Electromagnetic patch type buzzer

Abstract

The invention relates to the technical field of buzzers, in particular to an electromagnetic patch type buzzer, which comprises a PCB (Printed Circuit Board) bottom plate, a power supply module and a power supply module, one end of the plastic magnetic support is connected with the PCB bottom plate, a first fixing cavity is formed in the face, facing the PCB bottom plate, of the plastic magnetic support, and a second fixing cavity communicated with the first fixing cavity is formed in the face, away from the PCB bottom plate, of the plastic magnetic support; the iron core structure is fixed in the first fixing cavity; the magnet exciting coil is arranged on the iron core structure in a sleeving manner; the diaphragm structure is fixed in the second fixed cavity, and the diaphragm structure vibrates under the action of magnetic attraction; the upper cover is fixedly connected with one end, far away from the PCB bottom plate, of the plastic magnetic support, and a vibration space of a diaphragm structure is formed between the upper cover and the second fixing cavity; wherein the magnet exciting coil is electrically connected with the conductive welding sheet, and the plastic magnetic support has magnetism and is superposed with a magnetic field generated by electrifying the magnet exciting coil so as to drive the diaphragm structure to vibrate and produce sound. By means of the structural arrangement, parts are saved, installation steps are simplified, and product cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of buzzers, and in particular to an electromagnetic patch type buzzer. Background Art

[0002] Buzzers can be divided into electromagnetic buzzers and piezoelectric buzzers based on their sound-generating principles. The principle of the electromagnetic buzzer is that the internal electromagnetic coil generates an alternating magnetic field when energized. This magnetic field forms a magnetic circuit with the permanent magnet, which produces periodic attraction on the diaphragm, thereby driving the diaphragm to vibrate and make sound; the piezoelectric buzzer uses the mechanical deformation generated by the piezoelectric sheet when energized to drive the vibration of the diaphragm to make sound; compared with piezoelectric buzzers, electromagnetic buzzers have higher driving sound pressure levels, faster response, lower costs, and more mature technology, and are still the mainstream buzzers on the market.

[0003] In the prior art, the Chinese utility model patent with authorization announcement number CN216817806U disclosed on June 24, 2022 a buzzer with rear cavity sound, which includes a shell, a base plate, pins injection-molded and embedded in the base plate, and a sound-producing component. The sound-producing component includes an iron core, a coil, a magnetic ring and a vibrating plate. The iron core is installed on the base plate, the magnetic ring is fixed on the iron core, and the coil is mounted on the iron core and electrically connected to the pin. Through such an arrangement, after the pin is energized, the coil generates electromagnetic attraction to suck down the vibrating plate, and the vibrating plate bounces back after the power is cut off. The vibration of the vibrating plate is achieved by controlling the on and off of the current to produce sound.

[0004] However, the structure of the above buzzer is relatively complex. How to reduce the cost of the product while meeting the performance and size of the product has become a problem that needs to be solved urgently. Summary of the Invention

[0005] In view of at least one of the above technical problems, the present invention provides an electromagnetic patch type buzzer, which adopts structural improvement to reduce the size and cost of the buzzer.

[0006] According to a first aspect of the present invention, there is provided an electromagnetic patch buzzer, comprising: A PCB bottom plate, wherein the PCB bottom plate has a conductive pad; A plastic magnetic bracket, one end of which is connected to the PCB base plate, the plastic magnetic bracket having a first fixing cavity on a surface facing the PCB base plate, and a second fixing cavity open to the first fixing cavity on a surface of the plastic magnetic bracket away from the PCB base plate; an iron core structure, fixed in the first fixing cavity; An excitation coil is sleeved on the iron core structure; a diaphragm structure fixed in the second fixed cavity, wherein the diaphragm structure vibrates under the action of magnetic attraction; An upper cover is fixedly connected to an end of the plastic magnetic bracket away from the PCB bottom plate, and a vibration space of the diaphragm structure is formed between the upper cover and the second fixed cavity; The excitation coil is electrically connected to the conductive welding sheet, the plastic magnetic bracket has magnetism, and is superimposed with the magnetic field generated by the excitation coil when it is energized to drive the diaphragm structure to vibrate and produce sound.

[0007] Furthermore, the soldering pads are arranged on both the front and back sides of the PCB base plate, one side is used to connect with the lead of the excitation coil, and the other side is used to connect with the external drive circuit.

[0008] Furthermore, the core structure includes a positioning plate and an iron core column arranged perpendicular to the positioning plate. A clearance groove is opened on the positioning plate, and the clearance groove corresponds to the position of the soldering pad on the PCB bottom plate for connecting to the lead of the excitation coil.

[0009] Furthermore, the first fixed cavity, the first step cavity and the connecting cavity opened with the first step cavity, the height of the first step cavity is adapted to the thickness of the positioning plate, and is used for positioning and pressing the positioning plate, and the iron core column extends into the connecting cavity.

[0010] Furthermore, the diameter of the communicating cavity is smaller than the diameter of the first step cavity, and the excitation coil is sleeved on the iron core column and is located in the communicating cavity.

[0011] Furthermore, the second fixed cavity includes a second step cavity and a third step cavity communicating with the second step cavity, the third step cavity is communicated with the communicating cavity, and the diaphragm structure is fixed on the second step cavity.

[0012] Furthermore, the diaphragm structure includes a diaphragm and a mass block fixed at the center of the diaphragm, and the mass block is fixed at a side away from the iron core column.

[0013] Furthermore, the bottom of the upper cover has a protruding positioning ring, and the outer wall of the positioning ring is adapted to the inner wall of the second step cavity.

[0014] Furthermore, the bottom of the upper cover also has a fourth step cavity, the inner diameter of the fourth step cavity is larger than the outer diameter of the mass block, so as to provide a vibration space for the mass block.

[0015] Furthermore, the bottom of the upper cover also has a raised adhesive post, which is located on the outside of the positioning ring. The plastic magnetic bracket has an adhesive groove corresponding to the adhesive post, and the adhesive groove is open to the outer wall of the plastic magnetic bracket to avoid contamination of the diaphragm by volatilization of glue.

[0016] The beneficial effects of the present invention are as follows: the present invention directly connects to the excitation coil through the PCB base plate, replacing the conventional base plate injection molded insert pin structure, and through the setting of the first fixed cavity and the second fixed cavity on the plastic magnetic bracket, the cooperation with the PCB base plate and the upper cover realizes the function of the shell, saving the use of the shell in the prior art, and the magnetic setting of the plastic magnetic bracket also replaces the magnetic ring in the prior art, saving the space occupied by the magnetic ring, thereby reducing the cost while reducing the product size. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the explosion decomposition structure of the electromagnetic patch type buzzer in an embodiment of the present invention; Figure 2 Schematic diagram of the explosion decomposition structure of the electromagnetic patch type buzzer in an embodiment of the present invention; Figure 3 Schematic diagram of the cross-sectional structure of the electromagnetic patch type buzzer in an embodiment of the present invention; Figure 4 Schematic diagram of the connection structure of the PCB base plate, the iron core structure and the excitation coil in an embodiment of the present invention; Figure 5 Schematic diagram of the connection structure of the PCB base plate, the iron core structure, the excitation coil and the plastic magnetic bracket in an embodiment of the present invention; Figure 6 In the embodiment of the present invention Figure 5 AA cross-sectional structural diagram in FIG; Figure 7 Schematic diagram of the cross-sectional structure of the connection between the plastic magnetic bracket, the diaphragm structure and the upper cover in an embodiment of the present invention; Figure 8 Schematic diagram of the exploded structure of the plastic magnetic bracket and the upper cover in an embodiment of the present invention.

[0019] Explanation of the accompanying drawings: 1. PCB base plate; 11. Solder pad; 2. Plastic magnetic bracket; 21. First fixed cavity; 211. First step cavity; 212. Connecting cavity; 22. Second fixed cavity; 221. Second step cavity; 222. Third step cavity; 23. Adhesive groove; 3. Iron core structure; 31. Positioning plate; 311. Give way groove; 32. Iron core column; 4. Excitation coil; 5. Diaphragm structure; 51. Vibrating membrane; 52. Mass block; 6. Upper cover; 61. Positioning ring; 62. Fourth step cavity; 63. Adhesive column. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] like Figures 1 to 8 The electromagnetic patch buzzer shown includes a PCB base plate 1, a plastic magnetic bracket 2, an iron core structure 3, an excitation coil 4, a diaphragm structure 5 and an upper cover 6. In some embodiments of the present invention, specifically as shown in FIG. Figures 1 to 3 As shown in the figure, the PCB base plate 1 has conductive pads 11. In the embodiment of the present invention, the PCB base plate 1 uses glass fiber reinforced epoxy resin as the substrate, and pads 11 are designed on both sides of the substrate to serve as an interface with the customer circuit and to realize the electrical power supply and control of the buzzer. During the specific soldering process, the pins of the buzzer pad 11 are connected to the customer's PBCA pad 11 through a reflow soldering process to ensure that the component is fixed in the specified position. In addition, in the embodiment of the present invention, the pads 11 are made of copper. The thermal conductivity of the substrate and copper helps to disperse the heat generated by the components after soldering, preventing local overheating and performance degradation. In addition, the glass fiber reinforced resin has high temperature tolerance and high strength, which can withstand the mechanical stress and temperature changes during the soldering process.

[0024] One end of the plastic magnetic bracket 2 is connected to the PCB base plate 1, and the plastic magnetic bracket 2 has a first fixed cavity 21 on the surface facing the PCB base plate 1, and a second fixed cavity 22 opened to the first fixed cavity 21 is provided on the surface of the plastic magnetic bracket 2 away from the PCB base plate 1; in an embodiment of the present invention, the first fixed cavity 21 is used to fix the iron core structure 3, and the second fixed cavity 22 is used to fix the diaphragm structure 5. Through the setting of this structure, structural partitioning is achieved, and the plastic magnetic bracket 2 and the upper cover 6 form a sound cavity, which realizes the sound of the diaphragm structure 5 and also helps to enhance the resonance of sound waves. In an embodiment of the present invention, a sound transmission hole is provided on the top of the upper cover 6.

[0025] The iron core structure 3 is fixed in the first fixed cavity 21, and the excitation coil 4 is sleeved on the iron core structure 3. Here, the excitation coil 4 can be sleeved on the iron core structure 3 by using enameled wire through an automatic winding machine. The enameled wire is wound on the iron core structure 3. Through the setting of the iron core structure 3, the magnetic field energy excited by the excitation coil 4 can be enhanced, thereby driving the vibration of the diaphragm structure 5.

[0026] The diaphragm structure 5 is fixed in the second fixed cavity 22. The diaphragm structure 5 vibrates under the action of magnetic attraction. In an embodiment of the present invention, the diaphragm structure 5 is made of ferromagnetic material, specifically nickel alloy. When the excitation coil 4 generates magnetism, the diaphragm structure 5 is adsorbed and bent downward. When the excitation coil 4 is powered off, the diaphragm structure 5 returns to its original shape. This reciprocating process realizes the vibration of the diaphragm structure 5, thereby achieving sound generation.

[0027] The upper cover 6 is fixedly connected to one end of the plastic magnetic bracket 2 away from the PCB base plate 1, and a vibration space of the diaphragm structure 5 is formed between the upper cover 6 and the second fixed cavity 22; in an embodiment of the present invention, the PCB base plate 1 is connected to the bottom of the plastic magnetic bracket 2, and the upper cover 6 is connected to the top of the plastic magnetic bracket 2, and the three constitute the outer shell structure of the buzzer.

[0028] In an embodiment of the present invention, the excitation coil 4 is electrically connected to the conductive soldering pad, and the plastic magnetic bracket 2 possesses magnetic properties. The magnetic field generated by the excitation coil 4 is superimposed on the magnetic field to drive the diaphragm structure 5 to vibrate and produce sound. In the embodiment of the present invention, the electromagnetic energy generated by the current is actually very small, making it difficult to drive the diaphragm structure 5 to operate normally. This is why magnetic steel is used in the prior art. In the embodiment of the present invention, the innovation of the plastic magnetic bracket 2 is not only reflected in its role as a support structure that cooperates with the PCB base plate 1 to secure the core structure 3 and diaphragm structure 5, but also in its magnetic properties that enable it to participate in the formation of the magnetic circuit, thereby superimposing the electromagnetic energy generated by the excitation coil 4 and the magnetic energy of the plastic magnetic bracket 2. This increases the magnetic attraction on the diaphragm structure 5, forcing the diaphragm structure 5 to vibrate and displace, compressing the air and producing sound. The provision of the plastic magnetic bracket 2 replaces the traditional independent permanent magnet, reducing the number of components and simplifying the structure. The overall product can also be made lighter, thinner, and more compact, and the assembly steps and material costs are reduced, thereby reducing manufacturing costs.

[0029] In the above embodiment, the PCB base plate 1 is directly connected to the excitation coil 4, replacing the conventional base plate injection-molded insert pin structure, and the first fixed cavity 21 and the second fixed cavity 22 are set on the plastic magnetic bracket 2, and the PCB base plate 1 and the upper cover 6 cooperate to realize the role of the shell, saving the use of the shell in the prior art, and the magnetic setting of the plastic magnetic bracket 2 also replaces the magnetic ring in the prior art, saving the space occupied by the magnetic ring, thereby reducing the cost while reducing the product size.

[0030] Based on the above examples, please continue to refer to Figure 1 and Figure 2 In the embodiment of the present invention, solder pads 11 are provided on both sides of the PCB base plate 1. One side is used to connect to the leads of the excitation coil 4, and the other side is used to connect to the external drive circuit. The design of the double-sided solder pad 11 enables bidirectional internal and external connections. On the one hand, it is used to connect to the external drive circuit or main control chip. Through the arrangement of this structural form, the space resources of the PCB base plate 1 can be fully utilized, the integration level can be improved, and the signal path can be shortened and more stable.

[0031] In an embodiment of the present invention, Figure 4 As shown in , the core structure 3 includes a positioning plate 31 and a core column 32 arranged perpendicular to the positioning plate 31. The positioning plate 31 is provided with a clearance groove 311. The clearance groove 311 corresponds to the position of the pad 11 on the PCB base plate 1 for connecting the lead of the excitation coil 4. The provision of the clearance groove 311 shortens the path when the lead of the excitation coil 4 connects to the pad 11 on the PCB base plate 1, which also helps reduce the overall weight, thereby improving the reliability of the connection and further achieving lightweight products.

[0032] For the internal structure of the plastic magnetic bracket 2, please continue to refer to Figure 5 and Figure 6 , the first fixed cavity 21, the first step cavity 211 and the connecting cavity 212 opened with the first step cavity 211, the height of the first step cavity 211 is adapted to the thickness of the positioning plate 31, which is used for positioning and pressing the positioning plate 31, and the core column 32 extends into the connecting cavity 212. It should be pointed out here that in the embodiment of the present invention, although a clearance groove 311 is provided on the positioning plate 31, the overall external contour of the positioning plate 31 is adapted to the inner wall of the first fixed cavity 21 to achieve the fixation of the positioning plate 31, and by extending the core column 32 into the connecting cavity 212, a deep magnetic flux path is formed, which is conducive to improving the magnetic flux density and concentration. This kind of ladder + embedded structure not only improves the stability of the structure, but also facilitates the control of assembly errors.

[0033] Furthermore, the diameter of the connecting cavity 212 is smaller than the diameter of the first stepped cavity 211, and the excitation coil 4 is sleeved on the core column 32 and located within the connecting cavity 212. The provision of the small-diameter connecting cavity 212 can limit the installation area of ​​the excitation coil 4, achieve precise spatial positioning, and enable the magnetic flux to be concentrated below the diaphragm structure 5, thereby improving the efficiency of sound generation.

[0034] Please continue to refer to Figure 7 In this embodiment of the present invention, the second fixed cavity 22 includes a second stepped cavity 221 and a third stepped cavity 222 communicating with the second stepped cavity 221. The third stepped cavity 222 communicates with the communicating cavity 212, and the diaphragm structure 5 is fixed to the second stepped cavity 221. This structural design allows the diaphragm to vibrate freely up and down while ensuring that the diaphragm is fixed and stable without displacement. The coordination of multiple cavities ensures sufficient sound wave transmission, enhances the resonance effect, and improves the sound intensity.

[0035] In an embodiment of the present invention, the diaphragm structure 5 includes a diaphragm 51 and a mass block 52 fixed to the center of the diaphragm 51. The mass block 52 is fixed to the side away from the iron core 32. By adding the mass block 52 to the diaphragm 51, the resonant frequency can be adjusted, the low-frequency response can be enhanced, and the sound quality and penetration can be improved. By placing the mass block 52 on the side away from the iron core 32, the problem of center attraction caused by magnetic attraction can be avoided.

[0036] Please continue to refer to Figure 7 and Figure 2In an embodiment of the present invention, to further improve the positioning accuracy of the upper cover 6, a positioning ring 61 is provided on the bottom of the upper cover 6. The outer wall of the positioning ring 61 is adapted to fit within the inner wall of the second stepped cavity 221. The positioning ring 61 prevents the upper cover 6 from becoming dislocated or loose. Furthermore, this structure provides a hard edge to the diaphragm's vibration space, improving the stability and focus of the resonant sound field.

[0037] Please continue to refer to Figure 7 In this embodiment of the present invention, the bottom of the upper cover 6 further comprises a fourth stepped cavity 62. The inner diameter of the fourth stepped cavity 62 is larger than the outer diameter of the mass 52, providing a vibration space for the mass 52. The provision of the fourth stepped cavity 62 prevents mechanical interference between the upper cover 6 and the mass 52 during vibration, ensuring stable sound output.

[0038] like Figure 8 As shown in FIG, in an embodiment of the present invention, in order to prevent the diaphragm structure 5 from being contaminated by the glue due to squeezing or volatilization when the upper cover 6 and the plastic magnetic bracket 2 are connected using glue, the bottom of the upper cover 6 is further provided with a protruding adhesive post 63, which is located outside the positioning ring 61, and the plastic magnetic bracket 2 is provided with an adhesive groove 23 corresponding to the adhesive post 63. The adhesive groove 23 is open to the outer wall of the plastic magnetic bracket 2 to prevent the diaphragm 51 from being contaminated by the volatilization of the glue. Figure 8 As shown in the figure, by setting the bonding groove 23 to be open to the outer wall of the plastic magnetic bracket 2, when gluing, glue is poured on the bottom surface of the bonding groove 23, and then the bonding column 63 on the upper cover 6 is fitted with the bonding groove 23 on the plastic magnetic bracket 2, and then cured by high-temperature baking. By setting the bonding column 63 and the bonding groove 23, in conjunction with the setting of the positioning ring 61, it is possible to avoid contamination of the diaphragm by volatilization of glue, thereby improving the yield rate of the product.

[0039] During construction, the excitation coil 4 is first wound around the core column 32 using an automatic winding machine. An appropriate amount of epoxy glue is then applied to the center of the PCB baseboard 1. The core is then bonded to the PCB baseboard 1 and cured by high-temperature baking. The leads of the excitation coil 4 are then soldered to the pads 11 of the PCB board and tested for conductivity. Epoxy resin glue is then applied to the first step cavity 211 and bottom surface of the plastic magnet support 2, and the assembly is completed with the PCB baseboard 1. After high-temperature baking and curing, the diaphragm is placed on the second step cavity 221 of the plastic magnet support 2. A small amount of high-temperature glue is then injected into the bonding groove 23 of the plastic magnet support 2. The bonding column 63 on the upper cover 6 is bonded to the bonding groove 23, and the glue is cured by high-temperature baking. The finished product is assembled. With this structure, the upper cover 6 and the plastic magnet support 2 are secured solely via the bonding groove 23, significantly reducing the risk of diaphragm contamination and improving product reliability. Furthermore, the omission of components (magnetic ring and housing) simplifies the installation process and reduces product cost.

[0040] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An electromagnetic patch buzzer, characterized in that: include: A PCB base plate, wherein the PCB base plate has a conductive pad; A plastic magnetic bracket, one end of which is connected to the PCB base plate, the plastic magnetic bracket having a first fixing cavity on a surface facing the PCB base plate, and a second fixing cavity open to the first fixing cavity on a surface of the plastic magnetic bracket away from the PCB base plate; an iron core structure, fixed in the first fixing cavity; An excitation coil is sleeved on the iron core structure; a diaphragm structure fixed in the second fixed cavity, wherein the diaphragm structure vibrates under the action of magnetic attraction; An upper cover is fixedly connected to an end of the plastic magnetic bracket away from the PCB bottom plate, and a vibration space of the diaphragm structure is formed between the upper cover and the second fixed cavity; The excitation coil is electrically connected to the conductive welding sheet, the plastic magnetic bracket has magnetism, and is superimposed with the magnetic field generated by the excitation coil when it is energized to drive the diaphragm structure to vibrate and produce sound.

2. The electromagnetic patch buzzer according to claim 1, characterized in that: The soldering pads are arranged on both the front and back sides of the PCB bottom plate, one side of which is used to be connected to the lead of the excitation coil, and the other side is used to be connected to the external drive circuit.

3. The electromagnetic patch buzzer according to claim 2, characterized in that: The iron core structure includes a positioning plate and an iron core column arranged perpendicular to the positioning plate. A clearance groove is opened on the positioning plate, and the clearance groove corresponds to the position of the soldering pad on the PCB bottom plate for connecting to the lead of the excitation coil.

4. The electromagnetic patch buzzer according to claim 3, characterized in that: The first fixed cavity, the first step cavity and the connecting cavity opened with the first step cavity, the height of the first step cavity is adapted to the thickness of the positioning plate, and is used for positioning and pressing the positioning plate, and the iron core column extends into the connecting cavity.

5. The electromagnetic patch buzzer according to claim 4, characterized in that: The diameter of the communicating cavity is smaller than the diameter of the first step cavity. The excitation coil is sleeved on the iron core column and is located in the communicating cavity.

6. The electromagnetic patch buzzer according to claim 5, characterized in that: The second fixed cavity includes a second step cavity and a third step cavity communicating with the second step cavity, the third step cavity is communicated with the communicating cavity, and the diaphragm structure is fixed on the second step cavity.

7. The electromagnetic patch buzzer according to claim 6, characterized in that: The diaphragm structure includes a diaphragm and a mass block fixed at the center of the diaphragm, and the mass block is fixed at a side away from the iron core column.

8. The electromagnetic patch buzzer according to claim 7, characterized in that: The bottom of the upper cover is provided with a protruding positioning ring, and the outer wall of the positioning ring is adapted to the inner wall of the second step cavity.

9. The electromagnetic patch buzzer according to claim 8, characterized in that: The bottom of the upper cover further has a fourth step cavity, the inner diameter of which is larger than the outer diameter of the mass block, so as to provide a vibration space for the mass block.

10. The electromagnetic patch buzzer according to claim 8, characterized in that: The bottom of the upper cover also has a raised adhesive post, which is located on the outside of the positioning ring. The plastic magnetic bracket has an adhesive groove corresponding to the adhesive post, and the adhesive groove is open to the outer wall of the plastic magnetic bracket to avoid contamination of the diaphragm by volatilization of glue.

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