Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With product ejector
Reexamination Certificate
2000-04-17
2001-08-21
Heitbrink, Tim (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With product ejector
C425S441000, C425SDIG005
Reexamination Certificate
active
06276923
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an axial fan, a method of manufacturing an impeller for the axial fan, and a mold for manufacturing the impeller of the axial fan and, more particularly, to a technology concerning an axial fan having an impeller that can obtain a sufficiently large air flow and wind pressure regardless of its compact, flat shape.
In an axial fan, an impeller, which is formed by arranging a plurality of vanes on the outer circumferential surface of a rotor having a permanent magnet on its inner circumference, is supported to be rotatable about the main body side stator of the axial fan. When a rotating magnetic field is generated in the stator, a desired air flow and wind pressure are obtained upon rotation of the rotor. Since the axial fan can be made compact and flat, it is incorporated mainly in an electronic equipment which is formed compact and flat, to prevent an increase in temperature caused by heat generated by an internal electronic circuit board and the like.
Further downsizing and flattening of the axial fan are demanded in order to cope with recent size reduction of electronic equipments. The reduction in air flow and wind pressure upon such downsizing and flattening is not allowable. Therefore, various proposals have been made concerning an axial fan in order to ensure a large air flow and wind pressure.
“A Compact Blower” disclosed in Japanese Patent Publication No. 4-502052 is a proposal for performing downsizing and flattening while ensuring an air flow and wind pressure. According to this proposal, the vanes of an axial fan having an impeller are integrally molded so as to extend towards the central portion of the base portion of the impeller. When the axial fan is formed in this manner, a decrease in air flow caused by a decrease in outer diameter of the impeller and in area of the vanes as the result of downsizing can be prevented.
SUMMARY OF THE INVENTION
According to this proposal, the plurality of vanes formed on the outer circumferential surface of the impeller of the axial fan are continuously molded to form under portions or back side portions extending to the central portion of the base portion of the impeller. Therefore, the slide piece of the mold that forms the “under-molding portions” for the vanes must be pulled out from the central portion of the base portion of the impeller in parallel to the radial direction. As a result, the mold cannot but become complicated. Accordingly, the mold becomes very expensive.
A so-called multi-cavity mold becomes very complicated and is difficult to realize.
When the slide piece that forms the under-molding portion side for the vanes is to be pulled out from the mold in the radial (lateral) direction, the slide piece cannot be pulled out by twisting. Therefore, it is impossible to form vanes at an angle in accordance with the rotating peripheral velocity of the vanes, and the vanes cannot be formed into a form which is ideal for obtaining a desired air flow and wind pressure.
In the above proposal, a curved surface is formed on the outer circumferential surface of the base portion that forms the under-molding portions for the vanes of the impeller, so that air supplied by the under-molding portions of the vanes during rotation is supplied to the vanes on the outer circumferential side. The area of the vanes forming the under-molding portions sharply decreases at a portion closer to the central portion of the base portion. Therefore, the flow of air cannot be reliably captured by the vanes at the under-molding portions.
Since a curved surface is formed on the outer circumferential surface of the base portion of the impeller, the rotor magnet to be incorporated is limited-to compact, flat one that does not interfere with the curved surface, and the structure of the stator is accordingly largely limited.
The present invention has been made in view of the problems described above, and has as its object to provide a compact, flat axial fan which is not limited by the shape of an incorporated rotor magnet and ensures a sufficiently large air flow and wind pressure, wherein the slide (under) piece of a mold that forms the under-molding portions of the vanes of the impeller of the axial fan is pulled out while being twisted (while performing a helical motion) in the direction of the central axis of the base portion of the impeller, so that the mold can be formed simple to realize a multi-cavity mold, and the vanes can be formed into an ideal form by setting vane angles depending on different rotating peripheral velocities of the vanes, so that air can be supplied from the under-molding portions of the vanes to the vanes on the outer circumferential side during rotation of the impeller, a method of manufacturing an impeller for the axial fan, and a mold for manufacturing the impeller of the axial fan.
In order to solve the above problems and to achieve the above object, according to the present invention, there is provided an axial fan comprising an impeller integrally formed, by resin molding, with a plurality of vanes extending from a bottomed cylindrical body to which a rotary axial support shaft body is formed at a center of rotation of a bottom surface, each of the vanes being constituted by a main vane extending from an outer circumferential surface of the bottomed cylindrical body at a predetermined tilt angle, and a sub-vane extending, on a substantially flat outer side surface forming the bottom surface, from the main vane toward the center of rotation continuously at the predetermined tilt angle to supply air to the main vane.
There is also provided a method of manufacturing an impeller for an axial fan having the impeller integrally formed, by resin molding, with a plurality of vanes extending from a bottomed cylindrical body to which a rotary axial support shaft body is formed at a center of rotation of a bottom surface, comprising in order to form each of the vanes integrally by resin molding with a main vane extending from an outer circumferential surface of the bottomed cylindrical body at a predetermined tilt angle, and a sub-vane extending, on a substantially flat outer side surface forming the bottom surface, from the main vane toward the center of rotation continuously at the predetermined tilt angle to form an under-molding portion, arranging an under piece for molding the under-molding portion and for introducing a molten resin, performing gate cut after the resin is set, causing the under piece to perform a helical motion at a predetermined angular pitch in synchronism with mold opening, and retracting the under piece from the under-molding portion in a direction of mold opening, thereby obtaining at least one impeller.
There is also provided a mold for manufacturing an impeller for an axial fan having the impeller integrally formed, by resin molding, with a plurality of vanes extending from a bottomed cylindrical body to which a rotary axial support shaft body is formed at a center of rotation of a bottom surface, comprising a mold base portion driven to a mold open state and a mold closed state and arranged in a resin injection molding machine, and a plurality of mold pieces that form a cavity for forming, by integral resin molding, the vanes each comprising a main vane extending from an outer circumferential surface of the bottomed cylindrical body at a predetermined tilt angle, and a sub-vane extending, on a substantially flat outer surface that forms the bottom surface, from the main vane toward the center of rotation continuously at the predetermined tilt angle to form an under-molding portion, wherein one of the plurality of mold pieces forms an under piece which has an under shape portion for molding the under-molding portion and a runner hole portion for introducing a molten resin, which performs gate cutting after the molten resin is set, and which is helically driven at a predetermined angular pitch in synchronism with mold opening of the mold base portion, and the under piece is retracted in a mold opening direction from the under-molding port
Shingai Hiroyuki
Umeda Yukihide
Burns Doane , Swecker, Mathis LLP
Heitbrink Tim
Nidec Copal Corporation
LandOfFree
Mold for manufacturing an impeller for an axial fan does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Mold for manufacturing an impeller for an axial fan, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mold for manufacturing an impeller for an axial fan will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2438325