JPH05272493A - Impeller structure of centrifugal fan - Google Patents

Abstract

PURPOSE:To attain high efficiency adapted to an operating condition, low noise, light weight and the improvement of rotational strength by designing a vane which is ideal fluid equipment and a wheel which is an ideal high speed rotor separately, and connecting these two to obtain an ideal impeller. CONSTITUTION:An airfoil fitting part 3 and a disk 4 made of aluminum iron, and a high speed rotor wheel formed of a shroud 5 are designed and manufactured first. The airfoil fitting part 3 is provided with a caulking tab 8, and the disk 4 and shroud 5 are provided with an elongated hole 9 into which the tab 8 is inserted for caulking. An airfoil part 2 is molded out of heat resistant plastic material and provided coveringly at the airfoil fitting part 3 to form an airfoil vane. The tab 8 of the airfoil vane 1 is inserted into the elongated hole 9 of the disk 4 and shroud 5 and caulked to complete an impeller. The thus formed impeller can cope with any service condition, and high efficiency, low noise, light weight, high rigidity and high balance can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an airfoil impeller used for centrifugal blowers and mixed flow blowers.

[0002]

2. Description of the Related Art It is well known that, as an impeller used for a centrifugal blower or a mixed flow blower, an impeller having a vane-shaped cross section has high efficiency and low noise.

The airfoil blade is classified into the following three types depending on the material and the manufacturing method. A-type airfoil blade: Iron or aluminum plate bent and molded by a press. B type airfoil blade: An extruded (or drawn) aluminum material. C type airfoil: Injection or hand lay-up molding of plastic material. The constituent elements (blades, disks, shrouds) of the impeller are formed of the same material (iron material, aluminum material, plastic material) and fixed by caulking, welding, bonding, or other construction method. After that, the impeller using each type of airfoil was used as an A type impeller, a B type impeller,
It is called C type impeller.

When selecting a fan with high efficiency and low noise,
First, the C type impeller is selected. The reason for this is that since an accurate blade shape can be obtained, the ventilation efficiency is high, and because of the physical properties peculiar to the material (low natural frequency), there is no resonance and there is low noise. However, since the plastic material is weak against heat, when it is operated in a high temperature environment or when a high temperature gas is blown, it is deformed (creep) due to heat, which destroys the dynamic balance and eventually leads to destruction. Further, when the airfoil blade is formed by injection molding, sink marks are likely to occur on the surface of the airfoil, which makes it difficult to obtain an accurate airfoil and causes turbulence. The B type impeller is selected as the second, but this type has high air blowing efficiency because it can obtain blades with an accurate airfoil shape, but the natural frequency of the material is high, so noise is several percent higher than that of plastic. . The weight is also heavy. The third type is the A type (iron or aluminum) impeller. With this type, it is difficult to form the blade shape accurately, so the ventilation efficiency is low and the turbulent noise is high. Since the natural frequency is high in terms of physical properties, low noise cannot be expected. However, it has the advantage that it is the lightest and has high strength as a rotating body.

[0005]

In recent years, there has been a demand for higher efficiency and lower noise at every place where the blower is used. At the same time, further downsizing is required, and the blower is forced to operate at high speed, and the impeller is also required to have high rigidity and high dynamic balance to withstand high speed operation. This means that the rigidity of the A-type impeller, the blowing efficiency of the B-type impeller, and the low noise of the C-type impeller are required at the same time, and the structure and manufacturing method of the conventional impeller can be completely solved. Not a level. Although there is Japanese Utility Model Laid-Open No. 64-41697 that solves this problem, it cannot be said that the problem has been solved.

[0006]

[Means for Solving the Subject] Originally, an impeller of a blower is required to have two different functions at the same time. One is the function as a fluid device (aeration efficiency, aerodynamic characteristics and noise characteristics called low noise), and the other is a function as a high-speed rotating body (mechanical characteristics such as rigidity and dynamic balance). In the conventional impeller design, since these were pursued at the same time, only half-finished results were obtained. In pursuit of two functions, the present invention separates and designs an "ideal fluid device blade" and an "ideal high-speed rotating vehicle", and then combines the two. , An impeller structure based on a new design concept of obtaining an “ideal impeller”. In the design procedure according to the present invention, first, the A-type impeller, which is the best among the three types as a rotating body, is selected as the basic structure of the "car", and the most suitable metal is selected for use conditions. Next, the [wing shape], which is a component of the "wing" as a fluid device, and the "wing shape", which has been conventionally pursuing two functions "blade" and "car" at the same time, It is divided into two parts, the "wing shape attachment part", which is a component of the "car". Then, in the [wing shape attachment part], a bead, which was strictly prohibited in "a blade as a fluid device", is inserted to increase the rigidity, and the plate thickness is reduced by that amount to make it lighter.
This [wing-shaped attachment part] is fixed to a disk or shroud made of the same metal material to obtain an "ideal high-speed rotating car". Then, the blade shape part is attached to this car to make an impeller. In this way, the [wing shape attachment part] bears the function of the "car", so the [wing shape part] is the "blade".
It is only necessary to pursue the function of, and select the optimum material (for example, plastics, ceramics, etc.) for the usage conditions of the impeller.
It has become possible to design and manufacture with the optimum shape. As a result, according to the designing method of the present invention, it is possible to provide an impeller that can be used under all conditions of use and that has high efficiency, low noise, light weight, high rigidity, and high dynamic balance.

[0007]

Example 1 Preferred of the present application

[Embodiment 1] The impeller (FIG. 4) of the blower used in the indoor unit of the ceiling embedded air conditioner of FIG. 5 will be described. In FIG. 4, the indoor unit is an annular heat exchanger (1
2) is arranged, and further, an auxiliary heater (13) for heating, an impeller (10) for a single suction type centrifugal blower, a motor (14) for driving the impeller, and the like are arranged inside thereof. Indoor air is fed from the suction grille (15) to the bellmouth (1
It is sucked into the impeller (10) through 6), exchanges heat through the auxiliary heater (13) and the heat exchanger (12), and is blown out into the room through the blowout port (17). Fourth
As shown in the figure, the blower impeller 10 includes a disc 4
A large number of airfoil blades 1 are arranged and fixed between the shroud 5 and the shroud 5. The conditions required for the impeller (10) are extremely low noise because the distance between the fan, which is a noise source, and the indoor occupants is short, and an auxiliary heater for heating is arranged near the fan impeller. Therefore, with heat-resistant creep characteristics,
Because it is a ceiling-embedded unit, it is lightweight, etc. The C type impeller is most suitable for the conditions, but it cannot be used because of the conditions. A type impeller and B type impeller are recommended for the conditions. Type A is the most suitable for the condition, but it does not adapt to the condition. Since not all types of impellers can meet all the conditions, the B type impeller was adopted as the second best, but since it was attached to a ceiling-embedded air conditioner, weight reduction was desired. Next, a designing / manufacturing method according to the present invention will be described with reference to FIG. First, a "high-speed rotating body," which is formed from an aluminum plate-shaped blade-shaped mounting portion 3, a disk 4, and a shroud 5,
Design and manufacture "cars". In order to reduce the weight, beads are added to the components 3, 4, and 5 to increase the rigidity.
The plate thickness may be reduced to reduce the weight. The blade-shaped mounting portion 3 is provided with a tab 8 for caulking, and the disk 4 and the shroud 5 are provided with an elongated hole 9 into which the tab is inserted and caulked. The blade-shaped portion 2 is formed by using a heat-resistant plastic material and is covered with the blade-shaped mounting portion 3 to form the blade-shaped blade 1. next,
The tabs 8 of the airfoil blade are inserted into the slots 9 of the disc 4 and the shroud 5 and caulked to complete the impeller 10. Here, the covering method of the blade shape portion 2 on the blade shape attaching portion 3 may be so-called outsert molding by an injection molding machine,
Hand layup is also acceptable. There is also a method in which the airfoil mounting portion 3 is inserted into and bonded to the airfoil shaped portion 2 manufactured by cutting a plastic extrusion molding material. For the airfoil shape section 2, the optimum plastic material and the optimum production method may be selected depending on the operating conditions, the number of productions, and the allowable cost. The caulking may be replaced by a thermal caulking or a welding method. Since the aerodynamic characteristics and noise characteristics of the blower are mostly determined by the airfoil blades, the above structure alone can satisfy the requirements,
For further improvement, it is also effective to cover the inside of the disc 4 and the shroud 5 (on the air passage side) with a plastic material. To meet the demand for even lower noise, see Fig. 2.
As shown in FIG. 1, by cutting the outer peripheral side of the airfoil-shaped portion into a jagged shape, it is also effective to cancel the phase of the noise generated when the gas leaves the outer edge portion of the blade to cancel the noise. Further, for further weight reduction, as shown in FIG. 6, the inside of the blade-shaped portion is molded with foamable plastic,
It is also effective to cover the outside with heat-resistant plastic. In the present Example 1, as compared with the conventional B type impeller, the air volume and the air pressure are the same, the noise is reduced by 2 decibels or more,
18% or more reduction in weight 7% increase in breakage rotation speed 30% or more in cost reduction.

[0008]

[Embodiment 2] When used for an exhaust air blower of a chemical factory, stainless steel or corrosion-resistant aluminum may be adopted as a material for the blade-shaped mounting portion 3, the disk 4 and the shroud 5. 15% or more weight reduction compared to conventional C type impeller 3
There was an effect such as a cost reduction of 0% or more and an increase of the breaking rotation speed of 15% or more.

[0009]

[Embodiment 3] When blowing a high-temperature gas, it is effective to use heat-resistant stainless steel for the material of the blade-shaped mounting portion 3, the disk 4, and the shroud 5 and ceramic for the blade-shaped portion. Compared with the conventional C type impeller made of steel plate, it is expected to have a great effect on weight reduction and cost reduction.

[0010]

[Embodiment 4] When a hard powdery object is mixed in the blown gas and wear of the blade-shaped portion is feared, an abrasion-resistant ceramic is used for the blade-shaped portion. Steel plates or stainless steel plates are used for the airfoil mounting part, disks and shroud, and ceramic is sprayed if necessary.

[0011]

As described above, according to the present invention, the blower impeller is made of a material in order to separate and pursue the two functions of the "wheel as a high-speed rotating body" and the "blade as a fluid device". Since there is a great degree of freedom in selecting the shape and designing the shape, it is possible to supply a blade-type impeller with high efficiency, low noise, light weight, and high rotational strength adapted to operating conditions at low cost.

[Brief description of drawings]

1 is a cross-sectional view of an airfoil blade according to the present invention.

FIG. 2 is a plan view of an airfoil blade according to the present invention.

FIG. 3 is a disk, airfoil blade, of an impeller according to the invention,
Sectional drawing of a shroud.

FIG. 4 is a plan view of an impeller of a centrifugal blower according to the present invention.

FIG. 5 is a cross-sectional view of an indoor unit of a ceiling-embedded air conditioner.

[Explanation of symbols]

 1 Wing blade 2 Wing shape part 3 Wing shape mounting part 4 Disk 5 Shroud 8 Tab 9 Slot hole 10 Wing blade impeller 11 Main body case 12 Heat exchanger 13 Auxiliary heater 14 Motor 15 Suction grill 16 Bell mouth 17 Blowout port

Claims (6)

[Claims] 1. A disk 4, an airfoil blade 1, and a shroud 5.
In a centrifugal blower impeller whose main component is, the airfoil blade 1 is composed of a blade-shaped portion 2 and a blade-shaped mounting portion 3, the blade-shaped mounting portion 3 is fixed to a disk 4 and a shroud 5, and the blade-shaped portion 2 is The structure of the impeller which is covered and fixed to the blade-shaped mounting portion 3. 2. The impeller according to claim 1, wherein the disk 4, the shroud 5, and the blade-shaped attachment portion 3 are made of a metal plate, and the blade-shaped portion 2 is made of a plastic material. 3. The structure of the impeller according to claim 2, wherein the inside of the blade-shaped portion 2 is formed of a foamable plastic material and the outside of the blade-shaped portion 2 is formed of a non-foaming plastic material. 4. The vibration damping steel plate, the vibration damping stainless steel plate, or the vibration damping aluminum plate as a material for all or a part of the disk 4, the shroud 5, and the blade shape mounting portion 3 as set forth in claim 2 or claim 3. Impeller structure. 5. The structure of the impeller according to claim 2, wherein the disk 4, the shroud 5, and the blade-shaped mounting portion 3 are all or partly made of a fiber-reinforced plastic material. 6. The impeller structure according to claim 2, wherein the blade-shaped portion 2 is made of a ceramic material.