JP4500038B2 - Centrifugal multi-blade fan - Google Patents

Description

  The present invention relates to a centrifugal multiblade fan, and more particularly to a multiblade fan having an improved blade portion and suitable for a vehicle air conditioner or the like.

  Conventionally, the performance of a blower related to the air blowing capacity and noise is greatly influenced by the fan blade shape, the casing scroll shape, and the like, and it is necessary to sufficiently consider them in designing.

  In a multiblade fan, the length of each blade in the air flow direction is formed to be relatively short, so that an air flow along the blade is difficult to form, and a vortex is likely to occur due to separation of the air flow. The vortex noise resulting from this separation is the main noise in the multiblade fan. As a proposal to reduce such noise, for example, a proposal of an airfoil fan that reduces vortex noise due to separation of airflow from a blade by making the cross-sectional area of the blade into a blade shape has been made (for example, Patent Document 1).

  However, in the proposal as in the above-mentioned Patent Document 1, the air flow is biased from the suction surface of the blade to the pressure surface side of another blade adjacent to the operating point of the low pressure loss. There is a risk that shear flow may occur in the wake. In order to solve such a problem, a method of forcibly preventing the air flow bias by narrowing the interval between the radially outer ends of the blades can be considered. Since the relative speed increases at the end, the pressure recovery becomes insufficient, so that the blowing performance and noise characteristics may be deteriorated at the operating point of high pressure loss.

  In order to solve the above problems, the applicant has made a proposal as shown in FIG. 5 (patent document 2), although the application has not yet been disclosed. In FIG. 5, reference numeral 100 denotes a main blade. A plurality of main blades 100 are arranged in the circumferential direction around the rotation axis. Further, an auxiliary blade group constituted by the auxiliary blade 101 is provided on the radially outer side of the main blade group constituted by the main blade 100. Further, the auxiliary blade 101 is disposed in an air flow formed between adjacent main blades.

  In the above proposal, air flows along the pressure surface 103 and the suction surface 102 of the main blade 100 by the rotation of the fan. At this time, the air flowing along the suction surface 102 tends to be separated from the suction surface 102 toward the pressure surface 103 of the adjacent blade, and a shear flow is formed behind the outer end 104 of the main blade 100. There is a risk. However, if the auxiliary blade 101 as described above is provided, the air that has passed through the main blade 100 flows along the positive pressure surface 105 and the negative pressure surface 106 of the auxiliary blade 101. Since the generation of the shear flow behind the main blade 100 is reliably suppressed, the air blowing performance and noise characteristics are improved.

However, in the proposal as described in Patent Document 2, the blades 100 and 101 made of resin or the like, in particular, the auxiliary blade 101 may be deformed by the rotation of the fan. In some cases, the auxiliary blade 101 is indicated by a dotted line in the drawing. There is a possibility that the main blade 100 deforms and rarely contacts the radially outer end 104.
JP 60-156997 A

Japanese Patent Application No. 2002-215490

  Accordingly, an object of the present invention is to provide a multi-blade fan in which auxiliary blades are arranged on the outer side in the radial direction of the main blade. The object is to provide a multi-blade fan that can reliably improve the air blowing performance and noise performance at low cost.

In order to solve the above problems, a multiblade fan according to the present invention includes a multiblade fan section having a plurality of blades arranged in a circumferential direction around a rotation axis, and the rotation of the multiblade fan section causes each blade to move between the blades. In the multiblade fan that sucks air from the inner diameter end side and discharges air from the outer diameter end side, a plurality of main blades are arranged radially inside, and the air between the main blades is arranged radially outside An auxiliary blade is arranged inside the flow, and a reinforcing rib for connecting the main blade and the auxiliary blade is provided , and the radial outer end of the main blade and the radial inner end of the auxiliary blade are connected by the reinforcing rib. consisting of those wherein the are. In such a configuration, since the main blade and the auxiliary blade are connected by the reinforcing rib, the deformation strength of both blades, particularly the auxiliary blade, is improved. For this reason, the inconvenience that the auxiliary blade is deformed to the pressure surface side of the main blade is surely prevented, so that the original function of the auxiliary blade is exhibited, and the separation of the air flow and the generation of the shear flow are reliably suppressed. The Therefore, the ventilation performance and noise characteristics of the multiblade fan are reliably improved.

  The location of the reinforcing ribs is not particularly limited. However, if one reinforcing rib is provided at the center in the longitudinal direction of both blades (the axial direction of the fan), the main blade can be formed with a simple mold structure. The auxiliary blade can be easily formed integrally. A plurality of reinforcing ribs can be arranged in the longitudinal direction.

In addition, since the reinforcing ribs are disposed at the radially outer end of the main blade and the radially inner end of the auxiliary blade, the directivity to the auxiliary blade (auxiliary blade) is suppressed while suppressing the ventilation resistance of the air that has passed through the main blade. Directivity). Also, both blades can be connected at the shortest distance.

  Further, it is preferable that the radially inner end of the auxiliary blade is disposed on the inner side in the fan radial direction than the radially outer end of the main blade. According to such a configuration, the deviation of the air flow toward the pressure surface side of the main blade due to the separation of the air after passing through the main blade can be suppressed early and reliably on the upstream side.

  In the multiblade fan according to the present invention, the main blade and the auxiliary blade provided on the outer side in the radial direction are connected to each other by the reinforcing rib, so that deformation of both the main blade and the auxiliary blade, particularly the auxiliary blade, can be effectively performed. Can be prevented. Therefore, the original function of the auxiliary blade is ensured, and the air blowing characteristics and noise characteristics can be improved more reliably.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a multiblade fan according to an embodiment of the present invention. 1 and 2, reference numeral 1 denotes the entire multi-blade fan, and the multi-blade fan 1 has a multi-blade fan section 3 having a large number of main blades 2 and auxiliary blades 9. A large number of blades 2 and 9 are arranged around the rotation axis 4 in the circumferential direction. A disk-shaped drive plate 5 is provided at the end of the blades 2 and 9 on the side opposite to the air suction side, and is connected to all the blades 2 and 9. A boss portion 6 is formed at the center of the drive plate 5, and the rotation shaft 4 is mounted in the boss portion 6, and the drive plate 5 and all the blades 2, 9 are moved in a predetermined direction (by rotation of the rotation shaft 4). It is rotated in the direction of the arrow in FIG. An annular connection ring 7 is provided at the air suction side end of the blades 2, 9. The connection ring 7 connects all the blades 2, 9 to each other and plays a role of reinforcement.

  As shown in FIGS. 3 and 4, a plurality of main blades 2 and auxiliary blades 9 are provided in the circumferential direction, and the main blade 2 that mainly sucks the inside and outside air is radially inward, and the radially outer side, that is, The auxiliary blade 9 is provided in the air flow between the main blades 2, in other words, in the air passage 17. In this embodiment, both blades are arranged such that the radial inner end 13 of the auxiliary blade 9 is on the inner side than the radial outer end 12 of the main blade 2. Note that 11 indicates the radially inner end of the main blade 2, and 14 indicates the radially outer end of the auxiliary blade 9.

  Both the main blade 2 and the auxiliary blade 9 have a blade shape in which the blade thickness increases gradually and then gradually decreases. In the present embodiment, the main blade 2 is formed larger in thickness, warpage, and chord length than the auxiliary blade 9, and is designed so that the suction capability of the main blade 2 is increased.

  The main blade 2 and the auxiliary blade 9 are connected by a reinforcing rib 10. In this embodiment, as shown in FIG. 2, the reinforcing rib 10 is provided at one location in the substantially central portion in the longitudinal direction of the blades 2 and 9. If the reinforcing ribs 10 are arranged in the above-described positional relationship, the blade 2 and the blade 9 can be integrally formed with a simple mold that does not require a slide structure. Therefore, the substantial increase in the number of parts and the number of manufacturing steps can be prevented, so that the cost increase can be significantly suppressed. The reinforcing rib 10 may be formed separately from the blades 2 and 9. If the reinforcing rib 10 and the blades 2 and 9 are configured separately, the present invention can be easily applied to an existing apparatus.

And have you to this embodiment has a radially outer end 12 of the main blade 2 and the radially inner end 13 of the auxiliary blades 9 are connected via a reinforcing rib 10.

  In the multiblade fan 1 according to this embodiment, when the multiblade fan unit 3 is rotated, air flows along the pressure surface 16 and the suction surface 15 of the main blade 2. When air passes through the main blade 2, the air flowing along the negative pressure surface 15 of the main blade 2 tends to be separated from the negative pressure surface 15, and a shear flow is generated behind the radial outer end 12 of the main blade 2. Tend to be formed. Here, the auxiliary blade 9 is arranged inside the air flow passing between the main blades 2. More specifically, the outlet portion between the pressure surface 16 of the radial outer end 12 of one of the main blades 2 adjacent to the radial inner end 13 of each auxiliary blade 9 and the suction surface 15 of the other main blade 2. 17. As a result, the air that has passed through the main blade 2 flows along the pressure surface 19 and the suction surface 18 of the auxiliary blade 9, so that the air flow is separated and the air flow is biased toward the pressure surface 16 side of the main blade 2. And the generation of shear flow are suppressed, and the blowing performance and noise characteristics are improved.

  Further, since the main blade 2 and the auxiliary blade 9 are connected by the reinforcing rib 10, the deformation strength of both the blades 2, 9, especially the auxiliary blade 9, is improved. Therefore, the possibility of the auxiliary blade 9 coming into contact with the radially outer end 12 of the main blade 2 due to the rotation of the fan can be eliminated, so that the original function of the auxiliary blade 9 as described above is ensured and the air blowing performance is more reliably performed. And noise characteristics can be improved.

  Further, in this embodiment, since the radial outer end 12 of the main blade 2 and the radial inner end 13 of the auxiliary blade 9 are connected by the reinforcing rib 10, both the blades 2 and 9 are connected at the shortest distance. On the other hand, it is possible to give a preferable directivity that flows to the auxiliary blade 9 without increasing the ventilation resistance to the air that has passed through the main blade 2.

  Further, since the radially inner end 13 of the auxiliary blade 9 is disposed on the inner side in the fan radial direction with respect to the radially outer end 12 of the main blade 2, the main blade 2 is separated by air separation after passing through the main blade 2. The deviation of the air flow toward the positive pressure surface 16 can be suppressed early and surely on the upstream side.

  The present invention can be suitably used for a centrifugal multiblade fan, particularly a multiblade fan used as a blower in an automotive air conditioner.

It is a front view of the multiblade fan concerning one embodiment of the present invention. It is a half section display side view of the multiblade fan of FIG. It is a sectional view taken along the line III-III in the blade unit of Figure 2. It is a sectional view taken along the line IV-IV in the blade unit of Figure 2. It is a schematic diagram which shows the air flow in the blade part of the multiblade fan based on the previous proposal of the present applicant.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multiblade ventilation fan 2 Main blade 3 Multiblade fan part 4 Rotating shaft 5 Drive plate 6 Boss part 7 Connection ring 9 Auxiliary blade 10 Reinforcement rib 11 Radial inner end of main blade 12 Radial outer end of main blade 13 Auxiliary blade 14 Radial inner end 14 Auxiliary blade radial outer end 15 Main blade negative pressure surface 16 Main blade positive pressure surface 17 Air passage 18 Auxiliary blade negative pressure surface 19 Auxiliary blade positive pressure surface

Claims (4)

A multi-blade fan section having a plurality of blades arranged in the circumferential direction around the rotation axis is provided, and air is sucked from the inner diameter end side between the blades by rotation of the multi-blade fan section, and the air is discharged from the outer diameter end section side. In the multiblade fan that discharges, a plurality of main blades are arranged radially inside, and auxiliary blades are arranged inside the air flow between the main blades radially outside, the main blades and auxiliary blades, A multi-blade fan characterized in that a reinforcing rib is provided to connect the outer edge of the main blade and the inner end of the auxiliary blade in the radial direction .   The multiblade fan according to claim 1, wherein the reinforcing rib is provided at a substantially central portion in a longitudinal direction of the main blade and the auxiliary blade. The multiblade fan according to claim 1 or 2 , wherein the main blade and the auxiliary blade are integrally formed. The multiblade fan according to any one of claims 1 to 3, wherein a radially inner end of the auxiliary blade is disposed radially inside than a radially outer end of the main blade.

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