A large motor stator end coil winding vacuum potting device and method

Abstract

The present application relates to a kind of large motor stator end coil winding vacuum potting device and method, motor stator includes core and coil winding, including inner side and tight ring and outer fixed ring, inner side and tight ring is achieved with the sealing fixed connection of core end inner wall by silica gel sealing connection component, outer fixed ring is formed with the upper end of inner side and tight ring through sealing cover plate and forms vacuum potting cavity;Silica gel sealing connection component includes silica gel sleeve and is set on the horizontal connecting portion on the outer side of silica gel sleeve connecting ring portion and horizontal circumferential extrusion group.This application has the following advantages: by improving the sealing of vacuum potting cavity and the concentricity of vacuum potting cavity and core, completely exclude the bubble residual of coil turn and layer, improve the electrical strength, bonding strength and impact resistance of insulating layer, avoid the internal stress concentration caused by the uneven shrinkage of insulating layer solidification due to concentricity deviation.

Description

Technical Field

[0001] This invention belongs to the field of motor insulation treatment, specifically relating to a vacuum potting device and method for the end coil winding of a large motor stator. Background Technology

[0002] In the high-end manufacturing process of large motors (such as high-power-density motors used in wind power generation, ship propulsion, and industrial transmission), the insulation treatment of the stator end coil windings is one of the core processes that determines the reliability, lifespan, and electrical performance of the motor. Vacuum potting technology has become the mainstream process for end insulation of high-end motors because it can completely eliminate air bubbles and achieve defect-free resin filling and curing. This process requires the construction of a sealed vacuum chamber at the end of the stator core to completely cover the exposed coil ends, and injecting high-performance resin (such as epoxy resin) in a vacuum environment. This resin impregnates the gaps between coil turns and the gaps between the coil and the core, ultimately curing to form a solid overall insulation structure.

[0003] An ideal potting system must simultaneously meet two core requirements: absolute sealing and high concentricity between the potting cavity and the stator core. Sealing is a prerequisite for vacuum processes; any leakage will result in residual bubbles or resin outflow. Bubbles, under a high-voltage electric field, become the starting point for partial discharge, significantly reducing the partial discharge initiation voltage of the insulator and shortening its lifespan. Simultaneously, insufficient inter-turn bonding strength at the cured coil ends may induce more severe inter-turn short circuits under strong electromagnetic forces. Concentricity directly determines the uniformity of the potting layer thickness, the stress distribution at the coil ends, and the roundness of the stator inner hole after potting, thus affecting the ease of subsequent rotor assembly and the uniformity of the air gap during motor operation.

[0004] However, achieving both objectives simultaneously in existing technologies faces significant technical contradictions and challenges. Firstly, existing sealing devices typically rely on static sealing rings (such as O-rings) placed between rigid metal parts, or on auxiliary materials like silicone sealant. These passive sealing methods demand extremely high precision in the machining and geometric tolerances of the mating surfaces. For large motor stators, the core is constructed from a large number of stacked silicon steel sheets, inevitably resulting in manufacturing errors such as waviness, taper, and ellipticity on the inner wall. When the rigid mold core is inserted into the core's inner hole, an interference fit is often required to ensure a seal, but this causes the mold core and core axis to deviate, disrupting concentricity. If a clearance fit is used to ensure concentricity, the sealing ring compression is insufficient to compensate for the irregular tolerances of the inner wall, easily leading to leakage. Therefore, the tight contact required for sealing and the axial alignment required for concentricity create a natural conflict in rigid connection structures.

[0005] Secondly, existing devices lack an adjustment mechanism capable of simultaneously achieving radial active clamping and automatic centering. Most designs rely solely on axial bolt locking, indirectly compressing the sealing element, and cannot independently and uniformly adjust the radial pressure at the sealing interface. When there are local bulges or depressions on the inner wall of the core, the rigid mold core cannot adaptively compensate, resulting in severely uneven distribution of sealing pressure. This can lead to leakage or damage to the core due to local overstress. More critically, the concentricity of the potting chamber depends entirely on the machining reference of the core's inner hole, lacking independent centering correction capability. Once there is a deviation in the core's inner hole, the potting layer will exhibit an eccentric distribution—insufficient insulation strength on the thin-walled side and high internal stress due to curing shrinkage on the thick-walled side. This can easily lead to cracks during long-term operation, and even cause insulation breakdown or end vibration fatigue failure. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a vacuum potting device and method for the stator end coil winding of a large motor. By improving the sealing performance of the vacuum potting cavity and the concentricity between the vacuum potting cavity and the iron core, the residual air bubbles between coil turns and layers are completely eliminated, the electrical strength, bonding strength and impact resistance of the insulation layer are improved, and the internal stress concentration caused by uneven curing shrinkage of the insulation layer due to concentricity deviation is avoided.

[0007] The objective of this invention is achieved through the following technical solution: a vacuum potting device for the end coil winding of a large motor stator, wherein the motor stator includes an iron core and a coil winding, including an inner tightening ring and an outer fixing ring, the inner tightening ring is sealed and fixedly connected to the inner wall of the end of the iron core through a silicone sealing connection assembly, the outer fixing ring is sealed and fixedly connected to the end of the iron core, and the upper ends of the outer fixing ring and the inner tightening ring form a vacuum potting cavity through a sealing cover plate, and the end of the coil winding is placed in the vacuum potting cavity; The inner tightening ring includes an inner ring portion, a horizontal connecting portion located on the lower end face of the inner ring portion, and a silicone sleeve connecting ring portion located on the lower end of the horizontal connecting portion; The silicone sealing connection assembly includes a silicone sleeve fitted on the outside of the silicone sleeve connecting ring and a horizontal circumferential extrusion assembly set on the horizontal connecting part. The outer diameter of the lower end face of the silicone sleeve is smaller than the outer diameter of the upper end face, so that when the inner tightening ring moves from top to bottom, the outer wall of the silicone sleeve and the inner wall of the iron core are squeezed against each other to achieve a sealing contact. At the same time, the horizontal circumferential extrusion assembly performs horizontal circumferential pressing on the inner wall of the silicone sleeve, so that the silicone sleeve and the inner tightening ring are tightly connected.

[0008] A further improvement of the present invention is that: the horizontal circumferential extrusion assembly includes a plurality of first extrusion blocks and a plurality of second extrusion blocks disposed on the horizontal connecting part. Each first extrusion block and each second extrusion block are evenly and alternately distributed in the circumferential direction on the inner ring of the silicone sleeve, and are adjusted by independent screws to apply horizontal circumferential extrusion force to the silicone sleeve.

[0009] A further improvement of the present invention is that: the horizontal connecting part has a placement groove for embedding a plurality of first extrusion blocks and second extrusion blocks, and the side of the placement groove near the silicone sleeve is a through hole. The first extrusion blocks and second extrusion blocks can move along the through hole and extrude the inner wall of the silicone sleeve under the drive of their respective screws.

[0010] A further improvement of the present invention is that: the first extrusion block includes a first arc-shaped strip that is in close contact with the inner wall of the silicone sleeve and a first connecting frame that is fixedly connected to the first arc-shaped strip, the first connecting frame being threadedly connected to a corresponding screw; the second extrusion block includes an embedding part that is embedded between two adjacent first arc-shaped strips and a second arc-shaped strip that is fixedly disposed on the end face of the embedding part, the end face of the second arc-shaped strip away from the embedding part being fixedly connected to a second connecting frame, the second connecting frame being threadedly connected to a corresponding screw.

[0011] A further improvement of the present invention is that: the plurality of first arc-shaped strips and the plurality of embedded parts surround to form a ring-shaped structure, and the outer end face of the second arc-shaped strip abuts against the inner wall of the end of two adjacent first arc-shaped strips.

[0012] A further improvement of the present invention is that: the inner wall of the silicone sleeve has a first rib, the outer wall of the silicone sleeve has a second rib, the outer wall of the connecting ring of the silicone sleeve has a first limiting groove that cooperates with the first rib, and the outer end face of the first arc-shaped strip and the embedded part has a second limiting groove that cooperates with the second rib.

[0013] A further improvement of the present invention is that it also includes a leveling base and a support column. The leveling base and the support column are integrally formed. The two sides of the leveling base are fixedly connected to the lower end face of the iron core. The support column is placed in the center of the leveling base and vertically penetrates the central hole of the iron core, and contacts the center of the lower end face of the horizontal connecting part to support the inner tightening ring.

[0014] A further improvement of the present invention is that: the leveling base includes a lower support ring and an upper support ring, the lower end of the support column is fixedly connected to the center of the lower support ring, the upper end of the lower support ring has an outwardly protruding ring-shaped ear plate one, the upper and lower ends of the upper support ring have outwardly protruding ring-shaped ear plates two and three respectively, the lower end of the outer fixing ring has an outwardly protruding ring-shaped ear plate four, ear plate one and ear plate three are fixedly connected accordingly, ear plate two and ear plate four are fixedly connected accordingly, and the upper support ring covers the outer circumference of the iron core.

[0015] A further improvement of the present invention is that: the sealing cover plate has a pressure gauge, a vacuum extraction port and a glue injection port, and the sealing cover plate also has a transparent observation port; the vacuum extraction port is connected to a vacuum pump through a vacuum tube, and the vacuum tube has a vacuum valve; the glue injection port is connected to a glue supply tank through a glue supply pipe, and the glue supply pipe has a glue dispensing valve; the inner walls of the inner tightening ring and the outer fixing ring have a release coating.

[0016] A vacuum potting method for the stator end coil windings of a large electric motor, comprising the following steps: S1. Positioning the motor stator: The upper support ring is fitted onto the outside of the iron core of the motor stator. The iron core with the upper support ring is placed vertically on the lower support ring. The ear plate three of the upper support ring corresponds vertically to the ear plate one on the lower support ring and is fixed with bolts. At this time, the end of the coil winding to be potted faces upward. S2. Install the inner tightening ring and the outer fixing ring: Install the inner tightening ring from top to bottom to the inner wall of the iron core, so that the outer wall of the silicone sleeve and the inner wall of the iron core are in sealed and tight contact until the horizontal connection part contacts the support column. At this time, the outer wall surface of the silicone sleeve and the inner wall of the iron core are squeezed against each other to achieve a sealed contact. Install the outer fixing ring to the upper end face of the iron core, so that the ear plate four on the outer fixing ring and the ear plate two on the upper support ring are vertically aligned and fixedly connected by bolts to ensure that the inner tightening ring and the outer fixing ring are concentrically set. S3. Horizontal circumferential tightening of silicone sleeve: Rotate the screw connected to the first extrusion block to make the first arc strip press against the inner wall of the silicone sleeve; rotate the screw connected to the second extrusion block to make the embedded part press against the inner wall of the silicone sleeve, while the end of the second arc strip presses against the end of the corresponding first arc strip to complete the circumferential locking of the silicone sleeve. S4. Forming a vacuum potting cavity: Install a sealing cover plate on the top of the inner tightening ring and the outer fixing ring to form a glue injection chamber. Vacuum the glue injection chamber to form a vacuum potting cavity inside the glue injection chamber. S5. Resin slurry base: Inject resin slurry into the injection chamber under vacuum, turn off the vacuum pump and vacuum valve, and open the injection metering valve. Because the supply tank is at normal pressure, a pressure difference is formed with the negative pressure in the vacuum potting chamber, and the resin slurry flows from the supply tank to the vacuum potting chamber. S6. Curing and Molding: The stator and vacuum potting device are placed in an autoclave and heated to allow the resin slurry to gel and cure, forming a dense resin potting layer on the outer wall of the coil winding. After curing, the coil winding is allowed to cool naturally, and the vacuum potting device is removed and demolded. The coil winding at the other end of the iron core that is not potted is vacuum potted again according to the above steps.

[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention solves the fundamental contradiction between the sealing of the vacuum filling cavity and the incompatibility between the vacuum filling cavity and the iron core, and achieves self-adaptive sealing of the inner hole of the iron core and coaxial alignment between the vacuum filling cavity and the iron core. On the one hand, a tapered silicone sleeve with a gradually decreasing outer diameter at the lower end is used as an adaptive elastic sealing element. When the inner tightening ring is placed vertically downward, the outer conical surface of the silicone sleeve naturally forms radial compression with the inner hole wall of the iron core. The high elasticity of the silicone material allows it to actively conform to the local unevenness, misalignment, and shape tolerances of the inner wall of the iron core, ensuring that the sealing contact pressure is evenly distributed along the irregular contour. This achieves a reliable vacuum seal while completely eliminating the risk of local overload of the iron core and damage to the silicon steel sheets caused by rigid extrusion. On the other hand, the horizontal circumferential extrusion group consists of multiple first extrusion blocks and multiple second extrusion blocks that are evenly distributed alternately along the circumference. The corresponding extrusion blocks are adjusted sequentially by a screw, causing them to radially push and extrude the inner wall of the silicone sleeve. When the multiple extrusion blocks are adjusted into place, the end of the second arc-shaped strip of the second extrusion block exactly abuts against the end of the adjacent first arc-shaped strip, so that the multiple first extrusion blocks and multiple second extrusion blocks are connected end to end and interlocked in the circumferential direction, connecting all the originally discrete independent radial forces into a closed and continuous circumferential pressure ring. This closed-loop self-locking structure provides uninterrupted and uniform radial support to the silicone sleeve throughout its 360° circumference, completely eliminating any gaps in sealing pressure that may exist between the individual extrusion blocks. The elastic self-adaptation of the silicone sleeve, combined with the closed-loop locking of the extrusion group, reliably achieves high-vacuum sealing while fully preserving the radial floating centering capability of the inner top ring provided by the elastic layer. This fundamentally resolves the inherent contradiction between sealing and concentricity, resulting in a dense, pore-free insulation layer with uniform thickness throughout its circumference. This optimizes the electric field distribution, significantly reduces the risk of partial discharge, and fully guarantees the bonding strength between the winding and the core. Consequently, it fundamentally improves the long-term reliability and service life of the motor end winding insulation. 2. This invention further achieves concentricity between the stator core and the vacuum potting cavity through the setting of a leveling base and a support column. The leveling base is fixed to the lower end face of the core, and the support column at its center vertically penetrates the central hole of the core. When the inner tightening ring is installed in place, the center of the lower end face of its horizontal connection is precisely located on the top of the support column. This structure establishes an independent centering benchmark with the axis of the inner tightening ring strictly coinciding with the theoretical central axis of the core. The final position of the inner tightening ring is completely determined by the support column, and is completely separated from the irregular shape of the inner wall of the core. At the same time, the outer fixing ring is covered and fixed to the outer circle of the core through the positioning connection of the upper and lower support rings and multi-layer ear plates, ensuring that the outer ring and the inner ring are coaxial in height. As a result, the vacuum potting cavity formed is completely concentric with the theoretical center of the coil end, and the formed insulating potting layer has a uniform thickness in the entire 360° direction, avoiding the problems of insufficient insulation strength in thin-walled areas and stress concentration due to curing shrinkage in thick-walled areas. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a vacuum potting device for the end of a large motor stator core according to the present invention.

[0019] Figure 2 for Figure 1 Internal structural cross-sectional view.

[0020] Figure 3 for Figure 2 An enlarged schematic diagram of structure A in the middle.

[0021] Figure 4 for Figure 2 A schematic diagram showing the connection between the horizontal circumferential extrusion assembly and the inner tightening ring.

[0022] Figure 5 for Figure 1 A schematic diagram showing the positions of the horizontal circumferential extrusion assembly and the silicone sleeve.

[0023] Figure 6 for Figure 5 A schematic diagram showing the connection between the first extrusion block and the second extrusion block.

[0024] The numbers in the diagram are: 1-iron core, 2-coil winding, 3-inner tightening ring, 4-outer fixing ring, 5-silicone sealing connection assembly, 6-sealing cover plate, 7-vacuum potting cavity, 8-leveling base, 9-support column, 10-pressure gauge, 11-vacuum extraction port, 12-glue injection port, 13-transparent observation port; 31-Inner ring, 32-Horizontal connecting part, 33-Silicone sleeve connecting ring, 34-Placement groove, 35-Through hole; 51-Silicone sleeve, 52-Horizontal circumferential extrusion assembly, 53-First rib, 54-Second rib, 55-First limiting groove, 56-Second limiting groove; 521-First extrusion block, 522-Second extrusion block, 523-Screw, 524-First arc-shaped strip, 525-First connecting frame, 526-Embedded part, 527-Second arc-shaped strip, 528-Second connecting frame; 81-Lower support ring, 82-Upper support ring, 83-Ear plate one, 84-Ear plate two, 85-Ear plate three, 86-Ear plate four. Detailed Implementation

[0025] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0026] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship, such as those based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, and therefore should not be construed as a limitation of this invention.

[0027] A vacuum potting device for the stator end coil windings of a large electric motor, as described in the reference. Figure 1 , Figure 2 The motor stator includes an iron core 1 and a coil winding 2, including an inner tightening ring 3 and an outer fixing ring 4. The inner tightening ring 3 is sealed and fixed to the inner wall of the end of the iron core 1 through a silicone sealing connection assembly 5. The outer fixing ring 4 is sealed and fixed to the end of the iron core 1. The upper ends of the outer fixing ring 4 and the inner tightening ring 3 form a vacuum potting cavity 7 through a sealing cover plate 6. The end of the coil winding 2 is placed in the vacuum potting cavity 7. The inner tightening ring 3 includes an inner ring portion 31, a horizontal connecting portion 32 located on the lower end face of the inner ring portion 31, and a silicone sleeve connecting ring portion 33 located on the lower end of the horizontal connecting portion 32. The silicone sealing connection assembly 5 includes a silicone sleeve 51 sleeved on the outside of the silicone sleeve connecting ring 33 and a horizontal circumferential extrusion assembly 52 disposed on the horizontal connecting part 32. The outer diameter of the lower end face of the silicone sleeve 51 is smaller than the outer diameter of the upper end face, so that when the inner tightening ring 3 moves from top to bottom, the outer wall of the silicone sleeve 51 and the inner wall of the iron core 1 are pressed against each other to achieve a sealing contact between the two. At the same time, the horizontal circumferential extrusion assembly 52 performs horizontal circumferential pressing on the inner wall of the silicone sleeve 51, so that the silicone sleeve 51 and the inner tightening ring 3 are tightly connected.

[0028] Based on this embodiment, refer to Figures 3 to 6 The horizontal circumferential extrusion assembly 52 includes a plurality of first extrusion blocks 521 and a plurality of second extrusion blocks 522 disposed on the horizontal connecting part 32. Each first extrusion block 521 and each second extrusion block 522 are evenly distributed alternately along the circumferential direction on the inner ring of the silicone sleeve 51, and are adjusted by independent screws 523 to apply horizontal circumferential extrusion force to the silicone sleeve 51.

[0029] Based on this embodiment, the horizontal connecting part 32 has a placement groove 34 for embedding a plurality of first extrusion blocks 521 and second extrusion blocks 522. The side of the placement groove 34 near the silicone sleeve 51 is a through hole 35. Under the drive of their respective screws 523, the first extrusion blocks 521 and second extrusion blocks 522 can move along the through hole 35 and extrude the inner wall of the silicone sleeve 51.

[0030] Based on this embodiment, the first extrusion block 521 includes a first arc-shaped strip 524 that is in close contact with the inner wall of the silicone sleeve 51 and a first connecting frame 525 that is fixedly connected to the first arc-shaped strip 524. The first connecting frame 525 is threadedly connected to the corresponding screw 523. The second extrusion block 522 includes an embedding part 526 embedded between two adjacent first arc-shaped strips 524 and a second arc-shaped strip 527 fixedly disposed on the end face of the embedding part 526. The end face of the second arc-shaped strip 527 away from the embedding part 526 is fixedly connected to the second connecting frame 528. The multiple first arc-shaped strips 524 and the multiple embedding parts 526 surround to form a ring-shaped structure. The outer end face of the second arc-shaped strip 527 abuts against the inner wall of the end of two adjacent first arc-shaped strips 524. The second connecting frame 528 is threadedly connected to the corresponding screw 523.

[0031] This invention solves the fundamental contradiction between the sealing of the vacuum filling cavity 7 and the incompatibility between the vacuum filling cavity 7 and the iron core 1, and achieves self-adaptive sealing of the inner hole of the iron core 1 and coaxial alignment between the vacuum filling cavity 7 and the iron core 1. On the one hand, a tapered silicone sleeve 51 with a gradually decreasing outer diameter at the lower end is used as an adaptive elastic sealing element. When the inner tightening ring 3 is placed vertically downward, the outer conical surface of the silicone sleeve 51 naturally forms radial compression with the inner hole wall of the iron core 1. The high elasticity of the silicone material can actively conform to the local unevenness, misalignment, and shape tolerance of the inner wall of the iron core 1, so that the sealing contact pressure is evenly distributed along the irregular contour. While achieving a reliable vacuum seal, it completely eliminates the risk of local overload of the iron core 1 and damage to the silicon steel sheets caused by rigid extrusion. On the other hand, the horizontal circumferential extrusion group 52 is composed of multiple first extrusion blocks 521 and multiple second extrusion blocks 522 that are evenly distributed in the circumferential direction. The corresponding extrusion blocks are adjusted in sequence by the screw 523, so that they push and extrude the inner wall of the silicone sleeve radially. When the multiple extrusion blocks are adjusted into place, the end of the second arc strip 527 of the second extrusion block 522 just abuts against the end of the adjacent first arc strip 524, so that the multiple first extrusion blocks 521 and multiple second extrusion blocks 522 are connected end to end in the circumferential direction and interlock with each other, connecting all the originally discrete independent radial forces into a closed and continuous circumferential pressure ring. This closed-loop self-locking structure ensures that the silicone sleeve receives uninterrupted and uniform radial support throughout its 360° circumference, completely eliminating any gaps in sealing pressure that may exist between the individual extrusion blocks. The elastic self-adaptation of the silicone sleeve 51, combined with the closed-loop locking of the horizontal circumferential extrusion group 52, reliably achieves high vacuum sealing while fully preserving the radial floating centering capability of the inner top ring provided by the elastic layer, thus fundamentally resolving the inherent contradiction between sealing and concentricity.

[0032] Secondly, the closed-loop locking structure of the horizontal circumferential extrusion group 52 provides a uniform radial pressure field, mechanically ensuring the automatic realization of the centering tendency. When all the first extrusion blocks 521 and the second extrusion blocks 522 are adjusted into position by independent screws and connected end to end to form a closed circumferential pressure ring, the radial clamping force on the silicone sleeve is continuous and uniformly distributed throughout the 360° circumference. If the inner clamping ring 3 is biased to one side, the silicone sleeve 51 on that side will be over-compressed, and the resulting elastic restoring force will increase; while the compression of the silicone sleeve 51 on the opposite side will decrease, and the restoring force will decrease accordingly. According to the principle of force balance, this non-uniform elastic restoring force field will generate a resultant force pointing towards the center, pushing the inner clamping ring 3 towards the position of minimum restoring force—that is, the center position where the compression in all directions of the circumference is equal—until the elastic forces in all directions are rebalanced. This automatic centering behavior is a spontaneous mechanical response of the elastic body under uniform external pressure, without the need for manual intervention.

[0033] It should be noted that the screw in this solution can be adjusted and driven by the corresponding geared motor, so that multiple first extrusion blocks and second extrusion blocks can synchronously and evenly extrude the silicone sleeve 51 on the lower end face of the inner pressing ring.

[0034] Based on this embodiment, the inner wall of the silicone sleeve 51 has a first rib 53, the outer wall of the silicone sleeve 51 has a second rib 54, the outer wall of the silicone sleeve connecting ring 33 has a first limiting groove 55 that cooperates with the first rib 53, and the outer end face of the first arc-shaped strip 524 and the embedding part 526 has a second limiting groove 56 that cooperates with the second rib 54.

[0035] The inner and outer walls of the silicone sleeve 51 are respectively provided with a first rib 53 and a second rib 54, which are respectively fitted into the first limiting groove 55 of the silicone sleeve connecting ring 33 and the second limiting groove 56 on the outer end face of the extrusion block, forming a bidirectional mechanical locking in both the axial and circumferential directions. This structure ensures that the silicone sleeve maintains a precise installation position and does not slip, flip, or bulge when subjected to radial thrust from the horizontal circumferential extrusion group and axial installation friction. The interference fit between the ribs and the grooves simultaneously eliminates the gap between the silicone sleeve 51 and the silicone sleeve connecting ring 33, eliminating potential leakage paths along the contact interface and ensuring precise and controllable transmission of sealing pressure.

[0036] Based on this embodiment, it also includes a leveling base 8 and a support column 9. The leveling base 8 and the support column 9 are integrally formed. The two sides of the leveling base 8 are fixedly connected to the lower end face of the iron core 1. The support column 9 is placed in the center of the leveling base 8 and vertically penetrates the center hole of the iron core 1, and contacts the center of the lower end face of the horizontal connecting part 32 to support the inner tightening ring 3.

[0037] This invention provides vertical and radial support to the inner tightening ring 3 through the support column 9 at the center of the leveling base 8, and provides vertical support and radial positioning reference for the inner tightening ring 3. This reference is independent of the geometric center of the inner hole of the iron core 1. The inner tightening ring 3 can float radially within the elastic layer of the silicone sleeve 51. During the pressure application process of the horizontal circumferential extrusion group 52, the final stable position is the result of the combined action of the elastic force field balance point and the positioning reference of the support column 9, which further realizes the coaxial alignment of the inner hole of the iron core 1 and the vacuum potting cavity 7, fundamentally avoiding the transmission of iron core lamination error to the eccentricity of the vacuum potting layer.

[0038] Among them, reference Figure 1 The leveling base 8 includes a lower support ring 81 and an upper support ring 82. The lower end of the support column 9 is fixedly connected to the center of the lower support ring 81. The upper end of the lower support ring 81 has an outwardly protruding ring-shaped ear plate 1 83. The upper and lower ends of the upper support ring 82 have outwardly protruding ring-shaped ear plates 2 84 and 3 85, respectively. The lower end of the outer fixing ring 4 has an outwardly protruding ring-shaped ear plate 4 86. Ear plate 1 83 and ear plate 3 85 are fixedly connected accordingly, and ear plate 2 84 and ear plate 4 86 are fixedly connected accordingly. The upper support ring 82 covers the outer circumference of the iron core 1.

[0039] The sealing cover plate 6 has a pressure gauge 10, a vacuum extraction port 11, and a glue injection port 12. The sealing cover plate 6 also has a transparent observation port 13. The vacuum extraction port 11 is connected to a vacuum pump through a vacuum tube, which has a vacuum valve. The glue injection port 12 is connected to a glue supply tank through a glue supply pipe, which has a glue injection metering valve. The inner walls of the inner tightening ring 3 and the outer fixing ring 4 have a release coating.

[0040] A vacuum potting method for the stator end coil windings of a large electric motor, comprising the following steps: S1. Positioning the motor stator: The upper support ring is fitted onto the outside of the iron core of the motor stator. The iron core with the upper support ring is placed vertically on the lower support ring. The ear plate three of the upper support ring corresponds vertically to the ear plate one on the lower support ring and is fixed with bolts. At this time, the end of the coil winding to be potted faces upward. S2. Install the inner tightening ring 3 and the outer fixing ring 4: Install the inner tightening ring 3 from top to bottom to the inner wall of the iron core 1, so that the outer wall of the silicone sleeve 51 is in sealed and tight contact with the inner wall of the iron core 1, until the horizontal connecting part 32 contacts the support column 9. At this time, the outer wall surface of the silicone sleeve 51 and the inner wall of the iron core 1 are squeezed against each other to achieve a sealed contact. Install the outer fixing ring 4 to the upper end face of the iron core 1, so that the ear plate 4 86 on the outer fixing ring 4 corresponds vertically to the ear plate 2 84 on the upper support ring 82 and is fixedly connected by bolts to ensure that the inner tightening ring 3 and the outer fixing ring 4 are concentrically set. S3. Horizontally tighten the silicone sleeve 51: Rotate the screw 523 connected to the first extrusion block 521 to make the first arc-shaped strip 524 press against the inner wall of the silicone sleeve 51; rotate the screw 523 connected to the second extrusion block 522 to make the embedded part 526 press against the inner wall of the silicone sleeve 51, and at the same time, the end of the second arc-shaped strip 527 presses against the end of the corresponding first arc-shaped strip 524 to complete the circumferential locking of the silicone sleeve 51. S4. Forming a vacuum potting cavity: Install a sealing cover plate 6 on the top of the inner tightening ring 3 and the outer fixing ring 4 to form a glue injection chamber. Vacuum the glue injection chamber to form a vacuum potting cavity 7 inside the glue injection chamber. S5. Resin slurry base: Inject resin slurry into the injection chamber under vacuum environment, turn off the vacuum pump and vacuum valve, and open the injection metering valve. Because the supply tank is at normal pressure, a pressure difference is formed with the negative pressure in the vacuum potting chamber, and the resin slurry flows from the supply tank to the vacuum potting chamber 7. S6. Curing and molding: The stator and vacuum potting device are placed in an autoclave and heated to allow the resin slurry to gel and solidify, forming a dense resin potting layer on the outer wall of the coil winding 2. After curing, the coil winding 2 is allowed to cool naturally and the vacuum potting device is removed and demolded. The coil winding 2 at the other end of the iron core that is not potted is vacuum potted again according to the above steps.

[0041] This invention, through the synergistic effect of independent centering reference and flexible adaptive sealing, ensures the molding quality and comprehensive performance of the potting insulation layer. Specifically, the design of the silicone sleeve conical surface and the setting of the horizontal circumferential extrusion group 52 guarantee absolute vacuum inside the vacuum potting cavity, completely eliminating residual air bubbles between coil turns and layers. This results in a dense and flawless insulation layer after molding, significantly improving the partial discharge initiation voltage and dielectric strength, and eliminating the hidden danger of partial discharge caused by air bubbles under a high-voltage electric field. A high-strength adhesive interface is formed between the resin and the coil windings and iron core. Under the repeated action of the strong impact electromagnetic force of the motor, there is no loosening or vibration wear between turns, fundamentally eliminating short-circuit faults between turns. Moreover, the concentric centering structure composed of the support column and multiple ear plates ensures absolute uniformity of the thickness of the vacuum potting layer throughout its circumference, eliminating weak insulation at thin-walled areas and internal stress concentration caused by uneven curing shrinkage at thick-walled areas. This effectively prevents cracking or fatigue failure of the insulation layer, achieving a leap in the long-term operating life of the motor end winding insulation.

[0042] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A vacuum potting device for the end coil windings of a large motor stator, wherein the motor stator comprises an iron core and coil windings, characterized in that: It includes an inner tightening ring and an outer fixing ring. The inner tightening ring is sealed and fixed to the inner wall of the iron core end through a silicone sealing connection assembly. The outer fixing ring is sealed and fixed to the iron core end. The upper ends of the outer fixing ring and the inner tightening ring form a vacuum potting cavity through a sealing cover plate. The end of the coil winding is placed in the vacuum potting cavity. The inner tightening ring includes an inner ring portion, a horizontal connecting portion located on the lower end face of the inner ring portion, and a silicone sleeve connecting ring portion located on the lower end of the horizontal connecting portion. The silicone sealing connection assembly includes a silicone sleeve fitted on the outside of the silicone sleeve connecting ring and a horizontal circumferential extrusion assembly disposed on the horizontal connecting part. The outer diameter of the lower end face of the silicone sleeve is smaller than the outer diameter of the upper end face, so that when the inner tightening ring moves from top to bottom, the outer wall of the silicone sleeve and the inner wall of the iron core are squeezed against each other to achieve a sealing contact between the two. At the same time, the horizontal circumferential extrusion assembly performs horizontal circumferential pressing on the inner wall of the silicone sleeve, so that the silicone sleeve and the inner tightening ring are tightly connected.

2. The vacuum potting device for the stator end coil winding of a large motor according to claim 1, characterized in that, The horizontal circumferential extrusion assembly includes multiple first extrusion blocks and multiple second extrusion blocks disposed on the horizontal connecting part. Each first extrusion block and each second extrusion block are evenly distributed alternately along the circumferential direction on the inner ring of the silicone sleeve, and are adjusted by independent screws to apply horizontal circumferential extrusion force to the silicone sleeve.

3. The vacuum potting device for the stator end coil winding of a large motor according to claim 2, characterized in that, The horizontal connecting part has a placement groove for embedding multiple first extrusion blocks and second extrusion blocks. The side of the placement groove near the silicone sleeve is a through hole. Driven by their respective screws, the first extrusion blocks and second extrusion blocks can move along the through hole and extrude the inner wall of the silicone sleeve.

4. The vacuum potting device for the stator end coil winding of a large electric motor according to claim 3, characterized in that, The first extrusion block includes a first arc-shaped strip that is in close contact with the inner wall of the silicone sleeve and a first connecting frame that is fixedly connected to the first arc-shaped strip. The first connecting frame is threadedly connected to the corresponding screw. The second extrusion block includes an embedding part that is embedded between two adjacent first arc-shaped strips and a second arc-shaped strip that is fixedly disposed on the end face of the embedding part. The end face of the second arc-shaped strip away from the embedding part is fixedly connected to the second connecting frame. The second connecting frame is threadedly connected to the corresponding screw.

5. The vacuum potting device for the stator end coil winding of a large electric motor according to claim 4, characterized in that, The plurality of first arc-shaped strips and the plurality of embedded parts surround to form a ring-shaped structure, and the outer end face of the second arc-shaped strip abuts against the inner wall of the ends of two adjacent first arc-shaped strips.

6. The vacuum potting device for the stator end coil winding of a large electric motor according to claim 5, characterized in that, The inner wall of the silicone sleeve has a first rib, the outer wall of the silicone sleeve has a second rib, the outer wall of the connecting ring of the silicone sleeve has a first limiting groove that cooperates with the first rib, and the outer end face of the first arc-shaped strip and the embedded part has a second limiting groove that cooperates with the second rib.

7. The vacuum potting device for the stator end coil winding of a large electric motor according to claim 6, characterized in that, It also includes a leveling base and a support column. The leveling base and the support column are integrally formed. The two sides of the leveling base are fixedly connected to the lower end face of the iron core. The support column is placed in the center of the leveling base and vertically penetrates the center hole of the iron core, and contacts the center of the lower end face of the horizontal connecting part to support the inner tightening ring.

8. The vacuum potting device for the stator end coil winding of a large motor according to claim 7, characterized in that, The leveling base includes a lower support ring and an upper support ring. The lower end of the support column is fixedly connected to the center of the lower support ring. The upper end of the lower support ring has an outwardly protruding ring-shaped ear plate one. The upper and lower ends of the upper support ring have outwardly protruding ring-shaped ear plates two and three, respectively. The lower end of the outer fixing ring has an outwardly protruding ring-shaped ear plate four. Ear plate one and ear plate three are fixedly connected to each other. Ear plate two and ear plate four are fixedly connected to each other. The upper support ring covers the outer circumference of the iron core.

9. The vacuum potting device for the stator end coil winding of a large motor according to claim 8, characterized in that: The sealing cover plate has a pressure gauge, a vacuum extraction port, and a glue injection port. The sealing cover plate also has a transparent observation port. The vacuum extraction port is connected to a vacuum pump through a vacuum tube, and the vacuum tube has a vacuum valve. The glue injection port is connected to a glue supply tank through a glue supply pipe, and the glue supply pipe has a glue dispensing valve. The inner walls of the inner tightening ring and the outer fixing ring have a release coating.

10. A method for vacuum potting the stator end coil winding of a large electric motor as described in claim 9, characterized in that, The specific steps include: S1. Positioning the motor stator: The upper support ring is fitted onto the outside of the iron core of the motor stator. The iron core with the upper support ring is placed vertically on the lower support ring. The ear plate three of the upper support ring corresponds vertically to the ear plate one on the lower support ring and is fixed with bolts. At this time, the end of the coil winding to be potted faces upward. S2. Install the inner tightening ring and the outer fixing ring: Install the inner tightening ring from top to bottom to the inner wall of the iron core, so that the outer wall of the silicone sleeve and the inner wall of the iron core are in sealed and tight contact until the horizontal connection part contacts the support column. At this time, the outer wall surface of the silicone sleeve and the inner wall of the iron core are squeezed against each other to achieve a sealed contact. Install the outer fixing ring to the upper end face of the iron core, so that the ear plate four on the outer fixing ring and the ear plate two on the upper support ring are vertically aligned and fixedly connected by bolts to ensure that the inner tightening ring and the outer fixing ring are concentrically set. S3. Horizontal circumferential tightening of silicone sleeve: Rotate the screw connected to the first extrusion block to make the first arc strip press against the inner wall of the silicone sleeve; rotate the screw connected to the second extrusion block to make the embedded part press against the inner wall of the silicone sleeve, while the end of the second arc strip presses against the end of the corresponding first arc strip to complete the circumferential locking of the silicone sleeve. S4. Forming a vacuum potting cavity: Install a sealing cover plate on the top of the inner tightening ring and the outer fixing ring to form a glue injection chamber. Vacuum the glue injection chamber to form a vacuum potting cavity inside the glue injection chamber. S5. Resin slurry base: Inject resin slurry into the injection chamber under vacuum, turn off the vacuum pump and vacuum valve, and open the injection metering valve. Because the supply tank is at normal pressure, a pressure difference is formed with the negative pressure in the vacuum potting chamber, and the resin slurry flows from the supply tank to the vacuum potting chamber. S6. Curing and Molding: The stator and vacuum potting device are placed in an autoclave and heated to allow the resin slurry to gel and cure, forming a dense resin potting layer on the outer wall of the coil winding. After curing, the coil winding is allowed to cool naturally, and the vacuum potting device is removed and demolded. The coil winding at the other end of the iron core that is not potted is vacuum potted again according to the above steps.

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