Contact structure of direct current contactor

Abstract

A direct current contactor contact structure comprises an insulating base and two static contacts, a push rod is connected below the insulating base, a contact hoop is installed above the insulating base, a moving contact is installed in the contact hoop, and a spring is installed between the lower surface of the moving contact and the bottom of an inner cavity of the contact hoop. The lower surfaces of the two static contacts vertically correspond to the two ends of the upper surface of the moving contact respectively. Two sides of the upper surface of the moving contact are respectively provided with a contact blade, the middle of the contact blade is provided with a strip-shaped notch, and the strip-shaped notch divides the contact blade into a left contact blade and a right contact blade; and a plurality of spiral grooves are uniformly formed in the lower surface of the static contact in a central symmetry manner. According to the utility model, the defects in the prior art are overcome, the breaking capacity of the contact can be effectively improved, and the thermal load generated by the arc root on the surface of the electrode is reduced, so that the problem that the surface of the contact is locally and seriously melted is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of DC contactors, and particularly relates to a contact structure of a DC contactor. Background Art

[0002] A DC contactor generally consists of an iron core, a coil, an armature, contact reeds, etc. As long as a certain voltage is applied across the coil ends, a certain current will flow through the coil, thereby generating an electromagnetic effect. Under the attraction of the electromagnetic force, the armature will overcome the pulling force of the return spring and be attracted to the iron core, driving the moving contact of the armature to engage with the static contact (normally open contact). When the coil is powered off, the electromagnetic attraction also disappears, and the armature will return to its original position under the reaction force of the spring, causing the moving contact to engage with the original static contact (normally closed contact). In this way, through engaging and releasing, the purpose of conducting and cutting off in the circuit is achieved.

[0003] When the contactor is disconnected, it is generally disconnected while being energized. At this time, since there is a voltage between the static contact and the moving contact piece, an arc will be generated at the moment when the moving contact piece and the static contact are separated. Therefore, in the traditional contact structure, the contact surface between the static contact and the moving contact and the inner part of the arc deflection and ablation on the circumferential surface of the static contact are easily ablated by the arc, resulting in difficult arc extinction, which directly restricts the electrical life and usage conditions of the DC contactor. Content of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the utility model provides a contact structure of a DC contactor, which overcomes the deficiencies of the prior art, is reasonably designed, can effectively improve the breaking ability of the contact, reduces the heat load generated by the arc root on the electrode surface, and thus prevents the problem of local severe melting on the contact surface.

[0005] To achieve the above purposes, the utility model is realized through the following technical solutions:

[0006] A contact structure of a DC contactor includes an insulating base and two static contacts. A push rod is connected below the insulating base, a contact clip is installed above the insulating base, a moving contact is installed inside the contact clip, a spring is installed between the lower surface of the moving contact and the bottom of the inner cavity of the contact clip, and the lower surfaces of the two static contacts are respectively vertically corresponding to the two ends of the upper surface of the moving contact;

[0007] Contact pieces are respectively arranged on both sides of the upper surface of the moving contact. A strip-shaped notch is opened in the middle of the contact piece, and the strip-shaped notch divides the contact piece into a left contact piece and a right contact piece; the lower surface of the static contact is symmetrically and evenly provided with a plurality of spiral grooves at the center.

[0008] Preferably, a contact positioning member is installed inside the contact clamp, an armature block is installed above the inner wall of the contact clamp, the moving contact is installed between the contact positioning member and the armature block, and the spring is installed between the lower surface of the contact positioning member and the bottom surface of the inner cavity of the insulating base.

[0009] Preferably, positioning protrusions are provided on both the front and rear side surfaces of the contact positioning member, and the positioning protrusions are respectively in contact with the front and rear side surfaces of the contact clamp.

[0010] The present utility model provides a contact structure of a DC contactor. It has the following beneficial effects: By symmetrically and uniformly arranging a plurality of spiral grooves on the lower surface of the static contact in a central symmetry manner, when the arc current generated at the moment of separation between the moving contact and the static contact flows through the spiral wire grooves, the magnetic force generated by the magnetic field component orthogonal to the arc drives the arc to rotate at a high speed along the spiral direction of the spiral wire grooves at the edge of the static contact, thus achieving the purpose that the surface of the static contact will not overheat and burn out, improving the breaking ability of the static contact, reducing the thermal load generated by the arc root on the electrode surface, thereby preventing local severe melting on the contact surface and prolonging the service life of the contact. In addition, the contact piece is divided into a left contact piece and a right contact piece through a strip-shaped notch, so as to increase the number of contact points between the static contact and the moving contact, achieve the purpose of reducing the electric repulsive force received by the moving contact, avoid the risk of the moving contact being bounced off to generate a strong arc and causing the contactor to adhere when the load passes through a large short-circuit current, and improve the safety performance and service life of the DC contactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the prior art.

[0012] Figure 1 Structure schematic diagram of the present utility model;

[0013] Figure 2 Cross-sectional structure schematic diagram of the present utility model;

[0014] Explanation of reference numerals in the drawings:

[0015] 1. Insulating base; 2. Static contact; 3. Contact clamp; 4. Moving contact; 5. Spring; 6. Contact piece; 7. Strip-shaped notch; 8. Spiral groove; 9. Contact positioning member; 10. Armature block; 11. Positioning protrusion. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] To make the objectives, technical solutions, and advantages of the present utility model clearer, the following will clearly and completely describe the technical solutions in the present utility model with reference to the accompanying drawings in the present utility model.

[0017] Example 1, as Figure 1-2As shown in the figure, a contact structure of a DC contactor includes an insulating base 1 and two static contacts 2. A push rod is connected below the insulating base 1, and a contact clip 3 is installed above the insulating base 1. A moving contact 4 is installed inside the contact clip 3. A spring 5 is installed between the lower surface of the moving contact 4 and the bottom of the inner cavity of the contact clip 3. The lower surfaces of the two static contacts 2 are respectively corresponding to the upper ends of the two sides of the upper surface of the moving contact 4 up and down.

[0018] On both sides of the upper surface of the moving contact 4, contact pieces 6 are respectively arranged. A strip-shaped notch 7 is opened in the middle of the contact piece 6. The strip-shaped notch 7 divides the contact piece 6 into a left contact piece and a right contact piece. The lower surface of the static contact 2 is symmetrically and evenly provided with a plurality of spiral grooves 8 at the center.

[0019] Working principle:

[0020] During use, by energizing the coil assembly of the DC contactor, the push rod is driven to move upward by the moving iron core, and then the entire insulating base 1 and the moving contact 4 are driven to move upward, so that the moving contact 4 contacts the static contact 2.

[0021] In this embodiment, by symmetrically and evenly arranging a plurality of spiral grooves 8 on the lower surface of the static contact 2 at the center, when the arc current generated at the moment when the moving contact 4 and the static contact 2 are separated flows through the spiral grooves 8, the magnetic force generated by the magnetic field component orthogonal to the arc drives the arc to rotate rapidly along the spiral direction of the spiral grooves 8 at the edge of the static contact 2. Therefore, the purpose that the surface of the static contact 2 is not overheated and damaged is achieved, the breaking capacity is improved, the thermal load generated by the arc root on the electrode surface is reduced, so as to prevent local severe melting of the contact surface and extend the service life of the contact. In addition, in this embodiment, the contact piece 6 is divided into a left contact piece and a right contact piece by the strip-shaped notch 7, so that the number of contact points between the static contact 2 and the moving contact 6 can be increased, the purpose of reducing the electric repulsive force received by the moving contact 4 is achieved, and the risk that the moving contact 4 is bounced off to generate a strong arc and cause the contactor to stick together when a large short-circuit current passes through the load is avoided, and the safety performance and service life of the DC contactor are improved.

[0022] Embodiment 3, as a further preferred solution of Embodiment 1, a contact positioning member 9 is installed inside the contact clip 3, an armature block 10 is installed above the inner wall of the contact clip 4, the moving contact 4 is installed between the contact positioning member 9 and the armature block 10, and the spring 5 is installed between the lower surface of the contact positioning member 9 and the bottom surface of the inner cavity of the insulating base 1. The installation and fixation effect of the moving contact 4 can be realized through the contact positioning member 9. In addition, during the working process, when a short-circuit current flows through the moving contact 4, the magnetic lines of force around the moving contact 4 gather at the contact positioning member 9, and a magnetic field is generated on the upper surface of the contact positioning member 9, generating a suction force on the armature block 10, so as to prevent the moving contact 4 from being bounced off.

[0023] Embodiment 4, as a further preferred solution of Embodiment 1, positioning bumps 11 are provided on both the front and rear side surfaces of the contact positioning member 9, and the positioning bumps 11 are respectively in contact with the front and rear side surfaces of the contact clamp 3. By having the positioning bumps 11 located on the front and rear side surfaces of the contact clamp 3 respectively for limiting, the problem that the contact positioning member 9 is skewed during movement can be effectively avoided.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A contact structure of a DC contactor, comprising an insulating base (1) and two static contacts (2). A push rod is connected below the insulating base (1). A contact clip (3) is installed above the insulating base (1). A moving contact (4) is installed inside the contact clip (3). A spring (5) is installed between the lower surface of the moving contact (4) and the bottom of the inner cavity of the contact clip (3). The lower surfaces of the two static contacts (2) are respectively vertically corresponding to the two ends of the upper surface of the moving contact (4). It is characterized in that: Contact pieces (6) are respectively arranged on both sides of the upper surface of the moving contact (4). A strip-shaped notch (7) is formed in the middle of the contact piece (6). The strip-shaped notch (7) divides the contact piece (6) into a left contact piece and a right contact piece. A plurality of spiral grooves (8) are evenly formed in a centrosymmetric manner on the lower surface of the static contact (2).

2. The contact structure of a DC contactor according to claim 1, wherein: A contact positioning member (9) is installed inside the contact clip (3). An armature block (10) is installed above the inner wall of the contact clip (4). The moving contact (4) is installed between the contact positioning member (9) and the armature block (10). The spring (5) is installed between the lower surface of the contact positioning member (9) and the bottom surface of the inner cavity of the insulating base (1).

3. The contact structure of a DC contactor according to claim 2, characterized in that: Positioning protrusions (11) are arranged on the front and rear side surfaces of the contact positioning member (9). The positioning protrusions (11) are respectively in contact with the front and rear side surfaces of the contact clip (3).

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