CN112352108B

CN112352108B - Multi-blade blower and air conditioner

Info

Publication number: CN112352108B
Application number: CN201880094504.0A
Authority: CN
Inventors: 迫田健一; 冈本一辉; 菊地仁
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2018-07-03
Filing date: 2018-07-03
Publication date: 2022-07-19
Anticipated expiration: 2038-07-03
Also published as: JP6945739B2; WO2020008519A1; JPWO2020008519A1; CN112352108A

Abstract

In the multiblade blower of the present invention, each blade of the impeller includes a first end and a second end as ends in the rotation axis direction of the impeller. The first end of each of the blades is connected to a main plate of the impeller. The second end of each of the blades faces the suction port. In view of the same blade, the distance between the rotation axis and the inner peripheral end gradually increases from a first intermediate portion, which is a position between the first end and the second end, toward the second end, and the entrance angle gradually increases from the first intermediate portion toward the second end. When the outer peripheral end of the blade is viewed in a radial direction perpendicular to the rotation axis, the outer peripheral end has a substantially linear shape substantially parallel to the rotation axis.

Description

Multi-blade blower and air conditioner

Technical Field

The present invention relates to a sirocco fan having improved blowing performance and an air conditioner including the same.

Background

The sirocco fan includes a fan case having an air inlet and an air outlet, and an impeller housed in the fan case. The sirocco fan pressurizes air sucked into the fan housing from the air inlet by a centrifugal force acting on the air by the rotating impeller, and discharges the air to the outside of the fan housing from the air outlet. Multiblade blowers are also known as sirocco fans.

The sirocco fan is used, for example, as a fan of an air conditioner. In addition, for example, a sirocco fan is used to forcibly circulate air at a place where a static pressure is relatively high. The place where the static pressure is relatively high is, for example, a ventilation duct installed in a factory, a building, or the like, or under the floor of a house. In addition, for example, a sirocco fan is also used as a device for ventilating a room such as a kitchen or a cooking place.

The impeller of the sirocco fan rotates about a rotation shaft. The impeller includes a main plate and a plurality of blades extending in a rotation axis direction from a vicinity of an outer edge portion of the main plate. The plurality of blades are arranged at intervals on a circle centered on the rotation axis. Specifically, each blade includes a first end that is one end in the rotation axis direction and a second end that is the other end in the rotation axis direction. Also, respective first ends of the blades are connected to the main plate. The second ends of the blades face the air inlet of the fan casing.

Therefore, when the impeller rotates about the rotation axis, the air sucked into the fan casing from the air inlet flows into the space surrounded by the plurality of blades and the main plate in the impeller from the second end side which becomes the suction side. The air flowing into the space surrounded by the plurality of blades and the main plate is pressurized outward of the impeller in a substantially radial direction from between adjacent blades by a centrifugal force, and is sent out. Thereafter, the air flowing out of the impeller is discharged to the outside of the fan housing through the exhaust port. The radial direction refers to a direction extending from the rotational axis to a direction perpendicular to the rotational axis.

Here, the flow velocity of air flowing between adjacent blades differs in the direction of the rotation axis. Specifically, the flow velocity of air flowing between adjacent blades is increased on the main plate side and decreased on the second end side which becomes the suction side. In addition, in the case where the air flowing between the adjacent blades flows into the space surrounded by the plurality of blades and the main plate on the second end side which becomes the suction side, the air does not flow perpendicularly to the rotation shaft due to the inertial force acting when the air bends in the radial direction of the impeller when the air flowing into the space surrounded by the plurality of blades and the main plate flows into the space between the adjacent blades. That is, the air flowing between the adjacent blades on the second end side, which is the suction side, flows obliquely toward the main plate side with respect to the direction perpendicular to the rotation axis. In this way, the flow of air flowing between adjacent blades differs in the axial velocity in the direction perpendicular to the rotation axis, in addition to the difference in the flow velocity in the direction of the rotation axis.

On the other hand, the blades of the impeller are generally designed assuming a flow having a uniform velocity profile between adjacent blades. Therefore, the flow assumed in the design differs from the actual flow pattern in the vicinity of the second end which becomes the suction side. Therefore, in the vicinity of the second end, which is the suction side, the pressure loss of the air passing between the adjacent blades is large. Further, due to the different air flows flowing between the adjacent blades, a velocity distribution is generated in the direction of the rotation axis in the air flow flowing out from between the adjacent blades. Further, since a swirling flow is generated inside the fan casing due to the velocity distribution, the air blowing performance of the sirocco fan is deteriorated.

Therefore, in order to suppress the pressure loss of air passing between adjacent blades in the vicinity of the second end serving as the suction side in the conventional sirocco fan, the following sirocco fan has been proposed: the distance from the rotation axis of the impeller to the inner circumferential ends of the blades is changed in the rotation axis direction, and the distance from the rotation axis of the impeller to the outer circumferential ends of the blades is changed in the rotation axis direction (see, for example, patent document 1).

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2014-29149

Disclosure of Invention

Problems to be solved by the invention

The multiblade blower described in patent document 1 changes the distance from the rotation axis to the inner circumferential end of the blade and the distance from the rotation axis to the outer circumferential end of the blade in the rotation axis direction, thereby realizing the adaptation of the blade shape to the flow of air passing between adjacent blades. Thus, the sirocco fan described in patent document 1 suppresses a pressure loss of air passing between adjacent blades. However, the effect of suppressing the pressure loss of the air as a whole of the sirocco fan is small only by changing the distance from the rotation shaft to the inner circumferential end of the blade and the distance from the rotation shaft to the outer circumferential end of the blade in the rotation shaft direction.

This is because, when the outer peripheral end of the same blade is observed, the position of the outer peripheral end is shifted in the rotational direction according to the position in the rotational axis direction in the multiblade blower described in patent document 1. Therefore, in the sirocco fan described in patent document 1, the flow of air flowing out from between adjacent blades is inclined with respect to the direction perpendicular to the rotation axis. On the other hand, the exhaust port of the fan casing is arranged assuming that the flow of air flowing out from between adjacent blades is in a direction perpendicular to the rotation axis. Therefore, in the sirocco fan described in patent document 1, air flowing out from between adjacent blades collides with a wall surface of the fan casing facing in the direction of the rotation axis, and is discharged from the discharge port to the outside of the fan casing. Therefore, in the sirocco fan described in patent document 1, a vortex is generated in the flow of air between the impeller and the exhaust port, and the pressure loss at this portion becomes large.

The present invention has been made to solve the above-described problems, and a first object of the present invention is to provide a sirocco fan capable of reducing the pressure loss of air in the whole sirocco fan and improving the blowing performance as compared with the conventional one. A second object of the present invention is to provide an air conditioner including such a sirocco fan.

Means for solving the problems

The multi-blade blower of the present invention comprises: a fan housing formed with an air intake port and an air exhaust port; and an impeller that is housed in the fan case and that, when rotated about a rotation axis, generates a flow of air that flows into the fan case from the air inlet and flows out to the outside of the fan case from the air outlet, the impeller including: a plurality of blades extending along the rotation axis and arranged on a circle centered on the rotation axis at intervals; and a main plate provided with a plurality of the blades, the blades respectively having: a positive pressure surface that is a surface on a front side in a rotation direction of the impeller; a negative pressure surface which becomes a rear surface in the rotation direction; a first end that is one of the ends in the rotation axis direction; a second end that is the other of the ends in the rotation axis direction; an inner peripheral end which is an end portion in a radial direction extending from the rotational axis in a direction perpendicular to the rotational axis and is an end portion on one side close to the rotational axis; and an outer peripheral end which is the end in the radial direction and is the end apart from the rotation axis, the first end being connected to the main plate, the second end facing the air intake port, wherein, when the same blade is viewed, a distance between the rotation axis and the inner peripheral end gradually increases from a first middle portion which is a position between the first end and the second end toward the second end, an entrance angle gradually increases from the first middle portion toward the second end, an intersection of the outer peripheral end and the positive pressure surface is defined as a first point, an intersection of the outer peripheral end and the negative pressure surface is defined as a second point, an intersection of the outer peripheral end and a center line of the blade is defined as a third point, and a virtual straight line connecting the first point of the first end and the rotation axis is defined as a first straight line, when an imaginary straight line connecting the second point of the first end and the rotation axis is defined as a second straight line, the third point from the first end to the second end is located between the first straight line and the second straight line.

Further, an air conditioning apparatus according to the present invention includes: the multi-blade blower of the invention; and a heat exchanger for heating or cooling the air supplied by the sirocco fan.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention provides a multi-blade blower which can restrain the pressure loss of air passing between adjacent blades and can restrain the generation of vortex in the air flow between an impeller and an exhaust port. Therefore, the sirocco fan according to the present invention can reduce the pressure loss of air in the whole sirocco fan as compared with the conventional one, and can improve the blowing performance.

Drawings

Fig. 1 is a perspective view showing a sirocco fan according to embodiment 1 of the present invention.

Fig. 2 is a plan view showing a state in which the upper panel of the casing is removed in the sirocco fan according to embodiment 1 of the present invention.

Fig. 3 is a perspective view showing an impeller of the sirocco fan according to embodiment 1 of the present invention.

Fig. 4 is a view of an impeller according to embodiment 1 of the present invention, taken along a plane including a rotation axis of the impeller, and viewed in a direction perpendicular to the plane.

Fig. 5 is a view showing a shape of a blade of an impeller according to embodiment 1 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller.

Fig. 6 is a view showing a shape of a blade of an impeller according to embodiment 1 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller.

Fig. 7 is a view showing a shape of a blade of an impeller according to embodiment 1 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller.

Fig. 8 is a perspective view showing an impeller of the sirocco fan according to embodiment 2 of the present invention.

Fig. 9 is a view of an impeller according to embodiment 2 of the present invention, taken along a plane including a rotation axis of the impeller, and viewed in a direction perpendicular to the plane.

Fig. 10 is a view showing a shape of a blade of an impeller according to embodiment 2 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller.

Fig. 11 is a view showing a shape of a blade of an impeller according to embodiment 3 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller.

Fig. 12 is a graph showing the measurement results of the static pressure rise in the sirocco fan 100 according to embodiment 3 of the present invention.

Fig. 13 is a graph showing the measurement results of the air blowing efficiency in the sirocco fan 100 according to embodiment 3 of the present invention.

Fig. 14 is a view of a part of a main plate of an impeller according to embodiment 4 of the present invention as viewed in the direction of the rotation axis.

Fig. 15 is a sectional view showing a main part of a sirocco fan according to embodiment 5 of the present invention.

Fig. 16 is a refrigerant circuit diagram showing an example of an air conditioner according to embodiment 6 of the present invention.

Detailed Description

Embodiment 1.

Fig. 1 is a perspective view showing a sirocco fan according to embodiment 1 of the present invention. Fig. 2 is a plan view showing a state in which the upper panel of the casing is removed in the sirocco fan according to embodiment 1 of the present invention. Fig. 3 is a perspective view showing an impeller of the sirocco fan according to embodiment 1 of the present invention. The circular arc-shaped arrows shown in fig. 2 and 3 indicate the rotation direction of the impeller 30.

The sirocco fan 100 is a device that pressurizes air taken in from the inlet 2 and discharges the air from the outlet 4 to forcibly flow the air. The sirocco fan 100 includes: a fan case 1 having an air inlet 2 and an air outlet 4 formed therein, and an impeller 30 housed in the fan case 1.

The impeller 30 is a component that: the air is forcibly discharged outward of the impeller 30 in a substantially radial direction by centrifugal force generated by rotation of the impeller about the rotary shaft 31 by the rotation drive of the drive device 70 such as a motor. The radial direction refers to a direction extending from the rotation axis 31 in a direction perpendicular to the rotation axis 31. That is, the impeller 30 rotates about the rotation shaft 31, and generates a flow of air that flows into the fan casing 1 through the air inlet 2 and flows out to the outside of the fan casing 1 through the air outlet 4. The impeller 30 includes a main plate 40 and a plurality of blades 50.

The main plate 40 is a circular plate rotatably provided around the rotating shaft 31. The main plate 40 is provided with a plurality of blades 50. Specifically, the motherboard 40 includes a first surface 41 and a second surface 42 that is a rear surface of the first surface 41. In embodiment 1, a plurality of blades 50 are provided on the first surface 41 of the main plate 40. The plurality of blades 50 are provided, for example, near the outer periphery of the main plate 40.

A plurality of blades 50 extend from the main plate 40 along the rotation axis 31. The plurality of blades 50 are arranged at intervals on a circle centered on the rotation shaft 31. Specifically, each of the blades 50 includes a first end 51 which is one end in the direction of the rotation shaft 31 and a second end 52 which is the other end in the direction of the rotation shaft 31. The first ends 51 of the blades 50 are connected to the first surface 41 of the main plate 40. The second ends 52 of the blades 50 face the inlet 2 of the fan casing 1. That is, each of the vanes 50 extends substantially perpendicularly to the first surface 41 of the main plate 40 in a direction from the first surface 41 of the main plate 40 toward the air inlet 2. Each of the blades 50 is parallel to the radial direction or inclined at a predetermined angle with respect to the radial direction when viewed along the direction of the rotation shaft 31. The direction of the rotation shaft 31 refers to a direction in which the rotation shaft 31 extends.

The second ends 52 of the vanes 50, i.e., the ends on the inlet 2 side, are connected by the connection portion 45. The coupling portion 45 is a series of annular members having a diameter capable of connecting the second ends 52 of the plurality of vanes 50. By this connection, the positional relationship of the second ends 52 of the plurality of blades 50 is maintained, and the plurality of blades 50 are reinforced. The coupling portion 45 may be a ring-shaped plate member having a width capable of covering the second end 52 of each vane 50, or may be a ring-shaped member coupling the outer peripheral sides of the vanes 50. With such a configuration, the impeller 30 rotates, and thus air sucked into the space surrounded by the main plate 40 and the plurality of blades 50 is sent radially outward through the space between adjacent blades 50.

The fan housing 1 is a scroll-type fan housing. The fan casing 1 includes a main body 10 that houses the impeller 30 and a duct portion 20 connected to the main body 10.

The body portion 10 is a hollow cylindrical member having a substantially columnar space formed therein, for example. The main body portion 10 substantially surrounds the entire impeller 30. The shape of the space formed inside the fan casing 1 is not limited to a cylindrical shape, and may be, for example, a cylindrical shape having a polygonal cross section. The fan case 1 includes a lower panel 11, an upper panel 12, and a peripheral wall 13 as members constituting wall surfaces. The upper panel 12 has an air inlet 2 formed in a region facing the second ends 52 of the plurality of blades 50 so that air can flow between the impeller 30 and the outside of the fan casing 1. Further, the inlet 2 is provided with a bell mouth 3. The bell mouth 3 has a cross section gradually decreasing from the outside of the fan casing 1 toward the inside thereof so that air flows smoothly through the air inlet 2 and its vicinity. The center of the inlet port 2 substantially coincides with the rotation shaft 31 of the impeller 30.

The lower panel 11 and the upper panel 12 are disposed opposite to each other in the direction of the rotation axis 31. That is, the upper plate 12 is provided on the suction side of the impeller 30, that is, on the second end 52 side, and the lower plate 11 is provided on the main plate 40 side of the impeller 30. The peripheral wall 13 connects the outer edge of the lower surface plate 11 to the outer edge of the upper surface plate 12, and extends to the outer periphery of the impeller 30. Further, a portion of the side surface of the body 10 has a portion where the peripheral wall 13 is not provided. This portion serves as a main body exhaust port 14 through which air exhausted from the main body 10 to the outside of the main body 10 passes.

As shown in fig. 2, the gap between the peripheral wall 13 of the body 10 and the outer peripheral end of the impeller 30 is enlarged at a predetermined ratio from a tongue portion 26 described later in the rotation direction of the impeller 30. This allows the air sent from the impeller 30 to flow smoothly through the gap. Further, since the flow passage area of the air gradually increases from the tongue portion 26 to the body portion exhaust port 14, the static pressure of the air can be efficiently increased as the air sent from the impeller 30 flows through the gap.

The duct portion 20 is a hollow tube having a substantially rectangular cross section perpendicular to the flow direction of air. The duct portion 20 forms a flow path for guiding the air flowing out from the body portion air outlet 14 of the body portion 10 to the outside of the fan case 1. An opening portion at one end of the duct portion 20 serves as an inlet 25 through which air flowing into the duct portion 20 passes. The opening at the other end of duct portion 20 serves as an exhaust port 4 through which air flowing out of duct portion 20 passes, in other words, through which air discharged from fan casing 1 passes. That is, the peripheral edge of the inlet 25 of the duct portion 20 is connected to the peripheral edge of the body exhaust port 14 of the body 10.

The duct section 20 includes an extension plate 21, a diffusion plate 22, a lower surface plate 23, and an upper surface plate 24 as members constituting wall surfaces. The extension plate 21 is smoothly connected to an end portion on the downstream side in the air flow direction among end portions of the peripheral wall 13 of the main body 10 constituting the peripheral edge of the main body exhaust port 14. The diffuser 22 is connected to an upstream end of the peripheral wall 13 of the main body 10, which constitutes the periphery of the main body exhaust port 14, in the air flow direction. The diffuser plate 22 is disposed at a predetermined angle to the extension plate 21 so that the cross-sectional area of the flow path gradually increases toward the flow direction of the air in the duct section 20. The lower plate 23 and the upper plate 24 connect the outer edge of the extension plate 21 and the outer edge of the diffusion plate 22, respectively, to form a substantially rectangular flow path. The lower panel 23 is connected to an end of the lower panel 11 of the body 10 that forms the periphery of the body exhaust port 14. The upper panel 24 is connected to an end of the upper panel 12 of the main body 10 that constitutes the peripheral edge of the main body exhaust port 14.

The diffuser 22 and the peripheral wall 13 of the main body 10 are joined smoothly at a predetermined radius of curvature from the lower panel 11 to the upper panel 12 of the fan housing 1 to form a tongue 26. The air flow flowing into the main body 10 from the inlet 2 through the impeller 30 is collected by the main body 10, and the tongue 26 serves as a branch point when the collected air flows into the duct 20. That is, the static pressure of the air flowing into the duct portion 20 increases while the air passes through the main body portion 10, and the air becomes higher in pressure than the vicinity of the tongue portion 26 in the main body portion 10. The tongue portion 26 has a function of partitioning the flow of air flowing again into the main body portion 10 from the duct portion 20 by the pressure difference. Further, since the tongue portion 26 is formed to have a predetermined radius of curvature, when air flows into the duct portion 20 from the main body portion 10, even if the air collides with the tongue portion 26, turbulence generated in the tongue portion 26 can be reduced. Therefore, deterioration of air blowing performance and increase of noise can be suppressed. In embodiment 1, the radius of curvature of the tongue portion 26 is constant in the direction of the rotation axis 31, but the radius of curvature of the tongue portion 26 does not need to be constant in the direction of the rotation axis 31. For example, the radius of curvature of the tongue portion 26 on the inlet port 2 side, i.e., the upper panel 12 side, may be larger than the radius of curvature of the tongue portion 26 on the lower panel 11 side.

Next, the detailed shape of the blade 50 of the impeller 30 according to embodiment 1 will be described with reference to fig. 3 and fig. 4 to 7 described later. Since each of the blades 50 has the same shape, fig. 4 to 7 show the shape of one blade 50.

Fig. 4 is a view of an impeller according to embodiment 1 of the present invention, taken along a plane including a rotation axis of the impeller, and viewed in a direction perpendicular to the plane. Fig. 5 to 7 are views showing the shape of the impeller blade according to embodiment 1 of the present invention when viewed in the direction of the rotation axis of the impeller. In other words, fig. 5 to 7 are views of the shape of the blade 50 when viewed in a cross section perpendicular to the rotation shaft 31. Here, fig. 5 shows the shape of the blade 50 at the position of the first end 51 which is the end on the main plate 40 side. Fig. 6 shows the shape of the vane 50 at the position of the second end 52 which is the end on the suction port 2 side. In addition, fig. 7 shows the shape of the blade 50 at the position of the first end 51 and the shape of the blade 50 at the position of the second end 52. In fig. 7, the shape of the blade 50 at the position of the second end 52 is indicated by a broken line in order to easily distinguish the shape of the blade 50 at the position of the first end 51 from the shape of the blade 50 at the position of the second end 52. The hollow arrows shown in fig. 5 to 7 indicate the rotation direction of the impeller 30.

The vane 50 includes a positive pressure surface 55, a negative pressure surface 56, an inner peripheral end 53, and an outer peripheral end 54. The positive pressure surface 55 is a surface that is located on the front side in the rotation direction of the impeller 30. The negative pressure surface 56 is a surface that is on the rear side in the rotation direction of the impeller 30. The inner peripheral end 53 is an end in a radial direction extending from the rotation shaft 31 in a direction perpendicular to the rotation shaft 31, and is an end close to the rotation shaft 31. The outer peripheral end 54 is a radial end and is an end away from the rotation shaft 31.

As shown in fig. 4, the length of the blade 50 in the direction of the rotation shaft 31 is a length L1. That is, the length in the direction of the rotation shaft 31 from the first end 51 to the second end 52 is a length L1. Further, the distance between the rotary shaft 31 and the outer peripheral end 54 of the blade 50 is the same distance Do from the first end 51 to the second end 52. Further, the distance between the rotary shaft 31 and the inner peripheral end 53 of the vane 50 is equal to the distance Di0 from the first end 51 to the first middle portion 57. The distance between the rotary shaft 31 and the inner peripheral end 53 of the blade 50 gradually increases from the first intermediate portion 57 toward the second end 52, and becomes a distance Di1 at the position of the second end 52. The first middle portion 57 is located between the first end 51 and the second end 52, and is located at a distance L0 from the first end 51 in embodiment 1. The length L0 is, for example, approximately half the length of the length L1.

Here, the "same" in embodiment 1 does not have a strictly identical meaning, but has a substantially identical meaning. For example, the distance between the rotational shaft 31 and the outer circumferential end 54 of the blade 50 is designed to be the same distance Do from the first end 51 to the second end 52. However, in the actual impeller 30, the distance between the rotation shaft 31 and the outer peripheral end 54 of the blade 50 does not become exactly the same distance Do from the first end 51 to the second end 52, and variations occur due to machining errors and the like. In embodiment 1, even when a slight variation occurs due to such a machining error or the like, the distance between the rotary shaft 31 and the outer peripheral end 54 of the blade 50 is referred to as the same distance Do from the first end 51 to the second end 52.

As shown in fig. 5 to 7, in a cross section perpendicular to the rotation shaft 31, the center line 60 of the blade 50 has a shape connecting arcs having a plurality of radii of curvature. The center line 60 is a line connecting a point having the same distance from the positive pressure surface 55 and the negative pressure surface 56 from the inner peripheral end 53 to the outer peripheral end 54.

The inlet angle of the blade 50 is the same inlet angle α 0 from the first end 51 to the first intermediate portion 57. The inlet angle of the vane 50 gradually increases from the first intermediate portion 57 toward the second end 52, and becomes the inlet angle α 1 at the position of the second end 52. Namely, α 1> α 0. Note that the inlet angle of the vane 50 is defined as follows. First, in a cross section perpendicular to the rotation axis 31, an arc passing through an intersection of the center line 60 and the inner peripheral end 53 is drawn around the rotation axis 31. The arc is defined as an inner circumference arc. A tangent to the inner circumference side arc at the intersection of the center line 60 and the inner circumference end 53 is drawn so as to extend in the direction opposite to the rotation direction of the impeller 30. A tangent to the center line 60 at the intersection of the center line 60 and the inner peripheral end 53 is drawn so as to extend in the direction opposite to the rotation direction of the impeller 30. When the tangent to the inner circumference side arc and the tangent to the center line 60 are drawn in this manner, the angle formed by the tangent to the inner circumference side arc and the tangent to the center line 60 becomes the inlet angle of the blade 50.

In addition, the exit angle of the blade 50 is the same exit angle β from the first end 51 to the second end 52. Note that the exit angle of the blade 50 is defined as follows. First, in a cross section perpendicular to the rotation axis 31, an arc passing through an intersection of the center line 60 and the outer peripheral end 54 is drawn with the rotation axis 31 as a center. The arc is defined as an outer circumference arc. A tangent to the outer circumferential arc at the intersection of the center line 60 and the outer circumferential end 54 is drawn so as to extend in the direction opposite to the rotation direction of the impeller 30. In addition, a tangent to the center line 60 at the intersection of the center line 60 and the outer peripheral end 54 is drawn so as to extend in the rotation direction of the impeller 30. When the tangent to the outer-peripheral arc and the tangent to the center line 60 are drawn in this manner, the angle formed by the tangent to the outer-peripheral arc and the tangent to the center line 60 is the exit angle of the blade 50.

The outer peripheral ends 54 of the blades 50 are arranged at the following positions. In detail, in a cross section perpendicular to the rotation axis 31, the first point 61, the second point 62, the third point 63, the first straight line 65, and the second straight line 66 are defined as follows. The intersection of the outer peripheral end 54 and the positive pressure surface 55 is defined as a first point 61. The intersection of the outer peripheral end 54 and the negative pressure surface 56 is defined as a second point 62. The intersection of the outer peripheral end 54 and the center line 60 of the blade 50 is defined as a third point 63. A virtual straight line connecting the first point 61 of the first end 51 and the rotation shaft 31 is defined as a first straight line 65. A virtual straight line connecting the second point 62 of the first end 51 and the rotation shaft 31 is defined as a second straight line 66. In the case defined as such, the third point 63 from the first end 51 to the second end 52 is located between the first straight line 65 and the second straight line 66.

By disposing the outer peripheral end 54 of the blade 50 from the first end 51 to the second end 52 in this manner, it is understood that, when the outer peripheral end 54 of the blade 50 is viewed in the radial direction, the outer peripheral end 54 has a substantially linear shape substantially parallel to the rotation shaft 31, for example, when viewed from the region a shown in fig. 3.

Next, the flow of air during operation of the sirocco fan 100 according to embodiment 1 will be described.

When the impeller 30 rotates, air located inside the impeller 30 is sent out in a substantially radial direction outward of the impeller 30 by a centrifugal force generated by the rotation of the impeller 30. Further, air flows into the impeller 30 through the intake port 2. The air sent out to the outside of the impeller 30 flows along the peripheral wall 13 of the main body 10 of the fan casing 1 in the rotation direction of the impeller 30 in the main body 10. The sectional area between the impeller 30 and the peripheral wall 13 increases in the rotational direction of the impeller 30. Therefore, the dynamic pressure of the air flowing in the main body 10 is converted into the static pressure, and the static pressure is gradually increased in the main body 10. The air having the increased static pressure flows into the duct portion 20 through the body exhaust port 14 and the inlet 25 of the duct portion 20, and is then discharged from the exhaust port 4.

As described above, the air sucked into the impeller 30 from the inlet port 2 in the direction of the rotation shaft 31 changes the flow direction from the direction of the rotation shaft 31 to the radial direction by the centrifugal force generated by the rotation of the impeller 30. However, the air sucked into the impeller 30 does not abruptly change the flow direction at the second end 52 side of the impeller 30, which is the inlet port 2 side, due to the inertia of the air flowing in the direction of the rotary shaft 31. Therefore, the flow on the second end 52 side of the impeller 30 becomes a flow inclined in the direction of the main plate 40 with respect to the direction perpendicular to the rotation shaft 31. In addition, the flow rate of air passing through the second end 52 side of the impeller 30 is also smaller than that of the main plate 40 side. That is, on the second end 52 side of the impeller 30, the velocity of the air at the inner peripheral end 53 of the vane 50 is small. Therefore, on the second end 52 side of the impeller 30, it is difficult for air to flow between the adjacent blades 50.

However, in the vane 50 according to embodiment 1, the distance between the rotary shaft 31 and the inner peripheral end 53 of the vane 50 gradually increases from the first intermediate portion 57 toward the second end 52 on the inlet 2 side. Therefore, the inner peripheral end 53 of the vane 50 on the second end 52 side can be aligned with the flow inclined in the direction of the main plate 40. Therefore, on the second end 52 side, air easily flows between the adjacent blades 50.

In embodiment 1, the inlet angle of the vane 50 gradually increases from the first intermediate portion 57 toward the second end 52 on the inlet port 2 side. For example, as can be seen from fig. 7, when the inlet angle of the blade 50 is small, the air that attempts to flow radially between adjacent blades 50 collides with the negative pressure surface 56 of the blade 50. On the other hand, by increasing the inlet angle of the vanes 50, the vicinity of the inner peripheral end 53 is close to parallel with respect to the air that is about to flow radially between the adjacent vanes 50. Therefore, by increasing the inlet angle of the blade 50, the air that attempts to flow between adjacent blades 50 can be suppressed from colliding with the suction surface 56 of the blade 50. Therefore, by gradually increasing the inlet angle of the vane 50 from the first middle portion 57 toward the second end 52 on the inlet port 2 side, the air more easily flows between the adjacent vanes 50 on the second end 52 side. Therefore, the impeller 30 according to embodiment 1 can reduce the pressure loss generated in the vicinity of the second ends 52 of the blades 50.

When the flow of air sent from between the adjacent blades 50 into the main body 10 is oblique to the direction perpendicular to the rotation shaft 31, the air sent into the main body 10 flows into the main body 10 while colliding with the lower surface plate 11 and the upper surface plate 12. When such flowing air flows into the duct portion 20, the air flows through the duct portion 20 while colliding with the lower panel 23 and the upper panel 24. Therefore, if the flow of air sent from between the adjacent blades 50 into the main body 10 is inclined with respect to the direction perpendicular to the rotation axis 31, a vortex is generated in the flow of air between the impeller 30 and the exhaust port 4 in the fan housing 1, and the pressure loss at this portion becomes large.

On the other hand, the outer peripheral end 54 of the vane 50 of embodiment 1 has a substantially linear shape substantially parallel to the rotation shaft 31. Therefore, the flow of air sent out into the main body 10 from between the adjacent blades 50 is inclined to a direction perpendicular to the rotation shaft 31 to a small degree. Therefore, in the sirocco fan 100 according to embodiment 1, the flow of air between the impeller 30 and the exhaust port 4 in the fan casing 1 can be suppressed from colliding with the lower panel 11, the upper panel 12, the lower panel 23, and the upper panel 24. Therefore, in the sirocco fan 100 according to embodiment 1, it is possible to suppress the generation of a vortex flow in the flow of air between the impeller 30 and the exhaust port 4 in the fan casing 1, and to reduce the pressure loss at that location.

As described above, in the sirocco fan 100 according to embodiment 1, when the same blade 50 is viewed, the distance between the rotary shaft 31 and the inner peripheral end 53 gradually increases from the first middle portion 57 toward the second end 52, and the inlet angle gradually increases from the first middle portion 57 toward the second end 52. In the sirocco fan 100 according to embodiment 1, when the same blade 50 is viewed, a third point 63 from the first end 51 to the second end 52 is located between the first straight line 65 and the second straight line 66 in a cross section perpendicular to the rotary shaft 31.

Therefore, the sirocco fan 100 according to embodiment 1 can suppress the pressure loss of the air passing between the adjacent blades 50 and also suppress the generation of a vortex flow in the flow of the air between the impeller 30 and the exhaust port 4. Therefore, the sirocco fan 100 according to embodiment 1 can reduce the pressure loss of the air in the entire sirocco fan 100 as compared with the conventional one, and can improve the air blowing performance. Furthermore, the sirocco fan 100 according to embodiment 1 can reduce the pressure loss of the air in the whole sirocco fan 100 as compared with the conventional one, and therefore, the effect of reducing noise can also be obtained.

The length L0 from the first end 51, which indicates the position of the first midway portion 57 of the blade 50, is preferably in the range of 0.5. ltoreq.L 0/L1. ltoreq.0.7. Specifically, the inventors studied the change in the flow velocity of the air flowing between the adjacent blades 50 in the direction of the rotary shaft 31 using a conventional impeller in which the distance between the rotary shaft 31 and the inner peripheral ends 53 of the blades 50 and the inlet angle are not changed from the first end 51 to the second end 52. As a result, it was confirmed that the flow velocity of the air gradually decreased from the substantially central position of the blade 50 in the direction of the rotation shaft 31 toward the second end 52. At a position where the flow velocity of the air is not decreased, it is preferable that the distance between the rotary shaft 31 and the inner circumferential end 53 of the vane 50 and the inlet angle are not changed. On the other hand, at a position where the flow velocity of the air is reduced, it is preferable that the distance between the rotary shaft 31 and the inner circumferential ends 53 of the blades 50 and the inlet angle be changed as described above so that the air easily flows between the adjacent blades 50. Therefore, the length L0 from the first end 51, which indicates the position of the first midway portion 57 of the blade 50, is preferably in the range of 0.5. ltoreq.L 0/L1. ltoreq.0.7.

The distance between the rotary shaft 31 and the inner peripheral end 53 of the vane 50 and the change in the inlet angle between the first intermediate portion 57 and the second end 52 may be linearly changed or may be changed in a quadratic function manner. As a result of the experiments by the inventors, the effect of suppressing the pressure loss of the air passing between the adjacent blades 50 is large in the range of α 1 to α 0 of 15 to 35 degrees. Therefore, α 1- α 0 is preferably in the range of 15 to 35 degrees. As a result of the experiments by the inventors, the effect of suppressing the pressure loss of the air passing between the adjacent blades 50 is large in the range of Di1/Di0 to 1.02 to 1.10. Therefore, Di1/Di0 is preferably in the range of 1.02 to 1.10.

Embodiment 2.

The distance between the rotary shaft 31 and the outer circumferential end 54 of the blade 50 may be different from the first end 51 to the second end 52 as follows. In embodiment 2, items not specifically described are the same as those in embodiment 1, and the same functions and configurations are described using the same reference numerals.

Fig. 8 is a perspective view showing an impeller of the sirocco fan according to embodiment 2 of the present invention. Fig. 9 is a view of an impeller according to embodiment 2 of the present invention, taken along a plane including a rotation axis of the impeller, and viewed in a direction perpendicular to the plane. Fig. 10 is a view showing a shape of the impeller according to embodiment 2 of the present invention when the blades of the impeller are viewed in the direction of the rotation axis of the impeller. In other words, fig. 10 is a view of the shape of the blade 50 as viewed in a cross section perpendicular to the rotation shaft 31. Here, fig. 10 shows the shape of the blade 50 at the position of the first end 51 and the shape of the blade 50 at the position of the second end 52. In fig. 10, the shape of the blade 50 at the position of the second end 52 is indicated by a broken line in order to easily distinguish the shape of the blade 50 at the position of the first end 51 from the shape of the blade 50 at the position of the second end 52. The circular arc-shaped arrows shown in fig. 8 and the hollow arrows shown in fig. 10 indicate the rotation direction of the impeller 30.

The distance between the rotary shaft 31 and the outer peripheral end 54 of the blade 50 is the same distance Do0 from the first end 51 to the second middle portion 58. The distance between the rotary shaft 31 and the outer peripheral end 54 of the blade 50 gradually increases from the second intermediate portion 58 toward the second end 52, and becomes the distance Do1 at the position of the second end 52. Here, the second middle portion 58 is located between the first end 51 and the second end 52, and is located at a distance L0 from the first end 51 in embodiment 2. Length L0 is, for example, approximately half the length of length L1. The length from the first end 51 to the first middle-way portion 57 may be different from the length from the first end 51 to the second middle-way portion 58.

The exit angle of the blade 50 is the same exit angle β 0 from the first end 51 to the second intermediate portion 58. The exit angle of the blade 50 gradually decreases from the second intermediate portion 58 toward the second end 52, and becomes an exit angle β 1 at the position of the second end 52. Namely, β 1< β 0. The change in the exit angle between the second midway portion 58 and the second end 52 may be changed linearly or may be changed in a quadratic function manner.

In embodiment 2, the third point 63 from the first end 51 to the second end 52 is also located between the first straight line 65 and the second straight line 66. By disposing the outer peripheral end 54 of the blade 50 from the first end 51 to the second end 52 in this manner, it is possible to see that the outer peripheral end 54 has a substantially linear shape substantially parallel to the rotation shaft 31 when the outer peripheral end 54 of the blade 50 is viewed in the radial direction, for example, as seen from a region B shown in fig. 8.

Next, the flow of air during operation of the sirocco fan 100 according to embodiment 2 will be described.

When the impeller 30 rotates, air located inside the impeller 30 is sent out substantially radially outward of the impeller 30 by a centrifugal force generated by the rotation of the impeller 30. Further, air flows into the impeller 30 through the intake port 2. In this case, the centrifugal force generated increases as the outer diameter of the impeller 30 increases. In the impeller 30 of embodiment 2, the outer diameter of the impeller 30 is larger on the second end 52 side on the inlet 2 side where the flow velocity of air is low and air easily flows obliquely with respect to the rotary shaft 31. Therefore, the centrifugal force generated in the air sucked into the impeller 30 is larger toward the second end 52 on the suction port 2 side.

Accordingly, the air passing through the second end 52 of the vane 50 on the inlet 2 side flows more outward in the radial direction of the impeller 30 due to a strong centrifugal force. Further, the air flow is pulled outward in the radial direction of the impeller 30 by a strong centrifugal force, and thus the air flow inclined with respect to the direction perpendicular to the rotation shaft 31 is more likely to flow in the direction perpendicular to the rotation shaft 31. That is, the difference between the flow velocity of the air flowing out from the first end 51 side to the outside of the impeller 30 and the flow velocity of the air flowing out from the second end 52 side to the outside of the impeller 30 is small, and the velocity distribution in the direction of the rotary shaft 31 is relaxed.

By reducing the velocity distribution in the direction of the rotation shaft 31, the flow of the air sent from the impeller 30 is further reduced in inclination with respect to the direction perpendicular to the rotation shaft 31, as compared with embodiment 1. Therefore, in the sirocco fan 100 according to embodiment 2, the flow of air between the impeller 30 and the exhaust port 4 in the fan housing 1 can be further suppressed from colliding with the lower panel 11, the upper panel 12, the lower panel 23, and the upper panel 24, as compared with embodiment 1. Therefore, in the sirocco fan 100 according to embodiment 2, as compared with embodiment 1, the generation of a vortex flow in the flow of air between the impeller 30 and the exhaust port 4 in the fan casing 1 can be further suppressed, and the pressure loss at that location can be further reduced. That is, the air blowing performance of the sirocco fan 100 according to embodiment 2 is further improved.

In order to further obtain the above-described effect of increasing the air passing on the second end 52 side of the vane 50 on the intake port 2 side, in embodiment 2, the outlet angle of the vane 50 gradually decreases from the second intermediate portion 58 toward the second end 52. Therefore, the air flowing out from the second end 52 side to the outside of the impeller 30 flows out more easily to the outside of the impeller 30 than the air flowing out from the first end 51 side to the outside of the impeller 30. This can further relax the velocity distribution in the direction of the rotation shaft 31, and further improve the air blowing performance.

As described in embodiment 1, the length L0 from the first end 51 indicating the position of the second intermediate portion 58 of the blade 50 is preferably in the range of 0.5L 0/L1 0.7. As a result of the experiments by the inventors, the effect of facilitating the flow of air through the second end 52 side is large in the range of β 0 to β 1 from 5 degrees to 15 degrees. Therefore, β 0 to β 1 are preferably in the range of 5 degrees to 15 degrees. As a result of the experiments conducted by the inventors, the effect of facilitating the flow of air through the second end 52 side is large in the range of Do1/Do0 equal to 1.04 to 1.12. Therefore, Do1/Do0 is preferably in the range of 1.04 to 1.12.

Embodiment 3.

The inner peripheral end 53 of the vane 50 may be arranged from the first end 51 to the second end 52 as follows. In embodiment 3, items not specifically described are the same as those in embodiment 1 or embodiment 2, and the same functions and configurations are described using the same reference numerals. In embodiment 3, an example in which the arrangement of the inner peripheral ends 53 of the blades 50 is modified with respect to the impeller 30 shown in embodiment 2 will be described.

Fig. 11 is a view showing a shape of a blade of an impeller according to embodiment 3 of the present invention when the blade is viewed in a direction of a rotation axis of the impeller. In other words, fig. 11 is a view of the shape of the blade 50 as viewed in a cross section perpendicular to the rotation shaft 31. Here, fig. 11 shows the shape of the blade 50 at the position of the first end 51 and the shape of the blade 50 at the position of the second end 52. Note that the hollow arrow shown in fig. 11 indicates the rotation direction of the impeller 30.

In embodiment 3, when the same blade 50 is viewed, the inner peripheral end 53 of the blade 50 gradually retreats from the first intermediate portion 57 toward the second end 52 in the direction opposite to the rotation direction of the blade 50. In embodiment 3, when the same blade 50 is viewed in the direction of the rotation shaft 31, the inner peripheral end 53 overlaps the cross section of the blade 50 at the position of the first end 51 from the first end 51 to the second end 52. In order to arrange the inner peripheral end 53 in this manner, in embodiment 3, specifically, the vane 50 is formed in the following shape.

As described above, the center line 60 of the blade 50 has a shape connecting arcs having a plurality of radii of curvature. In embodiment 3, from the first end 51 to the second end 52, an arc passing through the inner peripheral end 53 among the plurality of arcs of the center line 60 is set to an arc having the same center and the same radius of curvature. With such a configuration, when the distance between the rotary shaft 31 and the inner peripheral end 53 of the blade 50 is gradually increased from the first intermediate portion 57 toward the second end 52, the inner peripheral end 53 is separated from the rotary shaft 31 along the arc passing through the inner peripheral end 53 among the arcs of the center line 60. Thereby, the inner peripheral end 53 of the vane 50 gradually retreats from the first intermediate portion 57 toward the second end 52 in the opposite direction to the rotation direction of the vane 50. When the same blade 50 is viewed in the direction of the rotation shaft 31, the inner peripheral end 53 overlaps the cross section of the blade 50 at the position of the first end 51 from the first end 51 to the second end 52.

By arranging the inner peripheral end 53 in this manner, the vicinity of the inner peripheral end 53 is close to parallel with the air that attempts to flow radially between the adjacent blades 50. Therefore, the air that attempts to flow between the adjacent blades 50 can be suppressed from colliding with the negative pressure surface 56 of the blade 50. Therefore, the air on the second end 52 side easily flows between the adjacent blades 50, and the pressure loss generated in the vicinity of the second end 52 of the blade 50 can be reduced.

Further, by arranging the inner peripheral end 53 in this manner, when the same blade 50 is viewed in the direction of the rotation shaft 31, the inner peripheral end 53 overlaps the cross section of the blade 50 at the position of the first end 51 from the first end 51 to the second end 52, and therefore, when the impeller 30 is manufactured by injection molding, the vicinity of the inner peripheral end 53 of the blade 50 can be molded by a mold that moves in the direction of the rotation shaft 31. Therefore, by arranging the inner peripheral end 53 in this manner, the impeller 30 can be easily manufactured when the impeller 30 is manufactured by injection molding.

The effect of the sirocco fan 100 according to embodiment 3 was verified through experiments.

Fig. 12 is a graph showing the measurement results of the static pressure rise in the sirocco fan 100 according to embodiment 3 of the present invention. Fig. 13 is a graph showing the measurement results of the air blowing efficiency in the sirocco fan 100 according to embodiment 3 of the present invention. The open circles in fig. 12 and 13 show the measurement results of the sirocco fan 100 according to embodiment 3. In addition, black circles in fig. 12 and 13 indicate measurement results of the conventional sirocco fan. As a conventional sirocco fan, a sirocco fan is used in which each blade 50 is changed to a blade having a cross-sectional shape perpendicular to the rotation shaft 31 from the first end 51 to the second end 52, as compared with the sirocco fan 100 of embodiment 3.

As is apparent from fig. 12 and 13, the sirocco fan 100 according to embodiment 3 of the present invention has higher static pressure and higher air blowing efficiency than the conventional sirocco fan, and improvement in air blowing performance is confirmed.

Embodiment 4.

In the sirocco fan 100 described in embodiments 1 to 3, the main plate 40 of the impeller 30 is notched as follows, whereby the impeller 30 can be easily manufactured. In embodiment 4, items not particularly described are the same as those in any of embodiments 1 to 3, and the same functions and configurations are described using the same reference numerals. In embodiment 4, an example in which the main plate 40 of the impeller 30 shown in embodiment 3 is notched will be described.

Fig. 14 is a view of a part of a main plate of an impeller according to embodiment 4 of the present invention as viewed in the direction of the rotation axis. In fig. 14, the shape of the blade 50 at the positions of the first end 51 and the second end 52 is also described. In fig. 14, the shape of the blade 50 at the position of the second end 52 is indicated by a broken line in order to easily distinguish the shape of the blade 50 at the position of the first end 51 from the shape of the blade 50 at the position of the second end 52. The hollow arrows shown in fig. 14 indicate the rotation direction of the impeller 30.

A projection range 43, which is a range of the main plate 40 of the impeller 30 in which the blades 50 are projected toward the main plate 40 in the direction of the rotation shaft 31, is notched. The hatched range in fig. 14 is the projection range 43. In other words, the main plate 40 of the impeller 30 is notched in the range shown by hatching in fig. 14. Note that the main board 40 may be configured to be notched in a range larger than the projection range 43 as long as the entire projection range 43 is included in the notched range.

By making the main plate 40 notched as in embodiment 4, when the impeller 30 is manufactured by injection molding, the portion of the mold that molds the suction surface 56 side of the blade 50 can be inserted from the notched portion of the main plate 40. Therefore, by making a notch in the main plate 40 as in embodiment 4, the impeller 30 can be manufactured by a pair of molds that move in the direction of the rotation shaft 31. Therefore, by making the main plate 40 with the notch as in embodiment 4, the impeller 30 can be easily manufactured as compared with the case where the main plate 40 is not made with the notch.

In the projection range 43, in other words, the notched portion of the main plate 40 is the negative pressure surface side of the blade 50. The flow on the negative pressure surface side of the blade 50 has a lower pressure than the flow on the positive pressure surface side of the blade 50. Therefore, even if the main plate 40 is notched as in embodiment 4, the reduction in the air blowing performance of the sirocco fan 100 is suppressed to a small extent.

Embodiment 5.

In the impeller 30 shown in embodiments 1 to 4, the plurality of blades 50 are connected only to the first surface 41 of the main plate 40. That is, the sirocco fan 100 described in embodiments 1 to 4 is a so-called single suction type sirocco fan. Without being limited to this, a plurality of blades 50 may be connected to both the first surface 41 and the second surface 42 of the main plate 40 shown in embodiments 1 to 4. That is, the sirocco fan 100 may be configured as a so-called double suction type sirocco fan. In embodiment 5, items not specifically described are the same as those in any of embodiments 1 to 4, and the same functions and configurations are described using the same reference numerals.

Fig. 15 is a sectional view showing a main part of a sirocco fan according to embodiment 5 of the present invention. Fig. 15 is a view of the sirocco fan 100 taken along a plane including the rotation shaft 31, and shows a part of the impeller 30 and a part of the fan housing 1 in the vicinity of the impeller 30.

In the impeller 30 according to embodiment 5, the plurality of blades 50 are connected to both the first surface 41 and the second surface 42 of the main plate 40. Therefore, the air inlet 2 is formed in the lower surface plate 11 of the fan casing 1 at a position facing the second ends 52 of the plurality of blades 50 provided on the second surface 42. That is, the sirocco fan 100 according to embodiment 5 is a so-called double suction type sirocco fan.

Even in the case where the sirocco fan 100 is a double suction type sirocco fan as in embodiment 5, the effects shown in embodiments 1 to 4 can be obtained. A plurality of conventional blades may be provided on one of the first surface 41 and the second surface 42. The effects described in embodiments 1 to 4 can be obtained by providing the plurality of vanes 50 described in embodiments 1 to 4 on the other of the first surface 41 and the second surface 42.

Embodiment 6.

In embodiment 6, an example of an air conditioning apparatus including the sirocco fan 100 described in any one of embodiments 1 to 5 will be described. In embodiment 6, items not specifically described are the same as those in any of embodiments 1 to 5, and the same functions and configurations are described using the same reference numerals.

Fig. 16 is a refrigerant circuit diagram showing an example of an air conditioner according to embodiment 6 of the present invention. The air conditioner 200 includes a compressor 210, a four-way valve 220, an outdoor heat exchanger 230, an expansion valve 240, and an indoor heat exchanger 250. The air conditioning apparatus 200 includes the sirocco fan 100 described in any one of embodiments 1 to 5 as a fan for supplying air to the indoor heat exchanger 250. The air conditioner 200 includes, for example, a propeller-type blower 260 as a blower for supplying air to the outdoor heat exchanger 230. The sirocco fan 100 described in any one of embodiments 1 to 5 may be used as the fan for supplying air to the outdoor heat exchanger 230. When the sirocco fan 100 described in any one of embodiments 1 to 5 is used as the fan for supplying air to the outdoor heat exchanger 230, the fan for supplying air to the indoor heat exchanger 250 may be a fan other than the sirocco fan 100. That is, the air conditioning apparatus 200 according to embodiment 6 includes the sirocco fan 100 described in any one of embodiments 1 to 5 in at least one of the fan that supplies air to the outdoor heat exchanger 230 and the fan that supplies air to the indoor heat exchanger 250.

The compressor 210 compresses and discharges a sucked refrigerant. The four-way valve 220 is a valve that switches the flow of the refrigerant between cooling operation and heating operation, for example. The outdoor heat exchanger 230 exchanges heat between the refrigerant and outdoor air supplied by the blower 260. The outdoor heat exchanger 230 functions as an evaporator during the heating operation, and evaporates and gasifies the refrigerant. The outdoor heat exchanger 230 functions as a condenser during the cooling operation, and condenses and liquefies the refrigerant.

The expansion valve 240 is, for example, an expansion device or the like, and decompresses and expands the refrigerant. The indoor heat exchanger 250 exchanges heat between the refrigerant and the air supplied by the sirocco fan 100. The air heat-exchanged in the indoor heat exchanger 250 is supplied to the air-conditioned space. Specifically, the indoor heat exchanger 250 functions as a condenser during the heating operation, and condenses and liquefies the refrigerant. In other words, during the heating operation, the indoor heat exchanger 250 heats the air supplied by the sirocco fan 100. The indoor heat exchanger 250 functions as an evaporator during the cooling operation, and evaporates and gasifies the refrigerant. In other words, during the cooling operation, the indoor heat exchanger 250 cools the air supplied by the sirocco fan 100.

As described above, the air conditioner 200 according to embodiment 6 includes the sirocco fan 100 described in any one of embodiments 1 to 5 and a heat exchanger that heats or cools the air supplied by the sirocco fan 100. The air conditioner 200 according to embodiment 6 includes the sirocco fan 100 having an improved blowing performance compared to the conventional one, and thus has improved power efficiency.

Description of the reference numerals

1 fan casing, 2 air inlet, 3 bell mouth, 4 air outlet, 10 main body, 11 lower panel, 12 upper panel, 13 peripheral wall, 14 main body air outlet, 20 duct portion, 21 extension setting plate, 22 diffusion plate, 23 lower panel, 24 upper panel, 25 inlet, 26 tongue portion, 30 impeller, 31 rotation shaft, 40 main plate, 41 first surface, 42 second surface, 43 projection range, 45 connection portion, 50 blades, 51 first end, 52 second end, 53 inner peripheral end, 54 outer peripheral end, 55 positive pressure surface, 56 negative pressure surface, 57 first middle portion, 58 second middle portion, 60 center line, 61 first point, 62 second point, 63 third point, 65 first line, 66 second line, 70 driving device, 100 multi-blade blower, 200 air conditioner, 210, 220 four-way valve, 230 outdoor heat exchanger, 240 expansion valve, 250 indoor heat exchanger, 260 blower.

Claims

1. A multiblade blower in which, in a blower,

the multi-blade blower includes:

a fan housing formed with an air suction port and an air discharge port; and

an impeller housed in the fan case and configured to rotate about a rotation axis to generate a flow of air flowing into the fan case from the air inlet and flowing out of the fan case from the air outlet,

the impeller is provided with:

a plurality of blades extending along the rotation axis and arranged on a circle centered on the rotation axis at intervals; and

a main plate provided with a plurality of the blades,

the blades are respectively provided with:

a positive pressure surface which is a surface on the front side in the rotation direction of the impeller;

a negative pressure surface that becomes a surface on the rear side in the rotation direction;

a first end that is one of the ends in the rotation axis direction;

a second end that is the other of the ends in the rotation axis direction;

an inner peripheral end which is an end portion in a radial direction extending from the rotational axis in a direction perpendicular to the rotational axis and is an end portion on one side close to the rotational axis; and

an outer peripheral end which is an end in the radial direction and is an end away from the rotation axis,

the first end is connected with the main board, the second end is opposite to the air suction port,

when the same said blade is observed,

a distance between the rotation axis and the inner peripheral end gradually increases from a first middle portion as a position between the first end and the second end toward the second end,

the distance between the rotation axis and the inner peripheral end is the same from the first end to the first midway portion,

the entrance angle gradually becomes larger from the first midway portion toward the second end,

the entry angle is the same from the first end to the first mid-way portion,

a distance between the rotation axis and the outer peripheral end gradually increases from a second halfway portion that is a position between the first end and the second end toward the second end,

the distance between the rotation axis and the outer peripheral end is the same from the first end to the second midway portion,

the outlet angle gradually decreases from the second midway portion toward the second end,

in a cross section perpendicular to the rotation axis, when an intersection of the outer peripheral end and the positive pressure surface is defined as a first point, an intersection of the outer peripheral end and the negative pressure surface is defined as a second point, an intersection of the outer peripheral end and a center line of the vane is defined as a third point, an imaginary straight line connecting the first point of the first end and the rotation axis is defined as a first straight line, and an imaginary straight line connecting the second point of the first end and the rotation axis is defined as a second straight line, the third point from the first end to the second end is located between the first straight line and the second straight line, and the outer peripheral end has a straight line shape substantially parallel to the rotation axis when viewed in the radial direction.

2. The multi-vane blower of claim 1,

when the same said blade is observed,

the inner peripheral end gradually recedes from the first midway portion toward the second end in a direction opposite to the rotation direction of the blade,

when the same blade is viewed in the direction of the rotation axis,

from the first end to the second end, the inner circumferential end overlaps a cross-section of the blade at the location of the first end.

3. The multi-blade blower of claim 1 or 2,

the main plate has a cutout in a projection range that is a range of the main plate in which the blade is projected in the rotation axis direction.

4. The multi-vane blower of claim 1 or 2,

the main board has a first surface and a second surface that is a back surface of the first surface,

a plurality of the blades are connected to both the first surface and the second surface,

in the fan case, the air inlet is formed at a position facing the second ends of the plurality of blades provided on the first surface of the main plate and at a position facing the second ends of the plurality of blades provided on the second surface of the main plate.

5. The multi-vane blower of claim 3,

6. An air conditioner, comprising:

the sirocco fan according to any one of claims 1 to 5; and

a heat exchanger that heats or cools air supplied from the sirocco fan.