JP2013177832A - Contra-rotating type blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contra-rotating type blower of an open structure which is configured rationally and in which silence performance is high.SOLUTION: In a contra-rotating type blower 1, air is sucked from a rear side in axial-flow direction and air is also sucked from a gap between an upstream-side first impeller 110 and a downstream-side second impeller 120. When a blade 121 of the second impeller is watched from the front in the axial-flow direction, a distal end portion of the front edge thereof is tapered to decrease a width in a rotating direction toward a chip side. Furthermore, when a rotation radius of the blade 111 of the first impeller 110 is defined as R1, a rotation radius of a blade 121 of the second impeller 120 is defined as R2 and further a distance between a contact P and a rotation axis center O is defined as RP in the case where a tangential line is drawn from the rotation axis center O to the front edge of the blade 121 of the second impeller 120, a relation of RP<R1<R2 is established.

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, as disclosed in Patent Documents 1 to 5, a fan 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.

Japanese Patent No. 3953503 Japanese Patent No. 3959359 Japanese Patent No. 4128194 JP 2008-121440 A JP 2011-58420 A

  As the counter-rotating blower, one used as an air cooling device provided inside a personal computer 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 in order to obtain a static pressure. 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. A heavy reversing blower was proposed. And after the earnest examination, it came to the identification of a very excellent structure, and achieved this invention.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a counter-rotating blower with an open structure that is reasonably configured and has high silent performance.

  The invention described in claim 1 of the present application includes an upstream first impeller (110) and a downstream second impeller (120) arranged with the rotation axis center (O) aligned in the axial direction, and the first A first motor (210) that rotates the first impeller (110); and a second motor (220) that rotates the second impeller (120). The first impeller (110) and the second impeller (120 In the counter rotating fan (1) rotating in different directions, the counter rotating fan (1) sucks air from the rear in the axial flow direction and the first impeller (110) Air is also sucked in between the second impeller (120), and the blade (121) of the second impeller (120) has a leading edge portion when viewed from the front in the axial direction. Chip side It is towards the construction which is tapered to reduce the width of the direction of rotation counter-rotating fan (1).

  The invention described in claim 2 of the present application is the first impeller (110) on the upstream side and the second impeller (120) on the downstream side, which are arranged with the rotation axis center (O) aligned in the axial direction, A first motor (210) that rotates the first impeller (110); and a second motor (220) that rotates the second impeller (120). The first impeller (110) and the second impeller (120 In the counter rotating fan (1) rotating in different directions, the counter rotating fan (1) sucks air from the rear in the axial flow direction and the first impeller (110) Air is also sucked in between the second impeller (120), and the blade (121) of the second impeller (120) has a leading edge portion when viewed from the front in the axial direction. Chip side It has a tapered shape that decreases the width in the rotational direction, and the rotational radius of the blade (111) of the first impeller (110) is R1, and the rotational radius of the blade (121) of the second impeller (120) is R2 is the distance between the contact point (P) and the rotation axis center (O) when a tangent line is drawn from the rotation axis center (O) to the front edge of the blade (121) of the second impeller (120). When RP, they are the counter-rotating blower (1) configured such that the relationship of RP <R1 <R2 is established.

  According to the present invention, the quiet performance of the counter-rotating blower with an open structure is improved. The concept will be described below.

  The silent performance of the blower depends on the shape of the blade provided on the impeller. As a blade, a blade having a forward wing shape in which a tip portion of a leading edge is advanced in a rotation direction when viewed from the front in an axial flow direction is known. The advancing blade type blade has an advantage that it has less noise than the fan fan type blade.

  The inventor of the present application prototyped an open structure counter-rotating blower in which an impeller provided with a forward blade is disposed on the upstream side and the downstream side in the axial flow direction, and actually performed an operation experiment. The noise was found to be much louder than when each impeller was rotated independently. Therefore, we studied to reduce the noise, and after trial and error, we found that chamfering the tip of the leading edge that advanced forward in the direction of rotation of the impeller blade on the downstream side clearly reduced the noise. .

  The second impeller on the downstream side has a function of converting the turning energy of the first impeller on the upstream side into pressure in the axial flow direction. In view of its function, the front end portion of the front edge that is close to the first impeller on the upstream side and has a small angle with respect to the rotation direction is considered to be a portion having a small effect on the air from the rear. In addition, since the noise was reduced when the portion was chamfered, it was also found to be a portion that causes noise generation.

  In the present invention, the shape of the blade of the second impeller is specified in consideration of such experimental results. That is, when viewed from the front in the axial direction, the blade of the second impeller has a tapered shape in which the front end portion of the leading edge is reduced toward the tip side to reduce the width in the rotational direction.

  Further, considering that the air volume is increased by sucking air also from between the first impeller and the second impeller, the rotation radius R2 of the blade of the second impeller is the rotation of the blade of the first impeller. It was set larger than the radius R1. At this time, the distance RP between the contact point P and the rotation axis center when a tangent line is drawn from the rotation axis center O to the leading edge of the blade of the second impeller may be set smaller than the rotation radius R1 of the blade of the first impeller. . A tip from the contact P is a tapered tip portion. By setting so that the relationship of RP <R1 <R2 is established, a counter-rotating blower having high blowing efficiency and excellent quietness is obtained.

  The inventor of the present application has repeated trial manufacture and verification in order to obtain an excellent open structure counter rotating fan, and has completed the present invention. The effectiveness of the configuration of the present invention has been confirmed by comparative experiments with prototypes under different conditions.

  ADVANTAGE OF THE INVENTION According to this invention, the counter-rotating type air blower of the open structure with high quiet performance comprised rationally can be obtained.

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. It is explanatory drawing of the 2nd impeller according to the Example of this invention. It is explanatory drawing of the braid | blade of a 1st impeller and the braid | blade of a 2nd impeller according to the Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. The counter-rotating blower 1 of this example shown in FIGS. 1 to 8 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, and a first motor 210 that rotates the first impeller 110. A second motor 220 that rotates the second impeller 120, and a guard 300 that surrounds the first impeller 110 and the second impeller 120, and the first impeller 110 and the second impeller 120 rotate in different directions. It has a configuration. 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. 2 has shown the flow of air. 4 indicates the direction of rotation of the first impeller 110, and the white arrow in FIGS. 5 and 7 indicates the direction of rotation of the second impeller 120.

  The first motor 210 and the second motor 220 are the same type of DC motors with common specifications, and are wired in series with a 5 [V] DC power source using USB as a power source. Or you may wire in parallel. In any case, the circuit configuration is driven with the same voltage. Each impeller 110 and 120 has a hub 110a and 120a directly connected to a drive shaft of each motor 210 and 220, respectively. The hubs 110a and 120a of the impellers 110 and 120 are set to have the same diameter.

  The motors 210 and 220 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 first motor 210 and the second motor 220 is provided at an important point of the support 20 or the base 10. The switch 30 shown in the figure is capable of adjusting the air volume by changing the voltage in addition to ON / OFF. The rotation speed in the following description is a value when driving at the maximum voltage.

  In the counter-rotating blower 1 of this example, the rotational speed of the first impeller 110 is X, the rotational speed of the second impeller 120 is Y, the diameter of the first impeller 110 is L1, and the diameter of the second impeller 120 is L2. The number of blades 111 of the first impeller 110 is A, the number of blades 121 of the second impeller 120 is B, the width of the blade 111 of the first impeller 110 in the axial flow direction is W1, and the blade 121 of the second impeller 120 is When the width is W2, they are configured such that X> Y, L1 <L2, A <B, W1> W2 are satisfied.

  The counter-rotating blower 1 is superior in that the rotational speed of the first impeller 110 on the upstream side is larger than the rotational speed of the second impeller 120 on the downstream side in terms of the blowing efficiency. However, using the first motor 210 and the second motor 220 having different specifications in combination is not a desirable configuration from the viewpoint of cost performance in design and manufacturing.

  Therefore, in this example, the first motor 210 and the second motor 220 are the same type motors having the same specifications, and the first impeller 110 and the second impeller when the first motor 210 and the second motor 220 are driven with the same voltage. 120 structures were devised.

  The first motor 210 and the second motor 220 only need to have the rotation speed and torque during driving within the allowable range of the appropriate load, respectively. 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, the diameter L2 of the second impeller 120 was set larger than the diameter L1 of the first impeller 110 in order to increase the air volume. That is, the rotation radius R2 of the blade 121 of the second impeller 120 is set larger than the rotation radius R1 of the blade 111 of the first impeller 110. L1 = 2 × R1 and L2 = 2 × R2. The number B of the blades 121 of the second impeller 120 is set to be the number of the blades 111 of the first impeller 110 in consideration of the air flow and the like, considering that the diameter L2 of the second impeller 120 is larger than the diameter L1 of the first impeller 110. More than the number A. Then, the rotational speed X of the first impeller 110 is relatively larger than the rotational speed Y of the second impeller 120. According to such a structure, it becomes possible to raise the ventilation efficiency of a counter rotating type blower.

  Further, the width W1 of the blade 111 of the first impeller 110 in the axial flow direction is set to the blade of the second impeller 120 under the condition that the rotational speed X of the first impeller 110 is larger than the rotational speed Y of the second impeller 120. It was set to be larger than 121 width W2. That is, this is a device for making the diameter L2 of the second impeller 120 larger. According to such a configuration, air can be more actively sucked from between the first impeller 110 and the second impeller 120. The structurally balanced design improves air blowing efficiency.

  In this example, the rotation speed X of the first impeller 110 is 2400 [rpm], and the rotation speed Y of the second impeller 120 is 1400 [rpm]. A desirable relationship between X and Y is X / Y = 1.6 to 2.0. The practical value of X is 2000 to 4000 [rpm], and the practical value of Y is 1400 to 2000.

  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].

  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 12.0 to 16.5 [mm], and a more desirable value is 14.0 to 15.0 [mm].

  Next, the second impeller 120 of this example will be described. When viewed from the front in the axial flow direction, the blade 121 of the second impeller 120 has a tapered shape in which the front end portion of the leading edge decreases toward the tip side and decreases the width in the rotation direction. The second impeller 120 is obtained by designing a forward wing type impeller, and deleting the leading end portion n (see FIG. 7) of the leading edge that has advanced in the direction of rotation of the blade in order to improve the silent performance. .

  The rotation radius of the blade 111 of the first impeller 110 is R1, the rotation radius of the blade 121 of the second impeller 120 is R2, and a tangent line is drawn from the rotation axis center O to the leading edge of the blade 121 of the second impeller 120. When the distance between the contact P and the rotation axis center O is RP, they are configured such that the relationship of RP <R1 <R2 is established.

  In this example, the rotation radius R1 of the blade 111 of the first impeller 110 is 40 [mm], and the rotation radius R2 of the blade 121 of the second impeller 120 is 42.5 [mm]. The distance RP between the contact P and the rotation axis center O is 35 [mm]. A desirable relationship between R1 and R2 is R2 / R1 = 1.06 to 1.20, similar to the relationship between L1 and L2 described above. A desirable relationship between R1 and RP is R1 / RP = 1.08-1.25. The practical value of R1 is 40 to 50 [mm], and the practical value of R2 is 42.5 to 60 [mm]. At this time, a practical value of RP is 32 to 46 [mm].

  According to such a configuration, 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.

  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 type blower 10 Base 20 Support body 30 Switch 110 1st impeller 110a Hub 111 Blade 120 2nd impeller 120a Hub 121 Blade 210 1st motor 220 2nd motor 300 Guard L1 1st impeller diameter L2 2nd impeller Diameter W1 Blade width of the first impeller relative to the axial flow direction W2 Width of the blade of the second impeller relative to the axial flow direction G Distance between the blades of the first impeller and the blades of the second impeller R1 Turning radius of the blade of the first impeller R2 Rotational radius of blade of second impeller O Rotational axis center P Contact point when tangent is drawn from the rotational axis center to the leading edge of the second impeller blade RP Distance between the contact point and the rotational axis center n Leading edge of the advancing blade blade Tip of

Claims (2)

A first impeller on the upstream side and a second impeller on the downstream side arranged with the rotation axis center aligned in the axial direction, a first motor for rotating the first impeller, and a second motor for rotating the second impeller In the counter-rotating blower in which the first impeller and the second impeller rotate in different directions,
The counter-rotating blower sucks air from behind the axial flow direction, and sucks air from between the first impeller and the second impeller,
The blade of the second impeller has a tapered shape in which the front end portion of the blade of the second impeller is tapered toward the tip side when viewed from the front in the axial direction. Inverting blower. A first impeller on the upstream side and a second impeller on the downstream side arranged with the rotation axis center aligned in the axial direction, a first motor for rotating the first impeller, and a second motor for rotating the second impeller In the counter-rotating blower in which the first impeller and the second impeller rotate in different directions,
The counter-rotating blower sucks air from behind the axial flow direction, and sucks air from between the first impeller and the second impeller,
The blade of the second impeller, when viewed from the front in the axial flow direction, has a tapered shape in which the front end portion of the front edge decreases toward the tip side and decreases the width in the rotation direction.
The rotation radius of the blade of the first impeller is R1, the rotation radius of the blade of the second impeller is R2, and the contact point when a tangent line is drawn from the center of the rotation axis to the leading edge of the blade of the second impeller When the distance from the rotation axis center is RP,
The counter-rotating blower is characterized in that the relationship of RP <R1 <R2 is established.

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