JPH05280494A - Propeller fan - Google Patents

Abstract

PURPOSE:To prevent the generation of strain, deformation and warp, reduce weight and the material cost, and shorten the cycle time (in particular cooling time) in molding. CONSTITUTION:As for a propeller fan 3 having a plurality of blades 2 around a boss part 1 in turned-down form, the base edge part 4 of each blade 2 is made thicker than other places and made hollow, and a rib 7 is formed on the inner surface of the boss part 1. The base edge part of the rib 7 is made thicker than other parts and made hollow, and a hollow part 9 formed at the base edge part of the rib 7 and a hollow part 10 formed at the base edge part of the blade 2 are put into communication state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propeller fan for a ventilation fan or the like.

[0002]

2. Description of the Related Art Conventionally, a propeller fan for a ventilating fan of this type has a shape in which blades directly project from a boss, and has the following problems. a. The base end portion of the blade becomes substantially thick, and the amount of heat shrinkage during cooling and solidification concentrates on the thick portion, which causes sink marks, distortion, warpage, and the like. b. Above a. In order to eliminate the above problem, it is necessary to reduce the thickness of the base end portion of the blade, and the following problems occur. As the propeller fan rotates, it receives wind pressure (lift force) on the blades, so it is necessary to thicken the base end portions of the blades in order to have corresponding rigidity. The protuberance-shaped boss portion needs to be thick in order to add rigidity to the portion of the protuberance-shaped boss portion that is in contact with the base end portion of the blade. For this reason, it takes a long time to cool, the molding cycle time becomes long, and the productivity deteriorates.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel propeller fan which is devised to solve the above problems and devised to efficiently solve the problems.

[0004]

In order to achieve the above object, a propeller fan according to the present invention comprises a propeller fan 3 integrally provided with a plurality of blades 2 around a protuberant boss portion 1. The base end portion 4 of the blade 2 is made thicker and hollow than the other portions, and the rib 7 is provided on the inner surface of the boss portion 1. The base end portion 8 of the rib 7 is made thicker and hollow than the other portions. The hollow portion 9 provided at the base end portion 8 of the rib 7 and the hollow portion 10 provided at the base end portion 4 of the blade 2 are in communication with each other.

[0005]

Example In the example shown in the figure, after injecting an insufficient amount of molten synthetic resin to fill the mold cavity into the mold cavity, subsequently injecting a gas such as nitrogen from the same inlet under pressure, After the gas injection, the molten resin is further injected to obtain a mold cavity, which is obtained by a molding method. A plurality of blades 2 are integrally provided around a boss portion 1 of the bowl shape, and each blade 2 The base end portion 4 of is made thicker and hollow than the other portions, and the rib 7 is provided on the inner surface of the boss portion 1. The base end portion 8 of the rib 7 is made thicker and hollow than the other portions. The hollow portion 9 provided at the base end portion 8 of the rib 7 and the hollow portion 10 provided at the base end portion 4 of the blade are in communication with each other. still,
Gas such as nitrogen is pressurized and injected from the outer surface portion of the upper end portion of the rib 7, and selectively enters the thick wall portion (base end portion) of the blade 2 via the thick wall portion (base end portion) of the rib 7. Both of the hollow portions 9 and 10 are continuously formed at once.

1 and 2 are shown in a schematic view without draft. Reference numeral 11 in the drawing is a shaft mounting member, which is provided by an insert.

[0007]

In the present invention, the base end portion 4 of the vane 2 and the base end portion 8 of the rib 7 which are externally thickened are thinned due to the presence of the hollow portions 10 and 9 and are thus lightened. In addition, the material cost is reduced and the molding cycle time (especially cooling time) is shortened. In particular, the hollow portion 9 of the base end portion 8 of the rib 7 serves to guide a gas such as nitrogen when forming the hollow portion 10 in the base end portion 4 of the blade 2.

[0008]

In the propeller fan according to the present invention, the base end portion 4 of each blade 2 and the base end portion 8 of the rib 7 are hollow portions 10,
The presence of 9 can prevent sink marks, distortion, and warpage, reduce the weight, reduce the material cost, shorten the molding cycle time (particularly the cooling time), and reduce the hollow portion 1
By providing 0 and 9, not only the base end portion 4 of the blade 2 becomes thick and the strength of this portion 4 increases, but also the draft angle can be increased by increasing the thickness, so that the resin flow It has excellent effects such as improved productivity, easier mold release, improved work efficiency, and improved productivity.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the present invention.

FIG. 2 is a partially cutaway bottom view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boss part 2 Blade 3 Propeller fan 4 Base end part 7 Rib 7 8 Base end part 9 Hollow part 10 Hollow part 11 Shaft mounting member

Claims (1)

[Claims] 1. A propeller fan (3) integrally provided with a plurality of blades (2) around a protuberance-shaped boss (1), wherein a base end portion (4) of each blade (2) is made thicker and hollow than other portions. At the same time, a rib 7 is provided on the inner surface of the boss portion 1, and the base end portion 8 of the rib 7 is made thicker and hollow than the other portions.
A propeller fan characterized in that a hollow portion 9 provided at a base end portion 8 of the blade and a hollow portion 10 provided at a base end portion 4 of the blade 2 are in a communication state.