CN220172038U - Trip unit and circuit breaker - Google Patents

Abstract

The circuit breaker of release and applied release, including the coil skeleton, be provided with quiet iron core in the cavity of coil skeleton, move iron core subassembly and push rod, move the iron core subassembly and can slide and be close to or keep away from quiet iron core in order to drive the push rod of connecting in moving the iron core subassembly, move the iron core subassembly and move the iron core including first iron core and second, the first end of push rod slides and passes quiet iron core, the second end of push rod slides and passes first iron core and be connected with the second iron core that moves; the drive part of push rod is arranged in the moving track of the first movable iron core and is spaced from the first movable iron core, a first elastic piece is arranged between the first movable iron core and the static iron core, a limiting part is arranged in a cavity between the first movable iron core and the second movable iron core, a second elastic piece is arranged between the second movable iron core and the limiting part, and the elastic force of the second elastic piece is larger than that of the first elastic piece. The utility model can realize short-time delay protection and short-circuit instantaneous protection and has the advantages of simple structure, small occupied space and high reliability.

Description

Trip unit and circuit breaker

Technical Field

The utility model relates to the field of piezoelectric devices, in particular to a release and a circuit breaker.

Background

A circuit breaker is widely used in a low voltage distribution system as a device for protecting a power supply circuit. In general, a circuit breaker is composed of a contact system, an arc extinguishing system, an operating mechanism and an overcurrent protection device, under normal working conditions, the operating mechanism keeps the contact system closed or opened through a connecting rod transmission mechanism to connect and disconnect a power line, when an overcurrent fault occurs, the overcurrent protection device acts to trip the operating mechanism to rapidly cut off the overcurrent, wherein the most common structures for overcurrent protection are a magnetic trip device and a thermal trip device.

In a terminal power distribution system, a user generally sets a multi-stage breaker for protection, when fault current occurs at a load side, and the fault short-circuit current exceeds a short-circuit instantaneous action value of a lower-stage breaker, and simultaneously exceeds a short-circuit instantaneous action value of an upper-stage breaker, the condition that the upper-stage breaker and the lower-stage breaker trip simultaneously (namely, override trip) occurs can be caused, and in order to solve the override trip phenomenon of the upper-stage breaker and the lower-stage breaker, a short-circuit delay tripping device is generally arranged on the protection breaker, however, the short-circuit delay tripping device with a selective protection breaker is divided into an electronic type and a mechanical type at present, and the electronic type tripping device has the defects of higher cost, larger volume and the like, and the mechanical type has the defects of complex structure, poor stability and the like.

Disclosure of Invention

The utility model aims to overcome at least one defect of the prior art and provides a release and a circuit breaker which are simple in structure and high in reliability.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the release comprises a coil framework, a coil is wound on the outer side of the coil framework, a static iron core, a movable iron core component and a push rod are arranged in a cavity of the coil framework, the movable iron core component can slide to be close to or far from the static iron core to drive the push rod connected with the movable iron core component,

the movable iron core assembly comprises a first movable iron core and a second movable iron core, the first end of the push rod penetrates through the static iron core in a sliding mode, and the second end of the push rod penetrates through the first movable iron core in a sliding mode and is connected with the second movable iron core; the push rod is provided with a driving part which is positioned in the moving track of the first movable iron core and is spaced from the first movable iron core, a first elastic piece is arranged between the first movable iron core and the static iron core,

a limiting part is arranged in a cavity between the first movable iron core and the second movable iron core, a second elastic piece is arranged between the second movable iron core and the limiting part, and the elastic force of the second elastic piece is larger than that of the first elastic piece.

Preferably, the diameter of the first end of the push rod is larger than that of the second end of the push rod, so that a step part is formed in the middle of the push rod, and the step part faces the step surface of the first movable iron core to serve as a driving part.

Preferably, the limiting part divides the cavity into two chambers, a through hole for the push rod to pass is formed in the middle of the limiting part, the two chambers are axially communicated by the through hole, the first movable iron core and the second movable iron core are respectively arranged in the two chambers in a sliding manner, and the static iron core and the first movable iron core are positioned in the same chamber.

Preferably, the limiting part is a baffle structure, and a through hole is formed in the middle of the baffle structure.

Preferably, the limiting part is a boss which is arranged along the circumferential direction of the inner side wall of the cavity, and the height of the boss protruding out of the inner side wall of the cavity is smaller than the distance from the inner side wall of the cavity to the axis, so that the boss surrounds the cavity to form a through hole.

Preferably, the driving part is located between the first movable iron core and the static iron core, and the gap length between the first movable iron core and the driving part is smaller than or equal to the maximum compression amount of the first elastic piece, so that the first movable iron core and the driving part can be abutted.

Preferably, the first elastic piece and the second elastic piece are springs sleeved on the outer side of the push rod, two ends of the first elastic piece are respectively abutted with the first movable iron core and the static iron core, and two ends of the second elastic piece are respectively abutted with the second movable iron core and the limiting part.

Preferably, the static iron core and the first movable iron core are respectively provided with a first annular groove and a second annular groove, and the first annular groove and the second annular groove are opposite to each other at intervals and are used for limiting two ends of the first elastic piece.

Preferably, the second end of the push rod is inserted into the second movable iron core.

Preferably, the first end part of the push rod protrudes to form a first blocking part, the second end surface of the push rod is provided with a slot, and the slot is spliced with the splicing part arranged on the second movable iron core.

Preferably, the push rod is made of a non-metallic material.

The utility model also provides a circuit breaker comprising at least one circuit breaker pole equipped with a release as described above.

According to the release and the circuit breaker, when short-circuit short-time delay protection is realized, the limiting part enables the first movable iron core to only overcome the elasticity of the first elastic piece to conduct accelerated sliding before being matched with the driving part, when the first movable iron core is matched with the driving part, the first movable iron core simultaneously overcomes the elasticity of the first elastic piece and the elasticity of the second elastic piece to conduct deceleration movement, so that the push rod is extended in a delayed mode, when short-circuit instantaneous protection is realized, the second movable iron core overcomes the elasticity of the second elastic piece to drive the push rod, and when the release and the circuit breaker are applied to the circuit breaker, short-time delay protection and short-circuit instantaneous protection can be realized, and the release and the circuit breaker have the advantages of being simple in structure, small in occupied space and high in reliability.

In addition, the spacing portion separates the cavity into two cavities of axial intercommunication, and especially spacing portion can be baffle structure, or along the boss that the hoop set up, possesses simple structure, cost of manufacture low and convenient assembling's advantage.

In addition, the driving part is positioned between the static iron core and the movable iron core, and particularly, the driving part is formed by the step surface of the push rod, so that the device has the advantages of simple processing and small occupied space.

In addition, push rod and second move the iron core grafting cooperation, possess convenient assembling, connect stable advantage.

Drawings

FIG. 1 is a schematic diagram of the structure of a trip unit of the present utility model;

fig. 2 is a schematic diagram of a specific structure of the release according to the present utility model (the second movable iron core is provided with a plug-in portion);

FIG. 3 is a schematic diagram of a specific structure of the trip unit of the present utility model (the push rod is provided with a second blocking portion);

FIG. 4 is a schematic view showing the internal structure of the coil bobbin of the present utility model;

FIG. 5 is a schematic view of the structure of the push rod of the present utility model;

reference numerals:

the magnetic yoke comprises a 1-magnetic yoke body, a 2-coil framework, a 21-limiting part, a 22-through hole, a 23-positioning part, a 2 a-first cavity, a 2 b-second cavity, a 3-coil, a 41-first movable iron core, a 411-second annular groove, a 42-second movable iron core, a 421-plug-in part, a 5-static iron core, a 51-first annular groove, a 6-push rod, a 61-driving part, a 62-slot, a 63-first blocking part, a 64-second blocking part, a 7-first elastic piece and an 8-second elastic piece.

Detailed Description

Specific embodiments of the trip unit and circuit breaker of the present utility model are further described below with reference to the examples shown in the drawings. The trip unit and the circuit breaker of the present utility model are not limited to the descriptions of the following embodiments.

The circuit breaker of the embodiment comprises at least one circuit breaker pole, each circuit breaker pole comprises a pair of wiring terminals, a handle mechanism, an operating mechanism and a contact mechanism are arranged between the pair of wiring terminals, the contact mechanism comprises a moving contact and a fixed contact which are matched with each other, the moving contact and the fixed contact are respectively and electrically connected with the pair of wiring terminals, the handle mechanism, the operating mechanism and the moving contact are sequentially connected in a linkage way, and the operating handle mechanism can drive the moving contact to contact with or separate from the fixed contact, so that the switching-on and switching-off of the circuit breaker pole can be realized; the adjacent two circuit breaker poles are connected in a linkage way, namely the handle mechanisms and/or the operating mechanisms and/or the moving contacts of the adjacent two circuit breakers are respectively connected in a linkage way.

Furthermore, each breaker pole is also provided with a protection mechanism matched with the operating mechanism, the protection mechanism comprises a short-circuit protection mechanism and/or an overload protection mechanism, and when short-circuit or overload faults occur, the short-circuit protection mechanism or the overload protection mechanism triggers the operating mechanism to trip, so that the breaking of the breaker is interrupted.

The improvement point of the utility model is that the short-circuit protection mechanism adopts a release, the release comprises a coil framework 2, a coil 3 is wound on the outer side of the coil framework 2, a static iron core 5, a movable iron core component and a push rod 6 are arranged in a cavity of the coil framework 2, the movable iron core component can slide close to or far away from the static iron core 5 to drive the push rod 6 connected with the movable iron core component, the movable iron core component comprises a first movable iron core 41 and a second movable iron core 42, a first end of the push rod 6 slides through the static iron core 5, a second end of the push rod 6 slides through the first movable iron core 41 to be connected with the second movable iron core 42, a driving part 61 of the push rod 6 is positioned in a moving track of the first movable iron core 41 and is spaced from the first movable iron core 41, a first elastic piece 7 is arranged between the first movable iron core 41 and the static iron core 5, a limiting part 21 is arranged in the cavity between the first movable iron core 41 and the second movable iron core 42, a second elastic piece 8 is arranged between the second movable iron core 42 and the limiting part 21, and the elastic force of the second elastic piece 8 is larger than the elastic force of the first elastic piece 7.

When the current flowing through the coil 3 is smaller than the short-circuit short-time delay/instantaneous action setting value, the movable iron core component does not act; when the current flowing through the coil 3 is larger than a short-circuit short-time delay action setting value and smaller than a short-circuit instant action setting value, the first movable iron core 41 is driven by electromagnetic driving force to move towards the direction close to the static iron core 5, before the first movable iron core 41 is matched with the driving part 61, the limiting part 21 separates the first movable iron core 41 from the second elastic part 8, so that the first movable iron core 41 only overcomes the elastic force of the first elastic part 7 to accelerate movement, when the first movable iron core 41 moves to be matched with the driving part 61, the first movable iron core 41 pushes the driving part 61 and drives the push rod 6 to move, the second movable iron core 42 is driven in the process of moving the push rod 6, at the moment, the movable iron core assembly simultaneously overcomes the elastic force of the first elastic part 7 and the second elastic part 8, and the first movable iron core 41 moves towards the direction close to the static iron core 5 in a decelerating way under the resistance of the electromagnetic driving force, the first elastic part 7 and the second elastic part 8, and therefore the first end of the push rod 6 is delayed to extend out of the static iron core 5 for triggering an operating mechanism to trip, and short-circuit short-time delay protection is realized; when the current flowing through the coil 3 is larger than the setting value of the short-circuit instantaneous action, the first movable iron core 41 and the second movable iron core 42 are driven simultaneously, and the second movable iron core 42 drives the first end of the push rod 6 to extend out of the static iron core 5 for triggering the operating mechanism to trip, so that the short-circuit instantaneous protection is realized.

So, when realizing short-circuit short-time delay protection, spacing portion 21 makes first movable iron core 41 just overcome the elastic force of first elastic component 7 and accelerate the slip before cooperating with drive portion 61, when first movable iron core 41 cooperates with drive portion 61, first movable iron core 41 overcomes the elastic force deceleration motion of first elastic component 7 and second elastic component 8 simultaneously, thereby make push rod 6 time delay stretch out, when realizing short-circuit instantaneous protection, second movable iron core 42 overcomes the elastic force drive push rod 6 of second elastic component 8, in being applied to the circuit breaker, can realize short-time delay action, possess simple structure, occupation space is little and the advantage that the reliability is high.

Preferably, the spacing portion 21 separates the cavity of the coil bobbin 2 into two cavities, and a through hole 22 for axially communicating the two cavities is arranged in the middle of the spacing portion 21, so that the push rod 6 can pass through the through hole 22, the first movable iron core 41 and the second movable iron core 42 are respectively arranged in the two cavities in a sliding manner, the static iron core 5 and the first movable iron core 41 are positioned in the same cavity, and the first movable iron core 41 and the second movable iron core 42 are respectively positioned in the two cavities, so that the assembly is convenient.

Specifically, the limiting part 21 can be a baffle structure arranged in the cavity, the middle part of the baffle structure is provided with the through hole 22, the structure is simple, the processing is convenient, or the limiting part 21 is at least two bosses which are arranged around the protrusion of the inner side wall of the cavity, a gap is reserved between every two adjacent bosses, the height of each boss protruding out of the inner side wall of the cavity is smaller than the distance from the inner side wall of the cavity to the axle center, and at least the bosses are surrounded to form the through hole 22, so that the material can be saved, and the cost is reduced.

Further, the second movable iron core 42 is inserted into the second end of the push rod 6, and the movable iron core and the push rod 6 can be inserted into each other through the end portion, so that the length of the push rod 6 can be shortened, and of course, the movable iron core can be penetrated through the push rod 6 in a limited manner, so that the connection stability of the movable iron core and the push rod 6 can be improved.

Embodiments of trip units are provided in connection with fig. 1-5.

As shown in fig. 1, the release includes a yoke 1 and a coil bobbin 2 assembled on the yoke 1, the coil bobbin 2 is hollow and cylindrical as a whole, a coil 3 is wound on the outer side of the coil bobbin 2, and a hollow portion of the coil bobbin 2 is used as a cavity of the coil bobbin 2 for assembling a stationary core 5, a movable core assembly and a push rod 6.

As shown in fig. 1-4, the movable iron core assembly and the static iron core 5 are respectively disposed at two ends of the cavity of the coil skeleton 2, the push rod 6 is connected with the movable iron core assembly and is driven by the movable iron core assembly to move along the axis of the cavity, wherein the static iron core 5 is fixedly assembled in the cavity, preferably, a positioning part 23 is disposed in the cavity, the positioning part 23 is a bar-shaped boss structure in fig. 4, so as to strengthen the matching degree between the static iron core 5 and the inner side wall of the cavity, prevent the static iron core 5 from falling off, a through hole is disposed in the middle of the static iron core 5, the movable iron core assembly comprises a first movable iron core 41 and a second movable iron core 42, the first movable iron core 41 is disposed between the second movable iron core 42 and the static iron core 5, the first end of the push rod 6 slides through the through hole of the static iron core 5, and the second end of the push rod 6 slides through the first movable iron core 41 and is connected with the second movable iron core 42.

The limiting part 21 is arranged on the inner side wall of the cavity between the first movable iron core 41 and the second movable iron core 42, the limiting part 21 divides the cavity into two cavities, in the embodiment, the two cavities are a first cavity 2a and a second cavity 2b respectively, the first movable iron core 41 and the static iron core 5 are arranged in the first cavity 2a, the static iron core 5 is fixedly arranged at one end far away from the limiting part 21, the first movable iron core 41 can slide along the push rod 6 between the static iron core 5 and the limiting part 21, the second movable iron core 42 is slidably arranged in the second cavity 2b, the limiting part 21 of the preferred embodiment is a baffle structure, a through hole 22 is arranged in the middle of the baffle structure, the inner diameter of the through hole 22 is equal to the outer diameter of the push rod 6, or the inner diameter of the through hole 22 is slightly larger than the outer diameter of the push rod 6, and redundant shaking of the push rod 6 can be avoided in the moving process to a certain extent.

The first elastic piece 7 is arranged between the first movable iron core 41 and the static iron core 5, the second elastic piece 8 is arranged between the second movable iron core 42 and the limiting part 21, namely, the first elastic piece 7 and the second elastic piece 8 are respectively arranged in the first cavity 2a and the second cavity 2b, and the elastic force of the first elastic piece 7 is smaller than that of the second elastic piece 8, so when the current flowing through the coil 3 is larger than the short-circuit short-time delay action setting value and smaller than the short-circuit instantaneous action setting value, after the movable iron core assembly receives electromagnetic driving force, the first movable iron core 41 can overcome the elastic force of the first elastic piece 7 to move along the push rod 6 towards the direction close to the static iron core 5, and the second movable iron core 42 cannot overcome the elastic force of the second elastic piece 8.

In this embodiment, the first elastic member 7 and the second elastic member 8 are springs that can be sleeved outside the push rod 6, and in fig. 1-3, the outer diameter of each spring is approximately equal to the inner diameter of the cavity, two ends of the first elastic member 7 are respectively abutted against the stationary iron core 5 and the first movable iron core 41, and two ends of the second elastic member 8 are respectively abutted against the limiting portion 21 and the second movable iron core 42; further, as shown in fig. 2 and 3, the stationary core 5 and the first movable core 41 are respectively provided with a first annular groove 51 and a second annular groove 411, and the first annular groove 51 and the second annular groove 411 are spaced at opposite ends for limiting the first elastic member 7, so that the degree of fit between the first elastic member 7 and the stationary core 5 and the first movable core 41 is improved.

The push rod 6 is provided with a driving part 61 for being matched with the first movable iron core 41, the driving part 61 is located in the moving track of the first movable iron core 41, and a certain interval is reserved between the driving part 61 and the first movable iron core 41 in the initial position, in the embodiment, the driving part 61 is located in the middle of the push rod 6 between the first movable iron core 41 and the static iron core 5, preferably, the driving part 61 is of a boss structure capable of being abutted with the movable first iron core 41, and the interval length between the driving part 61 and the first movable iron core 41 is smaller than or equal to the maximum compression amount of the first elastic piece 7, so that the first movable iron core 41 can be abutted with the driving part 61 under the driving of electromagnetic driving force to drive the push rod 6 to move.

A specific construction of the push rod 6 is provided in connection with fig. 1-3 and 5.

The push rod 6 is made of a nonmetallic material and is in a rod body structure, the diameter of the first end of the push rod 6 is larger than that of the second end of the push rod 6, so that a step part is formed in the middle of the push rod 6, the outer diameter of the step part is smaller than or equal to the inner diameter of a through hole of the fixed iron core 5, the step surface of the step part, which faces the first movable iron core 41, is used as a driving part 61, a first blocking part 63 is formed at the end part of the first end of the push rod 6 in a protruding mode, the outer diameter of the first blocking part 63 is larger than the inner diameter of the through hole of the fixed iron core 5, the first blocking part 63 is positioned on the side, away from the first movable iron core 41, of the fixed iron core 5, the second end of the push rod 6 is inserted into the second movable iron core 42, in fig. 5, a slot 62 is formed at the end face of the second movable iron core 42, which faces the push rod 6, a plug part 421 is arranged in a protruding mode, and the plug part 421 is inserted into the slot 62; alternatively, as shown in fig. 3, a communication hole 22 is penetrating through the middle part of the second movable iron core 42, and the second end of the push rod 6 is inserted into the communication hole 22, preferably, a second blocking part 64 is arranged at the second end of the push rod 6, and the second blocking part 64 is located at one side of the second movable iron core 42 away from the first movable iron core 41 to realize limit insertion.

The working principle of the release is as follows:

when the release is at the initial position, the current flowing through the coil 3 does not reach the setting value of short-circuit short-time delay action, the electromagnetic driving force of the coil 3 borne by the movable iron core assembly is smaller than the initial pressure of the first elastic piece 7, and the movable iron core assembly does not move, namely the first movable iron core 41 and the second movable iron core 42 do not act; when the current flowing through the coil 3 reaches the short-circuit short-time delay action setting value and is smaller than the short-circuit instantaneous setting value, the electromagnetic driving force borne by the first movable iron core 41 is larger than the initial pressure of the first elastic piece 7, the first movable iron core 41 starts to accelerate until the first movable iron core 41 is abutted against the driving part 61, the first movable iron core 41 is displaced by the distance between the first movable iron core 41 and the driving part 61, in the process, the second movable iron core 42 is also subjected to electromagnetic driving force, but due to the fact that the electromagnetic driving force is smaller than the initial pressure of the second elastic piece 8, the second movable iron core 42 does not act, when the first movable iron core 41 is matched with the driving part 61 to drive the push rod 6 to move, the first movable iron core 41 is decelerated under the combined action of the electromagnetic driving force and the elastic force of the first elastic piece 7 and the second elastic piece 8, the second movable iron core 42 is jointly driven by the electromagnetic driving force and the push rod 6 to overcome the elastic force of the second elastic piece 8 until the first end of the push rod 6 can trigger the operating mechanism to release, the breaker is switched off, no breaking current is generated in a circuit, and the movable assembly is not subjected to the electromagnetic driving force and returns to the initial reaction force under the action of the first elastic piece 7 and the second elastic piece 8.

When the current flowing through the coil 3 reaches the setting value of the short-circuit instantaneous action, the movement path of the first movable iron core 41 is consistent with the short-circuit short delay, and the difference is that the electromagnetic driving force born by the second movable iron core 42 is larger than the counter force of the second elastic piece 8 to accelerate movement due to the larger current flowing through the coil 3 until the breaker is opened, when the short-circuit current is not broken in the circuit, the movable iron core assembly is not driven by the electromagnetic driving force any more, and all parts return to the initial positions.

The circuit breaker comprises at least one circuit breaker pole, wherein the tripper in the embodiment is assembled in one circuit breaker pole, the magnetic yoke 1 of the tripper and the fixed contact of the circuit breaker pole are connected to the same wiring terminal, and the tripper can realize short-circuit short-time delay protection and short-circuit instantaneous protection in the circuit breaker pole; a thermal overload release can be further assembled in each circuit breaker pole, so that overload long-time delay protection is realized.

It should be noted that, in the description of the present utility model, the terms "upper", "lower", "left", "right", "inner", "outer", and the like indicate an orientation or a positional relationship based on that shown in the drawings or an orientation or a positional relationship conventionally put in use, and are merely for convenience of description, and do not indicate that the apparatus or element to be referred to must have a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating relative importance.

The foregoing is a further detailed description of the utility model in connection with the preferred embodiments, and it is not intended that the utility model be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the utility model, and these should be considered to be within the scope of the utility model.

Claims (12)

1. The release comprises a coil framework (2), a coil (3) is wound on the outer side of the coil framework (2), a static iron core (5), a movable iron core assembly and a push rod (6) are arranged in a cavity of the coil framework (2), and the movable iron core assembly can slide to be close to or far away from the static iron core (5) to drive the push rod (6) connected with the movable iron core assembly, and is characterized in that:

the movable iron core assembly comprises a first movable iron core (41) and a second movable iron core (42), a first end of the push rod (6) slides through the static iron core (5), and a second end of the push rod (6) slides through the first movable iron core (41) and is connected with the second movable iron core (42); the push rod (6) is provided with a driving part (61), the driving part (61) is positioned in the moving track of the first movable iron core (41) and is spaced from the first movable iron core (41), a first elastic piece (7) is arranged between the first movable iron core (41) and the static iron core (5),

a limiting part (21) is arranged in a cavity between the first movable iron core (41) and the second movable iron core (42), a second elastic piece (8) is arranged between the second movable iron core (42) and the limiting part (21), and the elastic force of the second elastic piece (8) is larger than that of the first elastic piece (7).

2. The release of claim 1, wherein: the diameter of the first end of the push rod (6) is larger than that of the second end of the push rod (6), so that a step part is formed in the middle of the push rod (6), and the step part faces the step surface of the first movable iron core (41) to serve as a driving part (61).

3. The release of claim 1, wherein: the limiting part (21) divides the cavity into two chambers, a through hole (22) for the push rod (6) to pass is formed in the middle of the limiting part (21), the two chambers are axially communicated by the through hole (22), the first movable iron core (41) and the second movable iron core (42) are respectively arranged in the two chambers in a sliding mode, and the static iron core (5) and the first movable iron core (41) are located in the same chamber.

4. The release of claim 3, wherein: the limiting part (21) is of a baffle structure, and a through hole (22) is formed in the middle of the baffle structure.

5. The release of claim 3, wherein: the limiting part (21) is a boss which is arranged along the circumferential direction of the inner side wall of the cavity, and the height of the boss protruding out of the inner side wall of the cavity is smaller than the distance from the inner side wall of the cavity to the axis, so that the boss surrounds the cavity to form a through hole (22).

6. The release of claim 1, wherein: the driving part (61) is positioned between the first movable iron core (41) and the static iron core (5), and the gap length between the first movable iron core (41) and the driving part (61) is smaller than or equal to the maximum compression amount of the first elastic piece (7), so that the first movable iron core (41) can be abutted with the driving part (61).

7. The release of claim 1, 2 or 6, wherein: the first elastic piece (7) and the second elastic piece (8) are springs sleeved on the outer side of the push rod (6), two ends of the first elastic piece (7) are respectively abutted with the first movable iron core (41) and the static iron core (5), and two ends of the second elastic piece (8) are respectively abutted with the second movable iron core (42) and the limiting part (21).

8. The release of claim 7, wherein: the static iron core (5) and the first movable iron core (41) are respectively provided with a first annular groove (51) and a second annular groove (411), and the first annular groove (51) and the second annular groove (411) are opposite in interval and used for limiting two ends of the first elastic piece (7).

9. The release of claim 1, wherein: the second end of the push rod (6) is inserted into the second movable iron core (42).

10. The release of claim 1, 2, 6 or 9, wherein: the first end part of the push rod (6) protrudes to form a first blocking part (63), the second end surface of the push rod (6) is provided with a slot (62), and the slot (62) is spliced with a splicing part (421) arranged on the second movable iron core (42).

11. The release of claim 1, wherein: the push rod (6) is made of a nonmetallic material.

12. Circuit breaker, including at least one circuit breaker pole, its characterized in that: the circuit breaker pole is equipped with a release according to any one of claims 1-11.