Pre-charging direct current contactor and use method thereof

Abstract

The invention discloses a pre-charging direct-current contactor and a using method thereof, and relates to the technical field of contactors, and the pre-charging direct-current contactor comprises a base which is provided with a static contact piece; a core rod is arranged in the center of the magnetic circuit assembly, and the core rod penetrates through the base; the main contact piece assembly is arranged at the upper end part of the core rod in a sleeving manner; the auxiliary contact piece assembly is arranged at the upper end part of the core rod in a sleeving manner, and a through cavity is formed in the top surface of the auxiliary contact piece assembly; the two ends of the elastic sheet abut against the auxiliary contact sheet assembly. According to the pre-charging direct current contactor, the technical problem that the contact resistance is increased after an anti-melting contact material is connected with a capacitive load for multiple times due to the fact that an existing contactor is directly connected with the load is solved, firstly, the auxiliary contact piece assembly is connected with the capacitive load to solve the influence of the capacitive load, and then the main contact piece assembly is in contact with the static contact piece to be connected into a main loop. Therefore, the contact resistance after the main contact piece assembly is connected to the main loop is not affected, and the stability of the contact resistance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of contactors, and in particular to a pre-charged DC contactor and a use method thereof. Background Art

[0002] At present, battery packs, inverters, energy storage, electronic controls, hydraulic power units, etc. in the DC market often experience short-term, high-current capacitive loads at the moment of connection due to the nature of the subsequent loads.

[0003] The anti-melting contact material used in the existing contactor increases the contact resistance after connecting the capacitive load multiple times, which is prone to abnormal heating. On the other hand, the contactor in the prior art solves the influence of the capacitive load by connecting a pre-charging resistor. This design requires timing design on the circuit, which has a high design cost, and the product volume of this solution is large and difficult to miniaturize. Therefore, a pre-charged DC contactor and a method of using the same are proposed to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a pre-charged DC contactor and a method of using the same, which solves the technical problem that the existing contactor directly connects the load, and the anti-melting contact material used increases the contact resistance after multiple connections with the capacitive load, causing abnormal heating of the contactor.

[0005] To achieve the above object, the present invention provides a pre-charged DC contactor, comprising:

[0006] A base, on which a static contact piece is arranged;

[0007] A magnetic circuit assembly is disposed below the base, a core rod is disposed at the center of the magnetic circuit assembly, and the core rod penetrates the base;

[0008] A main contact piece assembly, sleeved and arranged on the upper end of the core rod;

[0009] A secondary contact piece assembly is sleeved on the upper end of the core rod, and the secondary contact piece assembly is located below the primary contact piece assembly, and a through cavity is arranged on the top surface of the secondary contact piece assembly, and the through cavity is used to pass through the primary contact piece assembly;

[0010] The elastic sheet is arranged on the top surface of the main contact sheet assembly, and the two ends of the elastic sheet abut against the auxiliary contact sheet assembly.

[0011] Preferably, the auxiliary contact piece assembly includes: an auxiliary contact piece and a first contact point arranged on the bottom surface of both ends of the auxiliary contact piece, and the main contact piece assembly includes: a main contact piece and a second contact point arranged on the bottom surface of both ends of the main contact piece, the first contact point and the second contact point are both located directly above the static contact piece, and the first contact point and the second contact point can both abut against the static contact piece.

[0012] Preferably, the outer peripheral side surface of the core rod is sleeve-connected with a limiting member, and the top surface of the limiting member can abut against the bottom surface of the auxiliary contact piece assembly.

[0013] Preferably, two limit frame groups are symmetrically arranged on the top surface of the base, each of the limit frame groups includes two symmetrically arranged vertical poles, the inner side surfaces of the vertical poles abut against the outer side surfaces of the auxiliary contact pieces, a limit channel is arranged between the two vertical poles, and the two end portions of the limit member are located in the limit channel.

[0014] Preferably, the elastic sheet is in an arc shape as a whole, and two legs are respectively provided at two ends of the elastic sheet, and the legs abut against the top surface of the auxiliary contact sheet assembly.

[0015] Preferably, two folded edges are symmetrically arranged at the edge of the top surface of the secondary contact piece, and the folded edges abut against two side surfaces of the elastic piece.

[0016] Preferably, a limiting groove is provided between the two supporting legs at the same end of the elastic sheet, and the inner side surface of the limiting groove abuts against the side surface of the main contact sheet assembly.

[0017] Preferably, an elastic component is arranged at the upper end of the core rod, and the elastic component comprises: an upper isolation washer and a lower isolation washer are sequentially sleeved from top to bottom, a supporting spring is arranged between the upper isolation washer and the lower isolation washer, and the bottom surface of the lower isolation washer abuts against the top surface of the main contact piece assembly.

[0018] Preferably, an annular limiting groove is provided on the bottom surface of the upper isolation gasket and the top surface of the lower isolation gasket, and the annular limiting groove is clamped and connected to the supporting spring.

[0019] Correspondingly, the technical solution of the present invention further provides a method for precharging a DC contactor, which is applied to the precharging DC contactor described in any one of the above items, comprising:

[0020] Controlling the magnetic circuit assembly to drive the core rod to move downward relative to the base, the core rod drives the auxiliary contact piece assembly and the main contact piece assembly to move downward synchronously until the auxiliary contact piece assembly contacts the static contact piece, and the auxiliary contact piece assembly connects the capacitive load;

[0021] The magnetic circuit assembly is controlled to drive the core rod to continue to move downward relative to the base, the auxiliary contact piece assembly maintains contact with the static contact piece, and the core rod drives the main contact piece assembly to continue to move downward, and the main contact piece assembly passes through the through cavity until the main contact piece assembly contacts the static contact piece and the contact is closed.

[0022] Compared with the above background technology, the present invention provides a pre-charged DC contactor, which has the following beneficial effects:

[0023] (1) The present invention sets a main contact piece assembly and an auxiliary contact piece assembly at the upper end of the core rod, firstly makes the auxiliary contact piece assembly contact the static contact piece to connect the capacitive load, and then makes the main contact piece assembly contact the static contact piece to connect the main circuit, so that the auxiliary contact piece assembly connects the capacitive load first, solves the influence of the capacitive load, and thus does not affect the contact resistance after the main contact piece assembly is connected to the main circuit, increases the stability of the contact resistance, and effectively prevents the contactor from abnormally heating. The method of using the pre-charged DC contactor adopted in the present invention also has the above beneficial effects.

[0024] (2) The present invention makes the two ends of the elastic sheet abut against the auxiliary contact sheet assembly, so that the auxiliary contact sheet assembly and the main contact sheet assembly have a certain height difference in the longitudinal direction, and the auxiliary contact sheet assembly can float up and down relative to the main contact sheet assembly, thereby realizing the connection timing control of the main contact sheet assembly and the auxiliary contact sheet assembly, effectively reducing the circuit design cost of the contactor, and having better stability. On the other hand, by setting a through cavity on the top surface of the auxiliary contact sheet assembly, the main contact sheet assembly can pass through the through cavity, so that the main contact sheet assembly and the auxiliary contact sheet assembly have a certain overlapping height in the longitudinal height, so as to improve the space utilization rate of the overall contactor in the longitudinal height, reduce the overall volume of the contactor, and meet the miniaturization design requirements of the contactor. The method of using the pre-charged DC contactor adopted in the present invention also has the above beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0026] FIG1 is a three-dimensional structural diagram of a pre-charged DC contactor provided in an embodiment of the present invention;

[0027] FIG2 is a cross-sectional schematic diagram of a base and a magnetic circuit assembly provided by an embodiment of the present invention;

[0028] FIG3 is an exploded schematic diagram of the pre-charged DC contactor provided in an embodiment of the present invention after the base and the magnetic circuit assembly are hidden.

[0029] Specifically, 1-base; 101-static contact piece; 2-magnetic circuit assembly; 201-reset spring; 3-core rod; 301-annular limit part; 4-main contact piece assembly; 401-main contact piece; 402-second contact point; 5-auxiliary contact piece assembly; 501-auxiliary contact piece; 502-folded edge; 503-first contact point; 504-through cavity; 6-elastic piece; 601-support foot; 602-limiting groove; 7-limiting piece; 701-matching part; 702-connecting part; 8-limiting frame group; 9-elastic member; 901-upper isolation gasket; 902-lower isolation gasket; 903-support spring. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] As shown in FIG. 1 , FIG. 2 and FIG. 3 , in order to achieve the above-mentioned purpose, the present invention provides a pre-charged DC contactor, comprising: a base 1 and a main contact piece assembly 4 and an auxiliary contact piece assembly 5 arranged on the base 1 .

[0033] The base 1 is provided with a static contact piece 101 . Specifically, two notches are symmetrically provided on the top surface of the base 1 , and a static contact piece 101 is installed in each notch.

[0034] A magnetic circuit assembly 2 is provided below the base 1, and a core rod 3 is provided at the center of the magnetic circuit assembly 2. The core rod 3 penetrates the base 1, wherein the magnetic circuit assembly 2 is slidably connected to the core rod 3. The magnetic circuit assembly 2 can provide electromagnetic attraction to the core rod 3 to drive the core rod 3 to move downward relative to the base 1.

[0035] It should be noted that an annular limiting portion 301 is integrally provided in the middle part of the core rod 3, the bottom surface of the annular limiting portion 301 is connected to the reset spring 201, and the bottom end of the reset spring 201 is connected to the magnetic circuit assembly 2. In the initial state, the electromagnetic suction force provided by the magnetic circuit assembly 2 is equal to the elastic force of the reset spring 201, and at this time, the core rod 3 remains stationary relative to the base 1; when the electromagnetic suction force provided by the magnetic circuit assembly 2 is less than the elastic force of the reset spring 201, the core rod 3 moves upward relative to the base 1 under the support of the reset spring 201 until the electromagnetic suction force provided by the magnetic circuit assembly 2 is equal to the elastic force of the reset spring 201; when the electromagnetic suction force provided by the magnetic circuit assembly 2 is greater than the elastic force of the reset spring 201, the core rod 3 overcomes the force of the reset spring 201 under the attraction of the electromagnetic suction force and moves downward relative to the base 1 until the electromagnetic suction force provided by the magnetic circuit assembly 2 is equal to the elastic force of the reset spring 201.

[0036] A secondary contact sheet assembly 5 is slidably arranged below the main contact sheet assembly 4, and a through cavity 504 is arranged on the top surface of the secondary contact sheet assembly 5. The through cavity 504 is used to pass through the main contact sheet assembly 4. The through cavity 504 arranged on the top surface of the secondary contact sheet assembly 5 allows the main contact sheet assembly 4 and the secondary contact sheet assembly 5 to have a certain overlapping height in the longitudinal height, so as to improve the space utilization rate of the overall contactor in the longitudinal height, and the contactor has a better integration in the longitudinal direction. At the same time, the increase in the contacts avoids the increase in the lateral volume of the contactor, thereby effectively controlling the overall volume of the contactor and meeting the miniaturized design requirements of the contactor.

[0037] Moreover, the through cavity 504 coincides with the horizontal projection plane of the main contact piece assembly 4, and the inner side surface of the through cavity 504 can slide to cooperate with the circumferential side surface of the main contact piece assembly 4, so that the through cavity 504 can be used to limit the main contact piece assembly 4 to prevent the main contact piece assembly 4 from rotating relative to the static contact piece 101, thereby further improving the stability of the main contact piece assembly 4 when in contact with the static contact piece 101, and further improving the stability of the main contact piece assembly 4 after being connected to the main circuit.

[0038] In addition, an elastic sheet 6 is provided on the top surface of the main contact sheet assembly 4, and both ends of the elastic sheet 6 abut against the auxiliary contact sheet assembly 5. By abutting both ends of the elastic sheet 6 against the auxiliary contact sheet assembly 5, it is ensured that the auxiliary contact sheet assembly 5 can float up and down relative to the main contact sheet assembly 4. When the auxiliary contact sheet assembly 5 is not in contact with the static contact sheet 101, the auxiliary contact sheet assembly 5 is in a position away from the main contact sheet assembly 4, so as to ensure that the auxiliary contact sheet assembly 5 is first connected to the capacitive load, and then the main contact sheet assembly 4 is contacted with the static contact sheet 101 to connect to the main circuit, so that the auxiliary contact sheet assembly 5 is first connected to the capacitive load, the influence of the capacitive load is solved, and the contact resistance of the main contact sheet assembly 4 after being connected to the main circuit is not affected, and the stability of the contact resistance is increased. After the auxiliary contact sheet assembly 5 contacts the static contact sheet 101 and the main contact sheet assembly 4 gradually approaches the static contact sheet 101, the auxiliary contact sheet assembly 5 can always maintain contact with the static contact sheet 101, thereby ensuring the stability of the auxiliary contact sheet assembly 5 when the capacitive load is connected.

[0039] Furthermore, by abutting the two ends of the elastic sheet 6 against the auxiliary contact sheet assembly 5, a certain height difference exists between the main contact sheet assembly 4 and the auxiliary contact sheet assembly 5 in the longitudinal direction, and the auxiliary contact sheet assembly 5 can float up and down relative to the main contact sheet assembly 4, thereby realizing the connection timing control of the main contact sheet assembly 4 and the auxiliary contact sheet assembly 5, effectively reducing the circuit design cost of the contactor and improving the stability.

[0040] During use, when the contacts need to be closed, the control magnetic circuit assembly 2 drives the core rod 3 to move downward relative to the base 1, and the core rod 3 drives the auxiliary contact piece assembly 5 and the main contact piece assembly 4 to move downward synchronously until the auxiliary contact piece assembly 5 contacts the static contact piece 101, and the auxiliary contact piece assembly 5 connects the capacitive load; the control magnetic circuit assembly 2 drives the core rod 3 to continue to move downward relative to the base 1, the auxiliary contact piece assembly 5 maintains contact with the static contact piece 101, and the core rod 3 drives the main contact piece assembly 4 to continue to move downward, and the main contact piece assembly 4 passes through the through cavity 504 until the main contact piece assembly 4 contacts the static contact piece 101, and the main contact piece assembly 4 is connected to the main circuit, and the contacts are closed.

[0041] It should be noted that, in the case where the capacitive load has a small impact on the device and the duration is very short, such as battery packs, hydraulic power units, electronic controls, etc., the secondary contact piece assembly 5 is directly used to directly connect the capacitive load. In the case where the capacitive load has a large impact on the device and the duration is very long, such as frequency converters and energy storage devices, a resistor with a certain resistance value can be connected in series with the secondary contact piece assembly 5 and then the capacitive load is connected to control the pre-charge current and reduce the impact of the capacitive load on the device.

[0042] In one embodiment of the present invention, the auxiliary contact assembly includes: an auxiliary contact piece 501 and a first contact 503 arranged on the bottom surface of both ends of the auxiliary contact piece 501, and the main contact assembly includes: a main contact piece 401 and a second contact 402 arranged on the bottom surface of both ends of the main contact piece 401, the first contact 503 and the second contact 402 are both located directly above the static contact piece 101, the first contact 503 abuts the static contact piece 101 to connect the auxiliary contact piece 501 to the capacitive load, and the second contact 402 abuts the static contact piece 101 to connect the main contact piece 401 to the main circuit. Even if the first contact 503 is ablated by the capacitive load, it does not affect the contact between the second contact 402 and the static contact piece 101. It should be noted that there is a certain height difference between the second contact 402 and the first contact 503 in the longitudinal direction.

[0043] In one embodiment of the present invention, the outer peripheral side surface of the core rod 3 is sleeved and connected to the limit member 7, and the top surface of the limit member 7 can abut the bottom surface of the auxiliary contact assembly. Specifically, the limit member 7 is fixedly connected to the core rod 3 and is used to support the auxiliary contact piece assembly 5. When the core rod 3 is in an upper position relative to the base 1, the limit member 7 can limit the auxiliary contact piece assembly 5 to make it leave the static contact piece 101, so as to ensure the normal contact and disconnection between the first contact 503 and the static contact piece 101.

[0044] In addition, two limit frame groups 8 are symmetrically arranged on the top surface of the base 1, and each limit frame group 8 includes two symmetrically arranged vertical poles, and the inner side surfaces of the vertical poles abut against the outer side surfaces of the auxiliary contact piece 501, so as to limit the auxiliary contact piece 501 so that it cannot rotate relative to the core rod 3 with the axis of the core rod 3 as the axis, thereby ensuring that the first contact 503 can be accurately docked with the static contact piece 101, and a limit channel is arranged between the two vertical poles, and the limit channel is consistent with the axial direction of the core rod 3. The two end portions of the limit member 7 are located in the limit channel. In the process of the core rod 3 driving the limit member 7 to move upward, the two end portions of the limit member 7 can be limited to always be in the limit channel, thereby preventing the limit member 7 from rotating.

[0045] In one embodiment of the present invention, the limiting member 7 includes: a matching portion 701 and a connecting portion 702, the matching portion 701 is in a strip shape, and the two ends of the matching portion 701 are located in the limiting channel, the connecting portion 702 is a sleeve, a first through hole is provided on the top surface of the main contact piece 401, a second through hole is provided on the top surface of the elastic piece 6, and a third through hole is provided on the top surface of the auxiliary contact piece 501, and the sleeve is successively penetrated through the third through hole, the second through hole and the first through hole from bottom to top to fix the main contact, the auxiliary contact piece 501 and the elastic piece 6. It should be noted that the main contact, the auxiliary contact piece 501 and the elastic piece 6 can move up and down relative to the sleeve along the axial direction of the core rod 3.

[0046] In one embodiment of the present invention, the elastic sheet 6 is in an arc shape as a whole, and the concave surface of the elastic sheet 6 faces the base 1. Specifically, the top surface of the middle part of the elastic sheet 6 is set as a plane, and the top surface of the elastic sheet 6 fits the bottom surface of the main contact sheet 401 to ensure that the elastic sheet 6 can be stably fixed on the bottom surface of the main contact sheet 401. The two ends of the elastic sheet 6 elastically abut the auxiliary contact sheet assembly 5, wherein two legs 601 are symmetrically arranged at the two ends of the elastic sheet 6, and the legs 601 extend in a direction close to the auxiliary contact sheet 501, and the legs 601 abut the top surface of the auxiliary contact assembly. Preferably, the end of the legs 601 close to the auxiliary contact sheet 501 is warped to ensure that the legs 601 can stably hold the auxiliary contact sheet assembly 5.

[0047] In one embodiment of the present invention, two folded edges 502 are symmetrically arranged at the edge of the top surface of the auxiliary contact piece 501. The folded edges 502 are integrally arranged with the auxiliary contact piece 501, and the folded edges 502 extend toward the top of the auxiliary contact piece 501. The folded edges 502 abut against the two side surfaces of the elastic piece 6, so that the elastic piece 6 cannot rotate relative to the auxiliary contact piece 501, thereby improving the docking accuracy when the auxiliary contact piece 501 contacts the static contact piece 101.

[0048] In addition, a limiting groove 602 is arranged between the two legs 601 at the same end of the elastic sheet 6. The limiting groove 602 is U-shaped as a whole. The inner side surface of the limiting groove 602 abuts against the side surface of the main contact sheet assembly 4. The main contact sheet 401 can be limited by the limiting groove 602 to prevent the main contact sheet 401 from rotating relative to the elastic sheet 6, so that the main contact sheet 401, the elastic sheet 6 and the auxiliary contact sheet 501 are always kept relatively still relative to the static contact sheet 101 on the horizontal projection plane, thereby improving the docking accuracy when the main contact sheet 401 and the static contact sheet 101 are in contact.

[0049] In one embodiment of the present invention, an elastic component 9 is provided at the upper end of the core rod 3, and an elastic component 9 is provided at the upper end of the core rod 3. The upper end of the core rod 3 is sleeved with a main contact piece assembly 4, and the main contact piece assembly 4 is located below the elastic component 9. It should be noted that the elastic component 9 itself has a certain elastic expansion and contraction function, ensuring that when the main contact piece assembly 4 contacts the static contact piece 101, the elastic component 9 can provide a certain elastic pressure to the main contact piece assembly 4, thereby improving the stability of the main contact piece assembly 4 when contacting the static contact piece 101.

[0050] Specifically, the elastic member 9 includes: an upper isolation gasket 901 and a lower isolation gasket 902 are sequentially sleeved from top to bottom, a support spring 903 is arranged between the upper isolation gasket 901 and the lower isolation gasket 902, and the bottom surface of the lower isolation gasket 902 abuts against the top surface of the main contact piece assembly 4, wherein the elastic member 9 as a whole serves as the first elastic part, mainly providing elastic pressure for the main contact piece assembly 4, and the elastic sheet 6 serves as the second elastic part, mainly providing elastic pressure for the auxiliary contact piece assembly 5, ensuring that the first contact point 503 and the second contact point 402 can both stably contact the static contact piece 101, so that the main contact piece assembly 4 can be well connected to the main circuit, and the auxiliary contact piece assembly 5 can be well connected to the capacitive load.

[0051] In addition, an annular limiting groove 602 is provided on the bottom surface of the upper isolation gasket 901 and the top surface of the lower isolation gasket 902, and the support spring 903 is connected by being clamped through the annular limiting groove 602 to form a stable limit for the support spring 903, so that the upper isolation gasket 901, the lower isolation gasket 902 and the support spring 903 are stably connected, thereby ensuring the overall stability of the elastic component 9.

[0052] The method for using the pre-charged DC contactor adopted in the present invention specifically includes the following steps: in the initial state, the first contact 503 and the second contact 402 are not in contact with the static contact piece 101. When the contacts need to be closed, the magnetic circuit component 2 is controlled to drive the core rod 3 to move downward relative to the base 1, and the core rod 3 drives the auxiliary contact piece 501 and the main contact piece 401 to move downward synchronously until the first contact 503 on the auxiliary contact piece 501 contacts the static contact piece 101, and the auxiliary contact piece component 5 is connected to the capacitive load to solve the influence of the capacitive load; the magnetic circuit component 2 is controlled to continue to drive the core rod 3 to move downward relative to the base 1, the first contact 503 on the auxiliary contact piece 501 maintains contact with the static contact piece 101, the core rod 3 drives the main contact piece 401 to continue to move downward, and the main contact piece 401 passes through the through cavity 504 until the second contact 402 on the main contact piece 401 contacts the static contact piece 101, and the main contact piece component 4 is connected to the main circuit.

[0053] In summary, the auxiliary contact piece assembly 5 is first contacted with the static contact piece 101, and the auxiliary contact piece assembly 5 is first connected to the capacitive load to solve the influence of the capacitive load, and then the main contact piece assembly 4 is contacted with the static contact piece 101 to connect to the main circuit, thereby not affecting the contact resistance of the main contact piece assembly 4 after connecting to the main circuit, increasing the stability of the contact resistance, and preventing the contactor from easily overheating.

[0054] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0055] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A pre-charged DC contactor, characterized in that: include: A base, on which a static contact piece is arranged; A magnetic circuit assembly is disposed below the base, a core rod is disposed at the center of the magnetic circuit assembly, and the core rod penetrates the base; A main contact piece assembly, sleeved and arranged on the upper end of the core rod; A secondary contact piece assembly is sleeved on the upper end of the core rod, and the secondary contact piece assembly is located below the primary contact piece assembly, and a through cavity is arranged on the top surface of the secondary contact piece assembly, and the through cavity is used to pass through the primary contact piece assembly; The elastic sheet is arranged on the top surface of the main contact sheet assembly, and the two ends of the elastic sheet abut against the auxiliary contact sheet assembly.

2. A pre-charged DC contactor according to claim 1, characterized in that: The auxiliary contact piece assembly includes: an auxiliary contact piece and a first contact point arranged on the bottom surface of both ends of the auxiliary contact piece, and the main contact piece assembly includes: a main contact piece and a second contact point arranged on the bottom surface of both ends of the main contact piece, the first contact point and the second contact point are both located directly above the static contact piece, and the first contact point and the second contact point can both abut against the static contact piece.

3. A pre-charged DC contactor according to claim 1, characterized in that: The outer peripheral side surface of the core rod is sleeve-connected with a limiting piece, and the top surface of the limiting piece can abut against the bottom surface of the auxiliary contact piece assembly.

4. A pre-charged DC contactor according to claim 3, characterized in that: Two limit frame groups are symmetrically arranged on the top surface of the base, each of the limit frame groups includes two symmetrically arranged vertical poles, the inner side surfaces of the vertical poles abut against the outer side surfaces of the auxiliary contact pieces, a limit channel is arranged between the two vertical poles, and the two end portions of the limit member are located in the limit channel.

5. A pre-charged DC contactor according to claim 1, characterized in that: The elastic sheet is in an arc shape as a whole, and two legs are respectively arranged at two ends of the elastic sheet, and the legs abut against the top surface of the auxiliary contact sheet assembly.

6. A pre-charged DC contactor according to claim 5, characterized in that: Two folded edges are symmetrically arranged at the edge of the top surface of the auxiliary contact piece, and the folded edges abut against two side surfaces of the elastic piece.

7. A pre-charged DC contactor according to claim 6, characterized in that: A limiting groove is arranged between the two supporting legs at the same end of the elastic sheet, and the inner side surface of the limiting groove abuts against the side surface of the main contact sheet assembly.

8. A pre-charged DC contactor according to any one of claims 1 to 7, characterized in that: An elastic component is arranged at the upper end of the core rod, and the elastic component comprises: an upper isolation washer and a lower isolation washer are sequentially sleeved from top to bottom, a supporting spring is arranged between the upper isolation washer and the lower isolation washer, and the bottom surface of the lower isolation washer abuts against the top surface of the main contact piece assembly.

9. A pre-charged DC contactor according to claim 8, characterized in that: The bottom surface of the upper isolation gasket and the top surface of the lower isolation gasket are both provided with an annular limiting groove, and the annular limiting groove is clamped and connected to the supporting spring.

10. A method for using a pre-charged DC contactor, applied to the pre-charged DC contactor according to any one of claims 1 to 9, characterized in that: The method for using the pre-charged DC contactor includes: Controlling the magnetic circuit assembly to drive the core rod to move downward relative to the base, the core rod drives the auxiliary contact piece assembly and the main contact piece assembly to move downward synchronously until the auxiliary contact piece assembly contacts the static contact piece, and the auxiliary contact piece assembly connects the capacitive load; The magnetic circuit assembly is controlled to drive the core rod to continue to move downward relative to the base, the auxiliary contact piece assembly maintains contact with the static contact piece, and the core rod drives the main contact piece assembly to continue to move downward, and the main contact piece assembly passes through the through cavity until the main contact piece assembly contacts the static contact piece and the contact is closed.

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