Capacitance-resistant contact assembly of direct current contactor
By employing a dual-contact structure and an anti-sticking design using high-melting-point, ablation-resistant materials in the DC contactor, the current surge problem during capacitive connection of the DC contactor is solved, achieving efficient current carrying and protection, reducing cost and space occupation, and making it suitable for starting industrial vehicles and low-speed vehicles.
Patent Information
- Application Number
- CN202423266197.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing DC contactors cannot withstand capacitive surges far exceeding the rated current during capacitive connection, leading to contact sticking. Existing pre-charge circuit solutions are costly and bulky, resulting in unsatisfactory performance.
Design a DC contactor anti-capacitive contact assembly, which adopts a double contact structure and an anti-sticking sheet made of high melting point erosion-resistant material. By setting a step on the stationary contact and setting an anti-sticking sheet on the moving contact, the first contact can bear the large current, and the pre-charge circuit function is combined to avoid contact damage.
It enables DC contactors to directly handle instantaneous high currents of several times or even tens of times the rated current, protecting contact components, reducing costs and saving space, and is suitable for industries such as industrial vehicles and low-speed vehicle starting.
Smart Images
Figure CN223651328U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of DC contactor technology, and specifically to a DC contactor anti-capacitive contact assembly. Background Technology
[0002] A DC contactor is a type of contactor used in DC circuits, primarily to control the conduction of DC circuits (main circuits, control circuits, and excitation circuits, etc.).
[0003] Most of the contact structures used in the market are bridge-type normally open single contact structures. In industries where there is capacitive connection, such as starting industrial vehicles or low-speed vehicles, a large current far exceeding the rated current will appear at the moment of circuit connection. DC contactors cannot withstand the capacitive impact of the current far exceeding the rated current at the moment of connection, which can easily lead to electric shock and sticking, affecting the normal use of DC contactors.
[0004] To address the above issues, the current market solution is to add a pre-charge circuit to limit the starting current. Please refer to [link / reference]. Figure 2 , Figure 2 Area A is the pre-charge circuit, which consists of a pre-charge contactor and a current-limiting resistor. At the moment of connection, the pre-charge circuit and the main (-) circuit are opened first, and the equivalent capacitor is charged from the pre-charge circuit. When the voltage difference is small enough, the main (+) circuit is opened. In this way, no large current will pass through at the moment of connection. However, this method will increase the cost, and the pre-charge circuit will occupy a large volume in the DC contactor. The effect is still not ideal. Utility Model Content
[0005] In view of the shortcomings of the prior art described above, the purpose of this utility model is to provide a DC contactor capacitive contact assembly to solve the problems of high cost and large size of the prior art in which the method of adding a pre-charge circuit is used to limit the instantaneous current at startup.
[0006] To achieve the above and other related objectives, this utility model provides a DC contactor anti-capacitive contact assembly, including a stationary contact, a moving contact, and a driving mechanism. The driving mechanism drives the moving contact to make contact with the stationary contact to control the conduction of the circuit current.
[0007] The moving contact includes a first moving contact piece and a second moving contact piece superimposed on the first moving contact piece. A step is provided on the inner side of the lower end of the stationary contact. When the stationary contact and the moving contact are in contact, the stationary contact contacts the first moving contact piece and the second moving contact piece respectively through the lower end of the stationary contact piece and the step.
[0008] A first anti-sticking sheet is provided on the step, and a second anti-sticking sheet is provided on the second moving contact sheet. The first anti-sticking sheet and the second anti-sticking sheet first contact the conducting circuit before the stationary contact and the moving contact, so as to bear the large current at the moment of connection.
[0009] In one embodiment of the present invention, both the first anti-adhesion sheet and the second anti-adhesion sheet are made of a high melting point and ablation-resistant material.
[0010] In one embodiment of this utility model, the high melting point and ablation-resistant materials used to make the first and second anti-adhesion sheets include one or more of tungsten, copper tungsten, and copper tungsten carbide.
[0011] In one embodiment of this utility model, both the stationary contact and the moving contact are made of copper.
[0012] In one embodiment of this utility model, the driving mechanism includes:
[0013] The shaft has the first and second movable contact pieces mounted on its upper end.
[0014] A moving iron core, which is sleeved on the lower end of the shaft;
[0015] A magnetic conductive sheet is fitted above the moving iron core.
[0016] In one embodiment of the present invention, the contact assembly further includes a guide plate, a shaft passing through the guide plate, and a magnetic sheet mounted on the lower end of the guide plate.
[0017] In one embodiment of the present invention, a first contact spring is provided between the first movable contact piece and the guide plate, and a second contact spring is provided between the first movable contact piece and the second movable contact piece.
[0018] In one embodiment of this utility model, a reaction spring is provided between the moving iron core and the guide plate.
[0019] In one embodiment of the present invention, a retaining ring is sleeved at the lower end of the shaft, and the retaining ring is limited at the lower end of the moving iron core.
[0020] As described above, the DC contactor capacitive contact assembly of this utility model has the following beneficial effects:
[0021] This invention forms a double-contact structure by setting the moving contact as a double contact piece and setting a step on the stationary contact. Compared with the bridge-type moving contact single-contact structure currently used in the market, it can directly increase the contact head position inside the DC contactor, thereby increasing the current carrying capacity of the moving contact and improving the temperature rise performance. By setting anti-sticking plates on the moving contact piece at the upper end of the moving contact and on the step of the stationary contact, the two anti-sticking plates are in contact before the moving contact and the stationary contact come into contact. Relying on the high melting point and anti-ablation characteristics of the anti-sticking plates, they can withstand instantaneous large currents at the millisecond level, and can withstand instantaneous large currents of several times or even tens of times the rated current. Because the anti-sticking plates have a high melting point and are not easy to weld, the instantaneous current cannot damage the anti-sticking plates, thus achieving an anti-capacitive effect. Subsequently, the moving contact and the stationary contact come into contact to undertake the subsequent energizing function. At this time, the circuit voltage difference is very small, and there is almost no inrush current when the moving contact and the stationary contact are connected, thus protecting the contact assembly.
[0022] This invention, by changing the contact structure of the stationary and moving contacts and designing an anti-sticking sheet, integrates the pre-charge circuit function used in existing technologies into a DC contactor, achieving the function of resisting capacitive surges in the DC contactor. Furthermore, the product has a simple structural design, occupies almost no internal space of the DC contactor, does not require the use of electronic components to form a pre-charge circuit structure, and has low manufacturing costs. It can be used in industries where capacitive connection may occur, such as starting industrial vehicles and starting low-speed vehicles, to handle capacitive loads that far exceed the rated current at the moment of connection, and has good market application prospects. Attached Figure Description
[0023] Figure 1 The diagram shown is a structural schematic of this utility model.
[0024] Figure 2 The diagram shows an example of adding a precharge circuit to existing technology.
[0025] Figure 3 The diagram shown is a cross-sectional view of the present invention with the stationary contact removed.
[0026] Figure 4 The diagram shown is a three-dimensional structural schematic of the present invention with the stationary contact removed.
[0027] Figure 5 The diagram shown is an enlarged structural schematic of the stationary contact in this utility model.
[0028] Figure 6 Displayed as Figure 5 A structural diagram from another perspective.
[0029] Component designation explanation
[0030] 1. Stationary contact; 11. Step; 2. Moving contact; 21. First moving contact piece; 22. Second moving contact piece; 3. First anti-adhesion piece; 4. Second anti-adhesion piece; 5. Shaft; 6. Moving iron core; 7. Magnetic conductive piece; 8. Guide plate; 9. First contact spring; 10. Second contact spring; 12. Reaction spring; 13. Snap ring. Detailed Implementation
[0031] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.
[0032] Please see Figures 1 to 6 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of this invention, should still fall within the scope of the disclosed technical content. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.
[0033] Please see Figure 1 , Figures 3-6 This utility model provides a capacitive contact assembly for a DC contactor, including a stationary contact 1, a moving contact 2, and a driving mechanism. Both the stationary contact 1 and the moving contact 2 are made of copper. The copper material of the stationary contact 1 and the moving contact 2 ensures low internal resistance when the product is connected, allowing the contactor to maintain a low temperature rise during long-term energization. The driving mechanism includes a shaft 5, a moving iron core 6, and a magnetic sheet 7. The moving contact 2 is mounted on the upper end of the shaft 5, and the moving iron core 6 is sleeved on the lower end of the shaft 5. A retaining ring 13 is sleeved on the lower end of the shaft 5, limiting the movement of the moving iron core 6 and improving the reliability of the connection between the shaft 5 and the moving iron core 6. The magnetic sheet 7 is fitted above the moving iron core 6. The driving mechanism drives the moving contact 2 to move and contact the stationary contact 1 to control the circuit current conduction.
[0034] The moving contact 2 includes a first moving contact piece 21 and a second moving contact piece 22 superimposed on the first moving contact piece 21. The first moving contact piece 21 is U-shaped, and the second moving contact piece 22 is straight. The length of the second moving contact piece 22 is less than the length of the first moving contact piece 21. A step 11 is provided on the inner side of the lower end of the stationary contact 1. When the stationary contact 1 contacts the moving contact 2, it contacts the first moving contact piece 21 and the second moving contact piece 22 through the lower end of the stationary contact 1 and the step 11, respectively. By setting the moving contact as a double contact piece and providing a step on the stationary contact, a double contact structure can be formed. Compared with the bridge-type moving contact single contact structure currently used in the market, it is possible to directly increase the contact head position inside the DC contactor, thereby increasing the current carrying capacity of the moving contact and improving the temperature rise performance.
[0035] A first anti-adhesion sheet 3 is provided on the step 11, and a second anti-adhesion sheet 4 is provided on the second moving contact 22. Both the first anti-adhesion sheet 3 and the second anti-adhesion sheet 4 are made of a high-melting-point, ablation-resistant material, including one or more of tungsten, copper tungsten, and copper tungsten carbide. By providing anti-adhesion sheets on the moving contact at the upper end of the moving contact and on the step of the stationary contact, the first anti-adhesion sheet 3 and the second anti-adhesion sheet 4 first contact the conducting circuit before the stationary contact 1 contacts the moving contact 2. Relying on the high melting point and ablation-resistant characteristics of the anti-adhesion sheet, it can withstand the large current at the millisecond level at the moment of connection, and can withstand the instantaneous large current of several times or even tens of times the rated current. Since the anti-adhesion sheet has a high melting point and is not easy to weld, the instantaneous current cannot damage the anti-adhesion sheet, thus achieving the anti-capacitive effect. Subsequently, the moving contact and the stationary contact come into contact to undertake the subsequent energizing function. At this time, the circuit voltage difference is very small, and there is almost no inrush current when the moving contact and the stationary contact are connected, thus protecting the contact assembly. The contact assembly also includes a guide plate 8, with a shaft 5 passing through the guide plate 8 and a magnetic sheet 7 mounted on the lower end of the guide plate 8. A first contact spring 9 is provided between the first moving contact sheet 21 and the guide plate 8, and a second contact spring 10 is provided between the first moving contact sheet 21 and the second moving contact sheet 22; a reaction spring 12 is provided between the moving iron core 6 and the guide plate 8.
[0036] In practical use, the moving iron core 6 is movably placed within the space enclosed by the coil. When the control circuit applies current, a magnetic field is generated inside the coil, attracting the moving iron core 6 to move towards the guide magnet 7, which in turn drives the shaft 5 upward. The first moving contact 21 and the second moving contact 22 move upward simultaneously. However, due to the different heights of the first moving contact 21 and the second moving contact 22, the two anti-sticking plates located on the second moving contact 22 and the step 11 of the stationary contact 1 make contact first. At this time, the circuit is connected, and the power supply instantaneously charges the equivalent capacitance of the circuit. The charging current is very large, several times or even tens of times the rated voltage. However, due to the high melting point of the anti-sticking plates, they are not easily welded. The instantaneous current must not damage the anti-sticking sheet; then the second moving contact 22 contacts the lower end of the stationary contact 1. Since the two anti-sticking sheets are connected first to charge the capacitor, the circuit voltage difference is very small at this time. When the second moving contact 22 is connected to the lower end of the stationary contact 1, there is almost no inrush current, which protects the contact assembly; at this time, the moving contact 2 contacts and closes with the stationary contact 1, thereby controlling the conduction of the circuit; when the control circuit is de-energized, the magnetic field inside the coil disappears, the circuit is interrupted, the return spring 12 pulls the shaft 5 to reset, then the first contact spring 9 pulls the first moving contact 21 to reset, the second contact spring 10 pulls the second moving contact 22 to reset, and the moving contact 2 returns to its original position.
[0037] In summary, this invention, by modifying the contact structure of the stationary contact 1 and the moving contact 2 and designing an anti-sticking sheet, integrates the pre-charge circuit function used in existing technologies into a DC contactor, achieving the DC contactor's resistance to capacitive surges. Furthermore, the product's structural design is simple, occupying almost no internal space of the DC contactor, eliminating the need for electronic components to construct the pre-charge circuit structure, resulting in lower manufacturing costs. It can be used in industries such as industrial vehicle starting and low-speed vehicle starting where capacitive connection may occur, and can handle capacitive loads far exceeding the rated current at the moment of connection, demonstrating excellent market application prospects. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial utilization value.
[0038] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.
Claims
1. A DC contactor capacitive contact assembly, comprising a stationary contact (1), a moving contact (2) and a drive mechanism, wherein the moving contact (2) is driven by the drive mechanism to make active contact with the stationary contact (1) to control the conduction of the circuit current; Its features are: The moving contact (2) includes a first moving contact piece (21) and a second moving contact piece (22) superimposed on the first moving contact piece (21). A step (11) is provided on the inner side of the lower end of the stationary contact (1). When the stationary contact (1) contacts the moving contact (2), the lower end of the stationary contact (1) and the step (11) respectively contact the first moving contact piece (21) and the second moving contact piece (22). The step (11) is provided with a first anti-sticking sheet (3), and the second moving contact sheet (22) is provided with a second anti-sticking sheet (4). The first anti-sticking sheet (3) and the second anti-sticking sheet (4) contact the conducting circuit before the stationary contact (1) and the moving contact (2) come into contact, so as to bear the large current at the moment of connection.
2. The DC contactor anti-capacitive contact assembly according to claim 1, characterized in that: Both the first anti-adhesion sheet (3) and the second anti-adhesion sheet (4) are made of high-melting-point ablation-resistant materials.
3. The DC contactor anti-capacitive contact assembly according to claim 2, characterized in that: The high melting point ablation-resistant materials used to make the first anti-adhesion sheet (3) and the second anti-adhesion sheet (4) include one or more of tungsten, copper tungsten, and copper tungsten carbide.
4. The DC contactor anti-capacitive contact assembly according to claim 1, characterized in that: Both the stationary contact (1) and the moving contact (2) are made of copper.
5. The DC contactor anti-capacitive contact assembly according to claim 1, characterized in that: The drive mechanism includes: Shaft (5), the first movable contact piece (21) and the second movable contact piece (22) are mounted on the upper end of shaft (5); A movable iron core (6) is sleeved on the lower end of the shaft (5); A magnetic sheet (7) is fitted above the moving iron core (6).
6. The DC contactor anti-capacitive contact assembly according to claim 5, characterized in that: The contact assembly also includes a guide plate (8), a shaft (5) passing through the guide plate (8), and a magnetic sheet (7) mounted on the lower end of the guide plate (8).
7. The DC contactor anti-capacitive contact assembly according to claim 6, characterized in that: A first contact spring (9) is provided between the first movable contact piece (21) and the guide plate (8), and a second contact spring (10) is provided between the first movable contact piece (21) and the second movable contact piece (22).
8. The DC contactor anti-capacitive contact assembly according to claim 6, characterized in that: A reaction spring (12) is provided between the moving iron core (6) and the guide plate (8).
9. The DC contactor anti-capacitive contact assembly according to claim 5, characterized in that: A retaining ring (13) is fitted at the lower end of the shaft (5), and the retaining ring (13) is positioned at the lower end of the moving iron core (6).