A contact system for a molded case circuit breaker

Abstract

The utility model belongs to the field of circuit breaker, concretely relates to a contact system of moulded case circuit breaker, including base, static contact, pivot and movable contact, is equipped with the insulating partition that separates pivot area and static contact area in base, is equipped with the movement passageway that supplies movable contact swing to pass in insulating partition, still includes dynamic isolation mechanism, and dynamic isolation mechanism includes slide, transmission part, when movable contact and static contact are in closed state, slide is located in the position of avoiding, and movement passagewy keeps open, when movable contact and static contact separate to a preset position, transmission part is driven by movable contact, drives slide to slide from the position of avoiding to the position of plugging, to dynamic plugging movement passageway, realize pivot area and static contact area in the physical isolation of breaking process, can in movable, static contact breaking process, dynamic isolation mechanism can dynamically isolate pivot area and static contact area, effectively prevent the erosion of electric arc and metal vapor to pivot and other components.

Description

Technical Field

[0001] This utility model belongs to the field of circuit breaker technology, specifically relating to a contact system for a molded case circuit breaker. Background Technology

[0002] Molded case circuit breakers (MCCBs) are commonly used low-voltage protective electrical appliances used to automatically cut off current in the event of overload, short circuit, or other faults in a circuit, thereby protecting the safety of lines and equipment. The contact system is the core component of the circuit breaker, and its performance directly affects the circuit breaker's breaking capacity and electrical life.

[0003] When a circuit breaker interrupts a fault current, a high-temperature, high-voltage electric arc is generated between the moving and stationary contacts. If the arc cannot be quickly elongated, cooled, and extinguished, it may cause a phase-to-phase short circuit or burn damage to other internal components of the circuit breaker (such as the tripping mechanism, operating mechanism, and shaft), reducing the reliability and safety of the product. In existing technology, arc-extinguishing grids are usually installed near the contact system to cut and cool the arc. However, in the initial stage of the interruption process, the incandescent arc and metal vapor may still escape from the moving channel of the moving contact, eroding or affecting the structure of the shaft area, posing a safety hazard.

[0004] Therefore, how to effectively isolate the electric arc and metal vapor generated when the contacts break, and prevent them from damaging other critical components inside the circuit breaker, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a contact system for a molded case circuit breaker that can dynamically isolate the shaft area from the stationary contact area during the breaking process of the moving and stationary contacts, effectively preventing the erosion of components such as the shaft by electric arc and metal vapor, and improving the breaking reliability and electrical life of the circuit breaker.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A contact system for a molded case circuit breaker includes a base, a stationary contact fixed within the base, a rotating shaft rotatably disposed within the base, and a moving contact disposed on the rotating shaft. The base is provided with an insulating partition that isolates the rotating shaft area from the stationary contact area. The insulating partition has a movement channel through which the moving contact swings. The system also includes a dynamic isolation mechanism linked to the moving contact. The dynamic isolation mechanism includes a sliding plate slidably disposed on the insulating partition and a transmission component connecting the moving contact and the sliding plate. When the moving contact and stationary contact are in a closed state, the sliding plate is in a clearance position, and the movement channel remains open. When the moving contact and stationary contact separate to a preset position, the transmission component is driven by the moving contact, causing the sliding plate to slide from the clearance position to a blocking position, thereby dynamically blocking the movement channel and achieving physical isolation between the rotating shaft area and the stationary contact area during the breaking process.

[0007] In some embodiments, the transmission component is a connecting rod, one end of which is hinged to the slide plate, a positioning shaft is provided on the moving contact, and the other end of the connecting rod is rotatably connected to the positioning shaft. The swing of the moving contact is converted into the linear sliding of the slide plate through the connecting rod, so as to realize the blocking and opening of the movement channel by the slide plate.

[0008] In some embodiments, the skateboard is provided with a connecting shaft, and one end of the connecting rod is sleeved on the connecting shaft through a positioning hole.

[0009] In some embodiments, when the slide is in the blocking position, its blocking surface is in contact with the wall surface of the insulating partition, and the outline shape of the slide is configured to match the shape of the movement channel, so that the movement channel can be substantially closed when in the blocking position.

[0010] In some embodiments, two guide protrusions are provided in the base corresponding to both sides of the slide plate, and two guide grooves are formed between the two guide protrusions and the insulating partition. The two sides of the slide plate are respectively inserted into the two guide grooves.

[0011] In some embodiments, an insulating sleeve is wrapped around the moving contact between the rotating shaft and the moving contact.

[0012] In some embodiments, the insulating sleeve includes a first sleeve and a second sleeve, and a protective cavity is formed between the first sleeve and the second sleeve to enclose the moving contact. A knurled shaft is provided on the moving contact corresponding to the insulating sleeve, and the two ends of the knurled shaft are respectively engaged in the snap-fit ​​holes of the first sleeve and the second sleeve.

[0013] In some embodiments, the tail of the moving contact is provided with an arc-drawing angle above the moving contact, and the tail of the arc-drawing angle extends away from the moving contact.

[0014] In some embodiments, the moving contact has a circular arc convex surface that transitions between the moving contact and the arc-drawing angle.

[0015] The beneficial effects of this invention are as follows: By setting a dynamic isolation mechanism linked to the moving contact, the sliding plate automatically blocks the movement channel when the contact breaks to the preset position. This physically isolates the shaft area from the stationary contact area where the arc is generated during the critical breaking stage when the arc energy is high, effectively preventing the arc and metal vapor from escaping, protecting the shaft and surrounding mechanisms, and significantly improving the breaking reliability and electrical life of the product. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of this utility model.

[0017] Figure 1 This is a diagram showing the internal structure of a molded case circuit breaker according to an embodiment of the present invention. Figure 2 This is a perspective view of the base of an embodiment of the present utility model; Figure 3 This is a cross-sectional assembly view of the moving contact and insulating sheath in an embodiment of this utility model. Detailed Implementation

[0018] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0020] The directional and positional terms used in this utility model, such as up, down, front, back, left, right, inside, outside, top, bottom, side, etc., are only for reference to the accompanying drawings. Therefore, the directional and positional terms used are for the purpose of explaining and understanding this utility model, and not for limiting the scope of protection of this utility model.

[0021] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments: like Figure 1As shown, a contact system for a molded case circuit breaker includes a base 1, a stationary contact 2 fixed within the base 1, a rotating shaft 3 rotatably disposed within the base 1, and a moving contact 4 disposed on the rotating shaft 3. The base 1 has an insulating partition 11 that isolates the rotating shaft region 30 from the stationary contact region 20. The insulating partition 11 has a movement channel 111 through which the moving contact 4 swings. The system also includes a dynamic isolation mechanism 5 linked to the moving contact 4. The dynamic isolation mechanism 5 includes a component slidably disposed on the insulating partition 1. The sliding plate 51 on the 1 and a transmission component 52 connecting the moving contact 4 and the sliding plate 51 are configured such that when the moving contact 4 and the stationary contact 2 are in the closed state, the sliding plate 51 is in the clearance position, and the motion channel 111 remains open. When the moving contact 4 and the stationary contact 2 separate to a preset position, the transmission component 52 is driven by the moving contact 4, causing the sliding plate 51 to slide from the clearance position to the blocking position, thereby dynamically blocking the motion channel 111 and achieving physical isolation between the rotating shaft area 30 and the stationary contact area 20 during the separation process. The transmission component 52 is a connecting rod, with one end of the connecting rod hinged to the sliding plate 51. The moving contact 4 is provided with a positioning shaft 41, and the other end of the connecting rod is rotatably connected to the positioning shaft 41. The swing of the moving contact 4 is converted into the linear sliding of the sliding plate 51 through the connecting rod, thereby achieving the blocking and opening of the motion channel 111 by the sliding plate 51. By using the linkage mechanism, the rotational swing of the moving contact is accurately and reliably converted into the linear sliding of the sliding plate, resulting in high motion transmission efficiency and good mechanical characteristics. This structure is simple and reliable in design, easy to manufacture, low in cost, and has a stable connection, ensuring the long-term stability of the dynamic isolation mechanism. A connecting shaft 511 is provided on the slide plate 51, and one end of the connecting rod is fitted onto the connecting shaft 511 through a positioning hole 521. The connecting shaft of the slide plate and the positioning hole of the connecting rod cooperate to form a low-friction rotating pair, resulting in smooth transmission and minimal wear. It is also easy to install and maintain; this connection method has a simple structure, is easy to assemble, and is easy to install and maintain in confined base spaces. When the slide plate 51 is in the blocking position, its blocking surface is in contact with the wall of the insulating partition 11, and the contour shape of the slide plate 51 is constructed to match the shape of the movement channel 111, so that the movement channel 111 can be essentially closed when in the blocking position. The contact between the blocking surface of the slide plate and the wall of the insulating partition, and the matching shape with the movement channel, maximizes the sealing of the channel, prevents the formation of isolation gaps, significantly improves the reliability of physical isolation, and effectively prevents the diffusion of arc products. This ensures the insulation strength of the isolation area and reduces the risk of breakdown.

[0022] like Figure 1 and 2As shown, two guide protrusions 12 are provided on both sides of the slide plate 51 within the base 1. Two guide grooves 120 are formed between the two guide protrusions 12 and the insulating partition 11. The two sides of the slide plate 51 are respectively inserted into the two guide grooves 120. The guide grooves provide a precise trajectory for the linear movement of the slide plate, preventing the slide plate from deviating, getting stuck, or shaking during sliding, and ensuring that it can accurately reach and remain in the blocking position or avoidance position.

[0023] like Figure 1 and 3 As shown, an insulating sleeve 42 is wrapped around the moving contact 4 between the rotating shaft 3 and the moving contact 40. The insulating sleeve prevents electric arc from entering the rotating shaft area along the moving contact, protecting the rotating shaft and surrounding mechanisms, and significantly improving the product's breaking reliability and electrical life. The insulating sleeve 42 includes a first sleeve 421 and a second sleeve 422, forming a protective cavity wrapped around the moving contact 4 between the first sleeve 421 and the second sleeve 422. A knurled shaft 43 is provided on the moving contact 4 corresponding to the insulating sleeve 42, with both ends of the knurled shaft 43 respectively engaging in the engagement holes 423 of the first sleeve 421 and the second sleeve 422. The knurled shaft provides increased friction, and the engagement with the engagement holes achieves a tight interference fit or snap-fit ​​connection, ensuring that the insulating sleeve will not loosen or shift during the vibration of the moving contact during high-speed opening and closing. An arc-starting angle 44 is provided at the tail of the moving contact 4, above the moving contact 40. The tail of the arc-starting angle 44 extends away from the moving contact 40. The arc-starting angle guides the arc to quickly enter the arc-extinguishing chamber: during breaking, the arc-starting angle attracts the root of the arc to transfer upward from the moving contact, and uses its extension direction to guide and lengthen the arc, allowing it to enter the arc-extinguishing grid more quickly, thereby accelerating the cooling and extinguishing of the arc. This reduces contact erosion and promotes the arc to leave the main contact surface as soon as possible, helping to reduce electrical wear and erosion of the contact material. The moving contact 4 has a rounded convex surface 45 that transitions between the moving contact 40 and the arc-starting angle 44. The rounded convex surface provides a smooth, non-sharp-angled path for the transfer of the arc from the moving contact to the arc-starting angle, which is conducive to the smooth and rapid movement of the arc and prevents the arc from stagnating in a certain position, causing local overheating and burn-out.

[0024] This invention features a dynamic isolation mechanism linked to the moving contact. When the contact breaks to a preset position, a sliding plate automatically blocks the movement channel. This physically isolates the shaft area from the stationary contact area where the arc is generated during the critical breaking stage when the arc energy is high. This effectively prevents the arc and metal vapor from escaping, protecting the shaft and surrounding mechanisms, and significantly improving the product's breaking reliability and electrical life.

[0025] The above description is merely one embodiment of the present utility model and is not intended to limit the scope of protection of the present utility model; the scope of protection of the present utility model is defined by the claims in the claims, and all equivalent changes and modifications made in accordance with the utility model are within the scope of protection of the present utility model patent.

Claims

1. A contact system for a molded case circuit breaker, comprising a base, a stationary contact fixed within the base, a rotating shaft rotatably disposed within the base, and a moving contact disposed on the rotating shaft, characterized in that: The base is equipped with an insulating partition that isolates the rotating shaft area from the stationary contact area. The insulating partition has a movement channel through which the moving contact swings. It also includes a dynamic isolation mechanism linked to the moving contact. The dynamic isolation mechanism includes a sliding plate that is slidably mounted on the insulating partition and a transmission component that connects the moving contact and the sliding plate. When the moving contact and the stationary contact are in the closed state, the sliding plate is in the avoidance position and the movement channel remains open. When the moving contact and the stationary contact are separated to a preset position, the transmission component is driven by the moving contact to move the sliding plate from the avoidance position to the blocking position, thereby dynamically blocking the movement channel and achieving physical isolation between the rotating shaft area and the stationary contact area during the breaking process.

2. The contact system of the molded case circuit breaker according to claim 1, characterized in that: The transmission component is a connecting rod. One end of the connecting rod is hinged to the slide plate. A positioning shaft is provided on the moving contact. The other end of the connecting rod is rotatably connected to the positioning shaft. The swing of the moving contact is converted into the linear sliding of the slide plate through the connecting rod, so as to realize the blocking and opening of the movement channel by the slide plate.

3. The contact system of the molded case circuit breaker according to claim 2, characterized in that: The skateboard is provided with a connecting shaft, and one end of the connecting rod is sleeved on the connecting shaft through a positioning hole.

4. The contact system of the molded case circuit breaker according to claim 1, 2, or 3, characterized in that: When the slide is in the blocking position, its blocking surface fits against the wall of the insulating partition, and the outline shape of the slide is constructed to match the shape of the movement channel, so that the movement channel can be basically closed when in the blocking position.

5. The contact system of the molded case circuit breaker according to claim 4, characterized in that: The base has two guide protrusions on both sides of the slide plate, and the two guide protrusions and the insulating partition form two guide grooves, with the two sides of the slide plate respectively inserted into the two guide grooves.

6. The contact system of the molded case circuit breaker according to claim 1, characterized in that: An insulating sleeve is wrapped around the moving contact at the point between the rotating shaft and the moving contact.

7. The contact system of the molded case circuit breaker according to claim 6, characterized in that: The insulating sheath includes a first sheath and a second sheath, and a protective cavity is formed between the first sheath and the second sheath to wrap around the moving contact. A knurled shaft is provided on the moving contact corresponding to the insulating sheath, and the two ends of the knurled shaft are respectively engaged in the engagement holes of the first sheath and the second sheath.

8. The contact system of the molded case circuit breaker according to claim 1, characterized in that: The moving contact has an arc-drawing angle at the tail of the moving contact above the moving contact point, and the tail of the arc-drawing angle extends away from the moving contact point.

9. The contact system of the molded case circuit breaker according to claim 1, characterized in that: The moving contact has a rounded convex surface that transitions between the moving contact and the arc-starting angle.

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