JP2018145938A - Propeller fan and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a propeller fan capable of improving a blast efficiency by making a rational flow of an air flow at a blade surface while restricting occurrence of either a blade tip vortex or a rear flow vortex.SOLUTION: A downstream end part of said blade is provided with several recesses that are recessed at an upstream side, contours of said recesses are constituted at least by an inner peripheral side contour line and an outer peripheral side contour line as seen from a direction of a revolving shaft of said propeller fan. When a virtual line defined to have an equal distance from said inner peripheral side contour line and said outer peripheral contour line is defined as a reference line in a direction of the recess, a virtual line connecting an outer peripheral lower-most downstream end at the downstream end part of said blade with said revolving shaft is defined as a reference line in a radial direction, an angle formed by said recess part side of the reference line in said recess direction and said revolving shaft side of said reference line in a radial direction is defined as an angle in a recess direction and a vertical distance from a crossing point with the contour of said recess part to said reference line in the radial direction is defined as a recess depth, the deepest recess of said several recesses has a smaller angle in a recess direction than 90 degrees.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a propeller fan used in, for example, an air conditioner.

  A conventional propeller fan having a plurality of blades attached to the outer peripheral surface of a cylindrical hub at predetermined intervals in the circumferential direction has a recess notched to the upstream side at the downstream end of the blade. There is something to have.

  The propeller fan rotates about the rotation axis to push out air on the blade surface. At this time, one of the blade surfaces pushes air, so that the pressure increases and the back surface of the blade is in a reduced pressure state. When the air flowing along the surface of the blade reaches the outer peripheral edge of the blade or the downstream end of the blade and leaves the blade surface, it forms a vortex by forming a flow that is engulfed from a high pressure surface to a low surface. The vortex generated on the outer peripheral side of the wing is called a tip vortex, and the vortex generated at the downstream end of the wing is called a wake vortex. Further, when the inlet separation that occurs at the upstream end of the blade and the blade surface disturbance that occurs on the surface of the blade reach the outer periphery of the blade or the downstream end of the blade, larger vortices and disturbance occur. These vortices and turbulence in the air flow have been factors that deteriorate the blowing efficiency of the propeller fan.

  In order to solve the problems caused by the blade tip vortex and the wake vortex, there are some in which a plurality of concave portions having the same shape are continuously provided at the downstream end portion of the propeller fan. These multiple recesses gradually reduce the wake vortex generated at the downstream end so that the air flowing along the pressure surface of the blade and the air flowing along the negative pressure surface are gradually merged. (For example, refer to Patent Document 1).

  However, the propeller fan described in Patent Document 1 can reduce the turbulence of the blade surface flow and the wake vortex generated at the downstream end, but the technical problem that the blade tip vortex generated at the outer peripheral end of the blade cannot be suppressed. is there. In addition, the air flow on the blade surface greatly varies depending on the radius of the propeller fan, and not only the flow velocity but also the flow direction varies depending on the location. For this reason, in the configuration in which the concave portions having the same shape are continuously arranged in the radial direction, even if the concave portion is effective at one radial position, it may have an adverse effect at another different radial position, and the efficiency is greatly improved as a whole. There is also a technical problem of not.

  Patent Document 2 proposes a propeller fan in which one arcuate or trapezoidal concave portion is provided at the downstream end of the blade.

  However, it is difficult to obtain an effect of sufficiently suppressing the turbulence of the airflow in the entire blade by providing only one concave portion having a simple shape such as an arc shape or a trapezoidal shape. In order to obtain a suppression effect with a single recess, for example, it is necessary to form a large recess on the entire downstream end of the blade. Even if the generated wake vortex can be suppressed, there is a problem that the flow of the entire blade surface changes secondary and a new turbulence occurs.

  Furthermore, in patent document 3, the recessed part formed in the curved line is provided in two or more places in the downstream end part of the propeller fan, and the depth of cut to the upstream side of the recessed part located on the outer peripheral side rather than the recessed part on the inner peripheral side It has been proposed to increase the size. As described above, the turbulence of the air flow can be further suppressed by setting the sizes of the plurality of concave portions according to the radial positions at the downstream end portions. In particular, the concave portion provided on the outer peripheral side can exert an effect not only on the wake vortex but also on the suppression of the blade tip vortex, so that the turbulence of the air flow due to the vortex can be further suppressed by increasing the concave portion on the outer peripheral side. . However, since the air on the blade surface is attracted in the radial direction of the propeller fan when the recessed portion is formed, the air on the blade surface is attracted to the recessed portion. For this reason, if the depth of cut of the concave portion on the outer peripheral side is increased, the air flow on the blade surface becomes a flow toward the outer peripheral side of the blade, and air flows on the inner peripheral side of the blade, particularly in the vicinity of the hub. It becomes difficult to flow. In this way, it becomes difficult for the air flow to flow uniformly over the entire blade surface, so that a new vortex is generated or a back flow of air occurs from the downstream direction of the rotating shaft, resulting in turbulence and reduced efficiency. There is a problem of doing.

Japanese Patent No. 3448136 Japanese Patent Laid-Open No. 2002-257088 Japanese Patent No. 2016-166600

  Therefore, the present invention has been made in view of the above-described problems, and suppresses the generation of blade tip vortices and wake vortices, while making the air flow on the blade surface ideal and improving the blowing efficiency. An object is to provide a propeller fan that can be improved.

  That is, the propeller fan according to the present invention is a propeller fan including a plurality of blades attached to the outer peripheral surface of the cylindrical hub at predetermined intervals in the circumferential direction, and the downstream end portion of the blade is A plurality of recesses cut away to the upstream side, and when viewed from the direction of the rotation axis of the propeller fan, the contour of the recess is at least composed of an inner peripheral contour line and an outer peripheral contour line, An imaginary line defined to be equidistant from the inner peripheral side contour line and the outer peripheral side contour line is a cutting direction reference line, and a virtual line that connects the outer peripheral end and the rotation axis at the downstream end of the wing. The radial reference line from the intersection of the radial reference line, the cut direction angle that is the angle formed by the concave side of the cut direction reference line and the rotational axis side of the radial reference line, and the contour of the concave portion When the vertical distance to the depth of cut is The largest recess cut depth of the concave portion of the number, the cutting direction angle, characterized in that it is made smaller than 90 degrees.

  In such a case, the merging of the air flowing along the pressure surface of the blade at the downstream end and the air flowing along the negative pressure surface of the blade is gradually caused by the plurality of concave portions formed in the downstream end of the blade. As a result, wake vortices are reduced. Moreover, generation | occurrence | production of the blade tip vortex which generate | occur | produces in an outer peripheral end can also be reduced by the recessed part provided in an outer peripheral side. Further, since the recess having the largest depth of cut among the plurality of recesses is configured to have a notch angle smaller than 90 °, the air flow on the blade surface is drawn toward the recess toward the outer peripheral side. In addition, air can be collected in an area where convergence is fast and air blowing efficiency can be improved. In addition, since the air flow is drawn in the concave portion on the inner peripheral side other than the largest concave portion, the air flow also flows in the vicinity of the hub so that the air flow is uniformly generated over the entire blade surface. Can be. From these facts, it is possible to prevent the efficiency from decreasing due to generation of a new vortex on the blade surface by forming the recess while suppressing the generation of the blade tip vortex and the wake vortex.

In order to make it easy for air to flow in the vicinity of the hub on the blade surface so as to increase the air blowing efficiency, a plurality of the concave portions are provided with an outer main concave portion having the largest depth of cut and formed on the outer peripheral side. An inner main recess that is formed on the inner circumferential side of the outer main recess and has the second largest cutting depth, and the angle of the outer main recess in the cutting direction is α _out , What is necessary is just to be comprised so that it may be set to (alpha) _in > (alpha) _out when a cutting direction angle is set to (alpha) _in .

In order for the outer main concave portion and the inner main concave portion to act on the same amount of air flow on the outer peripheral side and inner peripheral side of the blade, respectively, so that a uniform flow can be realized over the entire blade surface, The radius from the rotation axis to the intersection of the cut direction reference line and the radial reference line is a cut position radius, the cut position radius of the outer main recess is R _out , and the cut position of the inner main recess is When the radius is R _in and the area center diameter of the propeller fan is R _c , R _out > R c> R _in may be satisfied.

  In order to sufficiently exert the effect of suppressing the wing tip vortex by the outer main concave portion and to sufficiently exhibit the effect of forming an air flow in the vicinity of the hub by the inner main concave portion. Air flow by the inner main recess The outer main recess is formed on the outermost side of the plurality of recesses, and the inner main recess is formed on the innermost side of the plurality of recesses. That's fine.

The action of attracting air to the outer peripheral side by the outer main concave portion at the radially central portion of the wing and the action of attracting air to the inner peripheral side by the inner main concave portion are offset so that the air does not become excessively biased to the outer peripheral side. In order to improve the air blowing efficiency, α _out which is the cut direction angle of the outer main concave portion and α _in which is the cut direction angle of the inner main concave portion are α _in > 90 °> α _out. What is necessary is just to be comprised so that it may satisfy | fill.

  In order to suppress the unstable flow that occurs when the effect of attracting the flow on the blade surface changes monotonously in the radial direction and the intermediate recesses attract each other, a plurality of the recesses include the outer main recess and the inner One or more intermediate recesses provided between the main recess and the intermediate recess are further provided, and the intermediate recess has a larger cutting position radius and an αm that is the cutting direction angle becomes smaller as it is positioned on the outer peripheral side. It suffices to be configured.

As a specific range of the radial direction position formed with the cutting direction of the outer main concave portion and the inner main concave portion capable of improving the blowing efficiency, the cutting direction angle of the outer main concave portion is α _out , The outer main recessed portion has a cutting position radius R _out , the inner main recessed portion has a cutting direction angle α _in , the inner main recessed portion has a cutting position radius R _in , the outer peripheral radius of the blade is R, and the hub when the radius was R _{hub of, 90 × (R out -R in} ) / (R-R hub)> (α in -α out)> 45 × (R out -R in) / (R-R hub) The thing comprised so that may be mentioned.

Further, as a numerical range in which optimization of the blowing efficiency can be realized, the cutting direction angle of the outer main recessed portion is α _out , the cutting depth L _out of the outer main recessed portion, and the cutting direction angle of the inner main recessed portion. With respect to α _in and the cut depth L _in of the inner main recess, 90 × (L _out −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out The thing comprised so that may be mentioned.

  If it is an air conditioning apparatus provided with the propeller fan which concerns on this invention, high air-conditioning efficiency can be implement | achieved, implement | achieving low noise.

  Thus, according to the propeller fan according to the present invention, while suppressing the generation of the blade tip vortex and the wake vortex by the concave portion, the effect of attracting the entire flow of the blade surface of each concave portion is caused to cancel, It is possible to increase the air blowing efficiency by allowing air to flow also in the vicinity of the hub.

The schematic diagram which shows the propeller fan which concerns on one Embodiment of this invention. The typical enlarged view which expanded the downstream end part of the wing | blade which concerns on the embodiment. The typical enlarged view which showed the cutting direction angle of each recessed part in the downstream end part of the blade | wing which concerns on the same embodiment. The typical enlarged view which showed the cutting position radius of each recessed part in the downstream end part of the wing | blade which concerns on the embodiment. The schematic diagram which shows the flow of the air on a blade surface in case there is no inner side recessed part in the embodiment. The schematic diagram which shows the flow of the air on the blade surface in the same embodiment. The typical graph shown about the relationship between the parameter which is a cutting direction angle in the same embodiment, a cutting position radius, and ventilation efficiency. The typical graph shown about the relationship between the parameter which consists of a cutting direction angle and the cutting depth in the same embodiment, and ventilation efficiency. The schematic diagram which shows the propeller fan which concerns on another embodiment of this invention.

  A propeller fan 100 according to an embodiment of the present invention will be described with reference to the drawings.

  The propeller fan 100 of this embodiment is used, for example, in order to blow air to a heat exchanger in an outdoor unit of an air conditioner.

  As shown in FIG. 1, the propeller fan 100 includes a cylindrical hub 1 and three blades 2 provided at predetermined intervals in the circumferential direction with respect to the outer peripheral surface of the hub 1. .

  The blade 2 is provided with a plurality of recesses cut out to the upstream side at the downstream end. As shown in FIG. 1, the concave portion includes the largest outer main concave portion 3 provided on the outer peripheral side of the wing 2, the second largest inner main concave portion 4 provided on the inner peripheral side of the wing 2, and the outer side. A plurality of intermediate recesses 5 provided between the main recess 3 and the inner main recess 4 are provided. The outer main concave portion 3, the inner main concave portion 4, and the intermediate concave portion 5 are formed as substantially triangular cutouts having apexes on the upstream side when viewed from the rotation axis C direction of the propeller fan 100. That is, the contour of the concave portion is defined by two straight lines, that is, an inner peripheral contour line and an outer peripheral contour line. In the following, in order to define the shape, position, size, and orientation of each recess, the cutting direction reference line, the radial reference line, the cutting direction angle, and the cutting depth shown in FIGS. The feature of the recess will be described based on the parameters described above.

  The cutting direction reference line is an imaginary line determined so as to be equidistant from the inner peripheral contour and the outer peripheral contour. In the present embodiment, each concave portion has a substantially triangular shape, and therefore corresponds to a bisector of an angle passing through the apex on the upstream side of each concave portion.

  The radial reference line is an imaginary line that connects the outermost downstream end of the downstream end of the blade 2 and the rotation axis C. A wake end in which the concave portion is not formed at the downstream end portion of the blade 2 is formed in a sector region within ± 5 ° centering on the rotation axis C with respect to the radial reference line. is there.

  The cut direction angle is an angle formed by the concave side of the cut direction reference line and the rotation axis C side of the radial reference line. In the present embodiment, the angle is defined with the counterclockwise rotation from the radial reference line as positive with the intersection of the cut direction reference line and the radial reference line as the origin.

  The depth of cut is a vertical distance from the intersection with the contour of the recess to the radial reference line. In the present embodiment, each concave portion is formed in a substantially triangular shape, so that it can be approximated by a general height dimension.

  Next, details of each recess and the relationship between the recesses will be described in detail.

The outer main concave portion 3 is disposed at the outermost peripheral side at the downstream end portion of the blade 2 and has the deepest cut depth. 2 to the outer main recess 3 is smaller alpha _out ≒ 70 than its cut direction angle to face the inner peripheral side is alpha _out is 90 ° the cutting direction in the blade 2, as shown in FIG. 4 It is set to degrees.

The inner main concave portion 4 is arranged on the innermost peripheral side at the downstream end portion of the blade 2 and is configured such that the cut depth is the second deepest. The inner main recess 4 is set at larger alpha _in ≒ 105 degrees than alpha _in a cutting direction angle to face the outer peripheral side thereof cut direction in blade 2 is 90 °. That is, the cutting direction angles of the outer main recess 3 and the inner main recess 4 are set so that the relationship of α _in > α _out is satisfied.

The intermediate recess 5 is three recesses provided between the outer main recess 3 and the inner main recess 4, and is formed smaller than the inner main recess 4. When the cutting direction angle of each intermediate recess 5 is set to α _m1 , α _m2 , and α _{m3 in} order from the inner peripheral side, α _in > α _m1 > α _m2 > α _m3 > α _out and the outer periphery The angle in the cutting direction becomes smaller as the intermediate concave portion 5 is arranged on the side. In this embodiment, only the cut direction angle of the outer main concave portion 3 is configured to be an acute angle, and the relationship of α _in > α _m1 > α _m2 > α _m3 >90> α _out is maintained.

The inner main recess 4 and the three intermediate recesses 5 are arranged on the inner peripheral side of the area center diameter Rc of the propeller fan 100, respectively. On the other hand, most of the outer main recess 3 is arranged outside the area center diameter Rc of the propeller fan 100. The area center diameter Rc of the propeller fan 100 is defined by πRc ^ 2 = (πR ^ 2-πR _hub ^ 2) / 2, and when the air velocity in the axial direction is considered to be constant, the area center diameter The air volume inside Rc and the air volume outside are the same. With this definition, a relationship of Rc> (R + R _hub ) / 2 is established with respect to a simple average radius calculated by the average of the blade outer radius R and the hub radius R _hub .

A cutting location radius R _out of the outer main recess 3, the cutting-in position the radius R _in the inner main recess 4, when the outer circumferential blade radius R and the hub radius R _hub, the outer as shown in FIG. 3 The radial positional relationship between the main recess 3 and the inner main recess 4 is 90 × (R _out −R _in ) / (R−R _hub )> (α _in −α _out )> 45 × (R _out −R _in ) / (R−R _hub ). In this embodiment, (R _out −R _in ) / (R−R _hub ) ≈0.56, so 90 × (R _out −R _in ) / (R−R _hub ) ≈50.4 degrees, 45 × (R _out −R _in ) / (R−R _hub ) ≈25.2 degrees, which satisfies the above condition.

Also the cutting depth L _out of the outer main recess 3, when a cutting depth L _in the inner main recess 4, and the outer main recess 3 as shown in FIG. 4 and the inner main recess 4 The relationship between them is configured to satisfy 90 × (L _out −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out . In this embodiment, (L _out −L _in ) / L _in ≈0.75, 90 × (L _out −L _in ) / L _in ≈67.5 degrees, and 45 × (L _out −L _in ) Since / L _in ≈33.8 °, the above condition is satisfied.

  The effect of this embodiment configured as above will be described.

  In the propeller fan 100 of the present embodiment, the outer main concave portion 3, the intermediate concave portion 5, and the inner main concave portion 4 are formed at the downstream end portion of the blade 2, so that the pressure surface of the blade 2 at the downstream end of the blade 2. The air flowing along the negative pressure surface and the air flowing along the negative pressure surface are gradually merged, and the wake vortex generated at the downstream end of the blade 2 can be reduced.

  Further, the outer main concave portion 3 has an effect of suppressing not only the rear end vortex but also the blade tip vortex generated at the outer peripheral end of the blade 2. In the outer peripheral side contour line forming the outer main concave portion 3, the flow forms a vortex in the direction opposite to the blade tip vortex, and the vortex can be attenuated by canceling out the blade tip vortex. Further, the reverse vortex generated in the outer peripheral contour line attracts the blade tip vortex to the blade suction surface, and the effect of preventing the blade tip vortex from being separated from the blade surface is also obtained.

  Furthermore, since the concave portion originally has a blade surface and has a shape in which a region to which pressure is applied is cut out, air can flow relatively more easily than other portions of the blade surface. For this reason, the flow on the blade surface is attracted to the recess. The effect of drawing this flow is deeper in the depth of cut and the radius of the cut position is larger, that is, the effect is greater in the concave portion on the outer peripheral side, and either the inner peripheral side or the outer peripheral side of the concave portion depending on the cut direction angle. It depends on whether to draw more air. More specifically, when the cutting direction angle is 90 degrees or more, it has a tendency to pull toward the inner peripheral side, and when the cutting direction angle is 90 degrees or less, it has an effect of pulling toward the outer peripheral side.

For this reason, the outer main concave portion 3 is formed mainly for the purpose of suppressing the blade tip vortex, and therefore extends to the upstream side so as to include a point where the blade tip vortex may be separated. It has a deep shape. Moreover, since the cut direction angle α _out of the outer main recess 3 is configured to be smaller than 90 degrees, the effect of attracting air to the outer peripheral side of the outer main recess 3 is exhibited. Therefore, air can flow on the outer peripheral side, which is the region where the peripheral speed is fast and the air can be blown most efficiently on the blade surface.

  By the way, as shown in FIG. 5, when the inner peripheral recess is not provided, the air flow on the blade surface is attracted only to the outer main recess 3 and becomes a flow toward the outer periphery. . As a result, as shown in FIG. 5, a region where air hardly flows is newly generated near the hub 1 on the blade surface. As a result, turbulence may occur due to the generation of new vortices or the occurrence of a backflow of air from the downstream direction of the rotation axis C.

On the other hand, in the present embodiment, the outer main concave portion 3 having the largest cutting depth is disposed on the outermost periphery side, and the inner main concave portion 4 having the second largest cutting depth is disposed on the innermost peripheral side. and which, cutting direction angle alpha _in the inner circumferential side main recess and cutting direction angle alpha _out of the outer main recess 3 is configured to maintain the relation of α _in> α _out. Since not only the outer main recess 3 but also the inner main recess 4 are formed in this way, the inner contour line in the outer main recess 3 has the effect of attracting the air flow as shown in FIG. The recess 4 can be offset by the effect of attracting the air flow, and the air flow can also flow in the vicinity of the hub.

The outer main recessed portion 3 has a cutting direction angle α _out of 90 degrees or less and pulls the air flow on the surface of the blade 2 to the outer peripheral side, and the inner main recessed portion 4 has a cutting direction angle α _in of 90 degrees or more. The air flow on the surface is pulled toward the inner peripheral side, and air receives a force in the opposite direction in the region between the outer main recess 3 and the inner main recess 4. For this reason, the air flow tends to become unstable in the region.

That is, when the intermediate recess 5 is not formed as shown in FIG. 6, the direction in which the air flow is attracted may be appropriately changed between the outer main recess 3 and the inner main recess 4. For this reason, when the balance of the flow on the wing surface is lost, the flow is temporarily attracted to one of the recesses, and it tries to return to the original intermediate state, which in turn causes a phenomenon of being greatly attracted to the other recess. Sometimes. In the present embodiment, since a plurality of intermediate recesses 5 are provided between the outer main recess 3 and the inner main recess 4, air flow between the outer main recess 3 and the inner main recess 4 is prevented. Even if the balance is lost, it is possible to prevent a phenomenon in which the flow on the blade surface is greatly attracted to one of the outer peripheral side and the inner peripheral side by being attracted to the intermediate recess 5. More specifically, the intermediate recess 5 provided between the inner main recess 4 and the outer main recess 3 is configured such that the cut direction angle α _m decreases as the cut position radius increases and is positioned on the outer peripheral side. By doing so, the instability of air flow in the region between the outer main recess 3 and the inner main recess 4 can be reduced.

  In addition, the effect of the outer main recess 3 and the inner main recess 4 attracting the flow on the blade surface varies depending on the cutting depth and the cutting position radius.

Regarding the insertion position radius, the cutting direction angle α _out and the cutting position radius R _out of the outer main recess 3, the cutting direction angle α _in and the cutting position radius R _{in of} the inner peripheral main recess, and the blade outer radius R _{90 × (R out -R in)} / (R-R hub)> (α in -α out)> 45 × (R out -R in) / (R-R hub) to be about a hub radius R _hub High efficiency can be obtained. FIG. 7 is a graph of a simulation result _in which the horizontal axis is (α _in −α _out ) / {(R _out −R _in ) / (R−R _hub )}, and the vertical axis is an effect of improving the air blowing efficiency.

As for the depth of cut, 90 × (cutting direction angle α _out and cutting depth L _out of the outer main recessed portion 3 and cutting direction angle α _in and cutting depth L _in of the inner peripheral main recessed portion are 90 × ( High efficiency can be obtained by setting L _out −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out . FIG. 8 is a graph in which the horizontal axis is (α _in −α _out ) / {(L _out −L _in ) / L _out } and the vertical axis is an effect of improving the air blowing efficiency.

  Both FIG. 7 and FIG. 8 have inflection points near 45 degrees and 90 degrees. This is not only a phenomenon in which the flow gradually changes when the difference in the cutting direction angle between the outer main concave portion 3 and the inner main concave portion 4 is changed, but the flow is deviated to one side or very unstable. This is because a transition phenomenon occurs in which the turbulence is greatly increased due to the situation.

In this embodiment, 90 × (R _out −R _in ) / (R−R _hub )> (α _in −α _out )> 45 × (R _out −R _in ) / (R−R _hub ) and 90 × Both (L _out −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out are satisfied at the same time, and the air blowing efficiency is high.

  Next, a propeller fan 100 according to another embodiment of the present invention will be described with reference to FIG.

  Compared with the above embodiment, the propeller fan 100 of this embodiment has a point that the shape of the outer main recess 3 is not a triangle but a trapezoid when viewed from the direction of the rotation axis C, and the inner main recess 4 is The difference is that it is formed at the second position from the inner peripheral side, and the depth of cut is deeper in the inner main recess 4 than in the outer main recess 3.

  As shown in FIG. 9, the cutting direction reference line of the outer main recess 3 is a virtual line drawn so as to be equidistant from the inner contour line and the outer contour line. In other words, the virtual line can also be said to be a straight line passing through the midpoint of the upper base and the midpoint of the lower base of the trapezoid. Further, the depth of cut of the outer main concave portion 3 is defined in the same manner as in the above embodiment, but it can be said that it is a perpendicular drawn from the midpoint of the upper base to the lower base.

Also in this embodiment, when the cutting direction angle of the trapezoidal outer main concave portion 3 is α _out and the cutting direction angle of the triangular inner main concave portion 4 is α _in , the relationship of α _in > α _out is satisfied. As described above, the cutting direction angles of the outer main recess 3 and the inner main recess 4 are set.

  Also in this embodiment, substantially the same effect as in the previous embodiment can be obtained, and the air blowing efficiency can be improved. Further, by changing the position, number, and arrangement of the trapezoidal or triangular recesses, the trailing edge vortex can be changed according to the operating conditions of the propeller fan 100 or the influence of the flow of the blade surface due to obstacles at the entrance and exit. It can be made appropriate by changing the suppression effect.

  Other embodiments will be described.

  About the number of recessed parts, it can set suitably. For example, the blade may be configured such that only the outer main concave portion is provided at the downstream end portion of the blade and the cut direction angle is smaller than 90 °.

Further, the relationship between the cutting position radius and the cutting depth between the outer main concave portion and the inner main concave portion is not limited to that shown in each embodiment. For example, 90 × (R _out −R _in ) / (R−R _hub )> (α _in −α _out )> 45 × (R _out −R _in ) / (R−R _hub ), or 90 × (L _out A plurality of concave portions may be formed so as to satisfy only one of −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out .

  The contour line of the recess is not limited to a straight line, but may be a curved line. In this case, the cutting direction reference line can be defined by a curve, but the cutting direction angle can be defined by defining a tangent or the like of the cutting direction reference line at the intersection with the radial direction reference line. Using such parameters, the sizes and positional relationships of the plurality of recesses may satisfy the relationship as shown in the embodiment.

  The propeller fan according to the present invention may be used not only in the air conditioner but also in other devices.

  In addition, various combinations and modifications of the embodiments may be performed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Propeller fan 1 ... Hub 2 ... Blade 3 ... Outer main recessed part 4 ... Inner main recessed part 5 ... Intermediate recessed part

Claims (9)

A propeller fan comprising a plurality of blades attached at predetermined intervals in the circumferential direction to the outer peripheral surface of a cylindrical hub,
The downstream end of the wing includes a plurality of recesses cut away to the upstream side,
When viewed from the direction of the rotation axis of the propeller fan, the contour of the recess is at least composed of an inner peripheral contour and an outer peripheral contour,
An imaginary line defined to be equidistant from the inner peripheral contour line and the outer peripheral contour line is a cutting direction reference line, and an imaginary line connecting the outermost downstream end at the downstream end portion of the blade and the rotation axis. A radial reference line, a cut direction angle that is an angle formed by the concave side of the cut direction reference line and the rotation axis side of the radial reference line, and a radial direction from an intersection of the contour of the concave portion When the vertical distance to the reference line is the depth of cut,
A propeller fan characterized in that a recess having the largest depth of cut among the plurality of recesses is configured such that the angle in the cut direction is smaller than 90 degrees. A plurality of the recesses,
An outer main concave portion having the largest depth of cut formed on the outer peripheral side, an inner main concave portion formed on the inner peripheral side of the outer main concave portion and having the second largest depth of cut,
The _out the cutting direction angle of the outer main recess _alpha, when the cutting direction angle of the inner main recess and alpha _in, propeller fan alpha _in> alpha _out to become so Configured claim 1. The radius from the rotation axis to the intersection of the cut direction reference line and the radial reference line is a cut position radius, the cut position radius of the outer main recess is R _out , and the cut position of the inner main recess is When the radius is R _in and the area center diameter of the propeller fan is Rc,
The propeller fan according to claim 2, wherein R _out >Rc> R _in . The outer main concave portion is formed on the outermost peripheral side among the plurality of concave portions,
The propeller fan according to claim 2 or 3, wherein the inner main concave portion is formed on the innermost peripheral side among the plurality of concave portions. 5. Any one of claims 2 to 4, wherein α _out which is a cutting direction angle of the outer main recessed portion and α _in which is a cutting direction angle of the inner main recessed portion satisfy α _in > 90 °> α _out. The propeller fan described in Crab. A plurality of the recesses,
One or more intermediate recesses provided between the outer main recess and the inner main recess,
The propeller fan according to any one of claims 2 to 5, wherein the intermediate recess is configured such that αm, which is the angle in the cutting direction, decreases as the cutting position radius increases and is positioned on the outer peripheral side. The cut direction angle of the outer main recess is α _out , the cut position radius of the outer main recess is R _out , the cut direction angle of the inner main recess is α _in , and the cut position radius of the inner main recess is R _in , when the outer radius of the wing is R and the radius of the _hub is R _hub ,
Claims configured to satisfy 90 × (R _out −R _in ) / (R−R _hub )> (α _in −α _out )> 45 × (R _out −R _in ) / (R−R _hub ) The propeller fan according to any one of 2 to 6. The cut direction angle of the outer main recess is α _out , the cut depth L _out of the outer main recess, the cut direction angle of the inner main recess is α _in , and the cut depth L _in of the inner main recess. 8 is configured so that 90 × (L _out −L _in ) / L _out > (α _in −α _out )> 45 × (L _out −L _in ) / L _out . Propeller fan.   An air conditioner comprising the propeller fan according to any one of claims 1 to 8.