Multi-blade impeller and centrifugal blower

Abstract

The present invention relates to a multi-blade impeller and a centrifugal blower, wherein the multi-blade impeller comprises: a main plate which rotates around a rotation axis and is circular when viewed along the rotation axis; a plurality of blades (4) which are arranged at intervals along the outer periphery of the main plate and extend in the direction along the rotation axis; and an annular reinforcement ring (5) which is arranged at a position separated from the main plate in the direction along the rotation axis and surrounds the plurality of blades (4). A protrusion (6) which protrudes in a direction different from the outlet direction of the blade (4) and in a radially outer direction of the main plate is provided on an outer edge portion (4a) of the blade (4), and the plurality of blades (4) are connected to the reinforcement ring (5) via the protrusion (6).

Description

Technical Field

[0001] The present invention relates to a multi-blade impeller having a plurality of blades and a centrifugal blower. Background Art

[0002] The multi-blade impeller is configured as follows: the impeller, which has a plurality of blades arranged in a ring shape, is rotated, and the air sucked from the inner periphery of the impeller is blown out in a centrifugal direction from between the blades. The rotational motion causes centrifugal force to act on the blades of the multi-blade impeller, so an annular reinforcement ring that fixes the plurality of blades is usually connected to the outer edge of the blade. By providing the reinforcement ring, deformation of the blade can be suppressed.

[0003] In addition, as disclosed in Patent Document 1, in order to obtain a larger air volume through the rotation of a multi-blade impeller, a multi-blade impeller is used in which the shape of the blades is set to be forward relative to the rotation direction and the outlet angle of the blades is greater than 90°. For example, there is a multi-blade impeller in which the outlet angle of the blades is set to 150 to 170°.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 6-74195

[0005] In the blade with an outlet angle greater than 90°, the connection angle with the reinforcement ring becomes an acute angle, resulting in a portion where stress is easily concentrated. Therefore, there is a problem that deformation of the blade cannot be fully suppressed simply by connecting the blade to the reinforcement ring. Summary of the invention

[0006] The present invention has been made in view of the above-mentioned situation, and an object of the present invention is to provide a multi-blade impeller capable of suppressing deformation of blades.

[0007] In order to solve the above-mentioned problems and achieve the purpose, the present invention comprises: a main plate that rotates around a rotation axis and is circular when viewed along the rotation axis; a plurality of blades that are arranged at intervals along the outer periphery of the main plate and extend in the direction along the rotation axis; and an annular reinforcement ring that is disposed at a position separated from the main plate in the direction along the rotation axis and surrounds the plurality of blades. A protrusion that protrudes in a direction different from the outlet direction of the blade and toward the radially outer side of the main plate is disposed on the outer edge of the blade, and the plurality of blades are connected to the reinforcement ring via the protrusion.

[0008] According to the present invention, there is an effect that a multi-blade impeller capable of suppressing deformation of blades can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a perspective view of the centrifugal blower according to Embodiment 1.

[0010] Figure 2This is a perspective view of the multi-blade impeller according to the first embodiment.

[0011] Figure 3 This is a plan view of the multi-blade impeller according to the first embodiment.

[0012] Figure 4 Yes Figure 3 The enlarged partial view of part K shown.

[0013] Figure 5 It is along Figure 4 A cross-sectional view taken along line VV is shown.

[0014] Figure 6 It is a top view of a multi-blade impeller of a comparative example.

[0015] Figure 7 Yes Figure 6 The enlarged partial view of part L shown.

[0016] Figure 8 This is a partially enlarged view of the multi-blade impeller of Modification Example 1.

[0017] Fig. 9 This is a partially enlarged view of the multi-blade impeller of Modification Example 2.

[0018] Fig.10 This is a partially enlarged view of the multi-blade impeller of Modification 3.

[0019] Fig.11 It is along Fig.10 A cross-sectional view taken along line XI-XI is shown.

[0020] Fig.12 is a cross-sectional view of the multi-blade impeller of Modification 4, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0021] Fig.13 is a cross-sectional view of the multi-blade impeller of Modification 5, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0022] Fig.14 This is a cross-sectional view showing an example of the position of the reinforcement ring provided in the multi-blade impeller according to the first embodiment.

[0023] Fig.15 is a cross-sectional view of the multi-blade impeller of Modification 6, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0024] Fig.16 This is a perspective view of a multi-blade impeller according to Modification 6.

[0025] Fig.17 is a cross-sectional view of the multi-blade impeller of Modification 7, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0026] Fig.18 is a cross-sectional view of the multi-blade impeller of Modification 8, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0027] Fig.19 is a cross-sectional view of the multi-blade impeller of modification example 9, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0028] Fig. 20 This is a diagram comparing the maximum stress values ​​applied to the multi-blade impeller according to the first embodiment and the multi-blade impeller according to the comparative example. DETAILED DESCRIPTION

[0029] Hereinafter, the multi-blade impeller and the centrifugal fan according to the embodiment will be described in detail with reference to the drawings.

[0030] Implementation method 1.

[0031] Figure 1 1 is a perspective view of a centrifugal blower according to Embodiment 1. The centrifugal blower 7 includes a vortex casing 8, a multi-blade impeller 1, and a drive motor 2. The vortex casing 8 accommodates the multi-blade impeller 1 inside. The vortex casing 8 is provided with an inlet 10 for taking in air into the interior and an outlet 9 for blowing out air from the interior. The drive motor 2 rotates the multi-blade impeller 1 in the vortex casing 8. In the centrifugal blower 7, the air sucked in from the inlet 10 is blown out from the outlet 9 by the rotation of the multi-blade impeller 1.

[0032] Figure 2 This is a perspective view of the multi-blade impeller according to the first embodiment. Figure 3 1 is a top view of a multi-blade impeller according to Embodiment 1. The multi-blade impeller 1 is rotated about a rotation axis 11 by driving a motor 2. The multi-blade impeller 1 includes a main plate 3 that is circular when viewed along the rotation axis 11. The multi-blade impeller 1 includes a plurality of blades 4 that are arranged at intervals along the outer periphery of the main plate 3 and extend in a direction along the rotation axis 11. The multi-blade impeller 1 includes an annular reinforcement ring 5 that surrounds the plurality of blades 4 and is disposed at a position separated from the main plate 3 in the direction along the rotation axis 11.

[0033] Figure 4 Yes Figure 3 The enlarged partial view of part K shown. Figure 5 It is along Figure 4The outer edge 4a of the blade 4 is provided with a protrusion 6 protruding radially outward from the main plate 3 in a direction different from the outlet direction A determined by the outlet angle α of the blade 4. The plurality of blades 4 are connected to the inner peripheral surface 5a of the reinforcement ring 5 via the protrusion 6.

[0034] The multi-blade impeller 1 is rotated by the driving motor 2, so that a centrifugal force F acts on the outer periphery of the multi-blade impeller 1. In addition, by providing a protrusion 6 in a direction opposite to the centrifugal force F, a centripetal force G acts on the blade 4 through the protrusion 6. The blade 4 is connected to the reinforcement ring 5 via the protrusion 6, so that the connection angle between the blade 4 and the reinforcement ring 5 is not an acute angle, and thus the stress generated at the connection portion between the blade 4 and the protrusion 6 is difficult to concentrate. Therefore, deformation of the blade 4 can be suppressed. Since the stress generated at the connection portion between the blade 4 and the protrusion 6 is difficult to concentrate, the blade 4 can be made thinner, the blade 4 can be formed with a low-strength and cheap material, and the manufacturing cost of the multi-blade impeller 1 can be suppressed.

[0035] In addition, if Figure 5 As shown, a protrusion 6 protruding from the outer edge 4a of the blade 4 is provided between the outer edge 4a of the blade 4 and the inner peripheral surface 5a of the reinforcement ring 5, so that when the reinforcement ring 5 is projected along the rotation axis 11, the main board 3 is provided at a position avoiding the projection. Thus, when the multi-blade impeller 1 is manufactured by injection molding, the mold can be pulled out in the direction of the rotation axis 11. Since the mold can be pulled out in the direction of the rotation axis 11, it is not necessary to change the shape of the main board 3 in consideration of the pulling out of the mold. Therefore, the shape of the mold can be simplified and the cost spent on the design of the mold can be suppressed, and the manufacturing cost of the multi-blade impeller 1 can be suppressed.

[0036] Figure 6 It is a top view of a multi-blade impeller of a comparative example. Figure 7 Yes Figure 6 The L portion is enlarged in the partial enlarged view shown. The outer edge 4a of the blade 4 of the multi-blade impeller 101 of the comparative example is directly connected to the reinforcement ring 105. In the multi-blade impeller 101 of the comparative example, since the blade 4 and the reinforcement ring 5 are connected at an acute angle, stress is easily concentrated on the connection parts P and Q of the blade 4 and the reinforcement ring 5 due to the centrifugal force F. Therefore, there is a case where the deformation of the blade 4 cannot be fully suppressed. In contrast, in the multi-blade impeller 1 of the present embodiment 1, by connecting the blade 4 and the reinforcement ring 5 via the protrusion 6, stress is not easily concentrated, and deformation of the multi-blade impeller 1 can be suppressed.

[0037] In addition, in the multi-blade impeller 101 of the comparative example, since the reinforcement ring 105 is directly connected to the outer edge portion 4a of the blade 4, the projection of the reinforcement ring 105 along the rotation axis 11 overlaps with the main plate 3. Therefore, when the multi-blade impeller 1 is manufactured by injection molding, it is necessary to change the shape of the main plate 3 in order to extract the mold in the direction along the rotation axis 11, and the manufacturing cost increases. In contrast, in the multi-blade impeller 1 of the present embodiment 1, since the mold can be extracted in the direction along the rotation axis 11, it is not necessary to change the shape of the main plate 3, and the manufacturing cost can be suppressed.

[0038] Figure 8 This is a partial enlarged view of the multi-blade impeller of Modification Example 1. Figure 4 In the example shown, the multi-blade impeller 1 is in the shape of blades facing forward with respect to the rotation direction, so the curvature radius at the negative pressure surface 4b of the blade 4 and the positive pressure surface 4c of the blade 4 are different according to the thickness of the blade 4, and the angle of connection to the protrusion 6 is also different on the negative pressure surface 4b side of the blade 4 and the positive pressure surface 4c side of the blade 4. Therefore, the stress generated at the connection portion between the blade 4 and the protrusion 6 is different in magnitude on the negative pressure surface 4b side of the blade 4 and the positive pressure surface 4c side of the blade 4.

[0039] Therefore, in the multi-blade impeller 1 of the modification example 1, as Figure 8 As shown, regarding the protrusion 6 provided at the outer edge 4a of the blade 4, the cross-sectional area, shape and connection angle of the protrusion 6 are changed toward the radially outer side of the main plate 3. As a result, the stress generated on the negative pressure surface 4b of the blade 4 and the stress generated on the positive pressure surface 4c of the blade 4 can be reduced, respectively, so that the strength of the multi-blade impeller 1 can be expected to be further improved.

[0040] The larger the connection area of ​​the protrusion 6 connected to the outer edge 4a of the blade 4, the lower the stress generated at the connection portion between the blade 4 and the protrusion 6. On the other hand, the more the weight of the protrusion 6 increases, the more the centrifugal force acting on the blade 4 increases, and thus the stress generated at the connection portion between the blade 4 and the protrusion 6 increases. Therefore, in the multi-blade impeller 1 of Modification 1, the width along the circumferential direction of the main board 3 is reduced toward the radial outer side of the main board 3, thereby reducing the cross-sectional area of ​​the protrusion 6. As a result, the connection area between the protrusion 6 and the blade 4 can be ensured and the weight of the protrusion 6 can be suppressed to connect the protrusion 6 to the blade 4, so that it can be expected that the strength of the impeller can be more effectively improved.

[0041] Fig. 9: is a partial enlarged view of the multi-blade impeller of modification example 2. As described above, since the radius of curvature of the positive pressure surface 4c of the blade 4 is smaller than the radius of curvature of the negative pressure surface 4b of the blade 4, the angle of connection with the protrusion 6 becomes an acute angle. Therefore, the stress generated at the connection portion between the positive pressure surface 4c of the blade 4 and the protrusion 6 is higher than the stress generated at the connection portion between the negative pressure surface 4b of the blade 4 and the protrusion 6. Therefore, in the multi-blade impeller 1 of modification example 2, when viewed along the rotation axis 11, the side surface 6a of the protrusion 6 connected to the positive pressure surface 4c of the blade 4 overlaps with the radial line M from the rotation axis 11. In addition, the side surface 6a of the protrusion 6 is a surface that becomes the front side of the rotation direction of the multi-blade impeller 1. Since the centripetal force G of the protrusion 6 becomes the largest toward the rotation axis 11, by forming the side surface 6a in a manner overlapping with the radial line M from the rotation axis 11, the stress generated at the connection portion between the positive pressure surface 4c of the blade 4 and the protrusion 6 can be further reduced.

[0042] Fig.10 This is a partially enlarged view of the multi-blade impeller of Modification 3. Fig.11 It is along Fig.10 A cross-sectional view taken along line XI-XI is shown. Fig.12 is a cross-sectional view of the multi-blade impeller of Modification 4, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI. Fig.13 is a cross-sectional view of the multi-blade impeller of Modification 5, which is equivalent to the Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0043] In the multi-blade impeller 1 of Modifications 3 to 5, the reinforcement ring 5 is provided with a plurality of inner circumferential surfaces 5a1 and 5a2 directed radially inward, and at least one of the inner circumferential surfaces 5a1 and 5a2 is inclined with respect to the rotation axis 11. Thus, the width of the reinforcement ring 5 from the radially inner end toward the radially inner side and in the direction along the rotation axis 11 is increased, and the cross-sectional area of ​​the cross section cut along the surface along the circumferential direction is also increased.

[0044] Here, since bending stress acts on the connection parts between the blades 4 and the protrusions 6 of the multi-blade impeller 1 and the connection parts between the reinforcement ring 5 and the protrusions 6, the stress on the surface becomes larger than that inside the material. In the multi-blade impeller 1 of modification examples 3 to 5, by providing a plurality of inner peripheral surfaces 5a1, 5a2 on the reinforcement ring 5, the cross-sectional shape in the direction of the rotation axis of the protrusion 6 connected to the reinforcement ring 5 and the connection angle can be adjusted according to the plurality of inner peripheral surfaces 5a1, 5a2. Therefore, compared with the case where the inner peripheral surface of the reinforcement ring 5 is formed by only one surface, the connection area of ​​the protrusion 6 connected to the outer edge portion 4a of the blade 4 can be maintained according to the generated stress, and the weight of the protrusion 6 can be further suppressed. In addition, in Fig.10In the multi-blade impeller 1 of the third modification shown, the protrusion 6 is smaller in the region where the stress inside the material is small. In addition, the inner peripheral surface may be formed of three or more surfaces.

[0045] Fig.14 1 is a cross-sectional view showing an example of the position of the reinforcement ring provided in the multi-blade impeller of Embodiment 1. Fig.14 As shown, when the multi-blade impeller 1 rotates, air flows from the radial inside to the radial outside in the reinforcement ring 5. In the multi-blade impeller 1 of Modifications 3 to 5, since the width of the reinforcement ring 5 is expanded from the radial inside end toward the radial inside, along the direction of the rotating shaft 11, the air flowing from the radial inside to the radial outside can pass smoothly. Thus, it is possible to achieve a reduction in noise and an improvement in air supply performance.

[0046] In addition, if Fig.14 As shown in FIG. 1 , since inertial force is generated in the air flowing in the multi-blade impeller 1, the velocity distribution becomes biased toward the main plate 3 side. Fig.14 As shown, when the reinforcement ring 5 is set in the middle of the outer edge portion 4a of the blade 4 of the multi-blade impeller 1 along the direction of the rotating axis 11, a plurality of inner circumferential surfaces 5a1, 5a2 are provided on the reinforcement ring 5 and the width along the direction of the rotating axis 11 is expanded from the radial inner end toward the radial inner side, thereby increasing the effect of smoothing the flow of air.

[0047] Furthermore, the inner peripheral surface 5 a may be provided with projections and depressions or a curved surface so that the air blown out from between the blades 4 of the multi-blade impeller 1 can easily flow around the reinforcing ring 5 .

[0048] Fig.15 is a cross-sectional view of the multi-blade impeller of Modification 6, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI. Fig.16 It is a stereoscopic view of a multi-blade impeller of modification example 6. In the multi-blade impeller 1 of modification example 6, a portion of the reinforcement ring 5 is directly connected to the outer edge portion 4a of the blade 4. Specifically, the width along the radial direction is different between the surface of the reinforcement ring 5 facing the main board 3 side, that is, the lower surface 5b, and the surface of the reinforcement ring 5 facing the side opposite to the main board 3 side, that is, the upper surface 5c. In the multi-blade impeller 1 of modification example 6, the width along the radial direction of the lower surface 5b is wider than the width along the radial direction of the upper surface 5c. In addition, the lower surface 5b protrudes radially inward more than the upper surface 5c, so that the area of ​​the inner circumferential surface of the reinforcement ring 5 on the side close to the main board 3 is directly connected to the outer edge portion 4a of the blade 4. As a result, although the connection area between the protrusion 6 and the blade 4 is reduced, and the effect of improving the strength of the impeller is reduced, it is easy to form the reinforcement ring 5 in one piece, so that the manufacturing cost can be suppressed.

[0049] Fig.17is a cross-sectional view of the multi-blade impeller of Modification 7, which is equivalent to the cross-sectional view along Fig.10 XI-XI line cross-sectional view shown in FIG. In the multi-blade impeller 1 of Modification 7, the width of the upper surface 5c along the radial direction is wider than the width of the lower surface 5b along the radial direction, which is opposite to the example shown in Modification 6. In addition, the upper surface 5c protrudes radially inwardly more than the lower surface 5b, so that the area of ​​the inner peripheral surface of the reinforcement ring 5 on the side close to the main plate 3 is directly connected to the outer edge 4a of the blade 4.

[0050] Fig.18 is a cross-sectional view of the multi-blade impeller of Modification 8, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI. Fig.19 is a cross-sectional view of the multi-blade impeller of modification example 9, which is equivalent to the cross-sectional view along Fig.10 The figure is a cross-sectional view taken along line XI-XI.

[0051] In the multi-blade impeller 1 of modification examples 8 and 9, the protrusion 6 is connected to the inner peripheral surface 5a of the reinforcement ring 5, and the surface of the reinforcement ring 5 facing the main board 3, that is, the lower surface 5b side, is also extended or connected, thereby improving the strength of the multi-blade impeller 1.

[0052] Fig. 20 This is a graph comparing the maximum stress values ​​applied to the multi-blade impeller of Embodiment 1 and the multi-blade impeller of the comparative example. The maximum stress value is calculated based on structural analysis. Fig. 20 As shown, relative to the multi-blade impeller 101 of the comparative example, Fig. 9 The maximum stress value of the multi-blade impeller 1 of the second modification example shown is reduced by about 7%. Fig.11 The maximum stress value of the multi-blade impeller 1 of the modified example 3 shown is reduced by about 14%.

[0053] The multi-blade impeller illustrated in the first embodiment can be applied not only to a single-suction centrifugal blower but also to a double-suction centrifugal blower. In addition, it can be applied not only to a blower for air conditioning ventilation but also to other equipment. In addition, the shape of the protrusion 6 and the shape of the reinforcement ring 5 shown in each modification can also be combined.

[0054] The structure shown in the above embodiment is just one example, and it is possible to combine with other known technologies, and it is possible to combine the modified examples with each other. It is also possible to omit or change part of the structure without departing from the scope of the invention.

[0055] Description of the attached figure

[0056] 1. 101…multi-blade impeller; 2…driving motor; 3…main board; 4…blades; 4a…outer edge; 5. 105…reinforcement ring; 5a, 5a1, 5a2…inner circumference; 5b…lower surface; 6…protrusion; 7…centrifugal blower; 8…vortex casing; 9…blowing outlet; 10…intake port; 11…rotating shaft.

Claims

1. A multi-blade impeller, characterized in that: have: A main board, which rotates around a rotation axis and has a circular shape when viewed along the rotation axis; a plurality of blades arranged at intervals from each other along the outer periphery of the main plate and extending in a direction along the rotation axis; as well as an annular reinforcement ring, which is arranged at a position separated from the main plate in the direction along the rotation axis and surrounds the plurality of blades; A protrusion is provided on the outer edge portion of the blade which becomes the outer peripheral edge side. The protrusion protrudes in a direction different from the outlet direction of the blade and toward the radial outer side of the main plate. The cross-sectional area of ​​the protrusion cut along a surface along the circumferential direction of the main plate decreases toward the outer side in the radial direction. The plurality of blades are connected to the reinforcement ring via the protrusions.

2. The multi-blade impeller according to claim 1, characterized in that: A surface of the protruding portion that is on the front side in the rotation direction of the main plate overlaps with radiation from the rotation axis when viewed along the rotation axis.

3. The multi-blade impeller according to claim 1 or 2, characterized in that: The cross-sectional area of ​​the reinforcement ring, which is cut along a surface along the circumferential direction of the main plate, increases toward the outer side in the radial direction.

4. The multi-blade impeller according to any one of claims 1 to 3, characterized in that: In the reinforcement ring, a portion of the inner peripheral surface is connected to the outer peripheral edge of the blade.

5. A centrifugal blower, characterized in that: have: The multi-blade impeller according to any one of claims 1 to 4; and The scroll housing houses the multi-blade impeller.

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