A movable contact mechanism of a molded case circuit breaker

Abstract

The utility model discloses a movable contact mechanism of moulded case circuit breaker, including contact support, main contact, arc contact and return spring. The arc contact top is equipped with the first contact inclined plane that is inclined to the up, and the inclined plane is equipped with the movable contact point with arc contact surface, the cooperation of arc contact and contact support pivot hole is long ellipse structure, and arc contact can slide along the long ellipse length direction under the action of return spring to compensate the abrasion displacement. When closing, so as to reach the effect that arc contact contacts static contactor earlier than main contact, and arc contact breaks off later than main contact when opening, realize the mechanism action that arc contact closes first and opens later. The arc extinguishing effect of the moulded case circuit breaker of the application is improved significantly, the first contact inclined plane cooperates with arc extinguishing chamber second contact inclined plane, through the sliding contact of movable contact point arc contact surface, the arc is forced to guide to the vicinity of arc extinguishing grid, and arc extinguishing is carried out in the first time, and the arc burning time is shortened, has the automatic abrasion compensation function, and long ellipse pivot hole cooperates with return spring, and arc contact is automatically forwardly displaced after abrasion, guarantees the contact pressure, prolongs the service life, and the product performance is stable and reliable, keeps good arc extinguishing and contact performance in the whole life cycle, and reduces the maintenance cost.

Description

Technical Field

[0001] This utility model relates to the technical field of molded case circuit breakers, specifically to a moving contact mechanism for a molded case circuit breaker. Background Technology

[0002] Molded case circuit breakers (MCCBs) require tripping to interrupt fault currents when an overload or short circuit occurs. During tripping, a high-temperature electric arc is generated momentarily when the moving and stationary contacts separate. To quickly extinguish the arc, the circuit breaker typically contains an arc-extinguishing chamber with several arc-extinguishing grids arranged inside. When the arc is introduced into the arc-extinguishing grids, it is broken into several short arcs, thus extinguishing it rapidly.

[0003] In existing molded case circuit breakers, the moving contact mechanism typically includes a contact support, main contacts, and an arcing contact. During tripping, the main contacts open first, the arc transfers to the arcing contact, and then the arcing contact engages with the arc-extinguishing chamber to guide the arc into the arc-extinguishing grid. However, in traditional structural designs, the lower end face of the arcing contact is often flat. When the arcing contact rotates downwards to contact the bottom surface of the arc-extinguishing chamber, because the arc-extinguishing grid is usually located on the side far from the arc-extinguishing chamber opening (i.e., far from the breaking point of the moving and stationary contacts), the flat arcing contact results in the initial position of the arc generated during tripping being far from the arc-extinguishing grid.

[0004] An electric arc needs its own magnetic field or gas flow to enter the arc-extinguishing grid. Excessive distance will prolong the time it takes for the arc to enter the grid, and may even prevent the arc from entering the grid plates altogether, resulting in poor arc extinguishing and a longer arcing time. Prolonged arcing not only erodes the contact surface but also generates a large amount of heat, severely impacting the electrical life and breaking reliability of the circuit breaker.

[0005] Furthermore, during long-term use, the part of the arc contact that contacts the arc chamber will wear down due to frequent friction and arc erosion. In existing structures, the arc contact typically engages with the contact support shaft via a circular rotating hole. After wear, the arc contact cannot automatically compensate for forward displacement. This leads to a gradual decrease in the contact pressure between the arc contact and the bottom surface of the arc chamber, and may even result in poor contact, further deteriorating the arc extinguishing effect and shortening the product's maintenance cycle and service life.

[0006] Therefore, it is necessary to improve the moving contact mechanism of existing molded case circuit breakers to solve the above-mentioned technical problems. Utility Model Content

[0007] To address the shortcomings in the prior art, this utility model provides a moving contact mechanism for a molded case circuit breaker.

[0008] The technical solution adopted in this utility model is: a moving contact mechanism of a molded case circuit breaker, including a contact support, a main contact rotatably engaged with the contact support, an arc contact rotatably engaged with the contact support, and a return spring for resetting the main contact and the arc contact; The top of the arc contact is provided with an upwardly inclined first contact slope, and a moving contact is provided on the first contact slope. One side of the moving contact has an arc-shaped contact surface. The arc contact head is provided with a rotating hole that rotatably engages with the rotating shaft on the contact support, and the rotating hole has an elongated elliptical structure; The arc contact can slide along the length of the elongated elliptical structure under the action of the return spring to compensate for the displacement of the front end of the arc contact after wear.

[0009] Furthermore, there are at least two main contacts and two arc contacts. The arc contacts are located in the middle of the main contacts and protrude from the main contacts on both sides. Each main contact and each arc contact is equipped with a return spring.

[0010] This application also provides a molded case circuit breaker, including a housing, a moving contact mechanism disposed within the housing, and an arc-extinguishing chamber. The arc-extinguishing chamber is provided with an arc-extinguishing grid, the arc-extinguishing chamber has an opening, the arc-extinguishing grid is located on the side away from the opening of the arc-extinguishing chamber, and the moving contact mechanism is the moving contact mechanism described above. The arc-extinguishing chamber is provided with a second contact slope that cooperates with the first contact slope. The second contact slope extends obliquely in the direction of the arc-extinguishing grid so that the electric arc generated when the arc contact contacts the second contact slope is extinguished by the arc-extinguishing grid.

[0011] Furthermore, the second contact slope is disposed on the bottom surface of the arc-extinguishing chamber and extends upward at an angle from the side away from the arc-extinguishing grid to the side closer to the arc-extinguishing grid.

[0012] Furthermore, the arc-extinguishing grid is inclinedly disposed in the arc-extinguishing chamber, and multiple arc-extinguishing grids are arranged parallel to each other and spaced apart. The inclination direction of the second contact inclined surface is adapted to the inclination direction of the arc-extinguishing grid, so as to guide the electric arc to the arc-extinguishing grid.

[0013] Furthermore, the angle α between the first contact inclined surface and the horizontal plane is 20-50°.

[0014] Furthermore, the angle b between the second contact inclined surface and the bottom surface of the arc-extinguishing chamber is 20-50°.

[0015] Furthermore, after the moving contact and / or the second contact slope wears down, the arc contact automatically moves forward along the long axis of the rotating hole under the action of the return spring to compensate for the contact gap caused by wear, so that the moving contact always remains in contact with the second contact slope.

[0016] The beneficial effects of this utility model are: 1. Significantly Improved Arc Extinguishing Effect: By setting an upwardly inclined first contact slope at the top of the arc contact, and a moving contact with an arc-shaped contact surface on the first contact slope, while simultaneously setting a second contact slope extending inclined towards the arc-extinguishing grid within the arc-extinguishing chamber, the arc-shaped contact surface of the moving contact can slide into contact with the second contact slope when the arc contact rotates during opening. This "slope bearing + contact point contact" structure provides excellent guidance, forcibly and closely guiding the arc generation point to the vicinity of the arc-extinguishing grid, allowing the arc to be captured and extinguished by the arc-extinguishing grid immediately, greatly shortening the arcing time and improving the breaking capacity and safety of the circuit breaker.

[0017] 2. Automatic wear compensation function extends service life: By designing the rotating hole where the arc contact mates with the contact support as an elongated elliptical structure, the arc contact is given a sliding degree of freedom along its length. When the moving contact and the tip of the arc contact wear down due to long-term use, the arc contact can slide along the length of the elongated elliptical rotating hole under the continuous action of the return spring, compensating for the displacement loss caused by wear. This design ensures that there is always sufficient contact pressure between the arc contact and the inclined surface of the arc-extinguishing chamber, avoiding poor contact caused by wear, thereby significantly extending the mechanical and electrical life of the circuit breaker.

[0018] 3. Stable and reliable product performance: Due to the wear compensation mechanism, the circuit breaker can maintain stable contact pressure and arc extinguishing performance throughout its entire life cycle, avoiding the performance degradation problem caused by component wear in traditional circuit breakers, improving product consistency and reliability, and reducing maintenance costs.

[0019] In addition to the objectives, features, and advantages described above, this utility model has other objectives, features, and advantages. The utility model will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] Figure 2 This is a schematic diagram of the arc-extinguishing chamber and the moving contact mechanism.

[0022] Figure 3 This is a schematic diagram of the arc-extinguishing chamber.

[0023] Figure 4This is a schematic diagram of the moving contact mechanism.

[0024] Figure 5 A cross-sectional schematic diagram of the arc-extinguishing chamber and the moving contact mechanism.

[0025] Figure 1-5 In the middle: 1. Contact support; 2. Main contact; 3. Arc contact; 4. Return spring; 5. First contact slope; 6. Rotary hole; 7. Housing; 8. Arc extinguishing chamber; 9. Arc extinguishing grid; 10. Opening; 11. Second contact slope; 12. Moving contact; 13. Arc-shaped contact surface; 14. Rotating shaft. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0028] This utility model provides a moving contact mechanism for a molded case circuit breaker.

[0029] In this embodiment, refer to Figure 1-5 The moving contact mechanism of the molded case circuit breaker includes a contact support 1, a main contact 2 rotatably engaged with the contact support 1, an arc contact 3 rotatably engaged with the contact support 1, and a return spring 4 for resetting the main contact and the arc contact. The top of the arc contact 3 is provided with an upwardly inclined first contact slope 5, and a moving contact 12 is provided on the first contact slope. One side of the moving contact has an arc-shaped contact surface 13. The arc contact is provided with a rotating hole 6 that rotatably engages with the rotating shaft 14 on the contact support. The rotating hole has an elongated elliptical structure. The arc contact can slide along the length of the elongated elliptical structure under the action of the return spring to compensate for the displacement of the front end of the arc contact after wear.

[0030] In the above technical solution, by setting an upwardly inclined first contact slope at the top of the arc contact, when the arc contact mates with the arc-extinguishing chamber, the slope structure can change the initial position of the arc generation, bringing it closer to the arc-extinguishing grid. Simultaneously, the mating hole between the arc contact and the contact support shaft is designed as an elongated ellipse, breaking the single degree of freedom limitation of the traditional circular rotating hole's "pure rotation," adding a translational degree of freedom along the arc contact's length. The return spring not only provides contact pressure but also acts as a driving force, enabling the arc contact to automatically slide and compensate along the length of the elongated elliptical hole after wear. The first contact slope allows the arc generated during tripping to be quickly guided to an area close to the arc-extinguishing grid, shortening the time it takes for the arc to enter the grid, achieving rapid arc extinguishing, and effectively protecting the contact system.

[0031] The rotary hole, in conjunction with the return spring, solves the problem of poor contact caused by wear of the arc contacts in traditional circuit breakers. The arc contacts can automatically move forward to compensate for wear, ensuring sufficient contact pressure throughout the entire lifespan of the circuit breaker, significantly extending its mechanical and electrical lifespan.

[0032] In this design, when the arc contact is disconnected, the silver point of the contact faces the arc extinguishing device. Under the magnetic force of the grid plate, the arc is directly drawn into the arc extinguishing device, where it is cut and cooled to achieve the arc extinguishing effect.

[0033] Specifically, there are at least two main contacts and two arc contacts. The arc contacts are located in the middle of the main contacts and protrude from the main contacts on both sides. Each main contact and each arc contact is equipped with a return spring.

[0034] In this embodiment, at least two main contacts and two arc contacts are used, with the arc contact positioned prominently in the middle of the main contacts. This arrangement ensures that the arc contact contacts the stationary contact before the main contacts during closing, and that the arc contact breaks off after the main contacts during opening, achieving a mechanism where the arc contact closes first and then opens. Each contact is equipped with an independent return spring. This layout utilizes the symmetry of the central position, allowing for a uniform distribution of the arc during generation, and ensuring that the central arc contact receives current immediately. The parallel connection of multiple main contacts effectively reduces contact resistance and improves the circuit breaker's rated current carrying capacity. The centrally located arc contact experiences more balanced force, guiding the arc generated during opening and preventing arc deviation. The independent return spring for each contact ensures that even if one spring fails, the other contacts can still independently reset, improving product reliability.

[0035] Alternatively, the main contact and the arc contact can be integrated into one unit, using a single return spring.

[0036] This application also provides a molded case circuit breaker, including a housing 7, a moving contact mechanism disposed within the housing 7, and an arc-extinguishing chamber 8. The arc-extinguishing chamber 8 is provided with an arc-extinguishing grid 9, and the arc-extinguishing chamber has an opening 10. The arc-extinguishing grid is located on the side away from the opening of the arc-extinguishing chamber, and the moving contact mechanism is the moving contact mechanism described above. The arc-extinguishing chamber is provided with a second contact slope 11 that cooperates with the first contact slope. The second contact slope 11 extends obliquely in the direction of the arc-extinguishing grid so that the electric arc generated when the arc contact contacts the second contact slope is extinguished by the arc-extinguishing grid.

[0037] This solution applies the moving contact mechanism to a complete molded case circuit breaker. By setting a second contact ramp inside the arc-extinguishing chamber that mates with the first contact ramp, and extending the second contact ramp at an angle towards the arc-extinguishing grid, a "ramp guide channel" is formed. When the arc contact rotates downward to open the circuit, the arc-shaped contact surface of the moving contact slides and engages with the second contact ramp. The arc is immediately confined to the area near the arc-extinguishing grid, greatly shortening the arcing time, improving the current-limiting performance and breaking capacity of the circuit breaker, ensuring optimal matching between the mechanism's action and the arc-extinguishing chamber structure, and enhancing the overall safety and reliability of the circuit breaker.

[0038] Specifically, the second contact slope is disposed on the bottom surface of the arc-extinguishing chamber and extends upward at an angle from the side away from the arc-extinguishing grid to the side closer to the arc-extinguishing grid.

[0039] In this embodiment, the second contact ramp is disposed on the bottom surface of the arc-extinguishing chamber, and its inclination direction is upward from the side away from the arc-extinguishing grid to the side closer to the arc-extinguishing grid. This allows the arc to naturally climb upward (towards the arc-extinguishing grid) along the slope after it is generated, reducing the resistance to the arc's movement.

[0040] Specifically, the arc-extinguishing grid is inclinedly disposed in the arc-extinguishing chamber, and multiple arc-extinguishing grids are arranged parallel to each other and spaced apart. The inclination direction of the second contact inclined surface is adapted to the inclination direction of the arc-extinguishing grid, so as to guide the electric arc to the arc-extinguishing grid.

[0041] In this embodiment, multiple arc-extinguishing grids are arranged at an angle, with their tilt direction matching (i.e., parallel or aligned with) the tilt direction of the second contact slope. This ensures that the arc is guided by the second contact slope in a direction perfectly aligned with the entrance direction of the arc-extinguishing grid. The alignment of the slope's guidance direction with the grid's tilt direction creates a seamless connection between the slope guidance and the grid's entrance, allowing the arc to be drawn into the arc-extinguishing grid without obstruction and immediately, achieving optimal arc-extinguishing efficiency.

[0042] Specifically, the angle α between the first contact inclined surface and the horizontal plane is 20-50°.

[0043] In this embodiment, an angle of 20-50° can ensure that the arc is effectively pushed towards the arc-extinguishing grid and that the arc contact slides smoothly during the opening process, avoiding mechanical interference caused by excessive angle.

[0044] Specifically, the angle b between the second contact inclined surface and the bottom surface of the arc-extinguishing chamber is 20-50°.

[0045] In this embodiment, the included angle of 20-50° ensures that the first contact slope and the second contact slope have the maximum contact area when sliding, resulting in uniform force distribution and avoiding deformation or damage to the parts caused by local stress concentration.

[0046] Specifically, after the moving contact and / or the second contact slope wears down, the arc contact automatically moves forward along the long axis of the rotating hole under the action of the return spring to compensate for the contact gap caused by wear, so that the moving contact always remains in contact with the second contact slope.

[0047] When the moving contact and / or the second contact ramp wears down due to long-term use, causing an increase in the contact gap, the return spring's thrust overcomes the frictional force, driving the arc contact to automatically move forward (towards the arc-extinguishing chamber) along the long axis of the rotating hole, filling the gap caused by wear. This achieves "adaptive" wear compensation of the circuit breaker contacts, eliminating the need for manual adjustment and ensuring the long-term stability of product performance.

[0048] Attention all technical personnel: Although this utility model has been described according to the specific embodiments above, the concept of this utility model is not limited to this utility model. Any modification that utilizes the concept of this utility model will be included within the scope of protection of this patent right.

Claims

1. A moving contact mechanism for a molded case circuit breaker, characterized in that, It includes a contact support, a main contact that rotates with the contact support, an arc contact that rotates with the contact support, and a return spring for resetting the main contact and the arc contact; The top of the arc contact is provided with an upwardly inclined first contact slope, and a moving contact is provided on the first contact slope. One side of the moving contact has an arc-shaped contact surface. The arc contact head is provided with a rotating hole that rotatably engages with the rotating shaft on the contact support, and the rotating hole has an elongated elliptical structure; The arc contact can slide along the length of the elongated elliptical structure under the action of the return spring to compensate for the displacement of the front end of the arc contact after wear.

2. The moving contact mechanism of the molded case circuit breaker according to claim 1, characterized in that: There are at least two main contacts and two arc contacts. The arc contacts are located in the middle of the main contacts and protrude from the main contacts on both sides. Each main contact and each arc contact is equipped with a return spring.

3. A molded case circuit breaker, comprising a housing, a moving contact mechanism disposed within the housing, and an arc-extinguishing chamber, wherein an arc-extinguishing grid is provided within the arc-extinguishing chamber, the arc-extinguishing chamber has an opening, and the arc-extinguishing grid is located on the side away from the opening of the arc-extinguishing chamber, characterized in that, The moving contact mechanism is the moving contact mechanism as described in any one of claims 1 or 2; The arc-extinguishing chamber is provided with a second contact slope that cooperates with the first contact slope. The second contact slope extends obliquely in the direction of the arc-extinguishing grid so that the electric arc generated when the arc contact comes into contact with the second contact slope is extinguished by the arc-extinguishing grid.

4. The molded case circuit breaker according to claim 3, characterized in that: The second contact slope The surface is disposed on the bottom surface of the arc-extinguishing chamber and extends upward at an angle from the side away from the arc-extinguishing grid to the side closer to the arc-extinguishing grid.

5. The molded case circuit breaker according to claim 3 or 4, characterized in that: The arc-extinguishing grid The arc-extinguishing grids are arranged at an angle within the arc-extinguishing chamber, with multiple arc-extinguishing grids arranged parallel to each other and spaced apart. The inclination direction of the second contact slope is adapted to the inclination direction of the arc-extinguishing grids, so as to guide the electric arc to the arc-extinguishing grids.

6. The molded case circuit breaker according to claim 3, characterized in that: The angle α between the first contact inclined surface and the horizontal plane is 20-50°.

7. The molded case circuit breaker according to claim 3, characterized in that: The angle b between the second contact inclined surface and the bottom surface of the arc-extinguishing chamber is 20-50°.

8. The molded case circuit breaker according to claim 3, characterized in that: After the moving contact and / or the second contact slope wears down, the arc contact automatically moves forward along the long axis of the rotating hole under the action of the return spring to compensate for the contact gap caused by wear, so that the moving contact always keeps in contact with the second contact slope.

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