Patent Publication Number: US-10781822-B2

Title: Fan impeller with metallic blades and method for manufacturing the same

Description:
TECHNICAL FIELD 
     The present invention relates to a heat-dissipating fan and, in particular, to a fan impeller having metallic blades and a method for manufacturing the fan impeller. 
     BACKGROUND 
     Conventional heat-dissipating fans are mostly a structure in which blades and a fan hub are integrally formed. Such a structure is of simple construction and may be easily produced by a simple manufacturing process, which enables production of a small and slim type heat-dissipating fan. The minimum thickness of a blade in this structure is subject to the plastic structural strength and the skill and technique with which an injection molding process is performed. As a result, no more blades can be added in the limited space of this structure, so further improvement in the performance of the conventional heat dissipating fans cannot be obtained. 
     In view of the foregoing, the inventor made various studies to improve the above-mentioned problems, on the basis of which the present invention is accomplished. 
     SUMMARY 
     The present invention provides a fan impeller having metallic blades and a method for manufacturing the fan impeller. 
     The present invention provides a fan impeller including a fan hub, an outer circular frame, and a plurality of metallic blades independent from one another. Two ends of each of the metallic blades are a root and a distal end, respectively. At least a portion of the root is embedded in the fan hub, and at least a portion of the distal end is embedded in the outer circular frame. 
     It is preferable that the distal end includes a retention pin that outwardly extends away from a bend of the distal end so that the bend and the retention pin of the distal end, in combination, embeddingly extend in the outer circular frame along a circumference direction of the outer circular frame. There can be a through hole formed on the distal end, and at least a portion of the outer circular frame is disposed in the through hole. The outer circular frame includes a first thickness and an engagement segment which is inserted in one of the through holes, and the engagement segment has a second thickness which is less than the first thickness. A shape of a cross-section of the engagement segment mates with the shape of the one of the through hole. Each of the metallic blades is curve-shaped, and each of the metallic blades has an edge along a line of curvature extending between the root and the distal end of the metallic blade. The root is hook-shaped. 
     The present invention further provides a method for manufacturing a fan impeller, comprising: providing a plurality of metallic blades independent from one another; providing a first forming mold; positioning the metallic blades arranged in a radial pattern in the first forming mold; forming in the first forming mold an inner circular frame and an outer circular frame having a spaced, radially outbound relationship with respect to the inner circular frame by means of insert molding, and insert-molding two ends of each of the metallic blades into the inner circular frame and the outer circular frame respectively; providing a rotation shaft unit and a motor circular cover; providing a second forming mold; arranging the rotation shaft unit, the motor circular cover, and the connected inner circular frame, outer circular frame and metallic blades in the second forming mold, so that the inner circular frame surrounds the motor circular cover, and the motor circular cover surrounds the rotation shaft unit; and performing insert molding in the second forming mold to cover the inner circular frame, the motor circular cover, and the rotation shaft unit to form a fan hub. 
     It is preferable that two ends of each of the metallic blades are a root and a distal end respectively, at least a portion of the root is embedded in the fan hub, and at least a portion of the distal end is embedded in the outer circular frame. The distal end forms an engagement member, and the outer circular frame is engaged with the distal end by means of the engagement member. The engagement member can be a retention pin, the retention pin outwardly extends away from a bend of the distal end so that the bend and the retention pin of the distal end, in combination, embeddingly extend in the outer circular frame along a circumference direction of the outer circular frame. The engagement member can be a through hole, and at least a portion of the outer circular frame is disposed in the through hole. The outer circular includes a first thickness and an engagement segment which is inserted in one of the through holes, and the engagement segment has a second thickness which is less than the first thickness, and a shape of a cross-section of the engagement segment mates with the shape of the one of the through holes. Each of the metallic blades is curve-shaped, and each of the metallic blades has an edge along a line of curvature extending between the root and the distal end of the metallic blade. 
     In the fan impeller and the method for manufacturing the same according to the present invention, the metallic blades, the plastic fan hub and the plastic outer circular frame are connected by means of insert molding, so that the number of the blades can be increased to provide increased air output. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the detailed description and the drawings given herein below for illustration only, and thus does not limit the disclosure, wherein: 
         FIG. 1  is a perspective view of a fan impeller according to a first embodiment of the present invention; 
         FIG. 2  is another perspective view of the fan impeller according to the first embodiment of the present invention; 
         FIG. 3  is a radial cross-sectional view of the fan impeller according to the first embodiment of the present invention; 
         FIG. 4  is a transverse cross-sectional view of the fan impeller according to the first embodiment of the present invention; 
         FIG. 5  is a schematic view of the first embodiment of the present invention, illustrating a possible variation of an engagement member of a metallic blade; 
         FIG. 6  is a partial cross-sectional view of the fan impeller according to a second embodiment of the present invention; 
         FIG. 7  is a process flow chart showing a method for manufacturing a fan impeller according to a third embodiment of the present invention; 
         FIG. 8  is a perspective view illustrating a metallic blade provided in the method for manufacturing the fan impeller according to the third embodiment of the present invention; 
         FIG. 9  is a schematic view of the third embodiment of the present invention, illustrating the arrangement of the metallic blades in the method for manufacturing the fan impeller; 
         FIG. 10  is a schematic view of the third embodiment of the present invention, illustrating the metallic blades connected in the method for manufacturing the fan impeller; 
         FIG. 11  is a schematic view of the third embodiment of the present invention, illustrating the arrangement of a motor circular cover and a rotation shaft unit in the method for manufacturing the fan impeller; 
         FIG. 12  is a schematic view illustrating the fan impeller manufactured by using the method for manufacturing the fan impeller according to the third embodiment of the present invention; 
         FIG. 13  is a schematic view of the third embodiment of the present invention, illustrating a different design of the rotation shaft unit in the method for manufacturing the fan impeller; and 
         FIG. 14  is a schematic view of the third embodiment of the present invention, illustrating a different design of the fan impeller in the method for manufacturing the fan impeller. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a first embodiment of the present invention provides a fan impeller comprising a fan hub  100 , an outer circular frame  200 , and a plurality of metallic blades  300 . 
     In the present embodiment, the fan hub  100  is preferably a plastic cap made by insert molding, and the fan hub  100  is a circular fan hub, and the present disclosure is not limited thereto. The outer circular frame  200  is preferably a plastic circular ring made by insert molding. The outer circular frame  200  has a spaced, radially outbound relationship with respect to the fan hub  100 , and is disposed coaxially with the fan hub  100 . 
     Referring to  FIGS. 3 and 4 , each of the metallic blades  300  is preferably an elongated metallic plate made by pressing molding. Each metallic blade  300  can be selectively bent to form a curved shape as required. The metallic blades  300  are independent from one another. The metallic blades  300  can be all of the same type or can be of mixed types. Two ends of each of the metallic blades  300  are a root  310  and a distal end  320  respectively, and as seen in  FIGS. 2 and 4 , each of the metallic blades  300  has an edge  301  along a line of curvature extending between the root  310  and the distal end  320  of the metallic blade  300 . The root  310  is hook-shaped, and at least a portion of the root  310  is embedded in and hook-engaged with the fan hub  100 . In detail, the fan hub  100  is disposed along a longitudinal axis having a first axial end and a second axial end opposite the first axial end. The root  310  has a bend portion having a length, and the bend portion of the root  310  is embedded in the fan hub  100  at a position on the fan hub  100  intermediate the first axial end and the second axial end. At least a portion of the distal end  320  is embedded in the outer circular frame  200 . The metallic blades  300  are secured in position by means of the fan hub  100  and the outer circular frame  200 , so that the metallic blades  300  are arranged in a radial pattern. The present invention does not limit the arrangement of the metallic blades  300  when the metallic blades  300  are of mixed types. 
     The distal end  320  includes a retention pin  322  that outwardly extends away from a bend  321  of the distal end  320  so that the bend  321  and the retention pin  322  of the distal end  320 , in combination, embeddingly extend in the outer circular frame  200  along a circumference direction of the outer circular frame  200 . The retention pin  322  and the bend  321  can be shallowly embedded into the outer circular frame  200  as shown in  FIG. 4  and can be deeply embedded into the outer circular frame  200  as shown in  FIG. 5 , and the present invention is not limited thereto. 
     Referring to  FIGS. 1 and 6 , a second embodiment of the present invention provides a fan impeller comprising a fan hub  100 , an outer circular frame  200 , and a plurality of metallic blades  300 . The structure of the second embodiment is similar to that of the first embodiment, and thus, similarities are omitted for brevity. The present embodiment is different from the first embodiment in that there is a through hole  332  formed on the distal end  320  of each of the metallic blades  300 , and at least a portion of the outer circular frame  200  is disposed in each of the through holes  332 , for example, in a manner so that a portion of the distal end  320  of each of the metallic blades  300  extends radially beyond an outer peripheral edge of the outer circular frame  200 . It is preferable that the outer circular frame  200  includes a first thickness T 1  and engagement segments  210  which respectively engage with the metallic blades  300  having a second thickness T 2  less than the first thickness T 1 , a shape of a cross-section of each of the engagement segments  210  mates with the shape of a respective corresponding one of the through holes  332 , and each of the engagement segments  210  is inserted in a respective corresponding one of the through holes  332 . 
     A third embodiment of the present invention provides a method for manufacturing a fan impeller. In this embodiment, the method for manufacturing the fan impeller comprises steps as follows. 
     Referring to  FIGS. 7 and 8 , in step a, a plurality of metallic blades  300  independent from one another are formed by impact molding. The number of the metallic blades  300  is not intended to be limited by the present invention. The number of the metallic blades  300  is determined depending on the requirement for designing the fan impeller. According to the requirement for designing the fan impeller, each of the metallic blades  300  can be selectively bent to form a desired curved shape. Each of the metallic blades  300  is preferable in an elongated shape. Two ends of each of the metallic blades  300  are a root  310  and a distal end  320  respectively. In the above-mentioned impact molding process, an engagement member is formed at the distal end  320  of each of the metallic blades  300 . In the present embodiment, the engagement member is a retention pin  322  extending from the distal end  320  of each of the metallic blades  300 . The retention pin  322  is bent and disposed corresponding to the outer circular frame  200 . The foregoing description relates to the engagement member in the preferred embodiment, but is not intended to limit the engagement member of the present invention to any particular type or form. The engagement member can be, for example, a through hole  332  as described in the second embodiment. 
     Referring to  FIG. 7 , in step b following step a, a first forming mold (not illustrated) is provided. 
     Referring to  FIGS. 7 and 9 , in step c following the step b, the metallic blades  300  provided in the step a are arranged in a radial pattern and positioned in the first forming mold provided in the step b. 
     Referring to  FIGS. 7 and 10 , in step d following the step c, an inner circular frame  110  and an outer circular frame  200  are formed in the first forming mold by insert molding. The inner circular frame  110  is preferably a plastic circular body, and the outer circular frame  200  is preferably another plastic circular body having a spaced, radially outbound relationship with respect to the inner circular frame  110  and disposed coaxially with the inner circular frame  110 . In the step d, two ends of each of the metallic blades  300  are insert-molded in the inner circular frame  110  and the outer circular frame  200 , respectively. The metallic blades  300  are secured in respective positions with respect to one another by means of the inner circular frame  110  and outer circular frame  200 . At least a portion of the root  310  of each metallic blade  300  is insert-molded in the inner circular frame  110 , and the retention pin  322  of the distal end  320  of each metallic blade  300  is insert-molded in the outer circular frame  200 . Therefore, the outer circular frame  200  is engaged with the distal end  320  of each metallic blade  300  by means of the engagement member. 
     When the engagement member is the through hole  332 , the outer circular frame  200  includes a first thickness T 1  and engagement segments  210  respectively corresponding to the metallic blades  300  having a second thickness T 2  less than the first thickness T 1 , a shape of a cross-section of each engagement segment  210  mates with the shape of a respective corresponding one of the through hole  332 , and each of the engagement segments  210  is inserted in a respective corresponding one of the through holes  332 . 
     Referring to  FIGS. 7 and 11 , step e and step f are executed after the step d, the step e and the step f need not be performed in a particular order. In the step e, a motor circular cover  120  and a rotation shaft unit  130  are provided. The motor circular cover  120  is preferably a circular cover made of metal. The rotation shaft unit  130  can be a metallic rod as shown in  FIG. 11 , or can be a metallic cylinder for insertion of the metallic rod. In the step f, a second forming mold (not illustrated) is provided. In the second forming mold, there are disposed the foregoing connected inner circular frame  110 , outer circular frame  200  and metallic blades  300 , the motor circular cover  120  and the rotation shaft unit  130 . 
     Referring to  FIGS. 7 and 11 , the step g is executed after the execution of the step e and the step f. In the step g, the motor circular cover  120  and the rotation shaft unit  130  provided in the step e are placed in the second forming mold provided in the step f, and the motor circular cover  120  is arranged to surround the rotation shaft unit  130 ; the connected inner circular frame  110 , outer circular frame  200  and metallic blades  300  are arranged in the second forming mold, and the inner circular frame  110  surrounds the motor circular cover  120 . 
     Referring to  FIGS. 7 and 12 , in step h following the step g, insert molding is performed in the second forming mold to cover the inner circular frame  110 , the motor circular cover  120 , and the rod-form rotation shaft unit  130  to form a fan hub  100 . 
     In the method for manufacturing the fan impeller of the present invention, the fan impeller as shown in  FIG. 12  is manufactured by the foregoing steps. The rotation shaft unit  130  is inserted in a corresponding cylinder, so that the fan impeller is rotatable. When the rotation shaft unit  130  is the metallic cylinder, the fan impeller is manufactured as the fan impeller shown in  FIG. 14 . The rotation shaft unit  130  is provided for insertion of a corresponding rod, so that the fan impeller is rotatable. 
     By using the above-mentioned method for manufacturing the fan impeller, the fan impeller of the present invention, which has the metallic blades, can be manufactured. The metallic blades possess greater structural strength than the conventional plastic blades, and a metallic material can be manufactured into a thinner blade than plastic. Therefore, the fan impeller can include more blades, thereby increasing an air mass flow rate. Accordingly, compared to the conventional plastic fan impeller, the present invention achieves superior heat-dissipation efficiency. 
     It is to be understood that the above descriptions are merely the preferable embodiments of the present invention and are not intended to limit the scope of the present invention. Equivalent changes and modifications made in the spirit of the present invention are regarded as falling within the scope of the present invention.