JP2005201198A - Axial fan with backflow preventive mechanism and cooling structure of unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an axial fan with a backflow preventive mechanism capable of automatically exercising a backflow preventive mechanism at the time of stopping owing to a defect and the like. <P>SOLUTION: In the axial fan 15 for blowing air in a direction E by rotating and driving an impeller 3 equipped with a plurality of blades 3a around a blade supporting boss 3b by a motor 2 in a direction C, respective blades 3a can be attached to the blade supporting boss 3b at variable angles.The respective blades 3a are rotatably attached so that angles can be varied for the blade supporting boss 3b by a shaft 6 and relation between the respective blades 3a and the shaft 6 is set to generate moment for rotating the blades 3a in a direction of an angle at the time of blowing air by receiving air pressure due to rotation at the time (a) of driving rotation of the impeller 3 and is set to generate moment for rotating the blades 3a in a direction of an angle at the time of blocking by receiving air pressure in a direction G which is opposite to a direction E of blowing air in a state that the impeller 3 is not being driven. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an axial fan with a backflow prevention mechanism for cooling used in electronic equipment and the like, and a cooling structure for a unit including the axial fan.

  With rapid computerization in recent years, when an electronic device such as a computer is used in a company or the like, it is frequently operated continuously for 24 hours from the viewpoint of customer service work. Accordingly, if the electronic device becomes uncontrollable due to a failure or the like, the customer is greatly inconvenienced, and the demand for improving the reliability of the electronic device has further increased.

  In response to such demands, manufacturers that provide electronic devices usually respond by providing redundancy to the main unit. That is, the manufacturer responds by designing so that even if one of the accessory units mounted on the electronic device breaks down, the electronic device can be always operated without being out of control. Therefore, the fan that cools the accessory unit mounted on the electronic device is not limited to this example. Even if one fan fails, it can be cooled by the remaining fans. I am doing so.

  FIGS. 4A and 4B show a cooling structure of the HDD (Hard Disk Drive) mounting device 20 as an example, where FIG. 4A is a top view and FIG. 4B is a rear view. The arrow in the figure (a) has shown the flow of air. In this example, a plurality of HDDs 22 as cooling bodies are disposed adjacent to each other in a rectangular cylindrical chassis 21. Two axial fans 14 are mounted side by side on the opposite side of the HDD 22. The cooling structure of the HDD mounting apparatus 20 is a system in which the air in the chassis 21 is drawn by the fan 14 to suck the air from the gap between the adjacent HDDs 22 and cool the HDD 22. Further, although the HDD cooling capacity of the HDD mounting apparatus 20 is considered so that one fan 14 is possible, another fan 14 is provided for redundancy in the event of a failure. In this example, the number of the fans 14 is two, but may be three or more in a mountable range.

  The fan 14 includes an impeller 13 in which a blade support boss (not shown) and the blade 13a are integrated, a motor (not shown) that rotationally drives the impeller 13, and a frame (not shown). The blades 13 a are inclined so as to generate a blowing force by the rotation of the impeller 13, and are disposed with a predetermined gap 12. Due to the rotation of the impeller 13, the wind generated by the blades 13 a flows through the gap 12.

  By the way, when one of the fans 14 of the HDD mounting device 20 fails and the rotation stops (the right side in FIG. 4B is stopped), not only the gap between the HDDs 22 but also the blade 13a of the fan 14 on the stop side. Inflow of air also starts from the gap 12, and there is a problem that the cooling efficiency of the HDD 22 that is the original purpose is lowered.

  Therefore, conventionally, in order to compensate for this, as shown by the dotted line in the figure, a shutter 23 is provided on the exhaust side of the fan 14 (see, for example, Patent Document 1 and Patent Document 2).

  In addition, although not intended to prevent backflow, in order to adjust the air blowing performance, there is a type in which the blade inclination angle (= blade pitch) is variable and the blade inclination can be adjusted with a knob (for example, And Patent Document 3).

JP-A-6-111559 JP-A-4-371745 JP-A-2-55900

  As described above, when one of the two fans 14 stops due to a failure, a shutter 23 is provided separately from the fan 23 to prevent backflow from the stop-side fan 14. However, in that case (the same applies to Patent Documents 1 and 2), there is a problem that the structure becomes complicated by the provision of the shutter 23 and the cost is increased. Further, depending on the structure of the shutter 23, a space having a dimension indicated by F in the drawing is required on the rear surface of the apparatus, and there is a possibility that other ranges, such as even a cable, cannot be deployed.

  In addition, when the blade angle of the impeller is made variable as in the technique of Patent Document 3, a slight backflow prevention effect is expected by adjusting the blade angle so that the gap between the blades is as small as possible. Although it may be possible, since the purpose of the technique of Patent Document 3 is not the backflow prevention at the time of failure stop but the performance adjustment, it cannot be expected that an effective backflow prevention effect can be expected. Moreover, since it is necessary to adjust the angle of the blades by manually operating the knob, it can be said that it cannot be expected at all as a countermeasure against a failure.

  In consideration of the above circumstances, the present invention does not incur an extra cost as in the case of providing a shutter, does not take up extra space, and does not require any special operation. It is an object of the present invention to provide an axial fan with a backflow prevention mechanism capable of exhibiting a backflow prevention function and a cooling structure for a unit including the axial fan.

  In order to achieve the above object, an invention according to claim 1 is directed to an axial fan that blows air in a fixed direction by rotating an impeller having a plurality of blades around a blade support boss in a fixed direction by a motor. The blades are displaced with respect to the blade support bosses at the time of blowing when the blades are driven and rotated, and the blades receive air resistance due to the rotation to increase the gap between the blades. When the wind pressure in the direction opposite to the direction is received, the angle is variable so that the wind pressure is displaced to the shielding angle that minimizes the gap between the blades.

  According to a second aspect of the present invention, the blade according to the first aspect is attached to the blade supporting boss so as to be rotatable between the blade angle and the shielding angle so as to be variable between the blade angle and the blade angle. When the impeller is driven and rotated, the moment of rotating the blade in the direction of the air blowing angle is generated when the impeller is driven to rotate, and the impeller is rotated in the direction opposite to the air blowing direction when the impeller is not driven. When the wind pressure is received, the relationship is set so as to generate a moment for rotating the blade in the shielding angle direction.

  According to a third aspect of the present invention, there is provided a unit cooling structure in which a plurality of axial fans with a backflow prevention mechanism according to the first or second aspect are arranged in parallel in a unit box.

  According to the first aspect of the present invention, the blades of the impeller are attached to the blade support boss so that the angle is variable, and when the impeller is driven to rotate, the blades receive air resistance due to the rotation, and the gap between the blades automatically. The blade is automatically shielded to minimize the gap between the blades due to the wind pressure when the blade is displaced to the angle at the time of blowing, and when the blade is subjected to wind pressure in the direction opposite to the blowing direction when the impeller is not driven. Since it is displaced at an hour angle, it can perform the same air blowing function as a general axial fan during normal rotation, and when it stops due to a failure etc. Can be blocked by.

  In addition, the structure for preventing the backflow is merely a little ingenuity for the attachment of each blade, and since no separate shutter is provided, no extra cost is required as in the case of providing a shutter, and there is no extra cost. No space. In addition, since each blade is automatically displaced to the air blowing angle and the shielding angle by air resistance and wind pressure, no special operation is required, and the backflow prevention function can be exhibited automatically when stopped due to a failure or the like. . Therefore, it is possible to provide a device with high satisfaction for the user at low cost.

  Further, by attaching the blades at variable angles as in the second aspect of the invention, the backflow prevention function can be easily demonstrated, and by incorporating a plurality of units in the unit as in the third aspect of the invention, A decrease in cooling performance can be suppressed.

  Hereinafter, an axial fan with a backflow prevention mechanism according to an embodiment of the present invention (hereinafter, simply referred to as “axial fan” or “fan”) will be described with reference to the drawings.

  1A and 1B are cross-sectional views of an axial flow fan 15 according to the embodiment, in which FIG. 1A shows a state during blowing, and FIG. 1B shows a state during shielding that exhibits a backflow prevention function. FIG. 2 is a front view of the axial fan 15 in the state of shielding.

  As shown in FIG. 1, the axial fan 15 includes a frame body 1, a motor 2, and an impeller 3. As shown in FIG. 2, the motor 2 is arranged at the center of the frame 1 via a connecting rod 11, and an impeller 3 is attached to a rotation shaft (not shown) of the motor 2. The impeller 3 includes a plurality of blades 3a and blade support bosses 3b. The blades 3a are arranged at regular intervals around the blade support boss 3b and are attached to the blade support boss 3b so that the inclination angle is variable, as will be described later. Therefore, in this case, unlike the prior art, the blade 3a and the blade boss 3b are not configured as an integrally molded product. The impeller 3 is attached to a rotation shaft (not shown) of the motor 2 by a blade support boss 3b, and is driven to rotate in the direction of arrow C (constant direction) by the motor 2, so that the direction of arrow E (constant direction). To blow.

Next, how each blade 3a is attached to the blade support boss 3b will be described.
The blade 3a is attached to the blade support boss 3b so that the angle is variable. When the impeller 3 is driven to rotate, the air resistance caused by the rotation in the direction of the arrow C is reduced as shown in FIG. When receiving the pressure of the wind G in the direction opposite to the blowing direction in the non-driven state of the impeller 3, the air receiving wall 3 e is displaced to an angle at the time of blowing that increases the gap 12 between the blades 3 a. As shown in FIG. 1 (b), the wind pressure is used to displace the shield 12 at a shielding angle that minimizes the gap 12 between the blades 3a.

  That is, as shown in FIG. 2, each blade 3a is fitted in the hole 7 formed in the cylindrical peripheral wall 3c of the blade support boss 3b with the shaft 6 projecting from the inner peripheral end so that the radial direction of the blade support boss 3b. Is supported rotatably about an axis along the axis. A flange 8 for preventing the shaft 6 from coming off is provided at the tip of the shaft 6 penetrating through the hole 7, and a locking rod 9 projects from the outer periphery of the flange 8. On the other hand, inside the blade support boss 3b, there are two stoppers 10 for positioning the blade 3a at the blowing angle shown in FIG. 1 (a) and the shielding angle shown in FIG. Projected. Accordingly, the blade 3 a can be freely rotated within the range in which the locking rod 9 hits the two stoppers 10 by the restriction of the stopper 10.

  As described above, the vane 3a is provided with the wind receiving wall 3e at the front end edge in the rotation direction. The wind receiving wall 3e receives air resistance due to rotation when the impeller 3 is driven to rotate in the direction of the arrow C, regardless of the position of the blade 3a. It is formed to generate a rotating moment.

  Further, the positional relationship between the blade 3a and the shaft 6 is such that when the impeller 3 receives the pressure of the wind G in the direction opposite to the blowing direction when the impeller 3 is not driven, the blade 3a is in any angular position. It is set to give a moment to rotate in the direction of the angle at the time of shielding. That is, the dimension B from the shaft 6 to the rear end in the rotation direction of the blade 3a is set to be larger than the dimension A from the shaft 6 to the front end in the rotation direction of the blade 3a. When the wind pressure is received, the blade 3a is rotated on the shielding side.

Next, the operation will be described.
When the motor 2 of the axial fan 15 is energized, the impeller 3 starts to rotate in the direction of arrow C. At this time, since the wind receiving wall 4 of the blade 3 is directed in a direction to receive air resistance, the blade 3a rotates about the shaft 6 in the direction of the arrow D due to this resistance, and finally in FIG. It is held at the air blowing angle shown. And the impeller 3 will continue to rotate in that state. This state is the same as the rotation state of a general axial fan, and the axial fan 15 exhibits a blowing function in the direction of arrow E.

  On the other hand, when the rotation of the impeller 3 is stopped for some reason, each blade 3 a can be freely rotated about the shaft 6. Therefore, if no external force is applied, the rotational position may remain misaligned. However, when air flows in the direction G opposite to the blowing direction E of the fan 15, the wind receiving range of the blades 3 is set to A <B, so the wind pressure received in the range B exceeds the wind pressure received in the range A. Thus, the blade 3a rotates in the direction opposite to the arrow D and is held at a position (blocking position) that closes the gap 12 that is the ventilation path, as shown in FIG. For this reason, most of the air flow in the reverse direction G can be blocked.

FIG. 3 is a plan view (a) and a rear view (b) of a cooling structure of a unit in which two axial flow fans 15 are arranged in parallel.
The arrows in FIG. 3 indicate the air flow. A plurality of HDDs 22 as cooling bodies are arranged adjacent to each other in a rectangular cylindrical chassis 21. Two axial fans 15 of the above embodiment are attached to the opposite side of the HDD 22. The cooling structure of the device 20 is a system in which the air in the chassis 21 is drawn by the fan 15 to suck the air from the gap between the HDDs 22 and cool the HDD 22. Further, the cooling capacity of the HDD 22 by the fan 15 is considered so that one fan 15 is possible, and another fan 15 is provided for redundancy in the event of a failure. Here, when one fan 15 is stopped due to a failure, reverse inflow of air starts from the gap 12 between the blades 3a of the stopped fan 15. However, all of the air flows due to the pressure on the plate surface of the blade 3a due to the backflow. The blade 3a rotates to the angle at the time of shielding and is held at a position closing the gap 12, so that most of the reverse flow is blocked and kept in that state.

  Thus, when the blade 3a of the impeller 3 is driven and rotated, the blade 3a is displaced to the air blowing angle [angle of FIG. 1 (a)] that automatically receives the air resistance due to the rotation and automatically enlarges the gap 12 between the blades 3a. When the impeller 3 receives a wind pressure in the direction G opposite to the blowing direction when the impeller 3 is not driven, the vane 3a is automatically shielded by the wind pressure to minimize the gap between the vanes 3a [FIG. The angle of (b)] is displaced, so that the same function as a general axial fan can be exhibited during normal rotation. Further, when the device itself is stopped due to a failure or the like, the reverse inflow of air can be reliably blocked.

  In addition, the structure for realizing the backflow prevention only needs to be slightly devised for the attachment of each blade 3a, that is, the angle can be varied within a predetermined range by the shaft 6, the stopper 10, etc., and a separate shutter is provided. Therefore, there is no extra cost as in the case of providing a conventional shutter, and no extra space is required.

  In addition, each blade 3a is automatically displaced by the air resistance and wind pressure due to its shape and the positional relationship of the shaft 6, so that no special operation is required at all. The backflow prevention function can be exhibited automatically at the time of stoppage due to failure or the like. Therefore, a highly satisfactory device can be provided to the user.

It is sectional drawing of the axial-flow fan of embodiment of this invention, (a) is the state at the time of ventilation, (b) has shown the state at the time of shielding which exhibits a backflow prevention function. It is a front view of the axial-flow fan of the said embodiment in the state at the time of shielding. It is the top view (a) and rear view (b) of the cooling structure of the unit which has arranged the two axial flow fans of the embodiment in parallel. It is the top view (a) and rear view (b) of the cooling structure of the unit which arranged two conventional axial fans in parallel.

Explanation of symbols

2 motor 3 impeller 3a blade 3b blade support boss 6 shaft 10 stopper 12 gap 15 axial flow fan with backflow prevention mechanism

Claims (3)

In an axial fan that blows air in a fixed direction by rotating an impeller having a plurality of blades around a blade support boss in a fixed direction by a motor,
When the impeller is driven to rotate, each blade is displaced to a blowing angle that receives air resistance due to the rotation and enlarges a gap between the blades, and in the non-driven state of the impeller, An axial fan with a backflow prevention mechanism, which is mounted with a variable angle so as to be displaced to a shielding angle that minimizes the gap between the blades when the wind pressure is received in the reverse direction. The axial flow fan with a backflow prevention mechanism according to claim 1.
Each blade is rotatably attached to the blade support boss by an axis so that the angle between the blowing angle and the shielding angle is variable, and the relationship between each blade and the shaft is determined by driving the impeller. Sometimes, when a wind pressure in the direction opposite to the blowing direction is received in a non-driven state of the impeller when the impeller is subjected to air resistance due to rotation, a moment is generated to rotate the blade in the direction of the blowing angle. An axial fan with a backflow prevention mechanism, characterized in that it is set in a relationship that generates a moment to rotate in the direction of. A cooling structure for a unit, wherein a plurality of axial fans with a backflow prevention mechanism according to claim 1 or 2 are arranged in parallel in a unit box.

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