Abstract:
The present invention relates a vibration generating motor providing simple and fast assembly, and ready recycling. A motor includes a plurality of rotors around a rotary shaft, a plurality of coil winding portions on respective rotors, and a coil on each respective coil winding portion. At least a two part weight is positioned between selected coil winding portions and has an seperably upper and lower part, allowing weight maximization at low cost while conserving space.

Description:
BACKGROUND TO THE PRESENT INVENTION 
     1. Field of the Invention 
     The present invention relates to a vibration generating motor. More specifically the present invention relates to vibration generating motors which enable easy use in cellular phones, pagers, entertainment game controllers and other consumer products requiring small and effective vibration generating motors. 
     2. Description of the Related Art 
     Referring now to FIGS. 8 and 9, a conventional vibration generating motor  1  includes a plurality of rotors  3 , rotatable about a rotary shaft  2 . A magnet (not shown) surrounds the plurality of rotors  3 , as in known small-sized DC motors. 
     Each rotor  3  includes a rotary core  4 , each having respective coil winding portions  4   a,    4   b,  and  4   c,  as shown. Respective coils  5   a,    5   b,  and  5   c  are wound upon respective coil winding portions  4   a,    4   b,  and  4   c,  as shown. 
     During use, a DC voltage is applied to coils  5   a,    5   b  and  5   c  by way of a spring(not shown), disposed on rotary shaft  2 . Under the influence of the DC voltage, rotors  3  are driven by the interrelation of a magnetic flux (not shown) generated on coils  5   a , 5   b  and  5   c  and a magnetic flux of the magnet. 
     During assembly, a weight  6  is inserted and fixed between selected neighboring coil winding portions, ( 4   a  and  4   c,  as shown for example). 
     Weight  6  is specifically designed with a rectangularly columnar body  6   a  to fit specifically in the profile of the space formed between core winding portions  4   a,    4   c.  A step  6   b,  projected in two directions from an end of columnar body  6   a,  is specifically designed to aid fitting in the profile space formed. 
     When weight  6  is inserted between coil winding portions  4   a  and  4   c,  step  6   b  contacts each winding portions  4   a,    4   c  and weight  6  is thereby axially positioned therebetween. One end of weight  6  is fixed by clinching, or another similar operation, while an opposite end of weigh  6  is fixed in place by an adhesive such as a chloroprene rubber adhesive. 
     As noted above, during operation, rotors  3  are driven when respective coils  5   a,    5   b  and  5   c  are energized. Since weight  6  is fixed between coil winding portions  4   a  and  4   c,  a center of rotational gravity of plurality of rotors  3  is deviated, in eccentric state, from a center axis of rotary shaft  2 . Accordingly, due to rotation of rotors  3 , conventional vibration generating motor  1  as a whole generates vibration. 
     Unfortunately, weight  6  in conventional vibration generating motor  1  is strongly fixed by an adhesive agent between coil winding portions  4   a  and  4   c  of core  4  to resist unplanned separation. This is detrimental to cost, speed, and efficiency, since in an a conventional assembling process a hardening furnace for hardening the strong adhesive agent is required and the hardening time necessarily lengthens the production process. 
     Consequently, the production cost of conventional motors is detrimentally expensive. As a further detriment, in conventional vibration generating motor  1  it is not easy to remove weight  6  from core  4  and thereby recycle used weights  6 . This prevents or severely limits recycling and increases manufacturing waste. 
     It is also know that instead of the adhering process shown, it is possible to fix weight  6  between coil winding portions  4   a  and  4   c  by a welding process. Unfortunately welding processes, require welding equipment and a welding time, thus providing similar production disadvantages. As further disadvantages to a welding process, the heat generated during welding frequently deforms rotary cores  4 , and recycling weight  6  is similarly prevented. 
     OBJECT AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a vibration generating motor which overcomes the detrimental designs provided above and provides reduced costs and increased production efficiencies. 
     It is another object of the present invention to provide a vibration generating motor which can be assembled in an easy manner with reliable attachment. 
     It is another object of the present invention to provide a vibration generating motor wherein an eccentric weight can be easily recycled. 
     It is another object of the present invention to provide a device which maximizes the available space between adjacent rotors while providing secure assembly and reliable operation. 
     Briefly stated, the present invention relates to a vibration generating motor providing simple and fast assembly, and ready recycling. A motor includes a plurality of rotors around a rotary shaft, a plurality of coil winding portions on respective rotors, and a coil on each respective coil winding portion. At least a two part weight is positioned between selected coil winding portions and has an seperably upper and lower part, allowing weight maximization at low cost while conserving space. 
     According to one embodiment of the present invention, there is provided a vibration generating motor comprising: at least a first, a second, and a third rotor operable about a rotary shaft, a coil winding portion on respective each the rotor, a plurality of coils wound on respective each the coil winding portion, a weight member, the weight member having a shape enabling selective and fixable positioning at a first position between two adjacent ones of the at least first, second, and third rotors during an assembly of the motor, the weight member including an upper part and a lower part, the upper part including an upper body and a first and a second upper flange, the lower part including a lower body and a first and a second lower flange, means for seperably coupling the upper and the lower parts of the weight member during the assembly, the upper body and the lower body contacting during the assembly, the first and the second upper flanges contacting a top surface of the coil winding portions on respective the two adjacent ones, and the first and the second lower flanges contacting a bottom surface of the coil winding portions on respective the two adjacent ones, whereby the means for separably coupling securely joins the weight member to the adjacent ones and enables a rapid assembly and secure operation of the motor. 
     According to another embodiment of the present invention there is provided a vibration generating motor, wherein: the means for separably coupling includes at least a first upper inserting opening on the upper body extending in an axial direction of the motor, the means for separably coupling further includes at least a first lower inserting opening in the lower body extending coaxial with the first inserting opening, and a the means for separably coupling including at least a first rivet member passing through the first upper and the first lower inserting openings and fixing the upper and lower parts together during the assembly, whereby an assembly time and an assembly cost are easily reduce for the motor. 
     According to another embodiment of the present invention there is further provided a vibration generating motor, wherein: the first upper inserting opening has a first diameter, an upper recess on a top surface of the upper part has a second diameter larger than the first diameter, the first lower inserting opening has a third diameter, a lower recess on a bottom surface of the lower part has a fourth diameter larger than the third diameter, and the upper and the lower recess receive a first and a second enlarged portion of the rivet during the assembly. 
     According to another embodiment of the present invention there is further provided a vibration generating motor, wherein: the means for separably coupling includes a locking hole portion axially positioned in the upper body, the means for separably coupling includes a locking protrusion axially extending from the lower body, the locking hole and the locking protrusion being coaxial, and the locking protrusion locking into the locking hole portion during the assembly and removably fixing the upper part and the lower part together. 
     According to another embodiment of the present invention there is provided a vibration generating motor, wherein: the weight member has a shape matching an interior surface of the two adjacent ones bounding the weight member, whereby the shape of the weight member maximizes a mass eccentric to the rotary shaft and within a circumference of the rotors. 
     According to another embodiment of the present invention there is a method of assembling a vibration generating motor, comprising the steps of: providing at least a first, a second, and a third rotor operable about a rotary shaft, providing a coil winding portion on respective each the rotor, providing a plurality of coils wound on respective each the coil winding portion, providing a weight member having an upper and a lower part, the upper part including an upper body and a first and a second upper flange, the lower part including a lower body and a first and a second lower flange, positioning the lower part at a first position between two adjacent ones of the at least first , second, and third rotors, positioning the upper part on the lower part in the first position and contacting a top surface of the upper body with a bottom surface of the lower body, and seperably coupling the upper part and the lower part, whereby the first and second upper flanges contact a top surface of the coil winding portions on respective two the adjacent ones, and the first and second lower flanges contact a bottom surface of the coil winding portions and securing the weight member to the adjacent ones. 
     According to an embodiment of the present invention, there is provided a vibration generating motor, in which each of the upper and lower parts of the weight has an opening formed in an axial direction of the rotary shaft and a rivet is inserted in the opening to fix the weight between the two neighboring coil winding portions. 
     According to another embodiment of the present invention, there is a vibration generating motor, in which two enlarged portions of the rivet are incorporated into two recesses formed in the upper and lower parts of the weight. 
     According to another embodiment of the invention, there is a vibration generating weight provided in which the upper and lower parts of the weight include an inserting hole and a protrusion on respectively opposing surfaces of the upper and lower parts mutually engageable during assembly and effective to join the upper and lower parts together. 
     The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially cutaway section view showing a first embodiment of a vibration generating motor according to the present invention. 
     FIG. 2 is a front view of a plurality of rotors in FIG.  1 . 
     FIG. 3 is a partially cutaway section view taken along line I—I X in FIG.  2 . 
     FIG.  4 (A) is a rear view of an upper part of a weight used in FIG.  2 . 
     FIG.  4 (B) is a plan view of the upper part of the weight in FIG.  4 (A). 
     FIG.  4 (C) is a front view of the upper part of the weight in FIG.  4 (A). 
     FIG.  4 (D) is a vertical section view of the upper part of the weight in FIG.  4 (A). 
     FIG.  5 (A) is a front view of a lower part of the weight used in FIG.  2 . 
     FIG.  5 (B) is a plan view of the lower part of the weight in FIG.  5 (A). 
     FIG.  5 (C) is a rear view of the lower part of the weight in FIG.  5 (A). 
     FIG.  5 (D) is a vertical section view of the lower part of the weight in FIG.  5 (A). 
     FIG. 6 is a front view of a plurality of rotors showing a second embodiment a vibration generating motor according to the present invention. 
     FIG. 7 is a partially cutaway section view of a plurality of rotors taken long line II—II in FIG.  6 . 
     FIG. 8 is a schematic front view of a conventional vibration generating motor. 
     FIG. 9 is a schematic perspective view of a weight used in FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 1 to  3 , a vibration generating motor  10  includes a plurality of rotors  12  rotatable about a rotary shaft  11  within a case  10   a,  and a magnet  13  positioned around the plurality of rotors  12 . 
     Each rotor  12  constitutes a core  14 . Vibration generating motor  10  includes at least three cores  14 , each core  14  having respective winding portions  14   a,    14   b,  and  14   c,  as shown. 
     Three coils  15   a,    15   b  and  15   c  are wound on respective coil winding portions  14   a,    14   b  and  14   c.  During operation, when certain DC voltage is applied to coils  15   a,    15   b  and  15   c,  by way of a slop spring  16  disposed on rotary shaft  11 , the plurality of rotors  12  are driven by the interrelation of a magnetic flux generated in coils  15   a,    15   b  and  15   c  as well as a magnetic flux of magnet  13 . 
     A weight  20  is inserted and fixed in a space formed between two neighboring coil winding portions, shown here as winding portions  14   a  and  14   b.    
     Weight  20  is most preferably made of a high strength and weigh material e.g. a high gravity tungsten. 
     As shown in FIG. 3, weight  20  is divided into an upper part  21  and a lower part  22  relative to a center axis of rotary shaft  11 . 
     Additionally referring now to FIGS.  4 (A),  4 (B), and  4 (c), upper part  21  of weight  20  includes an upper body  21   a,  formed extended upwardly from a middle position of a center axis, and two flanges  21   b,    21   b  respectively extended radially from upper body  21   a.  An inserting opening  21   c  penetrates axially into body  21   a.  A recess  21   d,  having a diameter greater than a diameter of inserting opening  21   c,  is on a top portion of upper part  21 . 
     During assembly, when upper part  21  of weight  20  is inserted upwardly between selected coil winding portions (shown as coil winding portions  14   a  and  14   b ) of core  4 , upper body  21   a  penetrates into a space defined and formed between coil winding portions  14   a  and  14   b.  Flanges  21   b,    21   b  contact a top surface of two respective coil winding portions  14   a,    14   b,  as shown. 
     During assembly, when joining upper and lower parts  21 ,  22  of weight  20 , a rivet  23  is inserted into inserting opening  21   c  and an upper end  23   a  of rivet  23  is enlarged radially by clinching and suitably incorporated into recess  21   d.  Upper body  21   a  includes a cutaway portion  21   e  to avoid a conflict with a riser(not shown) of each rotor  12 . 
     Referring to FIGS.  5 (A),  5 (B) and  5 (C), lower part  22  of weight  20  includes a lower body  22   a  extended downwardly from a middle position of the axis, and two flanges  22   b,    22   b  extending radially from an end of lower body  22   a.    
     After or during assembly, an inserting portion  22   c  penetrates axially into lower body  22   a.  A recess  22   d  is formed adjacent inserting opening  22   c,  and has a diameter larger than a diameter of inserting opening  21   c.    
     During assembly, when lower part  22  of weight  20  is inserted between coil winding selected winding portions  14   a,    14   b  downwardly, lower body  22   a  penetrates into a space formed between coil winding portions  14   a,    14   b.    
     During assembly, flanges  22   b,    22   b  contact a lower end of respective coil winding portions  14   a,    14   b.  During fixing between upper and lower parts  21 ,  22  of weight  20 , a means for coupling upper and lower parts  21 ,  22 , such as rivet  23  (or a bolt or instant-glue(all not shown)), is inserted into inserting opening  22   c  and a lower end  23   b  is enlarged radially by clinching and suitably incorporated into recess  22   d.    
     Under the embodiment described, flanges  21   b,    21   b  of upper part  21  and flanges  22   b,    22   b,  of lower part  22 , hold coil winding portions  14   a,    14   b  in an axial direction, and firmly fix weight  20  fixed between selected core winding portions  14   a,    14   b.    
     Under the present embodiment, when coils  15   a,    15   b  and  15   c  of respective rotors  3  are energized by slip spring  16 , rotors  3  are driven about rotary shaft  11 . Since weight  20  is inserted and fixed between selected coil winding portions (here shown as winding portions  14   a  and  14   b ), a center of gravity of the plurality of rotors  12  is deviated eccentrically from a center of rotary shaft  11 . Consequently, when rotors  12  are driven, vibration generating motor  10  as a whole generates vibration. 
     According to another beneficial aspect of the present invention, weight  20  is inserted and simply and quickly fixed by use of securing or coupling means, such as rivet  23 , between coil winding portions  14   a  and  14   b  of each core  14 . Thus, welding work is not necessary, and production costs and time for motor  10  can be reduced. Additionally, since it is easy to remove upper and lower parts  21 ,  22  of weight  20  by quickly removing rivet  23 , it is possible to rapidly recycle used weights, thereby saving time, money, and reducing material waste. 
     Additionally referring now to FIGS. 6 and 7, a second embodiment of the present invention includes an alternatively designed weight  30 . Similar to the above-described embedment, weight  30  is inserted and fixed in a space formed between two adjacent coil winding portions, (shown here as winding portions  14   a  and  14   b ). Weight  30  is constructed of a similar material as weight  20 . 
     Weight  30  is divided into an upper part  31  and a lower part  32  at a middle position of an axis of the plurality of rotors  12 . 
     Upper part  31  of weight  30  similarly includes body  21   a  and two flanges  21   b,    21   b  and cutaway portion  21   e,  as described above. 
     Upper part  31  includes a locking hole  31   a,  instead of inserting opening  21   c  and recess  21   d  of the first embodiment (shown in FIG.  4 (D)). 
     Lower part  32  of weight  30  similarly includes body  22   a  and two flanges  22   b,    22   b,  as described above. 
     Lower part  32  includes a locking protrusion  32   a  instead of inserting opening  22   c  and recess  22   d  (shown in FIG.  4 (D)). Locking protrusion  32   a  has a shape designed to lock within locking hole  32   b  during assembly while allowing ready separation during a disassembly. 
     As designed, body  21  a of upper part  31  opposes body  22   a  of lower part  32 , and allows easy locking of protrusion  32   a  can be easily locked into hole  32   b.  As similarly noted above, since neither adhesive nor welding is required, production cost and times may be reduced substantially. In the present embodiment, upper and lower parts  31 ,  32  of weight  30 , after fixing, hold coil winding portions  14   a,    14   b  in an axial direction, and fix weight  30  between coil winding portions  14   a,    14   b.    
     As in the first embodiment, when coils  15   a,    15   b  and  15   c  of the plurality of rotors  3  are energized by slip spring  16 , rotors  3  are operably driven about rotary shaft  11 . Since weight  30  is fixed between selected coil winding portions (shown as winding portions  14   a  and  14   b  here), the center of gravity of rotors  12  is eccentric from the center of rotary shaft  11 . Accordingly, during operation, motor  10 , as a whole, generates vibration. 
     In the foregoing embodiments, the plurality of rotors comprise three coil winding portions, but this invention may be applied for a small-sized DC motor having two or four or more coil winding portions. 
     As discussed, weights  20 ,  30  are inserted and fixed and designed to correspond to the profile of a space formed between selected neighboring coil winding portions of the plurality of rotors  12 . The outer surface of either selected weight  20 ,  30  contacts an inner surface of the respective two neighboring coil winding portions as well as the surface of the respective neighboring coils. Consequently, the design allows weight maximization utilizing the selected space between two neighboring coil winding portions. Thus, vibration may be maximized, while reducing or minimizing size and increasing reliability, speed, and economy. 
     Although only a single or few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiment(s) without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the spirit and scope of this invention as defined in the following claims. 
     In the claims, means- or step-plus-function clauses are intended to cover the basic structures described or suggested herein as performing the recited function and not only structural equivalents but also equivalent structures. Thus, for example, although a nail, a screw, and a bolt may not be structural equivalents in that a nail relies entirely on friction between a wooden part and a cylindrical surface, a screw&#39;s helical surface positively engages the wooden part, and a bolt&#39;s head and nut compress opposite sides of at least one wooden part; in the environment of fastening wooden parts, a nail, a screw, and a bolt, or even adhesive, may be readily understood by those skilled in the art as equivalent structures and provide equivalent means to achieve the stated and intended function, as long as at least one structure is described. 
     Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.