Novel voltage-sharing shielding ring single welded junction mast bending process

Abstract

The invention belongs to the field of voltage-sharing shielding rings, and particularly relates to a novel voltage-sharing shielding ring single welded junction mast bending process which comprises the following steps: cutting an aluminum alloy pipe according to the design size of a voltage-sharing shielding ring, and carrying out surface treatment on the cut aluminum alloy pipe to obtain a pipe material meeting the process requirement; although the whole pipe is of an annular structure after mast bending, the two ends of the pipe are in a staggered state, the traction mechanism and the guide mechanism are arranged on the die table, deviation correction of the annular pipe after mast bending is conducted is conducted, the annular channel clamped by the guide seat and the limiting seat is matched with rotation, and the annular pipe can be adjusted to the same pipe center. And after multiple times of rotation, the two ends of the annular tubular pipe are attached and closed, and the single welded junction of the medium-voltage shielding ring is formed in cooperation with welding equipment. The mast-bent pipe material is welded and formed into an integrated structure through a single welded junction, the angle and the radius of an annular mechanism are uniform, corona at all point positions is balanced, the problem that corona at a welding seam is unbalanced due to too many welded junctions is solved, and the use safety and stability are improved.

Description

Technical Field

[0001] The invention relates to the field of voltage-equalizing shielding rings, and in particular to a novel single-weld mast bending process for voltage-equalizing shielding rings. Background Art

[0002] The grading ring is a ring-shaped protective hardware that improves the voltage distribution of the insulator string. In the stable operation of the power system, the grading shielding ring plays an irreplaceable key role. It can improve the electric field distribution around the insulator string, prevent the occurrence of corona discharge and partial discharge, and ensure the safe and stable operation of the power system.

[0003] The existing equalizing shielding rings have multiple welds during processing. On the one hand, multiple welds result in a large welding workload. On the other hand, there is a large difference between the welds and normal materials, resulting in unstable weld quality. In actual use, the welds of the welds will affect the normal distribution of the electric field around the insulator string, posing a safety hazard. This makes it difficult for the processed equalizing shielding rings to meet the increasingly stringent requirements of today's power equipment due to their shape accuracy. Summary of the invention

[0004] (I) Purpose of the invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes a new type of single-weld mast bending process for a pressure-equalizing shielding ring, which has the characteristics of one-piece molding to reduce the number of welds and stable molding structure.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the present invention provides a novel pressure-equalizing shielding ring single-weld mast bending process, comprising the following steps:

[0008] Step 1: Cut the aluminum alloy pipe according to the design size of the pressure-equalizing shielding ring, and perform surface treatment on the cut aluminum alloy pipe to obtain a pipe material that meets the process requirements;

[0009] Step 2: transport any end of the pipe material to the cavity of the mast bending machine, and the pipe material is pushed and deformed along the cavity designed according to the bending angle and radius required by the pressure-equalizing shielding ring. The mast bending end applies pressure to the pipe material, and the pipe material is bent into a ring tube shape under the constraints of the pressure and the cavity;

[0010] Step 3: Place the annular tube-shaped pipe material on the guide mechanism to support and limit the pipe material, and cooperate with the traction mechanism to pull and shape the annular tube-shaped pipe material;

[0011] Step 4: Butt the two ends of the pipe to form a welded joint, and weld the welded joint of the pipe by welding equipment to form a pressure-equalizing shielding ring;

[0012] Step 5: heat treat the voltage-equalizing shielding ring to eliminate the residual stress generated during the welding process, and then perform surface polishing to reduce the surface roughness of the voltage-equalizing shielding ring.

[0013] The selected aluminum alloy pipe has good electrical conductivity and mechanical properties. The aluminum alloy pipe is cut by a cutting machine, and welding areas are reserved at both ends of the cut pipe.

[0014] The surface treatment of aluminum alloy pipes includes mechanical treatment and chemical treatment; mechanical treatment is to remove the oxide layer on the surface of the pipe by sandblasting, and chemical treatment is to remove oil stains and rust on the surface of the pipe by degreasing and neutralization.

[0015] Preferably, the shape and size of the cavity of the mast bending machine are compatible with the pressure-equalizing shielding ring, and angle control devices and radius control devices are arranged at multiple points in the cavity.

[0016] Preferably, the two ends of the annular tubular pipe are close to each other after mast bending, and welds are left at both ends. During the mast bending process, the angle control device and the radius control device are used to monitor the bending angle and radius in real time to ensure that the bending parameters meet the process requirements.

[0017] Preferably, the traction mechanism and the guide mechanism are arranged on the mold platform, wherein the traction mechanisms are symmetrically arranged in pairs in the middle of the mold platform, and the guide mechanism is arranged in a ring-shaped manner between two adjacent traction mechanisms.

[0018] Preferably, the traction mechanism includes a base mounted on the mold platform, on which an "L-shaped" structured axle frame is symmetrically mounted, through which runs an axle rod whose rotation is controlled by a driving device, and on the outer wall of the axle rod are provided rollers, and between two adjacent rollers a traction channel is clamped.

[0019] Preferably, the guiding mechanism includes a guiding seat and a limiting seat, wherein the guiding seat is installed on the upper part of the mold platform and has an annular groove on the top that matches the specifications of the medium-voltage shielding ring, and the limiting seat is inserted into the upper part of the guiding seat, and the guiding seat has a pressing groove that matches the annular groove, and the medium-voltage shielding ring is pulled through the groove clamped by the two.

[0020] Preferably, the traction mechanism pulls the annular tubular pipe material in the same direction, and the two ends of the annular tubular pipe material are connected by fine-tuning the traction in the positive and negative directions. The annular tubular pipe material connects the two ends of the pipe material to form a welded joint, and the welded joint of the pipe material is welded by welding equipment at any notch position on the mold platform to form a pressure-equalizing shielding ring.

[0021] Preferably, the heating device heats up to 300°C-400°C to preheat the voltage-equalizing shielding ring, and keeps it warm for 30-40 minutes to rebalance the stress inside the voltage-equalizing shielding ring. The heated voltage-equalizing shielding ring is quickly cooled by a cooling medium, and the regrowth of grain boundaries is prevented by rapid cooling to release and eliminate welding residual stress.

[0022] Preferably, the pressure-equalizing shielding ring is placed again between the traction mechanism and the guide mechanism, and the surface is polished through the cooperation of the traction mechanism and the guide mechanism to reduce the surface roughness of the pressure-equalizing shielding ring.

[0023] The above technical solution of the present invention has the following beneficial technical effects:

[0024] 1. Although the pipe material is annular as a whole after the mast is bent, its two ends are staggered. A traction mechanism and a guide mechanism are set on the mold table to correct the deviation of the annular tubular pipe material after the mast is bent. The annular channel clamped by the guide seat and the limit seat can be adjusted to the same pipe center by rotation. After multiple rotations, the two ends of the annular tubular pipe material are attached and closed, and the single weld of the medium-voltage shielding ring is formed in cooperation with the welding equipment.

[0025] 2. The pipe material after mast bending is welded into an integrated structure through a single weld. The angle and radius of the annular structure are uniform, and the corona at each point is balanced, which solves the problem of unbalanced corona at the weld caused by too many welds and improves the safety and stability of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the process flow of the present invention

[0027] Figure 2 This is a schematic diagram of the shielding ring mounting mold platform structure of the present invention;

[0028] Figure 3 It is a schematic diagram of the mold platform structure of the present invention;

[0029] Figure 4 It is a schematic diagram of the structure of the guide mechanism of the present invention;

[0030] Figure 5 It is the guide mechanism separation mechanism of the present invention.

[0031] Reference numerals:

[0032] 1. Die table; 21. Base; 22. Shaft frame; 23. Shaft rod; 24. Roller; 31. Guide seat; 32. Limit seat. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0034] like Figure 1-5 As shown, a novel pressure-equalizing shielding ring single-weld mast bending process proposed by the present invention comprises the following steps:

[0035] Step 1: Cut the aluminum alloy pipe according to the design size of the pressure-equalizing shielding ring, and perform surface treatment on the cut aluminum alloy pipe to obtain a pipe material that meets the process requirements;

[0036] The selected aluminum alloy pipe has good electrical conductivity and mechanical properties. The aluminum alloy pipe is cut by a cutting machine. The welding intervals at both ends of the cut pipe are reserved. The welding intervals at both ends should have the same length and pipe diameter. After the pipe is bent, the reserved welding intervals are attached and aligned, and rounding is performed to facilitate welding the pipe into an integrated ring structure.

[0037] The surface treatment of aluminum alloy pipes includes mechanical treatment and chemical treatment; mechanical treatment is to remove the oxide layer on the pipe surface by sandblasting, and chemical treatment is to remove oil stains and rust on the pipe surface by degreasing and neutralizing, in order to make the pipe surface smooth, to prevent the aluminum alloy pipe surface from being scratched and worn due to roughness and dirt during mast bending, and to provide a processing basis for subsequent mast bending and welding;

[0038] Step 2: transport any end of the pipe material to the cavity of the mast bending machine, and the pipe material is pushed and deformed along the cavity designed according to the bending angle and radius required by the pressure-equalizing shielding ring. The mast bending end applies pressure to the pipe material, and the pipe material is bent into a ring tube shape under the constraints of the pressure and the cavity;

[0039] Among them, the shape and size of the cavity of the mast bending machine are adapted to the pressure-equalizing shielding ring, and angle control devices and radius control devices are set at multiple points in the cavity. The two ends of the annular tubular pipe after mast bending are close to each other, and welds are left at both ends. During the mast bending process, the angle control device and radius control device are used to monitor the bending angle and radius in real time to ensure that the bending parameters meet the process requirements;

[0040] In the present application, during the process of forming a circular tubular structure into a mast bend, the angle and radius monitored in the mold cavity are switched from being monitored by a single angle control device and a radius control device to being monitored collaboratively by multiple points, thereby ensuring that the circular tubular pipe generated by the mast bend has an approximate angle and radius.

[0041] It can be understood that the angle control device can ensure that the pipe reaches a predetermined angle during the mast bending process. Through driving methods such as servo motors or hydraulic systems, the angle control device can accurately adjust the angle of the mast bend end, thereby achieving precise control of the mast bend angle of the pipe.

[0042] Correspondingly, the radius control device cooperates with the cavity, and multi-point monitoring of the annular tube radius of the pipe bending can ensure that the pipe maintains a stable radius size during the bending process.

[0043] Step 3: Place the annular tube-shaped pipe material on the guide mechanism to support and limit the pipe material, and cooperate with the traction mechanism to pull and shape the annular tube-shaped pipe material;

[0044] Step 4: Butt the two ends of the pipe to form a welded joint, and weld the welded joint of the pipe by welding equipment to form a pressure-equalizing shielding ring;

[0045] Step 5: heat treat the voltage-equalizing shielding ring to eliminate the residual stress generated during the welding process, and then perform surface polishing to reduce the surface roughness of the voltage-equalizing shielding ring.

[0046] It should be noted that: the traction mechanism and the guide mechanism are arranged on the mold platform 1, wherein the traction mechanisms are symmetrically arranged in pairs in the middle of the mold platform 1, and the guide mechanism is arranged in a ring-shaped interval between two adjacent traction mechanisms. In the present application, the traction mechanisms are arranged at equal angles on four mold platforms 1, and the spacing between the two traction mechanisms is the same as the diameter of the annular tubular pipe. The guide mechanism is used to transport and support the annular tubular pipe during the annular displacement process.

[0047] Take the operation of the traction mechanism as an example: the traction mechanism includes a base 21 installed on the mold table 1, and an "L-shaped" structure shaft frame 22 is symmetrically installed on the base 21. A shaft rod 23 controlled by the driving device to rotate passes through the shaft frame 22. The outer wall of the shaft rod 23 is sleeved with rollers 24, and a traction channel is clamped between two adjacent rollers 24; when the traction mechanism is working, one of the shaft rods 23 is controlled by the driving device to rotate, thereby driving the rollers 4 to rotate, and pushing the annular tubular pipe along the traction channel. At this time, each roller 4 rotates in the same direction, driving the annular tubular pipe to make an annular rotational motion in the annular traction channel.

[0048] Take the work of the guide mechanism as an example: the guide mechanism includes a guide seat 31 and a limit seat 32. The guide seat 31 is installed on the upper part of the mold base 1, and an annular groove adapted to the specifications of the medium-voltage shielding ring is opened on the top. The limit seat 32 is plugged into the upper part of the guide seat 31. The guide seat 31 is provided with a pressing groove matching the annular groove. The medium-voltage shielding ring is pulled through the groove clamped by the two. The annular tubular pipe is lowered by the traction channel clamped by two rollers 4, and the bottom is initially supported by the guide seat 31 with an annular groove, and the upper part is surrounded and limited by the downwardly pressed limit seat 32. The two form an annular channel to support the annular tubular pipe during the traction process and fine-tune the shape.

[0049] It can be understood that several guide seats 31 are arranged between two adjacent traction mechanisms, and the number of guide seats 31 is adjusted according to the pipe diameter of the medium-voltage shielding ring to ensure that at least three are arranged within an angle of 30°, which is adapted to the annular tubular pipe material of the mast bend and reduces the position where support is lacking during the rotation process, with the aim of ensuring stable support and guidance of the annular tubular pipe material.

[0050] In this embodiment, since the aluminum alloy pipe is annular in structure as a whole after mast bending, its two ends are staggered and cannot be attached to each other. A traction mechanism and a guide mechanism are provided on the mold platform 1 to correct the deviation of the annular tubular pipe after mast bending. The edges of the annular tubular pipe are supported and limited by various guide mechanisms and pulled by the traction mechanism. During the rotation, the annular channel clamped by the guide seat 31 and the limit seat 32 cooperates with the rotation to adjust the annular tubular pipe to the same pipe core. After multiple rotations, the two ends of the annular tubular pipe are attached and closed, and the single weld joint of the medium-voltage shielding ring is formed in cooperation with the welding equipment.

[0051] In one embodiment, the traction mechanism pulls the annular tubular pipe in the same direction, and the two ends of the annular tubular pipe are connected by fine-tuning the traction in the positive and negative directions. The annular tubular pipe connects the two ends of the pipe to form a welded joint, and the welded joint of the pipe is welded by welding equipment at any notch position on the mold platform 1. The purpose of welding on the mold platform 1 is to serve as a temporary welding support structure to prevent the welded joints at both ends of the annular tubular pipe from being separated due to lack of limiting, thereby ensuring the quality of the single weld, the weld is uniform, free of pores and cracks, and the welding strength reaches more than 90% of the strength of the material itself, forming an annular pressure-equalizing shielding ring.

[0052] In one embodiment, the heating device is heated to 300° C. to preheat the voltage-equalizing shielding ring, and the temperature is kept for 30 to rebalance the stress inside the voltage-equalizing shielding ring. The heated voltage-equalizing shielding ring is quickly cooled by a cooling medium, and the regrowth of grain boundaries is prevented by rapid cooling to release and eliminate welding residual stress.

[0053] In another embodiment, the heating device heats up to 400°C to preheat the voltage-equalizing shielding ring, and keeps the temperature for 40 minutes to rebalance the stress inside the voltage-equalizing shielding ring. The heated voltage-equalizing shielding ring is quickly cooled by a cooling medium, and the regrowth of grain boundaries is prevented by rapid cooling to release and eliminate welding residual stress.

[0054] It is understandable that after the process is completed, a part of residual stress will remain inside the voltage-equalizing shielding ring. The residual stress can cause the voltage-equalizing shielding ring to rupture, deform or change in size. The residual stress also increases the chemical activity of the metal, which is particularly prone to intergranular corrosion rupture under the action of residual tensile stress. Therefore, the residual stress will affect the performance of the material or cause premature failure of the workpiece. The main parts for eliminating residual stress include the compression section of the inner wall of the ring, the tensile section of the outer wall of the ring and the welding end, thereby improving the performance stability of the material. In this application, the welding end is designed as a single weld, and the stress influence at the single weld is relatively low, thereby preventing the voltage-equalizing shielding ring from being damaged at multiple points during use.

[0055] In an optional embodiment, the voltage-equalizing shielding ring is placed again between the traction mechanism and the guide mechanism, and the surface is polished through the cooperation of the traction mechanism and the guide mechanism to reduce the surface roughness of the voltage-equalizing shielding ring. The roller of the traction mechanism can be improved, and sandpaper or grinding parts are attached to its periphery. The stress-eliminating voltage-equalizing shielding ring is finely polished until the surface roughness reaches Ra0.8μm (Ra0.8μm means that within the sampling length, the arithmetic mean of the absolute value of the contour deviation reaches 0.8 microns, and the smaller the value, the smoother the surface). The voltage-equalizing shielding ring with a smooth surface has multiple advantages in the power system, including reducing corona discharge, reducing radio interference, and improving the overall performance and reliability of the system.

[0056] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A new type of single weld mast bending process for a pressure-equalizing shielding ring, characterized in that: The following steps are involved: Step 1: Cut the aluminum alloy pipe according to the design size of the pressure-equalizing shielding ring, and perform surface treatment on the cut aluminum alloy pipe to obtain a pipe material that meets the process requirements; Step 2: transport any end of the pipe material to the cavity of the mast bending machine, and the pipe material is pushed and deformed along the cavity designed according to the bending angle and radius required by the pressure-equalizing shielding ring. The mast bending end applies pressure to the pipe material, and the pipe material is bent into a ring tube shape under the constraints of the pressure and the cavity; Step 3: Place the annular tube-shaped pipe material on the guide mechanism to support and limit the pipe material, and cooperate with the traction mechanism to pull and shape the annular tube-shaped pipe material; Step 4: Butt the two ends of the pipe to form a welded joint, and weld the welded joint of the pipe by welding equipment to form a pressure-equalizing shielding ring; Step 5: heat treat the voltage-equalizing shielding ring to eliminate the residual stress generated during the welding process, and then perform surface polishing to reduce the surface roughness of the voltage-equalizing shielding ring.

2. According to the novel single weld bending process of the voltage-equalizing shielding ring according to claim 1, it is characterized in that: The selected aluminum alloy pipe has good electrical conductivity and mechanical properties. The aluminum alloy pipe is cut by a cutting machine, and welding areas are reserved at both ends of the cut pipe. The surface treatment of aluminum alloy pipes includes mechanical treatment and chemical treatment; Mechanical treatment is to remove the oxide layer on the surface of the pipe by sandblasting, and chemical treatment is to remove oil and rust on the surface of the pipe by degreasing and neutralization.

3. According to the novel single weld bending process of the voltage-equalizing shielding ring of claim 1, it is characterized in that: The shape and size of the cavity of the mast bending machine are matched with the pressure-equalizing shielding ring, and angle control devices and radius control devices are arranged at multiple points in the cavity.

4. According to the novel single weld bending process of the voltage-equalizing shielding ring of claim 3, it is characterized in that: After the mast is bent, the two ends of the annular tubular pipe are close to each other and welds are left at both ends. During the mast bending process, the angle control device and radius control device are used to monitor the bending angle and radius in real time to ensure that the bending parameters meet the process requirements.

5. According to the novel single weld bending process of the voltage-equalizing shielding ring of claim 1, it is characterized in that: The traction mechanism and the guide mechanism are arranged on the die table (1), wherein the traction mechanisms are symmetrically arranged in pairs in the middle of the die table (1), and the guide mechanism is arranged in a ring-shaped manner between two adjacent traction mechanisms.

6. A novel single weld bending process for a voltage-equalizing shielding ring according to claim 5, characterized in that: The traction mechanism comprises a base (21) mounted on the die table (1), an L-shaped shaft frame (22) symmetrically mounted on the base (21), a shaft rod (23) controlled to rotate by a driving device passing through the shaft frame (22), a roller (24) sleeved on the outer wall of the shaft rod (23), and a traction channel sandwiched between two adjacent rollers (24).

7. A novel single weld bending process for a voltage-equalizing shielding ring according to claim 6, characterized in that: The guide mechanism comprises a guide seat (31) and a limit seat (32); the guide seat (31) is installed on the upper part of the die table (1), and an annular groove matching the specifications of the medium-voltage shielding ring is provided on the top; the limit seat (32) is plugged into the upper part of the guide seat (31); a pressing groove matching the annular groove is provided on the guide seat (31); the medium-voltage shielding ring is pulled through the groove clamped by the two.

8. A novel single weld bending process for a voltage-equalizing shielding ring according to claim 7, characterized in that: The traction mechanism pulls the annular tubular pipe material in the same direction, and the two ends of the annular tubular pipe material are butted together by fine-tuning the traction in the positive and negative directions. The annular tubular pipe material butts together the two ends of the pipe material to form a welded joint, and the welded joint of the pipe material is welded at any notch position on the mold platform (1) by a welding device to form a pressure-equalizing shielding ring.

9. The novel single weld bending process for a voltage-equalizing shielding ring according to claim 1 is characterized in that: The heating device heats up to 300℃-400℃ to preheat the voltage-equalizing shielding ring, and keeps the temperature for 30-40 minutes to rebalance the stress inside the voltage-equalizing shielding ring. The heated voltage-equalizing shielding ring is quickly cooled by a cooling medium, and the regrowth of grain boundaries is prevented by rapid cooling to release and eliminate welding residual stress.

10. The novel single weld bending process for a voltage-equalizing shielding ring according to claim 8 is characterized in that: The pressure-equalizing shielding ring is placed again between the traction mechanism and the guide mechanism, and the surface is polished through the cooperation of the traction mechanism and the guide mechanism to reduce the surface roughness of the pressure-equalizing shielding ring.

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