JPS611897A - Propeller fan for air conditioner - Google Patents

Abstract

PURPOSE:To reduce the breakage of a boss, further thin a propeller fan and increase blast amount by providing cylinders having different diameter on both sides of a core plate to eliminate stress concentration in the core plate while improving axial deformation strength of the core plate to provide a high temperature resisting structure. CONSTITUTION:A resin made sturdy propeller fan for an air conditioner is obtained from cylindrical ribs 2b, 2e having different diameters and disposed on the left and right sides of a core plate 2a to reduce stress concentration. Said fan also has extremely small deformation and no reduction of blast amount even during running in high temperature of 70 deg.C. Also, by directing the cylindrical rib 2b having larger diameter to the fan motor side is thinned a product. By directing the cylindrical rib 2c having smaller diameter to the intake side or providing vertical ribs 2e on the upper portion of the cylindrical rib 2c is efficiently bucketed up axial air at the intake side to increase the blast amount.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to the structure of a resin propeller fan suitable for sending high-temperature air in combination with a heat exchanger such as a room air conditioner. In recent years, the price competition for exported room air conditioners for tropical regions has become intense, and as a result, there has been a strong demand for the development of resin propeller fans that can be made at low cost, and there is a need for structures that do not deform even at high temperatures of approximately 70°C.

[Background of the invention]

The boss portion of a conventional propeller fan has a structure in which a cylindrical portion is formed in one direction from the outer periphery of the core plate at the center of the impeller to form an arm shape, and blades are arranged around the outer periphery of the cylindrical portion.

When this machine is operated at high temperatures, the blade approaches the core plate side due to centrifugal force (force is applied), and tensile stress in the outer circumferential direction is generated at the root of the blade, causing the long cantilevered cylindrical part to creep into a polygonal shape. It has disadvantages such as deformation, which reduces the angle of inclination of the blade and greatly reduces the air volume, as well as causing surface runout and loss of dynamic balance.
0°C was the limit of use. In order to eliminate this problem, a method of forming double cylinders in the same direction can be considered, but in this case, if a part of the fan motor is inserted into the boss part and the product is made thinner, the motor will not be inserted. There was a drawback that made it possible. It is also possible to simply provide cylindrical parts with the same diameter on both sides around the core plate part, but in this case, one cylindrical part is located at the leading edge of the blade, and the other cylindrical part is located at the trailing edge of the blade. Since tensile stress is applied to each boss, the boss is deformed in a more complicated manner than in the case where one side is cylindrical, which not only worsens the dynamic balance of the fan but also reduces the angle of inclination of the blades. Further, there was a problem in that the stress caused by both cylinders was concentrated at the tip of each plate part supporting the cylinder part, resulting in damage.

[Purpose of the invention]

An object of the present invention is to provide a resin propeller fan for an air conditioner that eliminates the above-mentioned drawbacks, reduces the decrease in the angle of inclination of the blades, reduces damage to the boss, and contributes to making the product thinner. It is in.

[Summary of the invention]

That is, by providing cylinders with different diameters on both sides of the core plate, stress concentration in the core plate is eliminated, and at the same time, the deformation strength in the axial direction of each plate is improved to create a structure that can withstand high temperatures, and The structure is also advantageous when combined with a fan motor as a thin product.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

■ is the blade, 2 is the boss, 2a is the right plate of boss 2, 2b is the first cylindrical rib that stands up integrally on the fan motor side, 2c stands up integrally with a smaller outer diameter ° in the opposite direction to 2b The second cylindrical rib 2d stands up by connecting the first cylindrical rib and the right plate 2a, 28, 2f stands up the vertical rib by connecting the right plate 2a above and below the second cylindrical rib, 1a 1b is a trailing edge that contacts the first cylindrical rib 2b at the base of the blade and is located on the wind outlet side, and 1b is a front edge that contacts the second cylindrical rib 2c at the base of the blade and is located on the wind suction side.

When a resin propeller fan with the above structure is rotated, centrifugal force applies tensile force around the rear edge 1a and front edge 1b, and both cylindrical ribs 2b and 2cir try to widen, but the length of the cylindrical ribs is halved. In addition, the deformation of the first cylindrical rib 2b can be suppressed to an extremely small deformation of the second cylindrical rib 2 on the core plate 2a which is subject to secondary deformation.

Therefore, deformation of the blade inclination angle θ can be extremely reduced, and a decrease in air volume can be prevented. In addition, the occurrence of surface runout and unbalance can be prevented at the same time. Also, the vertical ribs 2d and 2e contribute to increasing strength as in the past, but in addition to increasing strength, the vertical rib 2e also serves as a blade. Since the diameter of the second cylindrical rib 2c is small, air 1 in the axial direction on the suction side can be efficiently pumped up, contributing to an increase in the amount of air blown. Based on the prototype study, the material was acrylonitrile styrene (AS resin) based on glass fiber 2.
A mixture of 0% (weight ratio) was used, and the blade outer diameter was 360nwn, the number of blades was 6, the blade tip width (maximum part) was 175nwn, and the blade inclination angle was 30° at the tip (
(with respect to the circumferential direction), blade root middle (minimum part) 80nw
n, the first cylindrical rib of the boss has an outer diameter of 120 mm and a cylindrical length of 40 + nm, a second cylindrical rib has an outer diameter of 90 mm and a cylindrical length of 25 nwn, and 4 vertical ribs 2d.

Even if an air conditioner equipped with four vertical ribs 2f is installed in a window air conditioner and operated for one year in high-temperature air at 70°C after heat exchange, the blade inclination angle θ can be extremely reduced to within 2°. As for the air volume, by reducing the diameter of the second cylindrical rib 2c, the suction of air became smooth and the deformation of the blade was sufficiently compensated for, and the same air volume could be ensured.

Furthermore, in a prototype product in which eight vertical ribs 2e were provided on the fan, the air volume could be increased by 2%. In addition, since the structure includes two first cylindrical ribs with a large diameter, the fan motor 4 can be placed inside, and the second cylindrical rib 2c is connected to the thickness of the central metal shaft 3. By providing the product inside, the product can be made as thin as before.

As explained above, according to the present invention, since the structure is such that the cylindrical ribs 2b and 2c having different left and right diameters are arranged with the right plate 2a as the border, stress concentration can be reduced. May 178 Relationship with the case of the person making the amendment Name of patent applicant Name '5101111 Type Company Hitachi Manufacturing
Subject of amendment: Title column of the invention in the description.

Claims (1)

[Scope of Claims] 1. On both sides of the core plate (2a) on the boss, first
A propeller fan for an air conditioner, characterized in that a cylindrical rib (2b) and a second cylindrical rib (2c) are integrally provided. 2. The propeller fan for an air conditioner according to claim 1, wherein the second cylindrical rib (2c) on the side located on the suction side has a small diameter. 3. For an air conditioner according to claim 1, in which the diameter of the second cylindrical rib (2c) side is made small and a vertical rib (2e) is provided between the core plate (2c) and the outer periphery of the second cylindrical rib (2c). propeller fan.