Threaded middle pipe and manufacturing method thereof

Abstract

The invention belongs to the technical field of ventilation and fan manufacturing, and discloses a thread-shaped middle pipe and a manufacturing method thereof.The thread-shaped middle pipe comprises a support middle pipe, a first thread structure is arranged on the outer diameter surface of the support middle pipe; a second thread structure matched with the first thread structure is arranged on the surface of an inner hole of an insulating seat of the wire frame; a third thread structure matched with the first thread structure is arranged on the surface of an inner hole of the silicon steel sheet; the second thread structure and the third thread structure jointly form a composite thread joint matched with the outer diameter thread of the stent middle tube; regular thread structures are machined on the outer diameter of the support middle pipe, the inner hole of the coil holder insulating seat and the inner hole of the silicon steel sheet, multi-point mechanical engagement is achieved in a screwing-in assembly mode, high-strength fixation of the stator and the middle pipe can be achieved without depending on close-fitting amount or glue solidification, and the stator and the middle pipe can be firmly fixed. The dependence on glue is greatly reduced by the mechanical locking effect of the thread structure, and the fixing requirement can be met only by dispensing glue locally on the thread matching surface.

Description

Technical Field

[0001] The present invention relates to the technical field of ventilation and fan manufacturing, and in particular to a threaded middle pipe and a manufacturing method thereof. Background Art

[0002] During the assembly process of existing fans, the fixation between the center tube and the stator assembly (including the bobbin insulation seat and silicon steel sheet) mainly relies on the tight fit between the center tube's outer diameter and the silicon steel sheet's inner diameter, and the manual application of glue to assist in fixing. However, this traditional design has the following significant drawbacks:

[0003] The center tube is usually made of plastic material, and its outer diameter is easily affected by factors such as temperature and humidity during processing and use, resulting in dimensional deviations (such as a smaller outer diameter). When the outer diameter of the center tube is smaller than the inner diameter of the silicon steel sheet, the tight fit is insufficient, and the stator is prone to loosening or even falling off. In order to compensate for the dimensional tolerance, a large amount of glue needs to be applied between the center tube and the stator. However, it takes a certain amount of time for the glue to cure, and in actual production, due to operational negligence (such as forgetting to apply glue) or time constraints, the glue is often not completely cured before subsequent assembly (such as buckling the fan blades), which leads to the risk of the stator loosening or falling off. Summary of the Invention

[0004] The main purpose of the present invention is to provide a threaded middle tube and a manufacturing method thereof, aiming to solve the problem that the middle tube is usually made of plastic material, and its outer diameter is easily affected by factors such as temperature and humidity during processing and use, resulting in dimensional deviation. When the outer diameter of the middle tube is smaller than the inner diameter of the silicon steel sheet, the tight fit is insufficient, and the stator is prone to loosening or even falling off. In order to compensate for the dimensional tolerance, a large amount of glue needs to be applied between the middle tube and the stator. However, it takes a certain amount of time for the glue to cure, and in actual production, due to operational negligence or time constraints, the glue is often not completely cured before subsequent assembly is carried out, thereby causing technical problems such as the risk of the stator loosening or falling off.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a threaded middle tube and a manufacturing method thereof, comprising:

[0006] The outer diameter surface of the middle tube of the bracket is provided with a first thread structure;

[0007] The insulating seat of the wire rack has an inner hole surface provided with a second thread structure that matches the first thread structure;

[0008] A silicon steel sheet, the inner hole surface of which is provided with a third thread structure that matches the first thread structure;

[0009] The second thread structure and the third thread structure together form a composite thread channel that matches the outer diameter thread of the tube in the stent.

[0010] Furthermore, the cross-sectional shape of the thread of the first thread structure is a regular geometric shape selected from a triangle, a trapezoid or an arc.

[0011] Furthermore, the pitch range of the first thread structure, the second thread structure and the third thread structure is 0.5-2.0 mm, and the thread depth is 0.3-1.0 mm.

[0012] Furthermore, the first thread structure on the outer diameter of the middle tube of the stent is manufactured by a turning or rolling forming process.

[0013] Furthermore, the matching clearance between the composite thread channel and the first thread structure of the outer diameter of the tube in the stent is 0.05-0.15 mm.

[0014] Furthermore, an auxiliary fixing adhesive layer is provided between the mating surfaces of the composite threaded channel and the first threaded structure, and the thickness of the adhesive layer does not exceed 0.1 mm.

[0015] The present invention also protects a method for manufacturing a threaded middle pipe, comprising the following steps:

[0016] (a) forming a first thread structure on the outer diameter surface of the stent tube;

[0017] (b) machining the inner hole surface of the wire rack insulation seat to form a second thread structure;

[0018] (c) machining the inner hole surface of the silicon steel sheet to form a third thread structure;

[0019] (d) Screw the stator assembly with the second thread structure and the third thread structure onto the first thread structure of the tube in the bracket by screwing in the assembly method.

[0020] Furthermore, the thread processing in step (a) is performed using a CNC lathe with a cutting speed of 800-1200 rpm and a feed rate of 0.1-0.3 mm / revolution.

[0021] Furthermore, in step (d), an automatic screw-in assembly device is used, and the screw-in torque applied is 0.5-2.0 N·m 2 .

[0022] Furthermore, after the assembly in step (d) is completed, a local glue treatment is performed on the threaded mating parts, and the amount of glue used does not exceed 0.05 ml / cm.

[0023] Beneficial effects:

[0024] 1. This invention incorporates regular threaded structures on the outer diameter of the stent's center tube, the inner bore of the bobbin insulation seat, and the inner bore of the silicon steel sheet, achieving multi-point mechanical engagement through screw-in assembly. This eliminates the need for tight fit or glue curing, ensuring a high-strength fixation between the stator and the center tube. This effectively prevents the stator from loosening or falling off, even during drop tests, significantly improving stator stability.

[0025] 2. The mechanical locking effect of the thread structure significantly reduces the reliance on glue. Only localized glue application on the threaded mating surface is required to secure the parts. Compared to traditional full-coat glue processes, this reduces glue usage and curing time. There is no need to wait for the glue to cure, shortening production cycles.

[0026] 3. The present invention can compensate for the dimensional deviation between the outer diameter of the middle tube and the inner diameter of the silicon steel sheet through the spiral engagement characteristics of the thread structure, avoid assembly defects caused by lax dimensional control, and reduce the production defect rate to below 0.5%.

[0027] 3. The present invention uses mechanical fixation of the threaded structure. The stator can withstand continuous operation at 2000 rpm for 72 hours without displacement during fan operation, and pass the 1.5m height free drop test 10 times without falling off, greatly improving product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is a schematic diagram of a cross-sectional structure of a threaded middle tube according to an embodiment of the present invention;

[0029] Figure 2 The threaded middle tube of one embodiment of the present invention is Figure 1 A in the middle is an enlarged structural diagram;

[0030] Figure 3 This is a schematic diagram of the structure of a support middle tube with a threaded middle tube according to one embodiment of the present invention;

[0031] Figure 4 This is a schematic structural diagram of an insulating seat of a threaded middle tube according to an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the silicon steel sheet structure of the threaded middle tube according to one embodiment of the present invention.

[0033] in:

[0034] 16- bracket middle tube; 1601- first thread structure; 6- insulation seat; 601- second thread structure; 11- silicon steel sheet; 110- third thread structure.

[0035] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0036] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections, direct connections, or indirect connections through an intermediate medium; they may refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0039] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0040] Reference Figure 1-Figure 5 One embodiment of the present invention provides a threaded middle tube and a manufacturing method thereof, comprising:

[0041] The outer diameter surface of the bracket middle tube 16 is provided with a first thread structure 1601;

[0042] The insulating seat 6 of the wire rack has an inner hole surface provided with a second thread structure 601 that matches the first thread structure 1601;

[0043] The silicon steel sheet 11 has a third thread structure 110 on its inner hole surface that matches the first thread structure 1601;

[0044] The second thread structure 601 and the third thread structure 110 together form a composite thread channel that matches the outer diameter thread of the stent middle tube 16. The first thread structure 1601 on the outer diameter of the stent middle tube 16 is manufactured by turning or rolling forming.

[0045] In this embodiment, the bracket middle tube 16 is made of a high-heat-resistant engineering plastic, such as polyamide PA66 or polyethylene terephthalate PBT, to meet the mechanical strength and temperature resistance requirements during fan operation. The first thread structure 1601 is surface treated by rolling and then polishing to reduce the friction coefficient and facilitate screwing and assembly.

[0046] The second thread structure 601 within the insulator seat 6 matches the thread of the bracket's central tube 16, adopting the same triangular cross-section as the central tube, with a pitch of 1.0mm and a depth of 0.5mm. CNC precision machining ensures the inner hole surface roughness is ≤ Ra 1.6μm to avoid jamming during assembly.

[0047] The third thread structure 110 within the inner hole of the silicon steel sheet 11 is identical to the thread structure of the central pipe. Made of cold-rolled steel, the threads are formed via EDM or laser engraving to ensure strong engagement with the plastic thread. The inner surface of the threads is coated with epoxy resin for enhanced wear and corrosion resistance.

[0048] The glue was evenly dispensed on the threaded mating surface using a fully automatic glue dispenser with an accuracy of ±0.01ml, with a dosage of ≤0.05ml / cm. The glue was cured in an 80°C oven for 30 minutes to ensure rapid hardening of the glue layer.

[0049] Optionally, the cross-sectional shape of the first thread structure 1601 is a regular geometric shape selected from a triangle, a trapezoid or an arc. The pitch range of the first thread structure 1601, the second thread structure 601 and the third thread structure 110 are all 0.5-2.0 mm, and the thread depth is 0.3-1.0 mm.

[0050] It should be noted that the cross-sectional shape of the first thread structure 1601 is preferably a triangular thread, as it has a large contact area and strong self-locking properties, making it suitable for plastic molding. The pitch is set to 1.0mm and the thread depth is 0.5mm to ensure a tight engagement with the threads of the insulating seat 6 and the silicon steel sheet 11.

[0051] Optionally, the clearance between the composite thread channel and the first thread structure 1601 of the outer diameter of the bracket middle tube 16 is 0.05-0.15 mm. An auxiliary fixing adhesive layer is provided between the mating surfaces of the composite thread channel and the first thread structure 1601, and the thickness of the adhesive layer does not exceed 0.1 mm.

[0052] It should be noted that the internal threads of the insulating seat 6 and the silicon steel sheet 11 are designed with a stepped distribution to form a continuous composite thread channel, which achieves multi-point contact with the external threads of the bracket middle tube 16, improving the fixation stability. The clearance between the composite thread channel and the middle tube thread is controlled at 0.1mm to ensure smooth insertion and prevent jamming. Local glue, such as acrylic glue, is applied between the threaded mating surfaces with a glue layer thickness of ≤0.1mm. This is only used for supplementary fixation and does not rely on the traditional full glue coating process.

[0053] In one embodiment, a method for manufacturing a threaded middle tube includes the following steps:

[0054] (a) A first thread structure 1601 is formed on the outer diameter surface of the stent tube 16;

[0055] The 16 threads on the bracket's center tube are machined using a four-axis CNC lathe, such as a FANUC Series 30i, equipped with carbide tools. The preferred cutting speed is 1000 rpm, the preferred feed rate is 0.2 mm / rev, and the preferred depth of cut is 0.3 mm.

[0056] (b) The inner surface of the wire rack insulating seat 6 is processed to form a second thread structure 601;

[0057] The internal thread of the insulating seat 6 is processed using a deep-hole boring process with a micro-tap, and the diameter is gradually expanded from φ3mm to φ10mm. The preferred boring speed is 800rpm, the feed rate is 0.15mm / rev, and the internal hole diameter tolerance is ±0.02mm to ensure compatibility with the medium pipe thread.

[0058] (c) forming a third thread structure 110 on the inner hole surface of the silicon steel sheet 11;

[0059] The internal thread of the silicon steel sheet 11 is processed by laser engraving with a power of 300W and a pulse frequency of 20kHz, avoiding the material stress and deformation caused by traditional machining. The laser scanning speed is 1500mm / min and the focus offset is -0.1mm.

[0060] (d) The stator assembly with the second thread structure 601 and the third thread structure 110 is screwed onto the first thread structure 1601 of the bracket middle tube 16 by screwing in the assembly method.

[0061] The screw-in assembly and dispensing use a six-axis robot arm with a servo motor to drive the fixture, and the assembly torque is set to 1.5N·m 2 .

[0062] Assembly process: Insert the stator assembly (insulating seat 6 + silicon steel sheet 11) into the bracket's center tube 16. Use the fixture to rotate the stator assembly so that the composite thread channel engages with the center tube thread. The screw-in angle is controlled: rotate 90°-120°, ensuring the thread engagement length is ≥15mm.

[0063] The thread processing in step (a) is performed by a CNC lathe with a cutting speed of 800-1200 rpm and a feed rate of 0.1-0.3 mm / revolution.

[0064] In step (d), an automatic screw-in assembly device is used, and the screw-in torque applied is 0.5-2.0 N·m 2 .

[0065] After the assembly in step (d) is completed, local glue treatment is performed on the threaded mating parts, and the amount of glue used does not exceed 0.05 ml / cm.

[0066] Description: During assembly, the composite thread channel of the stator assembly is screwed into the external thread of the bracket middle tube 16. The composite thread channel is a cooperative thread of the insulating seat 6 and the silicon steel sheet 11. The distributed stress transmission of the thread bevel converts the traditional radial compressive stress into axial shear stress, and the elastic deformation energy storage of the POM material forms a continuous clamping force. During operation, the thread pair uses the torque self-locking effect (reverse torque enhances preload) and the vibration energy dissipation mechanism (micro damping of 0.05-0.15mm gap) combined with the thermal expansion difference. Differential compensation (thread lead absorbs temperature rise deformation) achieves dynamic stability; during drop impact, the plastic deformation of the thread crest and the dislocation sliding constitute two-stage energy absorption, combined with magnetic assisted positioning and lubricating oil capillary penetration (2-5μm oil film) to form long-term impact protection; during long-term operation, the UV adhesive layer creeps to fill the gap, and cooperates with the magnetic pull (15-20N) to maintain adaptive fixation, ultimately solving the loosening and falling problems of traditional interference fits, achieving a significant improvement in drop displacement of less than 0.1mm and assembly defect rate of less than 0.5%.

[0067] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A threaded middle tube, characterized in that: include: The outer diameter surface of the support middle tube (16) is provided with a first thread structure (1601); The insulating seat (6) of the wire rack has an inner hole surface provided with a second thread structure (601) that matches the first thread structure (1601); A silicon steel sheet (11), the inner hole surface of which is provided with a third thread structure (110) that matches the first thread structure (1601); The second thread structure (601) and the third thread structure (110) together form a composite thread channel that matches the outer diameter thread of the bracket middle tube (16).

2. The threaded middle tube according to claim 1, characterized in that: The cross-sectional shape of the thread of the first thread structure (1601) is a regular geometric shape selected from a triangle, a trapezoid or an arc.

3. The threaded middle tube according to claim 1, characterized in that: The pitch range of the first thread structure (1601), the second thread structure (601) and the third thread structure (110) are all 0.5-2.0 mm, and the thread depth is 0.3-1.0 mm.

4. The threaded middle tube according to claim 1, characterized in that: The first thread structure (1601) on the outer diameter of the bracket middle tube (16) is manufactured by a turning or rolling forming process.

5. The threaded middle tube according to claim 1, characterized in that: The matching clearance between the composite thread channel and the first thread structure (1601) of the outer diameter of the bracket middle tube (16) is 0.05-0.15 mm.

6. The threaded middle tube according to claim 1, characterized in that: An adhesive layer for auxiliary fixation is provided between the mating surfaces of the composite thread channel and the first thread structure (1601), and the thickness of the adhesive layer does not exceed 0.1 mm.

7. A method for manufacturing a threaded middle pipe according to any one of claims 1 to 6, characterized in that The following steps are involved: (a) forming a first thread structure (1601) on the outer diameter surface of the stent middle tube (16); (b) machining the inner hole surface of the wire rack insulation seat (6) to form a second thread structure (601); (c) machining the inner hole surface of the silicon steel sheet (11) to form a third thread structure (110); (d) The stator assembly with the second thread structure (601) and the third thread structure (110) is screwed onto the first thread structure (1601) of the bracket middle tube (16) by screwing in the assembly method.

8. The method for manufacturing a threaded middle pipe according to claim 7, characterized in that: The thread processing in step (a) is performed by a CNC lathe with a cutting speed of 800-1200 rpm and a feed rate of 0.1-0.3 mm / revolution.

9. The method for manufacturing a threaded middle pipe according to claim 7, characterized in that: In step (d), an automatic screw-in assembly device is used, and the screw-in torque applied is 0.5-2.0 N·m 2 .

10. The method for manufacturing a threaded middle pipe according to claim 7, wherein: After the assembly in step (d) is completed, local glue treatment is performed on the threaded mating parts, and the amount of glue used does not exceed 0.05 ml / cm.

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