JP2015038338A - Blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blower capable of certainly reducing noise.SOLUTION: A blower includes: an axial flow fan 40 driven to rotate for generating an air flow; and a shroud 30 formed with a suction port portion 31 of air sucked into the axial flow fan 40, and a blowoff port portion 32 for blowing out the air from the axial flow fan 40. The axial flow fan 40 has a plurality of blades 42 radially extends from a boss portion 41 provided at a rotation center and arranged separately from each other in a rotating direction, and a ring portion 43 for circumferentially connecting outer peripheral end portions of the plurality of blades 42. At least a part 34 of an inner peripheral wall surface of the blowoff port portion 32 is positioned on an inner side in a diametrical direction of the axial flow fan 40 in regard to an inner peripheral wall surface 44 of the ring portion 43.

Description

  The present invention relates to a blower provided with an axial fan.

  2. Description of the Related Art Conventionally, an air blower including an axial fan having a plurality of blades and a shroud that holds the axial fan and guides an air flow generated by the axial fan is known. In such a blower, a backflow of air from the blower outlet side to the suction port side of the axial fan occurs in the gap (tip gap) between the blade tip of the axial fan and the shroud. For this reason, there has been a problem that noise increases due to interference between the normal suction flow and the reverse flow.

  On the other hand, an air blower in which a guide member (Coanda ring) is provided on the downstream side of the air flow of the axial fan in the shroud has been proposed (see, for example, Patent Document 1). According to this, the blowing air blown out from the axial fan flows along the wall surfaces of the guide member and the shroud due to the property (Coanda effect) that the air tends to flow along the object. For this reason, the backflow of air can be reduced and noise reduction can be achieved.

Special table 2009-531599 gazette

  By the way, when the above-described guide member is not provided, the air flow flowing into the axial fan has a velocity component in the direction perpendicular to the rotation axis, so the flow of the blown air from the axial fan is contracted. It becomes. Furthermore, since the air flow velocity is faster on the radially inner side than the radially outermost peripheral portion of the axial fan, the air flow immediately after being blown out from the axial fan is likely to be contracted.

  For this reason, if the flow path cross-sectional area of the air flow path is increased from the immediately downstream side of the outlet of the axial flow fan, the air flow is easily separated from the wall surface of the shroud. When the air flow is separated from the wall surface of the shroud, the pressure in the vicinity of the wall surface increases, the front-back differential pressure at the tip portion (tip portion) of the blade increases, and the backflow of air tends to occur. For this reason, there exists a problem that the backflow reduction effect by providing the guide member described in the said patent document 1 cannot fully be acquired.

  An object of this invention is to provide the air blower which can reduce noise reliably in view of the said point.

  In order to achieve the above object, according to the first aspect of the present invention, the axial blower fan (40) that is driven to rotate to generate an airflow, and the air inlet port that is sucked into the blower fan (40) are provided. (31) and the air blower provided with the shroud (30) in which the blower outlet part (32) which blows off air from an air blower fan (40) was formed, an air blower fan (40) is a boss | hub part provided in the rotation center A plurality of blades (42) extending radially from (41) and spaced apart from each other in the rotational direction, and a ring portion (43) that circumferentially connects the outer peripheral ends of the plurality of blades (42). ), And at least a part (34) of the inner peripheral wall surface of the blowout port (32) has a diameter of the blower fan (40) with respect to the inner peripheral wall surface (44) of the ring portion (43). It is located inside the direction

  According to this, at least a part (34) of the inner peripheral wall surface of the blower outlet (32) is radially inward of the blower fan (40) with respect to the inner peripheral wall surface (44) of the ring portion (43). Therefore, the cross-sectional area of the air flow path on the downstream side of the air flow most downstream end (45) of the blower fan (40) is defined as the air flow path at the air flow most downstream end (45) of the blow fan (40). It can be smaller than the cross-sectional area. For this reason, it can suppress that the airflow which blown off from the ventilation fan (40) peels from the inner peripheral wall surface of a shroud (30). Therefore, since the air flow blown out from the blower fan (40) flows along the inner peripheral wall surface of the blowout port (32) of the shroud (30), it is possible to reliably suppress the backflow of air and thereby reliably reduce noise. It becomes possible to reduce.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

It is a top view which shows the air blower which concerns on 1st Embodiment. It is II-II sectional drawing of FIG. It is the front view which looked at the air blower concerning 1st Embodiment from the blower outlet side. It is a characteristic view which shows the relationship between the ratio of the internal diameter difference (delta) with respect to ring part internal diameter D0, a noise level, and the air volume of blowing air. It is the front view which looked at the air blower concerning 2nd Embodiment from the blower outlet side. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The air blower shown by this embodiment is comprised as an air blower used for the cooling of the refrigerant | coolant heat radiator and radiator of a motor vehicle.

  As shown in FIGS. 1 to 3, the blower device includes a refrigerant radiator 10, a radiator 20, a shroud 30, an axial fan 40, and a motor 50.

  The refrigerant radiator 10 is a heat exchanger that cools the refrigerant by exchanging heat between the refrigerant circulating in the refrigeration cycle (not shown) and the outside air. The radiator 20 is a heat exchanger that cools the engine coolant by exchanging heat between the engine coolant and the outside air. The refrigerant radiator 10 is disposed on the vehicle front side of the radiator 20, that is, on the upstream side of the air flow. The refrigerant radiator 10 and the radiator 20 are connected and integrated.

  The shroud 30 is a component that holds the motor 50 and guides the air flow so that the air flow induced by the axial fan 40 flows to the refrigerant radiator 10 and the radiator 20. The shroud 30 is disposed on the vehicle rear side of the radiator 20, that is, on the air flow downstream side.

  Further, the shroud 30 has an air inlet 31 for air sucked into the axial fan 40 and an outlet 32 for blowing air from the axial fan 40. The suction port 31 covers the back surface of the radiator 20, that is, the surface of the radiator 20 on the vehicle rear side. The air outlet 32 has a cylindrical shape that communicates with the air inlet 31 and also communicates with the outside.

  Furthermore, the planar shape of the air outlet 32 of the shroud 30 is circular. On the other hand, the planar shape of the shroud 30 is a rectangle. That is, the planar shape of the outer peripheral edge portion of the shroud 30 is rectangular. Moreover, the opening area of the suction inlet 31 is larger than the opening area of the outlet 32.

  The axial fan 40 is an axial fan that blows air, and is configured to rotate around a rotation axis. The axial fan 40 extends radially from a boss portion 41 provided at the center of rotation, and has a plurality of blades 42 that are spaced apart from each other in the rotational direction, and the outer peripheral ends of the plurality of blades 42 are circumferential. And a ring portion 43 connected to the.

  In the present embodiment, the axial fan 40 is disposed in the hollow portion of the air outlet portion 32 of the shroud 30. A clearance 61 is formed between the ring portion 43 and the inner peripheral surface of the air outlet portion 32. As a result, the axial fan 40 is rotatable in the air outlet portion 32 without contacting the air outlet portion 32.

  The motor 50 is an electric motor that gives rotational power to the axial fan 40 and has a motor shaft 51. The motor 50 is supported by a plurality of motor stays 33 provided at the air outlet 32 of the shroud 30. And the motor 50 rotates the axial fan 40 by rotating the motor shaft 51, and generates an air flow in the axial direction of the axial fan 40, ie, the axial direction of the rotating shaft. The above is the overall configuration of the blower.

  Next, the detailed shape of the outlet part 32 of the shroud 30 will be described. As shown in FIG. 2, the inner peripheral wall surface 34 at the end of the air outlet 32 on the downstream side in the air flow direction (opposite to the suction port 31) is axially flowed relative to the inner peripheral wall 44 of the ring portion 43. It is located inside the fan 40 in the radial direction.

  Specifically, a projecting portion 35 that projects inward in the radial direction is provided at the downstream end of the air outlet 32 in the air flow direction. The inner peripheral wall surface 34 of the projecting portion 35 is formed in a substantially arc shape whose cross section viewed from the direction perpendicular to the rotational axis of the axial fan 40 projects inward in the radial direction.

  When viewed from the axial direction of the rotational axis of the axial fan 40, the inner peripheral wall surface 34 of the protrusion 35 is located on the inner side in the radial direction of the axial fan 40 with respect to the inner peripheral wall surface 44 of the ring portion 43. ing. In this embodiment, the protrusion part 35 is provided over the perimeter of the edge part in the air flow direction downstream in the blower outlet part 32. As shown in FIG.

  A gap 62 is formed between the air flow upstream end of the protrusion 35 and the air flow downstream end of the ring portion 43. The gap 62 communicates with the clearance 61. For this reason, as indicated by the broken-line arrows in FIG. 2, a part of the blown air of the axial fan 40 flows into the clearance 61 from the gap 62 and is blown to the suction part (the air flow upstream side) of the axial fan 40. Backflow may occur.

  As described above, the projecting portion 35 is provided at the air outlet portion 32 of the shroud 30, and the inner peripheral wall surface 34 of the projecting portion 35 is axially flowed with respect to the inner peripheral wall surface 44 of the ring portion 43 of the axial fan 40. By positioning the inner side in the radial direction of the fan 40, the cross-sectional area of the air flow path immediately downstream of the air flow most downstream end 45 of the axial fan 40 is changed to the air flow at the air flow most downstream end 45 of the axial fan 40. It can be smaller than the road cross-sectional area. For this reason, it can suppress that the airflow blown from the axial fan 40 peels from the inner peripheral wall surface of the blower outlet part 32. FIG.

  Thereby, since the air flow blown out from the axial fan 40 flows along the inner peripheral wall surface of the blowout port 32, the pressure in the vicinity of the inner peripheral wall surface 34 of the protruding portion 35 is reduced. For this reason, since the pressure in the vicinity of the clearance 61 is also reduced, the pressure difference between the upstream side and the downstream side of the clearance 61 can be reduced. Therefore, it is possible to reliably suppress the backflow of air through the clearance 61, and it is possible to reliably reduce noise.

  Here, the inner diameter of the ring part 43 of the axial fan 40 is referred to as a ring part inner diameter D0, and the minimum inner diameter of the outlet part 32 is referred to as an outlet part minimum inner diameter D1. Further, the difference (D0−D1) between the ring portion inner diameter D0 and the blowout portion minimum inner diameter D1 is also referred to as an inner diameter difference δ. In the present embodiment, the air outlet portion minimum inner diameter D1 refers to the inner diameter of the portion of the air outlet portion 32 where the protruding portion 35 is provided.

  FIG. 4 shows the relationship between the ratio of the inner diameter difference δ to the ring inner diameter D0 and the noise level, and the ratio of the inner diameter difference δ to the ring inner diameter D0 (δ / D0) and the air volume of the blown air. The dashed-dotted line in FIG. 4 has shown the air volume of the blowing air in the air blower in which the protrusion part 35 is not provided.

  As shown in FIG. 4, when the projecting portion 35 is arranged at a position that is considerably distant from the ring portion 43 in the radial direction outside (see a portion in FIG. 4), neither the noise level nor the air volume of the blown air is affected. .

  When the protruding portion 35 is disposed radially outside the ring portion 43 and at a position close to the ring portion 43 (see b portion in FIG. 4), as described above, the air flow blown from the axial fan 40 is The protrusion 35 is attracted to the inner peripheral wall surface 34. Thereby, since the air volume of the air which flows backward through the clearance 61 decreases, the air volume of the blown air increases. However, since the air flow blown out from the axial fan 40 is a contracted flow, the air flow is separated from the inner peripheral wall surface of the shroud 30, and the noise level does not decrease.

  On the other hand, if the blower outlet minimum inner diameter D1 is made too small (refer to part f in FIG. 4), the ventilation resistance is increased by the protrusion 35, and the air volume of the blown air is reduced. Specifically, when δ / D0 exceeds 20%, the air volume of the blown air is reduced as compared with the case where the protruding portion 35 is not provided. Therefore, it is desirable to set the ring portion inner diameter D0 and the outlet portion minimum inner diameter D1 so as to satisfy the relationship 0 <δ / DO ≦ 0.20, that is, 0 <(D0−D1) /DO≦0.20. (See parts c to e in FIG. 4).

  Further, by setting the ring portion inner diameter D0 and the outlet portion minimum inner diameter D1 to satisfy the relationship of 0 <δ / DO ≦ 0.10, that is, 0 <(D0−D1) /DO≦0.10 ( The increase in ventilation resistance due to the projections 35 and the portions c and d in FIG. 4 is reduced, and the air volume of the blown air can be 90% or more of the maximum air volume.

  Furthermore, by setting the ring portion inner diameter D0 and the outlet portion minimum inner diameter D1 so as to satisfy the relationship of 0 <δ / DO ≦ 0.05, that is, 0 <(D0−D1) /DO≦0.05 ( 4), the increase in ventilation resistance due to the protrusion 35 is almost eliminated, and the reduction in the air volume of the blown air is completely eliminated.

(Second Embodiment)
Next, 2nd Embodiment of this invention is described based on FIGS. The second embodiment is different from the first embodiment in that the blower outlet minimum inner diameter D1 is changed in the circumferential direction of the rotating shaft of the axial fan 40.

  First, the distance in the radial direction of the rotating shaft from the inner peripheral wall surface 36 of the outlet 32 to the outer peripheral edge 37 of the shroud 30 when viewed from the axial direction of the rotating shaft of the axial fan 40 is defined as the outer peripheral distance. The planar shape of the shroud 30, that is, the shape of the surface perpendicular to the rotational axis of the axial fan 40 is such that the air outlet portion 32 is circular and the outer peripheral edge portion 37 is rectangular. Accordingly, the outer peripheral distance is not constant in the circumferential direction of the rotation shaft of the axial fan 40 and changes. In other words, the outer peripheral distance is different depending on the rotation angle of the axial fan 40.

  Of the air flow blown from the axial fan 40, the air flow blown from a portion having a long outer peripheral distance is likely to be peeled off from the inner peripheral wall surface of the shroud 30. In the present embodiment, the blower outlet portion minimum inner diameter D1 is formed so as to change in the entire circumference in the circumferential direction of the rotating shaft of the axial fan 40.

  More specifically, the blower outlet minimum inner diameter D1 is formed so as to be smaller as a portion where air flow is easily separated from the inner peripheral wall surface of the shroud 30. In other words, the blower outlet minimum inner diameter D1 is formed to be small at a position where the outer peripheral distance is long.

  In the present embodiment, as shown in FIG. 5, in the circumferential direction of the rotation shaft of the axial fan 40, the range in which the blower outlet minimum inner diameter D <b> 1 is reduced corresponds to the portion of the shroud 30 that has the longest outer circumferential distance. The air outlet 32 is vertically symmetrical about the position of the outlet 32. That is, the range where the blower outlet minimum inner diameter D1 is made small is the length from the position of the blower outlet 32 corresponding to the portion of the shroud 30 where the outer peripheral distance is the longest to the rotation upstream side of the axial fan 40 and the rotation downstream. The length to the side is the same.

  More specifically, when the shroud 30 is divided into four regions by two diagonal lines (broken lines in FIG. 5) in the planar shape of the shroud 30, two regions including the portion of the shroud 30 having the longest outer peripheral distance ( 5) is a range in which the blowout port minimum inner diameter D1 is reduced. On the other hand, the other two regions, that is, the two regions including the portion of the shroud 30 where the outer peripheral distance is the shortest (see the B portion in FIG. 5) are the ranges in which the blower outlet minimum inner diameter D1 is increased.

  In the protrusion 35 corresponding to the portion of the shroud 30 where the outer peripheral distance is shortened, that is, in the range where the blower outlet minimum inner diameter D1 is increased, the blower outlet minimum inner diameter D1 is equal to the ring inner diameter D0. . Moreover, in this embodiment, as shown in FIG. 5, in the blower outlet part 32, between the site | part with a large blower outlet minimum internal diameter D1 and the site | part with a small blower outlet minimum internal diameter D1 changes in steps.

  As described above, the portion of the air outlet portion 32 of the shroud 30 where the air flow from the inner peripheral wall surface of the shroud 30 is liable to be separated, that is, the portion of the air outlet portion where the outer peripheral distance is long is reduced. Therefore, it is possible to suppress the separation of the air flow from the inner peripheral wall surface of the shroud 30 at the portion. Thereby, the backflow of the air through the clearance 61 is reliably suppressed, and as a result, the noise can be reliably reduced.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows without departing from the spirit of the present invention.

  (1) The shape of the protrusion part 35 of the blower outlet part 32 shown by said each embodiment is an example. Of course, the height (the length in the radial direction of the rotating shaft of the axial fan 40) and the width (the length in the axial direction of the rotating shaft of the axial fan 40) of the protrusion 35 are also appropriately determined according to the shape of the shroud 30. You only have to set it.

  (2) In the second embodiment, the example in which the portion between the portion where the blower outlet minimum inner diameter D1 is large and the portion where the blower outlet minimum inner diameter D1 is small is changed stepwise in the blower outlet 32. Not only this but the site | part with a large blower outlet minimum internal diameter D1 and the site | part with a small blower outlet minimum internal diameter D1 in the blower outlet part 32 may be continuous.

30 Shroud 31 Suction port 32 Air outlet 40 Axial fan (fan)
41 Boss part 42 Blade 43 Ring part

Claims (4)

An axial blower fan (40) that is rotationally driven to generate an airflow;
A blower device comprising an air inlet port (31) sucked into the blower fan (40) and a shroud (30) formed with an outlet port (32) for blowing air from the blower fan (40). Because
The blower fan (40)
A plurality of blades (42) extending radially from a boss portion (41) provided at the center of rotation and spaced apart from each other in the rotational direction;
A ring portion (43) that circumferentially connects the outer peripheral ends of the plurality of blades (42);
At least a part (34) of the inner peripheral wall surface of the blowout port portion (32) is located on the inner side in the radial direction of the blower fan (40) with respect to the inner peripheral wall surface (44) of the ring portion (43). The air blower characterized by performing. The ring portion inner diameter which is the inner diameter of the ring portion (43) is D0,
When the air outlet portion minimum inner diameter, which is the minimum inner diameter of the air outlet portion (32), is D1,
2. The blower according to claim 1, wherein the inner diameter of the ring part and the minimum inner diameter of the outlet part are set so as to satisfy a relationship of 0 <(D 0 −D 1) /DO≦0.20.   The blower according to claim 2, wherein the inner diameter of the ring part and the minimum inner diameter of the outlet part are set so as to satisfy a relationship of 0 <(D0−D1) /DO≦0.10.   The blower according to claim 2, wherein the ring portion inner diameter and the blowout port minimum inner diameter are set so as to satisfy a relationship of 0 <(D0−D1) /DO≦0.05.

Images