A welding device for welding a circuit breaker contact assembly lug and a welding process thereof

Abstract

This invention provides a welding process for the welding tabs of circuit breaker contact assemblies, including a welding device and a welding method. This process, through the cooperation of an upper electrode, a lower electrode, a contact support moving and positioning device, and a welding tab moving and positioning device, automatically welds the welding tabs on the contact support, eliminating the need for manual placement of the contact support and manual welding. Furthermore, the relatively low melting point of the solder and the fact that the melted solder fills the welding surfaces of the contacts and support, forming a multi-element alloy, ensure the welding quality of the contact assembly, resulting in a high-quality joint strength. This invention can improve production efficiency, reduce production costs, and improve welding quality.

Description

Technical Field

[0001] This invention relates to the field of welding technology, specifically a welding apparatus and welding process for welding contact pieces of circuit breaker assemblies. Background Technology

[0002] A miniature circuit breaker (MCB), also known as a small circuit breaker, is suitable for overload and short-circuit protection of AC 50 / 60Hz lines with a rated voltage of 230 / 400V and a rated current up to 63A. It can also be used for infrequent switching of circuits under normal conditions. Miniature circuit breakers are mainly used in various locations including industrial, commercial, high-rise, and residential buildings.

[0003] The contact assembly is one of the key contact components of an electrical switch. The main performance and service life of an electrical switch largely depend on the welding quality of the contact assembly. Besides the quality of the raw materials, the welding process and method play a crucial role in the quality of welded contact assemblies. Due to their relatively complex shape and small size, miniature circuit breaker contacts generally employ traditional metal electrode resistance welding. Depending on the application requirements, the support of the contact stationary assembly is typically made of copper alloy or copper-plated steel strip, while the contacts are made of AgC material. When using copper alloy, its good conductivity results in less resistance heat during metal electrode welding, leading to suboptimal welding quality between the copper parts and the contacts on the support. Therefore, it is necessary to add solder to lower the welding temperature. The relatively low melting point of the solder and its ability to fill the welding surface of the contacts and support after melting, forming a multi-element alloy, ensure the welding quality of the contact assembly.

[0004] Traditional methods for adding solder pads to AgC contacts typically involve manual placement or a solder pad coating process. Manual placement cannot be automated, resulting in low production efficiency and poor placement accuracy, affecting the stability of the weld quality. Solder pad coating of AgC contacts also involves manually placing the solder pads and then heating them to bond them to the contact point. This method is costly, and the solder pads often develop closed voids, preventing complete gas escape during welding and creating micro-voids on the weld surface, further impacting weld quality stability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a welding process for the welding tabs of miniature circuit breaker components, specifically including a welding method and a welding apparatus. The technical solution adopted by this invention is as follows:

[0006] Miniature circuit breaker contact assemblies include contact supports and solder strips. The solder strips are generally made of Ag-based or other alloy materials with a width of 3-10 mm, a thickness of 0.03-0.2 mm, and a length greater than 200 mm, such as Ag15CuP, AgCu28, etc.

[0007] In a first aspect, the welding process of the present invention includes a welding apparatus having the following structure:

[0008] The upper electrode is used to press the solder strip against the welding surface of the contact bracket to be welded and to weld the two together.

[0009] The lower electrode includes a contact support base, which is used for supporting and welding the contact support.

[0010] A contact support moving and positioning device includes a positioning fixture and a first drive cylinder for controlling the opening, closing and moving of the positioning fixture. The positioning fixture has a clamping cavity adapted to the shape of the contact support.

[0011] A welding strip moving and positioning device includes a welding strip moving device and a welding strip clamping device. The welding strip moving device includes a second driving cylinder, which is used to drive the welding strip clamping device to move (back and forth).

[0012] The welding strip clamping device includes a welding strip support track for supporting and orienting the welding strip, and also includes a clamping block and a clamping cylinder. The clamping block, driven by the clamping cylinder, clamps one end of the welding strip onto the welding strip support track.

[0013] Furthermore, the welding strip moving device also includes a welding strip clamping device support slide and a welding strip clamping device support slide cylinder; the welding strip clamping device support slide is driven by the welding strip clamping device support slide cylinder to move the welding strip clamping device up and down relative to the contact bracket support seat.

[0014] Secondly, the present invention uses the above-mentioned welding apparatus for welding, and the welding method includes:

[0015] Step 1, Contact support placement: Activate the contact support moving and positioning device. The first drive cylinder causes the positioning clamp to clamp the contact support. Then the positioning clamp moves the contact support to be welded to the contact support support seat on the lower electrode and positions it in the welding position.

[0016] Step 2: Placing the welding strip. Place the welding strip on the welding strip support track, with one end of the welding strip below the clamping block and a certain distance (about 0.1mm) from the clamping block. Leave the welding strip with the reserved contact length in front of the clamping block. Activate the clamping cylinder to make the clamping block clamp the welding strip. The second drive cylinder drives the welding strip clamping device to move one end of the welding strip, i.e. the position to be welded, to the surface of the contact bracket.

[0017] Step 3: Reserve the length of the welding strip. Drive the upper electrode downward by the motor. When the upper electrode presses down on the welding position of the welding strip and the contact support, the clamping block separates from the welding strip. The second drive cylinder drives the welding strip clamping device to move backward along the contact support base. At this time, because the upper electrode presses down on the welding position of the welding strip, the welding strip is exposed to the length of welding strip required for the second welding.

[0018] Step 4: Welding of the welding strip. The welding strip clamping device tightens the welding strip again, and the contact bracket moving and positioning device resets. According to the pre-set welding parameters, such as welding time, current and pressure, the upper and lower electrodes are energized for welding. The welding strip to be welded on the welding strip softens. When the physical tensile strength of the welding strip decreases to less than the pulling force of the welding strip moving device, the welding strip is broken (the pulling force generated during the reset process of the welding strip clamping device). Welding is completed.

[0019] Subsequently, the welding sheet clamping device is reset, the upper electrode is moved upward and reset, and the entire welding process is completed.

[0020] Steps one through four are repeated to achieve cyclic welding of the contact assembly solder pieces;

[0021] Preferably, step five is also included: the welding device includes at least two contact support moving and positioning devices. After a set of cycles is completed in steps one to four, one of the contact support moving and positioning devices moves a new contact support to the welding position, and the other contact support moving and positioning device moves the contact support with the welded sheet to the next station for contact welding.

[0022] By repeating steps one through five above, fully automated welding production can eventually be achieved.

[0023] The beneficial effects of this invention are as follows:

[0024] The welding process provided by this invention can automatically weld the welding pieces on the contact support without the need for manual placement of the contact support and manual welding. By using the relatively low melting point of the solder and the fact that the solder fills the welding surface of the contact and the support after melting and forms a multi-element alloy, the welding quality of the contact assembly is guaranteed, resulting in a high-quality joint strength. This invention can improve production efficiency, reduce production costs, and improve welding quality. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0026] Figure 1 This is a schematic diagram of the main structure of the welding device of the present invention;

[0027] Figure 2 This is a schematic diagram of a portion of the welding device of the present invention;

[0028] Figure 3 This is a schematic diagram showing the cooperation of the welding sheet moving positioning device, positioning fixture, and contact bracket support base in this invention;

[0029] Figure 4 This is a schematic diagram showing the cooperation between the welding strip moving and positioning device, the welding strip, and the contact bracket support in this invention;

[0030] Figure 5 This is a schematic diagram showing the cooperation between the positioning clamp and the contact bracket support in this invention;

[0031] Figure 6 for Figure 5 Enlarged view of point A in the middle;

[0032] In the figure, 1-lower electrode, 2-upper electrode, 3-positioning fixture, 4-welding strip, 41-welding strip support track, 5-clamping block, 6-clamping cylinder, 61-second drive cylinder, 62-welding strip moving device, 7-contact bracket (copper), 71-contact bracket support seat, 8-welding strip clamping device, 9-welding strip clamping device support slide, 91-welding strip clamping device support block, 10-welding strip clamping device support slide cylinder. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0035] The directional and positional terms used in this invention, such as "up," "down," "front," "back," "left," "right," "inner," "outer," "top," "bottom," and "side," are merely for reference to the accompanying drawings. Therefore, the directional and positional terms used are for illustrating and understanding this invention, and not for limiting the scope of protection of this invention.

[0036] Example 1

[0037] A welding process for a circuit breaker contact assembly, comprising welding a stationary contact assembly using a welding device, and the welding method including:

[0038] Step 1: Placement of the contact support. The stationary contact support to be welded is placed on the contact support base 71 using a vibrating plate or a robotic arm. The contact support base 71 can be shaped according to the shape and size of the support, so that the contact support 7 can move smoothly on the support base. The stationary contact support is made of copper alloy. The positioning clamp 3 is activated to clamp the stationary contact support, and the stationary contact support is moved to the welding position of the lower electrode 1 by the positioning clamp moving cylinder.

[0039] Step 2: Placing the solder strip. Place the solder strip 4 on the solder strip support track 41. The solder sheet clamping block 5 is in the loose state, with a distance of about 0.1mm between it and the solder strip 4. Place the solder strip 4 below the clamping block 5, and leave the solder strip with the contact length in front of the clamping block 5. Start the solder strip moving cylinder (second drive cylinder) 61, and send the solder strip to the position above the contact bracket 7 through the solder strip moving device 62.

[0040] Activate the support slide cylinder 10 of the welding strip clamping device to move the support slide 9 of the welding strip clamping device downward and the welding strip clamping device 8 to move, placing the welding strip 4 on the surface of the contact support; the welding strip is an Ag-based or other alloy material welding strip, such as Ag15CuP, AgCu28, etc.

[0041] Step 3: Reserve the length of the welding strip, start the drive cylinder of the upper electrode to drive the upper electrode 2 to press down. When the upper electrode 2 presses down on the welding strip and the copper contact bracket, start the welding strip moving cylinder (second drive cylinder) 61 to move the welding strip clamping block 5 and the welding strip moving device 62 back to reset. Since the upper electrode 2 is pressing down on one end of the welding strip at this time, the welding strip required for the second welding is pulled out. The size pulled out is adjusted according to the size of the contact point by adjusting the limit screw of the moving cylinder in the welding strip moving device 62 to meet the requirements of the second welding.

[0042] Step 4: Welding of the welding strip. The welding strip clamping cylinder 6 is activated again to drive the clamping block to clamp the welding strip 4. The welding strip clamping device support slide cylinder 10 is activated again, causing the welding strip clamping device support slide 9 to move the welding strip clamping device support block 91 upwards and reset, thereby moving the welding strip clamping device 8 upwards and resetting. The power supply of the resistance welding equipment is turned on according to the pre-set welding parameters (welding time, current, and pressure, etc.) to perform welding. The time interval between the upward resetting of the welding strip clamping device 8 and the start of the resistance welding equipment power supply is 0.1 seconds. During welding, the temperature rises, and the welding strip softens. When the physical tensile strength of the welding strip 4 drops below the cylinder tension, the welding strip 4 is broken, the welding strip clamping device 8 moves upwards and resets, and the upper electrode 2 moves upwards and resets, completing the entire welding process.

[0043] Step 5: Product movement. Reactivate the copper contact bracket moving fixture 3 to move the copper contact bracket with the welded pads to the next workstation for contact welding.

[0044] By repeating steps one through five above, fully automated welding production of stationary contact assemblies can be achieved.

[0045] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A welding device for welding a lug of a circuit breaker contact assembly, characterized by, The welding apparatus includes the following structure: Upper electrode (2), the upper electrode is used to press the solder strip (4) against the welding surface of the contact support (7) to be welded and to weld the two together; The lower electrode (1) includes a contact support base (71), which is used to support and weld the contact support (7); The contact support moving and positioning device includes a positioning clamp (3) and a first driving cylinder for controlling the opening, closing and moving of the positioning clamp (3). The positioning clamp (3) has a clamping cavity that is adapted to the shape of the contact support (7). The welding strip moving and positioning device includes a welding strip moving device (62) and a welding strip clamping device (8). The welding strip moving device (62) includes a second driving cylinder (61), which is used to drive the welding strip clamping device (8) to move. The welding strip clamping device (8) includes a welding strip support track (41) for supporting and orienting the welding strip (4), and also includes a pressing block (5) and a pressing cylinder (6). The pressing block (5) presses one end of the welding strip (4) onto the welding strip support track (41) under the drive of the pressing cylinder (6). The welding strip moving device (62) also includes a welding strip clamping device support slide (9) and a welding strip clamping device support slide cylinder (10); the welding strip clamping device support slide (9) drives the welding strip clamping device (8) to move up and down relative to the contact bracket support seat (71) under the drive of the welding strip clamping device support slide cylinder (10).

2. A welding process for a circuit breaker contact assembly tab, characterized by, Welding is performed using the welding apparatus described in claim 1, and the welding process includes: Step 1, Contact bracket placement: Start the contact bracket moving and positioning device. The first driving cylinder causes the positioning clamp (3) to clamp the contact bracket. Then the positioning clamp (3) moves the contact bracket (7) to be welded to the contact bracket support seat (71) on the lower electrode (1) and positions it in the welding position. Step 2: Placing the welding strip. Place the welding strip (4) on the welding strip support track (41) so that one end of the welding strip (4) is below the clamping block (5) and a certain distance away from the clamping block (5). Leave the welding strip (4) with the contact length in front of the clamping block (5). Start the clamping cylinder (6) to make the clamping block (5) clamp the welding strip (4). The second drive cylinder (61) drives the welding strip clamping device (8) to move one end of the welding strip (4) to the surface of the contact bracket. Step 3: Reserve the length of the welding strip. Drive the upper electrode (2) down by the motor. When the upper electrode (2) presses down on the welding position of the welding strip (4) and the contact bracket (7), the clamping block (5) separates from the welding strip (4). The second driving cylinder (61) drives the welding strip clamping device (8) to move backward along the contact bracket support seat (71). At this time, because the upper electrode (2) presses down on the welding position of the welding strip (4), the welding strip (4) is exposed to the length of the welding strip required for the second welding. Step 4: Welding of the welding sheet. The welding sheet clamping device (8) presses the welding sheet (4) again, and the contact bracket moving and positioning device is reset. According to the pre-set welding parameters, the upper and lower electrodes are energized for welding. The welding sheet to be welded on the welding sheet (4) softens. When the physical tensile strength of the welding sheet (4) drops to less than the pulling force of the welding sheet moving device (62), the welding sheet (4) is broken, and the welding is completed. The welding sheet clamping device (8) is reset, the upper electrode (2) is moved up and reset, and the entire welding process is completed.

3. The process of claim 2, wherein: Steps one through four are repeated to achieve cyclic welding of the contact assembly.

4. The welding process for the contact assembly weld plates of a circuit breaker according to claim 2, characterized in that: It also includes step five: the welding device includes at least two contact support moving and positioning devices. After a cycle of steps one to four is completed, one of the contact support moving and positioning devices moves a new contact support to the welding position, and the other contact support moving and positioning device moves the contact support with the welded sheet to the next station for contact welding.

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