Circuit breaker with mechanical short-circuit short-time function

Abstract

The application relates to a circuit breaker with a mechanical short-circuit short-time delay function, belonging to the technical field of switching electrical apparatuses. The circuit breaker comprises a circuit breaker body, a transmission mechanism arranged on the circuit breaker body and an operating mechanism, and is characterized in that a mechanical short-circuit short-time delay release is further arranged on the circuit breaker body and connected with the transmission mechanism; when the short-circuit current is greater than the setting current value of the mechanical short-circuit short-time delay release, the transmission mechanism is pulled by the mechanical short-circuit short-time delay release in a delayed manner; when the short-circuit current disappears, the transmission mechanism is instantaneously reset; if the short-circuit current does not disappear within a certain time, the operating mechanism is tripped by the mechanical short-circuit short-time delay release through the transmission mechanism. Advantages: when the short-circuit current is greater than the setting current value of the mechanical short-circuit short-time delay release, the mechanical short-circuit short-time delay release is instantaneously attracted and the action speed is slowed down by the action of the related components of the structural system, so that the short-circuit short-time delay function of the direct-current circuit breaker is realized in the absence of an auxiliary power supply through a simple and reliable mode.

Description

Technical Field

[0001] This invention belongs to the field of switching electrical equipment technology, and specifically relates to a circuit breaker with mechanical short-circuit short-delay function. Background Technology

[0002] The aforementioned short-circuit short-delay function refers to the circuit breaker's ability to delay the circuit for a certain period of time (e.g., 0.1–0.5 seconds) before disconnecting it after detecting a short-circuit fault current. Because this type of circuit breaker is widely used in DC power grids such as photovoltaic, energy storage, and rail transit, it is called a DC circuit breaker based on its structure and operating mechanism. When a fault current, such as that caused by overload or short circuit, occurs in the circuit, it can disconnect the protected circuit and electrical facilities. To meet the requirements of selective protection (i.e., graded protection) in the power supply system, the upstream circuit breaker usually needs to have a short-circuit short-delay function. This is because when a short circuit occurs downstream in the distribution system, the short-circuit current will flow through both the upstream and downstream circuit breakers simultaneously. If both circuit breakers operate instantaneously, the upstream circuit breaker may trip first, resulting in a cascading trip and expanding the power outage area. The aforementioned short-circuit short-delay function is generally achieved through an intelligent trip unit. However, since DC intelligent trip units cannot achieve self-powering through current transformers like AC intelligent trip units, they require an auxiliary power supply, typically 24V or 48V DC, to operate. When the auxiliary power supply is unstable, the DC intelligent trip unit will malfunction, causing the circuit breaker's short-circuit protection function to fail. This is because the core functions of the intelligent trip unit, such as detection, logic judgment, and trip control, all require electrical drive. Summary of the Invention

[0003] The objective of this invention is to provide a circuit breaker with a mechanical short-circuit short-delay function that helps to free the DC intelligent trip unit from dependence on auxiliary power supply, thereby meeting the selective protection requirements of the power system and allowing for convenient adjustment of the short-delay time.

[0004] The present invention achieves its objective by providing a circuit breaker with a mechanical short-circuit short-delay function, comprising a circuit breaker body, a transmission mechanism disposed on the circuit breaker body, and an operating mechanism. The invention is characterized by further comprising a mechanical short-circuit short-delay trip unit, which is disposed on the circuit breaker body and connected to the transmission mechanism. When the short-circuit current exceeds the set current value of the mechanical short-circuit short-delay trip unit, the mechanical short-circuit short-delay trip unit activates the transmission mechanism with a delay. When the short-circuit current disappears, the transmission mechanism instantly resets. If the short-circuit current does not disappear within a certain time, the mechanical short-circuit short-delay trip unit, through the transmission mechanism, trips the operating mechanism.

[0005] In a specific embodiment of the present invention, the circuit breaker further includes a conductive busbar, and the mechanical short-circuit short-delay trip unit is located between the circuit breaker body and the conductive busbar.

[0006] In another specific embodiment of the present invention, the mechanical short-circuit short-delay trip unit includes a magnetic yoke, an armature, an energy storage spring, a momentary spring, a lever, an escapement, a ratchet, a double-layer gear, a pull rod, a rack, a single gear, and a guide post. The magnetic yoke is fixed to a magnetic yoke fixing plate, which is fixed to the circuit breaker body. An armature limiting b is fixed at the upper part of the magnetic yoke and at a position corresponding to the armature. The conductive bus passes through the magnetic yoke. The momentary spring is sleeved on the guide post. The upper end of the momentary spring b is supported on a momentary spring force adjusting nut screwed onto the guide post, while the lower end is supported on a momentary spring support seat that is loosely sleeved on the guide post and fixed to the front side of the magnetic yoke fixing plate. The armature is threadedly fixed to the guide post. Under the action of spring force, the armature moves upward, and under the limitation of the armature limiting baffle, an air gap is formed between the magnetic yoke and the armature. The energy storage spring is sleeved on the guide post at a position below the instantaneous spring support seat. The upper end of the energy storage spring is supported on the guide post boss formed on the guide post, and the lower end is supported on the pivot seat. The middle part of the pivot seat is sleeved on the guide post and corresponds to the left end of the lever cavity of the lever. The front end and rear end of the pivot seat are each pivotally connected to the lever front and rear plates of the same shape and size that form the lever cavity through a bearing. The lower middle part of the lever is hinged to the magnetic yoke fixing plate through the lever pivot. A lever front and rear plate is fixed between the upper middle positions of the lever front and rear plates that form the lever cavity. A support shaft is provided, with a magnetic yoke fixing plate gear guard fixed to the upper right front side of the magnetic yoke fixing plate. The space between the magnetic yoke fixing plate gear guard and the magnetic yoke fixing plate forms a lever movement space. The escapement is rotatably mounted in the lever movement space between the magnetic yoke fixing plate and the magnetic yoke fixing plate gear guard on opposite sides via the escapement pivot shaft. The right end of the escapement engages with a ratchet, and when the ratchet rotates, the ratchet teeth collide with the escapement fork, causing the escapement to swing. Each swing of the escapement disengages one ratchet tooth. The ratchet is fixed to a pinion and rotatably mounted on a ratchet shaft, which is fixed between the magnetic yoke fixing plate and the magnetic yoke fixing plate gear guard. The double-layer gear... The device includes a double-layered gear large gear and a double-layered gear small gear. The small gear meshes with the double-layered gear large gear. The front side of the double-layered gear large gear is fixed to the double-layered gear small gear. The small gear, along with the double-layered gear large gear, is rotatably mounted between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate via a double-layered gear shaft. The small gear meshes with a single gear, which is rotatably mounted on a single gear shaft fixed between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate on opposite sides. A rack is fixed to the middle of the pull rod and meshes with the single gear. The left end of the pull rod extends into the pull rod cavity and is connected to the front and rear plate support shaft of the lever in a state corresponding to the middle of the front and rear plate support shaft of the lever.The middle part of the pull rod is positioned laterally between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate, while the right end of the pull rod extends to the right side between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate and connects to the transmission mechanism.

[0007] In another specific embodiment of the present invention, a first guide roller pair and a second guide roller pair of the middle section of the pull rod are provided between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate, and in the middle region corresponding to the length direction of the pull rod. The second guide roller pair of the middle section of the pull rod is located to the right of the first guide roller pair of the middle section of the pull rod and there are two sets of them. The middle section of the pull rod is located between the first guide roller pair and the second guide roller pair of the middle section of the pull rod and simultaneously forms a sliding pair that slides left and right with the first guide roller pair and the second guide roller pair of the middle section of the pull rod. Each of the first guide roller pairs of the middle section of the pull rod is rotatably disposed in the middle of the shaft of the first guide roller pair of the middle section of the pull rod, and each of the second guide roller pairs of the middle section of the pull rod is rotatably disposed on the shaft of the second guide roller pair of the middle section of the pull rod. The shafts of the first guide roller pair and the second guide roller pair of the middle section of the pull rod are fixed between the magnetic yoke fixing plate and the gear guard plate of the magnetic yoke fixing plate.

[0008] In another specific embodiment of the present invention, the magnetic yoke fixing plate gear guard plate is fixed to the front side of the magnetic yoke fixing plate by a set of spaced-apart suspended studs, and the set of spaced-apart suspended studs forms the pull rod movement space between the magnetic yoke fixing plate and the magnetic yoke fixing plate gear guard plate.

[0009] In another specific embodiment of the present invention, a pull rod drive connection boss is formed on the front side of the right end of the pull rod, and the pull rod drive connection boss is connected to the transmission mechanism; the armature is instantly attracted and drives the escapement in sequence through the guide post, lever, pull rod, rack, single gear, double-layer gear small gear, double-layer gear large gear, small gear, and ratchet, and the escapement slows down the action speed of the transmission mechanism by the restraining effect of the escapement.

[0010] In a further specific embodiment of the present invention, the transmission mechanism includes a transmission arm, and a transmission arm pull rod mating groove is formed at one end of the transmission arm facing the pull rod. The pull rod transmission connecting boss on the front side of the right end of the pull rod is connected to the transmission arm at a position corresponding to the transmission arm pull rod mating groove. When the armature is momentarily attracted and pulls the escapement, the action speed of the transmission arm is slowed down by the restraining effect of the escapement. When the short-circuit current disappears, the transmission arm is momentarily reset under the action of the reaction spring.

[0011] In a further specific embodiment of the present invention, the magnetic yoke and the armature constitute an electromagnetic trip device, and when a fault current occurs in the circuit, the current through the conductive bus increases, the electromagnetic force between the magnetic yoke and the armature increases, and under the condition of forming an air gap between the magnetic yoke and the armature, the armature overcomes the reaction force of the instantaneous spring and moves downward and attracts the magnetic yoke.

[0012] In yet another specific embodiment of the present invention, a lever guard plate is fixed to the front side of the magnetic yoke fixing plate and at a position corresponding to the front of the lever by a set of spaced-apart freewheeling bolts. The lower center of the lever guard plate extends toward the armature to protect the armature. The space between the lever guard plate and the magnetic yoke fixing plate constitutes the lever movement space. The magnetic yoke fixing plate and the lever guard plate are made of non-magnetic materials to avoid short circuits in the magnetic circuit between the magnetic yoke and the armature. The non-magnetic material is stainless steel or copper. The copper is brass.

[0013] In yet another specific embodiment of the invention, the yoke is fixed to the front side of the yoke fixing plate by means of a yoke limiting plate screw, and the lower edge of the gear guard plate of the yoke fixing plate is supported on the upper surface of the right end of the yoke limiting plate; the short delay action time and return time can be changed by changing the number of teeth and idle stroke ratio of the rack, the tooth ratio between the double-layer gear and the single gear and pinion, and the mass of the escapement.

[0014] The technical effect of the technical solution provided by the present invention is as follows: due to the addition of a mechanical short-circuit short-delay trip unit, when the short-circuit current is greater than the set current value of the mechanical short-circuit short-delay trip unit, the mechanical short-circuit short-delay trip unit will be instantly engaged and the action speed will be slowed down by the action of the relevant components of its structural system. In a simple and reliable way, the DC circuit breaker can realize the short-circuit short-delay function without auxiliary power supply. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram for rear view; Figure 3 for Figure 1 The diagram shows the external shape of the mechanical short-circuit short-delay trip mechanism; Figure 3a To remove Figure 3 A schematic diagram showing the lever guard plate, magnetic yoke fixing plate, and gear guard plate as viewed from behind; Figure 4 To remove Figure 3 The diagram shows the three-dimensional structure of the lever guard plate, magnetic yoke fixing plate, and gear guard plate shown. Figure 5 for Figure 1 A schematic diagram of the first embodiment of the armature of the mechanical short-circuit short-delay trip unit is shown; Figure 6 for Figure 1 A schematic diagram of the second embodiment of the armature of the mechanical short-circuit short-delay trip unit is shown; Figure 7 for Figure 1 A schematic diagram of the third embodiment of the armature of the mechanical short-circuit short-delay trip unit is shown; Figure 8 for Figure 3a and Figure 4 The diagram shows the escapement engaging with the ratchet.

[0016] In the diagram: 1. Circuit breaker body; 2. Transmission mechanism; 21. Transmission arm; 211. Transmission arm pull rod mating groove; 3. Mechanical short-circuit short-delay trip unit; 31. Magnetic yoke; 311. Magnetic yoke fixing plate; 3111. Magnetic yoke fixing plate gear guard plate; 3112. Pull rod movement space; 31111. Elevation stud; 312. Armature limit baffle; 313. Lever guard plate; 3131. Elevation bolt; 3132. Lever movement space; 314. Magnetic yoke limiting plate; 3141. Magnetic yoke limiting plate screw; 32. Armature; 321. Air gap; 33a. Energy storage spring; 33b. Instantaneous spring; 34. Lever; 341. Pivot seat; 3411. Bearing; 342. Lever cavity; 343. Lever shaft; 344. Lever front and rear plate support shaft; 35. 351. Escapement pivot shaft; 352. Escape fork; 36a. Ratchet; 36b. Double-layer gear; 36c. Single gear; 36d. Ratchet tooth; 36e. Pinion; 36f. Ratchet shaft; 36g. Double-layer gear shaft; 36i. Single gear shaft; 36j. Double-layer gear large gear; 36k. Double-layer gear small gear; 37. Lever; 371. First guide roller pair in the middle of the lever; 3711. Shaft of the first guide roller pair in the middle of the lever; 372. Second guide roller pair in the middle of the lever; 3721. Shaft of the second guide roller pair in the middle of the lever; 373. Lever drive connecting boss; 38. Rack; 39. Guide post; 391. Instantaneous spring force adjusting nut; 392. Instantaneous spring support; 393. 4. Guide post boss; 5. Conductive busbar; 6. Operating mechanism; 7. Tripping plate. Detailed Implementation

[0017] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without some of these specific details. The description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. Well-known structures and techniques are not shown in the drawings and the following description in order to avoid unnecessarily obscuring the invention; and for clarity, the thickness of regions and layers may be exaggerated. The same reference numerals in the figures denote the same or similar structures, and therefore their detailed description will be omitted. Furthermore, the features, structures, or characteristics described below may be combined in any suitable manner in one or more embodiments. And, the directional terms appearing in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the circuit breaker of the present invention.

[0018] Please see Figure 1 and Figure 2 The diagram shows the circuit breaker body 1, the transmission mechanism 2 mounted on the circuit breaker body 1, and the operating mechanism 5.

[0019] The key technical point of the technical solution provided by this invention is that it also includes a mechanical short-circuit short-delay trip unit 3. This mechanical short-circuit short-delay trip unit 3 is mounted on the circuit breaker body 1 and connected to the aforementioned transmission mechanism 2. When the short-circuit current exceeds the set current value of the mechanical short-circuit short-delay trip unit 3, the mechanical short-circuit short-delay trip unit 3 will pull the transmission mechanism 2 after a delay. When the short-circuit current suddenly disappears, the transmission mechanism 2 instantly resets under the action of the return spring. If the short-circuit current does not disappear within a certain time, the mechanical short-circuit short-delay trip unit 3 will trip the operating mechanism 5 through the transmission mechanism 2. In this embodiment, the delay time for pulling the transmission mechanism 2 is 0.1-0.5 seconds; the aforementioned "certain time if the short-circuit current does not disappear within a certain time" is also 0.1-0.5 seconds.

[0020] exist Figure 2 The diagram also shows a trip plate 51 mounted on the operating mechanism 5. In the event of a short circuit, the armature 32 of the mechanical short-circuit short-delay trip unit 3, which will be described in detail below, is instantly attracted by electromagnetic force. The action is transmitted to the trip plate 51 through the transmission mechanism 2, thereby causing the operating mechanism 5 to trip and the circuit breaker to finally open and cut off the fault current caused by the short circuit.

[0021] Depend on Figure 1 As shown, the aforementioned circuit breaker also includes a conductor bar 4, and the aforementioned mechanical short-circuit short-delay trip unit 3 is located between the aforementioned circuit breaker body 1 and the conductor bar 4.

[0022] Please pay attention. Figure 3 , Figure 3a as well as Figure 4 And combined Figure 1 The preferred, but not absolutely limited, structure of the aforementioned mechanical short-circuit short-delay trip unit 3 is as follows: It includes a magnetic yoke 31, an armature 32, an energy storage spring 33a, an instantaneous spring 33b, a lever 34, an escapement 35, a ratchet 36a, a double-layer gear 36b, a pull rod 37, a rack 38, a single gear 36c, and a guide post 39. The magnetic yoke 31 is fixed to the magnetic yoke fixing plate 311, i.e., fixed to the front side of the magnetic yoke fixing plate 311, which is fixed to the aforementioned circuit breaker body 1. Figure 1 As shown), an armature limiting baffle 312 is fixed on the upper part of the magnetic yoke 31 at a position corresponding to the aforementioned armature 32. Figure 1The conductive busbar 4, as shown, passes through the magnetic yoke 31. A momentary spring 33b is fitted onto the guide post 39. The upper end of the momentary spring 33b is supported on a momentary spring force adjusting nut 391 screwed onto the guide post 39, while the lower end is supported on a momentary spring support seat 392, which is loosely fitted onto the guide post 39 and fixed to the front side of the aforementioned magnetic yoke fixing plate 311. The armature 32 is threadedly fixed to the guide post 39. Under the spring force of the momentary spring 33b, the armature 32 displaces upward, and under the limitation of the aforementioned armature limiting baffle 312, an air gap 321 is formed between the magnetic yoke 31 and the armature 32. The energy storage spring 33a is fitted onto the guide post 39 at a position below the aforementioned momentary spring support seat 392. The upper end of the spring 33a is supported on the guide post boss 393 formed on the guide post 39, and the lower end is supported on the pivot seat 341. The middle part of the pivot seat 341 is sleeved on the guide post 39 and corresponds to the left end of the lever cavity 342 of the lever 34. The front end and rear end of the pivot seat 341 are pivotally connected to the lever front and rear plates of the same shape and size that form the lever cavity 342 through a bearing 3411. The lower middle part of the lever 34 is hinged to the magnetic yoke fixing plate 311 through the lever pivot 343. A lever front and rear plate support shaft 344 is fixed between the upper center of the lever front and rear plates that form the lever cavity 342. A magnetic yoke fixing plate tooth is fixed on the upper right front side of the magnetic yoke fixing plate 311. The space between the yoke fixing plate 3111 and the gear guard plate 3111 forms a lever movement space 3112. The escapement 35 is rotatably disposed within the aforementioned lever movement space 3112 between the opposing sides of the yoke fixing plate 3111 and the gear guard plate 3111 via the escapement pivot 351. The right end of the escapement 35 engages with the ratchet 36a. When the ratchet 36a rotates, the ratchet teeth 36d of the ratchet 36a collide with the escape fork 352 of the escapement 35, causing the escapement 35 to swing. Each swing of the escapement 35 disengages one ratchet tooth 36d. The ratchet 36a is fixed to the pinion 36e and rotates via the pinion 36e together with the ratchet 36a. The aforementioned double-layer gear 36b is mounted on a ratchet shaft 36f, which is fixed between the aforementioned magnetic yoke fixing plate 311 and the magnetic yoke fixing plate gear guard plate 3111. The aforementioned double-layer gear 36b includes a double-layer gear large gear 36j and a double-layer gear small gear 36k. The aforementioned small gear 36e meshes with the double-layer gear large gear 36j. The front side of the double-layer gear large gear 36j is fixed to the double-layer gear small gear 36k. The double-layer gear small gear 36k, along with the double-layer gear large gear 36j, is rotatably mounted between the magnetic yoke fixing plate 311 and the magnetic yoke fixing plate gear guard plate 3111 via the double-layer gear shaft 36g. The double-layer gear small gear 36k meshes with the aforementioned single gear 36c, which is rotatably mounted on a single gear shaft 36i.The single gear shaft 36i is fixed between the magnetic yoke fixing plate 311 and the gear guard plate 3111 on opposite sides. The rack 38 is fixed to the middle of the pull rod 37 and meshes with the aforementioned single gear 36c. During the leftward movement of the rack 38, the single gear 36c rotates to the toothless portion of the rack 38 (i.e., the toothless portion). At this time, the restraining effect of the escapement 35 disappears. The left end of the pull rod 37 extends into the aforementioned pull rod cavity 342 and connects to the lever front and rear plate support shaft 344 in the middle position corresponding to the aforementioned lever front and rear plate support shaft 344. The middle part of the pull rod 37 moves left and right between the aforementioned magnetic yoke fixing plate 311 and the gear guard plate 3111, i.e., within the aforementioned pull rod movement space 3112. The right end of the pull rod 37 extends to the right side between the magnetic yoke fixing plate 311 and the gear guard plate 3111 and connects to the aforementioned transmission mechanism 2.

[0023] See you later Figure 3 , Figure 3a and Figure 4 Between the aforementioned magnetic yoke fixing plate 311 and the magnetic yoke fixing plate gear guard plate 3111, and in the middle region corresponding to the length direction of the aforementioned pull rod 37, there are two pairs of pull rod middle guide rollers 371 and pull rod middle guide rollers 372, which are vertically aligned with each other. The pull rod middle guide rollers 372 are located to the right of the pull rod middle guide rollers 371 and there are two sets (also referred to as "two pairs"). The middle part of the pull rod 37 is located between the pull rod middle first guide rollers 371 and the pull rod middle second guide rollers 372 and is simultaneously connected to the pull rod. The first guide roller pair 371 in the middle and the second guide roller pair 372 in the middle of the pull rod form a sliding pair that slides left and right. The first guide roller pair 371 in the middle of the pull rod is rotatably mounted on the middle of the shaft 3711 of the first guide roller pair in the middle of the pull rod, while the second guide roller pair 372 in the middle of the pull rod is rotatably mounted on the shaft 3721 of the second guide roller pair in the middle of the pull rod. The aforementioned first guide roller pair shaft 3711 and second guide roller pair shaft 3721 in the middle of the pull rod are fixed between the aforementioned magnetic yoke fixing plate 311 and the aforementioned magnetic yoke fixing plate gear guard plate 3111. Due to the structure of the magnetic yoke 31 and the armature 32, when a short circuit occurs, the current flowing through the conductive busbar 4 increases, and the electromagnetic force between the magnetic yoke 31 and the armature 32 increases. Since there is the aforementioned air gap 321 between the magnetic yoke 31 and the armature 32, the armature 32 will overcome the reaction force of the instantaneous spring 33b and move downward to engage with the magnetic yoke 31.

[0024] The aforementioned magnetic yoke fixing plate gear guard plate 3111 is fixed to the front side of the aforementioned magnetic yoke fixing plate 311 by a set of spaced-apart suspended studs 31111. The aforementioned pull rod movement space 3112 is formed between the aforementioned magnetic yoke fixing plate 311 and the magnetic yoke fixing plate gear guard plate 3111 by the set of spaced-apart suspended studs 31111.

[0025] A pull rod drive connection boss 373 is formed on the front side of the right end of the aforementioned pull rod 37. The pull rod drive connection boss 373 is connected to the aforementioned transmission mechanism 2. The aforementioned armature 32 is instantly attracted and drives the aforementioned escapement 35 in sequence through the aforementioned guide post 39, lever 34, pull rod 37, rack 38, single gear 36c, double-layer gear 36b's double-layer gear pinion 36k, double-layer gear 36b's double-layer gear large gear 36j, pinion 36e, and ratchet 36a. The escapement 35 slows down the operation speed of the aforementioned transmission mechanism 2 due to its restraining effect.

[0026] The aforementioned transmission mechanism 2 includes a transmission arm 21. A transmission arm pull rod mating groove 211 is formed at one end of the transmission arm 21 facing the aforementioned pull rod 37. The aforementioned pull rod transmission connecting boss 373 on the right front side of the aforementioned pull rod 37 is connected to the transmission arm 21 at the position corresponding to the transmission arm pull rod mating groove 211. When the aforementioned armature 32 is instantly attracted and pulls the aforementioned escapement 35, the action speed of the aforementioned transmission arm 21 is slowed down by the restraining effect of the escapement 35. When the short circuit current disappears, the transmission arm 21 is instantly reset under the action of the reaction spring.

[0027] The aforementioned magnetic yoke 31 and armature 32 constitute an electromagnetic trip unit. In other words, the mechanical short-circuit short-delay trip unit of the present invention is an electromagnetic trip unit. When a fault current occurs in the circuit, the current through the aforementioned conductive busbar 4 increases, and the electromagnetic force between the magnetic yoke 31 and armature 32 increases. Under the condition of forming an air gap 321 between the magnetic yoke 31 and armature 32, the armature 32 overcomes the reaction force of the aforementioned instantaneous spring 33b and moves downward and attracts the magnetic yoke 31.

[0028] A lever guard plate 313 is fixed to the front side of the aforementioned magnetic yoke fixing plate 311 and at a position corresponding to the front of the aforementioned lever 34 by a set of spaced-apart free-floating bolts 3131. The lower center of the lever guard plate 313 extends toward the aforementioned armature 32 to protect the armature 32. The space between the lever guard plate 313 and the aforementioned magnetic yoke fixing plate 311 constitutes the lever movement space 3132. The aforementioned magnetic yoke fixing plate 311 and the aforementioned lever guard plate 313 are non-magnetic materials to avoid short circuits in the magnetic circuit between the magnetic yoke 31 and the armature 32. In this embodiment, the aforementioned non-magnetic material is stainless steel, but it can also be copper or other equivalent materials. The aforementioned copper is preferably brass.

[0029] The aforementioned magnetic yoke 31 is fixed to the front side of the aforementioned magnetic yoke fixing plate 311 by means of magnetic yoke limiting plate screws 3141. The lower edge of the aforementioned magnetic yoke fixing plate gear guard plate 3111 is supported on the upper right surface of the magnetic yoke limiting plate 314. By changing the number of teeth and idle stroke ratio of the aforementioned rack 38, the tooth ratio between the aforementioned double-layer gear 36b and the single gear 36c and pinion 36e, and the mass of the aforementioned escapement 35, the short delay action time and return time can be changed.

[0030] Applicant combined Figures 1 to 4 Briefly describe the working principle of the mechanical short-circuit short-delay trip unit 3. Since the mechanical short-circuit short-delay trip unit 3 is installed between the conductor bus 4 and the circuit breaker body 1, the conductor bus 4 passes through the magnetic yoke 31 in the mechanical short-circuit short-delay trip unit 3, and thus the current also passes through (i.e. flows through) the magnetic yoke 31. When the short-circuit current is greater than the set current value of the mechanical short-circuit short-delay trip unit 3, the electromagnetic force between the magnetic yoke 31 and the armature 32 is greater than the reaction force of the instantaneous spring 33b. Due to the air gap 321 between the magnetic yoke 31 and the armature 32, the armature 32 will move downward and attract the magnetic yoke 31. The guide post 39, fixed to the armature 32, also moves downward and compresses the energy storage spring 33a, preferably a compression spring, tension spring, or other type of component with energy storage and release functions. The energy storage spring 33a applies spring force to the pivot seat 341, which drives the lever 34 to begin rotating around the lever axis 343. At the same time, the lever front and rear plate support shaft 344 on the lever 34 pulls the pull rod 37 to the left. The rack 38 on the pull rod 37 drives multiple gear sets, ultimately causing the ratchet 36a to accelerate. Each ratchet tooth 36d on the ratchet 36a continuously collides with the two escape forks 352 on the escapement 35, causing the escapement 35 to swing back and forth, thus creating a restraining effect and significantly slowing down the action speed of the pull rod 37. If the short-circuit current disappears at this time, the armature 32 resets under the action of the spring, the pull rod 37 no longer moves to the left, and the operating mechanism 5 will not trip. In this way, the circuit breaker achieves non-tripping within the return time and can return. If the short-circuit current does not disappear, after the return time has elapsed, when the single gear 36c rotates to the toothless part of the rack 38, the restraining effect of the escapement 35 disappears, and the pull rod 37 moves quickly under the elastic force of the energy storage spring 33a, pulling the transmission mechanism 2, forcing the trip plate 51 to move, thereby disengaging the operating mechanism 5. This achieves the short-delay action of the circuit breaker.

[0031] Please see Figure 5 , Figure 5 This is a schematic diagram of the instantaneous electromagnet structure in the mechanical short-circuit short-delay trip unit 3. Since the short-circuit short-delay setting current is usually relatively small, the armature 32 is preferably designed as a V-shaped structure (more precisely, a trapezoidal structure). In this structure, the magnetic yoke 31 is subjected to a larger electromagnetic force, which can more reliably drive the delay mechanism to operate.

[0032] Please see Figure 6 and Figure 7 As another implementation, the aforementioned instantaneous electromagnet, i.e., the aforementioned magnet 32, can also be designed in other forms, such as: push-pull type ( Figure 6 ), and matching ( Figure 7 )wait.

[0033] Please see Figure 8 The applicant provides the following explanation regarding the changes in the short delay action time and return time mentioned above, which are achieved by altering the number of teeth and idle stroke ratio of rack 38, the tooth ratio between double-layer gear 36b and single gear 36c and pinion 36e, and the mass of escapement 35. Figure 8 This diagram illustrates the interaction between the escapement 35 and the ratchet 36a. The mechanical short-circuit short-delay release 3, through the rotation of its ratchet 36a, causes the escapement 335 to reciprocate, generating a restraining effect and ultimately achieving a delayed action. According to Formula 1 below, the delay time is related to the number of teeth n, the moment of inertia J of the escapement 35, the swing angle θ of the escapement 35, and the average torque M of the escapement 35. The delay time and return time can be adjusted by modifying the ratio of the number of teeth on the rack 38 to the idle stroke in the mechanical short-circuit short-delay release 3, the tooth ratio between the double-layer gear 36b and the single gear 36c and pinion 36e, and the mass of the escapement 35.

[0034]

[0035] Where: t—delay time n—Number of teeth rotating in the escapement J—Moment of inertia of the escapement θ — escapement oscillation angle M—Average torque on the escapement In summary, the circuit breaker with mechanical short-circuit short-delay function in this embodiment of the invention is achieved by adding a mechanical short-circuit short-delay trip unit 3 to a conventional circuit breaker, which satisfies the requirement that the DC circuit breaker can achieve short-circuit short-delay function without auxiliary power supply.

[0036] This invention may be implemented in other forms without departing from its spirit and essential characteristics. Therefore, the present embodiments are to be regarded as exemplary rather than limiting in all respects.

Claims

1. A circuit breaker with a mechanical short-circuit short-delay function, comprising a circuit breaker body (1), a transmission mechanism (2) disposed on the circuit breaker body (1), and an operating mechanism (5), characterized in that: The circuit breaker also includes a mechanical short-circuit short-delay trip unit (3), which is mounted on the circuit breaker body (1) and connected to the transmission mechanism (2). When the short-circuit current is greater than the set current value of the mechanical short-circuit short-delay trip unit (3), the mechanical short-circuit short-delay trip unit (3) will pull the transmission mechanism (2) for a delay. When the short-circuit current disappears, the transmission mechanism (2) will reset instantly. If the short-circuit current does not disappear within a certain time, the mechanical short-circuit short-delay trip unit (3) will trip the operating mechanism (5) through the transmission mechanism (2). The circuit breaker also includes a conductive busbar (4), and the mechanical short-circuit short-delay trip unit (3) is located between the circuit breaker body (1) and the conductive busbar (4). The mechanical short-circuit short-delay trip unit (3) includes a magnetic yoke (31), an armature (32), an energy storage spring (33a), an instantaneous spring (33b), a lever (34), an escapement (35), a ratchet (36a), a double-layer gear (36b), a pull rod (37), a rack (38), a single gear (36c), and a guide post (39). The magnetic yoke (31) is fixed on a magnetic yoke fixing plate (311), which is fixed on the circuit breaker body (1). An armature limiting baffle (312) is fixed on the upper part of the magnetic yoke (31) and at a position corresponding to the armature (32). The conductive bus (4) passes through the magnetic yoke (31). The instantaneous spring (33b) is sleeved on the guide post (39). The upper end of the moving spring (33b) is supported on the instantaneous spring force adjusting nut (391) screwed onto the guide post (39), while the lower end is supported on the instantaneous spring support seat (392) which is loosely fitted onto the guide post (39) and fixed to the front side of the magnetic yoke fixing plate (311). The armature (32) is threadedly fixed to the guide post (39). Under the action of the spring force of the instantaneous spring (33b), the armature (32) is displaced upward, and under the limitation of the armature limiting baffle (312), an air gap (321) is formed between the magnetic yoke (31) and the armature (32). The energy storage spring (33a) is fitted onto the guide post (39) at a position below the instantaneous spring support seat (392). The upper end of 33a) is supported on a guide post boss (393) formed on the guide post (39), and the lower end is supported on a pivot seat (341). The middle part of the pivot seat (341) is sleeved on the guide post (39) and corresponds to the left end of the lever cavity (342) of the lever (34). The front end and rear end of the pivot seat (341) are pivotally connected to the front and rear plates of the lever cavity (342) of the lever, which are the same shape and size, through a bearing (3411). The lower middle part of the lever (34) is hinged to the magnetic yoke fixing plate (311) through a lever pivot (343). A lever front and rear plate support shaft (344) is fixed between the upper central position of the front and rear plates of the lever cavity (342).A yoke fixing plate gear guard plate (3111) is fixed to the upper front part of the right end of the magnetic yoke fixing plate (3111). The space between the yoke fixing plate gear guard plate (3111) and the magnetic yoke fixing plate (3111) forms a lever movement space (3112). The escapement (35) is rotatably set in the lever movement space (3112) between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111) on opposite sides via the escapement pivot (351). The right end of the escapement (35) engages with the ratchet (36a), and when the ratchet (36a) rotates, the ratchet teeth (36d) of the ratchet (36a) engage with the ratchet (36a). The escapement fork (352) of the escapement (35) strikes, causing the escapement (35) to swing. Each swing of the escapement (35) disengages a ratchet tooth (36d). The ratchet (36a) is fixed to a pinion (36e) and rotatably mounted on a ratchet shaft (36f) along with the pinion (36e). The ratchet shaft (36f) is fixed between the magnetic yoke fixing plate (311) and the gear guard plate (3111) of the magnetic yoke fixing plate. The double-layer gear (36b) includes a double-layer gear large gear (36j) and a double-layer gear small gear (36k). The small gear (36e) and the double-layer gear large gear... (36j) meshes with the double-layer gear large gear (36j), the front side of which is fixed to the double-layer gear small gear (36k). The double-layer gear small gear (36k) is rotatably mounted between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111) via the double-layer gear shaft (36g). The double-layer gear small gear (36k) meshes with the single gear (36c), and the single gear (36c) is rotatably mounted on the single gear shaft (36i), which is fixed between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111) on opposite sides. A rack (38) is fixed to the middle of the pull rod (37) and meshes with the single gear (36c). The left end of the pull rod (37) extends into the lever cavity (342) and is connected to the lever front and rear plate support shaft (344) in a state corresponding to the middle of the lever front and rear plate support shaft (344). The middle of the pull rod (37) is movably positioned between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111), while the right end of the pull rod (37) extends to the right side between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111) and is connected to the transmission mechanism (2).

2. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: Between the magnetic yoke fixing plate (311) and the gear guard plate (3111) of the magnetic yoke fixing plate, and in the middle region corresponding to the length direction of the pull rod (37), there are a first guide roller pair (371) and a second guide roller pair (372) of the pull rod, which are vertically aligned with each other. The second guide roller pair (372) of the pull rod is located to the right of the first guide roller pair (371) of the pull rod and there are two sets of them. The middle part of the pull rod (37) is located between the first guide roller pair (371) and the second guide roller pair (372) of the pull rod and is simultaneously connected to the first guide roller pair (371) of the pull rod. The roller pair (371) and the second guide roller pair (372) in the middle of the pull rod form a sliding pair that slides left and right. The first guide roller pair (371) in the middle of the pull rod is rotatably disposed in the middle of the shaft (3711) of the first guide roller pair in the middle of the pull rod, and the second guide roller pair (372) in the middle of the pull rod is rotatably disposed on the shaft (3721) of the second guide roller pair in the middle of the pull rod. The shaft (3711) and the shaft (3721) of the first guide roller pair in the middle of the pull rod are fixed between the magnetic yoke fixing plate (311) and the gear guard plate (3111) of the magnetic yoke fixing plate.

3. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: The magnetic yoke fixing plate gear guard plate (3111) is fixed to the front side of the magnetic yoke fixing plate (311) by a set of spaced-apart suspended studs (31111), and the set of spaced-apart suspended studs (31111) forms the pull rod movement space (3112) between the magnetic yoke fixing plate (311) and the magnetic yoke fixing plate gear guard plate (3111).

4. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: A pull rod drive connection boss (373) is formed on the front side of the right end of the pull rod (37), which is connected to the transmission mechanism (2). The armature (32) is instantly attracted and drives the escapement (35) in sequence through the guide post (39), lever (34), pull rod (37), rack (38), single gear (36c), double-layer gear (36b) pinion (36k), double-layer gear (36b) large gear (36j), pinion (36e), and ratchet (36a). The escapement (35) slows down the action speed of the transmission mechanism (2) by the restraining effect of the escapement (35).

5. The circuit breaker with mechanical short-circuit short-delay function according to claim 4, characterized in that: The transmission mechanism (2) includes a transmission arm (21). At one end of the transmission arm (21) facing the pull rod (37), there is a transmission arm pull rod mating groove (211). The pull rod transmission connecting boss (373) on the front side of the right end of the pull rod (37) is connected to the transmission arm (21) at the position corresponding to the transmission arm pull rod mating groove (211). When the armature (32) is instantly attracted and pulls the escapement (35), the action speed of the transmission arm (21) is slowed down by the restraining effect of the escapement (35). When the short circuit current disappears, the transmission arm (21) is instantly reset under the action of the reaction spring.

6. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: The magnetic yoke (31) and armature (32) constitute an electromagnetic trip device. When a fault current occurs in the circuit, the current through the conductive bus (4) increases, and the electromagnetic force between the magnetic yoke (31) and armature (32) increases. Under the condition of forming an air gap (321) between the magnetic yoke (31) and armature (32), the armature (32) overcomes the reaction force of the instantaneous spring (33b) and moves downward and attracts the magnetic yoke (31).

7. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: A lever guard plate (313) is fixed to the front side of the magnetic yoke fixing plate (311) and at a position corresponding to the front of the lever (34) by a set of spaced-apart levitation bolts (3131). The lower center of the lever guard plate (313) extends toward the armature (32) to protect the armature (32). The space between the lever guard plate (313) and the magnetic yoke fixing plate (311) constitutes the lever movement space (3132). The magnetic yoke fixing plate (311) and the lever guard plate (313) are made of non-magnetic material to avoid short circuits in the magnetic circuit between the magnetic yoke (31) and the armature (32). The non-magnetic material is stainless steel or copper. The copper is brass.

8. The circuit breaker with mechanical short-circuit short-delay function according to claim 1, characterized in that: The yoke (31) is fixed to the front side of the yoke fixing plate (311) by means of the yoke limiting plate screw (3141), and the lower edge of the gear guard plate (3111) of the yoke fixing plate is supported on the upper surface of the right end of the yoke limiting plate (314). The short delay action time and return time can be changed by changing the ratio of the number of teeth of the rack (38) to the idle stroke, the ratio of the number of teeth between the double-layer gear (36b) and the single gear (36c) and the pinion (36e), and the mass of the escapement (35).

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