JP2016033338A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve blowing efficiency while further reducing noise by a simple constitution, in a centrifugal blower.SOLUTION: A casing 18 constituting a centrifugal blower 10 has an external peripheral wall 24 which is formed into a spiral shape with respect to an external peripheral side of a fan 14 which is accommodated in the center. In the external peripheral wall 24, a first range S1 formed of an expanding angle α1 which is smaller than a substantially-constant expanding angle α is arranged in a former half portion between a winding starting end 24a joined to a linear part 26 and a winding terminal end 24b being a blow-out port 28 side, and a second range S2 formed of an expanding angle α2 which is larger than the substantially-constant expanding angle α is formed at a latter half portion. Then, in the former half portion, the external peripheral wall 24 is formed in a radial inside direction compared with the case that the external peripheral wall is formed of the substantially-constant expanding angle α, and in the latter half portion, the external peripheral wall is formed while being bulged to a radial outside direction compared with the case that the external peripheral wall is formed of the expanding angle α.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a centrifugal blower, and more particularly to a centrifugal blower used in an air conditioner mounted on a vehicle.

  2. Description of the Related Art Conventionally, a vehicular air conditioner employs a centrifugal blower that includes a fan that takes in inside air or outside air, a motor that rotates the fan, and a casing that surrounds the fan. In this centrifugal blower, a spiral passage is formed on the outer peripheral side of a fan having a plurality of blades, and air is taken in from a bell mouth of a casing opened in the axial direction of the fan under the rotational action of the fan. Air is swirled along the passage and discharged from the outlet of the straight portion protruding in the tangential direction from the circumferential direction of the passage. Further, the outer peripheral wall of the casing constituting the passage is formed to have a logarithmic spiral shape, and the spread angle is formed to be substantially constant from the start to the end of winding of the outer peripheral wall.

  In the centrifugal blower as described above, the pressure fluctuation increases due to the air flowing in a narrow area between the fan and the vicinity of the tongue portion joined to the straight portion, and the fan blade hits the air in the area, thereby causing noise. There is a concern that (NZ sound) is generated and the air blowing efficiency is lowered.

  Therefore, in order to solve the above-described noise generation and lowering of the blowing efficiency, for example, in the centrifugal blower disclosed in Patent Document 1, a portion where the expansion angle of the outer peripheral wall in the casing is set larger than substantially constant is set. By providing, the cross-sectional area of the passage is enlarged, the air flow in the passage is smoothed, the air blowing efficiency is improved, and the generation of noise is suppressed.

  Similarly, in the centrifugal blower according to Patent Document 2, the expansion angle of the outer peripheral wall of the casing is made constant within a predetermined range toward the rotation direction of the fan starting from the tongue, and then gradually increased. And the bulge part formed so that the said divergence angle may become fixed again is provided.

  Furthermore, in the centrifugal blower according to Patent Document 3, the outer peripheral wall of the casing is formed from a belt-shaped spring material, and one end portion is fixed and the other end portion can be wound by a winding mechanism. The expansion angle of the outer peripheral wall can be freely changed.

Japanese Patent Application Laid-Open No. 6-117397 JP 2011-149328 A JP 2004-270777 A

  However, in the centrifugal blower according to Patent Documents 1 and 2 described above, the outer peripheral wall of the casing is changed to increase the divergence angle between the start of winding and the end of winding, thereby suppressing noise and improving the blowing efficiency. However, there is a demand for further noise suppression and improvement of air blowing efficiency.

  Further, in the centrifugal blower of Patent Document 3, it is possible to change the spread angle by winding the outer peripheral wall using a winding mechanism, but it is difficult to accurately adjust the winding amount, When preparing a centrifugal blower, it is difficult to obtain the same performance with uniform spread angles. Further, the structure becomes complicated by providing the winding mechanism, which leads to an increase in size and an increase in weight.

  The present invention has been made in consideration of the above-described problems, and an object thereof is to provide a centrifugal blower capable of further improving the blowing efficiency with a simple configuration and further reducing noise. To do.

In order to achieve the above object, the present invention includes a casing having a spiral passage inside, a fan rotatably accommodated in the casing, and a drive source for rotating the fan. In the centrifugal blower provided with an outer peripheral wall whose radius changes logarithmically toward the outlet on the outer peripheral side,
The outer peripheral wall has a smaller divergence angle in the first half and a divergence angle in the second half compared to the case where the divergence angle is substantially constant from the beginning of winding to the end of winding, which is joined to the straight portion having the outlet. It is characterized by being formed to be large.

  According to the present invention, in the casing constituting the centrifugal blower, the outer peripheral wall provided on the outer peripheral side of the passage and whose radius changes in a logarithmic spiral shape is joined from the winding start to the winding end joined to the linear portion having the blower outlet. Up to this point, the first half is formed so that the divergence angle becomes smaller than that of a substantially constant case, and the second half is formed so that the divergence angle becomes larger.

  Therefore, the passage cross-sectional area in the vicinity of the tongue portion can be reduced with a simple configuration in which the divergence angle is made smaller in the first half portion on the winding start side of the outer peripheral wall than in the case where it is substantially constant. The secondary suction that sucks a part of the flowing air to the winding start side by the fan can be suppressed. As a result, the pressure fluctuation in the vicinity of the tongue is reduced, and the noise (NZ sound) is further reduced. be able to.

  At the same time, in the latter half portion, which is the winding end side of the outer peripheral wall with respect to the first half portion, the air is more smoothly moved to the outlet side in the passage with a simple configuration in which the divergence angle is made larger than that in the case where it is substantially constant. Therefore, it is possible to further improve the air blowing efficiency by increasing the amount of air sucked into the casing and increasing the air blowing amount accordingly.

  Furthermore, the outer peripheral wall may have a range in which the divergence angle is substantially constant between the first half portion and the second half portion.

  Furthermore, the first half portion is set within a range in which the winding angle is 120 ° to 170 ° from the base point to the winding end side from the site where the outer peripheral wall is joined to the tongue on the winding start side, It is preferable to set the latter half portion so that the winding angle is within a range of 240 ° to 320 ° with respect to the base point from the winding end side of the first half portion.

  Furthermore, the deviation between the divergence angle and the substantially constant divergence angle in the first half portion and the deviation between the divergence angle and the substantially constant divergence angle in the second half portion may be set to be the same.

  According to the present invention, the following effects can be obtained.

  That is, in the casing, the outer peripheral wall, which is provided on the outer peripheral side of the passage and has a logarithmically changing radius, extends from the beginning to the end of winding where it is joined to the straight portion having the air outlet, and the spread angle is at the first half. Can be reduced compared to the case of a substantially constant case, the passage cross-sectional area in the vicinity of the tongue can be reduced, the pressure fluctuation in the vicinity of the tongue can be reduced, and further noise reduction can be achieved. By forming the divergence angle so as to be larger than the case where the divergence angle is substantially constant, the air can be blown more smoothly into the outlet in the passage, so that it is possible to further improve the blowing efficiency. Become.

It is a partial cross section top view of the centrifugal air blower concerning an embodiment of the invention. It is a schematic plan view which shows the casing which comprises the centrifugal air blower of FIG. It is a characteristic diagram which shows the relationship between the winding angle in the centrifugal air blower of FIG. 1, and a divergence angle.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of a centrifugal blower according to the present invention will be given and described in detail below with reference to the accompanying drawings. In FIG. 1, reference numeral 10 indicates a centrifugal blower according to an embodiment of the present invention.

  As shown in FIG. 1, the centrifugal blower 10 includes a rotation drive source (drive source) 12 made of a motor and the like, a fan 14 that is rotationally driven under the drive action of the rotation drive source 12, A casing 18 having a spiral passage 16 provided so as to surround the outer periphery and through which air flows.

  The rotational drive source 12 is provided, for example, at a substantially lower center portion of the casing 18, and the rotation shaft 20 is connected to the central portion of the fan 14. And a plurality of blades 22 that are equally spaced apart from each other, and rotate integrally under the drive action of the rotary drive source 12. The fan 14 rotates clockwise (in the direction of arrow A) in FIG.

  As shown in FIGS. 1 and 2, the casing 18 has, for example, a passage 16 surrounding the outer peripheral side of the fan 14, and the outer peripheral wall 24 is formed in a logarithmic spiral shape. A straight portion 26 extending in the tangential direction from the winding end 24b of 24 is formed. And the blower outlet 28 opens in the edge part of the linear part 26 formed in linear form, and the air which flowed through the channel | path 16 is discharged outside.

  As shown in FIG. 2, the outer peripheral wall 24 has a radius from the tongue 30 that joins the winding start 24 a and the straight portion 26 to the center B of the fan 14 as R, and is rotated with the tongue 30 as a base point. When an angle at an arbitrary position in the direction (clockwise direction) (hereinafter referred to as a winding angle θ) is θ, an outer peripheral diameter of the fan 14 is D, and a spread angle is α, the following expression 1 is expressed. It is formed in a logarithmic spiral shape.

  Further, as shown in FIG. 2, the outer peripheral wall 24 has a winding angle θ1 on the winding end 24b side (rotation direction of the fan 14, direction of arrow C1) from the base line L connecting the center B of the fan 14 and the tongue portion 30. In the first range S1 up to this point, the first spread angle α1 is gradually reduced with respect to the substantially constant spread angle α (α1 <α). That is, the outer peripheral wall 24 is compared to the case where the divergence angle α is formed to be substantially constant (see the broken line shape in FIG. 2), and the center side of the fan 14 (radially inward, arrow) in the first range S1 by a predetermined distance E1 direction).

  Specifically, it is formed so that the vicinity of the first intermediate position F1 that is about half of the winding angle θ1 is located in the most radially inward direction, the winding start 24a side (arrow C2 direction) with respect to the first intermediate position F1, The winding end 24b side (in the direction of arrow C1) has a smooth curved shape that gradually expands outward in the radial direction so as to have a shape formed with a substantially constant spread angle α.

  That is, in the first range S1, the divergence angle α starts to gradually decrease from the winding start 24a side, becomes minimum at the first intermediate position F1, and gradually gradually again from the first intermediate position F1 toward the adjacent second range S2. It changes so that it may become large so that it may become a spread angle (alpha).

  The winding angle θ1 that defines the first range S1 is preferably set within a range of 120 ° to 170 °, for example (120 ° ≦ θ1 ≦ 170 °).

  In the above description, the first range S1 that forms the outer peripheral wall 24 at the spread angle α1 smaller than the spread angle α is set to start from the base line L. However, the present invention is not limited to this. After providing a range of the spread angle α by a predetermined range from L to the winding end 24b side, the first range S1 may be provided from the winding end 24b side of the range.

  Further, in the second range S2 up to the winding angle θ2 on the winding end 24b side (arrow C1 direction) with respect to the first range S1, the outer peripheral wall 24 has a second spread angle α2 larger than the substantially constant spread angle α. (Α2> α) and the spread angle α is substantially constant (see the broken line shape in FIG. 2), the side opposite to the center side of the fan 14 by a predetermined distance in the second range S2. It is formed so as to bulge (outward in the radius direction, arrow E2 direction).

  Specifically, the vicinity of the second intermediate position F2, which is about half the winding angle θ2, is formed so as to bulge most outward in the radial direction, and the winding start 24a side (arrow C2 direction) with respect to the second intermediate position F2. The winding end 24b side (in the direction of the arrow C1) has a smooth curved shape that gradually changes inward in the radial direction so that a substantially constant divergence angle α is formed.

  That is, in the second range S2, the divergence angle α gradually starts to increase from the winding start 24a side, reaches the maximum at the second intermediate position F2, and gradually gradually again from the second intermediate position F2 toward the adjacent third range S3. It changes so that it may become small so that it may become a spread angle (alpha).

  The winding angle θ2 that defines the second range S2 with respect to the winding angle θ1 is preferably set within a range of 120 ° to 150 °, for example (120 ° ≦ θ2 ≦ 150 °). In other words, the range formed by the second divergence angle α2 is in the range of 240 ° to 320 ° toward the winding end 24b with respect to the base line L.

  Further, as shown in FIG. 3, the divergence angle α1 in the first range S1 and the divergence angle α2 in the second range S2 are set so that the deviation from the substantially constant divergence angle α is the same (| α −α1 | = | α−α2 |). For example, when the substantially constant spread angle α is 4 ° and the spread angle α1 is 3.8 °, the spread angle α2 is set to 4.2 ° (deviation 0.2 °).

  Furthermore, in the third range S3 that is on the winding end 24b side (in the direction of the arrow C1) with respect to the second range S2, it is formed up to the joining portion with the linear portion 26 that becomes the winding end 24b at a substantially constant spread angle α. .

  In the above description, the boundary between the two ranges between the first range S1 formed by the spread angle α1 smaller than the substantially constant spread angle α and the second range S2 formed by the large spread angle α2. The spread angle α is formed only at the position of the winding angle θ2, which is, for example, formed with a substantially constant spread angle α between the first range S1 and the second range S2 by a predetermined range. You may make it provide a site | part (range).

  That is, the outer peripheral wall 24 sets the spread angle to be smaller in the first range S1 on the winding start 24a side (α1), and the spread angle is reversed in the second range S2 on the winding end 24b side from the first range S1. Is set large (α2), and the divergence angle is set to be substantially constant (α) in the winding start 24a side of the first range S1, between the first range S1 and the second range S2, and in the third range S3. doing.

  In other words, the outer peripheral wall 24 has a portion formed with a small divergence angle α1 in the first half portion on the winding start 24a side (arrow C2 direction), and on the other hand, on the winding end 24b side (arrow C1 direction). The latter half has a portion formed with a large divergence angle α2.

  The centrifugal blower 10 according to the embodiment of the present invention is basically configured as described above. Next, its operation and effects will be described.

  First, the rotary drive source 12 is driven based on a control signal from a controller (not shown), and the fan 14 rotates under the drive action of the rotary drive source 12, thereby opening an air intake opening (not shown) above the casing 18. Air) is sucked into the fan 14 from the inside.

  Then, the air that has turned in the clockwise direction under the rotational action of the fan 14 passes between the plurality of blades 22 and is sent to the outer peripheral side passage 16, and along the passage 16 to the blowout port 28. It is guided.

  As described above, in the present embodiment, in the casing 18 constituting the centrifugal blower 10, the outer peripheral wall 24 formed in a logarithmic spiral is from the winding start 24a joined to the straight portion 26 to the winding end 24b side. Since the cross-sectional area of the passage 16 in the vicinity of the tongue portion 30 can be reduced by reducing the divergence angle within a predetermined range (within the first range S1) to be substantially constant (α1 <α), a straight line Secondary suction that sucks part of the air flowing through the portion 26 to the air outlet 28 by the fan 14 and starts to wind toward the side 24a can be suppressed. As a result, the pressure fluctuation in the vicinity of the tongue 30 is reduced, so that the noise (NZ sound) generated in the vicinity of the tongue 30 can be further reduced.

  Further, in the casing 18, by increasing the divergence angle with respect to the first half portion (second range S <b> 2) on the side of the winding end 24 b to a substantially constant angle (α <b> 2> α), air is passed through the passage 16. Since the air can be blown more smoothly toward the air outlet 28, the amount of air sucked into the casing 18 through the air intake port (not shown) can be increased, and the air amount can be increased accordingly. it can. As a result, it is possible to further improve the blowing efficiency in the centrifugal blower 10.

  That is, in the outer peripheral wall 24 of the casing 18, a first range S1 formed with a spread angle α1 smaller than a substantially constant spread angle α is provided in the first half portion on the winding start 24a side, and from the first range S1. With the simple configuration of providing the second range S2 formed with the spread angle α2 larger than the substantially constant spread angle α in the latter half portion on the winding end 24b side, noise generated in the vicinity of the tongue 30 can be further reduced. Further, it is possible to further improve the blowing efficiency. Furthermore, an increase in size and an increase in weight, which have been a concern with conventional centrifugal fans, can be suitably avoided.

  Further, in the vicinity of the air outlet 28 of the casing 18, since the expansion angle α is changed to be substantially constant in the third range S <b> 3 where the winding ends and is connected to the linear portion 26, for example, the centrifugal blower 10 is When connecting to a vehicle air conditioner (not shown) via the air outlet 28, it is possible to connect with a connection portion shape that is substantially the same as that of a conventional centrifugal blower formed with a substantially constant spread angle α. It becomes possible. In other words, even when the divergence angle in the middle of the outer peripheral wall 24 is changed, the shape of the straight portion 26 on the downstream side is not changed. There is no need to change, which is preferable.

  In addition, the centrifugal blower according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Centrifugal blower 12 ... Rotary drive source 14 ... Fan 16 ... Passage 18 ... Casing 24 ... Outer peripheral wall 26 ... Linear part 28 ... Outlet S1 ... 1st range S2 ... 2nd range S3 ... 3rd range (alpha), (alpha) 1, α2 ... Spreading angle θ1, θ2 ... Winding angle

Claims (4)

A casing having a spiral passage inside, a fan housed rotatably in the casing, and a drive source for rotating the fan, and a logarithmic spiral toward the outlet on the outer peripheral side of the passage In a centrifugal blower having an outer peripheral wall whose radius changes in a shape,
The outer peripheral wall is smaller in the first half portion than in the second half portion when the spread angle is substantially constant from the beginning of winding to the end of winding joined to the straight portion having the outlet. A centrifugal blower characterized in that the divergence angle is increased. The centrifugal blower according to claim 1, wherein
The centrifugal blower according to claim 1, wherein the outer peripheral wall has a range in which the divergence angle is substantially constant between the front half part and the rear half part. In the centrifugal blower according to claim 1 or 2,
The first half portion is set within a range in which the winding angle is 120 ° to 170 ° from the base point toward the winding end side, with a portion where the outer peripheral wall is joined to the tongue portion on the winding start side as the base point, The second half part is set so that the winding angle may be within a range of 240 ° to 320 ° with respect to the base point from the winding end side of the first half part. The centrifugal blower according to any one of claims 1 to 3,
The deviation between the divergence angle and the substantially constant divergence angle in the first half portion and the deviation between the divergence angle and the substantially constant divergence angle in the second half portion are set to be the same. Centrifugal blower to do.

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