Patent Publication Number: US-2011073790-A1

Title: Electromagnetic Valve

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an electronic switch, and more particularly to an electromagnetic valve. 
     2. The Related Art 
     In the automation field, electromagnetic valves are often acted as electronic switches with an automatic control function to be widely used in many automated machines and electronic products. The conventional electromagnetic valve achieves the automatic control action by means of making a slide body relatively move there and back. The relative movement of the slide body is generally achieved by means of elastic elements such as springs. However, because the space in the electromagnetic valve is small, it is difficult to mount the elastic element in the electromagnetic valve. In addition, the elastic element often has a problem of elastic fatigue, thereby reducing the effectiveness of the electromagnetic valve. Therefore, an electromagnetic valve capable of overcoming the foregoing problems is required. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an electromagnetic valve including an electromagnetic coil module, a slide body, two magnetic conductors and a permanent magnet. The electromagnetic coil module includes a coiling body and a coil coiled around the coiling body. The coiling body defines a receiving passage therein having two opposite end mouths. The electromagnetic coil module produces a magnetic field when a current flows through the coil. The slide body is moveably disposed in the receiving passage of the coiling body. The two magnetic conductors are mounted to the corresponding end mouths of the receiving passage of the coiling body respectively. The permanent magnet is embedded in the slide body with two opposite magnetic ends thereof fronting the corresponding magnetic conductors respectively. The permanent magnet under the combined actions of the magnetic attraction of the magnetic conductors and the magnetic field produced by the electromagnetic coil module drives the slide body to relatively move between the magnetic conductors so as to achieve corresponding control actions. So the electromagnetic valve has a simple structure and a relatively longer life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which: 
         FIG. 1  is an exploded perspective view of an electromagnetic valve according to a first embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of the electromagnetic valve of  FIG. 1 , wherein the electromagnetic valve is assembled and lying in one work state; 
         FIG. 3  is a cross-sectional view of the electromagnetic valve of  FIG. 1 , wherein the electromagnetic valve is assembled and lying in another work state; 
         FIG. 4  is an exploded perspective view of an electromagnetic valve according to a second embodiment of the present invention; 
         FIG. 5  is a cross-sectional view of the electromagnetic valve of  FIG. 4 , wherein the electromagnetic valve is assembled and lying in one work state; and 
         FIG. 6  is a cross-sectional view of the electromagnetic valve of  FIG. 4 , wherein the electromagnetic valve is assembled and lying in another work state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to  FIGS. 1˜3 , an electromagnetic valve  100  according to a first embodiment of the present invention includes a housing  1  made of metal material, two magnetic conductors designated as a first magnetic conductor  2  and a second magnetic conductor  3  respectively, an electromagnetic coil module  8 , a slide body  6  and a permanent magnet  7 . 
     The housing  1  has a first board  11 , a second board  12  spaced from and parallel to the first board  11 , and a pair of parallel third boards  13  perpendicularly connecting the first board  11  and the second board  12  to make the housing  1  show a rectangular hollow shape. Accordingly, a rectangular receiving chamber  14  is surrounded by the first board  11 , the second board  12  and the pair of third boards  13 . A first fixing hole  15  is opened in a center of the first board  11  and a second fixing hole  16  is opened in a center of the second board  12  to face the first fixing hole  15 . 
     The first magnetic conductor  2  and the second magnetic conductor  3  are respectively fixed in the first fixing hole  15  and the second fixing hole  16  of the housing  1 . A center of the first magnetic conductor  2  defines a columned inserting perforation  21  penetrating therethrough to communicate with the receiving chamber  14  and face the second magnetic conductor  3 . The electromagnetic coil module  8  includes a cylindrical coiling body  4  and a coil  5  coiled around the coiling body  4 . Accordingly, the coiling body  4  defines a columned receiving passage  41  penetrating therethrough and having the same axis as the coiling body  4 . Two opposite end mouths of the receiving passage  41  are respectively defined as a first end mouth  411  and a second end mouth  412 . The electromagnetic coil module  8  is mounted in the receiving chamber  14  of the housing  1  with the second end mouth  412  facing the second magnetic conductor  3  and the first end mouth  411  facing the first magnetic conductor  2  to make the inserting perforation  21  lay in line with the receiving passage  41 . 
     The slide body  6  has a columned base portion  61  and a slide rod  62  extended from a middle of one end surface of the base portion  61  and having a narrower diameter than the base portion  61 . Accordingly, an annular stopping portion  63  is formed at the junction of the base portion  61  and the slide rod  62 . The slide body  6  is slideably disposed in the receiving passage  41  of the coiling body  4  with the slide rod  62  being always inserted in the inserting perforation  21  of the first magnetic conductor  2 . The permanent magnet  7  is of substantially columned shape, and two opposite ends thereof are defined as a first magnetic end  71  and a second magnetic end  72  respectively. The permanent magnet  7  is embedded in the base portion  61  with the first magnetic end  71  fronting the first magnetic conductor  2  to form a first distance D 1  between the first magnetic end  71  and the first end mouth  411  of the coiling body  4 , and the second magnetic end  72  fronting the second magnetic conductor  3  to form a second distance D 2  between the second magnetic end  72  and the second end mouth  412  of the coiling body  4 . Furthermore, the first distance D 1  is always longer than the second distance D 2  so as to ensure the movement direction of the slide body  6  to further prevent the slide body  6  from abnormally swaying. 
     When there is current flowed through the coil  5 , a magnetic field correspondingly produced to make the permanent magnet  7  adsorbed by the first magnetic conductor  2  or the second magnetic conductor  3 . When the magnetic field has the uniform polarity to the permanent magnet  7 , the permanent magnet  7  under the combined action of the magnetic field and the magnetic attraction of the first magnetic conductor  2  drives the base portion  61  to move toward the first end mouth  411  until the stopping portion  63  is against the first magnetic conductor  2 . At this time, the slide rod  62  stretches out of the first magnetic conductor  2  through the inserting perforation  21 . When the polarity of the magnetic field is opposite to that of the permanent magnet  7 , the permanent magnet  7  under the combined action of the magnetic field and the magnetic attraction of the second magnetic conductor  3  drives the slide body  6  to move toward the second end mouth  412  until an end of the base portion  61  opposite to the slide rod  62  is against the second magnetic conductor  3 . At this time, the slide rod  62  is withdrawn back into the inserting perforation  21 . Therefore, corresponding control actions can be achieved by means of the permanent magnet  7  driving the slide body  6  to relatively move under the combined actions of the magnetic field and the magnetic attraction of the magnetic conductors  2 ,  3 . 
     Referring to  FIGS. 4˜6 , an electromagnetic valve  200  according to a second embodiment of the present invention is shown and similar to the electromagnetic valve  100  in the first embodiment. The difference therebetween is that the electromagnetic valve  200  has a slide body  6 ′ different from the slide body  6  of the electromagnetic valve  100  of the first embodiment. In the second embodiment, a base portion  61 ′ of the slide body  6 ′ has a substantially equal diameter to a slide rod  62 ′, and an annular stopping portion  63 ′ is formed by means of protruding outward from the junction of the base portion  61 ′ and the slide rod  62 ′. The electromagnetic valve  200  has the same working principle as the electromagnetic valve  100 , so it will not be described anymore. 
     As described above, the permanent magnet  7  is embedded in the slide body  6 ( 6 ′), and furthermore, the magnetic conductors  2 ,  3  are disposed to front the corresponding magnetic ends  71 ,  72  of the permanent magnet  7  respectively, so that the permanent magnet  7  under the combined actions of the magnetic attraction of the magnetic conductors  2 ,  3  and the magnetic field produced by the electromagnetic coil module  8  can drive the slide body  6 ( 6 ′) to relatively move so as to achieve the corresponding control actions. So the electromagnetic valve  100 ( 200 ) of the present invention has a simple structure and a relatively longer life.