to C3 and a resistor R3. Further, the transistor Q2 has a base connected to a connection point between the resistor R4 and the transistor Q1, and outputs a boost signal from the emitter via the diode D11.

  Using the boost circuit 152 described above, the starting torque of the blower fan can be temporarily increased for a short time immediately after the start of the operation of the cooling fan unit. Therefore, when the blower type fan is mounted in the housing containing the electronic circuit board, the rotation speed reaches a steady value early after the start of the blower type fan. The time required to reach the specified rotational speed r0 and the time required for the rotational speed to stabilize become shorter. Therefore, the cooling fan unit that cools the communication device has many achievements so far compared to the blower type fan that conventionally required a long start-up time by introducing a very simple and inexpensive boost circuit. Since almost the same control circuit as that of a certain axial flow type fan can be used, the apparatus can be reduced in size and cost.

FIG. 15 is a flowchart showing a rotation control procedure of the axial fan and the blower fan.
In the cooling system in which the exhaust fan unit 10 is configured by the blower type fans 11, 12, and 13 like the communication device 1 shown in FIG. 1, the short time after the cooling system is started is kept in the housing 7. Only the intake fan unit 20 that takes in cold air is activated, and the blower type fans 11, 12, and 13 are activated after a predetermined pressure difference is generated inside and outside the casing 7, thereby using the boost circuit described above. Similarly, after the blower fan is started, the time for the rotation speed to reach a steady value can be shortened.

  In FIG. 15, at step ST1, the main power is turned on. Thereafter, in step ST2, power is supplied only to the axial flow fan, and in step ST3, the axial flow fan motor is first rotated.

  At that time, since the blower fan is not rotating, only the cool air is sent into the housing 7 of the communication device 1 and no exhaust is performed. Therefore, about 1.5 seconds after the axial flow fan reaches a stable rotational speed, the pressure in the housing 7 is somewhat higher than the external pressure (step ST4). In such a state, power is supplied to the blower type fan (step ST5) and the blower type fan motor is rotated (step ST6), so that the blower type fan is accelerated by the internal and external pressure difference of the housing 7. Since the mechanical boost function works, the blower fan motor reaches the specified rotational speed in a short time.

  Next, a method of switching the operation mode according to the device environment such as the ambient temperature of the communication device and the operation status of each fan after the operation of the fan unit constituting the cooling system is stabilized will be described.

FIG. 16 is a diagram showing a sequence control circuit for driving the blower fan and the axial flow fan.
In FIG. 16, a positive power source 142 and a negative power source 143 supply power to the axial fan motor 20M via the blower fan motor 10M, the rotation speed control circuit 151, and the switch circuit 20S, respectively. The blower type fan motor 10M is connected to a rotational speed detection circuit 153, and is connected to a rotational speed comparison circuit 155 together with a specified rotational speed circuit 154 so as to monitor its operating condition.

  The comparison circuit 156 is connected to a threshold circuit 157 that outputs a temperature T2, and monitors the temperature of the temperature sensor 44 that detects the ambient temperature of the communication device 1. That is, when the ambient temperature is higher than the temperature T2, the blower fan is operated at a high rotational speed r2, and when the ambient temperature is lower than the temperature T1 (= T2-ΔT), the rotational speed is operated so as to operate at a low rotational speed r1. An instruction is given to the control circuit 151.

  The switch circuit 20S is connected to a comparison circuit 158 and a rotation speed comparison circuit 155 to control on / off of the axial fan motor 20M. Among these, the comparator circuit 158 is connected to a threshold circuit 159 that outputs a temperature T4 and monitors the temperature of the temperature sensor 44 that detects the ambient temperature of the communication device 1. That is, when the ambient temperature is higher than the temperature T4, the axial fan is operated at a predetermined rotational speed r3. When the ambient temperature is lower than the temperature T3 (= T4-ΔT), the operation of the axial fan is stopped. Thus, the switch circuit 20S is switched. Here, ΔT is a temperature hysteresis with respect to the temperature sensor 44 and is normally set to about 5 ° C.

FIG. 17 is a diagram showing a temperature sequence. In this figure, the horizontal axis represents the ambient temperature of the communication device, and the vertical axis represents the rotation speed of each fan constituting the fan unit.
As shown in FIG. 1, the cooling fan unit includes an axial fan 21 that takes in cool air into the housing 7 of the communication device 1 that houses the electronic circuit board, and a blower type that exhausts the air taken into the housing 7. When configured with the fans 11, 12, and 13, it is necessary to cool the communication device 1 according to the ambient temperature of the communication device 1. In other words, in a normally air-conditioned environment (temperature T2 ° C. or lower), in the state shown in FIG. 5 described above, only the blower fan motor rotates at a low speed (rotation speed r1) and the axial fan motor stops. Can be in a state.

However, when the air conditioning management is not normal (temperature T2 ° C. or higher), the blower type fan motor must be controlled to rotate at high speed.
Furthermore, not only is the air conditioning management not normal, but also when the temperature exceeds a predetermined temperature (temperature T4 ° C.), the blower fan motor continues to rotate at a high speed, while the axial flow fan motor also rotates at a predetermined speed (rotation speed r3 ) To control rotation.

  By the way, when the blower type fan motor fails and stops, or when the rotation speed is reduced to the minimum rotation speed r0 or less, the axial flow type fan motor is set to a predetermined value regardless of the ambient temperature of the communication device 1. It is necessary to control the inside of the housing 7 to be cooled by rotating at the speed (the number of rotations r3).

FIG. 18 is a table showing the rotation speeds of the blower fan and the axial flow fan for each mode.
This table shows the rotation speed of each fan assuming four operation modes as an operation control method of the cooling fan unit in an emergency. The first to third modes (FAIL1 to FAIL3) are exhaust fan units equipped with three blower fans 11, 12, and 13, and one of the blower fan motors stops or the number of rotations thereof is low. This is the case when it is below the minimum rotation speed. In these modes, the axial fan 21 is controlled to rotate at a predetermined speed (rotation speed r3), and at the same time, a predetermined alarm is notified to the administrator, and the blower fan is replaced. I am doing so.

  During such replacement work, the communication device 1 is not equipped with a blower fan. In the table, as the operation mode (REMOVE) at that time, the axial flow type fan 21 is controlled to rotate at a predetermined speed (rotation speed r3). Note that the duration of this stop state is limited to 3 minutes here.

  (Supplementary Note 1) In a communication device including a plurality of electronic circuit boards mounted on a back wiring board (BWB), a casing that integrally stores the electronic circuit boards, and the electronic circuit boards are cooled in the casings. An air intake fan unit for taking in air, and an air exhaust fan unit for exhausting air taken in the housing by a blower type fan arranged in a direction in which the air intake direction is substantially 90 degrees with respect to the exhaust direction. A communication device characterized by that.

  (Supplementary note 2) The communication device according to supplementary note 1, wherein the exhaust fan unit is configured by a plurality of blower fans having a suction direction orthogonal to an air flow vector taken into the casing.

  (Additional remark 3) The said housing | casing is equipped with the air duct for flowing the air from the said air intake fan unit, and the baffle plate arrange | positioned in this air duct, and each blower type fan of the said exhaust fan unit respectively The communication apparatus according to appendix 2, wherein a uniform flow rate of air is discharged from the inside of the casing.

(Supplementary note 4) The communication device according to supplementary note 1, wherein the intake fan unit is an axial flow fan.
(Supplementary Note 5) The intake fan unit includes a cooling air intake hole that is open even when not in operation, and operates the blower fan of the exhaust fan unit to draw cold air into the housing. The communication apparatus according to supplementary note 1, wherein

  (Additional remark 6) It was set as the structure which distribute | distributes the flow volume of the cooling air in the said housing | casing optimally, when the some blower type fan which comprises the said exhaust fan unit operate | moves at a respectively different rotation speed. The communication apparatus according to appendix 1.

  (Supplementary Note 7) When the blower fans are operated at different rotational speeds, the flow rate of the cooling air in the casing is distributed in proportion to the amount of heat generated from the electronic circuit board. The communication device described.

  (Supplementary Note 8) In a cooling fan unit that cools a plurality of electronic circuit boards that are electrically connected by a BWB, a fan unit housing that houses a blower-type fan, and the BWB of the fan unit housing that faces the BWB A control circuit board arranged parallel to the BWB at a position to control the operation of the blower fan, and a connector provided on the BWB when the fan unit housing is mounted at a cooling position of the electronic circuit board; A cooling fan unit comprising: a plug-in connector disposed at a predetermined position of the control circuit board so as to be fitted.

(Supplementary note 9) The cooling fan unit according to supplementary note 8, wherein a plurality of blower fans are staggered in the fan unit casing.
(Supplementary Note 10) The fan unit housing includes a float plate that slidably holds the control circuit board. When the fan unit housing is mounted, the fan unit housing slides the float board while plugging in the control circuit board. The cooling fan unit according to appendix 8, wherein the connector is aligned with the connector on the BWB side.

  (Supplementary Note 11) A guide hole corresponding to a guide pin protruding from the BWB side is formed in the float plate, the control circuit board is positioned at a predetermined position by the guide hole, and the plug-in connector is connected to the BWB. The cooling fan unit according to appendix 10, wherein the cooling fan unit is aligned with the connector on the side.

  (Additional remark 12) In the operation control method of the cooling fan unit which mounts a blower type fan in the housing containing the electronic circuit board and cools the inside of the housing, a short time immediately after the operation of the cooling fan unit is started. The operation of the cooling fan unit is characterized in that the starting torque of the blower fan is temporarily increased by the time so that the rotational speed reaches a steady value early after the blower fan is started. Control method.

  (Supplementary Note 13) In the cooling fan unit in which the blower fan constitutes the exhaust fan unit, only the intake fan unit that is taken into the housing for a short time immediately after the start of the operation of the cooling fan unit is activated, 13. The operation control method for a cooling fan unit according to appendix 12, wherein the blower type fan is started after a predetermined pressure difference is generated inside and outside the housing.

  (Additional remark 14) It is comprised from the axial flow type fan which takes in cold air in the housing | casing which accommodated the electronic circuit board, and the blower type fan which exhausts the air taken in into the said housing | casing, and the inside of the said housing | casing according to ambient temperature In the operation control method of the cooling fan unit that performs cooling, the cooling is characterized in that in a normally air-conditioned environment, the blower type fan is rotated at a low speed and the axial flow fan is controlled to be stopped. Of fan unit operation control.

(Supplementary note 15) The operation control method for a cooling fan unit according to supplementary note 14, wherein the blower fan is controlled to rotate at high speed in an environment where air conditioning management is not normal.
(Supplementary Note 16) In an environment where air conditioning management is not normal and the temperature exceeds a predetermined temperature, the blower fan is rotated at a high speed and the axial fan is controlled to rotate at a predetermined speed. 15. A method for controlling the operation of a cooling fan unit according to appendix 14.

(Supplementary Note 17) wherein, when the blower fan is stopped, or the rotational speed thereof is equal to or less than the minimum frequency is appended and controls to rotate the axial flow fan where a constant speed 14 The operation control method of the cooling fan unit described.

  (Supplementary Note 18) When the cooling fan unit is equipped with a plurality of the blower type fans, and one or more of the blower type fans are stopped or the number of rotations is less than the minimum number of rotations. The method for controlling the operation of a cooling fan unit according to appendix 14, wherein the axial flow type fan is controlled to rotate at a predetermined speed.

  (Supplementary note 19) The cooling fan unit operation control method according to supplementary note 14, wherein when the blower fan is not mounted, the axial flow fan is controlled to rotate at a predetermined speed.

1 Communication device 2, 3, 30P Rectifying plate 4 Back wiring board (BWB)
DESCRIPTION OF SYMBOLS 5 Cover 7 Case 10 Exhaust fan unit 11, 12, 13 Blower type fan 15 Control circuit board 16 Plug-in connector 17 Float board 20 Intake fan unit 21 Axial flow type fan 30 Plug-in unit 31-36 Electronic circuit Board 41 Connector 61, 62 Air duct 70 Internal space 71, 72 Metal fitting 73 Air inlet 74 Air outlet

Claims (2)

The blower fan which constitutes an exhaust fan unit, and instrumentation wear enclosure that houses an electronic circuit board, the operation control method of the cooling fan unit for cooling the housing portion,
Only for a short period of time immediately after the start of operation of the cooling fan unit, only the intake fan unit that takes in cool air into the housing is activated, and the blower fan is turned on after a predetermined pressure difference occurs inside and outside the housing. As well as
An operation control method for a cooling fan unit, wherein the starting torque of the blower fan is temporarily increased so that the rotational speed reaches a steady value early after the blower fan is started. .   In the operation control method of the cooling fan unit that cools the inside of the housing by mounting the blower type fan constituting the exhaust fan unit on the housing containing the electronic circuit board,
  Only the intake fan unit that takes in cool air into the housing is activated for a short period of time immediately after the start of operation of the cooling fan unit, and the blower fan is activated after the number of rotations of the intake fan unit is stabilized. With
  An operation control method for a cooling fan unit, wherein the starting torque of the blower fan is temporarily increased so that the rotational speed reaches a steady value early after the blower fan is started. .

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