Brazing welding device and brazing welding method

Abstract

The invention discloses a brazing welding device and a brazing welding method, and the brazing welding device comprises a welding seat, a pressing piece and an induction heater. A copper terminal is placed on the welding seat; the pressing piece comprises a first pressing part used for pressing the copper terminal on the welding seat and a second pressing part used for pressing the aluminum wire on the copper terminal; the induction heater utilizes induction current to heat, only the brazing filler metal is melted in the brazing process, and the brazing filler metal is fully diffused with the aluminum wire and the copper terminal to form firm metallurgical bonding. According to the brazing welding device, induction welding is used for replacing a traditional flame welding mode, no open fire exists in the whole welding process, the risk of fire disasters is reduced, and meanwhile the vision or skin of operators cannot be injured; meanwhile, only brazing filler metal is melted in the induction welding process, the first welding piece and the second welding piece are both kept in a solid state, and the welding difficulty is reduced; the induction welding has the advantages of high heating speed, high efficiency and the like, the welding time can be shortened, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This application relates to the technical field of transformers, and particularly relates to a brazing welding device and a brazing welding method. Background Art

[0002] Aluminum wires have good electrical and thermal conductivity, and also have the advantages of low cost and light weight, and are widely used in coil manufacturing.

[0003] During the production and manufacturing of coils, aluminum wires are connected to copper terminals to meet the requirements of electrical connection and installation.

[0004] However, the melting points and expansion coefficients of aluminum wires and copper terminals are different, and the surface of aluminum wires is extremely easy to oxidize to form a high-melting-point oxide film, resulting in many difficulties in the connection between aluminum wires and copper terminals. Summary of the Invention

[0005] This application proposes a brazing welding device to reduce the connection difficulty between aluminum wires and copper terminals. This application also proposes a brazing welding method applicable to the brazing welding device.

[0006] In a first aspect, this application provides a brazing welding device for realizing the brazing connection of a first welded part and a second welded part;

[0007] The brazing welding device includes a welding seat, a pressing member, and an induction heater;

[0008] The first welded part and the second welded part are stacked on the welding seat;

[0009] The pressing member includes a first pressing part and a second pressing part. The first pressing part is used to press the first welded part, and the second pressing part is used to press the second welded part;

[0010] The induction coil of the induction heater is installed on the welding seat, and the induction heater is used to melt the brazing filler metal. The liquid brazing filler metal diffuses with the first welded part and the second welded part to achieve connection.

[0011] Optionally, in the above brazing welding device, the welding seat includes a limiting member for limiting the first welded part in a first direction and a second direction;

[0012] The first direction and the second direction are perpendicular, and the first direction and the second direction are perpendicular to the pressing direction of the pressing member.

[0013] Optionally, in the above brazing welding device, the limiting member is a limiting groove, and the limiting groove includes a first groove wall, a second groove wall, a third groove wall, and a groove bottom;

[0014] The first groove wall and the second groove wall are used to limit the first welding part in the second direction;

[0015] The third groove wall is parallel to the pressing direction and perpendicular to the first direction, and the third groove wall is used to limit the first welding part in the first direction;

[0016] The limiting groove further includes a first notch and a second notch, and the first notch communicates with the second notch;

[0017] The first notch faces the groove bottom, and the first welding part is placed on the groove bottom through the first notch;

[0018] The second notch faces the third groove wall, and the parts of the second welding part and the first welding part that exceed the limiting groove in the first direction protrude through the second notch.

[0019] Optionally, in the above brazing welding device, both the first pressing part and the second pressing part are ceramic pressing blocks;

[0020] and / or

[0021] The first pressing part includes a first pressing groove that cooperates with the first welding part, and the second pressing part includes a second pressing groove that cooperates with the second welding part.

[0022] Optionally, in the above brazing welding device, the pressing part further includes a driving part, and the driving part is used to drive the first pressing part and the second pressing part to move;

[0023] The first pressing part and the second pressing part share the driving part, or the number of driving parts is two, and the two driving parts are respectively connected to the first pressing part and the second pressing part.

[0024] Optionally, in the above brazing welding device, the welding seat is a ceramic seat.

[0025] Optionally, in the above brazing welding device, the induction heater is an intermediate frequency inductor.

[0026] In a second aspect, the present application provides a brazing welding method, including:

[0027] Place a first welding part, a brazing filler metal, and a second welding part on the first welding part;

[0028] The first pressing part and the second pressing part of the pressing part respectively press the first welding part and the second welding part;

[0029] Start the induction heater to melt the solder. The liquid solder diffuses with the first welding part and the second welding part to achieve connection.

[0030] Optionally, in the above brazing welding method, placing the first welding part, the solder, and the second welding part on the first welding part specifically means that

[0031] Place the first welding part on the welding seat;

[0032] Stack the solder on the first welding part;

[0033] Stack the second welding part on the solder.

[0034] Optionally, in the above brazing welding method, before placing the first welding part, the solder, and the second welding part on the first welding part, it further includes:

[0035] Remove the insulation skin to expose the second welding part;

[0036] Machine a groove on the first welding part, and the groove is used to place the solder and the second welding part.

[0037] Optionally, in the above brazing welding method, removing the insulation skin specifically means that

[0038] Cover the tapping area with insulating paper, and wrap 1 - 2 layers of wet asbestos cloth around the root of each wire of the second welding part to protect the root of the wire;

[0039] Place the dust collector and / or the smoke absorber at the welding part of the first welding part and the second welding part, and turn on the dust collector and / or the smoke absorber;

[0040] Cut the wire joint to ensure a flat cut;

[0041] Perform the paint stripping operation through the induction heater.

[0042] Optionally, in the above brazing welding method, performing the paint stripping operation through the induction heater specifically means that

[0043] Adjust the alternating current of the induction heater, put a wire of a preset length into the induction heater, heat the wire until the paint burns to a light gray scale on the surface, stop heating the induction heater, and take out the wire from the induction heater;

[0044] Use pliers to shape the wire to facilitate the welding of the aluminum wire and the copper terminal;

[0045] Clean the burnt enamel of the wire with a metal brush to expose the second welding part, then remove the oxide layer of the second welding part with sandpaper, and finally clean the surface stains of the second welding part with a wet cloth.

[0046] Optionally, in the above brazing welding method, start the induction heater to melt the brazing filler metal. Specifically,

[0047] Press the start button of the induction heater and adjust the alternating current of the induction heater so that the brazing filler metal is heated to the melting point of the brazing filler metal at a preset temperature rise rate and maintain the temperature at the melting point for a preset time to melt the brazing filler metal into a liquid state.

[0048] Optionally, in the above brazing welding method, after starting the induction heater to melt the brazing filler metal and the liquid brazing filler metal diffuses with the first welding part and the second welding part to achieve connection, it further includes:

[0049] Cool the welded part formed by connecting the first welding part, the brazing filler metal and the second welding part to a preset temperature, release the pressing of the first pressing part and the second pressing part on the first welding part and the second welding part, and withdraw the welded part from the induction heater.

[0050] Optionally, in the above brazing welding method, after the welded part is withdrawn from the induction heater, it further includes:

[0051] Perform welding quality inspection and performance testing on the welded part.

[0052] Among them, the welding quality inspection includes:

[0053] Visually observe the sharp corners, burrs and lack of fusion on the surface of the welded part.

[0054] Perform X-ray inspection on the welded part.

[0055] Perform metallographic structure inspection on the welded part.

[0056] The performance testing includes checking the electrical performance of the welded part.

[0057] The brazing welding device provided by the embodiment of the present application includes a welding seat, a pressing member, and an induction heater. A copper terminal is placed on the welding seat, and the welding seat is used to support and position the copper terminal. The aluminum wires are arranged in layers on the copper terminal; the pressing member includes a first pressing portion and a second pressing portion. The first pressing portion is used to press the copper terminal on the welding seat, and the second pressing portion is used to press the aluminum wires on the copper terminal, ensuring that the relative positions of the aluminum wires and the copper terminal do not change during the brazing process; the induction heater generates heat by means of induced current, and the heat generated simultaneously heats the aluminum wires, the filler metal, and the copper terminal. However, the heating temperature is higher than the melting point of the filler metal and lower than the melting points of the aluminum wires and the copper terminal, so that only the filler metal melts during the brazing process, and the filler metal diffuses fully with the aluminum wires and the copper terminal to form a firm metallurgical bond. The brazing welding device disclosed in the present application uses induction welding to replace the traditional flame welding method. There is no open flame during the entire welding process, reducing the risk of fire. At the same time, it will not harm the operator's eyesight or skin, reducing the impact on the physical and mental health of the operator; at the same time, only the filler metal melts during the induction welding process, and the first welding part and the second welding part both remain in a solid state, reducing the welding difficulty; at the same time, induction welding has the advantages of fast heating speed and high efficiency, which can shorten the welding time, shorten the production cycle, improve the production efficiency, and reduce the production cost.

[0058] The present application also discloses a brazing welding method, which is applicable to the brazing welding device described in any of the above solutions. Since the brazing welding device has the above technical effects, the brazing welding method applicable to this brazing welding device also has the same technical effects, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the provided drawings, and the present application can also be applied to other similar scenarios according to the provided drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0060] Figure 1 It is a schematic structural diagram of the brazing welding device provided by the embodiment of the present application;

[0061] Figure 2 It is a flowchart of the brazing welding method provided by the embodiment of the present application:

[0062] Figure 3 It is a flowchart of removing the insulating skin in the brazing welding method provided by the embodiment of the present application.

[0063] Wherein:

[0064] 1 - Welding base; 2 - Compression part; 21 - First compression part; 22 - Second compression part; 3 - Induction coil; 4 - Aluminum wire; 5 - Copper terminal. Detailed implementation manners

[0065] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, rather than limiting the application. The described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0066] It should be noted that for the convenience of description, only the parts related to the relevant application are shown in the drawings. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0067] It should be understood that the "system", "device", "unit" and / or "module" used in the present application are a method for distinguishing different components, elements, parts, portions or assemblies at different levels. However, if other words can achieve the same purpose, the word can be replaced by other expressions.

[0068] As shown in the present application and the claims, unless the context clearly indicates an exception, words such as "a", "an", "one" and / or "the" are not specifically singular and may also include plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the clearly identified steps and elements, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements. The element defined by the statement "including one..." does not exclude the existence of another same element in the process, method, commodity or device including the element.

[0069] Among them, in the description of the embodiments of the present application, unless otherwise specified, " / " means "or". For example, A / B may mean A or B; the "and / or" herein is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present application, "a plurality" means two or more than two.

[0070] Hereinafter, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0071] In the related art, the connection methods between aluminum wires and copper terminals include fusion welding, pressure welding, and brazing.

[0072] When the aluminum wire and the copper terminal are connected by fusion welding, during the welding process, since the melting point of the aluminum wire is lower than that of the copper terminal, when the aluminum wire melts, the copper terminal remains in a solid state. When the copper terminal melts, a lot of the aluminum wire has already melted, increasing the welding difficulty. Moreover, pores are likely to form in the weld seam, the welded joint is brittle, and cracks are likely to occur, resulting in low welding quality and reliability.

[0073] When the aluminum wire and the copper terminal are connected by pressure welding, pressure welding is a solid-phase welding method. During welding, pressure is used to directly and closely contact the surfaces of the aluminum wire and the copper terminal in the solid state, and the temperature of the part to be welded is increased. By adjusting the temperature, pressure, and time, the surfaces of the aluminum wire and the copper terminal are fully diffused to achieve atomic bonding. Pressure welding can improve the joint quality to a certain extent, but it has high requirements for equipment and technology, resulting in a high connection cost between the aluminum wire and the copper terminal.

[0074] Brazing refers to a welding method in which a filler metal with a melting point lower than that of the workpiece and the workpiece are simultaneously heated to the melting temperature of the filler metal, and then the liquid filler metal is used to fill the gaps of the solid workpiece to achieve welded connection. In the related art, when the brazing process is used to connect the aluminum wire and the copper terminal, the traditional gas welding, i.e., the oxygen-acetylene welding process, is adopted. This welding process has an open flame during welding, posing a risk of fire; at the same time, the open flame can cause harm to the operator's vision or skin, which is not conducive to the physical and mental health of the operator. In addition, the brazing method of gas welding has high requirements for the welding skills of the welder, and there are problems such as unstable welding quality, insufficient welding strength, and low welding efficiency during the welding process.

[0075] Figure 1 The following is a schematic structural diagram of the brazing welding device disclosed in the embodiments of the present application. The present application is described by taking the brazing welding device applicable to a dry-type transformer as an example. When the brazing welding device is applicable to a dry-type transformer, the first welded part is the copper terminal 5, the second welded part is the aluminum wire 4, and the brazing welding device is used to realize the brazing connection between the copper terminal 5 and the aluminum wire 4.

[0076] The brazing welding device disclosed in the present application is not only applicable to dry-type transformers, but also can be applicable to other devices that require brazing connection, and all are within the protection scope of the present application.

[0077] Brazing connection requires the use of a filler metal. A filler metal is interposed between the aluminum wire 4 and the copper terminal 5. The melting point of the filler metal is lower than that of the aluminum wire 4 and the copper terminal 5. The filler metal melts, and the liquid filler metal fully diffuses with the aluminum wire 4 and the copper terminal 5 to form a firm metallurgical bond, improving the connection strength between the aluminum wire 4 and the copper terminal 5.

[0078] The brazing welding device disclosed in the present application includes a welding base 1, a pressing member 2, and an induction heater. Among them, a copper terminal 5 is placed on the welding base 1, and the welding base 1 is used to support and position the copper terminal 5. Aluminum wires 4 are arranged in layers on the copper terminal 5. Optionally, the aluminum wires 4 are located on the side of the copper terminal 5 away from the welding base 1; the pressing member 2 includes a first pressing portion 21 and a second pressing portion 22. The first pressing portion 21 is used to press the copper terminal 5, and the second pressing portion 22 is used to press the aluminum wires 4, ensuring that the relative positions of the aluminum wires 4 and the copper terminal 5 do not change during the brazing process; the induction heater includes an induction coil, and the induction coil is installed on the welding base 1, and the induction coil wraps around the copper terminal 5, aluminum wires 4, and brazing material located on the welding base 1.

[0079] The brazing welding device disclosed in the present application uses induction welding. The induction heater generates magnetic lines of force through an alternating current. The magnetic lines of force cut the aluminum wires 4, copper terminal 5, and brazing material, generating eddy currents in the aluminum wires 4, copper terminal 5, and brazing material. The aluminum wires 4, copper terminal 5, and brazing material heat up, the brazing material melts, and the melted brazing material fully diffuses with the aluminum wires 4 and the copper terminal 5 to form a firm metallurgical bond, replacing the traditional flame welding method. There is no open flame during the entire welding process, reducing the risk of fire. At the same time, it will not harm the operator's vision or skin, reducing the impact on the physical and mental health of the operator.

[0080] For the brazing welding device disclosed in the present application, the melting point of the brazing material is lower than that of the first welding part and the second welding part. During the brazing process, only the brazing material melts, and the first welding part and the second welding part both remain in a solid state, reducing the welding difficulty, not easily generating pores, and not causing brittleness at the joint position, improving the consistency of welding quality, enhancing the welding quality and welding reliability, and improving the market competitiveness of the enterprise.

[0081] The brazing welding device disclosed in the present application uses induction welding. Compared with traditional flame welding, induction welding has advantages such as fast heating speed and high efficiency, which can shorten the welding time, reduce the production cycle, improve production efficiency, and reduce production costs. After calculation, the efficiency of the brazing welding device disclosed in the present application can be increased by about 50% compared with traditional flame welding.

[0082] The brazing welding device disclosed in the present application presses the first welding part and the second welding part respectively through the first pressing portion 21 and the second pressing portion 22 of the pressing member 2. Specifically, the first pressing portion 21 presses the copper terminal 5 on the welding base 1, and the second pressing portion 22 presses the aluminum wires 4 on the copper terminal 5 to realize the positioning of the copper terminal 5 and the aluminum wires 4. During the entire welding process, only one operator is required to place the first welding part, the second welding part, and the brazing material. The number of operators is reduced from two to one, reducing the manual labor intensity and labor cost to a certain extent; and the welding process is simple and easy to control.

[0083] In summary, the brazing welding device disclosed in the present application can solve problems such as poor welding quality consistency, low welding efficiency, high welding cost, and unsafe operation in the related art, improve the reliability of the welding quality of the aluminum wire 4 and the copper terminal 5, improve the welding efficiency, reduce the production cost, and improve the safety of the welding process.

[0084] Use the heat generated by the induction heater to quickly heat the parts to be welded. During the heating process, a thermometer (such as an infrared thermometer) can be used to monitor the temperature of the welding area in real time. When the temperature of the welding area reaches the melting point of the filler metal, maintain this temperature for 15 s to 20 s to fully melt the filler metal, and then stop heating. The liquid filler metal wets the base metal, fills the gap between the first welding part and the second welding part, and the liquid filler metal diffuses with the base metal (copper terminal 5 and aluminum wire 4) to form a strong metallurgical bond, improving the welding strength.

[0085] After welding is completed, conduct visual inspection and ultrasonic phased array inspection on the welded part to check whether there are defects such as pores, slag inclusions, and cracks in the welded part. If surface defects are found, repair methods such as re-welding can be used.

[0086] To ensure the stability of the first welding part on the welding seat 1, optionally, in some embodiments, the welding seat 1 includes a limiting member, and the limiting member is used to limit the first welding part in the first direction and the second direction to prevent the first welding part from moving in the first direction and the second direction during the welding process.

[0087] Among them, the first direction and the second direction are perpendicular to each other, the first direction and the second direction are perpendicular to the pressing direction of the pressing member 2, and optionally, the first direction and the second direction are two mutually perpendicular directions in the horizontal plane. As Figure 1 shown, Figure 1 the X direction in is the first direction, the Y direction is the second direction, and the Z direction is the pressing direction. Optionally, the first direction is the length direction of the limiting member, the second direction is perpendicular to the length direction of the limiting member, and the length directions of the first welding part and the second welding part are parallel to the length direction of the limiting member.

[0088] In some embodiments, the limiting member is a limiting groove.

[0089] The limiting groove includes a limiting groove, and the limiting groove includes a first groove wall, a second groove wall, a third groove wall, and a groove bottom. The first groove wall, the second groove wall, the third groove wall, and the groove bottom enclose a space for accommodating the first welding part, the second welding part, and the filler metal.

[0090] Optionally, the space enclosed by the first groove wall, the second groove wall, the third groove wall, and the groove bottom is adapted to the shape of the first welding part. In some embodiments, the welding seat is semi-cylindrical.

[0091] Specifically, the first groove wall and the second groove wall are used to limit the first welding part in the second direction. Optionally, the plane where the first groove wall and the second groove wall are located is parallel to the first direction, and the first groove wall and the second groove wall are arranged in parallel along the second direction.

[0092] The third groove wall is parallel to the pressing direction and perpendicular to the first direction. The third groove wall is located at one end of the first groove wall and the second groove wall along the first direction and can abut against the first welding part to limit the first welding part in the first direction.

[0093] The limiting groove further includes a first notch and a second notch. The first notch communicates with the second notch, where the first notch is opposite to the groove bottom, and the second notch is opposite to the third groove wall.

[0094] The first welding part is placed into the limiting groove through the first notch and is located at the groove bottom. The first welding part can be completely located within the limiting groove, or one end of the first welding part away from the third groove wall can also extend out of the limiting groove through the second notch. The part of the second welding part whose length along the first direction exceeds that of the limiting groove extends out through the second notch.

[0095] In some embodiments, a groove is provided on one side of the first welding part facing the first notch. The groove is used to place the filler metal and the second welding part. Optionally, the dimensions of the filler metal along the first direction and the second direction are equal to the dimensions of the groove along the first direction and the second direction, and the dimension of the second welding part along the second direction is equal to the dimension of the groove. In some embodiments, the dimension of the groove is 0.3 mm × 12 mm × 40 mm, and the dimension of the filler metal is 0.3 mm × 12 mm × 20 mm. Two pieces of filler metal arranged in a stacked manner along the pressing direction are placed in the groove to avoid the situation of filler metal accumulation or insufficient filling, and improve the welding quality and welding efficiency.

[0096] The structure of the limiting part is not limited to the above embodiments. Other structures that can achieve the limitation of the first welding part in the first direction and the second direction are within the protection scope of the present application.

[0097] Optionally, the filler metal is zinc-aluminum filler metal (Zn-15Al). Zn-15Al has good fluidity and wettability to copper and aluminum, can achieve good welding effects at lower temperatures, can effectively remove the oxides on the surfaces of copper and aluminum, and promote the spreading and filling of the filler metal.

[0098] The filler metal can also be a combination of one or several of tin, nickel, and zinc, or can also be a combination of at least one or two of the metals gold and silver.

[0099] To prevent the filler metal from flowing unevenly, the brazing welding device disclosed in the present application needs to be tilted during welding. After tilting, the included angle between the length direction of the second welding part and the horizontal plane is 10° - 20°, and the position where the second welding part is welded to the first welding part is lower than the position where the second welding part is far from the first welding part.

[0100] Optionally, the first pressing part 21 and the second pressing part 22 are ceramic pressing blocks. As Figure 1 shown, the first pressing part 21 and the second pressing part 22 are plate-like structures along a direction parallel to the pressing direction and perpendicular to the first direction, and the plate-like structures are made of ceramic materials.

[0101] The first pressing part 21 and the second pressing part 22 are not limited to ceramic materials, and may also be other non-metallic materials, all within the protection scope of this application.

[0102] The shapes of the first pressing part 21 and the second pressing part 22 are not limited to plate-like shapes, and may also be other structural forms that can press the first welding part and the second welding part, all within the protection scope of this application.

[0103] To optimize the pressing effect of the first pressing part 21 and the second pressing part 22 on the first welding part and the second welding part, the first pressing part 21 includes a first pressing groove adapted to the shape of the first welding part, and the second pressing part 22 includes a second pressing groove adapted to the shape of the second welding part.

[0104] The first pressing groove, the second pressing groove cooperate with the limiting groove and the groove to improve the pressing effect on the first welding part and the second welding part.

[0105] The movement of the first pressing part 21 and the second pressing part 22 can be realized by manual driving and cooperating with a locking part.

[0106] The movement of the first pressing part 21 and the second pressing part 22 can also be realized by a driving part, and the driving part drives the first pressing part 21 and the second pressing part 22 to move in a direction close to or away from the welding seat 1.

[0107] When the driving part drives the first pressing part 21 and the second pressing part 22 to move in a direction close to the welding seat 1, the first pressing part 21 and the second pressing part 22 respectively press the first welding part and the second welding part; when the driving part drives the first pressing part 21 and the second pressing part 22 to move in a direction away from the welding seat 1, the first pressing part 21 and the second pressing part 22 respectively release the pressing on the first welding part and the second welding part.

[0108] Optionally, the welding seat 1 is a ceramic seat.

[0109] In some embodiments, the first pressing part 21 and the second pressing part 22 share a driving part, that is, the pressing part 2 includes a driving part, and the driving part drives the first pressing part 21 and the second pressing part 22 to move simultaneously, realizing the synchronous movement of the first pressing part 21 and the second pressing part 22.

[0110] In some embodiments, the pressing member 2 includes two driving members which are respectively connected to the first pressing portion 21 and the second pressing portion 22. The two driving members respectively drive the first pressing portion 21 and the second pressing portion 22 to move. In this embodiment, the first pressing portion 21 and the second pressing portion 22 can move synchronously or asynchronously.

[0111] Optionally, the driving member is a telescopic cylinder.

[0112] Optionally, the induction heater is an intermediate frequency inductor.

[0113] The induction heater is not limited to the intermediate frequency inductor, and can also be other devices capable of realizing induction welding, which are all within the protection scope of this application.

[0114] This application also discloses a brazing welding method applicable to the brazing welding device described in any of the above solutions.

[0115] The brazing welding method disclosed in this application includes:

[0116] Placing the first welding piece, the brazing filler metal and the second welding piece on the welding seat 1;

[0117] The first pressing portion 21 and the second pressing portion 22 of the pressing member 2 respectively press the first welding piece and the second welding piece;

[0118] Starting the induction heater to melt the brazing filler metal, and the liquid brazing filler metal diffuses with the first welding piece and the second welding piece to achieve connection.

[0119] Placing the first welding piece, the brazing filler metal and the second welding piece on the welding seat 1 specifically means that before the first welding piece, the brazing filler metal and the second welding piece are placed on the welding seat 1, they are stacked, and the whole formed by stacking the first welding piece, the brazing filler metal and the second welding piece is placed on the welding seat 1. It can also be that the first welding piece is first placed on the welding seat 1, and then the brazing filler metal and the second welding piece are stacked on the first welding piece in sequence. It can also be that the first welding piece and the brazing filler metal are first assembled, and then the second welding piece is placed on the brazing filler metal.

[0120] The first pressing portion 21 and the second pressing portion 22 of the pressing member 2 respectively press the first welding piece and the second welding piece to complete the preparatory work before welding.

[0121] After the above work is completed, start the induction heater to melt the brazing filler metal, and the liquid brazing filler metal diffuses with the first welding piece and the second welding piece to achieve connection.

[0122] The brazing welding method disclosed in this application is applicable to the brazing welding device described in any of the above-mentioned solutions. Since the brazing welding device has the above technical effects, the brazing welding method applicable to this brazing welding device also has the same technical effects, which will not be elaborated here.

[0123] The first welding part is first placed on the welding seat 1, and then the brazing filler metal and the second welding part are stacked on the first welding part in sequence. Specifically, first place the first welding part on the welding seat 1, with the non-welding end of the first welding part abutted against the third groove wall, then place the brazing filler metal on the first welding part, and finally place the second welding part on the brazing filler metal. The separate placement method of the first welding part, the brazing filler metal, and the second welding part disclosed in this embodiment can reduce the difficulty of placing the first welding part, the brazing filler metal, and the second welding part on the welding seat 1.

[0124] Before placing the first welding part, the brazing filler metal, and the second welding part on the welding seat 1, it further includes:

[0125] Remove the insulating skin to expose the second welding part;

[0126] Machine a groove for installing the brazing filler metal on the first welding part. The groove is used to place the brazing filler metal and the second welding part.

[0127] Removing the insulating skin is to perform surface treatment of removing paint on the wire before welding. Specifically, it includes:

[0128] Cover the tapping area with insulating paper, and wrap 1 - 2 layers of wet asbestos cloth (as long as it doesn't drip water) around the root of each wire to be welded to protect the root of the wire to be welded;

[0129] Turn on the dust removal / smoking device and place the dust removal / smoking device at the welding part of the aluminum wire 4 to be welded and the copper terminal 5;

[0130] Cut the aluminum wire joint to ensure that the cut is flat, with a tolerance requirement of ±0.1 mm;

[0131] Perform the paint removal operation through an induction heater.

[0132] Performing the paint removal operation through an induction heater, specifically, adjust the alternating current of the induction heater, put the aluminum wire with a length of 20 mm - 30 mm into the induction heater, heat the aluminum wire until the paint burns to a light gray scale on the surface, stop heating, and take out the aluminum wire from the induction heater;

[0133] Use pliers to shape the aluminum wire 4, twist the width direction of the aluminum wire 4 to the horizontal to facilitate the welding of the aluminum wire 4 and the copper terminal 5;

[0134] Clean the burned paint of the aluminum wire with a metal brush, then remove the oxide layer of the paint removal part of the aluminum wire 4 with sandpaper, and finally clean the surface stain of the wire with a wet cloth so that the part of the aluminum wire to be welded is bright.

[0135] After the above steps are completed, use a vacuum cleaner to adsorb foreign matters on the surface of the copper terminal 5, and then use a dry cloth to clean the surface of the copper terminal 5 again.

[0136] Place the copper terminal 5 on the welding seat 1, and the end face of the non-welding end of the copper terminal 5 completely abuts against the third groove wall of the welding seat 1. Place two zinc-aluminum solder sheets on the copper terminal 5, then place the aluminum wire 4 to be welded on the zinc-aluminum solder sheets, and finally start the pressing member 2 to press and fix the copper terminal 5 and the aluminum wire 4 through the first pressing portion 21 and the second pressing portion 22 respectively, so as to prevent displacement during the welding process.

[0137] The reference current of the induction heater for removing paint is as follows:

[0138]

[0139] A groove is formed in the first welding member. The dimensions of the groove in the first direction and the second direction are equal to the dimensions of the solder in the first direction and the second direction. After the solder is embedded in the groove, the solder can fill the groove along the plane where the first direction and the second direction are located, and the molten solder can fill the gap between the first welding member and the second welding member, improving the welding quality and the reliability of the welding.

[0140] Optionally, the depth of the groove in the pressing direction is at least twice the thickness of the solder. The selection of the thickness of the groove and the solder can ensure that the situation of solder accumulation or insufficient solder filling is avoided.

[0141] If there is too little solder, it is easy to have the problem of insufficient solder. On the one hand, it cannot effectively fill the gap between the first welding member and the second welding member. On the other hand, it cannot play the role of spacing the first welding member and the second welding member, so that an electrochemical reaction will occur between the copper terminal 5 and the aluminum wire 4 after welding, shortening the service life of the connection position.

[0142] If there is too much solder, it is easy to have the problem of solder accumulation. On the one hand, it causes waste of materials. On the other hand, it causes the solder thickness between the copper terminal 5 and the aluminum wire 4 to be too large, resulting in an increase in the voltage drop at the welding position and affecting the electrical performance of the welding position.

[0143] Optionally, the solder can be in a sheet structure or a wire structure.

[0144] When the solder is in a wire structure, the zinc-aluminum solder is arranged side by side in the groove along the second direction; along the pressing direction, the zinc-aluminum solder can be at least two layers.

[0145] In the embodiment where the solder is in a wire structure, the bottom of the limiting groove has an arc-shaped groove adapted to the shape of the solder.

[0146] Start the induction heater to melt the solder. Specifically,

[0147] Press the start button of the induction heater and adjust the alternating current of the induction heater so that the solder heats up to the melting point of the solder at a preset temperature rise rate and maintains the temperature at the melting point for a preset time, causing the solder to melt into a liquid state.

[0148] Adjust the alternating current. Specifically, adjust the welding current according to the following table.

[0149]

[0150] Closely monitor the temperature change of the solder during the heating process. Taking the zinc-aluminum solder (Zn-15Al) as an example, the solder heats up to 400°C - 450°C at a preset temperature rise rate, approaching the melting point of the zinc-aluminum solder (Zn-15Al). After the copper terminal 5 turns red and the solder just melts, maintain the temperature of 400°C - 450°C for 15S - 20S to fully melt the solder. During this period, use a Φ1.2 zinc-aluminum flux-cored wire for appropriate filling, and the solder and the base material diffuse sufficiently to form a firm metallurgical bond, improving the welding strength.

[0151] Closely monitoring the temperature change of the solder during the heating process is achieved through an infrared thermometer.

[0152] Optionally, the preset temperature rate ≤ 15°C / s.

[0153] After the heat preservation ends, turn off the induction heater, withdraw the workpiece, and the welding is completed.

[0154] After starting the induction heater to melt the solder and the liquid solder diffuses with the first welding part and the second welding part to achieve connection, it further includes:

[0155] Cool the welded part formed by connecting the first welding part, the solder, and the second welding part to a preset temperature, release the pressing of the first pressing part 21 and the second pressing part 22 on the first welding part and the second welding part, and withdraw the welded part from the induction heater.

[0156] Cooling can be achieved by using compressed air to cool the welded part to the preset temperature. In some embodiments, the preset temperature is 80°C.

[0157] The cooling method can also be water cooling or natural cooling.

[0158] After cooling, use a metal brush or sandpaper to clean the surface oxide layer of the welding part until the surface of the welding part is shiny.

[0159] After the welded part is withdrawn from the induction heater, it further includes:

[0160] Conduct welding quality inspection and performance testing on the welded part.

[0161] Among them, the welding quality inspection includes:

[0162] Visually inspect the sharp corners, burrs and lack of welding on the surface of the welded part;

[0163] Perform X-ray inspection on the welded part. Optionally, an X-ray non-destructive detector is used for the X-ray inspection;

[0164] Perform metallographic structure inspection on the welded part. Optionally, a metallurgical microscope and an electron scanning electron microscope are used for the metallographic structure inspection to check whether there are defects such as pores, slag inclusions and cracks at the welding site;

[0165] The performance test includes checking the electrical performance of the welded part. By means of resistance test, check whether the welding site meets the electrical performance requirements of the dry-type transformer to ensure the stability and reliability of current transmission.

[0166] If defects are found on the surface, methods such as repair welding can be used for repair.

[0167] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles, and is not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. The scope of the application involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above application concept. For example, the technical solutions formed by mutual replacement of the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A brazing welding device, characterized in that, For realizing the brazing connection between the first welded part and the second welded part; The brazing welding device includes a welding seat (1), a pressing member (2) and an induction heater; The first welded part and the second welded part are stacked on the upper layer of the welding seat (1); The pressing member (2) includes a first pressing part (21) and a second pressing part (22). The first pressing part (21) is used for pressing the first welded part, and the second pressing part (22) is used for pressing the second welded part; The induction coil (3) of the induction heater is installed on the welding seat (1), and the induction heater is used to melt the brazing filler metal. The liquid brazing filler metal diffuses with the first welded part and the second welded part to achieve connection.

2. The brazing welding device according to claim 1, characterized in that, The welding seat (1) includes a limiting member, and the limiting member is used for limiting the first welded part in the first direction and the second direction; The first direction and the second direction are perpendicular, and the first direction and the second direction are perpendicular to the pressing direction of the pressing member (2).

3. The brazing welding device according to claim 2, wherein, The limiting member is a limiting groove, and the limiting groove includes a first groove wall, a second groove wall, a third groove wall and a groove bottom; The first groove wall and the second groove wall are used for limiting the first welded part in the second direction; The third groove wall is parallel to the pressing direction and perpendicular to the first direction, and the third groove wall is used for limiting the first welded part in the first direction; The limiting groove further includes a first groove opening and a second groove opening, and the first groove opening communicates with the second groove opening; The first groove opening is opposite to the groove bottom, and the first welded part is placed on the groove bottom through the first groove opening; The second groove opening is opposite to the third groove wall, and the part of the second welded part and the first welded part that exceeds the limiting groove in the first direction extends out through the second groove opening.

4. The brazing welding device according to claim 1, characterized in that, Both the first pressing part (21) and the second pressing part (22) are ceramic pressing blocks; And / or The first pressing part (21) includes a first pressing groove that cooperates with the first welded part, and the second pressing part (22) includes a second pressing groove that cooperates with the second welded part.

5. The brazing welding device according to any one of claims 1-4, characterized in that, The pressing member (2) further includes a driving member, and the driving member is used for driving the first pressing part (21) and the second pressing part (22) to move; The first pressing part (21) and the second pressing part (22) share the driving member, or the number of driving members is two, and the two driving members are respectively connected to the first pressing part (21) and the second pressing part (22).

6. The brazing welding device according to any one of claims 1-4, characterized in that, The welding seat (1) is a ceramic seat.

7. The brazing welding device according to claim 1, characterized in that The induction heater is an intermediate frequency inductor.

8. A brazing welding method, characterized in that, Including: Placing the first welded part, the brazing filler metal and the second welded part on the welding seat (1); The first pressing part (21) and the second pressing part (22) of the pressing member (2) respectively press the first welded part and the second welded part; Starting the induction heater to melt the brazing filler metal, and the liquid brazing filler metal diffuses with the first welded part and the second welded part to achieve connection.

9. The brazing welding method according to claim 8, characterized in that, Placing the first welded part, the brazing filler metal and the second welded part on the welding seat (1) specifically means Place the first welding part on the welding base (1); Stack the filler metal on the first welding part; Stack the second welding part on the filler metal.

10. The brazing welding method according to claim 8, characterized in that, Before placing the first welding part, the filler metal, and the second welding part on the first welding part, it further includes: Remove the insulation skin to expose the second welding part; Machine a groove on the first welding part, and the groove is used to place the filler metal and the second welding part.

11. The brazing welding method according to claim 10, characterized in that, Specifically, removing the insulation skin is: Cover the tapping area with insulating paper, and wrap 1 - 2 layers of wet asbestos cloth around the root of each wire of the second welding part to protect the root of the wire; Place the dust collector and / or the smoke absorber at the welding part of the first welding part and the second welding part, and turn on the dust collector and / or the smoke absorber; Cut the wire joint to ensure a smooth cut; Perform the paint removal operation through an induction heater.

12. The brazing welding method according to claim 11, wherein Specifically, performing the paint removal operation through an induction heater is: Adjust the alternating current of the induction heater, put a wire of a preset length into the induction heater, heat the wire until the paint burns to a light gray scale on the surface, stop heating the induction heater, and take out the wire from the induction heater; Use pliers to shape the wire to facilitate the welding of the aluminum wire and the copper terminal; Clean the burnt paint of the wire through a metal brush to expose the second welding part, then remove the oxide layer of the second welding part with sandpaper, and finally clean the surface stain of the second welding part with a wet rag.

13. The brazing welding method according to claim 8, characterized in that, Start the induction heater to melt the filler metal. Specifically: Press the start button of the induction heater, adjust the alternating current of the induction heater, so that the filler metal heats up to the melting point of the filler metal at a preset temperature rise rate, and maintain the temperature at the melting point for a preset time to make the filler metal melt into a liquid state.

14. The brazing welding method according to claim 8, characterized in that, After starting the induction heater to melt the filler metal, and after the liquid filler metal diffuses with the first welding part and the second welding part to achieve connection, it further includes: Cool the welded part formed by connecting the first welding part, the filler metal, and the second welding part to a preset temperature, release the pressing of the first pressing part (21) and the second pressing part (22) on the first welding part and the second welding part, and withdraw the welded part from the induction heater.

15. The brazing welding method according to claim 14, characterized in that, After the welded part is withdrawn from the induction heater, it further includes: Perform welding quality inspection and performance testing on the welded part, Among them, the welding quality inspection includes: Visually observe the sharp corners, burrs, and lack of fusion on the surface of the welded part; Perform X - ray inspection on the welded part; Perform metallographic structure inspection on the welded part; The performance testing includes checking the electrical performance of the welded part.

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