Gradient material vacuum arc-extinguishing chamber longitudinal magnetic contact based on functional partition

Abstract

The invention relates to the technical field of vacuum arc extinguish chambers, and particularly discloses a gradient material vacuum arc extinguish chamber longitudinal magnetic contact based on functional partition, which comprises a contact cup and a contact blade, the contact cup is provided with an annular part and a main body part which are connected with each other, and one end, far away from the main body part, of the annular part is provided with a cup opening end; the annular part is provided with a plurality of spiral grooves arranged at intervals, the spiral grooves are used for forming a longitudinal magnetic field, and the spiral grooves extend towards the main body part along the cup opening end; the contact blade is provided with a surface layer, a middle layer and a transition layer which are stacked in sequence, and the transition layer is connected with the cup opening end; the contact cup and the contact blade are made of copper-chromium alloy, and the chromium content of the three-layer structure of the contact blade is different. According to the application, through the gradient material design of the adaptive contact function partition, collaborative optimization of surface layer ablation resistance-middle layer flow passing-structure deformation resistance of the contact is realized, and the performance shortages of the existing CuCr series contact are made up.

Description

Technical Field

[0001] This application relates to the field of vacuum interrupter technology, and in particular to longitudinal magnetic contacts for vacuum interrupters based on gradient materials with functional partitioning. Background Technology

[0002] Vacuum circuit breakers are core protection devices in power systems and are widely used in medium and high voltage fields. The material properties of their core component, the longitudinal magnetic contact, directly determine their breaking capacity and electrical life. Medium and low voltage vacuum interrupters mostly use CuBi, CuTeSe, and CuW alloys, while in high voltage fields of 10kV and above, due to the large breaking current and high arc energy, CuCr alloys have become the absolute mainstream. This system relies on the high conductivity of Cu and the high melting point of Cr to balance the core contradiction of "current carrying capacity - erosion resistance".

[0003] Among them, CuCr alloys with high Cr content exhibit significant advantages in resisting ablation: under high-voltage interruption conditions, the increase in Cr content can effectively disperse arc energy and reduce local ablation on the contact surface; the bonding characteristics between Cr particles and Cu matrix in its metallographic structure can suppress the flow and loss of molten Cu, making it an important choice for high-voltage vacuum interrupter contact materials.

[0004] Existing CuCr-based contacts all employ a single-component design across the entire contact area, without gradient optimization to meet the needs of different functional regions: While the surface layer of the contact plate, as the arc-generating zone, requires a high Cr content to resist arc erosion, the homogeneous design leads to insufficient Cu content in the current-carrying zone (intermediate layer), failing to balance the low-resistance current-carrying requirements; Simultaneously, the spiral groove wall of the contact cup, as the magnetic field generation zone, needs to balance structural deformation resistance and magnetic field continuity, but existing contact cup materials are pure Cu, lacking targeted strengthening phase modulation, making it difficult to adapt to the structural and functional requirements of the spiral groove; Furthermore, when the contact is assembled from multiple components (such as the contact plate and contact cup), abrupt changes in the composition of different materials at the connection point lead to weak interface performance, failing to achieve a smooth transition between composition and performance, affecting the overall structural stability and current conduction continuity.

[0005] In existing technologies, although a few solutions attempt to add reinforcing phases such as Mo and W to CuCr alloys to improve mechanical properties, they have significant limitations: on the one hand, the reinforcing phases are mostly uniformly mixed throughout the entire process, and the amount added is not adjusted according to the functional requirements of different regions of the contact (e.g., the spiral groove wall requires a higher content of reinforcing phase to resist deformation, while the flow passage area requires a smaller amount of added phase to reduce resistance); on the other hand, the interface bonding between the reinforcing phase and the CuCr matrix lacks gradient control, which easily leads to stress concentration in areas with high addition amounts, thereby reducing the overall mechanical properties of the material and failing to achieve functional synergy between the reinforcing phase and the matrix.

[0006] Regarding the performance optimization of vacuum interrupter contacts, relevant patents have proposed improvement schemes. For example, Chinese patent CN120108977A discloses a "double contact piece + contact support" structure, which achieves rapid interruption of large currents by dividing the arc through grooving and resisting ablation of the central contact piece; Chinese patent CN119833352A discloses a magnetic field contact with reinforcing ribs, which uses laser cladding integrated molding to improve structural strength and breaking capacity.

[0007] However, these technologies share common shortcomings: none employ gradient design, making them unable to adapt to the differentiated needs of contact functional zones. On the one hand, the homogeneity of material composition leads to performance contradictions—the surface arcing zone and the underlying current-passing zone share the same composition, making it difficult to balance ablation resistance and conductivity; on the other hand, heterogeneous components lack a compositional transition layer, and the interface is prone to loosening due to stress concentration; simultaneously, the functional areas lack targeted gradient reinforcement, resulting in insufficient impact resistance in mechanically weak areas and easy deformation in magnetic field generation areas, thus restricting overall performance improvement. Summary of the Invention

[0008] The technical problem to be solved by this application is: how to solve the problems of the contradiction between ablation resistance and conductivity caused by the use of uniform composition in the contacts in the prior art, the inability to accurately match the performance of functional areas, and the weakness of heterogeneous interfaces.

[0009] To address the aforementioned technical problems, this application provides a longitudinal magnetic contact for a gradient material vacuum interrupter based on functional partitioning, having a first direction, including: The contact cup, along the first direction, has a connected annular portion and a main body portion, and the annular portion has a cup mouth end away from the main body portion; the annular portion is provided with a plurality of spaced spiral grooves, the spiral grooves are used to form a longitudinal magnetic field, and the spiral grooves extend along the cup mouth end toward the main body portion; The contact piece has a surface layer, an intermediate layer and a transition layer stacked sequentially along the first direction, wherein the transition layer is connected to the cup mouth end; The contact cup and the contact plate are both copper-chromium alloys, and the chromium content of the surface layer is higher than that of the transition layer, the chromium content of the transition layer is higher than that of the intermediate layer, the chromium content of the annular portion is higher than that of the transition layer, and is also higher than that of the main body portion.

[0010] More preferably, the chromium content of the surface layer is 45wt% to 55wt%, the chromium content of the intermediate layer is 25wt% to 35wt%, and the chromium content of the transition layer is 35wt% to 45wt%.

[0011] More preferably, the chromium content of the surface layer is 50 wt%, the chromium content of the intermediate layer is 30 wt%, and the chromium content of the transition layer is 40 wt%.

[0012] More preferably, the intermediate layer contains molybdenum particles.

[0013] More preferably, along the first direction, the thickness of the intermediate layer is greater than the thickness of the surface layer, and the thickness of the intermediate layer is greater than the thickness of the transition layer.

[0014] More preferably, the chromium content of the annular portion is 45wt% to 55wt%, and the chromium content of the main body portion is 15wt% to 25wt%.

[0015] More preferably, the chromium content of the annular portion is 50 wt%, and the chromium content of the main body portion is 20 wt%.

[0016] More preferably, molybdenum particles are added to the annular portion.

[0017] More preferably, the spiral groove has a depth of 4-7 mm, a width L of 7-9 mm, and a spiral angle θ of 10-20°.

[0018] More preferably, the contact cup and the contact sheet are integrally formed.

[0019] Compared with existing technologies, the longitudinal magnetic contact of the vacuum interrupter based on functional partitioning proposed in this application has the following advantages: This application designs the contact plate as a three-layer gradient structure consisting of a surface layer, an intermediate layer, and a transition layer, with the transition layer connected to the cup end of the contact cup. The surface layer directly serves as the arc contact surface, forming an anti-ablation barrier to reduce the loss of Cu matrix under direct arc action, thus providing anti-ablation protection for the entire contact plate. The intermediate layer, as the intermediate current-passing layer, has a reduced chromium content, which increases the proportion of Cu matrix, thereby improving current-passing performance and achieving a balance between conductivity and structural strength. The chromium content of the transition layer is between that of the surface layer and the intermediate layer, effectively avoiding internal stress caused by sudden compositional changes, thereby improving the overall contact plate's performance. The bonding strength between the contact cups prevents delamination or cracking of the entire contact. The chromium content of the annular part is higher than that of the transition layer, which can resist the ablation caused by arc radiation heat, avoid deformation of the annular part due to ablation, ensure the continuity and stability of the longitudinal magnetic field distribution, and provide reliable support for arc confinement. In the closed state, after the current flows in, it passes through the main body, the annular part, the transition layer, and the intermediate layer in sequence, and finally makes contact with the opposite contact through the surface layer. In the entire conduction path, the high conductivity of the medium and low chromium region forms a low resistance channel, which can effectively control the temperature rise during current flow and meet the stability requirements of long-term current flow under high-voltage conditions. In the open state, the arc generated by the separation of the moving and stationary contacts first acts on the surface layer. The chromium particles in this region can split the arc into multiple diffuse arcs, avoiding local ablation of the contact caused by energy concentration. At the same time, the current flowing along the spiral groove of the annular part generates a longitudinal magnetic field, which can constrain the arc to always remain in a diffuse state and prevent excessive erosion caused by arc accumulation. When the current naturally crosses zero, the diffuse arc can be quickly extinguished. This application achieves synergistic optimization of the contact's "surface ablation resistance - intermediate layer flow passage - structural deformation resistance" through gradient material design adapted to the contact's functional partitions, thus making up for the performance shortcomings of existing CuCr-based contacts. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning as described in this application.

[0021] Figure label: 10. Contact cup; 101. Annular part; 102. Main body; 103. Cup mouth end; 104. Spiral groove; 105. Cup bottom end; 20. Contact plate; 201. Surface layer; 202. Intermediate layer; 203. Transition layer; L, width of the spiral groove; θ, spiral angle of the spiral groove; X, first direction. Detailed Implementation

[0022] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0023] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0026] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0027] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0028] like Figure 1 As shown, this application proposes a longitudinal magnetic contact of a gradient material vacuum interrupter based on functional partitioning, which has a first direction X. It should be noted that, for ease of explanation, the axial direction of the longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning is defined as the first direction X.

[0029] In a specific embodiment, the longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning includes a contact cup 10 and a contact piece 20; wherein the contact cup 10 and the contact piece 20 are connected along a first direction X.

[0030] In some embodiments, along the first direction X, the contact cup 10 has a connected annular portion 101 and a main body portion 102, and the end of the annular portion 101 away from the main body portion 102 has a cup mouth end 103; the annular portion 101 is provided with a plurality of spaced spiral grooves 104, the spiral grooves 104 are used to form a longitudinal magnetic field, and the spiral grooves 104 extend along the cup mouth end 103 toward the main body portion 102; the contact plate 20 along the first direction X has a surface layer 201, an intermediate layer 202 and a transition layer 203 stacked sequentially, and so on. The transition layer 203 is connected to the cup end 103. In order to achieve the synergistic optimization of the contact's "surface ablation resistance - intermediate layer flow passage - structural deformation resistance" and make up for the performance shortcomings of the existing CuCr-based contacts, the contact cup 10 and the contact plate 20 are limited to copper-chromium alloys. The chromium content of the surface layer 201 is higher than that of the transition layer 203, the chromium content of the transition layer 203 is higher than that of the intermediate layer 202, the chromium content of the annular part 101 is higher than that of the transition layer 203, and is also higher than that of the main body part 102.

[0031] Based on the above implementation, the contact piece 20 is designed as a three-layer gradient structure consisting of a surface layer 201, an intermediate layer 202, and a transition layer 203 stacked sequentially. The transition layer 203 is connected to the cup end 103 of the contact cup 10. The surface layer 201 directly serves as the arc action surface, forming an anti-ablation barrier to reduce the loss of Cu matrix under the direct action of the arc, thus providing anti-ablation protection for the entire contact piece 20. The intermediate layer 202 serves as an intermediate current-passing layer, and its reduced chromium content increases the proportion of Cu matrix, thereby improving current-passing performance and achieving a balance between conductivity and structural strength. The chromium content of the transition layer 203 is between that of the surface layer 201 and the intermediate layer 202. Between 0 and 2, it can effectively avoid internal stress caused by sudden changes in composition, thereby improving the bonding strength between the entire contact piece 20 and the contact cup 10, and preventing the entire contact from delamination or cracking; the chromium content of the annular part 101 is higher than that of the transition layer 203, which can resist the ablation caused by arc radiation heat, prevent the annular part 101 from deforming due to ablation, ensure the continuity and stability of the longitudinal magnetic field distribution, and provide reliable support for arc constraint; obviously, this application achieves the synergistic optimization of the contact's "surface ablation resistance - intermediate layer current flow - structural deformation resistance" through the gradient material design adapted to the contact's functional partitions, making up for the performance shortcomings of existing CuCr-based contacts.

[0032] In some embodiments, the chromium content of the surface layer 201 is 45wt% to 55wt%, the chromium content of the intermediate layer 202 is 25wt% to 35wt%, and the chromium content of the transition layer 203 is 35wt% to 45wt%.

[0033] For ease of explanation, the following embodiments and comparative examples are provided: Example 1: The chromium content of the surface layer 201 is 50 wt%, the chromium content of the intermediate layer 202 is 30 wt%, and the chromium content of the transition layer 203 is 40 wt%. Example 2: The chromium content of the surface layer 201 is 45 wt%, the chromium content of the intermediate layer 202 is 30 wt%, and the chromium content of the transition layer 203 is 40 wt%. Example 3: The chromium content of the surface layer 201 is 55 wt%, the chromium content of the intermediate layer 202 is 30 wt%, and the chromium content of the transition layer 203 is 40 wt%. Example 4: The chromium content of the surface layer 201 is 50 wt%, the chromium content of the intermediate layer 202 is 25 wt%, and the chromium content of the transition layer 203 is 45 wt%. Example 5: The chromium content of the surface layer 201 is 50 wt%, the chromium content of the intermediate layer 202 is 35 wt%, and the chromium content of the transition layer 203 is 35 wt%. Comparative Example 1: The chromium content of the surface layer 201 is 50 wt%, the chromium content of the intermediate layer 202 is 30 wt%, and the chromium content of the transition layer 203 is 20 wt%. Comparative Example 2: The chromium content of the surface layer 201, intermediate layer 202, and transition layer 203 is 40 wt%; Comparative Example 3: The chromium content of the surface layer 201, intermediate layer 202, and transition layer 203 is 50 wt%; Comparative Example 4: The chromium content of the surface layer 201 is 50 wt%, the chromium content of the intermediate layer 202 is 30 wt%, and the chromium content of the transition layer 203 is 30 wt%. The following experiments were conducted on Examples 1-5 and Comparative Examples 1-4: Table 1 Experimental Items and Performance Indicators The breaking performance and electrical life data of Examples 1-5 and Comparative Examples 1-4 are as follows: Table 2 Comparison of breaking performance and electrical life Table 2 shows the key conclusions: All embodiments of the present invention successfully passed short-circuit breaking, and their electrical lifetimes (26,500-30,000 cycles) were consistently and significantly higher than those of the conventional gradient comparative example 1 (22,000 cycles), and far superior to those of the single-gradient comparative examples 2 (15,000 cycles) and 3 (18,000 cycles). Furthermore, as shown in Table 2, the chromium content of the surface layer 201, intermediate layer 202, and transition layer 203 of this application fluctuated within a set range, and the minimum lifetime (Example 5) was also more than 20% better than that of Comparative Example 1.

[0034] The overall electrical performance of Examples 1-5 and Comparative Examples 1-4 is as follows: Table 3 Comparison of Comprehensive Electrical Performance (Temperature Rise and Weldability)

[0035] Table 3 shows the core conclusions: The embodiments of this invention significantly outperform conventional gradient comparative example 1 (250N) and single-gradient comparative example 2 (180N) in terms of weld resistance (opening force 110-130N), while exhibiting a much lower temperature rise (53-58K) than the homogeneous high-chromium material comparative example 3 (70K), achieving a perfect balance between arc resistance and electrical conductivity. The data from comparative example 4 clearly demonstrate that when the outer layer chromium content drops below 35wt%, weld resistance deteriorates significantly.

[0036] The experimental data in Tables 2 and 3 above fully demonstrate that the vacuum contacts manufactured using the non-monotonic gradient structure and its composition range defined in this application can synergistically optimize various key performance characteristics. Specifically, this manifests as: an overall improvement of electrical life of over 20%; a fundamental improvement in weld resistance (reducing the tripping force by approximately 50%); and a significantly lower temperature rise compared to high-chromium materials while maintaining excellent arc resistance. Importantly, this synergistic advantage is maintained even with adjustments within the stated composition range (45wt%–55wt% for the surface layer, 25wt%–35wt% for the intermediate layer, and 35wt%–45wt% for the transition layer) (see Examples 1–5). However, when the chromium content of the transition layer deviates from this range (as in Comparative Example 4), its overall performance, particularly weld resistance, will significantly degrade.

[0037] Based on the experimental data in Tables 2 and 3, this application preferably has a chromium content of 50 wt% for the surface layer 201, a chromium content of 30 wt% for the intermediate layer 202, and a chromium content of 40 wt% for the transition layer 203. That is, the material of the surface layer 201 is preferably CuCr50 alloy, the material of the intermediate layer 202 is preferably CuCr30 alloy, and the material of the transition layer 203 is preferably CuCr40 alloy.

[0038] In some embodiments, to further achieve a balance between contact conductivity and structural strength, molybdenum particles are added to the intermediate layer 202. By increasing the molybdenum particles, the chromium content can be reduced while the proportion of Cu matrix can be increased to ensure the current-carrying performance of the intermediate layer 202. At the same time, the molybdenum particles can compensate for the decrease in mechanical properties of the intermediate layer 202 caused by the reduction in chromium content, thereby achieving a balance between conductivity and structural strength.

[0039] In some embodiments, the chromium content of the annular portion 101 is 45wt% to 55wt%, and the chromium content of the main body portion 102 is 15wt% to 25wt%.

[0040] For ease of explanation, the contact piece 20 described in Example 1 is set as a fixed quantity (i.e., the chromium content of the surface layer is 50 wt%, the chromium content of the intermediate layer is 30 wt%, and the chromium content of the transition layer is 40 wt%), and the following examples and comparative examples are designed: Example 6: The chromium content of the annular portion 101 is 50 wt%, and the chromium content of the main body portion 102 is 20 wt%. Example 7: The chromium content of the annular portion 101 is 45 wt%, and the chromium content of the main body portion 102 is 25 wt%. Example 8: The chromium content of the annular portion 101 is 55 wt%, and the chromium content of the main body portion 102 is 15 wt%. Comparative Example 5: The entire contact cup is made of pure copper; Comparative Example 6: The chromium content of the annular portion 101 is 20 wt%, and the chromium content of the main body portion 102 is 20 wt%. The test data for interfacial bonding strength and thermomechanical stability of Examples 6-8 and Comparative Examples 5-6 are as follows: Table 4 Test data of interfacial bonding strength and thermomechanical stability As shown in Table 4, Examples 6-8 of this application all exhibited high and stable interfacial shear strength (195-205 MPa) and successfully passed thermal cycling and short-circuit impact tests without interface degradation. This proves that as long as the chromium content of the annular portion 101 of the contact cup 10 is maintained within the range of 45-55 wt%, it can form a strong and reliable metallurgical bond with the transition layer 203, achieving a smooth transition in performance.

[0041] Comparative Example 5 performed the worst in all interface-related tests, exhibiting low shear strength, cracking after thermal cycling, and a surge in resistance, revealing a failure mechanism where abrupt changes in composition between the contact cup and contact sheet lead to a weak interface. In Prior Artwork 2, the chromium content of the annular portion 101 is below 45%, resulting in intermediate performance, but it is still significantly inferior to Examples 6-8 of this application. This demonstrates the necessity for the annular portion 101 to use medium to high chromium to match the transition layer 203, and it is preferable that the chromium content of the annular portion 101 is greater than that of the transition layer 203.

[0042] The comprehensive electrical performance and heat dissipation test data of Examples 6-8 and Comparative Examples 5-6 are as follows: Table 5 Comprehensive Electrical Performance and Heat Dissipation Test Data Analysis of the data in Table 5 shows that Embodiments 6-8 of the present invention exhibit excellent and consistent current and heat conduction performance. The overall temperature rise is low (56.8-58.2K) and there is no localized overheating, which is attributed to the formation of a continuous gradient path with gradually increasing conductivity from the contact piece 20 to the main body 102.

[0043] Comparative Example 5 uses pure copper. Although pure copper itself has excellent conductivity, due to the interface bottleneck effect, its overall temperature rise is the highest, and significant hot spots appear, resulting in unstable dynamic resistance. Comparative Example 6 also suffers from insufficient performance due to the mismatch in chromium content in the annular portion.

[0044] The experimental data in Tables 4 and 5 above fully demonstrate that, in Examples 6-8 designed using the present invention, the transition layer 203 (Cr 40wt%) and the annular portion 101 (Cr 45-55wt%) form a reliable interface with high bonding strength and excellent thermomechanical stability due to their similar composition and physical properties (such as hardness and coefficient of thermal expansion). Simultaneously, a continuous electrical and thermal conductivity gradient is formed from the contact piece 20 to the main body 102 (Cr 15-25wt%), ensuring efficient and uniform conduction of current and heat flow, resulting in low overall temperature rise and no localized overheating.

[0045] Based on the experimental data in Tables 4 and 5, this application preferably has a chromium content of 50 wt% for the annular portion 101 and a chromium content of 20 wt% for the main body portion 102, that is, the material of the annular portion 101 is CuCr50 alloy and the material of the main body portion 102 is CuCr20 alloy.

[0046] In some embodiments, molybdenum particles are added to the annular portion 101. The molybdenum particles can further enhance the structural deformation resistance of the annular portion 101, ensure the stability of the slot shape during the breaking process, thereby ensuring the continuity and stability of the longitudinal magnetic field distribution and providing reliable support for arc confinement. Furthermore, molybdenum particles are added to both the intermediate layer 202 and the annular portion 101, which can resist the mechanical impact caused by the opening operation, ensure that the contacts remain structurally stable under high-frequency opening and closing cycles, avoid deformation or performance degradation caused by stress accumulation, and ensure the long-term reliable operation of the vacuum interrupter.

[0047] In some embodiments, the outer diameter of the annular portion 101 is preferably 60 mm, the inner diameter is preferably 45 mm, and the diameter of the contact piece 20 is equal to the outer diameter of the annular portion 101, so that the groove opening of the spiral groove 104 can be precisely aligned with the edge of the contact piece 20, ensuring that the current can directly enter the spiral groove 104 after flowing out of the contact piece 20, guiding the current to form a circumferential component, thereby generating a uniform longitudinal magnetic field and avoiding arc accumulation caused by uneven magnetic field distribution.

[0048] In some embodiments, the groove depth of the spiral groove 104 is 4-7 mm. The groove depth determines the effective height of the conductor perpendicular to the current direction. A groove depth of 4-7 mm ensures that the spiral groove 104 has a sufficient conductor cross-section, preventing overheating when carrying large short-circuit currents, and generating a magnetic field strength that meets the breaking requirements, thereby ensuring sufficient current path and magnetic field strength. With the wall thickness of the annular portion 101 ((60-45) / 2 = 7.5 mm), a groove depth of 4-7 mm ensures that 0.5-3.5 mm of solid material remains at the bottom of the groove, guaranteeing the structural integrity and mechanical strength of the annular portion when subjected to huge electrodynamic repulsion and thermal stress, and preventing cracking or deformation. In some preferred embodiments, the groove depth of the spiral groove 104 is preferably 6 mm.

[0049] In some embodiments, the width L of the spiral groove 104 is 7-9 mm. A wider groove (7-9 mm) means that the conductive bridges between the grooves are relatively narrow. This helps to force the current to flow more concentratedly along the spiral path, enhancing the magnetic field generation efficiency and improving the stability of the generated longitudinal magnetic field; at the same time, it can provide a better heat dissipation path, because heat is more easily dissipated to the surrounding space through the wider groove. If the width of the spiral groove 104 is too narrow (e.g., <7 mm), it not only increases the processing difficulty but also easily leads to stress concentration, making it impossible to guarantee the structural stability of the contact cup 10. In some preferred embodiments, the width L of the spiral groove 104 is preferably 8 mm.

[0050] In some embodiments, the helix angle θ of the spiral groove 104 is 10-20°. Within this angle range, a sufficiently strong longitudinal magnetic field component can be generated to effectively drive the arc rotation, while avoiding an excessively large transverse magnetic field component (a transverse magnetic field would cause the arc to contract, which is not conducive to arc extinguishing), ensuring that a stable longitudinal magnetic field is generated when the current flows through it. If the helix angle θ is too small, the spiral groove 104 is close to a straight groove, and the longitudinal magnetic field is weak. If the helix angle θ is too large, the current path is too long, the resistance increases, the current carrying capacity decreases, and the magnetic field may be too strong, leading to a prolonged arcing time. In some preferred embodiments, the helix angle θ of the spiral groove 104 is preferably 15°.

[0051] In some embodiments, the contact cup 10 and the contact piece 20 are integrally formed to ensure that the transition layer 203 and the cup mouth 103 are completely fitted together, ensuring that the two are in contact without gaps and avoiding the generation of local resistance during current conduction.

[0052] In some embodiments, along the first direction X, the end of the contact cup 10 away from the contact piece 20 has a cup bottom end 105, and the spiral groove 104 is spaced apart from the cup bottom end 105. Preferably, the spiral groove 104 on the contact cup 10 weakens the local strength. Sufficient base material thickness ensures that after the groove is machined, there is still enough material at the bottom of the groove, avoiding cracks at the groove root due to insufficient strength, especially when subjected to frequent mechanical impacts. Therefore, in this embodiment, the thickness of the contact cup 10 is 18-22mm. A contact cup 10 with a thickness of 18-22mm can have sufficient rigidity to prevent irreversible plastic deformation or structural instability of the contact, ensuring accurate alignment of the moving and stationary contacts and long-term mechanical reliability. In some preferred embodiments, the thickness of the contact cup 10 is preferably 20mm.

[0053] Along the first direction X, the arc ablation depth is typically limited in a single interruption. An excessively thick contact piece 20 (e.g., >8mm) does not provide additional electrical life benefits but instead significantly increases the cost of expensive materials. Under the influence of the longitudinal magnetic field, the arc energy is diffused across the entire surface of the contact piece 20. A thickness of 3-5mm provides sufficient volume to absorb and melt the surface material while ensuring rapid downward heat conduction to the high-heat-capacity contact cup 10, preventing heat accumulation that could lead to overall overheating and melting of the contact piece. Therefore, in this application, the thickness of the contact piece 20 is 3-5mm. Thinner contact pieces are easier to precisely control in terms of composition through processes such as powder metallurgy. When integrally formed with the contact cup, a thickness of 3-5mm helps reduce welding stress caused by the difference in thermal expansion coefficients, improving the reliability of the interface bonding. In some preferred embodiments, the thickness of the contact piece 20 is preferably 4mm.

[0054] In some embodiments, the intermediate layer 202 has the lowest chromium content, low hardness, and good plasticity. Its main function is to absorb and buffer the enormous thermal stress generated during arc heating and cooling due to the difference in thermal expansion coefficients between the inner and outer layers. The surface layer 201 and the transition layer 203 directly bear the most severe arc plasma impact and require the highest ablation resistance. Therefore, along the first direction X, the thickness of the intermediate layer 202 is defined as greater than the thickness of the surface layer 201, and the thickness of the intermediate layer 202 is greater than the thickness of the transition layer 203. Further, the thickness of the intermediate layer 202 is preferably 2 mm. A thickness of 2 mm provides sufficient plastic deformation volume, effectively dispersing stress over a wider area, fundamentally preventing interface peeling or microcracks caused by stress concentration between the high-hardness materials of the surface layer 201 and the transition layer 203. Further, the thickness of both the surface layer 201 and the transition layer 203 is preferably 1 mm. Arc ablation is a surface process, and a thickness of 1 mm provides sufficient material margin for ablation resistance, ensuring that the contact is not burned through throughout its entire electrical life. Meanwhile, since the surface layer 201 and the transition layer 203 have a high chromium content, they are more expensive and have slightly lower conductivity. Therefore, a thickness of 1 mm achieves the best balance between cost and performance while meeting functional requirements, avoiding unnecessary waste.

[0055] In summary, the longitudinal magnetic contact of the vacuum interrupter based on functional partitioning proposed in this application designs the contact piece 20 as a three-layer gradient structure consisting of a surface layer 201, an intermediate layer 202, and a transition layer 203 stacked sequentially. The transition layer 203 is connected to the cup end 103 of the contact cup 10. The surface layer 201 directly serves as the arc action surface, forming an anti-ablation barrier to reduce the loss of Cu matrix under the direct action of the arc, thus providing anti-ablation protection for the entire contact piece 20. The intermediate layer 202 serves as the intermediate current-passing layer, and its reduced chromium content increases the proportion of Cu matrix, thereby improving current-passing performance and achieving a balance between conductivity and structural strength. The chromium content of the transition layer 203 is between that of the surface layer 201 and the intermediate layer 202, effectively avoiding compositional abrupt changes. The internal stress induced by the arc increases the bonding strength between the entire contact piece 20 and the contact cup 10, preventing the entire contact from delamination or cracking. The chromium content of the annular portion 101 is higher than that of the transition layer 203, which can resist the ablation caused by arc radiation heat, prevent the annular portion 101 from deforming due to ablation, ensure the continuity and stability of the longitudinal magnetic field distribution, and provide reliable support for arc constraint. In the closed state, after the current flows in, it passes through the main body 102, the annular portion 101, the transition layer 203, and the intermediate layer 202 in sequence, and finally makes contact with the opposite contact through the surface layer 201. In the entire conduction path, the high conductivity of the medium and low chromium region forms a low resistance channel, which can effectively control the temperature rise during current flow and meet the stability requirements of long-term current flow under high voltage conditions. In the open / closed state, the electric arc generated by the separation of the moving and stationary contacts first acts on the surface layer 201. The chromium particles in this area can split the arc into multiple diffused arcs, avoiding localized contact ablation caused by energy concentration. At the same time, when the current flows along the spiral groove 104 of the annular portion 101, a longitudinal magnetic field is generated. This magnetic field can constrain the arc to always remain in a diffused state, preventing excessive erosion caused by arc accumulation. When the current naturally crosses zero, the diffused arc can be quickly extinguished. The molybdenum particles added to the intermediate layer 202 and the annular portion 101 can resist the mechanical impact brought about by the opening operation, ensuring that the contacts remain structurally stable under high-frequency opening and closing cycles, avoiding deformation or performance degradation caused by stress accumulation, and ensuring long-term reliable operation of the vacuum interrupter. This application achieves synergistic optimization of the contact's "surface ablation resistance - intermediate layer current flow - structural deformation resistance" through gradient material design adapted to the contact's functional zoning, making up for the performance shortcomings of existing CuCr-based contacts.

[0056] In another embodiment, this application also proposes a vacuum interrupter, which includes the longitudinal magnetic contact of the vacuum interrupter based on functional partitioning of the above embodiments. Since the vacuum interrupter adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0057] In another embodiment, this application also proposes a vacuum circuit breaker, which includes the vacuum interrupter described in the above embodiments. Since the vacuum circuit breaker adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0058] The above description is merely a preferred embodiment of this application. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application. The basic principles, main features, and advantages of this application have been shown and described above. For those skilled in the art, it is obvious that this application is not limited to the details of the above preferred embodiments. The embodiments should be considered exemplary and non-limiting. The scope of this application is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included within this application.

[0059] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in the embodiments can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A gradient material vacuum interrupter longitudinal magnetic contact based on functional partitioning, having a first direction, characterized in that, include: The contact cup, along the first direction, has a connected annular portion and a main body portion, and the annular portion has a cup mouth end away from the main body portion; the annular portion is provided with a plurality of spaced spiral grooves, the spiral grooves are used to form a longitudinal magnetic field, and the spiral grooves extend along the cup mouth end toward the main body portion; The contact piece has a surface layer, an intermediate layer and a transition layer stacked sequentially along the first direction, wherein the transition layer is connected to the cup mouth end; The contact cup and the contact plate are both copper-chromium alloys, and the chromium content of the surface layer is higher than that of the transition layer, the chromium content of the transition layer is higher than that of the intermediate layer, the chromium content of the annular portion is higher than that of the transition layer, and is also higher than that of the main body portion.

2. The longitudinal magnetic contact of the vacuum interrupter based on functional partitioning of gradient materials according to claim 1, characterized in that, The chromium content of the surface layer is 45wt% to 55wt%, the chromium content of the intermediate layer is 25wt% to 35wt%, and the chromium content of the transition layer is 35wt% to 45wt%.

3. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 2, characterized in that, The chromium content of the surface layer is 50 wt%, the chromium content of the intermediate layer is 30 wt%, and the chromium content of the transition layer is 40 wt%.

4. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 3, characterized in that, The intermediate layer contains molybdenum particles.

5. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 1, characterized in that, Along the first direction, the thickness of the intermediate layer is greater than the thickness of the surface layer, and the thickness of the intermediate layer is greater than the thickness of the transition layer.

6. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 1, characterized in that, The chromium content of the annular portion is 45wt% to 55wt%, and the chromium content of the main body portion is 15wt% to 25wt%.

7. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 6, characterized in that, The chromium content of the annular portion is 50 wt%, and the chromium content of the main body portion is 20 wt%.

8. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 7, characterized in that, The annular portion contains molybdenum particles.

9. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 1, characterized in that, The spiral groove has a depth of 4-7 mm, a width L of 7-9 mm, and a spiral angle θ of 10-20°.

10. The longitudinal magnetic contact of the gradient material vacuum interrupter based on functional partitioning according to claim 1, characterized in that, The contact cup and the contact sheet are integrally formed.

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