Capacitance-resistant contact assembly of direct current contactor

Abstract

The invention relates to the technical field of direct-current contactors, and particularly provides a direct-current contactor capacitance-resistant contact assembly which comprises a static contact, a moving contact and a driving mechanism. The moving contact comprises a first moving contact piece and a second moving contact piece, a step is arranged on the inner side of the lower end of the static contact, and the lower end of the static contact and the step are in contact with the first moving contact piece and the second moving contact piece respectively; the step is provided with a first anti-sticking sheet, the second movable contact sheet is provided with a second anti-sticking sheet, and the first anti-sticking sheet and the second anti-sticking sheet are in contact to conduct a loop before the static contact and the movable contact are in contact so as to bear large current at the moment of connection; by changing the contact structure of the static contact and the moving contact and designing the anti-sticking sheet, the pre-charging loop function adopted in the prior art can be combined in the direct current contactor, the capacitive impact resistance function of the direct current contactor is achieved, and the product is simple in structural design, low in manufacturing cost and good in market application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of direct current contactors, and in particular to an anti-capacitive contact assembly of a direct current contactor. Background Art

[0002] A DC contactor refers to a contactor used in a DC circuit, which is mainly used to control the conduction of the DC circuit (main circuit, control circuit, excitation circuit, etc.).

[0003] The contact structure used in the market is mostly a bridge-type dynamic single contact structure. In industries where capacitive connection exists, such as industrial vehicle starting, low-speed vehicle starting, etc., a large current far exceeding the rated current will appear at the moment the circuit is connected. The DC contactor cannot withstand the capacitive shock far exceeding the rated current at the moment of connection, and electric shock and adhesion are very likely to occur, affecting the normal use of the DC contactor.

[0004] To address the above issues, the current approach used in the market is to add a pre-charge circuit to limit the current at the moment of startup. Please refer to Figure 2 , Figure 2 The A area in the middle is the pre-charging circuit, which is composed of a pre-charging contactor and a current-limiting resistor. The pre-charging circuit and the main (-) circuit are opened first at the moment of connection, and the equivalent capacitor is charged from the pre-charging 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 setting of the pre-charging circuit occupies a large volume in the DC contactor, and the use effect is still not ideal. Summary of the invention

[0005] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a DC contactor anti-capacitive contact assembly for solving the problems of high cost and large volume occupied by limiting the current at the moment of starting by adding a pre-charge circuit in the prior art.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides a DC contactor anti-capacitive contact assembly, comprising a static contact, a moving contact and a driving mechanism, wherein the driving mechanism drives the moving contact to movably contact the static contact to control the conduction of the loop current;

[0007] The moving contact comprises a first moving contact piece and a second moving contact piece stacked on the first moving contact piece, and a step is arranged on the inner side of the lower end of the stationary contact. When the stationary contact contacts the moving contact, the lower end of the stationary contact and the step respectively contact the first moving contact piece and the second moving contact piece;

[0008] A first anti-sticking sheet is arranged on the step, and a second anti-sticking sheet is arranged on the second moving contact sheet. The first anti-sticking sheet and the second anti-sticking sheet first contact the conducting circuit before the static contact and the moving contact contact, so as to bear the large current at the moment of connection.

[0009] In one embodiment of the present invention, the first anti-adhesive sheet and the second anti-adhesive sheet are both made of a high melting point anti-ablation material.

[0010] In one embodiment of the present invention, the high melting point anti-ablation material used to make the first anti-adhesive sheet and the second anti-adhesive sheet includes one or more of tungsten, tungsten copper, and tungsten carbide copper.

[0011] In one embodiment of the present invention, the static contact and the moving contact are both made of copper.

[0012] In one embodiment of the present invention, the driving mechanism comprises:

[0013] A shaft, wherein the first moving contact piece and the second moving contact piece are mounted on the upper end of the shaft;

[0014] A moving iron core, wherein the moving iron core is sleeved on the lower end of the shaft;

[0015] The magnetic conductive sheet is matched above the moving iron core.

[0016] In one embodiment of the present invention, the contact assembly further includes a guide plate, the shaft is passed through the guide plate, and the magnetic conductive sheet is 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 the present invention, a reaction spring is provided between the moving iron core and the guide plate.

[0019] In one embodiment of the present invention, a retaining spring is sleeved on the lower end of the shaft, and the retaining spring is limited at the lower end of the moving iron core.

[0020] As described above, the DC contactor anti-capacitive contact assembly of the present invention has the following beneficial effects:

[0021] The present invention forms a double contact structure by arranging the moving contact as a double contact piece and arranging a step on the static contact. Compared with the bridge-type single contact structure currently used in the market, the contact head position can be directly increased inside the DC contactor, thereby achieving the purpose of increasing the current carrying capacity of the moving contact and improving the temperature rise performance; by arranging an anti-sticking sheet on the moving contact piece at the upper end of the moving contact and on the step of the static contact, before the moving contact contacts the static contact, the two anti-sticking sheets contact each other, and rely on the high melting point and anti-ablation characteristics of the anti-sticking sheet to withstand instantaneous ms-level large currents, and can withstand instantaneous large currents of several times or even dozens of times the rated current. Since the anti-sticking sheet has a high melting point and is not easy to weld, the instantaneous current cannot damage the anti-sticking sheet, thereby achieving an anti-capacitive effect; then the moving contact contacts the static contact to bear the subsequent power-on effect. At this time, the circuit pressure difference is very small, and there is almost no impact current when the moving contact and the static contact are connected, thereby protecting the contact assembly.

[0022] The present invention changes the contact structure of the static contact and the moving contact and designs an anti-sticking sheet, so that the pre-charging circuit function used in the prior art can be incorporated into the DC contactor to achieve the function of the DC contactor to resist capacitive impact. The product structure is simple in design and almost occupies no internal space of the DC contactor. There is no need to use electronic components to form a pre-charging circuit structure, and the production cost is low. It can be used in industries such as industrial vehicle starting and low-speed vehicle starting where capacitive connection may exist, and is used to bear capacitive loads that far exceed the rated current at the moment of connection. It has good market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic structural diagram of the present invention.

[0024] Figure 2 A schematic diagram showing the addition of a pre-filling circuit to the prior art.

[0025] Figure 3 It is a schematic diagram of the cross-sectional structure of the present invention without the static contact.

[0026] Figure 4 Shown is a schematic diagram of the three-dimensional structure of the present invention without the static contact.

[0027] Figure 5 Shown is an enlarged structural schematic diagram of the static contact in the present invention.

[0028] Figure 6 Display as Figure 5 Schematic diagram of the structure from another perspective.

[0029] Component number description

[0030] Static contact 1; step 11; moving contact 2; first moving contact piece 21; second moving contact piece 22; first anti-sticking piece 3; second anti-sticking piece 4; shaft 5; moving iron core 6; magnetic conductive piece 7; guide plate 8; first contact spring 9; second contact spring 10; reaction spring 12; retaining spring 13. DETAILED DESCRIPTION

[0031] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0032] See also Figures 1 to 6 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0033] See also Figure 1 , Figure 3-Figure 6 The present invention provides a DC contactor anti-capacitive contact assembly, including a static contact 1, a moving contact 2 and a driving mechanism. The static contact 1 and the moving contact 2 are both made of copper. The static contact 1 and the moving contact 2 made of copper can still ensure low internal resistance when the product is connected, so that the contactor can maintain a low temperature rise when powered on for a long time. The driving mechanism includes a shaft 5, a moving iron core 6, and a magnetic conductive sheet 7. The moving contact 2 is installed on the upper end of the shaft 5. The moving iron core 6 is sleeved on the lower end of the shaft 5. A retaining spring 13 is sleeved on the lower end of the shaft 5. The retaining spring 13 is limited at the lower end of the moving iron core 6 to improve the reliability of the connection between the shaft 5 and the moving iron core 6; the magnetic conductive sheet 7 is matched above the moving iron core 6; the driving mechanism drives the moving contact 2 to move and contact the static contact 1 to control the conduction of the loop current.

[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 set in a U shape, and the second moving contact piece 22 is set in a straight line shape. 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 set 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 contact the first moving contact piece 21 and the second moving contact piece 22 respectively. By setting the moving contact as a double contact piece and setting a step on the stationary contact, a double contact structure can be formed. Compared with the bridge-type single contact structure currently used in the market, the contact head position can be directly increased inside the DC contactor, so as to achieve the purpose of increasing the current carrying capacity of the moving contact and improving the temperature rise performance.

[0035] A first anti-sticking sheet 3 is arranged on the step 11, and a second anti-sticking sheet 4 is arranged on the second moving contact sheet 22. The first anti-sticking sheet 3 and the second anti-sticking sheet 4 are both made of a high melting point anti-ablation material, which includes one or more of tungsten, tungsten copper, and tungsten carbide copper. By arranging anti-sticking sheets on the moving contact sheet at the upper end of the moving contact and on the step of the static contact, the first anti-sticking sheet 3 and the second anti-sticking sheet 4 first contact the conduction circuit before the static contact 1 contacts the moving contact 2. Relying on the high melting point and anti-ablation characteristics of the anti-sticking sheet, it can withstand the instantaneous ms-level large current when connected, and can withstand an instantaneous large current of several times or even dozens of times the rated current. Due to the high melting point of the anti-sticking sheet, it is not easy to weld, so the instantaneous current cannot damage the anti-sticking sheet, thereby achieving an anti-capacitive effect. Subsequently, the moving contact contacts the static contact to bear the subsequent power-on effect. At this time, the circuit pressure difference is very small, and there is almost no impact current when the moving contact and the static contact are connected, thereby protecting the contact assembly. The contact assembly further includes a guide plate 8, the shaft 5 is passed through the guide plate 8, and the magnetic conductive sheet 7 is installed at the lower end of the guide plate 8. A first contact spring 9 is provided between the first moving contact piece 21 and the guide plate 8, a second contact spring 10 is provided between the first moving contact piece 21 and the second moving contact piece 22; and a reaction spring 12 is provided between the moving iron core 6 and the guide plate 8.

[0036] In specific use, the moving iron core 6 is movably placed in the space surrounded 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 toward the magnetic guide sheet 7, driving the shaft 5 to move upward, and the first moving contact sheet 21 and the second moving contact sheet 22 move upward at the same time. However, since the first moving contact sheet 21 and the second moving contact sheet 22 are arranged at different heights, the two anti-sticking sheets arranged on the second moving contact sheet 22 and on the step 11 of the static contact 1 first contact, and the circuit is turned on at this time, and the power supply instantly charges the equivalent capacitance of the circuit, and the charging current is very large, several times or even dozens of times the rated voltage, but due to the high melting point of the anti-sticking sheet, it is not easy to weld, so This instantaneous current cannot damage the anti-sticking sheet; then the second moving contact piece 22 contacts the lower end of the static contact 1. Since the two anti-sticking sheets are connected first to charge the capacitor, the circuit pressure difference is very small at this time. There is almost no impact current when the second moving contact piece 22 is connected to the lower end of the static contact 1, thereby protecting the contact assembly; at this time, the moving contact 2 is closed in contact with the static contact 1, thereby controlling the conduction of the circuit; when the control circuit is powered off, the magnetic field inside the coil disappears, the circuit is interrupted, and the reaction force spring 12 pulls the shaft 5 to reset, and then the first contact spring 9 pulls the first moving contact piece 21 to reset, the second contact spring 10 pulls the second moving contact piece 22 to reset, and the moving contact 2 returns to its original position.

[0037] In summary, the present invention changes the contact structure of the static contact 1 and the moving contact 2 and designs an anti-sticking sheet, so that the pre-charging circuit function used in the prior art can be incorporated into the DC contactor to realize the function of the DC contactor to resist capacitive impact. In addition, the product structure is simple in design, and almost does not occupy the internal space of the DC contactor. There is no need to use electronic components to form a pre-charging circuit structure, and the manufacturing cost is low. It can be used in industries such as industrial vehicle starting and low-speed vehicle starting where capacitive connection may exist, and is used to bear capacitive loads that far exceed the rated current at the moment of connection, and has good market application prospects. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A DC contactor anti-capacitive contact assembly, comprising a stationary contact (1), a moving contact (2) and a driving mechanism, wherein the moving contact (2) is driven by the driving mechanism to movably contact the stationary contact (1) to control the conduction of a loop current; Features: The moving contact (2) comprises 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); A first anti-sticking sheet (3) is provided on the step (11), and a second anti-sticking sheet (4) is provided on the second moving contact sheet (22). The first anti-sticking sheet (3) and the second anti-sticking sheet (4) first contact the conducting circuit before the static contact (1) and the moving contact (2) 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: The first anti-adhesive sheet (3) and the second anti-adhesive sheet (4) are both made of a high melting point ablation resistant material.

3. The DC contactor anti-capacitive contact assembly according to claim 2, characterized in that: The high melting point anti-ablation material used to make the first anti-adhesive sheet (3) and the second anti-adhesive sheet (4) includes one or more of tungsten, tungsten copper, and tungsten carbide copper.

4. The DC contactor anti-capacitive contact assembly according to claim 1, characterized in that: The static contact (1) and the moving contact (2) are both made of copper.

5. The DC contactor anti-capacitive contact assembly according to claim 1, characterized in that: The driving mechanism comprises: A shaft (5), wherein the first movable contact piece (21) and the second movable contact piece (22) are mounted on the upper end of the shaft (5); A moving iron core (6), wherein the moving iron core (6) is sleeved on the lower end of the shaft (5); A magnetic conductive sheet (7), wherein the magnetic conductive 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), the shaft (5) is passed through the guide plate (8), and the magnetic conductive sheet (7) is 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 moving contact piece (21) and the guide plate (8), and a second contact spring (10) is provided between the first moving contact piece (21) and the second moving contact piece (22).

8. The DC contactor anti-capacitive contact assembly according to claim 6, characterized in that: A reaction force 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: The lower end of the shaft (5) is sleeved with a retaining spring (13), and the retaining spring (13) is limited at the lower end of the moving iron core (6).

Images