A DC contactor based on short circuit resistance

Abstract

The invention discloses a DC contactor based on short circuit resistance, wherein two static contacts are arranged on an upper support plate, a lower magnetic yoke is arranged between the upper support plate and the lower support plate, the upper part of the lower magnetic yoke is connected to the upper support plate through an upper armature, a flat moving contact is arranged in the lower magnetic yoke, the two ends of the flat moving contact extend to the outside of the lower magnetic yoke and are respectively connected to the corresponding static contacts, a final pressure spring is arranged between the lower side of the flat moving contact and the lower magnetic yoke, a moving iron core is arranged on the lower side of the lower support plate, and the moving iron core and the lower magnetic yoke are connected through a lower magnetic yoke connecting rod; a group of magnetic steel sheets are respectively arranged on both sides of the connection between the flat moving contact and the corresponding static contact. The invention provides suction force for the lower magnetic yoke through the electromagnetic suction force generated by the magnetic circuit designed based on the electromagnetic principle, which is used to offset the Holm repulsion force generated by the moving and static contacts, and the direct-acting release method is simple, and the short circuit resistance capacity can be adjusted.

Description

Technical Field

[0001] The invention belongs to the technical field of switch electrical appliances, and in particular relates to a short-circuit-resistant DC contactor. Background Art

[0002] At present, DC contactors are the most widely used switching electrical products in new energy fields such as new energy vehicles, photovoltaics, and energy storage. However, their maximum breaking capacity, that is, the maximum short-circuit resistance, has always been a difficult parameter indicator. When there is a large short-circuit current (for example, more than 20 times the rated current), the electromagnetic repulsion generated between the moving and static contacts of the contactor will cause the contacts to open. Under this condition, a strong arc will be generated, which will burn out the moving and static contacts of the contactor and cause the contactor to fail. The key point to improve the short-circuit resistance is that when a large current is generated (tens of times the rated current), the pressure between the moving and static contacts is still greater than the electromagnetic repulsion, so that it can be closed reliably; currently, there are generally two ways to increase the closing force between the moving and static contacts. One is to increase the electromagnetic attraction force through the electromagnetic coil, and the other is to reduce the electromagnetic repulsion. Due to the operational requirements of the product structure and electrical life, the electromagnetic force cannot be increased indefinitely. At present, there are also some schemes that install a short-circuit current-resistant magnetic ring composed of an upper yoke and a lower armature at the moving spring. When the short-circuit current flows through the moving spring, a circular magnetic field will be generated around the moving spring, which will cause the upper yoke and the lower armature to generate suction. The magnetic ring composed of the upper yoke and the lower armature will form a suction force in the direction of contact pressure on the moving spring, so that the moving and static contacts will not bounce open. With the increase of current, the electromagnetic field of this structure will gradually saturate, which can improve the short-circuit resistance to a certain extent, but the improvement is very limited after all.

[0003] The arc extinguishing of DC contactors usually adopts magnetic blowing, that is, placing magnets around the moving and static contacts. Although magnets are beneficial to the arc extinguishing of DC contactors and prolonging the electrical life, many schemes are difficult to effectively improve the arc extinguishing ability, especially in the aspect of non-polarity arc extinguishing. Many magnet design and placement schemes are not very effective. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a DC contactor based on short-circuit resistance in view of the deficiencies in the above-mentioned prior art. The anti-short-circuit electromagnetic mechanism can generate a large electromagnetic force to offset the electromagnetic repulsion between the moving and static contacts, thereby greatly improving the product's short-circuit resistance. The use of this solution makes the short-circuit resistance reach a maximum level of 20kA; by designing the structure and position of the arc-extinguishing magnetic steel, not only the arc-extinguishing ability of the product can be improved, but also the non-polarity arc-extinguishing ability of the DC contactor can be improved.

[0005] The present invention adopts the following technical solutions:

[0006] A short-circuit-resistant DC contactor comprises an upper support plate and a lower support plate, wherein two static contacts are arranged on the upper support plate, a lower magnetic yoke is arranged between the upper support plate and the lower support plate, the upper part of the lower magnetic yoke is connected to the upper support plate through an upper armature, a flat moving contact is arranged inside the lower magnetic yoke, two ends of the flat moving contact extend to the outside of the lower magnetic yoke and are respectively connected to the corresponding static contacts, a final pressure spring is arranged between the lower side of the flat moving contact and the lower magnetic yoke, a moving iron core is arranged on the lower side of the lower support plate, and the moving iron core and the lower magnetic yoke are connected through a lower magnetic yoke connecting rod; a group of magnetic steel sheets are respectively arranged on both sides of the connection between the flat moving contact and the corresponding static contact.

[0007] Specifically, the upper support plate is connected to the upper side of the upper armature through the upper armature connecting rod, the lower side of the upper armature is movably connected to the top of the lower magnetic yoke, the center of the flat moving contact is connected to one end of the final pressure spring, the other end of the final pressure spring is connected to the bottom of the lower magnetic yoke, and the two ends of the flat moving contact are respectively connected to the lead-out ends of the static contact.

[0008] Furthermore, the upper armature is a trapezoidal structure, a notch is formed at the upper portion of the lower magnetic yoke corresponding to the trapezoidal structure, and the upper armature is arranged in the notch to realize magnetic conduction.

[0009] Furthermore, one end of the lower yoke connecting rod is connected to the lower part of the lower yoke, and the other end passes through the lower supporting plate and is arranged in the moving iron core.

[0010] Specifically, the upper armature is connected to the upper support plate through the upper armature connecting rod, the lower magnetic yoke includes an upper cavity and a lower cavity, the flat moving contact is arranged in the upper cavity, and the two ends of the flat moving contact are respectively in contact with the lead-out ends of the static contact when closed, and the final pressure spring is arranged in the lower cavity, and the bottom of the final pressure spring is connected to one end of the lower magnetic yoke connecting rod.

[0011] Furthermore, the upper portion of the lower magnetic yoke is an inclined structure, and the upper armature is obliquely arranged above the inclined structure of the lower magnetic yoke.

[0012] Furthermore, the upper armature and the upper armature connecting rod are fixedly connected or movably connected via a rotating shaft, and a reset device is provided at the connection between the rotating shaft and the upper armature.

[0013] Furthermore, the reset device comprises a torsion spring or a reset spring leaf, the torsion spring is arranged at the rotating shaft, and the reset spring leaf is arranged at the center of the upper armature.

[0014] Furthermore, a lower yoke connecting block is arranged on the lower support plate, the lower yoke is arranged on the lower yoke connecting block, and the other end of the lower yoke connecting rod passes through the lower yoke connecting block and the lower support plate and is arranged in the moving iron core.

[0015] Specifically, a U-shaped yoke is correspondingly arranged on the outside of each group of magnetic steel sheets, the magnetic steel sheets are adsorbed and connected to the U-shaped yoke, and the inner side of each group of magnetic steel sheets is placed according to NN or SS.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects:

[0017] The invention discloses a short-circuit-resistant DC contactor, which adopts common parts such as an upper armature, a lower magnetic yoke and a flat movable contact, and has low cost. When a large current passes through a conductive circuit, the flat movable contact forms a magnetic circuit with the upper armature and the lower magnetic yoke, and the upper armature is subjected to the electromagnetic attraction of the lower magnetic yoke. Without changing the upper armature or the lower magnetic yoke, as the current increases, the electromagnetic attraction of the upper armature to the lower magnetic yoke increases, and the electromagnetic repulsion between the movable and static contacts can be offset, thereby improving the short-circuit resistance. A new type of magnetic steel sheet placement method is adopted, in which NN and SS polar magnetic steel sheets are placed outside the movable and static contacts, so as to improve the arc extinguishing capability, and can also improve the non-polarity capability of the DC contactor, thereby improving the core competitiveness of the product.

[0018] Furthermore, the upper armature is arranged on the upper part of the lower magnetic yoke and is movably connected to the lower magnetic yoke. Its purpose is that when a larger short-circuit current (for example, several kA) passes through, a larger Holm repulsion force is generated at the contact surface between the flat moving contact and the static contact, which will cause them to separate, and the current of the flat moving contact will form a magnetic circuit between the upper armature and the lower magnetic yoke, and there is a V-shaped interface between the upper armature and the lower magnetic yoke. Due to the closed characteristics of the magnetic circuit, the upper armature and the lower magnetic yoke will be forced to fit together. Since the upper armature is fixed, the lower magnetic yoke connected to the flat moving contact is subjected to the electromagnetic attraction of the upper armature, so that the moving and static contacts can remain without being repelled, thereby improving the short-circuit resistance.

[0019] Furthermore, the upper armature is a trapezoidal structure, and a notch is opened in the upper part of the lower magnetic yoke corresponding to the trapezoidal structure. When a large short-circuit current passes through, the trapezoidal upper armature and the lower magnetic yoke form a magnetic circuit, and its oblique structure will generate electromagnetic attraction, which will generate an upward attraction on the lower magnetic yoke to offset the Holm repulsion between the moving and static contacts, thereby improving the short-circuit resistance.

[0020] Furthermore, one end of the lower yoke connecting rod is connected to the lower part of the lower yoke, and the other end passes through the lower support plate and is arranged in the moving iron core. The purpose or benefit of the arrangement is that the electromagnetic attraction of the coil on the moving iron core can directly act on the lower yoke, and the yoke is more efficiently subjected to force.

[0021] Furthermore, the upper armature is connected to the upper support plate through an upper armature connecting rod, the lower magnetic yoke includes an upper cavity and a lower cavity, the flat moving contact is arranged in the upper cavity, and the two ends of the flat moving contact are respectively in contact with the lead-out ends of the static contact when closed, and the final pressure spring is arranged in the lower cavity, and the bottom of the final pressure spring is connected to one end of the lower magnetic yoke connecting rod. The upper armature is more firmly connected to the structurally fixed upper support plate, and the flat moving contact is constrained in the lower magnetic yoke through a spring. When the moving and static contacts are in contact, the spring can provide final pressure to the contact for closing and reducing the Holm force. At the same time, the lower magnetic yoke has a limiting and constraining effect on the flat moving contact.

[0022] Furthermore, the upper portion of the lower magnetic yoke is an inclined structure, the purpose of which is to generate electromagnetic attraction in the magnetic circuit, causing the magnetic yoke to be attracted by the upper armature.

[0023] Furthermore, the upper armature is fixedly connected or rotationally connected to the upper support member through a structural member, wherein the rotational connection of the snap-fit ​​structure requires the installation of a reset device to provide a reset force or a reaction force for the upper armature.

[0024] Furthermore, the purpose of adjusting the elastic coefficient of the torsion spring or the size of the spring leaf is to make the suction force between the upper armature and the lower magnetic yoke adjustable, thereby providing different short-circuit resistance capabilities.

[0025] Furthermore, the lower yoke is arranged on the lower yoke connecting block, and the other end of the lower yoke connecting rod passes through the lower yoke connecting block and the lower support plate and is arranged in the moving iron core for the purpose of installation and fixing manufacturing process requirements.

[0026] Furthermore, the U-shaped magnetic yoke is easy to be installed or fixed outside the ceramic cavity, and the U-shaped magnetic yoke can connect the magnetic fields of the two permanent magnets to enhance each other.

[0027] In summary, the present invention provides suction for the lower magnetic yoke through the electromagnetic suction force generated by the magnetic circuit designed based on the electromagnetic principle, which is used to offset the Holm repulsion generated by the moving and static contacts. The direct-acting release method is simple, and the electromagnetic suction between the upper armature and the magnetic yoke can be adjusted by adjusting the size and the bevel angle of the upper armature. The snap-on upper armature can adjust the electromagnetic suction with the lower magnetic yoke by adjusting the bevel angle and the reaction force torsion spring (spring leaf), and both can achieve adjustable short-circuit resistance. At the same time, the manufacturing and process methods are feasible, which is a highly innovative solution.

[0028] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a three-dimensional schematic diagram of the partial structure of Example 1 of the present invention;

[0030] Figure 2 It is a front view of the partial structure of Example 1 of the present invention;

[0031] Figure 3 for Figure 2 Section view along plane AA;

[0032] Figure 4 This is a schematic diagram of the coordination of the upper armature, the lower magnetic yoke, the flat moving contact, etc. of Example 1 of the present invention;

[0033] Figure 5 The figure is a schematic diagram of the magnetic flux distribution when the upper armature, the lower magnetic yoke and the flat moving contact of the embodiment 1 of the present invention are energized;

[0034] Figure 6 It is a three-dimensional schematic diagram of the partial structure of Example 2 of the present invention;

[0035] Figure 7 It is a front view of a partial structure of Example 2 of the present invention;

[0036] Figure 8 for Figure 7 Section view along plane AA;

[0037] Fig. 9 This is a schematic diagram of the coordination of the upper armature, the lower magnetic yoke, the flat moving contact, etc. of Example 2 of the present invention;

[0038] Fig.10 It is a schematic diagram of magnetic flux distribution when the upper armature, the lower magnetic yoke and the flat moving contact of Example 2 of the present invention are energized;

[0039] Fig.11 Schematic diagram of the cooperation between the magnetic steel and the U-shaped yoke iron of Embodiment 1 and Embodiment 2 of the present invention;

[0040] Fig.12 A schematic diagram of the position arrangement and magnetic field distribution of a magnetic steel according to Embodiment 1 and Embodiment 2 of the present invention;

[0041] Fig.13 Schematic diagram of another magnetic steel position arrangement and magnetic field distribution according to Embodiment 1 and Embodiment 2 of the present invention.

[0042] Among them: 1. static contact; 2. upper support plate; 3. magnetic steel sheet; 4. flat moving contact; 51. upper armature; 52. upper armature connecting rod; 61. lower yoke; 62. lower yoke connecting block; 63. lower yoke connecting rod; 7. final pressure spring; 8. lower support plate; 9. moving iron core; 10. U-shaped yoke. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0047] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0048] The present invention provides a short-circuit-resistant DC contactor, in which an upper armature is mounted on an upper support, and a lower yoke moves up and down with a moving contact, wherein the upper armature and the lower yoke are in full contact when the moving and static contacts are closed, and the two contact surfaces form a certain angle. When current passes through, the upper armature, the lower yoke and the flat moving contact will form a closed-loop electromagnetic system, and the greater the current passing through the flat moving contact, the greater the attraction between the armature and the yoke. The present invention can increase the electromagnetic force and eliminate part of the electromagnetic repulsion between the moving and static contacts, thereby greatly improving the product's short-circuit resistance, and the maximum short-circuit resistance current can reach 20kA level.

[0049] See also Figure 1 , Figure 2 and Figure 3 The present invention discloses a short-circuit-resistant DC contactor, comprising: two static contacts 1, an upper support plate 2, two groups of magnetic steel sheets 3, a flat moving contact 4, an upper armature 51, an upper armature connecting rod 52, a lower magnetic yoke 61, a lower magnetic yoke connecting rod 63, a final pressure spring 7, a lower support plate 8 and a moving iron core 9.

[0050] The two static contacts 1 are respectively arranged on the upper support plate 2, and the lead ends of the two static contacts 1 are respectively connected to the two ends of the flat moving contact 4. The lower side of the upper support plate 2 is connected to the upper armature 51 through the upper armature connecting rod 52. The upper armature 51 is arranged on the upper part of the lower magnetic yoke 61 and is movably connected to the lower magnetic yoke 61. The flat moving contact 4 passes through the lower magnetic yoke 61. A final pressure spring 7 is arranged in the lower magnetic yoke 61 below the flat moving contact 4. The two ends of the flat moving contact 4 extend to the outside of the lower magnetic yoke 61 and are respectively connected to the lead ends of the corresponding static contacts 1. A group of magnetic steel sheets 3 are respectively arranged on both sides of the outside of the two ends of the flat moving contact 4, and one end of each group of magnetic steel sheets 3 is connected to the upper support plate 2; the lower part of the lower magnetic yoke 61 is connected to one end of the lower magnetic yoke connecting rod 63, and the other end of the lower magnetic yoke connecting rod 63 passes through the lower support plate 8 and is arranged in the moving iron core 9.

[0051] See also Figure 4 The upper armature 51 of the DC contactor is fixedly connected to the upper support plate 2 through the upper armature connecting rod 52. A notch is opened on the upper part of the lower magnetic yoke 61. The upper armature 51 is a trapezoidal structure and can be arranged in the notch to contact the lower magnetic yoke 61. A flat moving contact 4 is arranged in the lower magnetic yoke 61. The upper armature 51 is arranged above the flat moving contact 4. The final pressure spring 7 is arranged below the flat moving contact 4. One end of the final pressure spring 7 is connected to the flat moving contact 4, and the other end is connected to the lower magnetic yoke 61.

[0052] See also Figure 5 The flat moving contact 4 moves with the lower yoke 61, the lower yoke connecting rod 63 and the final pressure spring 7; when the rated current is passed, the flat moving contact 4 forms a closed conductive magnetic ring with the upper armature 51 and the lower yoke 61. When the lead-out end of the static contact 1 and the flat moving contact 4 generate a fault short-circuit current of ≥5kA, the lead-out end of the static contact 1 and the contact position of the flat moving contact 4 generate an electromagnetic repulsion of ≥50N. Due to the structure of the magnetic closed loop and the contact surface between the upper armature 51 and the lower yoke 61, a large electromagnetic attraction is generated, which eliminates and offsets part of the electromagnetic repulsion between the moving and static contacts, ensuring that the moving and static contacts are closed without being bounced open by the electromagnetic repulsion. Therefore, the short-circuit resistance of the contactor is improved, and the maximum short-circuit resistance reaches 20kA.

[0053] See also Figure 6 and Figure 7, which is the second embodiment of the present invention - a snap-on structure. When a large current is generated, the current flowing through the flat moving contact 4 forms a magnetic circuit between the lower yoke 61 and the upper armature 51. The magnetic circuit generates an electromagnetic attraction at the oblique structure and increases with the increase of the current until the magnetic field intensity approaches saturation. The fixed upper armature 51 prompts the lower yoke 61 to generate an attraction, which can offset the Holm repulsion generated between the moving and static contacts, ensure the moving and static contacts are attracted, and improve the short-circuit resistance.

[0054] The two static contacts 1 are respectively arranged on the upper support plate 2, and the lead ends of the two static contacts 1 are respectively connected to the two ends of the flat moving contact 4. The lower side of the upper support plate 2 is connected to the upper armature 51 through the upper armature connecting rod 52. The upper armature 51 is arranged on the upper part of the lower magnetic yoke 61. The flat moving contact 4 penetrates the lower magnetic yoke 61. A final pressure spring 7 is arranged in the lower magnetic yoke 61 below the flat moving contact 4. The final pressure spring 7 is connected to the moving iron core 9 through the lower magnetic yoke connecting rod 63.

[0055] See also Figure 8 The lower magnetic yoke 61 includes an upper cavity and a lower cavity, the flat moving contact 4 is arranged in the upper cavity, the two ends of the flat moving contact 4 extend to the outside of the lower magnetic yoke 61 and are respectively connected to the lead-out ends of the corresponding static contact 1, and a group of magnetic steel sheets 3 are respectively arranged on the outer sides of the two ends of the flat moving contact 4, and one end of each group of magnetic steel sheets 3 is connected to the upper support plate 2; a lower magnetic yoke connecting block 62 is arranged on the lower support plate 8, and the final pressure spring 7 is arranged in the lower cavity, the lower cavity is connected to one side of the lower support plate 8 through the lower magnetic yoke connecting block 62, and the moving iron core 9 is arranged on the other side of the lower support plate 8. One end of the lower magnetic yoke connecting rod 63 is arranged in the moving iron core 9, and the other end is connected to the final pressure spring 7 after passing through the lower support plate 8 and the lower magnetic yoke connecting block 62 in sequence.

[0056] See also Fig. 9 The upper armature 51 and one end of the upper armature connecting rod 52 are fixedly connected, or movably connected through a rotating shaft, a torsion spring is installed at the rotating shaft or a reset spring is installed at the center of the upper armature 51 to provide a reset force for the upper armature, and the contact surface between the upper armature 51 and the lower magnetic yoke 61 is an inclined surface. 52 is fixed on the upper bracket for greater stability. If it is connected by a rotating shaft, the electromagnetic attraction between the upper armature and the lower magnetic yoke is adjustable, thereby adjusting the short-circuit resistance.

[0057] See also Fig.10 , magnetic flux distribution and Figure 5 When it is attracted, it is similar. There are two differences. One is that the two magnetic flux densities are different. Figure 5 Denser is more likely to cause magnetic saturation. Another is Fig.10 The structure with adjustable torsion spring is more prone to saturation on one side of the rotating axis.

[0058] The upper armature 51 of the DC contactor is fixedly connected to the upper support plate 2 through the upper armature connecting rod 52, and the flat moving contact 4 cooperates with the lower yoke 61, the lower yoke connecting rod 63 and the final pressure spring 7; when the rated current is passed, the flat moving contact 4 forms a closed conductive magnetic ring with the upper armature 51 and the lower yoke 61. When the static contact lead-out terminal 1 and the flat moving contact 4 generate a fault short-circuit current of ≥5kA, the lead-out terminal of the static contact 1 and the contact position of the flat moving contact 4 generate an electromagnetic repulsion of ≥50N, and the upper armature 51 and the lower yoke 61 will generate an electromagnetic attraction of ≥20N due to the structure of the magnetic closed loop and the contact surface thereof, thereby eliminating and offsetting a part of the electromagnetic repulsion between the moving and static contacts, ensuring that the moving and static contacts are closed without being bounced open by the electromagnetic repulsion, thereby improving the short-circuit resistance of the contactor, and the maximum short-circuit resistance reaches 20kA.

[0059] The upper armature 52 and the lower yoke 61 are made of ferromagnetic material, such as electrical pure iron DT4.

[0060] The length, width and height dimensions of the upper armature 52 and the lower yoke 61 and the angles of their mating surfaces are adjustable. For example, the inclined surface can be processed to have an angle of 5° to 30° (with the transverse plane of the lower yoke 61). The electromagnetic attraction between the upper armature 52 and the lower yoke 61 is different, and the Holm repulsion between the moving and static contacts changes accordingly. Therefore, the short-circuit resistance of the DC contactor is also adjustable.

[0061] See also Fig.11 The DC contactor also includes a U-shaped yoke 10, two groups of magnetic steel sheets 3 are respectively adsorbed on the corresponding U-shaped yoke 10, each group of magnetic steel sheets 3 is placed at the lead-out end of the static contact 1 and the outer side of the flat movable contact 4, and the U-shaped yoke 10 is made of ferromagnetic material.

[0062] See also Fig.12 and Fig.13 The magnetic steel sheets of the DC contactor are permanent magnetic materials, such as neodymium iron boron, etc. Each group of magnetic steel sheets is located on both sides of the static contact 1 and the flat moving contact 4. Each group of magnetic steel sheets 3 is placed according to the inner side NN or SS to achieve non-polarity arc extinguishing.

[0063] In summary, the present invention is a DC contactor based on short-circuit resistance. For scheme 1 to improve short-circuit resistance, a direct-acting upper armature structure (contact slope 45°, width is 1 / 2 of the lower yoke) is adopted, and a test comparison is carried out with a scheme without short-circuit resistance. The short-circuit resistance of scheme 1 reaches 15kA, while the short-circuit resistance of the scheme without short-circuit resistance is only 10kA, and the short-circuit resistance is improved by 50%.

[0064] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A DC contactor based on short circuit resistance, characterized in that: The invention comprises an upper support plate (2) and a lower support plate (8), wherein two static contacts (1) are arranged on the upper support plate (2), a lower magnetic yoke (61) is arranged between the upper support plate (2) and the lower support plate (8), the upper part of the lower magnetic yoke (61) is connected to the upper support plate (2) via an upper armature (51), a flat plate moving contact (4) is arranged inside the lower magnetic yoke (61), two ends of the flat plate moving contact (4) extend to the outside of the lower magnetic yoke (61) and are respectively connected to the corresponding static contacts (1), a final pressure spring (7) is arranged between the lower side of the flat plate moving contact (4) and the lower magnetic yoke (61), a moving iron core (9) is arranged on the lower side of the lower support plate (8), and the moving iron core (9) and the lower magnetic yoke (61) are connected via a lower magnetic yoke connecting rod (63); a group of magnetic steel sheets (3) are respectively arranged on both sides of the connection between the flat plate moving contact (4) and the corresponding static contact (1); The upper armature (51) is connected to the upper support plate (2) via an upper armature connecting rod (52); the lower magnetic yoke (61) comprises an upper cavity and a lower cavity; the flat plate moving contact (4) is arranged in the upper cavity; the two ends of the flat plate moving contact (4) are respectively in contact with the lead-out ends of the static contact (1) when closed; the final pressure spring (7) is arranged in the lower cavity; the bottom of the final pressure spring (7) is connected to one end of the lower magnetic yoke connecting rod (63); the upper part of the lower magnetic yoke (61) is an inclined structure; the upper armature (51) is obliquely arranged above the inclined structure of the lower magnetic yoke (61); the upper armature (51) and the upper armature connecting rod (52) are fixedly connected or movably connected via a rotating shaft; and a reset device is provided at the connection between the rotating shaft and the upper armature (51).

2. The short-circuit-resistant DC contactor according to claim 1, characterized in that: The upper support plate (2) is connected to the upper side of the upper armature (51) via an upper armature connecting rod (52); the lower side of the upper armature (51) is movably connected to the top of the lower magnetic yoke (61); the center of the flat movable contact (4) is connected to one end of the final pressure spring (7); the other end of the final pressure spring (7) is connected to the bottom of the lower magnetic yoke (61); and the two ends of the flat movable contact (4) are respectively connected to the lead-out ends of the static contact (1).

3. The short-circuit-resistant DC contactor according to claim 2, characterized in that: The upper armature (51) is a trapezoidal structure, and a notch is formed at the upper portion of the lower magnetic yoke (61) corresponding to the trapezoidal structure, and the upper armature (51) is arranged in the notch to realize magnetic conduction.

4. The short-circuit-resistant DC contactor according to claim 2, characterized in that: One end of the lower magnetic yoke connecting rod (63) is connected to the lower portion of the lower magnetic yoke (61), and the other end passes through the lower support plate (8) and is arranged in the moving iron core (9).

5. The short-circuit-resistant DC contactor according to claim 1, characterized in that: The reset device comprises a torsion spring or a reset spring leaf, wherein the torsion spring is arranged at the rotating shaft, and the reset spring leaf is arranged at the center of the upper armature (51).

6. The short-circuit-resistant DC contactor according to claim 1, characterized in that: A lower yoke connecting block (62) is arranged on the lower support plate (8), the lower yoke (61) is arranged on the lower yoke connecting block (62), and the other end of the lower yoke connecting rod (63) passes through the lower yoke connecting block (62) and the lower support plate (8) and is then arranged in the moving iron core (9).

7. The short-circuit-resistant DC contactor according to claim 1, characterized in that: A U-shaped magnetic yoke (10) is correspondingly arranged on the outside of each group of magnetic steel sheets (3), the magnetic steel sheets (3) are adsorbed and connected to the U-shaped magnetic yoke (10), and the inside of each group of magnetic steel sheets (3) is placed according to NN or SS.

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