JP7760897B2 - blower - Google Patents

Description

The present invention relates to a blower.

The blower described in Patent Document 1 has a centrifugal fan placed inside a case equipped with a bell mouth that forms an air intake port. When the fan rotates, air is drawn in from inside the bell mouth, flows from the leading edge of the blades through the flow passages between the blades, and is blown out from an air outlet on the trailing edge of the blades. This blower has a shape in which the inner circumferential surfaces of the fan shroud and the bell mouth are essentially step-free, allowing air to be drawn smoothly from the bell mouth into the fan.

Patent No. 6634929

However, with the configuration described in Patent Document 1, when the pressure on the fan's air outlet side becomes greater than the pressure on the fan's air inlet side, the air blown out from the fan's air outlet flows back toward the fan's air inlet side through the gap between the shroud and the case. If the volume of this backflowing air increases, there is a concern that the blowing efficiency of the fan will decrease.

In addition, the air that flows back from the fan's air outlet to its air inlet contains a velocity component in the direction of the fan's rotation, so if this backflowing air containing this velocity component intersects with the main flow coming in from the air inlet and is sucked into the leading edge of the fan, it may generate noise.

In consideration of the above, the present invention aims to provide a blower that can improve blowing efficiency and reduce noise by reducing the amount of air that flows back from the fan's air outlet side to its air inlet side.

To achieve the above object, according to the invention of claim 1, a blower includes a case (10), a fan (20), a nozzle (60), and a flow path partition member (70). The case has a bell mouth (11) that forms an inlet (2) for drawing air. The fan has a main plate (21) rotatably disposed around an axis (CL) inside the case, a plurality of blades (22) arranged around the axis and connected to the main plate, and a shroud (30) connected to portions (23) of the plurality of blades on the opposite side of the main plate. The nozzle is formed in a cylindrical shape and is provided in a region radially inside the bell mouth. The flow path partition members are provided intermittently in the circumferential direction between the bell mouth and the nozzle, and divide the space between the nozzle and the bell mouth into a plurality of partition flow paths (73) through which air flows. The flow path partition members are configured with an increased number of members and a thicker thickness so as to increase the pressure loss of air passing through the partition flow paths compared to the number of members and thickness required to support the nozzle.
According to a fourth aspect of the present invention, a blower includes a case (10), a fan (20), a nozzle (60), and a flow path partition member (70). The case has a bell mouth (11) that forms an air inlet (2) for drawing in air. The fan has a main plate (21) rotatably mounted around an axis (CL) inside the case, a plurality of blades (22) arranged around the axis and connected to the main plate, and a shroud (30) connected to portions (23) of the plurality of blades on the opposite side of the main plate. The nozzle is formed in a cylindrical shape and is provided in a region radially inside the bell mouth. The flow path partition members are provided intermittently in the circumferential direction between the bell mouth and the nozzle, dividing the space between the nozzle and the bell mouth into a plurality of partitioned flow paths (73) through which air flows. The flow path partition members are provided in a net-like configuration between the nozzle and the bell mouth so as to increase the pressure loss of air flowing between the nozzle and the bell mouth.

According to this design, when the fan rotates, air drawn in from inside the nozzle flows from the leading edge of the blade through the passages between the blades and is blown out from the air outlet on the trailing edge of the blade. At this time, if pressure loss in the passage downstream of the blower is large and the difference between the pressure on the fan's outlet side and the pressure on the suction port side increases as the fan's rotation speed increases, the volume of air flowing back from the fan's air outlet side to the suction port side through the gaps between the shroud and the case (hereinafter referred to as "backflow air") increases. If the blower does not include a passage partition member, the backflow air may increase in speed and volume as it crosses the end of the nozzle opposite the main plate and flows inside the nozzle. In contrast, the invention of claim 1 uses passage partition members intermittently installed circumferentially between the bellmouth and the nozzle to divide the space between the nozzle and the bellmouth into multiple partition passages, thereby increasing the pressure loss of the backflow air passing through these multiple partition passages. Therefore, according to the invention of claim 1, the wind speed and volume of backflow air that flows inside the nozzle across the end of the nozzle opposite the main plate can be reduced, improving the blowing efficiency of the blower.

Furthermore, research by the inventors has revealed that backflow air that crosses the end of the nozzle opposite the main plate and flows inside the nozzle has a large circumferential velocity distribution, and this backflow air intersects with the main flow coming in from the suction port and flows toward the leading edge of the blade, increasing noise. In response to this, the invention of claim 1 makes it possible to reduce the circumferential velocity distribution of the backflow air by using a flow path partition member to increase the pressure loss of the backflow air passing through multiple partition flow paths. Therefore, the invention of claim 1 makes it possible to reduce blower noise.

According to the invention of claim 7, the blower comprises a case (10), a fan (20), a nozzle (60), and multiple flow path partition members (70). The case has a bell mouth (11) that forms an air inlet (2) for drawing in air. The fan has a main plate (21) rotatably mounted around an axis (CL) inside the case, multiple blades (22) arranged around the axis and connected to the main plate, and a shroud (30) connected to portions (23) of the multiple blades on the opposite side of the main plate. The nozzle is cylindrical and is located in a region radially inward of the bell mouth. Multiple flow path partition members are located between the bell mouth and the nozzle and divide the space between the nozzle and the bell mouth into multiple partition flow paths (73) through which air flows. This blower has areas where the spacing between the multiple flow path partition members is narrow and areas where the spacing between the multiple flow path partition members is wide, so that the wind speed of air flowing back through the space formed between the bell mouth and the nozzle from the air outlet side of the fan through the multiple partition flow paths to the suction port inside the nozzle is uniform.

By arranging the narrower spacing between multiple flow path partition members in locations where the backflow air speed is higher, it is possible to make the backflow air speed uniform in the circumferential direction between the nozzle and the bell mouth. Therefore, according to the invention of claim 7, the multiple flow path partition members reduce the circumferential speed distribution of the backflow air across the nozzles, thereby reducing blower noise.

Furthermore, in the invention of claim 7, by arranging the areas where the spacing between multiple flow path partition members is narrow in areas where the wind speed of the backflow air is high and increasing the pressure loss of the backflow air flowing through those areas, the volume of the backflow air can be reduced and the blowing efficiency of the blower can be improved.

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

1 is a cross-sectional view of a blower according to a first embodiment, taken along an imaginary plane including an axis. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 3 is an enlarged view of part III in FIG. 1, showing the air flow in face mode. FIG. 3 is an enlarged view of part III in FIG. 1, showing the air flow in a foot mode or a defroster mode. FIG. 10 is a view of a portion of a blower according to a second embodiment, the portion corresponding to FIG. 2 . FIG. 10 is a view of a portion of a blower according to a third embodiment, the portion corresponding to FIG. 2 . FIG. 10 is a view of a portion of a blower according to a fourth embodiment, the portion corresponding to FIG. 2 . FIG. 10 is a view of a portion of a blower according to a fifth embodiment, the portion corresponding to FIG. 2 . FIG. 3 is a view corresponding to FIG. 2 in a blower of a comparative example, showing the air flow in a foot mode or a defroster mode. FIG. 4 is a view corresponding to FIG. 3 in a blower of a comparative example, showing the air flow in face mode. FIG. 4 is a diagram of a portion of the blower of the comparative example corresponding to FIG. 3, showing the flow of air in a foot mode or a defroster mode. FIG. 13 is a cross-sectional view of a blower according to a sixth embodiment, taken along an imaginary plane including an axis. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. FIG. 16 is an enlarged view of a portion XVI in FIG. 12, showing the air flow in the face mode. FIG. 16 is an enlarged view of a portion XVI in FIG. 12, showing the air flow in the foot mode or the defroster mode.

Embodiments of the present invention will be described below with reference to the drawings. Note that, in the following embodiments, identical or equivalent parts will be designated by the same reference numerals, and their description will be omitted. Furthermore, the shapes of the components of the blower 1 shown in the drawings are shown schematically to make the description easier to understand, and are not intended to limit the present invention.

(First embodiment)
A first embodiment will be described with reference to the drawings. A blower 1 of the first embodiment is a centrifugal blower used in, for example, an air conditioner for a vehicle.

<Configuration of blower 1>
As shown in Figures 1 and 2, blower 1 includes a case 10, a fan 20, a drive unit 50, a nozzle 60, and a flow path partition member 70. Note that in Figure 2, the fan 20 and drive unit 50 are omitted for clarity. This also applies to Figures 5 to 9 and 13, which will be referred to in the embodiments and comparative examples described below.

In the following description, the axial center CL of the fan 20 will sometimes be referred to simply as the "axial center CL." The axial center CL coincides with the center of rotation of the fan 20. In addition, the air intake 2 side of the blower 1 will be referred to as "one side in the axial direction," and the side opposite the air intake 2 of the blower 1 will be referred to as "the other side in the axial direction." Hereinafter, the air intake 2 will be referred to simply as the intake 2.

The case 10 is a component that forms at least a portion of the air passage of a vehicle air conditioner. Although not shown, the air passage of a vehicle air conditioner typically includes an air cooling device such as an evaporator, an air heating device such as a heater core or electric heater, and multiple flow path switching doors. Therefore, the pressure loss of the air flowing through the air passage of a vehicle air conditioner can change depending on the air conditioning mode.

The case 10 has a bell mouth 11 on the upstream side of the fan 20, which forms the intake port 2 for drawing in air. The bell mouth 11 has a curved shape with an inner diameter that gradually decreases from one side in the axial direction to the other. Furthermore, when viewed in a cross section obtained by cutting the bell mouth 11 along a plane that includes the axial center CL of the fan 20 (hereinafter referred to as the "longitudinal cross section"), the radially inner surface of the bell mouth 11 is formed in a roughly arc shape.

The case 10 has a front wall 12 that extends radially outward from a portion on one axial side of the bell mouth 11. The front wall 12 is formed in a planar shape that is approximately perpendicular to the axial center CL of the fan 20. The front wall 12 may also be formed so as to be inclined with respect to the axial center CL of the fan 20. The case 10 has an upstream case 13 that extends radially outward from the portion of the front wall 12 on one axial side.

The case 10 also has a cylindrical case portion 14 that extends cylindrically from the portion on the other axial side of the bell mouth 11 further toward the other axial side, and a case annular portion 15 that extends radially outward from the portion of the case cylindrical portion 14 on the other axial side. The case 10 also has a downstream case 16 that extends from the radially outer portion of the case annular portion 15 toward the other axial side. Each portion of the case 10 may be composed of multiple members, or may be molded integrally.

The case cylindrical portion 14 is provided in a region radially outward of the shroud cylindrical portion 32 of the fan 20 (described later), with a predetermined gap between them. The case annular portion 15 is provided in a region on one side of the shroud annular portion 31 of the fan 20 (described later) in the axial direction, with a predetermined gap between them. The case cylindrical portion 14 and the shroud cylindrical portion 32 are provided approximately parallel, and the case annular portion 15 and the shroud annular portion 31 are also provided approximately parallel.

The fan 20 is a centrifugal fan (specifically, a turbofan) that is rotatably mounted inside the case 10. The fan 20 has a main plate 21, multiple blades 22, a shroud annular portion 31, and a shroud tubular portion 32. In the description of the first embodiment, the shroud annular portion 31 and the shroud tubular portion 32 are sometimes collectively referred to as the shroud 30. The fan 20 is a closed fan in which the main plate 21, multiple blades 22, and shroud 30 are integrally formed. The fan 20 is integrally formed, for example, by resin injection molding.

The main plate 21 is formed in a roughly disk shape and is positioned inside the case 10. The main plate 21 slopes radially outward from the center toward the other side of the axial direction. In other words, the main plate 21 has a shape that convexly extends from the outer edge toward the center toward the suction port 2. A shaft 51 extending from the drive unit 50 is fixed to the center of the main plate 21. This allows the main plate 21 to rotate around the axis inside the case 10.

The plurality of blades 22 are arranged at predetermined intervals around the axis between the main plate 21 and the shroud 30. Each of the plurality of blades 22 has a portion 23 on one axial side (i.e., the portion 23 on the opposite side of the main plate) connected to the shroud 30, and a portion 24 on the other axial side connected to the main plate 21. This forms a flow path between adjacent blades 22 between the shroud 30 and the main plate 21. In the following description, this flow path will be referred to as an inter-blade flow path 25. When the fan 20 rotates, air drawn in through the suction port 2 passes through the inter-blade flow path 25 from the leading edge 26 side of the blade 22, and is blown out from an air outlet 28 formed on the trailing edge 27 side of the blade 22.
Although not shown, the blades 22 extend rearward in the rotation direction of the fan 20 from a leading edge 26 to a trailing edge 27. That is, the fan 20 of the first embodiment is a turbofan.

The leading edge 26 of the blade 22 has an end 29 on one axial side that connects to the shroud tubular portion 32. The leading edge 26 of the blade 22 is inclined radially inward from the end 29 on one axial side to the end 291 on the other axial side, and the end 291 on the other axial side connects to the main plate 21 radially inward of the innermost diameter of the nozzle 60. In the following description, the leading edge 26 of the blade 22 may also be referred to as the blade leading edge 26.

In the first embodiment, the shroud 30 has a cylindrical shroud tubular portion 32 formed on the suction port 2 side and an annular shroud annular portion 31 extending radially outward from the other axially-located portion of the shroud tubular portion 32. The shroud annular portion 31 is an annular portion connected to one axially-located portion 23 of the plurality of blades 22 (i.e., the portion 23 of the plurality of blades 22 opposite the main plate). The shroud tubular portion 32 is a cylindrical portion of the shroud annular portion 31 extending from a radially inner portion toward the opposite main plate. The shroud annular portion 31 and the shroud tubular portion 32 are formed continuously. The shroud annular portion 31 has a smoothly curved surface shape that is convex toward the inter-blade passage 25 in a longitudinal cross-sectional view. This prevents the air flowing through the inter-blade passage 25 from separating from the surface of the shroud 30 facing the inter-blade passage 25, and instead flows along the surface of the shroud 30 facing the inter-blade passage 25.

The drive unit 50 is an electric motor that outputs torque when energized. The shaft 51 protruding from the drive unit 50 is fixed to the main plate 21 of the fan 20. When the electric motor serving as the drive unit 50 is energized, the torque output by the drive unit 50 causes the shaft 51 and the fan 20 to rotate around their axis.

The nozzle 60 is cylindrical and extends from the radially inner region of the bell mouth 11 to the radially inner region of the shroud tubular portion 32. The nozzle 60 is fixed to the case 10 by a flow path partition member 70 (described below) and functions as a stator vane.

The end 61 of the nozzle 60 on the anti-main board side (i.e., one end of the nozzle 60 in the axial direction) protrudes further toward the anti-main board side (i.e., one side in the axial direction) than the front wall 12 of the case 10. The nozzle 60 is shaped so that it expands radially outward from the center toward the anti-main board end 61. The nozzle 60 is also shaped so that its outer diameter gradually decreases from the anti-main board end 61 toward the main board 21 end 62 (i.e., from one side in the axial direction to the other).

In addition, when viewed in vertical cross section, the nozzle 60 has a thickness that gradually decreases from the center toward the end 62 on the main plate 21 side (i.e., the other end in the axial direction) compared to the thickness from the end 61 on the side opposite the main plate (i.e., one end in the axial direction) to the center. The nozzle 60 has a so-called blade shape, with the axial length along its radially inner surface being longer than the axial length along its radially outer surface.

As shown in Figures 1 and 2, a flow path partition member 70 is provided between the bell mouth 11 and the nozzle 60. The flow path partition member 70 has a radially inner portion connected to the bell mouth 11 and a radially outer portion connected to the nozzle 60. The flow path partition members 70 are provided intermittently in the circumferential direction between the bell mouth 11 and the nozzle 60, and divide the space between the nozzle 60 and the bell mouth 11 into multiple partition flow paths 73 through which air flows.

It is preferable that the number of flow path partition members 70 be at least twice as many (e.g., eight or more) as the number required to support the nozzles 60 (e.g., two to four) so that the pressure loss of air passing through the multiple partition flow paths 73 increases. It is also preferable that the number of flow path partition members 70 be configured to be eight or more (e.g., eight or more) so that the axial and circumferential air flow can be reduced compared to the air flow in each partition flow path 73 when the number required to support the nozzles 60 (e.g., two to four) is used.

The blower 1 of the first embodiment shown in Figure 2 has 20 flow path partition members 70. Increasing the number of flow path partition members 70 in this way makes it possible to increase the pressure loss of air passing through each partition flow path 73. It also makes it possible to reduce the axial and circumferential air flow in each partition flow path 73 and rectify the air flow in each partition flow path 73. However, the number of flow path partition members 70 is not limited to the number shown in Figure 2 and can be set appropriately depending on the performance, specifications, etc. required of the blower 1.

Furthermore, in order to increase the pressure loss of air passing through the multiple partitioned flow paths 73, it is preferable that each flow path partition member 70 has a large thickness when viewed from the axial direction. However, taking into consideration the prevention of distortion during resin injection molding, the thickness of each flow path partition member 70 is preferably approximately 1.5 to 3.0 mm, and even more preferably 2.0 to 2.5 mm.

Increasing the number of flow path partition members 70 and increasing the thickness of the flow path partition members 70 when viewed from the axial direction narrows the distance between adjacent flow path partition members 70 (i.e., the flow path cross-sectional area when viewed from the axial direction of each partition flow path 73). This makes it possible to increase the pressure loss of air passing through the partition flow paths 73. Furthermore, increasing the number of flow path partition members 70 and increasing the axial length of the flow path partition members 70 increases the axial distance of each partition flow path 73. This increases the pressure loss of air passing through each partition flow path 73 and improves the rectification effect of air flowing axially and circumferentially through each partition flow path 73.

In the first embodiment, the flow path partition members 70 are provided radially between the nozzle 60 and the bell mouth 11. The flow path partition members 70 are also provided around the entire circumference between the bell mouth 11 and the nozzle 60. The flow path partition members 70 are also provided at uniform intervals in the circumferential direction between the bell mouth 11 and the nozzle 60. Note that uniform intervals in the circumferential direction refer to uniformity within a range that includes manufacturing tolerances. In this specification, for example, if the difference in cross-sectional area between the multiple partition flow paths 73 formed by the flow path partition members 70 is within 5%, this is considered to be within the uniform range.

The end 71 of the flow path partition member 70 on the side opposite the main plate is located closer to the main plate 21 than the end 61 of the nozzle 60 on the side opposite the main plate. On the other hand, the end 72 of the flow path partition member 70 on the side opposite the main plate is located closer to the main plate than the end 62 of the nozzle 60 on the side opposite the main plate 21. Therefore, the flow path partition member 70 does not obstruct the mainstream flow that is drawn into the fan 20 from the flow path upstream of the nozzle 60 through the suction port 2 radially inside the nozzle 60.

As shown in Figures 3 and 4, in the following description of the first embodiment, the space between the nozzle 60 and the bellmouth 11 on one side of the partition passage 73 in the axial direction is referred to as the first passage 81. Furthermore, the space between the nozzle 60 and the case cylindrical portion 14 on the other side of the partition passage 73 in the axial direction is referred to as the second passage 82. Furthermore, the space between the nozzle 60 and the shroud cylindrical portion 32 is referred to as the third passage 83. Furthermore, the space between the shroud 30 (specifically, the shroud cylindrical portion 32 and the shroud annular portion 31) and the inner wall of the case 10 (specifically, the case cylindrical portion 14 and the case annular portion 15) is referred to as the gap passage 84.

<Operation of blower 1>
Next, the flow of air when the blower 1 of this embodiment is operated will be described.

<Face Mode>
First, the air flow when the air conditioner is in face mode and the blower 1 is operating will be described with reference to Figure 3. Generally, when the air conditioner is in face mode, the pressure loss in the flow path downstream of the blower 1 is smaller than in foot mode or defroster mode.

When the fan 20 rotates, air is drawn into the inter-blade flow passage 25 of the fan 20 from the radially inner region of the nozzle 60, as shown by arrow F1 in Figure 3. The air flow indicated by arrow F1 is called the main flow. Part of this main flow flows along the radially inner surface of the nozzle 60.

At the same time, as shown by arrows F2 and F3, air drawn into the fan 20 along the front wall 12 of the case 10 collides with the radially outer surface of the nozzle 60, flows along that surface through the first flow path 81 → partition flow path 73 → second flow path 82 → third flow path 83, and is drawn into the inter-blade flow path 25 from the blade leading edge 26 side.

Furthermore, when the fan 20 rotates, the pressure at the air outlet 28 of the fan 20 becomes higher than the pressure on the inlet 2 side of the fan 20. Therefore, as shown by arrows F4 and F5, air flows in the gap passage 84, flowing backward from the air outlet 28 toward the inlet 2. Note that the air flowing backward through the gap passage 84 contains a velocity component in the rotational direction of the fan 20. The air flowing through the gap passage 84, shown by arrows F4 and F5, and the air flowing in from the first passage 81, shown by arrow F2, merge in the second passage 82, then flow through the third passage 83, shown by arrow F3, and are sucked into the inter-blade passage 25 together with the main flow from the blade leading edge 26 side.

Here, the pressure of the air flowing along the radially outer surface of the nozzle 60 is higher than the pressure of the main air flowing into the fan 20 along the radially inner surface of the nozzle 60. Therefore, the pressure difference between the pressure in the first flow path 81, partition flow path 73, and second flow path 82 and the pressure on the air outlet 28 side of the fan 20 is reduced, and the amount of air flowing back through the gap flow path 84 from the air outlet 28 side of the fan 20 can be reduced.

In addition, when the air flowing through the first flow path 81 and the air flowing backward through the gap flow path 84 meet in the second flow path 82, the velocity component of the combined air in the rotational direction of the fan 20 becomes smaller. Therefore, the angle of intersection between the air blown out from the third flow path 83 toward the blade leading edge 26 and the main flow becomes smaller, thereby reducing noise.

<Foot mode or defroster mode>
Next, the air flow when the air conditioner is in the foot mode or defroster mode and the blower 1 is operated will be described with reference to FIG.

As the fan 20 rotates, the main flow is drawn into the inter-blade passage 25 from the leading edge 26 of the fan 20 along the radially inner surface of the nozzle 60, as indicated by arrow F1 in FIG. 4. Generally, when an air conditioning system is in foot mode or defroster mode, the pressure loss in the passage downstream of the blower 1 is greater than in face mode. Therefore, as the rotation speed of the fan 20 increases, the difference in pressure between the air outlet 28 and the air inlet 2 of the fan 20 becomes greater than the pressure difference in face mode. As a result, when the speed and volume of air flowing back through the gap passage 84 increase, the backflow air attempts to flow from the second passage 82 through the partition passage 73 and the first passage 81, straddling the end 61 of the nozzle 60 on the anti-main-plate side, and into the interior of the nozzle 60, as indicated by dashed arrow F6 in FIG. 4. In contrast, in the first embodiment, the space between the nozzle 60 and the bell mouth 11 is separated into multiple partitioned flow paths 73 by a flow path partition member 70, which increases the pressure loss of the backflow air passing through these partitioned flow paths 73, reducing the wind speed and volume of the backflow air.

Furthermore, research by the inventors has revealed that the backflow air that attempts to flow inside the nozzle 60 across the end 61 of the nozzle 60 on the side opposite the main plate has a large circumferential wind speed distribution. In contrast, in the first embodiment, the space between the nozzle 60 and the bellmouth 11 is partitioned into multiple partition flow paths 73 by the flow path partition member 70, which increases the pressure loss of the backflow air passing through these partition flow paths 73 and reduces the circumferential wind speed distribution of the backflow air.

<Comparative Example>
Here, for comparison with the blower 1 of the first embodiment described above, a comparative blower 100 will be described with reference to Figures 9 to 11. Note that this comparative blower 100 was created by the applicant and is not a prior art.

As shown in Figure 9, the blower 100 of the comparative example has the necessary number of ribs 700 (for example, four) between the bell mouth 11 and the nozzle 60 to support the nozzle 60. The effect of these ribs 700 as flow resistance for backflow air is so small that it can be ignored.

<Face mode in comparative example>
Fig. 10 shows the airflow in blower 100 of the comparative example when the air conditioner is in face mode. As indicated by arrows F1 to F5 in Fig. 10, the airflow in blower 100 of the comparative example when the air conditioner is in face mode and blower 1 is operating is the same as that in blower 1 of the first embodiment. Therefore, in blower 100 of the comparative example, when the air conditioner is in face mode, the amount of backflow air is reduced, improving blowing efficiency and reducing noise.

<Foot mode or defroster mode in comparative example>
Next, FIG. 11 shows the airflow in the blower 100 of the comparative example when the air conditioner is in foot mode or defroster mode. When the fan 20 rotates, the main flow is drawn into the inter-blade flow passage 25 from the leading edge 26 of the fan 20 along the radially inner surface of the nozzle 60, as indicated by arrow F1 in FIG. 11 . As described above, when the air conditioner is in foot mode or defroster mode, the pressure loss in the flow passage downstream of the blower 100 is greater than in face mode. Therefore, as the rotation speed of the fan 20 increases, the difference in pressure between the air outlet 28 side of the fan 20 and the air inlet 2 side becomes greater than the pressure difference in face mode. As a result, when the wind speed and volume of air flowing back through the gap flow passage 84 increase, the backflow air flows over the end 61 of the nozzle 60 on the opposite side to the main plate and into the inside of the nozzle 60, as indicated by arrow F7 in FIG. 11 .

Here, as shown by arrows F8 to F13 in Figure 9, research by the inventors has revealed that the backflow air that crosses the end 61 of the nozzle 60 opposite the main plate and flows inside the nozzle 60 (hereinafter referred to as "backflow air crossing the nozzle 60") has a large circumferential wind speed distribution. That is, the multiple arrows F8 to F13 in Figure 9 indicate locations where the wind speed of the backflow air crossing the nozzle 60 is high. On the other hand, the wind speed of the backflow air crossing the nozzle 60 is low in the areas between the arrows F8 to F13 in Figure 9. As such, with the blower 100 of the comparative example, when the air conditioning system is in foot mode or defroster mode, the backflow air crossing the nozzle 60 may merge with the main flow while maintaining a large circumferential wind speed distribution and flow toward the leading edge 26 of the blade 22, potentially increasing noise.

<Operation and effect of the blower 1 according to the first embodiment>
In comparison with the blower 100 of the comparative example, the blower 1 of the first embodiment has the following advantages.
(1) The blower 1 of the first embodiment is equipped with flow path partition members 70 that are provided intermittently in the circumferential direction between the bell mouth 11 and the nozzle 60. These flow path partition members 70 divide the space between the nozzle 60 and the bell mouth 11 into a plurality of partition flow paths 73 through which air flows. By dividing the space between the nozzle 60 and the bell mouth 11 into a plurality of partition flow paths 73 using the flow path partition members 70, it is possible to increase the pressure loss of backflow air passing through the plurality of partition flow paths 73. Therefore, this blower 1 can reduce the wind speed and volume of backflow air and improve blowing efficiency.

Furthermore, as mentioned above, research by the inventors has revealed that backflow air that crosses the nozzle 60 has a large circumferential wind speed distribution, and that when this backflow air intersects with the main flow while maintaining its wind speed distribution and flows toward the leading edge 26 of the blade 22, noise increases. In contrast, the blower 1 of the first embodiment is able to reduce the circumferential wind speed distribution of the backflow air that crosses the nozzle 60 by using the flow path partition member 70 to increase the pressure loss of the backflow air passing through the partition flow path 73. Therefore, this blower 1 can reduce the noise generated when backflow air flows toward the leading edge 26 of the blade.

(2) In the first embodiment, the flow path partition members 70 are provided radially between the nozzle 60 and the bell mouth 11 so as to increase the pressure loss of air flowing through the plurality of partition flow paths 73 .
This illustrates a specific arrangement of the plurality of flow path partition members 70.

(3) In the first embodiment, the end 71 of the flow path partition member 70 on the side opposite to the main plate is located closer to the main plate 21 than the end 61 of the nozzle 60 on the side opposite to the main plate. In addition, the end 72 of the flow path partition member 70 on the side opposite to the main plate is located closer to the side opposite to the main plate than the end 62 of the nozzle 60 on the side opposite to the main plate 21.
With this, the flow path partition member 70 does not obstruct the main flow that passes from the flow path upstream of the nozzle 60 to the radially inner side of the nozzle 60 and is sucked into the fan 20 .

(4) In the first embodiment, the flow path partition members 70 are provided at uniform intervals in the circumferential direction between the bell mouth 11 and the nozzle 60 .
This makes it possible to reduce the wind speed and volume of the backflow air flowing through the partition flow passage 73 by uniformly increasing the pressure loss of the backflow air passing through the partition flow passage 73 in the circumferential direction, thereby reducing the wind speed distribution. Furthermore, even if the position of the circumferential wind speed distribution of the backflow air across the nozzle 60 changes due to the operating conditions of the blower 1, it is possible to reduce the wind speed distribution.

(5) In the first embodiment, the flow path partition member 70 is provided around the entire circumference between the bell mouth 11 and the nozzle 60 .
This increases the pressure loss of the backflow air passing through the partition flow path 73 over the entire circumference, thereby reducing the wind speed and volume of the backflow air flowing through the partition flow path 73, thereby making it possible to reduce the wind speed distribution. Furthermore, even if the position of the circumferential wind speed distribution of the backflow air across the nozzle 60 changes due to the operating conditions of the blower 1 or the like, it is possible to reduce the wind speed distribution.

(6) In the first embodiment, the fan 20 is a turbofan in which the blades 22 extend rearward in the direction of rotation from the leading edge 26 to the trailing edge 27. As a result, among centrifugal fans, a turbofan has the characteristic that the volume of backflow air tends to increase due to the large pressure difference between the air inlet 2 and the air outlet 28. Even a blower 1 equipped with a turbofan having such characteristics can achieve the effects of improving air blowing efficiency and reducing noise.

(7) In the first embodiment, the number of flow path partition members 70 is at least twice the number required to support the nozzles 60 .
According to this, by increasing the number of flow path partition members 70, the flow path cross-sectional area of each partition flow path 73 is reduced, and it is therefore possible to increase the pressure loss of the backflow air passing through the partition flow paths 73. Therefore, it is possible to reduce the air volume of the backflow air and reduce the circumferential wind speed distribution of the backflow air.

(Second to Fifth Embodiments)
The second to fifth embodiments are different from the first embodiment in the configuration of the flow path partition member 70, but are otherwise similar to the first embodiment, so only the parts that are different from the first embodiment will be described.

Second Embodiment
5 , in the second embodiment, the flow path partition member 70 provided between the bell mouth 11 and the nozzle 60 is configured in a mesh-like shape. The mesh of the mesh-like flow path forming member forms a plurality of partition flow paths 73. The mesh-like flow path partition member 70 is provided around the entire circumference between the bell mouth 11 and the nozzle 60 so as to increase the pressure loss of air passing through the plurality of partition flow paths 73.

The thickness of the mesh-like flow path forming member, the flow path cross-sectional area of the multiple partition flow paths 73, and the flow path length in the axial direction of the multiple partition flow paths 73 can be set as desired. Specifically, in Figure 5, the multiple partition flow paths 73 are shown to have a rectangular shape, but this is not limited to this, and the shape of the multiple partition flow paths 73 can be set as desired, for example, a circle, an ellipse, a polygon, or a combination thereof.

The mesh-like flow path partition member 70 provided in the blower 1 of the second embodiment described above also increases the pressure loss of the backflow air passing through the multiple partition flow paths 73, thereby reducing the wind speed and volume of the backflow air and making it possible to reduce the circumferential wind speed distribution of the backflow air across the nozzle 60. Therefore, the blower 1 of the second embodiment can also improve air blowing efficiency and reduce noise.

(Third embodiment)
As shown in FIG. 6 , in the third embodiment, the flow path partition members 70 are provided only within a predetermined angular range set at multiple locations in the circumferential direction between the bell mouth 11 and the nozzle 60. In FIG. 6 , the predetermined angular ranges in which the flow path partition members 70 are provided are indicated by arrows R1 to R3. In the third embodiment, three predetermined angular ranges are set. The predetermined angular ranges in which the flow path partition members 70 are provided are set at locations where the wind speed of backflow air crossing the nozzle 60 would be high if the flow path partition members 70 were not provided. These locations can be set through experiments, simulations, or the like. In this way, the blower 1 of the third embodiment has locations where the spacing between the multiple flow path partition members 70 is narrow and locations where the spacing between the multiple flow path partition members 70 is wide, so that the wind speed of backflow air crossing the nozzle 60 is uniform.

The blower 1 of the third embodiment described above can equalize the wind speed of the backflow air in the circumferential direction between the nozzle 60 and the bell mouth 11 by arranging the areas where the spacing between the multiple flow path partition members 70 is narrow in areas where the wind speed of the backflow air is high. This reduces the circumferential wind speed distribution of the backflow air across the nozzle 60, and reduces the wind speed and volume of the backflow air. Furthermore, the third embodiment can be configured so that no more flow path partition members 70 than necessary are provided.

(Fourth embodiment)
7 , in the fourth embodiment, the flow path partition members 70 are provided at uneven intervals in the circumferential direction between the bell mouth 11 and the nozzle 60. Note that uneven intervals in the circumferential direction mean that the intervals are uneven to the extent that they would be uneven if they were uniformly arranged in the circumferential direction, excluding manufacturing tolerances. For example, the intervals can be said to be uneven if the difference in cross-sectional area between the plurality of partition flow paths 73 formed by the plurality of flow path partition members 70 is greater than 5%.

The blower 1 of the fourth embodiment increases the pressure loss of the backflow air passing through the multiple partition flow paths 73, making it possible to equalize the wind speed of the backflow air. In other words, it is possible to reduce the circumferential wind speed distribution of the backflow air across the nozzle 60, thereby reducing the wind speed and volume of the backflow air.

Fifth Embodiment
The fifth embodiment is a modification of the third embodiment. As shown in FIG. 8 , in the fifth embodiment, the flow path partition members 70 are provided only in a predetermined angular range set at six locations in the circumferential direction between the bell mouth 11 and the nozzle 60. In FIG. 8 , the predetermined angular ranges in which the flow path partition members 70 are provided are indicated by arrows R1 to R6. The predetermined angular ranges in which the flow path partition members 70 are provided are set at locations where the wind speed of backflow air crossing the nozzle 60 would be high if the flow path partition members 70 were not provided. These locations can be set through experiments, simulations, or the like. In other words, the predetermined angular range in which the flow path partition members 70 are provided is not limited to the six locations shown in FIG. 8 , and can be set arbitrarily.

In this way, the blower 1 of the fifth embodiment also has areas where the spacing between the multiple flow path partition members 70 is narrow and areas where the spacing between the multiple flow path partition members 70 is wide, so that the wind speed of the backflow air across the nozzles 60 is uniform. The blower 1 of the fifth embodiment can also achieve the same effects as the third embodiment, etc.

Sixth Embodiment
The sixth embodiment will be described with reference to the drawings. The sixth embodiment is similar to the first embodiment except that the shroud tubular portion 32 is eliminated. Therefore, only the differences from the first embodiment will be described.

<Configuration of blower 1>
As shown in FIG. 12, the blower 1 of the sixth embodiment also includes a case 10, a fan 20, a drive unit 50, a nozzle 60, and a flow path partition member 70.
The fan 20 has a main plate 21, a plurality of blades 22, and a shroud 30. In the sixth embodiment, the shroud 30 has a shroud annular portion 31 connected to portions 23 of the plurality of blades 22 on the side opposite the main plate. However, in the sixth embodiment, the shroud 30 does not have a portion that extends cylindrically from a radially inner portion of the shroud annular portion 31 toward the side opposite the main plate (i.e., the shroud cylindrical portion 32 described in the first embodiment). The nozzle 60 is formed in a cylindrical shape and is provided from a region radially inner of the bell mouth 11 to a region radially inner of the case cylindrical portion 14. The other configurations of the blower 1 of the sixth embodiment are substantially the same as those described in the first embodiment.

As shown in Figures 12 and 13, multiple flow path partition members 70 are provided between the bell mouth 11 and the nozzle 60. The multiple flow path partition members 70 are provided intermittently in the circumferential direction between the bell mouth 11 and the nozzle 60, dividing the space between the nozzle 60 and the bell mouth 11 into multiple partition flow paths 73 through which air flows. The number, thickness, etc. of the multiple flow path partition members 70 are the same as those described in the first embodiment. That is, the number, thickness, etc. of the multiple flow path partition members 70 are set to increase the pressure loss of air passing through each partition flow path 73, reduce the axial and circumferential air flow in each partition flow path 73, and rectify the air flow in each partition flow path 73.

13 , in the sixth embodiment, a plurality of flow path partition members 70 are provided radially between the nozzle 60 and the bell mouth 11. The plurality of flow path partition members 70 are also provided around the entire circumference between the bell mouth 11 and the nozzle 60. The plurality of flow path partition members 70 are also provided at uniform intervals in the circumferential direction between the bell mouth 11 and the nozzle 60.
However, the number, shape, and arrangement of the flow path partition members 70 are not limited to those shown in FIG. 13, and the configurations described in the second to fifth embodiments can be applied.

<Operation of blower 1>
Next, the flow of air when the blower 1 of this embodiment is operated will be described with reference to FIGS. 14 and 15. FIG.

In the following description of the sixth embodiment, as shown in Figures 14 and 15, the space between the nozzle 60 and the bell mouth 11 on one side of the partition passage 73 in the axial direction is referred to as the first passage 81. Furthermore, the space between the nozzle 60 and the cylindrical case portion 14 on the other side of the partition passage 73 in the axial direction is referred to as the second passage 82. Furthermore, the space between the shroud 30 and the inner wall of the case 10 is referred to as the gap passage 84.

<Face Mode>
First, the air flow when the air conditioner is in face mode and the blower 1 is operating will be described with reference to Fig. 14. Generally, when the air conditioner is in face mode, the pressure loss in the flow path downstream of the blower 1 is smaller than in foot mode or defroster mode.

When the fan 20 rotates, air is drawn into the inter-blade flow passage 25 of the fan 20 from the radially inner region of the nozzle 60, as shown by arrow F1 in Figure 14. The air flow indicated by arrow F1 is called the main flow. Part of this main flow flows along the radially inner surface of the nozzle 60.

At the same time, as shown by arrows F2 and F3, air drawn into the fan 20 along the front wall 12 of the case 10 collides with the radially outer surface of the nozzle 60, flows along that surface through the first flow path 81, partition flow path 73, and second flow path 82, and is drawn into the inter-blade flow path 25 from the blade leading edge 26 side.

Furthermore, when the fan 20 rotates, the pressure at the air outlet 28 of the fan 20 becomes higher than the pressure on the suction port 2 side of the fan 20. Therefore, as shown by arrows F4 and F5, air flows in the gap passage 84, flowing backward from the air outlet 28 side to the suction port 2 side. Note that the air flowing backward through the gap passage 84 contains a velocity component in the rotation direction of the fan 20. The air flowing through the gap passage 84, shown by arrows F4 and F5, and the air flowing in from the first passage 81, shown by arrow F2, merge in the second passage 82, and are then sucked into the inter-blade passage 25 together with the main flow from the blade leading edge 26 side, as shown by arrow F3.

Here, the pressure of the air flowing along the radially outer surface of the nozzle 60 is higher than the pressure of the main air flowing into the fan 20 along the radially inner surface of the nozzle 60. Therefore, the pressure difference between the pressure in the first flow path 81, partition flow path 73, and second flow path 82 and the pressure on the air outlet 28 side of the fan 20 is reduced, and the amount of air flowing back through the gap flow path 84 from the air outlet 28 side of the fan 20 can be reduced.

In addition, when the air flowing through the first flow path 81 and the air flowing backward through the gap flow path 84 meet in the second flow path 82, the velocity component of the combined air in the rotational direction of the fan 20 becomes smaller. Therefore, the intersection angle between the air blown out from the second flow path 82 toward the blade leading edge 26 and the main flow becomes smaller, thereby reducing noise.

<Foot mode or defroster mode>
Next, the air flow when the air conditioner is in the foot mode or defroster mode and the blower 1 is operated will be described with reference to FIG.

As the fan 20 rotates, the main flow is drawn into the inter-blade passage 25 from the leading edge 26 of the fan 20 along the radially inner surface of the nozzle 60, as indicated by arrow F1 in FIG. 15 . Generally, when an air conditioning system is in foot mode or defroster mode, the pressure loss in the passage downstream of the blower 1 is greater than in face mode. Therefore, as the rotation speed of the fan 20 increases, the difference in pressure between the air outlet 28 and the air inlet 2 of the fan 20 becomes greater than the pressure difference in face mode. As a result, when the speed and volume of air flowing back through the gap passage 84 increase, the backflow air attempts to flow from the second passage 82 through the partition passage 73 and the first passage 81, straddling the end 61 of the nozzle 60 on the anti-main plate side, and into the inside of the nozzle 60, as indicated by dashed arrow F6 in FIG. 15 . In contrast, in the sixth embodiment, the space between the nozzle 60 and the bell mouth 11 is separated into multiple partitioned flow paths 73 by multiple flow path partition members 70, which increases the pressure loss of the backflow air passing through the partitioned flow paths 73 and reduces the wind speed and volume of the backflow air.

Furthermore, research by the inventors has revealed that the backflow air that attempts to flow inside the nozzle 60 across the end 61 on the side opposite the main plate has a large circumferential wind speed distribution. In contrast, in the first embodiment, the space between the nozzle 60 and the bellmouth 11 is partitioned into multiple partition flow paths 73 by multiple flow path partition members 70, which increases the pressure loss of the backflow air passing through these partition flow paths 73 and reduces the circumferential wind speed distribution of the backflow air.

Like the blower 1 described in the first embodiment and other embodiments, the blower 1 of the sixth embodiment described above is also capable of reducing the wind speed and volume of backflow air passing through the multiple partition flow paths 73 and reducing the circumferential wind speed distribution of backflow air across the nozzle 60. Therefore, the blower 1 of the sixth embodiment can also improve air blowing efficiency and reduce noise.

(Other embodiments)
(1) In each of the above embodiments, the blower 1 has been described as being used in a vehicle air conditioning system, but this is not limited thereto. The blower 1 can be used for various purposes, such as a ventilation system or an air blowing system.

(2) In the above embodiments, the fan 20 provided in the blower 1 is described as a turbofan, but this is not limited thereto. For example, it may be a centrifugal fan such as a sirocco fan or a radial fan.

(3) In the above embodiments, the nozzle 60 of the blower 1 has been described as having a blade shape whose diameter decreases from one side to the other in the axial direction and as being arranged to protrude beyond the front wall 12 of the case 10 on the side opposite the main board, but this is not limited to this. The nozzle 60 may, for example, be a simple cylindrical shape, and may not protrude beyond the front wall 12 of the case 10 on the side opposite the main board.

(4) In the above embodiments, the figures show examples of 14, 20, 21, and 24 flow path partition members 70, but this is not limitative and the number and shape of the flow path partition members 70 can be set as desired.

The present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate, except where such combinations are clearly impossible. It goes without saying that, in the above-described embodiments, the elements constituting the embodiments are not necessarily essential, except where expressly stated as essential or where they are clearly considered essential in principle. Furthermore, in the above-described embodiments, when the number, numerical value, amount, range, or other numerical value of the components of the embodiments is mentioned, it is not limited to that specific number, except where expressly stated as essential or where they are clearly limited to a specific number in principle. Furthermore, in the above-described embodiments, when the shape, positional relationship, etc. of the components, etc. are mentioned, they are not limited to that shape, positional relationship, etc., except where expressly stated as essential or where they are clearly limited to a specific shape, positional relationship, etc. in principle.

REFERENCE SIGNS LIST 1 blower 2 suction port 11 bell mouth 20 fan 21 main plate 22 blade 30 shroud 60 nozzle 70 flow path partition member 73 partition flow path

Claims (13)

In the blower,
A case (10) having a bell mouth (11) that forms an intake port (2) for drawing in air;
a fan (20) including a main plate (21) rotatably provided around a central axis (CL) inside the case, a plurality of blades (22) arranged around the central axis and connected to the main plate, and a shroud (30) connected to portions (23) of the plurality of blades on the opposite side to the main plate;
a cylindrical nozzle (60) provided in a radially inner region of the bell mouth;
and flow path partition members (70) that are provided intermittently in the circumferential direction between the nozzle and the bell mouth and that partition the space between the nozzle and the bell mouth into a plurality of partition flow paths (73) through which air flows,
The flow path partition members are configured to have an increased number and a greater thickness so that the pressure loss of air passing through the partition flow path increases compared to the number and thickness required to support the nozzles when viewed from the axial direction . The blower according to claim 1 , wherein the flow path partition members are provided radially between the nozzle and the bell mouth. A blower according to claim 1 or 2, wherein the flow path partition members are provided at uniform intervals in the circumferential direction between the nozzle and the bell mouth. In the blower,
A case (10) having a bell mouth (11) that forms an intake port (2) for drawing in air;
a fan (20) including a main plate (21) rotatably provided around a central axis (CL) inside the case, a plurality of blades (22) arranged around the central axis and connected to the main plate, and a shroud (30) connected to portions (23) of the plurality of blades on the opposite side to the main plate;
a cylindrical nozzle (60) provided in a radially inner region of the bell mouth;
and flow path partition members (70) that are provided intermittently in the circumferential direction between the nozzle and the bell mouth and that partition the space between the nozzle and the bell mouth into a plurality of partition flow paths (73) through which air flows,
The flow path partition member is provided in a net-like manner between the nozzle and the bell mouth so as to increase pressure loss of air flowing between the nozzle and the bell mouth. A blower according to any one of claims 1 to 4, wherein the flow path partition member is provided around the entire circumference between the nozzle and the bell mouth. an end (71) of the flow path partition member on the side opposite to the main plate is located closer to the main plate than an end (61) of the nozzle on the side opposite to the main plate,
6. The blower according to claim 1, wherein an end (72) of the flow path partition member on the side of the main board is located on the side opposite the main board from an end (62) of the nozzle on the side of the main board. In the blower,
A case (10) having a bell mouth (11) that forms an intake port (2) for drawing in air;
a fan (20) including a main plate (21) rotatably provided around a central axis (CL) inside the case, a plurality of blades (22) arranged around the central axis and connected to the main plate, and a shroud (30) connected to portions (23) of the plurality of blades on the opposite side to the main plate;
a cylindrical nozzle (60) provided in a radially inner region of the bell mouth;
a plurality of flow path partition members (70) provided between the nozzle and the bell mouth and partitioning the space between the nozzle and the bell mouth into a plurality of partition flow paths (73) through which air flows;
a blower having a plurality of flow path partition members at locations where the spacing between them is narrow and a plurality of the flow path partition members at locations where the spacing between them is wide, so that the wind speed of air flowing back through the space formed between the nozzle and the bell mouth from the air outlet side of the fan through the plurality of partition flow paths to the air inlet side inside the nozzle is made uniform. The blower of claim 7, wherein the plurality of flow path partition members are provided only within a predetermined angular range set at multiple locations in the circumferential direction between the nozzle and the bell mouth. A blower as described in claim 7, wherein the multiple flow path partition members are arranged at uneven intervals in the circumferential direction between the nozzle and the bell mouth. A blower according to any one of claims 1 to 9, wherein the fan is a turbofan in which the blades extend rearward in the direction of rotation from the leading edge to the trailing edge. 8. The blower according to claim 4 , wherein the number of the flow path partition members is at least twice the number required to support the nozzles. A blower as described in any one of claims 1 to 11, wherein the shroud has a shroud annular portion (31) connected to the portions (23) of the blades on the side opposite the main board, and does not have a portion of the shroud annular portion that extends cylindrically from the radially inner portion toward the side opposite the main board. A blower as described in any one of claims 1 to 11, wherein the shroud has a shroud annular portion (31) connected to the portions (23) of the blades on the side opposite the main board, and a shroud cylindrical portion (32) extending cylindrically from the radially inner portion of the shroud annular portion toward the side opposite the main board.