A longitudinal magnetic contact structure of vacuum interrupter

Abstract

The invention discloses a longitudinal magnetic contact structure of a vacuum interrupter. The structure comprises a contact cup (1), the opening end of the contact cup (1) being connected to a contact sheet (2); oblique grooves (3) are distributed along the circumferential direction on the wall of the contact cup (1), the oblique grooves (3) penetrate the opening end to form a notch (4) on the end surface of the opening end, the notch (4) is tangent to the inner wall (5) of the contact cup (1), and the portion obtained by cutting between two adjacent oblique grooves (3) on the wall of the contact cup (1) constitutes a coil (8); longitudinal magnetic grooves (6) are distributed along the circumferential direction on the edge of the contact sheet (2), the longitudinal magnetic grooves (6) can be axially aligned with the notch (4), and one end of the longitudinal magnetic grooves (6) penetrates the edge of the contact sheet (2). The invention can achieve the purpose of low resistance while maintaining the short-circuit current breaking capacity unchanged, and is also conducive to miniaturized design.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum interrupter chambers, in particular to a longitudinal magnetic contact structure of a vacuum interrupter chamber. Background Art

[0002] The vacuum interrupter is the core component of the vacuum switch, responsible for controlling the arc current. The circuit breaking and closing are completed by the opening and closing movement of a pair of contacts with a magnetic field in the vacuum interrupter. In the existing small vacuum interrupter, with the opening end of the contact cup as the top, the contact cup coil of the cup-shaped longitudinal magnetic contact structure used for arc control includes a contact cup, and an inclined groove is arranged on the wall of the contact cup. The inclined groove rotates along the circumference of the contact cup toward the opening end of the contact cup and passes through the opening end. This structure has a disadvantage in use: in order to increase the current flow path, improve the longitudinal magnetic field strength, and enhance the short-circuit current breaking capacity of the vacuum interrupter, it is often necessary to increase the rotation angle of the inclined groove. α (Current α Usually between 90 and 103°), but as α The increase of the contact angle will make the groove cut deeper into the contact cup wall (i.e. the groove will be longer), and the coil resistance will increase accordingly, especially the resistance value of the coil root will be very large due to the small cross-sectional area. Since the short-circuit current breaking capacity and the rated working current are a pair of contradictions that are difficult to achieve, they can only be balanced. The vacuum interrupter with large breaking capacity often has a large resistance value, and the temperature rise is often too high during use. A large area of ​​pure copper heat sink is required for heat dissipation, which is too expensive. Otherwise, the reliability and stability of the switch operation will be affected due to overheating of the switch contact. In response to the temperature rise problem, when the user puts forward a low resistance requirement but must meet the required short-circuit current breaking capacity, the common practice is to increase the thickness of the coil outward, and thickening the coil outward will reduce the effective diameter and reduce the short-circuit current breaking capacity. In order to overcome this problem, the only way is to increase the contact cup coil, but this will increase the overall diameter of the vacuum interrupter, which is not conducive to the miniaturization design of the device. Summary of the invention

[0003] The purpose of the present invention is to provide a vacuum interrupter longitudinal magnetic contact structure. The present invention can achieve the purpose of low resistance while maintaining the short-circuit current breaking capacity unchanged, and is also conducive to miniaturization design.

[0004] The technical solution of the present invention is as follows: a longitudinal magnetic contact structure of a vacuum arc extinguishing chamber, comprising a contact cup, wherein the open end of the contact cup is connected to a contact piece; oblique grooves are distributed circumferentially on the wall of the contact cup, the oblique grooves pass through the open end to form a notch on the end surface of the open end, the notch is tangent to the inner wall of the contact cup, and the portion cut between two adjacent oblique grooves on the wall of the contact cup constitutes a coil; longitudinal magnetic grooves are distributed circumferentially on the edge of the contact piece, the longitudinal magnetic grooves can be axially aligned with the notch, and one end of the longitudinal magnetic groove passes through the edge of the contact piece.

[0005] In the aforementioned vacuum interrupter longitudinal magnetic contact structure, the other end of the longitudinal magnetic slot exceeds the diameter line perpendicular to the longitudinal magnetic slot.

[0006] In the aforementioned vacuum interrupter longitudinal magnetic contact structure, the other end of the longitudinal magnetic slot is connected with a straight slot, and the straight slot is perpendicular to the longitudinal magnetic slot.

[0007] In the aforementioned vacuum interrupter longitudinal magnetic contact structure, when the longitudinal magnetic grooves are axially aligned with the notches, there is at least one notch between two adjacent longitudinal magnetic grooves.

[0008] Beneficial effect: Compared with the prior art, the notch on the open end face of the inclined slot on the contact cup of the present invention is tangent to the inner cup wall of the contact cup, and the longitudinal magnetic slot arranged on the contact piece is aligned with the notch in the axial direction of the contact cup; through this structure, the longitudinal magnetic slot on the contact piece can form an obstacle to the current from the contact cup coil, preventing the current from flowing directly to the center of the contact piece. At this time, the current needs to bypass the longitudinal magnetic slot to flow to the center of the contact piece; therefore, through this structure, the current flow path can be effectively increased, the longitudinal magnetic field strength can be improved, and the breaking capacity of the vacuum interrupter can be enhanced. See Figure 1 and Figure 6 The arrows in the middle indicate the direction of the respective currents: Figure 1 When the current flows to the contact piece, it needs to bypass the longitudinal magnetic slot to flow to the center of the contact piece; Figure 6 When the current flows to the contact piece, it flows directly to the center of the contact piece; through this structure, the longitudinal magnetic groove forms an obstacle to the current.

[0009] contrast Figure 4 and Figure 8 It can be seen that the notch of the present invention is tangent to the inner cup wall, while the conventional notch is mainly along the radial direction of the contact cup.

[0010] The longitudinal magnetic field generated by the contact structure of the present invention is equivalent to the superposition of the longitudinal magnetic field generated by the coil between the inclined slots of the contact cup and the longitudinal magnetic field generated by the longitudinal magnetic slots on the contact sheet. The structure has the following characteristics:

[0011] First, the rotation angle of the inclined slot on the contact cup α Can reduce (the present invention can α From the traditional 90-103° to 80-85°), the angle of rotation of the contact cup due to the inclined groove α The reduced magnetic field is compensated by the magnetic field generated by the longitudinal magnetic slot on the contact piece; through this structure, while ensuring the short-circuit current breaking capacity remains unchanged, α The reduction in resistance reduces the contact cup coil.

[0012] Secondly, because the starting and ending points of the inclined slots are different from the conventional positions, the starting and ending points of the inclined slots have almost the same cross-section, eliminating the bottleneck problem of increased resistance caused by the small cross-section of the end point of the inclined slot in the commonly used contact structure. Specific principle: The slot is tangent to the inner cup wall of the contact cup, which makes the two adjacent inclined slots basically parallel. At the same time, the end point of the inclined slot is far away from the turning point of the elliptical cross-section, so that the cross-sectional area of ​​the coil along the current direction is basically equal, and the cross-sectional area of ​​the coil root near the turning point of the ellipse will not decrease, further reducing the coil resistance.

[0013] Without increasing the contact diameter, the reduction in coil resistance can effectively control the temperature rise of the contact during operation, which is beneficial to increase the rated current value of the vacuum interrupter while ensuring the breaking capacity of the vacuum interrupter. Figure 3 and Figure 7 :contrast Figure 3 and Figure 7 It can be seen from the position of the elliptical circle mark that the cross-sectional area of ​​the root of the coil of the present invention is increased, thereby reducing the root resistance.

[0014] Third, since the magnetic field of the contact structure is the superposition of the magnetic field generated by the contact cup coil and the magnetic field generated by the longitudinal magnetic slot of the contact piece, in the case of a smaller rated working current, the superimposed strong magnetic field can be used to reduce the contact diameter, and then reduce the diameter of the vacuum interrupter, thereby obtaining a miniaturized structure of a smaller vacuum interrupter.

[0015] In addition, the closer the traditional contact structure is to the edge of the contact, the weaker the magnetic field strength and arc control ability will be (see Fig.10 ). Therefore, in order to enhance the arc control capability, it is necessary to extend the edge of the contact outward, increase the diameter of the contact cup, and then increase the effective area of ​​the contact; and the outward extension of the edge of the contact will increase the diameter of the contact, and then increase the overall diameter of the vacuum arc chamber, which is not conducive to the miniaturization design of the device. When the coil current of the present invention flows to the contact piece, it needs to bypass the longitudinal magnetic slot to flow to the center of the contact piece. In this way, when the current flows along the edge of the contact piece, a magnetic field will be generated at the edge of the contact, thereby increasing the edge magnetic field of the contact (see Fig. 9 ), which improves the control ability of the contact edge arc, thereby enhancing the short-circuit current breaking capacity and its stability. The area where the edge magnetic field is generated is shown in Figure 5 The shadow part of Figure 5The middle arrow indicates the direction of current. The improvement of the arc control capability of the edge magnetic field is equivalent to the increase of the effective area of ​​the contact (especially the area of ​​the contact edge). Therefore, under the same arc control capability design requirements, the contact cup diameter of the present invention can be designed to be smaller, which is more conducive to the miniaturization of the device. In addition, due to the enhanced arc control capability, the present invention can also appropriately increase the thickness of the contact cup coil inward, further reducing the resistance value of the contact cup coil; this provides designers with more design margins, so that the design difficulty can be reduced. Compared with the conventional contact structure, the same is a cup-shaped longitudinal magnetic contact structure with a diameter of φ60. The resistance of the conventional contact structure is 13-18μΩ, and the resistance of the contact structure of the present invention is 7-9μΩ. It can be seen that the resistance reduction of the present invention is very significant.

[0016] The other end of the longitudinal magnetic groove of the present invention exceeds the diameter line perpendicular to the longitudinal magnetic groove; this structure can be more conducive to the longitudinal magnetic groove blocking the current on the coil and increase the current flow path.

[0017] The present invention has a straight slot perpendicular to the other end of the longitudinal magnetic slot connected thereto; the straight slot structure can effectively reduce the eddy current generated on the contact surface, enhance the short-circuit current breaking capacity and dielectric recovery speed, and is conducive to the breaking of asymmetric current.

[0018] The present invention has at least one slot between two adjacent longitudinal magnetic slots; through this structure, the distribution of the coil field strength along the circumference of the contact can be balanced according to actual needs, such as: when there is a slot between two adjacent longitudinal magnetic slots, the field strength of the corresponding coil is: strong → weak → strong, and the strong magnetic field on both sides can compensate for the weak magnetic field in the middle to a certain extent, thereby making the field strength distribution more balanced. The magnetic field distribution on the contact surface, if an even number of slots is used, obtains a strong, weak, strong and weak cyclic distribution of the magnetic field; if an odd number of slots is used, obtains a strong, medium, weak, strong, medium, weak cyclic distribution of the magnetic field. The above structure can ensure the improvement of the short-circuit current breaking current.

[0019] In summary, the present invention can achieve the purpose of low resistance while maintaining the short-circuit current breaking capacity unchanged, and is also conducive to miniaturized design. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the contact cup of the present invention;

[0022] Figure 3 is a front view of the contact cup of the present invention;

[0023] Figure 4 yes Figure 3 A top view of

[0024] Figure 5is a top view of the contact sheet of the present invention;

[0025] Figure 6 It is a schematic diagram of the structure of a traditional contact;

[0026] Figure 7 This is the front view of a traditional contact cup;

[0027] Figure 8 yes Figure 7 A top view of

[0028] Fig. 9 is a curve showing the change trend of the magnetic field strength from the center to the edge of the contact structure of the present invention; wherein d is the edge position of the magnetic field;

[0029] Fig.10 It is the trend curve of magnetic field intensity change from the center to the edge of the contact for the traditional contact structure; where d is the edge position of the magnetic field.

[0030] The markings in the attached drawings are: 1-contact cup, 2-contact piece, 3-oblique groove, 4-slot, 5-inner cup wall, 6-longitudinal magnetic groove, 7-straight groove, 8-coil, 9-diameter wire. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0032] Embodiment 1. A vacuum interrupter longitudinal magnetic contact structure, comprising: Figure 1-5 As shown, it includes a contact cup 1, and a contact sheet 2 is connected to the open end of the contact cup 1; inclined grooves 3 are distributed along the circumferential direction on the wall of the contact cup 1. In this embodiment, 8 inclined grooves 3 are taken as an example (see Figure 1 ), the inclined groove 3 passes through the opening end to form a notch 4 on the end surface of the opening end, and the notch 4 is tangent to the inner cup wall 5 of the contact cup 1 (see Figure 2 and Figure 4 ), the portion cut between two adjacent inclined grooves 3 on the wall of the contact cup 1 constitutes the coil 8 (see Figure 3 ); the contact piece 2 has longitudinal magnetic grooves 6 distributed along the circumferential direction on the edge, and the longitudinal magnetic grooves 6 can be axially aligned with the slot 4 (see Figure 1 ), one end of the longitudinal magnetic groove 6 passes through the edge of the contact piece 2.

[0033] The other end of the longitudinal magnetic groove 6 is beyond the diameter line 9 perpendicular to the longitudinal magnetic groove 6. Figure 5 .

[0034] The other end of the longitudinal magnetic groove 6 is connected to a straight groove 7, and the straight groove 7 is perpendicular to the longitudinal magnetic groove 6. Figure 5 .

[0035] When the longitudinal magnetic grooves 6 and the slots 4 are axially aligned, there is at least one slot 4 between two adjacent longitudinal magnetic grooves 6. Figure 1 In this embodiment, there is a slot 4 between two adjacent longitudinal magnetic slots 6.

Claims

1. A vacuum interrupter longitudinal magnetic contact structure, characterized in that: The invention comprises a contact cup (1), wherein the open end of the contact cup (1) is connected to a contact sheet (2); oblique grooves (3) are distributed along the circumferential direction on the wall of the contact cup (1), the oblique grooves (3) penetrate the open end and form a notch (4) on the end surface of the open end, the notch (4) is tangent to the inner wall (5) of the contact cup (1), and the portion cut between two adjacent oblique grooves (3) on the wall of the contact cup (1) constitutes a coil (8); longitudinal magnetic grooves (6) are distributed along the circumferential direction on the edge of the contact sheet (2), the longitudinal magnetic grooves (6) can be axially aligned with the notch (4), and one end of the longitudinal magnetic grooves (6) penetrates the edge of the contact sheet (2).

2. The vacuum interrupter longitudinal magnetic contact structure according to claim 1, characterized in that: The end of the other end of the longitudinal magnetic groove (6) exceeds a diameter line (9) perpendicular to the longitudinal magnetic groove (6).

3. The longitudinal magnetic contact structure of the vacuum interrupter according to claim 1 is characterized in that: The other end of the longitudinal magnetic groove (6) is connected to a straight groove (7), and the straight groove (7) is perpendicular to the longitudinal magnetic groove (6).

4. The longitudinal magnetic contact structure of the vacuum interrupter according to claim 1 is characterized in that: When the longitudinal magnetic grooves (6) are axially aligned with the slots (4), at least one slot (4) is spaced between two adjacent longitudinal magnetic grooves (6).

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