JP7130061B2 - Centrifugal blowers, blowers, air conditioners and refrigeration cycle devices - Google Patents

Description

TECHNICAL FIELD The present invention relates to a centrifugal fan having a casing with a bell mouth, and a fan, air conditioner, and refrigeration cycle device having the same.

Conventionally, the bell mouth of a centrifugal fan has a curved surface formed by a wall that shrinks from the outer peripheral side to the inner peripheral direction, and a wall located downstream of the curved surface from the intake air and expanding from the inner peripheral side to the outer peripheral direction. There has been proposed a centrifugal fan having a curved surface composed of (see, for example, Patent Document 1). Here, in the centrifugal fan, the curvature radius of the curved surface in the direction of contraction 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 expanding 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 fan of Patent Document 1, the shape of the bell mouth has a relationship of curvature radius Y>curvature radius Z, so that the air flow is smooth at the suction port and noise can be improved.

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

However, if the bell mouth is swollen in the radial direction or in the axial direction of the rotating shaft to further improve the characteristics, the radius of curvature of the curved surface of the bell mouth becomes small, so the airflow is likely to separate from the bell mouth, resulting in noise. may worsen.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-described problems, and provides a centrifugal blower capable of reducing noise even when the bell mouth is swollen in the radial direction or in the axial direction of the rotating shaft. The present invention provides a blower, an air conditioner, and a refrigeration cycle device.

A centrifugal fan according to the present invention includes an impeller having a disk-shaped main plate and a plurality of blades installed on the peripheral edge of the main plate, and housing the impeller to rectify gas sucked into the impeller. a fan casing having a bell mouth, the bell mouth forming a suction port through which air flowing into the fan casing passes, and extending from the upstream end toward the downstream end in the direction of the air flow sucked into the fan casing. The opening diameter is formed to gradually decrease, and the bell mouth has an air intake portion that is formed in a curved shape that draws an arc in the vertical cross section. One end is the end of the long axis, the other end is the end of the short axis, and the intersection of the long axis and the short axis is located on the outer peripheral side of the rotating shaft of the impeller relative to the downstream end. A virtual ellipse is defined, and 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 part is the upstream end of the ellipse. Within the range surrounded by the virtual first tangent line that contacts the ellipse, the virtual second tangent line that contacts the downstream end of the ellipse, and the first outline, the distance between the upstream end and the downstream end with respect to the intersection point The wall portion bulges in a direction away from the first outline.

In the centrifugal fan according to the present invention, the air intake portion is surrounded by a virtual first tangent line in contact with the upstream end of the ellipse, a virtual second tangent line in contact with the downstream end of the ellipse, and a first outline. Within the range, the wall portion between the upstream end portion and the downstream end portion bulges in the direction away from the first outline with reference to the intersection point. Since the centrifugal fan has this 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 allows the fast airflow flowing into the bell mouth to flow from the outer peripheral side to the inner peripheral side of the bell mouth, so that the gas flow can be naturally deflected in the axial direction at the air intake portion. As a result, the centrifugal fan can suppress separation of the airflow near the downstream end, which is the innermost diameter of the bell mouth, and can suppress the inflow of turbulent airflow into the impeller, thereby suppressing noise. can be done.

1 is a perspective view of a centrifugal fan according to Embodiment 1 of the present invention; FIG. It is the side view which looked at the centrifugal fan of FIG. 1 from the inlet port side. FIG. 3 is a partial cross-sectional view of the centrifugal blower of FIG. 2 taken along the line AA; FIG. 4 is an enlarged view of the B portion of the bell mouth of FIG. 3; FIG. 7 is a partially enlarged view of a bellmouth of a centrifugal fan according to Embodiment 2 of the present invention; FIG. 11 is a partially enlarged view of a bellmouth of a centrifugal fan according to Embodiment 3 of the present invention; FIG. 11 is a partially enlarged view of a bell mouth of a centrifugal fan according to Embodiment 4 of the present invention; FIG. 11 is a partially enlarged view of a bell mouth of a centrifugal fan according to Embodiment 5 of the present invention; FIG. 11 is a partially enlarged view of a bell mouth of a centrifugal fan according to Embodiment 6 of the present invention; FIG. 11 is a partially enlarged view of a bellmouth of a centrifugal fan according to Embodiment 7 of the present invention; FIG. 11 is a partially enlarged view of a bell mouth of a centrifugal fan according to Embodiment 8 of the present invention; FIG. 11 is a side view of a centrifugal fan according to Embodiment 9 of the present invention; FIG. 13 is a cross-sectional view of the centrifugal fan of FIG. 12 taken along the line BB. FIG. 13 is a cross-sectional view of the centrifugal fan of FIG. 12 taken along the line CC. FIG. 20 is a diagram showing the configuration of a blower device according to Embodiment 10 of the present invention; FIG. 20 is a perspective view of an air conditioner according to Embodiment 11 of the present invention. FIG. 20 is a diagram showing the internal configuration of an air conditioner according to Embodiment 11 of the present invention. FIG. 11 is a cross-sectional view of an air conditioner according to Embodiment 11 of the present invention. FIG. 21 is another cross-sectional view of the air conditioner according to Embodiment 11 of the present invention. FIG. 20 is a diagram showing the configuration of a refrigeration cycle apparatus according to Embodiment 12 of the present invention;

Centrifugal blower 1 to centrifugal blower 1H, blower 30, air conditioner 40, and refrigeration cycle device 50 according to embodiments of the present invention will be described below with reference to the drawings. In the following drawings including FIG. 1, the relative dimensional relationship and shape of each constituent member may differ from the actual ones. Moreover, in the following drawings, the same reference numerals denote the same or corresponding parts, and this applies throughout the specification. In order to facilitate understanding, terms representing directions (eg, "up", "down", "right", "left", "front", "back", etc.) are used as appropriate. For convenience of explanation only, such description is not intended to limit the arrangement and orientation of devices or components.

Embodiment 1.
[Centrifugal blower 1]
FIG. 1 is a perspective view of a centrifugal fan 1 according to Embodiment 1 of the present invention. FIG. 2 is a side view of the centrifugal fan 1 of FIG. 1 as seen from the suction port 5 side. FIG. 3 is a partial cross-sectional view of the centrifugal fan 1 of FIG. 2 taken along line AA. The arrows shown in FIG. 3 indicate the flow of air flowing through the centrifugal fan 1. As shown in FIG. The basic structure of the centrifugal fan 1 will be described with reference to FIGS. 1 to 3. FIG. A centrifugal fan 1 is, for example, a multi-blade centrifugal fan 1 such as a sirocco fan or a turbo fan, and has an impeller 2 that generates airflow 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 forces the air radially outward. As shown in FIG. 1, the impeller 2 has a disk-shaped main plate 2a and a plurality of blades 2d installed on a peripheral edge portion 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.

3, in the axial direction of the rotation axis RS of the shaft portion 2b, the impeller 2 has a ring-shaped side plate 2c facing the main plate 2a at the 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. Note that the impeller 2 may have a structure without the side plate 2c. When the impeller 2 has the side plate 2c, each of the plurality of blades 2d has one end connected to the main plate 2a and the other end 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 configured in a cylindrical shape by a main plate 2a and a plurality of blades 2d. A suction port 2e of the impeller 2 is provided on the side plate 2c opposite to the main plate 2a in the axial direction of the rotation axis RS of the shaft portion 2b. forming

2 d of several blade|wings are arrange|positioned at the circumference centering on the axial part 2b, and the base end is being 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. 2 d of each blade|wing is mutually arrange|positioned at the peripheral edge part 2a1 of the main plate 2a at a fixed space|interval. Each blade 2d is formed, for example, in the shape of a curved rectangular plate, and installed along the radial direction or inclined at a predetermined angle with respect to the radial direction.

The impeller 2 is configured as described above, and when it is rotated, the air sucked into the space surrounded by the main plate 2a and the plurality of blades 2d passes between the blades 2d and the adjacent blades 2d, As shown in FIG. 3, it can be delivered radially outward. In Embodiment 1, each blade 2d is provided so as to rise substantially perpendicularly to the main plate 2a, but the configuration is not limited to this. may be provided slantingly.

(Fan casing 4)
The fan casing 4 surrounds the impeller 2 and rectifies the air blown out 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 that constitutes the impeller 2. and a peripheral wall 4c that radially surrounds the rotating shaft RS. 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. It has a guiding tongue 43 . The radial direction of the shaft portion 2b is a direction perpendicular to the shaft portion 2b. The internal space of the scroll portion 41 defined 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.

(Sidewall 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 side wall 4 a of the fan casing 4 is formed with a suction port 5 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 arranged so that the center of the suction port 5 and the center of the shaft portion 2b of the impeller 2 are substantially aligned. Due to the configuration of the side wall 4 a , 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 fan 1 is a double suction type fan casing having side walls 4a formed with suction ports 5 on both sides of the main plate 2a in the axial direction of the rotation axis RS of the shaft portion 2b. 4. That is, in the centrifugal fan 1, the fan casing 4 has two side walls 4a, and the side walls 4a are arranged so as to face each other.

(Surrounding wall 4c)
The peripheral wall 4c forms an inner peripheral surface that surrounds the impeller 2 in the radial direction of the shaft portion 2b and faces the plurality of blades 2d. The peripheral wall 4 c 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 4 c extends from the winding start portion 41 a located at the boundary between the tongue portion 43 and the scroll portion 41 to the discharge portion 42 on the side away from the tongue portion 43 along the rotation direction R of the impeller 2 . and 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 upstream end portion of the airflow 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 side of the airflow generated by the rotation of the impeller 2. side end.

The peripheral wall 4 c has a width in the axial direction of the rotating shaft 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. be done. That is, in the peripheral wall 4c, the gap between the peripheral wall 4c and the outer periphery of the impeller 2 expands at a predetermined rate from the tongue portion 43 to the discharge portion 42, and the air passage area gradually increases. A spiral shape defined by a predetermined magnification ratio includes, for example, a logarithmic spiral, an Archimedean spiral, or a spiral shape based on an involute curve. 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 the beginning of the spiral shape to a winding end portion 41b that is the end of the spiral shape. . With such a configuration, the air sent out from the impeller 2 smoothly flows in the direction of the discharge portion 42 through the gap between the impeller 2 and the peripheral wall 4c. Therefore, in the fan casing 4 , the static pressure of air efficiently rises from the tongue portion 43 toward the discharge portion 42 .

(Discharging part 42)
The discharge portion 42 forms a discharge port 42a through which the airflow generated by the impeller 2 and passed through the scroll portion 41 is discharged. The discharge part 42 is composed of a hollow tube having a rectangular cross section perpendicular 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 through the gap between the peripheral wall 4c and the impeller 2 so as to be discharged to the outside of the fan casing 4. form a path.

As shown in FIG. 1, the discharge portion 42 includes an extension plate 42b, a diffuser plate 42c, a first side plate 42d, a second side plate 42e, and the like. The extension plate 42b is formed integrally with the peripheral wall 4c so as to smoothly continue to the winding end portion 41b on the downstream side of the peripheral wall 4c. The diffuser plate 42c is formed integrally 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 respect to the extended plate 42b so that the cross-sectional area of the flow path gradually expands along the direction of air flow in the discharge portion 42 . The first side plate 42 d is formed integrally with the side wall 4 a of the fan casing 4 , and the second side plate 42 e is formed integrally with the opposite side wall 4 a of the fan casing 4 . The first side plate 42d and the second side plate 42e facing each other are formed between the extended plate 42b and the diffuser plate 42c. In this manner, the discharge portion 42 has a channel with a rectangular cross section formed by the extension plate 42b, the diffuser plate 42c, the first side plate 42d, and the second side plate 42e.

(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 portion between the scroll portion 41 and the discharge portion 42 and protrudes 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 through the scroll portion 41 to the discharge port 42a.

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 portion 42, the tongue portion 43 serves as a branching point of the air flow path. That is, at the inflow port of the discharge portion 42, an airflow directed toward the discharge port 42a and an airflow re-entering the upstream side from the tongue portion 43 are formed. Further, the static pressure of the air flowing into the discharge portion 42 increases while passing through the fan casing 4 and becomes higher than the inside of 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 due to its curved surface.

(bell mouth 3)
A suction port 5 provided in the side wall 4 a is formed by a bell mouth 3 . The bellmouth 3 rectifies the gas sucked into the impeller 2 and causes it to flow into the suction port 2e of the impeller 2 . The bell mouth 3 is formed such that the diameter of the opening 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 . Bell mouth 3 is formed at a position facing suction port 2 e of impeller 2 . The bellmouth 3 has an air intake portion 3c that guides the airflow sucked into the fan casing 4 into the fan casing 4. As shown in FIG.

The air intake portion 3 c is formed in a cylindrical shape, and the inner peripheral surface of the air intake portion 3 c forms the suction port 5 . Gas flowing into the fan casing 4 from the outside passes through the suction port 5 . The air intake portion 3c has an opening diameter that extends from an upstream end portion 3a, which is an end portion on the upstream side, toward a downstream end portion 3b, which is an end portion on the downstream side, in the direction of the air flow sucked into the fan casing 4 through the suction port 5. It is designed to gradually become smaller. That is, the air intake portion 3c is provided so as to extend in the axial direction of the rotation shaft RS so that the airflow passage that is sucked into the fan casing 4 through the suction port 5 narrows from upstream to downstream. formed.

The bellmouth 3 is annular in plan view in the axial direction of the rotation axis RS, with the upstream end 3a forming an outer edge portion and the downstream end 3b forming an inner edge portion. Therefore, the upstream end portion 3a is the outermost portion of the bell mouth 3 and the most expanded portion of the bell mouth 3 formed in a cylindrical shape. The downstream end 3b is the innermost part of the bell mouth 3, and is the most contracted part of the bell mouth 3 formed in a cylindrical shape.

The air intake portion 3c has an arcuate cross-sectional shape on a rotating surface centered on the axial direction of the rotating shaft RS, and a surface forming the suction port 5 is formed with a curved surface. Therefore, as shown in FIG. 3, in the vertical cross section of the bell mouth 3, the air intake portion 3c has a wall portion 3c1 that forms the suction port 5 and is formed in an arc shape.

FIG. 4 is an enlarged view of the B portion of the bell mouth 3 of FIG. Next, as shown in FIG. 4, a detailed configuration of the bell mouth 3 will be described using a cross-sectional view of the bell mouth 3. As shown in FIG. In addition, the rotating shaft RS is described to explain the positional relationship between the rotating shaft RS, the downstream end portion 3b, and the intersection point EC. In FIG. 4, the ellipse EL is a hypothetical ellipse EL having the upstream end 3a of the bellmouth 3 as the first end E1 of the minor axis MI and the downstream end 3b of the bellmouth 3 as the second end E2 of the major axis MA. Elliptical. In the vertical cross section of the bellmouth 3, the virtual ellipse EL has a minor axis MI extending from the upstream end 3a into the fan casing 4 and a major axis MA extending from the downstream end 3b in a direction parallel to the radial direction of the impeller 2. and The intersection point EC is the intersection point between the minor axis MI and the major axis MA, and is the center point of the virtual ellipse EL.

The upstream end 3 a is the outermost portion of the bell mouth 3 in the radial direction, and the downstream end 3 b is the innermost portion of the bell mouth 3 . In the vertical cross section of the bellmouth 3, the imaginary ellipse EL has one end of the major axis MA and the other end of the minor axis MI of the upstream end 3a and the downstream end 3b. , and the intersection point EC between the major axis MA and the minor axis MI is located on the outer peripheral side of the rotating shaft RS of the impeller 2 relative 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.

A first tangent line HT is a virtual tangent line in contact with the first end E1 of the ellipse EL, and a second tangent line VT is a virtual tangent line in contact with 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 that contacts the downstream end 3b of the ellipse EL.

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

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

The air intake portion 3c is defined by a virtual first tangent line HT in contact with the first end E1 of the ellipse EL, a virtual second tangent line VT in contact with the second end E2 of the ellipse EL, and a first outline L1. It swells within the bounded area.

That is, the air intake portion 3c is defined by a virtual first tangent line HT in contact with the upstream end 3a of the ellipse EL, a virtual second tangent line VT in contact with 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 away from the first outline L1 with reference to the intersection point EC. The bell mouth 3 of the centrifugal blower 1 expands a general bell mouth radially and axially. The centrifugal fan 1 has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b swells in a direction away from the first outline L1 with respect to the intersection point EC. The curvature of the bell mouth 3 near 3b approaches the axial direction.

[Operation of centrifugal blower 1]
When the impeller 2 rotates, air outside the fan casing 4 is drawn into the fan casing 4 through the suction port 5 . Air sucked into the fan casing 4 flows along the air intake portion 3 c of the bell mouth 3 and is sucked into the impeller 2 . The air sucked into the impeller 2 is blown out radially outward of the impeller 2 as an airflow to which dynamic pressure and static pressure are added in the process of passing between the plurality of blades 2d. The airflow blown out from the impeller 2 is guided between the inner side of the peripheral wall 4c and the blades 2d in the scroll portion 41, and the dynamic pressure is converted into static pressure. After passing through the scroll portion 41 , the airflow blown out from the impeller 2 is blown out of the fan casing 4 from a discharge port 42 a formed in the discharge portion 42 .

[Action and effect of the centrifugal blower 1]
The air intake portion 3c is surrounded by a virtual first tangent line HT in contact with the upstream end 3a of the ellipse EL, a virtual second tangent line VT in contact with 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 bulges away from the first outline L1 with reference to the intersection point EC. By providing the centrifugal fan 1 with this configuration, 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 allows the fast airflow flowing into the bell mouth 3 to follow the inner peripheral side from the outer peripheral side of the bell mouth 3, and the gas flow can be turned in the axial direction without difficulty in the air intake portion 3c. . As a result, the centrifugal fan 1 can suppress the separation of the airflow near the downstream end 3b, which is the innermost diameter, in the bell mouth 3, and can suppress the inflow of turbulent airflow into the impeller 2, thereby reducing noise. can be suppressed. In addition, the bellmouth 3 suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1 takes in air efficiently. be able to. If the centrifugal blower 1 according to the first embodiment is not applied, that is, if a general bell mouth is expanded in the radial direction and the axial direction of the rotating shaft, the bell mouth will be shaped along the ellipse EL. The airflow may separate from the bell mouth on the inner peripheral side. The bell mouth 3 of the centrifugal fan 1 according to Embodiment 1 has the above-described configuration, so that it is possible to reduce separation of the airflow near the downstream end 3b, which is the innermost diameter.

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

A first axial distance D1 is defined as a distance between the upstream end 3a and the downstream end 3b of the bellmouth 3A in the axial direction of the rotation axis RS. In other words, when the upstream end 3a and the downstream end 3b of the bell mouth 3A are projected onto the rotation axis RS in a direction perpendicular to the rotation axis RS, the first axial distance D1 is the distance between the rotation axis RS. It is the distance between the upstream end 3a and the downstream end 3b in 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 distance D1 is also the distance between the upstream end 3a and the intersection point EC of the imaginary ellipse EL. A first radial distance D2 is defined as the distance between the upstream end 3a and the downstream end 3b of the bellmouth 3A in the radial direction of the rotation axis RS. In other words, the first radial distance D2 is the distance between the upstream end 3a and the downstream end 3b of the bellmouth 3A appearing on the same imaginary plane in plan view in the axial direction of the rotation axis RS. is. Note that the first radial 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 point EC of the imaginary ellipse EL.

The bellmouth 3A is formed so as to satisfy the relationship of first radial distance D2>first axial distance D1. In the bell mouth 3A, a portion that satisfies the relationship of first radial distance D2>first axial distance D1 may be formed along the entire circumference of the bell mouth 3, or may be partially formed in the circumferential direction. may A bell mouth 3A of the centrifugal blower 1A is a radially enlarged bell mouth. The centrifugal fan 1A has a shape in which 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 respect to the intersection point EC. The curvature of the bell mouth 3A near 3b approaches the axial direction.

[Action and effect of centrifugal blower 1A]
As described above, the bellmouth 3A is formed so as to satisfy the relationship of the first radial distance D2>the first axial distance D1. The centrifugal fan 1A has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC. Therefore, in the centrifugal fan 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. The centrifugal blower 1A allows the fast air current flowing into the bell mouth 3A to flow from the outer peripheral side to the inner peripheral side of the bell mouth 3A, so that the gas flow can be turned in the axial direction without difficulty at the air intake portion 3c. . As a result, the centrifugal fan 1A can suppress separation of the airflow near the downstream end 3b, which is the innermost diameter, in the bellmouth 3A, and can suppress the inflow of turbulent airflow into the impeller 2, thereby reducing noise. can be suppressed. In addition, the bell mouth 3A suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1A takes in air efficiently. be able to. If the centrifugal blower 1A according to the second embodiment is not applied, i.e., if a general bell mouth is expanded in the radial direction, if the shape is along the ellipse EL, the bell mouth will be separated from the bell mouth on the inner peripheral side of the bell mouth. Airflow may detach. The bell mouth 3A of the centrifugal fan 1A having the above configuration can reduce separation of the airflow 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 Embodiment 3 of the present invention. Parts having the same configuration as those of the centrifugal blower 1, etc., shown in FIGS. A centrifugal fan 1B according to the third embodiment further specifies the configuration of the bell mouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of other parts other than the bell mouth 3B is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3B of the centrifugal fan 1B according to the third embodiment will be mainly described with reference to FIG.

In FIG. 6, an ellipse FL is a hypothetical ellipse FL with the upstream end 3a of the bellmouth 3B as the first end G1 of the major axis MA2 and the downstream end 3b of the bellmouth 3B as the second end G2 of the minor axis MI2. Elliptical. More specifically, in the vertical cross section of the bellmouth 3B, the virtual ellipse FL has a major axis MA2 extending from the upstream end 3a into the fan casing 4 and a direction parallel to the radial direction of the impeller 2 from the downstream end 3b. and a minor axis MI2 extending into the . The intersection point EC is the intersection point of the minor axis MI2 and the major axis MA2, and is the center point of the virtual ellipse FL.

In the vertical cross section of the bell mouth 3B, the imaginary ellipse FL has one end of the major axis MA2 and the other end of the minor axis MI2 of the upstream end 3a and the downstream end 3b. , and the intersection point EC between the major axis MA2 and the minor axis MI2 is located on the outer peripheral side of the rotation axis RS of the impeller 2 relative to the downstream end portion 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.

A first tangent line HT2 is a virtual tangent line that contacts the first end G1 of the ellipse FL, and a second tangent line VT2 is a virtual tangent 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 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 is arranged between the upstream end portion 3a and the downstream end portion 3b, with the upstream end portion 3a as the first end G1 of the major axis MA2 and the downstream end portion 3b as the first end portion G1. The imaginary ellipse FL, which is the second end G2 of the minor axis MI2, bulges from the first outline L1 toward the inner circumference of the bell mouth 3B. In other words, the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b of the air intake portion 3c bulges away from the first outline L1 with reference to the intersection point EC. Therefore, as shown in FIG. 6, the air intake portion 3c is formed in a curved shape that draws an arc in the vertical section of the bell mouth 3B.

The air intake portion 3c is defined by a virtual first tangent line HT2 contacting the first end G1 of the ellipse FL, a virtual second tangent line VT2 contacting the second end G2 of the ellipse FL, and the first outline L1. It swells within the bounded area.

That is, the air intake portion 3c is defined by a virtual first tangent line HT2 that contacts the upstream end 3a of the ellipse FL, a virtual second tangent line VT2 that contacts the downstream end 3b of the ellipse FL, 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 away from the first outline L1 with reference to the intersection point EC. The bell mouth 3B of the centrifugal blower 1B is an axially enlarged bell mouth of a general bell mouth. The centrifugal fan 1B has a shape in which 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 respect to the intersection point EC. 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 bellmouth 3B in the axial direction of the rotation axis RS is defined as a second axial distance D3. In other words, the second axial distance D3 is the distance between the upstream end 3a and the downstream end 3b of the bellmouth 3B projected onto the rotational axis RS in a direction perpendicular to the rotational axis RS. It is the distance between the upstream end 3a and the downstream end 3b in 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 point EC of the imaginary ellipse FL. A second radial distance D4 is defined as the 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. 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 appearing on the same imaginary plane in plan view in the axial direction of the rotation axis RS. is. The second radial 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 point EC of the imaginary ellipse FL.

The bellmouth 3B is formed so as to satisfy the relationship of second radial distance D4<second axial distance D3. In the bell mouth 3B, a portion that satisfies the relationship of second radial distance D4<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 A bell mouth 3B of the centrifugal fan 1B is obtained by enlarging a general bell mouth in the axial direction of the rotating shaft RS. The centrifugal fan 1B has a shape in which 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 respect to the intersection point EC. The curvature of the bell mouth 3B in the vicinity of 3b approaches in the axial direction.

[Action and effect of centrifugal blower 1B]
As described above, the bellmouth 3B is formed so as to satisfy the relationship of the second radial distance D4<the second axial distance D3. In the vertical cross section of the bell mouth 3B, the centrifugal fan 1B has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC. . Therefore, in the centrifugal fan 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. The centrifugal blower 1B allows the fast air current flowing into the bell mouth 3B to follow the inner peripheral side from the outer peripheral side of the bell mouth 3B, so that the gas flow can be turned in the axial direction without difficulty in the air intake portion 3c. . As a result, the centrifugal fan 1B can suppress separation of the airflow near the downstream end 3b, which is the innermost diameter, in the bell mouth 3B, and can suppress the inflow of turbulent airflow into the impeller 2, thereby reducing noise. can be suppressed. In addition, the bellmouth 3B suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1B takes in air efficiently. be able to. If the centrifugal blower 1B according to the third embodiment is not applied, that is, if a general bell mouth is enlarged in the axial direction of the rotation shaft, the shape along the ellipse FL is assumed to be the inner peripheral side of the bell mouth. The airflow may separate from the bell mouth. The bell mouth 3B of the centrifugal fan 1B according to Embodiment 3 has the above-described configuration, so that it is possible to reduce separation of the airflow near the downstream end 3b, which is the innermost diameter.

Embodiment 4.
FIG. 7 is a partially enlarged view of a bell mouth 3C of a centrifugal fan 1C according to Embodiment 4 of the present invention. Parts having the same configurations as those of the centrifugal fan 1, etc., shown in FIGS. A centrifugal fan 1C according to the fourth embodiment further specifies the configuration of the bellmouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of parts other than the bellmouth 3C is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3C of the centrifugal fan 1C according to the fourth embodiment will be mainly described with reference to FIG. Note that the bell mouth 3C represents an example in which a general bell mouth is expanded in the radial direction.

A bell mouth 3C of the centrifugal fan 1C has walls forming curved surfaces with different radii of curvature between the upstream end 3a and the downstream end 3b. As shown in FIG. 7, the bell mouth 3C has a first wall portion S1 formed continuously and integrally 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. , 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 protrudes 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 with different curvature radii. Here, in the vertical cross section of the bellmouth 3C, the curvature radius of the first wall portion S1 is the first curvature radius a, the curvature radius of the second wall portion S2 is the second curvature radius b, and the curvature radius of the third wall portion S3 is Define a third radius of curvature c. The bellmouth 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. .

[Action and effect of centrifugal blower 1C]
The bell mouth 3C is a radially enlarged version of a general bell mouth. The centrifugal fan 1C has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC in the vertical cross section of the bell mouth 3C. Also, the bell mouth 3C has a first wall S1, a second wall S2, and a third wall S3 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3C. The bellmouth 3C is configured so 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. be done. Therefore, the bell mouth 3C directs the fast airflow flowing into the bell mouth 3C along the third wall portion S3 having the third large curvature radius c on the outer peripheral side, followed by the second wall portion S3 having the smallest second curvature radius b. The wall portion S2 directs the airflow along the bell mouth 3C as it is. Furthermore, the bellmouth 3C naturally turns the flow in the axial direction of the rotation axis RS at the first wall portion S1 having the second largest first curvature radius a. The bell mouth 3C can suppress the separation of the airflow from the outer edge to the inner edge by having the configuration and action, and can suppress the inflow of turbulent airflow into the impeller 2, thereby suppressing noise. can be done. In addition, the bell mouth 3C suppresses the separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1C takes in air efficiently. be able to.

Embodiment 5.
FIG. 8 is a partially enlarged view of a bell mouth 3D of a centrifugal fan 1D according to Embodiment 5 of the present invention. Parts having the same configuration as those of the centrifugal fan 1 and the like shown in FIGS. A centrifugal fan 1D according to the fifth embodiment further specifies the configuration of the bellmouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of other portions other than the bellmouth 3D is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3D of the centrifugal fan 1D according to the fifth embodiment will be mainly described with reference to FIG. The bell mouth 3D is an example of expanding a general bell mouth in the radial direction.

A bell mouth 3D of the centrifugal fan 1D has walls forming 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 portion S11 formed continuously and integrally 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 3D. and a second wall portion S12. The first wall portion S11 and the second wall portion S12 form a curved surface that protrudes 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 with different curvature radii. Here, in the vertical cross section of the bellmouth 3D, the curvature radius of the first wall portion S11 is defined as a first curvature radius a1, and the curvature radius of the second wall portion S12 is defined as a second curvature radius 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.

[Action and effect of centrifugal blower 1D]
Bellmouth 3D is a radial expansion of a typical bellmouth. The centrifugal fan 1D has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC in the vertical cross section of the bellmouth 3D. Further, the bell mouth 3D has a first wall S11 and a second wall S12 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3D. The second wall portion S12 is configured to satisfy the relationship of second curvature radius c1>first curvature radius a1. Therefore, the bell mouth 3D directs the fast airflow flowing into the bell mouth 3D along the second wall portion S12 having the large second curvature radius c1 on the outer peripheral side, followed by the first wall portion S12 having the large first curvature radius a1. In S11, the flow is naturally turned in the axial direction of the rotating shaft RS. Bell mouth 3D can suppress the separation of the airflow from the outer edge to the inner edge by having the configuration and action, and can suppress the inflow of turbulent airflow into the impeller 2, thereby suppressing noise. can be done. In addition, the bell mouth 3D suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1D takes in air efficiently. be able to.

Embodiment 6.
FIG. 9 is a partially enlarged view of a bell mouth 3E of a centrifugal fan 1E according to Embodiment 6 of the present invention. Parts having the same configurations as those of the centrifugal fan 1E, etc., shown in FIGS. The centrifugal fan 1E according to the sixth embodiment further specifies the configuration of the bellmouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of the portions other than the bellmouth 3E is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3E of the centrifugal fan 1E according to the sixth embodiment will be mainly described with reference to FIG. Note that the bell mouth 3E represents an example in which a general bell mouth is enlarged in the axial direction of the rotating shaft.

A bell mouth 3E of the centrifugal fan 1E has walls forming curved surfaces with different radii of curvature between the upstream end 3a and the downstream end 3b. As shown in FIG. 9, the bell mouth 3E has a first wall portion S21 formed continuously and integrally 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 3E. , 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 protrudes 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 an arc shape in the vertical cross section of the bell mouth 3E, and form curved surfaces with different curvature radii. Here, in the vertical cross section of the bell mouth 3E, the curvature radius of the first wall portion S21 is the first curvature radius a2, the curvature radius of the second wall portion S22 is the second curvature radius b2, and the curvature radius of the third wall portion S23 is It is defined as a third radius of curvature c2. The bellmouth 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 first curvature radius a2>third curvature radius c2>second curvature radius b2. .

[Action and effect of the centrifugal blower 1E]
The bell mouth 3E is a general bell mouth enlarged in the axial direction of the rotating shaft. The centrifugal fan 1E has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC in the vertical cross section of the bellmouth 3E. Also, the bell mouth 3E has a first wall S21, a second wall S22, and a third wall S23 that are continuously and integrally formed from the inner peripheral side to the outer peripheral side of the bell mouth 3E. The bellmouth 3E is configured so that the first wall portion S21, the second wall portion S22, and the third wall portion S23 satisfy the relationship of first curvature radius a2>third curvature radius c2>second curvature radius b2. be done. Therefore, the bell mouth 3E directs the fast airflow flowing into the bell mouth 3E along the third wall portion S23 having the large third curvature radius c2 on the outer peripheral side, followed by the second wall portion S23 having the smallest second curvature radius b2. The wall portion S22 directs the airflow along the bell mouth 3E as it is. Furthermore, the bellmouth 3E naturally turns the flow in the axial direction of the rotation axis RS at the first wall portion S21 having the largest first curvature radius a2. The bellmouth 3E can suppress the separation of the airflow from the outer edge to the inner edge by having the configuration and action, and can suppress the inflow of turbulent airflow into the impeller 2, thereby suppressing noise. can be done. In addition, the bell mouth 3E suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1E takes in air efficiently. be able to.

Embodiment 7.
FIG. 10 is a partially enlarged view of a bell mouth 3F of a centrifugal fan 1F according to Embodiment 7 of the present invention. Parts having the same configurations as those of the centrifugal blower 1 and the like shown in FIGS. The centrifugal fan 1F according to the seventh embodiment further specifies the configuration of the bellmouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of the portions other than the bellmouth 3F is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3F of the centrifugal fan 1F according to Embodiment 7 will be mainly described with reference to FIG. Note that the bell mouth 3F represents an example in which a general bell mouth is enlarged in the axial direction of the rotating shaft.

A bell mouth 3F of the centrifugal fan 1F has walls forming curved surfaces with different radii of curvature between the upstream end 3a and the downstream end 3b. As shown in FIG. 10, the bell mouth 3F has a first wall portion S31 formed continuously and integrally 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 protrudes 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 with different curvature radii. Here, in the vertical section of the bellmouth 3F, the curvature radius of the first wall portion S31 is defined as a first curvature radius a3, and the curvature radius of the second wall portion S32 is defined as a second curvature radius c3. The bellmouth 3F is configured such that the first wall portion S31 and the second wall portion S32 satisfy the relationship of first curvature radius a3>second curvature radius c3.

[Action and effect of centrifugal blower 1F]
The bell mouth 3F is a general bell mouth enlarged in the axial direction of the rotating shaft. The centrifugal fan 1F has a shape in which the wall portion 3c1 between the upstream end portion 3a and the downstream end portion 3b bulges away from the first outline L1 with reference to the intersection point EC in the vertical cross section of the bellmouth 3F. 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 second wall portion S32 is configured to satisfy the relationship of first curvature radius a3>second curvature radius c3. Therefore, the bell mouth 3F directs the fast airflow flowing into the bell mouth 3F along the second wall portion S32 having the second large curvature radius c3 on the outer peripheral side, followed by the first wall portion S32 having the largest first curvature radius a1. The wall portion S31 naturally deflects the flow in the axial direction of the rotation shaft RS. The bellmouth 3F can suppress the separation of the airflow from the outer edge to the inner edge by having the configuration and action, and can suppress the inflow of turbulent airflow into the impeller 2, thereby suppressing noise. can be done. In addition, the bell mouth 3F suppresses separation of the airflow near the downstream end 3b, which is the innermost diameter, and suppresses the inflow of turbulent airflow into the impeller 2, so that the centrifugal blower 1E takes in air efficiently. be able to.

Embodiment 8.
FIG. 11 is a partially enlarged view of bell mouth 3G of centrifugal fan 1G according to Embodiment 8 of the present invention. Parts having the same configuration as the centrifugal blower 1, etc., shown in FIGS. The centrifugal fan 1G according to the eighth embodiment further specifies the configuration of the bellmouth 3 of the centrifugal fan 1 according to the first embodiment, and the configuration of the portions other than the bellmouth 3G is the same as that of the first embodiment. It is the same as the centrifugal blower 1 according to . Therefore, in the following description, the configuration of the bell mouth 3G of the centrifugal fan 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 imaginary first plane P1 including the ring-shaped downstream end 3b is positioned with respect to the rotation axis RS. It is a vertical plane. Also, the bell mouth 3G has an upstream end 3a arranged on a virtual second plane P2 perpendicular to the rotation axis RS. In other words, the upstream end portion 3a of the bell mouth 3G is formed in a ring shape at the bell mouth 3G, and the virtual second plane P2 including the ring-shaped upstream end portion 3a is positioned 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.

[Action and effect of centrifugal blower 1G]
As described above, the bell mouth 3G has the downstream end 3b arranged on the virtual first plane P1 perpendicular to the rotation axis RS. The bell mouth 3G has an upstream end 3a arranged on a virtual second plane P2 perpendicular to the rotation axis RS. With this configuration, the bell mouth 3G is less susceptible to pressure fluctuations caused by gas sucked into the centrifugal fan 1G. Therefore, when the centrifugal fan 1G is mounted in a unit such as an outdoor unit, it is possible to minimize the influence of pressure loss inside the unit.

Embodiment 9.
FIG. 12 is a side view of centrifugal fan 1H according to Embodiment 9 of the present invention. FIG. 13 is a cross-sectional view of the centrifugal fan 1H of FIG. 12 taken along line BB. FIG. 14 is a CC line cross-sectional view of the centrifugal fan 1H of FIG. 1 to 11. Parts having the same configurations as those of the centrifugal blowers 1 to 1G, etc. of FIGS.

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

That is, while the bellmouth 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 expands in the radial direction and reaches the maximum. The width of the wall portion 3c1 is formed so as to gradually return to the original size while returning to the tongue portion 43 from the enlarged position. The configuration of the bell mouth 3 shown in FIGS. 12, 13 and 14 is an example. In the circumferential direction of the bellmouth 3, the position where the width of the wall portion 3c1 of the air intake portion 3c expands to the maximum in the radial direction is determined, for example, by the relationship with the equipment in which the centrifugal blower 1H is installed. The bell mouth 3 shown in FIGS. 13 and 14 is formed in the same configuration at the suction ports 5 on both sides of the double-suction type centrifugal fan 1. It may be composed of a bell mouth 3 having a

In addition, the width of the wall portion 3c1 of the air intake portion 3c expands in the radial direction in the range in which the bell mouth 3 rotates once in the circumferential direction along the rotation direction R of the impeller 2 from the tongue portion 43. In addition, the radius of curvature on the inner peripheral side of the wall portion 3c1 is formed to gradually increase. The wall portion 3c1 of the air intake portion 3c has the maximum radius of curvature on the inner peripheral side in the range between the tongue portion 43 and the circumferential direction R along the rotation direction R of the impeller 2. have a part. Note that the inner peripheral side is a portion of the wall portion 3c1 of the air intake portion 3c that is closer to the downstream end portion 3b than the upstream end portion 3a.

The air intake portion 3c of the bellmouth 3 has a radial width of the wall portion 3c1 in the circumferential direction between the portion of the wall portion 3c1 having the maximum radius of curvature on the inner peripheral side and returning to the tongue portion 43. As it shrinks, the radius of curvature of the inner peripheral side of the wall portion 3c1 gradually decreases. The air intake portion 3c of the bellmouth 3 gradually increases in the radius of curvature on the inner peripheral side in the circumferential direction from the portion of the wall portion 3c1 having the maximum radius of curvature on the inner peripheral side to the tongue portion 43. It is formed so as to return to the original radius of curvature of the tongue 43 .

That is, in the circumferential direction of the bellmouth 3, the width of the wall portion 3c1 of the air intake portion 3c is increased in the radial direction, and the radius of curvature of the inner peripheral side of the wall portion 3c1 is increased. The width is reduced and the radius of curvature of the inner peripheral side of the wall portion 3c1 is reduced. In addition, 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 peripheral side of the wall portion 3c1 of the air intake portion 3c has the maximum value is determined, for example, by the relationship with the equipment in which the centrifugal blower 1H is installed. . The bell mouth 3 shown in FIGS. 13 and 14 is formed in the same configuration at the suction ports 5 on both sides of the double-suction type centrifugal fan 1. It may be composed of a bell mouth 3 having a

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

[Action and effect of centrifugal blower 1H]
The bell mouth 3 of the centrifugal fan 1H enlarges the size of the radial wall of the air intake portion 3c at a position other than the tongue portion 43 in the circumferential direction, and the radius of curvature of the inner peripheral side of the bell mouth 3 becomes large. is formed as The centrifugal blower 1</b>H has this configuration, thereby reducing separation from the bell mouth 3 of the fast airflow flowing through the bell mouth 3 . Therefore, the centrifugal blower 1H can increase the blowing efficiency and reduce the noise.

Embodiment 10.
[Blower 30]
FIG. 15 is a diagram showing the configuration of blower device 30 according to Embodiment 10 of the present invention. Parts having the same configurations as those of the centrifugal fan 1, etc., shown in FIGS. The blower device 30 according to Embodiment 10 is, for example, a ventilation fan, a desk fan, or the like. Blower device 30 includes any one of centrifugal blower 1 to centrifugal blower 1H according to Embodiments 1 to 9, and case 7 for housing centrifugal blower 1 and the like. In the following description, when referring to the centrifugal fan 1, any one of the centrifugal fan 1 to the centrifugal fan 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 air blower 30 is formed at a position where a suction port 71 and a discharge port 72 face each other. In the blower device 30, for example, either one of the suction port 71 and the discharge port 72 is formed above or below the centrifugal blower 1. Therefore, the suction port 71 and the discharge port 72 are not necessarily formed at positions facing each other. It does not have to be. A partition plate 73 partitions the inside of the case 7 into a space SP1 having a portion in which the suction port 71 is formed and a space SP2 having a portion in which the discharge port 72 is formed. The centrifugal fan 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 air blower 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. - 特許庁The air sucked into the impeller 2 is blown out radially outward of the impeller 2 . The air blown out from the impeller 2 passes through the inside of the fan casing 4 , is blown out from the outlet 42 a of the fan casing 4 , and is blown out from the outlet 72 of the case 7 .

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

Embodiment 11.
[Air conditioner 40]
FIG. 16 is a perspective view of an air conditioner 40 according to Embodiment 11 of the present invention. FIG. 17 is a diagram showing the internal configuration of an air conditioner 40 according to Embodiment 11 of the present invention. FIG. 18 is a cross-sectional view of air conditioner 40 according to Embodiment 11 of the present invention. FIG. 19 is another cross-sectional view of the air conditioner 40 according to Embodiment 11 of the present invention. Parts having the same configuration as the centrifugal blower 1 shown in FIGS. 1 to 15 are denoted by the same reference numerals, and 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. As shown in FIG. The air conditioner 40 according to the eleventh embodiment is positioned facing any one or more of the centrifugal fans 1 to 1H according to the first to ninth embodiments and the outlet 42a of the centrifugal fan 1 and the like. and a heat exchanger 10 arranged in the Further, the air conditioner 40 according to Embodiment 11 includes the case 16 installed in the ceiling space of the room to be air-conditioned. In the following description, when referring to the centrifugal fan 1, any one of the centrifugal fan 1 to the centrifugal fan 1H according to the first to ninth embodiments is used. Further, when the bellmouth 3 is indicated, any one of the bellmouths 3 to 3G described above is used.

(Case 16)
The case 16, as shown in FIG. 16, is formed in 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. There may be. The case 16 has, as one of the side portions 16c, a side portion 16c in which the case outlet 17 is formed. The shape of the case discharge port 17 is formed in a rectangular shape as shown in FIG. The shape of the case outlet 17 is not limited to a rectangular shape, and may be, for example, a circular shape, an oval shape, or other shapes. The case 16 has a side portion 16c formed with a case suction port 18 on the side opposite to the side where the case discharge port 17 is formed. The shape of 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 a rectangular shape, and may be, for example, a circular shape, an oval shape, or other shapes. A filter for removing dust in the air may be arranged at the case suction port 18 .

Two centrifugal fans 1, a fan motor 9, and a heat exchanger 10 are housed inside the case 16. As shown in FIG. A centrifugal fan 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 portion 16a of the case 16. As shown in FIG. The fan motor 9 has an output shaft 6a. The output shaft 6a is arranged 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. As shown in FIG. 17, the air conditioner 40 has two impellers 2 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 blown out from the case discharge port 17 to the space to be air-conditioned. The number of centrifugal fans 1 arranged in the case 16 is not limited to two, and may be one or three or more. In addition, in the centrifugal fan 1 used in the air conditioner 40, the above-described configuration for changing the curvature of the bell mouth 3 can be applied to the entire circumference of the bell mouth 3. When applied to the portion facing the mouth 18, the above effects are exhibited more remarkably. In other words, 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 a partition plate 19, and the internal space of the case 16 is divided into a space SP11 on the suction side of the fan casing 4 and a space SP12 on the blowing side of the fan casing 4. , are separated 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 arranged in the case 16 on the air path of the air discharged by the centrifugal blower 1. As shown in FIG. The heat exchanger 10 adjusts the temperature of the air sucked into the case 16 through the case inlet 18 and blown out through the case outlet 17 into the air-conditioned space. In addition, the heat exchanger 10 can apply the thing of a well-known structure. Further, the case suction port 18 may be formed at a position perpendicular to the axial direction of the rotating shaft RS of the centrifugal blower 1. For example, as shown in FIG. good too. In this case, in the centrifugal fan 1 used in the air conditioner 40, the above-described configuration for changing the curvature of the bell mouth 3 can be applied to the entire circumference of the bell mouth 3. When applied to the portion facing the suction port 18a, the above-described effects are exhibited more remarkably. In other words, 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 rotates by driving the motor 6, the air in the space to be air-conditioned 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. - 特許庁The air sucked into the impeller 2 is blown out radially outward of the impeller 2 . The air blown out from the impeller 2 passes through the inside of the fan casing 4 , is blown out from the outlet 42 a of the fan casing 4 , and is supplied to the heat exchanger 10 . The air supplied to the heat exchanger 10 undergoes heat exchange while passing through the heat exchanger 10, and its 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 Embodiment 11 includes the centrifugal fans 1 to 1H according to Embodiments 1 to 9, noise can be reduced and air can be taken in efficiently.

Embodiment 12.
[Refrigeration cycle device 50]
FIG. 20 is a diagram showing the configuration of a refrigeration cycle apparatus 50 according to Embodiment 12 of the present invention. Centrifugal fans 1 to 1H according to the first to ninth embodiments are used for the indoor unit 200 of the refrigeration cycle apparatus 50 according to the twelfth embodiment. Also, in the following description, the refrigeration cycle device 50 will be described as being used for air conditioning, but the refrigeration cycle device 50 is not limited to being used for air conditioning. The refrigerating cycle device 50 is used, for example, for refrigeration or air conditioning applications such as refrigerators, freezers, vending machines, air conditioners, refrigeration systems, and water heaters.

The refrigerating cycle device 50 according to Embodiment 12 heats or cools the room by transferring heat between the outside air and the indoor air via the refrigerant, thereby performing air conditioning. A refrigeration cycle device 50 according to Embodiment 12 has an outdoor unit 100 and an indoor unit 200 . In the refrigerating cycle device 50, an outdoor unit 100 and an indoor unit 200 are pipe-connected by refrigerant pipes 300 and 400 to form a refrigerant circuit in which 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. 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 switching device 102, the outdoor heat exchanger 103, the expansion valve 105, and the indoor heat exchanger 201 are sequentially connected via refrigerant pipes.

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

The outdoor heat exchanger 103 exchanges heat between refrigerant and 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 the refrigerant. The outdoor heat exchanger 103 functions as a condenser during cooling operation, and performs heat exchange between the refrigerant that has been compressed by the compressor 101 and has flowed in from the flow path switching device 102 and the outdoor air. Condense and liquefy. The outdoor heat exchanger 103 is provided with an outdoor fan 104 in order to increase the efficiency of heat exchange between the refrigerant and the outdoor air. The outdoor fan 104 may be equipped with an inverter device to change the operating frequency of the fan motor to change the rotational speed of the fan. The expansion valve 105 is a throttle device (flow rate control means), 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 degree of opening. For example, if the expansion valve 105 is an electronic expansion valve or the like, the degree of opening is adjusted based on instructions from the control device 110 .

(Indoor unit 200)
The indoor unit 200 has an indoor heat exchanger 201 that exchanges heat between a refrigerant and indoor air, and an indoor fan 202 that adjusts the flow of air with which the indoor heat exchanger 201 exchanges heat. During the heating operation, the indoor heat exchanger 201 functions as a condenser, performs heat exchange between the refrigerant flowing from the refrigerant pipe 300 and the indoor air, condenses the refrigerant and liquefies it. let it flow. The indoor heat exchanger 201 functions as an evaporator during cooling operation, and performs heat exchange between the refrigerant brought to a low pressure state by the expansion valve 105 and indoor air, causing the refrigerant to take heat from the air and evaporate. to vaporize it and flow out to the refrigerant pipe 300 side. Indoor fan 202 is provided so as to face indoor heat exchanger 201 . Any one or more of centrifugal fans 1 to 1H according to Embodiments 1 to 8 is applied to indoor fan 202 . The operating speed of the indoor fan 202 is determined by user settings. An inverter device may be attached to the indoor fan 202 to change the rotational speed of the impeller 2 by changing the operating frequency of the fan motor (not shown).

[Example of operation of refrigeration cycle device 50]
Next, a cooling operation operation will be described as an operation example of the refrigeration cycle device 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 channel switching device 102 . The gas refrigerant that has flowed into the outdoor heat exchanger 103 is condensed by heat exchange with the outside air blown by the outdoor fan 104 , becomes a low-temperature refrigerant, and flows out of the outdoor heat exchanger 103 . The refrigerant that has flowed 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. This 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 fan 202, and becomes a low-temperature, low-pressure gas refrigerant in the indoor heat exchanger. 201. At this time, the indoor air that has been cooled by absorbing heat by the refrigerant becomes conditioned air, and is blown out from the outlet of the indoor unit 200 into the air-conditioned space. The gas refrigerant that has flowed out of the indoor heat exchanger 201 is sucked into the compressor 101 via the flow switching device 102 and compressed again. The above operations are repeated.

Next, a heating operation will be described as an example of the operation of the refrigeration cycle device 50. FIG. 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 switching device 102 . The gas refrigerant that has flowed into the indoor heat exchanger 201 is condensed by heat exchange with the indoor air blown by the indoor fan 202 , becomes a low-temperature refrigerant, and flows out of the indoor heat exchanger 201 . At this time, the indoor air warmed by receiving heat from the gas refrigerant becomes conditioned air and is blown out from the outlet of the indoor unit 200 into the air-conditioned space. The refrigerant flowing out of 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. This 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 fan 104, and becomes a low-temperature, low-pressure gas refrigerant in the outdoor heat exchanger 103. flow out from The gas refrigerant that has flowed out of the outdoor heat exchanger 103 is sucked into the compressor 101 via the flow switching device 102 and compressed again. The above operations are repeated.

Refrigerating cycle device 50 according to Embodiment 12 includes centrifugal blower 1 to centrifugal blower 1H according to Embodiments 1 to 9, so noise can be reduced and air can be taken in efficiently.

The configuration shown in the above embodiment shows an example of the content of the present invention, and it is possible to combine it with another known technology, and one configuration can be used without departing from the scope of the present invention. It is also possible to omit or change the part. For example, in Embodiment 4, the bell mouth 3C has a first wall portion 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. It has S1, a second wall S2, and a third wall S3. The bell mouth 3C has three walls with different curvature radii, but the bell mouth 3C may have four or more walls with different curvature radii. Similarly, in Embodiment 6, the bell mouth 3E has a first wall formed continuously and integrally 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 portion S21, a second wall portion S22, and a third wall portion S23. The bell mouth 3E has three walls with different curvature radii, but the bell mouth 3E may have four or more walls with different curvature radii.

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 portion , 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 portion 3c air intake portion 3c1 wall portion 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 case, 16a upper surface portion, 16b lower surface portion, 16c side surface portion, 17 case discharge port, 18 case suction port, 18a case suction port, 19 partition plate, 30 air blower, 40 air conditioner, 41 scroll portion, 41a start of winding Part 41b Winding end part 42 Discharge part 42a Discharge port 42b Extension plate 42c Diffuser plate 42d First side plate 42e Second side plate 43 Tongue 50 Refrigeration cycle device 71 Suction port 72 Discharge port , 73 Partition plate 100 Outdoor unit 101 Compressor 102 Channel switching device 103 Outdoor heat exchanger 104 Outdoor fan 105 Expansion valve 110 Control device 200 Indoor unit 201 Indoor heat exchanger 202 Indoor fan , 300 refrigerant pipe, 400 refrigerant pipe.

Claims (14)

an impeller having a disk-shaped main plate and a plurality of blades installed on the peripheral edge of the main plate;
a fan casing housing the impeller and having a bell mouth for rectifying gas sucked into the impeller;
with
The bell mouth is
A suction port through which gas flowing into the fan casing passes is formed, and the opening diameter is formed to gradually decrease from an upstream end to a downstream end in the direction of the air flow sucked into the fan casing, and has a vertical cross section. has an air intake portion formed in a curved shape that draws an arc at
In the vertical cross 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 is the end of the short axis. Define a virtual ellipse whose intersection with the axis is located on the outer peripheral side of the downstream end with respect to the rotation axis of the impeller,
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 is
Within a range surrounded by a virtual first tangent line in contact with the upstream end of the ellipse, a virtual second tangent line in contact with the downstream end of the ellipse, and the first outline, the intersection point is the reference As a centrifugal fan, 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
2. A vertical cross-section of said bell mouth, comprising said short axis extending from said upstream end into said fan casing, and said long axis extending from said downstream end in a direction parallel to the radial direction of said impeller. The centrifugal blower described in . The ellipse is
2. A vertical cross section of said bell mouth, comprising said long axis extending from said upstream end into said fan casing and said short axis extending from said downstream end in a direction parallel to the radial direction of said impeller. The centrifugal blower described in . In the vertical section of the bell mouth,
defining a first axial distance as the distance between the upstream end and the intersection of the ellipse;
If the distance between the downstream end and the intersection of the ellipse is defined as a first radial distance,
The bell mouth is
3. The centrifugal fan according to claim 1, wherein the centrifugal blower is formed so as to satisfy the relation of first radial distance>first axial distance. In the vertical section of the bell mouth,
defining a second axial distance as the distance between the upstream end and the intersection of the ellipse;
If the distance between the downstream end and the intersection of the ellipse is defined as a second radial distance,
The bell mouth is
4. The centrifugal fan according to claim 1, wherein the centrifugal blower is formed so as to satisfy the relation of second radial distance<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 the vertical cross section of the bell mouth, and form curved surfaces with different radii of curvature,
When the radius of curvature of the first wall portion is defined as the first radius of curvature, the radius of curvature of the second wall portion is defined as the second radius of curvature, and the radius of curvature of the third wall portion is defined as the third radius of curvature,
The bell mouth is
3. The centrifugal blower according to claim 1, which satisfies the relationship of third radius of curvature>first radius of curvature>second radius of curvature. The bell mouth is
a first wall portion and a second wall portion 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 the vertical cross section of the bell mouth, and form curved surfaces with different radii of curvature,
When the radius of curvature of the first wall portion is defined as the first radius of curvature, and the radius of curvature of the second wall portion is defined as the second radius of curvature,
The bell mouth is
3. The centrifugal fan according to claim 1, wherein the relation of second radius of curvature>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 the vertical cross section of the bell mouth, and form curved surfaces with different radii of curvature,
When the radius of curvature of the first wall portion is defined as the first radius of curvature, the radius of curvature of the second wall portion is defined as the second radius of curvature, and the radius of curvature of the third wall portion is defined as the third radius of curvature,
The bell mouth is
4. The centrifugal fan according to claim 1 or 3, which satisfies the relationship of first radius of curvature>third radius of curvature>second radius of curvature. The bell mouth is
a first wall portion and a second wall portion 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 the vertical cross section of the bell mouth, and form curved surfaces with different radii of curvature,
When the radius of curvature of the first wall portion is defined as the first radius of curvature, and the radius of curvature of the second wall portion is defined as the second radius of curvature,
The bell mouth is
4. The centrifugal blower according to claim 1 or 3, which satisfies the relationship of the first radius of curvature>the second radius of curvature. The bell mouth is
The downstream end is arranged on a virtual first plane perpendicular to the rotation axis of the impeller,
The centrifugal fan according to any one of claims 1 to 9, wherein said upstream end is arranged in a second plane parallel to said first plane. The air intake section is
While making one turn in the circumferential direction along the rotational direction of the impeller from the tongue portion, it is formed so as to expand in the radial direction compared to the position of the tongue portion and to have a larger radius of curvature on the inner peripheral side. 11. The centrifugal fan according to any one of claims 1 to 10, which has a portion that The centrifugal fan according to any one of claims 1 to 11;
a case for accommodating the centrifugal blower;
Blower with. The centrifugal fan according to any one of claims 1 to 11;
a heat exchanger arranged at a position facing the outlet of the centrifugal fan;
An air conditioner with A refrigeration cycle apparatus comprising the centrifugal blower according to any one of claims 1 to 11.

Images