JPWO2019035153A1 - Impeller, blower, and air conditioner - Google Patents

Abstract

An impeller according to the present invention includes a boss portion that rotates about a rotation axis, and a plurality of blades provided on an outer peripheral wall of the boss portion and that rotates with the boss portion about the rotation axis. . The plurality of blades differ in the ratio of the chord length to the distance from the rotation axis, the angle between the rotation axis and the chord line, and the like according to the distance from the rotation axis. The impeller according to the present invention is provided with a plurality of blades having such a configuration, so that the impeller has lower noise and higher efficiency than before.

Description

  The present invention relates to an impeller that suppresses noise and improves efficiency, a blower that includes the impeller, and an air conditioner that includes the impeller.

  Conventionally, an axial blower is mounted and used inside a device such as a heat pump type air conditioner or a pressure ventilation fan. These devices have different internal ventilation resistances depending on the installation environment and operating conditions. In addition, due to adhesion of dust and the like to the heat exchanger and high-density mounting of components inside the apparatus, the axial flow fan mounted on the apparatus is required to cope with high static pressure. That is, in order to increase the static pressure, it is necessary to increase the rotational speed of the impeller of the axial blower. However, when the impeller of the conventional axial flow fan is rotated at high speed, noise increases due to the vortex generated at the peripheral edge of the blade, and the efficiency also decreases.

  In view of this, a conventional axial blower has been proposed in which noise is suppressed and efficiency is improved (see, for example, Patent Document 1). The impeller of the axial-flow fan described in Patent Document 1 has a plurality of blades provided on the outer peripheral wall of a boss portion (hub). The cross-sectional shape along the rotation direction of the blade has three or more alternately bulging portions that bulge toward the suction surface side of the blade and bulge portions that bulge toward the pressure surface side of the blade. In addition, a line that equally divides the bulging portion that bulges to the suction surface side and the bulging portion that bulges to the pressure surface side is a neutral line of the wing, and the bulging portion that bulges to the suction surface side and the pressure surface side The bulging portion that bulges is formed such that the distance from the neutral line of the wing increases from the leading edge of the wing toward the trailing edge of the wing.

JP 2010-150945 A

  An impeller of an axial blower includes a boss portion that rotates around a rotation shaft, and a plurality of blades that are provided on an outer peripheral wall of the boss portion and rotate around the rotation shaft together with the boss portion. For this reason, for example, the airflow before flowing between the wings flowing around the boss portion includes vortices generated when air passes around the boss portion. Further, for example, the airflow before flowing between the wings flowing around the boss portion includes a local high-speed flow that is generated when the boss portion and the above-described vortex are present in the flow path narrowed. Therefore, the airflow before flowing between the wings flowing around the boss portion is disturbed.

  Here, the conventional axial blower including the axial blower described in Patent Document 1 is not considered at all for the airflow flowing around the boss portion. For this reason, the conventional axial blower has a problem that noise increases when each blade pushes a turbulent airflow around the boss portion. Further, in the conventional blower, when each blade pushes the turbulent airflow around the boss portion to the blowing side, the separation of the flow occurs on the front edge portion side on the pressure surface of each blade. This peeling also increases noise. In addition, this peeling also reduces the efficiency. Moreover, in the conventional blower, the static pressure difference is large between the inner peripheral side portion of the blade that pushes the turbulent air flow and the outer peripheral side portion of the blade that pushes the undisturbed air flow. For this reason, a secondary flow that is a flow in a direction different from the intended flow direction is likely to occur on the pressure surface of each blade of the conventional blower due to the difference in static pressure. Therefore, the conventional blower has a problem that the efficiency is also lowered due to the turbulent airflow around the boss portion.

  The present invention has been made to solve the above-described problems, and has as its first object to obtain an impeller with lower noise and higher efficiency than conventional ones. Moreover, this invention sets it as the 2nd objective to obtain the air blower and air conditioning apparatus provided with such an impeller.

  An impeller according to the present invention includes a boss portion that rotates about a rotation shaft, and a plurality of blades that are provided on an outer peripheral wall of the boss portion and rotate about the rotation shaft together with the boss portion, Each of the wings is a front edge that is a front edge in the rotation direction of the wings, a rear edge that is a rear edge in the rotation direction, and an outer periphery that is an outer edge. A circle having a radius R centered on the rotation axis is defined as a virtual circle, and the boss part and the wing are arranged on a plane perpendicular to the rotation axis. In the projected shape, the intersection of the front edge and the virtual circle is a first intersection, the intersection of the rear edge and the virtual circle is a second intersection, and the second intersection from the first intersection in the same wing. The length of the arc of the virtual circle to the intersection is the first blade length L1, and the blade adjacent to the blade from the first intersection of any blade When the length of the arc of the virtual circle up to the first intersection is defined as the inter-blade distance t and the projection distance ratio σ is σ = L1 / t, the projection distance ratio σ is calculated from the inner periphery to the radius. R decreases to a position where the radius is RA, and the radius R has a first minimum value at a position where the radius R becomes the radius RA. From the position where the radius R becomes the radius RA, the radius R becomes smaller than the radius RA. From the position where the radius R becomes the radius RM from the position where the radius R is larger than the radius RM from the position where the radius R becomes the radius RM. The radius R decreases to a position where the radius RB is reached, the radius R has a second minimum value at the location where the radius RB becomes, and the radius R increases from the position where the radius RB becomes the radius to the outer peripheral portion; Before the intermediate position between the inner peripheral portion and the radius RA The radius R is the radius RC, the radius R is the intermediate position between the radius RA and the radius RM, the radius R is the radius RD, the radius R is the intermediate position between the radius RM and the radius RB, and the radius RE is the radius RB. The radius R, which is an intermediate position with respect to the outer peripheral portion, is a radius RF, the radius R is a value greater than the radius RD and less than the radius RD, the radius R is a radius RG, and the radius R is greater than the radius RE and less than the radius RF. Radius R is defined as radius RH, and in the meridional shape of the blade, the distance in the direction parallel to the rotation axis from the front edge portion to the rear edge portion at the position of radius R is defined as a second blade length L2. In this case, L2 / R, which is the ratio of the second blade length L2 to the radius R, increases from the inner peripheral portion to a position where the radius R becomes the radius RG, and the radius R becomes the radius RG. And the radius R is From the position where the radius R becomes the radius RH, the radius R decreases to the position where the radius R becomes the radius RH, and there is a local minimum value at the position where the radius R becomes the radius RH, and from the position where the radius R becomes the radius RH. It becomes the structure which increases toward the said outer peripheral part.

In the impeller according to the present invention, the portion around the boss portion of each blade has a shape that requires less work than in the prior art. In other words, in the impeller according to the present invention, the portion around the boss portion of each blade has a smaller amount of air to be pushed out than before. For this reason, the impeller which concerns on this invention can suppress the noise at the time of each blade pushing out the turbulent airflow around a boss | hub part compared with the past. Further, in the impeller according to the present invention, the work amount of the portion around the boss portion in each blade is smaller than that of the conventional art, and therefore noise caused by the separation of the flow generated on the pressure surface can be suppressed as compared with the conventional art. Further, in the impeller according to the present invention, since the work amount in the vicinity of the boss portion of each blade is smaller than that in the conventional art, it is possible to suppress the decrease in efficiency due to the separation of the flow generated on the pressure surface. Further, in the impeller according to the present invention, a turbulent airflow around the boss portion is guided to the outer peripheral side, and a large amount of less turbulent air flows toward the outer peripheral side by this airflow. And each wing | blade of the impeller which concerns on this invention becomes a shape where the work amount of the area | region where this air with little disturbance flows increases. For this reason, the impeller which concerns on this invention can improve efficiency. Further, on the pressure surface of each blade of the impeller according to the present invention, the static pressure difference between the inner peripheral side and the outer peripheral side becomes smaller than that in the past. For this reason, the impeller which concerns on this invention can suppress a secondary flow conventionally.
Therefore, the impeller according to the present invention is an impeller with lower noise and higher efficiency than the conventional one.

It is a perspective view which shows an example of the axial blower which concerns on Embodiment 1 of this invention. It is the figure which projected the impeller of the axial-flow fan which concerns on Embodiment 1 of this invention on the plane perpendicular | vertical to the rotating shaft of this impeller. It is the figure which projected the impeller of the axial-flow fan which concerns on Embodiment 1 of this invention on the plane perpendicular | vertical to the rotating shaft of this impeller. It is a figure which shows one meridian surface shape of the blade | wing of the impeller which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between projection distance ratio (sigma) and radius R in the wing | blade which concerns on Embodiment 1 of this invention. FIG. 6 is a diagram illustrating a relationship between a radius R and L2 / R, which is a ratio of a second blade length L2 to a radius R, in the blade according to the first embodiment of the present invention. It is a perspective view which shows the impeller of the conventional axial blower. It is a figure for demonstrating the flow of the airflow of the peripheral part of a boss | hub part of the blade | wing of the impeller of the conventional axial blower. It is the figure which observed the impeller which concerns on Embodiment 1 of this invention from the suction surface side along the rotating shaft. It is the figure which observed the impeller which concerns on Embodiment 1 of this invention from the suction surface side along the rotating shaft. It is a figure which shows the relationship between projection distance ratio (sigma) and radius R in the wing | blade which concerns on Embodiment 1 of this invention. FIG. 6 is a diagram illustrating a relationship between a radius R and L2 / R, which is a ratio of a second blade length L2 to a radius R, in the blade according to the first embodiment of the present invention. It is a figure which shows the relationship between projection distance ratio (sigma) and radius R in the wing | blade which concerns on Embodiment 1 of this invention. It is a perspective view of the impeller which concerns on Embodiment 2 of this invention. It is the figure which observed the impeller which concerns on Embodiment 2 of this invention from the direction orthogonal to a rotating shaft. It is the figure which projected the impeller of the axial-flow fan which concerns on Embodiment 2 of this invention on the plane perpendicular | vertical to the rotating shaft of this impeller. It is a figure which shows the relationship between angle (phi) and the radius R in the blade | wing which concerns on Embodiment 2 of this invention. It is a figure which shows the relationship between angle (phi) and the radius R in the blade | wing which concerns on Embodiment 2 of this invention. It is a perspective view which shows the impeller of the conventional axial blower. It is a figure which shows the wind speed distribution of the blowing side of the axial flow fan which concerns on Embodiment 2 of this invention. It is a longitudinal cross-sectional view which shows an example of the air conditioning apparatus which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a perspective view showing an example of an axial blower according to Embodiment 1 of the present invention. Moreover, FIG. 2 is the figure which projected the impeller of the axial-flow fan which concerns on Embodiment 1 of this invention on the plane perpendicular | vertical to the rotating shaft of this impeller. 1 and 2 are views of the impeller 1 observed from the suction surface 16 side of the blade 10. Moreover, the white arrow shown in FIG. 1 has shown the flow direction of the whole air when the impeller 1 rotates. Moreover, the thick circular arc-shaped arrow shown in FIG.1 and FIG.2 has shown the rotation direction of the impeller 1. FIG. That is, the thick arc-shaped arrow shown in FIGS. 1 and 2 indicates the rotation direction of a boss portion 2 and a plurality of blades 10 to be described later constituting the impeller 1.

  The axial blower 100 according to the first embodiment includes a casing 20 and an impeller 1. A substantially cylindrical bell mouth 21 is formed in the casing 20. The impeller 1 is rotatably disposed on the inner peripheral side of the bell mouth 21. The impeller 1 is rotated by a motor (not shown) or the like attached to a boss portion 2 described later.

  The impeller 1 includes a boss portion 2 and a plurality of blades 10. The boss portion 2 has a substantially cylindrical shape and rotates around the rotation shaft 3. Each of the wings 10 is provided on the outer peripheral wall of the boss portion 2. Specifically, each of the blades 10 is disposed on the outer peripheral side of the boss portion 2 at equal angular intervals, and protrudes radially from the outer peripheral wall of the boss portion 2. More specifically, as shown in FIG. 2, each of the blades 10 protrudes from the outer peripheral wall of the boss portion 2 in an inclined direction toward the rotation direction of the blade 10 with respect to the radial direction of the virtual circle centering on the rotation axis. .

  Each of the blades 10 has a front edge portion 11, a rear edge portion 12, an outer peripheral portion 13, an inner peripheral portion 14, a positive pressure surface 15, and a negative pressure surface 16. The front edge portion 11 is a front edge portion in the rotational direction of the peripheral edge portion of the blade 10. The rear edge portion 12 is an edge portion on the rear side in the rotation direction in the peripheral edge portion of the wing 10. The outer peripheral part 13 is an edge part on the outer peripheral side in the peripheral part of the blade 10. The outer peripheral portion 13 is formed in a substantially circular arc shape that protrudes from the front end portion 13a that is the front end portion in the rotational direction to the rear end portion 13b that is the rear end portion in the rotational direction. In other words, the outer peripheral portion 13 has a substantially arc shape that protrudes in a direction away from the rotary shaft 3 from the front end portion 13a that is the front end portion in the rotation direction to the rear end portion 13b that is the rear end portion in the rotation direction. Is formed.

  The inner peripheral portion 14 is an inner peripheral edge portion of the peripheral edge portion of the blade 10. That is, the blade 10 is connected to the outer peripheral wall of the boss portion 2 at the inner peripheral portion 14. Therefore, the inner peripheral portion 14 has a shape corresponding to the outer peripheral wall of the boss portion 2. Specifically, the inner peripheral portion 14 is formed in a substantially arc shape that protrudes from the front end portion 14a that is the front end portion in the rotation direction to the rear end portion 14b that is the rear end portion in the rotation direction. ing. In other words, the inner circumferential portion 14 is a substantially circular shape that protrudes in a direction away from the rotary shaft 3 from the front end portion 14a that is the front end portion in the rotational direction to the rear end portion 14b that is the rear end portion in the rotational direction. It is formed in an arc shape.

  The positive pressure surface 15 is a surface on the front side in the rotational direction among the two surfaces of the blade 10. That is, the air is pushed by the positive pressure surface 15 as the blade 10 rotates. As described above, FIGS. 1 and 2 are views of the impeller 1 observed from the suction surface 16 side of the blade 10. The pressure surface 15 is a surface of the blade 10 opposite to the suction surface 16. For this reason, in FIG.1 and FIG.2, since the positive pressure surface 15 will be arrange | positioned on the paper surface back side, the positive pressure surface 15 is not illustrated. The negative pressure surface 16 is a surface on the rear side in the rotation direction among the two surfaces of the blade 10.

  Each of the wings 10 rotates around the rotation shaft 3 together with the boss portion 2. When the boss part 2 and the plurality of blades 10 are rotated about the rotary shaft 3, the overall air flow flowing through the axial blower 100 is as indicated by the white arrows shown in FIG. That is, air is sucked into the axial blower 100 from the front side in FIG. Then, air is blown out from the axial blower 100 along the rotary shaft 3 toward the back side of the sheet of FIG. 1 and 2 exemplify the impeller 1 having seven blades 10, the number of the blades 10 of the impeller 1 may of course be other than seven.

  Next, the detailed shape of the wing 10 will be described. First, when describing the detailed shape of the wing 10, each parameter indicating the shape of the wing 10 is defined as follows.

  FIG. 3 is a diagram in which the impeller of the axial blower according to Embodiment 1 of the present invention is projected onto a plane perpendicular to the rotation axis of the impeller. That is, FIG. 3 shows a shape in which each of the boss portion 2 and the blade 10 is projected on a plane perpendicular to the rotation shaft 3. Moreover, FIG. 4 is a figure which shows one meridian surface shape of the blade | wing of the impeller which concerns on Embodiment 1 of this invention. The meridional shape of the wing 10 shown in FIG. 4 is a projection obtained by rotating each position of the wing 10 about the rotation axis 3 with respect to a plane passing through the rotation axis 3 and parallel to the rotation axis 3. Shape.

As shown in FIG. 3, a circle having a radius R around the rotation axis 3 is defined as a virtual circle 30. The radius R changes in value. The intersection of the leading edge 11 of the wing 10 and the virtual circle 30 is defined as a first intersection 31. The intersection of the trailing edge 12 of the wing 10 and the virtual circle 30 is defined as a second intersection 32. The length of the arc of the virtual circle 30 from the first intersection 31 to the second intersection 32 in the same blade 10 is defined as a first blade length L1. The length of the arc of the virtual circle 30 from the first intersection 31 of any blade 10 to the first intersection 31 of the blade 10 adjacent to the blade 10 is defined as the inter-blade distance t. The projection distance ratio σ is defined as σ = L1 / t. Further, as shown in FIG. 4, in the meridional shape of the wing 10, the distance in the direction parallel to the rotation axis 3 from the front edge portion 11 to the rear edge portion 12 at the position of the radius R is defined as the second blade length L2. Define.
Thus, when each parameter which shows the shape of the wing | blade 10 is defined, the wing | blade 10 becomes the following shapes.

  FIG. 5 is a diagram showing the relationship between the projection distance ratio σ and the radius R in the wing according to Embodiment 1 of the present invention. FIG. 6 is a diagram showing the relationship between the radius R and L2 / R, which is the ratio of the second blade length L2 to the radius R, in the blade according to Embodiment 1 of the present invention. 5 and 6, the radius R is represented by a dimensionless number called a radius ratio. Specifically, in FIGS. 5 and 6, the radius R of the position of the inner peripheral portion 14 is “0.0”. Further, in FIGS. 5 and 6, the radius R of the position of the outer peripheral portion 13 is “1.0”.

  As shown in FIG. 5, the projection distance ratio σ decreases from the inner peripheral portion 14 to a position where the radius R becomes the radius RA. The projection distance ratio σ has a first minimum value at a position where the radius R becomes the radius RA. Further, the projection distance ratio σ increases from a position where the radius R becomes the radius RA to a position where the radius R becomes a radius RM larger than the radius RA. The projection distance ratio σ has a maximum value at a position where the radius R becomes the radius RM. Further, the projection distance ratio σ decreases from a position where the radius R becomes the radius RM to a position where the radius R becomes a radius RB larger than the radius RM. The projection distance ratio σ has the second minimum value at a position where the radius R becomes the radius RB. Further, the projection distance ratio σ increases from the position where the radius R becomes the radius RB to the outer peripheral portion 13.

  As shown in FIG. 6, L2 / R, which is the ratio of the second blade length L2 to the radius R, increases from the inner peripheral portion 14 to a position where the radius R becomes the radius RG. L2 / R has a maximum value at a position where the radius R becomes the radius RG. L2 / R decreases from a position where the radius R becomes the radius RG to a position where the radius R becomes the radius RH. L2 / R has a minimum value at a position where the radius R becomes the radius RH. L2 / R increases from the position where the radius R becomes the radius RH to the outer peripheral portion 13. Further, L2 / R is maximum at a position where the radius R is the radius RG, and is minimum at a position where the radius R is the radius RH.

  In FIG. 6, the radius RG is smaller than the radius RA. However, the value of the radius RG is not limited to this, and may be a value near the radius RA. Specifically, as shown in FIG. 6, a radius R that is an intermediate position between the inner peripheral portion 14 and the radius RA is defined as a radius RC. A radius R that is an intermediate position between the radius RA and the radius RM is defined as a radius RD. In this case, the radius RG may be a value not less than the radius RC and not more than the radius RD. In FIG. 6, the radius RH is smaller than the radius RB. However, the value of the radius RH is not limited to this, and may be a value near the radius RB. Specifically, as shown in FIG. 6, the radius R that is an intermediate position between the radius RM and the radius RB is defined as a radius RE. A radius R that is an intermediate position between the radius RB and the outer peripheral portion 13 is defined as a radius RF. In this case, the radius RH may be a value not less than the radius RE and not more than the radius RF.

Therefore, the blade 10 has the following shape from the inner peripheral portion 14 to the outer peripheral portion 13.
As shown in FIG. 5, the projection distance ratio σ decreases from the inner peripheral portion 14 to the radius RA. That is, the distance between the adjacent blades 10 increases from the inner peripheral portion 14 to the radius RA, but the ratio of the first blade length L1 to the radius R is substantially constant. That is, the ratio of the chord length to the radius R is substantially constant from the inner peripheral portion 14 to the radius RA. The chord length is the length of the chord line. The chord line is a straight line obtained by developing a cross-sectional view of the blade 10 in a cylindrical cross section centered on the rotation shaft 3 and connecting the leading edge portion 11 and the trailing edge portion 12.

  Here, in both the blades of the impeller of the conventional axial flow fan and the blade 10 according to the first embodiment, the chord length increases as the distance from the rotating shaft increases. That is, in the blades of the impeller of the conventional axial fan and the blade 10 according to the first embodiment, the chord length increases as the radius R increases. At this time, in the blades of the impeller of the conventional axial flow fan, the ratio of the chord length to the radius R increases as the radius R increases. In other words, the blade of the impeller of the conventional axial blower has a larger work ratio with respect to the radius R as the radius R increases. On the other hand, in the blade 10 according to the first embodiment, the ratio of the chord length to the radius R is substantially constant from the inner peripheral portion 14 to the radius RA. That is, in the blade 10 according to the first embodiment, the blade area in the region from the inner peripheral portion 14 to the radius RA is smaller than the blade of the impeller of the conventional axial blower. In other words, in the blade 10 according to the first embodiment, the work amount in the region from the inner peripheral portion 14 to the radius RA is smaller than that of the blade of the impeller of the conventional axial fan. The work amount is the amount by which the wing 10 pushes air.

  Further, as shown in FIG. 6, L2 / R increases from the inner peripheral portion 14 to a position where the radius RG is in the vicinity of the radius RA. In other words, the blade 10 gradually rises from the inner peripheral portion 14 to a position having the radius RG. And the distance between the adjacent wing | blades 10 becomes long. The region near the radius RG and the radius RA is a region where the ratio of the distance between the blades 10 to the radius R is the longest. In other words, the region near the radius RG is a region where (t−L1) / R is the largest. Note that the rising of the blade 10 indicates that the angle between the chord line of the blade 10 and the rotary shaft 3 is reduced.

  As shown in FIG. 6, L2 / R decreases from the radius RG to the radius RH. That is, the wing 10 gradually goes to sleep from the radius RG to the radius RH. For this reason, the ratio of the work amount to the radius R of the blade 10 decreases from the radius RG to the radius RH near the radius RB. Note that the fact that the wing 10 goes to sleep indicates that the angle between the chord line of the wing 10 and the rotary shaft 3 increases.

  On the other hand, as shown in FIG. 5, the projection distance ratio σ is maximized at the position of the radius RM between the radius RG and the radius RH. That is, at the position of the radius RM, the ratio of the distance between the blades 10 to the radius R is minimum, but the ratio of the first blade length L1 to the radius R is maximum. That is, the ratio of the chord length to the radius R is maximized at the position of the radius RM. In other words, in the region near the radius RM, the ratio of the blade area to the radius R is maximized. In other words, in the region near the radius RM, the ratio of the effective area to the radius R is maximized. That is, the area in the vicinity of the radius RM is an area where the work amount is large. The effective area in the region where the blade 10 is present indicates the area of the portion where the flow separation does not occur in the blade area of the pressure surface 15 in the region where the blade 10 is present.

  Further, as shown in FIG. 5, the projection distance ratio σ decreases from the radius RM to the radius RB near the radius RH. That is, the distance between the adjacent blades 10 increases from the radius RM to the radius RB, but the ratio of the first blade length L1 to the radius R is substantially constant. That is, the ratio of the chord length to the radius R is almost constant from the radius RM to the radius RB.

  As described above, in the blades of the impeller of the conventional axial flow fan, the ratio of the chord length to the radius R increases as the radius R increases. On the other hand, in the blade 10 according to the first embodiment, the ratio of the chord length to the radius R is substantially constant from the radius RM to the radius RB. In other words, the blade 10 according to the first embodiment has a blade area smaller than that of the conventional blade from the radius RM to the radius RB. For this reason, in the blade 10 according to the first embodiment, the ratio of the work amount to the radius R is substantially constant from the radius RM to the radius RB. In other words, in the blade 10 according to the first embodiment, when the radius R increases in the region from the radius RM to the radius RB, the amount of work increase is larger than that of the impeller blade of the conventional axial fan. small.

  Then, the effect | action and effect of the impeller 1 which concern on this Embodiment 1 are demonstrated. In order to facilitate understanding of the effect of the impeller 1 according to the first embodiment, first, the operation and effect of the impeller of the conventional axial blower will be described first. And after that, an effect | action and effect of the impeller 1 which concerns on this Embodiment 1 are demonstrated.

  FIG. 7 is a perspective view showing an impeller of a conventional axial fan. In addition, when explaining the impeller 101 of the conventional axial-flow fan, each constituent of the conventional impeller 101 includes the reference numerals of the constituents of the impeller 1 according to the first embodiment corresponding to these configurations. A reference numeral added with “100” is added. For example, the sign “110” is attached to the blades of the conventional impeller 101. Moreover, the white arrow shown in FIG. 7 has shown the flow direction of the whole air when the conventional impeller 101 rotates. Moreover, the thick line arrow shown in FIG. 7 has shown the rotation direction of the conventional impeller 101. FIG. In FIG. 7, some of the blades 110 among the plurality of blades 110 included in the conventional impeller 101 are not shown.

  When the conventional impeller 101 rotates around the rotation shaft 103, air is sucked into the impeller 101 from the upper side to the lower side in FIG. This air flows between the adjacent blades 110 from the front edge 111 side of the blade 110. When the air flowing between the blades 110 flows along the pressure surface 115 of the blades 110, the flow direction is changed by the inclination and warpage of the blades 110, and the static pressure increases due to the momentum change. At this time, the airflow 50 before flowing between the wings 110 flowing around the boss portion 102 is disturbed as shown in FIG.

  Specifically, the boss portion 102 exists on the inner peripheral side of the blade 110 at a position on the upstream side of the airflow flowing between the blades 110. For this reason, the airflow 50 before flowing into the space between the wings 110 flowing around the boss portion 102 includes vortices 51 generated when air passes around the boss portion 102. In addition, for example, the local high-speed flow generated when the airflow 50 before flowing between the blades 110 flowing around the boss portion 102 flows through the flow path narrowed by the presence of the boss portion 102 and the vortex 51 described above. 52 is also included. Therefore, the airflow 50 before flowing into the space between the wings 110 flowing around the boss portion 102 is disturbed. For this reason, in the conventional impeller 101, when the positive pressure surface 115 of each blade 110 pushes the turbulent airflow 50 around the boss portion 102, noise increases.

  Moreover, when the conventional impeller 101 extrudes the turbulent airflow 50 around the boss portion 102 by the inner peripheral side portion of each blade 110, the efficiency also decreases as follows.

  FIG. 8 is a view for explaining the flow of airflow around the boss portion of the impeller blades of a conventional axial fan. FIG. 8A is a view of the conventional impeller 101 observed in the direction of the rotation shaft 103. Moreover, FIG.8 (b) is AA sectional drawing of Fig.8 (a). In other words, FIG. 8B is a developed view of the AA position in the cylindrical cross section with the rotation shaft 103 as the center. In addition, the thick line arrow shown to Fig.8 (a) has shown the rotation direction of the conventional impeller 101. FIG.

  As described above, the airflow 50 before flowing into the space between the wings 110 flowing around the boss portion 102 is disturbed. For this reason, when the airflow 50 flows between the blades 110 from the front edge 111 side of the blade 110, the tangential direction 111a of the front edge 111 of the blade 110 and the direction of the airflow 50 do not match. For this reason, flow separation occurs on the front edge 111 side on the pressure surface 115 of the inner peripheral side portion of each blade 110. The separated flow is reattached to the pressure surface 115 near the attachment point 54 by the suction force of the vortex 53 generated on the front edge 111 side by the flow separation. The airflow after reattachment flows along the pressure surface and the static pressure rises. However, in the conventional impeller 101, the effective area of the blades 110 is reduced by the separation of the flow generated on the front edge 111 side of the pressure surface 115. For this reason, in the conventional impeller 101, the work of the blades 110 is reduced, and the efficiency is lowered. Further, in the conventional impeller 101, noise is also increased by separation of a flow generated on the front edge portion 111 side of the positive pressure surface 115.

  Further, in the airflow passing through the outer peripheral side portion of the blades 110 of the conventional impeller 101, there is no resistance portion that causes turbulence on the upstream side. For this reason, the static pressure tends to increase in the outer peripheral side portion of the blade 110 compared to the inner peripheral side portion of the blade 110. Moreover, since the moment is larger on the outer peripheral side of the blade 110 than on the inner peripheral side of the blade 110, the static pressure is increased. From these points, the conventional impeller 101 has a large static pressure difference between the inner peripheral portion and the outer peripheral portion of the blade 110. For this reason, a secondary flow that is a flow in a direction different from the intended flow direction is likely to occur on the pressure surface 115 of each blade 110 of the conventional impeller 101 due to the difference in static pressure. Therefore, the efficiency of the conventional impeller 101 is lowered even by this secondary flow.

  On the other hand, since the impeller 1 according to the first embodiment operates as described below, it can suppress noise caused by the airflow 50 and can suppress a decrease in efficiency caused by the airflow 50.

  9 and 10 are views of the impeller according to Embodiment 1 of the present invention observed from the suction surface side along the rotation axis. FIG. 9 is a view for explaining the airflow in the inner peripheral portion of the blade 10. FIG. 10 is a view for explaining the airflow in the outer peripheral portion of the blade 10.

  Similarly to the conventional impeller 101, the impeller 1 according to the first embodiment also has a boss portion 2. For this reason, also in the impeller 1 which concerns on this Embodiment 1, the airflow before flowing in between the blade | wings 10 which flow around the boss | hub part 2 turns into the turbulent airflow 50 similarly to the past. However, in the blade 10 of the impeller 1 according to the first embodiment, the region from the inner peripheral portion 14 to the radius RA has a smaller blade area and a smaller amount of work than the conventional one. In other words, in the blade 10 of the impeller 1 according to the first embodiment, the peripheral portion of the boss portion 2, that is, the inner peripheral side portion, has a smaller work amount than the conventional one. That is, in the impeller 1 according to the first embodiment, the portion around the boss portion 2 in each blade 10 has a smaller amount of pushing out air than in the past. For this reason, the impeller 1 which concerns on this Embodiment 1 can suppress the noise at the time of each blade 10 pushing out the turbulent airflow 50 around the boss | hub part 2 from the past. In other words, the impeller 1 according to the first embodiment can suppress the noise when each blade 10 passes through the turbulent airflow 50 around the boss portion 2 as compared with the conventional case.

  Further, in the impeller 1 according to the first embodiment, since the work amount of the portion around the boss portion 2 in each blade 10 is smaller than the conventional work, noise caused by separation of the flow generated on the pressure surface 15 is also reduced. It can be suppressed than before. Further, in the impeller 1 according to the first embodiment, since the work amount of the portion around the boss portion 2 in each blade 10 is smaller than that in the conventional art, the efficiency is reduced due to the separation of the flow generated on the pressure surface 15. Can be suppressed as compared with the prior art.

  Here, as described above, the blade 10 gradually rises from the inner peripheral portion 14 to a position where the radius RG is in the vicinity of the radius RA. In other words, when it is limited to the area around the boss portion 2 of the blade 10 that has a smaller amount of work than in the prior art, the amount of work increases toward the outer peripheral side. Therefore, the turbulent airflow 50 around the boss portion 2 is guided to the outer peripheral side. Further, as described above, the distance between the blades 10 is long in the region near the radius RG and the radius RA. For this reason, in the area | region of radius RG and radius RA, many airflows 55 with few disturbances flow between the blades 10. As shown in FIG. 9, the air flow 55 is guided to the outer peripheral side from the radius RG and the radius RA due to the influence of the air flow 50. That is, the air flow 55 flows toward the region near the radius RM in the blade 10. As described above, the area of the blade 10 near the radius RM has a large ratio of the blade area to the radius R. For this reason, since the impeller 1 which concerns on this Embodiment 1 can let many airflows 55 with little disturbance pass through the area | region of radius RM with a large work volume, efficiency improves.

  On the other hand, in the region on the outer peripheral side with respect to the radius RM, as shown in FIG. Here, as described above, the blade 10 according to the first embodiment has a greater work in the region from the radius RM to the radius RB than the blade of the impeller of the conventional axial fan when the radius R increases. The amount of increase is small. For example, in the blade 10 according to the first embodiment, the work amount to the airflow 56 is substantially constant from the radius RM to the radius RB. For this reason, in the positive pressure surface 15 of the wing | blade 10 which concerns on this Embodiment 1, the static pressure difference of an inner peripheral side and an outer peripheral side becomes smaller than before. For this reason, the impeller 1 which concerns on this Embodiment 1 can suppress a secondary flow compared with the past, and efficiency improves further.

  Therefore, the impeller 1 according to the first embodiment is an impeller with lower noise and higher efficiency than the conventional one.

  Finally, a description will be given of suitable ranges of the radius RA, the radius RM, the radius RB, the radius RG, the radius RH, the projection distance ratio σ at the radius RM, and the projection distance ratio σ at the radius RB.

  FIG. 11 is a diagram showing the relationship between the projection distance ratio σ and the radius R in the wing according to Embodiment 1 of the present invention. FIG. 11 is a diagram showing preferred ranges of the radius RA, the radius RM, and the radius RB. FIG. 12 is a diagram showing the relationship between the radius R and L2 / R, which is the ratio of the second blade length L2 to the radius R, in the blade according to the first embodiment of the present invention. FIG. 12 shows a preferable range of the radius RG and the radius RH. FIG. 13 is a diagram showing the relationship between the projection distance ratio σ and the radius R in the wing according to Embodiment 1 of the present invention. FIG. 13 is a diagram showing a preferable range of the projection distance ratio σ at the radius RM and the projection distance ratio σ at the radius RB. In addition, in FIGS. 11-13, the radius R is represented by the dimensionless number called a radius ratio. Specifically, in FIGS. 11 to 13, the radius R of the position of the inner peripheral portion 14 is “0.0”. 11 to 13, the radius R of the position of the outer peripheral portion 13 is “1.0”.

  Due to the pressure difference between the pressure surface 15 and the suction surface 16 of the blade 10, torque in the direction opposite to the rotation direction is applied to the impeller 1. This torque increases the power consumption of a motor (not shown) that rotates the impeller 1. The torque acting on the impeller 1 can be evaluated by the product of the radius R, which is a moment arm, and the area of the pressure difference in each part of the blade 10. For this reason, in order to reduce the torque acting on the impeller 1, it is effective to reduce the blade area in the outer peripheral side portion of the blade 10 where the radius R, which is a moment arm, becomes large. Here, in the blade 10 of the axial blower 100 according to the first embodiment, the blade area in the region near the radius RB is smaller than that of the conventional impeller. For this reason, if the position of radius RB is made into the position which becomes the outer peripheral side of the wing | blade 10, the torque which acts on the impeller 1 can be reduced. Therefore, as shown in FIG. 11, the radius RB is preferably within a range of 0.7 or more and 0.8 or less.

  On the other hand, if the area on the outer peripheral side of the blade 10 is simply made smaller than before, the work amount of the impeller 1 will be lower than before. For this reason, as shown in FIG. 11, it is preferable that the radius RM is within a range of 0.45 or more and 0.55 or less. In other words, it is preferable to arrange a region having a radius RM where the work amount becomes large at a position where the radius is within a range of 0.45 or more and 0.55 or less. By earning the work amount in the region of the radius RM, it is possible to reduce the torque acting on the impeller 1 while ensuring a constant work amount. Moreover, the impeller 1 reduces the noise when each blade 10 passes through the turbulent airflow 50 around the boss portion 2 by making the blade area in the region from the inner peripheral portion 14 to the radius RA smaller than the conventional one. Suppressed. As shown in FIG. 11, by setting the radius RA within the range of 0.2 or more and 0.3 or less, the noise when each blade 10 passes through the turbulent airflow 50 around the boss portion 2 is further reduced. Can be suppressed.

  The blade area of each blade 10 of the impeller 1 increases from the position of the radius RA to the radius RM that is on the outer peripheral side of the radius RA. Further, each blade 10 of the impeller 1 gradually goes to sleep from the radius RG to the radius RH. For this reason, as shown in FIG. 12, it is preferable that the radius RG is in the range of 0.15 or more and 0.25 or less, and the position of the radius RA is close to the position of the radius RG. By setting the radius RG within such a range, the ratio of work to the radius R can be made uniform. Further, the position of the radius RH is the position where the person lies most among the positions of the wing 10. That is, the region near the radius RH is a region where the pressure difference between the pressure surface 15 and the suction surface 16 is small. For this reason, as shown in FIG. 12, it is preferable that the radius RH is within the range of 0.7 to 0.8, and the position of the radius RB is close to the position of the radius RH. By setting the radius RH within such a range, the torque acting on the impeller 1 can be further suppressed.

  As shown in FIG. 13, the projection distance ratio σ at the radius RB is preferably set to 0.6 or more. As described above, the torque acting on the impeller 1 can be reduced by reducing the blade area at the position of the radius RB. Here, the size of the projection distance ratio σ can be regarded as the size of the blade area. Therefore, the torque acting on the impeller 1 can be reduced by reducing the projection distance ratio σ at the radius RB. However, if the projection distance ratio σ at the radius RB is too small, the work in the vicinity of the radius RB becomes too small. For this reason, the projection distance ratio σ at the radius RB is preferably 0.6 or more.

  Further, as shown in FIG. 13, the projection distance ratio σ at the radius RM is preferably 0.9 or more and less than 1.0. The region near the radius RM is a region that earns work. Therefore, the projection distance ratio σ at the radius RM is preferably 0.9 or more so that the blade area in the region near the radius RM becomes large. However, if the projection distance ratio σ is set to 1.0 or more, the first blade length L1 becomes larger than the inter-blade distance t. That is, when the impeller 1 is observed in the direction of the rotation axis 3, the rear edge portion 12 and the front edge portion 11 of the adjacent blades 10 overlap each other. When the adjacent blade | wing 10 has such a relationship, when it is going to manufacture the impeller 1 using a metal mold | die, a metal mold | die must be made into an undercut structure. For this reason, the projection distance ratio σ at the radius RM is preferably less than 1.0.

  As described above, the impeller 1 according to the first embodiment is provided on the boss portion 2 that rotates about the rotation shaft 3 and the outer peripheral wall of the rotation shaft 3, and the impeller 1 rotates around the rotation shaft 3 together with the rotation shaft 3. The wing 10 is provided. Each of the wings 10 includes a front edge portion 11, a rear edge portion 12, an outer peripheral portion 13, and an inner peripheral portion 14. Further, in each of the blades 10, the projection distance ratio σ is as follows. Specifically, the projection distance ratio σ decreases from the inner peripheral portion 14 to a position where the radius R becomes the radius RA. Further, the projection distance ratio σ has a first minimum value at a position where the radius R becomes the radius RA. Further, the projection distance ratio σ increases from a position where the radius R becomes the radius RA to a position where the radius R becomes a radius RM larger than the radius RA. The projection distance ratio σ has a maximum value at a position where the radius R becomes the radius RM. Further, the projection distance ratio σ decreases from a position where the radius R becomes the radius RM to a position where the radius R becomes a radius RB larger than the radius RM. Further, the projection distance ratio σ has a second minimum value at a position where the radius R becomes the radius RB. Further, the projection distance ratio σ increases from the position where the radius R becomes the radius RB to the outer peripheral portion 13. Further, in each of the blades 10, L2 / R that is the ratio of the second blade length L2 to the radius R is as follows. Specifically, L2 / R increases from the inner peripheral portion 14 to a position where the radius R becomes the radius RG. L2 / R has a maximum value at a position where the radius R becomes the radius RG. L2 / R decreases from a position where the radius R becomes the radius RG to a position where the radius R becomes the radius RH. L2 / R has a minimum value at a position where the radius R becomes the radius RH. L2 / R increases from the position where the radius R becomes the radius RH to the outer periphery.

  Since the impeller 1 according to the first embodiment is configured as described above, it is possible to suppress noise caused by the turbulent airflow 50 and to suppress a decrease in efficiency caused by the turbulent airflow 50. Therefore, the impeller 1 according to the first embodiment is an impeller with lower noise and higher efficiency than the conventional one.

Embodiment 2. FIG.
Next, the impeller 1 which concerns on Embodiment 2 of this invention is demonstrated. In the second embodiment, items not particularly described are the same as those in the first embodiment, and the same functions and configurations are described using the same reference numerals.

  FIG. 14 is a perspective view of an impeller according to Embodiment 2 of the present invention. FIG. 15 is a diagram of the impeller according to Embodiment 2 of the present invention observed from a direction orthogonal to the rotation axis. In addition, the white arrow shown in FIG.14 and FIG.15 has shown the flow direction of the whole air when the impeller 1 rotates. Moreover, the thick arrow shown in FIG. 14 and the arc-shaped arrow shown near the rotating shaft 3 in FIG. 15 indicate the rotation direction of the impeller 1. 14 and 15, some of the blades 10 included in the impeller 1 are not shown. FIG. 15 also shows a casing 20 in addition to the impeller 1. That is, FIG. 15 shows an axial blower 100 according to the second embodiment.

  As shown in FIGS. 14 and 15, each blade 10 of the impeller 1 according to the second embodiment has the positive pressure surface 15 in a different direction depending on the position. Hereinafter, the direction of the pressure surface 15 at each position of the blade 10 will be described in detail. First, in order to describe the direction of the pressure surface 15 at each position of the blade 10, an angle φ that is a parameter indicating the direction of the pressure surface 15 is defined as follows.

FIG. 16 is a diagram in which an impeller of an axial blower according to Embodiment 2 of the present invention is projected onto a plane perpendicular to the rotation axis of the impeller. FIG. 16 is a view of the impeller 1 observed from the suction surface 16 side of the blade 10.
At an arbitrary point B of the blade 10, the normal line of the pressure surface 15 is drawn. A projection of this normal on a plane perpendicular to the rotation axis 3 of the impeller 1 is a first virtual straight line 41. Further, a second virtual straight line 42 passing through the rotation shaft 3 and the point B is drawn on a plane perpendicular to the rotation shaft 3 of the impeller 1. Thereby, the four angles which the 1st virtual straight line 41 and the 2nd virtual straight line make can be made. Among these, two of the angles formed by the first imaginary straight line 41 and the second imaginary straight line can be made in front of the rotation direction with respect to the second imaginary straight line 42. Of these two angles that can be on the front side in the rotational direction with respect to the second virtual straight line 42, the angle closer to the rotation axis 3, in other words, the angle on the inner peripheral side is defined as the angle φ.

  When the angle φ is larger than approximately 90 degrees, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to be away from the rotation shaft 3. In other words, when the angle φ is larger than about 90 degrees, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotational direction so as to go to the outer peripheral side. That is, when the angle φ is larger than approximately 90 degrees, the positive pressure surface 15 faces the outer peripheral side. When the angle φ is smaller than approximately 90 degrees, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to approach the rotation shaft 3. In other words, when the angle φ is smaller than approximately 90 degrees, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotational direction so as to be directed inward. That is, when the angle φ is smaller than approximately 90 degrees, the positive pressure surface 15 is in an inward state.

  FIG. 17 is a diagram showing a relationship between the angle φ and the radius R in the blade according to the second embodiment of the present invention. In FIG. 17, the radius R is represented by a dimensionless number called a radius ratio. Specifically, in FIG. 17, the radius R of the position of the inner peripheral portion 14 is “0.0”. In FIG. 17, the radius R of the position of the outer peripheral portion 13 is “1.0”. In FIG. 17, the solid line indicates the relationship between the angle φ and the radius R at the front edge portion 11. A broken line indicates the relationship between the angle φ and the radius R at the trailing edge 12.

First, the relationship between the angle φ and the radius R at the leading edge 11 will be described.
As shown in FIG. 17, the angle φ is larger than 90 degrees in a part of the range including the inner peripheral portion 14 in the range where the radius R becomes the radius RA from the inner peripheral portion 14. That is, the normal line of the pressure surface 15 is away from the pressure surface 15 so as to be away from the rotating shaft 3 in a part of the range including the inner periphery portion 14 in the range where the radius R is the radius RA from the inner periphery portion 14. It extends in the direction of rotation. In other words, the positive pressure surface 15 faces the outer peripheral side in a part of the range including the inner peripheral portion 14 in the range where the radius R becomes the radius RA from the inner peripheral portion 14. Specifically, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to be away from the rotation shaft 3 in a range where the radius R is 0.0 or more and 0.15 or less.

  With this configuration, as shown in FIG. 15, the airflow 58 that flows in a part of the range including the inner peripheral portion 14 flows toward the outer peripheral side. As described in the first embodiment, the impeller 1 guides the turbulent airflow 50 around the boss portion 2 to the outer peripheral side. A large amount of airflow 55 with less turbulence is passed through a region near the radius RM where the work amount is large, and the efficiency of the impeller 1 is improved. As in the second embodiment, when the pressure surface 15 in a part of the range including the inner peripheral portion 14 faces the outer peripheral side, the turbulent airflow 50 around the boss portion 2 can be guided to the outer peripheral side. That is, it is possible to pass more airflow 55 with less turbulence through a region near the radius RM where the work amount is large. Therefore, the efficiency of the impeller 1 can be further improved.

  In the second embodiment, the positive pressure surface 15 faces the outer peripheral side in a part of the range including the inner peripheral portion 14 in the range where the radius R is the radius RA from the inner peripheral portion 14. However, as long as the turbulent airflow 50 around the boss portion 2 can be guided to the outer peripheral side, the range in which the positive pressure surface 15 faces the outer peripheral side is not limited to the range. For example, the positive pressure surface 15 may face the outer peripheral side in the entire range from the inner peripheral part 14 to the radius R being the radius RA. In other words, the normal line of the pressure surface 15 may extend from the pressure surface 15 in the rotational direction so as to be away from the rotation shaft 3 in the entire range where the radius R is the radius RA from the inner peripheral portion 14. That is, the normal line of the pressure surface 15 extends from the pressure surface 15 so as to be away from the rotating shaft 3 in at least a part of the range including the inner periphery portion 14 in the range where the radius R is the radius RA from the inner periphery portion 14. What is necessary is just to extend in the rotation direction.

  As shown in FIG. 17, the angle φ is smaller than 90 degrees at a position where the radius R becomes the radius RM. That is, at the position where the radius R becomes the radius RM, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to approach the rotation shaft 3. In other words, the pressure surface 15 faces inward around the position where the radius R becomes the radius RM. With this configuration, as shown in FIG. 15, the airflow 59 that flows around the position where the radius R becomes the radius RM flows toward the inside.

  Generally, in an impeller of an axial blower, the airflow flowing between the blades tends to flow to the outer peripheral side due to the influence of centrifugal force. For this reason, when the pressure surface 15 is directed inward around the position where the radius R becomes the radius RM, the work amount around the position where the radius RM of the blade 10 becomes the radius can be increased. In other words, the amount of increase in static pressure can be increased around the position where the radius RM is obtained. Here, as described in the first embodiment, the impeller 1 improves the efficiency of the impeller 1 by increasing the work amount around the position where the radius RM becomes. For this reason, the efficiency of the impeller 1 can be further improved by orienting the positive pressure surface 15 in the vicinity of the position where the radius R becomes the radius RM.

  Further, as shown in FIG. 17, in the range from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the angle φ is larger than 90 degrees. That is, in the range from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to be away from the rotation shaft 3. In other words, in the range from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the positive pressure surface 15 faces the outer peripheral side. Specifically, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to be away from the rotation shaft 3 in a range where the radius R is 0.75 or more and 1.0 or less. With this configuration, as shown in FIG. 15, the airflow 60 flowing from the position where the radius R becomes the radius RB to the outer peripheral portion 13 flows toward the outer peripheral side. For this reason, generation | occurrence | production of the blade tip vortex 57 can be suppressed in the outer peripheral part 13 vicinity of the blade 10. FIG. Details of the reason why generation of the blade tip vortex 57 can be suppressed will be described later.

  In the second embodiment, the positive pressure surface 15 faces the outer peripheral side in the entire range from the position where the radius R becomes the radius RB to the outer peripheral portion 13. However, even if the positive pressure surface 15 faces the outer peripheral side in a part of the range including the outer peripheral portion 13 from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the generation of the blade tip vortex 57 is suppressed. it can. That is, in the range from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the positive pressure surface 15 only needs to face the outer peripheral side in at least a part of the range including the outer peripheral portion 13. In other words, in the range from the position where the radius R becomes the radius RB to the outer peripheral portion 13, the normal line of the pressure surface 15 is the pressure surface so as to be away from the rotation shaft 3 in at least a part of the range including the outer peripheral portion 13. What is necessary is just to extend from 15 in the rotation direction.

Next, the relationship between the angle φ and the radius R at the trailing edge 12 will be described.
As described above, generally, in an impeller of an axial blower, the airflow flowing between the blades tends to flow to the outer peripheral side due to the influence of centrifugal force. For this reason, when the range which has faced the outer peripheral side in the positive pressure surface 15 increases too much, the work amount of the impeller 1 will fall. This is because when air is pushed by the blade 10 and a force is applied to the air, the air escapes to the outer peripheral side of the impeller 1 and the force applied to the air is reduced. Here, as can be seen with reference to FIG. 8, separation of the flow generated by the turbulent airflow 50 around the boss portion 2 occurs on the front edge portion 11 side of the blade 10. That is, the trailing edge 12 side of the blade 10 is less affected by the turbulent airflow 50 around the boss 2. Therefore, in the second embodiment, as shown in FIG. 17, the rear edge portion 12 of each blade 10 has an angle φ smaller than 90 degrees over the entire region from the inner peripheral portion 14 to the outer peripheral portion 13. Yes. That is, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so that the trailing edge portion 12 of each blade 10 approaches the rotation shaft 3 over the entire region from the inner peripheral portion 14 to the outer peripheral portion 13. . In other words, the trailing edge 12 of each blade 10 has the positive pressure surface 15 facing inward over the entire area from the inner periphery 14 to the outer periphery 13. With this configuration, the work amount of the impeller 1 can be increased. Specifically, in each of the blades 10, the positive pressure surface 15 faces inward over the entire region from the inner peripheral portion 14 to the outer peripheral portion 13 in the range shown in FIG.

  FIG. 18 is a diagram showing a relationship between the angle φ and the radius R in the blade according to the second embodiment of the present invention. In FIG. 18, the radius R is represented by a dimensionless number called a radius ratio. Specifically, in FIG. 18, the radius R of the position of the inner peripheral portion 14 is “0.0”. Further, in FIG. 18, the radius R of the position of the outer peripheral portion 13 is “1.0”. Further, curves C, D, and E shown in FIG. 18 indicate different positions of the blade 10 in the chord line direction. Specifically, each position of the wing 10 in the chord line direction is represented by a dimensionless number. The position of the rear edge portion 12 is 0.0, and the position of the front edge portion 11 is 1.0. When defined in this way, the curve C indicates a position where the position in the chord line direction is 0.7. A curve D indicates a position where the position in the chord line direction is 0.6. A curve E indicates a position where the position in the chord line direction is 0.5.

  As can be seen from FIG. 18, as the curve C, the curve D, and the curve E are viewed, the value of the angle φ decreases. That is, as the position value in the chord line direction becomes smaller, the angle φ becomes smaller than 90 degrees. The curve E indicating the position where the position in the chord line direction is 0.5 has an angle φ smaller than 90 degrees in the entire region from the inner peripheral portion 14 to the outer peripheral portion 13. That is, in the range where the position in the chord line direction is 0.5 or less, the angle φ is smaller than 90 degrees. In other words, in the range where the position in the chord line direction is 0.5 or less, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to approach the rotation shaft 3. That is, in the range where the position in the chord line direction is 0.5 or less, the normal line of the pressure surface 15 extends from the pressure surface 15 in the rotation direction so as to approach the rotation shaft 3. In other words, the pressure surface 15 faces inward in a range where the position in the chord line direction is 0.5 or less. That is, the pressure surface 15 of each blade 10 is directed inward over the entire region from the inner peripheral portion 14 to the outer peripheral portion 13 on the trailing edge 12 side from the center position in the chord line direction.

  Next, the reason why the impeller 1 according to the second embodiment can suppress the generation of the blade tip vortex 57 in the vicinity of the outer peripheral portion 13 of the blade 10 will be described. Hereinafter, first, the blade tip vortex 57 generated in the impeller of the conventional axial fan will be described. Then, the blade tip vortex 57 generated in the impeller 1 will be described.

  FIG. 19 is a perspective view showing an impeller of a conventional axial fan. In addition, the white arrow shown in FIG. 19 has shown the flow direction of the whole air when the conventional impeller 101 rotates. Moreover, the thick line arrow shown in FIG. 19 has shown the rotation direction of the conventional impeller 101. FIG. Moreover, in FIG. 19, illustration of some wing | blades 110 is abbreviate | omitted among the several wing | blade 110 which the conventional impeller 101 has.

  As described above, when the pressure surface of the blade faces inward, the static pressure tends to increase as compared with the case where the pressure surface of the blade faces the outer peripheral side. That is, when the pressure surface of the blade faces inward, the pressure difference between the pressure surface and the suction surface becomes larger than when the pressure surface of the blade faces the outer peripheral side. When the pressure difference between the pressure surface and the suction surface increases at the outer periphery of the blade, air tends to flow from the pressure surface side to the suction surface side, and blade tip vortices are generated.

  Here, in the conventional impeller 101, the outer peripheral portion 113 of the pressure surface of each blade 110 faces inward in the entire region from the front edge portion 111 to the rear edge portion 112. That is, in the conventional impeller 101, the pressure difference between the pressure surface and the suction surface is large in the outer peripheral portion 113 of the pressure surface of each blade 110 from the front edge portion 111 to the rear edge portion 112. . For this reason, the blade tip vortex 57 is generated from the front edge portion 111 at the outer peripheral portion 113 of each blade 110 of the conventional impeller 101. The blade tip vortex 57 grows and grows toward the trailing edge 112. For this reason, in the conventional impeller 101, the flow path between the blades 110 is blocked by the greatly grown blade tip vortex 57, and the efficiency is lowered.

  On the other hand, in the outer peripheral portion 13 of the pressure surface 15 in each blade 10 of the impeller 1 according to the second embodiment, the pressure surface 15 faces the outer peripheral side at the front edge portion 11. For this reason, as shown in FIG. 14, in the outer peripheral portion 13 of each blade 10 of the impeller 1 according to the second embodiment, the blade tip vortex 57 does not occur in the region where the positive pressure surface 15 faces the outer peripheral side. When the pressure surface 15 is directed to the inner side in the outer peripheral portion 13, the blade tip vortex 57 starts to be generated. For this reason, the impeller 1 according to the second embodiment can delay the generation of the blade tip vortex 57 and can suppress the growth of the blade tip vortex 57. Therefore, in the impeller 1 according to the second embodiment, the area of the flow path between the blades 10 that is blocked by the blade tip vortex 57 is reduced. For this reason, in the impeller 1 according to the second embodiment, more air can flow between the blades 10 than the conventional impeller 101, and the efficiency is improved.

  Moreover, the following effect can also be acquired by setting it as the structure where the positive pressure surface 15 faces the outer peripheral side in the outer peripheral part 13. FIG.

  FIG. 20 is a diagram showing a wind speed distribution on the outlet side of the axial blower according to the second embodiment of the present invention. Specifically, the vertical axis in FIG. 20 indicates the wind speed on the outlet side of the axial flow fan 100. Further, the horizontal axis of FIG. 20 indicates the distance from the rotating shaft 3 of the impeller 1. In the horizontal axis of FIG. 20, the distance from the rotating shaft 3 of the impeller 1 is represented by a dimensionless number called a distance ratio. Specifically, in FIG. 20, the distance from the rotary shaft 3 to the inner peripheral portion 14 of the blade 10 is “0.3”. In FIG. 20, the distance from the rotating shaft 3 to the inner peripheral wall of the bell mouth 21 of the casing 20 is “1.0”.

  In a conventional axial fan, air tends to flow backward between the outer peripheral portion of the blade and the inner peripheral wall of the bell mouth, and a leakage vortex is generated. For this reason, in the conventional axial-flow fan, the wind speed on the blowing side is reduced between the outer peripheral portion of the blade and the inner peripheral wall of the bell mouth. On the other hand, in the axial blower 100 according to the second embodiment, each blade 10 of the impeller 1 has the positive pressure surface 15 facing the outer peripheral side in the outer peripheral portion 13. For this reason, the airflow blown out from the outer peripheral portion 13 of the blade 10 is directed to the outer peripheral side as compared with the conventional case, and collides with the inner peripheral wall of the bell mouth 21. As a result, the axial blower 100 according to the second embodiment can prevent a leakage vortex from occurring between the outer peripheral portion 13 of the blade 10 and the inner peripheral wall of the bell mouth 21. For this reason, as shown in FIG. 20, the axial-flow fan 100 which concerns on this Embodiment 2 can make the wind speed distribution by the side of blowing more uniform than before.

  Each of the blades 10 of the impeller 1 shown in the first embodiment and the second embodiment rotates the blade 10 from the outer peripheral wall of the boss portion 2 more than the radial direction of the virtual circle centering on the rotation axis. It protrudes in the direction side. However, in the impeller of the conventional axial flow fan, each of the blades protrudes from the outer peripheral wall of the boss portion so as to be inclined to the opposite side to the rotation direction of the blade from the radial direction of the virtual circle centering on the rotation shaft. Some have been proposed. Even if each of the blades 10 of the impeller 1 shown in the first embodiment and the present embodiment has such a configuration, the above-described effects can be obtained.

  Moreover, the impeller 1 shown in Embodiment 1 and Embodiment 2 was an impeller for an axial blower. Not only this but the structure of the blade | wing 10 of the impeller 1 may be employ | adopted as the blade | wing of the impeller for mixed flow fans. Even if the configuration of the blade 10 is adopted as a blade of an impeller for a mixed flow fan, the above-described effect can be obtained. For example, by making the boss part 2 into a truncated cone shape and providing each blade 10 on the outer peripheral wall of the boss part 2, an impeller for an axial blower can be obtained.

Embodiment 3 FIG.
In the third embodiment, an example of an air conditioner on which the axial-flow fan 100 shown in the first or second embodiment is mounted will be described. In other words, this Embodiment 3 demonstrates an example of the air conditioning apparatus with which the impeller 1 shown in Embodiment 1 or Embodiment 2 was mounted. Specifically, an example in which the axial blower 100 is mounted on the indoor unit 200 of the air conditioner will be described below. Note that in Embodiment 3, items that are not particularly described are the same as those in Embodiment 1 or Embodiment 2, and the same functions and configurations are described using the same reference numerals.

FIG. 21 is a longitudinal sectional view showing an example of an air-conditioning apparatus according to Embodiment 3 of the present invention. In FIG. 21, the left side of the figure is shown as the front side of the indoor unit 200.
The indoor unit 200 includes a housing 203. A suction port 201 for sucking indoor air into the housing 203 is formed in the upper portion of the housing 203. Further, an air outlet 202 for supplying conditioned air to the air-conditioning target area is formed at the bottom of the housing 203, more specifically, below the front surface of the housing 203. The air outlet 202 is provided with a mechanism for controlling the direction of air flow, such as a vane 202a.

  An axial blower 100 and a heat exchanger 204 are provided inside the housing 203 in an air path extending from the suction port 201 to the blowout port 202. The axial blower 100 is disposed on the downstream side of the suction port 201 and on the upstream side of the heat exchanger 204. A plurality of axial flow fans 100 are arranged in parallel in the longitudinal direction of the housing 203 (in the direction orthogonal to the paper surface) according to the air volume required for the indoor unit 200. The heat exchanger 204 exchanges heat between the indoor air and the refrigerant flowing inside the heat exchanger 204 to create conditioned air.

  When the impeller 1 of the axial blower 100 rotates, room air is taken into the housing 203 from the suction port 201. The indoor air exchanges heat with the refrigerant when passing through the heat exchanger 204 and is heated or cooled to become conditioned air. This conditioned air is blown out from the air outlet 202 at the bottom of the housing 203 to the air-conditioning target area.

  As described above, the impeller 1 shown in the first embodiment and the second embodiment has lower noise than the conventional one. That is, the axial blower 100 shown in the first embodiment and the second embodiment has lower noise than the conventional one. Therefore, the indoor unit 200 including the axial-flow fan 100 shown in the first embodiment or the second embodiment can suppress noise more than in the related art.

  Moreover, as mentioned above, the impeller 1 shown in Embodiment 1 and Embodiment 2 has higher efficiency than the conventional one. That is, the axial blower 100 shown in the first embodiment and the second embodiment has higher efficiency than before. Therefore, the indoor unit 200 including the axial-flow fan 100 shown in the first embodiment or the second embodiment can improve the power efficiency as compared with the related art.

  Moreover, the axial-flow fan 100 shown in Embodiment 2 can make the wind speed distribution on the blowout side more uniform than the conventional one. For this reason, the axial-flow fan 100 shown in the second embodiment has a reduction in blowing performance due to variations in wind speed distribution even when air is flowed into the housing 203 where the pressure loss is increased by the heat exchanger 204 or the like. Can be suppressed. Therefore, the indoor unit 200 including the axial blower 100 illustrated in the second embodiment can further improve the power efficiency as compared to the indoor unit 200 including the axial blower 100 illustrated in the first embodiment.

  DESCRIPTION OF SYMBOLS 1 Impeller, 2 Boss part, 3 Rotating shaft, 10 Wings, 11 Front edge part, 12 Rear edge part, 13 Outer peripheral part, 13a Front end part, 13b Rear end part, 14 Inner peripheral part, 14a Front end part, 14b Rear end Part 15 positive pressure surface 16 negative pressure surface 20 casing 21 bell mouth 30 virtual circle 31 first intersection point 32 second intersection point 41 first virtual straight line 42 second virtual straight line 50 air current 51 vortex 52 High speed flow, 53 vortex, 54 attachment point, 55 air current, 56 air current, 57 tip vortex, 58 air current, 59 air current, 60 air current, 100 axial fan, 101 impeller (conventional), 102 boss (conventional), 103 Rotating shaft (conventional), 110 blades (conventional), 111 leading edge (conventional), 111a tangential direction (conventional), 112 trailing edge (conventional), 113 outer periphery (conventional), 115 pressure surface (conventional), 200 Indoor units, 201 inlet, 202 outlet, 202a vane, 203 housing, 204 heat exchanger.

Claims (11)

A boss that rotates about a rotation axis;
A plurality of wings provided on an outer peripheral wall of the boss portion and rotating around the rotation axis together with the boss portion;
With
Each of the wings is
A front edge that is a front edge in the rotation direction of the blade, a rear edge that is a rear edge in the rotation direction, an outer periphery that is an outer edge, and an inner edge An inner periphery that is a part,
Have
A circle having a radius R centered on the rotation axis is defined as a virtual circle,
In the shape of projecting the boss part and the wing on a plane perpendicular to the rotation axis,
The intersection of the leading edge and the virtual circle is a first intersection,
The intersection of the trailing edge and the virtual circle is a second intersection,
The length of the arc of the virtual circle from the first intersection point to the second intersection point in the same wing is defined as a first wing length L1,
The length of the arc of the imaginary circle from the first intersection of any of the wings to the first intersection of the wings adjacent to the wing is expressed as the inter-blade distance t,
The projection distance ratio σ is σ = L1 / t,
Defined as
The projection distance ratio σ is
From the inner periphery to a position where the radius R becomes the radius RA,
A first minimum value at a position where the radius R is the radius RA;
From the position where the radius R becomes the radius RA to the position where the radius R becomes a radius RM larger than the radius RA,
The radius R has a local maximum at the position where the radius RM becomes the radius RM;
From a position where the radius R becomes the radius RM to a position where the radius R becomes a radius RB larger than the radius RM;
A second minimum value at a position where the radius R becomes the radius RB;
The radius R is configured to increase from the position where the radius RB is reached to the outer periphery,
The radius R, which is an intermediate position between the inner peripheral portion and the radius RA, is the radius RC,
The radius R, which is an intermediate position between the radius RA and the radius RM, is the radius RD,
The radius R, which is an intermediate position between the radius RM and the radius RB, is changed to a radius RE,
The radius R, which is an intermediate position between the radius RB and the outer peripheral portion, is defined as a radius RF,
The radius R, which is not less than the radius RC and not more than the radius RD, is defined as a radius RG,
The radius R, which is greater than the radius RE and less than or equal to the radius RF, is defined as a radius RH,
In the meridional shape of the wing, a distance in a direction parallel to the rotation axis from the front edge portion to the rear edge portion at the position of the radius R is a second wing length L2,
Defined as
L2 / R, which is the ratio of the second blade length L2 to the radius R, is
From the inner periphery to the position where the radius R becomes the radius RG,
The radius R has a maximum value at a position where the radius RG becomes the radius RG;
From a position where the radius R becomes the radius RG to a position where the radius R becomes the radius RH;
A minimum value at a position where the radius R becomes the radius RH;
An impeller having a configuration in which the radius R increases from the position where the radius R becomes the radius RH to the outer peripheral portion. When the radius R is represented by a dimensionless number, the position of the inner periphery is 0.0, and the position of the outer periphery is 1.0,
The radius RA is in the range of 0.2 to 0.3,
The radius RM is within a range of 0.45 or more and 0.55 or less,
The impeller according to claim 1, wherein the radius RB is in a range of 0.7 to 0.8. When the radius R is represented by a dimensionless number, the position of the inner periphery is 0.0, and the position of the outer periphery is 1.0,
The radius RG is within a range of 0.15 or more and 0.25 or less,
The impeller according to claim 1 or 2, wherein the radius RH is within a range of 0.7 to 0.8. In the shape of projecting the boss part and the wing on a plane perpendicular to the rotation axis,
Each of the wings is
It protrudes from the outer peripheral wall of the boss portion to the rotational direction side with respect to the radial direction of the virtual circle, or inclined from the outer peripheral wall of the boss portion to the opposite side of the rotational direction from the radial direction. The impeller as described in any one of Claims 1-3 which protrudes. The projection distance ratio σ at the position of the radius RM is 0.9 or more and less than 1.0,
The impeller according to any one of claims 1 to 4, wherein the projection distance ratio σ at the position of the radius RB is 0.6 or more. Each of the wings is
Has a positive pressure surface,
In the front edge,
Of the range in which the radius R is equal to the radius RA from the inner peripheral portion, in at least a part of the range including the inner peripheral portion, the normal line of the pressure surface is the pressure surface so as to be away from the rotating shaft. Extending in the rotational direction from
In the position where the radius R is the RM, the normal line of the pressure surface extends from the pressure surface in the rotation direction so as to approach the rotation axis,
Of the range from the position where the radius R becomes the radius RB to the outer peripheral portion, in at least a part of the range including the outer peripheral portion, the normal line of the pressure surface is the positive line so as to be away from the rotating shaft. Extending from the pressure surface in the direction of rotation,
In the trailing edge,
The impeller according to any one of claims 1 to 5, wherein a normal line of the pressure surface extends in the rotation direction from the pressure surface so as to approach the rotation axis. Representing each position in the chord line direction of the wing by a dimensionless number, the position of the trailing edge is 0.0, and the position of the leading edge is 1.0,
Each of the blades has a normal to the pressure surface extending from the pressure surface in the rotational direction so as to approach the rotation axis in a range where the position in the chord line direction is 0.5 or less. The impeller according to claim 6. When the radius R is represented by a dimensionless number, the position of the inner periphery is 0.0, and the position of the outer periphery is 1.0,
At the leading edge of each of the wings,
In a range where the radius R is 0.0 or more and 0.15 or less, a normal line of the pressure surface extends from the pressure surface in the rotation direction so as to be away from the rotation axis,
The normal line of the pressure surface extends from the pressure surface in the rotation direction so as to be away from the rotation axis in a range where the radius R is 0.75 or more and 1.0 or less. The impeller described in 1. The impeller according to any one of claims 6 to 8,
A casing in which a bell mouth is formed and the impeller is arranged on the inner peripheral side of the bell mouth;
Blower equipped with. The impeller according to any one of claims 1 to 8,
A heat exchanger for exchanging heat between the air supplied by the rotation of the impeller and the refrigerant flowing inside,
Air conditioner with A blower according to claim 9;
A heat exchanger for exchanging heat between the air supplied by the rotation of the impeller of the blower and the refrigerant flowing inside;
Air conditioner with

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