Circuit breaker

Abstract

The utility model discloses a circuit breaker, which comprises a moving contact, a static contact, a rotating shaft and an arc isolating cover made of an insulating material, one end of the moving contact is arranged on the rotating shaft, the other end of the moving contact is provided with a moving contact, and the moving contact moves along with the rotating shaft to realize connection / separation of the moving contact and the static contact; the arc isolating cover is arranged on the moving contact and is used for preventing the moving contact from being ablated by an electric arc; wherein one end of the arc-isolating cover extends to the vicinity of the movable contact, and the other end of the arc-isolating cover is inserted into the rotating shaft and is staggered with the rotating shaft; the method has the characteristic that the insulating property can be improved.

Description

Technical Field

[0001] The present application relates to the electrical field of low-voltage switches, and more particularly to a circuit breaker. Background Art

[0002] Molded case circuit breakers often include moving and static contacts, which are connected by contact between the moving and static contacts, and disconnected by separation of the moving and static contacts. In order to prevent the moving contact from being burned by the electric arc, the existing molded case circuit breakers often have an arc shield on the moving contact. However, the existing arc shield has a small coverage area for the moving contact and is only attached to a part of the moving contact. Such an arc shield will expose the part of the moving contact at the arc shield and the rotating shaft, and the insulation performance is poor. The electric arc is very likely to burn this part and the part of the moving contact located inside the rotating shaft.

[0003] The circuit breaker disclosed in CN106571274B adopts the above structure. Figure 1 As shown, it can be clearly seen that the electrical gap from the static contact to the moving contact is larger than the electrical gap from the static contact to the end of the arc shield, so this patent also has the above-mentioned problem.

[0004] Based on this, how to reduce the arc burning of the moving contact at the end of the arc shield is a direction worthy of research. Summary of the invention

[0005] In view of this, the purpose of this application is to overcome the deficiencies in the prior art and to provide a circuit breaker to improve insulation performance.

[0006] A circuit breaker comprises a moving contact, a stationary contact, a rotating shaft and an arc shield made of insulating material; one end of the moving contact is arranged on the rotating shaft, and a moving contact point is arranged on the other end of the moving contact, and the moving contact moves with the rotating shaft to realize the connection / separation of the moving contact point and the stationary contact; the arc shield is arranged on the moving contact to prevent the electric arc from burning the moving contact; wherein, one end of the arc shield extends to the vicinity of the moving contact point, and the other end of the arc shield is inserted into the rotating shaft and is arranged alternately with the rotating shaft.

[0007] With such a design, compared with the prior art, the arc shield will basically cover the exposed part of the moving contact, and the arc shield is inserted into the rotating shaft to form a staggered arrangement with the rotating shaft, which greatly improves the insulation performance and prevents the arc from burning the part of the moving contact close to the rotating shaft.

[0008] In some embodiments of the present application, an insulating protrusion is provided near the rotating shaft of the arc shield, and the insulating protrusion extends in a direction away from the moving contact; when the moving contact is in the extreme position of disconnection, the electrical gap from the static contact to the moving contact is La, the shortest straight-line distance from the static contact to the end of the insulating protrusion is Lb, and the shortest straight-line distance from the end of the insulating protrusion to the part of the moving contact adjacent to the other end of the arc shield is Lc, and La is less than Lb+Lc.

[0009] With this structure, since the other end of the arc shield is inserted into the rotating shaft and an insulating protrusion is provided near the rotating shaft, the creepage distance of the static contact and the moving contact adjacent to the other end of the arc shield should be calculated as the sum of the shortest straight-line distance from the static contact to the end of the insulating protrusion and the shortest straight-line distance from the end of the insulating protrusion to the moving contact adjacent to the other end of the arc shield. That is to say, when the moving contact is in the extreme position of disconnection, the creepage distance of the static contact and the moving contact adjacent to the other end of the arc shield is Lb+Lc. At this time, since La<Lb+Lc, it can effectively prevent the arc from running to the moving contact near the end of the arc shield and burning this part.

[0010] In some embodiments of the present application, a surface of the rotating shaft adjacent to the static contact is a first arcuate surface, and an end of the insulating protrusion extends onto the first arcuate surface.

[0011] With this structural design, the insulation performance can be improved by staggered arrangement of the insulating protrusions and the first arc-shaped surface.

[0012] In some embodiments of the present application, a base is further included, on which a rotating shaft is rotatably disposed; a second arcuate surface matching the first arcuate surface is disposed on the base, and a narrow gap is formed between the first arcuate surface and the second arcuate surface, wherein the width of the narrow gap is 2mm-4mm.

[0013] Compared with the prior art (the prior art is an open design), this structure can effectively reduce the arc gas blowing from here to the direction of the rotating shaft away from the static contact, so that the arc gas is more concentrated in the direction of the rotating shaft toward the static contact.

[0014] In some embodiments of the present application, an arc extinguishing chamber is further included near the static contact, an arc-striking plate is provided on the upper portion of the arc extinguishing chamber, and the head of the moving contact is located in the arc extinguishing chamber; part of the arc isolation cover is located on the upper surface of the head to form an obstruction portion, and there is an intersection between the movement trajectory of the obstruction portion and the arc-striking plate, and the obstruction portion is used to prevent the head of the moving contact from contacting the arc-striking plate.

[0015] With this structure, in the prior art, when the circuit breaker is in extreme disconnection, the moving contact may touch the arc-striking piece because a large current flows through the moving contact and the temperature is high, resulting in adhesion between the moving contact and the arc-striking piece. However, with the design of the blocking part, the arc-isolating cover is made of insulating material. When the circuit breaker is in extreme disconnection, the blocking part will first contact the arc-striking piece to prevent the moving contact from contacting the arc-striking piece, thereby preventing the moving contact from adhering to the arc-striking piece.

[0016] In some embodiments of the present application, the arc shield also includes a first shielding portion and two side shielding portions, the two side shielding portions are connected through the first shielding portion, and the insulating protrusion is connected to the first shielding portion; the first shielding portion is used to shield the lower surface of the moving contact, and the two side shielding portions respectively shield the two side surfaces of the moving contact.

[0017] With this structure, the first shielding portion shields the lower surface of the moving contact, and the lateral shielding portion shields the side surface of the moving contact, so that the moving contact can be better protected.

[0018] In some embodiments of the present application, the two side shielding portions are arranged beyond the upper surface of the moving contact.

[0019] With this structure, the two side shielding parts are arranged beyond the upper surface of the moving contact, which can prevent the moving contact from directly contacting some components inside the circuit breaker, such as preventing the moving contact from contacting the operating mechanism.

[0020] In some embodiments of the present application, one end of the two-sided shielding portion penetrates into the rotating shaft to form the arc shield, and the other end is inserted into the rotating shaft, and the parts of the two-sided shielding portion that penetrate into the rotating shaft are connected through the second shielding portion.

[0021] In some embodiments of the present application, the arc shield and the moving contact are fastened by screws, rivets, interference fit, or snap-fit.

[0022] With this structure, the arc shield and the moving contact can be stably connected by means of screw fastening, rivet fastening, interference fit, or clamping fixation.

[0023] In some embodiments of the present application, the moving contact includes a strip segment, a tail segment, and an arc segment connecting the strip segment and the tail segment, the strip segment is used to set the moving contact, the tail segment is provided with a hole that cooperates with the rotating shaft, and the arc segment is bent in a direction away from the static contact; the arc isolation cover is provided on the strip segment and part of the arc segment, and the shape of the arc isolation cover is consistent with the strip segment and the arc segment.

[0024] In some embodiments of the present application, a stamping groove is provided on the side surface of the moving contact, and the stamping groove is shielded by the arc isolation cover; the density of the moving contact at the stamping groove is greater than the density of the rest of the moving contact.

[0025] By forming a stamping groove through stamping, the density of the moving contact located in this part is greater than the density of the remaining parts, which can improve the strength of the moving contact and make it have better electrical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 A cross-sectional view of a circuit breaker according to Embodiment 1 of the present application is shown;

[0028] Figure 2 A schematic diagram showing the coordination of the rotating shaft, the moving contact, and the arc shield in Example 1 of the present application is shown;

[0029] Figure 3 A schematic diagram of the structure of the moving contact in Embodiment 1 of the present application is shown;

[0030] Figure 4 The schematic diagram of the structure of the arc isolation cover in Example 1 of the present application is shown;

[0031] Figure 5 A cross-sectional view of the rotating shaft, the moving contact, and the arc shield in Example 1 of the present application is shown;

[0032] Figure 6 A partial enlarged view of part A in Example 1 of the present application is shown;

[0033] Figure 7 A schematic structural diagram of an implementation of an obstruction portion in Example 1 of the present application is shown;

[0034] Figure 8 A structural schematic diagram showing another implementation of the obstruction portion in Example 1 of the present application is shown;

[0035] Fig. 9 A schematic diagram of the structure of the circuit breaker in Example 1 of the present application when it is in extreme disconnection is shown. DETAILED DESCRIPTION

[0036] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0037] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0038] In addition, the terms "primary" and "secondary" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "primary" and "secondary" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0039] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In the present application, unless otherwise clearly specified and limited, when a main feature is “above” or “below” a second feature, it can mean that the main feature and the second feature are in direct contact, or the main feature and the second feature are in indirect contact through an intermediate medium. Moreover, when a main feature is “above”, “above” or “above” a second feature, it can mean that the main feature is directly above or obliquely above the second feature, or simply means that the main feature is higher in level than the second feature. When a main feature is “below”, “below” or “below” a second feature, it can mean that the main feature is directly below or obliquely below the second feature, or simply means that the main feature is lower in level than the second feature. Example

[0041] like Figure 1-Figure 9 As shown, an embodiment of the present application provides a circuit breaker, which is a molded case circuit breaker. Of course, the molded case circuit breaker here includes a thermal-magnetic molded case circuit breaker, an electronic molded case circuit breaker, a reclosing circuit breaker, a measuring switch, a fusion switch, etc.

[0042] The circuit breaker includes a base 101, an operating mechanism, a rotating shaft 300, a moving contact 400, a stationary contact 500, an arc isolation cover 600 and an arc extinguishing chamber.

[0043] The base 101 is provided with contact system slots therein. In this embodiment, the number of the contact system slots is three, and the three contact system slots are arranged side by side in a direction that is the width direction of the circuit breaker.

[0044] The operating mechanism is fixed on the base 101. The lower connecting rod of the operating mechanism is connected to the rotating shaft 300, and the rotating shaft 300 can be rotated by controlling the operating mechanism.

[0045] The rotating shaft 300 is inserted into the base 101 and can be rotatably arranged relative to the base 101. The rotating shaft 300 has three moving contact mounting sections 301, and the three moving contact mounting sections 301 are respectively arranged in three contact system grooves. The surface of the moving contact mounting section 301 adjacent to the base 101 and its adjacent surface (it can also be said that the surface adjacent to the static contact 500) is an arc surface, which is a first arc surface 301a, and the corresponding position of the contact system groove (or the base 101) is a second arc surface 101f. A narrow gap 301af is formed between the first arc surface 301a and the second arc surface 101f, and the width of the narrow gap 301af is 2-4mm. The design of this arc surface here will not hinder the movement of the rotating shaft 300. On the contrary, due to the design of the narrow gap 301af, the arc gas flowing from the narrow gap 301af to the rear of the circuit breaker (that is, the direction of the rotating shaft 300 away from the static contact 500) during disconnection can be reduced.

[0046] There are three moving contacts 400, and the three moving contacts 400 correspond to the three moving contact mounting sections 301 respectively. Specifically, one end of the moving contact 400 extends into the moving contact mounting section 301, and is rotatably connected with the moving contact mounting section 301 through the second pin shaft; the other end of the moving contact 400 extends in a direction away from the moving contact mounting section 301, and the moving contact is arranged at this end. The moving contact 400 can be divided into a strip section 400a, an arc section 400b and a tail section 400c along its length direction. The strip section 400a and the tail section 400c are connected through the arc section 400b, the moving contact is arranged in the strip section 400a, the arc section 400b is bent in a direction away from the static contact 500, and the hole cooperating with the second pin shaft is arranged on the tail section 400c. Relative to the moving contact mounting section 301, the strip section 400a is outside the moving contact mounting section 301, while the tail section 400c is inside the moving contact mounting section 301, and the arc section 400b is partially inside and outside the moving contact mounting section 301.

[0047] There are three static contacts 500, which correspond to the three moving contacts 400 respectively. The three static contacts 500 are arranged in three contact system slots. The circuit breaker is connected by the contact between the moving contact and the static contact 500, and the circuit breaker is disconnected by the separation between the moving contact and the static contact 500.

[0048] There are also three arc extinguishing chambers, which are arranged near the static contact 500 and are used to extinguish the arc generated between the moving and static contacts 400 and 500. The arc extinguishing chamber has a plurality of stacked arc extinguishing grids and an arc-starting plate 701. In the height direction, the arc-starting plate 701 is located above all the arc extinguishing grids, and the arc-starting plate 701 is used to attract the arc from the moving contact 400.

[0049] The arc shield 600 is arranged on the moving contact 400 to prevent the arc from burning the moving contact 400. One end of the arc shield 600 is close to the moving contact, and the other end of the arc shield 600 is inserted into the moving contact mounting section 301, and the two are staggered, so that the insulation performance can be greatly improved.

[0050] An insulating protrusion 603 is provided on the arc shield 600 near the rotating shaft 300. The insulating protrusion 603 extends in a direction away from the moving contact 400, which is equivalent to adding an insulating protrusion 603 between the tail section 400c of the moving contact 400 and the static contact 500, thereby increasing the electrical gap. The electrical clearance relationship here is as follows: when the moving contact 400 is in the extreme position of disconnection, the electrical clearance from the static contact 500 to the moving contact is La; the shortest straight-line distance from the static contact 500 to the end (also the top) of the insulating protrusion 603 is Lb, and the shortest straight-line distance from the end (also the top) of the insulating protrusion 603 to the part of the moving contact 400 adjacent to the arc-isolating cover 600 extending into the moving contact mounting section 301 is Lc. At this time, the electrical clearance from the static contact 500 to the part of the moving contact 400 adjacent to the arc-isolating cover 600 extending into the moving contact mounting section 301 is Lb+Lc, La<Lb+Lc. Meeting this electrical clearance can effectively prevent the arc from running to the rear of the moving contact 400 and burning this part.

[0051] Here, the insulating protrusion 603 is roughly arc-shaped and is arranged adjacent to the first arc surface 301a, and the end of the insulating protrusion 603 extends onto the first arc surface 301a. The insulating performance can be improved by staggered arrangement of the insulating protrusion 603 and the first arc surface 301a.

[0052] The specific structure of the arc shield 600 includes a first shielding portion 601 and two lateral shielding portions 602. The first shielding portion 601 is located on the lower surface of the moving contact 400, and is specifically used to shield the lower surface of the moving contact 400 exposed outside the moving contact mounting section 301 (of course, the moving contact point will not be shielded here, and the moving contact point is exposed). The two lateral shielding portions 602 shield the two side surfaces of the moving contact 400, and are specifically used to shield the two side surfaces of the moving contact 400 exposed outside the moving contact mounting section 301. Here, the arc shield 600 is arranged on the strip segment 400a and part of the arc segment 400b, that is, the shape of the arc shield 600 is consistent with the shape of this part of the moving contact 400 (the strip segment 400a, the arc segment 400b). In this embodiment, the arc shield 600 is inserted into the moving contact mounting section 301 through the two side shielding portions 602, specifically, the two side shielding portions 602 are inserted into the moving contact mounting section 301, and the inserted portions are connected through the second shielding portion 604. The insulating protrusion 603 is connected to the first shielding portion 601 and is located close to the first arc surface 301a.

[0053] Here, the arc shield 600 and the moving contact 400 are fixed by rivets, and rivet holes are provided on the moving contact 400 and the lateral shielding portion 602, and the two are fixed by rivets. In addition, screw fastening, interference fit, clamping fixation and other methods can also be used for fixing.

[0054] In order to prevent the moving contact 400 from sticking to the arc-striking piece 701 during the extreme disconnection, part of the arc shield 600 is located on the upper surface of the head of the moving contact 400 to form an obstruction 600a, where the movement trajectory of the obstruction 600a intersects with the arc-striking piece 701, that is, when the circuit breaker is at the extreme disconnection, the obstruction 600a will first contact the arc-striking piece 701, thereby preventing the moving contact 400 from contacting the arc-striking piece 701, thereby preventing the moving contact 400 from sticking to the arc-striking piece 701. There are many implementations in which the obstruction 600a is located on the upper surface of the head of the moving contact 400:

[0055] like Figure 6 As shown, as an embodiment, the two-side shielding parts 602 are arranged beyond the upper surface of the moving contact 400, and the exceeding part of the two-side shielding parts 602 located at the head of the head moving contact 400 forms an obstruction part 600a. This way that the two-side shielding parts 602 exceed the upper surface of the moving contact 400 can not only prevent the moving contact 400 from contacting with the arc-starting piece 701, but also prevent the moving contact 400 from contacting and sticking with other parts inside the circuit breaker.

[0056] like Figure 7As shown, as a modified embodiment, in this embodiment, the two side shielding portions 602 are only arranged beyond the upper surface of the moving contact 400 at the head position, forming an obstruction portion 600a.

[0057] like Figure 8 As shown, as another modified embodiment, an obstruction portion 600a is provided on the upper surface of the head of the moving contact 400, and the obstruction portion 600a is connected to the two side shielding portions 602, that is, the obstruction portion 600a here is directly provided on the upper surface of the head of the moving contact 400.

[0058] Regardless of which of the above methods is used to form the obstruction portion 600 a , it can effectively prevent welding between the moving contact 400 and the arc-starting piece 701 .

[0059] A stamping groove 400d is opened on the side surface of the moving contact 400, and the stamping groove 400d is set on the strip segment 400a and part of the arc segment 400b. The stamping groove 400d is blocked by the lateral shielding portion 602 of the arc isolation cover 600. The design of the stamping groove 400d here can make the density of the moving contact 400 here greater than the density of other parts, thereby effectively improving the strength of the moving contact 400.

[0060] Although a 3-pole circuit breaker is used as an example in this embodiment, the above structure is also applicable to a 2-pole circuit breaker or a 4-pole circuit breaker. Similarly, this embodiment provides an implementation scheme of a single moving contact, and this structure is also applicable to an implementation scheme of multiple moving contacts arranged in parallel.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without contradiction.

[0062] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A circuit breaker, comprising a moving contact, a stationary contact, a rotating shaft and an arc shield made of insulating material; one end of the moving contact is arranged on the rotating shaft, and a moving contact is arranged on the other end of the moving contact, and the moving contact moves with the rotating shaft to realize the connection / disconnection of the moving contact and the stationary contact; the arc shield is arranged on the moving contact to prevent the electric arc from burning the moving contact; characterized in that: One end of the arc-isolating cover extends to the vicinity of the moving contact, and the other end of the arc-isolating cover is inserted into the rotating shaft and is arranged alternately with the rotating shaft.

2. A circuit breaker according to claim 1, characterized in that: An insulating protrusion is provided near the rotating shaft of the arc isolation cover, and the insulating protrusion extends in a direction away from the moving contact; when the moving contact is in the extreme position of disconnection, the electrical gap from the static contact to the moving contact is La, the shortest straight-line distance from the static contact to the end of the insulating protrusion is Lb, and the shortest straight-line distance from the end of the insulating protrusion to the part of the moving contact adjacent to the other end of the arc isolation cover is Lc, and La<Lb+Lc.

3. A circuit breaker according to claim 2, characterized in that: The surface of the rotating shaft adjacent to the stationary contact is a first arc-shaped surface, and the end of the insulating protrusion extends onto the first arc-shaped surface.

4. A circuit breaker according to claim 3, characterized in that: It also includes a base, on which a rotating shaft is rotatably arranged; a second arc surface matching the first arc surface is arranged on the base, a narrow gap is formed between the first arc surface and the second arc surface, and the width of the narrow gap is 2mm-4mm.

5. A circuit breaker according to claim 1, characterized in that: It also includes an arc extinguishing chamber located near the static contact, with an arc-striking piece provided on the upper part of the arc extinguishing chamber, and the head of the moving contact is located in the arc extinguishing chamber; part of the arc isolation cover is located on the upper surface of the head to form an obstruction part, and there is an intersection between the movement trajectory of the obstruction part and the arc-striking piece, and the obstruction part is used to prevent the head of the moving contact from contacting the arc-striking piece.

6. A circuit breaker according to claim 1, characterized in that: The arc shield also includes a first shielding portion and two side shielding portions, the two side shielding portions are connected through the first shielding portion, the first shielding portion is used to shield the lower surface of the moving contact, and the two side shielding portions respectively shield the two side surfaces of the moving contact.

7. A circuit breaker according to claim 6, characterized in that: Both side shielding parts are arranged beyond the upper surface of the moving contact; and / or, one end of the side shielding part penetrates into the rotating shaft to form the arc shield, and the other end is inserted into the rotating shaft, and the parts of the side shielding part penetrating into the rotating shaft are connected through the second shielding part.

8. A circuit breaker according to claim 1, characterized in that: The arc shield and the moving contact are fastened by screws, rivets, interference fit or clamping.

9. A circuit breaker according to claim 1, characterized in that: The moving contact includes a strip segment, a tail segment and an arc segment connecting the strip segment and the tail segment. The strip segment is used to set the moving contact. The tail segment is provided with a hole that cooperates with the rotating shaft. The arc segment is bent in a direction away from the static contact. The arc shield is provided on the strip segment and part of the arc segment. The shape of the arc shield is consistent with the strip segment and the arc segment.

10. A circuit breaker according to claim 1, characterized in that: A stamping groove is provided on the side surface of the moving contact, and the stamping groove is shielded by the arc isolation cover; the density of the moving contact at the stamping groove is greater than the density of the rest of the moving contact.

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