Direct current contactor with pre-charging function

Abstract

The invention relates to the field of contactors, and discloses a direct current contactor with a pre-charging function, which comprises a shell and an iron cup assembly, a retainer is fixedly mounted in the shell, the iron cup assembly is sleeved in the retainer, and a pre-charging assembly for forming a pre-charging loop is arranged between the retainer and the shell. The pre-charging assembly comprises a resistance wire fixedly wound on the outer surface of the holder, and through winding of the resistance wire based on the holder, the occupied space in the shell is reduced, and the resistance value is provided. Through cooperation among the holder, the resistance wire, the shell and the like, an improved scheme of the pre-charging assembly comprising the wound resistance wire is provided, and structural innovation of the nested holder and the wound resistance wire is also provided, so that multiple technical problems of limited internal space, insulation, heat insulation, electromagnetic compatibility and the like of the direct current contactor shell are solved; and when being applied to switches of battery packs and electric drive positions of industrial vehicles, the switch has relatively high practicability.

Description

Technical Field

[0001] This invention relates to the field of contactor technology, and in particular to a DC contactor with a pre-charge function. Background Technology

[0002] To address the issue of inrush current during closing, a small number of customers in the market currently use circuit solutions without a pre-charge circuit (such as...). Figure 1 As shown in the figure, at the moment the main positive contactor and the main negative contactor are closed, the DC power supply charges the equivalent capacitance of the circuit, and a large instantaneous current flows through the circuit, which can easily cause the contactor contacts to burn and stick.

[0003] Currently, the vast majority of customers in the market use circuit solutions with pre-charge circuits (such as...). Figure 2 As shown, a pre-charge contactor, a pre-charge resistor, and a circuit connection are connected in parallel across the two ends of the main positive contactor to form a pre-charge circuit. Before the main circuit is connected, the main negative contactor and the pre-charge contactor are closed first. The DC power supply charges the capacitor through the pre-charge resistor with current limiting. At this time, the circuit is small and does not damage the contactor. After charging to a certain voltage, the main positive contactor is closed again. At this time, the capacitor voltage is close to the DC power supply voltage, and no excessive current is generated.

[0004] However, the circuit scheme of the above-mentioned pre-charge circuit has low system integration and requires additional configuration of independent pre-charge contactors and pre-charge resistors, which occupies a lot of installation space and cannot meet the requirements of scenarios with strict space requirements such as new energy vehicles. Its disadvantages are more obvious for compact and micro electric vehicles, so there are certain limitations in its use.

[0005] Therefore, it is necessary to provide a DC contactor with pre-charge function to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to provide a DC contactor with a pre-charge function to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, a DC contactor with pre-charge function is designed that can effectively reduce installation space occupation and ensure sufficient resistance value.

[0008] Based on the above ideas, the present invention provides the following technical solution: a DC contactor with pre-charge function, including a housing and an iron cup assembly. A retainer is fixedly installed inside the housing, and the iron cup assembly is sleeved inside the retainer. A pre-charge component for forming a pre-charge circuit is provided between the retainer and the housing. The pre-charge component includes a resistance wire fixedly wound on the outer surface of the retainer. By winding the resistance wire based on the retainer, the space occupied inside the housing is reduced and a resistance value is provided.

[0009] As a further aspect of the present invention: the pre-charge component also includes a circuit board fixedly installed inside the housing, the circuit board being electrically connected to a relay and a time chip inside the housing, and the two ends of the resistance wire being respectively connected to the two output terminals of the relay.

[0010] As a further aspect of the present invention: the circuit board controls the first closing of the relay to connect the resistance wire, the current is limited by the wound resistance wire, and then the main positive contactor is closed and the relay is disconnected.

[0011] As a further aspect of the present invention: the outer surface of the retainer is provided with an annular groove for winding the resistance wire, and the top of the retainer is provided with a lead-out groove communicating with the annular groove. A conductive terminal communicating with the resistance wire is fixedly installed inside the lead-out groove, and the conductive terminal is connected to the output terminal of the relay through an internal wire.

[0012] As a further aspect of the present invention: the number of conductive terminals is two, and the two conductive terminals are respectively fixedly connected to both ends of the resistance wire.

[0013] As a further embodiment of the present invention: one end of the resistance wire is connected to the conductive terminal, and the other end of the resistance wire is insulated and sealed. A lifting component protruding from the top of the iron cup assembly is slidably installed on the retainer. The lifting component abuts against the outer surface of the resistance wire on one hand, and is electrically connected to the output terminal of the relay through a flexible wire on the other hand.

[0014] As a further aspect of the present invention: the lifting assembly includes a slide mounted vertically on a retainer, and an abutment block is elastically connected to the surface of the slide block near the resistance wire by a spring. The abutment block tends to move towards the resistance wire under the action of the spring.

[0015] As a further aspect of the present invention: the contact block is made of conductive material, one end of which abuts against the outer surface of the resistance wire, and the other end is fixedly connected to the flexible wire. A vertical groove for placing the flexible wire is provided on the surface of the slide away from the resistance wire.

[0016] As a further aspect of the present invention: a locking bolt for limiting the slide is threaded onto the housing. The locking bolt is screwed into the front surface of the housing, slides along the iron cup assembly, and abuts against the surface of the slide.

[0017] As a further aspect of the present invention: an annular cavity for mounting the resistance wire is formed between the outer surface of the retainer and the inner wall of the housing, and a square cavity for mounting the circuit board is formed on the front side of the inner wall of the housing, and the annular cavity and the square cavity are connected to each other.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: by cooperating with the cage, resistance wire, housing and iron cup assembly, an improved solution for a pre-charge assembly including wound resistance wire is provided, eliminating the need for additional pre-charge resistors and pre-charge contactors, effectively reducing overall costs; and it provides a structural innovation of winding the resistance wire on the outer surface of the cage, which on the one hand ensures sufficient resistance value, thereby providing effective protection for the iron cup assembly, and on the other hand effectively reduces the space occupied in the housing. Without increasing the size of the DC contactor, the function of the pre-charge circuit is integrated, which greatly improves product reliability and simplifies system design, and has strong industrial application value.

[0019] Meanwhile, all pre-charge circuit functional components are integrated inside the housing. This breaks through the industry's conventional design concept that "pre-charge circuit functional components must be placed externally on one side of the housing" in existing circuit solutions with pre-charge circuits. It achieves a fully integrated design of the pre-charge components. Through the structural innovation of nested retainers and wound resistance wires, it solves multiple technical problems such as limited internal space of DC contactor housing, insulation and heat insulation, and electromagnetic compatibility. It has high practicality when applied to switches in battery packs and electric drive positions of industrial vehicles. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a circuit diagram of the present invention without a pre-charge circuit; Figure 2 This is a circuit diagram of the pre-charge circuit in this invention; Figure 3 This is a perspective view of the overall structure of the present invention; Figure 4 This is an exploded view of the overall structure of the present invention; Figure 5 This is a schematic diagram of the cage structure of the present invention; Figure 6 This is a schematic diagram of the housing and lifting assembly structure of the present invention; Figure 7 This is a schematic diagram of the cage and slide structure of the present invention; Figure 8 for Figure 7 Enlarged view of the structure at point A in the middle; Figure 9 This is a schematic diagram of the bracket and collar structure of the present invention; Figure 10 for Figure 9 Enlarged view of the structure at point B in the middle.

[0021] In the diagram: 1. Housing; 2. Iron cup assembly; 3. Cage; 4. Resistance wire; 5. Circuit board; 6. Relay; 7. Time chip; 8. Lifting assembly; 9. Locking bolt; 10. External wire; 201. Opening; 301. Annular groove; 302. Lead-out groove; 401. Conductive terminal; 801. Slide; 802. Contact block; 803. Flexible wire; 804. Vertical groove; 805. Curved surface; 8011. Bracket; 8012. Ring; 8013. Round head. Detailed Implementation

[0022] Example 1: Please see Figures 1 to 5 This invention provides a DC contactor with a pre-charge function. The pre-charge circuit is integrated into the DC contactor through a structural design, forming a pre-charge circuit system. This achieves a small system size, saves space, and reduces overall cost. Specifically, the DC contactor includes a housing 1. A retainer 3 is fixedly installed inside the housing 1. The retainer 3 has a ring-shaped design and houses a conventional epoxy contactor's iron cup assembly 2. The retainer 3 is fitted onto the lower part of the iron cup assembly 2. After the iron cup assembly 2 is assembled based on the housing 1, the position of the retainer 3 based on the housing 1 is also effectively fixed. The iron cup assembly 2 constructs the magnetic circuit, seals and extinguishes the arc, provides support and positioning, and shields against interference, ensuring reliable switching and a long lifespan for the DC contactor. This is a mature existing technology and will not be described in detail here.

[0023] Furthermore, such as Figure 4 As shown, a pre-charge assembly is provided between the cage 3 and the housing 1. This pre-charge assembly forms a pre-charge circuit to prevent adhesion caused by capacitive impact during the closing of the main positive contactor. Furthermore, it eliminates the need for additional pre-charge resistors and pre-charge contactors, resulting in a reduction in overall cost for the customer. Specifically, the pre-charge assembly includes a resistance wire 4 fixedly wound on the outer surface of the cage 3. By winding the resistance wire 4 on the outer surface of the cage 3, sufficient resistance value is ensured, and the space occupied within the housing 1 is effectively reduced, thus decreasing the system size.

[0024] Reference Figures 3 to 5 In this embodiment, preferably, the precharge component further includes a circuit board 5 fixedly installed inside the housing 1. The circuit board 5 is electrically connected to a relay 6 and a time chip 7 within the housing 1. The relay 6 can be used to control the on / off state of the precharge circuit, while the time chip 7 enables the circuit board 5 to have a timing or delay function, ensuring that the DC contactor always cuts off the current to the circuit board 5 within a set time, facilitating overall circuit control. The specific structure and application of the relay 6 and the time chip 7 are existing mature technologies and will not be described in detail here.

[0025] In this embodiment, the two ends of the resistance wire 4 wound on the outer surface of the cage 3 are respectively connected to the two output terminals of the relay 6, which are the fixed access terminals of the pre-charge circuit. When the DC contactor coil is energized, the circuit board 5 controls the relay 6 to close first, connecting the wound resistance wire 4. At this time, the equivalent capacitance of the circuit is charged and the current is limited by the wound resistance wire 4, so the current has a controllable and shock-free effect. After a certain delay (which can be set to 1 second) by the time chip 7, the main positive contactor is closed and the relay 6 is opened. At this time, the main circuit is officially turned on. At the moment of conduction, the voltage difference between the equivalent capacitance and the power supply is small, avoiding capacitive impact at the moment of closing the main positive contactor that could cause sticking.

[0026] Reference Figure 4 and Figure 5 In this embodiment, preferably: the outer surface of the retainer 3 is provided with an annular groove 301 for winding the resistance wire 4, and the top of the retainer 3 is provided with a lead-out groove 302 that communicates with the annular groove 301 through the vertical direction. Two conductive terminals 401 that are fixedly connected to both ends of the resistance wire 4 are fixedly installed in the lead-out groove 302. The conductive terminals 401 are connected to the output terminal of the relay 6 through internal wires (not shown in the figure).

[0027] Correspondingly, such as Figure 4 As shown, since the retainer 3 is located below the iron cup assembly 2 after assembly, the cover surface of the iron cup assembly 2 needs to have a corresponding opening 201. At this time, the external wire 10 can be introduced from the opening 201 and connected to the circuit board 5.

[0028] It should be noted that the retainer 3 forms an annular cavity for mounting the resistance wire 4 between the annular groove 301 and the inner wall of the housing 1. A square cavity for mounting the circuit board 5 is also formed on the front side of the inner wall of the housing 1. The annular cavity and the square cavity are connected to each other, facilitating the placement of internal wires. In the above structure, by installing the wound resistance wire 4 and the circuit board 5 in the annular cavity and square cavity of the housing 1 respectively, a pre-charge DC contactor with a pre-charge circuit function is formed.

[0029] It is understandable that the circuit scheme in this embodiment is similar to... Figure 2 The circuit scheme with a pre-charge circuit differs in that it incorporates... Figure 2 The pre-charge contactor and pre-charge resistor in the original design have been improved to a relay 6 and a resistance wire 4. Furthermore, the innovative structure of winding the resistance wire 4 on the outer surface of the cage 3 effectively reduces the installation space required, meeting the needs of scenarios with stringent space requirements, such as new energy vehicles. This advantage is particularly prominent for compact and micro electric vehicles.

[0030] In summary, by combining the cage 3, resistance wire 4, housing 1, and relay 6, an improved technical solution using relay 6 and resistance wire 4 is provided. This eliminates the need for additional pre-charge resistors and pre-charge contactors, effectively reducing overall costs. Furthermore, the innovative structure of winding resistance wire 4 onto the outer surface of the cage 3 ensures sufficient resistance, thus providing effective protection for the iron cup assembly 2. It also effectively reduces the space occupied within the housing 1. Without increasing the size of the DC contactor, the pre-charge circuit function is integrated, significantly improving product reliability and simplifying system design, demonstrating strong industrial application value.

[0031] In this embodiment, all precharge circuit functional components are integrated inside the housing 1. This breaks through the conventional industry design concept that "precharge circuit functional components must be externally placed on one side of the housing" in existing circuit solutions with precharge circuits. It achieves a fully integrated design with the wound resistance wire 4, relay 6, and time chip 7 built-in. Through the structural innovation of the nested retainer 3 and the wound resistance wire 4, it solves multiple technical problems such as limited internal space of the DC contactor housing 1, insulation and heat insulation, and electromagnetic compatibility. It has high practicality when applied to the switch of battery pack and electric drive position in industrial vehicles.

[0032] Example 2: Please see Figures 1 to 8 Based on Embodiment 1, considering that the resistance value of the resistance wire 4 on the outer surface of the retainer 3 is relatively fixed, the setting of the resistance wire 4 is further improved: at this time, one end of the resistance wire 4 is connected to the conductive terminal 401 in the lead-out groove 302, and the conductive terminal 401 is electrically connected to one of the output terminals of the relay 6 through the internal wire, which is the fixed access terminal of the pre-charge circuit; the other end of the resistance wire 4 is insulated and sealed, and is not connected to the electrical circuit, but only mechanically fixed.

[0033] Furthermore, such as Figure 6 As shown, a lifting assembly 8 protruding from the top of the iron cup assembly 2 is slidably mounted on the retainer 3. The lifting assembly 8 abuts against the outer surface of the resistance wire 4 on one hand, and is electrically connected to another output terminal of the relay 6 via a flexible wire 803 on the other hand, serving as the movable access terminal for the pre-charge circuit. Simultaneously, a locking bolt 9 is threaded onto the housing 1 to limit the lifting assembly 8, thereby improving its limiting effect. By moving the lifting assembly 8 up and down based on the retainer 3, the lifting assembly 8 abuts against different positions of the wound resistance wire 4, achieving the effect of quickly adjusting the resistance value of the resistance wire 4.

[0034] Reference Figures 6 to 8In this embodiment, preferably, the lifting assembly 8 includes a slide block 801 slidably mounted on the retainer 3. The slide block 801 can only slide up and down based on the retainer 3. The surface of the slide block 801 near the resistance wire 4 is elastically connected to an abutment block 802 by a spring (not shown in the figure). The abutment block 802 tends to move closer to the resistance wire 4 under the action of the spring. However, due to the structural limitations of the slide block 801, it will not be completely inserted into the gap of the winding resistance wire 4 when moving up and down along the resistance wire 4.

[0035] Among them, such as Figure 8 As shown, the contact block 802 is made of conductive material. One end of it abuts against the outer surface of the resistance wire 4, and the other end is fixedly connected to the flexible wire 803. Correspondingly, a vertical groove 804 for placing the flexible wire 803 can be opened on the surface of the slide block 801 away from the resistance wire 4 to avoid interference between the flexible wire 803 and the slide block 801 and the housing 1 due to squeezing and jamming.

[0036] In this embodiment, an insulating transparent plate (not shown in the figure) can be fixedly embedded on the housing 1 to meet the need for rapid observation of the position of the contact block 802.

[0037] Reference Figures 6 to 8 In this embodiment, preferably, the locking bolt 9 corresponds to the surface of the slide block 801 away from the resistance wire 4. When the housing 1 rotates and moves due to the threaded connection, it can lock the position of the slide block 801 from the side, thereby relatively fixing the position of the contact block 802. The locking bolt 9 passes through the iron cup assembly 2 and abuts against the surface of the slide block 801. Alternatively, the locking bolt 9 is threaded onto the top of the housing 1, and the locking bolt 9 rotates with the top of the slide block 801. When the housing 1 rotates, the locking bolt 9 can also drive the slide block 801 to move up and down, but this would significantly increase the size of the housing 1.

[0038] In use, first loosen the locking bolt 9 and slide the slide block 801 up and down based on the retainer 3. The slide block 801 drives the contact block 802 to move up and down and form abutment with the outer surface of the resistance wire 4 at different positions, while the flexible wire 803 can keep moving with it. The closer the slide block 801 is to the conductive terminal 401, the shorter the effective connection length and the smaller the resistance value. The closer it is to the other end that is insulated and sealed, the longer the effective length and the larger the resistance value. After adjusting to the target resistance value, the locking bolt 9 can be rotated in the opposite direction to lock the slide block 801.

[0039] Compared to Embodiment 1, by cooperating with structures such as slide block 801, flexible wire 803, retainer 3 and contact block 802, the contact block 802 moves up and down along the retainer 3 to abut against the outer surface of the resistance wire 4 at different positions, changing the effective conductive length of the resistance wire 4 connected to the pre-charge circuit, thereby adjusting the resistance wire 4 to different resistance values ​​without changing the material and wire diameter of the resistance wire 4 itself, and without occupying additional internal space of the housing 1.

[0040] This solution is directly compatible with the existing cage 3 and winding resistance wire 4 layout, without the need to replace or rewind the resistance wire 4, ensuring high overall applicability. Furthermore, the contact block 802 can effectively adapt to vibration conditions under the action of the spring, maintaining stable contact resistance even in vibration working environments, with no risk of loosening.

[0041] Meanwhile, the overall adjustment operation is convenient and can be completed quickly during the assembly and on-site operation and maintenance stages. It can match the optimal pre-charge parameters and adapt to practical scenarios with high resistance accuracy requirements, such as R&D debugging, customized vehicle models, and energy storage project debugging.

[0042] Example 3: Please see Figures 1 to 10 Based on Embodiment 2, considering that the contact area between the abutment block 802 and the winding resistance wire 4 is limited and can only move up and down, the slide block 801 is improved: at this time, the slide block 801 includes a bracket 8011 that slides up and down with the retainer 3 and is limited by a locking bolt 9. A collar 8012 is rotatably installed at the bottom of the bracket 8011, and a round head 8013 is rotatably installed inside the collar 8012. The abutment block 802 is slidably installed inside the round head 8013, and the spring is located inside the round head 8013.

[0043] Furthermore, a spiral groove (not shown in the figure) is provided on the inner wall of the housing 1 for the round head 8013 to slide. When the bracket 8011 slides up and down along the retainer 3, the round head 8013 can be driven to descend synchronously through the collar 8012. At this time, the round head 8013 moves synchronously along the spiral groove. In this embodiment, the spiral groove corresponds to the spiral state of the resistance wire 4 after winding, so that when the round head 8013 drives the contact block 802 to move along the spiral groove, the contact block 802 can always maintain contact with the outer surface of the resistance wire 4; correspondingly, an arc surface 805 can be provided on the surface of the contact block 802 near the resistance wire 4 to ensure the contact effect with the outer surface of the resistance wire 4.

[0044] Alternatively, the spiral groove can be formed on the outer surface of the retainer 3, that is, the spiral groove is located inside the resistance wire 4. In this case, it is only necessary to reverse the direction of the round head 8013, the contact block 802, the spring and the flexible wire 803. The solution is the same as the spiral groove installed on the inner wall of the housing 1, but the effective space of the retainer 3 can be further utilized, and the structure of the housing 1 can be adjusted to form a modular design of the retainer 3, so that the retainer 3 can meet the purpose of quick disassembly and maintenance.

[0045] When in use, when the locking bolt 9 is loosened and the bracket 8011 is slid up and down, the bracket 8011 drives the round head 8013 to move up and down through the collar 8012, and the spiral groove restricts the round head 8013 from moving along the spiral trajectory, so that the contact block 802 can always be in contact with the outer surface of the resistance wire 4, and the contact block 802 can contact the outer surface of the resistance wire 4 at different positions.

[0046] Compared to Embodiment 2, through the cooperation of structures such as bracket 8011, round head 8013, contact block 802 and spiral groove, when the bracket 8011 is slid up and down, the contact block 802 can move along the spiral trajectory and keep in contact with the outer surface of the resistance wire 4. At this time, the resistance value of the resistance wire 4 can be continuously adjusted steplessly, and there are no breaks in the adjustment process. The optimal pre-charge parameters can be accurately matched, and the high-precision resistance value requirements of different debugging scenarios can be further met.

[0047] The contact block 802 forms an effective contact with the outer surface of the resistance wire 4 through the arc surface 805. When it moves along the resistance wire 4 in a spiral trajectory, the contact block 802 can simultaneously scrape off the oxide layer and carbon deposits on the surface of the resistance wire 4, thereby maintaining a clean metal contact surface, reducing the resistance drift problem caused by the oxide layer and carbon deposits, and ensuring the long-term stable use of the DC contactor.

[0048] Meanwhile, the overall solution does not change the core layout of the original structure, so the adjustment method of the contact block 802 remains simple. While reducing the operating burden of the staff, the adjustment effect of the resistance wire 4 is further improved, making it more practical.

Claims

1. A DC contactor with pre-charge function, comprising a housing and an iron cup assembly, characterized in that, A retainer is fixedly installed inside the housing, and the iron cup assembly is sleeved inside the retainer. A pre-charge component for forming a pre-charge circuit is provided between the retainer and the housing. The pre-charge component includes a resistance wire fixedly wound on the outer surface of the retainer. By winding the resistance wire based on the retainer, the space occupied inside the housing is reduced and a resistance value is provided.

2. The DC contactor with pre-charge function according to claim 1, characterized in that, The precharge assembly also includes a circuit board fixedly installed inside the housing. The circuit board is electrically connected to a relay and a time chip inside the housing, and the two ends of the resistance wire are respectively connected to the two output terminals of the relay.

3. The DC contactor with pre-charge function according to claim 2, characterized in that, The circuit board first closes the relay to connect the resistance wire, which limits the current. Then, it closes the main positive contactor and disconnects the relay.

4. The DC contactor with pre-charge function according to claim 2, characterized in that, The outer surface of the cage is provided with an annular groove for winding the resistance wire. The top of the cage is provided with a lead-out groove that communicates with the annular groove. A conductive terminal that communicates with the resistance wire is fixedly installed inside the lead-out groove. The conductive terminal is connected to the output terminal of the relay through an internal wire.

5. The DC contactor with pre-charge function according to claim 4, characterized in that, The number of conductive terminals is two, and the two conductive terminals are fixedly connected to both ends of the resistance wire.

6. The DC contactor with pre-charge function according to claim 4, characterized in that, One end of the resistance wire is connected to a conductive terminal, and the other end of the resistance wire is insulated and sealed. A lifting component protruding from the top of the iron cup assembly is slidably installed on the cage. The lifting component abuts against the outer surface of the resistance wire on one hand, and is electrically connected to the output terminal of the relay through a flexible wire on the other hand.

7. The DC contactor with pre-charge function according to claim 6, characterized in that, The lifting assembly includes a slide mounted vertically on a retainer. A contact block is elastically connected to the surface of the slide near the resistance wire via a spring. Under the action of the spring, the contact block tends to move closer to the resistance wire.

8. The DC contactor with pre-charge function according to claim 6, characterized in that, The contact block is made of conductive material. One end of it abuts against the outer surface of the resistance wire, and the other end is fixedly connected to the flexible wire. A vertical groove for placing the flexible wire is opened on the surface of the slide away from the resistance wire.

9. The DC contactor with pre-charge function according to claim 6, characterized in that, The housing is threaded with a locking bolt for limiting the slide block. The locking bolt is screwed into the front surface of the housing, slides along the iron cup assembly, and abuts against the surface of the slide block.

10. The DC contactor with pre-charge function according to any one of claims 2-9, characterized in that, An annular cavity for mounting the resistance wire is formed between the outer surface of the cage and the inner wall of the housing. A square cavity for mounting the circuit board is formed on the front side of the inner wall of the housing, and the annular cavity and the square cavity are connected to each other.

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