JP2005201095A - Centrifugal blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal blower which improves blowing efficiency and can reduce power consumption. <P>SOLUTION: The centrifugal blower 1 is constituted so that the periphery of a Sirocco fan 2 is covered with a casing 3. The casing 3 is provided with an air intake port 3a disposed on the shaft of the Sirocco fan 2 and a blow off section 3c extending from the periphery, and an air flow passage 3h of Archimedes spiral shape is formed on the periphery of the Sirocco fan 2. The air taken from the air intake port 3a into the casing 3 flows through the air flow passage 3h from the low pressure side 6a to the high pressure side 6b and is fed out of the blow off section 3c. Widening sections 3a and 3j for widening the air flow passage 3h are disposed in the axial direction of the periphery of the Sirocco fan 3. On the boundary between the high pressure side 6b and the low pressure side 6a, rib-like blocking sections 7a and 7b are disposed on the inner surface side of the widening sections 3a and 3j, and the air on the high pressure side is blocked by the blocking sections 7a and 7b to prevent inflow to the low pressure side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a centrifugal blower that has a sirocco fan and blows air.

  A conventional centrifugal blower is disclosed in Patent Document 1. 8 and 9 are a side sectional view and a plan view showing the centrifugal blower. The centrifugal blower 1 has a sirocco fan 2 in which a plurality of blades 2a are provided radially. Both ends of each blade 2a in the axial direction are connected by a ring 2b and a back plate 2c, respectively. A boss 2d is formed at the center of the back plate 2c. A motor shaft 4a of the motor 4 is connected to the boss 2d. The motor 4 is fixed to the casing 3 by a fixing member 5. Thereby, the sirocco fan 2 is rotated by driving the motor 4.

  The sirocco fan 2 is covered with a casing 3, and an annular air flow path 3h is formed around it. The casing 3 is provided with an intake port 3a that is open in one axial direction. A bell mouth 3b whose diameter increases toward the outside is provided at the periphery of the air inlet 3a. A large amount of air can be smoothly sucked by the bell mouth 3b.

  A step portion 3 j is formed in the vicinity of the peripheral portion of the sirocco fan 2 on the back surface of the casing 3. The end of the bell mouth 3b and the surface of the step 3j facing the sirocco fan 2 are close to the sirocco fan 2. Further, the casing 3 is widened in the axial direction with respect to the sirocco fan 2 portion by the bell mouth 3b and the step portion 3j.

  The peripheral wall of the casing 3 is formed in an Archimedean spiral, and the side with the smaller diameter is close to the blade 2a. A duct-shaped blowing portion 3c is provided to protrude on the side of the casing 3 having a large diameter. One side wall 3f of the blowout portion 3c is formed to extend from the peripheral wall of the casing 3 in the tangential direction. The other side wall 3g of the blowing portion 3c is formed by bending from the side of the peripheral wall of the casing 3 having a small diameter. As a result, a tongue portion 3e having a tongue shape in plan view is formed, and the inside of the casing 3 is separated into a low pressure side 6a and a high pressure side 6b by the tongue portion 3e.

  In the centrifugal blower 1 having the above configuration, when the motor 4 is driven, air flows into the casing 6 from the air inlet 2a by the rotation of the sirocco fan 2. The air that has flowed into the casing 6 is pushed out in the outer peripheral direction of the casing 3 by the centrifugal force of the sirocco fan 2, and is circulated as shown by an arrow A1 to flow through the air flow path 3h from the low pressure side 6a to the high pressure side 6b. At this time, the air reaching the high-pressure side 6a is restricted from entering the low-pressure side 6a by the tongue 3e adjacent to the blade 25, so that the blowing efficiency is improved.

And it is exhausted from the exhaust port 3d through the blowing part 3c as shown by arrow A2. As a result, the centrifugal blower 1 is mounted on an air conditioner or the like, so that the airflow direction can be varied and the air can be blown.
JP-A-64-41700 (pages 1 to 3 and FIG. 6)

  However, according to the conventional centrifugal blower 1, the space 9 is formed on the inner surface side of the bell mouth 3 b and the step portion 3 j that overlap the peripheral portion of the sirocco fan 2. For this reason, a part of the air that has reached the high-pressure side 6b wraps around the low-pressure side 6a through the space 9, and the blowing efficiency is reduced. As a result, there is a problem that the power consumption of the motor 4 is increased in order to obtain a desired air volume.

  An object of this invention is to provide the centrifugal blower which can improve ventilation efficiency and can reduce power consumption.

  In order to achieve the above object, the present invention includes a sirocco fan having a plurality of radially arranged blades for sucking air in the axial direction and exhausting it in the circumferential direction, and covering the sirocco fan around the sirocco fan. An air that forms an annular air flow path and includes a blow-out portion provided on a peripheral surface and a casing having an intake port provided on the shaft of the sirocco fan, and is taken in from the intake port by rotation of the sirocco fan In the centrifugal blower, which flows from the low pressure side to the high pressure side of the air flow path and is guided to the blowing portion, the casing has an axial width with respect to the sirocco fan by a widening portion provided in the vicinity of the peripheral portion of the sirocco fan. And a shielding portion for shielding air flowing from the high pressure side to the low pressure side is provided on the inner surface side of the widening portion.

  According to this configuration, the air taken into the casing from the intake port by driving the sirocco fan is pushed out in the radial direction by the centrifugal force of the sirocco fan. The air in the peripheral portion is guided from the low pressure side to the high pressure side through the air flow passage widened by the widening portion, and is blown through the blowout portion. The air that has flowed through the air flow path and has reached the high pressure side is shielded by a shielding portion formed on the inner surface side of the widened portion, and inflow from the high pressure side to the low pressure side is prevented. The blow-out part may be constituted by a duct provided on the peripheral surface of the casing, or may be constituted by an opening provided on the peripheral surface of the casing.

  According to the present invention, in the centrifugal fan configured as described above, the widened portion overlaps the blade as viewed from the axial direction of the sirocco fan. According to this configuration, the tip of each blade is covered with the widened portion, and the airflow spreading in the axial direction from the peripheral portion of the sirocco fan flows into the air flow path from the widened portion.

  According to the present invention, in the centrifugal fan configured as described above, the widened portion includes a bell mouth that expands the diameter of the air inlet toward the outside. According to this configuration, outside air is smoothly guided to the intake port from a wide range.

  According to the present invention, in the centrifugal blower configured as described above, the shielding portion includes a rib projecting from the widened portion. According to this configuration, the high-pressure side air is shielded by the ribs protruding from the inner surface side of the widened portion, and inflow to the low-pressure side is prevented.

  In the centrifugal blower having the above-described configuration, the casing has an inclined surface that gradually expands the flow path on the low-pressure side in the axial direction, and the shielding portion extends in the axial direction from an end of the inclined surface. It is characterized by comprising wall surfaces. According to this configuration, the widened portion is shielded by the wall surface erected in the axial direction from the inclined surface, and the high-pressure side air is shielded to prevent inflow to the low-pressure side. The inclined surface may be formed by inclining the casing by bending, or an inclined protrusion may be provided on the inner surface of the casing.

  Further, in the centrifugal blower having the above-described configuration, the peripheral wall of the casing is bent to form a flow passage wall surface of the blowing portion, and a tongue portion close to the peripheral surface of the blade is provided to face the high pressure side. The tongue part and the shielding part are arranged in the same plane. According to this structure, the surrounding wall of a casing is bent by a tongue part and forms the wall surface of a blowing part. The tongue is close to the blade, and the air guided to the outside in the radial direction of the sirocco fan on the high-pressure side is prevented from flowing into the low-pressure side by the tongue. Circulate.

  According to the present invention, since the shielding portion is provided inside the widened portion that expands the axial width of the casing from the vicinity of the peripheral portion of the sirocco fan, the airflow spreading from the peripheral portion of the sirocco fan does not increase pressure loss. While being guided to the road, the high-pressure side air is prevented from flowing into the low-pressure side by the shielding portion. Therefore, the air blowing efficiency can be improved and the power consumption can be reduced.

  According to the present invention, since the widened portion is provided so as to overlap the blade when viewed from the axial direction of the sirocco fan, air is reliably guided from the peripheral portion of the sirocco fan to the air flow path via the widened portion. Accordingly, the air blowing efficiency can be further improved.

  Further, according to the present invention, the widened portion is formed by a bell mouth that expands the diameter of the intake port with the intake port facing outward, so that the intake amount can be increased and intake can be performed smoothly.

  Further, according to the present invention, since the shielding part is composed of the rib protruding from the widened part, it is possible to realize a shielding part that easily shields the airflow.

  Further, according to the present invention, since the shielding part is composed of the wall surface extending in the axial direction from the end of the inclined surface, the shielding part can be easily formed, and whirling in the vicinity of the shielding part can be prevented to further improve the blowing efficiency. it can.

  Moreover, according to this invention, since a shielding part continues to a tongue part and the high voltage | pressure side of a tongue part and a shielding part consists of the same surface, air can distribute | circulate smoothly through a blowing part and can improve ventilation efficiency.

  Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, the same parts as those in the conventional example shown in FIGS. 1 and 2 are a side sectional view and a plan view showing the centrifugal blower of the first embodiment. The centrifugal blower 1 has a sirocco fan 2 in which a plurality of blades 2a are provided radially.

  Both ends of each blade 2a in the axial direction are connected by a ring 2b and a back plate 2c, respectively. A boss 2d is formed at the center of the back plate 2c. A motor shaft 4a of the motor 4 is connected to the boss 2d. The motor 4 is fixed to the casing 3 by a fixing member 5. Thereby, the sirocco fan 2 is rotated by driving the motor 4.

  The sirocco fan 2 is covered with a casing 3, and an annular air flow path 3h is formed around it. The casing 3 is provided with an intake port 3a that is open in one axial direction. A bell mouth 3b (widened portion) is provided on the periphery of the air inlet 3a. A large amount of air can be smoothly sucked by the bell mouth 3b.

  On the back surface of the casing 3, a step portion 3 j (widened portion) is formed in the axial direction of the peripheral portion of the sirocco fan 2. The end of the bell mouth 3b on the sirocco fan 2 side and the surface of the step 3j facing the sirocco fan 2 are arranged close to the sirocco fan 2. Thereby, the air stagnating above or below the sirocco fan 5 in the axial direction can be reduced to improve the blowing efficiency.

  The casing 3 is widened in the axial direction with respect to the sirocco fan 2 portion by a bell mouth 3b and a step portion 3j. As a result, the airflow spreading in the axial direction from the periphery of the sirocco fan 2 is guided to the air flow path 3h without increasing the pressure loss. Furthermore, the end of the bell mouth 3b on the sirocco fan 2 side and the wall surface of the stepped portion 3j extending in the axial direction are provided so as to overlap the blade 2a when viewed from the axial direction. As a result, the tip of the blade 2a is covered with the widened portions of the bell mouth 3b and the stepped portion 3j, and the airflow spreading in the axial direction from the peripheral portion of the sirocco fan 2 can be reliably guided to the air flow path 3h.

  The peripheral wall of the casing 3 is formed in an Archimedean spiral, and the side with the smaller diameter is close to the blade 2a. A duct-shaped blowing portion 3c is provided to protrude on the side of the casing 3 having a large diameter. One side wall 3f of the blowout portion 3c is formed to extend from the peripheral wall of the casing 3 in the tangential direction. The other side wall 3g of the blowing portion 3c is formed by bending from the side of the peripheral wall of the casing 3 having a small diameter. As a result, a tongue portion 3e having a tongue shape in plan view is formed, and the inside of the casing 3 is separated into a low pressure side 6a and a high pressure side 6b by the tongue portion 3e. Further, the side wall 3g is provided so as to be inclined with respect to the side wall 3f by a predetermined angle θ so as to spread outward, so as to reduce the pressure loss of the exhaust gas.

  As shown in FIG. 3 (A-A cross section in FIG. 2), shielding portions 7a and 7b made of ribs are provided on the inner surface side of the bell mouth 3b and the step portion 3j. Thereby, the low pressure side 6a and the high pressure side 6b are partitioned at the upper end and lower end of the air flow path 3h that is wider in the axial direction than the sirocco fan 2. Further, the shielding portions 7a and 7b are formed on the same surface as the side wall 3g constituting the tongue portion 3e continuously to the tongue portion 3e.

  In the centrifugal blower 1 having the above configuration, when the motor 4 is driven, air flows into the casing 6 from the air inlet 2a by the rotation of the sirocco fan 2. The air flowing into the casing 6 is pushed out in the radial direction of the casing 3 by the centrifugal force of the sirocco fan 2, and is circulated as shown by an arrow A1 to flow from the low pressure side 6a to the high pressure side 6b. And it is exhausted from the exhaust port 3d through the blowing part 3c as shown by arrow A2.

  According to the present embodiment, the air that has reached the high pressure side 6a is restricted from wrapping around the low pressure side 6a by the tongue 3e close to the blade 25. Further, the airflow that is axially separated from the peripheral portion of the sirocco fan 2 is shielded by the shielding portions 7a and 7b and does not flow from the high pressure side 6a to the low pressure side 6a. Therefore, the ventilation efficiency of the centrifugal blower 1 can be improved. Further, since the shielding portions 7a and 7b are formed on the same surface as the side wall 3g constituting the tongue portion 3e continuously to the tongue portion 3e, the air reaching the high pressure portion 6b is smoothly guided to the blowing portion 3c without pressure loss. In addition, the air blowing efficiency can be further improved.

  FIG. 4 shows the relationship between the input of the motor 4 and the air volume by the centrifugal blower 1 of the present embodiment. The vertical axis represents the input (unit:%) of the motor 4, and the horizontal axis represents the air volume (unit: m / sec). Further, the centrifugal blower 1 of the present embodiment is indicated by D1 in the figure, and for comparison, the conventional example shown in FIGS. 8 and 9 is indicated by D2. According to the figure, the input of the motor 4 at the same air volume is lower than the conventional one, and the power consumption is reduced by improving the air blowing efficiency. Therefore, an air conditioner with low power consumption can be provided by mounting the centrifugal blower 1 of the present embodiment.

  Next, FIG. 5, FIG. 6 has shown the side sectional drawing and top view of the centrifugal air blower of 2nd Embodiment. FIG. 7 is a sectional view taken along line BB in FIG. For convenience of explanation, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are given the same reference numerals. In the present embodiment, inclined surfaces 8a and 8c are formed in the casing 3 to gradually expand the air flow path 3h on the low pressure side 6a in the axial direction. The inclined surfaces 8 a and 8 c are formed by bending the casing 3, but may be formed by inclined protrusions protruding from the inner surface of the casing 3.

  Then, shielding portions 8b and 8d made of wall surfaces extending in the axial direction from the end portions of the inclined surfaces 8a and 8c are provided in place of the shielding portions 7a and 7b (see FIG. 1) of the first embodiment. The shielding parts 8b and 8d are formed on the same surface as the side wall 3g along the side wall 3g of the blowing part 3c. Other parts are the same as those in the first embodiment.

  According to the present embodiment, the high-pressure side air is shielded by the shielding portions 8b and 8d and does not flow into the low-pressure side, and air blowing efficiency can be improved and power consumption can be reduced as in the first embodiment. Further, in the first embodiment, vortices are likely to be generated on the low pressure side of the rib-shaped shielding portions 7a and 7b (see FIG. 1). However, in this embodiment, the vortices can be eliminated by the inclined surfaces 8a and 8c, so Efficiency can be improved.

  In addition, in 1st, 2nd embodiment, although the blowing part 3c is formed with the duct, even if it opens part of the surrounding surface of the casing 3 and does not provide the tongue part 3e, the blowing part 3c is formed. Good. Moreover, although the surrounding wall of the casing 3 is formed in Archimedes spiral shape, you may form by a cylindrical surface.

These are side surface sectional drawings which show the centrifugal blower of 1st Embodiment of this invention. These are top views which show the centrifugal blower of 1st Embodiment of this invention. These are AA sectional drawing of FIG. These are figures which show the relationship between the motor input and air volume of the centrifugal blower of 1st Embodiment of this invention. These are side surface sectional drawings which show the centrifugal blower of 2nd Embodiment of this invention. These are top views which show the centrifugal blower of 2nd Embodiment of this invention. These are BB sectional drawing of FIG. These are sectional side views which show the conventional centrifugal blower. These are top views which show the conventional centrifugal blower.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Centrifugal blower 2 Sirocco fan 3 Casing 3a Inlet 3b Bell mouth (widening part)
3c Outlet part 3d Exhaust port 3e Tongue part 3h Air flow path 3j Step part (widening part)
7a, 7b, 8b, 8d Shielding part 8a, 8c Inclined surface 9 Space

Claims (6)

  A sirocco fan having a plurality of blades arranged radially and sucking in from the axial direction and exhausting in the circumferential direction, and forming an annular air passage around the sirocco fan and covering the sirocco fan, and on the circumferential surface An air outlet provided on the shaft of the sirocco fan, and air taken in from the air inlet by the rotation of the sirocco fan from the low pressure side to the high pressure side of the air flow path. In the centrifugal blower that circulates and is guided to the blowout part, the casing is expanded in the axial width with respect to the sirocco fan by a widened part provided in the vicinity of the peripheral part of the sirocco fan, and the low-pressure side from the high-pressure side A centrifugal blower characterized in that a shielding portion for shielding air flowing into the inside is provided on the inner surface side of the widened portion.   The centrifugal blower according to claim 1, wherein the widened portion overlaps the blade as viewed from the axial direction of the sirocco fan.   The centrifugal blower according to claim 1 or 2, wherein the widened portion is formed of a bell mouth that expands the diameter of the air inlet toward the outside.   The centrifugal blower according to any one of claims 1 to 3, wherein the shielding portion includes a rib projecting from the widened portion.   2. The casing according to claim 1, wherein the casing has an inclined surface that gradually expands the flow path on the low-pressure side in the axial direction, and the shielding portion includes a wall surface extending in the axial direction from an end portion of the inclined surface. The centrifugal blower according to any one of claims 3 to 4.   Bending the peripheral wall of the casing to form a flow passage wall surface of the blowing portion and providing a tongue portion close to the peripheral surface of the blade, the tongue portion facing the high pressure side and the shielding portion being in the same plane The centrifugal blower according to any one of claims 1 to 5, wherein the centrifugal blower is arranged.

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