Abstract:
A moving iron sounding device includes a casing, a diaphragm sounding system, and a magnetic circuit system. The magnetic circuit system includes a dual-rectangle-shaped magnetic circuit, an inductance coil, and an armature. The diaphragm sounding system includes a support ring and a composite diaphragm. The composite diaphragm includes a diaphragm sheet and a metal sheet. One end of the metal sheet is welded to the vibration portion through a connecting arm, and another end of the metal sheet is connected to the support ring. The present invention achieves a stable connection of the diaphragm sounding system and the magnetic circuit system and ensures the quality of the product. During the process of assembly, the adhesive won&#39;t be spilled on the diaphragm.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sounding device used for speakers, loudspeakers, headphones, and the like, and more particularly, to a moving iron sounding device. 
     2. Description of the Prior Art 
     A moving iron sounding device is widely used to speakers, loudspeakers, headphones, and the like. The moving iron sounding device comprises a casing, a diaphragm sounding system, and a magnetic circuit system. The diaphragm sounding system comprises a vibration plate, a resin diaphragm, and a retaining frame. When assembled, the vibration plate is adhered to the bottom of the resin diaphragm, and then the circumferential edge of the resin diaphragm is adhered to the upper surface of the retaining frame to cover the opening of the retaining frame. Because there is a gap between the vibration plate and the inner wall surface of the opening of the retaining frame, the gap is filled with the adhesive for connecting the vibration plate with the retaining frame. When the vibration plate and the resin diaphragm are adhered to the retaining frame, it is not easy to get a precise alignment. When the gap is filled with the adhesive, the adhesive may spill on the reign diaphragm. These factors may impact the quality of the products. 
     In general, the diaphragm sounding system and the magnetic circuit system are connected by a guide wire. When assembled, one end of the guide wire is welded to a free end of an elastic plate of the magnetic circuit system, and another end of the guide wire is welded or adhered to the diaphragm of the diaphragm sounding system. The assembly is troublesome, and the production efficiency is lower. The connecting joints of the two ends of the guide wire may loosen to influence the functions of the products. 
     Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve this problem. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a moving iron sounding device. It is easy to achieve a stable connection of a diaphragm sounding system and a magnetic circuit system, and it is convenient to align a composite diaphragm with a support ring so as to be bound together. The adhesive won&#39;t be spilled on the diaphragm so as to ensure the quality of the products. 
     In order to achieve the aforesaid object, the moving iron sounding device of the present invention comprises a casing, a diaphragm sounding system, and a magnetic circuit system. The diaphragm sounding system and the magnetic circuit system are located in the casing. The magnetic circuit system comprises a dual-rectangle-shaped magnetic circuit, an inductance coil, and an armature. The armature has a vibration portion. The vibration portion passes through the inductance coil. A free end of the vibration portion is suspended in the dual-rectangle-shaped magnetic circuit. The diaphragm sounding system includes a support ring and a composite diaphragm. The support ring has an opening. The composite diaphragm is disposed on top of the support ring to cover the opening of the support ring. The composite diaphragm includes a diaphragm sheet and a metal sheet which are composited to become one-piece. A first end of the metal sheet is connected with the vibration portion. An interval is defined between the first end of the metal sheet and an inner wall surface of the opening of the support ring. A second end of the metal sheet is directly attached to the support ring. The metal sheet is connected with a connecting arm. A distal end of the connecting arm is provided with a welding portion. The welding portion is welded to the free end of the vibration portion. 
     The beneficial effect of the present invention is to improve the structure of the diaphragm sounding system. The end of the metal sheet is directly attached to the support ring, such that it is convenient to align the composite diaphragm with the support ring so as to be bound together. This solves the problem of the prior art. The adhesive won&#39;t be spilled on the diaphragm to ensure the quality of the products. The metal sheet is bent to extend and form a connecting arm. The connecting arm is connected between the diaphragm sounding system and the magnetic circuit system by welding. It is not hard to process the connection, and the connection is stable. During transportation and use, the connecting joint won&#39;t loosen so as to ensure the stability of the products. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view according to a first embodiment of the present invention; 
         FIG. 2  is an exploded view according to the first embodiment of the present invention; 
         FIG. 3  is a sectional view according to the first embodiment of the present invention; 
         FIG. 4  is another sectional view according to the first embodiment of the present invention; 
         FIG. 5  to  FIG. 7  shows another three embodiments of the welding portion of  FIG. 3 ; 
         FIG. 8  is an exploded view according to a second embodiment of the present invention; 
         FIG. 9  shows another embodiment of the diaphragm sounding system of  FIG. 8 ; and 
         FIG. 10  shows another embodiment of the sound output hole of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
     As shown in  FIG. 1  through  FIG. 10 , the present invention discloses a moving iron sounding device. The moving iron sounding device comprises a casing  10 , a diaphragm sounding system  20 , and a magnetic circuit system  30 . The diaphragm sounding system  20  and the magnetic circuit system  30  are located in the casing  10 . 
       FIG. 1  through  FIG. 7  shows a first embodiment of the present invention. The casing  10  includes a main body  11  and a cover  12 . The main body  11  comprises a base and a side wall integrally connected to the base. The cover  12  is configured to cover an opening at the upper end of the main body  11 . The diaphragm sounding system  20  and the magnetic circuit system  30  are located in the main body  11 . The diaphragm sounding system  20  is located above the magnetic circuit system  30 . 
     The diaphragm sounding system  20  includes a support ring  201  and a composite diaphragm  202 . The support ring  201  has an opening. The composite diaphragm  202  is disposed on top of the support ring  201  to cover the opening of the support ring  201 . The composite diaphragm  202  includes a diaphragm sheet  21  a metal sheet  22  which are composited to become one-piece. A first end  23  of the metal sheet  22  is bent downward to extend and form a connecting arm  223 . The connecting arm  223  is connected with a vibration portion  334  of the magnetic circuit system  30 . In an embodiment, the connecting arm and the metal sheet can be designed to be separate. An interval  206  is defined between the first end  23  of the metal sheet  22  and an inner wall surface of the opening of the support ring  201 . A second end  24  of the metal sheet  22  is directly attached to the support ring  201 . In this embodiment, a distal end face of the second end  24  of the metal sheet  22  is attached to the inner wall surface of the support ring  201 . An upper surface of the second end  24  is flush with an upper surface of the support ring  201 . As shown in  FIG. 2  and  FIG. 3 , the inner wall surface of the support ring  201  is further formed with a cavity  203  for accommodating adhesive. The cavity  203  penetrates the upper and lower surfaces of the support ring  201 . The distal end face of the second end  24  of the metal sheet  22  is attached to the inner wall surface of the cavity  203 . An inner bottom portion of the cavity  203  is provided with adhesive  204 . The adhesive  204  is disposed between the bottom face of the metal sheet  22  and the inner wall surface of the cavity  203 . A circumferential edge of the diaphragm sheet  21  extends out of the second end  24  of the metal sheet  22  to be attached to the upper surface of the support ring  201 , as shown in  FIG. 3 . 
     As shown in  FIG. 4 , a welding portion  224  has a first welding face  227 . An end face of a free end of the vibration portion  334  is defined as a second welding face  335 . The first welding face  227  is attached to the second welding face  335 . As shown in  FIG. 7 , the welding portion  224  can be directly welded to the second welding face  335 . As shown in  FIG. 4  through  FIG. 6 , the welding portion  224  can be formed with a through groove  228  for welding. The through groove  228  penetrates the first welding face  227  to another opposing face of the welding portion  224 . The second welding face  335  is exposed corresponding to the through groove  228 . The through groove  228  is located at one side or two sides of the welding portion  224 . In this embodiment, the through groove  228  is formed with an opening at the side of the welding portion  224  to penetrate an outside thereof. The second welding face  335  extends toward the outside of the opening and extends out of the opposing face of the welding portion  224 . This configuration is beneficial for welding operation and ensures the stability of welding. 
     The magnetic circuit system  30  comprises a dual-rectangle-shaped magnetic circuit  31 , an inductance coil  32 , and an armature  33 . The armature  33  includes a substrate  331 , two retaining walls  333 , and a vibration portion  334 . The vibration portion  334  extends right from a right end of the substrate  331  and then is bent reversely. The free end of the vibration portion  334  extends left. Two sides of the substrate  331  are formed with side walls  332  extending upward, respectively. Left ends of the side walls  332  extend left to form the retaining walls  333 , respectively. The dual-rectangle-shaped magnetic circuit  31  is located between the two retaining walls  333 . The dual-rectangle-shaped magnetic circuit  31  includes a U-shaped iron piece  311 , an I-shaped iron piece  312 , and two magnets  313 . The I-shaped iron piece  312  is welded to an opening of an upper end of the U-shaped iron piece  312  to form a dual-rectangle-shaped configuration. The two magnets  313  are installed on the U-shaped iron piece  311  and the I-shaped iron piece  312 , respectively. The vibration portion  334  passes through the inductance coil  32 , and the free end of the vibration portion  334  is suspended in the dual-rectangle-shaped magnetic circuit  31 . 
     The working principle of the moving iron sounding device is described hereinafter. The alternating current signal is transmitted to the inductance coil  32 . The magnetic field generated by the inductance coil  32  is conducted to the vibration portion  334 , enabling the vibration portion  334  to generate magnetic polarization. Along with the change of the magnetic pole and the change of the intensity of the vibration portion  334 , the vibration portion  334  subject to the magnetic force vibrates in the space  314  defined between the two magnets  313 . The vibrational frequency is directly transmitted to the composite diaphragm  202 . By the diaphragm sheet  21 , the surrounding air is agitated to transmit the sound out through a sound output hole  121 . 
       FIG. 8  shows a second embodiment of the present invention. The second embodiment is substantially similar to the first embodiment with the exceptions described hereinafter. The design of the connecting arm is different from that of the first embodiment. The lower end of the connecting arm is further connected with an extension arm. The extension arm and the connecting arm are disposed separately. The welding portion  224  is disposed on the extension arm. 
     As shown in  FIG. 8 , the distal end face the second end  24  of the metal sheet  22  is flush with the corresponding end face of the diaphragm sheet  21 . The second end  24  of the metal sheet  22  is directly attached to the upper end face of the support ring  201 . As shown in  FIG. 8 , the metal sheet  22  comprises a dual-rectangle-shaped frame portion  221  and a vibration arm portion  222  suspended in the dual-rectangle-shaped frame portion  221 . One end of the dual-rectangle-shaped frame portion  221  is integrally formed with an inner wall surface of the dual-rectangle-shaped frame portion  221 . A raised arc portion  225  is integrally formed between the vibration arm portion  222  and the dual-rectangle-shaped frame portion  221 . Another end of the vibration arm portion  222  is suspended and connected with the vibration portion  334 . The diaphragm sheet  21  corresponds in shape to the dual-rectangle-shaped frame portion  221 . The diaphragm sheet  21  is adhered to the dual-rectangle-shaped frame portion  221 . The arc portion  225  is exposed out of the diaphragm sheet  21 . 
     As shown in  FIG. 9 , there is no arc portion  225  between the vibration arm portion  222  and the dual-rectangle-shaped frame portion  221 . The vibration arm portion  222  extends horizontally from the dual-rectangle-shaped frame portion  221 . The metal sheet  22  is provided with three reinforcement ribs thereon. The reinforcement ribs are formed by pressing. The upper surfaces of the reinforcement ribs are formed with convex portions. The lower surfaces of the reinforcement ribs are formed with corresponding concave portions. The structure as shown in  FIG. 8  and  FIG. 9  can be applied to the first embodiment. 
     To compare  FIG. 1  with  FIG. 10 , the sound output hole  121 , as shown in  FIG. 1 , is disposed on the top of the cover  12 . A sound output hole  122 , as shown in  FIG. 10 , is disposed at a side of the cover  12 , corresponding in position to the connecting arm  222 . The side is provided with a sound guide cylinder  123  toward the sound output hole  122  for guiding the sound to output. 
     Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.