Abstract:
A linear vibration motor for fixing a ring-shaped coil provided within the linear vibration motor using a simpler structure. A linear vibration motor in which an upper casing and a bracket are configured to have an integrated shape and fixed to the inside or upper side of the coil to form magnetism, thereby facilitating fabrication due to a simple structure, preventing a reduction of a vibration power through a small space, and minimizing a rise of a material cost. Accordingly, the coil within the internal space of the casing is stably fixed by providing a structure for fixing the coil through the simple process of the bracket itself. Furthermore, since parts forming the vibration motor and the linear vibration motor are integrated, an assembly process is simplified, performance is satisfied by realizing a reduced production cost, and a working process and price competitiveness is secured.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims the benefit of Korean Patent Application No. 10-2016-0090243, filed in the Korean Intellectual Property Office on Jul. 15, 2016, the entire content of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
     1. Technical Field 
       [0002]    The present invention relates to a linear vibration motor providing a configuration capable of fixing a coil of a ring shape provided within the linear vibration motor using a simpler structure. 
       2. Description of Related Art 
       [0003]    Recently, as the market of a mobile device is expanded, various technologies which may be implemented in the mobile device are developed. A haptic function applied to the mobile device is one of the technologies. Recently, the size of the entire device is reduced through the improvement of an internal structure, such as a reduction in the size of a vibration generation device that implements the haptic function and a reduction in the thickness thereof. 
         [0004]    For example, a conventional technology, such as Patent Document 1, has adopted a configuration in which a yoke of a T shape is coupled to a bracket forming a vibration generation device in order to secure a sufficient vibration power and also to prevent the size of the vibration generation device from being excessively increased. 
         [0005]    However, such a conventional technology has problems in that it requires an additional process for the bracket in order to connect the yoke to the bracket, a lot of man power and time are required because the yoke suitable for the condition of the bracket must be separately fabricated, and a production cost is increased because the number of parts forming the inside of the vibration generation device is increased. 
         [0006]    Accordingly, there is a need for a technology capable of reducing the number of parts forming the inside of a vibration generation device, simplifying an assembly process, and reducing a production cost. 
       PRIOR ART DOCUMENT 
     Patent Document 
       [0007]    (Patent Document 1) KR 1101330 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to stably fix a coil provided in the internal space of a casing by providing a structure for fixing the coil through the simplification of a process of processing a bracket itself, to simplify an assembly process by integrating parts that form a vibration motor and a linear vibration motor, to satisfy performance by realizing a reduction of a production cost, and to secure a working process and price competitiveness. 
         [0009]    A linear vibration motor according to an embodiment of the present invention includes a casing  2  configured to have an internal space and to include a circular casing center extension part  21  which is disposed at the center and has a shape downward extended in multiple stages, a bracket  3  coupled to the bottom of the casing  2  to form an external appearance of the linear vibration motor and configured to include a circular bracket center extension part  31  which is disposed at the center and has a shape upward extended in multiple stages, a circular coil  4  configured to fix the lateral surfaces of the casing center extension part  21  and the bracket center extension part  31  by coupling the casing center extension part  21  and the bracket center extension part  31 , an elastic body  5  configured to have one side fixed to one, surface on the inside of the casing  2  and the other side coupled to a vibrator  7 , and an FPCB  6  fixed to one surface on the top of the bracket  3  and configured to electrically connect the coil and an external device. 
         [0010]    A processed part  211 ,  311  cut, in a specific shape may be disposed in the center extension part  21 ,  31  of at least any one of the casing center extension part  21  and the bracket center extension part  31 . 
         [0011]    At least one processed part  211 ,  311  may be disposed in a circumferential direction along the lateral side of the center extension part  21 ,  31 . 
         [0012]    Furthermore, the end parts  212  and  312  of the casing center extension part  21  and the bracket center extension part  31  may come into contact with each other or may have a gap  8  of 0.2 mm or less. 
         [0013]    In this case, the elastic body may have one side fixed to one surface on the upper side of the bracket  3  and the other side. 
         [0014]    Additionally, the vibrator  7  may include a magnet  71  of a ring shape, a weight body  72  of a ring shape coupled to the lateral surface of the magnet, an upper yoke  73  disposed on the top of the magnet, and a lower yoke  74  disposed at the bottom of the magnet. 
         [0015]    The magnet  71  may include one magnet or may have a structure in which an upper magnet  711  and a lower magnet  712  are coupled. 
         [0016]    Furthermore, wherein the vibrator  7  may further include a central yoke  75  disposed between the upper magnet  711  and the lower magnet  712 . 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is, a cross-sectional view of a linear vibration motor including the center extension parts of a casing and a bracket according to an embodiment of the present invention. 
           [0018]      FIG. 2  is a perspective view of the center extension parts of the casing and the bracket according to an embodiment of the present invention. 
           [0019]      FIG. 3  shows a magnetic force formed between the magnet and the extension parts when the processed parts shown in  FIG. 2  are absent. 
           [0020]      FIG. 4  is an enlarged view of a cross-section of the center extension parts of the casing and the bracket and a coil coupled to the center extension parts according to an embodiment of the present invention. 
           [0021]      FIG. 5  shows that the center extension parts of the present invention is formed in an overlapping structure. 
           [0022]      FIG. 6  is a cross-sectional view of a linear vibration motor including the center extension parts of the casing and the bracket according to an embodiment of the present invention. 
           [0023]      FIG. 7  is a cross-sectional view of a linear vibration motor including the center extension parts of a casing and a bracket according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Hereinafter, some embodiments of the present invention are described in detail with reference to illustrative drawings. It is to be noted that in assigning reference numerals to elements in the drawings, the same reference numerals denote the same elements throughout the drawings even in cases where the elements are shown in different drawings. Furthermore, in describing the embodiments of the present invention, a detailed description of the known functions and constitutions will be omitted if it is deemed to make the gist of the present invention unnecessarily vague. 
         [0025]    Furthermore, in describing the elements of the present invention, terms, such as the first, the second, A, B, (a), and (b), may be used. However, although the terms are used only to distinguish one element from the other element, the essence, order, or sequence of the elements is not limited by the terms. When it is said that one element is “connected”, “combined”, or “coupled” to the other element, the one element may be directly connected or coupled” to the other element, but it should also be understood that a third element may be “connected”, “combined”, or “coupled” between the two elements. 
         [0026]      FIG. 1  is a cross-sectional view of a linear vibration motor including the center extension parts of a casing and a bracket according to an embodiment of the present invention. 
         [0027]    A basic structure of a linear vibration motor  1  according to an embodiment of the present invention is described in detail with reference to  FIG. 1 . 
         [0028]    For reference,  FIG. 1  shows only the half of the linear vibration motor having a symmetrical structure. This is for clearly showing an internal structure of the linear vibration motor. Accordingly, it should be understood that the remaining half of the linear vibration motor omitted in the drawing has been extended from the illustrated structure having a symmetrical form. It is to be noted that such a symmetrical form is omitted in other drawings in the same manner. 
         [0029]    It may be seen that the linear vibration motor of  FIG. 1  includes a casing  2  configured to perform a cover function on the upper side and a bracket  3  configured to perform a function of supporting the bottom surface. 
         [0030]    More specifically, the linear vibration motor  1  may include the casing  2  configured to have an internal space and to include a circular casing center extension part  21  which is disposed at the center and has a shape downward extended in multiple stages, the bracket  3  coupled to the bottom of the casing  2  to form an external appearance of the linear vibration motor and configured to include a circular bracket center extension part  31  which is disposed at the center and has a shape upward extended in multiple stages, a circular coil  4  configured to fix the lateral surfaces of the casing center extension part  21  and the bracket center extension part  31  by coupling the casing center extension part  21  and the bracket center extension part  31 , an elastic body  5  configured to have one side fixed to one surface on the inside of the casing  2  and the other side coupled to a vibrator  7 , and an FPCB  6  fixed to one surface on the top of the bracket  3  and configured to electrically connect the coil and an external device. 
         [0031]    The center extension part  21 ,  31  may be fabricated in such a way as to be inward pressed in using a press or deep drawing method. Accordingly, a structure capable of stably fixing the coil  4  can be implemented by a single simple process. 
         [0032]    Furthermore, the center extension part  21 ,  31  has a structure extended into the coil  4  downward and upward. Accordingly, an electromagnetic field can be generated in a relation with the coil  4  without a separate yoke assembly. 
         [0033]    Accordingly, there are effects in that a product structure can be simplified, productivity can be improved and a manufacturing cost can be reduced by providing the structure for fixing the coil  4  through a simple press process. 
         [0034]    In this case, the coil  4  may be fixed to have a ring shape on the outside of the casing and the bracket center extension parts  21  and  31  press-in-processed to be identical with the size of the coil, but may be attached and fixed outside the casing and the bracket center extension parts  21  and  31  through a separate adhesive material. 
         [0035]      FIG. 2  is a perspective view of the center extension parts of the easing and the bracket according to an embodiment of the present invention. 
         [0036]    As shown in  FIG. 2 , processed parts  211  and  311  that have been cut in a specific shape may be disposed in the casing and the extension parts of the bracket center extension parts  21  and  31 . 
         [0037]    The role of the processed parts  211  and  311  is described below. As shown in  FIG. 3 , if the processed parts are not present, when a magnet  71  moves up/down, magnetism is formed between the magnet  71  and the extension parts  21  and  31  not including the processed parts  212  and  213 . Accordingly, there is a problem in that the magnet  71  does not generate a sufficient displacement when it moves upward. 
         [0038]    Accordingly, if the processed parts  212  and  312  according to the present embodiment are configured, when the magnet  71  moves up/down, the magnetic flux density of the magnet  71  and the extension parts  21  and  31  is reduced, thereby being capable of increasing the magnetic flux of the coil  4  and the magnet  71 . Accordingly, a structure design for generating a strong vibration power is made possible because the magnet  71  can actively move up/down. 
         [0039]    Furthermore, one or more processed parts  211  and  311  may be disposed in a circumferential direction along the lateral surfaces of the center extension parts  21  and  31 . 
         [0040]      FIG. 4  is an enlarged view of a cross-section of the center extension parts of the casing and the bracket and the coil coupled, to the center extension parts according to an embodiment of the present invention. 
         [0041]      FIG. 4  shows a linear vibration motor  1  in which the end parts  212  and  312  of the casing center extension part  21  and the bracket center extension part  31  come into contact with each other or have a gap  8  of 0.2 mm or less. 
         [0042]    Such an embodiment is described in detail below. The center extension parts  21  and  31  that surround the inside of the coil  4  play the role of a yoke, and correspond to parts which increase the intensity of an electromagnet. 
         [0043]    Accordingly, if a gap is present, between the center extension parts  21  and  31 , it is difficult to secure a sufficient vibration power because an electromagnetic force is reduced that much. 
         [0044]    As shown in  FIG. 5 , if the center extension parts  21  and  31  are configured to be overlapped, an electromagnetic force can be further improved because an effect in that the thickness of the yoke is increased is obtained. 
         [0045]      FIG. 6  is a cross-sectional view of a linear vibration motor including the center extension parts of the casing and the bracket according to an embodiment of the present invention. 
         [0046]    Referring to  FIG. 6 , the elastic body  5  does not need to be essentially attached to one surface on the inside of the casing  2 , but may be disposed on one surface on the top of the bracket  3 , if necessary. 
         [0047]    Additionally, the structure of the aforementioned vibrator and the magnet are described in detail below. 
         [0048]    The vibrator  7  may include the magnet  71  of a ring shape, a weight body  72  of a ring shape coupled to the lateral surface of the magnet, an upper yoke  73  provided on the top of the magnet, and a lower yoke  74  provided on the bottom of the magnet. 
         [0049]    Specifically, the weight body  72  functions to help the addition of a vibration power according to the up/down movement of the vibrator  7 . The yokes  73  and  74  provided on the top and bottom of the magnet  71  function to increase an electromagnetic force. 
         [0050]    In this case, the magnet  71  may include one magnet or have a structure in which an upper magnet  711  and a lower magnet  712  are coupled. 
         [0051]    The reason for this is that when the two or more magnets  711  and  712  are added, a stronger electromagnetic force can be generated. 
         [0052]    The vibrator  7  may further include a central yoke  75  provided between the upper magnet  711  and the lower magnet  712 . 
         [0053]      FIG. 7  is a cross-sectional view of a linear vibration motor including the center extension parts of a casing and a bracket according to an embodiment of the present invention. 
         [0054]    The present embodiment corresponds to a case where the coil  4  and the magnet  71  are disposed if the magnet  71  has, a sufficient magnetism or the coil  4  has a sufficient electromagnetic force. 
         [0055]    The coil  4  may be spaced apart from the magnet  71  in the up/down direction of the magnet  71 . The magnet  71  may be changed from a structure including two or more magnets to a structure including one magnet. 
         [0056]    Accordingly, a problem in that a vibration characteristic is deteriorated due to the excessive magnetism of the magnet  71  or the excessive electromagnetic force of the coil  4  can be solved. 
         [0057]    The linear vibration motor according to an embodiment of the present invention can be easily fabricated in such a way as to be inward pressed in using a press or deep drawing method and can fix the coil through a stable structure. 
         [0058]    Furthermore, performance can be satisfied by realizing a reduction of a production cost and a working process and price competitiveness can be secured. 
         [0059]    While some exemplary embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may change and modify the present invention in various ways without departing from the essential characteristic of the present invention. Accordingly, the disclosed embodiments should not be construed as limiting the technological spirit of the present invention, but should be construed as illustrating the technological spirit of the present invention. The scope of the technological spirit of the present invention is not restricted by the embodiments, and the range of protection of the present invention should be interpreted based on the following appended claims. Accordingly, the present invention should be construed as covering all modifications or variations derived from the meaning and scope of the appended claims and their equivalents.