Stator bar end 3D transposition insulation filling forming process

Abstract

The invention relates to a stator bar end 3D transposition insulation filling molding process, which comprises the following steps: S1, braiding and winding flat copper wires: arranging a plurality of strands of flat copper wires into two columns, enabling each strand of wire to sequentially span from one column to the other column twice at the same interval, and arranging and distributing 3D transposition positions on the plurality of strands of flat copper wires on two side end surfaces at equal intervals; s2, extrusion molding of mica mud: mixing an adhesive and mica powder, and extruding the mixture into the mica mud; s3, mica mud is positioned, specifically, the mica mud is glued to the end faces of the two sides of the wire rod blank, the isolating membrane is peeled off, and a gasket containing an adhesive layer is arranged between the flat copper wires in a cushioned mode; s4, wrapping with a high-temperature-resistant film; s5, the positioning mold is embedded; s6, high-temperature and high-pressure forming; and S7, discharging and cooling. The method has the following advantages that the problem of pit filling generated by 3D transposition deflection winding of the motor coil is effectively solved, so that internal circulation generated by magnetic induction of the coil is stabilized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of motor insulation materials, and particularly relates to a stator bar end 3D transposition insulation filling forming process. BACKGROUND

[0002] Most of the existing motor coils, especially the stator coils of large motors such as steam turbine generators, are manufactured by using multi-strand wire transposition forming, and the flat copper wires in each row are transposed and wound according to a specific rule (a 3D transposition recess is formed at the end), so as to suppress the internal circulating current generated by the different magnetic induction of each part, and thus a transposition recess is formed, which cannot be directly wrapped with main insulation, and the transposition recess must be filled first.

[0003] The traditional stator bar transposition filling material is first made by impregnating mica paper with tung oil and then laminating and hot pressing to a certain thickness, and then developed into mica paper impregnated with epoxy resin to make a filling material with the required thickness.

[0004] The filling material after impregnating the mica paper has many shortcomings in performance and coil manufacturing process, for example, the filling material of tung oil mica paper system can only reach 130 DEG C at the highest glass transition temperature. Because the glass transition temperature is low, when the coil is wound with mica tape, anti-clouding tape and other VPI impregnated resin secondary forming, the curing temperature is 170 DEG C, and the internal cavity of the manufactured coil often appears, and the filling material is not heat-resistant enough to cause the product failure rate to increase.

[0005] Moreover, the filling material of mica paper system will appear phase separation when hot-pressed at high temperature, although the mica paper will be crushed at high temperature and will move with the resin, but for a coil with a length of 5 meters or even longer, the recess dead angle will appear at the position with large transposition angle, and the mica paper cannot completely fill the recess because it cannot flow freely, which greatly affects the insulation performance of the coil. During the filling and hot-pressing forming process of the coil, the resin has good fluidity, while the mica paper does not, which often causes the resin to seep out of the mica paper and flow to the side of the coil, affecting the size processing of the coil. In addition, during the manufacturing process of the mica paper filling material, there will be solvent residues when the mica paper is impregnated with resin, and the volatile matter often remains inside during the filling and forming process to produce bubbles affecting the insulation performance of the coil.

[0006] Therefore, the development of the mica mud motor coil filling insulation material makes up for the shortcomings of the previous filling materials in performance and application process. SUMMARY

[0007] The purpose of the present application is to overcome the above shortcomings, provide a stator bar end 3D transposition insulation filling forming process, effectively solve the recess filling caused by the 3D transposition of the motor coil, and suppress the internal circulating current generated by the magnetic induction of the coil.

[0008] The purpose of the present application is achieved by the following technical solutions: a stator bar end 3D transposition insulation filling forming process, comprising S1, flat copper wire winding: a plurality of flat copper wires are arranged in two rows, and each wire is crossed from one row to the other row twice with the same interval, and the 3D transposition positions on the plurality of flat copper wires are arranged in equal intervals on the two side end faces, so as to form a bar blank; S2, extruding mica mud: the adhesive and mica powder are mixed and extruded into mica mud; S3, positioning mica mud: the mica mud is adhered to the two side end faces of the bar blank, the release film is peeled off, and the gasket containing the adhesive layer is placed between the flat copper wires; S4, wrapping high-temperature-resistant film: the high-temperature-resistant film is wrapped and fixed outside the bar blank to form a unified whole; S5, embedding positioning mold: the bar blank is embedded in the positioning mold, the end of the bar blank protrudes from the end of the positioning mold, and the adhesive tape is wound outside the positioning mold to clamp and position the bar blank in the positioning mold; S6, high-temperature and high-pressure forming: the positioning mold containing the bar blank is placed in a hot press tank, 125±5℃ is added to half pressure and heat preservation and pressure preservation for 20-30min, and the temperature is stepped up to 165±5℃ to add full pressure and pressure preservation for solidification, the temperature and pressure are in the range of 100-165℃ and 0.3-0.6MPa, at this time, the mica mud flows at high temperature, without generating small molecule volatile substances, so that the bar blank and the mica mud on the side end form an integral whole, and the recess at the 3D transposition position on the outside of the bar blank is filled; S7, discharging and cooling: the bar blank is taken out of the hot press tank, the positioning mold is removed, and the high-temperature-resistant film outside the bar blank is peeled off, and the bar blank is naturally cooled, so that the side end transposition winding insulation filling forming is completed.

[0009] The further improvement of the present application is that step S2 comprises, a, selecting modified high-temperature-resistant epoxy resin 100-120 parts, aromatic amine-based curing agent 30-50 parts, and latent accelerator 1-3 parts by weight, and mixing to form an adhesive; b, the adhesive and mica powder are sent into a mixer to be pre-mixed into a lump, and the lump is repeatedly extruded to be shaped into a uniform body; c, the mixing equipment is extruded into an infinite long strip-shaped mica mud with different widths and thicknesses, and finally the mica mud is attached with a release film to be wound into a disc-shaped or long strip-shaped.

[0010] The further improvement of the present application is that the adhesive content of the long strip-shaped mica mud prepared in step S2 is 30%-40%, and the specific gravity is 1.6-1.9 g / cm3 , normal bonding strength ≥ 15.3 MPa, volume resistivity ≥ 1.0 x 10 15 Ω·cm, glass transition temperature ≥ 175℃.

[0011] The further improvement of the present application is that in step S4, the high-temperature-resistant film is fixed on the outside of the wire rod blank by being wrapped and fixed by the adhesive tape.

[0012] The further improvement of the present application is that the positioning mold comprises an upper mold and a lower mold, the upper mold and the lower mold are spliced to form a rectangular structure, and the upper mold and the lower mold have a rectangular cavity for embedding the wire rod blank.

[0013] The further improvement of the present application is that the upper mold and the lower mold each comprise an L-shaped body, the L-shaped body comprises a vertical portion and a horizontal portion, one end of the horizontal portion has a stepped portion inside, the vertical portion of the upper mold is matched with the stepped portion of the lower mold, and the vertical portion of the lower mold is matched with the stepped portion of the upper mold.

[0014] The further improvement of the present application is that the radial length of the rectangular cavity formed by the matching of the upper mold and the lower mold is consistent with the width of the wire rod blank, and the height of the rectangular cavity formed by the matching of the upper mold and the lower mold is consistent with the height of the wire rod blank.

[0015] Compared with the prior art, the present application has the following advantages: 1. In the present application, special mica mud is used, which is pre-mixed into a group, repeatedly extruded and mixed, so that the epoxy adhesive and the mica powder mixture reach a uniform phase, and finally extruded into a shape. The molding and use principle of the mica mud utilizes the temperature difference effect. At room temperature, the mica mud can maintain a certain shape as a plastic material, and can be shaped into any shape under high temperature and high pressure, thereby filling the pits generated at the 3D transposition of the motor coil, and finally curing and setting into an irreversible solidified material at high temperature, so as to suppress the internal circulation generated by the coil magnetic induction and ensure the insulation performance of the motor coil.

[0016] 2. In the present application, the mica mud does not volatilize solvent, and there are no small molecule volatiles under high temperature and high pressure, so that no volatiles are generated when the coil is filled and formed, effectively ensuring the insulation of the coil. Since the mica mud has no any reinforcing material for support, the physical properties of the solidified material depend entirely on the organic combination of the epoxy resin and the mica mud. The glass transition temperature of the mica solidified material can reach more than 175℃, and has good heat resistance and mechanical properties. When the motor coil is subjected to secondary heat forming in the later period, the coil inside is not empty, and the product failure rate caused by the insufficient heat resistance of the filling material is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a side view of the wire rod blank in step S1 of the present application.

[0018] Figure 2 The top view of the wire rod blank in step S1 of the present application.

[0019] Figure 3 The structure schematic diagram of the wire rod blank in the present application after positioning mica mud and wrapping high-temperature-resistant film.

[0020] Figure 4 The structure schematic diagram of the positioning mold in the present application.

[0021] Figure 5 The structure schematic diagram of the upper mold or the lower mold in the positioning mold in the present application.

[0022] Reference numerals in the drawing: 1-wire rod blank, 2-mica mud, 3-high-temperature-resistant film, 4-positioning mold; 41-upper mold, 42-lower mold, 43-rectangular cavity; 441-L-shaped body, 442-vertical part, 443-horizontal part, 444-step part. DETAILED DESCRIPTION

[0023] In order to deepen the understanding of the present application, the present application will be further described in combination with the embodiments and the accompanying drawings, which are only used to explain the present application and do not constitute the limitation to the protection scope of the present application.

[0024] In the description of the present application, it should be understood that the terms indicating the orientation or position relationship, such as the orientation or position relationship based on the drawing, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, and therefore cannot be understood as the limitation to the present application.

[0025] In the present application, unless otherwise explicitly specified and limited, the terms such as “connection”, “provided with”, “have” should be understood in a broad sense, for example, it can be fixed connection, detachable connection, or integral connection, which can be mechanical connection, or direct connection, or connection through intermediate medium, and for those skilled in the art, the basic meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] A stator wire rod end 3D transposition insulation filling forming process, characterized in that it comprises S1, flat copper wire winding: a plurality of flat copper wires are arranged in two rows, and each wire is crossed from one row to the other row twice with the same interval, and the 3D transposition positions on the plurality of flat copper wires are arranged in equal intervals on the two side end faces, thereby forming a wire rod blank 1, refer to Figure 1 、 Figure 2 ; S2, extruding mica mud 2: after mixing the adhesive and the mica powder, the mica mud 2 is extruded; S3, positioning mica mud: the mica mud 2 is glued on both sides of the end surface of the wire rod blank, the release film is stripped, and the gasket containing the glue layer is padded between the flat copper wires; S4, wrapping high-temperature-resistant film: wrapping and fixing the high-temperature-resistant film 3 outside the wire rod blank 1 to form a unified whole; S5, embedding positioning mold 4: referring to Figure 4 , Figure 5 , the wire rod blank 1 is embedded in the positioning mold 4, the end of the wire rod blank 1 protrudes from the end of the positioning mold 4, and the adhesive tape is wrapped around the outside of the positioning mold 4, so that the wire rod blank 1 is clamped and positioned in the positioning mold 4; S6, high-temperature and high-pressure forming: the positioning mold 4 containing the wire rod blank 1 is placed in a hot press tank, 125±5℃ is added to half pressure and heat preservation and pressure for 20-30min, and the temperature is stepped up to 165±5℃ to add full pressure and heat preservation and pressure curing, the temperature and pressure are in a certain range, the temperature is 100-165℃, and the pressure is 0.3-0.6MPa, at this time, the mica mud flows at high temperature, without generating small molecule volatile substances, so that the wire rod blank and the mica mud on the side end form an integral whole, and the recess at the 3D transposition position outside the wire rod blank is filled; S7, discharging and cooling: the wire rod blank 1 is taken out of the hot press tank, the positioning mold 4 is removed, and the high-temperature-resistant film 3 outside the wire rod blank 1 is stripped, and the wire rod blank is naturally cooled, so that the side end transposition winding insulation filling forming is completed.

[0027] In this embodiment, step S2 specifically comprises, a, selecting modified high-temperature-resistant epoxy resin 100-120 parts, aromatic amine-based curing agent 30-50 parts, and latent accelerator 1-3 parts by weight, and mixing to form an adhesive; b, the adhesive and mica powder are sent into a mixer to be pre-mixed into a lump, and the lump is repeatedly extruded to be shaped into a uniform body; c, the mica mud is extruded into an infinite long strip of different widths and thicknesses through a mixing device, and finally the mica mud is attached with a release film and rolled into a disc or made into a long strip.

[0028] In the present application, special mica mud is used, which is pre-mixed into a lump, repeatedly extruded and mixed to make the mixture of epoxy adhesive and mica powder uniform, and finally extruded into a shape. The shaping and use principle of the mica mud utilizes the temperature difference effect. At room temperature, the mica mud can maintain a certain shape as a plastic material, and at high temperature and high pressure, it can be shaped into any shape, thereby filling the recess at the 3D transposition position of the motor coil, and finally curing and shaping into an irreversible solidified material at high temperature, so as to suppress the internal circulation caused by the magnetic induction of the coil and ensure the insulation performance of the motor coil.

[0029] The mica mud in the application has no solvent volatilization, has no small molecule volatiles at high temperature and high pressure, and thus no volatiles are generated in the filling and curing of the coil during the filling and forming, effectively ensuring the insulation of the coil. Since the mica mud has no any reinforcing material for support, the physical properties of the cured product depend entirely on the organic combination of the epoxy resin and the mica mud, the glass transition temperature of the mica mud cured product can reach above 175 DEG C, and the mica mud has good heat resistance and mechanical properties. The internal coil is avoided to be empty during the secondary heat forming of the motor coil in the later period, and the product failure rate caused by the insufficient heat resistance of the filling material is avoided.

[0030] The traditional mica paper and the mica mud in the application are compared in the motor coil transposition and winding insulation filling and forming process as follows:

[0031] On the basis of the embodiment, the adhesive content of the long strip-shaped mica mud prepared in step S2 is 30%-40%, the specific gravity is 1.6-1.9 g / cm 3 , the normal bonding strength is ≥15.3 MPa, the volume resistivity is ≥1.0×10 15 Ω·cm, and the glass transition temperature is ≥175 DEG C.

[0032] On the basis of the embodiment, in step S4, the high-temperature-resistant film 3 is fixed outside the rod blank 1 by being wrapped and fixed by the adhesive tape.

[0033] The positioning mold 4 includes an upper mold 41 and a lower mold 42, the upper mold 41 and the lower mold 42 are spliced to form a rectangular structure, and the upper mold 41 and the lower mold 42 have a rectangular-shaped cavity 43 for embedding the rod blank 1, and the rod blank 1 is arranged between the rectangular-shaped cavities 43 formed by the upper mold 41 and the lower mold 42.

[0034] Further, the upper mold 41 and the lower mold 42 each include an L-shaped body 441, the L-shaped body 441 includes a vertical portion 442 and a horizontal portion 443, one end of the horizontal portion 443 has a stepped portion 444 on the inner side, the vertical portion 442 of the upper mold 41 is matched with the stepped portion 444 of the lower mold 42, and the vertical portion 442 of the lower mold 42 is matched with the stepped portion 444 of the upper mold 41.

[0035] Further, the radial length of the rectangular-shaped cavity 43 formed by the cooperation of the upper mold 41 and the lower mold 42 is consistent with the width of the rod blank 1, and the height of the rectangular-shaped cavity 43 formed by the cooperation of the upper mold 41 and the lower mold 42 is consistent with the height of the rod blank 1. Embodiment 1

[0036] A stator rod end 3D transposition insulation filling and forming process, characterized by comprising S1, winding flat copper wire: a plurality of flat copper wires are arranged in two rows, and each wire is crossed from one row to the other row twice with the same interval, and the 3D transposition on the plurality of flat copper wires is arranged in equal intervals on the two side end faces, so as to form a wire bar blank 1; S2, extruding mica mud 2: a. Selecting modified high-temperature-resistant epoxy resin 100-120 parts, aromatic amine-based curing agent 30-50 parts, and latent accelerator 1-3 parts by weight, and mixing to form an adhesive; b. The adhesive and mica powder are sent into a mixer to be pre-mixed into a lump, and the lump is repeatedly extruded to be shaped into a uniform body; c. The mica mud 2 is extruded into an infinite long strip of different widths and thicknesses through a mixing device, and finally the mica mud 2 is attached with a release film and rolled into a disc or made into a long strip; S3, positioning the mica mud: the mica mud 2 is adhered to the two side end faces of the wire bar blank, the release film is peeled off, and the gasket containing the adhesive layer is placed between the flat copper wires; S4, wrapping high-temperature-resistant film: wrapping and fixing the high-temperature-resistant film 3 outside the wire bar blank 1 to form a unified whole; S5, embedding positioning mold 4: the positioning mold 4 includes an upper mold 41 and a lower mold 42, the upper mold 41 and the lower mold 42 are spliced to form a rectangular structure, and the upper mold 41 and the lower mold 42 have a rectangular cavity 43 for embedding the wire bar blank 1, the wire bar blank 1 is placed between the rectangular cavity 43 formed by the upper mold 41 and the lower mold 42, and the ends of the wire bar blank 1 protrude from the ends of the positioning mold 4, and the adhesive tape is wound around the upper mold 41 and the lower mold 42 to clamp and position the wire bar blank 1 in the positioning mold 4; S6, high-temperature and high-pressure forming: the positioning mold 4 containing the wire bar blank 1 is placed in a hot press tank, 125±5℃ is added to half pressure and kept for 20-30min, and the temperature is stepped up to 165±5℃ to full pressure and kept for solidification, the temperature and pressure are in the range of 100-165℃ and 0.3-0.6MPa, at this time the mica mud flows at high temperature without generating small molecule volatile substances, so that the wire bar blank and the mica mud on the side end form an integrated body, and the recess at the 3D transposition position on the outside of the wire bar blank is filled; S7, unloading and cooling: the wire bar blank 1 is taken out of the hot press tank, the positioning mold 4 is removed, and the high-temperature-resistant film 3 outside the wire bar blank 1 is peeled off, and the wire bar blank is naturally cooled, thereby completing the side end transposition winding insulation filling and forming. Example 2

[0037] Different from example 1, in step S2, modified high-temperature-resistant epoxy resin 120 parts, aromatic amine-based curing agent 50 parts, and latent accelerator 3 parts are selected by weight, and mixed to form an adhesive. Example 3

[0038] Different from example 1, in step S2, modified high-temperature-resistant epoxy resin 110 parts, aromatic amine-based curing agent 40 parts, and latent accelerator 2 parts are selected by weight, mixed to form the adhesive.

[0039] The following table is a data comparison analysis of examples 1 to 3 and traditional mica paper (comparative example) as a filling material in the insulation filling forming process of motor coil transposition winding:

[0040] Among them, the higher the volume resistivity, the better the insulation performance, the higher the glass transition temperature, the better the heat resistance, the mica mud in example 2 is better than the comparative example, example 1 and example 3 in adhesive content, specific gravity, normal cohesive strength, volume resistivity and glass transition temperature, has high insulation performance, avoids the coil inside from being empty during the secondary heat forming of the motor coil in the later period, and causes the product failure rate due to the insufficient heat resistance of the filling material, and is the best implementation mode.

[0041] Those skilled in the art should understand that the present application is not limited to the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A stator bar end 3D transposition insulation filled molding process characterized by: Comprising S1, winding flat copper wire: arrange the multiple flat copper wires into two columns, and each wire is crossed from one column to another twice with the same interval, and the 3D transposition on the multiple flat copper wires is arranged at equal intervals on the two side end faces, thereby forming a wire rod blank (1); S2, extruding mica mud (2): mixing the adhesive and mica powder and then extruding the mica mud (2); S3, positioning the mica mud: gluing the mica mud (2) on the two side end faces of the wire rod blank, peeling off the release film, and placing the gasket containing the adhesive layer between the flat copper wires; S4, wrapping the high-temperature-resistant film: wrapping and fixing the high-temperature-resistant film (3) on the outside of the wire rod blank (1) to form a unified whole; S5, embedding and positioning the mold (4): embedding the wire rod blank (1) in the positioning mold (4), and the ends of the wire rod blank (1) protrude from the ends of the positioning mold (4), and the adhesive tape is wrapped around the outside of the positioning mold (4) to clamp and position the wire rod blank (1) in the positioning mold (4); S6, high-temperature and high-pressure forming: placing the positioning mold (4) containing the wire rod blank (1) in the hot press tank, adding half pressure at 125±5℃ for 20-30min, and then increasing the temperature in stages to 165±5℃ to add full pressure and pressure solidification, the temperature and pressure are in the range of 100-165℃ and 0.3-0.6MPa, at this time the mica mud flows at high temperature, without generating small molecule volatile substances, so that the wire rod blank and the mica mud on the side end form an integral whole, and the recess at the 3D transposition on the outside of the wire rod blank is filled; S7, discharging and cooling: taking out the wire rod blank (1) from the hot press tank, removing the positioning mold (4), and peeling off the high-temperature-resistant film (3) on the outside of the wire rod blank (1), and then naturally cooling the wire rod blank, thereby completing the side end transposition winding insulation filling and forming.

2. The stator bar end 3D transposition insulation filled molding process of claim 1, wherein: The step S2 comprises, a, selecting modified high-temperature-resistant epoxy resin 100-120 parts, aromatic amine-based curing agent 30-50 parts, and latent accelerator 1-3 parts by weight, and mixing to form an adhesive; b, feeding the adhesive and mica powder into a mixer to pre-mix into a lump, and repeatedly extruding the lump to form a uniform body; c, extruding the mica mud (2) into an infinite long strip type with different widths and thicknesses through a mixing device, and finally attaching a release film to the mica mud (2) to roll it into a disc shape or make it into a long strip shape.

3. The stator bar end 3D transposition insulation filled molding process of claim 2, wherein: The adhesive content of the long strip mica paste prepared in the step S2 is 30%-40%, the specific gravity is 1.6-1.9 g / cm 3 , the normal bonding strength is ≥15.3 MPa, the volume resistivity is ≥1.0×10 15 Ω·cm, and the glass transition temperature is ≥175℃.

4. The stator bar end 3D transposition insulation filled molding process of claim 3, wherein: In the step S4, the high-temperature-resistant film (3) is wrapped and fixed on the outside of the wire rod blank (1) by the adhesive tape.

5. A process for 3D transposition and potting of end turns of stator bars as claimed in claim 4 wherein: The positioning mold (4) comprises an upper mold (41) and a lower mold (42), the upper mold (41) and the lower mold (42) are spliced to form a rectangular structure, and the upper mold (41) and the lower mold (42) have a rectangular cavity (43) for embedding the wire rod blank (1), and the wire rod blank (1) is arranged between the rectangular cavities (43) formed by the upper mold (41) and the lower mold (42).

6. A process for 3D transposition and potting of end turns of stator bars as claimed in claim 5 wherein: The upper die (41) and the lower die (42) each comprise an L-shaped body (441) comprising a vertical portion (442) and a horizontal portion (443), one end of the horizontal portion (443) having a stepped portion (444) inside, the vertical portion (442) of the upper die (41) being matched with the stepped portion (444) of the lower die (42), and the vertical portion (442) of the lower die (42) being matched with the stepped portion (444) of the upper die (41).

7. A process for 3D transposition and potting of end turns of stator bars as claimed in claim 6 wherein: The rectangular cavity (43) formed by matching the upper die (41) and the lower die (42) has a radial length consistent with the width of the wire rod blank (1), and a height consistent with the height of the wire rod blank (1).

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