JP5131326B2 - Centrifugal blower - Google Patents

Description

  The present invention relates to a centrifugal blower used for an air conditioner such as an air cleaner or a fan coil.

  Conventionally, a centrifugal blower includes a casing having a suction port and a blower outlet, and a centrifugal multi-blade fan disposed in the casing so as to face the suction port (Japanese Patent Laid-Open No. 2002-257091). Gazette: see Patent Document 1).

  The fan has a plurality of blades arranged in an annular shape, sucks air from the fan's axial suction side, and blows out the air in a centrifugal direction from between the blades.

  The casing has a tongue on the blowing side of the fan, and the tongue prevents the air blown from the fan from flowing backward to the suction side of the fan.

  By the way, in the conventional centrifugal blower, the air sucked from the suction port of the casing is sucked into the central portion of the fan and blown out from the fan in the centrifugal direction. And since the air blown in the centrifugal direction from the blades facing the outlet of the casing directly hits the tongue in a laminar flow state, the Nz sound caused by the interference between the tip of the fan blade and the tongue of the casing There has been a problem that (a peak sound having a frequency of the product Nz of the number N of fan blades and the rotation number z) occurs.

JP 2002-257091 A

  Then, the subject of this invention is providing the centrifugal air blower which can suppress generation | occurrence | production of Nz sound resulting from interference with the tongue part of a casing, and the front-end | tip of a fan.

In order to solve the above problems, the centrifugal fan of the present invention is
A casing having a suction port and an air outlet and having a tongue portion;
A centrifugal multiblade fan disposed in the casing facing the suction port, and
A first straight line that is perpendicular to the rotational axis of the fan and is in contact with the circumferential tip of the fan at the tongue, and perpendicular to the rotational axis of the fan and the first straight line as viewed from the rotational axis of the fan. A specific area surrounded by a second straight line forming 90 degrees in the direction opposite to the tongue, a virtual outer circle in contact with the tip of the fan, and a virtual inner circle having a radius half the radius of the virtual outer circle Inside, a baffle plate is provided so as to face the suction side in the rotation axis direction of the fan ,
Between the first straight line and a third straight line that is orthogonal to the rotational axis of the fan and forms 60 degrees in the direction opposite to the tongue with respect to the first straight line when viewed from the rotational axis direction of the fan, The baffle plate is arranged .

  According to the centrifugal blower of the present invention, since the baffle plate is provided so as to face the suction side of the fan in the rotation axis direction, the air sucked from the suction port of the casing is placed on the suction side of the fan. The air flow is disturbed by hitting the baffle plates arranged to face each other. That is, a turbulent flow is generated on the baffle plate.

  And since the said baffle plate is provided in the said specific area | region, the air of the turbulent flow state which generate | occur | produced in the baffle plate can be directly applied to a tongue part from a fan.

  In this way, by applying the turbulent air generated by the baffle plate to the tongue, the laminar air blown from the fan is prevented from directly hitting the tongue, Generation of Nz sound due to interference with the tip of the fan can be suppressed.

Further , since the baffle plate is located between the first straight line and the third straight line, the turbulent air generated in the baffle plate can be reliably applied directly to the tongue. . Therefore, even if the baffle plate is made small or the number of baffle plates is reduced, the generation of Nz sound can be suppressed.

  In the centrifugal blower according to the embodiment, when viewed from the direction of the rotation axis of the fan, the end of the tongue is connected to the inner surface of the casing on the side facing the tongue while being orthogonal to the rotation axis of the fan. The baffle plate is disposed between the fourth straight line passing through the midpoint of the shortest distance among the line segments and the third straight line.

  According to the centrifugal blower of this embodiment, since the baffle plate is located between the third straight line and the fourth straight line, the turbulent air generated in the baffle plate is more reliably prevented. Can be applied directly to the tongue. Therefore, even if the baffle plate is made small or the number of baffle plates is reduced, the generation of the Nz sound can be more reliably suppressed.

Moreover, in the centrifugal blower of one embodiment,
A lattice member is provided on the suction side of the fan,
The lattice member has a lattice in a region between an edge on the tongue portion side of the baffle plate and the first straight line when viewed from the rotation axis direction of the fan. It is coarser than the lattice on the side opposite to the part.

  According to the centrifugal blower of this embodiment, the lattice member has a lattice in a region between the edge on the tongue side of the baffle plate and the first straight line when viewed from the rotation axis direction of the fan. Even if the air flow is blocked by the baffle plate, the edge on the tongue side of the baffle plate and the first straight line are rougher than the lattice on the opposite side of the tongue from the rotation axis of the fan. Air can be sucked in through the coarse lattice between them, and windage damage can be prevented.

  Also, a large turbulent flow is generated by mixing the air flow passing through the coarse lattice between the edge on the tongue side of the baffle plate and the first straight line and the turbulent air flow generated by hitting the baffle plate. Can be generated. And the air of this big turbulent flow state can be applied to a tongue part, and generation | occurrence | production of Nz sound can be suppressed further.

  In one embodiment, the fan is a sirocco fan.

  According to the centrifugal blower of this embodiment, when a sirocco fan is used as the fan, generation of Nz sound can be more effectively suppressed.

  According to the centrifugal blower of the present invention, since the baffle plate is provided in the specific area so as to face the suction side in the rotation axis direction of the fan, the interference between the tongue of the casing and the tip of the fan. It is possible to suppress the generation of Nz sound due to the noise.

It is the perspective view seen from the front side of the air cleaner using the centrifugal blower of this invention. It is the perspective view seen from the back side of a centrifugal blower. It is the perspective view seen from the back side of the centrifugal blower of the state which removed the fan. It is a simplified sectional view of a centrifugal blower. It is effect | action explanatory drawing explaining the effect | action of a centrifugal blower.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1: has shown the perspective view seen from the front side of the air cleaner using the centrifugal blower of this invention. As shown in FIG. 1, the air cleaner has a main body casing 1 and a centrifugal blower 2 disposed in the main body casing 1. In the figure, the arrow F direction is the front direction (front direction), and the arrow B direction is the back direction (rear direction).

  In the main body casing 1, a filter unit (not shown) is arranged in front of the centrifugal blower 2. Then, external air is sucked from the front surface of the main casing 1 by the action of the centrifugal blower 2. The air sucked into the main casing 1 passes through the filter unit, is cleaned by removing dust and bacteria, and then passes through the centrifugal blower 2 to the outside through the outlet 1a of the main casing 1. Blown out.

  As shown in FIGS. 1, 2, and 3, the centrifugal blower 2 includes a casing 10 and a centrifugal multiblade fan 20 disposed in the casing 10. 2 and 3 are perspective views as seen from the back direction (arrow B direction), and FIG. 3 shows a state where the fan 20 is removed.

  The casing 10 includes a suction port 11 that opens forward and an air outlet 12 that opens upward. The suction port 11 is called a so-called bell mouth and is provided only on one side of the casing 10, so the centrifugal blower 2 is a so-called single suction type centrifugal blower.

  The fan 20 is disposed to face the suction port 11. That is, one end surface of the fan 20 in the direction of the rotation shaft 20 a is disposed so as to face the suction port 11. The fan 20 is a sirocco fan and has a plurality of blades 21 arranged in an annular shape at an equal pitch. The fan 20 rotates in the direction of arrow A in FIG. 2, thereby sucking air from the suction side of the fan 20 in the direction of the rotation axis 20 a and blowing this air from between the blades 21 in the centrifugal direction.

  The casing 10 has a tongue 13 on the outlet side of the fan 20. The tongue 13 is located in the rotation direction (A direction) of the fan 20 on the inner surface of the casing 10 and protrudes in the direction opposite to the rotation direction of the fan 20. The tongue 13 prevents the air blown from the fan 20 from flowing backward to the suction side of the fan 20.

  A lattice member 40 is provided on the suction side of the fan 20 in the direction of the rotation shaft 20a. The lattice member 40 is attached to the suction port 11 of the casing 10. The lattice member 40 prevents the hand from being inserted into the suction port 11 and prevents the hand from contacting the fan 20.

  A baffle plate 30 is provided so as to face the suction side of the fan 20 in the direction of the rotation shaft 20a. The baffle plate 30 partially blocks the flow of air sucked into the fan 20. The baffle plate 30 is attached to the side surface of the lattice member 40 on the fan 20 side.

  As shown in FIG. 4, the baffle plate 30 is in a specific area Z surrounded by the first straight line L <b> 1, the second straight line L <b> 2, the virtual outer circle Co, and the virtual inner circle Ci as viewed from the direction of the rotation axis 20 a of the fan 20. Is located. In FIG. 4, the specific region Z is indicated by hatching for easy understanding.

  The first straight line L <b> 1 is orthogonal to the rotation axis 20 a of the fan 20 and is in contact with the tip of the tongue 13 in the circumferential direction of the fan 20. The second straight line L2 is orthogonal to the rotational axis 20a of the fan 20 and forms 90 degrees in the direction opposite to the tongue 13 with respect to the first straight line L1. The virtual outer circle Co is in contact with the front end of the fan 20 (the front end of the blade 21) around the rotation axis 20a of the fan 20. The virtual inner circle Ci has a radius that is half the radius of the virtual outer circle Co with the rotation axis 20a of the fan 20 as the center.

  Specifically, the baffle plate 30 is located between the first straight line L1 and the third straight line L3 when viewed from the direction of the rotation axis 20a of the fan 20. The third straight line L3 is orthogonal to the rotation axis 20a of the fan 20 and forms 60 degrees in the direction opposite to the tongue 13 with respect to the first straight line L1.

  More specifically, the baffle plate 30 is located between the third straight line L3 and the fourth straight line L4 when viewed from the direction of the rotation axis 20a of the fan 20. The fourth straight line L4 is perpendicular to the rotation axis 20a of the fan 20 and is the line segment Lm that forms the shortest distance among the line segments that connect the tip of the tongue 13 and the inner surface of the casing 10 facing the tongue 13. Passes through the midpoint M.

  The baffle plate 30 is positioned on the inner side in the radial direction of the virtual root circle Cm in contact with the root of the blade 21 of the fan 20 so as to touch the virtual root circle Cm. The virtual root circle Cm is located between the virtual outer circle Co and the virtual inner circle Ci with the rotation axis 20a of the fan 20 as the center. The size of the suction port 11 of the casing 10 is substantially equal to the virtual root circle Cm.

  As shown in FIGS. 3 and 4, the lattice member 40 is a lattice in a region between the edge on the tongue 13 side of the baffle plate 30 and the first straight line L <b> 1 when viewed from the direction of the rotation axis 20 a of the fan 20. However, it is rougher than the lattice on the side opposite to the tongue 13 with respect to the rotating shaft 20a of the fan 20. That is, the lattice member 40 has the rough hole portion 41 on the first straight line L1 side with respect to the edge of the baffle plate 30 on the tongue portion 13 side. The rough hole portion 41 is rougher than the lattice at the bottom of the lattice member 40.

  The rough hole portion 41 includes a line segment perpendicular to the rotation axis 20a of the fan 20 and in contact with the edge on the tongue 13 side of the baffle plate 30 as viewed from the direction of the rotation axis 20a of the fan 20, and the rotation axis 20a of the fan 20. Is located within a region surrounded by a fifth straight line L5 that is 30 degrees in the direction of the tongue 13 with respect to the first straight line L1, a virtual inner circle Ci, and a virtual root circle Cm.

  The rough hole portion 41 is provided in the upper portion of the lattice member 40. On the upper portion of the lattice member 40, a partition wall (not shown) that prevents hand insertion is disposed. For this reason, even if the rough hole portion 41 is provided in the lattice member 40, the partition wall does not insert a hand into the rough hole portion 41.

  Next, the operation of the centrifugal blower 2 configured as described above will be described.

  As shown in FIGS. 1 and 5, the air sucked from the suction port 11 of the casing 10 hits a baffle plate 30 disposed so as to face the suction side of the fan 20, and this air flow is disturbed. The That is, a turbulent flow is generated in the baffle plate 30.

  And since the said baffle plate 30 is provided in the said specific area Z, the air of the turbulent flow state which generate | occur | produced in the baffle plate 30 can be directly applied to the tongue part 13 from the fan 20. FIG. In FIG. 5, turbulent air is indicated by hatching for easy understanding.

  Thus, by applying the turbulent air generated in the baffle plate 30 to the tongue 13, the laminar air blown from the fan 20 is prevented from directly hitting the tongue 13, and the casing The generation of Nz sound due to the interference between the ten tongues 13 and the tip of the fan 20 can be suppressed.

  When the baffle plate 30 is provided outside the specific region Z, the flow of air sucked into the blades 21 facing the air outlet 12 of the casing 10 is not disturbed. The generation of Nz sound cannot be suppressed.

  Further, since the baffle plate 30 is located between the third straight line L3 and the fourth straight line L4, the turbulent air generated in the baffle plate 30 is more directly directly applied to the tongue 13. You can guess. In other words, the baffle plate 30 is disposed at a position where the turbulent air generated by the baffle plate 30 directly hits the tongue portion 13. Therefore, even if the baffle plate 30 is made small or the number of the baffle plates 30 is reduced, the generation of the Nz sound can be more reliably suppressed.

  In the case where the baffle plate 30 is provided between the first straight line L1 and the third straight line L3, the Nz sound is generated as compared with the case where the baffle plate 30 is provided between the second straight line L2 and the third straight line L3. Generation can be remarkably suppressed. Further, when the baffle plate 30 is provided between the third straight line L3 and the fourth straight line L4, Nz sound is generated compared to the case where the baffle plate 30 is provided between the first straight line L1 and the fourth straight line L4. Can be remarkably suppressed.

  Further, since the baffle plate 30 is disposed inside the root of the blade 21 of the fan 20 (inside the virtual root circle Cm) so as to be in contact with the virtual root circle Cm, air is directly applied to the tongue portion 13. With respect to the blade 21 that contributes to blowing, a baffle plate 30 can be disposed in the flow path of the air sucked into the blade 21, and the turbulent air generated in the baffle plate 30 is directly and effectively applied to the tongue portion 13. Can be applied.

  Further, the lattice member 40 has a lattice (rough hole portion 41) in a region between the edge on the tongue portion 13 side of the baffle plate 30 and the first straight line L1 when viewed from the direction of the rotation axis 20a of the fan 20. Since it is coarser than the lattice on the opposite side of the tongue 13 to the rotating shaft 20a of the fan 20, even if the air flow is blocked by the baffle plate 30, air can be sucked from the rough hole 41. Can prevent wind damage. Further, a large turbulent flow can be generated by mixing the air flow passing through the rough hole portion 41 and the turbulent air flow generated by hitting the baffle plate 30. And the air of this big turbulent flow state can be applied to the tongue part 13, and generation | occurrence | production of Nz sound can be suppressed further.

  Further, when the sirocco fan 20 is used as the fan 20, the generation of Nz sound can be suppressed more effectively.

  In addition, this invention is not limited to the above-mentioned embodiment. For example, the baffle plate may be positioned within a specific area and between the second straight line and the third straight line, and the turbulent air generated in the baffle plate is blown out of the fan by hitting the tongue. The generated laminar air can be prevented from directly hitting the tongue, and the generation of Nz sound can be suppressed.

  Further, the baffle plate may be positioned in a specific area and between the first straight line and the fourth straight line, and the air in the turbulent state generated by the baffle plate is surely applied directly to the tongue. Can do. Therefore, even if the baffle plate is made small or the number of baffle plates is reduced, the generation of Nz sound can be suppressed.

  In addition, the rough hole portion of the lattice member may be provided only in the region between the edge on the tongue side of the baffle plate and the first straight line, and generation of Nz noise can be further suppressed while preventing windage loss. .

  In addition to the single suction type centrifugal blower, the centrifugal blower may be used for a double suction type centrifugal blower. In the case of this double suction type centrifugal blower, baffle plates are provided on the suction sides on both sides in the rotational axis direction of the fan.

  In addition to the sirocco fan, a centrifugal multiblade fan such as a turbo fan may be used as the fan. Of course, the fan blades may be arranged at unequal pitches.

  Moreover, you may use a centrifugal air blower in general air conditioners other than an air cleaner, such as a dehumidifier, a humidifier, an air conditioner (fan coil), or an apparatus provided with two or more of these functions.

DESCRIPTION OF SYMBOLS 1 Main body casing 2 Centrifugal blower 10 Casing 11 Suction inlet 12 Outlet 13 Tongue part 20 Fan 20a Rotating shaft 21 Blade 30 Baffle plate 40 Lattice member 41 Rough hole part L1 1st straight line L2 2nd straight line L3 3rd straight line L4 4th straight line L5 5th straight line Lm Line forming the shortest distance M Midpoint Co Virtual outer circle Ci Virtual inner circle Cm Virtual root circle Z Specific area

Claims (4)

A casing (10) having a suction port (11) and an outlet (12) and having a tongue (13);
A centrifugal multi-blade fan (20) disposed in the casing (10) facing the suction port (11);
When viewed from the direction of the rotation axis (20a) of the fan (20), the second direction is perpendicular to the rotation axis (20a) of the fan (20) and contacts the tip of the tongue (13) in the circumferential direction of the fan (20). A first straight line (L1) and a second straight line (90 ° perpendicular to the rotation axis (20a) of the fan (20) and 90 degrees in the direction opposite to the tongue (13) with respect to the first straight line (L1). L2), a specific area (Z) surrounded by a virtual outer circle (Co) in contact with the tip of the fan (20) and a virtual inner circle (Ci) having a radius half the radius of the virtual outer circle (Co). ), A baffle plate (30) is provided so as to face the suction side in the direction of the rotation axis (20a) of the fan (20) ,
When viewed from the direction of the rotational axis (20a) of the fan (20), the direction is perpendicular to the rotational axis (20a) of the fan (20) and in the direction opposite to the tongue (13) with respect to the first straight line (L1). A centrifugal blower characterized in that the baffle plate (30) is disposed between a third straight line (L3) forming 60 degrees and the first straight line (L1) . In the centrifugal blower according to claim 1 ,
When viewed from the direction of the rotation axis (20a) of the fan (20), the side is orthogonal to the rotation axis (20a) of the fan (20) and faces the tip of the tongue (13) and the tongue (13). Between the fourth straight line (L4) passing through the midpoint (M) of the line segment (Lm) forming the shortest distance among the line segments connecting the inner surface of the casing (10) and the third straight line (L3) And the baffle plate (30). In the centrifugal blower according to claim 1 or 2 ,
A lattice member (40) is provided on the suction side of the fan (20),
The lattice member (40) is formed between the edge on the tongue (13) side of the baffle plate (30) and the first straight line (L1) when viewed from the direction of the rotation axis (20a) of the fan (20). The centrifugal blower characterized in that the lattice in the area between them is coarser than the lattice on the side opposite to the tongue (13) with respect to the rotational axis (20a) of the fan (20). In the centrifugal blower according to any one of claims 1 to 3 ,
Centrifugal blower characterized in that the fan (20) is a sirocco fan (20).