WO2024224478A1 - 送風機 - Google Patents

送風機 Download PDF

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Publication number
WO2024224478A1
WO2024224478A1 PCT/JP2023/016275 JP2023016275W WO2024224478A1 WO 2024224478 A1 WO2024224478 A1 WO 2024224478A1 JP 2023016275 W JP2023016275 W JP 2023016275W WO 2024224478 A1 WO2024224478 A1 WO 2024224478A1
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WO
WIPO (PCT)
Prior art keywords
point
air guide
blower
blade
wall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2023/016275
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English (en)
French (fr)
Japanese (ja)
Inventor
直彦 本間
誠 谷島
智哉 福井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP2023579718A priority Critical patent/JP7487854B1/ja
Priority to PCT/JP2023/016275 priority patent/WO2024224478A1/ja
Publication of WO2024224478A1 publication Critical patent/WO2024224478A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/38—Blades
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/52—Casings; Connections of working fluid for axial pumps
    • F04D29/54—Fluid-guiding means, e.g. diffusers

Definitions

  • This disclosure relates to a blower equipped with a bellmouth.
  • a blower is disclosed that is provided with a casing that has a cylindrical air guide section that covers the outer periphery of the impeller and an annular bell mouth that guides air into the air guide section (for example, Patent Document 1).
  • blower Also known is a type of blower called a semi-open type, in which part of the blade, or wing, protrudes beyond the surface that includes the most upstream point of the bellmouth.
  • This disclosure has been made to solve the problems described above, and aims to provide a semi-open type blower equipped with a casing having an air guide section and a bell mouth, which narrows the tip clearance and suppresses noise.
  • the blower according to the present disclosure comprises a boss that is driven to rotate around a rotating shaft by a motor, blades that are arranged radially from the boss and generate airflow by rotation, an air guide section arranged to cover the outer peripheral end of the blade, a downstream end that is arranged between the upstream side of the airflow of the air guide section and the blade, and an upstream end that is arranged to cover the upstream side of the air guide section, and a bellmouth having a portion of the blade arranged upstream of the upstream end of the bellmouth, and the air guide section is characterized in that the inner wall facing the blade has a protrusion that protrudes in the direction towards the blade, downstream of the airflow from the downstream end of the bellmouth.
  • the blower disclosed herein can reduce tip clearance and reduce noise.
  • FIG. 1 is a perspective view of a blower according to a first embodiment of the present disclosure.
  • 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • FIG. 1 is a schematic diagram illustrating a radial cross section of a blower according to a first embodiment of the present disclosure.
  • 1 is a graph showing a relationship between an air volume Q and a noise level SPL in a blower according to a first embodiment of the present disclosure.
  • FIG. 11 is a schematic diagram illustrating a radial cross section of a blower according to a second embodiment of the present disclosure.
  • FIG. 13 is a schematic diagram illustrating a radial cross section of a blower according to a third embodiment of the present disclosure.
  • FIG. 11 is a schematic diagram illustrating a radial cross section of a blower according to a fourth embodiment of the present disclosure.
  • FIG. 13 is a schematic diagram showing a radial cross section of a blower according to a fifth embodiment of the present disclosure.
  • FIG. 1 is a perspective view of the blower 101 according to the first embodiment.
  • the blower 101 includes an impeller 1 and a casing 2 that surrounds the impeller 1.
  • the blower 101 also includes a motor (not shown).
  • the blower 101 is, for example, an axial flow blower.
  • the blower 101 shown in FIG. 1 is equipped with a propeller fan as an impeller 1.
  • the blower 101 may also be a cross-flow blower.
  • Impeller 1 draws in airflow from the top of impeller 1 downward in the axial direction of rotating shaft RS (in the direction of arrow F) in the drawing, and expels the airflow to the bottom of impeller 1 downward in the axial direction of rotating shaft RS (in the direction of arrow F).
  • the side where the airflow is drawn in is the upstream side
  • the side where the airflow is expelled is the downstream side.
  • the upper side of the paper in Figure 1 is the upstream side
  • the lower side of the paper is the downstream side.
  • the upstream side and downstream side are not necessarily based on impeller 1, but rather define the upstream side and downstream side for each configuration when the airflow is used as the reference for each configuration.
  • the impeller 1 includes a boss 3 and a plurality of blades 4 provided on the outer periphery of the boss 3.
  • a motor (not shown) is connected to the boss 3 and is provided inside or downstream of the boss 3.
  • the boss 3 is driven to rotate about the rotation axis RS by the driving force of the motor.
  • the impeller 1 is driven to rotate about the rotation axis RS by the driving force of the motor. In FIG. 1, for example, the impeller rotates in the counterclockwise direction R when viewed from the top of the drawing.
  • the boss 3 is, for example, cylindrical. Note that the boss 3 is not limited to being cylindrical, and may be, for example, a truncated cone shape or another shape.
  • the blades 4 are arranged radially outward from the boss 3 on the outer periphery of the boss 3.
  • the blades 4 generate airflow when they rotate.
  • the blower 101 shown in FIG. 1 has three blades 4. Note that the number of blades 4 is not limited to three, and may be, for example, four or more.
  • Each of the blades 4 has a predetermined three-dimensional shape.
  • the blades 4 are formed as forward-swept blades with a blade leading edge 5 that faces forward in the direction of rotation (the direction of the arrow R) and extends forward.
  • the blades 4 also have a blade trailing edge 6 that is located rearward of the blade leading edge 5 in the direction of rotation of the impeller 1 (the direction of the arrow R) and downstream of the blade leading edge 5.
  • the blades 4 also have an outer peripheral edge 7 between the blade leading edge 5 and the blade trailing edge 6.
  • the casing 2 is arranged to cover the outer peripheral end 7 of the impeller 1.
  • Figure 2 is a schematic diagram showing a radial cross section of blower 101 according to embodiment 1. Specifically, Figure 2 is a cross section of blower 101 including rotation axis RS, rotated and projected onto a plane parallel to rotation axis RS.
  • the blade 4 has an outer peripheral end 7.
  • the outer peripheral portion 25 is the area through which the outer peripheral end 7 of the blade 4 passes when a cross section including the rotation axis RS is rotated and projected onto a plane parallel to the rotation axis RS.
  • the outer peripheral portion 25 includes, for example, a straight line shape. Therefore, the outer peripheral end 7 of the blade 4 is positioned so that it overlaps with the outer peripheral portion 25 upon rotation.
  • the area shown between the boss 3 and the casing 2 is the area through which the blade 4 passes when rotated, projected onto a plane including the rotation axis RS.
  • the casing 2 includes an air guide section 8 that covers the outer circumferential ends 7 of the blades 4, a bell mouth 9 that guides airflow inside the air guide section 8, and a flange section 10 that is continuous with the bell mouth 9.
  • the air guide section 8 is arranged to cover the outer peripheral end 7 of the blade 4.
  • the air guide section 8 includes an inner wall 11 facing the blade 4 and an outer wall 26 opposite the inner wall 11.
  • the inner wall 11 of the air guide section 8 has, for example, a shape that is axially symmetrical with respect to the rotation axis RS.
  • the impeller 1 is disposed inside the air guide section 8, i.e., on the rotation axis RS side of the air guide section 8. It is desirable that the shape of the inner wall 11 of the air guide section 8 is axially symmetrical with respect to the rotation axis RS, but it may be non-axially symmetrical depending on the combination of the inner wall 11 and the three-dimensional shape of the impeller 1.
  • the air guide section 8 includes an intake end 12 located on the upstream side and an exhaust end 13 located on the downstream side. The airflow flows from the intake end 12 to the exhaust end 13 of the air guide section 8.
  • the bellmouth 9 is formed continuously with the flange portion 10.
  • the bellmouth 9 has a cylindrical shape whose inner diameter changes in the axial direction of the rotation shaft RS.
  • the bellmouth 9 is provided so as to cover the upstream side of the air guide section 8.
  • the bellmouth 9 is provided so as to cover the suction side end 12 of the air guide section 8.
  • the bellmouth 9 is provided away from the suction side end 12 located upstream of the air guide section 8.
  • the bellmouth 9 includes a downstream end 14 and an upstream end 15.
  • the downstream end 14 is located at the most downstream position of the bellmouth 9 and is provided between the blades 4 of the impeller 1 and the upstream side of the air guide section 8.
  • the upstream end 15 is located at the most upstream position of the bellmouth 9 and is provided so as to cover the upstream side of the air guide section 8.
  • the bellmouth 9 is positioned near the suction side end 12 of the air guide section 8 so as to overlap partially with the air guide section 8 in the axial direction of the rotation axis RS.
  • the bell mouth 9 has an inner peripheral surface 16 on the inside, i.e., on the side facing the impeller 1.
  • the bell mouth 9 also has an outer peripheral surface 17 on the outside, i.e., on the side opposite the impeller 1.
  • the bellmouth 9 forms a first ventilation passage 18 on the inside.
  • the bellmouth 9 also forms a second ventilation passage 19 on the outside.
  • the second ventilation passage 19 is formed between the outer peripheral surface 17 of the bellmouth 9 and the inner wall 11 of the air guide section 8.
  • the first ventilation passage 18 includes a third ventilation passage 20.
  • the third ventilation passage 20 is an air passage formed between the bellmouth 9 and the blade 4 and between the air guide section 8 and the blade 4.
  • the inner circumferential surface 16 and the outer circumferential surface 17 of the bellmouth 9 are formed, for example, in a curved shape that is convex in the direction toward the blade 4.
  • the inner circumferential surface 16 and the outer circumferential surface 17 of the bellmouth 9 are formed, for example, in an arc shape. Note that the inner circumferential surface 16 and the outer circumferential surface 17 of the bellmouth 9 may be partially curved, or may be formed by combining straight lines.
  • the flange portion 10 is provided continuous with the upstream end portion 15 of the bell mouth 9.
  • the flange portion 10 is provided so as to cover the upstream side of the air guide portion 8.
  • the blade 4 is provided at a position facing the casing 2, and is provided upstream of the upstream end 15 of the bellmouth 9, a portion of which is included in the casing 2.
  • the blade 4 in the positional relationship between the blade 4 and the bellmouth 9 in the direction of the rotation axis RS, the blade 4 is provided so that a portion of the blade 4 includes the upstream end 15 of the bellmouth 9 and protrudes upstream from a plane perpendicular to the rotation axis RS.
  • impellers 1 in which some of the blades 4 are located upstream of the casing 2 are often used in air conditioner outdoor units and ventilation fans, and are sometimes called half-ducted or semi-open types.
  • FIG. 3 is a schematic diagram showing a radial cross section of blower 101 according to embodiment 1. Specifically, FIG. 3 is a cross section obtained by rotating and projecting a cross section of blower 101 including rotation axis RS onto a plane parallel to rotation axis RS. The flow of air in blower 101 according to embodiment 1 will be described using FIG. 3.
  • the blower 101 takes in air from the upstream side of the blower 101, i.e., the upper side of the paper in FIG. 3, into the first ventilation passage 18.
  • the air taken in the first ventilation passage 18 passes between the blades 4 attached to the impeller 1 arranged in the first ventilation passage 18, and between the casing 2 and the blades 4 in the direction of arrow F, and is discharged downstream, i.e., the lower side of the paper in FIG. 3.
  • the rotational motion of the blades creates a leakage flow from the downstream side of the blade to the upstream side.
  • a tip clearance which is the gap between the blade 4 and the air guide section 8, as in the blower 101 of this embodiment, a backflow 21 from the downstream side to the upstream side occurs at the outer circumferential end 7 of the blade 4, as shown in Figure 3.
  • the backflow 21 creates turbulence in the airflow and causes noise.
  • the F1 shown in FIG. 3 is a portion of the airflow passing through the first ventilation passage 18.
  • the airflow F1 is taken into the first ventilation passage 18 from the upstream side of the blower 101, i.e., the upstream side of the flange portion 10 and the upstream side of the bellmouth 9.
  • the airflow F1 passes between the bellmouth 9 and the blade 4 and between the air guide portion 8 and the blade 4, and is discharged from the discharge end portion 13 of the air guide portion 8 in the downstream direction of the blower 101.
  • the airflow F1 is an airflow that passes through the first ventilation passage 18, particularly the third ventilation passage 20.
  • the flange portion 10 and the bell mouth 9 are arranged to cover the suction side end portion 12 located upstream of the air guide portion 8, so that the suction side end portion 12 of the air guide portion 8 does not come into contact with the airflow F1.
  • FIG. 3 is an airflow passing through the second ventilation passage 19.
  • the airflow F2 is drawn into the second ventilation passage 19 from the inlet of the second ventilation passage 19.
  • the airflow F2 passes between the bell mouth 9 and the air guide section 8, and is discharged from the outlet of the second ventilation passage 19 to the third ventilation passage 20.
  • the inlet of the second ventilation passage 19 is formed between the suction side end 12 of the air guide section 8 and the bell mouth 9.
  • the outlet of the second ventilation passage 19 is formed between the air guide section 8 and the downstream end 14 of the bell mouth 9.
  • Airflow F2 is drawn into the second ventilation passage 19, for example, from the rear surface 24 of the flange portion 10 or near the downstream discharge end 13. Because the pressure near the suction end 12 of the air guide portion 8 is lower than the pressure near the discharge end 13 of the air guide portion 8, the airflow is taken into the second ventilation passage 19 due to the pressure difference, and the airflow F2 passes through the second ventilation passage 19 due to the pressure difference.
  • the airflow F2 that passes through the second ventilation passage 19 is supplied to the third ventilation passage 20 as a jet 22.
  • the jet 22 suppresses the backflow 21 that occurs at the outer circumferential end 7 of the blade 4, thereby reducing noise.
  • Figure 4 is a schematic diagram showing a radial cross section of the blower 101 according to the first embodiment. Specifically, Figure 4 is a cross section obtained by rotating and projecting a cross section of the blower 101 including the rotation axis RS onto a plane parallel to the rotation axis RS. The shape of the inner wall 11 of the air guide section 8 according to the first embodiment will be described using Figure 4.
  • the air guide section 8 has a protruding portion 23 that protrudes toward the blade 4 on the inner wall 11 facing the blade 4, downstream of the downstream end 14 of the bellmouth 9 in the airflow.
  • the outer wall 26 of the air guide section 8 has a shape that follows the protruding portion 23 of the inner wall 11, for example.
  • the outer peripheral portion 25 through which the outer peripheral end 7 of the blade 4 passes includes, for example, a straight line shape.
  • a straight line including the outer peripheral end 7 of the blade 4 is defined as a straight line L.
  • the outer circumferential portion 25 overlaps with the outer circumferential end 7. That is, in a cross-sectional view obtained by rotating and projecting the cross section of the blower 101 including the rotation axis RS onto a plane parallel to the rotation axis RS, the straight line including the outer circumferential portion 25 is also the straight line L.
  • an arbitrary point included in the inner wall 11 of the air guide section 8 is defined as point A.
  • a perpendicular line drawn from point A to a line L through an arbitrary point included in the inner wall 11 of the air guide section 8 intersects with line L and defines point A'.
  • the length of the line segment connecting point A and point A' is defined as ⁇ A.
  • the point that is the shortest distance from the outer peripheral end 7, i.e., the point with the smallest distance ⁇ A, is defined as point Amin.
  • the point where the perpendicular line drawn from point Amin to line L intersects with line L is defined as point Amin'.
  • the length of the line segment connecting points Amin and Amin' is defined as ⁇ Amin.
  • Point Amin' is a point on line L at which the distance between line L including outer periphery 25 and protrusion 23 of inner wall 11 in the area in which blade 4 rotates is the smallest in a cross section including rotation axis RS of blade 4, and is the first point.
  • Point Amin is a point on inner wall 11 at which the distance between protrusion 23 of inner wall 11 and line L is the smallest, and is the second point.
  • the air guide section 8 has a point Amin where ⁇ A is minimum downstream of the downstream end 14 of the bellmouth 9. That is, the inner wall 11 of the air guide section 8 has a protrusion 23 that protrudes in the direction toward the blade 4 downstream of the downstream end 14 of the bellmouth 9.
  • the tip clearance which is the distance between the blade 4 and the air guide section 8 becomes wider.
  • the effect of the jet 22 in suppressing the backflow 21 at the outer circumferential end 7 of the blade 4 becomes smaller.
  • the inner wall 11 of the air guide section 8 is formed so that the distance ⁇ A is smaller on the downstream side than on the upstream side, which generates a negative pressure gradient and accelerates the jet 22 supplied to the third ventilation passage 20. Accelerating the jet 22 increases the momentum of the jet 22. Increasing the momentum of the jet 22 makes it possible to further suppress the backflow 21 at the outer circumferential end 7 of the blade 4. Suppressing the backflow 21 makes it possible to reduce noise.
  • the inner wall 11 of the air guide section 8 has a protrusion 23 that protrudes toward the blade 4 downstream of the downstream end 14 of the bellmouth 9, thereby narrowing the tip clearance and suppressing noise.
  • the first point is preferably included in the outer periphery 25 of the area in which the blades 4 rotate.
  • the point Amin' is preferably located on the outer periphery 7.
  • the inner wall 11 of the air guide section 8 is preferably shaped so as to be parallel to the line L or to be shaped in a direction away from the line L downstream of the point Amin.
  • the flow velocity of the jet 22 flowing through the third ventilation passage 20 is greatest at the point where the distance between the inner wall 11 of the air guide section 8 and the outer peripheral end 7 of the blade 4 is the smallest, i.e., at point Amin where the distance ⁇ A becomes the distance ⁇ Amin. Therefore, when point Amin' is located on the outer peripheral end 7, the occurrence of backflow 21 can be most effectively suppressed. By effectively suppressing backflow 21, noise can be reduced.
  • Figure 5 is a schematic diagram showing a radial cross section of the blower 101 according to the first embodiment. Specifically, Figure 5 is a cross section obtained by rotating and projecting a cross section of the blower 101 including the rotation axis RS onto a plane parallel to the rotation axis RS. The positional relationship between the inner wall 11 and the bell mouth of the air guide section 8 according to the first embodiment and the blades 4 will be described using Figure 5.
  • the downstream end 14 of the bellmouth 9 is the point located furthest downstream of the bellmouth 9.
  • the point where a perpendicular line drawn from point B to line L intersects with line L is called point B'.
  • the length of the line segment connecting points B and B' is called ⁇ B.
  • any point included in the inner wall 11 of the air guide section 8, downstream of point B and upstream of point Amin, is defined as point C.
  • the point where a perpendicular line drawn from point C to line L intersects with line L is defined as point C'.
  • the length of the line segment connecting points C and C' is defined as ⁇ C.
  • Point C which satisfies ⁇ C> ⁇ B and ⁇ C> ⁇ Amin, exists on the inner wall 11 of the air guide section 8.
  • the curve of the third ventilation passage 20 connecting points B, C, and Amin has a shape that is convex toward the air guide section 8.
  • Airflow F2 in the second ventilation passage 19 is slower than airflow F2 passing through the third ventilation passage 20. That is, there is a speed difference between airflow F2 and airflow F1.
  • point C which satisfies ⁇ C> ⁇ B, downstream of point B and upstream of point Amin
  • the speed of airflow F1 can be slowed down at the outlet of the second ventilation passage 19, i.e., where the jet 22 supplied from the second ventilation passage 19 joins the airflow F1.
  • the difference in speed between the jet 22 and the airflow F1 can be reduced, and the loss when the jet 22 and the airflow F1 join can be reduced.
  • Figure 6 is a schematic diagram showing a radial cross section of a blower 101 according to embodiment 1. Specifically, Figure 6 is a cross section obtained by rotating and projecting a cross section of the blower 101 including the rotation axis RS onto a plane parallel to the rotation axis RS. The positional relationship between the inner wall 11 and bell mouth 9 of the air guide section 8 according to embodiment 1 and the blades 4 will be described using Figure 6.
  • the bellmouth 9 has, for example, a circular arc shape with a single curvature from the upstream end 15 to the downstream end 14.
  • the point closest to the rotation axis RS i.e., the point that is the shortest distance from the rotation axis RS, is defined as the minimum radius point B1 of the bellmouth 9.
  • the minimum radius point B1 is preferably located at the upstream end 15 of the bellmouth 9 downstream of point B2, which is the most upstream point of the bellmouth 9, and upstream of point B.
  • the bellmouth 9 has a convex shape toward the blade 4 between the upstream end 15 and the downstream end 14.
  • Figure 6 shows the case where the apex of the convex shape on the blade 4 side is the minimum radius point B1.
  • B1' be the point where the perpendicular line drawn from the minimum radius point B1 to the line L intersects with the line L.
  • ⁇ B1 be the length of the line segment connecting points B1 and B1'.
  • the distance between the minimum radius point B1 and the straight line L is smaller than the distance between the second point ⁇ Amin and the straight line L. In other words, ⁇ B1 ⁇ Amin. Also, the distance between the minimum radius point B1 and the straight line L is smaller than the distance between the downstream end 14 and the straight line L. In other words, ⁇ B1 ⁇ B.
  • FIG. 7 is a schematic diagram showing a radial cross section of blower 101 according to embodiment 1. Specifically, FIG. 7 is a cross section obtained by rotating and projecting a cross section of blower 101 including rotation axis RS onto a plane parallel to rotation axis RS. The casing 2 will be described with reference to FIG. 7.
  • the flange portion 10 and the air guide portion 8, which are provided continuously with the bellmouth 9, may be provided partially continuous.
  • a cross section including the rotation axis RS there may be a cross section in which the flange portion 10 and the air guide portion 8 are connected and a cross section in which the flange portion 10 and the air guide portion 8 are not connected.
  • the outer peripheral end 7 of the blade 4 is straight, but the outer peripheral end 7 may also be curved. If the outer peripheral end 7 is curved in the cross-sectional view rotated and projected onto a plane parallel to the rotation axis RS, the straight line L is, for example, a straight line that is parallel to the straight line obtained by approximating the curved outer peripheral end 7 in the cross-sectional view rotated and projected onto a plane parallel to the rotation axis RS with a linear function and is tangent to the outer peripheral end 7.
  • FIG. 8 is a graph showing the relationship between the air volume Q and the noise level SPL (unit: dBA) in the blower 101 according to the first embodiment.
  • the horizontal axis is the air volume Q [m3/min]
  • the vertical axis is the SPL [dBA].
  • the solid line g1 is the result obtained in an experiment using the blower 101.
  • the dashed line g2 is the result obtained in an experiment using a typical semi-open type blower provided with a casing having an air guide section and a bell mouth.
  • the shape of the impeller used in the typical semi-open type blower is the same as the shape of the impeller 1 of the blower 101.
  • the noise level obtained with the blower 101 according to the first embodiment has a noise reduction effect of up to about 2 dB over a wide range of air volumes Q, compared to a typical semi-open type blower.
  • Embodiment 2 A blower 102 in the second embodiment will be described with reference to Fig. 9. Descriptions of the same configuration as in the first embodiment will be omitted.
  • Fig. 9 the same reference numerals as in Figs. 1 to 8 denote the same or corresponding parts.
  • Figure 9 is a schematic diagram showing a radial cross section of the blower 102 according to the second embodiment. Specifically, Figure 9 is a cross section obtained by rotating and projecting the cross section of the blower 102 including the rotation axis RS onto a plane parallel to the rotation axis RS. The air guide section 31 will be described using Figure 9.
  • the inner wall 11 of the air guide section 31 has a protruding portion 23.
  • the outer wall 26 on the side of the air guide section 31 opposite the blade 4 does not have a shape that conforms to the protruding portion 23 of the inner wall 11, as shown in FIG. 9, and may have a flat shape.
  • the outer wall 26 may also have a shape that protrudes radially outward, or may have a curved shape.
  • Embodiment 3 A blower 103 according to the third embodiment will be described with reference to Fig. 10. Descriptions of configurations similar to those of the first embodiment will be omitted.
  • Fig. 10 the same reference numerals as those in Figs. 1 to 9 denote the same or corresponding parts.
  • Figure 10 is a schematic diagram showing a radial cross section of a blower 103 according to embodiment 3. Specifically, Figure 10 is a cross section obtained by rotating and projecting a cross section of the blower 103 including the rotation axis RS onto a plane parallel to the rotation axis RS.
  • the impeller 32 of the blower 103 in this embodiment is an axial fan.
  • the blower 103 is an axial blower.
  • the air guide section 33 be provided approximately parallel to the outer circumferential end 7 of the blades 34 of the impeller 32.
  • Embodiment 4 A blower 104 according to the fourth embodiment will be described with reference to Fig. 11. Descriptions of configurations similar to those of the first embodiment will be omitted.
  • Fig. 11 the same reference numerals as those in Figs. 1 to 10 denote the same or corresponding parts.
  • Figure 11 is a schematic diagram showing a radial cross section of a blower 104 according to embodiment 4. Specifically, Figure 11 is a cross section obtained by rotating and projecting a cross section of the blower 104 including the rotation axis RS onto a plane parallel to the rotation axis RS.
  • the inner wall 36 of the air guide section 35 has a streamlined shape.
  • point Amax the point that is downstream of the downstream end 14 of the bellmouth 9 and has the greatest distance from the outer circumferential end 7, i.e., the point with the greatest distance ⁇ A
  • point Amax' the point where a perpendicular line drawn from point Amax to line L intersects with line L.
  • the length of the line segment connecting point Amax and point Amax' is defined as ⁇ Amax.
  • the inner wall 36 of the air guide section 35 has a generally streamlined shape with a curvature at least from point Amax to point Amin.
  • the airflow that flows into the second ventilation passage 19 from the inlet of the second ventilation passage 19 passes through point Amax on the inner wall 36 of the air guide section 35, and then experiences a negative pressure gradient in the flow direction.
  • the inner wall 36 of the air guide section 35 is approximately streamlined from point Amax to point Amin, the airflow can flow with reduced fluid resistance.
  • the jet 22 supplied from the second ventilation passage 19 and flowing toward the discharge end 13 of the air guide section 35 can flow while suppressing the energy consumption of the flow. Because the jet 22 can flow while suppressing the energy consumption of the flow, the backflow 21 can be further suppressed and the noise can be further reduced.
  • Embodiment 5 A blower 105 in the fifth embodiment will be described with reference to Fig. 12. Descriptions of the same configurations as those in the first and fourth embodiments will be omitted. In Fig. 12, the same reference numerals as those in Figs. 1 to 11 denote the same or corresponding parts.
  • Figure 12 is a schematic diagram showing a radial cross section of a blower 105 according to embodiment 5. Specifically, Figure 12 is a cross section of the blower 105 including the rotation axis RS, rotated and projected onto a plane parallel to the rotation axis RS.
  • the inner wall 36 of the air guide section 35 is formed so as to be away from the rotation axis RS at least downstream of point Amin.
  • the inner wall 36 may be smoothly connected to point Amin downstream of point Amin and have a sector shape with a central angle of 90 degrees and a radius equal to the radius of the arc shape of the bellmouth 9. It is desirable that the inner wall 36 be a curved surface having an approximately streamlined shape from point Amax to point Amin.
  • the airflow that flows into the second ventilation passage 19 from its inlet flows into the third ventilation passage 20, and is accelerated by the negative pressure gradient before reaching point Amin on the inner wall 36 of the air guide section 35, suppressing the backflow 21 that occurs at the outer circumferential end 7 of the blade 4.
  • the inner wall 36 is formed so as to move away from the rotation axis RS downstream of point Amin, so that after the airflow flowing through the third ventilation passage 20 passes near point Amin, the airflow gradually decelerates while the static pressure is restored.
  • the airflow passing downstream of point Amin on the inner wall 36 decelerates while the static pressure is restored, which prevents turbulence of the airflow, reduces noise, and improves ventilation performance.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
PCT/JP2023/016275 2023-04-25 2023-04-25 送風機 Ceased WO2024224478A1 (ja)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58168795U (ja) * 1982-05-07 1983-11-10 株式会社三協精機製作所 オルゴ−ルの調速機構
JP2002195199A (ja) * 2000-12-27 2002-07-10 Mitsubishi Electric Corp 送風装置及びそれを用いた空気調和機

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Publication number Priority date Publication date Assignee Title
JPS6145353Y2 (https=) * 1981-04-20 1986-12-19

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58168795U (ja) * 1982-05-07 1983-11-10 株式会社三協精機製作所 オルゴ−ルの調速機構
JP2002195199A (ja) * 2000-12-27 2002-07-10 Mitsubishi Electric Corp 送風装置及びそれを用いた空気調和機

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