A transformer compensation type spring presser device

Abstract

The present application relates to the field of power transformer structure, provide a kind of transformer compensation type spring press nail device, including base, sleeve, spring and locking piece;The coil of transformer is used for pressing in the lower side of base, sleeve is set above base and lower end clearance fit with the oil inlet formed by base, spring is compressed and installed in sleeve and extrudes the upper side of base, the outlet is provided in the upper end of sleeve, locking piece is installed on the clamping piece support plate above coil and lower end is abutted with the upper end of sleeve.The present application is filled with oil by bottom and cooperates with top exhaust, avoids air remaining when filling oil, and improves coil pressing stability by using spring self-adapting compensation pressing force.

Description

Technical Field

[0001] This invention relates to the field of power transformer structural components, and specifically to a transformer compensation type spring clamping device. Background Technology

[0002] In large-capacity power transformers of 110kV and above, coils are typically clamped with pressure pins to ensure structural stability. However, during long-term transformer operation, the clamping force of traditional rigid pressure pins gradually decreases due to creep and shrinkage of the coil material, as well as thermal expansion and contraction caused by fluctuating ambient temperatures. This leads to increased axial displacement of the coil, increased operating noise, and reduced resistance to short-circuit impacts. While existing technologies utilize springs for elastic compensation in pressure pin structures, their internal construction is complex. During transformer vacuum oil filling, residual air inside the pressure pins is difficult to expel, potentially causing safety hazards such as partial discharge. Therefore, there is an urgent need for a pressure pin device that can adaptively provide stable clamping force while effectively removing internal air. Summary of the Invention

[0003] To address the problem of air being difficult to expel from the internal structure of elastic pressure nails during vacuum oil injection in existing technologies, this application proposes a transformer-compensated spring pressure nail device to achieve adaptive compensation of the clamping force and reliable air venting during the oil injection process.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A transformer compensation type spring clamping device includes a base, a sleeve, a spring, and a locking component; The lower side of the base is used to press the transformer coil. The sleeve is set above the base. The lower end of the sleeve and the base are fitted with a clearance to form an oil inlet. The spring is compressed and installed inside the sleeve to press the upper side of the base. The upper end of the sleeve is provided with an air outlet. The locking element is installed on the clamping support plate above the coil. The lower end of the locking element abuts against the upper end of the sleeve.

[0005] Furthermore, the upper end of the base extends into the lower end of the sleeve, and the gap width w between the base and the sleeve is no greater than 1mm.

[0006] Furthermore, the locking component includes a screw and a lower nut. The clamping support plate is provided with a mounting hole. The screw passes through the mounting hole and penetrates the clamping support plate. The lower end of the screw abuts against the upper end of the sleeve. The lower nut is threaded onto the screw and abuts against the lower side of the clamping support plate.

[0007] Furthermore, the air outlet is located at the center of the upper end of the sleeve, and the lower end of the screw abuts against the center of the upper end of the sleeve. An air passage is provided in the lower end of the screw, with one end of the air passage extending through to the lower end face of the screw and connected to the air outlet, and the other end extending through to the side of the screw.

[0008] Furthermore, a limiting groove is provided at the upper end of the sleeve, and the lower end of the screw extends into the limiting groove and abuts against the bottom of the limiting groove.

[0009] Further, the spring is a disc spring, and multiple disc springs are stacked up and down in the sleeve.

[0010] Further, the locking member further includes an upper nut, and the upper nut is screwed onto the screw rod to press the upper side of the clamping piece support plate.

[0011] Further, when installing the spring pressing nail device, after assembling the base, the spring and the sleeve, the base is abutted against the upper side of the coil. The screw rod passes through the clamping piece support plate through the mounting hole, and the lower nut is screwed into the lower end of the screw rod to squeeze the screw rod downward. The lower end of the screw rod squeezes the coil through the sleeve, the spring and the base. When the compression amount of the spring reaches the target value, the screw rod continues to move downward for a secondary distance d, where 1 mm < d < 5 mm. After the lower nut is screwed upward to abut against the lower side of the clamping piece support plate, the screw rod is released, and the lower nut presses the lower side of the clamping piece support plate. Finally, the upper nut is tightened on the screw rod.

[0012] Through the above improvements, the transformer compensation type spring pressing nail device proposed in this application has the following beneficial effects: 1. A gap fit between the lower end of the sleeve and the base forms an oil inlet, and an air outlet is provided at the upper end of the sleeve, so that insulating oil can enter the inside of the sleeve from the bottom during the vacuum oil injection process, and at the same time, the air in the sleeve is discharged upward through the top air outlet, avoiding air retention in the sleeve cavity and reducing the risk of partial discharge; <000003​​​​​​​​​​7. By setting the spring to compress to the target value and then applying a small amount of secondary pressure, the lower nut naturally fits against the lower side of the clamp support plate under the spring's rebound force, avoiding surface damage or metal debris caused by traditional forced tightening of the nut, thus improving transformer safety. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the spring-loaded nail device in an embodiment.

[0014] Figure 2 This is a schematic diagram of the screw being pressed down in an embodiment.

[0015] Figure 3 This is a schematic diagram of the air venting of the spring-loaded nail device in an embodiment.

[0016] Among them, 1-base, 2-sleeve, 3-spring, 4-locking part, 41-screw, 42-lower nut, 43-upper nut, 5-clamping support plate, 6-oil inlet, 7-air outlet, 8-air passage, 9-limiting groove. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] like Figures 1 to 3 As shown, this embodiment provides a transformer compensation type spring clamping device for a transformer with built-in coils and clamping support plates. The spring clamping device specifically includes a base 1, a sleeve 2, a spring 3, and a locking member 4. The lower side of the base 1 is used to clamp the transformer coil. The sleeve 2 is set above the base 1, and the lower end of the sleeve 2 is clearance-fitted with the base 1 to form an oil inlet 6. The spring 3 is compressed and installed inside the sleeve 2, pressing against the upper side of the base 1. The upper end of the sleeve 2 is provided with an air outlet 7. The locking member 4 is installed on the clamping support plate 5 above the coil, and the lower end of the locking member 4 abuts against the upper end of the sleeve 2.

[0020] Specifically, the base 1, as the terminal actuator for force transmission, has its lower end face directly contacting the upper pressure plate or insulating pad of the transformer coil, converting the elastic pressure from the spring 3 into an axial clamping force on the coil. The sleeve 2 covers the base 1; the two are not rigidly connected but achieve relative sliding guidance through a clearance fit. In this embodiment, the oil inlet 6 is a fluid channel naturally formed by the assembly gap between the outer circumferential surface of the base 1 and the inner circumferential surface of the sleeve 2. It should be understood that although the gap is shown as an annular slit in the figure, in other embodiments, the oil inlet 6 can also be formed by grooves, non-circular mating surfaces, or other forms of connecting structures opened on the surface of the base 1 or sleeve 2, as long as a continuous passage allowing insulating oil to pass through can be formed at the mating interface between the two.

[0021] During the vacuum oil filling process, insulating oil flows from bottom to top into the internal cavity of sleeve 2 through the gap between base 1 and the bottom of sleeve 2, i.e., oil inlet 6, under negative pressure. Because the density of insulating oil is greater than that of air and the flow direction is upward, the air originally inside the cavity of sleeve 2 is gradually lifted and eventually discharged through the vent 7 at the top of sleeve 2. The vent 7 is positioned at the upper end of sleeve 2, utilizing the physical property of natural gas rising to ensure that air does not stagnate in the dead corner at the top of the cavity. For example, the vent 7 can be a circular hole located at the center of the top cover of sleeve 2, an eccentrically positioned through hole, or a combination of multiple dispersed small holes, allowing the oil-gas replacement process to proceed smoothly. After the locking member 4 passes through the clamping support plate 5, its lower end presses against the top of sleeve 2, thereby transmitting the external preload through sleeve 2 and spring 3 to base 1, and then from base 1 to the coil. The spring 3 is compressed and deformed inside the sleeve 2, which not only provides the initial clamping force, but also automatically compensates for the displacement through its own expansion and contraction deformation when the coil undergoes height changes due to thermal expansion and contraction or material creep, thus maintaining the relative stability of the clamping force.

[0022] With the above setup, an oil inlet is formed by the gap between the base and the sleeve, and an air outlet is provided at the upper end of the sleeve, creating a one-way oil-air replacement path from bottom to top. This allows the insulating oil to fully fill the internal space of the sleeve while effectively expelling residual air. This avoids the problem of dead zones in oil injection caused by poor internal flow channels in traditional elastic pressure nail structures and reduces the safety hazard of partial discharge caused by air gap residue.

[0023] In one implementation, the upper end of the base 1 extends into the lower end of the sleeve 2, and the gap width w between the base 1 and the sleeve 2 is no greater than 1 mm. Specifically, the function of limiting the gap width w is to provide radial restraint for the relative sliding of the base 1 and the sleeve 2. When the gap width w is controlled within 1 mm, the upper end of the base 1 is effectively wrapped by the lower end of the sleeve 2, forming a mating section with a guiding function, which can constrain the base 1 to maintain a basically vertical movement posture when subjected to axial pressure. It should be understood that in this embodiment, the preferred gap width w is between 0.5 mm and 0.8 mm, but in other embodiments, as long as the gap can ensure the smooth flow of insulating oil to form the oil inlet 6 and limit the radial offset of the base 1 relative to the sleeve 2 to prevent the spring 3 from buckling laterally, it is within the protection scope of this invention. If the gap is too large, for example, more than 1 mm, the base 1 is prone to shaking under long-term alternating load, which will lead to uneven force on the internal spring 3 or even lateral bending failure. Conversely, if the gap is too small, it will increase the flow resistance of insulating oil into the sleeve 2, affecting the efficiency of oil injection and venting.

[0024] Through the above settings and clearance fit, while ensuring smooth oil and gas replacement, lateral buckling of the spring is effectively prevented, thus improving the overall reliability of the device operation.

[0025] Furthermore, a limiting groove 9 is provided at the upper end of the sleeve 2, and the lower end of the screw 41 extends into the limiting groove 9, abutting against the bottom of the groove 9. The limiting groove 9 is located at the center of the top cover of the sleeve 2, and its shape matches the contour of the lower end of the screw 41, while the air outlet 7 is located at the center of the bottom of the limiting groove 9. This structural design ensures that after the screw 41 is installed in place, its lower end is surrounded by the side wall of the limiting groove 9, thereby limiting the relative displacement between the screw 41 and the sleeve 2 in the horizontal direction and preventing accidental separation. Especially in the event of vibration during transformer transportation or operation, the limiting groove 9 can effectively prevent the screw 41 from slipping off the top of the sleeve 2, maintaining the integrity of the force transmission path. At the same time, the limiting groove 9 also plays a role in automatic alignment, ensuring that the air passage 8 inside the screw 41 is always connected to the air outlet 7 at the top of the sleeve 2, avoiding obstruction of the exhaust passage due to assembly deviation.

[0026] The above setup establishes an embedded connection between the screw and the sleeve, which enhances the vibration resistance and anti-detachment capabilities of the components and ensures the alignment and connectivity of the exhaust passage.

[0027] Furthermore, spring 3 is a butterfly spring, with multiple butterfly springs stacked vertically within sleeve 2. Compared to traditional cylindrical helical springs, butterfly springs have higher stiffness, stronger damping and vibration absorption capabilities, and the ability to withstand large loads with minimal deformation, making them ideal for transformers with limited axial installation space but high clamping force requirements. In this embodiment, multiple butterfly springs are arranged in series with vertical stacking. This stacking structure increases the total compression stroke of the spring assembly, enabling it to adapt to larger dimensional changes in the coil due to thermal expansion and contraction. It should be understood that the specific number of butterfly springs, their thickness, and cone height ratio can be adjusted according to the actual transformer capacity and clamping force requirements, and are not limited to the quantities shown in the accompanying drawings.

[0028] By utilizing the high load-bearing density characteristics of the disc spring and the stroke superposition effect of multiple stacked plates, a stable elastic compensation function is achieved within a limited sleeve space, which improves the adaptability of the pressing device to coil deformation and its long-term durability.

[0029] As one implementation, the locking component 4 includes a screw 41 and a lower nut 42. The clamping support plate 5 is provided with a mounting hole. The screw 41 passes through the mounting hole and penetrates the clamping support plate 5. The lower end of the screw 41 abuts against the upper end of the sleeve 2. The lower nut 42 is threadedly connected to the screw 41 and abuts against the lower side of the clamping support plate 5.

[0030] Specifically, the screw 41, acting as the carrier of axial force, passes through the mounting hole on the clamping support plate 5, and its bottom end directly presses against the top end face of the sleeve 2. The lower nut 42 is screwed onto the threaded section of the screw 41 located below the clamping support plate 5. When the lower nut 42 is rotated to move upward and press against the lower surface of the clamping support plate 5, the lower nut 42 becomes an upward support fulcrum. With the clamping support plate 5 as the support base, a clamping force is applied to the coil through the lower nut, screw 41, sleeve 2, spring 3, and base 1.

[0031] Through the above setup, a continuous force transmission path is constructed from the lower nut, screw, sleeve, spring to the base, applying a stable elastic clamping force to the coil, enabling the device to adapt to dimensional changes in the coil caused by thermal stress or creep, and maintaining the stability of the clamping force.

[0032] Furthermore, the air outlet 7 is located at the center of the upper end of the sleeve 2, and the lower end of the screw 41 abuts against the center of the upper end of the sleeve 2. An air passage 8 is provided in the lower end of the screw 41. One end of the air passage 8 extends through to the lower end face of the screw 41 and connects to the air outlet 7, while the other end extends through to the side of the screw 41. Since the lower end of the screw 41 will inevitably cover or block the air outlet 7 at the top of the sleeve 2 when installed, the exhaust channel would be cut off if a conventional solid screw structure were used. Therefore, in this embodiment, an air passage 8 is opened inside the lower end of the screw 41. The air passage 8 is L-shaped or T-shaped, with its inlet end precisely aligned with the air outlet 7 at the center of the sleeve 2, while the outlet end extends to the side wall of the screw 41 exposed outside the sleeve 2. During the vacuum oil filling process, the air that is compressed and rises inside the sleeve 2 by the insulating oil enters the air outlet 7 and will not be blocked by the screw 41. Instead, it flows into the air passage 8 and is discharged from the outlet on the side of the screw 41.

[0033] The above settings prevent exhaust interruption caused by the screw blocking the air outlet, ensuring the continuity and reliability of air discharge during vacuum oil injection.

[0034] In addition, the locking component 4 also includes an upper nut 43, which is screwed onto the screw 41 and presses against the upper side of the clamping support plate 5. In this embodiment, the upper nut 43 and the lower nut 42 together form a double-nut clamping anti-loosening structure. After the device is installed in place and the preload is adjusted, the upper nut 43 is screwed downward along the screw 41 so that it fits tightly against the upper surface of the clamping support plate 5. At this time, the clamping support plate 5 is firmly clamped between the upper nut 43 and the lower nut 42, preventing the screw 41 from moving axially. During the long-term operation of the transformer, the mutual locking force between the two nuts can effectively prevent the nuts from loosening and maintain a constant preload. It should be understood that the specifications of the upper nut 43 and the lower nut 42 can be the same, or different combinations of nuts with different thicknesses or strengths can be selected according to the force requirements.

[0035] By using the above settings, the bidirectional constraint effect of the upper and lower nuts on the clamping support plate improves the anti-loosening reliability and structural integrity of the device.

[0036] This embodiment further provides an installation method for a transformer compensation type spring clamping device. This installation method aims to reduce scratches and debris generated during installation and improve transformer safety through specific assembly timing and minor overvoltage control. The installation method specifically includes the following steps: In step S100, the base 1, spring 3, and sleeve 2 are assembled into a pre-assembled assembly, and the base 1 is placed against the upper side of the coil. Specifically, the assembly of the base, spring, and sleeve is completed in advance on the ground or workbench. The sleeve 2 is used to wrap around the spring 3 to prevent it from falling or becoming misaligned during transportation. Then, the entire assembly is placed in the predetermined installation position above the transformer coil, so that the lower end face of the base 1 is in full contact with the insulating pad on the upper side of the coil.

[0037] In step S200, the screw 41 is passed through the mounting hole into the clamping support plate 5, and the lower nut 42 is screwed into the lower end of the screw 41. At this time, the lower end of the screw 41 is embedded in the limiting groove 9 at the top of the sleeve 2 to ensure the coaxiality of the force transmission path. No preload is required on the lower nut 42 at this stage.

[0038] Step S300, as follows Figure 2 The drive cylinder presses the upper end of the screw 41 downwards, causing the lower end of the screw 41 to compress the coil through the sleeve 2, spring 3, and base 1. The drive cylinder is usually equipped with a force sensor or displacement sensor. When the pressure value begins to rise or the displacement changes abruptly, it indicates that the spring 3 has begun to enter its effective compression stroke. Using this moment as the reference zero point, the screw 41 continues to move downwards until the compression of the spring 3 reaches the preset target value, such as 5mm or other design compression calculated based on the transformer capacity.

[0039] In step S400, after the compression of spring 3 reaches the target value, the control screw 41 continues to move downward a second distance d, where 0.1mm... In step S500, while maintaining the downward pressure of the drive cylinder on the screw 41, tighten the lower nut 42 upwards until it abuts against the lower side of the clamping support plate 5. It is particularly important to emphasize that the lower nut 42 can be tightened by hand or with a wrench. Rotate the nut until you feel slight resistance, then stop. It is strictly forbidden to use tools to tighten it with excessive torque. This installation method is fundamentally different from traditional mechanical fastening: it avoids scratches and metal debris caused by high friction between the metal nut and the surface of the clamping support plate 5, eliminating the potential for foreign objects to fall into the transformer and cause insulation faults.

[0040] In step S600, the drive cylinder is released, separating the screw 41 from the drive source. Under the action of the elastic potential energy stored in the spring 3, the spring will have a slight upward rebound tendency. However, since the lower nut 42 was already in a light-abutting state in step S500, this rebound force will immediately be converted into a stable clamping force of the lower nut 42 on the lower side of the clamping support plate 5. Finally, the upper nut 43 is tightened downward along the screw 41 and pressed against the upper side of the clamping support plate 5, completing the double-nut anti-loosening lock.

[0041] The above settings avoid the safety risks of scratches and conductive debris caused by mechanical friction during assembly, ensuring the long-term stability and safety of the transformer coil compression state.

[0042] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the scope of protection of the appended claims.

Claims

1. A transformer compensation type spring clamping device, characterized in that, It includes a base, a sleeve, a spring, and a locking member; The lower side of the base is used to press the coil of the transformer. The sleeve is arranged above the base. There is a clearance fit between the lower end of the sleeve and the base, forming an oil inlet. The spring is compressively installed in the sleeve and presses the upper side of the base. An air outlet is provided at the upper end of the sleeve. The locking member is installed on the clamping plate above the coil, and the lower end of the locking member abuts against the upper end of the sleeve.

2. The transformer compensation type spring clamping device according to claim 1, characterized in that, The upper end of the base extends into the lower end of the sleeve, and the clearance width w between the base and the sleeve is not greater than 1 mm.

3. The transformer compensation type spring clamping device according to claim 1, characterized in that, The locking member includes a screw rod and a lower nut. An installation hole is provided on the clamping plate. The screw rod passes through the clamping plate through the installation hole. The lower end of the screw rod abuts against the upper end of the sleeve. The lower nut is threadedly connected to the screw rod and abuts against the lower side of the clamping plate.

4. A transformer compensation type spring clamping device according to claim 3, characterized in that, The air outlet is arranged at the center of the upper end of the sleeve. The lower end of the screw rod abuts against the center of the upper end of the sleeve. An air channel is provided in the lower end of the screw rod. One end of the air channel penetrates to the lower end face of the screw rod and is connected to the air outlet, and the other end penetrates to the side of the screw rod.

5. A transformer compensation type spring clamping device according to claim 3, characterized in that, A limiting groove is provided at the upper end of the sleeve. The lower end of the screw rod extends into the limiting groove and abuts against the bottom of the limiting groove.

6. A transformer compensation type spring clamping device according to claim 1, characterized in that, The spring adopts a disc spring, and multiple disc springs are stacked up and down in the sleeve.

7. A transformer compensation type spring clamping device according to claim 3, characterized in that, The locking member further includes an upper nut, and the upper nut is screwed tightly on the screw rod to press the upper side of the clamping plate.

8. A transformer compensation type spring clamping device according to claim 7, characterized in that, When installing the spring pressing device, after assembling the base, the spring and the sleeve, the base is abutted against the upper side of the coil. The screw rod passes through the clamping plate through the installation hole. The lower nut is screwed into the lower end of the screw rod and presses the screw rod downward. The lower end of the screw rod presses the coil through the sleeve, the spring and the base. When the compression amount of the spring reaches the target value, the screw rod continues to move downward a distance d, where 0.1 mm < d < 0.5 mm. After the lower nut is rotated upward to abut against the lower side of the clamping plate, the screw rod is released. The lower nut presses the lower side of the clamping plate. Finally, the upper nut is tightened on the screw rod.

Images