Method for designing number of convex teeth of air-blowing optical cable and air-blowing optical cable

Abstract

The invention provides a method for designing the number of convex teeth of an air-blowing optical cable, the air-blowing optical cable comprises a cable core and an outer sheath, the outer sheath comprises a sheath body and a plurality of convex teeth surrounding the sheath body and arranged in an array, and the air-blowing optical cable is laid in an air-blowing pipeline. According to the distance from the axis of the air-blowing optical cable to the end parts of the convex teeth, the distance from the axis of the air-blowing optical cable to the root parts of the convex teeth, the radius of the air-blowing pipeline, the difference value between the convex tooth farthest in contact with the air-blowing pipeline and the convex tooth of which the middle part is in contact with the air-blowing pipeline, and the distance from the convex tooth farthest in contact with the air-blowing pipeline to the air-blowing pipeline along the contact direction, the air-blowing pipeline is determined; and calculating the number range of the convex teeth according to the curvature radius of the convex teeth and the maximum half-width of contact between the convex teeth of which the middle parts are in contact with the air-blowing pipeline and the air-blowing pipeline. According to the method for designing the number of the convex teeth of the air-blowing optical cable and the air-blowing optical cable, the range of the number of the convex teeth can be obtained through calculation, the test verification step can be omitted, the test cost is saved, the verification process is omitted, and the production period is shortened.

Description

Technical Field

[0001] The invention relates to a method for designing the number of convex teeth of an air-blown optical cable and the air-blown optical cable. Background Art

[0002] Air-blown optical cables are widely used in the construction of modern communication networks because they can be quickly deployed in urban underground pipe networks, long-distance pipelines, and complex terrains by combining the blowing force of compressed air with the thrust of the transmission device. In order to solve the problem of friction damage between the optical cable and the pipe wall during high-speed air blowing, traditional designs usually set air guide grooves or elastic protrusions on the outer surface of the optical cable. This structural design can not only reduce the contact pressure by guiding the air flow, but also use elastic deformation to buffer local stress. At the same time, it has multiple functions such as reducing the contact area, optimizing the cable blowing efficiency, and protecting the optical cable body. It is worth noting that the parameter design of these guide structures needs to comprehensively consider multiple factors such as the elastic modulus of the material, the roughness of the inner wall of the pipe, the air pressure of the cable blowing, etc. Their performance directly affects the construction efficiency and the service life of the optical cable.

[0003] However, in existing technologies, the number and distribution of protrusions rely heavily on the designer's experience and judgment, and are typically verified using a "design first, test later" model. Specifically, designers need to preliminarily determine the protrusion parameters based on empirical formulas, followed by mold fabrication, sample trial production, and air-blowing simulation testing. If the test results are unsatisfactory, the parameters need to be readjusted and the above process repeated. This traditional development model has significant flaws: first, the parameter selection lacks theoretical support, which can easily lead to a mismatch between the flow-guiding structure and the actual working conditions; second, from design to verification, multiple steps must be taken into account, including mold making, trial production, and testing. A single iteration cycle can take several months, involving high equipment and mold costs and human resources investment; finally, existing designs only consider the air-blown optical cable itself, without considering the accompanying air-blown ducting. This R&D model will significantly increase the risk of technology transfer and market competition.

[0004] In view of this, it is necessary to improve the existing method for designing the number of protruding teeth of air-blown optical cables to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide a method for designing the number of protruding teeth of an air-blown optical cable, so as to solve the problem that the existing protruding design needs to be verified through experiments to verify the air-blowing effect.

[0006] To achieve the above object, the present invention provides a method for designing the number of convex teeth of an air-blown optical cable, wherein the air-blown optical cable comprises a cable core and an outer sheath, wherein the outer sheath comprises a sheath body and a plurality of convex teeth arranged in an array around the sheath body, and the air-blown optical cable is used for laying in an air-blown pipe, and the number of teeth of the outer sheath along the axial section is N , N is an integer and satisfies N≥ N min , ,in , is half of the angle between two adjacent convex teeth. R 齿尖 It is the distance from the axis of the air-blown optical cable to the end of the convex tooth. R 齿根 It is the distance from the axis of the air-blown cable to the root of the convex teeth. R 管 is the radius of the air blowing pipe.

[0007] As a further improvement of the present invention, the number of teeth N satisfy N ≤ N max ,in ,in N 间隔 is the difference between the convex tooth that contacts the air blowing pipe the farthest and the convex tooth that contacts the air blowing pipe in the middle. The distance between the convex tooth that is farthest in contact with the air blowing pipe and the air blowing pipe along the contact direction, Equal to the deformation of the convex teeth in contact with the air blowing pipe in the middle , , R 凸 is the curvature radius of the convex tooth, b It is the maximum half-width of the contact between the convex teeth in the middle that contacts the air blowing pipe and the air blowing pipe.

[0008] As a further improvement of the present invention, b The calculation formula is as follows: ,in F / L is the contact force per unit length, F is gravity, L is the length of the air-blown cable, E * is the equivalent elastic modulus, R * is the relative radius of curvature.

[0009] As a further improvement of the present invention, E * The calculation formula is as follows: ,in E 凸 is the Young's modulus of the convex tooth, v 凸 is the Poisson's ratio of the convex tooth, E 管 is the Young's modulus of the air blowing pipe, v 管 is the Poisson's ratio of the air blowing pipe.

[0010] As a further improvement of the present invention, the material of the convex teeth and the sheath body is the same, that is, HDPE high-density polyethylene. E 凸 500-1500MPa, v 凸 It is 0.35-0.45.

[0011] As a further improvement of the present invention, R * The calculation formula is as follows: ,in R 凸 is the curvature radius of the convex tooth, R 管 is the curvature radius of the air blowing pipe.

[0012] As a further improvement of the present invention, N 间隔 =3.

[0013] As a further improvement of the present invention, the tooth height , H : R 齿根 It is 1:40~1:20.

[0014] The present invention also provides an air-blown optical cable, which includes a cable core and an outer sheath. The outer sheath includes a sheath body and a plurality of convex teeth arranged in an array around the sheath body. The number range of the convex teeth is obtained by the above-mentioned method for designing the number of convex teeth of the air-blown optical cable.

[0015] The beneficial effects of the present invention are as follows: the method for designing the number of convex teeth of an air-blown optical cable and the air-blown optical cable of the present invention can obtain the range of the number of convex teeth by calculation, which can omit the test verification step, save the test cost, omit the verification process, and shorten the production cycle. The air-blown optical cable obtained by this method can be quickly put into production and use, thereby improving the competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 Schematic diagram of the air-blown optical cable of the present invention being laid in an air-blown duct; Figure 2 Schematic diagram of the contact between the multiple protruding teeth of the air-blown optical cable of the present invention and the air-blowing pipe; Figure 3 Schematic diagram of a convex tooth of the air-blown optical cable according to the present invention in contact with an air-blowing pipe; Figure 4 Schematic diagram of a convex tooth of the air-blown optical cable of the present invention in contact with the air-blowing pipe and deformed; Figure 5 It is a partially enlarged schematic diagram of the contact between the air-blown optical cable, multiple protruding teeth and the air-blowing pipe of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] like Figures 1 to 5 As shown, the air-blown optical cable of the present invention includes a cable core and an outer sheath, the outer sheath includes a sheath body and a plurality of convex teeth arranged in an array surrounding the sheath body, the air-blown optical cable is used to be laid in an air-blown pipe, and the number range of the convex teeth is obtained by the convex tooth number design method of the air-blown optical cable of the present invention.

[0021] like Figure 1 As shown, in this embodiment, the number of teeth of the outer sheath along the axial section is N , and the convex teeth are arranged in a circular array around the outer sheath, and the distance between two adjacent convex teeth is equal. N is an integer and satisfiesN min ≤ N ≤ N max .

[0022] ,in , is half of the angle between two adjacent convex teeth. R 齿尖 It is the distance from the axis of the air-blown optical cable to the end of the convex tooth. R 齿根 It is the distance from the axis of the air-blown cable to the root of the convex teeth. R tube is the radius of the air blowing pipe. N The value is close to N min , it means that the convex teeth are sparse.

[0023] calculate The formula for obtaining is as follows: Figure 1 , taking the extreme case, in this state, two adjacent protruding teeth are in contact with the air blowing pipe, and the sheath body between the two protruding teeth is in contact with the air blowing pipe, and the following formula is satisfied: ; ,in It is half of the angle between the axis of the air blowing pipe and the two convex teeth in contact with the air blowing pipe, from which it is deduced that .if N Less than N min , it will cause the convex teeth to be too sparse, and the sheath body will contact the air blowing pipe during the air blowing process, which will at least bring the following disadvantages: (1) the sheath body contacts the air blowing pipe, and the convex teeth cannot play a supporting role; (2) the air circulation gap between the outer sheath and the air blowing pipe is reduced; (3) the contact area between the outer sheath and the air blowing pipe is too large, resulting in increased friction; (4) the sheath body directly contacts the pipe, causing wear and tear, which affects the service life of the air-blown optical cable.

[0024] If calculated N min If it is not an integer, N In this embodiment, N Design is greater than N min , so that during the laying process of the air-blown optical cable, the sheath body will not come into contact with the air-blowing pipe, thereby improving the laying efficiency.

[0025] In addition, in this embodiment, the tooth height , H : R 齿根1:40~1:20. Under this design, as long as N min ≤ N , the laying effect of air-blown optical cable can be fully guaranteed.

[0026] The test in this embodiment is an air blowing test, which involves laying an air-blown optical cable in a 1500m long air blowing pipe at a blowing speed of 0 to 60m / min. If the laying can be completed within 50 minutes, it meets the requirements and the test result is a success. If the air blowing time exceeds 50 minutes, it does not meet the requirements and the test result is a failure. The test results for the minimum number of teeth are as follows:

[0027] From the above test data, it can be seen that when the number of teeth is designed N Greater than the calculated number of teeth N min The results of the air blowing test of the embodiment are all successful, and the number of designed teeth is N Less than the calculated number of teeth N min The air blowing test results of the embodiments are all failures.

[0028] like Figures 2 to 5 As shown, ,in N 间隔 is the difference between the convex tooth that contacts the air blowing pipe the farthest and the convex tooth that contacts the air blowing pipe in the middle. The distance between the convex tooth that is farthest in contact with the air blowing pipe and the air blowing pipe along the contact direction, Equal to the deformation of the convex teeth in contact with the air blowing pipe in the middle , , R 凸 is the curvature radius of the convex tooth, b It is the maximum half-width of the contact between the convex teeth in the middle that contacts the air blowing pipe and the air blowing pipe.

[0029] Maximum number of teeth N max The main consideration is the number of contacts between the convex teeth and the air blowing pipe. If the convex teeth are too dense, it may cause excessive contact between the convex teeth and the air blowing pipe, thereby increasing the contact area and increasing friction.

[0030] If it is verified through the test that six or seven convex teeth are in contact with the air blowing pipe, the air blowing effect is poor at this time, then N 间隔 3; Four or five convex teeth are in contact with the blowing pipe, and the air blowing effect is poor. N 间隔2, that is, the number of teeth that affect the air blowing effect needs to be determined through experiments N 摩擦 , or ,See N 摩擦 The parity of N 摩擦 For an even number, the latter applies N 摩擦 For odd numbers, in this embodiment, N 摩擦 Give an example for odd numbers.

[0031] In this embodiment, N 间隔 =3. Multiple tests have shown that when the number of convex teeth in contact with the air blowing pipe is 7 or more, the air blowing effect is extremely poor.

[0032] When a convex tooth of the air-blown optical cable just contacts the air-blown pipe, the axis connection direction of the air-blown optical cable and the air-blown pipe is set to the h direction. At this time, the convex tooth has not been deformed and the distance between it and the contact convex tooth is N 间隔 The distance between the number of convex teeth and the air blowing pipe along the h direction is When the air-blown optical cable is pressed against the air-blown pipe, the convex teeth in contact with the air-blown pipe are deformed. ,if = , then set the number of N 摩擦 Contact with air blowing pipe.

[0033] and ,in b The calculation formula is as follows: ,in F / L is the contact force per unit length, more specifically, F is gravity, L is the length of the air-blown optical cable, E * is the equivalent elastic modulus, R * is the relative curvature radius. The contact half width is derived according to the Hertz pressure distribution model. b ,satisfy ,in x represents the horizontal direction of the contact plane, x =0 represents the contact center.

[0034] E *The calculation formula is as follows: ,in E凸 is the Young's modulus of the convex tooth, v 凸 is the Poisson's ratio of the convex tooth, E 管 is the Young's modulus of the air blowing pipe, v 管 is the Poisson's ratio of the air blowing pipe.

[0035] R * The calculation formula is as follows: ,in R 凸 is the curvature radius of the convex tooth, R 管 is the curvature radius of the air blowing pipe.

[0036] The material of the convex teeth is the same as that of the sheath body, which is HDPE high-density polyethylene. E 凸 500-1500MPa, v 凸 It is 0.35-0.45.

[0037] At present, some of the air-blown pipes used in actual production are also made of HDPE high-density polyethylene. 管 700-1500MPa, v 管 It is 0.33-0.43.

[0038] The number of convex teeth in this embodiment N The design not only considers the properties of the air-blown optical cable itself, but also combines the characteristics of the air-blown pipeline in actual application scenarios. The test results for the maximum number of teeth are as follows:

[0039] From the above test data, it can be seen that when the number of teeth is designed N Less than the calculated number of teeth N max The results of the air blowing test of the embodiment are all successful, and the number of designed teeth is N Greater than the calculated number of teeth N max The air blowing test results of the embodiments are all failures.

[0040] The method for designing the number of convex teeth of an air-blown optical cable and the air-blown optical cable of the present invention can obtain the range of the number of convex teeth by calculation, which can omit the test verification step, save test costs, omit the verification process, and shorten the production cycle. The air-blown optical cable obtained by this method can be quickly put into production and use, thereby improving product competitiveness.

[0041] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0042] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for designing the number of protruding teeth of an air-blown optical cable, the air-blown optical cable comprising a cable core and an outer sheath, the outer sheath comprising a sheath body and a plurality of protruding teeth arranged in an array surrounding the sheath body, the air-blown optical cable being intended for installation in an air-blown duct, characterized in that: The number of teeth of the outer sheath along the axial section is N, where N is an integer and satisfies N ≥ N min , ,in , is half of the angle between two adjacent convex teeth. R 齿尖 It is the distance from the axis of the air-blown optical cable to the end of the convex tooth. R 齿根 It is the distance from the axis of the air-blown cable to the root of the convex teeth. R 管 is the radius of the air blowing pipe.

2. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 1, characterized in that: Number of teeth N satisfy N ≤ N max ,in ,in N 间隔 is the difference between the convex tooth that contacts the air blowing pipe the farthest and the convex tooth that contacts the air blowing pipe in the middle. The distance between the convex tooth that is farthest in contact with the air blowing pipe and the air blowing pipe along the contact direction, Equal to the deformation of the convex teeth in contact with the air blowing pipe in the middle , , R 凸 is the curvature radius of the convex tooth, b It is the maximum half-width of the contact between the convex teeth in the middle that contacts the air blowing pipe and the air blowing pipe.

3. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 2, wherein: b The calculation formula is as follows: ,in F / L is the contact force per unit length, F is gravity, L is the length of the air-blown cable, E * is the equivalent elastic modulus, R * is the relative radius of curvature.

4. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 3, wherein: E * The calculation formula is as follows: ,in E 凸 is the Young's modulus of the convex tooth, v 凸 is the Poisson's ratio of the convex tooth, E 管 is the Young's modulus of the air blowing pipe, v 管 is the Poisson's ratio of the air blowing pipe.

5. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 4, characterized in that: The material of the convex teeth is the same as that of the sheath body, which is HDPE high-density polyethylene. E 凸 500-1500MPa, v 凸 It is 0.35-0.

45.

6. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 3, wherein: R * The calculation formula is as follows: ,in R 凸 is the curvature radius of the convex tooth, R 管 is the curvature radius of the air blowing pipe.

7. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 2, wherein: N 间隔 =3。 8. The method for designing the number of protruding teeth of an air-blown optical cable according to claim 1, wherein: Tooth height , H : R 齿根 It is 1:40~1:

20.

9. An air-blown optical cable, characterized in that: The air-blown optical cable includes a cable core and an outer sheath, the outer sheath includes a sheath body and a plurality of convex teeth arranged in an array around the sheath body, and the number range of the convex teeth is obtained by the method for designing the number of convex teeth of the air-blown optical cable according to any one of claims 1-8.

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