Mobile phone camera transmission shaft assembly structure and manufacturing method

Abstract

The application provides a mobile phone camera transmission shaft assembly structure and manufacturing method, and relates to the technical field of mobile phone camera parts. To solve the problems of poor wear resistance, low transmission precision and insufficient structural strength of the existing shaft sleeve, the application comprises a base and a cover plate. The base is made of plastic material, and a riveting structure formed by interference riveting of a bottom plate and a front shaft sleeve is fixed on the base. The cover plate is fixed with a rear shaft sleeve. The front shaft sleeve and the rear shaft sleeve are both made of metal material, and a PTFE and molybdenum disulfide mixed self-lubricating wear-resistant coating with a thickness of 0.06-0.09 mm is arranged on the inner wall of the transmission groove of the hollow cylindrical transmission part. The base and the cover plate are mutually covered, and the front shaft sleeve and the rear shaft sleeve are coaxially arranged. During manufacturing, the base and the cover plate fixed part are formed by injection molding after positioning the parts by pre-pressing cores, or are assembled after step injection molding. The application has reasonable structure design, and tests show that the wear resistance, transmission precision and structural strength of the application all meet the design requirements, and the application can be mass-produced.

Description

Technical Field

[0001] This invention relates to the field of mobile phone camera component technology, specifically to a mobile phone camera drive shaft assembly structure and manufacturing method. Background Technology

[0002] With the continuous upgrading of smartphone camera functions, retractable and rotating camera modules are gradually becoming mainstream configurations. In these camera modules, the drive shaft is the core component that realizes mechanical movements, and the drive shaft assembly structure, as the cooperating and protective structure of the drive shaft, directly affects the smoothness and stability of camera movements as well as the lifespan of the module.

[0003] The existing mobile phone camera drive shaft assembly structure has the following defects: First, most drive shaft assembly structures are made of a single plastic material, which is prone to wear and deformation under long-term high-frequency transmission friction, resulting in an increased gap between the drive shaft and the drive shaft assembly structure, causing shaking or abnormal noise, affecting the stability during shooting; Second, the transmission accuracy is insufficient. Due to the low processing precision of the inner wall of the bushing and the thermal expansion and contraction characteristics of the material, the fit clearance between the drive shaft and the drive shaft assembly structure is prone to change under different ambient temperatures, thus affecting the positioning accuracy of the camera movement; Third, the structural strength is insufficient. When the mobile phone is subjected to accidental impact, the drive shaft assembly structure is prone to breakage, leading to camera module failure.

[0004] In view of the shortcomings of the existing technology, there is an urgent need for a mobile phone camera drive shaft assembly structure with high wear resistance, high transmission accuracy and high structural strength to solve the problems existing in the current products. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of poor wear resistance, low transmission accuracy, and insufficient structural strength of the existing mobile phone camera drive shaft sleeve, and to provide a mobile phone camera drive shaft assembly structure and manufacturing method with reasonable structural design, strong wear resistance, high transmission accuracy, and stable structure.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A mobile phone camera drive shaft assembly structure includes a base and a cover plate. The base is made of plastic and has a riveting structure fixed on it. The riveting structure includes an interference-fit base plate and a front axle sleeve. A rear axle sleeve is fixed on the cover plate. Both the front and rear axle sleeves are made of metal and have hollow drive parts. The center of each drive part has a drive groove for cooperating with the drive shaft. The inner wall of the drive groove is coated with a self-lubricating and wear-resistant coating. The drive groove of the front axle sleeve and the drive groove of the rear axle sleeve are coaxially arranged.

[0007] Furthermore, the self-lubricating wear-resistant coating is a mixed coating of PTFE and molybdenum disulfide.

[0008] Furthermore, the thickness of the hybrid coating is 0.06–0.09 mm.

[0009] Furthermore, the cover plate has a flow channel inside, and the cover plate also includes a fixing part that is injection molded and cured in the flow channel, the fixing part integrally fixing the rear axle sleeve to the cover plate.

[0010] Furthermore, the injection molding material of both the base and the fixing part is a mixture of modified PPS and 30% glass fiber.

[0011] Furthermore, both the front and rear axle bushings are made of stainless steel.

[0012] Furthermore, the roundness of the transmission groove is ≤0.005mm, and the coaxiality of the transmission groove relative to the outer circle of the transmission part is ≤0.005mm; the straightness error of the axis of the transmission groove is ≤0.005mm, and the parallelism error of its two end faces is ≤0.01mm.

[0013] The present invention also provides a manufacturing method for manufacturing the above-mentioned mobile phone camera drive shaft assembly structure, comprising the following steps: S1: Rivet the front axle sleeve to the base plate to form a riveting structure; position the rear axle sleeve and the riveting structure on the first pre-pressing core, and then position and install the cover plate on the first pre-pressing core to form a pre-assembled assembly; S2: The pre-assembled component is placed into the first injection mold, and the base and the fixing part filled in the cover plate flow channel are formed simultaneously by injection molding, wherein the base covers and fixes the riveting structure, and the fixing part fixes the rear bushing to the cover plate. S3: After demolding, separate the cover plate from the base, remove the first pre-pressed core, and then assemble and fix the cover plate and the base to obtain the mobile phone camera drive shaft assembly structure.

[0014] This invention also provides another manufacturing method for manufacturing the above-mentioned mobile phone camera drive shaft assembly structure, comprising the following steps: S1: The front axle sleeve is riveted and fixed to the base plate to form a riveting structure; the riveting structure is placed into the second injection mold, and the second pre-pressed core in the second injection mold is used to position the riveting structure, and the base is injection molded to form the base, which covers and fixes the riveting structure. S2: Place the rear axle sleeve and cover plate into the third injection mold. First, position and install the rear axle sleeve on the third pre-compression core of the third injection mold. Then, position and install the cover plate on the third pre-compression core. Inject and mold a fixing part that fills the flow channel of the cover plate. The fixing part fixes the rear axle sleeve to the cover plate. S3: Assemble and fix the cover plate to the base to obtain the mobile phone camera drive shaft assembly structure.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent wear resistance: The bushing body is made of stainless steel and coated with a PTFE+molybdenum disulfide self-lubricating wear-resistant coating on the inner wall, which significantly reduces the coefficient of friction with the drive shaft. At the same time, the base adopts a glass fiber reinforced structure, which improves the wear resistance, effectively reduces wear and deformation after long-term use, and extends the service life.

[0016] 2. High transmission precision: The transmission groove is machined with high precision, and the error is controlled at the micron level. The roundness and coaxiality of the transmission groove are ≤0.005mm, which ensures that the transmission shaft can transmit accurately in various environments and improves the positioning accuracy of the camera's movements.

[0017] 3. High structural strength: The stainless steel bushing body and the injection molded base combine to give the overall structure both high strength and impact resistance, making it less likely to break when the phone is accidentally hit. At the same time, the corrosion resistance of the injection molded base can extend the service life of the product in complex environments.

[0018] 4. Easy installation: The base and cover are molded separately by injection molding and then assembled, or the base and fixing part are molded at the same time by injection molding. Both methods can achieve quick positioning and stable connection of each component, improve assembly efficiency and reduce production costs. Attached Figure Description

[0019] Figure 1 Top view of the assembly structure for the drive shaft of a mobile phone camera; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 This is a schematic diagram of the three-dimensional structure of the cover plate; Figure 4 This is a schematic diagram of the cover plate's planar structure (the flow channel, positioning part, and rear bushing are shown in dashed lines). Figure 5 This is a schematic diagram of the rear axle sleeve. Figure 6 This is a schematic diagram of a base with a riveting structure. Figure 7 This is a schematic diagram of the riveting structure; Figure 8 This is a schematic diagram of the front axle sleeve. Figure 9 This is a summary table of appearance quality test results; Figure 10 This is a summary table of dimensional accuracy test results; Figure 11This is a summary table of mechanical performance test results; Figure 12 This is a summary table of environmental reliability test results.

[0020] In the figure: 1a, front axle sleeve; 1b, rear axle sleeve; 11, transmission part; 12, transmission groove; 2, base plate; 3, base; 4, cover plate; 41, flow channel; 42, fixing part. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] In the following embodiments, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of this invention, it should be understood that terms such as center, longitudinal, transverse, length, width, thickness, upper, lower, front, rear, left, right, vertical, horizontal, top, bottom, inner, outer, clockwise, counterclockwise, etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the description of this invention; therefore, they should not be construed as limiting this invention. Furthermore, terms such as first, second, etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features shown. In the description of this invention, unless otherwise expressly specified and limited, terms such as installation, connection, linking, etc., should be interpreted broadly, and those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Example 1

[0024] This embodiment provides a mobile phone camera drive shaft assembly structure and manufacturing method. It adopts a process route of simultaneously molding the base and cover plate fixing parts in one injection molding, which has high production efficiency and is suitable for mass production.

[0025] Reference Figures 1 to 8 The mobile phone camera drive shaft assembly structure in this embodiment includes a base and a cover plate. The base is made of plastic, specifically injection molded from a mixture of modified PPS and 30% by weight of glass fiber. This material has a heat distortion temperature of not less than 260°C and exhibits excellent heat resistance and dimensional stability. A riveting structure is fixed on the base, including an interference-fit base plate and a front axle sleeve.

[0026] The front axle bushing is made of stainless steel and features a hollow transmission section with a central transmission groove for mating with the drive shaft. The inner wall of the transmission groove is coated with a self-lubricating, wear-resistant coating, a mixture of PTFE and molybdenum disulfide, applied evenly to the inner wall of the transmission groove using a spraying process. The coating thickness is controlled within the range of 0.06–0.09 mm. PTFE provides basic lubrication with a low coefficient of friction, while molybdenum disulfide fills surface pits at the microscopic level, further enhancing wear resistance and load-bearing capacity. The synergistic effect of both significantly reduces the coefficient of friction between the transmission groove and the drive shaft.

[0027] A rear axle sleeve is fixedly mounted on the cover plate. The rear axle sleeve is also made of stainless steel and has a hollow transmission part with a transmission groove at its center. The inner wall of the transmission groove has the same self-lubricating and wear-resistant coating as the front axle sleeve. The cover plate has internal flow channels and also includes a fixing part that is injection-molded and cured within the flow channels. The fixing part and the cover plate body are made of the same material (modified PPS + 30% glass fiber). During injection molding, the molten plastic fills the flow channels and cures, thus integrally fixing the rear axle sleeve to the cover plate. The fixing part wraps around the outer circumference of the rear axle sleeve, forming a secure mechanical lock to prevent the rear axle sleeve from loosening or falling off during use.

[0028] The base and cover plate are fitted together and fixed in place. The fitting method can be conventional, such as snap-fit ​​connection, welding, or screw fastening. After the two are fitted together, a receiving space is formed between the base and the cover plate to accommodate components such as the drive shaft (not shown in the figure). The drive groove of the front axle sleeve and the drive groove of the rear axle sleeve are coaxially arranged to ensure that the drive shaft can rotate or slide smoothly between the front axle sleeve and the rear axle sleeve in the part located in the receiving space.

[0029] To ensure transmission accuracy, the transmission grooves of both the front and rear axle sleeves are machined with high precision. The roundness of the transmission groove is ≤0.005mm, the coaxiality of the transmission groove relative to the outer circle of the transmission part is ≤0.005mm, the straightness error of the transmission groove axis is ≤0.005mm, and the parallelism error of the two end faces of the transmission groove is ≤0.01mm. These precision indicators ensure that the fit clearance of the transmission shaft within the assembly structure is uniform and controlled, preventing wobbling due to excessive clearance and jamming due to insufficient clearance.

[0030] The manufacturing method of this embodiment includes the following steps: The first step involves riveting the front axle sleeve to the base plate, forming a riveted structure. Specifically, the base plate has pre-stamped riveting holes with a diameter of 1.5mm, and the outer diameter of the transmission part of the front axle sleeve is 1.6mm. An annular clearance structure with a height of 0.25mm and a diameter of 1.4mm is provided on the outer bottom of the front axle sleeve, at least 0.3mm from the end face. Using an automated insertion device, the front axle sleeve is forcibly pressed into the riveting holes of the base plate, using an interference fit to rivet the front axle sleeve and base plate together. The annular clearance structure provides space for material deformation during the riveting process, preventing stress concentration and cracking.

[0031] Then, the riveted structure is positioned on the first pre-compression core, and the cover plate is then positioned and installed on the first pre-compression core to form a pre-assembled assembly. The first pre-compression core is set inside the first injection mold. The first pre-compression core has two types of positioning posts for positioning the front and rear axle sleeves, respectively. The diameters of the two positioning posts are precisely matched with the diameters of the transmission grooves of the front and rear axle sleeves, with a clearance of no more than 0.005 mm. During pre-assembly, the rear axle sleeve is first fitted onto the first pre-compression core, then the riveted structure with the front axle sleeve and base plate is fitted onto the first pre-compression core, and finally the cover plate is fitted onto the first pre-compression core. The first pre-compression core passes through the transmission grooves of the front and rear axle sleeves. Simultaneously, the shoulder of the first pre-compression core or the mold mating surface is used to precisely position each component radially and axially, ensuring that each component remains in its predetermined position before injection molding. The first pre-compression core occupies the space of the transmission groove, effectively preventing molten plastic from entering the transmission groove during subsequent injection molding, thus protecting the transmission groove from damage.

[0032] The second step involves placing the pre-assembled components, along with the first pre-compression core, into the first injection mold. After mold closing, the cavity of the first injection mold forms a closed space around the riveting structure and the cover plate. Molten modified PPS and 30% glass fiber mixture is injected into the cavity, with injection pressure, temperature, and other parameters set according to the conventional molding process for this material. The molten plastic flows within the cavity, filling the area around the base plate to form a base. The base covers and fixes the entire riveting structure, firmly uniting the base plate, front axle sleeve, and base into one piece. Simultaneously, the molten plastic fills and solidifies along the flow channels within the cover plate to form a fixing part, which integrally fixes the rear axle sleeve to the cover plate. The base and fixing part are formed simultaneously in a single injection molding process.

[0033] The third step is to open the mold after injection molding, and the base and cover plate will be ejected from the mold. Since the base and cover plate are in the same mold cavity during injection molding, the cover plate needs to be separated from the base after demolding. After separation, the first pre-compression core is removed. At this time, the transmission grooves of the front and rear axle sleeves are kept clean and unobstructed. Finally, the cover plate and base are assembled and fixed to obtain the mobile phone camera drive shaft assembly structure. Example 2

[0034] This embodiment provides another manufacturing method, employing a step-by-step injection molding process. The base and cover plate are independently injection molded in different molds, and then assembled. The advantage of this process is that each component is molded separately, the mold structure is relatively simple, and quality control is easier. The product structure manufactured in this embodiment is the same as in Embodiment 1; therefore, the product structure features will not be described again here. The focus will be on explaining the differences in the manufacturing methods.

[0035] The first step involves riveting the front axle sleeve to the base plate, forming a riveted structure. The riveting process in this step is the same as in Example 1: pre-punched riveting holes are made on the base plate, and the front axle sleeve and base plate are riveted together using an interference fit. Then, the riveted structure is placed into a second injection mold, which contains a second pre-pressed core. The second pre-pressed core is inserted into the drive groove of the front axle sleeve to precisely position the riveted structure radially. After mold closing, molten modified PPS and 30% glass fiber mixture is injected into the cavity of the second injection mold to injection mold a base. The base covers and secures the riveted structure. After demolding, the second pre-pressed core is removed, resulting in a base with the riveted structure.

[0036] The second step involves placing the rear axle sleeve and cover plate into the third injection mold, which contains a third pre-compression core. First, the rear axle sleeve is positioned and installed on the third pre-compression core, using the core to radially position itself through the drive groove of the sleeve. Then, the cover plate is positioned and installed on the third pre-compression core, maintaining the cover plate and rear axle sleeve in a predetermined relative position. After mold closing, molten modified PPS and 30% glass fiber mixture is injected into the cavity of the third injection mold. The molten plastic fills and solidifies along the flow channels within the cover plate, forming a fixing part that integrally secures the rear axle sleeve to the cover plate. After demolding, the third pre-compression core is removed, yielding a cover plate with the rear axle sleeve.

[0037] The third step is to assemble and fix the cover plate with the rear axle sleeve to the base with the riveting structure (i.e., with the front axle sleeve and the base plate), so that the base and the cover plate fit together, and the transmission groove of the front axle sleeve and the transmission groove of the rear axle sleeve are coaxially arranged. After assembly, the mobile phone camera drive shaft assembly structure is obtained.

[0038] To verify the practical effectiveness of the technical solution of this invention, a comprehensive performance test was conducted on the mobile phone camera drive shaft assembly structure manufactured using the above embodiments. The test items covered four dimensions: appearance quality, dimensional accuracy, mechanical properties, and environmental reliability. Specific test results are available (see reference). Figures 9 to 12 )as follows: Appearance quality test: Observe 5 samples. There are no bubbles, shrinkage marks, or color difference on the surface. The inserts are centered and there is no offset. The average coaxiality is 0.0035mm, which meets the design requirements.

[0039] Dimensional accuracy test: Using a micrometer, the measured average inner diameter of the transmission groove is 1.003mm (standard value 1.00±0.005mm), and the measured average outer diameter of the transmission part is 1.602mm (standard value 1.60±0.005mm). The dimensional accuracy is qualified.

[0040] Mechanical property testing: Tensile tests were conducted according to ISO 527-2 standard. The average measured tensile strength was 68.5 MPa (requirement ≥ 60 MPa); elongation at break was 4.2% (requirement ≥ 3.5%); flexural strength was 96.8 MPa (requirement ≥ 90 MPa); and riveting tensile strength was 1385 N (requirement ≥ 1200 N). All mechanical properties met the standards.

[0041] Environmental reliability testing: After being tested at -40℃ for 4 hours and at 85℃ for 4 hours, the samples showed no cracking or deformation, with tensile strength retention rates of 84.4% and 83.1%, respectively. After 1000 hours of humid heat aging at 40℃ / 90%RH, the tensile strength decreased by 23.5%, with no cracking or powdering observed. Fatigue testing (40% load tensile strength, 10...) 6 After several cycles, there was no breakage, and the tensile strength decreased by 10.0%, indicating that the reliability meets the design requirements.

[0042] Test results show that the mobile phone camera drive shaft assembly structure of the present invention meets industry standards and enterprise design requirements in terms of appearance quality, dimensional accuracy, mechanical properties and environmental reliability, and has good comprehensive performance and long-term reliability. Alternative implementation methods

[0043] In the above embodiments, both the front and rear axle bushings are made of stainless steel. Alternatively, provided the strength requirements are met, the front and / or rear axle bushings can also be made of other metals, such as brass, aluminum alloy, or titanium alloy. The specific material can be selected based on cost control requirements and the operating environment. Correspondingly, the self-lubricating and wear-resistant coating can also be made of other low-friction coating materials, such as a nickel-based composite plating containing MoS2 or a DLC (diamond-like carbon) coating.

[0044] In addition to the modified PPS and 30% glass fiber mixture used in the embodiments, the injection molding materials for the base and cover can also be other engineering plastics with sufficient strength and heat resistance, such as LCP (liquid crystal polymer), PA66 (nylon 66) with glass fiber reinforcement, etc.

[0045] The scope of protection of this invention includes, but is not limited to, the above embodiments. The scope of protection of this invention is defined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art fall within the scope of protection of this invention.

Claims

1. A mobile phone camera drive shaft assembly structure, characterized in that, Includes base and cover; The base is made of plastic and has a riveting structure fixed on it. The riveting structure includes an interference-fitted base plate and a front axle sleeve; a rear axle sleeve is fixed on the cover plate. Both the front and rear axle sleeves are made of metal and have hollow transmission parts. The center of each transmission part is provided with a transmission groove for cooperating with the transmission shaft. The inner wall of the transmission groove is provided with a self-lubricating and wear-resistant coating. The transmission groove of the front axle sleeve and the transmission groove of the rear axle sleeve are coaxially arranged.

2. The mobile phone camera drive shaft assembly structure according to claim 1, characterized in that, The self-lubricating wear-resistant coating is a mixture of PTFE and molybdenum disulfide.

3. The mobile phone camera drive shaft assembly structure according to claim 2, characterized in that, The thickness of the hybrid coating is 0.06 to 0.09 mm.

4. The mobile phone camera drive shaft assembly structure according to claim 1, characterized in that, The cover plate has a flow channel inside, and the cover plate also includes a fixing part that is injection molded and cured in the flow channel, and the fixing part integrally fixes the rear axle sleeve to the cover plate.

5. The mobile phone camera drive shaft assembly structure according to claim 4, characterized in that, The injection molding material of both the base and the fixing part is a mixture of modified PPS and 30% glass fiber.

6. The mobile phone camera drive shaft assembly structure according to claim 1, characterized in that, Both the front and rear axle bushings are made of stainless steel.

7. The mobile phone camera drive shaft assembly structure according to claim 1, characterized in that, The roundness of the transmission groove is ≤0.005mm, and the coaxiality of the transmission groove relative to the outer circle of the transmission part is ≤0.005mm; the straightness error of the axis of the transmission groove is ≤0.005mm, and the parallelism error of its two end faces is ≤0.01mm.

8. A method for manufacturing a mobile phone camera drive shaft assembly structure as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Rivet the front axle sleeve to the base plate to form a riveting structure; position the rear axle sleeve and the riveting structure on the first pre-pressing core, and then position and install the cover plate on the first pre-pressing core to form a pre-assembled assembly; S2: The pre-assembled component is placed into the first injection mold, and the base and the fixing part filled in the cover plate flow channel are formed simultaneously by injection molding, wherein the base covers and fixes the riveting structure, and the fixing part fixes the rear bushing to the cover plate. S3: After demolding, separate the cover plate from the base, remove the first pre-pressed core, and then assemble and fix the cover plate and the base to obtain the mobile phone camera drive shaft assembly structure.

9. A method for manufacturing a mobile phone camera drive shaft assembly structure as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: The front axle sleeve is riveted and fixed to the base plate to form a riveting structure; the riveting structure is placed into the second injection mold, and the second pre-pressed core in the second injection mold is used to position the riveting structure, and the base is injection molded to form the base, which covers and fixes the riveting structure. S2: Place the rear axle sleeve and cover plate into the third injection mold. First, position and install the rear axle sleeve on the third pre-compression core of the third injection mold. Then, position and install the cover plate on the third pre-compression core. Inject and mold a fixing part that fills the flow channel of the cover plate. The fixing part fixes the rear axle sleeve to the cover plate. S3: Assemble and fix the cover plate to the base to obtain the mobile phone camera drive shaft assembly structure.

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