A method for soldering aluminum enameled wire in a shaded-pole motor

Abstract

This application discloses a method for soldering aluminum enameled wire in a shaded-pole motor. The method involves simultaneously winding both the un-removed and removed portions of the aluminum enameled wire's terminals onto the lead wire core to form a connection structure. This increases the stress-bearing area of ​​the aluminum enameled wire during the connection process, helping to distribute the pressure on the removed portions and increasing the tensile strength of the wire. By using lead-free solder bars and aluminum flux as raw materials in a soldering furnace to solder the connection structure, tinning becomes easier, resulting in a more uniform, full, and immersion-free solder joint, improving tinning effect and efficiency. The use of a heat-sealed double-walled tube to seal the solder joint prevents oxidation and brittle fracture caused by prolonged exposure to air. Multiple cleaning steps remove residual paint remover from the removal process and residual flux from the soldering process, preventing these residues from oxidizing the solder joint and causing brittle fracture.

Description

Technical Field

[0001] This invention belongs to the field of welding technology, and in particular relates to a method for soldering aluminum enameled wires in a shaded-pole motor. Background Technology

[0002] Enameled wire is an important component of the winding of a shaded-pole motor. Specifically, enameled wire consists of an inner conductor and an outer insulation layer (polyester enamel). The bare wire is annealed and softened, then coated with enamel multiple times and baked to form a conductor with four major properties: mechanical, chemical, electrical, and thermal properties.

[0003] Specifically, there are different types of enameled wire, including copper enameled wire, aluminum enameled wire, copper-clad aluminum enameled wire, etc. However, with the changing environment and the soaring copper price this year, many motor manufacturers have found it difficult to control material costs, pushing their capacity to the limit. Through life tests, salt spray tests, and thermal shock tests, it has been concluded that aluminum enameled wire is no worse than copper enameled wire in terms of temperature rise, current, and energy efficiency. From a design perspective, aluminum enameled wire can completely replace copper enameled wire. However, due to the extremely reactive nature of aluminum, the weld joint is prone to oxidation and brittle fracture after welding aluminum enameled wire to the lead wire. It is also difficult to tin during welding, and the tensile strength of the weld joint is not as good as that of copper wire. These factors limit the application of aluminum enameled wire in motors. Furthermore, if the soldering method for aluminum enameled wire is not perfect, the product is prone to burning out after being powered on, resulting in a short product lifespan. Aluminum enameled wire also poses a series of fatal defects when used in electrical appliances or household appliances. Summary of the Invention

[0004] (a) Purpose of the invention

[0005] To overcome the above shortcomings, the present invention aims to provide a method for soldering aluminum enameled wires for shaded-pole motors, thereby solving the technical problems of poor tensile strength at the soldering position, difficulty in tinning, and easy oxidation and brittle fracture after soldering aluminum enameled wires and lead wires.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the technical solution provided in this application is as follows:

[0008] A method for soldering aluminum enameled wire in a shaded-pole motor includes:

[0009] Paint stripping: The terminals of the aluminum enameled wire wound into a coil shape are placed into a paint stripping furnace containing paint stripping agent for paint stripping.

[0010] First cleaning: Clean the terminals of the aluminum enameled wire after the paint has been removed with clean water;

[0011] Wiring: The unvarnished and varnished parts of the aluminum enameled wire after one cleaning are simultaneously wound around the lead wire core to form a wiring structure;

[0012] Soldering: The lead-free solder bar and aluminum flux are placed into the soldering furnace, and the wiring structure is placed into the soldering furnace to form a solder joint;

[0013] Secondary cleaning: Clean the aluminum solder flux off the welding head;

[0014] Sealing: The heat-sealed double-walled tube is inserted into the weld head after secondary cleaning to isolate the weld head from the air;

[0015] By simultaneously winding both the un-removed and removed portions of the aluminum enameled wire's terminals onto the lead wire core to form a connection structure, the stress-bearing area of ​​the aluminum enameled wire is increased during the connection process. This helps to disperse the pressure on the removable portion of the aluminum enameled wire, resulting in higher tensile strength. By using lead-free solder bars and aluminum soldering flux as raw materials in a soldering furnace to solder the connection structure, it is easier to apply solder, resulting in a more uniform, full, and immersion-free solder joint, improving the soldering effect and efficiency. By using a heat-sealed double-walled tube to seal the solder joint, the solder joint can be prevented from oxidizing and breaking easily due to long-term exposure to air. Multiple cleaning steps can remove residual paint remover from the removal process and residual flux from the soldering process, preventing these residues from oxidizing the solder joint and causing it to break.

[0016] In some embodiments, wiring includes: wrapping the un-removed portion of the aluminum enameled wire terminal more than 2 turns around the lead wire core and wrapping the unremoved portion of the aluminum enameled wire terminal more than 3 turns around the lead wire core.

[0017] In some embodiments, soldering includes: suspending a solder depth limiting block on one side of the soldering furnace liner and placing the wiring structure onto the limiting block for soldering, wherein...

[0018] The soldering depth limiting block includes: two hanging ears on opposite sides of the inner edge of the soldering furnace and a solder dipping plate between the two hanging ears. The width of the solder dipping plate is half the width of the inner edge of the soldering furnace and the solder dipping plate is recessed to a predetermined depth in the direction of the inner edge of the furnace.

[0019] By setting a solder depth limit block to tin the wiring structure, the predetermined depth to which the wiring structure extends into the soldering furnace can be limited. This can prevent the wire insulation from melting due to excessive depth and the solder layer from wrapping around the wire insulation, which could easily cause the solder layer to break.

[0020] In some embodiments, before the heat-sealed double-walled tube is fitted onto the welding head, the method further includes: removing burrs and sharpening structures from the welding head;

[0021] Removing burrs and sharpened structures from the welding head can prevent them from piercing the heat-sealed double-walled tube when it is fitted, thus preventing oxidation and brittle fracture of the welding head.

[0022] In some embodiments, prior to paint stripping, the method further includes: attaching the coil to the side opposite to the paint stripping oven with adhesive tape;

[0023] By attaching adhesive tape to the opposite side, that side can be shielded to prevent paint stripper from splashing out and damaging the coil, which could lead to poor inter-turn quality or motor burnout and other safety hazards.

[0024] In some embodiments, soldering includes: controlling the soldering furnace temperature between 340-365°C and controlling the soldering time to within two seconds;

[0025] By controlling the temperature of the soldering furnace, the solder joints can be made more uniform, full, and free of tin dipping without burning the aluminum enameled wire, thus improving the tinning effect and efficiency. Attached Figure Description

[0026] Figure 1 This is a flowchart of the aluminum enameled wire soldering method for shaded-pole motors according to the present invention;

[0027] Figure 2 This is a diagram showing the state of the aluminum enameled wire after the paint has been removed according to the present invention;

[0028] Figure 3 This is a cross-sectional view of the aluminum enameled wire and lead wire of the present invention after connection;

[0029] Figure 4 This is an assembly diagram of the solder depth limiting block of the present invention installed on a soldering furnace;

[0030] Figure 5 This is a side view of the solder depth limiting block of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0032] This invention provides a method for soldering aluminum enameled wire 4 of a shaded-pole motor, comprising:

[0033] Paint stripping: The terminals of the aluminum enameled wire 4, which is wound into a coil shape, are placed into a paint stripping furnace containing paint stripping agent for paint stripping.

[0034] First cleaning: Since the paint remover has a strong oxidizing property, after the paint is removed, the terminals of the aluminum enameled wire 4 need to be cleaned with water and the water stains on the terminals of the enameled wire need to be wiped clean.

[0035] Wiring: The un-removed enamel portion 402 and the removed enamel portion 401 of the cleaned aluminum enameled wire 4 are simultaneously wound around the lead wire 3 core 301 a predetermined number of times to form a wiring structure.

[0036] Soldering: The lead-free solder bar and aluminum flux are placed into soldering furnace 1 and the wiring structure is placed into soldering furnace 1 to form a solder joint;

[0037] Secondary cleaning: Due to the high oxidizing properties of aluminum solder flux, the aluminum solder flux on the soldering head is cleaned after tinning.

[0038] Sealing: The heat-sealed double-walled tube 6 is fitted onto the welding head and both ends of the heat-sealed double-walled tube 6 are sealed to isolate the welding head from the outside air.

[0039] Specifically, this application will use a fully automatic winding machine to wind the aluminum enameled wire 4 into a coil shape. When winding, it is necessary to adjust the winding tension and the winding speed. If the winding tension is too large or the winding speed is too high, the aluminum enameled wire 4 may be easily broken.

[0040] Specifically, during the stripping process, pour the stripping agent for the aluminum enameled wire into the stripping furnace. Then, insert the heating coupler of the temperature controller into the furnace and set the heating temperature to one of the values ​​between 330-390℃. Next, place the wire terminals into the furnace for stripping. Before stripping, wrap the side of the coil facing the furnace with adhesive tape to prevent the stripping liquid from splashing out and damaging the coil, which could lead to poor coil winding or even motor burnout and other safety hazards. During the stripping process, bubbles will continuously emerge from the furnace. When no more bubbles appear, it indicates that the enamel film on the terminals has been removed. After stripping, to prevent oxidation caused by residual stripping liquid, the terminals should be rinsed in clean water and then wiped dry with a cloth.

[0041] Preferably, during the wiring process, the un-removed enamel portion 402 of the enameled wire is wound more than 2 turns around the core 301 of the lead wire 3, and the enamel-removed portion 401 is wound more than 3 turns around the core 301. The distance between the winding coils is controlled at 1-2mm, and 5-8mm of excess wire is reserved at the end. Compared with the existing method where only the enamel-removed portion 401 is directly soldered to the lead wire 3, this application can increase the stress area of ​​the enameled wire, help disperse the pressure borne by the enamel-removed portion 401, and improve the tensile strength of the enameled wire.

[0042] Specifically, during soldering, the wiring structure is placed in the soldering furnace 1 for soldering. Because it is difficult to tin the aluminum enameled wire 4, this application uses lead-free solder bars and aluminum solder flux as raw materials to be heated and melted in the soldering furnace 1. Note that the temperature of the soldering furnace should not be too high to avoid directly melting the aluminum enameled wire 4. This application adjusts the temperature of the soldering furnace 1 to 340-365℃ and controls the soldering time to within 2 seconds. This ensures that the solder head is full and there is no poor tinning without melting the aluminum enameled wire 4, which can greatly improve the soldering efficiency.

[0043] In order to avoid the wire insulation of the lead wire 3 being burned due to the wire structure extending too deep into the soldering furnace 1 during the soldering process, and to avoid the solder layer 5 being easily stretched open when it wraps around the wire insulation of the lead wire 3, preferably, this application uses a solder depth limiting block 2 for soldering.

[0044] Specifically, the solder depth limiting block 2 includes: two hanging ears 201 hanging on opposite sides of the inner liner 101 of the soldering furnace 1 and a tin-dipping plate 202 disposed between the two hanging ears 201. Specifically, the width of the tin-dipping plate 202 is half the width of the inner liner 101 of the soldering furnace 1 and the tin-dipping plate 202 is recessed to a predetermined depth (4-5mm) in the depth direction of the inner liner 101. Specifically, during tinning, the motor's lead wire 3 is first stripped (the stripped length is 8-10mm). At this time, the soldering furnace 1 heats its inner chamber 101 (the processing temperature of the soldering furnace 1 is 340 to 365 degrees Celsius). The heated solder in the inner chamber 101 is then poured onto the tin-dipping plate 202 on the solder depth limiting block 2. Since the width of the tin-dipping plate 202 is half the width of the inner chamber 1013 of the soldering furnace 1, if the solder is insufficient, solder bars can be added to the inner chamber 101 of the soldering furnace 1 to allow the solder to re-immerse itself onto the tin-dipping plate 202. Specifically, in... During processing, the user immerses the stripped wire structure in the tin-dipping plate 202. At this time, because the tin-dipping plate 202 is recessed into the inner liner 101 to a depth of 4 to 5 mm, the height of the molten solder on the tin-dipping plate 202 is also 4 to 5 mm. During immersion, the molten solder will not damage the aluminum enameled wire 4 and the lead wire 3. The height of the solder layer 5 only covers the position of the wire core 301. Specifically, the tin-dipping plate 202 and the hanging ear 201 are made of titanium alloy, which can work at the high temperature of the soldering furnace 1 for a long time during use. Compared with the existing technology, it can limit the immersion depth of the wire structure.

[0045] Specifically, for secondary cleaning, the solder head is immersed in an alcohol container and brushed until it is shiny and free of flux residue. Because aluminum solder flux is highly corrosive (containing acids and alkalis), ordinary liquids cannot clean it effectively; therefore, industrial alcohol with a concentration of 95% or higher must be used. Furthermore, since aluminum is a chemically reactive metal, it quickly forms an oxide film upon contact with air. Wiping its surface with alcohol can remove flux and grease, allowing the exposed aluminum material of the aluminum enameled wire 4 to form a more complete oxide film. After cleaning the solder head area of ​​the aluminum wire sheath, the aluminum enameled wire 4 needs to be placed in the heating and cooling / weathering zones of a drying oven to remove the adsorbed alcohol (drying oven design temperature: 75-85℃).

[0046] Preferably, during the secondary cleaning process, all burrs and sharp points on the welding head can be cut off at the same time to prevent the welding head from being exposed to the air and oxidizing and breaking when the heat-sealed double-walled tube 6 is subsequently inserted.

[0047] Specifically, the heat-sealed double-wall tube 6 can also simultaneously cover the sheath of the lead wire 3 near the wire core 301.

[0048] Specifically, the hot-air double-walled tube contains a layer of hot-melt adhesive. After heating, the hot-melt adhesive liquefies, blocking the front and rear air outlets of the double-walled tube. Sealing both ends of the double-walled tube isolates the welding head from the outside air. After the heat-sealed double-walled tube 6 is fitted onto the welding head, the aluminum enameled wire 4 is placed onto the conveyor belt of the tunnel furnace. The conveyor belt transports the aluminum enameled wire 4 into the tunnel furnace and out from the other end. The tunnel furnace temperature is set to 115±5℃, and the speed of the conveyor belt is set to ≤20r / min. As the heat-sealed double-walled tube 6 moves within the tunnel furnace, the liquefied hot-melt adhesive blocks the front and rear air outlets of the double-walled tube, preventing the welding head of the aluminum enameled wire 4 from being exposed to air and avoiding oxidation. Furthermore, the liquefied hot-melt adhesive hardens and adheres to the aluminum enameled wire 4, increasing the mechanical strength of the wire.

[0049] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A method of soldering shielded pole motor aluminum enameled wire, characterized by, The method comprises: Paint removal: putting the terminal of the aluminum enameled wire wound into a coil shape into a paint removal furnace containing a paint removal agent for paint removal; Primary cleaning: cleaning the terminal of the aluminum enameled wire after paint removal with clean water; Wiring: winding the un-painted part and the painted part of the terminal of the aluminum enameled wire after primary cleaning on the core of the lead-out wire to form a wiring structure; Soldering: putting a lead-free solder strip and an aluminum flux into a soldering furnace and putting the wiring structure into the soldering furnace for soldering to form a solder joint; Secondary cleaning: cleaning the aluminum flux on the solder joint; Sealing: putting a heat-sealed double-wall tube on the solder joint after secondary cleaning to air-seal the solder joint; wherein the heat-sealed double-wall tube has a layer of hot melt glue inside, which is liquefied after heating, and the front and rear air outlets of the double-wall tube are blocked, and the sealing of the two ends of the double-wall tube can isolate the solder joint from the external air.

2. The method of claim 1, wherein, The wiring comprises: winding the un-painted part of the terminal of the aluminum enameled wire more than 2 turns on the core of the lead-out wire and winding the painted part of the terminal of the aluminum enameled wire more than 3 turns on the core of the lead-out wire.

3. The method of claim 1, wherein, The soldering comprises: suspending a soldering depth limiting block on one side of the inner container of the soldering furnace and placing the wiring structure on the limiting block for soldering, wherein The soldering depth limiting block comprises: two hanging ears hung on the edges of the opposite sides of the inner container of the soldering furnace and a soldering plate arranged between the two hanging ears, the width of the soldering plate is half of the width of the inner container of the soldering furnace, and the soldering plate is recessed in the depth direction of the inner container by a predetermined depth.

4. The method of claim 1, wherein, Before the heat-sealed double-wall tube is put on the solder joint, it further comprises: removing burrs and sharpening structure on the solder joint.

5. The method of claim 1, wherein, Before paint removal, it further comprises: attaching masking tape to the side opposite to the coil from the paint removal furnace.

6. The method of claim 1, wherein, The soldering comprises: controlling the temperature of the soldering furnace between 340-365℃ and controlling the soldering time within 2S.

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