Patent Application
20220389932
The present invention relates to the field of heat dissipation fans, and more particularly to a magnetic-attraction fashion heat dissipation fan.
In the contemporary technology, for a heat dissipation fan to achieve the purpose of reducing vibration of fan blades in an axial direction during rotation in order to keep the fan blades rotating in a balance and stable manner, it is a common practice to include a magnetic element that pulls the fan blades downward through attracting. Magnetic suspension fans that are currently available in the market adopt a structure in which an iron plate is placed on a printed circuit board (PCB), which is retained in position by being fixed on a wire frame of a motor. Such an arrangement has various drawbacks:
(1) The iron plate has to be tightly positioned on the PCB and this would occupy a large amount of space available on the PCB, making it necessary for electronic components to avoid it by being re-arranged as components surface-mounted on two sides. This leads to an increase of the SMT (Surface-Mounting Technology) cost.
(2) The iron plate must be pre-formed with holes for positioning on the wire frame and a sensing hole for a Hall IC of the fan. This makes the entire iron plate no longer a complete circle, and the magnetic attraction forces that they apply to the fan blades would be of different strengths.
(3) Positioning the iron plate during assembling is complicated and tedious and is expensive. Further, such an arrangement of the iron plate being exposed to the outside makes it easy to oxidize, leading to reduced reliability.
In order to alleviate and overcome the above-discussed drawbacks and insufficiency of the magnetic-attraction fan, the present invention provides a novel improvement in respect of the structure by designing a heat dissipation fan having a magnetic suspension structure.
To achieve the above objective, the present invention provides the following technical solution:
A heat dissipation fan of a magnetic suspension structure is provided, wherein the fan comprises:
a fan frame, the fan frame being a plastic object, the fan frame comprising a base portion and a circumferential wall portion enclosing the base portion, the base portion having a central portion that is raised upward to form a central shaft, the central shaft being formed with a shaft bore;
a motor coil, the motor coil being mounted on an outer circumference of the central shaft and is conductively connected to a printed circuit board (PCB);
a fan blade assembly, the fan blade assembly comprising a hub portion and blades extending outward from the hub portion in a radial direction, the hub portion being provided with an axle core and a rubber magnet, the fan blade assembly being mounted, in a rotatable manner, in the fan frame in such a way that the axle core is in alignment with and mounted into the shaft bore of the central shaft, the rubber magnet being arranged to surround and enclose a circumference of the motor coil; and
an iron plate, the iron plate being fixed to the base portion of the fan frame through injection molding such that an orthographic projection of the rubber magnet is cast on the iron plate,
wherein interaction among the rubber magnet, the motor coil, and the iron plate creates an operation environment of magnetic suspension and magnetic attraction, and the fan blade assembly is operated for rotating in such an operation environment.
The above technical solution is further such that the iron plate is fully enclosed and embedded in the base portion of the fan frame.
The above technical solution is further such that the iron plate is partially enclosed and fixed in the base portion of the fan frame and is partially exposed at an inside surface or an outside surface of the base portion.
The above technical solution is further such that a magnet is provided on the base portion of the fan frame, and the magnet and the iron plate are staggered with respect to each other, and the magnet is coaxial with the axle core of the fan blade assembly, the magnet magnetically attracting the axle core of the fan blade assembly.
The above technical solution is further such that the iron plate is in the form of a circular ring, and the magnet is located in an inscribed circular area of the iron plate, the magnet having an outside diameter that is greater than a diameter of the axle core.
The above technical solution is further such that the axle core of the fan blade assembly is mounted into the shaft bore that is formed in advance in the central shaft by means of a hydraulic self-oiling bearing.
The above technical solution is further such that a wear-resistant pad is provided on an inner bottom of the shaft bore, and the wear-resistant pad support an inserted end of the axle core to abut thereto.
The above technical solution is further such that the rubber magnet is made by homogeneously adding magnetic powder in a rubber material and is forced into an iron casing using a fixture to form a closed circular ring rubber piece, which is further subject to high voltage magnetization to have the magnetic powder aggregating in the rubber material to form the north and south poles, this providing a fixed annular magnetic field; and the motor coil is made, through varying different wiring impedance, to form a varying magnetic field that is changeable, wherein the fixed annular magnetic field covers the varying magnetic field, generating magnetic suspension effect through mutual attraction and mutual expulsion.
The present invention adopts an arrangement of using a rubber magnet in combination with an iron plate to realize an effect of magnetic attraction, and further, the iron plate is directly fixed, through molding, to the base portion during the molding operation of the base portion of the fan frame so as to not only simplify the assembling of the iron plate, making the fabrication easy and reducing fabrication cost, but also ensure integrity and reliability of components, such as a PCB, ensuring the operability and the service life of the heat dissipation fan. Further, fixing the iron plate through the injection molding operation allows easy setting of the distance and strength of magnetic attraction as desired for the purposes of adjusting the effect of magnetic attraction, and also, through setting of the assembling sizes of a motor coil and the rubber magnet, an upward magnetic levitation or suspension force may be generated and applied to the motor coil during the operation of the fan blade assembly, wherein when the two forces of magnetic suspension and magnetic attraction reach a balance point, the fan blade assembly is held in a suspended magnetic field and such a magnetic field structure greatly reduces the friction between the axle core and bearing, thereby reducing noise of the fan and extending the service life of the fan.
Referring to
Referring to
Referring to
Referring to
The present invention adopts an arrangement of using a rubber magnet in combination with an iron plate to realize an effect of magnetic attraction, and further, the iron plate is directly fixed, through molding, to the base portion during the molding operation of the base portion of the fan frame so as to not only simplify the assembling of the iron plate, making the fabrication easy and reducing fabrication cost, but also ensure integrity and reliability of components, such as a PCB, ensuring the operability and the service life of the heat dissipation fan. Further, fixing the iron plate through the injection molding operation allows easy setting of the distance and strength of magnetic attraction as desired for the purposes of adjusting the effect of magnetic attraction, and also, through setting of the assembling sizes of a motor coil and the rubber magnet, an upward magnetic levitation or suspension force may be generated and applied to the motor coil during the operation of the fan blade assembly, wherein when the two forces of magnetic suspension and magnetic attraction reach a balance point, the fan blade assembly is held in a suspended magnetic field and such a magnetic field structure greatly reduces the friction between the axle core and bearing, thereby reducing noise of the fan and extending the service life of the fan.
