WO2020136788A1

WO2020136788A1 - Centrifugal blower, blower device, air conditioner, and refrigeration cycle device

Info

Publication number: WO2020136788A1
Application number: PCT/JP2018/048063
Authority: WO
Inventors: 拓矢寺本; 弘恭林; 一也道上; 亮堀江; 貴宏山谷; 堤　博司
Original assignee: 三菱電機株式会社
Priority date: 2018-12-27
Filing date: 2018-12-27
Publication date: 2020-07-02
Also published as: CN113195903A; EP3904696A1; ES2945787T3; CN113195903B; JP7130061B2; EP3904696A4; JPWO2020136788A1; EP3904696B1

Abstract

This centrifugal blower comprises an impeller having a disc-shaped main plate and a blade, and a fan casing having a bell mouth, wherein the bell mouth has an air intake part that forms an inlet port and is formed such that an opening diameter gradually decreases from an upstream end portion to a downstream end portion in the direction of an airflow suctioned into the fan casing, a virtual ellipse is defined in which in a vertical cross-section of the bell mouth, one end portion among the upstream end portion and the downstream end portion is set as an end portion of a long axis, the other end portion thereamong is set as an end portion of a short axis, and an intersection between the long axis and the short axis is located on an outer peripheral side from the downstream end portion with respect to a rotation axis of the impeller, and when an outline of the shortest distance connecting the upstream end portion and the downstream end portion is defined as a first outline in an elliptic outline, within a range in which the air intake part is surrounded by a first virtual tangent line in contact with the upstream end portion of the ellipse, a second virtual tangent line in contact with the downstream end portion of the ellipse, and the first outline, a wall part between the upstream end portion and the downstream end portion becomes swollen in a direction away from the first outline with the intersection as a reference.

Description

Centrifugal blower, blower, air conditioner and refrigeration cycle device

The present invention relates to a centrifugal blower having a casing equipped with a bell mouth, a blower equipped with the same, an air conditioner, and a refrigeration cycle apparatus.

Conventionally, in a bell blower of a centrifugal blower, a curved surface formed by a wall that shrinks from the outer peripheral side to the inner peripheral direction and a wall that is located on the downstream side of intake air with respect to the curved surface and expands from the inner peripheral side to the outer peripheral direction. Has been proposed (see, for example, Patent Document 1). Here, in the centrifugal blower, the curvature radius of the curved surface in the contraction direction from the outer peripheral side to the inner peripheral direction is defined as the curvature radius Y, and the curvature radius of the curved surface in the expansion direction from the inner peripheral side to the outer peripheral direction is defined as the curvature radius Z. Define. In this case, in the centrifugal blower of Patent Document 1, since the shape of the bell mouth has a relationship of the curvature radius Y>the curvature radius Z, the flow of the airflow becomes smooth at the suction port, and the effect of improving noise can be obtained.

U.S. Patent Application Publication No. 2006/0034686

However, in the case where the bell mouth is expanded in the radial direction or the axial direction of the rotating shaft for further improvement in characteristics, the radius of curvature of the curved surface of the bell mouth becomes small, so that the air flow is easily separated from the bell mouth and noise May worsen.

The present invention is for solving the above problems, and even if the bell mouth is inflated in the radial direction or the axial direction of the rotating shaft, a centrifugal blower for reducing noise, and the same are provided. And an air conditioner and a refrigeration cycle apparatus.

A centrifugal blower according to the present invention stores an impeller having a disk-shaped main plate and a plurality of blades installed at a peripheral portion of the main plate, an impeller, and rectifies gas sucked into the impeller. A fan casing having a bell mouth, wherein the bell mouth forms a suction port through which a gas flowing into the fan casing passes, and the bell mouth is directed from an upstream end to a downstream end in a direction of an air flow sucked into the fan casing. It has an air intake part formed so that the opening diameter becomes gradually smaller, and in the vertical section of the bell mouth, one end of the upstream end and the downstream end is the end of the long axis, and the other end. The end is defined as the end of the short axis, and the intersection of the long axis and the short axis defines a virtual ellipse located on the outer peripheral side with respect to the rotation axis of the impeller than the downstream end. If the outermost line connecting the upstream end portion and the downstream end portion is defined as the first outer shape line, the air intake portion has an imaginary first tangent line that contacts the upstream end portion of the ellipse and the downstream end portion of the ellipse. Within the range surrounded by the imaginary second tangent line that contacts the portion and the first outline, the wall portion between the upstream end portion and the downstream end portion swells in the direction away from the first outline line based on the intersection point. It is something that is going out.

In the centrifugal blower according to the present invention, the air intake portion is surrounded by a virtual first tangent line that contacts the upstream end of the ellipse, a virtual second tangent line that contacts the downstream end of the ellipse, and a first contour line. Within the range, the wall portion between the upstream end portion and the downstream end portion swells in the direction away from the first outline with the intersection as the reference. Since the centrifugal blower is provided with the configuration, the curvature of the bell mouth near the downstream end, which is the innermost diameter of the bell mouth, approaches the axial direction of the rotating shaft. Therefore, the centrifugal blower can cause the fast airflow flowing into the bell mouth to extend from the outer peripheral side to the inner peripheral side of the bell mouth, and can smoothly turn the gas flow in the axial direction in the air intake portion. As a result, the centrifugal blower can suppress the separation of the airflow in the vicinity of the downstream end that is the innermost diameter in the bell mouth, and can suppress the inflow of the turbulent airflow into the impeller, thereby suppressing noise. You can

It is a perspective view of the centrifugal fan concerning Embodiment 1 of the present invention. It is the side view which looked at the centrifugal fan of FIG. 1 from the suction inlet side. FIG. 3 is a partial cross-sectional view of the centrifugal blower of FIG. 2 taken along the line AA. It is an enlarged view of the B section of the bell mouth of FIG. FIG. 6 is a partially enlarged view of a bell mouth of the centrifugal blower according to Embodiment 2 of the present invention. It is a partially expanded view of a bell mouth of a centrifugal blower according to Embodiment 3 of the present invention. It is a partially expanded view of a bell mouth of a centrifugal blower according to Embodiment 4 of the present invention. It is a partially expanded view of a bell mouth of a centrifugal blower according to Embodiment 5 of the present invention. It is the elements on larger scale of the bell mouth of the centrifugal fan concerning Embodiment 6 of the present invention. It is a partially expanded view of a bell mouth of a centrifugal blower according to Embodiment 7 of the present invention. It is the elements on larger scale of the bell mouth of the centrifugal fan concerning Embodiment 8 of the present invention. It is a side view of the centrifugal air blower concerning Embodiment 9 of the present invention. FIG. 13 is a sectional view of the centrifugal blower of FIG. 12 taken along the line BB. It is CC sectional view taken on the line of the centrifugal blower of FIG. It is a figure which shows the structure of the air blower concerning Embodiment 10 of this invention. It is a perspective view of the air conditioning apparatus which concerns on Embodiment 11 of this invention. It is a figure which shows the internal structure of the air conditioning apparatus which concerns on Embodiment 11 of this invention. It is sectional drawing of the air conditioning apparatus which concerns on Embodiment 11 of this invention. It is another sectional view of the air harmony device concerning Embodiment 11 of the present invention. It is a figure which shows the structure of the refrigerating-cycle apparatus which concerns on Embodiment 12 of this invention.

Hereinafter, the centrifugal blower 1 to the centrifugal blower 1H, the blower 30, the air conditioner 40, and the refrigeration cycle device 50 according to the embodiment of the present invention will be described with reference to the drawings. In the following drawings including FIG. 1, the relative dimensional relationship and shape of each component may be different from the actual one. In addition, in the following drawings, the components denoted by the same reference numerals are the same or equivalent, and this is common to all the texts of the specification. In addition, to facilitate understanding, terms indicating directions (for example, “up”, “down”, “right”, “left”, “front”, “rear”, etc.) are used as appropriate, but these notations are For convenience of description, such description is merely provided, and the arrangement and orientation of the device or parts are not limited.

Embodiment 1.
[Centrifugal blower 1]
1 is a perspective view of a centrifugal blower 1 according to Embodiment 1 of the present invention. FIG. 2 is a side view of the centrifugal blower 1 of FIG. 1 viewed from the suction port 5 side. FIG. 3 is a partial cross-sectional view of the centrifugal blower 1 of FIG. 2 taken along the line AA. The arrows shown in FIG. 3 indicate the flow of air flowing through the centrifugal blower 1. The basic structure of the centrifugal blower 1 will be described with reference to FIGS. 1 to 3. The centrifugal blower 1 is, for example, a multi-blade centrifugal type centrifugal blower 1 such as a sirocco fan or a turbo fan, and includes an impeller 2 that generates an air flow and a fan casing 4 that houses the impeller 2.

(Impeller 2)
The impeller 2 is rotationally driven by a motor or the like (not shown), and the centrifugal force generated by the rotation forcedly sends air outward in the radial direction. As shown in FIG. 1, the impeller 2 has a disc-shaped main plate 2a and a plurality of blades 2d installed on a peripheral edge 2a1 of the main plate 2a. A shaft portion 2b is provided at the center of the main plate 2a. A fan motor (not shown) is connected to the center of the shaft portion 2b, and the impeller 2 is rotated by the driving force of the motor.

Further, in the impeller 2, as shown in FIG. 3, in the axial direction of the rotation axis RS of the shaft portion 2b, a ring-shaped side plate 2c facing the main plate 2a is provided at an end of the plurality of blades 2d opposite to the main plate 2a. have. By connecting the plurality of blades 2d, the side plate 2c maintains the positional relationship of the tips of the blades 2d and reinforces the plurality of blades 2d. The impeller 2 may have a structure without the side plate 2c. When the impeller 2 has the side plate 2c, one end of each of the plurality of blades 2d is connected to the main plate 2a and the other end is connected to the side plate 2c. Therefore, the plurality of blades 2d are arranged between the main plate 2a and the side plate 2c. The impeller 2 is formed into a cylindrical shape by a main plate 2a and a plurality of blades 2d, and a suction port 2e of the impeller 2 is provided on the side plate 2c side opposite to the main plate 2a in the axial direction of the rotation axis RS of the shaft portion 2b. Is formed.

The plurality of blades 2d are arranged in a circle around the shaft 2b, and the base ends are fixed on the surface of the main plate 2a. The plurality of blades 2d are provided on both sides of the main plate 2a in the axial direction of the rotation axis RS of the shaft portion 2b. The blades 2d are arranged on the peripheral edge portion 2a1 of the main plate 2a at regular intervals. Each blade 2d is formed in a curved rectangular plate shape, for example, and is installed along the radial direction or inclined at a predetermined angle with respect to the radial direction.

The impeller 2 has the above-described configuration, and when it is rotated, the air sucked into the space surrounded by the main plate 2a and the plurality of blades 2d is passed between the blade 2d and the adjacent blade 2d, As shown in FIG. 3, it can be fed outward in the radial direction. In the first embodiment, each blade 2d is provided so as to rise substantially perpendicularly to the main plate 2a, but the present invention is not limited to this configuration, and each blade 2d is perpendicular to the main plate 2a. And may be inclined.

(Fan casing 4)
The fan casing 4 surrounds the impeller 2 and rectifies the air blown from the impeller 2. The fan casing 4 has a scroll portion 41 and a discharge portion 42.

(Scroll part 41)
The scroll portion 41 forms an air passage that converts the dynamic pressure of the airflow generated by the impeller 2 into static pressure. The scroll portion 41 covers the impeller 2 from the axial direction of the rotation axis RS of the shaft portion 2b forming the impeller 2, and the side wall 4a having the suction port 5 for taking in air, and the impeller 2 of the shaft portion 2b. And a peripheral wall 4c that surrounds the rotation axis RS in the radial direction. Further, the scroll portion 41 is positioned between the discharge portion 42 and the winding start portion 41a of the peripheral wall 4c to form a curved surface, and the airflow generated by the impeller 2 is discharged to the discharge port 42a via the scroll portion 41. It has a tongue 43 to guide it. The radial direction of the shaft portion 2b is a direction perpendicular to the shaft portion 2b. The inner space of the scroll portion 41 configured by the peripheral wall 4c and the side wall 4a is a space in which the air blown out from the impeller 2 flows along the peripheral wall 4c.

(Side wall 4a)
The side wall 4 a is arranged perpendicular to the axial direction of the rotation axis RS of the impeller 2 and covers the impeller 2. A suction port 5 is formed in the side wall 4 a of the fan casing 4 so that air can flow between the impeller 2 and the outside of the fan casing 4. The suction port 5 is formed in a circular shape, and is arranged so that the center of the suction port 5 and the center of the shaft portion 2b of the impeller 2 substantially coincide with each other. Due to the configuration of the side wall 4a, the air in the vicinity of the suction port 5 flows smoothly and efficiently flows into the impeller 2 from the suction port 5. As shown in FIGS. 1 to 3, the centrifugal blower 1 is a double-suction type fan casing having side walls 4a having suction ports 5 formed on both sides of a main plate 2a in the axial direction of a rotation axis RS of a shaft portion 2b. Have 4. That is, in the centrifugal blower 1, the fan casing 4 has two side walls 4a, and the side walls 4a are arranged to face each other.

(Peripheral wall 4c)
The peripheral wall 4c surrounds the impeller 2 in the radial direction of the shaft portion 2b and constitutes an inner peripheral surface facing the plurality of blades 2d. The peripheral wall 4c is arranged parallel to the axial direction of the rotation axis RS of the impeller 2 and covers the impeller 2. As shown in FIG. 2, the peripheral wall 4c has a discharge portion 42 on the side away from the tongue portion 43 along the rotation direction R of the impeller 2 from the winding start portion 41a located at the boundary between the tongue portion 43 and the scroll portion 41. Is provided up to the winding end portion 41b located at the boundary between the scroll portion 41 and the scroll portion 41. The winding start portion 41a is an end portion on the upstream side of the air flow generated by the rotation of the impeller 2 in the peripheral wall 4c forming the curved surface, and the winding end portion 41b is the downstream end of the air flow generated by the rotation of the impeller 2. Side end.

The peripheral wall 4c has a width in the axial direction of the rotation axis RS of the impeller 2. As shown in FIG. 2, the peripheral wall 4c is formed in a spiral shape defined by a predetermined enlargement ratio in which the distance from the rotation axis RS formed by the shaft portion 2b gradually increases in the rotation direction R of the impeller 2. To be done. That is, in the peripheral wall 4c, the gap between the peripheral wall 4c and the outer circumference of the impeller 2 is enlarged at a predetermined ratio from the tongue portion 43 to the discharge portion 42, and the flow passage area of air is gradually increased. The spiral shape defined by the predetermined enlargement ratio includes, for example, a logarithmic spiral, an Archimedes spiral, or a spiral shape based on an involute curve or the like. The inner peripheral surface of the peripheral wall 4c forms a curved surface that smoothly curves along the circumferential direction of the impeller 2 from a winding start portion 41a that is a spiral start to a winding end portion 41b that is a spiral end. .. With such a configuration, the air sent from the impeller 2 smoothly flows in the gap between the impeller 2 and the peripheral wall 4c toward the discharge portion 42. Therefore, in the fan casing 4, the static pressure of air efficiently increases from the tongue portion 43 toward the discharge portion 42.

(Discharge part 42)
The discharge part 42 forms a discharge port 42a through which the airflow generated by the impeller 2 and passed through the scroll part 41 is discharged. The discharge part 42 is configured by a hollow tube having a rectangular cross section orthogonal to the flow direction of the air flowing along the peripheral wall 4c. As shown in FIGS. 1 and 2, the discharge part 42 guides the air sent out from the impeller 2 and flowing in the gap between the peripheral wall 4 c and the impeller 2 to the outside of the fan casing 4. Forming a path.

As shown in FIG. 1, the discharge part 42 includes an extension plate 42b, a diffuser plate 42c, a first side plate 42d, a second side plate 42e, and the like. The extending plate 42b is smoothly continuous with the winding end portion 41b on the downstream side of the peripheral wall 4c and is integrally formed with the peripheral wall 4c. The diffuser plate 42c is integrally formed with the tongue portion 43 of the fan casing 4, and faces the extension plate 42b. The diffuser plate 42c is formed at a predetermined angle with the extending plate 42b so that the cross-sectional area of the flow path gradually increases along the air flow direction in the discharge part 42. The first side plate 42d is formed integrally with the side wall 4a of the fan casing 4, and the second side plate 42e is formed integrally with the side wall 4a on the opposite side of the fan casing 4. And the 1st side plate 42d and the 2nd side plate 42e which oppose are formed between the extended plate 42b and the diffuser plate 42c. As described above, in the discharge unit 42, the extension plate 42b, the diffuser plate 42c, the first side plate 42d, and the second side plate 42e form a flow channel having a rectangular cross section.

(Tongue 43)
In the fan casing 4, a tongue portion 43 is formed between the diffuser plate 42c of the discharge portion 42 and the winding start portion 41a of the peripheral wall 4c. The tongue portion 43 is a convex portion that is provided at the boundary between the scroll portion 41 and the discharge portion 42 and bulges inside the fan casing 4. The tongue portion 43 extends in the fan casing 4 in a direction parallel to the axial direction of the rotation axis RS of the shaft portion 2b. The tongue portion 43 guides the airflow generated by the impeller 2 to the discharge port 42a via the scroll portion 41.

The tongue portion 43 is formed with a predetermined radius of curvature, and the peripheral wall 4c is smoothly connected to the diffuser plate 42c via the tongue portion 43. When the air sent out from the suction port 5 through the impeller 2 is collected by the fan casing 4 and flows into the discharge part 42, the tongue part 43 becomes a branch point of the air flow path. That is, at the inflow port of the ejection part 42, an air flow toward the ejection port 42a and an air flow re-inflowing from the tongue part 43 to the upstream side are formed. Further, the static pressure of the air flow flowing into the discharge portion 42 rises while passing through the fan casing 4, and becomes higher than that in the fan casing 4. Therefore, the tongue portion 43 has a function of partitioning such a pressure difference, and also has a function of guiding the air flowing into the discharge portion 42 to each flow path by the curved surface.

(Bellmouth 3)
The suction port 5 provided on the side wall 4 a is formed by the bell mouth 3. The bell mouth 3 rectifies the gas sucked into the impeller 2 and causes the gas to flow into the suction port 2e of the impeller 2. The bell mouth 3 is formed such that the opening diameter gradually decreases from the outside to the inside of the fan casing 4. The bell mouth 3 is installed upstream of the impeller 2 in the flow direction of the gas sucked into the fan casing 4. The bell mouth 3 is formed at a position facing the suction port 2e of the impeller 2. The bell mouth 3 has an air intake portion 3c that guides the air flow sucked into the fan casing 4 into the fan casing 4.

The air intake part 3c is formed in a tubular shape, and the inner peripheral surface of the air intake part 3c forms the suction port 5. The gas flowing from the outside to the inside of the fan casing 4 passes through the suction port 5. The air intake portion 3c has an opening diameter from the upstream end portion 3a, which is the upstream end portion in the direction of the air flow sucked into the fan casing 4 through the suction port 5, to the downstream end portion 3b, which is the downstream end portion. It is formed to be gradually smaller. That is, the air intake portion 3c is provided so as to extend in the axial direction of the rotation shaft RS, and the air passage is narrowed from the upstream side to the downstream side of the air flow sucked into the fan casing 4 through the suction port 5. Has been formed.

The bell mouth 3 is formed in an annular shape in a plan view as viewed in the axial direction of the rotation axis RS, the upstream end portion 3a forms an outer edge portion, and the downstream end portion 3b forms an inner edge portion. Therefore, the upstream end 3a is the outermost diameter portion of the bell mouth 3, and is the most enlarged portion of the bell mouth 3 formed in a tubular shape. The downstream end portion 3b is the innermost portion of the bell mouth 3, and is the most contracted portion of the bell mouth 3 formed in a tubular shape.

The air intake portion 3c has a circular cross section in a rotation surface centered on the axial direction of the rotation axis RS, and a surface forming the suction port 5 is formed into a curved surface. Therefore, in the air intake part 3c, as shown in FIG. 3, in the vertical cross section of the bell mouth 3, the wall part 3c1 forming the suction port 5 is formed in an arc shape.

FIG. 4 is an enlarged view of part B of the bell mouth 3 of FIG. Next, as shown in FIG. 4, a detailed configuration of the bell mouth 3 will be described with reference to a sectional view of the bell mouth 3. The rotation axis RS is described to explain the positional relationship between the rotation axis RS, the downstream end portion 3b, and the intersection EC. In FIG. 4, an ellipse EL is an imaginary line in which the upstream end 3a of the bell mouth 3 is the first end E1 of the short axis MI and the downstream end 3b of the bell mouth 3 is the second end E2 of the long axis MA. It is an ellipse. The virtual ellipse EL has a short axis MI extending from the upstream end 3a into the fan casing 4 and a long axis MA extending from the downstream end 3b in a direction parallel to the radial direction of the impeller 2 in the vertical cross section of the bell mouth 3. Have and. The intersection EC is the intersection of the short axis MI and the long axis MA, and is the center point of the virtual ellipse EL.

The upstream end 3a is the outermost diameter portion of the bell mouth 3 in the radial direction, and the downstream end 3b is the innermost diameter portion of the bell mouth 3. In the vertical cross section of the bell mouth 3, the virtual ellipse EL has one end of the upstream end 3a and the downstream end 3b as the end of the major axis MA and the other end as the end of the minor axis MI. The intersection EC of the long axis MA and the short axis MI is located on the outer peripheral side with respect to the rotation axis RS of the impeller 2 with respect to the downstream end portion 3b.

As shown in FIG. 4, the first outline L1 is the outline of the shortest distance connecting the upstream end 3a and the downstream end 3b in the outline of the ellipse EL.

The first tangent line HT is a virtual tangent line that contacts the first end E1 of the ellipse EL, and the second tangent line VT is a virtual tangent line that contacts the second end E2 of the ellipse EL. That is, the first tangent line HT is a virtual tangent line that contacts the upstream end 3a of the ellipse EL, and the second tangent line VT is a virtual tangent line that contacts the downstream end 3b of the ellipse EL.

The curved surface ES is a virtual surface created by the locus of the first outline L1 when the ellipse EL is rotated about the rotation axis RS. The arrow F1 is an arrow indicating the direction in which the gas flows when the air intake portion 3c of the bell mouth 3 has the shape of the curved surface ES. The arrow F2 is an arrow indicating the direction in which the gas flows along the air intake portion 3c of the bell mouth 3 in the centrifugal blower 1 of the first embodiment.

In the bell mouth 3, the wall portion 3c1 of the air intake portion 3c has the upstream end portion 3a as the first end portion E1 of the short axis MI and the downstream end portion 3b between the upstream end portion 3a and the downstream end portion 3b. It bulges toward the inner peripheral side of the bell mouth 3 from the first outer shape line L1 of the virtual ellipse EL which is the second end E2 of the major axis MA. In other words, in the air intake part 3c, the wall part 3c1 between the upstream end part 3a and the downstream end part 3b swells in the direction away from the first outline L1 with the intersection EC as a reference. Therefore, as shown in FIG. 4, the air intake portion 3c is formed in a curved shape that draws an arc in the vertical cross section of the bell mouth 3.

The air intake portion 3c includes a virtual first tangent line HT that contacts the first end E1 of the ellipse EL, a virtual second tangent line VT that contacts the second end E2 of the ellipse EL, and a first outline L1. It swells within the enclosed area.

That is, the air intake part 3c is composed of a virtual first tangent line HT that contacts the upstream end 3a of the ellipse EL, a virtual second tangent line VT that contacts the downstream end 3b of the ellipse EL, and a first outline L1. Within the enclosed range, the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in the direction away from the first outline L1 with the intersection EC as a reference. The bell mouth 3 of the centrifugal blower 1 expands a general bell mouth in the radial direction and the axial direction. The centrifugal blower 1 has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in the direction away from the first outline L1 on the basis of the intersection EC, so that the downstream end portion having the innermost diameter is formed. The curvature of the bell mouth 3 near 3b approaches the axial direction.

[Operation of centrifugal blower 1]
When the impeller 2 rotates, the air outside the fan casing 4 is sucked into the fan casing 4 through the suction port 5. The air sucked into the fan casing 4 flows along the air intake portion 3c of the bell mouth 3 and is sucked into the impeller 2. The air sucked into the impeller 2 becomes an airflow to which dynamic pressure and static pressure are applied in the process of passing between the plurality of blades 2d, and is blown out toward the radially outer side of the impeller 2. The dynamic pressure of the air flow blown out from the impeller 2 is converted into static pressure while being guided between the inside of the peripheral wall 4c and the blade 2d in the scroll portion 41. Then, the airflow blown out from the impeller 2 passes through the scroll portion 41, and then is blown out of the fan casing 4 from the discharge port 42a formed in the discharge portion 42.

[Effect of centrifugal blower 1]
The air intake part 3c is surrounded by an imaginary first tangent line HT that contacts the upstream end 3a of the ellipse EL, an imaginary second tangent line VT that contacts the downstream end 3b of the ellipse EL, and a first outline L1. Within the range, the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b swells in the direction away from the first outline L1 with the intersection EC as a reference. With the configuration of the centrifugal blower 1, the curvature of the bell mouth 3 near the downstream end 3b, which is the innermost diameter of the bell mouth 3, approaches the axial direction of the rotation axis RS. Therefore, the centrifugal blower 1 can cause the fast airflow flowing into the bell mouth 3 to extend from the outer peripheral side to the inner peripheral side of the bell mouth 3, and can easily turn the gas flow in the axial direction in the air intake portion 3c. .. As a result, the centrifugal blower 1 can suppress the separation of the air flow in the vicinity of the downstream end portion 3b, which is the innermost diameter, in the bell mouth 3, and can suppress the inflow of the turbulent air flow into the impeller 2, thereby reducing noise. Can be suppressed. Further, the bell mouth 3 suppresses the separation of the air flow in the vicinity of the downstream end portion 3b that is the innermost diameter, and can suppress the inflow of the turbulent air flow into the impeller 2, so that the centrifugal blower 1 efficiently takes in the air. be able to. If the centrifugal blower 1 according to the first embodiment is not applied, that is, if the general bell mouth is expanded in the radial direction and the axial direction of the rotation axis, the shape of the bell mouth is along the ellipse EL. The air flow may separate from the bell mouth on the inner peripheral side. The bell mouth 3 of the centrifugal blower 1 according to the first embodiment has the above-described configuration, so that air flow separation near the downstream end 3b, which is the innermost diameter, can be reduced.

Embodiment 2.
FIG. 5 is a partially enlarged view of bell mouth 3A of centrifugal fan 1A according to the second embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 of FIGS. 1 to 4 are designated by the same reference numerals, and the description thereof will be omitted. The centrifugal blower 1A according to the second embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3A are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3A of the centrifugal blower 1A according to the second embodiment will be mainly described with reference to FIG.

The distance between the upstream end 3a and the downstream end 3b of the bell mouth 3A in the axial direction of the rotation axis RS is defined as the first axial direction distance D1. In other words, the first axial distance D1 is the rotation axis RS when the upstream end 3a and the downstream end 3b of the bell mouth 3A are projected onto the rotation axis RS in the direction perpendicular to the rotation axis RS. It is the distance between the upstream end 3a and the downstream end 3b at the projected position. The first axial distance D1 is also the minor axis MI radius of the virtual ellipse EL. That is, the first axial direction distance D1 is also the distance between the upstream end 3a and the intersection EC of the virtual ellipse EL. Further, a distance between the upstream end 3a and the downstream end 3b of the bell mouth 3A in the radial direction of the rotation axis RS is defined as a first radial distance D2. In other words, the first radial distance D2 is the distance between the upstream end portion 3a and the downstream end portion 3b of the bell mouth 3A that appear on the same virtual plane in a plan view seen in the axial direction of the rotation axis RS. Is. The first radial direction distance D2 is the major axis radius of the virtual ellipse EL. That is, the first radial distance D2 is also the distance between the downstream end 3b and the intersection EC of the virtual ellipse EL.

The bell mouth 3A is formed so as to satisfy the relationship of the first radial direction distance D2>the first axial direction distance D1. In the bell mouth 3A, a portion satisfying the relationship of the first radial direction distance D2>the first axial direction distance D1 may be formed on the entire circumference of the bell mouth 3 or may be formed partially in the circumferential direction. May be. The bell mouth 3A of the centrifugal blower 1A expands a general bell mouth in the radial direction. The centrifugal blower 1A has a wall end 3c1 between the upstream end 3a and the downstream end 3b, which has a shape bulging in a direction away from the first outline L1 on the basis of the intersection EC, so that the downstream end having the innermost diameter is formed. The curvature of the bell mouth 3A near 3b approaches the axial direction.

[Effect of centrifugal blower 1A]
As described above, the bell mouth 3A is formed so as to satisfy the relationship of the first radial direction distance D2>the first axial direction distance D1. The centrifugal blower 1A has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in a direction away from the first outline L1 with the intersection EC as a reference. Therefore, in the centrifugal blower 1A, the curvature of the bell mouth 3A near the downstream end 3b, which is the innermost diameter of the bell mouth 3A, approaches the axial direction of the rotation axis RS. Then, the centrifugal blower 1A can cause a fast airflow flowing into the bell mouth 3A to flow from the outer peripheral side to the inner peripheral side of the bell mouth 3A, and reasonably turn the gas flow in the air intake portion 3c in the axial direction. .. As a result, the centrifugal blower 1A can suppress the separation of the air flow in the vicinity of the downstream end 3b, which is the innermost diameter, in the bell mouth 3A, and can suppress the inflow of the disturbed air flow into the impeller 2, thereby reducing noise. Can be suppressed. Further, in the bell mouth 3A, the separation of the airflow in the vicinity of the downstream end portion 3b, which is the innermost diameter, is suppressed, and the turbulent airflow into the impeller 2 can be suppressed, so that the centrifugal blower 1A efficiently takes in air. be able to. If the centrifugal blower 1A according to the second embodiment is not applied, that is, if a general bell mouth is expanded in the radial direction, the shape is along the ellipse EL, the bell mouth is located inside the bell mouth. Airflow may separate. Since the bell mouth 3A of the centrifugal blower 1A has the above-mentioned configuration, it is possible to reduce air flow separation near the downstream end 3b, which is the innermost diameter.

Embodiment 3.
FIG. 6 is a partially enlarged view of bell mouth 3B of centrifugal fan 1B according to the third embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. 1 to 5 are given the same reference numerals and the description thereof will be omitted. The centrifugal blower 1B according to the third embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3B are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3B of the centrifugal blower 1B according to the third embodiment will be mainly described with reference to FIG.

In FIG. 6, the ellipse FL is an imaginary line in which the upstream end 3a of the bell mouth 3B is the first end G1 of the long axis MA2 and the downstream end 3b of the bell mouth 3B is the second end G2 of the short axis MI2. It is an ellipse. More specifically, the virtual ellipse FL is a direction parallel to the major axis MA2 extending from the upstream end 3a into the fan casing 4 and the direction parallel to the radial direction of the impeller 2 from the downstream end 3b in the vertical cross section of the bell mouth 3B. And a short axis MI2 extending to. The intersection EC is the intersection of the short axis MI2 and the long axis MA2, and is the center of the virtual ellipse FL.

In the vertical cross section of the bell mouth 3B, the virtual ellipse FL has one end of the upstream end 3a and the downstream end 3b as the end of the major axis MA2 and the other end as the end of the minor axis MI2. The intersection EC of the long axis MA2 and the short axis MI2 is located on the outer peripheral side with respect to the rotation axis RS of the impeller 2 with respect to the downstream end 3b.

As shown in FIG. 6, the first outline L1 is the outline of the shortest distance connecting the upstream end 3a and the downstream end 3b in the outline of the ellipse FL.

The first tangent line HT2 is a virtual tangent line that contacts the first end G1 of the ellipse FL, and the second tangent line VT2 is a virtual tangent line that contacts the second end G2 of the ellipse FL. That is, the first tangent line HT2 is a virtual tangent line that contacts the upstream end 3a of the ellipse FL, and the second tangent line VT2 is a virtual tangent line that contacts the downstream end 3b of the ellipse FL.

In the bell mouth 3B, the wall portion 3c1 of the air intake portion 3c has the upstream end portion 3a as the first end portion G1 of the long axis MA2 between the upstream end portion 3a and the downstream end portion 3b. It bulges toward the inner peripheral side of the bell mouth 3B from the first outer shape line L1 of the virtual ellipse FL which is the second end G2 of the short axis MI2. In other words, in the air intake part 3c, the wall part 3c1 between the upstream end part 3a and the downstream end part 3b swells in the direction away from the first outline L1 with the intersection EC as a reference. Therefore, as shown in FIG. 6, the air intake portion 3c is formed in a curved shape that draws an arc in the vertical cross section of the bell mouth 3B.

The air intake portion 3c includes a virtual first tangent line HT2 that contacts the first end portion G1 of the ellipse FL, a virtual second tangent line VT2 that contacts the second end portion G2 of the ellipse FL, and a first contour line L1. It swells within the enclosed area.

That is, the air intake portion 3c is composed of a virtual first tangent line HT2 contacting the upstream end portion 3a of the ellipse FL, a virtual second tangent line VT2 contacting the downstream end portion 3b of the ellipse FL, and the first contour line L1. Within the enclosed range, the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in the direction away from the first outline L1 with the intersection EC as a reference. The bell mouth 3B of the centrifugal blower 1B is a general bell mouth expanded in the axial direction. The centrifugal blower 1B has a wall end 3c1 between the upstream end 3a and the downstream end 3b, which has a shape that bulges in a direction away from the first outline L1 on the basis of the intersection EC, so that the downstream end having the innermost diameter is formed. The curvature of the bell mouth 3 near 3b approaches the axial direction.

As shown in FIG. 6, the distance between the upstream end 3a and the downstream end 3b of the bell mouth 3B in the axial direction of the rotation axis RS is defined as the second axial distance D3. In other words, when the upstream end portion 3a and the downstream end portion 3b of the bell mouth 3B are projected on the rotation axis RS in the direction perpendicular to the rotation axis RS, the second axial direction distance D3 is set on the rotation axis RS. It is the distance between the upstream end 3a and the downstream end 3b at the projected position. The second axial distance D3 is the major axis radius of the virtual ellipse FL. That is, the second axial distance D3 is also the distance between the upstream end 3a and the intersection EC of the virtual ellipse FL. In addition, a distance between the upstream end 3a and the downstream end 3b of the bell mouth 3B in the radial direction of the rotation axis RS is defined as a second radial distance D4. In other words, the second radial distance D4 is the distance between the upstream end portion 3a and the downstream end portion 3b of the bell mouth 3B that appear on the same virtual plane in a plan view seen in the axial direction of the rotation axis RS. Is. The second radial direction distance D4 is the minor axis radius of the virtual ellipse FL. That is, the second radial distance D4 is also the distance between the downstream end 3b and the intersection EC of the virtual ellipse FL.

The bell mouth 3B is formed so as to satisfy the relationship of the second radial distance D4<the second axial distance D3. In the bell mouth 3B, a portion satisfying the relationship of the second radial distance D4<the second axial distance D3 may be formed on the entire circumference of the bell mouth 3B or may be partially formed in the circumferential direction. May be. The bell mouth 3B of the centrifugal blower 1B is a general bell mouth expanded in the axial direction of the rotation axis RS. The centrifugal blower 1B has a wall end 3c1 between the upstream end 3a and the downstream end 3b, which has a shape that bulges in a direction away from the first outline L1 on the basis of the intersection EC, so that the downstream end having the innermost diameter is formed. The curvature of the bell mouth 3B near 3b approaches the axial direction.

[Effect of centrifugal blower 1B]
As described above, the bell mouth 3B is formed so as to satisfy the relationship of the second radial distance D4<the second axial distance D3. The centrifugal blower 1B has a shape in which the wall 3c1 between the upstream end 3a and the downstream end 3b bulges in the direction away from the first outline L1 on the basis of the intersection EC in the vertical cross section of the bell mouth 3B. .. Therefore, in the centrifugal blower 1B, the curvature of the bell mouth 3B near the downstream end 3b, which is the innermost diameter of the bell mouth 3B, approaches the axial direction of the rotation axis RS. Then, the centrifugal blower 1B can cause the fast airflow flowing into the bell mouth 3B to go along the inner circumference side from the outer circumference side of the bell mouth 3B, and can reasonably turn the gas flow in the air intake section 3c in the axial direction. .. As a result, the centrifugal blower 1B can suppress the separation of the airflow in the bell mouth 3B in the vicinity of the downstream end portion 3b, which is the innermost diameter, and can suppress the inflow of the disturbed airflow into the impeller 2, thereby reducing the noise. Can be suppressed. Further, the bell mouth 3B suppresses the separation of the air flow in the vicinity of the downstream end portion 3b, which is the innermost diameter, and can suppress the inflow of the turbulent air flow into the impeller 2, so that the centrifugal blower 1B efficiently takes in the air. be able to. If the centrifugal blower 1B according to the third embodiment is not applied, that is, if a general bell mouth is expanded in the axial direction of the rotation axis, the shape is along the ellipse FL, the inner circumference side of the bell mouth is The airflow may peel off from the bell mouth. The bell mouth 3B of the centrifugal blower 1B according to the third embodiment has the above-described configuration, so that air flow separation near the downstream end 3b, which is the innermost diameter, can be reduced.

Fourth Embodiment
FIG. 7 is a partially enlarged view of bell mouth 3C of centrifugal fan 1C according to the fourth embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. 1 to 6 are designated by the same reference numerals and the description thereof will be omitted. The centrifugal blower 1C according to the fourth embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3C are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3C of the centrifugal blower 1C according to the fourth embodiment will be mainly described with reference to FIG. The bell mouth 3C represents an example in which a general bell mouth is enlarged in the radial direction.

The bell mouth 3C of the centrifugal blower 1C has wall portions that form curved surfaces having different radii of curvature between the upstream end portion 3a and the downstream end portion 3b. As shown in FIG. 7, the bell mouth 3C has a first wall S1 that is continuously and integrally formed from the downstream end 3b to the upstream end 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3C. And a second wall portion S2 and a third wall portion S3. The first wall portion S1, the second wall portion S2, and the third wall portion S3 form a curved surface that is convex toward the inner diameter side of the bell mouth 3C. The first wall portion S1, the second wall portion S2, and the third wall portion S3 are each formed in an arc shape in the vertical cross section of the bell mouth 3C, and form curved surfaces having different curvature radii. Here, in the vertical cross section of the bell mouth 3C, the radius of curvature of the first wall portion S1 is the first radius of curvature a, the radius of curvature of the second wall portion S2 is the second radius of curvature b, and the radius of curvature of the third wall portion S3 is It is defined as the third radius of curvature c. The bell mouth 3C is configured such that the first wall portion S1, the second wall portion S2, and the third wall portion S3 satisfy the relationship of third curvature radius c>first curvature radius a>second curvature radius b. ..

[Effect of centrifugal blower 1C]
The bell mouth 3C expands a general bell mouth in the radial direction. The centrifugal blower 1C has a shape in which a wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in a direction away from the first outline L1 on the basis of the intersection EC in the vertical cross section of the bell mouth 3C. Further, the bell mouth 3C has a first wall portion S1, a second wall portion S2, and a third wall portion S3 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3C. Then, the bell mouth 3C is configured such that the first wall portion S1, the second wall portion S2, and the third wall portion S3 satisfy the relationship of third curvature radius c>first curvature radius a>second curvature radius b. To be done. Therefore, in the bell mouth 3C, the fast airflow flowing into the bell mouth 3C is caused to follow the third wall portion S3 having the large third curvature radius c on the outer peripheral side, and then the second mouth having the smallest second curvature radius b. The wall S2 allows the air flow to follow the bell mouth 3C as it is. Further, the bell mouth 3C has the first wall portion S1 having the second largest radius of curvature a and diverts the flow in the axial direction of the rotation axis RS without difficulty. Due to the bell mouth 3C having the configuration and the function, it is possible to suppress the separation of the airflow from the outer edge portion to the inner edge portion, and to suppress the inflow of the disturbed airflow into the impeller 2, thereby suppressing the noise. You can Further, in the bell mouth 3C, separation of the airflow near the downstream end portion 3b, which is the innermost diameter, is suppressed, and the disturbed airflow into the impeller 2 can be suppressed, so that the centrifugal blower 1C efficiently takes in air. be able to.

Embodiment 5.
FIG. 8 is a partially enlarged view of bell mouth 3D of centrifugal blower 1D according to the fifth embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. 1 to 7 are designated by the same reference numerals and the description thereof will be omitted. The centrifugal blower 1D according to the fifth embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3D are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3D of the centrifugal blower 1D according to the fifth embodiment will be mainly described with reference to FIG. The bell mouth 3D represents an example in which a general bell mouth is enlarged in the radial direction.

The bell mouth 3D of the centrifugal blower 1D has walls that form curved surfaces with different radii of curvature between the upstream end 3a and the downstream end 3b. As shown in FIG. 8, the bell mouth 3D has a first wall S11 that is integrally formed continuously from the downstream end 3b to the upstream end 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3D. And a second wall S12. The first wall portion S11 and the second wall portion S12 form a curved surface that is convex toward the inner diameter side of the bell mouth 3D. The first wall portion S11 and the second wall portion S12 are each formed in an arc shape in the vertical cross section of the bell mouth 3D, and form curved surfaces having different curvature radii. Here, in the vertical cross section of the bell mouth 3D, the radius of curvature of the first wall portion S11 is defined as the first radius of curvature a1 and the radius of curvature of the second wall portion S12 is defined as the second radius of curvature c1. The bellmouth 3D is configured such that the first wall portion S11 and the second wall portion S12 satisfy the relationship of second curvature radius c1>first curvature radius a1.

[Effect of centrifugal blower 1D]
The bell mouth 3D expands a general bell mouth in the radial direction. The centrifugal blower 1D has a shape in which a wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in a direction away from the first outer shape line L1 on the basis of the intersection EC in the vertical cross section of the bell mouth 3D. Further, the bell mouth 3D has a first wall portion S11 and a second wall portion S12 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3D. The two wall portions S12 are configured to satisfy the relationship of the second curvature radius c1>the first curvature radius a1. Therefore, in the bell mouth 3D, the fast airflow flowing into the bell mouth 3D is caused to follow the second wall portion S12 having the large second curvature radius c1 on the outer peripheral side, and subsequently, the first wall portion having the large first curvature radius a1. In S11, the flow is naturally turned in the axial direction of the rotation axis RS. The bell mouth 3D having the configuration and the function can suppress the separation of the airflow from the outer edge portion to the inner edge portion, and can suppress the inflow of the turbulent airflow into the impeller 2, thereby suppressing the noise. You can Further, in the bell mouth 3D, the separation of the air flow near the downstream end portion 3b, which is the innermost diameter, is suppressed, and the turbulent air flow into the impeller 2 can be suppressed, so that the centrifugal blower 1D efficiently takes in the air. be able to.

Sixth Embodiment
FIG. 9 is a partially enlarged view of bell mouth 3E of centrifugal fan 1E according to the sixth embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1E and the like in FIGS. 1 to 8 are designated by the same reference numerals and the description thereof will be omitted. The centrifugal blower 1E according to the sixth embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3E are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3E of the centrifugal blower 1E according to the sixth embodiment will be mainly described with reference to FIG. The bell mouth 3E represents an example in which a general bell mouth is enlarged in the axial direction of the rotation axis.

The bell mouth 3E of the centrifugal blower 1E has wall portions that form curved surfaces having different radii of curvature between the upstream end portion 3a and the downstream end portion 3b. As shown in FIG. 9, the bell mouth 3E has a first wall S21 that is integrally formed continuously from the downstream end 3b to the upstream end 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3E. And a second wall portion S22 and a third wall portion S23. The first wall portion S21, the second wall portion S22, and the third wall portion S23 form a curved surface that is convex toward the inner diameter side of the bell mouth 3E. The first wall portion S21, the second wall portion S22, and the third wall portion S23 are each formed in a circular arc shape in the vertical cross section of the bell mouth 3E, and form curved surfaces having different curvature radii. Here, in the vertical cross section of the bell mouth 3E, the radius of curvature of the first wall portion S21 is the first radius of curvature a2, the radius of curvature of the second wall portion S22 is the second radius of curvature b2, and the radius of curvature of the third wall portion S23 is. It is defined as the third radius of curvature c2. The bell mouth 3E is configured such that the first wall portion S21, the second wall portion S22, and the third wall portion S23 satisfy the relationship of the first curvature radius a2>the third curvature radius c2>the second curvature radius b2. ..

[Effect of centrifugal blower 1E]
The bell mouth 3E expands a general bell mouth in the axial direction of the rotating shaft. The centrifugal blower 1E has a shape in which a wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in a direction away from the first outline L1 in the vertical cross section of the bell mouth 3E with the intersection EC as a reference. Further, the bell mouth 3E has a first wall portion S21, a second wall portion S22, and a third wall portion S23 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3E. Then, the bell mouth 3E is configured such that the first wall portion S21, the second wall portion S22, and the third wall portion S23 satisfy the relationship of the first curvature radius a2>the third curvature radius c2>the second curvature radius b2. To be done. Therefore, in the bell mouth 3E, the fast airflow flowing into the bell mouth 3E is caused to follow the third wall portion S23 having the large third curvature radius c2 on the outer peripheral side, and then the second mouth having the smallest second curvature radius b2. The wall portion S22 allows the air flow to follow the bell mouth 3E as it is. Further, the bell mouth 3E has the first wall portion S21 having the first largest radius of curvature a2, and diverts the flow in the axial direction of the rotation axis RS without difficulty. The bell mouth 3E having the configuration and the function can suppress the separation of the airflow from the outer edge portion to the inner edge portion, and can suppress the inflow of the turbulent airflow into the impeller 2, thereby suppressing the noise. You can Further, in the bell mouth 3E, the separation of the airflow near the downstream end portion 3b, which is the innermost diameter, is suppressed, and the turbulent airflow into the impeller 2 can be suppressed, so that the centrifugal blower 1E efficiently takes in the air. be able to.

Embodiment 7.
FIG. 10 is a partially enlarged view of bell mouth 3F of centrifugal fan 1F according to the seventh embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. 1 to 9 are designated by the same reference numerals and the description thereof will be omitted. The centrifugal blower 1F according to the seventh embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configurations of parts other than the bell mouth 3F are the same as those of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3F of the centrifugal blower 1F according to the seventh embodiment will be mainly described with reference to FIG. The bell mouth 3F represents an example in which a general bell mouth is enlarged in the axial direction of the rotation axis.

The bell mouth 3F of the centrifugal blower 1F has wall portions that form curved surfaces with different radii of curvature between the upstream end portion 3a and the downstream end portion 3b. As shown in FIG. 10, the bell mouth 3F has a first wall portion S31 that is continuously and integrally formed from the downstream end portion 3b to the upstream end portion 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3F. And a second wall portion S32. The first wall portion S31 and the second wall portion S32 form a curved surface that is convex toward the inner diameter side of the bell mouth 3F. The first wall portion S31 and the second wall portion S32 are each formed in an arc shape in the vertical cross section of the bell mouth 3F, and form curved surfaces having different radii of curvature. Here, in the vertical cross section of the bell mouth 3F, the radius of curvature of the first wall portion S31 is defined as a first radius of curvature a3, and the radius of curvature of the second wall portion S32 is defined as a second radius of curvature c3. The bell mouth 3F is configured such that the first wall portion S31 and the second wall portion S32 satisfy the relationship of the first curvature radius a3>the second curvature radius c3.

[Effect of centrifugal blower 1F]
The bell mouth 3F expands a general bell mouth in the axial direction of the rotating shaft. The centrifugal blower 1F has a shape in which a wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges in a direction away from the first outline L1 in the vertical cross section of the bell mouth 3F with the intersection EC as a reference. Further, the bell mouth 3F has a first wall portion S31 and a second wall portion S32 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3F. The two wall portions S32 are configured to satisfy the relationship of the first curvature radius a3>the second curvature radius c3. Therefore, in the bell mouth 3F, the fast airflow flowing into the bell mouth 3F is caused to follow the second wall portion S32 having the large second curvature radius c3 on the outer peripheral side, and then the first having the largest first curvature radius a1. The wall portion S31 diverts the flow in the axial direction of the rotation axis RS without difficulty. The bell mouth 3F having the configuration and the function can suppress the separation of the airflow from the outer edge portion to the inner edge portion, and can suppress the inflow of the turbulent airflow into the impeller 2, thereby suppressing the noise. You can Further, in the bell mouth 3F, separation of the airflow near the downstream end portion 3b, which is the innermost diameter, is suppressed, and the disturbed airflow into the impeller 2 can be suppressed, so that the centrifugal blower 1E efficiently takes in air. be able to.

Eighth embodiment.
FIG. 11 is a partially enlarged view of bell mouth 3G of centrifugal fan 1G according to the eighth embodiment of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. 1 to 10 are designated by the same reference numerals and the description thereof will be omitted. The centrifugal blower 1G according to the eighth embodiment further specifies the configuration of the bell mouth 3 of the centrifugal blower 1 according to the first embodiment, and the configuration of parts other than the bell mouth 3G is the same as that of the first embodiment. It is similar to the centrifugal blower 1 according to. Therefore, in the following description, the configuration of the bell mouth 3G of the centrifugal blower 1G according to the eighth embodiment will be mainly described with reference to FIG.

The bell mouth 3G has a downstream end 3b arranged on a virtual first plane P1 perpendicular to the rotation axis RS. In other words, the downstream end 3b of the bell mouth 3G is formed in a ring shape in the bell mouth 3G, and the virtual first plane P1 including the downstream end 3b formed in a ring shape is with respect to the rotation axis RS. It is a vertical plane. Further, the bell mouth 3G has the upstream end portion 3a arranged on a virtual second plane P2 perpendicular to the rotation axis RS. In other words, the upstream end 3a of the bell mouth 3G is formed in a ring shape in the bell mouth 3G, and the virtual second plane P2 including the upstream end 3a formed in a ring shape is with respect to the rotation axis RS. It is a vertical plane. The virtual first plane P1 and the virtual second plane P2 are parallel to each other.

[Effect of centrifugal blower 1G]
As described above, in the bell mouth 3G, the downstream end 3b is arranged on the virtual first plane P1 that is perpendicular to the rotation axis RS. Further, the bell mouth 3G has the upstream end portion 3a arranged on a virtual second plane P2 perpendicular to the rotation axis RS. Since the bell mouth 3G has the configuration, pressure fluctuation due to the gas sucked into the centrifugal blower 1G is less likely to occur. Therefore, when the centrifugal blower 1G is mounted on a unit such as an outdoor unit, the influence of the internal pressure loss can be minimized.

Ninth Embodiment
FIG. 12 is a side view of a centrifugal blower 1H according to the ninth embodiment of the present invention. FIG. 13 is a sectional view of the centrifugal blower 1H of FIG. 12 taken along the line BB. FIG. 14 is a sectional view taken along line CC of the centrifugal blower 1H in FIG. It should be noted that parts having the same configurations as those of the centrifugal blower 1 to the centrifugal blower 1G of FIGS. 1 to 11 are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 12, the bell mouth 3 of the centrifugal blower 1H is compared with the position of the tongue portion 43 in the range between the tongue portion 43 and one rotation in the circumferential direction along the rotation direction R of the impeller 2. Thus, the wall portion 3c1 forming the air intake portion 3c has a portion in which the width is expanded in the radial direction. For example, as shown in FIGS. 13 and 14, the bell mouth 3 has a radial width along the rotation direction R of the impeller 2 in the direction from the tongue 43 toward the winding end 41b and back to the tongue 43. Is gradually expanded in the order of W1, W2, and W3, and is gradually reduced in the order of W3, W4, and W1.

That is, while the bell mouth 3 rotates once along the rotation direction R of the impeller 2 from the tongue portion 43, the width of the wall portion 3c1 of the air intake portion 3c gradually increases in the radial direction and reaches the maximum. The width of the wall portion 3c1 is gradually returned to the original size while returning from the enlarged position to the tongue portion 43. The configuration of the bell mouth 3 shown in FIGS. 12, 13 and 14 is an example. In the circumferential direction of the bell mouth 3, the position where the width of the wall portion 3c1 of the air intake portion 3c is maximized in the radial direction is determined by, for example, the relationship with the device in which the centrifugal blower 1H is installed. In addition, the bell mouth 3 shown in FIGS. 13 and 14 has the same configuration with the suction ports 5 on both sides of the double suction type centrifugal blower 1, but each suction port 5 has a wall portion 3c1 having a different expanded width. The bell mouth 3 may be included.

Further, the bell mouth 3 expands in the radial direction in the width of the wall portion 3c1 of the air intake portion 3c in a range in which the bell mouth 3 makes one rotation in the circumferential direction along the rotation direction R of the impeller 2 from the tongue portion 43. At the same time, the radius of curvature on the inner peripheral side of the wall portion 3c1 is gradually increased. The wall portion 3c1 of the air intake portion 3c has the maximum radius of curvature on the inner peripheral side in the range in which the wall portion 3c1 rotates in the circumferential direction from the tongue portion 43 in the circumferential direction R of the impeller 2 once. Have parts. The inner peripheral side is a portion of the wall portion 3c1 of the air intake portion 3c in a range closer to the downstream end portion 3b than the upstream end portion 3a.

Further, the air intake portion 3c of the bell mouth 3 has a radial width of the wall portion 3c1 in the circumferential direction while returning from the portion of the wall portion 3c1 having the maximum radius of curvature on the inner peripheral side to the tongue portion 43. While being reduced, the radius of curvature of the inner peripheral side of the wall portion 3c1 is gradually reduced. In the air intake portion 3c of the bell mouth 3, the curvature radius on the inner circumference side gradually increases in the circumferential direction while returning from the wall portion 3c1 having the maximum curvature radius on the inner circumference side to the tongue portion 43. The tongue portion 43 is formed so as to return to the original radius of curvature.

That is, in the bell mouth 3, in the circumferential direction, the width of the wall portion 3c1 of the air intake portion 3c increases in the radial direction and the radius of curvature on the inner circumferential side of the wall portion 3c1 increases, so that the radial direction of the wall portion 3c1 increases. The width is reduced and the radius of curvature on the inner peripheral side of the wall portion 3c1 is reduced. As described above, the configuration of the bell mouth 3 shown in FIGS. 12, 13, and 14 is an example. In the circumferential direction of the bell mouth 3, the position where the radius of curvature on the inner circumferential side of the wall portion 3c1 of the air intake portion 3c has the maximum value is determined by, for example, the relationship with the device in which the centrifugal blower 1H is installed. .. In addition, the bell mouth 3 shown in FIGS. 13 and 14 has the same configuration with the suction ports 5 on both sides of the double suction type centrifugal blower 1, but each suction port 5 has a wall portion 3c1 having a different curvature radius. The bell mouth 3 may be included.

In the bell mouth 3, the formation position of the upstream end portion 3a of the bell mouth 3 with respect to the main plate 2a of the impeller 2 changes as the radius of curvature on the inner peripheral side of the wall portion 3c1 forming the air intake portion 3c increases. There is. More specifically, in the circumferential direction of the bell mouth 3, the distance between the upstream end portion 3a of the bell mouth 3 and the main plate 2a of the impeller 2 increases as the radius of curvature of the inner peripheral side of the wall portion 3c1 increases. .. That is, the position of the upstream end portion 3 a of the bell mouth 3 with respect to the main plate 2 a of the impeller 2 changes along the rotation direction R of the impeller 2.

[Effect of centrifugal blower 1H]
The bell mouth 3 of the centrifugal blower 1H expands the size of the radial wall of the air intake portion 3c at positions other than the tongue portion 43 in the circumferential direction, and the radius of curvature of the bell mouth 3 on the inner peripheral side increases. Is formed. The centrifugal blower 1H has the configuration described above, and thereby reduces the separation of the fast airflow flowing through the bell mouth 3 from the bell mouth 3. Therefore, the centrifugal blower 1H can improve the blowing efficiency and reduce noise.

Embodiment 10.
[Blower 30]
FIG. 15: is a figure which shows the structure of the air blower 30 which concerns on Embodiment 10 of this invention. Parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. The air blower 30 according to the tenth embodiment is, for example, a ventilation fan, a desk fan, or the like. The blower 30 includes any one of the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments, and a case 7 that houses the centrifugal blower 1 and the like. In the following description, when the centrifugal blower 1 is referred to, any one of the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments is used. The case 7 has two openings, a suction port 71 and a discharge port 72. As shown in FIG. 15, the blower device 30 is formed at a position where the suction port 71 and the discharge port 72 face each other. The blower device 30 is not necessarily formed at a position where the suction port 71 and the discharge port 72 face each other, such that one of the suction port 71 and the discharge port 72 is formed above or below the centrifugal blower 1. It does not have to be. In the case 7, a partition plate 73 partitions a space SP1 having a portion where the suction port 71 is formed and a space SP2 having a portion where the discharge port 72 is formed. The centrifugal blower 1 is installed such that the suction port 5 is located in the space SP1 on the side where the suction port 71 is formed and the discharge port 42a is located in the space SP2 on the side where the discharge port 72 is formed.

In the blower device 30, when the impeller 2 is rotated by driving the motor 6, air is sucked into the case 7 through the suction port 71. The air sucked into the case 7 is guided by the bell mouth 3 and sucked into the impeller 2. The air sucked into the impeller 2 is blown out toward the outside in the radial direction of the impeller 2. The air blown from the impeller 2 passes through the inside of the fan casing 4, and then is blown from the discharge port 42 a of the fan casing 4 and the discharge port 72 of the case 7.

Since the blower device 30 according to the tenth embodiment includes the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments, noise can be reduced and air can be taken in efficiently.

Eleventh Embodiment
[Air conditioner 40]
FIG. 16: is a perspective view of the air conditioning apparatus 40 which concerns on Embodiment 11 of this invention. FIG. 17: is a figure which shows the internal structure of the air conditioning apparatus 40 which concerns on Embodiment 11 of this invention. FIG. 18: is sectional drawing of the air conditioning apparatus 40 which concerns on Embodiment 11 of this invention. FIG. 19 is another cross-sectional view of the air conditioning apparatus 40 according to Embodiment 11 of the present invention. It should be noted that parts having the same configurations as those of the centrifugal blower 1 of FIGS. 1 to 15 are designated by the same reference numerals and the description thereof will be omitted. Further, in FIG. 17, the upper surface portion 16a is omitted in order to show the internal configuration of the air conditioner 40. The air conditioner 40 according to the eleventh embodiment is a position facing any one or more of the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments, and the discharge port 42a of the centrifugal blower 1 or the like. And a heat exchanger 10 arranged in the. Further, the air conditioning apparatus 40 according to the eleventh embodiment includes the case 16 installed behind the ceiling of the room to be air-conditioned. In the following description, when the centrifugal blower 1 is referred to, any one of the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments is used. When the bell mouth 3 is indicated, any one of the bell mouth 3 to the bell mouth 3G described above is used.

(Case 16)
As shown in FIG. 16, the case 16 has a rectangular parallelepiped shape including an upper surface portion 16a, a lower surface portion 16b, and a side surface portion 16c. The shape of the case 16 is not limited to a rectangular parallelepiped shape, and may be another shape such as a columnar shape, a prismatic shape, a conical shape, a shape having a plurality of corners, or a shape having a plurality of curved surfaces. It may be. The case 16 has a side surface portion 16c in which a case discharge port 17 is formed, as one of the side surface portions 16c. The case ejection port 17 is formed in a rectangular shape as shown in FIG. The shape of the case discharge port 17 is not limited to the rectangular shape, and may be, for example, a circular shape, an oval shape, or any other shape. The case 16 has a side surface portion 16c in which a case suction port 18 is formed on a surface of the side surface portion 16c, which is a surface behind the surface in which the case discharge port 17 is formed. The case suction port 18 is formed in a rectangular shape as shown in FIG. The shape of the case suction port 18 is not limited to the rectangular shape, and may be, for example, a circular shape, an oval shape, or another shape. A filter for removing dust in the air may be arranged in the case suction port 18.

Inside the case 16, two centrifugal blowers 1, a fan motor 9, and a heat exchanger 10 are housed. The centrifugal blower 1 includes an impeller 2 and a fan casing 4 in which a bell mouth 3 is formed. The fan motor 9 is supported by a motor support 9a fixed to the upper surface 16a of the case 16. The fan motor 9 has an output shaft 6a. The output shaft 6a is arranged so as to extend parallel to the surface of the side surface portion 16c on which the case suction port 18 is formed and the surface on which the case discharge port 17 is formed. In the air conditioner 40, as shown in FIG. 17, two impellers 2 are attached to the output shaft 6a. The impeller 2 forms a flow of air that is sucked into the case 16 from the case suction port 18 and is blown from the case discharge port 17 to the air-conditioned space. The centrifugal blower 1 arranged in the case 16 is not limited to two, and may be one or three or more. In the centrifugal blower 1 used in the air conditioner 40, the above-described configuration of changing the curvature of the bell mouth 3 can be applied to the entire circumference of the bell mouth 3, but the case suction is included in the entire circumference of the bell mouth 3. When applied to the portion facing the mouth 18, the above-mentioned effects are more remarkably exhibited. That is, it is effective to apply the above-described configuration of changing the curvature of the bell mouth 3 to a portion of the entire circumference of the bell mouth 3 where the flow rate of the airflow flowing into the bell mouth 3 increases.

As shown in FIG. 17, the centrifugal blower 1 is attached to the partition plate 19, and the inner space of the case 16 includes a space SP11 on the suction side of the fan casing 4 and a space SP12 on the blowout side of the fan casing 4. It is partitioned by a partition plate 19.

As shown in FIG. 18, the heat exchanger 10 is arranged at a position facing the discharge port 42a of the centrifugal blower 1, and is arranged in the case 16 on the air passage of the air discharged by the centrifugal blower 1. The heat exchanger 10 adjusts the temperature of the air sucked into the case 16 through the case suction port 18 and blown from the case discharge port 17 into the air-conditioned space. The heat exchanger 10 may have a known structure. Further, the case suction port 18 may be formed at a position vertical to the axial direction of the rotation axis RS of the centrifugal blower 1. For example, as shown in FIG. 19, the case suction port 18a is formed on the lower surface portion 16b. Good. In this case, the configuration of the curvature change of the bell mouth 3 described above can be applied to the entire circumference of the bell mouth 3 in the centrifugal blower 1 used in the air conditioner 40. When applied to the portion facing the suction port 18a, the above-mentioned effects are more remarkably exhibited. That is, it is effective to apply the above-described configuration of changing the curvature of the bell mouth 3 to a portion of the entire circumference of the bell mouth 3 where the flow rate of the airflow flowing into the bell mouth 3 increases.

When the impeller 2 is rotated by driving the motor 6, the air in the air-conditioned space is sucked into the case 16 through the case suction port 18 or the case suction port 18a. The air sucked into the case 16 is guided by the bell mouth 3 and sucked into the impeller 2. The air sucked into the impeller 2 is blown out toward the outside in the radial direction of the impeller 2. The air blown out from the impeller 2 passes through the inside of the fan casing 4, then is blown out from the discharge port 42 a of the fan casing 4, and is supplied to the heat exchanger 10. The air supplied to the heat exchanger 10 is heat-exchanged when passing through the heat exchanger 10, and the temperature and humidity are adjusted. The air that has passed through the heat exchanger 10 is blown out from the case outlet 17 into the air-conditioned space.

Since the air conditioner 40 according to the eleventh embodiment includes the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments, noise can be reduced and air can be taken in efficiently.

Twelfth Embodiment
[Refrigeration cycle device 50]
20: is a figure which shows the structure of the refrigerating-cycle apparatus 50 which concerns on Embodiment 12 of this invention. In addition, as the indoor unit 200 of the refrigeration cycle apparatus 50 according to the twelfth embodiment, the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments are used. Further, in the following description, the refrigeration cycle device 50 is described as being used for air conditioning purposes, but the refrigeration cycle device 50 is not limited to being used for air conditioning purposes. The refrigeration cycle device 50 is used for refrigerating or air conditioning applications such as a refrigerator or a freezer, a vending machine, an air conditioner, a refrigerating device, and a water heater.

The refrigeration cycle device 50 according to the twelfth embodiment heats or cools the room to perform air conditioning by transferring heat between the outside air and the air in the room via the refrigerant. The refrigeration cycle device 50 according to the twelfth embodiment includes an outdoor unit 100 and an indoor unit 200. In the refrigeration cycle device 50, the outdoor unit 100 and the indoor unit 200 are pipe-connected by a refrigerant pipe 300 and a refrigerant pipe 400 to form a refrigerant circuit in which a refrigerant circulates. The refrigerant pipe 300 is a gas pipe through which a vapor-phase refrigerant flows, and the refrigerant pipe 400 is a liquid pipe through which a liquid-phase refrigerant flows. Note that a gas-liquid two-phase refrigerant may flow through the refrigerant pipe 400. In the refrigerant circuit of the refrigeration cycle device 50, the compressor 101, the flow path switching device 102, the outdoor heat exchanger 103, the expansion valve 105, and the indoor heat exchanger 201 are sequentially connected via the refrigerant pipe.

(Outdoor unit 100)
The outdoor unit 100 has a compressor 101, a flow path switching device 102, an outdoor heat exchanger 103, and an expansion valve 105. The compressor 101 compresses the drawn refrigerant and discharges it. Here, the compressor 101 may include an inverter device, and the inverter device may change the operating frequency to change the capacity of the compressor 101. The capacity of the compressor 101 is the amount of refrigerant sent out per unit time. The flow path switching device 102 is, for example, a four-way valve, and is a device that switches the direction of the refrigerant flow path. The refrigeration cycle device 50 can realize the heating operation or the cooling operation by switching the flow of the refrigerant using the flow path switching device 102 based on the instruction from the control device 110.

The outdoor heat exchanger 103 exchanges heat between the refrigerant and the outdoor air. The outdoor heat exchanger 103 functions as an evaporator during heating operation, and performs heat exchange between the low-pressure refrigerant flowing from the refrigerant pipe 400 and the outdoor air to evaporate and evaporate the refrigerant. During the cooling operation, the outdoor heat exchanger 103 functions as a condenser, and performs heat exchange between the refrigerant that has been compressed by the compressor 101 that has flowed in from the flow path switching device 102 side and the outdoor air, and removes the refrigerant. Condensate and liquefy. The outdoor heat exchanger 103 is provided with an outdoor blower 104 in order to improve the efficiency of heat exchange between the refrigerant and the outdoor air. The outdoor blower 104 may be equipped with an inverter device to change the operating frequency of the fan motor to change the rotation speed of the fan. The expansion valve 105 is an expansion device (flow rate control means), and functions as an expansion valve by adjusting the flow rate of the refrigerant flowing through the expansion valve 105, and adjusts the pressure of the refrigerant by changing the opening. For example, when the expansion valve 105 is composed of an electronic expansion valve or the like, the opening degree is adjusted based on an instruction from the control device 110.

(Indoor unit 200)
The indoor unit 200 has an indoor heat exchanger 201 that performs heat exchange between the refrigerant and indoor air, and an indoor blower 202 that adjusts the flow of air through which the indoor heat exchanger 201 performs heat exchange. The indoor heat exchanger 201 acts as a condenser during the heating operation, and performs heat exchange between the refrigerant flowing from the refrigerant pipe 300 and the indoor air to condense and liquefy the refrigerant, and to the refrigerant pipe 400 side. Drain. The indoor heat exchanger 201 functions as an evaporator during cooling operation, performs heat exchange between the refrigerant that has been brought to a low pressure state by the expansion valve 105 and indoor air, and causes the refrigerant to deprive the heat of the air to evaporate. To vaporize and flow out to the refrigerant pipe 300 side. The indoor blower 202 is provided so as to face the indoor heat exchanger 201. As the indoor blower 202, any one or more of the centrifugal blower 1 to the centrifugal blower 1H according to the first to eighth embodiments is applied. The operation speed of the indoor blower 202 is determined by the user setting. An inverter device may be attached to the indoor blower 202 to change the operating frequency of a fan motor (not shown) to change the rotation speed of the impeller 2.

[Operation Example of Refrigeration Cycle Device 50]
Next, a cooling operation operation will be described as an operation example of the refrigeration cycle apparatus 50. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 101 flows into the outdoor heat exchanger 103 via the flow path switching device 102. The gas refrigerant flowing into the outdoor heat exchanger 103 is condensed by heat exchange with the outside air blown by the outdoor blower 104, becomes a low-temperature refrigerant, and flows out from the outdoor heat exchanger 103. The refrigerant flowing out of the outdoor heat exchanger 103 is expanded and decompressed by the expansion valve 105 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flows into the indoor heat exchanger 201 of the indoor unit 200, evaporates by heat exchange with the indoor air blown by the indoor blower 202, and becomes a low-temperature low-pressure gas refrigerant to become the indoor heat exchanger. It flows out from 201. At this time, the indoor air cooled by the heat absorbed by the refrigerant becomes conditioned air and is blown out from the discharge port of the indoor unit 200 to the air-conditioned space. The gas refrigerant flowing out from the indoor heat exchanger 201 is sucked into the compressor 101 via the flow path switching device 102 and is compressed again. The above operation is repeated.

Next, a heating operation operation will be described as an operation example of the refrigeration cycle apparatus 50. The high-temperature and high-pressure gas refrigerant compressed and discharged by the compressor 101 flows into the indoor heat exchanger 201 of the indoor unit 200 via the flow path switching device 102. The gas refrigerant flowing into the indoor heat exchanger 201 is condensed by heat exchange with the indoor air blown by the indoor blower 202, becomes a low-temperature refrigerant, and flows out from the indoor heat exchanger 201. At this time, the room air heated by receiving heat from the gas refrigerant becomes conditioned air and is blown out from the discharge port of the indoor unit 200 to the air conditioned space. The refrigerant flowing out from the indoor heat exchanger 201 is expanded and decompressed by the expansion valve 105 to become a low-temperature low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant flows into the outdoor heat exchanger 103 of the outdoor unit 100, evaporates by heat exchange with the outside air blown by the outdoor blower 104, and becomes a low-temperature low-pressure gas refrigerant to become the outdoor heat exchanger 103. Drained from. The gas refrigerant flowing out of the outdoor heat exchanger 103 is sucked into the compressor 101 via the flow path switching device 102 and is compressed again. The above operation is repeated.

Since the refrigeration cycle apparatus 50 according to the twelfth embodiment includes the centrifugal blower 1 to the centrifugal blower 1H according to the first to ninth embodiments, noise can be reduced and air can be taken in efficiently.

The configurations shown in the above embodiments show an example of the content of the present invention, and can be combined with other known techniques, and the configurations of the configurations are possible without departing from the gist of the present invention. It is also possible to omit or change parts. For example, in the fourth embodiment, the bell mouth 3C has a first wall portion integrally formed continuously from the downstream end portion 3b to the upstream end portion 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3C. It has S1, the 2nd wall S2, and the 3rd wall S3. The bell mouth 3C has three wall portions with different radii of curvature, but the bell mouth 3C may have four or more wall portions with different radii of curvature. Similarly, in the sixth embodiment, the bell mouth 3E has a first wall continuously and integrally formed from the downstream end 3b to the upstream end 3a, that is, from the inner peripheral side to the outer peripheral side of the bell mouth 3E. It has a part S21, a second wall part S22, and a third wall part S23. The bell mouth 3E has three wall portions with different radii of curvature, but the bell mouth 3E may have four or more wall portions with different radii of curvature.

1 centrifugal blower, 1A centrifugal blower, 1B centrifugal blower, 1C centrifugal blower, 1D centrifugal blower, 1E centrifugal blower, 1F centrifugal blower, 1G centrifugal blower, 1H centrifugal blower, 2 impeller, 2a main plate, 2a1, peripheral portion, 2b shaft part 2c side plate, 2d blade, 2e suction port, 3 bell mouth, 3A bell mouth, 3B bell mouth, 3C bell mouth, 3D bell mouth, 3E bell mouth, 3F bell mouth, 3G bell mouth, 3a upstream end, 3b downstream End part, 3c air intake part, 3c1 wall part, 4 fan casing, 4a side wall, 4c peripheral wall, 5 suction port, 6 motor, 6a output shaft, 7 case, 9 fan motor, 9a motor support, 10 heat exchanger, 16 cases, 16a upper surface part, 16b lower surface part, 16c side surface part, 17 case discharge port, 18 case suction port, 18a case suction port, 19 partition plate, 30 air blower, 40 air conditioner, 41 scroll part, 41a winding start Part, 41b winding end part, 42 discharge part, 42a discharge port, 42b extended plate, 42c diffuser plate, 42d first side plate, 42e second side plate, 43 tongue part, 50 refrigeration cycle device, 71 suction port, 72 discharge port , 73 partition plate, 100 outdoor unit, 101 compressor, 102 flow path switching device, 103 outdoor heat exchanger, 104 outdoor blower, 105 expansion valve, 110 control device, 200 indoor unit, 201 indoor heat exchanger, 202 indoor blower , 300 refrigerant piping, 400 refrigerant piping.

Claims

An impeller having a disk-shaped main plate and a plurality of blades installed on a peripheral portion of the main plate,
A fan casing that houses the impeller and has a bell mouth that rectifies the gas sucked into the impeller;
Equipped with
The bell mouth is
An air intake formed to form a suction port through which the gas flowing into the fan casing passes, and the opening diameter of which gradually decreases from the upstream end toward the downstream end in the direction of the air flow sucked into the fan casing. Has a recess,
In the vertical cross section of the bell mouth, one of the upstream end and the downstream end is an end of the long axis, the other end is an end of the short axis, and the long axis and the short axis. The intersection with the axis defines a virtual ellipse located on the outer peripheral side with respect to the rotation axis of the impeller from the downstream end,
In the outline of the ellipse, when the outline of the shortest distance connecting the upstream end and the downstream end is defined as the first outline,
The air intake section,
Within the range surrounded by a virtual first tangent line that contacts the upstream end of the ellipse, a virtual second tangent line that contacts the downstream end of the ellipse, and the first outline, the intersection is a reference. As a centrifugal blower, a wall portion between the upstream end portion and the downstream end portion swells in a direction away from the first outline.
The ellipse is
The vertical axis of the bell mouth comprises the minor axis extending from the upstream end into the fan casing, and the major axis extending from the downstream end in a direction parallel to a radial direction of the impeller. Centrifugal blower described in.
The ellipse is
The vertical axis of the bell mouth comprises the long axis extending from the upstream end into the fan casing, and the short axis extending from the downstream end in a direction parallel to the radial direction of the impeller. Centrifugal blower described in.
In the vertical section of the bell mouth,
The distance between the upstream end and the intersection of the ellipse is defined as the first axial distance,
When the distance between the downstream end and the intersection of the ellipse is defined as the first radial distance,
The bell mouth is
The centrifugal blower according to claim 1 or 2, wherein the centrifugal blower is formed so as to satisfy a relationship of a first radial direction distance> a first axial direction distance.
In the vertical section of the bell mouth,
The distance between the upstream end and the intersection of the ellipse is defined as the second axial distance,
When the distance between the downstream end and the intersection of the ellipse is defined as the second radial distance,
The bell mouth is
The centrifugal blower according to claim 1 or 3, wherein the centrifugal blower is formed so as to satisfy the relationship of the second radial distance<the second axial distance.
The bell mouth is
A first wall portion, a second wall portion, and a third wall portion that are continuously and integrally formed from the downstream end portion to the upstream end portion,
The first wall portion, the second wall portion, and the third wall portion are each formed in an arc shape in a vertical cross section of the bell mouth, and each form a curved surface having a different radius of curvature,
When the radius of curvature of the first wall is defined as a first radius of curvature, the radius of curvature of the second wall is defined as a second radius of curvature, and the radius of curvature of the third wall is defined as a third radius of curvature,
The bell mouth is
The centrifugal blower according to claim 1 or 2, which satisfies a relationship of third curvature radius>first curvature radius>second curvature radius.
The bell mouth is
A first wall portion and a second wall portion that are continuously and integrally formed from the downstream end portion to the upstream end portion,
The first wall portion and the second wall portion are each formed in an arc shape in a vertical cross section of the bell mouth, and form curved surfaces having different radii of curvature,
When the radius of curvature of the first wall is defined as a first radius of curvature and the radius of curvature of the second wall is defined as a second radius of curvature,
The bell mouth is
The centrifugal blower according to claim 1 or 2, wherein the relationship of the second radius of curvature>the first radius of curvature is satisfied.
The bell mouth is
A first wall portion, a second wall portion, and a third wall portion that are continuously and integrally formed from the downstream end portion to the upstream end portion,
The first wall portion, the second wall portion, and the third wall portion are each formed in an arc shape in a vertical cross section of the bell mouth, and each form a curved surface having a different radius of curvature,
When the radius of curvature of the first wall is defined as a first radius of curvature, the radius of curvature of the second wall is defined as a second radius of curvature, and the radius of curvature of the third wall is defined as a third radius of curvature,
The bell mouth is
The centrifugal blower according to claim 1 or 3, wherein the relationship of the first radius of curvature>the third radius of curvature>the second radius of curvature is satisfied.
The bell mouth is
A first wall portion and a second wall portion that are continuously and integrally formed from the downstream end portion to the upstream end portion,
The first wall portion and the second wall portion are each formed in an arc shape in a vertical cross section of the bell mouth, and form curved surfaces having different radii of curvature,
When the radius of curvature of the first wall is defined as a first radius of curvature and the radius of curvature of the second wall is defined as a second radius of curvature,
The bell mouth is
The centrifugal blower according to claim 1 or 3, wherein the relationship of the first radius of curvature>the second radius of curvature is satisfied.
The bell mouth is
The downstream end is arranged on a virtual first plane perpendicular to the rotation axis of the impeller,
The centrifugal blower according to any one of claims 1 to 9, wherein the upstream end portion is arranged on a second plane parallel to the first plane.
The air intake section,
It is formed so as to expand radially in comparison with the position of the tongue and to have a larger radius of curvature on the inner peripheral side during one round in the circumferential direction along the rotation direction of the impeller from the tongue. The centrifugal blower according to any one of claims 1 to 10, further comprising a portion having
A centrifugal blower according to any one of claims 1 to 11,
A case accommodating the centrifugal blower,
Blower equipped with.
A centrifugal blower according to any one of claims 1 to 11,
A heat exchanger arranged at a position facing the discharge port of the centrifugal blower,
An air conditioner equipped with.
A refrigeration cycle apparatus equipped with the centrifugal blower according to any one of claims 1 to 11.