Double-pole DC-DC contactor

Abstract

A double-gang DC contactor includes a housing and an upper base. The housing contains a magnetic guide frame, a magnetic plate, a moving armature, and a coil. The upper base contains a push rod. The surface of the magnetic plate facing the moving armature has evenly distributed circumferential protrusions, creating a gap between the end face of the moving armature and the area of ​​the magnetic plate without protrusions after the moving armature is attracted. An adhesive injection groove filled with sealant is located at the upper end of the housing. A cover strip is correspondingly located at the lower end of the upper base, inserted into and pressing against the sealant in the injection groove. This invention effectively improves the contactor's release voltage and the stability of the housing seal, enhancing the product's electrical reliability and environmental adaptability.

Description

Technical Field

[0001] This utility model relates to an electrical switching device, and more particularly to a double-gang DC contactor. Background Technology

[0002] In the field of DC contactors, the operational reliability of the electromagnetic system is one of the key performance indicators. In existing technologies, such as the commutator disclosed in Chinese invention patent CN101976635A, the electromagnetic components include an iron core, a coil, a lower magnetic plate, and an upper magnetic plate. The upper and lower magnetic plates form an encircling magnetic circuit through a magnetic outer ring, which drives the iron core and the movable contact bridge to achieve contact switching. However, the above-mentioned existing technologies have the following two shortcomings in practical applications:

[0003] 1. The magnetic plate and the iron core (or moving armature) of the existing contactor have a complete planar structure. When the iron core is attracted to the magnetic plate after the coil is energized, the two end faces are in a completely close state. After the magnetic circuit is closed, the air gap is almost zero, which causes the electromagnetic attraction to remain at a high level even when the voltage drops. This characteristic means that the iron core can only be pushed open and reset by the return spring when the voltage drops to below the minimum voltage value required for release. This results in a low release voltage. In applications with voltage fluctuations or requiring rapid disconnection, an excessively low release voltage may cause the contact to disconnect slowly, affecting the reliability and safety of circuit switching.

[0004] 2. Contactors typically operate in various environments, and the seal between the housing and the upper base directly affects the reliability of the internal contact system. Traditional assembly methods usually involve first fastening the housing to the upper base and then applying adhesive to seal the external joint; or placing a sealing ring between the housing and the upper base before fastening the upper base to the housing. The first method, external adhesive sealing, suffers from insufficient adhesive penetration and incomplete coverage. The sealing surface is prone to defects such as localized missing adhesive and porosity due to differences in assembly gaps or insufficient adhesive flow. The second method suffers from the sealing ring not completely filling the sealing area due to unstable pressure, resulting in localized missing adhesive in the sealing area. Both methods easily lead to poor sealing quality consistency. Poor sealing may cause internal contact oxidation, foreign object intrusion, and other malfunctions, ultimately affecting product lifespan and electrical safety. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies and provide a dual-phase DC contactor with improved electromagnetic release characteristics and a reliable sealing structure.

[0006] The technical solution adopted by this utility model to solve its technical problem is as follows: a double-gang DC contactor includes a housing and an upper seat covering the upper side of the housing. A magnetic guide frame is provided inside the housing, and a magnetic guide plate is mounted on the upper side of the magnetic guide frame. A moving armature and a coil for driving the moving armature are provided between the magnetic guide frame and the magnetic guide plate. A push rod is slidably provided inside the upper seat. One end of the push rod passes through the magnetic guide plate and abuts against the moving armature. On the side surface of the magnetic guide plate facing the moving armature, a plurality of protrusions are evenly provided along the circumference of the moving armature. When the moving armature is in the attracted state, a gap is formed between the end face of the moving armature facing the magnetic guide plate and the area of ​​the magnetic guide plate where the protrusions are not provided. The upper end port of the housing is provided with a glue injection groove along its circumference. The glue injection groove is filled with sealant. The lower end port of the upper seat is provided with a cover strip inserted into the glue injection groove. The cover strip presses against the sealant.

[0007] Preferably, the height of the end face of the boss relative to the surface of the magnetic plate facing the moving armature is 0.05 mm to 0.2 mm.

[0008] Preferably, a return spring is also sleeved between the push rod and the upper seat, and the return spring applies a force to the push rod to move it away from the moving armature.

[0009] The beneficial effects of this utility model are:

[0010] 1. By setting micron-sized protrusions on the magnetic plate's contact surface, the end face of the moving armature cannot completely fit with the magnetic plate body after it is attracted into place. Instead, a tiny, fixed air gap is forcibly formed. The existence of this air gap effectively reduces the residual magnetic holding force between the magnetic plate and the moving armature after the coil is de-energized. This allows the return spring to push open the moving armature at a relatively high voltage, significantly improving the contactor's release voltage and ensuring the speed and reliability of contact disconnection.

[0011] 2. By pre-filling the glue injection groove at the upper end of the housing with glue, and then pressing it with the upper cover strip, the fluidity of the sealant is utilized to evenly fill the space between the cover strip and the groove wall during the pressing process, forming a complete and continuous annular sealing surface. This combination of "pre-filling glue and then assembling" structure and process completely avoids sealing defects such as insufficient glue or air holes caused by traditional external glue application methods, and greatly improves the stability and consistency of the contactor housing sealing quality. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the overall structure of an embodiment of this utility model;

[0013] Figure 2 This is a utility model Figure 1 Enlarged view of point A.

[0014] In the diagram: 1. Outer shell; 11. Injection groove; 12. Sealant; 2. Upper seat; 21. Cover strip; 22. Upper contact bridge; 23. Lower contact bridge; 24. Stud; 25. Nut; 3. Magnetic guide bracket; 4. Magnetic guide plate; 41. Boss; 5. Moving armature; 6. Coil; 7. Push rod; 71. Return spring; 72. Movable contact bridge. Detailed Implementation

[0015] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. Example

[0016] like Figures 1 to 2 The illustrated double-pole DC contactor includes a housing 1 and an upper seat 2 covering the upper side of the housing 1. The interior space of the housing 1 mainly houses the electromagnetic system, while the upper seat 2 mainly houses the contact system.

[0017] A magnetically conductive mounting bracket 3 is fixedly installed on the bottom side inside the outer casing 1. A flat magnetically conductive plate 4 is mounted above the magnetically conductive mounting bracket 3. Within the space enclosed by the magnetically conductive mounting bracket 3 and the magnetically conductive plate 4, a movable armature 5 that can move up and down is installed, along with a coil 6 surrounding it. When the coil 6 is energized, it generates a magnetic field. Through the combined magnetic guidance of the magnetically conductive mounting bracket 3 and the magnetically conductive plate 4, a closed magnetic circuit is formed, driving the movable armature 5 to overcome the elastic force of the return spring 71 and be attracted to the magnetically conductive plate 4.

[0018] One of the key improvements in this embodiment is that the lower surface of the magnetic plate 4 facing the moving armature 5 is not a complete plane, but rather has four small, uniformly shaped protrusions 41 with rectangular cross-sections uniformly integrally formed along the annular area of ​​its surface that mates with the moving armature 5. In this embodiment, the height of the end face of the protrusion 41 relative to the lower surface of the magnetic plate 4 body is 0.10 mm. Accordingly, when the coil 6 is energized and attracts the moving armature 5 into place, the upper end face of the moving armature 5 does not adhere to the entire surface of the magnetic plate 4, but only contacts the end faces of these four protrusions 41. Therefore, a precisely controlled, uniform 0.10 mm annular gap (air gap) is formed between the upper end face of the moving armature 5 and all other areas on the magnetic plate 4 where no protrusions 41 are provided. It is this forced retention of a small gap that reduces the residual attraction force in the magnetic circuit, allowing the moving armature 5 to be pushed open by the return spring 71 at a higher voltage threshold when the coil 6 is de-energized and the voltage drops, thereby increasing the product's release voltage. It should be noted that the height H of the boss 41 can be selected and manufactured within the range of 0.05mm to 0.2mm according to the specific required release voltage value, so as to accurately match the design parameters of different contactor models.

[0019] On one side of the upper seat 2, a push rod 7 is slidably disposed inside. The lower end of the push rod 7 passes through the central hole on the magnetic guide plate 4 and abuts against the center of the upper end face of the moving armature 5. A return spring 71 is sleeved on the push rod 7. One end of the return spring 71 abuts against the upper seat 2, and the other end acts on the step of the push rod 7, continuously applying a force to the push rod 7 to move it away from the moving armature 5. This force is the power to drive the push rod 7 and the movable contact bridge 72 to reset. The movable contact bridge 72 is fixedly installed on the push rod 7. Corresponding to the left end of the movable contact bridge 72, the upper seat 2 is provided with an upper contact bridge 22 and a lower contact bridge 23; corresponding to the right end of the movable contact bridge 72, the upper seat 2 is provided with a curved contact bridge (not shown in the figure). The right end of the movable contact bridge 72 slides in contact within the arc-shaped track of the curved contact bridge (not shown in the figure). Both the upper contact bridge 22 and the curved contact bridge (not shown in the figure) are fixed with studs 24 for external wiring, and nuts 25 for clamping external wire terminals are screwed onto the studs 24. By engaging and disengaging the moving armature 5, the push rod 7 and the movable contact bridge 72 move up and down, realizing the switching of the double-connector state of the movable contact bridge 72 between the upper contact bridge 22 and the lower contact bridge 23 and within the curved contact bridge (not shown in the figure).

[0020] Another key improvement in this embodiment lies in the sealing structure between the outer shell 1 and the upper seat 2. The outer shell 1 has an annular injection groove 11 along its upper port edge. During assembly, before fastening the upper seat 2 to the outer shell 1, a certain amount of liquid sealant 12 is evenly injected and distributed throughout the injection groove 11 using a dispensing device. Then, the upper seat 2 is pressed down to fasten. At this time, a continuous cover strip 21 protruding downwards from the periphery of the lower port of the upper seat 2 is precisely inserted into and pressed against the sealant 12 within the injection groove 11. Because the sealant 12 still has good fluidity before pressing, it can fully fill all the gaps between the cover strip 21 and the side and bottom walls of the injection groove 11 after being pressed, forming an annular sealing barrier with no internal pores and a continuous and stable structure. This sealing structure, composed of the injection groove 11, the cover strip 21, and the sealant 12, ensures the integrity and consistency of the product's sealing surface quality from the source, effectively overcoming the drawbacks of traditional external gluing and the use of sealing rings.

Claims

1. A double-gang DC contactor, comprising a housing (1) and an upper seat (2) covering the upper side of the housing (1), wherein a magnetic guide frame (3) is provided inside the housing (1), a magnetic guide plate (4) is mounted on the upper side of the magnetic guide frame (3), a moving armature (5) and a coil (6) for driving the moving armature (5) are provided between the magnetic guide frame (3) and the magnetic guide plate (4), and a push rod (7) is slidably provided inside the upper seat (2), one end of the push rod (7) passing through the magnetic guide plate (4) and abutting against the moving armature (5), characterized in that: The magnetic plate (4) has a plurality of protrusions (41) evenly provided on one side surface facing the moving armature (5) along the circumference of the moving armature (5). The protrusions (41) create a gap between the end face of the moving armature (5) facing the magnetic plate (4) and the area on the magnetic plate (4) where the protrusions (41) are not provided when the moving armature (5) is in the attracted state. The upper end port of the outer shell (1) is provided with a glue injection groove (11) along its circumference. The glue injection groove (11) is filled with sealant (12). The lower end port of the upper seat (2) is provided with a cover strip (21) inserted into the glue injection groove (11). The cover strip (21) presses against the sealant (12).

2. The dual conversion DC contactor of claim 1, wherein: The height of the end face of the boss (41) relative to the surface of the magnetic plate (4) facing the moving armature (5) is 0.05 mm to 0.2 mm.

3. The dual conversion DC contactor of claim 1, wherein: The push rod (7) and the upper seat (2) are further sleeved with a return spring (71), and the return spring (71) applies promote the force of the moving armature (5).

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