Patent Publication Number: US-2011062799-A1

Title: Stator assembling mechanism of linear motor that is adapted to automated assembling process

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a driving technique, and more particularly to a stator assembling mechanism of linear motor that is adapted to automated assembling process. 
       FIGS. 1 and 2  show a conventional linear motor stator structure  1 . The linear motor stator structure  1  includes a threaded rod  3  and multiple magnetic rings  2  coaxially fitted on the threaded rod  3  to repel each other. Two threaded retaining collars  4  are screwed on two ends of the threaded rod  3  to tighten and locate the magnetic rings  2  on the threaded rod  3 . Then an outer sleeve  5  is coaxially fitted around the magnetic rings  2  and two end caps  6  are plugged into two ends of the outer sleeve  5  to bind the magnetic rings  2  together so as to form the stator of the linear motor. 
     The conventional linear motor stator structure is composed of numerous components. When assembled, the magnetic rings  2  must be first fixed on the threaded rod  3  and then the end caps  6  and outer sleeve  5  are connected to enclose the magnetic rings  2  and threaded rod  3 . Accordingly, the assembling process includes at least two steps, which cannot be completed by the same processing machine. Moreover, conventionally, in the first assembling step, the magnetic rings  2  are assembled with the threaded rod  3  artificially. The magnetic rings are arranged with the magnetic poles of the same polarity adjacent to each other. It costs much labor to overcome the strong repelling force between the adjacent magnetic rings. Therefore, the production efficiency can be hardly promoted. Also, after the first processing step is completed, the end caps  6  and the outer sleeve  5  must be further connected to bind the magnetic rings together in the second processing step. The second processing step can be completed under the assistance of a mechanical apparatus. However, due to the low efficiency of the first processing step, the assembling process still cannot be completed efficiently. 
     SUMMARY OF THE INVENTION 
     It is therefore a primary object of the present invention to provide a stator assembling mechanism of linear motor that is adapted to automated assembling process. With the linear motor stator assembling mechanism, the linear motor stator can be assembled by one single process so that the manufacturing cost is lowered. 
     It is a further object of the present invention to provide the above stator assembling mechanism of linear motor, which makes it easier to assemble the linear motor state and makes it possible to automate the assembling process of the linear motor stator. Therefore, the production efficiency of the linear motor stator can be enhanced. 
     To achieve the above and other objects, the stator assembling mechanism of linear motor that is adapted to automated assembling process of the present invention includes a sleeve, several magnetic members and two end pieces. The sleeve includes a straight tubular body having two axial ends each having an opening. The magnetic members are sequentially axially arranged in the straight tubular body with the magnetic poles of the same polarity adjacent to each other. Each end piece has a main body formed with a threaded section for screw-connecting with one axial end of the straight tubular body so as to block the openings thereof and restrict the magnetic members within the sleeve. A driven section is disposed at one end of the main body. Via the driven section, an external power device can drive the main body to screw-connect the threaded section with the axial end of the straight tubular body so as to connect the end piece with the sleeve. 
     The present invention can be best understood through the following description and accompanying drawings wherein: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective exploded view of a conventional linear motor stator structure; 
         FIG. 2  is a sectional view of the conventional linear motor stator structure; 
         FIG. 3  is a perspective exploded view of a first embodiment of the present invention; 
         FIG. 4  is a perspective assembled view of the first embodiment of the present invention; 
         FIG. 5  is a perspective view of the end piece of the first embodiment of the present invention; 
         FIG. 6  is a sectional view of a part of the first embodiment of the present invention; 
         FIG. 7  is a perspective view showing the assembling process of the first embodiment of the present invention; and 
         FIG. 8  is a perspective view showing different end pieces of other embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 3 to 7 . According to a first embodiment, the stator assembling mechanism  10  of linear motor that is adapted to automated assembling process of the present invention includes a sleeve  20 , multiple magnetic members  30  and two end pieces  40 . 
     The sleeve  20  includes a straight tubular body  21  with a certain length. The straight tubular body  21  has two axial ends each having an opening  22  in communication with internal space of the straight tubular body  21  and outer side thereof. Two inner threads  23  are respectively annularly formed on wall faces of the openings  22  of two ends of the straight tubular body  21 . 
     The magnetic members  30  are sequentially serially arranged and received in the internal space of the straight tubular body  21  along an axis thereof with the magnetic poles of the same polarity adjacent to each other. Each magnetic member  30  includes three magnetic bodies  31 , which are serially arranged with the magnetic poles of different polarities adjacent to each other to attract each other. 
     Each end piece  40  has a columnar main body  41 . The main body  41  has a first section  411  directed to a first axial end of the main body  41  and a second section  412  directed to a second axial end of the main body  41 . The first section  411  has an outer diameter approximately equal to inner diameter of the straight tubular body  21 , whereby the first section  411  can be coaxially plugged into the opening  22  of the straight tubular body  21  by a certain depth. An outer thread is annularly disposed on a circumference of the second section  412  of the main body  41  to form a threaded section  42 . The threaded section  42  is spaced from the first axial end of the main body  41 . A regular hexagonal socket is disposed on an end face of the second axial end of the main body to form a driven section  43  in adjacency to the threaded section  42 . 
     Please refer to  FIG. 7 . The stator assembling mechanism  10  of linear motor of the present invention is adapted to automated assembling process. To speak more specifically, the sleeve  20  provides a receiving space for the magnetic members  30 . The straight tubular body  21  serves to restrict the magnetic members  30  in the internal space and keep the magnetic members  30  coaxially serially arranged and located in contact with each other. In practical assembling process, a conventional power-driven tool such as a power screwdriver  50  with a hexagonal screwdriver bit  51  can be inserted into the driven section  43  of the end piece  40  to drive and rotate the main body  41 . In this case, the threaded section  42  can be easily screw-connected with the corresponding inner thread  23  to block the opening  22 . At the same time, the magnetic members  30  are sealed in the internal space of the straight tubular body  21 . Accordingly, the assembling process of the linear motor stator can be automated. 
     In comparison with the prior art, the linear motor stator assembling mechanism  10  of the present invention has smaller number of components and smaller number of varieties of components. This can reduce material cost and stock cost. More importantly, the linear motor stator assembling mechanism  10  of the present invention is adapted to automated assembling process. The sleeve  20  and the end pieces  40  can be connected and assembled with each other by means of external power tool in single assembling process. Therefore, the linear motor stator can be more conveniently assembled at higher efficiency than the prior art. Accordingly, the production efficiency can be greatly enhanced to lower manufacturing cost and increase competitive ability of the products. 
     The above embodiment is only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention as follows:
         1. The threaded section can be alternatively formed of an inner thread. In this case, outer threads are annularly formed on outer circumferences of two axial ends of the straight tubular body corresponding to the inner thread for screw-connecting therewith.   2. The driven section of the end piece is not limited to the hexagonal socket. Alternatively, the driven section can have any other regular polygonal shape. For example, as shown in  FIG. 8 , the driven section can be a pentagonal socket  43   a,  a quadrangular socket  43   b,  a triangular socket  43   c,  a straight slot  43   d,  a cross slot  43   e  or multiple symmetrical circular holes  43   f,    43   g.  All these configurations are included in the scope of the present invention.   3. The driven section of the end piece can be alternatively a polygonal block integrally formed at the end of the main body. In this case, a drive tool such as a socket wrench can be fitted on the polygonal block to drive the end piece. The polygonal block can have a shape identical to that of any of the aforesaid sockets. That is, the polygonal block can be a regular polygonal block such as a hexagonal block, a quadrangular block, etc.       

     In other words, the stator assembling mechanism of linear motor that is adapted to automated assembling process of the present invention is characterized in that via a force application section, (that is, the driven section), an external power device can drive the main body to assemble the end piece with the sleeve and form the linear motor stator by one single step. All those modifications of the above embodiments should be included in the scope of the present invention.