A cable joint expansion state measuring device and installation method thereof

Abstract

A cable joint expansion state measuring device and installation method thereof, the measuring device comprises a pair of conical truncated cones with the same structure, a screw positioning hole is provided in the center of the conical truncated cone, and a pair of conical truncated cones are connected together by a screw through the screw positioning hole; a plurality of truncated cone positioning belts are evenly distributed along the outer circumference of the screw positioning hole and extend to the edge, and the same number of expanded thin walls are arranged between the two conical truncated cones corresponding to the truncated cone positioning belts; the bottom surface of the conical truncated cone is processed with notches on both sides of the truncated cone positioning belt, and the supporting thin wall can be inserted through the notches; nuts are installed at both ends of the screws outside the two conical truncated cones, and when in use, the nuts are first screwed in to make the expanded thin wall drive the cable accessory sample outward along the truncated cone positioning belt to expand, and then the supporting thin wall is inserted through the notch on the bottom surface of the conical truncated cone, and a thin film pressure sensor is arranged between the supporting thin wall and the inner wall of the cable accessory sample. The present invention is more convenient to measure and the result is more accurate.

Description

Technical Field

[0001] The invention belongs to the field of rubber main insulated cable accessory interface pressure measurement, and in particular relates to a cable joint expansion state measuring device and an installation method thereof. Background Art

[0002] The primary goal of studying the interface pressure of rubber main insulated cable accessories is to measure the interface pressure. The built-in thin film pressure sensor method is one of the most widely used measurement methods at home and abroad. When using the built-in thin film pressure sensor to measure the interface pressure of rubber main insulated cable accessories, the first obstacle to overcome is the sensor installation method. Rubber main insulated cable accessories mainly adopt interference fit to ensure sufficient interface pressure, that is, through sufficient "holding force" to make the insulation interface sufficiently uniform and eliminate insulation defects such as air gaps, which means that the cable accessories need to be expanded first when installing the sensor.

[0003] At present, the cable accessory expansion equipment commonly used in the installation of cable accessories is expensive, not conducive to functional expansion, and relatively complicated to use. It is not suitable for studying interface pressure under laboratory conditions. Under laboratory conditions, nylon rods are generally used to complete cable expansion, that is, the sensor and nylon rods are tightly fitted and then inserted into the unexpanded cable accessory sample as a whole. This installation method is very cumbersome. First, the sensor and nylon rod are not easy to fit tightly, which can easily cause damage to the sensor film. In addition, in order to reduce the difficulty of placement, silicone oil is needed to reduce the friction between the nylon rod and the inner surface of the accessory, which also increases the possibility of the sensor film falling off, and it is also easy to cause silicone oil to penetrate into the sensor and cause damage to the sensor. Summary of the invention

[0004] The purpose of the present invention is to provide a cable joint expansion state measuring device and an installation method thereof to address the above-mentioned problems in the prior art, so that the interface pressure measurement of the rubber main insulated cable accessory sample is more convenient and the measurement result is more accurate.

[0005] In order to achieve the above object, the present invention has the following technical solutions:

[0006] A device for measuring the expansion state of a cable joint comprises a pair of conical truncated cones of the same structure, a screw positioning hole is provided in the center of the conical truncated cone, and a screw is installed through the screw positioning hole to connect the conical surfaces of the pair of conical truncated cones relative to each other; a plurality of truncated cone positioning belts are arranged on the conical surface of the conical truncated cone, which are evenly distributed along the outer circumference of the screw positioning hole and extend to the edge; the same number of expanded thin walls are arranged between the two conical truncated cones corresponding to the truncated cone positioning belts, and the middle parts of both ends of the expanded thin walls are processed with inclined grooves matching the truncated cone positioning belts; the bottom surface of the conical truncated cone is processed on both sides of the truncated cone positioning belt There is a notch, through which a supporting thin wall can be inserted; nuts are installed at both ends of the screws on the outside of the two conical cones. When in use, the cable accessory sample is first put on the expanded thin wall, and the nut is screwed in to make the expanded thin wall expand outward along the cone positioning belt, thereby driving the cable accessory sample to expand, and then the supporting thin wall is inserted through the notch on the bottom surface of the conical cone, and a thin film pressure sensor is arranged between the supporting thin wall and the inner wall of the cable accessory sample. Finally, the nut is screwed out to make the expanded thin wall retract, so that the cable accessory sample maintains the measured expansion rate, and the thin film pressure sensor measures the interface pressure of the cable accessory sample under interference fit.

[0007] As a preferred solution, the side edges of the truncated cone positioning belt are vertically arranged upward, and the inclination angle of the expanded thin-walled inclined groove is equal to that of the truncated cone positioning belt.

[0008] As a preferred solution, four truncated cone positioning belts are provided, and the angle between two adjacent truncated cone positioning belts is maintained at 90°. Four expanded thin-wall corresponding truncated cone positioning belts are provided.

[0009] As a preferred solution, four identical notches are machined on the bottom surface of the conical cone, and the center lines of two adjacent notches maintain an angle of 90°.

[0010] As a preferred solution, the inner surface of the notch is an arc surface, and the circle formed by the inner surface of the notch is concentric with the screw positioning hole.

[0011] As a preferred solution, the expanded thin wall and the supporting thin wall are both arc-shaped sheet structures, the circle formed by the expanded thin wall and the circle formed by the supporting thin wall are concentric with the screw positioning hole, and the inner surface of the supporting thin wall can fit with the inner surface of the notch.

[0012] As a preferred solution, the expanded thin wall and the supporting thin wall are both made of thin walls with corresponding expansion rates according to different expansion rates required for cable accessory sample measurement.

[0013] As a preferred solution, multiple thin film pressure sensors are arranged between the supporting thin wall and the inner wall of the cable accessory sample according to the need to measure interface pressure in different orientations of the cable accessory sample.

[0014] As a preferred solution, the conical cone, screw, expanded thin wall and supporting thin wall are all made of aluminum alloy.

[0015] A method for installing the cable joint expansion state measuring device comprises:

[0016] The screw-in loading method is adopted, and the expansion force is applied by screwing in the nuts installed at both ends of the screws on the outer sides of the two conical truncated cones;

[0017] Use the expanded thin wall and the supporting thin wall of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample as the expanded whole, and the expanded thin wall and the supporting thin wall form a cylinder of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample; first, evenly arrange the expanded thin wall inside the cable accessory sample, and after the cable accessory sample is expanded, place the supporting thin wall to form a cylinder of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample, so that the cable accessory sample maintains an expanded shape;

[0018] After the supporting thin wall is placed, a gap is maintained between the supporting thin wall and the inner wall of the cable accessory sample and a thin film pressure sensor is inserted. According to the measurement requirements, multiple thin film pressure sensors are arranged to measure the interface pressures at different positions of the cable accessory sample;

[0019] Gradually unscrew the nut to keep the cable accessory in the expanded state required for measurement and complete the installation.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The screw-in loading method is adopted. By screwing in the nuts installed at both ends of the screws on the outer sides of the two conical truncated cones, the expanded thin wall is expanded outward along the truncated cone positioning belt, driving the cable accessory sample to expand, and then the supporting thin wall is inserted through the bottom notch of the conical truncated cone. The thin film pressure sensor is arranged between the supporting thin wall and the inner wall of the cable accessory sample. Finally, the nut is gradually screwed out to keep the cable accessory in the expansion state required for measurement, that is, the cable accessory sample can maintain the expansion rate of measurement, and the thin film pressure sensor measures the interface pressure of the cable accessory sample under interference fit. The present invention can conveniently and quickly put in the thin film pressure sensor, and can effectively avoid damage to the sensor during installation, the measurement result is more accurate, and the measurement operation is more convenient and safe.

[0022] Furthermore, the expanded thin wall and the supporting thin wall of the present invention are both made of thin walls with corresponding expansion rates according to different expansion rates required for cable accessory sample measurement, and thin walls with different curvatures can be replaced as needed to achieve different expansion rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the examples of the present invention, the drawings required for use in the examples will be briefly introduced below. Obviously, the drawings described below are only some examples of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A schematic diagram of the three-dimensional structure of a conical frustum according to an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a three-dimensional structure of an expanded thin wall according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram of the overall assembly structure of a device for measuring the expansion state of a cable connector according to an embodiment of the present invention;

[0027] In the accompanying drawings: 101-screw positioning hole; 102-first truncated cone positioning belt; 103-second truncated cone positioning belt; 104-third truncated cone positioning belt; 105-fourth truncated cone positioning belt; 106-first notch; 107-second notch; 108-third notch; 109-fourth notch; 201-inclined groove; 301-screw; 302-first conical truncated cone; 303-first expanded thin wall; 304-second expanded thin wall; 305-third expanded thin wall; 306-fourth expanded thin wall; 307-second conical truncated cone; 308-first supporting thin wall; 309-second supporting thin wall; 310-third supporting thin wall; 311-fourth supporting thin wall. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0029] See also Figure 1-3The cable joint expansion state measuring device of the present invention comprises a pair of conical truncated cones with the same structure, a screw positioning hole 101 is opened in the center of the conical truncated cone, and a screw 301 is installed through the screw positioning hole 101 to connect the conical surfaces of the pair of conical truncated cones relative to each other; a plurality of truncated cone positioning belts are arranged on the conical surface of the conical truncated cone, which are evenly distributed along the outer circumference of the screw positioning hole 101 and extend to the edge, and the same number of expanded thin walls are arranged between the two conical truncated cones corresponding to the truncated cone positioning belts, and the middle parts of the two ends of the expanded thin walls are processed with inclined grooves 201 matching the truncated cone positioning belts; the bottom surface of the conical truncated cone is arranged on the truncated cone positioning belt. Notches are processed on both sides, and the supporting thin wall can be inserted through the notches; nuts are installed at both ends of the screw 301 on the outside of the two conical cones. When in use, the cable accessory sample is first put on the expanded thin wall, and the nut is screwed in to make the expanded thin wall expand outward along the cone positioning belt, thereby driving the cable accessory sample to expand, and then the supporting thin wall is inserted through the notch on the bottom surface of the conical cone, and a thin film pressure sensor is arranged between the supporting thin wall and the inner wall of the cable accessory sample. Finally, the nut is screwed out to make the expanded thin wall retract, so that the cable accessory sample maintains the measured expansion rate, and the thin film pressure sensor measures the interface pressure of the cable accessory sample under interference fit.

[0030] like Figure 1 As shown, the sides of the truncated cone positioning belt in this embodiment are all arranged vertically upwards, such as Figure 2 As shown, the inclination angle of the expanded thin-walled inclined groove 201 is equal to that of the truncated cone positioning belt. Figure 1 and Figure 3 As shown, in this embodiment, four truncated cone positioning belts are provided, and the angle between two adjacent truncated cone positioning belts is maintained at 90°, and four truncated cone positioning belts corresponding to the expanded thin wall are also provided. Furthermore, four identical notches are processed on the bottom surface of the conical truncated cone, and the center lines of two adjacent notches maintain an angle of 90°.

[0031] The inner surface of the notch in this embodiment is an arc surface, and the circle formed by the inner surface of the notch is concentric with the screw positioning hole 101. The expanded thin wall and the supporting thin wall are both arc-shaped sheet structures, and the circle formed by the expanded thin wall and the circle formed by the supporting thin wall are concentric with the screw positioning hole 101, and the inner surface of the supporting thin wall can fit the inner surface of the notch.

[0032] In a possible implementation, the expanded thin wall and the supporting thin wall are made of thin walls with corresponding expansion rates according to the different expansion rates required for the cable accessory sample measurement. Thin walls with different curvatures can be replaced as needed to achieve different expansion rates. The curvature is uniform everywhere, which can better simulate the internal structure of the cable and cable accessories. According to the needs of measuring the interface pressure of the cable accessory sample in different directions, multiple pieces of thin film pressure sensors are arranged between the supporting thin wall and the inner wall of the cable accessory sample. The thin film pressure sensor can be easily and quickly placed, and the sensor can be effectively prevented from being damaged during installation. The conical frustum, screw 301, expanded thin wall and supporting thin wall are all made of aluminum alloy. Made of aluminum alloy, it has high strength and its mechanical properties are close to those of cable armor and wire core.

[0033] See also Figure 1-3 The installation method of the cable joint expansion state measuring device according to the embodiment of the present invention comprises the following steps:

[0034] 1. Using a screw-in loading method, the first conical truncated cone 302 and the second conical truncated cone 307 are designed to cooperate with the screw 301 and the nut. When in use, the first conical truncated cone 302 and the second conical truncated cone 307 on both sides are clamped by screwing in the nut to apply expansion force;

[0035] 2. Use the arc thin wall with the inner diameter corresponding to the target expansion rate of the cable accessory sample as the expansion whole, with two groups in total, one group has four pieces, namely the first expanded thin wall 303, the second expanded thin wall 304, the third expanded thin wall 305, the fourth expanded thin wall 306 and the first supporting thin wall 308, the second supporting thin wall 309, the third supporting thin wall 310, and the fourth supporting thin wall 311. The eight arc thin walls form a cylinder with the inner diameter corresponding to the target expansion rate of the cable accessory sample. Thin walls with corresponding expansion rates can be manufactured for different expansion rates without changing the main body. When in use, first evenly arrange the four expanded thin walls on the inner side of the cable accessory sample, and after it is expanded, insert the four supporting thin walls to form a cylinder with the inner diameter corresponding to the target expansion rate of the cable accessory sample to maintain the expanded shape;

[0036] 3. After four thin supporting walls are placed, a certain gap is maintained between them and the inner wall of the cable accessory sample to insert the thin film pressure sensor. Multiple sensors can be arranged as needed to measure the interface pressure of the cable accessory sample in different directions, so that the measurement results are more accurate and the piezoelectric sensor will not be damaged;

[0037] 4. Finally, gradually loosen the nut to keep the cable accessories in the required expansion state to complete the installation.

[0038] The implementation process is described in more detail below in conjunction with the structure of the cable connector expansion state measuring device according to the embodiment of the present invention.

[0039] When in use, first pass the screw 301 through the screw positioning hole 101, and then pass the cable accessory sample through the screw 301 and place it at the center of the cone surface of the first conical truncated cone 302. The first truncated cone positioning belt 102, the second truncated cone positioning belt 103, the third truncated cone positioning belt 104, and the fourth truncated cone positioning belt 105 cooperate with the inclined grooves 201 of the four expanded thin walls to avoid the displacement of the expanded thin walls during installation and cause installation failure. When in use, place the first expanded thin wall 303, the second expanded thin wall 304, the third expanded thin wall 305, and the fourth expanded thin wall 306 into the cable accessory sample, and align the positioning grooves with the corresponding truncated cone positioning belts of the first conical truncated cone 302. Then, place the second conical truncated cone 307 at the other end of the cable accessory sample, and similarly make the first expanded thin wall 303, the second expanded thin wall 304, the third expanded thin wall 305, and the fourth expanded thin wall 306 cooperate with the truncated cone positioning belt of the second conical truncated cone 307. After completion, nuts are screwed into the outer sides of the first conical truncated cone 302 and the second conical truncated cone 307 , and the nuts are slowly tightened using a wrench.

[0040] Compared with the traditional method of directly using nylon rods to squeeze into the cable accessories for interference fit, the present invention uses the progressive expansion of nuts, which is faster and more labor-saving. At this time, as the nut is gradually tightened, the first conical cone 302 and the second conical cone 307 gradually approach each other, and the first expanded thin wall 303, the second expanded thin wall 304, the third expanded thin wall 305 and the fourth expanded thin wall 306 expand outward along their respective cone positioning bands. At the same time, the cable accessory sample is gradually expanded into a rounded rectangular cylinder until the first supporting thin wall 308, the second supporting thin wall 309, the third supporting thin wall 310 and the fourth supporting thin wall 311 can be inserted between the inner wall of the cable accessory sample and the first notch 106, the second notch 107, the third notch 108 and the fourth notch 109 on the bottom surface of the conical cone. The first supporting thin wall 308, the second supporting thin wall 309, the third supporting thin wall 310 and the fourth supporting thin wall 311 are inserted into the inner wall of the cable accessory sample and the first notch 106, the second notch 107, the third notch 108 and the fourth notch 109 on the bottom surface of the conical cone. After the support thin wall 310 and the fourth support thin wall 311 are inserted, the thin film pressure sensor to be arranged is inserted between the first support thin wall 308, the second support thin wall 309, the third support thin wall 310, the fourth support thin wall 311 and the inner wall of the cable accessory sample. Compared with the original method of squeezing the sensor into the cable accessory together with the nylon rod and other diameter expansion objects, the operation according to the present invention can avoid the displacement of the sensor and protect the sensor from damage to the greatest extent. In addition, the optical fiber temperature sensor and other sensing devices can be installed as needed. Finally, the nuts on both sides are loosened with a wrench to restore the cable accessory sample to a cylindrical tube shape, and the expansion rate is maintained to measure the interface pressure of the cable accessory sample under interference fit.

[0041] After testing and verification, the inner diameter expansion rate of the sample after actual installation is 149.5%, while the cable joint expansion rate is between 120% and 150%. It can be seen that the cable joint expansion state measuring device of the present invention can simulate the cable joint expansion state well.

[0042] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A device for measuring the expansion state of a cable joint, characterized in that: The invention comprises a pair of conical truncated cones with the same structure, wherein a screw positioning hole (101) is provided at the center of the conical truncated cones, and a screw (301) is installed through the screw positioning hole (101) to connect the conical surfaces of the pair of conical truncated cones relative to each other; a plurality of conical truncated cone positioning belts are arranged on the conical surface of the conical truncated cones, which are evenly distributed along the outer circumference of the screw positioning hole (101) and extend to the edge; an equal number of expanded thin walls are arranged between the two conical truncated cones corresponding to the conical truncated cone positioning belts, and the middle parts of the two ends of the expanded thin walls are processed with inclined grooves (201) matching the conical truncated cone positioning belts; the bottom surface of the conical truncated cone is provided with a plurality of conical truncated cone positioning belts on both sides of the conical truncated cone positioning belts. A notch is processed, through which a supporting thin wall can be inserted; nuts are installed at both ends of the screw rod (301) outside the two conical cones. When in use, the cable accessory sample is firstly put on the expanded thin wall, and the nut is screwed in to make the expanded thin wall expand outward along the cone positioning belt, thereby driving the cable accessory sample to expand, and then the supporting thin wall is inserted through the notch on the bottom surface of the conical cone, and a thin film pressure sensor is arranged between the supporting thin wall and the inner wall of the cable accessory sample, and finally the nut is screwed out to make the expanded thin wall retract, so that the cable accessory sample maintains the measured expansion rate, and the thin film pressure sensor measures the interface pressure of the cable accessory sample under interference fit.

2. The cable joint expansion state measuring device according to claim 1, characterized in that: The side edges of the truncated cone positioning belt are arranged vertically upwards, and the inclination angle of the expanded thin-walled inclined surface groove (201) is equal to that of the truncated cone positioning belt.

3. The cable joint expansion state measuring device according to claim 1, characterized in that: Four truncated cone positioning belts are provided, and the angle between two adjacent truncated cone positioning belts is maintained at 90°. Four expanded thin-wall corresponding truncated cone positioning belts are provided.

4. The cable joint expansion state measuring device according to claim 3, characterized in that: Four identical notches are processed on the bottom surface of the conical truncated cone, and the center lines of two adjacent notches maintain an angle of 90 degrees.

5. The cable joint expansion state measuring device according to claim 4, characterized in that: The inner surface of the notch is an arc surface, and the circle formed by the inner surface of the notch is concentric with the screw positioning hole (101).

6. The cable joint expansion state measuring device according to claim 5, characterized in that: The expanded thin wall and the supporting thin wall are both arc-shaped sheet structures. The circle formed by the expanded thin wall and the circle formed by the supporting thin wall are concentric with the screw positioning hole (101), and the inner surface of the supporting thin wall can fit with the inner surface of the notch.

7. The cable joint expansion state measuring device according to claim 1, characterized in that: The expanded thin wall and the supporting thin wall are both made of thin walls with corresponding expansion rates according to different expansion rates required for measuring cable accessory samples.

8. The cable joint expansion state measuring device according to claim 1, characterized in that: According to the interface pressure measurement requirements of cable accessory samples in different directions, multiple thin film pressure sensors need to be arranged between the supporting thin wall and the inner wall of the cable accessory sample.

9. The cable joint expansion state measuring device according to claim 1, characterized in that: The conical truncated cone, the screw (301), the expanded thin wall and the supporting thin wall are all made of aluminum alloy.

10. A method for installing the cable joint expansion state measuring device according to any one of claims 1 to 9, characterized in that: include: A screw-in loading method is adopted to apply expansion force by screwing in nuts installed at both ends of two conical truncated cone outer screws (301); Use the expanded thin wall and the supporting thin wall of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample as the expanded whole, and the expanded thin wall and the supporting thin wall form a cylinder of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample; first, evenly arrange the expanded thin wall inside the cable accessory sample, and after the cable accessory sample is expanded, place the supporting thin wall to form a cylinder of the inner diameter corresponding to the target diameter expansion rate of the cable accessory sample, so that the cable accessory sample maintains an expanded shape; After the supporting thin wall is placed, a gap is maintained between the supporting thin wall and the inner wall of the cable accessory sample and a thin film pressure sensor is inserted. According to the measurement requirements, multiple thin film pressure sensors are arranged to measure the interface pressure at different positions of the cable accessory sample; Gradually unscrew the nut to keep the cable accessory in the expanded state required for measurement and complete the installation.

Images