Impeller, blower, and air conditioner

Abstract

An impeller is provided wherein, when it is assumed that a plurality of imaginary cylinders are centered on the rotation axis and when an imaginary cross section of each of a plurality of blades at each of the cylinder portions is defined as a chord direction cross section, a straight line connecting the leading edge portion and the trailing edge portion in the chord direction cross-section is defined as a chord, the center line of the blade cross section is defined as a camber line, the distance between the camber line and the chord line is defined as a camber, the position on the camber line at which distance from the leading edge portion and from the trailing edge portion are equal is defined as a camber midpoint, and the point of the maximum camber is defined as a maximum value point, then, in the chord direction cross section located close to the inner peripheral edge portion of the blade, the maximum value point is present closer to the trailing edge portion side than the camber midpoint and closer to the air intake side than the chord line, and the camber line has at least one inflection point between the leading edge portion and the maximum value point and, in a chord direction cross section located close to the outer peripheral edge portion of the blade, the maximum value point is present closer to the leading edge portion side than the camber midpoint and closer to the air intake side than the chord line.

Description

Impellers, blowers and air conditioners

[0001] The present disclosure relates to an impeller, a blower, and an air conditioner.

[0002] Conventionally, there are impellers having multiple blades arranged radially (see, for example, Patent Document 1). In the impeller of Patent Document 1, the circumferential center of the root of the blade is designated R1, the circumferential center of the outer periphery of the blade is designated R2, and the rotation center of the blade is designated O. In the impeller of Patent Document 1, the angle between the line connecting O and R1 and the line connecting O and R2 is 18 to 22 degrees, and the line P connecting R1 and R2 is inclined at an angle of 22 to 27 degrees toward the suction side with respect to a plane perpendicular to the rotation axis passing through R1. The impeller of Patent Document 1 has an inflection point within the blade cross section in the circumferential direction. In the impeller of Patent Document 1, the discharge side from the leading edge to the inflection point in the rotation direction of the blade is convex, and the discharge side from the inflection point to the trailing edge in the rotation direction of the blade is concave. The impeller of Patent Document 1 has these convex and concave shapes formed over the entire length of the blades from the base to the outer periphery.

[0003] Japanese Patent Application Publication No. 09-068200

[0004] The efficiency of an impeller is improved by suppressing separation that occurs on the blade surface. The impeller of Patent Document 1 has blades formed with the above-mentioned configuration, and is therefore said to be able to reduce noise caused by the rotation of the blades during rotation of the impeller. However, the impeller of Patent Document 1 has a convex shape on the leading edge side and a concave shape on the trailing edge side along the entire length of the blade from the base to the outer periphery, so the convex shape on the outer periphery side, where the airflow is faster than on the inner periphery side of the impeller, may cause airflow separation and deteriorate air blowing performance.

[0005] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an impeller, a blower, and an air conditioner that suppress airflow separation and improve blowing performance.

[0006] The impeller according to the present disclosure includes a boss portion provided on a rotation shaft and a plurality of blades provided on the outer periphery of the boss portion, and each of the plurality of blades has a leading edge portion which is the edge on the front side in the rotation direction, a trailing edge portion which is the edge on the rear side in the rotation direction, an outer peripheral end portion which is the edge on the outer periphery, and an inner peripheral edge portion which is the edge on the inner periphery, and when a plurality of imaginary cylinders are imagined as being centered on the rotation shaft, each imaginary cross section of the plurality of blades corresponding to the cylindrical portion is defined as a chord direction cross section, a straight line connecting the leading edge portion and the trailing edge portion in the chord direction cross section is defined as a chord, and a center line of the blade cross section is defined as a camber line, and the camber line and the chord in a direction perpendicular to the chord in the chord direction cross section are defined as a camber line. is defined as the distance between the leading edge and the trailing edge as the camber height, the position on the camber line where the distance from the leading edge is equal to the distance from the trailing edge is defined as the camber midpoint, and the point on the camber line where the camber height is greatest is defined as the maximum extreme point. In this case, in a cross section in the chord direction that is closer to the inner peripheral edge than the outer peripheral edge of the blade, the maximum extreme point is located closer to the trailing edge than the camber midpoint and on the air intake side than the chord, and the camber line has at least one inflection point between the leading edge and the maximum extreme point, and in a cross section in the chord direction that is closer to the outer peripheral edge than the inner peripheral edge of the blade, the maximum extreme point is located closer to the leading edge than the camber midpoint and on the air intake side than the chord.

[0007] The blower according to the present disclosure includes a casing having a bell mouth and an impeller of the above configuration housed inside the casing, and the length of the casing in the axial direction of the rotation shaft is defined as a length H ｂ When the coefficient ε is defined as 0<ε≦0.5, the impeller has a length εH on the air intake side and the air outlet side in the axial direction of the rotation shaft. ｂ The sensor is disposed in a region inside a virtual plane located at a distance of 100 mm from the casing.

[0008] An air conditioner according to the present disclosure includes an impeller having the above-described configuration, and a heat exchanger that exchanges heat between air supplied by the impeller and a refrigerant circulating inside the heat exchanger.

[0009] According to the present disclosure, the impeller, and the impeller of a blower and an air conditioner are configured as follows. In a cross section in the chord direction at a position closer to the inner circumferential edge of the blade than the outer circumferential edge, the maximum extreme point is located closer to the trailing edge than the camber midpoint and closer to the air suction side than the chord. The camber line has at least one inflection point between the leading edge and the maximum extreme point. In a cross section in the chord direction at a position closer to the outer circumferential edge of the blade than the inner circumferential edge, the maximum extreme point is located closer to the leading edge than the camber midpoint and closer to the air suction side than the chord. By having this configuration, the impeller can direct the airflow along the blade, thereby suppressing airflow separation on the leading edge side of the outer circumferential side of the blade and improving blowing performance.

[0010] 1 is a perspective view showing the configuration of an impeller according to a first embodiment and a blower including the same.

[0023] FIG. 2 is a conceptual diagram for explaining the basic configuration of the impeller according to the first embodiment, showing the impeller projected onto a plane perpendicular to the rotation axis.

[0024] FIG. 3 is a conceptual diagram of a cross section taken along line III-III in FIG. 2, viewed in the direction of the arrows.

[0025] FIG. 4 is a conceptual diagram showing an example of a chord direction cross section of a blade of the impeller according to the first embodiment.

[0026] FIG. 5 is a conceptual diagram showing the chord and camber lines in the chord direction cross section taken along line IV-IV in FIG. 2.

[0027] FIG. 6 is a conceptual diagram showing the chord and camber lines in the chord direction cross section taken along line V-V in FIG. 2, for explaining the operation and airflow of the impeller according to the first embodiment.

[0028] FIG. 7 is a conceptual diagram showing the chord and camber lines in the chord direction cross section taken along line V-V in FIG. 2, for explaining the operation and airflow of the impeller according to the first embodiment.

[0029] 2 is a conceptual diagram showing the chord and camber lines of an impeller according to a second embodiment, in a cross section in the chord direction taken along line V-V in FIG. 2. FIG. 3 is a graph showing the relationship between the flow coefficient and the fan efficiency of the impeller according to the second embodiment and an impeller of the prior art. FIG. 4 is a graph showing the relationship between the flow coefficient and the pressure coefficient of the impeller according to the second embodiment and an impeller of the prior art. FIG. 5 is a conceptual diagram showing the chord and camber lines of an impeller according to a third embodiment, in a cross section in the chord direction taken along line IV-IV in FIG. 2. FIG. 6 is a conceptual diagram showing the chord and camber lines of an impeller according to the third embodiment, in a cross section in the chord direction taken along line V-V in FIG. 2. FIG. 7 is a conceptual diagram showing the cross section of a blower according to a fourth embodiment, in an arbitrary plane parallel to and passing through the rotation axis of the blower shown in FIG. 1. FIG. 8 is a perspective view showing the configuration of an air conditioner according to a fifth embodiment.

[0011] An impeller, a blower, and an air conditioner according to embodiments will be described below with reference to the drawings. Note that in the following drawings, including FIG. 1 , the relative dimensional relationships and shapes of the components may differ from those in actuality. Furthermore, in the following drawings, identical reference numerals denote identical or equivalent components, and this applies throughout the specification. To facilitate understanding, directional terms (e.g., "up," "down," "right," "left," "front," and "rear") are used as appropriate. However, these terms are used for convenience of explanation only and do not limit the arrangement or orientation of the device or components. Furthermore, although the following drawings do not show chamfered edges, similar effects can be achieved even if chamfered edges are used. For example, the impeller, blower, and air conditioner can achieve similar effects whether C-chamfered or R-chamfered edges are used.

[0012] Embodiment 1. [Blower 100] Figure 1 is a perspective view showing the configuration of an impeller 10 and a blower 100 including the same according to Embodiment 1. Figure 1 shows a portion of the configuration of the blower 100 as viewed from the suction side, i.e., the suction surface 26 side of the blades 20. In Figure 1 and the figures described below, a thick black arrow R indicates the rotation direction of the impeller 10, i.e., the rotation direction of the boss portion 12 and the blades 20, which are part of the impeller 10. Furthermore, a double-headed arrow CD in the figure indicates the circumferential direction of the impeller 10.

[0013] 1 and the drawings described below, the outlined thick arrow F indicates the overall direction of air flow when the impeller 10 rotates. In the air flow direction indicated by the outlined thick arrow F, the Y1 side of the impeller 10 is the upstream side of the airflow relative to the impeller 10, and the Y2 side of the impeller 10 is the downstream side of the airflow relative to the impeller 10. In other words, the Y1 side is the air intake side of the impeller 10, and the Y2 side is the air blowout side of the impeller 10.

[0014] 1 is a direction perpendicular to the rotation shaft 11 of the impeller 10 and represents the radial direction of the impeller 10. In the radial direction, the X2 side portion is located on the outer periphery side of the X1 side portion, and the X1 side portion is located on the inner periphery side of the X2 side portion. In other words, the X1 side of the impeller 10 is the inner periphery side of the impeller 10, and the X2 side of the impeller 10 is the outer periphery side of the impeller 10. The rotation shaft 11 is a virtual rotation axis when the impeller 10 rotates.

[0015] An impeller 10 and a blower 100 including the same according to a first embodiment will be described using Figure 1. The blower 100 according to the first embodiment is a device that forms an air flow and is used to blow air. The blower 100 according to the first embodiment is an axial flow blower that blows air in a direction along a rotating shaft 11. The blower 100 is used, as an example, in an air conditioner 200 (see Figure 16) described below.

[0016] As shown in Fig. 1, the blower 100 has a casing 80 and an impeller 10. The casing 80 forms the outer shell of the blower 100. The casing 80 is formed, for example, in a box shape (not shown). The casing 80 has a substantially cylindrical bell mouth 81. The impeller 10 is disposed on the inner periphery of the bell mouth 81. The impeller 10 is provided so as to be rotatable about a rotation shaft 11. The blower 100 also has a drive unit (not shown), such as a motor, that rotates the impeller 10.

[0017] [Impeller 10] Figure 2 is a conceptual diagram for explaining the basic configuration of the impeller 10 according to the first embodiment, and is a diagram of the impeller 10 projected onto a plane perpendicular to the rotation shaft 11. Note that the impeller 10 shown in Figure 2 is a conceptual diagram used to explain the basic configuration, and the relative dimensional relationships and shapes of the respective components may differ from the actual ones. Figure 2 shows the configuration of the impeller 10 as seen from the suction surface 26 side of the blade 20. The impeller 10 according to the first embodiment will be described using Figures 1 and 2.

[0018] The impeller 10 is an axial flow impeller, and is a device for forming a flow of a fluid such as air. The impeller 10 forms a flow of air by rotating around a rotary shaft 11 in the direction of rotation indicated by the thick black arrow R. As shown in Figure 2, the impeller 10 includes a boss portion 12 provided on the rotary shaft 11 and a plurality of blades 20 provided on the outer periphery of the boss portion 12.

[0019] (Boss portion 12) The boss portion 12 has a substantially cylindrical shape. A drive shaft (not shown) provided in the drive unit is connected to the center of the boss portion 12. The boss portion 12 rotates around the rotation axis 11 as a rotational driving force is transmitted from the drive unit via the drive shaft. The boss portion 12 is rotationally driven by the drive unit to form the rotation axis 11.

[0020] (Multiple Blades 20) The multiple blades 20 transport air by pushing the air present between the blades 20 as the impeller 10 rotates. The multiple blades 20 are arranged at approximately equal angular intervals on the outer circumferential side of the boss portion 12. Each of the multiple blades 20 protrudes approximately radially from the outer circumferential wall of the boss portion 12. Each of the multiple blades 20 is formed around the boss portion 12 and extends radially outward from the boss portion 12.

[0021] More specifically, each of the plurality of blades 20 protrudes radially outward from the outer peripheral wall of the boss portion 12, inclined forward in the direction of rotation of the impeller 10, with respect to the radial direction centered on the rotation shaft 11. While Fig. 2 illustrates an impeller 10 having four blades 20, the number of blades 20 that the impeller 10 has is not limited to four, and may be less than four or more than four.

[0022] Each of the multiple blades 20 has a leading edge 21, a trailing edge 22, an outer peripheral end 23, and an inner peripheral edge 24. The leading edge 21 is the edge of the periphery of the blade 20 that is forward in the direction of rotation. The trailing edge 22 is the edge of the periphery of the blade 20 that is rearward in the direction of rotation. The outer peripheral end 23 is the edge of the periphery of the blade 20 on the outer side. The outer peripheral end 23 forms the outer edge between the leading edge 21 and the trailing edge 22. The inner peripheral edge 24 is the edge of the periphery of the blade 20 on the inner side. The inner peripheral edge 24 has a shape that follows the outer peripheral wall of the boss portion 12 and is connected to the outer peripheral wall.

[0023] The outer peripheral end 23 and the leading edge 21 are adjacent to each other via an outer peripheral front end 23a. The outer peripheral front end 23a is the front end of the outer peripheral end 23 in the rotational direction and is the outer peripheral end of the leading edge 21 in the radial direction of the rotating shaft 11. The outer peripheral end 23 and the trailing edge 22 are adjacent to each other via an outer peripheral rear end 23b. The outer peripheral rear end 23b is the rear end of the outer peripheral end 23 in the rotational direction and is the outer peripheral end of the trailing edge 22 in the radial direction of the rotating shaft 11.

[0024] The inner circumferential edge 24 and the leading edge 21 are adjacent to each other via an inner circumferential front end portion 24a. The inner circumferential front end portion 24a is the front end portion of the inner circumferential edge 24 in the rotational direction and is the inner circumferential end portion of the leading edge 21 in the radial direction of the rotating shaft 11. The inner circumferential edge 24 and the trailing edge 22 are adjacent to each other via an inner circumferential rear end portion 24b. The inner circumferential rear end portion 24b is the rear end portion of the inner circumferential edge 24 in the rotational direction and is the inner end portion of the trailing edge 22 in the radial direction of the rotating shaft 11.

[0025] Each of the multiple blades 20 has a pressure surface 25 and a suction surface 26 as blade surfaces 35. The pressure surface 25 is the surface on the front side in the direction of rotation of the two blade surfaces 35 that the blade 20 has. When the blade 20 rotates, the air is pushed by the pressure surface 25. The suction surface 26 is the surface on the rear side in the direction of rotation of the two blade surfaces 35 that the blade 20 has, and is the surface behind the pressure surface 25. Because Figures 1 and 2 show the configurations of the blower 100 and the impeller 10, respectively, as viewed from the suction surface 26 side, the pressure surface 25 is indicated by a dashed leading line.

[0026] In the direction of air flow indicated by the thick white arrow F, the surface of the blade surface 35 facing the upstream side (Y1 side) of the blade 20 is the suction surface 26, and the surface facing the downstream side (Y2 side) is the pressure surface 25. The pressure surface 25 is the surface facing the rotation direction of the blade 20, and the suction surface 26 is the surface facing the opposite side to the rotation direction of the blade 20.

[0027] The plurality of blades 20 rotate together with the boss portion 12 around the rotation shaft 11. When the plurality of blades 20 rotate, as shown by the thick white arrow F in Fig. 1, air flows from the front side of the page along the rotation shaft 11 and is sucked into the fan 100. In Fig. 2, the air sucked into the fan 100 flows along the rotation shaft 11 and is blown out from the fan 100 toward the back side of the page.

[0028] Fig. 3 is a conceptual diagram of a cross section taken along line III-III in Fig. 2, viewed in the direction of the arrows. Fig. 4 is a conceptual diagram showing an example of a chord direction cross section CS of the blade 20 of the impeller 10 according to the first embodiment. Fig. 5 is a conceptual diagram showing the chord 30 and the camber line 31 in the chord direction cross section CS1 taken along line IV-IV in Fig. 2. Fig. 6 is a conceptual diagram showing the chord 30 and the camber line 31 in the chord direction cross section CS2 taken along line V-V in Fig. 2. In each of Figs. 3, 5, and 6, the up-down direction represents the direction along the rotation shaft 11, with the upper side representing the suction side and the lower side representing the blowing side.

[0029] 2, when multiple imaginary cylinders CL are assumed to be centered on the rotation axis 11, each imaginary cross section of the multiple blades 20 corresponding to the cylindrical portion is defined as a "chord direction cross section CS." In other words, when the blade 20 is cut by the imaginary cylinder CL centered on the rotation axis 11, the cross section of the imaginary blade 20 is defined as a "chord direction cross section CS."

[0030] The blade 20 has a plurality of chord direction cross sections CS in the radial direction centered on the rotation shaft 11. The chord direction cross sections CS shown in Fig. 4 are an example. The blade surfaces 35, such as the pressure surface 25 and the suction surface 26, shown in Fig. 4 are an example, and the blade surfaces 35 are not limited to the illustrated form. Here, as an example, among the plurality of chord direction cross sections CS, the cross section at the position of line IV-IV in Fig. 2 is referred to as chord direction cross section CS1, and the cross section at the position of line V-V in Fig. 2 is referred to as chord direction cross section CS2.

[0031] 5 and 6, the straight line connecting the leading edge 21 and the trailing edge 22 in the chord direction cross section CS is defined as the "blade chord 30," and the center line of the blade cross section connecting the leading edge 21 and the trailing edge 22 in the chord direction cross section CS is defined as the "camber line 31." The center line of the blade cross section is a line passing through the center between the pressure surface 25 and the suction surface 26 in the chord direction cross section CS. In order to show the relationship between the chord 30 and the camber line 31, blade surfaces 35 such as the pressure surface 25 and the suction surface 26 of the blade 20 are not shown in FIGS. 5 and 6, and only the chord 30 and the camber line 31 are shown.

[0032] Furthermore, in each of the multiple chord direction cross sections CS, a point at which the ratio of the distance from the leading edge 21 to the distance from the trailing edge 22 is a constant value is defined as an "imaginary point P." A line connecting each of the multiple chord direction cross sections CS from the inner circumferential edge 24 to the outer circumferential end 23 is defined as a "span line 27" (see FIG. 2). The ratio of the distance from the leading edge 21 to the distance from the trailing edge 22 is determined based on the required design objective.

[0033] The distances from each of the leading edge 21 and the trailing edge 22 to the imaginary point P are measured, for example, along the camber line of the blade 20 on the cylindrical cross section. That is, the distances from each of the leading edge 21 and the trailing edge 22 to the imaginary point P are measured, for example, along the camber line 31 of the blade 20 on the chord direction cross section CS. Note that the position of point P shown in Figures 5 and 6 is an example and is not limited to the position shown in Figures 5 and 6.

[0034] The direction from the inner peripheral edge 24 toward the outer peripheral end 23 along the span line 27 is defined as the "span direction." Furthermore, a cross section of the blade 20 cut along the span line 27 parallel to the rotation axis 11 is defined as the "span direction cross section SS." The cross section shown in Figure 3 is the span direction cross section SS cut through the blade 20 along one span line 27.

[0035] Span lines 27a, 27b, and 27c shown in Fig. 2 are examples of span lines 27 showing the spanwise cross section SS of the blade 20. Span line 27b shown in Fig. 2 is a span line 27 that passes through an imaginary point P that is the midpoint between the leading edge 21 and the trailing edge 22 in a chordwise cross section CS, which is a cylindrical cross section of the blade 20. That is, in the chordwise cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the span line 27b is equal to the distance between the trailing edge 22 and the span line 27b. That is, in the chordwise cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the imaginary point P is equal to the distance between the trailing edge 22 and the imaginary point P.

[0036] The span line 27a shown in Fig. 2 is one of the span lines 27 located closer to the leading edge 21 than the span line 27b. The span line 27a shown in Fig. 2 is the span line 27 that passes through an imaginary point P that is closer to the leading edge 21 than the midpoint between the leading edge 21 and the trailing edge 22 in the chord cross section CS, which is a cylindrical cross section of the blade 20. That is, in the chord cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the span line 27a is smaller than the distance between the trailing edge 22 and the span line 27a. That is, in the chord cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the imaginary point P is smaller than the distance between the trailing edge 22 and the imaginary point P.

[0037] The span line 27c shown in Fig. 2 is one of the span lines 27 located closer to the trailing edge 22 than the span line 27b. The span line 27c shown in Fig. 2 is the span line 27 that passes through an imaginary point P that is closer to the trailing edge 22 than the midpoint between the leading edge 21 and the trailing edge 22 in the chord cross section CS, which is a cylindrical cross section of the blade 20. That is, in the chord cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the span line 27c is greater than the distance between the trailing edge 22 and the span line 27c. That is, in the chord cross section CS of the blade 20 centered on the rotation axis 11, the distance between the leading edge 21 and the imaginary point P is greater than the distance between the trailing edge 22 and the imaginary point P.

[0038] 3, the spanwise cross section SS of the blade 20 on the trailing edge 22 side is convex on the suction side from the inner peripheral edge 24 to the outer peripheral end 23, for example, over the entire region between the inner peripheral edge 24 and the outer peripheral end 23. That is, the blade 20 on the trailing edge 22 side is curved in the region between the radial intermediate portion 28 and the outer peripheral end 23, so that the suction side is convex and the blowing side is concave from the radial intermediate portion 28 to the outer peripheral end 23.

[0039] The midpoint between the connection portion of the boss 12 with the leading edge 21 and the connection portion of the boss 12 with the trailing edge 22 is defined as the "boss midpoint 12a," and a cross section perpendicular to the axial direction of the rotation shaft 11 that passes through the boss midpoint 12a is defined as the "boss mid-section 40." The distance between the boss mid-section 40 and a spanwise cross section SS on the trailing edge 22 side in the axial direction of the rotation shaft 11 is defined as the "trailing-edge-side blade height Sh." If the extreme value point on the spanwise cross section SS of the blade 20 on the trailing edge 22 side where the "trailing-edge-side blade height Sh" is minimum from the inner peripheral edge 24 to the outer peripheral end 23 is defined as the "trailing-edge-side recess 29," the blade 20 has the "trailing-edge-side recess 29."

[0040] The distance from the rotation axis 11 to any point on the boss mid-section 40 is defined as "distance r." As shown in FIG. 2, the distance from the rotation axis 11 to the inner peripheral edge 24 is defined as distance r1, and the distance from the rotation axis 11 to the outer peripheral end 23 is defined as distance r2. In this case, if v is defined as v = (r - r1) / (r2 - r1), it is desirable that the trailing edge recess 29 be in the range of 0.4 < v < 0.8.

[0041] 5 and 6, the distance from the chord 30 on the camber line 31 is defined as the "camber height H." The camber height H is the distance between the camber line 31 and the chord 30 in a direction perpendicular to the chord 30 in the chord direction cross section CS. The point on the camber line 31 where the camber height H is maximum is defined as the "maximum extreme point 33," and the position on the camber line 31 where the distance from the leading edge 21 and the distance from the trailing edge 22 are equal is defined as the "camber midpoint 34."

[0042] As shown in Figure 5, in a chord direction cross section CS1 located closer to the inner circumferential edge 24 than the outer circumferential end 23 of the blade 20, a maximum extreme value point 33 is located closer to the trailing edge 22 than the camber midpoint 34 and closer to the air suction side than the chord 30. As shown in Figure 5, in a chord direction cross section CS1 located closer to the inner circumferential edge 24 than the outer circumferential end 23 of the blade 20, the camber line 31 has at least one inflection point 32 between the leading edge 21 and the maximum extreme value point 33. The inflection point 32 is a point where the camber line 31 changes from being convex toward the suction side to being convex toward the blowing side, or from being convex toward the blowing side to being convex toward the suction side, as it moves from the leading edge 21 to the trailing edge 22.

[0043] As shown in FIG. 6 , in the chord direction cross section CS2 located closer to the outer peripheral end 23 than the inner peripheral edge 24 of the blade 20, the maximum extreme point 33 is located closer to the leading edge 21 than the camber midpoint 34 and closer to the air intake side than the chord 30.

[0044] [Operation and Effect of Impeller 10] The impeller 10 is configured as follows. In a chord-direction cross section CS1 located closer to the inner circumferential edge 24 of the blade 20 than the outer circumferential edge 23, the maximum extreme value point 33 is located closer to the trailing edge 22 than the camber midpoint 34 and closer to the air suction side than the chord 30. The camber line 31 has at least one inflection point 32 between the leading edge 21 and the maximum extreme value point 33. In a chord-direction cross section CS2 located closer to the outer circumferential edge 23 of the blade 20 than the inner circumferential edge 24, the maximum extreme value point 33 is located closer to the leading edge 21 than the camber midpoint 34 and closer to the air suction side than the chord 30. By having this configuration, the impeller 10 can direct the airflow along the blade 20, thereby suppressing airflow separation on the leading edge 21 side of the outer circumferential side of the blade 20. Therefore, the impeller 10 can improve the air blowing performance and increase the air blowing efficiency, thereby achieving high fan efficiency.

[0045] In a typical axial flow fan, the efficiency of the impeller is improved by suppressing separation on the blade surface. Furthermore, the impeller can achieve a large air volume by increasing the blade area or the rotation speed. However, it is not possible to increase the blade area so that the height of the impeller blades exceeds the design constraint, or to increase the rotation speed so that the impeller rotates beyond the maximum rotation speed determined by the impeller strength and the upper limit of the motor capacity.

[0046] In the impeller of Patent Document 1, the circumferential center of the root of the blade is designated as R1, the circumferential center of the outer periphery of the blade is designated as R2, and the center of rotation of the blade is designated as O. In the impeller of Patent Document 1, the angle formed between the line connecting O and R1 and the line connecting O and R2 is 18 to 22 degrees, and the line P connecting R1 and R2 is inclined at an angle of 22 to 27 degrees toward the suction side with respect to a plane perpendicular to the rotation axis that passes through R1.

[0047] The blades of the impeller described in Patent Document 1 have an inflection point within the cross section of the blade in the circumferential direction. In the impeller of Patent Document 1, the discharge side between the leading edge of the blade in the rotation direction and the inflection point is convex, and the discharge side between the inflection point and the trailing edge of the blade in the rotation direction is concave. In the impeller of Patent Document 1, the blades are formed so that these convex and concave shapes are formed over the entire length from the base of the blade to the outer periphery, which is said to reduce noise caused by the rotation of the blade during impeller rotation without increasing the height of the blade.

[0048] In an impeller, the magnitude of the rotational component of the airflow passing through the leading edge of the blade is proportional to the radius. Therefore, the magnitude of the rotational component of the airflow passing through the leading edge of the blade is smaller at a position closer to the inner peripheral edge than to the outer peripheral edge than to the inner peripheral edge, and is larger at a position closer to the outer peripheral edge than to the inner peripheral edge than to the outer peripheral edge. In other words, the magnitude of the rotational component of the airflow passing through the leading edge of the blade becomes smaller as it approaches the inner peripheral edge in the radial direction, and becomes larger as it approaches the outer peripheral edge.

[0049] The blades of the impeller described in Patent Document 1 have a convex shape on the leading edge side and a concave shape on the trailing edge side along the entire length from the root of the blade to the outer periphery, so the convex shape on the outer periphery side, where the airflow is faster, can cause airflow separation and deteriorate air blowing performance. Therefore, it is necessary for the impeller to suppress airflow separation on the leading edge side of the outer periphery of the blade.

[0050] 7 is a conceptual diagram illustrating the operation of the impeller 10 and the airflow according to the first embodiment, showing the blade chord 30 and the camber line 31 in a chord direction cross section CS1 taken along line IV-IV in FIG. 2. The vertical direction in FIG. 7 represents the direction along the rotation shaft 11, with the upper side representing the air intake side and the lower side representing the air blowing side. In FIG. 7, the dashed arrow FA indicates the airflow around the blade 20.

[0051] As shown in FIG. 7 , in a chord direction cross section CS1 at a position closer to the inner peripheral edge 24 than the outer peripheral end 23 of the blade 20, the maximum extreme point 33 is located closer to the trailing edge 22 than the camber midpoint 34 and closer to the air intake side than the chord 30.

[0052] 7, the airflow is bent so that the radius of curvature is smaller on the trailing edge 22 side of the blade 20, i.e., closer to the trailing edge 22 than to the leading edge 21, thereby increasing the rise in static pressure of the blade 20. Therefore, the impeller 10 can increase the air volume at the same rotation speed of the blade 20 compared to a case without this configuration.

[0053] In addition to the above-described shape, as shown in FIGS. 5 and 7 , in a chord direction cross section CS1 at a position closer to the inner peripheral edge 24 than to the outer peripheral end 23 of the blade 20, the camber line 31 has at least one inflection point 32 between the leading edge 21 and the maximum extreme point 33.

[0054] As a result, compared to a case where the impeller 10 does not have this configuration, it is possible to reduce the radius of curvature on the trailing edge 22 side of the blade 20, while simultaneously suppressing airflow separation on the leading edge 21 side of the blade 20, and to increase the airflow sending efficiency of the blade 20. In other words, the impeller 10 is able to reduce the radius of curvature in the portion of the blade 20 closer to the trailing edge 22 than the leading edge 21, while simultaneously suppressing airflow separation in the portion of the blade 20 closer to the leading edge 21 than the trailing edge 22, and to increase the airflow sending efficiency of the blade 20. Therefore, the impeller 10 can achieve higher fan efficiency than a case where it does not have the above configuration.

[0055] In addition, the positions of the leading edge 21 and the trailing edge 22 of the blades 20 do not change in the impeller 10 compared to when the impeller 10 does not have the above configuration. Therefore, the impeller 10 can obtain the above effects, such as improving the fan efficiency of the impeller 10 and increasing the air volume at the same rotation speed, without changing the size of the impeller 10.

[0056] Figure 8 is a conceptual diagram illustrating the operation of the impeller 10 and the airflow according to the first embodiment, showing the blade chord 30 and the camber line 31 in a chord direction cross section CS2 taken along line V-V in Figure 2. The vertical direction in Figure 8 represents the direction along the rotation shaft 11, with the upper side representing the air intake side and the lower side representing the air blowing side. In Figure 8, dashed arrows FA indicate the airflow around the blades 20.

[0057] As shown in FIG. 8 , in the chord direction cross section CS2 at a position closer to the outer peripheral end 23 than the inner peripheral edge 24 of the blade 20, the maximum extreme point 33 is located closer to the leading edge 21 than the camber midpoint 34 and closer to the air intake side than the chord 30.

[0058] As described above, the magnitude of the rotational component of the airflow passing through the leading edge of the blade is proportional to the radius, so the magnitude of the rotational component of the airflow passing through the leading edge of the blade on the outer peripheral end side is greater than the magnitude of the rotational component of the airflow passing through the leading edge of the blade on the inner peripheral edge side. As a result, in the portion of the impeller 10 closer to the outer peripheral end 23 than to the inner peripheral edge 24 of the blade 20, the airflow that has passed through the leading edge 21 side flows along the blade 20, thereby suppressing airflow separation and improving the air blowing efficiency of the blade 20. Therefore, the impeller 10 can achieve higher fan efficiency than a blade not having the above configuration.

[0059] Furthermore, in the impeller 10, the maximum extreme point 33 is located closer to the leading edge 21 than the camber midpoint 34 and closer to the air suction side than the chord 30, thereby making it possible to reduce the radius of curvature on the leading edge 21 side of the blade 20. In other words, in the impeller 10, the maximum extreme point 33 is located closer to the leading edge 21 than the camber midpoint 34 and closer to the air suction side than the chord 30, thereby making it possible to reduce the radius of curvature in the portion of the blade 20 closer to the leading edge 21 than the trailing edge 22.

[0060] Therefore, compared to an impeller not having the above configuration, the impeller 10 can increase the static pressure increase on the leading edge 21 side of the blade 20, thereby reducing the pressure gradient from the leading edge 21 side to the trailing edge 22 side of the blade 20. As a result, compared to an impeller not having the above configuration, the impeller 10 can increase the air volume at the same rotation speed of the blade 20. Therefore, the impeller 10 can achieve higher fan efficiency compared to an impeller not having the above configuration.

[0061] In addition, the positions of the leading edge 21 and the trailing edge 22 of the blades 20 do not change in the impeller 10 compared to when the impeller 10 does not have the above configuration. Therefore, the impeller 10 can obtain the above effects, such as improving the fan efficiency of the impeller 10 and increasing the air volume at the same rotation speed, without changing the size of the impeller 10.

[0062] Second Embodiment Figure 9 is a conceptual diagram of the impeller 10 according to a second embodiment, showing the chord 30 and camber line 31 at a chord direction cross section CS1 taken along line IV-IV in Figure 2. Figure 10 is a conceptual diagram of the impeller 10 according to the second embodiment, showing the chord 30 and camber line 31 at a chord direction cross section CS2 taken along line V-V in Figure 2. Next, the impeller 10 according to the second embodiment will be described.

[0063] The impeller 10 according to the second embodiment is characterized by a chord direction cross section CS of the blades 20 centered on the rotating shaft 11. The impeller 10 according to the second embodiment is similar to the impeller 10 according to the first embodiment in configuration other than that described below. The features of the impeller 10 according to the second embodiment will be described with reference to Figures 2, 9, and 10 already shown. Components having the same functions and actions as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0064] 2, 9, and 10, the impeller 10 is formed so that the camber line 31 is located closer to the air suction side than the chord 30 over the entire area of ​​the blade 20 in the radial direction of the rotary shaft 11. In other words, the impeller 10 is formed so that the camber line 31 is located closer to the air suction side than the chord 30 at any cross section CS in the chord direction from the inner peripheral edge 24 to the outer peripheral end 23 of the blade 20.

[0065] [Effects of the Impeller 10] The impeller 10 is formed so that the camber line 31 is located closer to the air suction side than the chord 30 over the entire area of ​​the blade 20 in the radial direction of the rotary shaft 11. Because the impeller 10 is formed so that the camber line 31 is located closer to the air suction side than the chord 30 over the entire area of ​​the blade 20, the amount of pressure rise of the impeller 10 can be increased and fan efficiency can be improved compared to impellers that do not have this configuration.

[0066] If the camber line of a portion of the blade is formed so that it is located closer to the air outlet side than the chord, the airflow will be bent significantly in the opposite direction to the direction in which the pressure increase effect is obtained by that portion, and the impeller will not perform the work of the blade. Therefore, if the camber line of a portion of the blade is formed so that it is located closer to the air outlet side than the chord, the amount of pressure increase of the impeller will be small. Alternatively, the airflow will not flow along the blade at that portion of the impeller, causing airflow separation, and the fan efficiency of the impeller will deteriorate. In contrast, the blade 20 of the impeller 10 according to embodiment 2 is formed so that the camber line 31 is located closer to the air intake side than the chord 30 throughout the entire blade 20, so the amount of pressure increase of the impeller 10 can be increased and the fan efficiency can be improved compared to an impeller not having this configuration.

[0067] Fig. 11 is a graph showing the relationship between the flow coefficient and the fan efficiency of the impeller 10 according to the second embodiment and a conventional impeller. In Fig. 11, circles indicate the impeller of the conventional embodiment, and crosses indicate the impeller 10 according to the second embodiment. The conventional impeller is a general impeller that does not have the characteristics of the impeller 10 according to the second embodiment. As shown in Fig. 11, the impeller 10 according to the second embodiment has a higher fan efficiency relative to the flow coefficient in all ranges compared to the conventional impeller, and therefore has improved fan efficiency compared to the conventional impeller.

[0068] Fig. 12 is a graph showing the relationship between the flow coefficient and the pressure coefficient for the impeller 10 according to the second embodiment and a conventional impeller. In Fig. 12, circles indicate the impeller of the conventional embodiment, and crosses indicate the impeller 10 according to the second embodiment. The conventional impeller is a general impeller that does not have the characteristics of the impeller 10 according to the second embodiment. As shown in Fig. 12, the impeller 10 according to the second embodiment has a higher pressure coefficient relative to the flow coefficient in all ranges compared to the conventional impeller, and therefore can increase the air volume at the same rotation speed compared to the conventional impeller.

[0069] Third Embodiment Figure 13 is a conceptual diagram of the impeller 10 according to a third embodiment, showing the chord 30 and camber line 31 in a chord direction cross section CS1 taken along line IV-IV in Figure 2. Figure 14 is a conceptual diagram of the impeller 10 according to the third embodiment, showing the chord 30 and camber line 31 in a chord direction cross section CS2 taken along line V-V in Figure 2. Next, the impeller 10 according to the third embodiment will be described.

[0070] The impeller 10 according to the third embodiment is characterized by a chord direction cross section CS of the blade 20 centered on the rotation shaft 11 in the portions near the inner peripheral edge 24 and the outer peripheral end 23. The impeller 10 according to the third embodiment is similar to the impeller 10 according to the first or second embodiment in configuration other than that described below. The features of the impeller 10 according to the third embodiment will be described with reference to Figures 2, 13, and 14 already shown. Components having the same functions and actions as those in the first or second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0071] As described above, the distance from the chord 30 to the camber line 31 is defined as the "camber height H." The camber height H is the distance between the camber line 31 and the chord 30 in a direction perpendicular to the chord 30 in the chord direction cross section CS.

[0072] Regarding the camber height H, as shown in FIG. 13, in a chord direction cross section CS1 at a position closer to the inner peripheral edge 24 than the outer peripheral end 23 of the blade 20, the distance between the maximum extreme point 33 in the direction perpendicular to the chord 30 and the chord 30 is defined as "distance H ｈ " is defined as

[0073] Regarding the camber height H, as shown in FIG. 14, in the chord direction cross section CS2 at a position closer to the outer peripheral end 23 than the inner peripheral edge 24 of the blade 20, the distance between the maximum extreme point 33 in the direction perpendicular to the chord 30 and the chord 30 is defined as "distance H ｔ " is defined as

[0074] The impeller 10 is spaced apart by a distance H ｔ is the distance H ｈ That is, the impeller 10 is formed so that the distance Hｈ <distance H ｔ The gyro is formed so as to satisfy the relationship:

[0075] [Effects of Impeller 10] As described above, the magnitude of the rotational component of the airflow passing through the leading edge of the blade is proportional to the radius, so the magnitude of the rotational component of the airflow passing through the leading edge of the blade on the outer peripheral end side is greater than the magnitude of the rotational component of the airflow passing through the leading edge of the blade on the inner peripheral edge side. Furthermore, when the chord-direction cross section CS is defined, the area of ​​multiple cylindrical cross sections of the blade 20 centered on the rotation axis 11 is proportional to the radius at a constant axial height, so the blade chord length can be increased from the inner peripheral edge 24 to the outer peripheral edge 23.

[0076] By increasing the chord length of the impeller 10, the air volume at the same rotation speed can be increased. ｈ <distance H ｔ By satisfying the relationship, the static pressure can be further increased on the outer circumferential side of the blades 20 where the magnitude of the airflow is greater than on the inner circumferential side, compared to a configuration that does not have this configuration. Therefore, the impeller 10 can increase the air volume at the same rotation speed of the blades 20, compared to a configuration that does not have this configuration. Therefore, the impeller 10 can achieve higher fan efficiency, compared to a configuration that does not have the above configuration.

[0077] Embodiment 4. Figure 15 is a conceptual diagram showing a cross section of blower 100 according to embodiment 4, taken along an arbitrary plane parallel to and passing through rotation axis 11 of blower 100 shown in Figure 1. Blower 100 according to embodiment 4 will be described with reference to Figure 15 and the already shown Figure 1. Note that components having the same functions and actions as those in embodiments 1 to 3 are designated by the same reference numerals, and description thereof will be omitted.

[0078] Blower 100 according to the fourth embodiment includes casing 80 having a bell mouth 81, and impeller 10 according to any one of the first to third embodiments housed inside casing 80. In other words, blower 100 according to the fourth embodiment includes casing 80 having a bell mouth 81, and impeller 10 according to any one of the first to third embodiments arranged on the inner circumferential side of bell mouth 81 when viewed in the axial direction of rotating shaft 11.

[0079] The casing 80 is formed in a box shape to house the impeller 10 inside. The casing 80 has a substantially cylindrical bell mouth 81 on each of the air blowing side and the air suction side. The bell mouth 81 is shaped such that, for example, in the axial direction of the rotating shaft 11, the distance from the rotating shaft 11 increases with increasing distance from the center of the casing 80. In other words, the casing 80 is shaped such that, for example, in the axial direction of the rotating shaft 11, the distance from the rotating shaft 11 increases with increasing distance from the center of the casing 80 due to the bell mouth 81.

[0080] The bell mouth 81 and the casing 80 are not limited to the above shapes, and may have any shape as long as the distance from the rotating shaft 11 does not decrease with increasing distance from the center of the casing 80 in the axial direction of the rotating shaft 11. In other words, the casing 80 may have a cylindrical overall shape.

[0081] In Figure 15, an example of a trajectory of the blades 20 when rotated is shown as the impeller 10. Also, the impeller 10S drawn by the dotted line in Figure 15 indicates the limit position of the range in which the effect of the impeller 10 can be obtained when the impeller 10 is moved in each direction of the air blowing side and the air suction side.

[0082] Here, the length of the casing 80 in the axial direction of the rotary shaft 11 is defined as a length H ｂ When the casing 80 is installed so that the rotating shaft 11 is in the vertical direction, the length H of the casing 80 is ｂ is the height of the casing 80.

[0083] As shown in FIG. 15, the impeller 10 has a length εH ｂ The effect of the impeller 10 can be exhibited in the region inside the imaginary plane SF, which is separated from the casing 80 by 100 mm. In this case, the coefficient ε may be greater than 0 and not more than 0.5 (0<ε≦0.5). That is, the impeller 10 has a length εH ｂ The sensor 10 is disposed in an area inside an imaginary plane SF located at a distance of .mu.m from the casing 80.

[0084] [Operation and Effect of Fan 100] As shown in FIG. 15, the fan 100 has a length εH ｂ The effects of impeller 10 can be exerted by disposing impeller 10 in a region inside the surface that is distant from casing 80 by only a small amount. With the above-described configuration, blower 100 according to embodiment 4 can obtain a blower that can improve the fan efficiency of impeller 10 and increase the air volume at the same rotation speed without changing the size.

[0085] Embodiment 5. Figure 16 is a perspective view showing the configuration of an air conditioner 200 pertaining to embodiment 5. The air conditioner 200 pertaining to embodiment 5 will be described with reference to Figure 16. Note that components having the same functions and actions as those in embodiments 1 to 4 are given the same reference numerals and their description will be omitted. In embodiment 5, an outdoor unit of a multi-air conditioner for a building is shown as an example of the air conditioner 200, but the air conditioner 200 is not limited to an outdoor unit of a multi-air conditioner for a building.

[0086] 16, air conditioner 200 has impeller 10 according to any one of embodiments 1 to 3 and blower 100 according to embodiment 4 that is equipped with the impeller 10. Air conditioner 200 also has a housing 203. Air conditioner 200 also has a heat exchanger 204 that exchanges heat between air supplied by impeller 10 inside housing 203 and a refrigerant circulating therein.

[0087] 16, the housing 203 is formed in a box shape, for example, in a rectangular parallelepiped shape. However, the shape of the housing 203 is not limited to a rectangular parallelepiped. An air outlet 202 is formed in the upper part of the housing 203 for discharging the outdoor air drawn into the housing 203 to the outside of the air conditioner 200 of the housing 203.

[0088] Intake ports 201 are formed on each side surface of housing 203 to draw outside air into housing 203. Intake ports 201 may be formed on all four side surfaces of housing 203, or may be formed on one or more of the four surfaces rather than on all four surfaces. Intake ports 201 may also be formed on a portion of the side surface of housing 203, or may be formed on the entire side surface.

[0089] Inside the housing 203, a blower 100 and a heat exchanger 204 are provided in an air passage extending from the air inlet 201 to the air outlet 202. The blower 100 is disposed upstream of the air outlet 202 and downstream of the heat exchanger 204 in the direction of the air flow formed by the blower 100. The heat exchanger 204 exchanges heat between the outdoor air and the refrigerant flowing inside the heat exchanger 204 to produce conditioned air.

[0090] In the air conditioner 200, when the impeller 10 of the blower 100 rotates, outdoor air is drawn into the interior of the housing 203 through the air inlet 201. As this outdoor air passes through the heat exchanger 204, it is heated or cooled by heat exchange with the refrigerant to become conditioned air. The conditioned air that has undergone this heat exchange is blown out from the air outlet 202 to the area to be conditioned.

[0091] [Effects of air conditioner 200] As described above, blower 100 has higher efficiency and a larger air volume than conventional impellers without changing the size of the impeller. Therefore, air conditioner 200 according to embodiment 5 can improve power efficiency and operate at a larger air volume than conventional air conditioners having a blower other than blower 100, without increasing the dimensions of air conditioner 200.

[0092] As described above, the air conditioner 200 according to the fifth embodiment includes the impeller 10 according to any one of the first to third embodiments, and a heat exchanger 204 that exchanges heat between the air supplied by the impeller 10 and the refrigerant circulating therein. According to this configuration, the air conditioner 200 includes the impeller 10, and therefore, compared to conventional air conditioners that include an impeller other than the impeller 10, the air conditioner 200 can be operated at a large air volume and with improved power efficiency without increasing the dimensions of the air conditioner 200.

[0093] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, and parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0094] 10 Impeller, 10S Impeller, 11 Rotating shaft, 12 Boss portion, 12a Boss midpoint, 20 Blade, 21 Leading edge portion, 22 Trailing edge portion, 23 Outer peripheral end portion, 23a Outer peripheral front end portion, 23b Outer peripheral rear end portion, 24 Inner peripheral edge portion, 24a Inner peripheral front end portion, 24b Inner peripheral rear end portion, 25 Pressure surface, 26 Suction surface, 27 Span line, 27a Span line, 27b Span line, 27c Span line, 28 Intermediate portion, 29 Trailing edge side recess, 30 Blade chord, 31 Camber line, 32 Inflection point, 33 Maximum extreme point, 34 Camber midpoint, 35 Blade surface, 40 Boss midsection, 80 Casing, 81 Bell mouth, 100 Blower, 200 Air conditioner, 201 Intake port, 202 Air outlet, 203 housing, 204 heat exchanger, CD double arrow, CL cylinder, CS cord direction cross section, CS1 cord direction cross section, CS2 cord direction cross section, F thick arrow, FA arrow, H height, H ｈ distance, H ｔ Distance, P virtual point, R thick arrow, SF virtual surface, SS spanwise cross section, Sh trailing edge wing height, r distance, r1 distance, r2 distance.

Claims

1. A rotor comprising a boss portion provided on a rotation shaft, and a plurality of blades provided on an outer periphery of the boss portion, each of the plurality of blades having a leading edge portion which is the edge on the front side in the direction of rotation, a trailing edge portion which is the edge on the rear side in the direction of rotation, an outer peripheral end portion which is the edge on the outer periphery, and an inner peripheral edge portion which is the edge on the inner periphery, wherein, assuming a plurality of imaginary cylinders centered on the rotation shaft, each imaginary cross section of the plurality of blades corresponding to a cylindrical portion is defined as a chord direction cross section, a straight line connecting the leading edge portion and the trailing edge portion in the chord direction cross section is defined as a chord, and a center line of the blade cross section is defined as a camber line, a distance between the camber line and the chord in a direction perpendicular to the chord in the chord direction cross section is defined as a camber height, a position on the camber line where the distance from the leading edge portion is equal to that from the trailing edge portion is defined as a camber midpoint, and a point on the camber line where the camber height is maximum is defined as a maximum extreme point, the maximum extreme point is located closer to the trailing edge than the camber midpoint and on the air suction side than the chord, and the camber line has at least one inflection point between the leading edge and the maximum extreme point; and the impeller, the maximum extreme point is located closer to the leading edge than the camber midpoint and on the air suction side than the chord, in the chord cross section at a position closer to the outer circumferential edge than the inner circumferential edge of the blade.

2. An impeller as claimed in claim 1, wherein the camber line is formed so as to be located on the air suction side of the blade chord over the entire area of ​​the blade in the radial direction of the rotating shaft.

3. In the chord direction cross section at a position closer to the inner circumferential edge than the outer circumferential end of the blade, the distance between the maximum extreme point and the chord in a direction perpendicular to the chord is defined as a distance H ｈ In the chord direction cross section at a position closer to the outer circumferential end portion than the inner circumferential edge portion of the blade, the distance between the maximum extreme point and the chord in a direction perpendicular to the chord is defined as a distance H ｔ When the distance H is defined as ｈ <distance H ｔ 3. The impeller according to claim 1, which is formed so as to satisfy the relationship:

4. A compressor comprising: a casing having a bell mouth; and an impeller according to any one of claims 1 to 3 housed inside the casing; and wherein the length of the casing in the axial direction of the rotating shaft is defined as length H. ｂ and the coefficient ε is defined as 0<ε≦0.5, the impeller has the length εH ｂ The blower is disposed in a region inside an imaginary plane located at a position away from the casing by a distance of 1 mm.

5. An air conditioner comprising: an impeller according to any one of claims 1 to 3; and a heat exchanger for exchanging heat between air supplied by the impeller and a refrigerant circulating therethrough.

Images