Slot bottom copper wire stator injection molding method

Abstract

The invention discloses a slot bottom copper wire injection molding stator method, which belongs to the technical field of stator processing technology methods, and comprises the following steps: (A) iron core processing: forming a stator iron core through stamping, bulk sheet stacking and welding, (B) insulating layer injection molding: carrying out injection molding on a stator slot of the stator iron core by using a thermosetting material to form an insulating layer, (C) coil forming: performing wire forming on a copper wire, and inserting the copper wire into the stator core after wire forming, (D) coil potting: performing potting on a potting adhesive according to each groove from a wire inlet end by using a potting mold, enabling the potting adhesive to flow into the wire grooves to fill gaps, heating the iron core to cure the potting adhesive, removing a potting tool, and performing coil potting. (E) coil end processing: shearing and welding the end part of the motor, and (F) coating: coating after preheating the stator, and heating and curing the stator, the stator coil can be fastened in the stator slot through injection molding of the insulating layer and coil potting, and the quality of the motor is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of motor processing technology methods, and relates to a stator processing technology method, in particular to a slot bottom copper wire injection molding stator method. Background Art

[0002] The motor is a commonly used mechanical device used in various industries. The production process of the motor is usually to stamp silicon steel sheets and then stack them to form a stator. After setting insulating paper in the stator slots, the wire is wound in the stator slots to form a coil. Since the position of the coil in the stator slot is not fixed, there is a gap between the coil and the stator core. During long-term use, the coil will shake in the stator slot, thereby affecting the quality of the motor.

[0003] In the existing technology, some use potting methods to fix the position of motor coils and improve the insulation performance of the motor. The invention patent with publication number CN115714491A discloses a motor stator end potting structure and method, providing a potting cover for the potting boundary, a fixed slot wedge for fixing the potting cover, and a fastening rope for tightening the fixed slot wedge. It also discloses a potting method, which is applied to the wire embedding slots and ends of the motor stator core. While providing a potting cavity for the motor stator end and ensuring the insulation and protection performance of the motor stator end, it simplifies the potting structure, reduces process cost and process time, and improves potting quality. It is suitable for end potting of various types of motors.

[0004] The production process uses a potting structure method, but since insulating paper is still used to insulate the stator coil and the stator core, the filling effect is affected during the filling process. In addition, the filling is mainly carried out on the stator end, and the stability of the coil cannot be met, affecting the quality of the product. Summary of the Invention

[0005] The purpose of the present invention is to overcome the technical problems in the prior art that due to the gap between the coil and the stator core slot, the coil will shake in the stator slot during long-term use, affecting the insulation and quality of the motor.

[0006] In order to solve the above technical problems, the present invention provides a method for injecting copper wire into a stator at the bottom of a slot, comprising the following steps: Step (A) Iron core processing: forming stator iron core fragments with slots by stamping, stacking the fragments to a corresponding height and then welding them to form a stator iron core with stator slots.

[0007] The loose sheets are punched out using a punching machine and stacked according to the required height. The core height is measured under a pressure of 2-4T. The number of sheets is increased or decreased according to the height requirement. The core is shaped under a pressure of 20T-30T and laser welded. After welding, the tooth profile of the stator slot is measured to check whether the size meets the drawing requirements.

[0008] Step (B) Insulation Layer Injection: The stator slots of the stator core are injection molded with a thermosetting material. A mold core is placed in the stator slots, the thermosetting material is heated, and then injected into the stator slots. A cooling device is provided on the mold core. After the injection is completed, the mold core is cooled, and the thermosetting material is cooled and then demolded to form an insulation layer.

[0009] Step (C) Coil Forming: First, the copper wire is formed into a wire. After the wire is formed, the copper wire is inserted into the stator slot of the stator core. After the insertion, the copper wire is pressed into the stator core to form a coil.

[0010] Step (D) potting: After installing the potting mold on the stator core, the stator core and coil are heated in a drying oven. The potting glue is poured into the slots from the wire inlet end of the stator core, so that the potting glue flows into the stator slots to fill the gaps in the slots. The stator core is heated to solidify the potting glue, and the potting tooling is removed.

[0011] Step (E) Coil end processing: The stator core end is first sheared and welded, and the lead wire is sheared, expanded and welded.

[0012] Step (F) coating: preheat the stator core, and then coat it. Coat it 1-4 times, heat and cure the stator core, and ensure that there is no local exposure, delamination, cracking, or filamentous adhesion in the coating area.

[0013] In this process, an insulating layer is first injected with thermosetting material in the stator core slots to replace the original insulating paper. The stator core slots are then potted and the potting glue is poured into each slot. After potting, the coils are cured to completely fix them in the stator slots, avoiding coil shaking due to gaps in the slots, which affects the quality of the motor.

[0014] As a further improvement to the present invention, the distance between the mold core and the stator slot edge in step (B) is 0.1-0.3 mm, and the thickness of the thermosetting material in the stator slot is 0.1-0.3 mm. To ensure sufficient space for wire installation, a gap of 0.1-0.3 mm is left between the mold core and the stator edge during the insulation layer injection molding process, ensuring that the insulation layer thickness is between 0.1-0.3 mm.

[0015] As a further improvement measure of the present invention, the temperature during the heating process in step (B) of the above-mentioned method for injecting copper wire into a stator with a slot bottom is 130° C.-200° C.

[0016] As a further improvement measure of the present invention, the wire forming step in step (C) of the above-mentioned slot bottom copper wire injection molding method includes laser removal of paint, twisting the copper wire, and extrusion molding of the copper wire. During the extrusion molding process, the parallel gap between the copper wires before twisting is less than 0.45 mm. After twisting, the parallel gap between the copper wires is less than 3.5 mm, and the back-to-back gap between the copper wires is less than 1 mm. The paint of the molded wire has no defects such as damage, wrinkles, cracks, and bubbles. The enameled wire is stripped cleanly without paint residue, and the shape of the molded wire conforms to the simulated shape.

[0017] As a further improvement measure of the present invention, in step (D) of the above-mentioned method for injecting copper wire into a stator with a slot bottom, the drying tunnel heating temperature is 60°C-100°C, the curing heating temperature is 110°C-140°C, and the curing heating time is 1.5-3 hours. The preheating temperature and curing temperature are limited to ensure the curing effect of the sealing and potting glue.

[0018] As a further improvement measure of the present invention, the sealing glue used in step (D) of the above-mentioned method for injecting copper wires into a stator at the bottom of a slot is anhydride glue.

[0019] As a further improvement of the present invention, in step (D) of the above-mentioned method for injecting copper wire into a stator with a slot bottom, vacuum potting is performed with a vacuum degree of 1-8 Bar. The vacuum potting ensures that the potting compound completely covers the stator core slots.

[0020] As a further improvement measure of the present invention, in step (F) of the above-mentioned method for injecting copper wire into a stator with a bottom slot, the stator preheating in the coating process needs to be heated up five times, with the initial temperature being 75°C-95°C and the preheating time being 60s-80s. After the first heating, the temperature is 95°C-115°C and the preheating time is 55s-75s. After the second heating, the temperature is 110°C-130°C and the preheating time is 55s-75s. After the third heating, the temperature is 120°C-140°C and the preheating time is 55s-75s. After the fourth heating, the temperature is 140°C-160°C and the preheating time is 60s-80s. After the fifth heating, the temperature is 210°C-230°C and the preheating time is 40s-60s.

[0021] As a further improvement of the present invention, in step (F) of the above-mentioned method for injection molding a stator with slot bottom copper wire, the coating method is powder coating, the powder coating time is 0.1s-3s, the rotation speed is 170-270deg / min, and the powder coating interval is 0.5-3s.

[0022] As a further improvement of the present invention, in the above-mentioned method for injecting copper wire into a stator with a slot bottom, the wire temperature in step (F) during coating is 135°C-155°C, and the temperature during heating and curing of the stator is 150°C-170°C.

[0023] After coating, the stator core is NTC assembled, and then subjected to appearance inspection and electrical performance inspection.

[0024] Compared with the prior art, the beneficial effects of the present invention are: 1. The coil in the stator core slot is fixed through processes such as iron core stamping, insulation layer injection molding, coil forming, potting, coil end processing and coating. The good connection between the injection-molded insulation layer and the sealing and potting glue is utilized to ensure the insulation layer effect while positioning the coil position, preventing the coil from shifting and shaking in the stator slot during long-term use, thereby improving product quality; 2. Potting is performed under negative pressure so that the sealing and potting glue flows evenly into the stator slot, ensuring the fixed state of the stator core, ensuring product quality, and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a process flow chart of the present invention DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] like Figure 1 A method for injecting copper wire into a stator at the bottom of a slot is shown, comprising the following steps: Step (A) Iron core processing: forming stator iron core fragments with slots by stamping, stacking the fragments to a corresponding height and then welding them to form a stator iron core with stator slots.

[0028] The loose sheets are punched out using a punching machine and stacked according to the required height. The core height is measured under a pressure of 3T, and the number of sheets is increased or decreased according to the height requirement. The core is shaped under a pressure of 25T and laser welded. After welding, the tooth profile of the stator slot is measured to check whether the size meets the drawing requirements.

[0029] Step (B) Insulation Layer Injection: The stator slots of the stator core are injection molded with thermosetting material. A mold core is placed in the stator slot, with a distance of 0.2 mm between the mold core and the edge. The thickness of the thermosetting material in the slot is 0.2 mm. To ensure space for wire installation, a 0.2 mm gap is left between the mold core and the edge of the stator slot during the insulation layer injection process. This ensures that the insulation layer is within 0.2 mm thickness. The thermosetting material is heated to 155°C and injected into the stator slot. A cooling device is installed on the mold core. After injection, the mold core is cooled to allow the thermosetting material to cool before demolding to form the insulation layer. After the insulation layer is formed, the slot shape is inspected to ensure that it meets the drawing requirements.

[0030] Step (C) Coil Forming: The copper wire is formed. This involves laser coating removal, twisting, and extrusion. During the extrusion process, the parallel gap between the copper wires is less than 0.45 mm before twisting and less than 3.5 mm after twisting. The back-to-back gap between the copper wires is less than 1 mm. The finished wire must be free of defects such as damage, wrinkles, cracks, or blistering. The enameled wire must be stripped cleanly with no residual coating, and the finished wire shape must conform to the desired shape. After forming, the copper wire is inserted into the stator core slots. After insertion, the copper wire is pressed into the stator core, ensuring that there are no missing insertions and the wire shape is neat.

[0031] Step (D) Potting: After installing the potting mold on the stator core, the wire package is heated in a drying oven at 75°C to allow the potting glue to flow into the wire slots and fill the gaps. The potting glue is an anhydride glue. The core is heated to cure the potting glue at a curing temperature of 130°C for 2 hours. The preheating temperature and curing temperature are limited to ensure the curing effect of the potting glue. The potting glue is potted into the slots from the wire inlet end of the stator core. Vacuum potting is used during the potting process with a vacuum degree of 3 Bar to ensure that the potting glue can completely cover the stator core slots. The potting tooling is removed.

[0032] Step (E) Coil end processing: first cut and weld the motor end, and cut, expand and weld the lead wire.

[0033] Step (F) coating: preheating the stator, coating after preheating, and heating and curing the stator. The stator preheating in the coating process requires 5 temperature increases, the initial temperature is 85°C and the preheating time is 70s, the temperature after the first temperature increase is 105°C and the preheating time is 65s, the temperature after the second temperature increase is 120°C and the preheating time is 65s, the temperature after the third temperature increase is 130°C and the preheating time is 65s, the temperature after the fourth temperature increase is 150°C and the preheating time is 70s, the temperature after the fifth temperature increase is 220°C and the preheating time is 50s, and coating is performed twice. Powder dipping is required during the coating process. The first powder dipping time is 0.2s, the rotation speed is 200deg / min, the powder dipping interval is 2s, the powder dipping time during the second coating process is 0.5s, the rotation speed is 200deg / min, the line temperature during the coating process is 145°C, and the temperature during the stator heating and curing process is 160°C.

[0034] After coating, the stator core is NTC assembled, and then subjected to appearance inspection and electrical performance inspection.

[0035] The coils in the stator core slots are fixed through processes such as core stamping, insulation layer injection molding, coil forming, potting, coil end processing and coating. The good connection between the injection-molded insulation layer and the sealing and potting glue is utilized to ensure the insulation effect while positioning the coils, preventing the coils from shifting and shaking in the stator slots during long-term use, thereby improving product quality.

[0036] The above describes the embodiments of the present invention in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. A person skilled in the art may make several modifications and improvements without departing from the present invention, and these should also be considered to fall within the scope of protection of the present invention.

Claims

1. A method for injection molding a stator with slot bottom copper wire, characterized in that: The method for injecting copper wire into a stator at the bottom of a slot comprises the following steps: Step (A) iron core processing: forming stator iron core fragments with slots by stamping, stacking the fragments to a corresponding height and then welding them to form a stator iron core with stator slots; Step (B) Insulation Layer Injection: A thermosetting material is injection molded into the stator slots of the stator core. A mold core is placed in the stator slots, the thermosetting material is heated, and then injected into the stator slots. A cooling device is provided on the mold core. After the injection is completed, the mold core is cooled, and the thermosetting material is cooled and then demolded to form an insulation layer. Step (C) coil forming: forming the copper wire, inserting the copper wire into the stator slot of the stator core after the wire forming, and pressing the copper wire into the stator core after the insertion to form a coil; Step (D) potting: After installing the potting mold on the stator core, the stator core and coil are heated in a drying oven. The potting glue is poured into the slots from the wire inlet end of the stator core, so that the potting glue flows into the stator slots and fills the gaps in the slots. The stator core is heated to solidify the potting glue, and the potting tooling is removed; Step (E) Coil end processing: first shear and weld the stator core end, and shear, expand and weld the lead wire; Step (F) coating: preheating the stator core, coating after preheating, coating 1-4 times, and heating and curing the stator core.

2. The method for injecting copper wire into a stator at the bottom of a slot according to claim 1, characterized in that: In step (B), the distance between the mold core and the edge of the stator slot is 0.1-0.3 mm, and the thickness of the thermosetting material in the stator slot is 0.1-0.3 mm.

3. The method for injecting copper wire into a stator at the bottom of a slot according to claim 2, characterized in that: The temperature during the heating process in step (B) is 130°C-200°C.

4. The method for injecting copper wire into a stator at the bottom of a slot according to claim 1, characterized in that: In step (C), the wire forming step includes laser removal of the paint film, twisting the copper wire, and extrusion forming the copper wire. During the extrusion forming process, the parallel gap between the copper wires is less than 0.45 mm before twisting, and after twisting, the parallel gap between the copper wires is less than 3.5 mm, and the back-to-back gap between the copper wires is less than 1 mm.

5. The method for injecting copper wire into a stator at the bottom of a slot according to claim 4, characterized in that: In step (D), the drying tunnel heating temperature is 60° C.-100° C., the curing heating temperature is 110° C.-140° C., and the curing heating time is 1.5-3 hours.

6. The method for injecting copper wire into a stator at the bottom of a slot according to claim 1, characterized in that: The sealing glue used in step (D) is an anhydride glue.

7. The method for injecting copper wire into a stator at the bottom of a slot according to claim 6, characterized in that: In step (D), vacuum potting is used during the potting process, and the vacuum degree is 1 Bar to 8 Bar.

8. The method for injecting copper wire into a stator at the bottom of a slot according to claim 7, characterized in that: In the coating process in step (F), the stator core is preheated for 5 temperature increases, with an initial temperature of 75°C-95°C and a preheating time of 60s-80s. After the first temperature increase, the temperature is 95°C-115°C and the preheating time is 55s-75s. After the second temperature increase, the temperature is 110°C-130°C and the preheating time is 55s-75s. After the third temperature increase, the temperature is 120°C-140°C and the preheating time is 55s-75s. After the fourth temperature increase, the temperature is 140°C-160°C and the preheating time is 60s-80s. After the fifth temperature increase, the temperature is 210°C-230°C and the preheating time is 40s-60s.

9. The method for injecting copper wire into a stator at the bottom of a slot according to claim 8, characterized in that: The coating method of step (F) is powder dipping coating, the powder dipping time is 0.1s-3s, the rotation speed is 170-270deg / min, and the powder dipping interval is 0.5-3s.

10. The method for injecting copper wire into a stator at the bottom of a slot according to claim 9, characterized in that: The line temperature during the coating process of step (F) is 135°C-155°C, and the temperature during the heating and curing process of the stator core is 150°C-170°C.

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