Contact device, electromagnetic switch, on-board charger and new energy vehicle

Abstract

A kind of contact device, electromagnetic switch, on-board charger and new energy vehicle.Contact device (100) includes base body (10), two static contacts (30) and moving contact assembly (50), the base body (10) has inner cavity (101), two the static contacts (30) are fixed on the base body (10) and extend into the inner cavity (101) of the base body (10), the moving contact assembly (50) includes push component (51) and moving contact (52), the push component (51) is movably arranged in the base body (10), the moving contact (52) is installed on the push component (51) and located in the inner cavity (101) of the base body (10), the push component (51) is used to drive the moving contact (52) movement, to realize the moving contact (52) and two the static contacts (30) contact or separate, wherein, the moving contact (52) includes N parallel contact blades (521), N is the integer greater than 1.So, the possibility that moving contact (52) is repelled when short-circuit large current is suffered is reduced, and the short-circuit resistance of contact device and electromagnetic switch is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric control devices, in particular to a contact device, an electromagnetic switch with the contact device, a vehicle-mounted charging machine and a new energy vehicle. BACKGROUND

[0002] The electromagnetic switch refers to an electric appliance capable of frequently closing, carrying and breaking normal current and specified overload current. Its working principle is to use the magnetic field generated by the current flowing through the coil to make the contact closed or opened to achieve the purpose of controlling the load. The electromagnetic switch usually includes a contactor and a relay.

[0003] When the moving contact and the static contact in the electromagnetic switch are in contact, the moving contact will be subjected to an electric repulsion generated by the current. Part of the electric repulsion is the Hall force generated by the contraction of the current flowing through the contact point between the moving contact and the static contact. The greater the current, the greater the Hall force generated. Thus, when the electric repulsion received by the moving contact is greater than the contact pressure received by the moving contact, the moving contact has the risk of being repelled.

[0004] In the field of new energy vehicles and the like, the short-circuit current of the system is continuously improved, which also means that the anti-short-circuit current capability of the electromagnetic switch is required to be higher and higher to reduce the risk of the moving contact being repelled. The existing electromagnetic switch improves the anti-short-circuit current capability of the electromagnetic switch by increasing the contact pressure or the electric repulsion compensation device and the like. However, such structure is still insufficient to resist the electric repulsion generated by a large short-circuit current (for example, more than 10KA), which will easily cause the moving contact to be repelled and cause explosion and fire, thereby causing a safety accident. SUMMARY

[0005] The embodiments of the present application disclose a contact device, an electromagnetic switch, a vehicle-mounted charging machine and a new energy vehicle capable of improving the anti-short-circuit current capability.

[0006] In a first aspect, the present application provides a contact device applied to an electromagnetic switch, comprising a base body, two static contacts and a moving contact assembly, the base body has an inner cavity, the two static contacts are fixed on the base body and extend into the inner cavity of the base body, the moving contact assembly comprises a pushing component and a moving contact, the pushing component is movably arranged in the base body, the moving contact is installed on the pushing component and located in the inner cavity of the base body, the moving contact comprises N parallel contact pieces, N is an integer greater than 1, and the N parallel contact pieces can be in contact with or separated from the two static contacts under the driving of the pushing component.

[0007] When the moving and static contacts are closed to conduct current, the moving contact will be subjected to an electric repulsion generated by the current, part of which is the Hall force F h , Wherein, μ0 is the magnetic permeability in vacuum, R is the radius of the moving contact, and r is the radius of the contact area between the moving contact and the static contact (i.e., the contact radius). It can be seen that, as the current I increases, the HOM force F h increases.

[0008] The contact device provided in the present application adopts a bridge-type double-breakpoint contact structure, and the moving contact includes N parallel contact pieces, the current flowing through each contact piece is Each contact piece is subjected to a HOM force F ′ h is greatly reduced, the possibility of the moving contact being repelled when subjected to a large short-circuit current is reduced, the short-circuit resistance of the contact device and the electromagnetic switch is improved, and the safety and reliability of the contact device and the electromagnetic switch are also improved.

[0009] The electromagnetic force compensation device in the prior art also saturates when the short-circuit current is large, so that the electromagnetic attraction no longer increases with the increase of the short-circuit current, which affects the short-circuit resistance of the contact device. In the present application, the moving contact includes N parallel contact pieces, which reduces the HOM force of the moving contact, and improves the short-circuit resistance of the contact device, which is also conducive to the miniaturization of the contact device.

[0010] According to the first aspect, in a first possible implementation manner of the first aspect, the moving contact assembly further includes a connecting component and a contact elastic member, the N parallel contact pieces are each provided with a first sliding hole, the connecting component is slidably arranged in the first sliding hole and fixedly connected with the pushing component, and the contact elastic member is located between the N parallel contact pieces and the pushing component, and the N parallel contact pieces can move towards or away from the static contact relative to the pushing component.

[0011] The contact elastic member is located between the N parallel contact pieces and the pushing component, and is used to provide an elastic force to the contact pieces. On the one hand, the contact elastic member ensures the contact pressure when the contact pieces contact the static contact, so that the contact pieces and the static contact maintain good contact; on the other hand, the contact elastic member also buffers the impact force between the moving contact and the static contact to a certain extent, reduces the possibility of damage to the moving contact and the static contact, and thus prolongs the service life of the electromagnetic switch.

[0012] In a second possible implementation manner of the first aspect or the first possible implementation manner of the first aspect, the pushing component comprises a push rod, an isolating piece and a contact bracket, the isolating piece is fixedly sleeved on one end of the push rod, the contact bracket is fixedly sleeved outside the isolating piece, N parallel contact pieces are arranged in the contact bracket, the connecting component is fixedly connected with the contact bracket, and the elastic piece is arranged between the isolating piece and the N parallel contact pieces.

[0013] When the moving contact and the stationary contact are in contact and conductive, the moving contact and the stationary contact form a high-voltage contact loop, and the isolating piece effectively isolates the high-voltage contact loop from other low-voltage parts in the electromagnetic switch, so that when the electromagnetic switch with the contact device switches a high-voltage DC load with a large current, the low-voltage part of the electromagnetic switch is not affected by the large current and high voltage, and damage caused by breakdown between high and low voltages is prevented, thereby improving the safety and reliability of the contact device.

[0014] In a third possible implementation manner of the first aspect or the first to second possible implementation manners of the first aspect, the moving contact assembly further comprises a compensation structure, the compensation structure comprises a moving magnetic conductor and a stationary magnetic conductor, the moving magnetic conductor is movably connected with the contact bracket, the stationary magnetic conductor is fixed on the contact bracket and located on a side of the contact piece away from the push rod, a working air gap is formed between the moving magnetic conductor and the stationary magnetic conductor, and the moving magnetic conductor and the stationary magnetic conductor can generate an electromagnetic attraction force based on a current flowing through the moving contact and the stationary contact when they are in contact, so that the moving magnetic conductor moves towards the stationary magnetic conductor.

[0015] When the moving contact and the stationary contact are in contact and conductive, the moving contact and the stationary contact form a high-voltage contact loop, and the isolating piece effectively isolates the high-voltage contact loop from other low-voltage parts in the electromagnetic switch, so that when the electromagnetic switch with the contact device switches a high-voltage DC load with a large current, the low-voltage part of the electromagnetic switch is not affected by the large current and high voltage, and damage caused by breakdown between high and low voltages is prevented, thereby improving the safety and reliability of the contact device.

[0016] In a fourth possible implementation manner of the first aspect or the first to third possible implementation manners of the first aspect, the movable magnetic conductor and the side wall part extending from the two ends of the bottom wall part form an opening slot together, the N parallel contact pieces are arranged in the opening slot, the bottom wall part is located between the contact pieces and the isolation piece, the side wall part is provided with a second sliding hole, the contact spring is arranged in the bottom wall part, the connecting part is slidingly arranged in the second sliding hole, and the movable magnetic conductor is movable relative to the contact pieces. The movable magnetic conductor wraps the N parallel contact pieces, facilitating assembly of the movable magnetic conductor and the N parallel contact pieces. Since the movable magnetic conductor is movable relative to the movable contact, the air gap distance of the working air gap that can be reduced is greater than the overtravel of the contact, which is beneficial to further reducing the air gap distance of the working air gap, thereby further improving the short-circuit current resistance of the contact device.

[0017] In a fifth possible implementation manner of the first aspect or the first to fourth possible implementation manners of the first aspect, the compensation structure further comprises an elastic piece, the elastic piece is arranged between the bottom wall part of the movable magnetic conductor and the N contact pieces, and the elastic piece helps the movable magnetic conductor to reset.

[0018] In a sixth possible implementation manner of the first aspect or the first to fifth possible implementation manners of the first aspect, the compensation structure further comprises a fixed support, the fixed support is fixed to the contact support, the static magnetic conductor is fixed to the fixed support, and the static magnetic conductor is located between the fixed support and the N parallel contact pieces. The static magnetic conductor is fixed to the contact support through the fixed support, facilitating assembly and disassembly of the static magnetic conductor.

[0019] In a seventh possible implementation manner of the first aspect or the sixth possible implementation manner of the first aspect, the contact piece is provided with a bearing sub-groove, the bearing sub-grooves of the N parallel contact pieces are communicated with each other to form a bearing groove, the contact spring is arranged between the pushing part and the inner wall of the bearing groove, in this way, the same contact spring can bear all the contact pieces, the elastic force is provided to each contact piece through the same contact spring, the contact pressure between each contact piece and the static contact is ensured, the number of contact springs is reduced, the structure of the movable contact assembly and the contact device is simplified, and assembly and disassembly are facilitated.

[0020] In an eighth possible implementation manner of the first aspect or the first to seventh possible implementation manners of the first aspect, the isolating piece comprises a connecting portion and a guiding portion, the connecting portion is fixedly sleeved on one end of the push rod and fixedly penetrates the contact support, the guiding portion is protruded on a side of the connecting portion away from the push rod, the elastic piece is sleeved on the guiding portion, and the guiding portion is used for guiding movement of the contact elastic piece relative to the contact support, thereby improving contact stability of each contact piece and the stationary contact.

[0021] In a ninth possible implementation manner of the first aspect or the first to eighth possible implementation manners of the first aspect, the connecting component comprises a contact shaft and two clamping pieces, each end of the contact shaft is provided with a clamping groove, the contact shaft penetrates the first sliding hole and the contact support, the clamping groove is located outside the contact support, and each clamping piece is clamped in the corresponding clamping groove, so that the contact shaft is fixed on the contact support in a clamping manner, thereby facilitating assembly and disassembly of the movable contact assembly.

[0022] In a second aspect, the application further provides an electromagnetic switch comprising a driving device and the contact device as described above, one end of the base body away from the stationary contact is fixedly connected with the driving device, and one end of the driving device away from the movable contact is connected with the pushing component of the contact device, so as to drive movement of the pushing component.

[0023] The electromagnetic switch provided in the second aspect adopts the bridge-type double-breakpoint contact structure, the movable contact comprises N parallel contact pieces, the magnetic force borne by each contact piece is greatly reduced, the possibility that the movable contact is repelled when bearing a large short-circuit current is reduced, the short-circuit resistance of the contact device and the electromagnetic switch is improved, and the safety and reliability of the contact device and the electromagnetic switch are also improved.

[0024] In a third aspect, the application further provides a vehicle-mounted charger comprising the electromagnetic switch as described above.

[0025] In a fourth aspect, the application further provides a new energy vehicle comprising the vehicle-mounted charger and a battery pack as described above, the battery pack is used for storing electric quantity input by the vehicle-mounted charger and is also used for inverting and discharging by the vehicle-mounted charger. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A structural block diagram of the new energy vehicle provided in the application is shown in the figure;

[0027] Figure 2 A top view of the electromagnetic switch provided in the first embodiment of the application is shown in the figure;

[0028] Figure 3 A sectional view of the electromagnetic switch shown in the figure along line A-A is shown in the figure; Figure 2 A sectional view of the electromagnetic switch shown in the figure along line A-A is shown in the figure;

[0029] Figure 4 This is a schematic diagram of the forces acting on the moving contact and the stationary contact when they are in contact.

[0030] Figure 5 for Figure 3 A three-dimensional assembly diagram of the moving contact assembly of the electromagnetic switch shown.

[0031] Figure 6 for Figure 3 An exploded perspective view of the moving contact assembly shown.

[0032] Figure 7 A cross-sectional view of the electromagnetic switch provided in the second embodiment of this application;

[0033] Figure 8 for Figure 7 A three-dimensional assembly diagram of the moving contact assembly is shown.

[0034] Figure 9 for Figure 7 Side view of the moving contact assembly shown;

[0035] Figure 10 For along Figure 8 The moving contact assembly shown is a cross-sectional view along line BB in one state;

[0036] Figure 11 For along Figure 8 The moving contact assembly shown is a cross-sectional view along line BB in another state;

[0037] Figure 12 This is a cross-sectional view of the moving contact assembly in one embodiment of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0039] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0040] In addition, in this application, the expression "and / or" includes any and all combinations of the associated listed terms. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0041] In this application, the expression including ordinal numbers such as "first" and "second" can modify elements. However, such elements are not limited by the above expression. For example, the above expression does not limit the order and / or importance of the elements. The above expression is only used to distinguish one element from other elements. For example, the first user equipment and the second user equipment indicate different user equipment, although the first user equipment and the second user equipment are both user equipment. Similarly, the first element can be called the second element without departing from the scope of the application, and similarly, the second element can also be called the first element.

[0042] When a component is referred to as "connected" or "accessed" to another component, it should be understood that another component can exist between the component and the other component. On the other hand, when a component is referred to as "directly connected" or "directly accessed" to another component, it should be understood that there is no component between them.

[0043] Please refer to Figure 1 The application provides an electromagnetic switch 900 applied to a new energy vehicle 500. The new energy vehicle 500 includes a vehicle-mounted charger 502 and a battery pack 503. The battery pack 503 is used to store the power input by the vehicle-mounted charger 502, and is also used to discharge through the vehicle-mounted charger 502. The vehicle-mounted charger 502 includes the electromagnetic switch 900, which is used to control current on-off, isolate power high voltage, and the like, so as to ensure normal work of the load or prevent the risk of electric shock. It can be understood that the new energy vehicle 500 can also include other necessary or unnecessary structures or modules, for example, a driving system, a braking system, a battery management system, and the like, which are not described here; the vehicle-mounted charger 502 can also include other necessary or unnecessary structures or modules, for example, an interface, and the like, which are not described here.

[0044] The electromagnetic switch in the embodiment of the application is further described below.

[0045] Please refer to Figure 2 The electromagnetic switch provided by the first embodiment of the application is a plan view. The electromagnetic switch 900 in the embodiment of the application refers to an electric appliance capable of frequently closing, carrying and opening normal current and specified overload current. Its working principle is to use the magnetic field generated by the current flowing through the coil to make the contact closed, so as to achieve the purpose of controlling the load. The electromagnetic switch usually includes an electromagnetic relay and a contactor. In the embodiment of the application, a direct current contactor is taken as an example for description.

[0046] Please refer toFigure 3 , Figure 3 For Figure 2 Figure 3 is a sectional view of the electromagnetic switch along the direction of A-A. The electromagnetic switch 900 includes a driving device 200 and a contact device 100 arranged on the driving device 200. The driving device 200 drives the moving iron core to move by the electromagnetic field generated by the coil to control the opening and closing of the contact device 100. The electromagnetic switch 900 in the embodiment is a so-called normally open contactor with the contacts being disconnected in the initial state. In other embodiments, the electromagnetic switch 900 can also be a so-called normally closed contactor with the contacts being connected in the initial state.

[0047] It can be understood that Figure 2 With Figure 3 The electromagnetic switch 900 shown in Figure 3 generally also includes a housing, for example, the contact device 100 and the driving device 200 are housed in a hollow square housing. The electromagnetic switch 900 in the embodiment of the application is a schematic diagram without a housing.

[0048] The driving device 200 includes a coil former 21, a coil 22, a yoke 23, a static iron core 24, a moving iron core 25, a sealing sleeve 26 and a reset elastic member 27. Specifically, the coil former 21 includes a main body part 211 in the form of a hollow cylinder, and the two ends of the main body part 211 in the axial direction protrude in the radial direction to form a circular flange part 212. Among them, the axial direction refers to the direction of the center axis of the cylinder, that is, the direction parallel to the center axis. The radial direction is perpendicular to the axial direction, that is, the radius or diameter direction of the end face circle of the cylinder.

[0049] The coil 22 is wound on the main body part 211 of the coil former 21 and located between the two flange parts 212 at both ends of the main body part 211. It can be understood that the two ends of the coil 22 are also connected with coil terminals (not shown in the figure). For example, the coil terminals can be made of conductive materials such as copper, so that the coil 22 can be energized through the coil terminals to drive the driving device 200.

[0050] The yoke 23 is composed of a magnetic material and surrounds the coil former 21. In the embodiment of the application, the yoke 23 is generally in the shape of a "mouth" character, which includes an upper cover plate 231, a side plate 232 and a bottom plate 233 connected in sequence. Among them, the upper cover plate 231, the side plate 232 and the bottom plate 233 are all in the form of rectangular plate structure, and the upper cover plate 231 and the bottom plate 233 correspond to the two flange parts 212 of the coil former 21 respectively. In an embodiment, the bottom plate 233 and the side plate 232 can be integrally formed, that is, the bottom plate 233 and a pair of side plates 232 can be continuously formed by bending a sheet.

[0051] The bottom plate 233 of the yoke 23 is formed with a through hole 233a in which a sealing sleeve 26 is fitted. Specifically, the through hole 233a can be formed by stamping, such that the portion of the bottom plate 233 that is stamped extends into the main body portion 211 of the coil former 21 to form a peripheral wall of the through hole 233a.

[0052] The static iron core 24 and the dynamic iron core 25 are arranged in the main body portion 211 of the coil former 21 in the axial direction of the main body portion 211. Specifically, the static iron core 24 is fixedly arranged at one end of the main body portion 211 and is close to the upper cover plate 231. When the coil 22 is energized, the static iron core 24 generates an attractive force due to magnetization, and the dynamic iron core 25 is driven to move in the direction of the static iron core 24 under the action of the attractive force. In this embodiment, the static iron core 24 and the dynamic iron core 25 are both substantially cylindrical.

[0053] The sealing sleeve 26 is arranged in the coil former 21 and surrounds the static iron core 24 and the dynamic iron core 25. In this embodiment, the sealing sleeve 26 is made of a non-magnetic material and has an open end 261. The flange portion 212 of the coil former 21 close to the upper cover plate 231 is formed with a circular annular support surface 212a, and the open end 261 of the sealing sleeve 26 is formed with an abutting portion 261a that protrudes in the radial direction. The support surface 212a is used to support and fix the abutting portion 261a, thereby preventing the sealing sleeve 26 from falling off.

[0054] In this embodiment, the outer diameter of the static iron core 24 and the dynamic iron core 25 is substantially the same as the inner diameter of the sealing sleeve 26. The static iron core 24 is arranged at the open end of the sealing sleeve 26, and the dynamic iron core 25 moves in the sealing sleeve 26. It can be understood that the movement range of the dynamic iron core 25 is from the end surface of the static iron core 24 away from the open end 261 to the space of the sealing sleeve 26 away from the upper cover plate 231.

[0055] In addition, a plug-in hole 231a is provided through the substantially central position of the upper cover plate 231 for the static iron core 24 to pass through, and the inner diameter of the plug-in hole 231a is smaller than the inner diameter of the sealing sleeve 26. The middle portion of the end of the static iron core 24 away from the dynamic iron core 25 protrudes in the axial direction of the static iron core 24 to form a plug-in portion 243. The plug-in portion 243 is installed in the plug-in hole 231a, thereby achieving the fixation and installation of the static iron core 24. It can be understood that the through hole 241 of the static iron core 24 penetrates the plug-in portion 243 and is used for plugging the contact device 100.

[0056] The reset elastic member 27 is clamped between the static iron core 24 and the dynamic iron core 25. The reset elastic member 27 is used to apply a driving force to the dynamic iron core 25 in the opposite direction to the attractive force generated by the static iron core 24, thereby enabling the dynamic iron core 25 to be driven to return to the initial position when the coil 22 is de-energized, i.e., to be driven to move to the end of the sealing sleeve 26 away from the contact device 100.

[0057] It should be noted that in the embodiment of the present application, the first abutting part 242 protruding towards the center side and reducing the aperture of the insertion hole 241 is arranged on the whole circumference of the middle part of the insertion hole 241 of the static iron core 24. The second abutting part 252 protruding towards the center side and reducing the aperture of the insertion hole 251 is arranged on the whole circumference of the bottom part of the insertion hole 251 of the moving iron core 25. One end of the reset elastic member 27 abuts against the first abutting part 242, and the other end of the reset elastic member 27 abuts against the second abutting part 252.

[0058] The contact device 100 comprises a base 10, two static contacts 30 and a moving contact assembly 50. The base 10 is in the shape of an open box, and the open side is arranged on the upper cover plate 231 of the driving device 200. The base 10 has an inner cavity 101. The top of the base 10 away from the opening is provided with two through holes 11, and the two static contacts 30 are respectively fixed to the base 10 through the corresponding through holes 11 and extend into the inner cavity 101. In the embodiment of the present application, the base 10 is made of heat-resistant material (such as ceramic). The static contact 30 is generally in the shape of a cylinder and is made of conductive material such as copper-based material. The moving contact assembly 50 is located in the base 10 and one end is mounted on the driving device 200, so that the moving contact assembly 50 can be in contact or separated from the two static contacts 30 under the driving of the driving device 200.

[0059] The moving contact assembly 50 comprises a pushing part 51, a moving contact 52, a connecting part 53 and a contact elastic member 55. One end of the pushing part 51 is located in the base 10 and the other end is mounted on the moving iron core 25, so that the pushing part 51 can move in the base 10 under the driving of the moving iron core 25.

[0060] The moving contact 52 is movably mounted on the pushing part 51 through the connecting part 53, and is used to contact or separate from the static contact 30 under the pushing action of the pushing part 51. The contact elastic member 55 is clamped between the moving contact 52 and the pushing part 51, and is used to provide an elastic force to the moving contact 52. On the one hand, the contact elastic member 55 ensures that there is enough contact pressure when the moving contact 52 contacts the static contact 30; on the other hand, the contact elastic member 55 buffers the impact force between the moving contact 52 and the static contact 30 to a certain extent when they contact, reduces the possibility of damage to the moving contact 52 and the static contact 30, thereby prolonging the service life of the electromagnetic switch 900. In the embodiment, the contact elastic member 55 is a compression spring. It can be understood that the contact elastic member 55 can also be an elastic structure such as a metal spring.

[0061] In this embodiment, the positional relationship between the moving iron core 25 and the moving contact 52 is set such that the moving contact 52 is separated from the stationary contact 30 when the moving iron core 25 is in its initial position, and the moving contact 52 is in contact with the stationary contact 30 when the moving iron core 25 is in a position abutting against the stationary iron core 24. That is, when the coil 22 is not energized, the contact device 100 is open, and the two stationary contacts 30 are disconnected, and the moving contact 52 is separated from the stationary contact 30; when the coil 22 is energized, the moving contact 52 is in contact with the stationary contact 30, the contact device 100 is closed, and the two stationary contacts 30 are conductive.

[0062] In this embodiment, the contact device 100 adopts a bridge-type double-break contact structure. Two stationary contacts 30 are spaced apart along a first direction at the end of the base 10 furthest from the driving device 200. In the bridge-type double-break contact structure, when the moving contact is in contact with the two stationary contacts, i.e., when the moving and stationary contacts are closed and conducting current, the moving contact will experience an electrodynamic repulsive force generated by the current. For example... Figure 4 As shown, the electrodynamic repulsion consists of two parts: one is the Lorentz force F generated by the current flowing through the stationary contact on the current in the moving contact. L Secondly, the Holm force F generated by the contraction of the current at the contact point between the moving and stationary contacts. h Holmley F h The force F is directly proportional to the square of the current I, meaning the larger the current, the greater the Holm force F produced. h The larger it is, the more specific it is, as shown in formula (1).

[0063]

[0064] Among them, F h Let μ0 be the Holm force on the moving contact, which uses a single contact piece structure, μ0 be the permeability in vacuum, R be the radius of the moving contact, and r be the radius of the contact area between the moving and stationary contacts (i.e., the contact radius). As the current I increases, for example, during a short circuit, when the electrodynamic repulsive force on the moving contact exceeds the contact pressure, the moving contact may be repelled, potentially leading to safety accidents such as explosions.

[0065] To address the aforementioned issues and improve the short-circuit current withstand capability of the electromagnetic switch 900, in this embodiment, the moving contact 52 includes N parallel contact pieces 521, where N is an integer greater than 1. Under the action of the pushing component 51, the N parallel contact pieces 521 can contact or separate from the two stationary contacts 30. Please refer to [reference needed]. Figure 5 and Figure 6 ,in Figure 5 for Figure 3 A three-dimensional assembly diagram of the moving contact assembly of the electromagnetic switch in the diagram; Figure 6 for Figure 5An exploded perspective view of the moving contact assembly. In this embodiment, the value of N is 2. Since the moving contact 52 includes N parallel contact pieces 521, that is, the moving contact 52 includes N contact piece structures. Let the total current flowing through the moving contact 52 be I, and the current flowing through each contact piece 521 be a fraction of the total current I of the moving contact 52. According to formula (1), the Holm force F on each contact piece 521 can be obtained. ′ h for This reduces the Holm force on the moving contact 52, lowers the likelihood of the moving contact 52 being repelled when subjected to a large short-circuit current, and thus improves the short-circuit withstand capability of the contact device 100 and the electromagnetic switch 900.

[0066] In this embodiment, the contact piece 521 extends along a first direction (i.e., the length direction of the contact piece 521 is the first direction, such as...). Figure 5 (as shown in the X direction), N contact pieces 521 along the second direction (as shown in the X direction), Figure 5 The N contact pieces 521 are arranged and contacted in the Y direction (as shown) to achieve parallel connection. Under the drive of the drive device 200, the driving component 51 can drive the N parallel contact pieces 521 along a third direction (such as the Y direction). Figure 5 The movement (in the Z direction shown) allows any two of the three directions—first, second, and third—to be perpendicular to each other, enabling N parallel contact pieces 521 to contact or separate from two stationary contacts 30. It is understood that the first and second directions are not limited to being perpendicular, nor are the second and third directions, nor are the third directions perpendicular to the first direction. It is also understood that the N contact pieces 521 can be connected in parallel via wires or other means, which are not limited here.

[0067] N parallel contact pieces 521 are each provided with a first sliding hole 5211. The connecting member 53 slides through the first sliding hole 5211, so that the contact piece 521 can move relative to the pushing member 51 in a third direction. The first sliding hole 5211 is an oblong hole extending in a third direction. The travel distance of the moving contact 52 in the third direction is the contact overtravel. The extension length of the first sliding hole 5211 in the third direction limits the contact overtravel of the moving contact 52. One end of the contact piece 521 near the driving device 200 is provided with a support sub-groove 5213. The support sub-grooves 5213 of the N parallel contact pieces 521 are interconnected to form a support groove 5215. The contact elastic member 55 abuts against the inner wall of the pushing member 51 and the support groove 5215. In this way, the same contact elastic element 55 can abut against all the contact pieces 521, and provide elastic force to each contact piece 521 through the same contact elastic element 55, ensuring the contact pressure between each contact piece 521 and the stationary contact 30, reducing the number of contact elastic elements 55 used, simplifying the structure of the moving contact assembly 50 and the contact device 100, and facilitating assembly and disassembly.

[0068] When the coil 22 is energized, the moving contact 52 is in contact with the static contact 30, and the contact piece 521 is pressed by the static contact 30 and can move along the first sliding hole 5211 towards the direction away from the static contact 30, preventing the contact piece 521 from being damaged by hard collision with the static contact 30. The contact spring 55 can ensure the contact pressure between the contact piece 521 and the static contact 30. When the coil 22 is de-energized, the moving contact 52 is separated from the static contact 30, and the contact piece 521 returns to the initial position in the first sliding hole 5211 due to the elastic effect of the contact spring 55.

[0069] In the embodiment, the number of the first sliding holes 5211 is one, and the first sliding hole 5211 is located at the middle position of the contact piece 521. The number of the resisting sub-slots 5213 on the contact piece 521 is two, and the two resisting sub-slots 5213 are arranged in the first direction with a spacing, and the first sliding hole 5211 is located between the two resisting sub-slots 5213. The number of the contact springs 55 is two, and the two contact springs 55 correspond to the two resisting sub-slots 5213 one by one, so that the elastic force acting on each part of the N parallel contact pieces 521 is balanced.

[0070] It can be understood that the number of the resisting sub-slots 5213 on the contact piece 521, the number of the first sliding holes 5211, the number of the connecting components 53, and the number of the contact springs 55 are not limited. For example, the number of the resisting sub-slots 5213 on the contact piece 521 is one, the number of the first sliding holes 5211 on the contact piece 521 is two, the resisting sub-slot 5213 is located between the two first sliding holes 5211, the two connecting components 53 correspond to the two first sliding holes 5211 one by one, and one contact spring 55 is arranged between the pushing component 51 and the inner wall of the resisting sub-slot 5213. In addition, the way of arranging the contact spring 55 on the contact piece 521 is not limited, and the resisting sub-slot 5213 can be omitted. For example, a protruding column is arranged on the side of the contact piece 521 facing the driving device 200, and the contact spring 55 is sleeved on the protruding column.

[0071] The pushing component 51 includes a pushing rod 511, an isolation piece 513, and a contact bracket 515. The pushing rod 511 is movably arranged in the insertion hole 241 of the static core 24, and one end of the pushing rod 511 is fixed in the insertion hole 251 of the moving core 25. The isolation piece 513 is fixedly sleeved on the end of the pushing rod 511 away from the moving core 25. The isolation piece 513 is made of electrically insulating material and is used to maintain good electrical insulation between the pushing rod 511 and the N parallel contact pieces 521. The contact bracket 515 is fixedly sleeved outside the isolation piece 513 and is used to carry the N parallel contact pieces 521. The N parallel contact pieces 521 are arranged in the contact bracket 515. The connecting component 53 is fixedly connected with the contact bracket 515, and the contact spring 55 is arranged between the isolation piece 513 and the N parallel contact pieces 521.

[0072] When the moving contact 52 is in contact with the static contact 30, the coil 22 is in low voltage, and the moving contact 52 and the static contact 30 form a high-voltage contact loop. Since the push rod 511 and the N parallel contact pieces 521 are electrically insulated by the isolation piece 513, the high-voltage contact loop is completely isolated from the low-voltage coil 22. When the electromagnetic switch 900 switches a large-current, direct-current high-voltage load, the low-voltage coil 22 of the electromagnetic switch 900 is not affected by the large current and high voltage, thereby preventing the safety problem caused by breakdown between high and low voltages, and improving the safety and reliability of the contact device 100 and the electromagnetic switch 900.

[0073] The isolation piece 513 includes a connecting portion 5131 and a guiding portion 5135. The connecting portion 5131 is fixedly sleeved on one end of the push rod 511 and fixedly penetrates the contact support 515, and is used to realize the fixed connection between the push rod 511 and the contact support 515. The guiding portion 5135 is protruded on the side of the connecting portion 5131 away from the first connecting portion 5131, and the contact elastic piece 55 is sleeved on the guiding portion 5135. The guiding portion 5135 is used to guide the movement of the contact elastic piece 55, and improve the contact stability of each contact piece 521 and the static contact 30. It can be understood that the structure of the isolation piece 513 is not limited, for example, the isolation piece 513 can omit the guiding portion 5135, and the isolation piece 513 can electrically isolate the push rod 511 and the moving contact 52. In the embodiment, the isolation piece 513 is made of plastic, and the push rod 511 and the contact support 515 are connected with the plastic isolation piece 513 to form the pushing member 51 by injection molding or other ways, and are isolated from each other by the plastic isolation piece 513. It can be understood that the isolation piece 513 is not limited to be made of plastic, and can also be made of other insulating materials, and the isolation piece 513, the push rod 511 and the contact support 515 are not limited to be fixedly connected by injection molding process.

[0074] The contact support 515 is substantially a U-shaped frame. The contact support 515 includes a bottom wall portion 5150 and side wall portions 5151 bent and extended from both ends of the bottom wall portion 5150. The bottom wall portion 5150 and the side wall portions 5151 surround a receiving groove 5153. The connecting portion 5131 of the isolation piece 513 penetrates the bottom wall portion 5150. The side wall portions 5151 are provided with mounting holes 5155, and the connecting member 53 is fixedly connected with the mounting holes 5155. The N parallel contact pieces 521 penetrate the receiving groove 5153, and the contact elastic piece 55 is received in the receiving groove 5153. The structure of the contact support 515 is simple, and the assembly and disassembly of the contact pieces 521 and the contact support 515 are facilitated. It can be understood that the structure of the contact support 515 is not limited, for example, the contact support 515 can omit the receiving groove 5153, and the contact support 515 can bear the N parallel contact pieces 521 of the moving contact 52.

[0075] The connecting component 53 comprises a contact shaft 531 and two clamping members 533. Each end of the contact shaft 531 is provided with a clamping groove 5311. The contact shaft 531 is arranged in the accommodating groove mounting hole 5155 and the first sliding hole 5211. The clamping groove 5311 is exposed to the mounting hole 5155 and located outside the contact support 515. The clamping member 533 is clamped in the clamping groove 5311 and used to prevent the contact shaft 531 from being separated from the contact support 515, thereby fixing the contact shaft 531 on the contact support 515. The contact shaft 531 is fixed on the contact support 515 in a clamping manner, which is beneficial to facilitate the assembly and disassembly of the movable contact assembly 50. It can be understood that the number of the connecting component 53 can be two or more, the number of the mounting hole 5155 on the side wall of the accommodating groove 5153 corresponds to the number of the connecting component 53, and the number of the first sliding hole 5211 corresponds to the number of the connecting component 53; the connecting component 53 is not limited to comprising the contact shaft 531 and the two clamping members 533, that is, the connecting component 53 is not limited to being mounted on the contact support 515 in a clamping manner.

[0076] When the movable contact assembly 50 is assembled, the isolating piece 513 is sleeved on the end of the push rod 511 away from the movable core 25, the contact support 515 is fixedly sleeved on the isolating piece 513, the contact elastic member 55 is sleeved on the guide portion 5135, the contact shaft 531 is arranged through the mounting hole 5155 of the contact support 515 and the first sliding hole 5211 of each contact piece 521, the end of the contact elastic member 55 away from the isolating piece 513 is clamped into the abutting groove 5215, and the clamping member 533 is clamped into the clamping groove 5311, so that the assembly of the movable contact assembly 50 is completed. It can be understood that the assembly sequence of the movable contact assembly 50 is only exemplary and does not constitute a limitation on the present application.

[0077] When the electromagnetic switch 900 is in the initial state, the movable contact 52 is not in contact with the static contact 30. After the coil 22 is powered on, the static core 24 generates an attractive force due to magnetization, and under the action of the attractive force of the static core 24, the movable core 25 moves towards the static core 24. The push rod 511 is driven by the movable core 25 to move towards the static contact 30, and the N parallel contact pieces 521 of the movable contact 52 are in contact with the static contact 30. The movable contact assembly 50 and the electromagnetic switch 900 provided by the present application, the movable contact 52 comprises N parallel contact pieces 521, even if a large short-circuit current (for example, more than 15 KA) appears between the movable contact 52 and the static contact 30, the homopolar force on a single contact piece 521 is very small, so that the homopolar force on the movable contact 52 is very small, thus reducing the possibility of the movable contact 52 being repelled, which is beneficial to improve the safety and reliability of the electromagnetic switch 900.

[0078] It should be noted that in the embodiments of the present application, the sealing sleeve 26, the upper cover plate 231 and the base body 10 form a common sealing chamber.

[0079] It is understood that the connecting component 53 can be omitted, and each contact piece 521 of the moving contact 52 can be directly connected to the pushing component 51. In one embodiment, a contact device applied to an electromagnetic switch includes a base, two stationary contacts and a moving contact assembly. The base has an inner cavity. The two stationary contacts are fixed at one end of the base at intervals and extend into the inner cavity of the base. The moving contact assembly includes a pushing component and a moving contact. The pushing component is movably disposed in the base. The moving contact is mounted on the pushing component and located in the inner cavity of the base. The moving contact includes N contact pieces connected in parallel, where N is an integer greater than 1. Under the drive of the pushing component, the N contact pieces connected in parallel can contact or separate from the two stationary contacts.

[0080] Please see Figure 7 , Figure 7 This is a cross-sectional view of the electromagnetic switch provided in the second embodiment of this application. The difference between this electromagnetic switch and the one provided in the first embodiment is that the moving contact assembly further includes a compensation structure 57, which generates an electromagnetic force to counteract part of the electrodynamic repulsion force experienced by the moving contact 52, further improving the short-circuit withstand capability of the electromagnetic switch.

[0081] Please refer to the following: Figure 8 , Figure 9 The compensation structure 57 includes a moving magnetic conductor 571, a fixed bracket 572, and a stationary magnetic conductor 573. The moving magnetic conductor 571 is slidably sleeved on the contact shaft 531 of the connecting component 53 and housed within the contact bracket 515. The fixed bracket 572 is fixed to the contact bracket 515 and located on the side of the contact piece 521 opposite to the push rod 511. The fixed bracket 572 is made of a non-magnetic material. The stationary magnetic conductor 573 is fixed to the fixed bracket 572 and located between the N parallel contact pieces 521 and the fixed bracket 572. A working air gap 501 is formed between the stationary magnetic conductor 573 and the moving magnetic conductor 571. The contact elastic element 55 passes through the moving magnetic conductor 571 and abuts against the contact piece 521 and the isolator 513.

[0082] Please see Figure 10 , Figure 10 The contact piece 521 of the moving contact 52 is not connected to the stationary contact ( Figure 10 (The diagram is omitted) When in contact, the contact piece 521 and the moving magnetic body 571 are in their initial positions.

[0083] Please see Figure 11 , Figure 11 For the moving contact 52, the contact piece 521 and the stationary contact ( Figure 11The state diagram when the contact is omitted) When the contact piece 521 of the moving contact 52 is in contact with the static contact, it is moved towards the direction of the push rod 511 by the pressure of the static contact. When the short-circuit current flows through the moving contact 52 and the two static contacts 30, an electromagnetic force is generated to attract the static magnetic conductor 573 and the moving magnetic conductor 571 based on the current, and then the static magnetic conductor 573 and the moving magnetic conductor 571 are attracted to each other, thereby offsetting part of the electric repulsion force on the moving contact 52. Specifically, when the short-circuit current is generated, the short-circuit current generates an electromagnetic attraction force F in the electromagnetic loop formed by the static magnetic conductor and the moving magnetic conductor (for example Figure 7 The electromagnetic attraction force F is proportional to the square of the current, the air gap area S of the working air gap, and inversely proportional to the square of the air gap distance δ of the working air gap, and the specific formula is as follows:

[0084] F∝I 2 *S / δ 2 , formula (2)

[0085] As can be seen from the above formula (2), the attraction force between the magnetic conductors can be increased by increasing the air gap area between the working air gaps or reducing the air gap distance of the working air gap. When the moving magnetic conductor 571 moves towards the static magnetic conductor 573, the air gap distance of the working air gap 501 becomes smaller, and the electromagnetic attraction force F becomes larger, thereby offsetting part of the Hall force on the moving contact 52. The moving contact structure of the N parallel contact pieces 521 combined with the compensation structure 57 greatly improves the short-circuit resistance of the contact device 100 and the electromagnetic switch 900.

[0086] More specifically, the moving magnetic conductor 571 is generally in the shape of a U. The moving magnetic conductor 571 includes a bottom wall part 5710 and side wall parts 5711 bent and extended from both ends of the bottom wall part 5710, and the bottom wall part 5710 and the side wall parts 5711 together enclose a slot 5713. The N parallel contact pieces 521 are arranged in the slot 5713, i.e. the moving magnetic conductor 571 wraps the N parallel contact pieces 521, which facilitates the assembly of the moving magnetic conductor 571 and the N parallel contact pieces 521. The side wall of the slot of the side wall part 5711 is provided with a second sliding hole 5717, and the contact shaft 531 is slidingly arranged in the second sliding hole 5717.

[0087] The stroke of the contact piece 521 moving along the third direction is a contact overstroke. Since the moving magnetic conductor 571 is capable of moving relative to the moving contact 52, the working air gap 501 is capable of reducing the air gap distance greater than the contact overstroke, which is beneficial to further reduce the air gap distance of the working air gap 501, thereby further improving the short-circuit current resistance of the contact device. The moving magnetic conductor 571 wraps the contact piece 521 and is installed with the contact piece 521 through the contact shaft 531, and the moving magnetic conductor 571 is capable of moving up and down when subjected to electromagnetic force to adjust the working air gap 501 between the moving magnetic conductor 571 and the static magnetic conductor 573. The contact device increases the compensation structure 57, and the electromagnetic attraction generated by the moving magnetic conductor 571 offsets part of the contact electrodynamic repulsion. The working air gap of the compensation structure 57 can be automatically adjusted. Since the working air gap is capable of reducing the air gap distance greater than the contact overstroke, the compensation force is greater than the compensation force provided by the existing contact device.

[0088] It can be understood that the moving magnetic conductor 571 can be fixed with the contact piece 521, that is, the moving magnetic conductor 571 and the contact piece 521 form a movable part that moves relative to the contact support 515, so that the working air gap is capable of reducing the air gap distance equal to the contact overstroke.

[0089] It can be understood that the fixed support 572 can be omitted, and the static magnetic conductor 573 can be directly fixed on the contact support 515. In an embodiment, the compensation structure includes a moving magnetic conductor and a static magnetic conductor, the moving magnetic conductor is slidably sleeved on the contact support, the static magnetic conductor is fixed on the contact support and located on the side of the contact piece away from the push rod, the working air gap is formed between the static magnetic conductor and the moving magnetic conductor, and the electromagnetic attraction is generated between the moving magnetic conductor and the static magnetic conductor based on the current flowing through when the moving contact and the static contact are in contact, so that the moving magnetic conductor moves towards the static magnetic conductor.

[0090] In an embodiment, referring to Figure 12 , the compensation structure further includes an elastic member 577, the elastic member 577 abuts between the bottom wall part 5710 of the moving magnetic conductor 571 and the contact piece 521, and is used for resetting the moving magnetic conductor 571.

[0091] The above is the implementation of the embodiment of the application. It should be noted that for those skilled in the art, without departing from the principle of the application, some improvements and refinements can be made, which are also considered as the protection scope of the application.

Claims

1. A contact device for an electromagnetic switch, characterized in that The connector comprises a base, two static contacts and a movable contact assembly. The base has an inner cavity. The two static contacts are fixed at one end of the base and extend into the inner cavity of the base. The movable contact assembly comprises a pushing member, a movable contact and a contact spring. The pushing member movably penetrates the base. The movable contact is mounted on the pushing member and located in the inner cavity of the base. The movable contact comprises N parallel contact pieces, wherein N is an integer greater than 1. The N parallel contact pieces can be in contact with or separated from the two static contacts under the driving of the pushing member. The contact spring is located between the N parallel contact pieces and the pushing member. The movable contact assembly further comprises a connecting member. The N parallel contact pieces are each provided with a first sliding hole. The connecting member slidably penetrates the first sliding hole and is fixedly connected with the pushing member. The N parallel contact pieces can move towards or away from the static contacts relative to the pushing member.

2. The contact device of claim 1, wherein The pushing member comprises a push rod, a spacer and a contact support. The spacer is fixedly sleeved on one end of the push rod. The contact support is fixedly sleeved outside the spacer. The N parallel contact pieces penetrate the contact support. The connecting member is fixedly connected with the contact support. The contact spring is abutted between the spacer and the N parallel contact pieces. The spacer is used to keep the push rod and the N parallel contact pieces electrically insulated.

3. The contact device of claim 2, wherein, The movable contact assembly further comprises a compensation structure. The compensation structure comprises a movable magnetic conductor and a static magnetic conductor. The movable magnetic conductor is movably connected with the contact support. The static magnetic conductor is fixed on the contact support and located on a side of the contact piece away from the push rod. The static magnetic conductor and the movable magnetic conductor form a working air gap therebetween. The movable magnetic conductor and the static magnetic conductor can generate an electromagnetic force based on the current flowing through the movable contact and the static contact when the movable contact is in contact with the static contact, so that the movable magnetic conductor moves towards the static magnetic conductor.

4. The contact device of claim 3, wherein, The movable magnetic conductor is accommodated in the contact support. The movable magnetic conductor comprises a bottom wall portion and side wall portions which are bent and extended from both ends of the bottom wall portion. The bottom wall portion and the side wall portions jointly enclose a slot. The N parallel contact pieces penetrate the slot. The bottom wall portion is located between the contact piece and the spacer. The side wall portions are provided with second sliding holes. The contact spring penetrates the bottom wall portion. The connecting member slidably penetrates the second sliding holes. The movable magnetic conductor can move relative to the contact piece.

5. The contact device of claim 4, wherein, The compensation structure further comprises a spring. The spring is abutted between the bottom wall portion of the movable magnetic conductor and the N contact pieces.

6. The contact device of claim 3, wherein, The compensation structure further comprises a fixed support. The fixed support is fixed on the contact support. The static magnetic conductor is fixed on the fixed support. The static magnetic conductor is located between the fixed support and the N parallel contact pieces.

7. The contact device according to any one of claims 2-6, characterized in that The contact piece is provided with an abutting sub-groove. The abutting sub-grooves of the N parallel contact pieces are communicated with each other to form an abutting groove. The contact spring is abutted between the spacer and the inner wall of the abutting groove.

8. The contact device according to any one of claims 2-6, characterized in that The isolating piece is provided with a guide part on the side away from the push rod, and the elastic piece is sleeved on the guide part.

9. An electromagnetic switch comprising a drive device and a contact device according to any one of claims 1 to 8, characterized in that The base is fixedly connected with the driving device at the end away from the static contact, and the driving device is connected with the pushing part of the contact device at the end away from the moving contact, for driving the pushing part to move.

10. An on-board charger, characterized by, The electromagnetic switch comprises the electromagnetic switch according to claim 9.

11. A new energy vehicle, characterized in that, The battery pack is used for storing the electric quantity input by the on-board charger and is also used for inverting and discharging through the on-board charger.

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