Patent Publication Number: US-2010117471-A1

Title: Micro vibration motor with adjustable vibration amount

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 097220054 filed in Taiwan, R.O.C. on Nov. 7, 2008, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a micro motor, and more particularly to a micro vibration motor with adjustable vibration amount. 
     2. Related Art 
     Recently, micro vibration motors have been widely applied in people&#39;s life with the advent of digital era and aging of population. The most notable application is in the mobile phone. When a call is coming, the mobile phone generally has two types of modes to alert users, one is the ring tone mode, and the other is the mute vibration mode. When a mobile phone is set to the vibration mode, the micro vibration motor must be used to generate the vibration. The micro vibration motor is also used in other digital mobile devices, entertaining game players, and handheld game players. Along with the fierce competition in the industry of producing entertaining devices, providing merely video and audio effects can no longer satisfy changeful tastes of consumers, and thus some manufacturers have provided consumers with touch stimulation in the entertaining devices. For example, the Immersion Co. of the US has a number of patents that use touch technology on computer peripherals, such as a vibration mouse, a vibration keyboard, and a vibration joy stick on game player. In order to implement the touch mechanisms, the vibration can also be generated by the vibration motor. 
     In response to the demands of market, the design concept of short, small, light, and thin has become a current trend. The size of the micro vibration motor disposed in a light and thin mobile phone must be reduced accordingly. However, the reduced volume of the motor results in the increased cost due to that the parts having the reduced sizes are not easily assembled. Further, an offset of a rotor cannot be too large due to the limit of the size, such that a vibration amount of the micro vibration motor cannot be increased, and the user quite easily neglects the vibration alert of the incoming call of the mobile phone if being not quite careful. 
     In terms of means of generating vibration amount, U.S. Pat. No. 6,836,039 discloses a technique that comprises an annular magnet with six planar poles. A weight object is added to one side so that the rotor has a gravity center eccentric to its rotation center, so as to generate the vibration. However, the design increases the load of the rotor, so more input electric energy is needed. Moreover, adding the weight object makes the volume of the motor higher, and thus it is difficult to miniaturize the motor. U.S. Pat. No. 6,573,627 discloses a technique that comprises an annular magnet with four planar poles located eccentrically on a rotor disk. When the rotor disk rotates, the eccentric gravity center of the rotor causes vibration. However, due to space limit, the eccentricity between the annular magnet and the rotation center is limited. As a result, the increasing of the vibration amount is limited. 
     SUMMARY OF THE INVENTION 
     In the above patents, the conventional micro vibration motors still have complicated structures, and the complexity of windings of induction coils is disadvantageous to the production of the micro vibration motors and the demands of miniaturization or microminiaturization. Therefore, the present invention is a micro vibration motor with adjustable vibration amount, in which the vibration amount of the micro vibration motor is changed through a structural design capable of adjusting weight, so as to perform an optimal and maximum adjusting application in a limited space, thereby satisfying various design demands. 
     The present invention provides a motor with adjustable vibration amount, which comprises a rotor and a stator, and the rotator rotates on the stator. The rotor comprises a round cover; a perforation, formed on a rotation center of the round cover; a weight portion, integrally formed on an edge of the round cover, for changing a mass center of the round cover, in which the weight portion has at least one slot formed thereon; and at least one movable part, selectively disposed in each slot, for changing a weight of the weight portion, so as to adjust a vibration amount generated during the rotation of the round cover. 
     In the micro vibration motor with adjustable vibration amount, a weight structure capable of performing a fine tuning is designed on the rotor, and is selectively combined with the movable part, such that most flexible adjustment may be made according to practical product design demands, thereby performing the optimal and maximum adjusting application in the limited space. In addition, the present invention adopts an integrally formed structure, so as to have advantages such as a high strength, a small number of parts, a simple structure, a simple assembly, and a low cost, thus becoming an optimal design of the micro vibration motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given herein below for illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a schematic cross-sectional structural view of a micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 2  is a schematic structural view of a rotor of the micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 3  is a top view of the rotor of the micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 4  is a cross-sectional view of the rotor of the micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 5  is a schematic structural view of a stator of the micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 6  is a top view of the stator of the micro vibration motor with adjustable vibration amount according to the present invention; 
         FIG. 7  is a cross-sectional view of the stator of the micro vibration motor with adjustable vibration amount according to the present invention; and 
         FIG. 8  is a top view of a rotor of a micro vibration motor with adjustable vibration amount according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a schematic cross-sectional structural view of a micro vibration motor with adjustable vibration amount according to the present invention. Referring to  FIG. 1 , the micro vibration motor  300  according to the present invention comprises a rotor  100  and a stator  200 , in which the rotor  100  rotates on the stator  200 . An induction coil, a magnetic element, and a spindle in  FIG. 1  are not key points of the present invention, and a detailed structure of the micro vibration motor  300  (such as the induction coil, the magnetic element, and a circuit board) may be obtained with reference to US Publication Patent No. 20020195890, so it is not described in detail in the following. 
       FIG. 2  is a schematic structural view of the rotor of the micro vibration motor with adjustable vibration amount according to the present invention. Next, referring to  FIG. 2 , the rotor  100  according to the present invention comprises a round cover  10 , a perforation  20 , a weight portion  30 , and a movable part  40 . 
     The round cover  10  is mainly made of a magnetic material (metal material such as iron, cobalt, and nickel). 
     The perforation  20  is formed on a rotation center of the round cover  10 . The perforation  20  enables the rotor  100  to sleeve on a spindle (not shown) coaxially. 
     The weight portion  30  is integrally formed on an edge of the round cover  10 , for changing a mass center of the round cover  10 . The weight portion  30  has nine slots  31  formed thereon (the number of the slots  31  may be increased or reduced and positions of the slots  31  may be adjusted according to design demands). The relative slots  31  punched on the weight portion  30  may be in a shape of round, square, triangle, and other random geometrical shapes corresponding to a shape of the movable part  40 . 
     The movable part  40  may be selectively disposed in each slot  31 , for changing a weight of the weight portion  30 , so as to adjust the vibration amount generated during rotation of the round cover  10 . With a current mechanical manufacturing technology, in the procedure of manufacturing the rotor  110 , a plurality of relative slots  31  is punched on the weight portion  30 , so as to form the detachable movable part  40  on the weight portion  30 , such that it is quite easy in manufacturing. Alternatively, the movable part  40  is manufactured in an additional processing manner, and the movable part  40  may be, for example, a countersunk head screw  41 , a nail  42 , a cotter  43 , or a latch. When the movable part  40  is the countersunk head screw  41 , the slots  31  need to have screw threads. 
     When it intends to increase the vibration amount, one or more movable parts  40  may be selectively disposed in the slots  31  of the weight portion  30 , so as to increase the weight of the weight portion  30 , in this manner, an entire gravity center is further eccentric to the rotation center, so as to further increase the vibration amount generated during the rotation of the round cover  10 . When it intends to reduce the vibration amount, one or more movable parts  40  may be selectively removed from the slots  31  of the weight portion  30 , so as to reduce the weight of the weight portion, in this manner, the vibration amount generated during the rotation of the round cover  10  is reduced. Therefore, according to the design of the present invention, the vibration amount may be adjusted depending on the practical application product demands. 
     Therefore, the micro vibration motor  300  according to the present invention may be applied to various electronic products (for example, a personal digital assistant (PDA), a mobile phone, or a global positioning system (GPS) etc.). Under a design trend of short, small, light, and thin, in the present invention, through the rotor  100  structure capable of fine-tuning the vibration amount, the vibration amount of the micro vibration motor  300  may be increased in a limited space, which fully satisfies the diversified design demands of various electronic products. 
       FIG. 3  is a top view of the rotor of the micro vibration motor with adjustable vibration amount according to the present invention. Referring to  FIG. 3 , the weight portion  30  in the rotor  100  according to the present invention is schematically in a shape of a bracket “)”. The weight portion  30  is used to change the mass center of the round cover  10 , such that the rotor  100  generates the vibration when rotating. 
       FIG. 4  is a cross-sectional view of the rotor of the micro vibration motor with adjustable vibration amount according to the present invention. Referring to  FIG. 4 , the weight portion  30  according to the present invention is integrally formed on the edge of the round cover  10 , such that it is quite easy in manufacturing, thus having advantages such as an easy manufacturing, a high strength, a small number of parts, a simple structure, a simple assembly, and a low cost. 
       FIG. 5  is a schematic structural view of the stator of the micro vibration motor with adjustable vibration amount according to the present invention. Referring to  FIG. 5 , the stator  200  according to the present invention comprises a spindle seat  120 , a first long hole  130 , a second long hole  140 , and a fixing portion  150 . 
     The stator  200  is schematically a round disc structure, and an inner diameter of the round cover  10  of the rotor  100  is smaller than an inner diameter of the round disc structure of the stator  200 . The first long hole  130  and the second long hole  140  are opened on a bottom surface  110  of the stator  200 . A perforation  151  is formed in the fixing portion  150 . The stator  200  is fixed in various electronic products (not shown) through the perforation  151  on the fixing portion  150  together with a fixing part (not shown). 
       FIG. 6  is a top view of the stator of the micro vibration motor with adjustable vibration amount according to the present invention. Referring to  FIG. 6 , the first long hole  130  in the stator  200  according to the present invention is a wholly hollow structure, and the second long hole  140  is a partially hollow structure. Referring to  FIG. 7 , a cross-sectional view of the stator of the micro vibration motor with adjustable vibration amount according to the present invention is shown. 
       FIG. 8  is a top view of a rotor of a micro vibration motor with adjustable vibration amount according to another embodiment of the present invention. Referring to  FIG. 8 , slots  31  in a weight portion  30  according to another embodiment of the present invention are rectangular. 
     To sum up, in the micro vibration motor with adjustable vibration amount according to the present invention, the weight structure capable of performing a fine tuning is designed on the rotor, and is selectively combined with the movable part, such that the most flexible adjustment may be made according to practical product design demands, thereby performing the optimal and maximum adjusting application in the limited space. In addition, the present invention adopts an integrally formed structure characteristic, so as to have advantages such as a high strength, a small number of parts, a simple structure, a simple assembly, and a low cost, thus becoming an optimal design of the micro vibration motor.