Moving contact of miniature circuit breaker and miniature circuit breaker

Abstract

The utility model relates to the field of miniature circuit breakers, in particular to a moving contact of a miniature circuit breaker and the miniature circuit breaker. The utility model provides the moving contact with two gears of thickness, the driving section with smaller thickness can realize the forming of a hole groove structure with smaller edge gap through stamping, the conductive section with larger thickness forms a conductive part between the moving contact and the electric connection part, and the larger thickness can realize larger cross section area, thereby reducing temperature rise. The utility model provides a single-breakpoint large-current miniature circuit breaker, the large-current specification requirement of a 80A-125A miniature circuit breaker is met under the width of 20mm-30mm, the problem that the uniformity of the pressure and synchronism of a contact adopting a double-breakpoint structure in the current market cannot be ensured is solved, the application risk of a product is reduced, the power consumption is reduced, and the long-term operation requirement of the product is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of small circuit breaker, concretely relates to a small circuit breaker's moving contact and small circuit breaker. BACKGROUND

[0002] Small circuit breaker, also called micro circuit breaker, is mainly applied to industry, commerce, high layer and various places such as civil residence, is used for AC and DC, rated voltage DC2000V and AC2000V below, as the overload and short circuit protector of distribution line and equipment, also can be used as line infrequent on-off operation and conversion. The width of existing small circuit breaker 1P is 1 module, that is 18mm (63A and below specification) or 27mm (80A-125A), however, at present, small circuit breaker is developing towards intelligentization and miniaturization, and realizing 125A small circuit breaker high-performance product design under 18mm-27mm module will become the development trend in circuit breaker industry, and also conforms to the policy of national opening source and saving flow. The small circuit breaker of conventional structure cannot meet the application requirement of 125A large current, and the conventional product has high temperature rise at 2000m altitude, and is easy to burn out the product and line, and the burning out is more serious in the case of high temperature at 3000m-5000m altitude and summer outdoor operation.

[0003] At present, the difficulty of developing large-current small circuit breaker mainly lies in that: the thickness of the moving contact of the present small circuit breaker is thin, generally about 1.5mm, and it is used for large current and leads to high temperature rise; if the thickness of the moving contact is increased to meet the use requirement of 80A-125A large current, the thickness of the moving contact needs to be increased to more than 3mm, however, the present process is difficult to achieve the preparation of the moving contact with such thickness, and the stamping equipment at present cannot realize the stamping of the part with small edge gap of thick copper material, in addition, the thick moving contact leads to the increase of the overall thickness of the operating mechanism of the circuit breaker, and the module specification of the small circuit breaker cannot meet the installation of the thicker operating mechanism.

[0004] Based on the above reasons, the mainstream technical idea for realizing the reduction of internal temperature rise of the large-current small circuit breaker at present is to adopt the double-break contact structure, however, due to the increase of the number of parts and assembly process, the cost is obviously increased compared with the small circuit breaker with single-break contact structure, and the contact pressure and synchronism of the double-break structure cannot be guaranteed after closing, and the problem of product burning out often occurs in market application. UTILITY MODEL CONTENTS

[0005] The utility model aims at overcoming the shortcomings and deficiencies in the prior art, and provides a small circuit breaker's moving contact and small circuit breaker.

[0006] The utility model discloses a technical scheme as follows: A movable contact of a small circuit breaker, comprising a driving section and a conductive section, the driving section is provided with a connecting hole along its thickness direction, the conductive section has an electric connection part for connecting with a conductive wire and a movable contact point for cooperating with a static contact; the thickness of the conductive section is D1, the thickness of the driving section is D2, and D1 is greater than D2.

[0007] Preferably, D1 is 3-5mm, and D2 is 1.0-2.0mm.

[0008] One side or both sides of the conductive section are protruded relative to the side of the driving section, and the transition between them is inclined.

[0009] A single-break-point large-current small circuit breaker, comprising a shell, an operating mechanism, a static contact, a first wiring terminal and a second wiring terminal of the small circuit breaker as described above are arranged in the shell, the operating mechanism comprises a lock catch, a trip catch and a movable contact holder, the movable contact is hingedly connected with the movable contact holder through a first connecting shaft passing through the connecting hole, the electric connection part is electrically connected with the first wiring terminal through the conductive wire, the static contact is electrically connected with the second wiring terminal, and the movable contact rotates under the drive of the operating mechanism to separate or connect the movable contact point and the static contact.

[0010] Preferably, the lock catch and the movable contact holder are hingedly connected with the shell through a second connecting shaft, the driving section is provided with an arc-shaped hole along its thickness direction, and the arc-shaped hole is for the second connecting shaft to pass through; the trip catch and the movable contact holder are hingedly connected through a third hinged shaft; the operating mechanism comprises a handle and a connecting rod, and the handle, the connecting rod and the trip catch are connected in sequence.

[0011] Preferably, an arc extinguishing assembly is arranged in the shell, the arc extinguishing assembly comprises an arc extinguishing chamber, a slit assembly is arranged on one side of the inlet of the arc extinguishing chamber, a magnetic enhancement assembly is arranged outside the slit assembly, the slit assembly is composed of two oppositely arranged gas generating plates, and a slit for the static contact and the movable contact to extend into is formed between the two gas generating plates.

[0012] Preferably, a gas return inclined surface is arranged on the side of the gas generating plate close to the inlet of the arc extinguishing chamber.

[0013] Preferably, the arc extinguishing assembly comprises an arc guiding sheet, the arc guiding sheet has a first arc guiding part extending to the opening of the arc extinguishing chamber or the side surface thereof and a second arc guiding part corresponding to the movable contact at the breaking position.

[0014] An arc blocking plate is arranged on the inner wall of the shell corresponding to the outside of the static contact.

[0015] The utility model discloses a beneficial effect as follows: the utility model provides a movable contact head with two thicknesses, wherein the driving section of smaller thickness can realize the forming of the hole groove structure with smaller edge gap through stamping, the conductive section of larger thickness constitutes the conductive part between the movable contact and the electric connection part, and the larger thickness can realize larger cross -section area, thereby reducing temperature rise. The utility model discloses a single-breakpoint large -current small -size circuit breaker for the first time, can satisfy 80A-125A large -current breaking requirement, does not exist the problem that the contact pressure and synchronism of mainstream double -breakpoint structure on the market cannot guarantee uniformity, reduces product application risk and reduces power consumption. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings obtained according to these drawings without creative labor still belong to the scope of the utility model.

[0017] Figure 1 It is the structure schematic drawing of movable contact head of the utility model embodiment 1, (a) is the perspective view, (b) is the side view;

[0018] Figure 2 It is the structure schematic drawing of movable contact copper material drawing mould of the utility model embodiment 1;

[0019] Figure 3 It is the flow chart of the preparation of movable contact of the utility model embodiment 1;

[0020] Figure 4 It is the structure schematic drawing of movable contact head of the utility model embodiment 2, (a) is the perspective view, (b) is the side view;

[0021] Figure 5 It is the structure schematic drawing of small -size circuit breaker of the utility model embodiment 3;

[0022] Figure 6 It is the internal structure schematic drawing of small -size circuit breaker of the utility model embodiment 3;

[0023] Figure 7 It is the structure schematic drawing of operating mechanism of small -size circuit breaker of the utility model embodiment 3;

[0024] Figure 8 It is the structure schematic drawing of arc extinguishing mechanism of small -size circuit breaker of the utility model embodiment 3;

[0025] Figure 9 It is the explosion schematic drawing of arc extinguishing mechanism of small -size circuit breaker of the utility model embodiment 3.

[0026] Figure 10 It is the sectional view of arc extinguishing mechanism of small circuit breaker of the utility model embodiment 3;

[0027] Figure 11 It is the structure schematic view of one gas production plate of small circuit breaker of the utility model embodiment 3;

[0028] Figure 12 It is the structure schematic view of another angle of small circuit breaker of the utility model embodiment 3;

[0029] Figure 13 It is Figure 12 It is the enlarged schematic view of middle A part;

[0030] Figure 14 It is the structure schematic view of small circuit breaker of the utility model embodiment 4;

[0031] Figure 15 It is the explosion view of short-circuit heat dissipation assembly of small circuit breaker of the utility model embodiment 4;

[0032] In the figure,

[0033] Moving contact-100, driving section-110, connecting hole-111, arc-shaped hole-112, spring hook hole-113, conductive section-120, electric connection part-121, moving contact point-122;

[0034] Static contact-200;

[0035] Copper material drawing die-300, first die cavity-310, second die cavity-320;

[0036] Shell-400, arc baffle-410;

[0037] Operating mechanism-500, lock catch-510, trip catch-520, moving contact holder-530, first connecting shaft-540, second connecting shaft-550, third hinged shaft-560, handle-570, connecting rod-580;

[0038] Electromagnetic release-610, temperature sensing double gold sheet-620;

[0039] First wiring terminal-710, second wiring terminal-720;

[0040] Arc extinguishing assembly-800, arc extinguishing chamber-810, slit assembly-820, gas production plate-821, gas return inclined surface-822, magnetic enhancement assembly-830, magnetic enhancement plate-831, connecting strip-832, arc striking piece-840, first arc striking part-841, second arc striking part-842;

[0041] Shorting heat dissipation assembly-900, shorting row-910, connecting main plate-911, connecting foot-912, heat sink-920, bottom plate-921, heat dissipation fin-922, heat dissipation cover-930, back plate-931, upper end plate-932, side plate-933. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model will be described further in detail below in combination with the drawings.

[0043] It should be noted that all the expressions of "first" and "second" in the embodiments of the utility model are used to distinguish two same name non-same entities or non-same parameters, and it can be seen that "first" and "second" are only for the convenience of expression, and should not be understood as the limitation of the embodiments of the utility model, and the subsequent embodiments will not be described one by one.

[0044] The direction and position terms mentioned in the utility model, such as up, down, front, back, left, right, inside, outside, top, bottom, side, etc., are only the direction or position of the drawings. Therefore, the direction and position terms used are used to explain and understand the utility model, and are not limited to the protection scope of the utility model.

[0045] Embodiment 1:

[0046] A moving contact 100 of a small circuit breaker, as shown in Figure 1 It includes a driving segment 110 and a conductive segment 120.

[0047] The driving segment 110 is used for cooperating with the operating mechanism 500, and has a connecting hole 111, an arc-shaped hole 112 and a spring hook hole 113 opened along the thickness direction thereof. The thickness of the driving segment 110 is D2, and since the internal space of the small circuit breaker is limited, the sizes of the connecting hole 111, the arc-shaped hole 112 and the spring hook hole 113 are very small, the edge gap is small, and D2 needs to be set to be small, so that the forming of the connecting hole 111, the arc-shaped hole 112 and the spring hook hole 113 can be realized by stamping, and D2 is preferably set to be 1.0-2.0mm, and too thin will affect the strength, so that there is a risk of breaking during the opening and closing process, and too thick will increase the processing difficulty, and will affect the overall thickness of the operating mechanism, and the overall thickness of the operating mechanism is too thick, which cannot be installed into the small circuit breaker.

[0048] The conductive section 120 has an electrical connection part 121 for forming a connection with a conductive wire and a movable contact 122 for cooperating with the fixed contact 200, that is, the conductive section 120 constitutes a conductive part of the direct wire connection of the conductive wire and the movable contact 122. The thickness D1 of the conductive section 120 affects the cross-sectional area of the conductor, thereby affecting the temperature rise. In the present embodiment, D1 is set to be relatively larger than D2, and the temperature rise of the movable contact 100 during conduction is not affected by the thickness of the driving section 110, thereby not being limited by the shortcomings of the stamping process, so that the movable contact 100 of the small circuit breaker meeting the temperature rise requirement of large current is obtained. Preferably, D1 is set to be greater than 3 mm. At the same time, in order to achieve rapid arc extinction and better reduce the temperature rise, it is necessary to provide a gas generating slit assembly on both sides of the movable contact 100 in the small circuit breaker, and therefore, D1 is preferably set to be less than 5 mm to provide sufficient space for installing the slit assembly in the small circuit breaker.

[0049] In the present embodiment, one side wall of the conductive section 120 is protruded relative to the same side wall of the driving section 110, and the two side walls are transitioned by a slope, and the other side wall between the two side walls is located in the same plane as the same side wall of the driving section 110. The slope transition can increase the strength of the part where the driving section 110 and the conductive section 120 are connected.

[0050] The preparation method of the movable contact of the present embodiment is also different from the prior art. The preparation method of the present embodiment comprises the following steps:

[0051] Step a, designing a copper material stretching die 300, as shown in the drawing, the die cavity of the copper material stretching die 300 comprises a first die cavity 310 with a D1 width and a second die cavity 320 with a D2 width; Figure 2

[0052] Step b, as shown in the drawing, the contact material is drawn through the die cavity of the copper material stretching die 300 to form a long strip-shaped copper material with two thicknesses of D1 and D2; Figure 3

[0053] Step c, stamping the long strip-shaped copper material to obtain the movable contact.

[0054] By the movable contact provided in the present embodiment, a single-break-point large-current small circuit breaker can be obtained.

[0055] Embodiment 2:

[0056] The present embodiment provides a movable contact 100 of a small circuit breaker. The preparation method of the present embodiment is completely the same as that of embodiment 1, and the structure of the movable contact 100 of the present embodiment is slightly different from that of embodiment 1, as shown in the drawing. In the present embodiment, both side walls of the conductive section 120 of the movable contact 100 are protruded relative to the same side wall of the driving section 110, and the two side walls are transitioned by a slope. Figure 4

[0057] ​​​Embodiment 3

[0058] The embodiment provides a miniature circuit breaker, which comprises a shell 400, as shown in the drawings, and a movable contact 100, a static contact 200, an operating mechanism 500, a tripping driving mechanism, a first wiring terminal 710, a second wiring terminal 720 and an arc extinguishing assembly 800 which are arranged in the shell 400. Figure 6

[0059] The electric connection part 121 of the movable contact 100 is electrically connected with the first wiring terminal 710 through a conductive wire, the static contact 200 is electrically connected with the second wiring terminal 720, and the first wiring terminal 710 is electrically connected with the second wiring terminal 720 when the movable contact 100 is engaged with the static contact 200, and the first wiring terminal 710 is disconnected with the second wiring terminal 720 when the movable contact 100 is separated from the static contact 200.

[0060] The operating mechanism 500 comprises a handle 570, a connecting rod 580, a lock catch 510, a trip catch 520 and a movable contact holder 530, as shown in the drawings. Figure 7 The trip catch 520 is hinged with the movable contact holder 530 through a third hinge shaft 560, the movable contact 100 is hinged with the movable contact holder 530 through a first connecting shaft 540 which passes through the connecting hole 111, the lock catch 510 and the movable contact holder 530 are hinged with the shell 400 through a second connecting shaft 550, the driving section 110 is provided with an arc-shaped hole 112 along the thickness direction of the driving section 110, the arc-shaped hole 112 is provided for the second connecting shaft 550 to pass through, and a spring hook hole 113 is arranged between the shell 400 and the movable contact 100, the lock catch 510 and the trip catch 520 have a reclosing state and a tripping state, in the reclosing state, the handle 570 can be used to realize the opening and closing of the movable contact 100, when the lock catch 510 is rotated to the tripping state, the spring pulls the movable contact 100 to automatically open the movable contact 100.

[0061] The tripping driving mechanism is used to drive the lock catch 510 to rotate from the reclosing state to the tripping state, and specifically comprises an electromagnetic tripping device 610 which is electrically connected between the static contact 200 and the second wiring terminal 720 and a temperature-sensitive double contact 620 which is electrically connected between the movable contact 100 and the first wiring terminal 710, so as to realize the protection of short circuit, overcurrent and overheating, and the specific induction driving principle is basically the same as the existing one, and is not described in detail.

[0062] The arc extinguishing assembly 800 comprises a fixed contact 810, a movable contact 820, a fixed contact holder 830 and a movable contact holder 840, as shown in the drawings. Figure 8 , Figure 9 ​As shown, the arc extinguishing assembly 800 includes an arc extinguishing chamber 810, and a slit assembly 820 is arranged at the inlet side of the arc extinguishing chamber 810. A magnetic enhancement assembly 830 is arranged outside the slit assembly 820. The slit assembly 820 is composed of two oppositely arranged gas production plates 821, and a slit is formed between the two gas production plates 821 for the static contact 200 and the moving contact 100 to extend into. The arc extinguishing chamber 810 includes a plurality of arc extinguishing fins to achieve rapid arc extinguishing. The housing 400 is provided with an exhaust port corresponding to the outlet of the arc extinguishing chamber 810. The slit assembly 820 is arranged on both sides of the moving contact 100 and the static contact 200. During the opening process, the arc formed between the moving contact 100 and the static contact 200 acts on the gas production plate 821, forming a gas blowing effect, so that the arc is quickly blown to the arc extinguishing chamber 810, avoiding the increase of temperature rise. The magnetic enhancement assembly 830 is arranged outside the slit assembly 820, effectively forming a magnetic blowing effect, improving the arc striking efficiency, and thus making the arc extinguishing effect better.

[0063] Specifically, as shown in Figure 9 The magnetic enhancement assembly 830 has two magnetic enhancement members. The magnetic enhancement member has a magnetic enhancement plate 831 located outside the gas production plate 821 and a connecting strip 832 extending from one side of the magnetic enhancement plate 831 to one side of the gas production plate 821. The connecting strips 832 of the two magnetic enhancement members are fixedly connected, and the two gas production plates 821 are respectively fixed on the two magnetic enhancement plates 831.

[0064] Further, as shown in Figure 10 , Figure 11 The gas production plate 821 is provided with a gas return inclined surface 822 at the side close to the inlet of the arc extinguishing chamber 810. When the gas flow with arc collides with the arc extinguishing fins of the arc extinguishing chamber 810, there will be a certain back blowing effect. The back blowing gas flow collides with the gas return inclined surface 822 and returns again, reducing the possibility of returning to the slit.

[0065] The arc extinguishing assembly 800 includes an arc striking piece 840. The arc striking piece 840 has a first arc striking part 841 extending to the opening of the arc extinguishing chamber 810 or the side surface thereof, and a second arc striking part 842 corresponding to the moving contact 100 at the breaking position. As shown in Figure 10 During the opening rotation of the moving contact 100, the second arc striking part 842 can form a good arc striking effect on the moving contact 100. Further, the connecting strip 832 of the magnetic enhancement assembly 830 is located outside the arc striking piece 840.

[0066] The double gold sheet 620 is directly connected with the arc striking piece 840, avoiding the temperature in the arc extinguishing chamber 810 being too high.

[0067] As shown in Figure 12 , Figure 13As shown, the inner wall of the shell 400 corresponding to the outer side of the static contact 200 is provided with an arc baffle 410. The arc is prevented from escaping to the operating mechanism 500, affecting the operation of the operating mechanism 500. The wiring part of the static contact 200 and the conduction part matched with the moving contact 100 are connected by bending, and the arc baffle 410 is L-shaped, corresponding to the bending part between the wiring part and the conduction part of the static contact 200.

[0068] The mainstream large-current small circuit breaker on the market is a double-breakpoint structure. The 125A large-current small circuit breaker of the embodiment is compared with a 125A large-current small circuit breaker of a foreign brand with a double-breakpoint structure that is well received by the market. The comparison results are shown in Table 1. The product of the present application is compared with similar international 80A-125A products, and the temperature rise is reduced by more than 30%, reducing the application risk and power consumption of the product.

[0069] The arc extinguishing assembly of the embodiment is subjected to load life test, and the test results are very significant, which are obviously better than the data of the conventional large-current small circuit breaker.

[0070]

[0071] Embodiment 4:

[0072] As shown in the drawings, Figure 14 The short-circuit heat dissipation assembly 900 is detachably installed between the short-circuit heat dissipation assembly 900 and the small circuit breaker body.

[0073] The short-circuit heat dissipation assembly 900 includes a short-circuit row 910, a heat sink 920, and a heat dissipation cover 930. The short-circuit row 910 includes a connection main plate 911 and a connection foot 912. The heat sink 920 includes a bottom plate 921 and a heat dissipation fin 922. The bottom plate 921 is attached to and fixedly connected with the connection main plate 911. The heat dissipation cover 930 includes a back plate 931, an upper end plate 932, and a side plate 933. The back plate 931 is located outside the heat dissipation fin 922 and is provided with a heat dissipation through hole. The side plate 933 is located on both sides of the heat sink 920, so that the heat dissipation cover 930 covers the heat sink 920 outside to form a protection effect on the heat sink 920. The heat dissipation cover 930 is detachably connected with the shell 400 of the small circuit breaker body. When the short-circuit row 910 is plugged with the wiring terminal of the small circuit breaker body, and when the heat dissipation cover 930 is connected with the shell 400 of the small circuit breaker body, the short-circuit row 910 and the heat sink 920 are simultaneously limited, so that the short-circuit row 910 and the heat sink 920 are kept connected with the wiring terminal of the small circuit breaker body.

[0074] The connecting feet 912 are connected to the same side of the short-circuiting row 910 and the angle between the connecting main plate and the connecting feet 912 is 80-100°, and the heat dissipation fins 922 are arranged on the bottom plate 921 at intervals and the angle between the heat dissipation fins 922 and the bottom plate 921 is 80-100°. The connecting feet 912 can be electrically connected to the second connecting terminal 720 of the two-pole circuit breaker to realize short-circuiting series connection of the two-pole circuit breaker.

[0075] Specifically, the short-circuiting row 910 and the heat sink 920 can be integrated or separated, and compared with the integrated structure, the separated structure is more convenient for production, and can be selected according to actual conditions. In the embodiment, the connecting main plate 911 and the bottom plate 921 are in a separated form. The bottom plate 921 of the heat sink is provided with heat dissipation fins 922 at equal intervals. The included angle between the connecting feet 912 and the connecting main plate 911, the heat dissipation fins 922 and the bottom plate 921 is not limited herein, and can be set according to actual conditions. In the embodiment, the optimal scheme is that the connecting main plate 911, the heat dissipation fins 922 and the bottom plate 921 are perpendicular to each other, the space utilization rate is high, and based on the structure of the small circuit breaker body, more heat dissipation fins can be arranged on the side of the small circuit breaker body to improve the heat dissipation efficiency.

[0076] The above only discloses preferred embodiments of the utility model, and of course cannot limit the scope of the utility model, so equivalent changes made according to the utility model claims still belong to the scope covered by the utility model.

Claims

1. A moving contact of a miniature circuit breaker, characterized by: It includes a driving section (110) and a conductive section (120), the driving section (110) is provided with a connecting hole (111) along its thickness direction, the conductive section (120) has an electric connection part (121) for connecting with a conductive wire and a movable contact (122) for cooperating with a static contact (200); the thickness of the conductive section (120) is D1, the thickness of the driving section (110) is D2, and D1 is greater than D2.

2. A moving contact of a miniature circuit breaker according to claim 1, characterized in that: D1 is 3-5 mm, and D2 is 1.0-2.0 mm.

3. The movable contact of a miniature circuit breaker according to claim 1, characterized in that: One side or both sides of the conductive section (120) are protruded relative to the side of the driving section (110), and the transition between them is a slope.

4. A single-break large-current miniature circuit breaker, comprising a shell (400), an operating mechanism (500), a movable contact (100) of the miniature circuit breaker according to any one of claims 1-3, a static contact (200), a first wiring terminal (710), and a second wiring terminal (720) arranged in the shell (400), the operating mechanism (500) comprising a lock catch (510), a trip catch (520), and a movable contact holder (530), the movable contact (100) being hingedly connected to the movable contact holder (530) through a first connecting shaft (540) passing through the connecting hole (111), the electric connection part (121) being electrically connected to the first wiring terminal (710) through a conductive wire, the static contact (200) being electrically connected to the second wiring terminal (720), and the movable contact (100) being rotated under the drive of the operating mechanism (500) to separate or engage the movable contact (122) with the static contact (200).

5. The single-break, high-current, miniature circuit breaker of claim 4, wherein: The lock catch (510) and the movable contact holder (530) are hingedly connected to the shell (400) through a second connecting shaft (550), the driving section (110) is provided with an arc-shaped hole (112) along its thickness direction, and the arc-shaped hole (112) is for the second connecting shaft (550) to pass through; the trip catch (520) is hingedly connected to the movable contact holder (530) through a third hinging shaft (560); and the operating mechanism (500) comprises a handle (570) and a connecting rod (580), which are connected in sequence.

6. The single-break, high-current, miniature circuit breaker of claim 4, wherein: An arc extinguishing assembly (800) is arranged in the shell (400), the arc extinguishing assembly (800) comprises an arc extinguishing chamber (810), a slit assembly (820) is arranged at the inlet side of the arc extinguishing chamber (810), a magnetic enhancement assembly (830) is arranged outside the slit assembly (820), the slit assembly (820) is composed of two oppositely arranged gas generating plates (821), and a slit is formed between the two gas generating plates (821) for the static contact (200) and the movable contact (100) to extend into.

7. The single-break high current miniature circuit breaker according to claim 6, characterized in that: A gas return slope (822) is arranged at the side of the gas generating plate (821) close to the inlet of the arc extinguishing chamber (810).

8. The single-break, high-current, miniature circuit breaker of claim 6, wherein: The arc extinguishing assembly (800) comprises an arc striking sheet (840), the arc striking sheet (840) has a first arc striking part (841) extending to the opening of the arc extinguishing chamber (810) or the side thereof and a second arc striking part (842) corresponding to the movable contact (100) at the breaking position.

9. The single-break, high-current, miniature circuit breaker of claim 4, wherein: The shell (400) inner wall corresponds to the outside of the static contact (200) and is provided with an arc baffle (410).

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