JP6448524B2 - Counter-rotating blower - Google Patents

Description

  The present invention relates to a counter-rotating blower in which an upstream impeller and a downstream impeller rotate in different directions.

  As an axial-flow type blower, one in which an upstream impeller and a downstream impeller are arranged with the rotation axis center aligned in the axial flow direction is known. Compared with a rotating single impeller, such a counter-rotating blower cancels counter torque, because the flow of wind concentrates in the axial flow direction due to the rectification effect, and the air volume to the cooling target increases. There are advantages such as being able to. By utilizing the advantage, it is possible to reduce the size, power consumption, and silence of the blower.

  Further, as the counter-rotating blower, one used as an air cooling device provided inside a case of an electric device is well known. In that case, normally, the upstream impeller and the downstream impeller are arranged inside the duct. That is, it has a closed structure to obtain a static pressure (Patent Documents 1 and 2). In contrast, the inventor of the present application has an open structure that sucks air from between an upstream impeller and a downstream impeller in order to improve the performance of a blower that blows air from the outside of the personal computer as a peripheral device of the personal computer. The heavy inversion type blower was proposed (patent documents 3 to 5).

  Among these counter-rotating blowers, the one disclosed in Patent Document 5 includes an upstream first impeller arranged downstream of the center of the rotating shaft in the axial direction and a downstream side as described in the claims. A first motor that rotates the first impeller, a second motor that rotates the second impeller, and a guard that surrounds the first impeller and the second impeller. In the counter-rotating blower in which one impeller and the second impeller rotate in different directions, the rotational speed of the first impeller is X, the rotational speed of the second impeller is Y, and the diameter of the first impeller is When L1, the diameter of the second impeller is L2, the number of blades of the first impeller is A, and the number of blades of the second impeller is B, the first motor and the second motor are When the first motor and the second motor are driven at the same voltage as the same type of motor with the same rack, they are configured such that the relationship X> Y, L1 <L2, A <B is satisfied. It is a counter-rotating blower.

  The counter-rotating blower described in Patent Document 5 includes a first impeller and a second impeller when the first motor and the second motor are motors of the same type having common specifications, and the first motor and the second motor are driven with equal voltages. The two-impeller structure was devised as follows and completed.

  That is, the first motor and the second motor need only have the rotational speed and torque during driving within the allowable range of the appropriate load. As conditions, if the area of the blade acting on the air increases, the torque increases and the rotational speed decreases. That is, as the impeller diameter increases, the rotational speed decreases. As the number of blades increases, the rotational speed decreases. Further, when the width of the impeller blade with respect to the axial flow direction is increased, the rotational speed is decreased.

  Here, in consideration of increasing the air volume by sucking air from the open structure, that is, between the first impeller and the second impeller, the diameter L2 of the second impeller is set larger than the diameter L1 of the first impeller. did. In consideration of the air flow and the like, considering that the diameter L2 of the second impeller is larger than the diameter L1 of the first impeller, the number B of blades of the second impeller is larger than the number A of blades of the first impeller. Set. Then, the rotational speed X of the first impeller is relatively larger than the rotational speed Y of the second impeller. According to such a structure, it becomes possible to raise the ventilation efficiency of a counter rotating type blower.

  Further, under the condition that the rotational speed X of the first impeller is larger than the rotational speed Y of the second impeller, the blade width W1 of the first impeller in the axial flow direction is made larger than the blade width W2 of the second impeller. Largely set. That is, this is a device for increasing the diameter L2 of the second impeller. According to such a configuration, air can be more actively sucked from between the first impeller and the second impeller. And it becomes a structurally balanced design, and ventilation efficiency improves.

  The inventor of the present application has completed the invention described in Patent Document 5 by repeating trial manufacture and verification in order to obtain an excellent open structure counter rotating fan, and that this configuration is extremely effective. It has also been confirmed by comparative experiments with prototypes with different conditions.

Japanese Patent No. 3993118 Japanese Patent No. 4128194 Japanese Patent No. 5709921 Japanese Patent No. 5726107 Japanese Patent No. 5749195

  Based on the knowledge obtained from the trial production and verification of the invention as described above, the inventor of the present application uses two motors that are used as a power source for this type of counter-rotating blower with the same action. The present invention has been completed by examining a structure capable of producing an effect or an effect similar to that.

  In addition, as a counter-rotating blower using one motor, one that drives each impeller using a gear train may be considered, but this is not preferable from the viewpoint of cost increase and noise generation, and so on. Was excluded from design and development.

  Therefore, the present invention has an object to obtain a counter-rotating blower having a simpler configuration and high energy efficiency without using the above gear train while using one motor.

When the invention described in the first claim of the present application is described with the reference numerals used in the embodiments, the first impeller (110) on the upstream side and the downstream side of the first impeller (110) arranged with the rotation axis center aligned in the axial direction. A counter-rotating blower (1) comprising a second impeller (120), wherein the first impeller (110) and the second impeller (120) rotate in different directions,
One of the first impeller (110) and the second impeller (120) is rotationally driven by a motor, and the other impeller is rotatably provided on the rotating shaft, and When one impeller rotates, it is a non-motor-driven one that rotates in the direction opposite to the rotation direction of the one impeller by the wind power of the one impeller,
The counter-rotating blower (1) sucks air from the rear in the axial flow direction and sucks air from between the first impeller (110) and the second impeller (120),
Furthermore,
a: The diameter of the one impeller is L1, the diameter of the other impeller is L2,
b: The blade number of the one impeller is A, the blade number of the other impeller is B,
c: When the one impeller and the other impeller are viewed from the front in the axial direction, the ratio of the gap between the impellers to the total impeller area of the one impeller is P, and the total impeller of the other impeller The ratio of the gap between each impeller to the area is Q,
These are counter-rotating blowers characterized in that the relations L1 <L2, A <B, and P> Q are established.

  The invention described in claim 2 of the present application is characterized in that, in claim 1, the other impeller has a straight blade section or a blade section having a different shape at the hub position and the blade tip. It is a counter-rotating blower.

  The present invention has a structure of a counter rotating fan having two impellers on the upstream side and the downstream side, one of the impellers is driven by a motor, and the other impeller rotates by receiving the wind of the one impeller. As shown in FIG. 1, wind that causes airflow loss, that is, wind that is generated by the rotation of the impeller (wind that only rotates around the impeller) and wind that is blown in the direction of the centrifugal force (lateral direction) Therefore, the air can be taken in by the rotation of the other impeller, and as a result, the blowing efficiency of the air blown from the other impeller in the axial direction can be improved.

  Further, the rectifying effect produced by the other impeller is further improved by having a straight blade cross-section portion or a blade cross-section portion having a different shape at the hub position and the blade tip on the other impeller. Is something that can be done.

It is explanatory drawing which shows the rectification | straightening effect by the downstream side impeller (2nd impeller) in this invention. 1 is a front view of a counter-rotating blower according to an embodiment of the present invention. 1 is a side view of a counter-rotating blower according to an embodiment of the present invention. 1 is a side sectional view of a counter-rotating blower according to an embodiment of the present invention. It is explanatory drawing of a 1st impeller according to the Example of this invention, (a) is a front view, (b) is a side view, (c) is a rear view. It is explanatory drawing of a 2nd impeller according to the Example of this invention, (a) is a front view, (b) is a side view, (c) is a rear view. It is explanatory drawing of the 1st impeller and the 2nd impeller concerning the Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings (FIGS. 2 to 7).

  The counter-rotating blower 1 of this example is a small blower that is driven by using a USB of a personal computer as a power source. This counter-rotating blower 1 includes an upstream first impeller 110 and a downstream second impeller 120 that are arranged with the rotation axis center aligned in the axial direction, a motor 210 that rotates the first impeller 110, and A guard 300 that surrounds the first impeller 110 and the second impeller 120 is provided, and the first impeller 110 and the second impeller 120 rotate in different directions.

  The guard 300 is a lattice-like or net-like cover, and the counter-rotating blower 1 of this example has an open structure in which air is also sucked from between the first impeller 110 and the second impeller 120. In addition, the black arrow in FIG. 3 has shown the flow of air. 5 indicates the rotational direction of the first impeller 110, and the white arrow in FIG. 6 indicates the rotational direction of the second impeller 120.

The first motor 210 is a DC motor, and uses a DC power source of 5 [V] using USB as a power source. Each impeller 110, 120 is directly connected to a hub 110a linked to a drive shaft of the motor 210 and a hub 120a linked to a shaft not using the motor. The hubs 110a and 120a of the impellers 110 and 120 are set to have the same diameter. In FIG. 4, reference numeral 220 denotes a case. This case 220 uses the motor case of the motor (second motor) of the previous invention (Patent Document 5) in this embodiment. In this example, the case 220 is provided with the second impeller 120. Free rotation is provided. That is, the second impeller 120 is non-motor driven. However, the second impeller 120 may be rotatably provided on the hub 120a without using the case 220.

  The motor 210 and the guard 300 are mounted on a support 20 that is supported with respect to the pedestal 10 so that the angle can be adjusted. A switch 30 for switching ON / OFF of the motor 210 is provided at an important point of the support 20 or the base 10. In addition to the ON / OFF function, the switch 30 can adjust the air volume by changing the voltage. The rotation speed in the following description is a value when driving at the maximum voltage.

  According to the inventor's knowledge, the counter-rotating blower is superior in terms of its blowing efficiency when the rotational speed of the impeller that rotates the motor is larger than the rotational speed of the impeller that rotates freely. Therefore, as a structure for obtaining such air blowing efficiency, the rotational speed decreases as the impeller diameter increases, the rotational speed decreases as the number of blades increases, and the impeller blade width in the axial flow direction. In consideration of the fact that the rotational speed decreases as the air pressure increases, and that the air volume is increased by sucking air from between the first impeller and the second impeller, the diameter L2 of the second impeller is reduced. It was set larger than the diameter L1.

  Further, considering the air flow and the like, considering that the diameter L2 of the second impeller is larger than the diameter L1 of the first impeller, the number B of blades of the second impeller is larger than the number A of blades of the first impeller. Set. Then, the rotational speed X of the first impeller is relatively larger than the rotational speed Y of the second impeller.

  Further, under the condition that the rotational speed X of the first impeller is larger than the rotational speed Y of the second impeller, the blade width W1 of the first impeller in the axial flow direction is made larger than the blade width W2 of the second impeller. Largely set. This is a device for increasing the diameter L2 of the second impeller, and it is possible to inhale air more actively between the first impeller and the second impeller, and the structural balance is achieved. The design has been improved, and the knowledge that the ventilation efficiency is improved has been obtained.

  According to the above configuration, the following structure has been devised in consideration of the point that the blowing efficiency of the counter-rotating blower can be increased.

  In the counter-rotating blower 1 of this example, the diameter of the first impeller 110 is L1, the diameter of the second impeller 120 is L2, the number of blades 111 of the first impeller 110 is A, and the blades 121 of the second impeller 120 are When the number is B, the width of the blade 111 of the first impeller 110 in the axial flow direction is W1, and the width of the blade 121 of the second impeller 120 is W2, they are L1 <L2, A <B, W1> W2. The relationship is established. In the case of this example, the rotation speed of the first impeller 110 is 2400 [rpm].

  The diameter L1 of the first impeller 110 is 80 [mm], and the diameter L2 of the second impeller 120 is 85 [mm]. A desirable relationship between L1 and L2 is L2 / L1 = 1.06-1.20. A practical value of L1 is 80 to 100 [mm], and a practical value of L2 is 85 to 120 [mm].

  Further, when the first impeller 110 and the second impeller 120 are viewed from the front in the axial direction, the ratio of the gap between the impellers to the total impeller area of the first impeller 110 is P, and the impeller of the second impeller 120 is It was found that P> Q, where Q is the ratio of the voids between the impellers to the total area.

  The number A of blades 111 of the first impeller 110 is five, and the number B of blades 121 of the second impeller 120 is seven. A practical number of A is 3 to 6, and a desirable number of B is 1 to 4 more than A.

  The width W1 of the blade 111 of the first impeller 110 with respect to the axial flow direction is 21 [mm], and the width W2 of the blade 121 of the second impeller 120 is 18 [mm]. A desirable relationship between W1 and W2 is W1 / W2 = 1.16 to 1.40.

  The gap G between the blade 111 of the first impeller 110 and the blade 121 of the second impeller 120 is 14.5 [mm]. A practical value of G is 1.0 to 16.5 [mm], and a more desirable value is 1.0 [mm], which should be as close as possible.

  Furthermore, in the case of this example, the second impeller 120 may have a straight blade cross-section portion or a blade cross-section portion having a different shape at the hub position and the blade tip. It has been found that the shape is suitable for turning and has a rectifying effect as a blower.

  In other words, the impeller usually has a portion where the air is rotated to push air (a surface in contact with the air) with a straight blade cross section, and the back surface has an arcuate blade cross section. In this example, the second impeller It is proposed to have a blade section 120 having a different shape at the hub position and the blade tip in addition to the section of the straight blade section. The different blade cross sections preferably include a portion of the hub 120a of the second impeller 120 having a straight blade cross section and a portion having an arcuate blade cross section at the blade tip. With this arrangement, at the blade tip having a straight blade section, it is possible to receive wind from the first impeller 110 and convert it into energy for rotating the second impeller 120, and the straight blade section. In the part of the hub 120a having this part, the wind can be blown in the axial flow direction.

  According to such a configuration of the present example, it is possible to obtain an extremely excellent counter-rotating blower that is excellent in manufacturability and has low noise and high air blowing performance.

  Furthermore, according to the knowledge of the inventor, the counter-rotating blower of the present invention has not only the configuration including the first impeller 110 that rotates the motor and the second impeller 120 that rotates freely in this example, but also the rotation and free rotation of the motor. It has been found that substantially the same effect can be obtained by setting the rotation reverse, that is, by rotating the first impeller 110 freely and rotating the second impeller 120 by the motor. In this case, the numerical values related to the blades of the first impeller 110 and the second impeller 120 of this example described above are set in reverse.

  As described above, this example is extremely rationally configured as an open structure counter-rotating fan. In addition, it is needless to say that the configuration of each part in the present example can be appropriately changed in design within the technical scope described in the claims, and is not limited to that illustrated in the drawings.

  The counter-rotating blower of the present invention can be suitably used as a small blower that is driven using a USB of a personal computer as a power source.

DESCRIPTION OF SYMBOLS 1 Counter rotating fan 10 Base 20 Support body 30 Switch 110 1st impeller 110a Hub 111 Blade 120 2nd impeller 120a Hub 121 Blade 210 Motor 220 Case 300 Guard L1 Diameter of the first impeller L2 Diameter of the second impeller W1 Axial flow Blade width W2 of the first impeller with respect to the direction Width G of the blade of the second impeller with respect to the axial flow direction Distance between the blade of the first impeller and the blade of the second impeller

Claims (2)

A first impeller (110) on the upstream side and a second impeller (120) on the downstream side that are arranged so that the rotation axis centers are aligned in the axial direction, the first impeller (110) and the second impeller (120). Are counter-rotating blowers (1) that rotate in different directions,
One of the first impeller (110) and the second impeller (120) is rotationally driven by a motor, and the other impeller is rotatably provided on the rotating shaft, and When one impeller rotates, it is a non-motor-driven one that rotates in the direction opposite to the rotation direction of the one impeller by the wind power of the one impeller,
The counter-rotating blower (1) sucks air from the rear in the axial flow direction and sucks air from between the first impeller (110) and the second impeller (120),
Furthermore,
a: The diameter of the one impeller is L1, the diameter of the other impeller is L2,
b: The blade number of the one impeller is A, the blade number of the other impeller is B,
c: When the one impeller and the other impeller are viewed from the front in the axial direction, the ratio of the gap between the impellers to the total impeller area of the one impeller is P, and the total impeller of the other impeller The ratio of the gap between each impeller to the area is Q,
, They are provided so that the relationship of L1 <L2, A <B, and P> Q is established.
2. The counter-rotating blower according to claim 1, wherein the other impeller has a straight blade cross-section portion or a blade cross-section portion having a different shape at a hub position and a blade tip.

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