Impeller, blower, and air conditioner

Abstract

This impeller comprises a boss section provided on a rotary shaft and blades provided on the outer circumference of the boss section. The blades have a front edge section that is a frontward edge in the rotation direction, a rear edge section that is a rearward edge in the rotation direction, an outer circumferential end section that is an edge on the outer circumferential side, and an inner circumferential end section that is an edge on the inner circumferential side. In a chord-direction cross section defined as a cross section obtained by cutting the blades by means of a cylinder with the rotation axis serving as the center, a line segment connecting the front edge section and the rear edge section is defined as a blade chord, an angle formed by the rotation shaft and the blade chord is defined as a stagger angle, the stagger angle is positive when the rear edge section of the blades is inclined toward a negative pressure surface side of the blades, the chord-direction cross section includes a first chord-direction cross section and a second chord-direction cross section further circumferentially outward than the first chord-direction cross section, the stagger angle of the blades decreases from the inner circumferential end section to the first chord-direction cross section, and the stagger angle of the blades increases from the first chord-direction cross section to the second chord-direction cross section.

Description

Impeller, blower, and air conditioner

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

[0002] The efficiency of an impeller is improved by blowing air across the entire impeller. For example, Patent Document 1 discloses an impeller in which the stagger angle decreases from the inner periphery to the outer periphery, so that the blades are more upright. The stagger angle is the angle of the blade chord relative to the direction of the rotation axis.

[0003] Japanese Patent Application Laid-Open No. 2001-174022

[0004] In Patent Document 1, the stagger angle decreases from the inner circumferential side to the outer circumferential side in the radial direction so that the blades stand up toward the outer circumferential end of the blades. In this case, the airflow does not flow along the blades on the outer circumferential side of the blades, resulting in a decrease in airflow efficiency. Therefore, there is a need to improve the efficiency of the entire impeller.

[0005] An object of the present disclosure is to provide an impeller, a blower, and an air conditioner with high efficiency.

[0006] An impeller according to the present disclosure includes a boss portion provided on a rotation shaft and blades provided on an outer periphery of the boss portion, and the blades have a leading edge portion that is an edge forward in a rotation direction, a trailing edge portion that is an edge rearward in the rotation direction, an outer peripheral end portion that is an edge on an outer periphery, and an inner peripheral end portion that is an edge on an inner periphery, and a cross section of the blade obtained by cutting the blade with a cylinder centered on the rotation shaft is defined as a chord direction cross section, and a line segment connecting the leading edge and the trailing edge in the chord direction cross section is defined as a blade chord, and an angle formed between the rotation shaft and the blade chord is defined as a stagger angle, and an angle of the stagger angle inclined toward the suction surface of the blade is defined as a positive angle, and the chord direction cross sections include a first chord direction cross section and a second chord direction cross section that is outer than the first chord direction cross section, and the stagger angle of the blade decreases from the inner peripheral end portion to the first chord direction cross section and increases from the first chord direction cross section to the second chord direction cross section.

[0007] Furthermore, the blower according to the present disclosure comprises the above-mentioned impeller and a casing having a bell mouth surrounding the impeller from the radial outside, and when the height of the casing is Hb and ε is 0.5, the impeller is surrounded within imaginary planes that are axially spaced εHb from the suction side and the blowing side of the casing, respectively.

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

[0009] In the impeller, blower, and air conditioner according to the present disclosure, the stagger angle of the impeller blades decreases from the inner circumferential end to the outer circumferential end and then increases, thereby improving the work done on the inner circumferential side of the blades and allowing air to flow without loss on the outer circumferential side of the blades, thereby achieving high efficiency throughout the impeller.

[0010] FIG. 1 is a perspective view of a blower according to a first embodiment of the present disclosure; FIG. 2 is a projection view in a plane perpendicular to the rotation axis of the impeller according to the first embodiment of the present disclosure; FIG. 3 is a schematic view illustrating a stagger angle of blades according to the first embodiment of the present disclosure; FIG. 4 is a schematic view illustrating a stagger angle at an inner circumferential end of the impeller according to the first embodiment of the present disclosure; FIG. 5 is a schematic view illustrating a stagger angle in a first chord cross section of the impeller according to the first embodiment of the present disclosure; FIG. 6 is a schematic view illustrating a stagger angle in a second chord cross section of the impeller according to the first embodiment of the present disclosure; FIG. 7 is a graph showing the relationship between flow rate and efficiency obtained with the impeller according to the first embodiment of the present disclosure; FIG. 8 is a projection view in a plane perpendicular to the rotation axis of the impeller according to the second embodiment of the present disclosure; FIG. 9 is a perspective view of the impeller according to the second embodiment of the present disclosure; FIG. 10 is a projection view in a plane perpendicular to the rotation axis of the impeller according to the third embodiment of the present disclosure; FIG. 11 is a perspective view of the impeller according to the third embodiment of the present disclosure; FIG. 12 is a schematic view illustrating a stagger angle at an inner circumferential end of the impeller according to the fourth embodiment of the present disclosure; FIG. 10 is a schematic diagram illustrating a stagger angle in a cross section in a first chord direction of an impeller according to a fourth embodiment of the present disclosure. FIG. 11 is a schematic diagram illustrating a stagger angle in a cross section in a second chord direction of an impeller according to the fourth embodiment of the present disclosure. FIG. 12 is a projection view on a plane perpendicular to the rotation axis of impellers according to the fourth embodiment of the present disclosure, stacked in the direction of the rotation axis. FIG. 13 is a cross-sectional view showing a blower according to a fifth embodiment of the present disclosure. FIG. 14 is a perspective view of an air conditioner according to a sixth embodiment of the present disclosure.

[0011] The embodiments of the present disclosure will be described with reference to the accompanying drawings. In each drawing, identical or corresponding parts are designated by the same reference numerals, and redundant descriptions are appropriately simplified or omitted. In the following description, for convenience, the positional relationship of each structure may be expressed based on the illustrated state. Note that the present disclosure is not limited to the following embodiments. Free combinations of the embodiments, modifications of any of the components of each embodiment, or omission of any of the components of each embodiment are possible within the scope of the present disclosure. Furthermore, in each drawing, the dimensional relationships or shapes of each component may differ from the actual ones. Furthermore, the positional relationships between components, such as the vertical relationship, are generally those when the device is installed in a usable state. However, for ease of understanding, terms indicating directions, such as "up," "down," "right," "left," "front," and "rear," are used as appropriate. However, these terms are used as appropriate for ease of explanation and do not limit the arrangement or orientation of the device or components. Furthermore, although chamfering is not performed in the following drawings, similar effects can be achieved even if chamfering is performed. That is, for example, whether C-chamfering or R-chamfering is performed, the same effect can be obtained.

[0012] Embodiment 1. Fig. 1 is a perspective view showing a blower 100 according to embodiment 1 of the present disclosure. Fig. 2 is a projection view of an impeller 10 according to embodiment 1 of the present disclosure on a plane perpendicular to the rotation shaft 11. Figs. 1 and 2 show the configuration of the blower 100 as viewed from the suction side, i.e., the pressure surface 25 side of the blades 20. In Figs. 1 and 2 and the drawings described below, the thick black arrows indicate 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, in Figs. 1 and 2 and the drawings described below, the thick white arrows indicate the overall direction of airflow when the impeller 10 rotates. The blower 100 according to embodiment 1 is an axial flow blower that blows air in a direction along the rotation shaft 11.

[0013] 1 and 2, blower 100 has a casing 80 and an impeller 10. Casing 80 has a substantially cylindrical bell mouth 81. Impeller 10 is disposed on the inner circumferential side of bell mouth 81. Impeller 10 is provided so as to be rotatable about a rotation shaft 11. Blower 100 also has a drive unit (not shown), such as a motor, that rotates impeller 10.

[0014] The impeller 10 has a boss 12 provided on a rotary shaft 11 and a plurality of blades 20 provided on the outer periphery of the boss 12. The boss 12 has a substantially cylindrical shape. A drive shaft (not shown) provided in a drive unit is connected to the center of the boss 12. The boss 12 rotates around the rotary shaft 11 by receiving a rotational driving force from the drive unit via the drive shaft.

[0015] The plurality of blades 20 are arranged at approximately equal angular intervals on the outer periphery of the boss portion 12. Each of the plurality of blades 20 protrudes approximately radially from the outer periphery wall 121 of the boss portion 12. More specifically, each of the plurality of blades 20 protrudes outward from the outer periphery wall 121 of the boss portion 12 so as to be inclined forward in the rotation direction of the impeller 10 with respect to the radial direction centered on the rotation shaft 11. Although the figure illustrates an impeller 10 having three blades 20, the number of blades 20 that the impeller 10 has may be other than three.

[0016] Each of the multiple blades 20 has a leading edge 21, a trailing edge 22, an outer peripheral end 23, and an inner peripheral end 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 that is outer peripheral. The inner peripheral end 24 is the edge of the periphery of the blade 20 that is inner peripheral. The inner peripheral end 24 has a shape that follows the outer peripheral wall 121 of the boss portion 12 and is connected to the outer peripheral wall 121.

[0017] The outer peripheral end 23 and the leading edge 21 are adjacent to each other via an outer peripheral leading end 23a. The outer peripheral end 23 and the trailing edge 22 are adjacent to each other via an outer peripheral trailing end 23b. The inner peripheral end 24 and the leading edge 21 are adjacent to each other via an inner peripheral leading end 24a. The inner peripheral end 24 and the trailing edge 22 are adjacent to each other via an inner peripheral trailing end 24b.

[0018] Each of the multiple blades 20 has a pressure surface 25 and a suction surface 26 (see FIG. 3 , etc.). The pressure surface 25 is the front surface of the two surfaces that the blade 20 has in the direction of rotation. When the blade 20 rotates, the air is pushed by the pressure surface 25. The suction surface 26 is the rear surface of the two surfaces that the blade 20 has in the direction of rotation, and is the surface behind the pressure surface 25. Note that, because FIGS. 1 and 2 show the configurations of the blower 100 and the impeller 10, respectively, as seen from the pressure surface 25 side, the suction surface 26 is not shown in FIGS. 1 and 2 .

[0019] The plurality of blades 20 rotate together with the boss portion 12 around the rotation shaft 11. When the plurality of blades 20 rotate, air is drawn into the blower 100 along the rotation shaft 11 from the rear side of the page, as shown by the thick white arrow in Figure 1. The air drawn into the blower 100 is blown out from the blower 100 along the rotation shaft 11 to the front side of the page.

[0020] Here, multiple cylindrical cross sections of the blade 20 centered on the rotation axis 11 are defined as chord direction cross sections. The chord direction cross sections include, for example, a first chord direction cross section 41 and a second chord direction cross section 42 that is closer to the rotation axis 11 than the first chord direction cross section 41. In other words, any cross sections among the chord direction cross sections are referred to as the first chord direction cross section 41 and the second chord direction cross section 42 in order of proximity to the rotation axis 11.

[0021] In the following description, the distance from the rotary shaft 11 to the inner peripheral end 24 is r ｂ The distance from the rotation axis 11 to the outer peripheral end 23 is r ｔ The distance from the rotary shaft 11 to the first chord direction cross section 41 is r ｄ and the distance from the rotary shaft 11 to the second chord direction cross section 42 is αr ｄ where α is a constant.

[0022] 3 is a schematic diagram illustrating the stagger angle 31 of the blade 20 according to the first embodiment of the present disclosure, showing an arbitrary chord direction cross section. In FIG. 3, the up-down direction represents the direction along the rotation axis 11, the lower side represents the suction side, and the upper side represents the blowing side.

[0023] As shown in Fig. 3, the line segment connecting the leading edge 21 and the trailing edge 22 is the chord 30, and the angle between the rotation axis 11 and the chord 30 is the stagger angle 31. The stagger angle 31 is positive when the trailing edge 22 of the blade 20 is inclined toward the suction surface 26. Note that Fig. 3 shows a typical blade 20 to simplify the explanation of the stagger angle 31 of the blade 20, and that this differs from the blade 20 that constitutes the impeller 10 of the present disclosure. For example, the blade 20 may be flatter than shown, or may be curved into a shape having one or more inflection points.

[0024] Figure 4 is a schematic diagram illustrating the stagger angle 31 at the inner circumferential end 24 of the impeller 10 according to the first embodiment of the present disclosure. Figure 5 is a schematic diagram illustrating the stagger angle 31 at a first chord cross section 41 of the impeller 10 according to the first embodiment of the present disclosure. Figure 6 is a schematic diagram illustrating the stagger angle 31 at a second chord cross section 42 of the impeller 10 according to the first embodiment of the present disclosure.

[0025] 4 to 6, each of the plurality of blades 20 has a shape in which the stagger angle 31 decreases from the inner circumferential end 24 to the first chord cross section 41, and then increases from the first chord cross section 41 to the second chord cross section 42. For example, the stagger angle 31 monotonically decreases from the inner circumferential end 24 to the first chord cross section 41, and then monotonically increases from the first chord cross section 41 to the second chord cross section 42.

[0026] For example, the stagger angle 31 is configured to constantly decrease from the inner circumferential end 24 to the first cord direction cross section 41 and constantly increase from the first cord direction cross section 41 to the second cord direction cross section 42. For example, the stagger angle 31 may decrease more rapidly or more slowly in a portion from the inner circumferential end 24 to the first cord direction cross section 41 than in other portions. Furthermore, the stagger angle 31 may increase more rapidly or more slowly in a portion from the first cord direction cross section 41 to the second cord direction cross section 42 than in other portions.

[0027] The stagger angle 31 monotonically increases, for example, from the second chord cross section 42 toward the outer peripheral end 23 of the blade 20. The stagger angle 31 from the second chord cross section 42 to the outer peripheral end 23 may be any value.

[0028] As described above, the blades 20 of the impeller 10 are configured such that the stagger angle 31 of the blades 20 decreases from the inner circumferential end 24 to the first chord cross section 41 and increases from the first chord cross section 41 to the second chord cross section 42. That is, at the first chord cross section 41, the stagger angle 31 takes on a minimum value in the range from the inner circumferential end 24 to the second chord cross section 42.

[0029] The stagger angle 31 of the blade 20 constantly decreases from the inner circumferential end 24 to the first chord cross section 41. That is, the stagger angle 31 at the first chord cross section 41 is smaller than the stagger angle 31 at the inner circumferential end 24. By enlarging the chord 30 of the blade 20 at the first chord cross section 41, the work performed by the blade 20 in the vicinity of the first chord cross section 41 is increased. As a result, the work performed at the inner circumferential end 24 side of the blade 20 from the inner circumferential end 24 to the outer circumferential end 23 can be increased, enabling the efficiency of the blower 100 to be improved.

[0030] Furthermore, the stagger angle 31 of the blade 20 constantly increases from the first chord cross section 41 to the second chord cross section 42. The magnitude of the rotational component of the airflow passing through the leading edge 21 of the blade 20 is proportional to the distance from the rotation axis 11, and is therefore smaller on the inner circumferential end 24 side and larger on the outer circumferential end 23 side. If the magnitude of the component of the airflow passing through the leading edge 21 of the blade 20 along the rotation axis 11 is constant, the angle between the airflow and the rotation axis 11 increases from the inner circumferential end 24 to the outer circumferential end 23.

[0031] Therefore, by increasing the stagger angle 31 of the blades 20 from the first chord cross section 41 to the second chord cross section 42, the airflow that has passed the leading edge 21 side flows along the blades 20, and separation is suppressed, thereby achieving high efficiency. In this way, work is improved on the inner circumferential end 24 side of the blades 20, and air can be passed without loss on the outer circumferential end 23 side, so the overall air blowing efficiency of the impeller 10 can be improved.

[0032] Here, the position of the first chord direction cross section 41 is r ｂ <r ｄ ≦0.5r ｔ The first chord direction cross section 41 is located, for example, near the position of the inner circumferential end 24, which is the connection between the boss portion 12 and the blade 20. In the impeller 10, the boss portion 12 has a radius of, for example, 0.5r at most. ｔ From the above, the position of the first chord direction cross section 41 is r ｂ <r ｄ ≦0.5r ｔ is set so that

[0033] The position of the second chord direction cross section 42 is αr ｄ and is set so that, for example, α=1.01 holds. α may be a very small amount, for example, α=1.001, and more preferably, α=1.000001.

[0034] By appropriately setting the positions of the first chord cross section 41 and the second chord cross section 42, it is possible to reduce the stagger angle 31 of the blades 20 on the inner circumferential end 24 side of the blades 20. This allows the airflow sucked into the impeller 10 to flow along the blades 20, thereby making it possible to obtain a highly efficient impeller 10.

[0035] The distance from the inner circumferential end 24 to the first chord direction cross section 41 is normalized by the distance from the rotary shaft 11 to the outer circumferential end 23, and the normalized value is (r ｄ -r ｂ ) / r ｔ (r ｄ -r ｂ ) / r ｔ The gradient Δγ / Δr, which is the ratio of the increment of the stagger angle 31 to the increment of the stagger angle 31, may be Δγ / Δr<−π / 2, and more preferably Δγ / Δr<0. By setting it in this manner, it is possible to increase the work done on the inner peripheral end 24 side of the blade 20 without expanding the boss portion 12 in the direction of the rotation axis 11, and to further achieve the effect of increasing the efficiency of the blade 20.

[0036] Fig. 7 is a graph showing the relationship between efficiency and air volume obtained with the impeller 10 according to the first embodiment of the present disclosure. As a comparative example, Fig. 7 also shows the relationship between efficiency and air volume obtained with the impeller 10 of a general axial flow fan. In Fig. 7, an example shows the relationship between efficiency and air volume when the impeller 10 according to the first embodiment is used. As shown in Fig. 7, the impeller 10 of the example has improved efficiency compared to the comparative example.

[0037] In the typical axial flow fan of the comparative example, the efficiency of the impeller 10 is improved by blowing airflow over the entire impeller 10. More specifically, the efficiency of the impeller 10 is improved by having the blades 20 near the rotating shaft 11, where torque is small, do work and reducing the load on the blades 20 near the outer circumferential ends 23 of the blades 20. In order to increase the work of the blades 20 near the rotating shaft 11, it is necessary to increase the length of the chord 30 while suppressing the stagger angle 31 of the blades 20.

[0038] For example, as a comparative example, an impeller 10 has been proposed in which multiple blades 20 are joined at their bases and the joined area is shaped to blow air as the blades rotate, thereby enabling forward airflow even near the center of rotation of the blades 20 and improving airflow capacity. In this type of impeller 10, unless the boss portion 12 is expanded in the direction of the rotation axis 11, it is not possible to further improve the work of the blades 20 near the rotation axis 11. In other words, it is not possible to increase the work on the inner circumferential end 24 side of the blades 20, and improvement in the efficiency of the impeller 10 cannot be expected. In contrast, the impeller 10 according to embodiment 1 increases the work on the inner circumferential end 24 side of the blades 20, thereby making it possible to improve the efficiency of the blades 20.

[0039] As described above, the impeller 10 according to the first embodiment has a configuration in which the stagger angle 31 of the blades 20 decreases from the inner circumferential end 24 to the first chord cross section 41 and increases from the first chord cross section 41 to the second chord cross section 42. This improves the work done on the inner circumferential side of the blades 20 and allows the airflow to flow without loss on the outer circumferential side of the blades 20. Furthermore, by reducing the stagger angle 31 at the inner circumferential end 24, the blade chord 30 can be increased toward the first chord cross section 41, increasing the work done by the blades 20 and achieving high efficiency. Furthermore, by increasing the stagger angle 31 from the first chord cross section 41 to the second chord cross section 42, the airflow that has passed the leading edge 21 flows along the blades 20, suppressing separation at the outer circumferential end 23 of the blades 20 and achieving high efficiency. In this way, it is possible to achieve high efficiency for the entire impeller 10 while suppressing the increase in the size of the boss portion 12.

[0040] Furthermore, the distance from the rotary shaft 11 to the first chord cross section 41 is equal to or less than half the distance from the rotary shaft 11 to the outer peripheral end 23. Furthermore, the distance from the rotary shaft 11 to the second chord cross section 42 is α times the distance from the rotary shaft 11 to the outer peripheral end 23, where α is, for example, 1.01. By setting the distances in this manner, the stagger angle 31 of the blades 20 on the inner peripheral end 24 side of the blades 20 is reduced, and the airflow sucked into the impeller 10 can flow along the blades 20, thereby achieving a highly efficient impeller 10.

[0041] Second Embodiment Figure 8 is a projection view of an impeller 10 according to a second embodiment of the present disclosure, taken on a plane perpendicular to the rotation shaft 11. The impeller 10 according to the second embodiment differs from the first embodiment in that it includes a drainage portion 50. In the second embodiment, parts common to the first embodiment are denoted by the same reference numerals and description thereof will be omitted, and the following description will focus on the differences from the first embodiment. As shown in Figure 8, the drainage portion 50 is provided in the leading edge portion 21 of the blade 20 in the first chord direction cross section 41.

[0042] 9 is a projection view of an impeller 10 according to a second embodiment of the present disclosure, taken on a plane parallel to the rotation shaft 11. As shown in FIG. 9 , the drainage point 50 is located on the suction side in the range from the inner circumferential end 24 to the second chord cross section 42, i.e., on the first chord cross section 41.

[0043] Specifically, the blade 20 has a configuration in which the stagger angle 31 decreases from the inner circumferential end 24 to the first chord cross section 41 and increases from the first chord cross section 41 to the second chord cross section 42, and the water discharge point 50 is located on the suction side. The water discharge point 50 is a portion recessed toward the suction surface 26, and its deepest portion is located on the first chord cross section 41. In other words, the water discharge point 50 is located at the leading edge 21 at a position r away from the rotation axis 11. ｄ is located at a distance of

[0044] Fig. 10 is a perspective view of impeller 10 according to the second embodiment of the present disclosure. As shown in Fig. 10, when impeller 10 is operated so as to blow out airflow vertically upward, rain or dust that falls around drainage point 50 follows a trajectory of drainage flow path 51 and is guided to drainage point 50. In this way, providing drainage point 50 on impeller 10 enables improved drainage performance.

[0045] Generally, the impeller 10 is composed of a cylindrical boss 12 and blades 20 attached to the outer periphery of the boss 12. The efficiency of the impeller 10 is improved by blowing air using the entire impeller 10. Because the boss 12 of the impeller 10 does not contribute to airflow, the blowing performance of the impeller 10 can be improved by reducing the size of the boss 12 and enlarging the blades 20. However, when the impeller 10 is installed to blow air vertically upward, the boss 12 also serves to protect structures disposed vertically downward, such as a driving unit (not shown) such as a motor, from rain and dust. Therefore, an impeller 10 having a boss 12 with a small diameter perpendicular to the rotation axis 11 cannot be used, and improvement in the efficiency of the impeller 10 cannot be expected.

[0046] The impeller 10 of the second embodiment is configured so that the entire blade 20 from the outer circumferential end 23 of the blade 20 to the center of the rotary shaft 11 performs work, and furthermore has a drainage portion 50. This makes it possible to employ a boss portion 12 with a small diameter, thereby achieving both high efficiency of the impeller 10 and improved drainage.

[0047] If the impeller 10 is installed so as to blow air vertically upward and the motor is disposed vertically downward, rain discharged from the leading edge 21 of the blade 20 when the impeller 10 is stopped may turn into icicles in an environment below freezing. In this case, if the icicles connect with the motor, the impeller 10 and the motor may be locked when the operation starts, preventing rotation. Therefore, the position of the drainage point 50, i.e., r ｄ It is more preferable that r is a value larger than that of the upstream structure. For example, if the upstream structure is a motor, r ｄ is preferably greater than the outer radius of the motor.

[0048] With this configuration, rain that could turn into icicles passes through the drainage flow path 51 and is drained from the drainage point 50, preventing icicles from forming at the drainage point 50 and connecting the blades 20 to the motor. In other words, with this configuration, the impeller 10 and the motor will not be locked by icicles.

[0049] As described above, in the impeller 10 according to the second embodiment, the drainage point 50 is provided at a position closest to the suction side within the range from the inner circumferential end 24 to the second chord direction cross section 42. This makes it possible to achieve both high efficiency by having the entire blade 20, from the outer circumferential end 23 of the blade 20 to the rotating shaft 11, perform work, and improved drainage.

[0050] Embodiment 3. Figure 11 is a projection view of an impeller 10 according to embodiment 3 of the present disclosure on a plane perpendicular to the rotation axis 11. Figure 12 is a perspective view of the impeller 10 according to embodiment 3 of the present disclosure. The impeller 10 according to embodiment 3 differs from embodiments 1 and 2 in the configuration of the plurality of blades 20. In embodiment 3, parts common to embodiments 1 and 2 are assigned the same reference numerals and description thereof will be omitted, and the following description will focus on the differences from embodiments 1 and 2.

[0051] 11 and 12, the blades 20 of the impeller 10 are connected to adjacent blades 20 over the entire area from the inner circumferential end 24 to the third chord cross section 43. The third chord cross section 43 is located at a distance r from the rotary shaft 11. ｓ In this case, r ｂ <r ｓ <r ｄ The blades 20 are connected to adjacent blades 20 from the inner circumferential end 24 to the third chord cross section 43 .

[0052] At any chord cross section from the inner circumferential end 24 to the third chord cross section 43, adjacent blades 20 have a stagger angle 31. That is, the blades 20 have an arbitrary inclination with respect to the rotation axis 11. Also, the blades 20 always have an arbitrary thickness. Therefore, at any chord cross section, a step 205 is formed at the connection between adjacent blades 20. The step 205 is formed from the inner circumferential end 24 to the third chord cross section 43 toward the drainage point 50.

[0053] Therefore, when the impeller 10 is operated so as to blow out airflow vertically upward, rain or dust that falls on the inner circumferential end 24 and its surroundings is discharged to the drainage point 50 via the step 205. This further improves drainage. Even if the edge portion of the step 205 is R-chamfered or C-chamfered, it can still serve as the drainage flow path 51, and the same effect can be obtained.

[0054] The step 205 is formed from the inner circumferential end 24 to the third chord direction cross section 43, so as to extend from the rotary shaft 11 toward the outer circumferential end 23. Therefore, the third chord direction cross section 43 may be located between the inner circumferential end 24 and the first chord direction cross section 41. ｂ <r ｓ <r ｄ holds true.

[0055] The blades 20 and the boss portion 12 are smoothly connected, for example, at the upper and lower surfaces of the boss portion 12. The boss portion 12 and the blades 20 do not necessarily have to be smoothly connected, and other configurations are possible. That is, the boss portion 12 may have, for example, a substantially cylindrical shape with a height in the direction of the rotation shaft 11. By smoothly connecting the boss portions 12, the height of the boss portion 12 along the rotation shaft 11 is approximately the thickness of the blades 20, and the height of the boss portion 12 can be reduced.

[0056] According to the impeller 10 according to the third embodiment described above, adjacent blades 20 of the impeller 10 are connected from the inner circumferential end 24 to the third chord cross section 43. In other words, adjacent blades 20 are connected over the entire area from the inner circumferential end 24 to the third chord cross section 43. As a result, air is blown in conjunction with rotation in the area where multiple blades 20 are joined, and forward air can be blown even near the center of rotation of the blades 20, improving air blowing capacity. Furthermore, the blades 20 have a stagger angle 31 from the inner circumferential end 24 to the third chord cross section 43, and steps 205 are formed at the connections between adjacent blades 20. These steps 205 serve as drainage channels 51, improving drainage.

[0057] Fourth Embodiment Figure 13 is a schematic diagram illustrating the stagger angle 31 at the inner circumferential end 24 of the impeller 10 according to a fourth embodiment of the present disclosure. Figure 14 is a schematic diagram illustrating the stagger angle 31 at a first chord cross section 41 of the impeller 10 according to the fourth embodiment of the present disclosure. Figure 15 is a schematic diagram illustrating the stagger angle 31 at a second chord cross section 42 of the impeller 10 according to the fourth embodiment of the present disclosure. The impeller 10 according to the fourth embodiment differs from the first to third embodiments in the configuration of the blades 20 at the inner circumferential end 24. In the fourth embodiment, parts common to the first to third embodiments are assigned the same reference numerals and description thereof will be omitted, and the following description will focus on the differences from the first to third embodiments.

[0058] 13 to 15, the blade 20 has a configuration in which the stagger angle 31 is 90 degrees at the inner circumferential end 24, decreases from the inner circumferential end 24 to the first chord cross section 41, and then increases from the first chord cross section 41 to the second chord cross section 42. Note that in Figs. 13 to 15, a general blade 20 is shown to simplify the description of the stagger angle 31 of the blade 20, and that this differs from the blade 20 that constitutes the impeller 10 of the present disclosure.

[0059] By making the stagger angle 31 90 degrees at the inner circumferential end 24 of the blade 20, the height of the boss 12 to which the blade 20 is connected along the rotation axis 11 can be reduced. In other words, the inner circumferential end 24 of the blade 20 can be connected to the boss 12 as long as the distance from the upper surface to the lower surface, which is the height of the boss 12, is at least the distance from the pressure surface 25 to the suction surface 26, which is the thickness of the blade 20. In other words, since the height of the boss 12 along the rotation axis 11 depends on the inner circumferential end 24 of the blade 20, by making the stagger angle 31 of the blade 20 90 degrees at the inner circumferential end 24, the chord 30 of the blade 20 in the first chord cross section 41 can be increased.

[0060] Furthermore, the blade 20 and the boss portion 12 are smoothly connected at the upper and lower surfaces of the boss portion 12. The boss portion 12 has a shape in which the upper and lower surfaces are at approximately the same height as the pressure surface 25 and the suction surface 26 at the inner circumferential end portion 24 of the blade 20. In other words, if the distance between the pressure surface 25 and the suction surface 26 of the blade 20 is defined as the thickness of the blade 20, the height of the boss portion 12 along the rotation shaft 11 can be set to approximately the thickness of the blade 20. Therefore, the height of the boss portion 12 is suppressed, and when the blades 20 are stacked and transported, the number of blades 20 that can be loaded can be increased, which is expected to improve productivity.

[0061] For example, when the stagger angle 31 of the blades 20 is reduced to increase the work of the blades 20 near the rotating shaft 11, the blade chord length needs to be increased, but the blades 20 with the reduced stagger angle 31 and increased blade chord length increase the height of the boss portion 12 in the direction of the rotating shaft 11. As a result, the volume of the entire impeller 10 increases.

[0062] In contrast to this, in the impeller 10 of the fourth embodiment, the stagger angle 31 of the blades 20 is 90 degrees at the inner circumferential end 24, so that the height of the boss portion 12 can be reduced to the minimum. As a result, the work on the inner circumferential end 24 side of the blades 20 is increased without expanding the boss portion 12 in the direction of the rotation shaft 11, making the blades 20 more efficient, and the overall volume of the impeller 10 is reduced, enabling resource conservation by reducing the amount of material used in the impeller 10.

[0063] Fig. 16 is a projection view of impellers 10 according to the fourth embodiment of the present disclosure stacked in the direction of the rotation shaft 11 on a plane perpendicular to the rotation shaft 11. As shown in Fig. 16, a plurality of impellers 10 are shipped stacked in the direction of the rotation shaft 11. Because the height of the boss portion 12 of the impeller 10 can be set to approximately the distance from the pressure surface 25 to the suction surface 26 of the blades 20, the number of impellers 10 stacked in the direction of the rotation shaft 11 can be increased to the maximum. In other words, the number of impellers 10 that can be transported at one time can be increased.

[0064] For example, if the height of the boss portion 12 in the direction of the rotation shaft 11 increases, when multiple impellers 10 are stacked in the direction of the rotation shaft 11 and transported, the number of impellers 10 that can be stacked in the direction of the rotation shaft 11 is limited. With the impeller 10 according to embodiment 4, the height of the boss portion 12 in the direction of the rotation shaft 11 can be reduced, thereby increasing the number of impellers 10 that can be stacked in the direction of the rotation shaft 11 of the impellers 10, and reducing the transportation cost of the impellers 10. As a result, the efficiency of the impeller 10 as a whole can be increased without increasing the height of the boss portion 12 in the direction of the rotation shaft 11.

[0065] In the impeller 10 according to the fourth embodiment described above, the stagger angle 31 of the blades 20 is 90 degrees at the inner circumferential end 24. This improves the work on the inner circumferential side of the blades 20, and also allows the inner circumferential end 24 of the blade 20 to be connected to the boss 12 as long as the distance from the upper surface to the lower surface, which is the height of the boss 12, is at least the distance from the pressure surface 25 to the suction surface 26, which is the thickness of the blade 20. This reduces the height of the boss 12, and increases the number of blades 20 that can be loaded when the blades 20 are stacked for transportation, which is expected to improve productivity.

[0066] Furthermore, because the blades 20 are smoothly connected to the boss portion 12, the height of the boss portion 12 in the direction of the rotation shaft 11 can be reduced to the minimum, thereby suppressing the overall volume of the impeller 10 and enabling resource conservation by reducing the amount of material used for the impeller 10. Furthermore, because the height of the boss portion 12 in the direction of the rotation shaft 11 can be set to approximately the distance from the pressure surface 25 to the suction surface 26 of the blade 20, the number of impellers 10 that can be stacked in the direction of the rotation shaft 11 can be increased to the maximum, which in turn increases the number of blades 20 that can be transported at one time. This makes it possible to reduce the cost of transporting the blades 20.

[0067] Fifth Embodiment. Figure 17 is a cross-sectional view showing a blower 100 according to a fifth embodiment of the present disclosure. The fifth embodiment relates to a blower 100, and differs from the first to fourth embodiments relating to the impeller 10. In the fifth embodiment, parts common to the first to fourth embodiments are given the same reference numerals and description thereof will be omitted, and the following description will focus on the differences from the first to fourth embodiments. Figure 17 is a cross-sectional view of an arbitrary plane that is parallel to and passes through the rotation shaft 11.

[0068] As shown in Fig. 17, the blower 100 includes a casing 80 having a bell mouth 81, and an impeller 10 arranged on the inner circumferential side of the bell mouth 81. The impeller 10 is, for example, the impeller 10 according to any one of the first to fourth embodiments. However, in Fig. 17, the impeller 10 is shown in the same manner as the trajectory of a typical blade 20 when rotated.

[0069] The casing 80 has a shape in which, for example, the distance from the rotary shaft 11 increases with increasing distance from the casing 80 on both the suction side 80a and the blowing side 80b from the substantially cylindrical bell mouth 81. The configuration of the casing 80 is not particularly limited, and may have any shape as long as, for example, the distance from the rotary shaft 11 does not decrease with increasing distance from the casing 80. In other words, the entire casing 80 may be cylindrical.

[0070] In Figure 17, the upper and lower impellers 10 drawn with dotted lines indicate the limits of the range in which the effect of the impeller 10 can be obtained when the impeller 10 is moved downward toward the suction side 80a and upward toward the blow-out side 80b. In Figure 17, when the height of the casing 80 is defined as Hb, the imaginary plane S is a plane that is spaced from the casing 80 toward the rotation axis 11 by εHb on the suction side 80a and the blow-out side 80b, and extends in a direction perpendicular to the rotation axis 11. As long as the impeller 10 is within the imaginary plane S, that is, even when spaced from the casing 80 toward the rotation axis 11, the effect of the impeller 10 can be obtained as long as it is within the range of εHb on the suction side 80a and the blow-out side 80b. In this case, ε may be 0.5.

[0071] As described above, according to the configuration of the fifth embodiment, it is possible to obtain a blower 100 that enables high efficiency of the impeller 10 and improvement in productivity.

[0072] In the blower 100 according to the fifth embodiment described above, the impeller 10 is surrounded by an imaginary plane S that is axially spaced apart by εHb from the suction side 80a and the blowout side 80b of the casing 80. This makes it possible to obtain a blower 100 with improved productivity without impairing the effect of the impeller 10, namely, the effect of increasing the efficiency of the impeller 10 as a whole while suppressing the increase in the size of the boss portion 12.

[0073] Sixth Embodiment Figure 18 is a perspective view of an air conditioner 200 according to a sixth embodiment of the present disclosure. The sixth embodiment relates to an air conditioner 200, and differs from the first to fourth embodiments relating to the impeller 10 or the fifth embodiment relating to the blower 100. In the sixth embodiment, parts common to the first to fifth embodiments are given the same reference numerals and description thereof will be omitted, and the following description will focus on the differences from the first to fifth embodiments.

[0074] The air conditioner 200 is, for example, an outdoor unit of a multi-air conditioner for a building. As shown in Fig. 18, the air conditioner 200 has a blower 100 equipped with an impeller 10 according to any one of embodiments 1 to 4. The air conditioner 200 also has a housing 203.

[0075] An air outlet 202 is formed in the top of the housing 203 for discharging outdoor air outside the air conditioner 200 of the housing 203. An air inlet 201 for drawing outdoor air is formed in each side surface of the housing 203. The air inlet 201 does not have to be provided on all four sides of the housing 203. The air inlet 201 may be formed in a part of the side surface of the housing 203, or may be formed on the entire side surface.

[0076] 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 on the air intake side of the air outlet 202 and downstream of the heat exchanger 204 in the air flow. The heat exchanger 204 exchanges heat between air drawn into the housing 203 from the outside and the refrigerant flowing inside the heat exchanger 204, and, for example, absorbs heat from the air during heating and releases heat to the air during cooling.

[0077] When impeller 10 of blower 100 rotates, air outside housing 203 is drawn into housing 203 through intake port 201. The air drawn into housing 203 is supplied to heat exchanger 204, and is blown out of housing 203 through outlet 202, either in a state where heat is absorbed as the air passes through heat exchanger 204, causing the air to cool down, or in a state where the air is subject to heat exhaust, causing the air to cool down.

[0078] As described above, blower 100 enables high efficiency and improved productivity of impeller 10. Air conditioner 200 according to embodiment 6 includes impeller 10 and heat exchanger 204, and air supplied by impeller 10 exchanges heat with refrigerant circulating therein in heat exchanger 204. Therefore, air conditioner 200 according to embodiment 6 can improve power efficiency and productivity.

[0079] The air conditioner 200 according to the sixth embodiment described above exchanges heat between the air supplied by the impeller 10 and the refrigerant circulating inside the heat exchanger 204. The impeller 10 is highly efficient due to the shape in which the stagger angle 31 of the blades 20 changes from the inner circumferential end 24 to the second chord direction cross section 42, so that the air conditioner 200 has good power efficiency and improved productivity.

[0080] It should be noted that the first to sixth embodiments can be combined as appropriate.

[0081] Various aspects of the present disclosure are summarized below as appendices.

[0082] an impeller comprising: a boss portion provided on a rotation shaft; and blades provided on an outer periphery of the boss portion, wherein the blades have: a leading edge portion that is a front edge portion in a rotation direction; a trailing edge portion that is a rear edge portion in the rotation direction; an outer peripheral end portion that is an edge portion on an outer periphery side; and an inner peripheral end portion that is an edge portion on an inner periphery side; a cross section of the blade cut by a cylinder centered on the rotation shaft is defined as a chord direction cross section; a line segment connecting the leading edge portion and the trailing edge portion in the chord direction cross section is defined as a blade chord, and an angle formed by the rotation shaft and the blade chord is defined as a stagger angle; the stagger angle is defined as an angle at which the trailing edge portion of the blade is inclined toward the suction surface of the blade; the chord direction cross sections include a first chord direction cross section and a second chord direction cross section that is outer than the first chord direction cross section; and the stagger angle of the blade decreases from the inner periphery end portion to the first chord direction cross section and increases from the first chord direction cross section to the second chord direction cross section. (Note 2) The distance from the rotation axis to the inner peripheral end is r ｂ The distance from the rotation axis to the outer circumferential end is r ｔ The distance from the rotation axis to the first chord direction cross section is r ｄ a constant is α, and the distance from the rotation axis to the second chord direction cross section is αr ｄ When this is the case, r ｂ <r ｄ ≦0.5r ｔ and α=1.01. (Supplementary Note 3) The impeller according to Supplementary Note 1 or 2, wherein a drainage point is provided at the leading edge of the blade at a position closest to the suction side within the range of the second chord direction cross section from the inner circumferential end. (Supplementary Note 4) The impeller according to Supplementary Note 1, wherein a distance from the rotation axis is r ｓ When the cross section in the cord direction where ｂ <r ｓ <r ｄThe impeller according to Supplementary Note 2, wherein adjacent blades are connected from the inner circumferential end to the third chord direction cross section. (Supplementary Note 5) The impeller according to any one of Supplementary Notes 1 to 4, wherein the stagger angle of the blades is 90 degrees at the inner circumferential end. (Supplementary Note 6) The impeller according to any one of Supplementary Notes 1 to 5, wherein the boss portion and the blade are smoothly connected. (Supplementary Note 7) A blower comprising: the impeller according to any one of Supplementary Notes 1 to 6; and a casing having a bell mouth surrounding the impeller from the outside in the radial direction, wherein, when the height of the casing is Hb and ε is 0.5, the impeller is surrounded within imaginary planes that are axially spaced apart from the suction side and the blowing side of the casing by εHb. (Supplementary Note 8) An air conditioner comprising: the impeller according to any one of Supplementary Notes 1 to 6; and a heat exchanger that exchanges heat between air supplied by the impeller and a refrigerant circulating therethrough.

[0083] 10 impeller, 11 rotating shaft, 12 boss portion, 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 end portion, 24a inner peripheral front end portion, 24b inner peripheral rear end portion, 25 pressure surface, 26 suction surface, 30 blade chord, 31 angle, 41 first chord direction cross section, 42 second chord direction cross section, 43 third chord direction cross section, 50 drainage location, 51 drainage flow path, 80 casing, 80a suction side, 80b blowing side, 81 bell mouth, 100 blower, 121 outer peripheral wall, 200 air conditioner, 201 suction port, 202 blowing port, 203 housing, 204 heat exchanger, 205 step.

Claims

1. An impeller comprising: a boss portion provided on a rotation shaft; and blades provided on the outer periphery of the boss portion, wherein the blades have a leading edge portion that is the front edge in the direction of rotation, a trailing edge portion that is the rear edge in the direction of rotation, an outer peripheral end portion that is the edge on the outer periphery, and an inner peripheral end portion that is the edge on the inner periphery, wherein a cross section of the blade cut by a cylinder centered on the rotation shaft is defined as a chord direction cross section, wherein a line segment connecting the leading edge and the trailing edge portion in the chord direction cross section is defined as a blade chord, and an angle formed by the rotation shaft and the blade chord is defined as a stagger angle, and wherein an angle at which the trailing edge of the blade is inclined toward the suction surface of the blade is defined as a positive stagger angle, and the chord direction cross sections include a first chord direction cross section and a second chord direction cross section that is outer than the first chord direction cross section, and wherein the stagger angle of the blade decreases from the inner periphery end portion to the first chord direction cross section and increases from the first chord direction cross section to the second chord direction cross section.

2. The distance from the rotation axis to the inner peripheral end is r ｂ The distance from the rotation axis to the outer circumferential end is r ｔ The distance from the rotation axis to the first chord direction cross section is r ｄ a constant is α, and the distance from the rotation axis to the second chord direction cross section is αr ｄ When this is the case, r ｂ <r ｄ ≦0.5r ｔ 2. The impeller according to claim 1, wherein α=1.

01.

3. An impeller as described in claim 1 or 2, wherein a drainage point is provided at the leading edge of the blade at a position closest to the suction side within the range of the second chord direction cross section from the inner circumferential end.

4. The distance from the rotation axis is r ｓ When the cross section in the cord direction where ｂ <r ｓ <r ｄ The impeller according to claim 2, wherein adjacent blades are connected from the inner circumferential end portion to the third chord direction cross section.

5. An impeller according to any one of claims 1 to 4, wherein the stagger angle of the blades is 90 degrees at the inner peripheral end.

6. An impeller according to any one of claims 1 to 5, wherein the boss portion and the blades are smoothly connected.

7. A blower comprising: an impeller according to any one of claims 1 to 6; and a casing having a bell mouth surrounding the impeller from the outside in the radial direction, wherein, when the height of the casing is Hb and ε is 0.5, the impeller is surrounded within imaginary planes that are axially spaced an amount εHb from the suction side and the blowing side of the casing.

8. An air conditioner comprising: an impeller according to any one of claims 1 to 6; and a heat exchanger that exchanges heat between air supplied by the impeller and a refrigerant circulating therein.

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