Threaded middle pipe

Abstract

The utility model belongs to the technical field of ventilation and fan manufacturing, and discloses a thread-shaped middle pipe which comprises a support middle pipe, a first thread structure and a second thread structure. 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 processed on the outer diameter of the support middle tube, the inner hole of the coil holder insulating seat and the inner hole of the silicon steel sheet, multi-point mechanical occlusion is realized in a screwing-in assembly mode, and high-strength fixation of the stator and the middle tube can be realized without depending on close-fitting amount or glue solidification. 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] This utility model relates to the field of ventilation and fan manufacturing technology, and in particular to a threaded central tube. Background Technology

[0002] In existing fan assembly processes, the fixing of the center tube and stator assembly (including the wire frame insulation base and silicon steel sheet) mainly relies on the tight fit between the outer diameter of the center tube and the inner diameter of the silicon steel sheet, as well as 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, and its outer diameter is easily affected by factors such as temperature and humidity during processing and use, leading to dimensional deviations (such as an outer diameter that is too small). When the outer diameter of the center tube is smaller than the inner diameter of the silicon steel sheet, the tightness is insufficient, and the stator is prone to loosening or even falling off. To compensate for dimensional tolerances, a large amount of glue needs to be applied between the center tube and the stator. However, the glue requires a certain amount of time to cure, and in actual production, due to operational negligence (such as forgetting to apply glue) or time constraints, subsequent assembly (such as attaching fan blades) is often carried out before the glue is fully cured, thus causing the risk of the stator loosening or falling off. Utility Model Content

[0004] The main objective of this invention is to provide a threaded-shaped center tube, addressing the issue that center tubes, typically made of plastic, are susceptible to dimensional deviations due to temperature and humidity fluctuations during processing and use. When the outer diameter of the center tube is smaller than the inner diameter of the silicon steel sheet, insufficient tightness leads to stator loosening or even detachment. To compensate for dimensional tolerances, a large amount of adhesive is applied between the center tube and the stator. However, adhesive requires curing time, and in actual production, operational negligence or time constraints often result in incomplete curing of the adhesive before subsequent assembly, thus increasing the risk of stator loosening or detachment.

[0005] To achieve the aforementioned objectives of this utility model, the first aspect of this utility model provides a threaded tube, comprising:

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

[0007] The insulating base of the wire frame has a second thread structure on its inner surface that mates with the first thread structure;

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

[0009] The second and third threaded structures together form a composite threaded channel that mates with the outer diameter thread of the tube in the support.

[0010] Furthermore, the thread profile of the first thread structure is a regular geometric shape selected from triangles, trapezoids, or arcs.

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

[0012] Furthermore, the first thread structure of the outer diameter of the tube in the bracket is manufactured by turning or roll forming.

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

[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] Beneficial effects:

[0016] 1. This utility model achieves multi-point mechanical engagement by machining regular thread structures on the outer diameter of the bracket tube, the inner hole of the wire frame insulation seat, and the inner hole of the silicon steel sheet, and by screwing them in. It achieves high-strength fixation between the stator and the tube without relying on tightness or adhesive curing, effectively preventing the stator from loosening or falling off even during drop tests, thus significantly improving stator stability.

[0017] 2. This utility model significantly reduces reliance on adhesive through the mechanical locking effect of the threaded structure. Only localized application of adhesive to the threaded mating surfaces is required to meet the fixing needs. Compared to traditional full-coat adhesive processes, this reduces adhesive usage and curing time, and eliminates the need to wait for the adhesive to cure, thus shortening the production cycle.

[0018] 3. This utility model can compensate for the dimensional deviation between the outer diameter of the tube and the inner diameter of the silicon steel sheet through the helical engagement characteristic of the threaded structure, avoid assembly defects caused by poor dimensional control, and reduce the production defect rate to below 0.5%.

[0019] 3. This utility model uses a threaded mechanical fixing structure, which allows the stator to withstand continuous operation at 2000rpm for 72 hours without displacement during fan operation. It also passed 10 free drop tests from a height of 1.5m without falling off, greatly improving product reliability. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of a threaded tube according to an embodiment of the present invention;

[0021] Figure 2 This is a threaded tube according to an embodiment of the present invention. Figure 1 Enlarged structural diagram at point A in the middle;

[0022] Figure 3This is a schematic diagram of the support tube structure of a threaded tube according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the insulating seat structure of a threaded tube according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the silicon steel sheet structure of a threaded tube according to an embodiment of the present invention.

[0025] in:

[0026] 16-Support tube; 1601-First threaded structure; 6-Insulating seat; 601-Second threaded structure; 11-Silicon steel sheet; 110-Third threaded structure.

[0027] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0029] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly and specifically defined.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0032] Reference Figures 1-5 An embodiment of this utility model provides a threaded tube, comprising:

[0033] The bracket tube 16 has a first thread structure 1601 on its outer diameter surface;

[0034] The insulating base 6 of the wire frame has a second thread structure 601 on its inner surface that mates with the first thread structure 1601;

[0035] Silicon steel sheet 11, the inner surface of which is provided with a third thread structure 110 that mates with the first thread structure 1601;

[0036] The second thread structure 601 and the third thread structure 110 together form a composite threaded channel that mates with the outer diameter thread of the bracket tube 16. The first thread structure 1601 of the outer diameter of the bracket tube 16 is manufactured by turning or roll forming.

[0037] In this embodiment, the support tube 16 is made of high heat-resistant engineering plastic, such as polyamide PA66 or polyethylene terephthalate PBT, to meet the mechanical strength and temperature resistance requirements of the fan during operation. The first thread structure 1601 undergoes surface treatment: after roll forming, it is polished to reduce the coefficient of friction and facilitate screw-in assembly.

[0038] The second thread structure 601 in the inner hole of the insulating seat 6 is threadedly matched with the middle tube 16 of the bracket, adopting the same triangular cross-sectional shape as the middle tube, with a thread pitch of 1.0 mm and a depth of 0.5 mm. Precision CNC machining is used to ensure that the surface roughness of the inner hole is ≤ Ra 1.6 μm to avoid jamming during assembly.

[0039] The third thread structure 110 inside the silicon steel sheet 11 is completely consistent with the thread structure of the central tube. It is made of cold-rolled steel and the thread is formed by electrical discharge machining (EDM) or laser engraving to ensure the engagement strength with the plastic thread. The inner side of the thread is coated with epoxy resin to enhance wear resistance and corrosion resistance.

[0040] The adhesive was applied using a fully automatic dispensing machine with an accuracy of ±0.01ml, dispensing evenly onto the threaded mating surfaces at a rate ≤0.05ml / cm. The adhesive was then cured in an 80℃ oven for 30 minutes to ensure rapid hardening.

[0041] Optionally, the thread profile of the first thread structure 1601 is a regular geometric shape selected from triangle, trapezoid, or arc. The pitch range of the first thread structure 1601, the second thread structure 601, and the third thread structure 110 is 0.5-2.0 mm, and the thread depth is 0.3-1.0 mm.

[0042] It should be noted that the cross-sectional shape of the first thread structure 1601 is preferably a triangular thread, due to its large contact area and strong self-locking properties, making it suitable for molding plastic materials. The pitch is set to 1.0 mm, and the thread depth is 0.5 mm to ensure tight engagement with the threads of the insulating seat 6 and the silicon steel sheet 11.

[0043] Optionally, the fitting clearance between the composite threaded channel and the first threaded structure 1601 on the outer diameter of the bracket tube 16 is 0.05-0.15 mm. An auxiliary fixing adhesive layer is provided between the mating surfaces of the composite threaded channel and the first threaded structure 1601, and the thickness of the adhesive layer does not exceed 0.1 mm.

[0044] It should be noted that the internal threads of the insulating base 6 and the silicon steel sheet 11 are designed in a stepped manner to form a continuous composite thread channel, achieving multi-point contact with the external thread of the bracket tube 16, thus improving the fixing stability. The mating clearance between the composite thread channel and the tube thread is controlled at 0.1mm to ensure no shaking or jamming during screwing. Local application of adhesive, such as acrylic glue, with a layer thickness ≤0.1mm, is used between the thread mating surfaces for supplementary fixing only, and does not rely on the traditional full-coat adhesive process.

[0045] In one embodiment, a method for manufacturing a threaded tube includes the following steps:

[0046] (a) A first thread structure 1601 is formed on the outer diameter surface of the tube 16 in the support;

[0047] The 16mm thread on the bracket tube is 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 / revolution; and the preferred depth of cut is 0.3 mm.

[0048] (b) A second thread structure 601 is formed by machining the inner surface of the wire frame insulating base 6;

[0049] The internal thread of the insulating seat 6 is machined using deep hole boring technology, with a miniature tap, and the diameter is gradually expanded from φ3mm to φ10mm. The boring speed is preferably 800rpm; the feed rate is 0.15mm / revolution; and the internal diameter tolerance is ±0.02mm to ensure matching with the thread of the central pipe.

[0050] (c) A third thread structure 110 is formed on the inner surface of the silicon steel sheet 11;

[0051] The internal thread of the silicon steel sheet (11mm diameter) is machined using laser engraving with a power of 300W and a pulse frequency of 20kHz, avoiding material stress deformation caused by traditional machining. The laser scanning speed is 1500mm / min, and the focus offset is -0.1mm.

[0052] (d) The stator assembly with the second threaded structure 601 and the third threaded structure 110 is screwed onto the first threaded structure 1601 of the bracket tube 16 by a screw-in assembly method.

[0053] The screw-in assembly and dispensing are performed using a six-axis robotic arm paired with a servo motor-driven fixture, with the assembly torque set at 1.5 N·m. 2 .

[0054] Assembly process: Insert the stator assembly (insulating seat 6 + silicon steel sheet 11) into the bracket tube 16. Rotate the stator assembly using a clamp to engage the composite threaded channel with the tube thread. Control the screw-in angle: rotate 90°-120° to ensure the thread engagement length is ≥15mm.

[0055] The thread machining 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.

[0056] In step (d), an automatic screw-in assembly device is used, and the applied screw-in torque is 0.5-2.0 N·m. 2 .

[0057] After the assembly in step (d) is completed, apply adhesive to the threaded mating parts locally, with the amount of adhesive not exceeding 0.05 ml / cm.

[0058] Note: During assembly, the composite threaded channel of the stator assembly is screwed into the external thread of the bracket tube 16. The composite threaded channel is the cooperative thread of the insulating seat 6 and the silicon steel sheet 11. Through the distributed stress transfer of the threaded inclined surface, the traditional radial compressive stress is converted into axial shear stress. Combined with the elastic deformation energy storage of the POM material, a continuous clamping force is formed. During operation, the threaded pair utilizes the torque self-locking effect (reverse torque enhances preload) and the vibration energy dissipation mechanism (micro-damping of the 0.05-0.15mm gap), combined with the thermal expansion difference. Differential compensation (thread lead absorbs temperature rise deformation) to achieve dynamic stability; during drop impact, the plastic deformation of the thread crest and the misalignment sliding constitute two-stage energy absorption, which, together with magnetic assisted positioning and capillary penetration of lubricating oil (2-5μm oil film), forms long-term impact protection; during long-term operation, the UV adhesive layer creep fills the gap, and together with the magnetic pull force (15-20N), it maintains adaptive fixation, ultimately solving the loosening and falling-off problem of traditional interference fits, and achieving a significant improvement of drop displacement <0.1mm and assembly defect rate <0.5%.

[0059] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the content of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. A middle pipe of a screw shape, characterized by, include: The support tube (16) has a first thread structure (1601) on its outer diameter surface; The insulating base (6) of the wire frame has a second thread structure (601) on its inner hole surface that mates with the first thread structure (1601); Silicon steel sheet (11), the inner surface of which is provided with a third thread structure (110) that cooperates with the first thread structure (1601); The second thread structure (601) and the third thread structure (110) together form a composite threaded channel that mates with the outer diameter thread of the support tube (16).

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

3. The threaded 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) is 0.5-2.0mm, and the thread depth is 0.3-1.0mm.

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

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

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

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