Large-thickness multi-layer soft copper bar diffusion welding device assisted by induction heating

Abstract

The utility model discloses an induction heating assisted large-thickness multi-layer soft copper bar diffusion welding device, which relates to the technical field of copper bar welding and comprises a hydraulic machine, a movable sliding table, an upper tool assembly, a lower tool assembly and a graphite pressure head, the hydraulic machine is connected with the upper tool assembly through a pressure rod, and the movable sliding table is movably connected with the lower tool assembly. An upper graphite pressure head and a lower graphite pressure head are arranged between the upper tool assembly and the lower tool assembly, the upper graphite pressure head and the lower graphite pressure head can perform pressure applying and resistance heating on the upper end face and the lower end face of the soft copper bar, and the induction heating assembly is located on the side faces of the upper graphite pressure head, the lower graphite pressure head and the soft copper bar and used for heating the graphite pressure heads and the soft copper bar from the side faces. The induction heating assembly is additionally arranged on the basis of conventional copper bar diffusion welding, resistance heating and induction heating are combined, the heating efficiency of large-thickness copper bar welding is improved, temperature nonuniformity in the large-thickness copper bar welding process is relieved, and the welding quality consistency and stability are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to soft copper bar welding technical field more specifically, it relates to a kind of induction heating auxiliary large thickness multilayer soft copper bar diffusion welding device. BACKGROUND

[0002] Flexible soft copper bar has very wide application in electric power transmission industry with its flexible connection characteristics.Flexible soft copper bar is generally composed of multiple copper foils, and the end is connected as a whole by welding, as shown in Figure 1 Before and after welding state contrast is shown, the left side of the diagram is before welding, and the right side of the diagram is after welding.However, since the multi-layer structure of soft copper bar requires reliable connection between each layer, conventional welding method is difficult to apply.Therefore, diffusion welding is generally used as the main connection method in the current industry.Diffusion welding, as a solid-phase welding technology, is a method of connecting by atomic diffusion at the contact surface of the workpiece under high temperature and high pressure, with the characteristics of low welding temperature, small welding deformation and reliable welding quality.In the diffusion welding connection of soft copper bar, in order to improve production efficiency, the workpiece is heated quickly by resistance, and pressure is applied by graphite pressure head with good conductivity and rigidity.The entire welding process of conventional soft copper bar with small thickness can be completed within a few seconds.

[0003] However, when the thickness of soft copper bar increases to a certain extent, the problems of low heating efficiency and uneven heating become prominent, making the welding process difficult.Low heating efficiency is mainly due to the relatively low resistivity of copper, resulting in limited resistance heat, and the excellent thermal conductivity of copper also causes a large amount of heat to flow away from the welding area quickly.Therefore, in order to maintain sufficient welding temperature, process current must be increased and heating time must be prolonged.In addition, uneven heating is due to the fact that resistance heat is mainly concentrated on the contact surface between copper bar and graphite pressure head, and as the thickness of copper bar increases, the time required for heat conduction from the contact surface to the center also increases, resulting in a large temperature difference in the thickness direction of copper bar.This temperature difference further leads to inconsistent welding quality between each layer of copper bar.

[0004] In order to overcome these difficulties in the welding process of large thickness soft copper bar, a new type of heating scheme needs to be developed. UTILITY MODEL CONTENT

[0005] In view of this problem in actual application, the utility model aims to provide a kind of induction heating auxiliary large thickness multilayer soft copper bar diffusion welding device, which aims to improve the heating efficiency of soft copper bar and effectively alleviate the unevenness in the heating process, to ensure the stability and consistency of welding quality, and the specific scheme is as follows:

[0006] The utility model provides an induction heating auxiliary diffusion welding device of big thickness multilayer soft copper bar, including hydraulic press, mobile slide, upper tooling assembly, lower tooling assembly, two graphite pressure head, the hydraulic press is connected the upper tooling assembly through the pressure rod, the mobile slide is movablely connected with the lower tooling assembly, and the upper tooling assembly and the lower tooling assembly are equipped with two upper and lower opposite graphite pressure heads, and the upper and lower graphite pressure heads can press and resistance heating to the upper and lower end surfaces of the soft copper bar, further including induction heating assembly, the induction heating assembly is located at the side of two graphite pressure heads and soft copper bar, and is used for inducting heating to two graphite pressure heads and soft copper bar from the side.

[0007] Further, the induction heating assembly includes a coil cable and an induction heating coil electrically connected to the coil cable, and the induction heating coil is located at the side of the upper and lower graphite pressure heads and the soft copper bar.

[0008] Further, the heating area of the induction heating coil includes an upper part, a middle part and a lower part, and the upper and lower parts are used for heating the upper and lower graphite pressure heads from the side respectively, and the middle part is used for heating the copper bar from the side.

[0009] Further, the induction heating coil and the coil cable are provided with two groups, and the two induction heating coils are arranged vertically side by side.

[0010] Further, the induction heating coil has a shape of a rectangle.

[0011] Further, the induction heating assembly further includes a fixed base, and the induction heating coil and the coil cable are fixed to the fixed base.

[0012] Further, the fixed base is movable along a direction close to or away from the graphite pressure head.

[0013] Compared with the prior art, the utility model has the beneficial effects as follows:

[0014] On the basis of the conventional copper bar diffusion welding, the utility model introduces an induction heating assembly, combines resistance heating and induction heating, realizes diffusion welding with resistance and induction, improves the heating efficiency of the big thickness copper bar welding, saves energy consumption to a certain extent, relieves the temperature inhomogeneity in the process of the big thickness copper bar welding, reduces the welding difficulty of the big thickness copper bar, and improves the consistency and stability of the welding quality. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is the state schematic view before and after the soft copper bar welding.

[0016] Figure 2 It is the overall schematic view of the utility model device.

[0017] Figure 3 is a structural schematic view of the induction heating assembly in the embodiment of the utility model;

[0018] Figure 4 is a state schematic view of the induction heating coil in the utility model located at the side of the graphite pressure head and the soft copper bar;

[0019] Figure 5 is a front view of the induction heating coil in the embodiment of the utility model.

[0020] Reference signs: 1, hydraulic machine; 2, pressure rod; 3, movable sliding table; 4, upper tooling assembly; 5, lower tooling assembly; 6, graphite pressure head; 7, induction heating assembly; 71, coil cable; 72, induction heating coil; 73, fixed base; 8, upper heating area; 9, middle heating area; 10, lower heating area; 11, welding area;

[0021] 100, copper bar. DETAILED DESCRIPTION

[0022] The technical scheme in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model, obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments.

[0023] As shown in Figure 2 An induction heating assisted large-thickness multilayer soft copper bar diffusion welding device, comprising a hydraulic machine 1, a movable sliding table 3, an upper tooling assembly 4, a lower tooling assembly 5, two graphite pressure heads 6, the hydraulic machine 1 is connected with the upper tooling assembly 4 through the pressure rod 2, the movable sliding table 3 is fixed below the hydraulic machine 1, the lower tooling assembly 5 is movably connected on the movable sliding table 3, and the lower tooling assembly 5 is located below the upper tooling assembly 4, wherein the lower tooling assembly 5 can move along the axial direction of the movable sliding table 3. It should be noted that the movable sliding table 3 is prior art, and the application does not involve improvement thereof, so the structure and working principle thereof will not be described again.

[0024] Two upper and lower graphite pressure heads 6 are arranged between the upper tooling assembly 4 and the lower tooling assembly 5, and the upper and lower graphite pressure heads 6 can press and resistance heat the upper and lower end faces of the soft copper bar 100.

[0025] The process of heating the workpiece by resistance heating is as follows: after the assembled multi-layer soft copper bar 100 is placed between the upper and lower graphite pressure heads 6, the graphite pressure heads 6 are connected with electric current, and the resistance heat is generated in the entire circuit when the electric current flows through the graphite pressure heads 6 and the soft copper bar 100. The greater the resistance, the more heat is generated. In the circuit, there are several main resistances: the internal resistance of graphite, the internal resistance of copper foil, the contact resistance between copper foils, and the contact resistance between copper foils and graphite. Since the resistivity of graphite is much higher than that of copper, the heat generated in the graphite is also much greater than that generated in the copper foil. As the heating process proceeds, the plastic deformation of the copper foil leads to a smaller and smaller contact resistance between the copper foils, and the resistance heat between the copper foils also becomes smaller and smaller. The contact resistance between the graphite and the copper foils does not decrease significantly due to the rigidity of the graphite. Therefore, the main heat generation areas in the resistance heating process are the graphite body and the contact surface between the graphite and the copper bar. As the heating proceeds, the temperature of the graphite rises significantly, and the highest temperature is distributed on the contact surface between the graphite and the copper bar. The heat is gradually conducted to the middle of the copper bar, thereby achieving heating of the copper bar.

[0026] However, when the thickness of the copper bar 100 increases, the temperature of the copper bar 100 in the thickness direction becomes non-uniform due to the limitation of the heat conduction rate and the heat dissipation of the copper bar 100 to the outside of the welding area 11, showing a situation of high temperature on the upper and lower sides and low temperature in the middle. Therefore, the problems of low heating efficiency and uneven heating occur.

[0027] Therefore, the utility model device further includes an induction heating assembly 7, which is located on the side of the two graphite pressure heads 6 and the soft copper bar 100, and is used for heating the two graphite pressure heads 6 and the soft copper bar 100 from the side, thereby achieving heating of the workpiece by induction heating.

[0028] After the induction heating assembly 7 is added, there are two heat sources: one is the resistance heat generated by the graphite pressure heads 6 and the copper bar 100, and the other is the induction coil located on the side of the copper bar 100 and the graphite pressure heads 6. After the induction heating assembly 7 is added, the problems of low heating efficiency and uneven heating existing in the existing resistance heating diffusion welding equipment can be solved.

[0029] Specifically:

[0030] For example, Figure 3As shown, the induction heating assembly 7 includes a coil cable 71, an induction heating coil 72, and a fixed base 73. The induction heating coil 72 is electrically connected to the coil cable 71, and is located at the side of the upper and lower graphite pressing heads 6 and the soft copper bar 100. The induction heating coil 72 and the coil cable 71 are both fixed on the fixed base 73. Preferably, the induction heating coil 72 and the induction heating coil 72 and the coil cable 71 are provided with two groups, and the two induction heating coils 72 are arranged vertically side by side. Moreover, the shape of the induction heating coil 72 matches the shape of the graphite pressing head 6 and the soft copper bar 100, and is a rectangle, which is conducive to heating.

[0031] In combination Figure 4 When the induction heating coil 72 is located at the designated position at the side of the graphite pressing head 6 and the soft copper bar 100, the two induction heating coils 72 are in contact with the side of the two graphite pressing heads 6 and the copper bar 100 welding area 11, and heat the side by induction heating. Among them, the welding area 11 is the position that needs to be welded, and is also the main area that needs to be heated.

[0032] In combination Figure 5 The heating area of the induction heating coil 72 includes three parts, namely the upper heating area 8, the middle heating area 9, and the lower heating area 10. The upper heating area 8 is used to heat the upper graphite pressing head 6 from the side, the lower heating area 10 is used to heat the lower graphite pressing head 6 from the side, and the middle heating area 9 is used to heat the copper bar 100 from the side.

[0033] Due to the characteristics of induction heating, heat is mainly generated on the outer surface of the graphite pressing head 6 and the copper bar 100 close to the induction heating coil 72, and gradually conducts heat to the inside. The introduction of the induction heating coil 72 for auxiliary heating has two main benefits: first, the introduction of an additional heat source improves the heating rate of the graphite pressing head 6 and the copper bar 100, and the heating efficiency is improved, thereby reducing the overall heat loss during the heating process; second, auxiliary heating from the side of the copper bar to the middle area of the copper bar can effectively alleviate the temperature non-uniformity of the copper bar in the thickness direction, thereby improving the consistency of the welding quality between the layers of the copper bar.

[0034] In addition, in order to realize the mobility of the induction heating coil 72, the fixed base 73 can be moved along the direction close to and away from the graphite pressing head 6. In one possible embodiment, the fixed base 73 can be moved manually; or it can be moved automatically, such as by a hydraulic cylinder or the like. The present application does not limit this.

[0035] The specific implementation principle of the utility model is: when welding, first, the assembled multi-layer soft copper bar 100 is placed between the upper and lower graphite pressure heads 6, the hydraulic machine 1 presses the upper tool assembly 4 through the pressure rod 2, the graphite pressure head 6 reliably clamps the soft copper bar 100, then the induction heating assembly 7 is moved to the specified position of the side surface of the graphite pressure head 6 and the soft copper bar 100, the resistance heating and induction heating are started, the welding area is continuously heated until the welding is completed. Finally, the heating power is turned off, the induction heating assembly 7 is removed and the hydraulic machine is opened, and the welded soft copper bar 100 is taken out.

[0036] The above is only the preferred embodiment of the utility model, the protection scope of the utility model is not only limited to the above-mentioned embodiment, and all technical schemes under the idea of the utility model belong to the protection scope of the utility model. It should be pointed out that for ordinary skilled person in the art, some improvements and decorations without departing from the principle of the utility model are also regarded as the protection scope of the utility model.

Claims

1. An induction heating assisted diffusion welding device for large thickness multi-layer soft copper bar, comprising a hydraulic machine, a moving slide, an upper tooling assembly, a lower tooling assembly, two graphite pressure heads, the hydraulic machine being connected with the upper tooling assembly through a pressure rod, the moving slide being movably connected with the lower tooling assembly, the upper tooling assembly and the lower tooling assembly being provided with two graphite pressure heads arranged oppositely, the upper and lower graphite pressure heads being capable of pressing and resistance heating the upper and lower end surfaces of the soft copper bar, characterized in that: it further comprises an induction heating assembly, the induction heating assembly being located at the side of the two graphite pressure heads and the soft copper bar, and being used for induction heating the two graphite pressure heads and the soft copper bar from the side. The induction heating assembly comprises a coil cable and an induction heating coil, the induction heating coil being electrically connected with the coil cable, and the induction heating coil being located at the side of the upper and lower graphite pressure heads and the soft copper bar.

2. The induction heating assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 1, wherein, The heating area of the induction heating coil comprises upper, middle and lower parts, the upper and lower parts being respectively used for heating the upper and lower graphite pressure heads from the side, and the middle part being used for heating the copper bar from the side.

3. The induction heating assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 2, wherein, The induction heating coil and the coil cable are provided with two groups, and the two induction heating coils are arranged vertically side by side.

4. The inductively heated assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 2, wherein, The shape of the induction heating coil is a square.

5. The inductively heated assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 2, wherein, The induction heating assembly further comprises a fixed base, and the induction heating coil and the coil cable are fixed on the fixed base.

6. The inductively heated assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 1, wherein, The fixed base is movable along the direction of approaching and moving away from the graphite pressure head.

7. The induction heating assisted large thickness multilayer soft copper bar diffusion bonding apparatus of claim 6, wherein, ​

Images