A copper-aluminum composite fuse contact assembly and a press riveting assembly method thereof

Abstract

The present application relates to the technical field of fuse, especially to a copper-aluminum composite fuse contact blade assembly, comprising a rivet jig mechanism for providing precise assembly space and applying controllable axial pressure, the interior of the rivet jig mechanism is provided with a separable contact blade mechanism, the contact blade mechanism comprises a positioning disc for providing axial limiting and circumferential anti-rotation, and the positioning disc is provided with a riveting block capable of forming permanent mechanical interlocking under pressure. The present application adopts a riveting assembly method to replace the traditional welding process, the expansion groove on the riveting end occurs radial plastic expansion under the action of axial pressure, which can make the riveting block and the positioning disc form permanent mechanical interlocking, completely avoiding the generation of welding defects such as virtual welding, blowhole and crack, compared with the traditional welding method, the present application does not need welding equipment and welding process control, the batch production qualified rate is high, and the product consistency and reliability are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of fuse technology, and in particular to a copper-aluminum composite fuse contact assembly and its press-fit assembly method. Background Technology

[0002] As an important component of fuses, the contact blade is used to connect the fusible element to the external terminal block. Its conductivity, connection reliability, and service life directly affect the overall performance of the fuse. Currently, fuse contact blades are generally made of pure aluminum or pure copper and are fixedly connected to the terminal block through welding. However, although the conductivity of pure aluminum contact blades can meet the basic requirements, they have poor high-temperature stability. After long-term current switching, they are prone to oxidation and deformation, which leads to increased contact resistance and decreased contact reliability. In addition, the welding process is prone to defects such as incomplete welds, porosity, and cracks, making it difficult to guarantee consistency during mass production.

[0003] To address the aforementioned issues, existing technologies have employed copper-aluminum composite materials to replace pure aluminum or pure copper. For instance, Chinese patent CN118782443A discloses a copper-aluminum composite contact knife, which achieves the composite of a copper layer and an aluminum substrate through metallurgical bonding. However, this solution still uses welding to connect the contact knife to the terminal block, failing to resolve welding defects. Furthermore, the assembly process of the copper-aluminum composite contact knife lacks targeted riveting assembly fixtures. During the riveting process, the riveted parts are prone to deflection, inaccurate positioning, and difficulty in removing the parts after riveting, severely affecting the riveting accuracy, consistency, and production efficiency of the product. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a copper-aluminum composite fuse contact knife assembly and its press-fit assembly method. This invention solves the technical problems of existing copper-aluminum composite contact knives still using welding for connection, which makes it difficult to eliminate welding defects, and the easy deflection, inaccurate positioning, and difficulty in removing the riveted parts during the press-fit assembly process. It has the advantages of high press-fit accuracy, good consistency, high production efficiency, reliable connection, and no need for welding.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a copper-aluminum composite fuse contact knife assembly, comprising a riveting fixture mechanism for providing precision assembly space and applying controllable axial pressure, wherein a separable contact knife mechanism is provided inside the riveting fixture mechanism, the contact knife mechanism including a positioning disc for providing axial limiting and circumferential anti-rotation, the positioning disc having a riveting block that can form a permanent mechanical interlock under pressure, the riveting fixture mechanism including a cylindrical base for providing a vertical assembly channel, the interior of the cylindrical base having a rectangular guide groove for guiding the riveting block to move vertically and limiting its circumferential rotation, the upper end of the cylindrical base having symmetrically arranged limiting protrusions for limiting the circumferential rotation of the positioning disc, and a top pressure cover for applying axial pressure being detachably installed on the top of the cylindrical base. Through the cooperation of the riveting fixture mechanism and the contact knife mechanism, the contact knife mechanism can be precisely guided, positioned and pressurized during the riveting process, ensuring the riveting accuracy and consistency of the riveting block and the positioning disc.

[0006] Preferably, the riveting block is provided with a riveting end, and the center of the top pressure cover is provided with a rectangular through groove for the riveting end to pass through. The circumferential limit of the riveting end by the rectangular through groove can further prevent the riveting end from deflecting during the riveting process and improve the riveting accuracy.

[0007] Preferably, a bottom circular block is detachably installed at the lower end of the cylindrical base. After riveting, if it is difficult to remove the contact knife mechanism from the upper end of the cylindrical base, the bottom circular block can be removed, and then the contact knife mechanism can be pushed out from the bottom.

[0008] Preferably, the positioning disc has a rectangular hole at its center, a limiting step is provided on the inner wall of the rectangular hole, and a riveting boss is provided at the root of the riveting end for forming an axial limiting fit with the limiting step. Through the fit between the riveting boss and the limiting step, the riveting end can be restricted from excessively penetrating into the rectangular hole.

[0009] Preferably, the inner wall of the rectangular hole is provided with a plurality of micro protrusions for elastic friction locking with the outer wall of the riveting end, and the positioning disc is symmetrically provided with positioning holes for sliding engagement with the limiting protrusion. Through the elastic embedding effect of the micro protrusions, it can resist loosening caused by high frequency micro vibration after riveting. Furthermore, through the cooperation between the positioning holes and the limiting protrusion, it can achieve foolproof positioning during assembly and ensure that the positioning disc is placed in the correct direction.

[0010] Preferably, the riveting end is provided with an expansion groove for radial plastic expansion under pressure. When the expansion groove is compressed and undergoes plastic expansion, it will cause the riveting block and the positioning disc to form a permanent mechanical interlock.

[0011] Preferably, the upper surface of the positioning disc has at least one annular groove for storing conductive anti-corrosion paste. The conductive anti-corrosion paste stored in the annular groove can fill the contact interface between the positioning disc and the top pressure cover during the riveting process, reduce the contact resistance and prevent oxidation corrosion of the interface.

[0012] By employing the above technical solution, the present invention provides a copper-aluminum composite fuse contact assembly, which has at least the following beneficial effects: 1. This invention uses a press-fit assembly method to replace the traditional welding process. The expansion groove on the riveting end undergoes radial plastic expansion under axial pressure, which enables the riveting block and the positioning disc to form a permanent mechanical interlock. This completely avoids welding defects such as incomplete welds, porosity, and cracks. Compared with the traditional welding method, this invention does not require welding equipment or welding process control, has a high batch production qualification rate, and significantly improves product consistency and reliability.

[0013] 2. The present invention has a rectangular guide groove inside the cylindrical base to guide the riveting block to move vertically and restrict its circumferential rotation. A rectangular through groove is opened on the top pressure cover to further limit the circumferential position of the riveting end, thus achieving double anti-deflection. Furthermore, the cooperation between the limiting protrusion and the positioning hole achieves foolproof positioning. Through the synergistic effect of the multi-level guiding and anti-deflection system, the problem of easy deflection and inaccurate positioning of riveted parts in existing press riveting assemblies is effectively solved, and the press riveting accuracy and consistency are greatly improved.

[0014] 3. The present invention provides a limiting step on the inner wall of the rectangular hole and a riveting boss at the root of the riveting end to cooperate with it. The two form an axial limiting fit, which can accurately limit the riveting end from excessively penetrating the rectangular hole and ensure that the expansion groove always expands at the predetermined position. This can effectively avoid locking failure caused by excessive or insufficient riveting. At the same time, it can play a pre-locking role before riveting, which can prevent parts from falling off and facilitate automated assembly.

[0015] 4. The present invention has multiple micro protrusions on the inner wall of the rectangular hole. After riveting, they will be embedded into the outer wall of the riveting end to form an elastic friction lock, which can effectively resist the loosening caused by high frequency micro vibration. At the same time, the annular groove on the upper surface of the positioning disc stores conductive anti-corrosion paste, which can fill the contact interface between the positioning disc and the top pressure cover, reduce the contact resistance and prevent oxidation corrosion. Through the synergistic effect of micro anti-loosening and interface protection structure, the service life of the product in harsh environments such as high vibration and high humidity is greatly improved.

[0016] 5. The positioning disc and riveting block of the present invention are both made of copper-aluminum composite material. The copper layer is located on the contact surface to ensure high conductivity, and the aluminum substrate achieves lightweighting. The contact resistance and material cost are reduced compared with pure aluminum contact blades. At the same time, the lower end of the cylindrical base is provided with a detachable bottom disc, which can push the product out from the bottom after riveting, effectively solving the problem of difficulty in removing the part after riveting. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a perspective view of the overall structure of the present invention; Figure 2 This is a schematic diagram of the cylindrical base structure in this invention; Figure 3 This is a schematic diagram of the riveting fixture mechanism in this invention; Figure 4 This is a schematic diagram of the top pressure cap structure in this invention; Figure 5 This is a schematic diagram of the contact knife mechanism in this invention; Figure 6 This is a schematic diagram of the positioning disc in this invention; Figure 7 This is a schematic diagram of the riveting block in this invention.

[0018] In the diagram: 1. Press-fit fixture mechanism; 101. Cylindrical base; 102. Bottom round block; 103. Rectangular guide groove; 104. Limiting protrusion; 105. Top pressure cap; 106. Rectangular through groove; 2. Contact knife mechanism; 201. Positioning round piece; 202. Rectangular hole; 203. Limiting step; 204. Micro protrusion; 205. Annular groove; 206. Positioning round hole; 207. Riveting block; 208. Riveting end; 209. Riveting boss; 210. Expansion groove. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 In the prior art, the riveting assembly process of the contact knife mechanism of copper-aluminum composite fuses usually relies on general riveting equipment, lacking targeted guiding, positioning, and part removal structures. This leads to the riveted parts being prone to deflection, inaccurate positioning, and difficulty in removing the parts after riveting during the riveting process, which seriously affects the riveting accuracy, consistency, and production efficiency of the product. In order to solve this technical defect in the prior art, this embodiment provides a copper-aluminum composite fuse contact knife assembly, including a riveting fixture mechanism 1 for providing precision assembly space and applying controllable axial pressure. The riveting fixture mechanism 1 has a separable contact knife mechanism 2 inside. Through the cooperation of the riveting fixture mechanism 1 and the contact knife mechanism 2, the contact knife mechanism 2 can be precisely guided, positioned, and pressurized during the riveting process, ensuring the riveting accuracy and consistency of the riveting block 207 and the positioning disc 201.

[0021] Specifically, the riveting fixture mechanism 1 includes a cylindrical base 101 for providing a vertical assembly channel. After riveting, if the contact knife mechanism 2 is difficult to remove from the upper end of the cylindrical base 101, the bottom round block 102 can be removed, and then the contact knife mechanism 2 can be pushed out from the bottom. The bottom round block 102 is detachably installed at the lower end of the cylindrical base 101. The interior of the cylindrical base 101 is provided with a rectangular guide groove 103 for guiding the riveting block 207 to move vertically and restricting its circumferential rotation. The upper end of the cylindrical base 101 is symmetrically provided with useful... The limiting protrusion 104 restricts the circumferential rotation of the positioning disc 201 and also serves as a foolproof positioning function to ensure that the positioning disc 201 is placed in the correct direction. A top pressure cover 105 for applying axial pressure is detachably installed on the top of the cylindrical base 101. A rectangular through groove 106 for the riveting end 208 to pass through is provided in the center of the top pressure cover 105. By limiting the circumferential movement of the riveting end 208 through the rectangular through groove 106, the riveting end 208 can be further prevented from deflecting during the riveting process, thereby improving the riveting accuracy.

[0022] This invention features a rectangular guide groove 103 inside the cylindrical base 101 to guide the riveting block 207 vertically and restrict its circumferential rotation. A rectangular through groove 106 on the top pressure cap 105 further limits the circumferential positioning of the riveting end 208, achieving double anti-deflection. Furthermore, the cooperation between the limiting protrusion 104 and the positioning hole 206 provides foolproof positioning. Through the synergistic effect of the multi-level guiding and anti-deflection system, the problem of easy deflection and inaccurate positioning of riveted parts in existing press-fit assemblies is effectively solved, significantly improving press-fit accuracy and consistency. Moreover, this invention uses a press-fit assembly method instead of traditional welding. The expansion groove 210 on the riveting end 208 undergoes radial plastic expansion under axial pressure, enabling a permanent mechanical interlock between the riveting block 207 and the positioning disc 201. This completely avoids welding defects such as incomplete welds, porosity, and cracks. Compared to traditional welding methods, this invention eliminates the need for welding equipment and process control, resulting in a high batch production pass rate and significantly improving product consistency and reliability.

[0023] Example 2 Based on Example 1, in order to achieve high-precision and high-reliability riveting and locking of the contact knife mechanism 2, prevent excessive penetration during the riveting process, and ensure that it can resist loosening caused by high-frequency vibration and galvanic corrosion between dissimilar metals such as copper and aluminum after riveting, such as Figure 1 as well as Figures 5-7As shown, this embodiment includes a contact knife mechanism 2. Specifically, the contact knife mechanism 2 includes a positioning disc 201 for providing axial limiting and circumferential anti-rotation. The positioning disc 201 is provided with a riveting block 207 that can form a permanent mechanical interlock under pressure. A rectangular hole 202 is opened in the center of the positioning disc 201. A limiting step 203 is provided on the inner wall of the rectangular hole 202. A riveting end 208 is provided on the riveting block 207. A riveting boss 209 is provided at the root of the riveting end 208 for forming an axial limiting engagement with the limiting step 203. Through the engagement of the riveting boss 209 and the limiting step 203, the riveting end 208 can be restricted from excessively penetrating the rectangular hole 202. A plurality of micro protrusions 204 are provided on the inner wall of the rectangular hole 202 for forming an elastic friction lock with the outer wall of the riveting end 208. Through the elastic embedding action of the micro protrusions 204, after the riveting is completed, the riveting end 208 can be locked in place. To resist loosening caused by high-frequency micro-vibrations after assembly, the upper surface of the positioning disc 201 is provided with at least one annular groove 205 for storing conductive anti-corrosion paste. The conductive anti-corrosion paste stored in the annular groove 205 can fill the contact interface between the positioning disc 201 and the top pressure cover 105 during the riveting process, reducing the contact resistance and preventing oxidation corrosion of the interface. The positioning disc 201 is symmetrically provided with positioning holes 206 for sliding engagement with the limiting protrusion 104. Through the engagement of the positioning holes 206 and the limiting protrusion 104, foolproof positioning can be achieved during assembly, ensuring that the positioning disc 201 is placed in the correct direction. The riveting end 208 is provided with an expansion groove 210 for radial plastic expansion under pressure. When the expansion groove 210 is plastically expanded under pressure, it will cause the riveting block 207 and the positioning disc 201 to form a permanent mechanical interlock.

[0024] As a further optimization of this embodiment, both the positioning disc 201 and the riveting block 207 are made of copper-aluminum composite material. Specifically, the copper-aluminum composite material includes a copper layer and an aluminum substrate, wherein the copper layer is located on the contact surface and is made of high-conductivity copper, and the aluminum substrate retains the lightweight advantage of aluminum. The copper and aluminum are metallurgically bonded through a hot rolling composite process.

[0025] The thickness of the copper layer is controlled between 0.8-1.2mm to ensure conductive contact area and oxidation resistance. The thickness of the aluminum substrate is graded and matched according to the rated current of the fuse: when the rated current is below 100A, the thickness of the aluminum substrate is 3-5mm; when the rated current is 100-400A, the thickness of the aluminum substrate is 5-8mm.

[0026] Through the application of the aforementioned copper-aluminum composite material, the contact resistance of the contact knife mechanism 2 can be reduced by more than 30% compared to that of a pure aluminum contact knife, and the temperature rise is ≤40K (compliant with GB / T 13539 standard). At the same time, the material cost can be reduced by about 25% compared to that of a pure copper contact knife.

[0027] In addition, before the riveting assembly, the contact surfaces of the positioning disc 201 and the riveting block 207 can be pickled and passivated to effectively remove the oxide film and further improve the contact reliability.

[0028] This invention features a limiting step 203 on the inner wall of the rectangular hole 202 and a matching riveting boss 209 at the root of the riveting end 208. These two elements form an axial limiting fit, precisely limiting the excessive penetration of the riveting end 208 into the rectangular hole 202. This ensures that the expansion groove 210 always expands at a predetermined position, effectively preventing locking failure caused by over- or under-riveting. Furthermore, it provides pre-locking before riveting, preventing parts from scattering and facilitating automated assembly. Additionally, the invention includes multiple micro-protrusions 204 on the inner wall of the rectangular hole 202. After riveting, these protrusions embed into the outer wall of the riveting end 208, forming an elastic friction lock that effectively resists loosening caused by high-frequency micro-vibrations. Meanwhile, the positioning disc 201... The annular groove 205 on the surface stores conductive anti-corrosion paste, which can fill the contact interface between the positioning disc 201 and the top pressure cover 105, thereby reducing contact resistance and preventing oxidation corrosion. Through the synergistic effect of micro-loosening prevention and interface protection structure, the service life of the product in harsh environments such as high vibration and high humidity is greatly improved. In addition, the positioning disc 201 and the riveting block 207 of the present invention are both made of copper-aluminum composite material. The copper layer is located on the contact surface to ensure high conductivity, and the aluminum substrate achieves lightweighting. The contact resistance and material cost are reduced compared with pure aluminum contact blades. At the same time, the lower end of the cylindrical base 101 is provided with a detachable bottom disc 102, which can push the product out from the bottom after riveting, effectively solving the problem of difficulty in removing the part after riveting.

[0029] Example 3 Based on Embodiments 1 and 2, this embodiment provides a riveting assembly method based on the above-described riveting fixture mechanism 1 and contact knife mechanism 2, including the following steps: Step 1: Place the riveting block 207 into the rectangular guide groove 103 of the cylindrical base 101; Step 2: Place the positioning disc 201 onto the riveting end 208 of the riveting block 207, and align the positioning hole 206 with the limiting protrusion 104. Step 3: Cover the top pressure cap 105 onto the upper end of the cylindrical base 101, so that the riveting end 208 passes through the rectangular through groove 106 of the top pressure cap 105; Step 4: Apply axial pressure to the top pressure cover 105 using an external pressurizing device to cause the expansion groove 210 to expand radially, thereby forming a permanent mechanical interlock between the riveting end 208 and the positioning disc 201. Step 5: Remove the bottom circular block 102 and push out the riveted contact knife mechanism 2 from the bottom of the cylindrical base 101.

[0030] This press-fit assembly method is simple to operate, highly precise, and consistent, making it suitable for mass production.

[0031] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0032] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A copper-aluminum composite fuse contact assembly, comprising a riveting fixture mechanism (1) for providing precision assembly space and applying controllable axial pressure, characterized in that: The riveting fixture mechanism (1) is equipped with a separable contact knife mechanism (2). The contact knife mechanism (2) includes a positioning disc (201) for providing axial limiting and circumferential anti-rotation, and the positioning disc (201) is provided with a riveting block (207) that can form a permanent mechanical interlock when pressed. The riveting fixture mechanism (1) includes a cylindrical base (101) for providing a vertical assembly channel. The cylindrical base (101) has a rectangular guide groove (103) inside for guiding the riveting block (207) to move in the vertical direction and restricting its circumferential rotation. The upper end of the cylindrical base (101) is symmetrically provided with limiting protrusions (104) for restricting the circumferential rotation of the positioning disc (201). A top pressure cap (105) for applying axial pressure is detachably installed on the top of the cylindrical base (101).

2. The copper-aluminum composite fuse contact assembly according to claim 1, characterized in that: The riveting block (207) is provided with a riveting end (208), and the top pressure cover (105) has a rectangular through groove (106) for the riveting end (208) to pass through.

3. The copper-aluminum composite fuse contact assembly according to claim 1, characterized in that: The lower end of the cylindrical base (101) is detachably fitted with a bottom circular block (102).

4. The copper-aluminum composite fuse contact assembly according to claim 1, characterized in that: The positioning disc (201) has a rectangular hole (202) at its center. A limiting step (203) is provided on the inner wall of the rectangular hole (202). The root of the riveting end (208) is provided with a riveting boss (209) for forming an axial limiting fit with the limiting step (203).

5. The copper-aluminum composite fuse contact assembly according to claim 4, characterized in that: The inner wall of the rectangular hole (202) is provided with a plurality of micro protrusions (204) for elastic friction locking with the outer wall of the riveting end (208), and the positioning disc (201) is symmetrically provided with positioning holes (206) for sliding engagement with the limiting protrusion (104).

6. The copper-aluminum composite fuse contact assembly according to claim 5, characterized in that: The riveting end (208) is provided with an expansion groove (210) for radial plastic expansion under pressure.

7. The copper-aluminum composite fuse contact assembly according to claim 1, characterized in that: The upper surface of the positioning disc (201) is provided with at least one annular groove (205) for storing conductive anti-corrosion paste.

8. A press-fit assembly method for the contact knife mechanism of a copper-aluminum composite fuse according to any one of claims 1 to 7, characterized in that, Includes the following steps:

1. Place the riveting block (207) into the rectangular guide groove (103) of the cylindrical base (101); 2. Place the positioning disc (201) on the riveting end (208) of the riveting block (207) and align the positioning hole (206) with the limiting protrusion (104).

3. Cover the top pressure cap (105) onto the upper end of the cylindrical base (101) so that the riveted end (208) passes through the rectangular through groove (106) of the top pressure cap (105). Fourth, apply axial pressure to the top pressure cover (105) through an external pressure device to cause the expansion groove (210) to expand radially, thereby forming a permanent mechanical interlock between the riveting end (208) and the positioning disc (201); 5. Remove the bottom round block (102) and push out the riveted contact knife mechanism (2) from the bottom of the cylindrical base (101).

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