Contact device and switchgear

Abstract

The application belongs to the technical field of low-voltage electrical apparatus, and discloses a contact device and a switching electrical apparatus. The contact device comprises a static contact assembly and a dynamic contact assembly. The static contact assembly comprises a static contact plate and a static contact, and the static contact is arranged on the static contact plate. The dynamic contact assembly comprises a dynamic contact bridge, a dynamic contact, a magnetic yoke and an armature. The end of the dynamic contact bridge is provided with the dynamic contact, the dynamic contact can be in contact with the static contact, the armature is sleeved on the dynamic contact bridge and extends to the direction of the magnetic yoke, and when the dynamic contact is repelled from the static contact, the armature abuts against the magnetic yoke, so that the armature and the magnetic yoke form a magnetic flux loop. The contact device can effectively prolong the return time of the dynamic contact, prevent the contact from reigniting and breaking down, and improve the safety of the contact device and the switching electrical apparatus.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage electrical apparatus, in particular to a contact device and a switching electrical apparatus. BACKGROUND

[0002] The contact device is a necessary component of the switching electrical apparatus, which is used to connect, carry and break the current flowing through the main circuit of the switching electrical apparatus during operation. The switching electrical apparatus containing the contact device includes circuit breakers, contactors, intermediate relays, motor starters and other products. Generally, the above-mentioned switching electrical apparatus includes one or more moving contacts and one or more associated stationary contacts. The moving contact and the stationary contact are engaged during normal operation to complete the current carrying path through the switching electrical apparatus. The moving contact and the stationary contact are separated in the event of current overload, thermal protection or other unexpected events, and the coil voltage of the switching electrical apparatus is powered off in the desired event of turning off the circuit breaker, the intermediate relay or the contactor.

[0003] When the contacts are separated, an arc is generated. If the arc cannot be quickly dissipated, extinguished or quenched, it will cause damage to the contacts, the device itself or the load being protected. In the prior art, the contact device, after the contacts repel, the moving contact returns to the position too quickly, the moving contact contacts the stationary contact or reaches a distance that can be broken down, which easily causes a reignition phenomenon, resulting in ineffective arc extinguishing, and the reignition burns seriously or even explodes, which seriously threatens the safety of the switching electrical apparatus.

[0004] Therefore, it is urgent to improve the contact device and the switching electrical apparatus to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a contact device and a switching electrical apparatus, which can effectively prolong the return time of the moving contact, prevent the reignition of the contact, and improve the safety of the contact device and the switching electrical apparatus.

[0006] To achieve this purpose, the present application adopts the following technical solutions:

[0007] The contact device comprises:

[0008] The stationary contact assembly comprises a stationary contact plate and a stationary contact, and the stationary contact is arranged on the stationary contact plate.

[0009] The moving contact assembly comprises a moving contact bridge, a moving contact, a magnetic yoke and an armature. The end of the moving contact bridge is provided with the moving contact, the moving contact can be in contact with the stationary contact, the armature is sleeved on the moving contact bridge and extends to the direction of the magnetic yoke, and when the moving contact and the stationary contact repel, the armature abuts against the magnetic yoke, so that the armature and the magnetic yoke form a magnetic flux loop.

[0010] As an option, the armature comprises an abutting portion and two extension portions, the abutting portion is attached to the side of the movable contact bridge away from the magnetic yoke, and the two extension portions are respectively connected to the two sides of the abutting portion and extend towards the magnetic yoke along the side of the movable contact bridge.

[0011] As an option, the extension portion comprises two extension plates arranged at intervals, and the two extension plates are respectively connected to the two ends of the abutting portion.

[0012] As an option, the movable contact assembly further comprises a resilient member arranged between the magnetic yoke and the movable contact bridge, and the resilient member can apply an elastic force to the movable contact bridge to move the movable contact bridge towards the stationary contact to make the movable contact and the stationary contact contact and conduct.

[0013] As an option, the side of the movable contact bridge facing the magnetic yoke is provided with a limiting protrusion, and the resilient member is sleeved on the limiting protrusion, and the limiting protrusion is used to limit the swing of the resilient member.

[0014] As an option, the stationary contact plate is provided with a U-shaped hole, at least part of the current flow around the U-shaped hole is opposite to the current flow in the movable contact bridge, and the stationary contact is connected to the stationary contact plate surrounded by the U-shaped hole.

[0015] As an option, the stationary contact plate comprises a first contact plate, two second contact plates and a third contact plate, the first contact plate, the two second contact plates and the third contact plate are arranged around the U-shaped hole, one end of the first contact plate is a wiring end, the other end of the first contact plate extends to the bottom side of the U-shaped hole, the second contact plate is connected to the first contact plate, the second contact plate connects the third contact plate and the first contact plate, the current flows into the stationary contact in sequence through the first contact plate, the two second contact plates and the third contact plate, the current in the movable contact assembly flows to the center of the movable contact bridge through the movable contact and the movable contact bridge, and the current flow direction in the second contact plate is opposite to the current flow direction in the movable contact bridge.

[0016] As an option, the distance between the movable contact bridge and the stationary contact plate gradually increases outward from the contact position of the movable contact and the stationary contact.

[0017] A switch electric appliance comprising the contact device as described above, the switch electric appliance further comprises an arc extinguishing chamber, and each end of the movable contact bridge is provided with one arc extinguishing chamber, and the arc generated by the separation of the movable contact and the stationary contact is introduced into the arc extinguishing chamber.

[0018] As an option, the switch electric appliance further comprises an arc guide plate, the arc guide plate connects the two arc extinguishing chambers, and the magnetic yoke is arranged on the arc guide plate.

[0019] Advantages:

[0020] The contact device provided by the application sets the armature to be sleeved on the movable contact bridge and extends to the direction of the magnetic yoke, the armature and the magnetic yoke form an electromagnetic loop, the electromagnetic loop encloses the movable contact bridge, and the short-circuit current in the movable contact bridge can be sensed in time, when the magnetic field generated by the short-circuit current in the movable contact bridge exceeds a certain value, the force generated by the magnetic field tends to drive the movable contact bridge to move to the direction close to the magnetic yoke. At the same time, due to the action of the electric repulsive force, the movable contact bridge moves to form a magnetic flux path closed loop with the armature and the magnetic yoke, and a closed magnetic loop is generated, at this time, the magnetic force generated by the magnetic field can offset part of the rebound reset force of the movable contact to the static contact, the reset time of the movable contact bridge is prolonged, the time of the large opening distance between the movable contact and the static contact is increased, the breakdown and reignition between the contacts are avoided, and the arc extinguishing capacity is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a cross-sectional structure schematic diagram of a switch device provided by the embodiment of the application;

[0022] Figure 2 is a cross-sectional structure schematic diagram of a movable contact assembly provided by the embodiment of the application;

[0023] Figure 3 is a three-dimensional structure schematic diagram of the movable contact assembly provided by the embodiment of the application;

[0024] Figure 4 is a three-dimensional structure schematic diagram of a static contact assembly provided by the embodiment of the application;

[0025] Figure 5 is a schematic diagram of the current flow direction in the static contact plate and the movable contact bridge provided by the embodiment of the application.

[0026] In the drawings:

[0027] 1, static contact assembly; 11, static contact plate; 110, U-shaped hole; 111, first contact plate; 112, second contact plate; 113, third contact plate; 12, static contact;

[0028] 2, movable contact assembly; 21, movable contact bridge; 211, limiting protrusion; 22, movable contact; 23, magnetic yoke; 24, armature; 241, abutting portion; 242, extension portion; 2421, extension plate; 25, elastic member;

[0029] 3, arc extinguishing chamber;

[0030] 4, arc plate;

[0031] 5, base;

[0032] 6, contact support. DETAILED DESCRIPTION

[0033] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are intended to be merely illustrative of the application and not in limitation thereof. It should also be noted that, for the purpose of clarity, only those structures of the application that are relevant to the present application have been shown in the drawings.

[0034] In the description of the present application, unless specifically defined and limited otherwise, the terms "connected", "connected to", "fixed", "fixed to" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the present application, unless specifically defined and limited otherwise, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0036] In the description of the present embodiment, the terms "up", "down", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, which is only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used to distinguish in description and have no special meaning.

[0037] As Figure 1 As shown in the drawings, the present embodiment provides a switching electrical appliance, which can be a circuit breaker, a contactor, an intermediate relay, a motor starter and the like. The switching electrical appliance includes a housing, two arc extinguishing chambers 3 and a contact device, the arc extinguishing chambers 3 and the contact device are arranged in the housing, the arc extinguishing chambers 3 are provided with two arc extinguishing chambers 3, the two arc extinguishing chambers 3 are respectively located on both sides of the contact device, and the arc generated by the contact device is introduced into the arc extinguishing chambers 3 for arc extinguishing.

[0038] The switching device also includes an arc-starting plate 4, which is mounted on the base 5 of the housing. The arc-starting plate 4 connects two arc-extinguishing chambers 3, and the contact device is mounted on the arc-starting plate 4. By using the arc-starting plate 4 to connect the two arc-extinguishing chambers 3 in series, it is beneficial to increase the arc voltage.

[0039] The contact assembly includes a moving contact 22 and a stationary contact 12, which engage during normal operation to complete the current carrying path through the switching device. In the event of current overload, thermal protection or other undesirable events, and in the event of desired events such as the de-energization of the switching device's coil voltage, the moving contact 22 and the stationary contact 12 are separated.

[0040] When the contacts separate, an electric arc is generated. If the arc cannot be quickly dissipated, extinguished, or quenched, it will damage the contacts, the equipment itself, or the load being protected. In existing contact devices, after the contacts are repelled, the moving contact 22 returns to its original position in too short a time. If the moving contact 22 comes into contact with the stationary contact 12 or reaches a breakdown distance, reignition is likely to occur, resulting in ineffective arc extinguishing. In severe cases, reignition can even lead to explosion, seriously threatening the safety of the switching equipment.

[0041] To address the above issues, this embodiment improves the contact device to extend the reset time after the contacts are pushed apart, thereby preventing breakdown and reignition between the contacts.

[0042] Specifically, such as Figures 1-3 As shown, the contact device includes a stationary contact assembly 1 and a moving contact assembly 2. The stationary contact assembly 1 includes a stationary contact plate 11 and a stationary contact 12, with the stationary contact 12 disposed on the stationary contact plate 11. The moving contact assembly 2 includes a moving contact bridge 21, a moving contact 22, a magnetic yoke 23, and an armature 24. The moving contact bridge 21 has a moving contact 22 at its end, which can make contact with the stationary contact 12 to conduct electricity. The armature 24 is sleeved on the moving contact bridge 21 and extends in the direction of the magnetic yoke 23. When the moving contact 22 and the stationary contact 12 are repelled, the armature 24 abuts against the magnetic yoke 23, so that the armature 24 and the magnetic yoke 23 form a closed magnetic path.

[0043] By setting the armature 24 to cover the movable contact bridge 21 and extend towards the magnetic yoke 23, the armature 24 and the magnetic yoke 23 form an electromagnetic loop, which encloses the movable contact bridge 21, and can instantly induce the short-circuit current in the movable contact bridge 21. When the magnetic field generated by the short-circuit current in the movable contact bridge 21 exceeds a certain value, the force generated by the magnetic field tends to drive the movable contact bridge 21 to move towards the magnetic yoke 23. At the same time, due to the action of the electro-repulsion force, the movable contact bridge 21 moves to form a magnetic flux path closed loop with the armature 24 and the magnetic yoke 23, generating a closed magnetic loop. At this time, the magnetic force generated by the magnetic field can offset part of the restoring force of the movable contact head 22 to the static contact 12, prolong the reset time of the movable contact bridge 21, increase the time of the large opening distance between the movable contact head 22 and the static contact 12, avoid the breakdown and reignition between the contacts, and improve the arc extinguishing capability.

[0044] Further, as shown in Figure 1 , the distance between the movable contact bridge 21 and the static contact plate 11 gradually increases outward from the contact position of the movable contact head 22 and the static contact 12. That is, the movable contact bridge 21 and the static contact plate 11 form a horn mouth shape towards the arc extinguishing chamber 3, thereby more facilitating the introduction of the arc between the contacts into the arc extinguishing chamber 3.

[0045] In this embodiment, the movable contact bridge 21 is provided with one movable contact head 22 at each end, and the two movable contact heads 22 correspond to the two arc extinguishing chambers 3 respectively. The arc generated by the separation of the movable contact head 22 and the static contact 12 is introduced into the arc extinguishing chamber 3.

[0046] Further, as shown in Figure 3 , the armature 24 includes an abutting portion 241 and two extension portions 242. The abutting portion 241 is attached to the side of the movable contact bridge 21 away from the magnetic yoke 23, and the two extension portions 242 are respectively connected to the two sides of the abutting portion 241 and extend towards the magnetic yoke 23 along the side surface of the movable contact bridge 21. The abutting portion 241 and the two extension portions 242 form a U-shaped structure, which covers three surfaces of the movable contact bridge 21, so that the armature 24 and the magnetic yoke 23 form a magnetic system loop.

[0047] Optionally, as shown in Figure 3 , the extension portion 242 includes two extension plates 2421 arranged at intervals, and the two extension plates 2421 are respectively connected to the two ends of the abutting portion 241. When the armature 24 moves towards the magnetic yoke 23, the four extension plates 2421 abut the four corners of the square magnetic yoke 23 respectively.

[0048] Further, as shown in Figure 3As shown, the moving contact assembly 2 further comprises a resilient member 25, which is arranged between the magnetic yoke 23 and the moving contact bridge 21, and is capable of exerting a resilient force on the moving contact bridge 21 to move the moving contact bridge 21 towards the stationary contact 12 to make the moving contact 22 contact and conduct with the stationary contact 12. The resilient member 25 is arranged at a middle position of the moving contact bridge 21, and the two moving contacts 22 are symmetrically distributed relative to the resilient member 25. The resilient member 25 can be a spring.

[0049] When the switch appliance is normally on, the moving contact bridge 21 is moved towards the stationary contact 12 under the resilient force of the resilient member 25, so that the moving contact 22 contacts the stationary contact 12 to realize conduction. When the switch appliance is normally broken, the operating mechanism (not shown in the figure) presses the contact support 6 to overcome the resilient force of the resilient member 25, and pushes the moving contact bridge 21 to move away from the stationary contact 12, so that the moving contact 22 is separated from the stationary contact 12. When the switch appliance is short-circuited, the moving contact 22 and the stationary contact 12 repel each other to overcome the resilient force of the resilient member 25. It should be noted that the operating mechanism and the contact support 6 are conventional structures in the switch appliance, and the specific structure, connection mode and working principle thereof will not be described in detail here.

[0050] Optionally, as shown in Figure 3 The moving contact bridge 21 is provided with a limiting protrusion 211 on the side facing the magnetic yoke 23, and the resilient member 25 is sleeved on the limiting protrusion 211. The limiting protrusion 211 is used to limit the swing of the resilient member 25, and is conducive to the stable installation of the resilient member 25.

[0051] In the prior art, when the switch appliance is short-circuited, the electric repulsion force that separates the moving contact 22 from the stationary contact 12 is insufficient, which results in a long repulsion stagnation time and a small repulsion distance of the moving contact 22 after short-circuiting, and there is a high risk of inter-contact breakdown and reignition.

[0052] To solve the above problems, the stationary contact assembly 1 is also improved in the embodiment to further improve the short-circuit breaking capacity of the contact device. Specifically, as shown in Figure 4 and Figure 5 The stationary contact plate 11 is provided with a U-shaped hole 110, and at least part of the current flow around the U-shaped hole 110 is opposite to the current flow in the moving contact bridge 21. The stationary contact 12 is connected to the stationary contact plate 11 surrounded by the U-shaped hole 110.

[0053] By setting the U-shaped hole 110 on the static contact plate 11, and connecting the static contact 12 to the static contact plate 11 surrounded by the U-shaped hole 110, the current in the static contact plate 11 is diverted by 90° when flowing to the static contact 12, the current in the static contact plate 11 is opposite to the current in the moving contact bridge 21, the increase of the Lorentz magnetic force generated by the interaction of the currents in the conductive loop is realized, that is, the increase of the electric repulsion, the repulsion stagnation time after the short circuit of the moving contact bridge 21 is reduced, the starting current of the breaking of the moving contact 22 is reduced, the current limiting capability is improved, at the same time, the electric repulsion between the contacts is increased, the repulsion distance of the moving contact bridge 21 is increased, which is beneficial to increase the arc voltage.

[0054] Specifically, as shown in Figure 3 and Figure 4 , the static contact plate 11 comprises a first contact plate 111, two second contact plates 112 and a third contact plate 113, the first contact plate 111, the two second contact plates 112 and the third contact plate 113 are arranged around the U-shaped hole 110, one end of the first contact plate 111 is a wiring end, the other end of the first contact plate 111 extends to the bottom side of the U-shaped hole 110, the second contact plate 112 connects the third contact plate 113 and the first contact plate 111, the third contact plate 113 is located between the two second contact plates 112, the current flows into the static contact 12 through the first contact plate 111, the two second contact plates 112 and the third contact plate 113 in turn, the current in the moving contact assembly 2 flows to the center of the moving contact bridge 21 through the moving contact 22 and the moving contact bridge 21, the current in the second contact plate 112 flows in the opposite direction to the current in the moving contact bridge 21. The current flow direction in the second contact plate 112 is shown by arrow a in Figure 5 , and the current flow in the moving contact bridge 21 is shown by arrow b in Figure 5 .

[0055] Obviously, the above embodiments of the present application are only examples for clarity, and are not intended to limit the embodiments of the present application. Those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. It is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. Contact device, characterized in that The application relates to a contactor, which comprises a static contact assembly (1) and a dynamic contact assembly (2). The dynamic contact assembly (2) comprises a dynamic contact bridge (21), a dynamic contact (22), a magnetic yoke (23) and an armature (24), the end of the dynamic contact bridge (21) is provided with the dynamic contact (22), the dynamic contact (22) can be in contact with the static contact (12) to realize conduction, the armature (24) is sleeved on the dynamic contact bridge (21) and extends towards the magnetic yoke (23), when the dynamic contact (22) is repelled from the static contact (12), the armature (24) abuts against the magnetic yoke (23), so that the armature (24) and the magnetic yoke (23) form a magnetic flux closed loop, and the magnetic force generated by a magnetic field can offset part of the reset force of the dynamic contact (22) towards the static contact (12). The armature (24) comprises an abutting portion (241) and two extension portions (242), the abutting portion (241) is attached to the side of the dynamic contact bridge (21) which is away from the magnetic yoke (23), and the two extension portions (242) are respectively connected to the two sides of the abutting portion (241) and extend towards the magnetic yoke (23) along the side of the dynamic contact bridge (21).

2. The contact device of claim 1, wherein The extension portion (242) comprises two extension plates (2421) which are arranged at intervals, and the two extension plates (2421) are respectively connected to the two ends of the abutting portion (241).

3. The contact device of claim 2, wherein, The dynamic contact assembly (2) further comprises an elastic member (25), the elastic member (25) is arranged between the magnetic yoke (23) and the dynamic contact bridge (21), and the elastic member (25) can exert an elastic force on the dynamic contact bridge (21) to make the dynamic contact bridge (21) move towards the static contact (12) and make the dynamic contact (22) contact and conduct with the static contact (12).

4. The contact device of claim 1, wherein, The side of the dynamic contact bridge (21) which faces the magnetic yoke (23) is provided with a limiting protrusion (211), and the elastic member (25) is sleeved on the limiting protrusion (211).

5. The contact device of claim 4, wherein, The static contact plate (11) is provided with a U-shaped hole (110), at least part of the current flow around the U-shaped hole (110) is opposite to the current flow in the dynamic contact bridge (21), and the static contact (12) is connected to the static contact plate (11) surrounded by the U-shaped hole (110).

6. The contact device of claim 1, wherein, ​ 7. The contact device of claim 6, wherein, The static contact plate (11) comprises a first contact plate (111), two second contact plates (112) and a third contact plate (113), the first contact plate (111), the two second contact plates (112) and the third contact plate (113) are arranged around the U-shaped hole (110), one end of the first contact plate (111) is a wiring end, the other end of the first contact plate (111) extends to the bottom side of the U-shaped hole (110), the second contact plate (112) is connected with the first contact plate (111), the second contact plate (112) connects the third contact plate (113) and the first contact plate (111), the current flows into the static contact (12) through the first contact plate (111), the two second contact plates (112) and the third contact plate (113) in turn, the current in the moving contact assembly (2) flows to the center of the moving contact bridge (21) through the moving contact (22) and the moving contact bridge (21), the current flow direction in the second contact plate (112) is opposite to that in the moving contact bridge (21).

8. The contact device according to any one of claims 1-7, characterized in that The distance between the moving contact bridge (21) and the static contact plate (11) gradually increases outward from the contact position of the moving contact (22) and the static contact (12).

9. Switched electrical apparatus, characterised in that The switch electric appliance comprises the contact device, and further comprises an arc extinguishing chamber (3), one of the two ends of the moving contact bridge (21) is provided with one arc extinguishing chamber (3), and the arc generated by the separation of the moving contact (22) and the static contact (12) is introduced into the arc extinguishing chamber (3).

10. The switchgear according to claim 9, characterized in that, The switch electric appliance further comprises an arc plate (4), the arc plate (4) is connected with the two arc extinguishing chambers (3), and the magnetic yoke (23) is arranged on the arc plate (4). The switch electric appliance further comprises an arc plate (4), the arc plate (4) is connected with the two arc extinguishing chambers (3), and the magnetic yoke (23) is arranged on the arc plate (4).

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