Shell of sound production device, sound production device and electronic equipment

Abstract

The invention discloses a shell of a sound production device, the sound production device and electronic equipment. The shell comprises a first shell body and a second shell body, the first shell body and the second shell body are each provided with a welding part, the welding part of the first shell body and the welding part of the second shell body are connected in an ultrasonic welding mode, and the welding parts are formed by injection molding of polypropylene composite materials composed of carbon fibers and polypropylene. The mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, the crystal form of the crystal structure of the polypropylene is an alpha crystal form, and the length of the carbon fiber is 0.1 mm-1 mm. In the invention, the welding part 15 of the first shell and the second shell is formed by injection molding of a polypropylene composite material. The energy required for crystallization and melting of the alpha-crystal-form polypropylene is low, so that ultrasonic welding is easier, the welding quality is better, and the welding firmness and air tightness between the first shell and the second shell can be improved. And the polypropylene composite material has high modulus and strength, so that the shell meets the structural strength requirement of the sound production device.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion, and more specifically, to a shell of a sound-generating device, a sound-generating device and an electronic device. Background Art

[0002] The sound module generally includes a module shell and a sound unit disposed in the module shell. The module shell includes a module upper shell and a module lower shell. The sound unit cooperates with the module shell to define a front sound cavity and a rear sound cavity. The module shell is provided with a sound outlet hole connected to the front sound cavity. The module shell is made of metal material and / or plastic material.

[0003] In the related art, a module shell made of PP (polypropylene) + fiber material is proposed. The module shell is light in weight and can meet the requirements of lightweight design of the sound module. However, the structural strength and modulus of the module shell are relatively small, and the sound module is very likely to vibrate during operation, which cannot meet the actual use requirements. Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the invention

[0004] An object of the present invention is to provide a new technical solution for a housing of a sound-generating device.

[0005] According to a first aspect of the present invention, a shell of a sound-generating device is provided. The shell comprises a first shell and a second shell, the first shell and the second shell are both provided with a welding portion, the welding portion of the first shell and the welding portion of the second shell are ultrasonically welded, the welding portion is injection-molded from a polypropylene composite material consisting of carbon fiber and polypropylene, the mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, the crystal form of the crystal structure of the polypropylene is α crystal form, and the length of the carbon fiber is 0.1mm-1mm.

[0006] Optionally, the polypropylene composite material further comprises hollow glass microspheres, and the distribution density of the hollow glass microspheres in the polypropylene composite material is 0.45 g / cm 3 -0.75g / cm 3 .

[0007] Optionally, the carbon fiber has a carbon content of 90%-99.99%, and / or a graphitization degree R of the carbon fiber is 0.85-1.15.

[0008] Optionally, the carbon fiber is sizing treated with a sizing agent, and the sizing agent includes at least one of a polyolefin sizing agent, an epoxy resin sizing agent, and a polyamide sizing agent.

[0009] Optionally, at least one of the first shell and the second shell is integrally formed as a welded portion; or

[0010] At least one of the first shell and the second shell includes a supporting portion, and the supporting portion is injection-moldedly connected to the welding portion.

[0011] Optionally, the supporting portion includes a resin material, and the resin material includes at least one of PP, PA610, PA612, PA1010, PA11, PA12, PA1212, PA1012, PA1111, PA1213, PA1313, PPA, PA4T, PA6T, PA9T, PA10T, PA12T, PA46, ABS, PET, PBT, and PC.

[0012] Optionally, the support portion further comprises a fiber material, the fiber material comprises carbon fiber and / or glass fiber, the resin material is mixed with the fiber material, and the mass ratio of the fiber material to the resin material is 0.10-0.7.

[0013] Optionally, the density of the shell is 0.85 g / cm 3 -1.20g / cm 3 ;

[0014] And / or, a thickness of 10%-90% of an area of ​​the shell is ≤0.3 mm.

[0015] Optionally, the bending modulus of the shell is 5GPa-35GPa;

[0016] And / or, the bending strength of the shell is 50MPa-350MPa.

[0017] Optionally, the thermal deformation temperature of the shell is ≥120°C.

[0018] Optionally, the housing has a waterproof rating of at least 1 ATM.

[0019] According to a second aspect of the present invention, a sound-generating device is provided, which includes a housing of the sound-generating device described in the present invention.

[0020] According to a third aspect of the present invention, an electronic device is provided, which includes the sound generating device of the present invention.

[0021] In an embodiment of the present invention, the welding part of the first shell and the second shell is formed by injection molding of a polypropylene composite material composed of carbon fiber and polypropylene. The crystal structure of the polypropylene is α-crystal. The energy required for the crystallization and melting of α-crystal polypropylene is low, which makes ultrasonic welding easier and the welding quality is better, thereby improving the welding firmness and airtightness between the first shell and the second shell. The melting temperature of the α-crystal polypropylene can not only ensure the high temperature resistance of the polypropylene composite material but also avoid the defects of poor ultrasonic welding. Carbon fiber can significantly improve the strength and modulus of the polypropylene composite material. In reliability verification, it is not easy for the shell to resonate with the sound-emitting monomer. The length of the carbon fiber is 0.1mm-1mm, which makes the shell strong, and the shell is not prone to problems such as exposed fiber and floating fiber during the injection molding process, and the product yield is high. The polypropylene composite material has a high modulus and strength, and the connection structure formed by the two welding parts during ultrasonic welding has high strength and good airtightness.

[0022] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0024] Figure 1 is an exploded view of a sound generating device according to an embodiment of the present invention.

[0025] Figure 2 is a cross-sectional view of a sound generating device according to an embodiment of the present invention.

[0026] Figure 3 is a cross-sectional view of another sound-generating device according to an embodiment of the present invention.

[0027] Description of reference numerals:

[0028] 10. First shell; 111. Front sound cavity; 121. Rear sound cavity; 15. Welding part; 16. Support part; 20. Sound unit; 30. PCB; 40. Second shell. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0030] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0031] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0032] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0033] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0034] According to one embodiment of the present invention, a shell of a sound-generating device is provided. The shell includes a first shell 10 and a second shell 40, each of which is provided with a welding portion 15, the welding portion 15 of the first shell 10 and the welding portion 15 of the second shell 40 are ultrasonically welded, the welding portion 15 is injection-molded from a polypropylene composite material, the polypropylene composite material includes carbon fiber and polypropylene mixed together, the mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, the crystal form of the crystal structure of the polypropylene is α crystal form, and the length of the carbon fiber is 0.1mm-1mm.

[0035] Specifically, Figure 1-Figure 3 As shown, the first shell 10 and the second shell 40 are connected together to form a accommodating cavity therein. The accommodating cavity is used to accommodate the sound-emitting unit 20 and the PCB 30. The sound-emitting unit 20 is connected to the PCB 30. The PCB 30 is connected to the external circuit. A welding portion 15 is provided at the edge of the first shell 10 and the second shell 40. The welding portion 15 is formed by injection molding of a polypropylene composite material. When connected, the two welding portions 15 are arranged opposite to each other, and the two welding portions 15 are melted by ultrasonic welding, and the two welding portions 15 are bonded to each other. After curing, the two welding portions 15 are connected together.

[0036] In this embodiment, the polypropylene composite material includes polypropylene and carbon fiber mixed together. Polypropylene is a polymer formed by addition polymerization of propylene. The crystalline structure of polypropylene is α-crystal. Compared with conventional shell materials such as PC, α-crystal polypropylene has a lower melting temperature, that is, α-crystal polypropylene can melt at a lower temperature, and less energy is required during ultrasonic welding, which enables the shell of the polypropylene composite material to meet the requirements of ultrasonic welding. Optionally, the melting temperature of α-crystal polypropylene is 155°C-170°C, so that the crystalline part of the polypropylene can melt at a lower heat, which is conducive to the realization of the ultrasonic welding process, thereby improving the welding strength between the first shell 10 and the second shell 40. In addition, the welding consistency of each part of the welding portion 15 is good, and it is not easy to form defects such as cold welding and poor air tightness, which can improve the welding air tightness between the first shell 10 and the second shell 40 and improve the waterproof effect of the shell. Moreover, the melting temperature of α-crystalline polypropylene is higher than the maximum operating temperature of the sound-generating device. The melting temperature of α-crystalline polypropylene can be 155°C-170°C, and the maximum operating temperature of the sound-generating device is 120°C. This allows the shell to maintain sufficient rigidity and strength during the normal operation of the sound-generating device to meet the use requirements. Optionally, the melting temperature of polypropylene is 155°C, 160°C, 165°C, 170°C, etc. The above values ​​all make the welding strength of the shell good.

[0037] Carbon fiber is a high-performance fiber material with high strength and high modulus, which is made from organic fibers (such as polyacrylonitrile, viscose fiber or asphalt) through carbonization and other processes. The density of carbon fiber is lower than that of glass fiber, and the carbon fiber reinforced shell structure strength effect is better. Under the condition of meeting the shell strength and modulus requirements, the amount of carbon fiber added to the polypropylene composite material is lower, which is conducive to achieving lightweight shell.

[0038] The mass ratio of the carbon fiber to the polypropylene is 0.17-0.67. When the mass ratio of the carbon fiber to the polypropylene is greater than 0.67, due to the high distribution density of the carbon fiber in the polypropylene composite material, the polypropylene at the welding interface of the welding part 15 is relatively small, resulting in poor welding defects such as cold welding at the welding interface, and the welding strength and welding yield rate decrease. As the mass ratio of the carbon fiber to the polypropylene continues to increase, the melting index of the polypropylene composite material decreases, the viscosity of the melt increases, causing difficulty in injection, and increasing the proportion of products with insufficient glue. The ultrasonic welding strength and welding yield of the welding part 15 of the first shell 10 and the second shell 40 will be significantly reduced; on the contrary, when the mass ratio of the carbon fiber to the polypropylene is less than 0.17, the reinforcing effect of the carbon fiber on the polypropylene composite material is poor, and the shell is prone to resonance in the intermediate frequency stage during the reliability verification process of the sound-generating device, resulting in excessive distortion of the intermediate frequency THD of the sound-generating device. When the mass ratio of the carbon fiber to the polypropylene is 0.11-0.67, the melting temperature of the polypropylene composite material is low, making ultrasonic welding easier, the welding of the two welding parts 15 is firm, and the shell has high strength and modulus, and strong structural firmness. Optionally, the mass ratio of the carbon fiber to the polypropylene is 0.17, 0.20, 0.25, 0.3, 0.35, 0.4, 0.45, 0.46, 0.50, 0.55, 0.60, 0.65, 0.67, etc., and the above values ​​can make the melting temperature of the polypropylene composite material low, ultrasonic welding is easy, the overall structural strength of the formed shell is high, and the modulus and strength of the polypropylene composite material are high.

[0039] In addition, the length of the carbon fiber is 0.1mm-1mm. When the length of the carbon fiber is less than 0.1mm, the strength of the shell will decrease at the same carbon fiber content, causing the shell to be damaged in the drop reliability test; when the length of the carbon fiber is greater than 1mm, during the injection molding process, the shell is prone to problems such as exposed fibers and floating fibers, affecting the product yield. When the length of the carbon fiber is 0.1mm-1mm, the strength of the shell is high, and the shell is not prone to problems such as exposed fibers and floating fibers during the injection molding process, and the product yield is high. Optionally, the length of the carbon fiber is 0.1mm, 0.2mm, 0.3mm, 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc. The above values ​​can all make the shell strong, and the shell is not prone to problems such as exposed fibers and floating fibers during the injection molding process.

[0040] The preparation process of the shell of the present invention may include:

[0041] (1) Preparation of polypropylene composite materials. Polypropylene is added to a twin-screw extruder from the main feed port for melting. After the polypropylene is melted, carbon fiber is added from the side feed port. The carbon fiber and the melted polypropylene are sheared and mixed evenly in the extruder, and then extruded into granules.

[0042] (2) Preparation of the shell. The granulated polypropylene composite material is melted again during injection molding and then injected into a mold to form the first shell 10 and the second shell 40;

[0043] Alternatively, during injection molding, the support portion 16 is firstly formed by injection molding in a mold, and then the welding portion 15 is formed by injection molding at the edge of the support portion 16 , thereby forming the first shell 10 and the second shell 40 .

[0044] (3) Assemble the sound unit 20 and PCB 30 and other components into the accommodation cavity formed by the first shell 10 and the second shell 40. Then, align the two welding parts 15 of the first shell 10 and the second shell 40, and perform ultrasonic welding to connect the two welding parts 15 together.

[0045] It should be noted that the length-to-diameter ratio of carbon fiber is relatively large and its ability to resist shear is not high, so it is usually necessary to add carbon fiber after the polypropylene is melted. This can effectively reduce the damage of the carbon fiber during the mixing process, thereby improving the reinforcement effect of carbon fiber on polypropylene composites.

[0046] In an embodiment of the present invention, the welding part 15 of the first shell 10 and the second shell 40 is formed by injection molding of a polypropylene composite material composed of carbon fiber and polypropylene. The crystal structure of the polypropylene is α-crystal type. The energy required for the crystallization and melting of the α-crystal polypropylene is low, which makes ultrasonic welding easier and the welding quality is better, thereby improving the welding firmness and airtightness between the first shell 10 and the second shell 40. The melting temperature of the polypropylene can not only ensure the high temperature resistance of the polypropylene composite material but also avoid the defects of poor ultrasonic welding. Carbon fiber can significantly improve the strength and modulus of the polypropylene composite material. In reliability verification, it is not easy for the shell to resonate with the sound-emitting monomer 20. The length of the carbon fiber is 0.1mm-1mm, which makes the shell strong, and the shell is not prone to problems such as exposed fiber and floating fiber during the injection molding process, and the product yield is high. The polypropylene composite material has a high modulus and strength, and the connection structure formed by the two welding parts 15 during ultrasonic welding has high strength and high yield.

[0047] In a specific embodiment of the present invention, the polypropylene composite material further comprises hollow glass microspheres, and the distribution density of the hollow glass microspheres in the polypropylene composite material is 0.45 g / cm 3 -0.75g / cm 3 .

[0048] In this embodiment, when preparing a polypropylene composite material, hollow glass microspheres and carbon fibers are added to a polypropylene melt; after mixing, a polypropylene composite material is finally formed. Since hollow glass microspheres may be shear-damaged during the mixing process, the hollow glass microspheres are added after the carbon fibers are added to minimize the shear damage of the hollow glass microspheres during the mixing process. The hollow glass microspheres can significantly reduce the density of the polypropylene composite material and meet the demand for lightweight shells.

[0049] It should be noted that when the mass percentage of the hollow glass microspheres in the polypropylene composite material is less than 1%, the effect of reducing the density of the polypropylene composite material is not obvious; on the contrary, when the mass percentage of the hollow glass microspheres in the polypropylene composite material is greater than 20%, the impact resistance of the polypropylene composite material will decrease, and the shell will be easily damaged in the drop reliability test of the sound-generating device. In this embodiment, the mass percentage of the hollow glass microspheres is 1%-20%. Within this range, the density of the polypropylene composite material can be effectively reduced, and the connection strength of the two welding parts 15 is high, and the shell is not easy to be damaged. Optionally, the mass percentage of the hollow glass microspheres is 1%, 2%, 4%, 6%, 9%, 10%, 12%, 13%, 14%, 16%, 17%, 18%, 19%, 20%. The above values ​​can effectively reduce the density of the polypropylene composite material, and the connection strength of the two welding parts 15 is high, and the shell is not easy to be damaged.

[0050] The distribution density of hollow glass microspheres in polypropylene composite materials refers to the mass of hollow glass microspheres per unit volume of polypropylene composite materials. The distribution density of hollow glass microspheres is less than 0.45g / cm 3 When the density of the review material is reduced, the effect is not obvious; on the contrary, the distribution density of the hollow glass microspheres is greater than 0.75g / cm 3 When the hollow glass microspheres are placed in the polypropylene composite material, the impact resistance of the composite material will be reduced. In the drop reliability test of the sound-generating device, the shell is easily damaged. In this embodiment, the distribution density of the hollow glass microspheres in the polypropylene composite material is 0.45 g / cm 3 -0.75 / cm 3 Within this range, the density of the polypropylene composite material can be effectively reduced, and the connection strength of the two welding parts 15 is high, and the shell is not easily damaged. Optionally, the distribution density of the hollow glass microbeads in the polypropylene composite material is 0.45 g / cm 3 , 0.5g / cm 3 , 0.6g / cm 3 , 0.7g / cm 3 , 0.75g / cm 3The above values ​​can effectively reduce the density of the polypropylene composite material and increase the connection strength of the two welding portions 15, so that the shell is not easily damaged.

[0051] In a specific embodiment of the present invention, the carbon content of the carbon fiber is 90%-99.99%.

[0052] And / or, the graphitization degree R of the carbon fiber is 0.85-1.15.

[0053] Specifically, the lower the carbon content of the carbon fiber, the lower the modulus of the carbon fiber; conversely, the higher the carbon content of the carbon fiber, the higher the modulus of the carbon fiber. In this embodiment, the carbon content of the carbon fiber is 90%-99.99%. Within the range, under the same mass content conditions, the modulus of the polypropylene composite material is high, and the overall structural strength of the shell is high. Optionally, the carbon content of the carbon fiber is 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.99%, etc. The above values ​​can all make the modulus of the polypropylene composite material high and the overall structural strength of the shell high.

[0054] The graphitization degree R value refers to the value of 1360cm when the Raman spectrum is used to test the carbon fiber. -1 The peak intensity of 1583cm -1 The ratio of peak intensity. The degree of graphitization is inversely proportional to the R value. The smaller the R value, the higher the degree of graphitization, the higher the degree of graphitization of the carbon fiber, the higher the modulus along the fiber direction, and the higher the effect of improving the modulus of the polypropylene composite material. When the R value is greater than 1.15, the graphitization degree of the carbon fiber is too small, and the modulus improvement effect on the polypropylene composite material is poor. When the R value is less than 0.85, the degree of graphitization of the carbon fiber is high, and the raw material requirements and processing technology requirements for the carbon fiber are both high, which increases the cost. In this embodiment, the graphitization degree R value of the carbon fiber is 0.85-1.15. Within this range, the modulus of the polypropylene composite material is high and the cost of the carbon fiber is low, and the cost of the polypropylene composite material is low. Optionally, the graphitization degree R value of the carbon fiber is 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15. The above values ​​can all make the modulus of the polypropylene composite material high and the cost low.

[0055] In a specific embodiment of the present invention, the carbon fiber is sizing treated with a sizing agent, and the sizing agent includes at least one of a polyolefin sizing agent, an epoxy resin sizing agent, and a polyamide sizing agent.

[0056] In this embodiment, the surface of the carbon fiber is inert, has poor compatibility with polypropylene, and has low bonding strength. In the preparation process of polypropylene composite materials, the surface of the carbon fiber needs to be surface treated to improve the compatibility of the carbon fiber and polypropylene. The carbon fiber is sizing treated with a sizing agent. The sizing agent includes at least one of a polyolefin sizing agent, an epoxy resin sizing agent, and a polyamide sizing agent. The above sizing agents can all improve the bonding strength of the carbon fiber and polypropylene, and improve the compatibility of the carbon fiber and polypropylene.

[0057] In a specific embodiment of the present invention, the entirety of at least one of the first shell and the second shell is a welding portion.

[0058] In other words, in this embodiment, the first shell 10 and / or the second shell 40 are all made of a polypropylene composite material by integral injection molding, and the polypropylene composite material includes polypropylene and carbon fiber mixed together, the mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, the crystal form of the crystalline structure of the polypropylene is α crystal form, and the length of the carbon fiber is 0.1-1mm. As mentioned above, the shell has the characteristics of high modulus, high strength, light weight, easy ultrasonic welding, and high welding yield. For example, the first shell 10 is all made of a polypropylene composite material by integral injection molding, and part of the structure of the second shell 40 is made of a polypropylene composite material by integral injection molding; or, part of the structure of the first shell 10 is made of a polypropylene composite material by integral injection molding, and the second shell 40 is all made of a polypropylene composite material by integral injection molding; or, both the first shell 10 and the second shell 40 are all made of a polypropylene composite material by integral injection molding.

[0059] In a specific embodiment of the present invention, at least one of the first shell 10 and the second shell 40 further includes a support portion 16 , and the support portion 16 and the welding portion 15 are integrally injection molded.

[0060] Specifically, if Figure 1 , Figure 2 As shown, the first shell 10 and / or the second shell 40 are formed by double-shot molding. For example, the support portion 16 is formed in one shot, and the welding portion 15 is formed on the support portion 16 in the second shot. After curing, the support portion 16 and the welding portion 15 are connected together. In this embodiment, the support portion 16 can be processed into a set shape according to actual needs to meet the sound requirements of different sound-emitting devices. The welding portion 15 is formed at the edge of the support portion 16. The welding portion 15 of the first shell 10 and the second shell 40 is used for ultrasonic welding to connect and form the shell. In this setting, different parts of the first shell 10 and / or the second shell 40 are made of different materials according to different functions, and the different materials are molded by integral injection molding. The processing technology of the first shell 10 and / or the second shell 40 is simple and the structural strength is high.

[0061] In a specific embodiment of the present invention, the supporting portion 16 includes a resin material, and the resin material includes at least one of PP, PA610, PA612, PA1010, PA11, PA12, PA1212, PA1012, PA1111, PA1213, PA1313, PPA, PA4T, PA6T, PA9T, PA10T, PA12T, PA46, ABS, PET, PBT, and PC.

[0062] When preparing the support part 16, any one of the above materials can be selected, or at least two of the above materials can be mixed together. The above materials can be processed into a set structure according to the sound generation requirements of the sound generation device.

[0063] In a specific embodiment of the present invention, the support portion further comprises a fiber material, the fiber material comprises carbon fiber and / or glass fiber, the resin material is mixed with the fiber material, and the mass ratio of the fiber material to the resin material is 0.10-0.7.

[0064] In this embodiment, the fiber material is, for example, carbon fiber and / or glass fiber. The resin material and the fiber material are mixed together to form a polypropylene composite material, and the fiber material can significantly improve the modulus and strength of the polypropylene composite material. When the mass ratio of the fiber material to the resin material is less than 0.10, the fiber material has a small improvement on the modulus and strength of the polypropylene composite material; on the contrary, when the mass ratio of the fiber material to the resin material is greater than 0.7, the density of the formed polypropylene composite material is large and does not meet the requirements of lightweight shell. In this embodiment, the mass ratio of the fiber material to the resin material is 0.10-0.7, within the range, the polypropylene composite material has both high strength and modulus and the mass of the formed shell is light. Optionally, the mass ratio of the fiber material to the resin material is 0.1, 0.15, 0.2, 0.25, 0.30, 0.40, 0.50, 0.60, 0.70, etc., and the above values ​​all make the polypropylene composite material have both high strength and modulus and the mass of the formed shell is light.

[0065] In a specific embodiment of the present invention, the density of the shell is 0.85 g / cm 3 -1.20g / cm 3 ;

[0066] And / or, a thickness of 10%-90% of an area of ​​the shell is ≤0.3 mm.

[0067] Specifically, in this embodiment, the material of the shell includes α-crystalline polypropylene, which has a relatively low density, so that the overall density of the shell is 0.85 g / cm 3 -1.20g / cm3 Within this range, at the same volume, the shell has a smaller mass and sufficient modulus and strength, meeting the requirement of lightweight shell. Optionally, the density of the shell is 0.85g / cm 3 , 0.90g / cm 3 , 1.0g / cm 3 , 1.10g / cm 3 , 1.20g / cm 3 The above values ​​can make the shell light and have sufficient modulus and strength.

[0068] The thickness of 10%-90% of the area of ​​the shell is ≤0.3mm. In other words, the thickness of 10%-90% of the surface area of ​​the shell is ≤0.3m. For example, the shell includes a top wall and a side wall, and the area with a thickness of ≤0.3m is located on the top wall and / or the side wall; or the shell is a sheet structure, and the area with a thickness of ≤0.3m is located at least partially in the sheet structure. Optionally, the shell is made of injection molding of a polypropylene composite material. Since the polypropylene composite material has a high modulus and strength, the shell can be made at least partially thinner, thereby increasing the volume of the internal accommodating cavity of the shell, and then increasing the volume of the sound cavity of the sound-emitting device, thereby improving the sound effect of the sound-emitting device.

[0069] In a specific embodiment of the present invention, along the vibration direction of the vibration system of the sound-emitting unit 20, the thickness of at least part of the shell opposite to the sound-emitting unit 20 is ≤0.3mm. This arrangement allows the shell to have a larger space in the vibration direction of the vibration system, allowing the vibration amplitude of the sound-emitting unit 20 to be larger, effectively improving the sound effect. Optionally, the thickness of the shell is 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, etc., and the above values ​​can all make the space inside the shell larger.

[0070] In addition, in order to make the space of the front sound cavity and / or the rear sound cavity larger, the shell of the prior art usually sets a steel sheet in the vibration direction of the shell to reduce the thickness. In the present invention, since the modulus and strength of the polypropylene composite material are large enough, the part of the shell in the vibration direction of the vibration system can be made thinner, for example, the thickness is ≤0.3mm, thereby increasing the space of the front sound cavity and / or the rear sound cavity. This method does not need to set a steel sheet, and the shell can be integrally formed by injection molding, which makes the preparation process of the shell simpler. Moreover, the shell in the present invention is a uniform overall structure with good structural stability, and there will be no phenomenon that the structural strength and acoustic performance are affected by cracks between the steel sheet and the shell.

[0071] In a specific embodiment of the present invention, the bending modulus of the shell is 5 GPa-35 GPa.

[0072] The bending modulus reflects the ability of a material to resist deformation when subjected to a bending load. If the bending modulus of the shell is too low, for example, less than 5 GPa, the shell is prone to local vibration, which is easy to resonate with the vibration of the sound-emitting monomer 20, making the sound-emitting device have poor sounding effect; if the bending modulus of the shell is too high, for example, greater than 35 GPa, the processing difficulty of the shell will increase and the product yield will decrease. For example, when a shell is prepared using a polypropylene composite material, it is necessary to increase the amount of carbon fiber added, for example, the mass ratio of carbon fiber to polypropylene is greater than 0.67, which will cause the viscosity of the polypropylene melt to be too large, and it is easy to expose the fiber and lack of glue during the injection molding process. In this embodiment, the bending modulus of the shell is 5 GPa-35 GPa. Within this range, it can not only avoid the resonance between the shell and the sound-emitting monomer 20, but also reduce the processing difficulty of the shell, reduce shell defects, and improve product yield. Optionally, the bending modulus of the shell is 5 GPa, 10 GPa, 15 GPa, 20 GPa, 25 GPa, 30 GPa, 35 GPa. The above values ​​can avoid resonance between the shell and the sound-emitting unit 20 and reduce the difficulty of processing the shell, thereby improving the product yield.

[0073] In a specific embodiment of the present invention, the bending strength of the shell is 50MPa-350Mpa.

[0074] Bending strength is the maximum normal stress that a material can withstand when it reaches a specified deflection or breaks under a bending load. When the bending strength of the shell is lower than 50MPa, the shell is prone to deformation or even fracture when impacted; when the bending strength is higher than 350MPa, the shell has poor fluidity during injection molding and is difficult to process. In this embodiment, the bending strength of the shell is 50MPa-350Mpa. Within this range, the shell is not easily deformed when impacted, and the shell has low processing difficulty and high product yield. Optionally, the bending strength of the shell is 50MPa, 100MPa, 200MPa, 300MPa, 350Mpa, etc. The above values ​​all make the shell have excellent impact resistance and low processing difficulty, and high product yield.

[0075] In a specific embodiment of the present invention, the thermal deformation temperature of the shell is ≥120°C.

[0076] The heat deformation temperature reflects the ability of the material to resist deformation under heat and load conditions. The higher the heat deformation temperature of the shell, the more it indicates that the shell can maintain structural stability under higher conditions. In this embodiment, the heat deformation temperature of the shell is ≥120°C, so that the shell has strong high temperature resistance and is not easy to deform during high temperature and high humidity reliability and high power reliability verification. Optionally, the heat deformation temperature of the shell is 120°C, 130°C, 140°C, 150°C, etc. The above values ​​all make the shell have strong high temperature resistance and is not easy to deform during high temperature and high humidity reliability and high power reliability verification.

[0077] In a specific embodiment of the present invention, the waterproof rating of the housing is at least 1 ATM.

[0078] In this embodiment, the welding portion 15 of the first shell 10 and the welding portion 15 of the second shell 40 are connected by ultrasonic welding. The welding portion 15 is formed by injection molding of a polypropylene composite material. The polypropylene composite material includes carbon fiber and polypropylene mixed together. The crystal form of the crystalline structure of the polypropylene is α crystal form, and the length of the carbon fiber is 0.1-1mm. Therefore, the heat required for melting the welding interface of the two welding portions 15 is lower, the energy of ultrasonic welding can be lower, and welding is easier, and it is not easy to have problems such as cold welding and air gap. In addition, the mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, which significantly improves the strength and modulus of the welding portion 15. In the above manner, the shell will not deform or leak at a water pressure of at least 10 meters.

[0079] According to a second embodiment of the present invention, a sound-generating device is provided, which includes the housing of the sound-generating device described in the present invention.

[0080] like Figure 1-Figure 3 As shown, the sound-emitting device of the present invention includes a shell, a sound-emitting unit 20 and a PCB30. The shell includes a first shell 10 and a second shell 40. The first shell 10 and the second shell 40 are connected together to form a accommodating cavity therein. The accommodating cavity is used to accommodate the sound-emitting unit 20 and at least part of the PCB30. A front sound cavity 111 is formed between the first shell 10 and the sound-emitting unit 20. The front sound cavity 111 has a sound outlet hole. A rear sound cavity 121 is formed between the second shell 40 and the sound-emitting unit 20. The sound-emitting unit 20 is connected to the PCB30. The PCB30 is connected to an external circuit. The edges of the first shell 10 and the second shell 40 are both provided with welding portions 15. The welding portion 15 is formed by injection molding of an alloy composite material containing carbon fiber and an alloy material. The welding portions 15 of the first shell 10 and the second shell 40 are connected together by ultrasonic welding.

[0081] The sound-generating device has the characteristics of high structural strength, good high temperature resistance and good sound-generating effect.

[0082] According to a third embodiment of the present invention, an electronic device is provided. The electronic device includes the sound-generating device of the present invention. The electronic device has the characteristic of good durability. Optionally, the electronic device is a computer, a mobile phone, a watch, a television, a speaker, an AR device, a VR device, etc.

[0083] The shell of the sound-generating device and the sound-generating device according to the embodiment of the present invention are described in detail below in combination with specific embodiments and comparative examples. It is worth noting that the following description is only exemplary and not a specific limitation to the present invention.

[0084] Comparative Example 1

[0085] A shell is formed by injection molding using 80 wt % of PC material and 20 wt % of glass fiber, and the shell is assembled with a sound-generating monomer 20 to obtain a sound-generating device.

[0086] Comparative Example 2

[0087] A shell is formed by injection molding using 85.5wt% of PP (with a β-crystal structure) material and 14.5wt% of carbon fiber, and the shell is assembled with a sound-generating monomer 20 to obtain a sound-generating device.

[0088] Example 1

[0089] A shell is formed by injection molding using 85.5wt% of PP (the crystal structure is α-crystal structure) and 14.5wt% of carbon fiber, and the obtained shell is assembled with the sound-generating monomer 20 to obtain a sound-generating module.

[0090] Example 2

[0091] A shell is formed by injection molding of 70.5wt% PP (with an α-crystal structure), 14.5wt% carbon fiber and 15% hollow glass microspheres, and the shell is assembled with a sound-generating monomer 20 to obtain a sound-generating module.

[0092] Example 3

[0093] A shell is formed by injection molding using 80wt% of PP (the crystal structure is α-crystal structure) and 20wt% of carbon fiber, and the obtained shell is assembled with the sound-generating monomer 20 to obtain a sound-generating module.

[0094] Example 4

[0095] A shell is formed by injection molding using 70 wt % of PP (the crystal structure is α crystal) and 30 wt % of carbon fiber, and the obtained shell is assembled with the sound-generating monomer 20 to obtain a sound-generating module.

[0096] Example 5

[0097] A shell is formed by injection molding using 60wt% of PP (the crystal structure is α-crystal structure) and 40wt% of carbon fiber, and the obtained shell is assembled with the sound-generating monomer 20 to obtain a sound-generating module.

[0098] It should be noted that the outer dimensions of the shells in the comparative examples and the embodiments are consistent. For the convenience of comparison, the raw material proportions of comparative examples 1-2 and embodiments 1-5 are shown in Table 1.

[0099] Table 1 - Raw material ratios of the shells of the embodiments and comparative examples

[0100]

[0101] The shells of comparative examples 1-2 and the shells of embodiments 1-5 were tested for heat deformation temperature, density, bending modulus, bending strength, dyne value, UV adhesive strength and reliability, and the test results are shown in Table 2, Table 3 and Table 4.

[0102] The test conditions and standards are as follows:

[0103] (1) Flexural modulus and flexural strength test: The test is carried out in accordance with GB / T 9341-2008, the standard for determination of flexural properties of plastics.

[0104] (2) Heat deformation temperature test: The test shall be conducted in accordance with GB / T 1634.2-2004 Plastics - Determination of heat deformation temperature - Part 2: Plastics, hard rubber and long fiber reinforced alloy composites.

[0105] (3) Density test method: Test in accordance with GB / T 1033.1-2008 Plastics - Determination of density of non-foamed plastics - Part 1: Immersion method, liquid pycnometer method and titration method, using the immersion method.

[0106] (4) High temperature and high humidity reliability test: The sound-generating device is placed in a test environment with a temperature of 85°C and a humidity of 85% for 48 hours, and then the sound-generating device is removed to test its acoustic performance.

[0107] (5) High-power reliability test: The sound-generating device is operated at 1.1 times the rated power for 72 hours, and then its acoustic performance is tested.

[0108] (6) 10-meter waterproof verification test: Place the sound-generating device in water at a depth of 10 meters for 30 minutes, then take it out and test its acoustic performance.

[0109] (7) 2-meter drop reliability test: The sound-generating device is placed at a height of 2 meters and dropped to the ground to cause a collision. The integrity of the shell of the sound-generating device is then observed and its acoustic performance is tested.

[0110] Table 2 - Performance test comparison table of embodiments and comparative examples

[0111] name Heat Deflection Temperature density Flexural modulus Bending Strength ℃ <![CDATA[g / cm 3 ]]> Gpa Mpa Comparative Example 1 141 1.35 5.5 170 Comparative Example 2 125 0.95 4.4 49 Example 1 144 0.95 5.1 72 Example 2 146 0.89 5.2 70 Example 3 150 0.99 7.5 85 Example 4 152 1.06 13 110 Example 5 155 1.14 19 190

[0112] As can be seen from Table 2, the heat deformation temperature of the shells of Examples 1-5 and the heat deformation temperature of the shells of Comparative Examples 1-2 are both ≥120°C. The bending strength of the shells of Examples 1-5 and the bending strength of the shell of Comparative Example 1 are both between 50MPa-350Mpa. The bending modulus of the shells of Examples 1-5 and the bending modulus of the shell of Comparative Example 1 are both between 5GPa-35Gpa. The shell of Comparative Example 2 contains β-crystalline polypropylene. Since the strength and modulus of β-crystalline polypropylene are relatively low, the bending modulus and bending strength of the shell of Comparative Example 2 are relatively small.

[0113] In addition, the density of the shells of Examples 1-5 and Comparative Example 2 is ≤1.14 g / cm 3 The shell of Comparative Example 1 contains PC material. Since the density of PC material is high and the mass percentage reaches 70%, the density of the shell of Comparative Example 1 is greater than 1.20 g / cm 3 , this density does not meet the requirement of lightweight shell.

[0114] It can be seen that the shells of Examples 1-5 are injection molded from polypropylene composite materials, which include carbon fibers and polypropylene mixed together, the mass ratio of the carbon fibers to the polypropylene being 0.17-0.67, the crystal form of the crystalline structure of the polypropylene being α-crystal form, and the length of the carbon fibers being 0.1-1 mm. The melting temperature of polypropylene is relatively low, and the welding of the shell is more secure during ultrasonic welding. The bending modulus and bending strength of the shells of Examples 1-5 are both high, indicating that the structural strength of the shell is high. The heat deformation temperature of the shells of Examples 1-5 is high, indicating that the strength of the shell decreases little during high-temperature operation, and the structural stability is strong. The density of the shells of Examples 1-5 is relatively small, meeting the lightweight requirements of the shell.

[0115] Although some properties of the shells of Examples 1-2, such as the bending modulus, bending strength, and heat deformation temperature of the shell of Example 1, and the heat deformation temperature and density of the shell of Example 2, meet the requirements, the density of the shell of Example 1 is too large and does not meet the requirements of lightweight shell; the bending modulus and bending strength of the shell of Example 2 are low, and local parts of the shell are prone to vibrate, which is easy to resonate with the vibration of the sound-emitting unit 20, resulting in poor sound effect of the sound-emitting device.

[0116] In addition to the above tests, the process performance of the shells of Examples 1-5 and Comparative Examples 1-2 was also tested, see Table 3 for details.

[0117] Table 3 - Comparison of process performance tests of the shells of the embodiment and the comparative example

[0118] name Ultrasonic flaw detector testing Welding yield Injection molding Injection molding yield Comparative Example 1 Ultrasonic welding OK 100％ Molding OK 100％ Comparative Example 2 Ultrasonic welding OK 100％ Molding OK 100％ Example 1 Ultrasonic welding OK 100％ Molding OK 100％ Example 2 Ultrasonic welding OK 100％ Molding OK 100％ Example 3 Ultrasonic welding OK 100％ Molding OK 100％ Example 4 Ultrasonic welding OK 100％ Molding OK 100％ Example 5 Ultrasonic welding OK 100％ Molding OK 100％

[0119] As can be seen from Table 3, the yield of the injection molding process and the yield of the ultrasonic welding process of the shells of Examples 1-5 and Comparative Examples 1-2 are both high.

[0120] Table 4 - Comparison of reliability tests of the sound-generating devices of the embodiment and the comparative example

[0121] name High temperature and high humidity reliability High power reliability 10m waterproof verification 2m drop reliability Comparative Example 1 OK OK OK OK Comparative Example 2 NG NG OK OK Example 1 OK OK OK OK Example 2 OK OK OK OK Example 3 OK OK OK OK Example 4 OK OK OK OK Example 5 OK OK OK OK

[0122] Table 4 is a reliability test comparison table of the embodiments and comparative examples. As can be seen from Table 4, the housings of embodiments 1-5 and the housing of comparative example 1 have passed the tests of high temperature and high humidity reliability, high power reliability, 10m waterproof verification, and 2m drop reliability.

[0123] The shell of Comparative Example 2 uses β-crystal PP material and carbon fiber composite material. Compared with α-crystal polypropylene, the strength and rigidity of β-crystal PP material are lower, so the bending modulus and bending strength of the shell of Comparative Example 2 are lower. The rigidity of the shell of Comparative Example 2 is insufficient. In the high-temperature and high-humidity reliability test and the high-power reliability test, the shell is easy to resonate with the sound-emitting monomer and fails the test.

[0124] In summary, the shell of Comparative Example 1 is formed by injection molding of 80wt% PC material and 20wt% glass fiber. Although it can meet the requirements of structural strength, reliability, air tightness and waterproofness, the density of PC material is relatively large, making it difficult to meet the lightweight design requirements of the shell. The shell of Comparative Example 2 is formed by injection molding of 85.5wt% β-crystal PP material and 14.5wt% carbon fiber. Although it can meet the requirements of thermal deformation temperature, density, 10-meter waterproof test, 2m drop test, etc., due to the lower strength and rigidity of β-crystal PP material, the bending modulus and bending strength of the shell of Comparative Example 2 are low. In the high-temperature and high-humidity reliability test and the high-power reliability test, the shell is easy to resonate with the sound-emitting monomer and fails the test.

[0125] The shells of Examples 1-5 are formed by injection molding of polypropylene and carbon fiber materials, with a mass ratio of carbon fiber to polypropylene of 0.17-0.67. Polypropylene has a low melting point, and the energy required for ultrasonic welding is lower, making it easier to weld, thereby improving the welding firmness and airtightness between the first shell 10 and the second shell 40. In addition, since polypropylene has a low density, the density of the shell is 0.85 g / cm 3 -1.20g / cm 3range, so that the lightweight design of the shell can be achieved. The heat deformation temperature of the shell is ≥120℃, which can make the shell have a small drop in strength during high-temperature operation and strong structural stability. Moreover, the above-mentioned polypropylene composite material includes carbon fiber material, which has a high modulus and strength, thereby improving the structural strength of the shell. In addition, the bending modulus of the shell is in the range of 5GPa-35Gpa, which can not only avoid the resonance between the shell and the sound-emitting monomer 20, but also reduce the processing difficulty of the shell, reduce shell defects, and improve product yield. The bending strength of the shell is in the range of 50MPa-350Mpa. When the shell is impacted, it is not easy to deform, and the processing difficulty of the shell is small, and the product yield is high. Since the shell is formed by injection molding of polypropylene and carbon fiber materials, the ultrasonic welding effect of the shell is good, and the heat deformation temperature is high, which makes the shell not easy to deform in high temperature and high humidity reliability, high power reliability verification, 10m waterproof verification, and 2m drop reliability test.

[0126] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0127] Although some specific embodiments of the present invention have been described in detail by way of example, it will be appreciated by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It will be appreciated by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A housing of a sound-generating device, characterized in that: The invention comprises a first shell and a second shell, wherein the first shell and the second shell are both provided with a welding part, the welding part of the first shell and the welding part of the second shell are connected by ultrasonic welding, the welding part is formed by injection molding of a polypropylene composite material consisting of carbon fiber and polypropylene, the mass ratio of the carbon fiber to the polypropylene is 0.17-0.67, the crystal form of the crystal structure of the polypropylene is α crystal form, and the length of the carbon fiber is 0.1mm-1mm.

2. The housing of the sound-generating device according to claim 1, characterized in that: The polypropylene composite material further comprises hollow glass microspheres, and the distribution density of the hollow glass microspheres in the polypropylene composite material is 0.45 g / cm 3 -0.75g / cm 3 .

3. The housing of the sound-generating device according to claim 1, characterized in that: The carbon fiber has a carbon content of 90%-99.99%, and / or a graphitization degree R of 0.85-1.

15.

4. The housing of the sound-generating device according to claim 1, characterized in that: The carbon fiber is sizing treated with a sizing agent, and the sizing agent includes at least one of a polyolefin sizing agent, an epoxy resin sizing agent, and a polyamide sizing agent.

5. The housing of the sound-generating device according to claim 1, characterized in that: The entirety of at least one of the first shell and the second shell is a welded portion; or At least one of the first shell and the second shell includes a supporting portion, and the supporting portion is injection-moldedly connected to the welding portion.

6. The housing of the sound-generating device according to claim 5, characterized in that: The supporting portion includes a resin material, and the resin material includes at least one of PP, PA610, PA612, PA1010, PA11, PA12, PA1212, PA1012, PA1111, PA1213, PA1313, PPA, PA4T, PA6T, PA9T, PA10T, PA12T, PA46, ABS, PET, PBT, and PC.

7. The housing of the sound-generating device according to claim 6, characterized in that: The support part further comprises a fiber material, wherein the fiber material comprises carbon fiber and / or glass fiber, and the resin material is mixed with the fiber material, and a mass ratio of the fiber material to the resin material is 0.10-0.

7.

8. The housing of the sound-generating device according to claim 1, characterized in that: The density of the shell is 0.85 g / cm 3 -1.20g / cm 3 ; And / or, a thickness of 10%-90% of an area of ​​the shell is ≤0.3 mm.

9. The housing of the sound-generating device according to claim 1, characterized in that: The bending modulus of the shell is 5GPa-35GPa; And / or, the bending strength of the shell is 50MPa-350MPa.

10. The housing of the sound-generating device according to claim 1, characterized in that: The heat deformation temperature of the shell is ≥120°C.

11. The housing of the sound-generating device according to any one of claims 1 to 10, characterized in that: The housing has a waterproof rating of at least 1ATM.

12. A sound-generating device, characterized in that: A housing comprising the sound emitting device according to any one of claims 1 to 11.

13. An electronic device, characterized in that: Comprising the sound-generating device as claimed in claim 12.

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