An overload current trip device for a circuit breaker

Abstract

The application discloses an overload current tripping device of a circuit breaker, which comprises a magnetic conducting frame, a triangular magnetic conducting block, a striking rod, a fixing plate, a compression spring, a position limiting sleeve and a trigger plate; the middle part of the magnetic conducting frame is provided with a rectangular opening for the copper bar of the circuit breaker to pass through; the top middle part of the magnetic conducting frame is provided with an inverted triangular opening for arranging the triangular magnetic conducting block; the fixing plate and the position limiting sleeve are arranged at the top end of the triangular magnetic conducting block and are used for limiting the triangular magnetic conducting block; the top end of the compression spring is fixed at the bottom end of the triangular magnetic conducting block, and the bottom end of the compression spring is fixed on the magnetic conducting frame; the top end of the striking rod is fixed on one side of the triangular magnetic conducting block; the trigger plate is a lever structure, one end of the trigger plate corresponds to the position of the bottom end of the striking rod, and the other end corresponds to the position of the tripping hook of the circuit breaker; the magnetic conducting frame and the triangular magnetic conducting block are made of paramagnetic materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of switching electrical appliances, in particular to an overload current tripping device of a circuit breaker. BACKGROUND

[0002] The circuit breaker refers to a switching device capable of closing, carrying and breaking the current under normal circuit conditions and capable of closing, carrying and breaking the current under abnormal circuit conditions within a specified time. In the rail transit traction power supply system, the circuit breaker is the guarantee for the safe operation of the power supply system. Under abnormal circuit conditions, the breaking time of the circuit breaker will directly affect the time for the traction power supply equipment to carry the fault current. In order to protect the safety of the power supply equipment under abnormal conditions, the circuit breaker needs to start the fast breaking response in a short time.

[0003] As a protection element of the power supply circuit, the circuit breaker itself is provided with multiple tripping devices, including a split excitation tripping device, an indirect tripping device, an under-voltage tripping device and an overload tripping device. Among them, the overload tripping device as a basic tripping device of the circuit breaker triggers the tripping device when the current value or the rising rate of the protected circuit exceeds the predetermined value, so as to realize the breaking operation of the circuit breaker. It is not constrained by the control circuit of the circuit breaker and is a device directly acting on the tripping. At present, in the direct current traction power supply system, the mainstream overload tripping device is affected by the disc spring variable stiffness characteristic, the motion structure and the setting current scale adjustment device, and the setting current value is extremely unstable, and the phenomenon of setting current value drift often occurs. SUMMARY

[0004] In order to solve the problems in the background art, the purpose of the present application is to provide an overload current tripping device of a circuit breaker.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] An overload current tripping device of a circuit breaker, comprising a magnetic conducting frame, a triangular magnetic conducting block, a striking rod, a fixed plate, a compression spring, a stop sleeve and a trigger plate.

[0007] The middle part of the magnetic conducting frame is provided with a rectangular opening for the current-carrying copper bar of the circuit breaker to pass through.

[0008] The top middle part of the magnetic conducting frame is provided with an inverted triangular opening for setting the triangular magnetic conducting block.

[0009] The fixed plate and the stop sleeve are arranged at the top end of the triangular magnetic conducting block, and the fixed plate and the stop sleeve are used for limiting the triangular magnetic conducting block.

[0010] The top end of the compression spring is fixed to the bottom end of the triangular magnetic conducting block, and the bottom end of the compression spring is fixed to the magnetic conducting frame.

[0011] The top end of the impact rod is fixedly arranged on one side of the triangular magnetic conductive block;

[0012] The trigger plate is a lever structure, and one end of the trigger plate corresponds to the position of the bottom end of the striker rod, and the other end corresponds to the position of the trip hook of the circuit breaker;

[0013] The magnetic conductive frame and the triangular magnetic conductive block are both made of paramagnetic materials.

[0014] In some embodiments, a current adjustment block is further included. A circular hole is provided on the side of the magnetic conductive frame for placing the current adjustment block. The current adjustment block is used to adjust the expected tripping current value of the circuit breaker.

[0015] In some embodiments, the invention further comprises a spring guide rod, a first linear bearing, a positioning slide rod, a second linear bearing and a positioning bent plate;

[0016] The spring guide rod and the positioning slide rod pass through the triangular magnetic conductive block, and the spring guide rod is located on the inner side of the compression spring, and the positioning slide rod and the impact rod are respectively located on two opposite sides of the triangular magnetic conductive block;

[0017] The triangular magnetic block is provided with a first linear bearing and a second linear bearing with a self-lubricating function, and the first linear bearing and the second linear bearing are slidably connected to the spring guide rod and the positioning slide rod respectively;

[0018] The positioning bent plate is fixed on the magnetic conductive frame. A positioning hole is formed on the positioning bent plate, and the impact rod passes through the positioning hole.

[0019] In some embodiments, a set current scale adjustment device is further included at the lower end of the magnetic conductive frame, which is used to set the initial compression amount of the compression spring.

[0020] In some embodiments, the set current scale adjustment device includes a threaded sleeve, a large bevel gear, a small bevel gear, a worm, a turbine and a dial;

[0021] The spring guide rod is provided with a thread and is connected to the threaded sleeve spiral pair;

[0022] The large bevel gear is connected to the threaded sleeve via a flat key;

[0023] The small bevel gear and the worm are fixedly connected together;

[0024] The small bevel gear and the large bevel gear are meshed with each other, and the turbine and the worm are meshed with each other;

[0025] The turbine is fixedly connected to the dial;

[0026] The worm is provided with a hexagonal square hole for matching with an external hexagonal wrench for user operation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The overload current tripping device of the circuit breaker provided by the present invention can quickly trip and open the circuit breaker when the loop current is abnormal, thereby ensuring the safety of the power supply equipment; and the compression spring is used as the reaction force mechanism, and its stiffness is stable, overcoming the influence of the variable stiffness characteristics of the disc spring; the triangular magnetic block has double guide rod limiters and is provided with self-lubricating bearings, which has smooth movement and stable structure; it solves the problem of drift of the set tripping current value of the mainstream overload tripping device in the DC traction power supply system; and the set current scale adjustment device adopts a bevel gear plus worm gear structure, and the worm gear has a self-locking characteristic, which can ensure the stability of the adjustment scale. At the same time, the scale adjustment tool adopts a universal external hexagonal wrench, which is easy to operate and highly reliable. The scale indication is easy to observe and read, which improves the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of an overload current tripping device for a circuit breaker provided by the present invention;

[0030] Figure 2 Schematic diagram of the principle of generating magnetic field in the magnetic frame and triangular magnetic blocks;

[0031] Figure 3 for Figure 1 Schematic diagram of the tripping principle of the overload current tripping device;

[0032] Figure 4 for Figure 1 A side cross-sectional view of the middle structure;

[0033] Figure 5 This is the installation diagram of the current scale adjustment device;

[0034] Figure 6 This is the main view of the current scale adjustment device;

[0035] Figure 7 It is a side view of the current scale adjustment device;

[0036] Figure 8 This is a schematic diagram of operation using a hexagonal wrench.

[0037] Description of reference numerals:

[0038] 1. Magnetic frame; 2. Triangular magnetic block; 3. Current adjustment block; 4. Impact rod; 5. Fixed plate; 6. Compression spring; 7. Set current scale adjustment device; 8. Spring guide rod; 9. Stop sleeve; 10. First linear bearing; 11. Positioning slide; 12. Second linear bearing; 13. Positioning bend plate; 14. Trigger plate; 15. Hexagonal wrench; 71. Threaded sleeve; 72. Large bevel gear; 73. Small bevel gear; 74. Worm; 75. Turbine; 76. Scale plate; I. Current-carrying copper busbar. DETAILED DESCRIPTION

[0039] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the following further describes how the present invention is implemented in conjunction with the accompanying drawings and specific implementation methods.

[0040] Reference Figures 1-4 As shown, the present invention provides an overload current tripping device for a circuit breaker, comprising a magnetic frame 1, a triangular magnetic block 2, a striking rod 4, a fixing plate 5, a compression spring 6, a stop sleeve 9 and a trigger plate 14. A rectangular opening is provided in the middle of the magnetic frame 1 for the passage of the current-carrying copper bar of the circuit breaker; an inverted triangular opening is provided in the middle of the top of the magnetic frame 1 for arranging the triangular magnetic block 2; the fixing plate 5 and the stop sleeve 9 are arranged at the top of the triangular magnetic block 2, and the fixing plate 5 and the stop sleeve 9 are used to limit the triangular magnetic block 2; the top end of the compression spring 6 is fixed to the bottom end of the triangular magnetic block 2, and the bottom end of the compression spring 6 is fixed to the magnetic frame 1; the top end of the striking rod 4 is fixedly arranged on one side of the triangular magnetic block 2; the trigger plate 14 is a lever structure, and one end of the trigger plate 14 corresponds to the position of the bottom end of the striking rod 4, and the other end corresponds to the position of the tripping hook of the circuit breaker; the magnetic frame 1 and the triangular magnetic block 2 are both made of paramagnetic material.

[0041] The working principle of the overload current tripping device of the circuit breaker provided by the present invention is as follows: because the magnetic frame 1 and the triangular magnetic block 2 are composed of paramagnetic materials, when the main circuit of the circuit breaker is energized, a magnetic field corresponding to the direction of the current will be generated along the magnetic frame 1 and the triangular magnetic block 2 around the current-carrying copper busbar. Under the action of the electromagnetic field, the magnetic frame 1 generates a downward electromagnetic force on the triangular magnetic block 2. When the current value or the rising rate in the current-carrying copper busbar exceeds a predetermined value, the generated electromagnetic attraction overcomes the spring resistance of the compression spring 6, forcing the triangular magnetic block 2 to move downward rapidly. The triangular magnetic block 2 is fixedly connected to the impact rod 4. The rapid movement of the triangular magnetic block 2 drives the impact rod 4 to quickly impact the trigger plate 14 downward. Figure 3As shown, the trigger plate 14 adopts a lever structure, and impacts the tripping hook of the circuit breaker by using the lever principle to realize the quick tripping and opening of the circuit breaker. The whole current loop is cut off, and then the triangular magnetic block 2 returns to the original position under the action of the spring force. The upper end of the triangular magnetic block 2 is provided with a fixed plate 5 and a stop sleeve 9 for limiting the triangular magnetic block. By setting stop sleeves 9 with different heights, the relative air gap between the triangular magnetic block 2 and the magnetic frame 1 can be changed to change the movement stroke of the triangular magnetic block.

[0042] Preferably, the overload current tripping device further comprises a current adjusting block 3. The side surface of the magnetic frame 1 is provided with a circular hole for placing the current adjusting block 3. The current adjusting block 3 is used to adjust the expected tripping current value of the circuit breaker. According to actual needs, the current adjusting block 3 can be added or removed. After the current adjusting block 3 is removed, the magnetic resistance of the whole magnetic loop increases, the magnetic induction intensity of the magnetic frame 1 decreases, the magnetic field force generated by the triangular magnetic block 2 becomes smaller, and a larger exciting current is required to overcome the resistance of the compression spring 6, so as to adjust the expected tripping current value of the circuit breaker.

[0043] Preferably, the overload current tripping device further comprises a spring guide rod 8, a first linear bearing 10, a positioning slide rod 11, a second linear bearing 12 and a positioning bent plate 13. The spring guide rod 8 and the positioning slide rod 11 pass through the triangular magnetic block 2, and the spring guide rod 8 is located on the inner side of the compression spring 6. The positioning slide rod 11 and the impact rod 4 are located on opposite sides of the triangular magnetic block 2, respectively. The triangular magnetic block 2 is provided with the first linear bearing 10 and the second linear bearing 12 with self-lubricating function. The first linear bearing 10 and the second linear bearing 12 are respectively connected with the spring guide rod 8 and the positioning slide rod 11 in sliding mode. The positioning bent plate 13 is fixed on the magnetic frame 1, and the positioning bent plate 13 is provided with a positioning hole, and the impact rod 4 passes through the positioning hole.

[0044] By setting the first linear bearing 10 and the second linear bearing 12, on the one hand, the up-and-down movement of the triangular magnetic block 2 is smooth and free of jamming, and on the other hand, the triangular magnetic block 2 is limited, which can ensure the stability of the position of the triangular magnetic block 2 and prevent displacement due to impact and vibration, so as to avoid the drift of the set tripping current value.

[0045] The adjustment mode of the above-mentioned scheme only has two modes of taking out or installing the current adjusting block 3, which belongs to stepwise adjustment. If the expected tripping current value of the circuit breaker needs to be finely adjusted, the compression amount of the compression spring 6 needs to be adjusted. For further reference Figures 5-8Preferably, the overload current tripping device further includes a set current scale adjustment device 7 disposed at the lower end of the magnetic conductive frame 1, for setting the initial compression of the compression spring 6. The greater the initial compression of the compression spring 6, the greater the resistance exerted by the compression spring 6 on the triangular magnetic conductive block 2, the greater the surge current required to overcome the spring resistance, and the greater the expected tripping current value of the circuit breaker.

[0046] Preferably, the set current scale adjustment device 7 includes a threaded sleeve 71, a large bevel gear 72, a small bevel gear 73, a worm 74, a turbine 75 and a dial 76; the spring guide rod 8 is provided with a thread and is spirally connected to the threaded sleeve 71; the large bevel gear 72 is connected to the threaded sleeve 71 through a flat key; the small bevel gear 73 and the worm 74 are fixed together; the small bevel gear 73 and the large bevel gear 72 are meshed with each other, and the turbine 75 and the worm 74 are meshed with each other; the turbine 75 and the dial 76 are fixed together; the worm 74 is provided with a hexagonal square hole for cooperating with an external hexagonal wrench 15 for user operation.

[0047] The operating principle during user operation is as follows: worm 74 is provided with a hexagonal square hole. Operating an external hexagonal wrench 15 rotates worm 74, which in turn drives small bevel gear 73. This meshes with large bevel gear 72, driving threaded sleeve 71 to spiral upward or downward along the axial direction of spring guide rod 8. The upward and downward spiral motion of threaded sleeve 71 compresses compression spring 6 to varying degrees, and the resistance exerted by compression spring 6 on triangular magnetic block 2 also varies accordingly. Simultaneously, as worm 74 rotates, worm gear 75 also meshes with the dial 76. This meshing of the worm gear corresponds to different indicator scales. This indicator scale is correlated with the spring compression and the expected trip current value of the circuit breaker. By recording the indicator scale at a given spring compression and determining the circuit breaker trip current value at that state through setting tests, the scale value corresponding to that expected trip current can be determined. If the user requires a different expected trip current value based on the actual circuit breaker operation, they simply adjust the scale to the position corresponding to the expected trip current. In particular, the worm gear has a self-locking function, making this circuit breaker set current scale adjustment device structurally stable and immune to vibration and displacement caused by impact during circuit breaker opening and closing operations.

[0048] In summary, the overload current tripping device of the circuit breaker provided by the present invention can quickly trip and open the circuit breaker when the loop current is abnormal, thereby ensuring the safety of the power supply equipment; and the compression spring is used as the reaction force mechanism, and its stiffness is stable, overcoming the influence of the variable stiffness characteristics of the disc spring; the triangular magnetic block has double guide rod limiters and is provided with self-lubricating bearings, which have smooth movement and stable structure; it solves the problem of drift of the set tripping current value of the mainstream overload tripping device in the DC traction power supply system; and the set current scale adjustment device adopts a bevel gear plus worm gear structure, and the worm gear has a self-locking characteristic, which can ensure the stability of the adjustment scale. At the same time, the scale adjustment tool adopts a universal external hexagonal wrench, which is easy to operate and highly reliable. The scale indication is easy to observe and read, which improves the user experience.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be covered by the scope of the claims of the present invention.

Claims

1. An overload current tripping device for a circuit breaker, characterized in that: It comprises a magnetic conductive frame (1), a triangular magnetic conductive block (2), an impact rod (4), a fixing plate (5), a compression spring (6), a stop sleeve (9) and a trigger plate (14); A rectangular opening is provided in the middle of the magnetic conductive frame (1) for allowing the current-carrying copper busbar of the circuit breaker to pass through; An inverted triangular opening is provided in the middle of the top of the magnetic conductive frame (1) for arranging the triangular magnetic conductive block (2); The fixing plate (5) and the stop sleeve (9) are arranged at the top end of the triangular magnetic conductive block (2), and the fixing plate (5) and the stop sleeve (9) are used to limit the triangular magnetic conductive block (2); The top end of the compression spring (6) is fixed to the bottom end of the triangular magnetic conductive block (2), and the bottom end of the compression spring (6) is fixed to the magnetic conductive frame (1); The top end of the impact rod (4) is fixedly arranged on one side of the triangular magnetic conductive block (2); The trigger plate (14) is a lever structure, and one end of the trigger plate (14) corresponds to the position of the bottom end of the impact rod (4), and the other end corresponds to the position of the tripping hook of the circuit breaker; The magnetic conductive frame (1) and the triangular magnetic conductive block (2) are both made of paramagnetic materials; It also includes a spring guide rod (8), the spring guide rod (8) passes through the triangular magnetic block (2), and the spring guide rod (8) is located on the inner side of the compression spring (6); It also includes a set current scale adjustment device (7) arranged at the lower end of the magnetic conductive frame (1) and used to set the initial compression amount of the compression spring (6); The set current scale adjustment device (7) comprises a threaded sleeve (71), a large bevel gear (72), a small bevel gear (73), a worm (74), a turbine (75) and a scale plate (76); The spring guide rod (8) is provided with a thread and is connected to the threaded sleeve (71) in a spiral pair; The large bevel gear (72) is connected to the threaded sleeve (71) via a flat key; The small bevel gear (73) and the worm (74) are fixedly connected together; The small bevel gear (73) and the large bevel gear (72) are meshed with each other, and the turbine (75) and the worm (74) are meshed with each other; The turbine (75) is fixedly connected to the dial (76); The worm (74) is provided with a hexagonal square hole for cooperating with an external hexagonal wrench (15) for user operation.

2. The overload current tripping device of the circuit breaker according to claim 1, characterized in that: It also includes a current adjustment block (3), and a circular hole is provided on the side of the magnetic conductive frame (1) for placing the current adjustment block (3); the current adjustment block (3) is used to adjust the size of the expected tripping current value of the circuit breaker.

3. The overload current tripping device of the circuit breaker according to claim 1, characterized in that: It also includes a first linear bearing (10), a positioning slide rod (11), a second linear bearing (12) and a positioning bent plate (13); The positioning slide bar (11) passes through the triangular magnetic conductive block (2), and the positioning slide bar (11) and the impact bar (4) are respectively located on two opposite sides of the triangular magnetic conductive block (2); The triangular magnetic block (2) is provided with a first linear bearing (10) and a second linear bearing (12) with a self-lubricating function, and the first linear bearing (10) and the second linear bearing (12) are respectively slidably connected to the spring guide rod (8) and the positioning slide rod (11); The positioning bent plate (13) is fixed on the magnetic conductive frame (1), a positioning hole is provided on the positioning bent plate (13), and the impact rod (4) passes through the positioning hole.

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