JPS60156997A - Centrifugal type blower fan - Google Patents

Abstract

PURPOSE:To prevent exfoliation of an air current and reduce a noise and further improve efficiency of ventilation and strength of a blade by shaping a wing of each blade in such a manner as its thickness near the lifting line is large in the basal part to a disc and is gradually reduced as it parts from the disc. CONSTITUTION:The shape of a wing of a blade 2 is, as illustrated, such that its thickness near the lifting lines 21A-23A is large in the basal part to a disc 3, that is, on the swelling side face 31 of the disc 3, and is gradually reduced as it parts from said disc. This prevents exfoliation of an air current from the blade 2 and pressure change of the air current does not occur, and a noise can be prevented. Further, since the tip part of the blade 2 is shaped like a thin plate, the loss of the air current is small and the efficiency of ventilation is largely improved. Furthermore, since the tip part is shaped like a thin plate, the mass of the tip part is reduced. On the other hand, since the thickness of the basal part is shaped large, combined dimensions with the disc 3 can be largely taken and the strength of the blade 2 is augmented.

Description

[Detailed description of the invention] [Field] The present invention relates to noise reduction in a fan for a centrifugal blower.

[Prior art] A centrifugal blower has an air inlet 6 at the top as shown in Fig. 3.
1, a cylindrical casing 6 having an air outlet 62 on its outer periphery, a centrifugal blower fan 1 disposed within the casing 6 in correspondence with the air inlet 61, and a centrifugal blower fan. The centrifugal blower fan 1 consists of a disk-shaped disk 3 whose central portion bulges to one side, and one end of which is fixed to the bulging side of the disk 3. It is composed of a large number of blades 2 which are arranged in a cylindrical shape at equal intervals from the outer circumference to form a row of blades, and from a manufacturing standpoint, the large size of each blade 2 is from the leading edge 24A to the trailing edge as shown in FIG. It has the same wall thickness towards 25A. However, as shown in FIG. 3, the airflow that crosses the blade 2A has a large axial component near the air inlet 61 of the blade 2 and becomes three-dimensional, and the airflow near the disk 3 has a large radial component and becomes two-dimensional. As shown in FIG. 1, a separation area a exists on the blade vent surface 27 near the root of the blade 2 to the disk 3 where the flow velocity in the chord direction (radial direction) is high, and this separation area a suppresses pressure fluctuations in the airflow. It is the main cause of noise. For this reason, as shown in Figure 2, the patent application
No. 30700 proposes a fan for a centrifugal blower in which blades 2B are built up. However, since the air flow passes through the blade 2B three-dimensionally, the air inflow "" 61
However, the passage area was reduced, the loss of air flow was large, and the blowing efficiency of the centrifugal blower was poor.

[Object of the Invention] An object of the present invention is to provide a fan for a centrifugal blower that can reduce noise and has a good air blowing effect.

[Structure of the Invention] The fan for a centrifugal blower of the present invention includes a disk-shaped disk whose center portion bulges out to one side, and one end of which is fixed to the bulging side surface of the disk, and cylinders arranged at equal intervals around the outer periphery of the disk. In a centrifugal blower fan consisting of a large number of blades arranged in a plane, each of the blades is large, and the wall thickness near the lifting edge is large at the root of the disk and gradually decreases as the distance from the disk increases. composition.

[Effects of the Invention] With the above configuration, the centrifugal blower fan of the present invention has the following effects.

b) Since separation of airflow from the blades can be prevented, pressure fluctuations in the airflow do not occur, and noise can be reduced.

Mouth) Since the tip of the blade is shaped like a thin plate, there is little loss of air flow and the blowing effect is very good.

c) Since the tip of the blade is shaped like a thin plate, the mass of the tip is reduced, and the thickness of the root is increased, which increases the bonding area with the disk, increasing the strength of the blade. Improves durability.

[Example] The centrifugal blower fan of the present invention will be described based on an example shown in FIGS. 3 to 7.

The centrifugal blower fan 1 according to the present invention has blades 2
, a circular disc 3, the blade 2 and the disc 3
It consists of a sirocco fan 4 in which a large number of scirocco fans are disposed in a centrifugal direction, and a drive motor 5 that drives the sirocco fan 4 by a drive shaft 51.
2 is fitted inside the casing 6.

As shown in FIG. 4, the blades 2 have one end 2a fixed to the bulging side surface 31 of the disk 3, and are arranged in multiple rows in a cylindrical shape from the outer periphery 3a of the disk 3, and have a ring 212 on the outer periphery 211 of the other end. It is made up of a tip part (left end in the figure) 21, a center part 22, and a base part (right end in the figure) 23, which are formed into a single piece, with a front edge 24 that is the air inflow side, and an air outflow side. It forms a trailing edge 25 which is the side.

As shown in FIG. 5, the tip portion 21 has a front edge 24a formed with an arcuate surface 213, a rear edge 25a with an arcuate surface 214 centered around the drive shaft 51, and a front edge 24a and a rear edge 25a. Average arrow height curve 26a (radius r1
: approx. 8.8 cm), wing ventral surface (left side in the figure) 27a (radius r2 : approx. 11.1 cm), and wing back surface (right side in the figure)
28a (radius r3: approx. 8.1 cm) is a thin plate shape (wall thickness near lift line 21A: approx. 1.0 cm)
exhibits.

As shown in FIG.
An arcuate surface 223 having a radius larger than the leading edge 24a of
Similarly to the trailing edge 25a of the tip part 21, the trailing edge 25b forms an arcuate surface 224 with the drive shaft 51 as the axis, and from the average height curve 26a of the tip part 21, the wing ventral surface near the lift line 22A. Filling in direction 27b (thickness h: approx. 2cm)
The convex surface 213b is formed by performing this step.

As shown in FIG.
An arcuate surface 233 having a radius larger than the front edge 24b of No. 2
Similarly to the trailing edge 25a of the tip 21, the trailing edge 25c forms an arcuate surface 234 with the drive shaft 51 as the axis, and the average arrow height curve 2[1a of the tip 21 near the lift line 23A] Wing ventral surface 2? Filling in direction c (thickness h: approx. 8cm)
) to form the convex surface 29c.

In this way, the large blade 2 has lift lines 21A, 22A,
The wall thickness near 23A is large at the bulging side surface 31 of the disk 3, and gradually decreases as it moves away from the disk 3.

The disk 3 has a disk shape as shown in FIG. 4, and has a protruding side surface 31 to which the blade 2 is fixed, an axial center portion 32 fixed to the driving member 51, and a bulging surface 31 and the shaft. The shaft center portion 32 is a cylinder fixed to the tip end 51a of the drive shaft 51 as shown in FIG. 3, and the drive shaft 51 is inserted through the hollow portion 321. ing.

Air passes through the air inlet 61 of the casing 6 and is sucked in from the leading edge 24 side of the blades 2 of the sirocco fan 4, and is sucked into the blade vent surface 27 (27a, 27b, 2?) of each blade 2.
c), the airflow following the shape of the blade back surface 28 (28a) (1) is blown out in a centrifugal direction around the drive shaft 51, and is discharged from the air outlet 62 of the casing 6.

A) In this embodiment, the tip portion 21 and center portion 22 of the plate 2
, the thickness h of the overlay on the average arrow height curve 26a of the root portion 23 was set to approximately 0.5 cm, approximately 2 cm, and approximately 8 cm, respectively, and the ratio of the chord length X to the wall thickness H on the lift line at each part If it is as shown in Table 1, it has the same effect as this embodiment.

B) The centrifugal blower fan of the present invention is used in automobiles, air conditioners in cars, exhaust fans in factories, and the like.

[Brief explanation of drawings]

Figures 1 and 2 are simulation diagrams of a conventional centrifugal blower fan, Figure 3 is a schematic diagram of the centrifugal blower fan of the present invention, and Figure 4 is a front view of the blades of the centrifugal blower fan of the present invention. Figures 5.6.7 are side sectional views of the blades of the centrifugal blower fan of the present invention. In the diagram: 1...Centrifugal blower fan 2...Blade 3...Disc 4...Sirocco fan 5...Drive motor 6...Casing allowance
Rito Ishiguro Ken 2

Claims (1)

[Claims] A disc-shaped disk with a central portion bulging out on one side. In a centrifugal blower fan comprising a number of blades having one end fixed to the bulge of the disk and arranged in a cylindrical shape at equal intervals around the outer periphery of the disk, the large size of each blade has a lift line. A fan for a centrifugal blower characterized in that the wall thickness near the disk is large at the root of 4=J and gradually decreases as it moves away from the disk.