JP2011190747A - Fan, molding die and fluid feeding device - Google Patents

Abstract

The present invention provides a fan that exhibits excellent air blowing capability and effectively suppresses the generation of noise, a molding die used for manufacturing the fan, and a fluid feed device including the fan.
A centrifugal fan includes a plurality of fan blades 21 arranged at intervals in the circumferential direction. The fan blade 21 has an inner edge portion 26 disposed on the inner peripheral side and an outer edge portion 27 disposed on the outer peripheral side. The fan blade 21 has a blade surface composed of a pressure surface and a suction surface. When the fan blade 21 is cut by a plane perpendicular to the rotation axis of the fan, the fan blade 21 has a blade cross section in which concave portions are formed on the pressure surface and the suction surface. The plurality of fan blades 21 include fan blades 21A to 21E having blade sections having different shapes.
[Selection] Figure 5

Description

  The present invention generally relates to a fan, a molding die, and a fluid feeder, and more specifically, a fan such as a centrifugal fan or a cross-flow fan, a molding die used for manufacturing the fan, and the fan. The present invention relates to a fluid feeder comprising:

  Regarding conventional fans, for example, in Japanese Patent Application Laid-Open No. 2008-241188, even when a resistor adheres to the upstream side of a blower, the wind speed distribution inside the unit is made uniform to suppress the surging phenomenon and the reverse suction phenomenon. On the other hand, a once-through blower aimed at reducing the occurrence of separation during inflow is disclosed (Patent Document 1). In the cross-flow blower disclosed in Patent Document 1, a plurality of first blades whose outer peripheral side thickness is thicker than the inner peripheral side, and a plurality of second blades whose inner peripheral side thickness is thicker than the outer peripheral side Are arranged side by side in the circumferential direction. When two first blades are arranged in the circumferential direction, a second blade is arranged on both sides of the first blade, and when two second blades are arranged, both sides of the second blade are arranged. The first blade is disposed in

  Japanese Laid-Open Patent Publication No. 2006-170043 discloses a cross flow fan that aims to reduce the generation of N / Z noise and to suppress the reduction of air blowing capability and the generation of noise due to fluid vibration. (Patent Document 2). In the crossflow fan disclosed in Patent Document 2, two or more kinds of blades having a fixed mounting angle and a fixed mounting pitch and different shapes are randomly arranged.

JP 2008-241188 A JP 2006-170043 A

  In recent years, in order to preserve the global environment, further energy saving is required for household electrical equipment. For example, it is known that the efficiency of an electric device such as an air conditioner (air conditioner) or an air cleaner greatly depends on the efficiency of a blower included therein. Further, by reducing the weight of the fan blade provided in the blower as a rotating object, the power consumption of the motor for rotationally driving the fan blade can be reduced, and the efficiency as the blower or the fluid feeder can be improved. Are known.

  However, the aerofoil adopted as the cross-sectional shape of the fan blade is supposed to be applied to the wing of an aircraft in the first place, and has been mainly found in the field of aeronautical engineering. For this reason, airfoil fan blades are optimized primarily in the high Reynolds number region, and are not necessarily suitable for the cross section of fan blades used in low Reynolds number regions such as home air conditioners and air purifiers. I can't say that.

  Further, when a blade shape or a double arc is adopted as the cross-sectional shape of the fan blade, the thick portion exists in a range of 30 to 50% from the front edge of the fan blade. For this reason, the weight of the fan blade is increased, which causes an increase in friction loss during rotation. However, simply reducing the weight of the fan blades may reduce the strength of the fan blades and cause cracks and other quality defects.

  Therefore, in order to improve the air blowing capacity of the fan and realize energy saving of electrical equipment such as home air conditioners and air purifiers, there is a blade cross-sectional shape suitable as a fan blade used in a low Reynolds number region. It has been demanded. Further, there is a demand for a blade cross-sectional shape that has a high lift-drag ratio, is thin and light, and has high strength.

  On the other hand, when fan blades having a single-shaped blade cross section are arranged at equal pitches (intervals), the blade tips of the fan blades pass at a constant period as the fan rotates. In this case, pressure fluctuation with a constant cycle occurs at the location where the fan blade approaches the casing that covers it, and the frequency is determined by a value obtained by multiplying the blade passing sound (nZ sound: natural number n and the number Z of fan blades). Narrow-band noise called (sound) is generated. In addition, when fan blades having a single-shaped blade cross section are arranged at an equal pitch, substantially the same air flow is formed between adjacent fan blades. In this case, turbulent noise caused by the air flow between adjacent fan blades is aligned between the plurality of fan blades, which causes narrow band noise.

  As a means for solving such a problem, it is conceivable to employ a so-called random pitch fan in which a pitch at which a plurality of fan blades are arranged is random. However, when adopting a random pitch fan, when determining the interval between adjacent fan blades, it is necessary to intentionally provide a location with a large interval and a location with a small interval apart from the optimum value based on the required air blowing performance. is there.

  In this case, at a location where the distance between adjacent fan blades is relatively large, an air flow that is opposite to the normal air flow on the blade surface is partially formed, and the air flow between adjacent fan blades is not good. There is a risk of stabilization. As a result, a low-frequency noise (abnormal noise) such as “bumpy” is generated, and there is a problem that an unpleasant discomfort is given to the user. Such abnormal noise is not so great while the fan speed is low, but increases as the fan speed increases, and eventually the entire fan casing is vibrated.

  Further, in a portion where the distance between adjacent fan blades is relatively small, the ventilation resistance of the air flow flowing on the blade surface of the fan blade increases. As a result, there is a possibility that the air blowing capability of the fan is reduced.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, and while exhibiting excellent air blowing capability, a fan in which generation of noise is effectively suppressed, a molding die used for manufacturing the fan, and It is to provide a fluid feeder including the fan.

  The fan according to the present invention includes a plurality of blade portions arranged at intervals in the circumferential direction. The blade portion has an inner edge portion disposed on the inner peripheral side and an outer edge portion disposed on the outer peripheral side. The blade portion is formed with a blade surface that extends between the inner edge portion and the outer edge portion. The blade surface is composed of a pressure surface disposed on the rotational direction side of the fan and a suction surface disposed on the back side of the pressure surface. As the fan rotates, a fluid flow that flows between the inner edge portion and the outer edge portion is generated on the blade surface. The blade portion has a blade cross section in which a concave portion is formed on the pressure surface and the suction surface when cut by a plane orthogonal to the rotation axis of the fan. The plurality of blade portions include a first blade portion and a second blade portion having blade sections having different shapes.

  According to the fan configured as described above, an air flow that flows in from one of the inner edge and the outer edge, passes through the blade surface, and flows out of the other of the inner edge and the outer edge when the fan rotates. Will occur. At this time, a vortex (secondary flow) of the air flow is generated in the recess, so that the air flow (main flow) passing over the blade surface flows along the outside of the vortex generated in the recess. As a result, the blade portion behaves like a thick wing having a blade section thickened by the amount of vortex formation. As a result, the fan blowing capability can be improved.

  In the present invention, the plurality of blade portions include a first blade portion and a second blade portion having blade sections having different shapes. Since the static pressure distribution on the pressure and suction surfaces of each blade is affected by the shape of the blade cross section, according to such a configuration, the air flow between adjacent blades and the flow between adjacent blades flow out. The incoming air flow will be different between the blades. Thereby, noise can be reduced.

  Preferably, the first blade portion and the second blade portion are different from each other in the position where the concave portion is formed. According to the fan configured as described above, the shape of the blade cross section is made different by changing the position where the recess is formed.

  Preferably, the first blade portion and the second blade portion have different numbers of recesses. According to the fan configured as described above, the shape of the blade cross section is made different by changing the number of the recessed portions formed.

  Preferably, the first blade portion and the second blade portion are different from each other in the shape of the recess. According to the fan configured as described above, the shape of the blade cross section is made different by changing the shape of the recess.

  Preferably, the plurality of blade portions are arranged so that angles formed by lines connecting the rotation axis of the fan and the outer edge portion are equal between adjacent blade portions.

  According to the fan configured as described above, the air flow flowing in and out between adjacent blade portions is transmitted to each blade portion even though the outer edge portion of each blade portion passes at a constant period as the fan rotates. Generation of noise can be suppressed by making the difference. Further, since noise reduction is realized, the interval between adjacent blade portions can be set to an optimum value based on the blowing capacity required for the fan. Thereby, the air flow between each blade | wing part can be stabilized, generation | occurrence | production of abnormal noise can be prevented, the increase in the ventilation resistance of the air flow between each blade | wing part can be suppressed, and the ventilation capability of a fan can be improved.

  Preferably, the plurality of blade portions are arranged so that the angles formed by the lines connecting the rotation axis of the fan and the centroid of the blade section of the blade portion are equal between adjacent blade portions.

  According to the fan configured as described above, the air flow between the adjacent blade portions is distributed between the blade portions even though the turbulent noise accompanying the air flow between the adjacent blade portions is uniform between the plurality of blade portions. Therefore, the generation of noise can be suppressed. Further, since noise reduction is realized, the interval between adjacent blade portions can be set to an optimum value based on the blowing capacity required for the fan. Thereby, the air flow between each blade | wing part can be stabilized, generation | occurrence | production of abnormal noise can be prevented, the increase in the ventilation resistance of the air flow between each blade | wing part can be suppressed, and the ventilation capability of a fan can be improved.

  Preferably, a plurality of types of blade portions having blade sections having different shapes are arranged in an irregular order. According to the fan configured as described above, an air flow between adjacent blade portions and an air flow flowing in and out between adjacent blade portions can be more effectively dispersed between the plurality of blade portions. .

  Preferably, the concave portion formed on the pressure surface forms a convex portion on the negative pressure surface, and the concave portion formed on the negative pressure surface forms a convex portion on the pressure surface. According to the fan configured as described above, the shape of the blade cross section in which the concave portion is formed in the pressure surface and the suction surface can be obtained with a simple configuration.

  Preferably, the blade portion has a blade cross section having a constant thickness between the inner edge portion and the outer edge portion. According to the fan configured as described above, even if a blade portion having a blade cross section with a constant thickness is used, it is possible to improve the fan blowing capability.

  Preferably, the blade portion has a bent portion formed by bending the center line of the blade cross section between the pressure surface and the suction surface at a plurality of locations. The concave portion is formed by a bent portion. According to the fan configured as described above, the strength of the blade portion can be increased by forming the bent portion.

  An inner space is formed inside the plurality of blade portions arranged in the circumferential direction, and an outer space is formed outside the inner space. Preferably, the fan described in any of the above is a centrifugal fan that sends fluid from the inner space to the outer space. According to the fan configured as described above, it is possible to improve the blowing capacity of the centrifugal fan and to effectively suppress the generation of noise.

  An inner space is formed inside the plurality of blade portions arranged in the circumferential direction, and an outer space is formed outside the inner space. Preferably, when the fan described in any of the above is viewed from the direction of the rotation axis of the fan, the fluid is taken into the inner space from the outer space on one side with respect to the rotation shaft, and the taken-in fluid is used as the rotation shaft. On the other hand, it is a once-through fan that is sent to the outer space on the other side. According to the fan configured as described above, it is possible to improve the blowing ability of the cross-flow fan and to effectively suppress the generation of noise.

  The fan described in any of the above is made of resin. The molding die according to the present invention is used for molding the fan. According to the molding die configured as described above, a resin fan can be manufactured.

  A fluid feeder according to the present invention includes a fan that includes any one of the above-described fans and a drive motor that is connected to the fans and rotates a plurality of blade portions. According to the fluid feeder configured in this way, it is possible to reduce the power consumption of the drive motor while maintaining a high blowing capacity.

  As described above, according to the present invention, a fan that exhibits excellent air blowing capability and that effectively suppresses noise generation, a molding die used for manufacturing the fan, and the fan are provided. A fluid feeder can be provided.

It is a perspective view which shows the centrifugal fan in Embodiment 1 of this invention. It is sectional drawing of the centrifugal fan along the II-II line | wire in FIG. FIG. 2 is a diagram schematically illustrating a phenomenon that occurs on the blade surface of a fan blade in the centrifugal fan in FIG. 1. It is sectional drawing which shows the fan blade used for the centrifugal fan in FIG. FIG. 2 is a diagram schematically showing the arrangement of fan blades in the centrifugal fan in FIG. 1. FIG. 6 is a diagram schematically showing a modification of the arrangement of fan blades shown in FIG. 5. It is sectional drawing which shows the metal mold | die used for manufacture at the time of manufacture of the centrifugal fan in FIG. It is sectional drawing which shows the air blower using the centrifugal fan in FIG. It is sectional drawing which shows the air blower along the IX-IX line in FIG. It is sectional drawing which shows the air cleaner using the centrifugal fan in FIG. It is sectional drawing which shows the 1st modification of multiple types of fan blade in FIG. It is sectional drawing which shows the 2nd modification of multiple types of fan blade in FIG. It is a side view which shows the cross-flow fan in Embodiment 3 of this invention. It is a cross-sectional perspective view which shows the cross-flow fan along the XIV-XIV line | wire in FIG. It is sectional drawing which shows the air conditioner in which the cross-flow fan shown in FIG. 13 is used. It is sectional drawing which expands and shows the blower outlet vicinity of the air conditioner in FIG. It is sectional drawing which shows the air flow produced in the blower outlet vicinity of the air conditioner in FIG. FIG. 17 is a cross-sectional view showing a phenomenon that occurs on the blade surface of the fan blade in the upstream region shown in FIG. 16. FIG. 17 is a cross-sectional view showing a phenomenon that occurs on the blade surface of the fan blade in the downstream region shown in FIG. 16.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

[Embodiment 1]
In the present embodiment, first, the structure of a centrifugal fan to which the fan of the present invention is applied will be described, and then the structure of a molding die used at the time of manufacturing the centrifugal fan and the blower using the centrifugal fan will be described. The structure of the air cleaner will be described.

(Explanation of centrifugal fan structure)
FIG. 1 is a perspective view showing a centrifugal fan according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the centrifugal fan along the line II-II in FIG.

  Referring to FIGS. 1 and 2, centrifugal fan 10 in the present embodiment has a plurality of fan blades 21. The centrifugal fan 10 has a substantially cylindrical appearance as a whole, and the plurality of fan blades 21 are disposed on the substantially cylindrical peripheral surface. The centrifugal fan 10 is integrally formed of resin. Centrifugal fan 10 rotates in the direction indicated by arrow 103 around a virtual central axis 101 shown in FIG.

  The centrifugal fan 10 is a fan that sends air taken from the inner peripheral side to the outer peripheral side by a plurality of rotating fan blades 21. The centrifugal fan 10 is a fan that sends out air in the radial direction from the rotation center side of the fan using centrifugal force. The centrifugal fan 10 is a sirocco fan. Centrifugal fan 10 is used at a rotational speed in a low-lay nozzle number region applied to a fan such as a household electric appliance.

  The centrifugal fan 10 further has an outer peripheral frame 13 as a support portion. The outer peripheral frame 13 is formed to extend annularly around the central axis 101. The outer peripheral frame 13 is disposed at a position spaced apart in the axial direction of the central shaft 101. One outer peripheral frame 13 is integrally formed with a boss portion 16 for connecting the centrifugal fan 10 to a drive motor via a disk portion 14.

  The plurality of fan blades 21 are arranged at intervals in the circumferential direction around the central axis 101. The plurality of fan blades 21 are supported by the outer peripheral frame 13 at both ends in the axial direction of the central shaft 101. The fan blade 21 is erected on one outer peripheral frame 13 and is formed to extend along the axial direction of the central shaft 101 toward the other outer peripheral frame 13.

  The fan blade 21 has an inner edge portion 26 and an outer edge portion 27. The inner edge portion 26 is disposed at an end portion on the inner peripheral side of the fan blade 21. The outer edge portion 27 is disposed at the outer peripheral end of the fan blade 21. The fan blade 21 is formed to be inclined in the circumferential direction about the central axis 101 from the inner edge portion 26 toward the outer edge portion 27. The fan blade 21 is formed to be inclined in the rotation direction of the centrifugal fan 10 from the inner edge portion 26 toward the outer edge portion 27.

  The fan blade 21 is formed with a blade surface 23 including a positive pressure surface 25 and a negative pressure surface 24. The positive pressure surface 25 is disposed on the rotational direction side of the centrifugal fan 10, and the negative pressure surface 24 is disposed on the back side of the positive pressure surface 25. When the centrifugal fan 10 rotates, a pressure distribution that is relatively large on the positive pressure surface 25 and relatively small on the negative pressure surface 24 is generated as an air flow is generated on the blade surface 23. The fan blade 21 has a generally curved shape between the inner edge portion 26 and the outer edge portion 27 so that the positive pressure surface 25 side is concave and the negative pressure surface 24 side is convex.

  FIG. 2 shows a blade cross section of the fan blade 21 when cut along a plane orthogonal to the central axis 101 that is the rotation axis of the centrifugal fan 10.

  The fan blade 21 is formed to have the same blade cross section even if it is cut at any position in the axial direction of the central shaft 101. The fan blade 21 is formed to have a thin blade section between the inner edge portion 26 and the outer edge portion 27. The fan blade 21 is formed to have a substantially constant thickness (the length between the positive pressure surface 25 and the negative pressure surface 24) between the inner edge portion 26 and the outer edge portion 27.

  The fan blade 21 has a blade cross section in which a concave portion 57 is formed on the pressure surface 25 of the blade surface 23 and a concave portion 56 is formed on the negative pressure surface 24 of the blade surface 23. A plurality of concave portions 56 and 57 are formed in at least one of the positive pressure surface 25 and the negative pressure surface 24.

  In the present embodiment, a plurality of recesses 57 (recesses 57p and 57q) are formed on the positive pressure surface 25. On the positive pressure surface 25, convex portions 52 (52p, 52q, 52r) are further formed. The convex portion 52 is formed so as to protrude in the rotation direction of the centrifugal fan 10. A concave portion 57 is formed by a valley portion between the convex portions 52 arranged adjacent to each other. For example, a concave portion 57p is formed by a valley portion between the convex portion 52p and the convex portion 52q. The concave portions 57 and the convex portions 52 are formed alternately in the direction connecting the inner edge portion 26 and the outer edge portion 27. The recess 57 has a substantially U-shaped cross section.

  A plurality of convex portions 51 (convex portions 51p, 51q) are further formed on the negative pressure surface 24. The convex portion 51 is formed to protrude in the direction opposite to the rotation direction of the cross-flow fan 100. A concave portion 56 is formed by the valley portion between the convex portions 51 arranged adjacent to each other. In the present embodiment, the concave portion 56 is formed by the valley portion between the convex portion 51p and the convex portion 51q. Yes. The concave portions 56 and the convex portions 51 are formed alternately in the direction connecting the inner edge portion 26 and the outer edge portion 27. The recess 56 has a substantially U-shaped cross-sectional shape.

  The concave portion 57 and the convex portion 51 are formed at positions corresponding to the front and back of the positive pressure surface 25 and the negative pressure surface 24, and the convex portion 52 and the concave portion 56 are formed at positions corresponding to the front and back of the positive pressure surface 25 and the negative pressure surface 24. Yes. In the present embodiment, the concave portion 57 formed on the pressure surface 25 forms the convex portion 51 on the negative pressure surface 24, and the concave portion 56 formed on the negative pressure surface 24 forms the convex portion 52 on the positive pressure surface 25. The concave portion and the convex portion formed on the positive pressure surface 25 and the negative pressure surface 24 corresponding to the front and back surfaces have the same shape.

  The recesses 57 and 56 have a groove shape extending along the axial direction of the central shaft 101. The groove portion including the recesses 57 and 56 is formed to extend continuously between one end and the other end of the fan blade 21 in the axial direction of the central shaft 101. A groove portion composed of the concave portions 57 and 56 is formed to extend linearly between one end and the other end of the fan blade 21 in the axial direction of the central shaft 101.

  In the present embodiment, the number of the recesses 57 formed on the pressure surface 25 is larger than the number of the recesses 56 formed on the suction surface 24.

  FIG. 2 shows a center line 106 in the thickness direction of the blade cross section of the fan blade 21 (the direction connecting the pressure surface 25 and the suction surface 24). The fan blade 21 has a bent portion 41 where the center line 106 of the blade cross section of the fan blade 21 is bent at a plurality of locations between the inner edge portion 26 and the outer edge portion 27. The concave portions 56 and 57 are formed by the bent portion 41.

  In the present embodiment, the fan blade 21 has bent portions 41 at three positions between the inner edge portion 26 and the outer edge portion 27. The fan blade 21 has a bent portion 41 </ b> A disposed in the vicinity of the inner edge portion 26 and the outer edge portion 27, and a bent portion 41 </ b> B disposed in the blade central portion between the inner edge portion 26 and the outer edge portion 27. The bent portion 41 </ b> A has a concave portion 57 formed on the positive pressure surface 25 and a convex portion 51 formed on the negative pressure surface 24. The bent portion 41 </ b> B has a convex portion 52 formed on the positive pressure surface 25 and a concave portion 56 formed on the negative pressure surface 24.

  With such a configuration, the concave portion 57 is formed in the vicinity of the inner edge portion 26 and the outer edge portion 27, and the concave portion 56 is further formed in the blade central portion between the inner edge portion 26 and the outer edge portion 27. The fan blade 21 has a substantially W-shaped blade cross-sectional shape.

  The bent portion 41 is bent at at least one location so that the depth T of the concave portions 56 and 57 is larger than the thickness t of the fan blade 21. The bent portions 41 are formed so that the folding directions are alternately opposite to each other in the direction connecting the inner edge portion 26 and the outer edge portion 27. The bent portion 41 is formed to be bent so as to be rounded. The bent portion 41 may be formed to be bent so as to form a corner portion.

  FIG. 3 is a diagram schematically showing a phenomenon that occurs on the blade surface of the fan blade in the centrifugal fan in FIG. 1 to 3, when the centrifugal fan 10 is rotated, as shown by an arrow 102 in FIG. 1, the centrifugal fan 10 flows in from the inner edge portion 26, passes through the blade surface 23, and flows out from the outer edge portion 27. An air flow is generated between adjacent fan blades 21. At this time, the vortex 32 (secondary flow) of the air flow is generated in the recesses 56 and 57 formed in the blade surface 23, whereby the air flow 31 (main flow) passing over the blade surface 23 is converted into the recesses 56 and 57. It flows along the outside of the vortex 32 generated in 57.

  As a result, the fan blade 21 behaves like a thick-walled blade with a blade section thickened by the depth of the recesses 56 and 57 in which the vortex 32 is formed, despite having a thin blade section. Indicates. As a result, the lift force generated in the vicinity of the inner edge portion 26 in which the concave portions 56 and 57 are formed can be greatly increased.

  Further, the strength of the fan blade 21 can be improved by the bent structure by the bent portion 41. As a result, although the centrifugal fan 10 is a resin fan having a thin blade section, the reliability with respect to the strength of the fan can be improved. Further, it is possible to make the fan blade 21 thinner by the amount of improved strength. Thereby, the centrifugal fan 10 can be reduced in weight or cost.

  For the reasons described above, it is possible to realize the centrifugal fan 10 having a blade section having a high lift-drag ratio, thin and light, and high strength.

  FIG. 4 is a cross-sectional view showing a fan blade used in the centrifugal fan in FIG. In the drawing, a cross section of the fan blade shown in FIG. 2 is shown. Referring to FIG. 3, in centrifugal fan 10 in the present embodiment, a plurality of fan blades 21 are composed of a plurality of types of fan blades 21A, 21B, 21C, 21D, and 21E. The fan blades 21A to 21E have blade sections having different shapes. A plurality of fan blades 21A to 21E are provided.

  The shape of the fan blades 21A to 21E will be described more specifically. The fan blades 21A to 21E have a substantially W-shaped blade cross-section in common, but the positions where the recesses 56 and 57 are formed are different from each other. When attention is paid to the position where the concave portion 56 is formed, in the fan blade 21A, the concave portion 56 is formed at a position close to the inner edge portion 26, and as the fan blades 21B, 21C, and 21D are formed, the concave portion 56 moves away from the inner edge portion 26. 27 is formed at a position approaching 27. And in the fan blade 21E, the recessed part 56 is formed in the position close | similar to the outer edge part 27. As shown in FIG. The concave portion 57p and the concave portion 57q are also formed so as to move away from the inner edge portion 26 and approach the outer edge portion 27 as the fan blades 21B, 21C, 21D, and 21E move from the fan blade 21A.

  As shown typically in the fan blade 21A in FIG. 4, it is preferable to assume a negative pressure surface 24 ′ that smoothly extends from the top of the convex portion 52 toward the top of the convex portion 51 above the concave portion 56. The fan blades 21 </ b> A to 21 </ b> E are formed such that the negative pressure surface 24 ′ of each fan blade has different contours between the inner edge portion 26 and the outer edge portion 27 in the cross section shown in FIG. 4.

  FIG. 5 is a diagram schematically showing the arrangement of fan blades in the centrifugal fan in FIG. Referring to FIG. 5, fan blades 21 </ b> A, 21 </ b> B, 21 </ b> C, 21 </ b> D, and 21 </ b> E are arranged so as to be arranged in an irregular (random) order in the circumferential direction centering on central axis 101. That is, the fan blades 21A to 21E are repeatedly arranged in a regular order (for example, fan blade 21A → 21B → 21C → 21D → 21E → 21A → 21B → 21C → 21D → 21E → 21A → 21B...). There is no arrangement.

  In the example shown in FIG. 5, the fan blades 21C, 21E, 21A, 21D, 21B, 21A, 21B, 21C, 21D, 21E, 21B, 21D, 21A, 21C, 21E are arranged in order.

  In the above example, the five types of fan blades 21A to 21E are considered as one set, and a plurality of sets having different arrangements of fan blades 21A to 21E are sequentially arranged. A plurality of fan blades 21A to 21E may be prepared, and an appropriate fan blade may be selected from the plurality of fan blades and arranged in order. Further, if the fan blades 21A to 21E are arranged without regularity as a whole, specific types of fan blades may be continuously arranged. Further, the number of fan blades of the fan blades 21A to 21E used in the centrifugal fan 10 may not all be the same. Further, all of the fan blades 21 used in the centrifugal fan 10 may have different blade cross-sectional shapes. The number of types of fan blades 21 used is preferably 3 or more, more preferably 4 or more.

  In centrifugal fan 10 in the present embodiment, a plurality of fan blades 21 have an equal angle α formed by a line connecting central axis 101 and outer edge portion 27 of each fan blade 21 between adjacent fan blades 21. It is arranged. Further, the plurality of fan blades 21 may be arranged so that the angles formed by the lines connecting the central shaft 101 and the inner edge portion 26 of each fan blade 21 between the adjacent fan blades 21 are equal.

  FIG. 6 is a diagram schematically showing a modification of the arrangement of the fan blades shown in FIG. Referring to FIG. 6, the structure in which a plurality of types of fan blades 21A, 21B, 21C, 21D, and 21E having blade sections of different shapes are arranged in an irregular order is the same as the arrangement shown in FIG. . In this modification, the plurality of fan blades 21 are arranged so that the angles β formed by the lines connecting the central axis 101 and the centroids of the blade cross sections of the fan blades 21 between the adjacent fan blades 21 are equal. . The centroid of the blade cross section of the fan blade 21 corresponds to the center of gravity of the blade cross section, and is obtained by a value obtained by dividing the cross sectional primary moment of the blade cross section by the cross sectional area of the entire blade cross section.

  A plurality of fan blades 21 may be arranged so as to satisfy both the form of arrangement shown in FIG. 5 and the form of arrangement shown in FIG.

  As described above with reference to FIGS. 4 to 6, the centrifugal fan 10 uses fan blades 21 </ b> A, 21 </ b> B, 21 </ b> C, 21 </ b> D, 21 </ b> E having different positions where the recesses 56, 57 are formed. The blade cross sections are different among the plurality of fan blades 21. Since the shape of the blade cross section of the fan blade 21 affects the static pressure distribution on the pressure surface 25 and the suction surface 24 when the centrifugal fan 10 rotates, the air flow between the adjacent fan blades 21, the outer edge portion 27, and the inner edge The air flow flowing in and out between the adjacent fan blades 21 through the portion 26 differs between the fan blades 21.

  On the other hand, in the example shown in FIG. 5, the plurality of fan blades 21 are arranged so that the angles α formed by the lines connecting the central axis 101 and the outer edge portion 27 of each fan blade 21 between the adjacent fan blades 21 are equal. Has been. Even in such a case, the air flow flowing in and out between the adjacent fan blades 21 differs depending on each fan blade 21, so that the air flow at the location where the outer edge portion 27 of the fan blade 21 and the fan casing approach each other is changed. A disturbance can be caused. Thereby, the timing of the pressure fluctuation when the outer edge portion 27 of the fan blade 21 passes through the approaching portion can be excluded from a certain period, and as a result, the narrow-band noise caused by the blade passing sound (nZ sound) is acceptable. It can be suppressed to.

  Further, in the example shown in FIG. 6, a plurality of fan blades 21 are set so that the angles β formed by the lines connecting the central shaft 101 and the centroids of the blade cross sections of the respective fan blades 21 between the adjacent fan blades 21 are equal. Is arranged. Even in such a case, since the air flow between the adjacent fan blades 21 is different depending on each fan blade 21, the narrow-band noise caused by the air flow between the fan blades 21 can be suppressed to an acceptable level.

  As described above, since the reduction of the narrow band noise is realized, in any of the examples shown in FIGS. 5 and 6, between the adjacent fan blades 21 based on the blowing capacity required for the centrifugal fan 10. Can be set to an optimum value. As a result, it is possible to prevent a phenomenon such as a partial reverse flow of the air flow between the adjacent fan blades 21 and to stabilize the air flow between the fan blades 21. As a result, it is possible to prevent the generation of low-frequency noise (abnormal noise) and increase the blowing capacity. In addition, it is possible to increase the air blowing capability by preventing the phenomenon that the air flow resistance between the fan blades 21 is remarkably increased.

  The centrifugal fan 10 is applied to a device in which the pressure loss of the air flow loaded on the fan is larger than that of a once-through fan described later. In this case, since the backflow of the air flow is likely to occur between the adjacent fan blades 21, the structure of the present invention that can prevent such a phenomenon is applied to the centrifugal fan 10 more effectively.

  The structure of the centrifugal fan 10 according to the first embodiment of the present invention described above will be described collectively. The centrifugal fan 10 according to the present embodiment is a plurality of blade portions arranged at intervals in the circumferential direction. The fan blade 21 is provided. The fan blade 21 has an inner edge portion 26 disposed on the inner peripheral side and an outer edge portion 27 disposed on the outer peripheral side. The fan blade 21 is formed with a blade surface 23 extending between the inner edge portion 26 and the outer edge portion 27. The blade surface 23 is composed of a positive pressure surface 25 disposed on the rotational direction side of the fan and a negative pressure surface 24 disposed on the back side of the positive pressure surface 25. As the fan rotates, an air flow is generated on the blade surface 23 as a fluid flow that flows between the inner edge portion 26 and the outer edge portion 27. The fan blade 21 has a blade cross section in which concave portions 56 and 57 are formed in the positive pressure surface 25 and the negative pressure surface 24 when cut by a plane orthogonal to the central axis 101 as the rotation axis of the fan. The plurality of fan blades 21 include fan blades 21A to 21E having blade sections having different shapes.

(Description of molds, blowers and air purifier structures)
FIG. 7 is a cross-sectional view showing a molding die used when the centrifugal fan in FIG. 1 is manufactured. Referring to FIG. 7, the molding die 110 has a fixed side die 114 and a movable side die 112. The fixed side mold 114 and the movable side mold 112 define a cavity 116 having substantially the same shape as the centrifugal fan 10 and into which a fluid resin is injected.

  The molding die 110 may be provided with a heater (not shown) for improving the fluidity of the resin injected into the cavity 116. The installation of such a heater is particularly effective when using a synthetic resin with increased strength such as an AS (acrylonitrile and styrene copolymer compound) resin containing glass fibers.

  The cross-flow fan 100 according to the third embodiment to be described later is also manufactured by a mold having the same structure as the molding mold 110 in FIG.

  FIG. 8 is a cross-sectional view showing a blower using the centrifugal fan in FIG. FIG. 9 is a cross-sectional view showing the blower along the line IX-IX in FIG. 8. With reference to FIGS. 8 and 9, blower 120 has drive motor 128, centrifugal fan 10, and casing 129 in exterior casing 126.

  The output shaft of the drive motor 128 is connected to a boss portion 16 that is molded integrally with the centrifugal fan 10. The casing 129 has a guide wall 129a. The guide wall 129 a is formed by a substantially 3/4 arc arranged on the outer periphery of the centrifugal fan 10. The guide wall 129 a increases the speed of the airflow while guiding the airflow generated by the rotation of the fan blade 21 in the rotation direction of the fan blade 21.

  The casing 129 is formed with a suction part 130 and a blowing part 127. The suction part 130 is formed on the extension of the central shaft 101. The blowing portion 127 is formed to be opened from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a. The blowing portion 127 has a rectangular tube shape protruding from a part of the guide wall 129a to one side in the tangential direction of the guide wall 129a.

  The centrifugal fan 10 rotates in the direction indicated by the arrow 103 by driving the drive motor 128. At this time, air is taken into the casing 129 from the suction portion 130 and sent out from the inner peripheral space 131 of the centrifugal fan 10 to the outer peripheral space 132. The air sent out to the outer peripheral side space 132 flows in the circumferential direction along the direction indicated by the arrow 104 and is blown to the outside through the blowing unit 127.

  FIG. 10 is a sectional view showing an air cleaner using the centrifugal fan in FIG. Referring to FIG. 10, the air cleaner 140 includes a housing 144, a blower 150, a duct 145, and a (HEPA: High Efficiency Particulate Air Filter) filter 141.

  The housing 144 has a rear wall 144a and a top wall 144b. The housing 144 is formed with a suction port 142 for sucking air in a room where the air purifier 140 is installed. The suction port 142 is formed in the rear wall 144a. The housing 144 further has a blowout port 143 that discharges clean air toward the room. The outlet 143 is formed in the top wall 144b. In general, the air cleaner 140 is installed near the wall so that the rear wall 144a faces the indoor wall.

The filter 141 is disposed inside the housing 144 so as to face the suction port 142. The air introduced into the housing 144 through the suction port 142 is
Passes through the filter 141. Thereby, the foreign material in the air is removed.

  The blower 150 is provided for sucking indoor air into the housing 144 and sending out air purified by the filter 141 into the room through the outlet 143. The blower 150 includes the centrifugal fan 10, a casing 152, and a drive motor 151. The casing 152 has a guide wall 152a. The casing 152 is formed with a suction part 153 and a blowing part 154.

  The duct 145 is provided above the blower 150 and is provided as an air guide path that guides clean air from the casing 152 to the outlet 143. The duct 145 has a shape that forms a rectangular tube whose lower end is connected to the blowing portion 154 and whose upper end is open. The duct 145 is formed so as to guide the clean air blown out from the blowing portion 154 to the laminar flow toward the blowing port 143.

  In the air cleaner 140 having such a configuration, the fan blades 21 are rotated by driving the blower 150, and the indoor air is sucked into the housing 144 from the suction port 142. At this time, an air flow is generated between the suction port 142 and the blowout port 143, and foreign matters such as dust contained in the sucked air are removed by the filter 141.

  The clean air obtained through the filter 141 is sucked into the casing 152. At this time, the clean air sucked into the casing 152 becomes a laminar flow by the guide wall 152 a around the fan blade 21. The laminar air is guided to the blowing part 154 along the guiding wall 152a and is blown into the duct 145 from the blowing part 154. Air is discharged from the outlet 143 toward the external space.

  In the present embodiment, the air cleaner has been described as an example, but in addition to this, for example, an air conditioner (air conditioner), a humidifier, a cooling device, a device that sends out fluid such as a ventilation device, etc. The centrifugal fan according to the present invention can be applied.

  According to the centrifugal fan 10 according to the first embodiment of the present invention described above, by forming the recesses 56 and 57 in the fan blade 21, a low ray nozzle number region applied to a fan such as a household electric appliance. , The lift generated with the rotation of the fan blade 21 can be greatly increased. Further, by using the fan blades 21A to 21E having blade sections having different shapes, it is possible to reduce the narrow band noise generated with the rotation of the fan. Therefore, it is possible to increase the blowing capacity of the centrifugal fan 10 while suppressing the generation of noise.

  Moreover, according to the air cleaner 140 in this Embodiment, the air cleaner 140 which can contribute to energy saving by reducing the power consumption of the drive motor 151 by using the centrifugal fan 10 which is excellent in ventilation capability is realized. can do. In addition, by using the centrifugal fan 10 that can reduce noise, the air cleaner 140 having excellent quiet performance can be realized.

[Embodiment 2]
In the present embodiment, various modifications of the plurality of types of fan blades shown in FIG. 4 will be described.

  FIG. 11 is a cross-sectional view showing a first modification of the plurality of types of fan blades in FIG. Referring to FIG. 11, in the present modification, the plurality of fan blades 21 are composed of a plurality of types of fan blades 21A, 21B, 21C, and 21D having blade sections having different shapes.

  More specifically, the shapes of the fan blades 21A to 21D are different from each other in the number of the concave portions 56 and 57 formed in the fan blades 21A to 21D. One recess 56 and two recesses 57 are formed in the fan blade 21A, two recesses 56 and three recesses 57 are formed in the fan blade 21B, and three fan recesses are formed in the fan blade 21C. A recess 56 and four recesses 57 are formed, and four recesses 56 and five recesses 57 are formed in the fan blade 21D.

  FIG. 12 is a cross-sectional view showing a second modification of the plurality of types of fan blades in FIG. Referring to FIG. 12, in the present modification, the plurality of fan blades 21 are composed of a plurality of types of fan blades 21A, 21B, 21C, and 21D having blade sections having different shapes. Each of the fan blades 21 </ b> A to 21 </ b> D is formed to be bent at a plurality of positions between the inner edge portion 26 and the outer edge portion 27. In addition, the corner | angular part may have some roundness in consideration of the process of extracting the fan blade 21 from the metal mold for resin molding.

  The shape of the fan blades 21A to 21D will be described more specifically. The fan blades 21A to 21D are different from each other in the position and number of the concave portions 56 and 57 and the shapes of the concave portions 56 and 57. The fan blade 21A has three recesses 56 and four recesses 57, and each fan blade of the fan blades 21B to 21D has two recesses 56 and three recesses 57. The concave portions 56 and 57 formed in the fan blades 21A to 21D basically have a triangular shape in which the concave shape is defined by two sides, but one concave portion 56 formed in the fan blade 21B and the fan blade 21C. One recess 57 formed in the shape of a quadrangle having a concave shape defined by three sides.

  As shown in FIGS. 11 and 12, a plurality of types of fan blades 21 having different shapes can be easily obtained by changing the positions, numbers, and shapes of the recesses 56 and 57.

  According to the centrifugal fan in the second embodiment of the present invention configured as described above, the effects described in the first embodiment can be obtained in the same manner.

[Embodiment 3]
In this embodiment, the structure of a cross-flow fan to which the fan of the present invention is applied will be described, and then the structure of an air conditioner (air conditioner) in which the cross-flow fan is used will be described. Note that the cross-flow fan in the present embodiment is partially provided with the same structure as the centrifugal fan 10 in the first embodiment. Hereinafter, the description of the overlapping structure will not be repeated.

(Description of cross-flow fan structure)
FIG. 13 is a side view showing a cross-flow fan according to Embodiment 3 of the present invention. FIG. 14 is a cross-sectional perspective view showing the cross-flow fan along the line XIV-XIV in FIG. 13.

  Referring to FIGS. 13 and 14, cross-flow fan (cross flow fan) 100 in the present embodiment has a plurality of fan blades 21. Cross-flow fan 100 has a substantially cylindrical appearance as a whole, and a plurality of fan blades 21 are arranged on the substantially cylindrical peripheral surface. Cross-flow fan 100 is integrally formed of resin. Cross-flow fan 100 rotates in the direction indicated by arrow 103 about a virtual center axis 101 shown in the figure.

  The cross-flow fan 100 is a fan that blows air in a direction orthogonal to the central axis 101 that is a rotation axis by a plurality of rotating fan blades 21. Cross-flow fan 100, when viewed from the axial direction of central axis 101, takes air from the outer space on one side with respect to central axis 101 into the inner space of the fan, and further captures the air with respect to central axis 101. This is a fan sent out to the outer space on the other side. Cross-flow fan 100 forms an air flow that flows in a direction crossing center axis 101 in a plane orthogonal to center axis 101. Cross-flow fan 100 forms a planar blow-out flow parallel to central axis 101.

  Cross-flow fan 100 is used at a rotational speed in a low-lay nozzle number region applied to a fan such as a household electric appliance.

  Cross-flow fan 100 is configured by combining a plurality of impellers 12 arranged in the axial direction of central shaft 101. In each impeller 12, the plurality of fan blades 21 are provided at intervals in the circumferential direction around the central axis 101.

  Cross-flow fan 100 further includes an outer peripheral frame 13 as a support portion. The outer peripheral frame 13 has a ring shape extending annularly around the central axis 101. The outer peripheral frame 13 has an end surface 13a and an end surface 13b. The end surface 13 a is formed so as to face one direction along the axial direction of the central axis 101. The end surface 13 b is disposed on the back side of the end surface 13 a and is formed to face the other direction along the axial direction of the central axis 101.

  The outer peripheral frame 13 is provided between the adjacent impellers 12 in the axial direction of the central shaft 101.

  When attention is paid to the impeller 12A and the impeller 12B in FIG. 13 that are arranged adjacent to each other, the plurality of fan blades 21 provided on the impeller 12A are erected on the end surface 13a in the axial direction of the central shaft 101. It is formed so as to extend in a plate shape along. The plurality of fan blades 21 provided in the impeller 12 </ b> B are erected on the end surface 13 b and are formed to extend in a plate shape along the axial direction of the central shaft 101.

  The plurality of fan blades 21 are configured by the same structure as the fan blade 21 described in the first embodiment (a structure in which recesses 56 and 57 are formed, and a plurality of types of fan blades 21A to 21E having blade sections having different shapes. The fan blades 21A to 21E are arranged in an irregular order).

  However, the cross-flow fan 100 according to the present embodiment differs from the centrifugal fan 10 according to the first embodiment in that a plurality of fan blades 21 are arranged at a random pitch. This random pitch is realized, for example, by arranging a plurality of fan blades 21 at unequal intervals according to a random number normal distribution. The plurality of impellers 12 are formed so that the fan blades 21 are arranged in the same manner. That is, in each impeller 12, the intervals at which the plurality of fan blades 21 are arranged and the order of the fan blades 21 arranged at the intervals are the same among the plurality of impellers 12.

  The plurality of impellers 12 are stacked such that a shift angle θ is generated between the adjacent impellers 12 when viewed from the axial direction of the central shaft 101. For example, when attention is paid to the impeller 12A, the impeller 12B, and the impeller 12C in FIG. 13 that are arranged adjacent to each other in the order listed, the impeller 12B is more than the impeller 12A and the impeller 12B. The fan blades 21 are stacked so as to be shifted from the position where the fan blades 21 overlap with each other in the axial direction of the central axis 101 by shifting the central axis 101 about the angle θ. Furthermore, the impeller 12C is shifted with respect to the impeller 12B from the position where all the fan blades 21 of the impeller 12B and the impeller 12C overlap in the axial direction of the central shaft 101 with an angle θ (blade) When viewed from the vehicle 12A, they are stacked so as to be shifted by 2θ).

  The reason why the shift angle θ is provided is that the blade passing sound generated in each impeller 12 is canceled by mutually shifting the position of the fan blade 21 between the plurality of impellers 12 in the axial direction of the central shaft 101. This is to attenuate.

(Description of air conditioner structure)
FIG. 15 is a cross-sectional view showing an air conditioner in which the cross-flow fan shown in FIG. 13 is used. Referring to FIG. 15, an air conditioner 210 is installed indoors and an indoor unit 220 provided with an indoor heat exchanger 229 and an outdoor heat exchanger and a compressor installed outside are not shown. It consists of an outdoor unit. The indoor unit 220 and the outdoor unit are connected by piping for circulating the refrigerant gas between the indoor heat exchanger 229 and the outdoor heat exchanger.

  The indoor unit 220 includes a blower 215. The blower 215 includes a cross-flow fan 100, a drive motor (not shown) for rotating the cross-flow fan 100, and a casing 222 for generating a predetermined air flow as the cross-flow fan 100 rotates.

  The casing 222 has a cabinet 222A and a front panel 222B. The cabinet 222A is supported on the wall surface of the room, and the front panel 222B is detachably attached to the cabinet 222A. A blowout port 225 is formed in the gap between the lower end portion of the front panel 222B and the lower end portion of the cabinet 222A. The outlet 225 is formed in a substantially rectangular shape extending in the width direction of the indoor unit 220 and is provided facing the front lower side. A grid-like suction port 224 is formed on the upper surface of the front panel 222B.

  An air filter 228 for collecting and removing dust contained in the air sucked from the suction port 224 is provided at a position facing the front panel 222B. In a space formed between the front panel 222B and the air filter 228, an air filter cleaning device (not shown) is provided. The dust accumulated in the air filter 228 is automatically removed by the air filter cleaning device.

  Inside the casing 222, an air passage 226 through which air flows from the suction port 224 toward the blowout port 225 is formed. The blowout port 225 is provided with a vertical louver 232 that can change the blowout angle in the left-right direction, and a plurality of horizontal louvers 231 that can change the blowout angle in the vertical direction to the front upper, horizontal, forward lower, and right down directions. It has been.

  An indoor heat exchanger 229 is disposed between the cross-flow fan 100 and the air filter 228 on the path of the air passage 226. The indoor heat exchanger 229 has meandering refrigerant pipes (not shown) arranged in a plurality of stages in the vertical direction and in a plurality of rows in the front-rear direction. The indoor side heat exchanger 229 is connected to a compressor of an outdoor unit installed outdoors, and the refrigeration cycle is operated by driving the compressor. By the operation of the refrigeration cycle, the indoor heat exchanger 229 is cooled to a temperature lower than the ambient temperature during the cooling operation, and the indoor heat exchanger 229 is heated to a temperature higher than the ambient temperature during the heating operation.

  16 is an enlarged cross-sectional view showing the vicinity of the air outlet of the air conditioner in FIG. Referring to FIGS. 15 and 16, casing 222 has a front wall portion 251 and a rear wall portion 252. The front wall portion 251 and the rear wall portion 252 are disposed facing each other with a space therebetween.

  On the path of the air passage 226, the cross-flow fan 100 is disposed so as to be positioned between the front wall portion 251 and the rear wall portion 252. The front wall portion 251 is formed with a protruding portion 253 that protrudes toward the outer peripheral surface of the cross-flow fan 100 and makes the gap between the cross-flow fan 100 and the front wall portion 251 minute. The rear wall portion 252 is formed with a protruding portion 254 that protrudes toward the outer peripheral surface of the cross-flow fan 100 and makes the gap between the cross-flow fan 100 and the rear wall portion 252 minute.

  The casing 222 has an upper guide portion 256 and a lower guide portion 257. The air passage 226 is defined by the upper guide portion 256 and the lower guide portion 257 on the downstream side of the air flow from the cross-flow fan 100.

  The upper guide portion 256 and the lower guide portion 257 are continuous from the front wall portion 251 and the rear wall portion 252, respectively, and extend toward the blowout port 225. The upper guide portion 256 and the lower guide portion 257 bend the air sent out by the cross-flow fan 100 so that the upper guide portion 256 is on the inner peripheral side and the lower guide portion 257 is on the outer peripheral side. It is formed to guide. The upper guide portion 256 and the lower guide portion 257 are formed so that the cross-sectional area of the air passage 226 increases as it goes from the cross-flow fan 100 toward the outlet 225.

  In the present embodiment, the front wall portion 251 and the upper guide portion 256 are formed integrally with the front panel 222B. A rear wall portion 252 and a lower guide portion 257 are formed integrally with the cabinet 222A.

  In the first embodiment, the phenomenon that the air flow is disturbed in the location where the outer edge portion 27 of the fan blade 21 and the fan casing approach is described. However, in the air conditioner 210, this approach location is It corresponds to a space where the front wall portion 251 and the fan blade 21 face each other.

  FIG. 17 is a cross-sectional view showing the air flow generated in the vicinity of the air outlet of the air conditioner in FIG. With reference to FIGS. 15 to 17, an upstream outer space 246 is formed on the path on the air passage 226 so as to be located on the upstream side of the air flow with respect to the cross-flow fan 100. The inner space 247 is formed on the inner peripheral side of the plurality of fan blades 21 arranged in the direction, and the downstream outer space 248 is formed on the downstream side of the cross-flow fan 100 in the air flow. .

  When the cross-flow fan 100 is rotated, the air flowing from the upstream outer space 246 to the inner space 247 through the blade surface 23 of the fan blade 21 in the upstream region 241 of the air passage 226 with the protrusions 253 and 254 as a boundary. A flow 261 is formed, and air flows from the inner space 247 through the blade surface 23 of the fan blade 21 toward the downstream outer space 248 in the downstream region 242 of the air passage 226 with the protrusions 253 and 254 as a boundary. 261 is formed. At this time, an air flow vortex 262 is formed at a position adjacent to the front wall 251.

  FIG. 18 is a cross-sectional view showing a phenomenon that occurs on the blade surface of the fan blade in the upstream region shown in FIG.

  Referring to FIG. 18, when an air flow from the upstream outer space 246 toward the inner space 247 is formed in the upstream region 241 in FIG. 16, on the blade surface 23 of the fan blade 21, from the outer edge portion 27. An air flow that flows in, passes over the blade surface 23, and flows out from the inner edge portion 26 is generated. At this time, a clockwise air flow vortex 63 (secondary flow) is formed in the concave portion 57 formed in the positive pressure surface 25, and a counterclockwise air flow is formed in the concave portion 56 formed in the negative pressure surface 24. Vortex 62 is generated. As a result, the air flow 61 (main flow) passing over the blade surface 23 flows along the outside of the vortices 63 and 62 generated in the recesses 57 and 56.

  FIG. 19 is a cross-sectional view showing a phenomenon that occurs on the blade surface of the fan blade in the downstream region shown in FIG.

  Referring to FIG. 19, when an air flow from the inner space 247 toward the downstream outer space 248 is formed in the downstream region 242 in FIG. 16, on the blade surface 23 of the fan blade 21, from the inner edge portion 26. An air flow that flows in, passes over the blade surface 23 and flows out from the outer edge portion 27 is generated. At this time, a counterclockwise air flow vortex 68 (secondary flow) is formed in the concave portion 57 formed in the positive pressure surface 25, and a clockwise air flow is formed in the concave portion 56 formed in the negative pressure surface 24. Vortex 67 is generated. Thereby, the air flow 66 (main flow) passing over the blade surface 23 flows along the outside of the vortices 68 and 67 generated in the recesses 57 and 56.

  That is, in the once-through fan 100, when the fan blade 21 moves from the upstream region 241 to the downstream region 242, the air flow direction on the blade surface 23 is reversed, and accordingly, vortices generated in the recesses 57 and 56 are reversed. The direction of rotation is also reversed.

  In cross-flow fan 100 in the present embodiment, vortices (secondary flow) are formed in recesses 57 and 56, so that fan blade 21 behaves like a thick-walled blade with a thickened blade section. Show. As a result, the lift generated by the fan blade 21 can be greatly increased.

  Further, in cross-flow fan 100, fan blades 21A, 21B, 21C, 21D, and 21E in FIG. 4 are used in which positions where concave portions 56 and 57 are formed are different. With this configuration, it is possible to reduce the narrow band noise caused by the blade passing sound (nZ sound) and the narrow band noise caused by the air flow between the fan blades 21. In addition, since the narrow-band noise is reduced as described above, the interval between the adjacent fan blades 21 can be set to an optimum value based on the air blowing capacity required for the cross-flow fan 100. That is, when a plurality of fan blades 21 are arranged at a random pitch, it is possible to minimize variations in pitch.

  As shown in FIG. 13, the cross-flow fan 100 is configured by arranging a plurality of impellers 12 in the axial direction of the central shaft 101. For this reason, in the cross-flow fan 100, compared with the centrifugal fan already demonstrated, the pressure loss of the air flow loaded on the fan of each impeller 12 becomes small, and it is hard to produce the backflow of an air flow between the adjacent fan blades 21. . For this reason, in this Embodiment, generation | occurrence | production of the low frequency noise (abnormal noise) resulting from the backflow of an air flow can be suppressed, taking the structure which arranges the several fan blade 21 by random pitch.

  In the cross-flow fan 100, a configuration in which a plurality of fan blades 21 as shown in FIGS. 5 and 6 are arranged at an equal pitch may be applied. Further, in the present embodiment, the air conditioner has been described as an example. However, in addition to this, for example, an air purifier, a humidifier, a cooling device, a ventilating device, or the like can be used as a flow-through device in the present invention. It is possible to apply a fan.

  According to cross-flow fan 100 and air conditioner 210 according to Embodiment 3 of the present invention configured as described above, the effects described in Embodiment 1 can be similarly obtained.

  A new fan may be configured by appropriately combining the fan structures described in the first to third embodiments described above. For example, the cross-flow fan 100 in the third embodiment may be configured using the fan blade described in the second embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is mainly applied to household electric appliances having a blowing function such as an air purifier and an air conditioner.

  10 Centrifugal fan, 12, 12A, 12B, 12C Impeller, 13 Outer frame, 13a, 13b End face, 14 Disc part, 16 Boss part, 21, 21A, 21B, 21C, 21D, 21E Fan blade, 23 Blade face, 24 Negative pressure surface, 25 positive pressure surface, 26 inner edge portion, 27 outer edge portion, 32, 62, 63, 67, 68, 262 vortex, 41, 41A, 41B bent portion, 51, 51p, 51q, 52, 52p, 52q convex portion, 56, 57, 57p, 57q Recessed part, 100 Cross-flow fan, 101 Center axis, 106 Center line, 110 Mold for molding, 112 Movable side mold, 114 Fixed side mold, 116 Cavity, 120, 150, 215 Blower, 126 Outer casing, 127, 154 Outlet, 128, 151 Drive motor, 129, 152, 222 Case 129a, 152a Guide wall, 130, 153 Suction part, 131 Inner peripheral side space, 132 Outer peripheral side space, 140 Air cleaner, 141 Filter, 142, 224 Suction port, 143, 225 Outlet, 144 Housing, 144a Rear Wall, 144b Top wall, 145 Duct, 210 Air conditioner, 220 Indoor unit, 222A, 222B Cabinet, 226 Air passage, 228 Air filter, 229 Indoor heat exchanger, 231 Horizontal louver, 232 Vertical louver, 241 Upstream area 242 downstream region, 246 upstream outer space, 247 inner space, 248 downstream outer space, 251 front wall portion, 252 rear wall portion, 253, 254 protruding portion, 256 upper guide portion, 257 lower guide portion.

Claims (14)

It has an inner edge part arranged on the inner peripheral side and an outer edge part arranged on the outer peripheral side, and includes a plurality of blade parts arranged at intervals in the circumferential direction,
The blade portion includes a pressure surface that extends between the inner edge portion and the outer edge portion and is disposed on the rotational direction side of the fan, and a suction surface disposed on the back side of the pressure surface. A surface is formed,
As the fan rotates, a fluid flow that flows between the inner edge and the outer edge occurs on the blade surface,
The blade portion has a blade cross section in which a concave portion is formed in the pressure surface and the suction surface when cut by a plane perpendicular to the rotation axis of the fan,
The plurality of blade portions include a first blade portion and a second blade portion having blade sections having different shapes from each other.   The fan according to claim 1, wherein the first blade portion and the second blade portion are different from each other in a position where the concave portion is formed.   The fan according to claim 1 or 2, wherein the first blade portion and the second blade portion are different from each other in the number of the recessed portions formed.   The fan according to any one of claims 1 to 3, wherein the first blade portion and the second blade portion are different from each other in shape of the concave portion.   5. The plurality of blade portions are arranged so that angles formed by lines connecting a rotation axis of a fan and the outer edge portion are equal between adjacent blade portions. Fans.   The plurality of blade portions are arranged so that angles formed by lines connecting a rotation axis of a fan and a centroid of a blade section of the blade portion are equal between adjacent blade portions. The fan according to any one of the above.   The fan according to any one of claims 1 to 6, wherein the plurality of types of blade portions having blade cross-sections having different shapes are arranged in an irregular order.   The concave portion formed on the pressure surface forms a convex portion on the negative pressure surface, and the concave portion formed on the negative pressure surface forms a convex portion on the pressure surface. The fan according to item 1.   The fan according to any one of claims 1 to 8, wherein the blade portion has a blade cross section having a constant thickness between the inner edge portion and the outer edge portion. The blade portion has a bent portion formed by bending a center line of a blade cross section between the pressure surface and the suction surface at a plurality of locations,
The fan according to claim 1, wherein the concave portion is formed by the bent portion. An inner space is formed inside the plurality of blade portions arranged in the circumferential direction, and an outer space is formed outside thereof,
The fan according to any one of claims 1 to 10, wherein the fan is a centrifugal fan that sends a fluid from the inner space to the outer space. An inner space is formed inside the plurality of blade portions arranged in the circumferential direction, and an outer space is formed outside thereof,
When viewed from the direction of the rotation axis of the fan, fluid is taken into the inner space from the outer space on one side with respect to the rotation axis, and the taken-in fluid is sent out to the outer space on the other side with respect to the rotation axis. The fan according to any one of claims 1 to 10, which is a cross-flow fan. The fan according to any one of claims 1 to 12, is formed of a resin,
Mold for molding, used to mold the fan.   A fluid feeder comprising: the fan according to any one of claims 1 to 12; and a blower configured to be connected to the fan and drive motors that rotate the plurality of blade portions.

Images