Centrifugal Blower

Abstract

To provide a centrifugal blower 10 which enables integral molding of a shroud 62, an impeller cup 66, and multiple blades 60 with a slide mold while suppressing generation of noise.SOLUTION: In a centrifugal blower 10, a cover area 62b is formed into an arc shape protruding to the other side in a fan axis direction DRa on a sectional view in which a shroud 62 is cut on a plane including a fan axis Sa. The shroud 62 is formed so as to proceed to one side in the fan axis direction DRa in a direction from an outer end 62d as seen in a fan radial direction DRr of the cover area 62b to an inner end 62e as seen in the fan radial direction DRr. One side as seen in the fan axis direction DRa of an impeller cup 66 is provided with an inclined surface 67 which is formed so as to proceed to the one side in the fan axis direction DRa in a direction from the outer side to the inner side in the fan radial direction DRr.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a centrifugal blower. [Background technology]

[0002] Conventionally, some centrifugal blowers include a plurality of blades arranged in a circumferential direction centered on an axis, a shroud arranged on one side of the plurality of blades in the fan axial direction, and a main plate arranged on the other side of the plurality of blades in the fan axial direction (see, for example, Patent Document 1).

[0003] An intake port is provided on the radially inner side of the shroud about the axis. The back surface of the shroud on the other side in the fan axial direction is formed in a curved shape that approaches one side in the fan axial direction as it progresses from the radially outer side to the radially inner side.

[0004] An impeller cup is provided on the other side of the main plate in the fan axial direction, supporting the rotor of the electric motor from its radially outer side. The radial dimension of the impeller cup about the axis is larger than the radial dimension of the intake port about the axis.

[0005] When the rotor of the electric motor rotates about its axis, the impeller cup rotates about its axis. At this time, the main plate, the blades, and the shroud rotate together with the impeller cup. At this time, airflow flowing into the intake port from one side in the fan axial direction is blown outward in the radial direction through multiple air passages between two adjacent blades. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-203481 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventor, with reference to the above-mentioned Patent Document 1, investigated ways to suppress noise generation by smoothly circulating the air flow flowing into the intake port through multiple air flow paths between the shroud and the main plate.

[0008] According to the inventor's investigations, in a cross-sectional view of the shroud cut along a plane including the axis, the cover region of the shroud which overlaps with the impeller cup in the axial direction needs to be formed in an arc shape that convexly extends to the other side in the fan axial direction.

[0009] However, when the shroud, impeller cup, multiple blades, and main plate are integrally molded using a resin material or the like, if the multiple air flow passages between the impeller cup and the main plate and the shroud are molded using a slide mold, the shape of the shroud is limited.

[0010] For example, in order to enable the slide mold to slide radially inward relative to the shroud, impeller cup, multiple blades, and main plate, a shape with an inclination angle of 0 degrees or more between the shroud and the main plate is required.

[0011] However, depending on the shape of the main plate, it may not be possible to realize an inclination angle of 0 degrees or more. Therefore, when the shroud, impeller cup, multiple blades, and main plate are integrally molded using a slide mold, it may not be possible to form the cover area of ​​the shroud into the above-mentioned arc-shaped cross section.

[0012] Therefore, the present inventors have considered integrally molding the shroud, the plurality of blades, and the impeller cup (i.e., the cylindrical portion) other than the main plate using a slide mold.

[0013] In view of the above, an object of the present invention is to provide a centrifugal blower in which the shroud, the plurality of blades, and the tubular portion, excluding the main plate, can be integrally molded using a slide mold while suppressing the generation of noise. [Means for solving the problem]

[0014] In order to achieve the above object, the present invention provides a centrifugal blower, comprising: A plurality of blades (60) arranged in a circumferential direction (Edr) around an axis (Sa); a shroud (62) that is formed so as to cover the plurality of blades from one side in the axial direction when the direction in which the axis extends is defined as an axial direction (DRa), is provided in a ring shape centered on the axis, and forms an intake port (62a) that opens in the axial direction on the radially inner side centered on the axis; a main plate (64) that is formed so as to cover the plurality of blades from the other side in the axial direction, that is provided in a ring shape centered on the axis, and that further forms an opening (64a) that opens in the axial direction on the radially inner side; a tubular portion (66) that is disposed within the opening, is formed in a cylindrical shape centered on an axis, and is configured to be rotatable about the axis by a torque of the electric motor (14); The blades, the shroud, and the cylinder constitute an integrated structure (94), an air flow passage (68) is provided between the tubular portion and the main plate and between the shroud and between two adjacent blades of the plurality of blades; The cylindrical portion is connected to the main plate so as to be unable to move relative to the main plate, When the plurality of blades, the shroud, the tubular portion, and the main plate rotate in one circumferential direction (DRf) by the rotational force of the electric motor, air sucked into the intake port from one axial direction side is blown outward in the radial direction through the air flow path, A cover region (62b) is provided on the other side of the shroud in the axial direction so as to cover one side of the cylindrical portion in the axial direction, and the cover region is formed in an arc shape that is convex toward the other side in the axial direction in a cross-sectional view of the shroud cut along a plane including the axis, The shroud is formed to progress toward one side in the axial direction from a radially outer end (62d) of the cover region toward a radially inner end (621) of the shroud, An end face (67) is provided at one end of the cylindrical portion in the axial direction, When a line perpendicular to the axial direction and perpendicular to the radial direction is defined as a first virtual line (230), and a tangent line perpendicular to the first virtual line and tangent to the cover area is defined as a second virtual line (162b), the cover area and the end face are formed so that the end face of the tubular portion and the second virtual line are parallel, or the axial distance (ZL) between the end face and the second virtual line increases from the radial inside to the radial outside.

[0015] As a result, the cover region of the shroud is formed in an arc shape that is convex toward the other axial side in a cross-sectional view of the shroud cut along a plane including the axis. The shroud is formed to progress toward one axial side from the radial outer end (62d) of the cover region toward the radial inner end of the shroud. Therefore, the air drawn into the intake port can flow smoothly along the cover area, thereby suppressing the generation of noise that occurs when the air flows into the air flow path.

[0016] Furthermore, the cover area and the end face are formed so that the end face and the second imaginary line are parallel, or the axial distance between the end face and the second imaginary line increases from the radial inside to the radial outside. Therefore, when the shroud, the blades, and the cylindrical portion are integrally molded, when the area (220) between the cover area and the end face of the air flow passage is molded using a slide mold, the slide mold can be pulled outward in the radial direction from between the cover area and the inclined surface.

[0017] As a result, it is possible to provide a centrifugal blower in which the shroud, the plurality of blades, and the tubular portion can be integrally molded using a slide mold while suppressing the generation of noise.

[0018] Note that the reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and specific components described in the embodiments described below. [Brief description of the drawings]

[0019] [Figure 1] 1 is a cross-sectional view of a centrifugal blower according to a first embodiment, taken along a plane including a fan axis. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 in the first embodiment, in which the electric motor is omitted, and is a cross-sectional view for assisting in the description of the main plate, the plurality of blades, and the inclined surfaces of the impeller cup. [Diagram 3] 2 is a view of the shroud and the inside of the intake hole in FIG. 1 as viewed from one side in the fan axial direction in the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 in the first embodiment, and is a view for assisting in the description of the impeller cup and a plurality of blades. [Diagram 5] 2 is a partial enlarged view of a portion including a cover region of a shroud and an inclined surface of an impeller cup in FIG. 1 in the first embodiment. FIG. [Figure 6] FIG. 3 is a schematic diagram of the two blades in FIG. 2 in the first embodiment, showing an enlarged view of the periphery of the two blades on the inclined surface of the impeller cup, and is a partially enlarged view to assist in explaining the impeller inclination angle of the inclined surface. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6 in the first embodiment, and is a cross-sectional view for assisting in the explanation of the impeller inclination angle at a portion of the inclined surface of the impeller cup on the suction surface side of the blade. [Figure 8] FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 6 in the first embodiment, and is a cross-sectional view for assisting in the explanation of the impeller inclination angle at a portion of the inclined surface of the impeller cup on the pressure surface side of the blade. [Figure 9] 2 is a cross-sectional view of the main plate in FIG. 1 cut along a plane including an axis in the first embodiment. [Figure 10] FIG. 2 is an enlarged cross-sectional view of a portion including the inclined surface of the impeller cup and the inner peripheral surface of the main plate in FIG. 1 in the first embodiment, and is a view to help explain the V-shaped recess formed by the inclined surface and the inner peripheral surface of the main plate. [Figure 11]FIG. 7 is a cross-sectional view taken along line XI-XI in FIG. 6 in the first embodiment, and is a cross-sectional view for assisting in the explanation of the impeller inclination angle at a portion of the inclined surface of the impeller cup on the pressure surface side of the blade. [Figure 12] FIG. 7 is a cross-sectional view taken along line XII-XII in FIG. 6 in the first embodiment, and is a cross-sectional view for assisting in the explanation of the impeller inclination angle at a portion of the inclined surface of the impeller cup on the suction surface side of the blade. [Figure 13] FIG. 5 is a partially enlarged view of a portion including the blades and the inclined surface of the impeller cup in FIG. 4 in the first embodiment, showing the inner end portion of the inclined surface of the impeller cup in the radial direction of the fan as viewed from the inside in the radial direction. [Figure 14] FIG. 11 is a diagram showing a shroud, an impeller cup, and a main plate in a centrifugal blower that is a comparative example to the first embodiment, cut along a plane including the fan axis, and is a diagram to assist in explaining constraints for integrally molding the shroud, the impeller cup, a plurality of blades, and the main plate. [Figure 15] FIG. 2 is an enlarged view of a right half of the shroud, impeller cup, and main plate in FIG. 1 with the fan axis as the center line in the first embodiment, and is a cross-sectional view to assist in the description of an undercut region. [Figure 16] FIG. 17 is a diagram to assist in explaining the relationship between the imaginary tangent of the cover region of the shroud in FIG. 15 and the inclined surface of the impeller cup in the first embodiment, and shows a state in which the imaginary tangent and the inclined surface are formed to be parallel to each other. [Figure 17] FIG. 17 is a diagram to assist in explaining the relationship between the imaginary tangent of the cover region of the shroud in FIG. 15 and the inclined surface of the impeller cup in the first embodiment, and shows a state in which the distance between the imaginary tangent and the inclined surface becomes smaller as one moves from the inside to the outside in the fan radial direction. [Figure 18] FIG. 11 is a diagram illustrating two of a plurality of blades in a modified example of the first embodiment, the diagram illustrating the two blades as viewed from one side in the fan axial direction, and the diagram is intended to assist in explaining the shapes of the pressure and suction sides of the two blades. [Figure 19]2 is a flowchart showing details of a manufacturing process for manufacturing the impeller of FIG. 1 in the first embodiment. [Figure 20] 19A to 19C are diagrams for assisting in the explanation of the manufacturing process for integrally molding the plurality of blades, the impeller cup, and the shroud in FIG. 18, and of the mold used in this manufacturing process, in the first embodiment. [Figure 21] FIG. 2 is a cross-sectional view showing the right half of a cross-sectional view of a comparison example of the first embodiment, in which a plurality of blades, an impeller cup, a shroud, and a main plate are cut along a plane including the fan axis, the right half being centered on the fan axis. [Figure 22] FIG. 11 is a view of the main plate and a plurality of blades as viewed from one side in the fan axial direction in the second embodiment. [Diagram 23] FIG. 23 is a cross-sectional view taken along line XXIII-XXIII in FIG. 22 in the second embodiment, and is a cross-sectional view to assist in the explanation of the main plate inclination angle at a portion on the pressure surface side of the main plate inner circumferential surface of the main plate, and the region between the shroud and the main plate. [Figure 24] FIG. 24 is a cross-sectional view taken along line XXIV-XXIV in FIG. 22 in the second embodiment, and is a cross-sectional view to assist in the explanation of the main plate inclination angle at a portion of the inner circumferential surface of the main plate on the negative pressure side, and the region between the shroud and the main plate. [Diagram 25] FIG. 11 is a view of the main plate and a plurality of blades as viewed from one side in the fan axial direction in the third embodiment. [Figure 26] FIG. 26 is a cross-sectional view taken along line XXVI-XXVI in FIG. 25 in the third embodiment, and is a cross-sectional view to assist in the explanation of the main plate inclination angle of the portion of the main plate inner circumferential surface on the negative pressure side, and the region between the shroud and the main plate outer circumferential surface of the main plate. [Figure 27] FIG. 27 is a cross-sectional view taken along line XXVII-XXVII in FIG. 25 in the third embodiment, and is a cross-sectional view to assist in the explanation of the main plate inclination angle of the portion of the main plate inner circumferential surface on the pressure side, and the region between the shroud and the main plate outer circumferential surface of the main plate. [Figure 28] FIG. 28 is a cross-sectional view taken along the line XXVIII in FIG. 25 in the third embodiment, for assisting in the description of the region between the outer peripheral surfaces of the main plates. [Figure 29] FIG. 13 is a partially enlarged view of an impeller cup and a part of a main plate of a centrifugal blower according to another embodiment, and is a partially cross-sectional view to assist in the description of an inner peripheral surface of the main plate. [Diagram 30] FIG. 13 is a partially enlarged view of an impeller cup and a part of a main plate of a centrifugal blower according to another embodiment, and is a partially cross-sectional view to assist in the description of the outer peripheral surface of the main plate. [Diagram 31] FIG. 11 is a partially enlarged view of an impeller cup and a part of a main plate of a centrifugal blower in another embodiment, and is a partially cross-sectional view to assist in the description of the main plate outer peripheral surface and the main plate inner peripheral surface of the main plate. [Diagram 32] FIG. 11 is a partially enlarged view of a portion including a cover region of a shroud and an inclined surface of an impeller cup in another embodiment, and corresponds to FIG. 5 in the first embodiment. [Diagram 33] FIG. 27 is a partial enlarged view of a portion including the inner side in the fan radial direction of the main plate and the outer side in the fan radial direction of the impeller cup in another embodiment, and corresponds to FIG. 27 of the first embodiment. [Diagram 34] FIG. 34 is a partially enlarged view of part XXXIV in FIG. 33 in another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings in order to simplify the description.

[0021] (First embodiment) Hereinafter, a centrifugal blower 10 of this embodiment will be described with reference to Fig. 1, Fig. 2, etc. Fig. 1 is an axial cross-sectional view of a centrifugal blower 10 in this embodiment, taken along a plane including a fan axis Sa.

[0022] An arrow DRa in Fig. 1 indicates the fan axial direction DRa of the fan axis Sa. The fan axial direction DRa is the fan axial direction in which the fan axis Sa extends. An arrow DRr in Fig. 1 indicates the fan radial direction DRr centered on the fan axis Sa. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1, and in Fig. 2, an arrow Edr indicates the circumferential direction Edr centered on the fan axis Sa. In Fig. 2, cross-sectional hatching of multiple blades 60 is omitted for clarity.

[0023] As shown in FIGS. 1 and 2, the centrifugal blower 10 is a turbo-type blower, and includes a casing 12, an electric motor 14, and an impeller 16.

[0024] The casing 12 protects the electric motor 14 and the impeller 16 from dust and dirt outside the centrifugal blower 10. The casing 12 houses the electric motor 14 and the impeller 16. The casing 12 is made of, for example, a resin material. The casing 12 has a generally disk shape with a larger dimension in the fan radial direction DRr than the impeller 16.

[0025] The casing 12 includes a first cover portion 120 and a second cover portion 121. The first cover portion 120 is disposed on one side in the fan axial direction DRa with respect to the impeller 16. The first cover portion 120 is formed so as to cover the impeller 16 from one side in the fan axial direction DRa.

[0026] The first cover portion 120 is formed in a ring shape centered on the fan axis Sa. An air intake port 221a penetrating in the fan axial direction DRa is formed on the inside of the first cover portion 120 in the fan radial direction DRr. The air intake port 221a constitutes an air inlet through which air flows in from one side in the fan axial direction DRa.

[0027] A bellmouth portion 221b is provided on the periphery that defines the air intake port 221a of the first cover portion 120. The bellmouth portion 221b plays a role in smoothly guiding air that flows into the air intake port 221a from one side in the fan axial direction DRa with respect to the centrifugal blower 10, to the intake hole 62a of the shroud 62.

[0028] 1, a first peripheral edge portion 222 is provided on the radially outer side of the first cover portion 120 about the fan axis Sa. The first peripheral edge portion 222 is formed along the circumferential direction Edr.

[0029] The second cover portion 121 is formed in a ring shape centered on the fan axis Sa. The second cover portion 121 is disposed on the other side in the fan axial direction DRa of the multiple blades 60, the shroud 62, and the main plate 64 of the impeller 16. The second cover portion 121 is formed so as to cover the multiple blades 60, the shroud 62, and the main plate 64 from the other side in the fan axial direction DRa.

[0030] A second peripheral edge portion 242 is provided on the radially outer side of the second cover portion 121 about the fan axis Sa. The second peripheral edge portion 242 is formed along the circumferential direction Edr.

[0031] The second peripheral portion 242, together with the first peripheral portion 222, forms an air outlet 12a through which air is blown out from the impeller 16. The air outlet 12a is formed around the entire circumference of the casing 12, centered on the fan axis Sa.

[0032] A plurality of support columns (not shown) are provided between the first peripheral portion 222 and the second peripheral portion 242. The support columns are arranged in the circumferential direction Edr. The support columns connect the first peripheral portion 222 and the second peripheral portion 242.

[0033] 1, the electric motor 14 is disposed on the radially inner side of the second cover portion 121 with respect to the fan axis Sa. The electric motor 14 is an outer rotor type brushless DC motor. In this embodiment, the maximum dimension of the electric motor 14 in the fan radial direction DRr is larger than the maximum dimension of the intake holes 62a of the shroud 62 in the fan radial direction DRr.

[0034] The electric motor 14 includes a rotor 40, a rotating shaft 42, a stator housing 44, a stator coil 46, and bearings 48a, 48b. The rotor 40 includes a rotor cup 140 and a plurality of permanent magnets 144. The rotor cup 140 is made of a magnetic material such as iron and is formed in a generally cylindrical shape centered on the fan axis Sa.

[0035] Specifically, the rotor cup 140 includes a cylindrical portion 142 and a lid portion 143. The cylindrical portion 142 is formed in a cylindrical shape centered on the fan axis Sa. The lid portion 143 is disposed on one side of the cylindrical portion 142 in the fan axial direction DRa.

[0036] The lid portion 143 is formed so as to cover one side of the cylindrical portion 142 in the fan axial direction DRa. Specifically, the lid portion 143 includes a boss portion 143a that constitutes the recess 140a to which the rotating shaft 42 is fixed, and an inclined portion 143b that is disposed between the boss portion 143a and the cylindrical portion 142.

[0037] The inclined portion 143b is inclined toward the other side of the fan axial direction DRa as it moves from the inside of the fan radial direction DRr to the outside of the fan radial direction DRr. As described later, the inclined portion 143b guides the air that flows in through the air intake port 221a and the air intake hole 62a to the outside of the fan radial direction DRr.

[0038] The plurality of permanent magnets 144 are arranged in the circumferential direction Edr on the inner side of the fan radial direction DRr of the cylindrical portion 142. The plurality of permanent magnets 144 are fixed to the inner circumferential surface of the cylindrical portion 142.

[0039] The rotating shaft 42 is formed in a cylindrical shape centered on the fan axis Sa. One end of the rotating shaft 42 in the fan axis direction DRa is fitted into a recess 140a of the rotor cup 140. This means that the rotating shaft 42 is fixed to the rotor cup 140. The rotating shaft 42 is made of a metal material such as iron, stainless steel, or brass.

[0040] The stator housing 44 is formed in a cylindrical shape centered on the fan axis Sa. The stator housing 44 is disposed outside the rotation shaft 42 in the fan radial direction DRr.

[0041] The bearings 48a, 48b are disposed between the stator housing 44 and the rotating shaft 42. The bearings 48a, 48b are aligned in the fan axis direction DRa. The bearings 48a, 48b are supported by the stator housing 44 and support the rotating shaft 42 so as to enable rotation about the fan axis Sa.

[0042] The stator coil 46 includes a plurality of windings each formed of an electric wire, and the plurality of windings are arranged in the circumferential direction Edr. As described below, the stator coil 46 applies a rotating magnetic field to the plurality of permanent magnets 144 of the rotor 40, thereby applying a rotational force to the rotor 40 that rotates the rotor 40 about the fan axis Sa.

[0043] 1, the impeller 16 is a centrifugal impeller applied to the centrifugal blower 10. The impeller 16 rotates about the fan axis Sa in the fan rotation direction DRf, thereby drawing in air through the air intake port 221a from one side of the fan axis direction DRa, as indicated by the arrow FLa.

[0044] In this embodiment, the fan rotation direction DRf means one side of the circumferential direction Edr. The impeller 16 blows out the sucked air radially outward from the fan axis Sa relative to the impeller 16, as indicated by arrow FLb.

[0045] Specifically, the impeller 16 of the present embodiment includes a plurality of blades 60, a shroud 62, a main plate 64, and an impeller cup 66. For ease of explanation, the plurality of blades 60 will also be referred to as blades 60a, 60b, 60c, 60d, 60e, 60g, 60h, 60i, 60j, 60k, 60l, and 60m, as shown in FIG.

[0046] The blades 60 are arranged in the circumferential direction Edr as shown in Figures 1, 2, and 3. As shown in Figure 2, each of the blades 60 has a pressure surface 160a and a suction surface 160b that form a blade shape.

[0047] The positive pressure surface 160a is formed on one side of the circumferential direction Edr (i.e., the fan rotation direction DRf) in each of the plurality of blades 60. The positive pressure surface 160a is a surface on which positive pressure acts in each of the plurality of blades 60 when the impeller 16 rotates in the fan rotation direction DRf.

[0048] The negative pressure surface 160b is formed on the other side in the circumferential direction Edr of each of the plurality of blades 60. The negative pressure surface 160b is a surface on which negative pressure acts in each of the plurality of blades 60 when the impeller 16 rotates in the fan rotation direction DRf.

[0049] Specifically, as shown in FIG. 3, in each of the blades 60, the radially inner side about the fan axis Sa is located within the air intake port 221a.

[0050] As shown in Fig. 2, an air flow passage 68 through which air flows is formed between the main plate 64 and the impeller cup 66 and the shroud 62, and between two adjacent blades 52 among the plurality of blades 52. That is, the air flow passage 68 is formed between the positive pressure surface 160a of the blade 60 on the other side in the circumferential direction Edr among the two adjacent blades 60 among the plurality of blades 60, and the negative pressure surface 160b of the blade 60 on one side in the circumferential direction Edr among the two blades 60. The air flow passage 68 is formed between the main plate 64 and the shroud 62. The air flow passage 68 is formed between the impeller cup 66 and the shroud 62.

[0051] In this embodiment, the positive pressure surface 160a of one of the two blades 60 and the negative pressure surface 160b of the other blade 60 are formed to extend along the fan radial direction DRr via an air flow passage 68.

[0052] Each of the blades 60 is connected to a shroud 62 as shown in Fig. 1. The blades 60 are connected to an impeller cup 66 as shown in Figs. 4, 7, and 8. The blades 60, the shroud 62, and the impeller cup 66 are made of a resin material. The blades 60, the shroud 62, and the impeller cup 66 form an integrated structure that is integrated using a slide mold, as described below.

[0053] In this embodiment, the constraints imposed when molding the blades 60, the shroud 62, and the impeller cup 66 using a slide mold will be described later.

[0054] 1, the shroud 62 has a disk-like shape that expands in the fan radial direction DRr. The shroud 62 is formed so as to cover the multiple blades 60 from one side in the fan axial direction DRa. The shroud 62 supports the multiple blades 60 from one side in the fan axial direction DRa.

[0055] An intake hole 62a through which air is drawn from the air intake port 221a of the casing 12 as indicated by an arrow FLa is formed on the inside of the shroud 62 in the fan radial direction DRr. Therefore, the shroud 62 has a ring shape.

[0056] 1 and 4, the shroud 62 has a ring inner circumferential end portion 621 and a ring outer circumferential end portion 622. The ring inner circumferential end portion 621 is an end portion provided on the inside in the fan radial direction DRr of the shroud 62. The ring inner circumferential end portion 621 forms an intake hole 62a.

[0057] The ring outer peripheral end 622 is an end provided on the outer side in the fan radial direction DRr of the shroud 62. The ring outer peripheral end 622, together with the plurality of blades 60 and the main plate 64, forms air outlets 68a of each of the plurality of air flow paths 68.

[0058] As shown in FIG. 1, the shroud 62 is formed in an inclined shape so as to progress toward one side in the fan axial direction DRa from the ring outer circumferential end 622 toward the ring inner circumferential end 621.

[0059] Specifically, a cover region 62b is provided on the other side of the shroud 62 in the fan axial direction DRa, which is a region that overlaps with the impeller cup 66 in the fan axial direction DRa. The cover region 62b is formed in an arc shape that protrudes toward the other side in the fan axial direction DRa in the cross-sectional views shown in Figures 1 and 15. Figure 15 is a partial enlarged view of a portion including the shroud 62 and the impeller cup 66 in Figure 1.

[0060] As shown in FIG. 15, the shroud 62 is formed so as to be inclined from an outer end 62d of the cover region 62b in the fan radial direction DRr toward a ring inner circumferential end 621 so as to progress to one side in the fan axial direction DRa.

[0061] This makes it possible to prevent the air flowing into the multiple air passages 68 from separating from the shroud 62 .

[0062] The shroud 62 is covered from one side in the fan axial direction DRa by the first cover portion 120 of the casing 12. The shroud 62 constitutes a path forming portion 62f that forms a maze-shaped gap 62c between itself and the path forming portion 120a of the first cover portion 120, as shown in FIG.

[0063] In this embodiment, a labyrinth mechanism that prevents air from flowing through the gap 62c between the shroud 62 and the first cover portion 120 is configured.

[0064] 1, the impeller cup 66 is formed in a cylindrical shape centered on the fan axis Sa. The impeller cup 66 is disposed on the inside of the second cover part 121 in the fan radial direction DRr. The impeller cup 66 is a tubular part disposed on the inside of the main plate 64 in the fan radial direction DRr. In other words, the impeller cup 66 is disposed within the opening 64a of the main plate 64. The impeller cup 66 is disposed outside the rotor cup 140 of the rotor 40 of the electric motor 14 in the fan radial direction DRr. The impeller cup 66 is supported by the rotor cup 140 of the rotor 40 of the electric motor 14. For this reason, the impeller cup 66 is configured to be rotatable about the fan axis Sa by the rotational force of the electric motor 14.

[0065] 1 and 5, an inclined surface 67 is formed as an end face on one side of the impeller cup 66 in the fan axial direction DRa. The inclined surface 67 is formed in an inclined shape so as to progress from the inside to the outside in the fan radial direction DRr toward the other side in the fan axial direction DRa.

[0066] The inclined surface 67 is formed over the circumferential direction Edr. The inclined surface 67 is disposed so as to overlap with the pressure surface 160a and the suction surface 160b of each of the plurality of blades 60 in the fan axial direction DRa.

[0067] In this embodiment, an outer end portion 67a of the inclined surface 67 shown in FIG. 2 in the fan radial direction DRr is disposed at the same position in the fan axial direction DRa over the circumferential direction Edr.

[0068] As will be described later, the position of an inner end portion 67b of the inclined surface 67 in the fan radial direction DRr varies in the fan axial direction DRa depending on the position in the circumferential direction Edr.

[0069] In this embodiment, as shown in Figs. 7 and 8, a connecting portion 70 connected to the plurality of blades 60 is formed in a region of the impeller cup 66 that overlaps with the plurality of blades 60 in the fan axial direction DRa.

[0070] The connecting portion 70 is provided on the impeller cup 66 on the inner side of the inclined surface 67 in the fan radial direction DRr.

[0071] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 7 is a cross-sectional view taken along line VIII-VIII in FIG. 6. FIG. 8 ...6 is a cross-sectional view taken along line VIII-VIII in FIG. 2. FIG. 6 is a partial enlarged view taken along line VIII-VIII in FIG. 2. In FIG. 6, the cross-sectional hatching of the blades 60c and 60d is omitted for clarity.

[0072] 9, the main plate 64 has an opening 64a penetrating in the fan axial direction DRa and is formed in a ring shape centered on the fan axis Sa. The main plate 64 is provided on the outer side of the impeller cup 66 in the fan radial direction DRr. The main plate 64 is formed so as to cover the multiple blades 60 from the other side in the fan axial direction DRa.

[0073] Specifically, as shown in FIG. 9 , the main plate 64 has a main plate outer peripheral surface 170 formed in a ring shape centered on the fan axis Sa, and a main plate inner peripheral surface 171 arranged inside the main plate outer peripheral surface 170 in the fan radial direction DRr.

[0074] The main plate outer peripheral surface 170 is a main plate flow passage surface that is disposed on the outside of the inclined surface 67 of the impeller cup 66 in the fan radial direction DRr. The main plate outer peripheral surface 170 is disposed on one side in the fan axial direction DRa of the outer end portion 67a of the inclined surface 67 in the fan radial direction DRr. The main plate outer peripheral surface 170 is formed over the circumferential direction Edr. The main plate outer peripheral surface 170 is disposed on the other side in the fan axial direction DRa of the shroud 62. The main plate outer peripheral surface 170, together with the plurality of blades 60 and the shroud 62, forms a plurality of air flow passages 68.

[0075] The main plate inner peripheral surface 171 is disposed between the main plate outer peripheral surface 170 and the inclined surface 67 of the impeller cup 66. The main plate inner peripheral surface 171 is an inner peripheral inclined surface that is inclined toward one side in the fan axial direction DRa as it moves from the inside in the fan radial direction DRr to the outside in the fan radial direction DRr. The main plate inner peripheral surface 171 is formed over the circumferential direction Edr. The main plate inner peripheral surface 171, together with the inclined surface 67 of the impeller cup 66, forms a V-shaped recess that is recessed toward the other side in the fan axial direction DRa.

[0076] In this embodiment, the main plate inner peripheral surface 171 serves to guide the air flowing along the inclined surface 67 of the impeller cup 66 to the main plate outer peripheral surface 170 .

[0077] As shown in FIG. 10, the inner side of the main plate 64 in the fan radial direction DRr forms a stepped shape having inner circumferential surfaces 180, 181 and a radial surface 182.

[0078] The inner circumferential surfaces 180, 181 are arranged offset from each other in the fan radial direction DRr and are formed along the fan axial direction DRa. The inner circumferential surfaces 180, 181 are each formed along the circumferential direction Edr. The inner circumferential surface 180 is arranged outward of the inner circumferential surface 181 in the fan radial direction DRr and on one side in the fan axial direction DRa.

[0079] The radial surface 182 is a second radial surface that is formed in the fan radial direction DRr. The radial surface 182 is formed in the circumferential direction Edr. The radial surface 182 is disposed between the inner circumferential surfaces 180, 181.

[0080] The outer side of the impeller cup 66 in the fan radial direction DRr forms a stepped shape having outer peripheral surfaces 190 and 191 and a radial surface 192.

[0081] The outer peripheral surfaces 190, 191 are arranged offset from each other in the fan radial direction DRr and are formed along the fan axial direction DRa. The outer peripheral surfaces 190, 191 are each formed along the circumferential direction Edr. The outer peripheral surface 190 is arranged outward of the outer peripheral surface 191 in the fan radial direction DRr and on one side in the fan axial direction DRa.

[0082] The radial surface 192 is a first radial surface that is formed in the fan radial direction DRr. The radial surface 192 is formed in the circumferential direction Edr. The radial surface 192 is disposed between the outer circumferential surfaces 190 and 191.

[0083] In this embodiment, the inner side of the main plate 64 in the fan radial direction DRr and the outer side of the impeller cup 66 in the fan radial direction DRr are fitted together. This connects the impeller cup 66 to the main plate 64 so as to be unable to move relative to the main plate 64.

[0084] The inner peripheral surface 180 and the outer peripheral surface 190 face each other via a gap 200 (i.e., a first gap). The inner peripheral surface 181 and the outer peripheral surface 191 face each other via a gap 201 (i.e., a first gap). The radial surfaces 182, 192 face each other via a gap 202 (i.e., a second gap).

[0085] The gaps 200, 201, and 202 form a labyrinth-shaped air flow path between the inner side of the main plate 64 in the fan radial direction DRr and the outer side of the impeller cup 66 in the fan radial direction DRr.

[0086] As a result of the above, a labyrinth structure is formed that prevents air from flowing between the inner side of the main plate 64 in the fan radial direction DRr and the outer side of the impeller cup 66 in the fan radial direction DRr.

[0087] Next, details of the inclined surface 67 of the impeller cup 66 of this embodiment will be described with reference to FIGS. 2, 7, 8, 11, 12, and 13. FIG.

[0088] First, as shown in Figures 11 and 12, in a cross section of the impeller cup 66 cut by a plane including the fan axis Sa, the narrow angle formed between the inclined surface 67 and a virtual plane 210 perpendicular to the fan axis Sa is defined as the impeller inclination angle θ.

[0089] Here, the narrow angle is the smaller angle θ out of the two angles θ and β formed between the imaginary surface 210 and the inclined surface 67, as shown in FIGS.

[0090] Fig. 8 is a cross-sectional view of the vicinity of the pressure surface 160a of the blade 60d in the region of the impeller cup 66 where the blade 60d overlaps with the fan axial direction DRa. Fig. 7 is a cross-sectional view of the vicinity of the suction surface 160b of the blade 60c in the region of the impeller cup 66 where the blade 60c overlaps with the fan axial direction DRa.

[0091] FIG. 11 is a cross-sectional view of the vicinity of pressure side 160a of blade 60c at intermediate slope 168 between pressure side 160a of blade 60d and suction side 160b of blade 60c.

[0092] FIG. 12 is a cross-sectional view of the vicinity of suction side 160b of blade 60d at an intermediate inclined portion 168 between suction side 160b of blade 60c and suction side 160b of blade 60d.

[0093] The intermediate inclined portion 168 in this embodiment is a region of the inclined surface 67 formed between two adjacent blades among the plurality of blades 60. That is, the inclined surface 67 constitutes a plurality of intermediate inclined portions 168. For example, the intermediate inclined portion 168 between the blades 60c and 60d is a region of the inclined surface 67 formed from the blade 60d to the blade 60c in the fan rotation direction DRf.

[0094] The impeller inclination angle θ in Figures 8 and 11 is the impeller inclination angle of the portion of the inclined surface 67 on the side of the positive pressure surface 160a of the blade 60d in the circumferential direction Edr. The impeller inclination angle θ in Figures 7 and 12 is the impeller inclination angle of the portion of the inclined surface 67 on the side of the negative pressure surface 160b of the blade 60c in the circumferential direction Edr.

[0095] Here, the outer end 67a of the inclined surface 67 in the fan radial direction DRr is disposed at the same position in the fan radial direction DRr over the circumferential direction Edr. The outer end 67a of the inclined surface 67 in the fan radial direction DRr is disposed at the same position in the fan axial direction DRa over the circumferential direction Edr.

[0096] In the multiple intermediate inclined portions 168 of the inclined surface 67, the inner end portions 67b of the inclined surface 67 in the fan radial direction DRr are arranged at the same position in the fan radial direction DRr over the circumferential direction Edr.

[0097] As shown in Figure 13, the inner end 67b of the inclined surface 67 in the fan radial direction DRr is located on the other side in the fan axial direction DRa of the inclined surface 67 on the positive pressure surface 160a side of the blade 60d compared to the negative pressure surface 160b side of the inclined surface 67 on the blade 60c. Here, the inner end 67b of the inclined surface 67 is formed so as to gradually progress to one side in the fan axial direction DRa as it progresses from the positive pressure surface 160a side of the blade 60d to the negative pressure surface 160b side of the blade 60c in the fan rotation direction DRf.

[0098] Reference numeral 167a in Fig. 13 denotes an end portion of the inner end portion 67b on the suction surface 160b side of the blade 60c. Reference numeral 167b in Fig. 13 denotes an end portion of the inner end portion 67b on the pressure surface 160a side of the blade 60d.

[0099] Here, as shown in FIG. 15, the flow passage cross-sectional area is defined as the area of ​​a cross section of the undercut region 220 of the air passage 68 formed between the inclined surface 67 of the impeller cup 66 and the shroud 62, cut by a plane including the fan axis Sa.

[0100] In the intermediate inclined portion 168 between the blades 60d and 60c, the impeller inclination angle θ gradually increases from the pressure surface 160a of the blade 60d to the suction surface 160b of the blade 60c in the fan rotation direction DRf. This causes the flow path cross-sectional area to gradually decrease from the pressure surface 160a of the blade 60d to the suction surface 160b of the blade 60c in the fan rotation direction DRf.

[0101] Therefore, in the intermediate inclined portion 168 between the blades 60d and 60c, the flow velocity of the air flowing on the pressure surface 160a side of the blade 60d can be reduced, and the flow velocity of the air flowing on the suction surface 160b of the blade 60c can be increased. This makes it possible to reduce the flow side difference between the flow velocity of the air flowing on the pressure surface 160a side of the blade 60d and the flow velocity of the air flowing on the suction surface 160b of the blade 60c. This makes it possible to suppress the generation of noise caused by the flow side difference.

[0102] The inclined shape of the intermediate inclined portion 168 between the blades 60d, 60c is formed in the same manner in the other intermediate inclined portions 168 among the plurality of intermediate inclined portions 168 other than the intermediate inclined portion 168 between the blades 60d, 60c.

[0103] Next, the constraints imposed when molding the blades 60, the shroud 62, and the impeller cup 66 using a slide mold in this embodiment will be described with reference to FIGS. 6, 15, 16, and 17. FIG.

[0104] First, it is possible to integrally mold the plurality of blades 60, the shroud 62, the impeller cup 66, and the main plate 64 using a slide mold, as shown in Fig. 14. The illustration of the plurality of blades 60 is omitted in Fig. 14. In this case, for example, it is necessary to make it possible to slide the slide mold 93x radially inward relative to the shroud 62, the plurality of blades 60, and the main plate 64 and remove them.

[0105] In this case, as shown in FIG. 14, a shape in which the shroud 62 and the main plate 64 have an inclination angle θd of 0 degrees or more is required.

[0106] FIG. 14 is a cross-sectional view of the centrifugal blower cut along a plane including the fan axis Sa. A dashed line 64y in FIG. 14 is an imaginary plane obtained by translating a surface 64x of a main plate 64 in one direction along the fan axis.

[0107] However, depending on the shape of the main plate 64, there are cases where an inclination angle θd of 0 degrees or more cannot be realized.

[0108] In contrast, in this embodiment, in order to allow the air taken in through the intake holes 62a to smoothly flow into the air flow path 68, the shroud 62 is configured as shown in Fig. 15. That is, the shroud 62 is formed so as to progress toward one side in the fan axial direction DRa from the outer end 62d in the fan radial direction DRr toward the inner end 62e of the cover region 62b.

[0109] 16 and 17, a line perpendicular to the fan axial direction DRa and perpendicular to the fan radial direction DRr is defined as an imaginary line 230. The imaginary line 230 is a first imaginary line perpendicular to the paper surface in FIGS.

[0110] Furthermore, a tangent line that is perpendicular to the imaginary line 230 and is tangent to the cover area 62b is defined as an imaginary tangent line 162b (ie, a second imaginary line).

[0111] As shown in FIG. 16, the cover area 62b and the inclined surface 67 are formed so that the inclined surface 67 and the imaginary tangent line 162b are parallel to each other.

[0112] Alternatively, as shown in FIG. 17, the cover area 62b and the inclined surface 67 are formed so that the distance ZL in the fan axial direction DRa between the inclined surface 67 and the imaginary tangent 162b increases from the inner side in the fan radial direction DRr toward the outer side in the fan radial direction DRr.

[0113] As shown in Fig. 18, the outer end portion of each of the blades 60 in the fan radial direction DRr is referred to as an outer end portion 61h. The inner end portion of each of the blades 60 in the fan radial direction DRr is referred to as an inner end portion 61e. In Fig. 18, cross-sectional hatching of the blades 60c and 60d is omitted for clarity.

[0114] The pressure surface 160a and the suction surface 160b are formed such that the distance XR between the blades 60 increases from the inner end 61e to the outer end 61h. The distance XR between the blades 60 is the distance between the pressure surface 160a and the suction surface 160b.

[0115] In this embodiment, as shown in FIG. 18, the positive pressure surface 160a is formed in an arc shape that is convex on one side in the circumferential direction Edr when viewed from the fan axial direction DRa.

[0116] The negative pressure surface 160b is formed in an arc shape that is convex on one side in the circumferential direction Edr when viewed from the fan axial direction DRa. In Fig. 18, cross-sectional hatching of the blades 60c and 60d is omitted for clarity.

[0117] In this manner, the plurality of blades 60, the shroud 62, and the impeller cup 66 are configured. Therefore, the plurality of blades 60, the shroud 62, and the impeller cup 66 can be integrally molded by die molding using a slide mold.

[0118] Next, the manufacturing process of the impeller 16 will be described with reference to the flowchart in Fig. 19. As shown in Fig. 19, first, in step S01, a plurality of blades 60, a shroud 62, and an impeller cup 66 are formed.

[0119] Specifically, as shown in FIG. 20, a plurality of blades 60, a shroud 62, and an impeller cup 66 are integrally formed by injection molding using a mold.

[0120] The mold includes a cavity mold, a core mold, and a plurality of slide dies 93. The cavity mold and the core mold are configured to be able to open and close in the fan axial direction DRa. The core mold is a mold provided on the other side of the cavity mold in the fan axial direction DRa.

[0121] A plurality of slide dies 93 are prepared to form an undercut region 220 formed between the impeller cup 66 and the shroud 62. A plurality of slide dies 93 are prepared in a number equal to the number of air flow passages 69.

[0122] First, in the molding process of step 01, a molten resin material is injected between the cavity mold and the core mold with a plurality of slide molds 93 arranged between them. After that, the resin material is cooled and solidified to form an integrated component 94 between the cavity mold and the core mold.

[0123] Furthermore, the cavity mold and the core mold are separated in the fan axial direction DRa, and the integrated component 94 and the plurality of slide dies 93 are taken out from between the cavity mold and the core mold. At this time, the plurality of slide dies 93 are slid outward in the fan radial direction DRr along the positive pressure surface 160a and the negative pressure surface 160b of two adjacent blades 60 among the plurality of blades 60.

[0124] Thereafter, the multiple slide dies 93 are slid outward in the fan radial direction DRr and to the other side in the fan axial direction DRa as indicated by the arrow Su from the integrated component 94. As a result, the multiple slide dies 93 are separated from the integrated component 94.

[0125] As a result, the molding of the integrated structure 94 that integrates the multiple blades 60, the shroud 62, and the impeller cup 66 is completed.

[0126] Next, in the molding process of step 02, the main plate 64 is molded by resin molding using a metal mold.

[0127] Next, in the joining process of step 03, the inner side of the main plate 64 in the fan radial direction DRr and the outer side of the impeller cup 66 in the fan radial direction DRr are fitted together to join the plurality of blades 60 to the main plate 64 by adhesive. This completes the formation of the impeller 16.

[0128] Next, the operation of the centrifugal blower 10 of this embodiment will be described.

[0129] First, in the electric motor 14, when a three-phase AC current flows through the stator coil 46, a rotating magnetic field is generated in the stator coil 46. Accordingly, the rotor 40 rotates due to the rotating magnetic field. At this time, the rotor 40 applies a rotational force to the impeller 16 via the impeller cup 66. As a result, the impeller 16 rotates in the fan rotation direction DRf.

[0130] At this time, air flowing in through the air intake port 221a of the casing 12 from one side in the fan axial direction DRa is sucked into the intake hole 62a as indicated by the arrow FLa.

[0131] A portion of this drawn air flows into each of the multiple air flow paths 68 .

[0132] Here, the cover region 62b of the shroud 62 is formed in an arc shape that is convex toward the other side in the fan axial direction DRa. Therefore, the air drawn into the intake holes 62a flows along the shroud 62 to the outside in the fan radial direction DRr without being separated from the shroud 62.

[0133] In addition, of the air sucked into the intake hole 62a, the remaining air other than the portion that flows along the shroud 62 flows along the inclined portion 143b of the rotor cup 140, the inclined surface 67 of the impeller cup 66, the main plate inner surface 171, and the main plate outer surface 170.

[0134] The air flowing in each of the plurality of air flow paths 68 in this manner flows outward in the fan radial direction DRr due to centrifugal force. Then, this flowing air passes through the air outlet 68a and is blown out from the air outlet 12a as indicated by arrow FLb.

[0135] According to the present embodiment described above, the centrifugal blower 10 forms an integrated component 94 in which a plurality of blades 60, a shroud 62, and an impeller cup 66 are integrally formed, and the impeller cup 66 is fitted to the main plate 64.

[0136] The other side of the shroud 62 in the fan axial direction has a cover region 62b formed so as to cover one side of the impeller cup 66 in the fan axial direction. The cover region 62b is formed in an arc shape that protrudes toward the other side in the fan axial direction DRa in a cross-sectional view of the shroud 62 cut along a plane including the fan axis Sa.

[0137] Here, the shroud 62 is formed so as to progress toward one side in the fan axial direction DRa from an outer end 62d in the fan radial direction DRr of the cover region 62b toward a ring inner circumferential end 621 in the fan radial direction DRr.

[0138] The impeller cup 66 is provided on one side in the fan axial direction DRa with an inclined surface 67 that is formed so as to progress toward one side in the fan axial direction DRa from the outer side toward the inner side in the fan radial direction DRr.

[0139] According to the above, the cover region 62b is formed in an arc shape that is convex toward the other side in the fan axial direction DRa in a cross section of the shroud 62 cut along a plane including the fan axis Sa. The shroud 62 is formed to progress toward one side in the fan axial direction DRa from the outer end 62d of the cover region 62b in the fan radial direction DRr toward the ring inner circumferential end 621 of the shroud 62 in the fan radial direction DRr. Therefore, the air drawn in through the intake holes 62a can flow from the ring inner peripheral end 621 of the shroud 62 along the outer end 62d of the cover region 62b. This makes it possible to suppress the generation of noise that occurs when air flows into the air flow path 68.

[0140] Here, as shown in FIG. 21, when the impeller cup 66a and the main plate 64 are integrated, the distance XM between the impeller cup 66a and the main plate 64 and the shroud 62 may become larger from the inside to the outside in the fan radial direction DRr.

[0141] In this case, it may be impossible to slide the impeller cup 66a and the slide mold 93A between the main plate 64 and the shroud 62 inward in the fan radial direction to remove them.

[0142] In contrast, in this embodiment, the shroud 62 is formed so as to progress toward one side in the fan axial direction DRa from an outer end 62d in the fan radial direction DRr to an inner end 62e in the fan radial direction DRr in the cover region 62b.

[0143] In addition, a tangent line that is perpendicular to the fan axial direction DRa and perpendicular to the fan radial direction DRr and that is tangent to the cover region 62b is defined as a virtual tangent line 162b.

[0144] The cover area 62b and the inclined surface 67 are formed so that the inclined surface 67 and the imaginary tangent 162b are parallel to each other. Alternatively, the cover area 62b and the inclined surface 67 are formed so that the distance ZL between the inclined surface 67 and the imaginary tangent 162b in the fan axial direction DRa increases from the inner side in the fan radial direction DRr toward the outer side in the fan radial direction DRr. Therefore, when the plurality of blades 60, the shroud 62, and the impeller cup 66 are integrally molded, the following occurs. That is, when forming the undercut region 220 between the cover region 62b and the inclined surface 67, it becomes possible to pull the slide die 93 out from between the cover region 62b and the inclined surface 67 to the outside in the fan radial direction DRr.

[0145] As a result, it is possible to integrally mold the shroud 62, the blades 60, and the impeller cup 66, excluding the main plate 64, using a slide mold while suppressing the generation of noise.

[0146] According to this embodiment configured as above, the following advantages can be obtained: (1)(2)(3)(4)(5)(6). (1) The inclined surface 67 of the impeller cup 66 is formed so as to progress toward the other side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr. Therefore, the air taken in through the intake hole 62a can flow smoothly radially outward through the cover area 62b and the inclined surface 67. This makes it possible to suppress the generation of noise that occurs when air flows into the air flow path 68.

[0147] (2) On the pressure surface 160a and the suction surface 160b, the distance XR between the blades 60 increases from the inner end 61e to the outer end 61h.

[0148] Therefore, it becomes possible to easily pull the slide die 93 out from between the cover region 62b and the inclined surface 67 to the outside in the fan radial direction DRr.

[0149] (3) In this embodiment, the main plate 64 is disposed on one side in the fan axial direction DRa with respect to the outer end portion 67a of the inclined surface 67 in the fan radial direction DRr, and has a main plate outer circumferential surface 170 formed along the circumferential direction Edr.

[0150] Here, when the restriction of using a slide type is taken into consideration and the purpose is to reduce noise caused by air flow, it is possible to provide an air outlet 68a between an extension line 167c, which is an extension of the inclined surface 67 to the inside in the fan radial direction DRr, and a virtual tangent line 162b, as shown in Fig. 15. In this case, the air outlet 68a is located on the other side in the fan axial direction DRa with respect to the intake hole 62a. That is, when the air outlet 68a is provided between the extension line 167c and the imaginary tangent line 162b, the distance between the air intake hole 62a and the air outlet 68a becomes larger than in the present embodiment, and the size of the centrifugal blower 10 becomes larger.

[0151] However, the position of the air outlet 68a in the fan axial direction DRa has a large influence on the performance of the centrifugal blower 10. Therefore, the performance of the centrifugal blower 10 varies depending on the position of the air outlet 68a in the fan axial direction DRa. The performance of the centrifugal blower 10 includes noise performance, efficiency, and the like.

[0152] In contrast to this, in this embodiment, the main plate outer circumferential surface 170 of the main plate 64 is disposed on one side in the fan axial direction DRa with respect to the outer end portion 67a of the inclined surface 67 in the fan radial direction DRr, as described above.

[0153] Therefore, there is no need to change the position in the fan axial direction DRa of the air outlet 68a, which contributes greatly to performance, while maintaining the same physical size as the conventional centrifugal blower 10. In other words, according to this embodiment, it is possible to achieve the same performance and physical size as the conventional centrifugal blower while satisfying the constraints of using a slide type.

[0154] (4) The main plate 64 has a main plate inner surface 171 that is disposed between the main plate outer peripheral surface 170 and the inclined surface 67, and is formed along the circumferential direction Edr and progresses toward one side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr.

[0155] Therefore, the air flowing along the inclined surface 67 can be smoothly guided to the main plate outer peripheral surface 170.

[0156] (5) In a cross section of the inclined surface 67 cut by a plane including the fan axis Sa, the narrow angle formed between the inclined surface 67 and an imaginary plane 210 perpendicular to the fan axis Sa is defined as the impeller inclination angle θ.

[0157] The area of ​​a cross section of an undercut region 220 between the shroud 63 and the impeller cup 66 in the air flow passage 68 cut by a plane including the fan axis Sa is defined as the flow passage cross-sectional area.

[0158] Here, the positive pressure surface 160a side of the inclined surface 67 has a radially inner end 67b of the inclined surface 67 disposed on the other side in the fan axial direction Dra compared to the negative pressure surface 160b side of the inclined surface 67. An inner end 67b of the inclined surface 67 is formed so as to gradually progress to one side in the fan axial direction DRa as it progresses from the pressure surface 160a of the blade 60d to the suction surface 160b of the blade 60c in the fan rotation direction DRf.

[0159] Therefore, the impeller inclination angle θ gradually increases from the positive pressure surface 160a toward the negative pressure surface 160b in the circumferential direction Edr, and the flow path cross-sectional area of ​​the undercut region 220 gradually decreases from the positive pressure surface 160a toward the negative pressure surface 160b in the circumferential direction Edr.

[0160] Therefore, the speed of the air flowing on the positive pressure surface 160a side of the undercut region 220 can be reduced, and the speed of the air flowing on the negative pressure surface 160b side of the undercut region 220 can be increased.

[0161] Therefore, it is possible to reduce the difference in speed between the air flow on the positive pressure surface 160a side of the undercut region 220 and the air flow on the negative pressure surface 160b side.

[0162] Here, if a difference in speed occurs between the air flowing on the positive pressure surface 160a side of the undercut region 220 and the air flowing on the negative pressure surface 160b side, noise may be generated due to friction between the two air flows.

[0163] In contrast, in the present embodiment, as described above, it is possible to reduce the difference between the speeds of the two air flows, thereby reducing the generation of noise caused by this difference.

[0164] (6) In the present embodiment, a labyrinth-shaped gap is formed between the inside of the main plate 64 in the fan radial direction DRr and the outside of the impeller cup 66 in the fan radial direction DRr. Therefore, the inside of the main plate 64 in the fan radial direction DRr and the outside of the impeller cup 66 in the fan radial direction DRr form a labyrinth structure. This makes it possible to prevent air from flowing between the inside of the main plate 64 in the fan radial direction DRr and the outside of the impeller cup 66 in the fan radial direction DRr.

[0165] Second embodiment In the centrifugal blower 10 of the second embodiment, an example in which the inclination angle of the main plate inner circumferential surface 171 in the centrifugal blower 10 of the above-mentioned first embodiment is changed will be described with reference to Figs. 22, 23 and 24.

[0166] Fig. 22 is a view of the main plate 64 and the blades 60 as viewed from one side in the fan axial direction DRa. Fig. 23 is a cross-sectional view taken along line XXIII-XXIII in Fig. 22, and Fig. 24 is a cross-sectional view taken along line XXIV-XXIV in Fig. 22. In Fig. 22, cross-sectional hatching of the blades 60 has been omitted for clarity.

[0167] In this embodiment, in a cross section of the main plate 64, cutting the main plate inner circumferential surface 171 by a plane including the fan axis Sa, the narrow angle formed between an imaginary plane 240 perpendicular to the fan axis Sa and the main plate inner circumferential surface 171 is defined as the main plate inclination angle θa. Here, of the angles θa and βa formed between the imaginary plane 240 and the main plate inner circumferential surface 171, the smaller angle is defined as the narrow angle θa.

[0168] As shown in FIGS. 23 and 24, the area of ​​a cross section of a region 174 between the shroud 62 and the main plate 64 of the air flow passage 68 cut by a plane including the fan axis Sa is defined as the flow passage cross-sectional area.

[0169] The main plate inclination angle θa in Fig. 23 is the main plate inclination angle on the pressure surface 160a side of the blade 60l of the main plate inner circumferential surface 171 of the main plate 64 in the circumferential direction Edr. The main plate inclination angle θa in Fig. 24 is the main plate inclination angle on the suction surface 160b side of the blade 60k of the main plate inner circumferential surface 171 of the main plate 64 in the circumferential direction Edr.

[0170] In this embodiment, as described above, the blades 60 are arranged such that the positive pressure surface 160a and the negative pressure surface 160b overlap with the main plate inner circumferential surface 171 of the main plate 64 in the fan axial direction DRa.

[0171] The inner end 173 of the main plate inner circumferential surface 171 in the fan radial direction DRr is disposed at the same position in the fan axial direction DRa along the circumferential direction Edr. The inner end 173 of the main plate inner circumferential surface 171 in the fan radial direction DRr is disposed at the same position in the fan radial direction DRr along the circumferential direction Edr.

[0172] The outer end 172 of the main plate inner circumferential surface 171 in the fan radial direction DRr is disposed at the same position in the fan axial direction DRa throughout the circumferential direction Edr. The outer end 172 of the main plate inner circumferential surface 171 in the fan radial direction DRr is formed such that the position in the fan radial direction DRr moves outward from the negative pressure surface 160b toward the positive pressure surface 160a in the circumferential direction Edr.

[0173] Here, the main plate inclination angle θa gradually increases from the pressure surface 160a of the blade 60l toward the suction surface 160b of the blade 60k toward one side in the circumferential direction Edr. As a result, the flow path cross-sectional area of ​​the region 174 gradually decreases toward one side in the circumferential direction Edr from the pressure surface 160a toward the suction surface 160b. The structure of the main plate 64 having such a main plate inclination angle θa is configured similarly between any two adjacent blades 60 among the multiple blades 60 other than the blades 60l and 60k.

[0174] According to the present embodiment described above, in the centrifugal blower 10, the main plate inclination angle θa of the main plate 64 gradually increases from the positive pressure surface 160a toward the negative pressure surface 160b toward one side in the circumferential direction Edr. As a result, the flow path cross-sectional area of ​​the region 174 gradually decreases from the positive pressure surface 160a toward the negative pressure surface 160b in the circumferential direction Edr. Therefore, the speed of the airflow flowing on the positive pressure surface 160a side of the region 174 can be reduced, and the speed of the airflow flowing on the negative pressure surface 160b side of the region 174 can be increased.

[0175] This makes it possible to reduce the difference in speed between the airflow speed flowing on the positive pressure surface 160a side of region 174 and the airflow speed flowing on the negative pressure surface 160b side of region 174. This makes it possible to reduce noise caused by this difference.

[0176] Third embodiment In the above-described second embodiment, an example has been described in which the flow passage cross-sectional area of ​​the region 174 between the shroud 62 and the main plate 64 is configured to vary depending on the circumferential direction Edr. However, a present embodiment in which the flow passage cross-sectional area of ​​the region 175 between the shroud 62 and the main plate outer peripheral surface 170 of the main plate 64 is configured to vary depending on the circumferential direction Edr will be described with reference to Figures 25, 26, 27, and 28. In Figure 25, cross-sectional hatching of multiple blades 60 is omitted for clarity.

[0177] Fig. 25 is a view of the main plate 64 and the blades 60 as viewed from one side in the fan axial direction DRa. Fig. 26 is a cross-sectional view taken along line XXVI-XXVI in Fig. 25, and Fig. 27 is a cross-sectional view taken along line XXVII-XXVII in Fig. 25. Fig. 28 is a view taken along arrow XXVIII in Fig. 25.

[0178] In this embodiment, in a cross section of the main plate 64 cut by a plane including the fan axis Sa, the narrow angle formed between an imaginary plane 240 perpendicular to the fan axis Sa and the main plate inner circumferential surface 171 is defined as the main plate inclination angle θb. Here, of the angles θb and βb formed between the imaginary plane 240 and the main plate inner circumferential surface 171, the smaller angle θb is referred to as the narrow angle.

[0179] As shown in Figures 26 and 27, the area of ​​a cross section of a region 175 of the air flow passage 68 between the shroud 62 and the main plate outer peripheral surface 170 of the main plate 64, cut by a plane including the fan axis Sa, is defined as the flow passage cross-sectional area.

[0180] The main plate inclination angle θb in Fig. 26 is the main plate inclination angle on the negative pressure surface 160b side of the blade 60l of the main plate inner circumferential surface 171 of the main plate 64 in the circumferential direction Edr. The main plate inclination angle θb in Fig. 27 is the main plate inclination angle on the positive pressure surface 160a side of the blade 60k of the main plate inner circumferential surface 171 of the main plate 64 in the circumferential direction Edr.

[0181] In this embodiment, as described above, the blades 60 are arranged such that the positive pressure surface 160a and the negative pressure surface 160b overlap with the main plate inner circumferential surface 171 and the main plate outer circumferential surface 170 of the main plate 64 in the fan axial direction DRa.

[0182] The inner end 173 of the main plate inner circumferential surface 171 in the fan radial direction DRr is disposed at the same position in the fan axial direction DRa along the circumferential direction Edr. The inner end 173 of the main plate inner circumferential surface 171 in the fan radial direction DRr is disposed at the same position in the fan radial direction DRr along the circumferential direction Edr.

[0183] As shown in Fig. 28, the outer end 172 of the main plate inner circumferential surface 171 in the fan radial direction DRr is formed so as to move toward one side of the fan axial direction DRa from the positive pressure surface 160a toward the negative pressure surface 160b in the circumferential direction Edr. The outer end 172 of the main plate inner circumferential surface 171 in the fan radial direction DRr is formed so that the position of the fan radial direction DRr is the same across the circumferential direction Edr. The main plate inclination angle θb gradually decreases as it moves toward one side of the circumferential direction Edr from the positive pressure surface 160a of the blade 60l toward the negative pressure surface 160b of the blade 60k.

[0184] The main plate outer peripheral surface 170 is formed so as to gradually advance toward one side in the fan axial direction DRa from the pressure surface 160a of the blade 60l toward the suction surface 160b of the blade 60k in the circumferential direction Edr. As a result, the flow path cross-sectional area of ​​the region 175 gradually decreases toward one side in the circumferential direction Edr from the pressure surface 160a of the blade 60l toward the suction surface 160b.

[0185] The structure of the main plate 64 having the flow passage cross-sectional area of ​​the region 175 is similarly configured between any two adjacent blades 60 among the plurality of blades 60 other than the blades 60l and 60k.

[0186] According to the present embodiment described above, the main plate 64 of the centrifugal blower 10 is formed such that the main plate outer peripheral surface 170 gradually advances toward one side in the fan axial direction DRa as it advances from the positive pressure surface 160a toward the negative pressure surface 160b toward one side in the circumferential direction Edr. As a result, the flow path cross-sectional area of ​​the region 175 gradually decreases as it advances toward one side in the circumferential direction Edr from the positive pressure surface 160a toward the negative pressure surface 160b.

[0187] Therefore, it is possible to reduce the speed of the airflow flowing on the positive pressure surface 160a side of region 175 and increase the speed of the airflow flowing on the negative pressure surface 160b side of region 175. Therefore, it is possible to reduce the difference in speed between the airflow flowing on the positive pressure surface 160a side of region 175 and the airflow flowing on the negative pressure surface 160b side of region 175. This makes it possible to reduce the generation of noise caused by this difference.

[0188] (Other embodiments) (1) In the above first to third embodiments, an example was described in which the main plate 64 and the impeller cup 66 are fitted together to connect the impeller cup 66 so that the impeller cup 66 cannot move relative to the main plate 64. However, instead of this, the impeller cup 66 may be connected to the main plate 64 in the manner as shown in (a) or (b).

[0189] (a) In order to connect the impeller cup 66 so that it cannot move relative to the main plate 64, the main plate 64 and the impeller cup 66 may be bonded together with an adhesive.

[0190] (b) In order to connect the impeller cup 66 so that it cannot move relative to the main plate 64, the main plate 64 and the impeller cup 66 may be welded together as shown in Figures 32, 33 and 34. In the specific example shown in Figure 32, the main plate 64 is welded to the impeller cup 66 at a joint 630 on the inner side in the fan radial direction DRr and on one side in the fan axial direction DRa. Figure 32 is a partial enlarged view of a portion including the main plate inner circumferential surface 171 of the main plate 64 and the inclined surface 67 of the impeller cup 66. In this case, a protrusion 630a that protrudes to one side in the fan axial direction DRa, as indicated by the dashed line in FIG. 32, is formed on the inner side of the main plate 64 in the fan radial direction DRr before welding. Meanwhile, before welding, in a state in which the main plate 64 is assembled with the impeller cup 66, the outer portion of the impeller cup 66 in the fan radial direction DRr is formed so as to be interfered with by the protrusion 630a of the main plate 64, as shown by the dashed line in Figure 32. Then, the outer portion of the impeller cup 66 in the fan radial direction DRr is welded to the protrusion 630a of the main plate 64 to form a joint 630. In the specific example shown in Figures 33 and 34, the inside of the main plate 64 in the fan radial direction DRr and the other side in the fan axial direction DRa is welded to the impeller cup 66 at a joint 631. Figure 33 is a partial enlarged view of a portion including the inside of the main plate 64 in the fan radial direction DRr and the outside of the impeller cup 66 in the fan radial direction DRr. Figure 34 is a partial enlarged view of part XXXIV in Figure 33. In this case, before welding, the impeller cup 66 has a protrusion 631a formed on the outer side in the fan radial direction DRr, as shown by the dashed line in FIG. 33, which protrudes toward the other side in the fan axial direction DRa. Before welding, when the main plate 64 is assembled to the impeller cup 66, the inner portion of the main plate 64 in the fan radial direction DRr is formed so as to interfere with the protrusion portion 631a of the impeller cup 66, as shown by the dashed lines in Figures 33 and 34. Then, the protrusion 631 a of the impeller cup 66 is welded to the main plate 64 to form a joint 631 .

[0191] (2) In the above first to third embodiments, an example has been described in which the main plate 64 is configured by the main plate outer peripheral surface 170 and the main plate inner peripheral surface 171. However, instead of this, the main plate 64 may be configured as shown in (c), (d), or (e).

[0192] 29, the main plate 64 is constituted by a main plate outer peripheral surface 170 and a main plate inner peripheral surface 171. The main plate inner peripheral surface 171 includes a main plate inclined surface 171a and a main plate orthogonal surface 171b.

[0193] The main plate inclined surface 171a is formed so as to progress to one side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr. The main plate inclined surface 171a is formed throughout the fan axial direction DRa.

[0194] The main plate orthogonal surface 171b is disposed on the other side of the main plate inclined surface 171a in the fan axial direction DRa. The main plate orthogonal surface 171b is formed along the fan axial direction DRa. The main plate orthogonal surface 171b is formed along the circumferential direction Edr.

[0195] (d) As shown in Fig. 30, the main plate 64 is made up of a main plate outer peripheral surface 170 and a main plate inner peripheral surface 171. The main plate outer peripheral surface 170 is formed to extend along the fan axial direction DRa. The main plate inner peripheral surface 171 is formed to progress to one side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr.

[0196] (e) As shown in Fig. 31, the main plate 64 is composed of a main plate outer peripheral surface 170 and a main plate inner peripheral surface 171. The main plate outer peripheral surface 170 is formed so as to smoothly progress to one side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr. The main plate inner peripheral surface 171 is formed so as to smoothly progress to one side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr.

[0197] (3) In the above first, second and third embodiments, the blades 60, the shroud 62 and the impeller cup 66 are integrally molded from a resin material. However, the blades 60, the shroud 62 and the impeller cup 66 may be integrally molded from a metal material other than the resin material.

[0198] (4) In the above first to third embodiments, an example was described in which the two outer circumferential surfaces 190, 191 were provided on the outer side of the impeller cup 66 in the fan radial direction DRr.

[0199] Without being limited to this, as long as a labyrinth structure is formed between the inside of the main plate 64 in the fan radial direction DRr and the outside of the impeller cup 66 in the fan radial direction DRr, three or more outer peripheral surfaces may be provided on the outside of the impeller cup 66 in the fan radial direction DRr.

[0200] In this case, three or more inner circumferential surfaces are formed on the inside of the main plate 64 in the fan radial direction DRr.

[0201] (5) In the above first to third embodiments, an example has been described in which the end face of the impeller cup 66 formed on one side in the fan axial direction DRa is the inclined face 67. The inclined face 67 is an end face that is formed so as to progress toward the other side in the fan axial direction DRa as it moves from the inside to the outside in the fan radial direction DRr. However, instead of this, an end face of the impeller cup 66 formed on one side in the fan axial direction DRa may be a flat surface perpendicular to the fan axial direction DRa. (6) In the above first to third embodiments, an example was described in which the cover area 62b was formed in an arc shape that convex on the other side in the fan axial direction DRa, but this is not limited to the above, and the shape of the cover area 62b is not limited to an arc shape and may be any arc shape. (7) Note that the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the claims. The above-described embodiments are not unrelated to each other, and can be combined as appropriate, except in cases where the combination is clearly impossible. It goes without saying that the elements constituting the embodiments in the above-described embodiments are not necessarily essential, except in cases where they are specifically stated as essential or where they are clearly considered essential in principle.

[0202] The present embodiment configured as described above may be subject to the following claims: That is, in the centrifugal blower, the electric motor is disposed radially inward of the impeller cylinder within the opening, is supported by the impeller cylinder, and includes a rotor that applies a rotational force to the impeller cylinder.

[0203] The rotor is formed in a cylindrical shape centered on the axis and has a cylindrical portion and a hollow portion of the cylindrical portion that is formed to cover one side in the fan axial direction. The rotor is formed to move toward the other side in the fan axial direction as it moves from the inside to the outside in the radial direction, and has a lid portion that guides air drawn into the intake port to the air flow path. [Explanation of symbols]

[0204] 10 Centrifugal blower 14 Electric motor 60 wings 62 Shroud 62a Air intake 62b Coverage Area 64 Main plate 66 Impeller cup 68 Air Flow Path 67 Slope 94 Integrated composition

Claims

1. A centrifugal blower, A plurality of blades (60) arranged in a circumferential direction (Edr) around an axis line (Sa); a shroud (62) that is formed so as to cover the plurality of blades from one side in the axial direction when the direction in which the axis extends is defined as an axial direction (DRa), is provided in a ring shape centered on the axis, and forms an intake port (62a) that opens in the axial direction on the radially inner side centered on the axis; a main plate (64) formed so as to cover the plurality of blades from the other side in the axial direction, provided in a ring shape centered on the axis, and further forming an opening (64a) opening in the axial direction on the inner side in the radial direction; a tubular portion (66) that is disposed within the opening, is formed in a cylindrical shape centered on the axis line, and is configured to be rotatable about the axis line by a rotational force of an electric motor (14); The plurality of blades, the shroud, and the cylindrical portion constitute an integrated structure (94), an air flow passage (68) is provided between the cylindrical portion and the main plate and the shroud, and between two adjacent blades of the plurality of blades; The cylindrical portion is connected to the main plate so as to be unable to move relative to the main plate, When the plurality of blades, the shroud, the cylindrical portion, and the main plate rotate toward one side (DRf) in the circumferential direction by the rotational force of the electric motor, air sucked into the intake port from one side in the axial direction is blown outward in the radial direction through the air flow path, A cover region (62b) is provided on the other side of the shroud in the axial direction so as to cover the one side of the cylindrical portion in the axial direction, and the cover region is formed in an arc shape that is convex toward the other side of the axial direction in a cross-sectional view of the shroud cut along a plane including the axis, The shroud is formed to progress toward one side in the axial direction from a radially outer end (62d) of the cover region toward a radially inner end (621) of the shroud, An end surface (67) is provided at one end of the cylindrical portion in the axial direction, A centrifugal blower in which, when a line perpendicular to the axial direction and perpendicular to the radial direction is defined as a first virtual line (230), and a tangent line perpendicular to the first virtual line and tangent to the cover area is defined as a second virtual line (162b), the cover area and the end face are formed such that the end face of the cylindrical portion and the second virtual line are parallel to each other, or the axial distance (ZL) between the end face and the second virtual line increases from the inside to the outside in the radial direction.

2. 2. The centrifugal blower according to claim 1, wherein the end surface (67) of the cylindrical portion is an inclined surface that progresses toward one side in the axial direction as it moves from the outer side in the radial direction to the inner side in the radial direction.

3. 3. The centrifugal blower according to claim 2, wherein the main plate has a main plate flow path surface (170) that is disposed on one side in the axial direction with respect to the radially outer end portion (67a) of the inclined surface and that is formed along the circumferential direction.

4. 4. The centrifugal blower according to claim 3, wherein the main plate includes an inner peripheral inclined surface (171) that is disposed between the main plate flow path surface and the inclined surface of the cylindrical portion, that is formed over the circumferential direction, and that progresses toward one side in the axial direction as it moves from the inside to the outside in the radial direction (DRr).

5. Among the plurality of blades, two adjacent blades that are disposed on the other side of the circumferential direction include a positive pressure surface (160a) that is formed on one side of the circumferential direction (Edr) and on which a positive pressure acts during the rotation on the one side of the circumferential direction, The blade disposed on one side in the circumferential direction of the two adjacent blades includes a negative pressure surface (160b) formed on the other side in the circumferential direction and on which a negative pressure acts during the rotation on the one side in the circumferential direction, The narrow angle formed between a virtual plane (210) perpendicular to the axial direction (DRa) and the inclined surface is defined as an impeller inclination angle (θ); When the area of ​​a cross section of the region (220) between the shroud and the cylindrical portion of the air flow path cut by a plane including the axis is defined as a flow path cross-sectional area, 5. The centrifugal blower according to claim 2, wherein the impeller inclination angle gradually increases as the impeller moves from the positive pressure surface side toward the negative pressure surface side toward one side in the circumferential direction, so that the flow path cross-sectional area gradually decreases as the impeller moves from the positive pressure surface side toward the negative pressure surface side toward one side in the circumferential direction.

6. The positive pressure surface side of the inclined surface is disposed on the other side in the axial direction of the inner end portion (67b) of the inclined surface in the radial direction compared to the negative pressure surface side of the inclined surface, 6. The centrifugal blower according to claim 5, wherein the radially inner end portion of the inclined surface is formed so as to gradually progress toward one side in the axial direction as it progresses toward one side in the circumferential direction from the positive pressure surface side toward the negative pressure surface side.

7. Among the plurality of blades, two adjacent blades that are disposed on the other side of the circumferential direction include a positive pressure surface (160a) that is formed on one side of the circumferential direction (Edr) and on which a positive pressure acts during the rotation on the one side of the circumferential direction, The blade disposed on one side in the circumferential direction of the two adjacent blades includes a negative pressure surface (160b) formed on the other side in the circumferential direction and on which a negative pressure acts during the rotation on the one side in the circumferential direction, The positive pressure surface and the negative pressure surface are arranged to overlap with the inner peripheral inclined surface (171) of the main plate in the axial direction, The narrow angle formed between a virtual plane (240) perpendicular to the axial direction and the inner peripheral inclined surface is defined as a main plate inclination angle (θa), When the area of ​​a cross section obtained by cutting the region (174) between the shroud and the main plate in the air flow passage by a plane including the axis is defined as a flow passage cross-sectional area, 5. The centrifugal blower according to claim 4, wherein the main plate inclination angle gradually increases as the flow path moves from the positive pressure surface toward the negative pressure surface toward one side in the circumferential direction, so that the flow path cross-sectional area gradually decreases as the flow path moves from the positive pressure surface toward the negative pressure surface toward one side in the circumferential direction.

8. Among the plurality of blades, two adjacent blades that are disposed on the other side of the circumferential direction include a positive pressure surface (160a) that is formed on one side of the circumferential direction (Edr) and on which a positive pressure acts during the rotation on the one side of the circumferential direction, The blade disposed on one side in the circumferential direction of the two adjacent blades includes a negative pressure surface (160b) formed on the other side in the circumferential direction and on which a negative pressure acts during the rotation on the one side in the circumferential direction, The positive pressure surface and the negative pressure surface are arranged to overlap with the main plate flow passage surface of the main plate in the axial direction, When the area of ​​a cross section of a region (175) between the shroud and the main plate flow passage surface (170) of the air flow passage is cut by a plane including the axis, the flow passage cross-sectional area is:

5. The centrifugal blower according to claim 4, wherein the main plate flow path surface is formed so as to gradually progress to one side in the axial direction as it progresses from the positive pressure surface toward the negative pressure surface to one side in the circumferential direction, so that the flow path cross-sectional area gradually becomes smaller as it progresses from the positive pressure surface toward the negative pressure surface to one side in the circumferential direction.

9. The radially outer side of the cylindrical portion forms a stepped shape having two outer peripheral surfaces (190, 191) that are arranged to be shifted in the radial direction and are formed along the axial direction, The radially inner side of the main plate forms a stepped shape having two inner circumferential surfaces (180, 181) that are arranged to be shifted in the radial direction and are formed along the axial direction, 9. The centrifugal blower according to claim 2, wherein, when the radial outer side of the tubular portion and the radial inner side of the main plate are fitted together, the two or more outer peripheral surfaces face corresponding inner peripheral surfaces of the two or more inner peripheral surfaces via gaps (200, 201), thereby forming a labyrinth structure that prevents air from flowing between the radial outer side of the tubular portion and the radial inner side of the main plate.

10. The radially outer side of the cylindrical portion is disposed between the two outer circumferential surfaces and includes a first radial surface (192) formed along the radial direction, The radially inner side of the main plate is disposed between the two inner circumferential surfaces and includes a second radial surface (182) formed along the radial direction, 10. The centrifugal blower according to claim 9, wherein when the gap is defined as a first gap, the first radial surface and the second radial surface face each other via a second gap (202), thereby forming the labyrinth structure.

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