DC relay that can withstand short circuit current and extinguish arcs

Abstract

To provide a DC relay having short circuit resistance and capable of extinguishing an arc.SOLUTION: A DC relay includes two stationary contact lead-out ends 1, a movable contact piece 2 in the form of a straight sheet, a push rod assembly 3, an upper fixed yoke 4, an upper follower yoke 5, and a lower armature 6. The upper fixed yoke 4 is fixed to the upper side of the push rod assembly 3 and positioned above the movable contact piece 2 in a location corresponding to a location between two movable contacts. The upper follower yoke 5 is fixed to the push rod assembly 3 and positioned above the movable contact piece 2 in a location corresponding to the location between the two movable contacts. The lower armature 6 is fixed to a bottom end surface of the movable contact piece 2. The upper fixed yoke 4, the upper follower yoke 5 and the lower armature 6 are respectively arranged in a width direction of the movable contact piece 2, and two magnetic rings are formed in the width direction of the movable contact piece 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (Cross-reference of related applications) This disclosure claims priority to Chinese Patent Application Nos. 201911422798.8 and 201911422791.6, filed on December 31, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the field of relay technology, and more particularly to a DC relay capable of withstanding short circuit current and extinguishing arcs. [Background technology]

[0003] The short-circuit resistance of DC relays is currently a difficult indicator, and in high-voltage DC relays, the short-circuit current has reached a level of 16kA. When a short-circuit current passes through the moving and static contacts, the electromotive repulsive force generated between the moving and static contacts causes the contacts to separate, eventually causing a violent arc and causing the relay to fail. The fundamental solution to low short-circuit resistance is to ensure reliable contact between the contacts and prevent them from separating.

[0004] In the prior art, a magnetic ring made of an upper yoke and a lower armature is usually attached to the movable contact piece, and when a short-circuit current flows through the movable contact piece, a ring magnetic field is generated around the movable contact piece, and when the ring magnetic field acts on the upper yoke and the lower armature, an attractive force is generated on the upper yoke and the lower armature. The upper yoke is fixed to the inside of the bottom wall of the U-shaped bracket of the push rod assembly, and the lower armature is fixed to the bottom surface of the movable contact piece, so that the magnetic ring made of the upper yoke and the lower armature generates an attractive force on the movable contact piece in the pressure direction of the contact, and the movable contact and the static contact are not separated. The larger the short-circuit current, the denser the magnetic induction line acting on the magnetic ring becomes, and at this time, when the magnetic induction line increases instantaneously, a larger electromagnetic attractive force is generated between the upper yoke and the lower armature. In this type of short circuit resistant configuration, the upper yoke is fixed to the U-shaped bracket of the push rod assembly, and the upper yoke also moves with the movement of the push rod assembly, and during the overtravel stage, the moving contact and the static contact come into contact, and the push rod assembly continues to move upward, and the spring is compressed to form a contact pressure, and since the upper yoke is fixed inside the bottom wall of the U-shaped bracket of the push rod assembly, a gap is generated between the upper yoke and the lower armature, and the electromagnetic attraction force is weak. Since the upper yoke is fixed to the cooperating push rod, the push rod is made stationary by the attraction force of the iron core, and when the short circuit current reaches a certain level, the electromagnetic attraction force generated between the short circuit link ring is also very large, for example, reaching 105N. At this time, the attraction force generated by the coil of the iron core is only 100N, and the relay does not hold the iron core, the iron core is released, and the contacts are separated.

[0005] On the other hand, high voltage DC relays with a conventional direct acting magnetic circuit structure usually perform arc extinguishing by magnetic blow, that is, magnetic steel is arranged around the contacts of two movable contacts and a static contact, and the magnetic field formed by the magnetic steel is used to perform arc extinguishing by magnetic blow. Arc extinguishing by magnetic blow is useful for extinguishing the arc of the relay and improving its lifespan, but there is a problem that the energized movable contact is subjected to Lorentz force by the arc extinguishing magnetic field caused by magnetic blow. Due to the arrangement of the arc extinguishing magnetic circuit by magnetic blow, the Lorentz force that the movable contact receives from the arc extinguishing magnetic field by magnetic blow is directed downward. Thus, the force received by the movable contact is the sum of the electric repulsive force and the Lorentz force. If this sum becomes greater than the pressure on the contacts due to overtravel, the movable contact and the static contact (moving contact) cannot make reliable contact and are separated, resulting in failure of arc extinguishing.

[0006] It should be noted that the above information disclosed in the Background section is intended solely to deepen understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] One object of the present invention is to overcome the drawbacks of the prior art and provide a DC relay that can withstand short-circuit current and extinguish arcs, and by using an improved short-circuit-resistant structure, the electromagnetic attraction force can be increased, and as a result, the short-circuit current withstand capability of the DC relay can be significantly improved to the 16kA level.

[0008] A second object of the present invention is to overcome the drawbacks of the prior art and to provide a DC relay that can withstand short-circuit current and extinguish an arc, and by improving the configuration of the arc-extinguishing magnetic circuit, it is possible to eliminate the drawback of the product's reduced short-circuit resistance due to the arc-extinguishing magnetic field.

[0009] As one aspect of the present invention, there is provided a DC relay capable of withstanding a short circuit current and extinguishing an arc, comprising: a drawn-out end of two static contacts; a straight sheet-shaped movable contact piece; and a push rod assembly, the movable contact piece is attached to the push rod assembly, and the push rod assembly operates the movable contacts at both ends of the movable contact piece and the two static contacts at the bottom ends of the drawn-out ends of the two static contacts. Here, the DC relay further comprises a fixed upper yoke, a driven upper yoke, and a lower armature, the fixed upper yoke is fixed above the push rod assembly and located above a position between the two movable contacts of the movable contact piece, the driven upper yoke is fixed to the push rod assembly and located above a position between the two movable contacts of the movable contact piece, the lower armature is fixed to a bottom end surface of the position between the two movable contacts of the movable contact piece, and the fixed upper yoke, the driven upper yoke, and the lower armature are connected to each other. are distributed along the width direction of the movable contact piece, and when the movable contact comes into contact with the static contact, the lower armature is brought close to or into contact with the fixed upper yoke and the driven upper yoke, respectively, to form two magnetic rings in the width direction of the movable contact piece.When a large fault current occurs in the movable contact piece, the two magnetic rings generate an electromagnetic attractive force to maintain contact between the movable contact and the static contact, and can counter the electromotive repulsive force generated by the fault current between the movable contact piece and the pull-out end of the static contact.

[0010] According to one embodiment of the present invention, wherein the two magnetic rings overlap.

[0011] According to one embodiment of the present invention, wherein the push rod assembly includes a first U-shaped bracket, a spring, a spring seat and a push rod, an upper portion of the push rod is fixed to the spring seat, the first U-shaped bracket is inverted U-shaped and includes two opposing side walls and a bottom wall to which ends of the two side walls are connected, the bottom wall of the first U-shaped bracket is fixed to the spring seat, the driven upper yoke is fixed inside the bottom wall of the first U-shaped bracket, and the spring abuts between the lower armature at the bottom end of the movable contact piece and the spring seat.

[0012] According to one embodiment of the present invention, wherein a mounting slot is provided at a bottom end of the lower armature for mounting the spring, and the thickness of the lower armature is greater than the thickness of the driven upper yoke.

[0013] According to one embodiment of the present invention, the fixed upper yoke and the driven upper yoke are each shaped like a letter, the lower armature is shaped like a letter U and includes two opposing side walls and a bottom wall to which the ends of the two side walls are connected, and a through hole is provided in the bottom wall of the first U-shaped bracket, so that the two side walls of the lower armature pass through the through hole and protrude upward to contact or be close to the fixed upper yoke, and a magnetic ring is formed in which two parts of the lower armature, the fixed upper yoke, and the driven upper yoke overlap each other.

[0014] According to one embodiment of the present invention, a step is provided at the end of each side wall of the lower armature, and a convex portion is formed at the high part of the step, and the convex portion passes through a through hole in the bottom wall of the first U-shaped bracket and contacts or is adjacent to the fixed upper yoke to form one magnetic ring, and the steps on both side walls of the lower armature contact or are adjacent to the driven upper yoke, respectively, to form another magnetic ring, and the two magnetic rings overlap the lower armature.

[0015] According to one embodiment of the present invention, recesses are provided at both ends of the driven upper yoke for retracting the protrusions of the lower armature, and bosses are provided inside the recesses to engage with through holes in the bottom wall of the first U-shaped bracket.

[0016] According to one embodiment of the present invention, wherein the DC relay further includes a yoke plate, the yoke plate is provided with a through hole, a first U-shaped bracket, a spring and a spring seat of the push rod assembly are positioned on the yoke plate, the push rod of the push rod assembly passes through the through hole of the yoke plate and is fixed to a movable core below the yoke plate, a second U-shaped bracket having an inverted U shape is attached to the yoke plate, the second U-shaped bracket includes two opposing side walls and a bottom wall connected to ends of the two side walls, and the fixed upper yoke is fixed to an inside of the bottom wall of the second U-shaped bracket.

[0017] According to one embodiment of the present invention, wherein said second U-shaped bracket is made of diamagnetic or weakly magnetic material.

[0018] According to one embodiment of the present invention, wherein the thickness of the fixed upper yoke is equal to or greater than the thickness of the lower armature.

[0019] According to one embodiment of the present invention, in the DC relay, two magnetic steels for arc extinguishing are provided next to the movable contact, the two magnetic steels are provided at both ends of the movable contact piece in the longitudinal direction, respectively, with a gap provided between each of them and the movable contact piece, the two magnetic steels are provided at positions adjacent to the two movable contacts of the movable contact piece, and the magnetic poles of the opposing surfaces of the two magnetic steels are opposite.

[0020] According to one embodiment of the present invention, the DC relay further includes two U-shaped yoke clamps, each of the U-shaped yoke clamps including two opposing side walls and a bottom wall connected to one end of the two side walls, the two bottom walls of the two yoke clamps being respectively connected to opposing surfaces of two magnetic steels, and the ends of the two side walls of each of the yoke clamps being positioned opposite to the adjacent movable contact.

[0021] According to one embodiment of the present invention, wherein the DC relay further includes two U-shaped yoke clamps, each of the U-shaped yoke clamps includes two opposing side walls and a bottom wall connected to one end of the two side walls, the two bottom walls of the two yoke clamps are respectively connected to opposing surfaces of two magnetic steels, the ends of the two side walls of each of the yoke clamps exceed positions facing adjacent movable contacts, and the side walls of the two yoke clamps are adjacent to each other at a central position between the two movable contacts of the movable contact piece.

[0022] According to one embodiment of the present invention, wherein the DC relay further includes two U-shaped yoke clamps, each of the U-shaped yoke clamps includes two opposing side walls and a bottom wall connected to one end of the two side walls, the two bottom walls of the two yoke clamps are respectively provided on both sides in the width direction of the movable contact piece, and the ends of the side walls of the two yoke clamps are respectively connected to the opposing surfaces of the two magnetic steel pieces.

[0023] According to one embodiment of the present invention, the DC relay further includes three magnetic steels, a first magnetic steel, a second magnetic steel and a third magnetic steel, for extinguishing an arc adjacent to the contacts, the first magnetic steel and the second magnetic steel are respectively arranged on both sides of the width direction of the movable contact piece, adjacent to one of the two movable contacts of the movable contact piece, the magnetic poles of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact are the same, and the third magnetic steel is arranged on one side of the length direction of the movable contact piece, adjacent to the other of the two movable contacts of the movable contact piece, and the pole surface of the third magnetic steel is approximately perpendicular to the pole surfaces of the first magnetic steel and the second magnetic steel.

[0024] According to one embodiment of the present invention, since the magnetic pole of the surface of the third magnetic steel facing the movable contact is the same as the magnetic pole of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact, the blow arc directions at the two movable contacts of the extinguishing magnetic field formed by the three magnetic steels face in opposite outward directions.

[0025] According to one embodiment of the present invention, wherein the DC relay further includes two U-shaped yoke clamps, each of the U-shaped yoke clamps includes two opposing side walls and a bottom wall connected to one end of the two side walls, the two side walls of one of the yoke clamps are connected to the surfaces of the first magnetic steel and the second magnetic steel facing away from the movable contact, respectively, the bottom wall of the other of the yoke clamps is connected to the surface of the third magnetic steel facing away from the movable contact, and the two side walls are respectively located on both sides of the width direction of the movable contact piece.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. In the present invention, a DC relay is provided with a fixed upper yoke, a driven upper yoke and a lower armature, the fixed upper yoke is fixed above the push rod assembly and located above the position between the two movable contacts of the movable contact piece, the driven upper yoke is fixed to the push rod assembly and located above the position between the two movable contacts of the movable contact piece, the lower armature is fixed to the bottom end surface of the position between the two movable contacts of the movable contact piece, the fixed upper yoke, the driven upper yoke and the lower armature are respectively distributed along the width direction of the movable contact piece, and when the movable contacts contact the static contacts, both ends of the lower armature are respectively close to or in contact with both ends of the fixed upper yoke and the driven upper yoke, so that two magnetic rings are formed in the width direction of the movable contact piece. With this structure of the present invention, when a fault occurs in the moving contact due to a large current, the two magnetic rings generate an electromagnetic attraction force in the same direction as the contact pressure, i.e., a force is generated that maintains contact between the moving contact and the static contact, which can counter the electromotive repulsive force generated by the fault current between the moving contact and the pull-out end of the static contact. This greatly improves the short-circuit resistance of the product, and the short-circuit resistance current can reach a level of 16kA.

[0028] In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke and a lower armature has stronger short-circuit resistance than the configuration consisting of a driven upper yoke and a lower armature. In the case of the configuration consisting of a driven upper yoke and a lower armature, the upper yoke is fixed to the push rod which cooperates with it, and the push rod is stationary by relying on the attractive force of the iron core, so when the short-circuit current becomes large to a certain extent, the electromagnetic attractive force generated between the short-circuit rings is also large, for example reaching 105N, while the attractive force by the coil of the iron core is only 100N, and the relay does not hold the iron core, the iron core is released, and the contacts are separated. In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke, and a lower armature uses part of the attractive force as a holding force for the iron core, and the other part is assigned to the fixed yoke, and the driven upper yoke can offset part of the attractive force between the driven upper yoke and the lower armature when the limiting current is interrupted by magnetic short-circuiting, which is advantageous for current interruption. Although the driven upper yoke affects the turn-on of the current when the load is turned on, because the thickness of the driven upper yoke is thin and the attractive force generated is small, the effect on the turn-on of the current is small and there is no direct effect on the normal turn-on of the DC relay.

[0029] 2. In the present invention, two magnetic steels for arc extinction are arranged next to the movable contact, and the two magnetic steels are arranged at both ends of the movable contact piece in the longitudinal direction, respectively, adjacent to the positions of the two movable contacts, and the magnetic poles of the opposing surfaces of the two magnetic steels are opposite. This structure of the present invention not only realizes arc extinction by the magnetic steels, but also makes the Lorentz force generated by the arc extinction magnetic field formed by the two magnetic steels of the movable contact piece almost zero, and improves short-circuit resistance against short-circuit current.

[0030] 3. In the present invention, three magnetic steels for arc extinction are arranged next to the movable contact, and the first magnetic steel and the second magnetic steel of the three magnetic steels are arranged on the outside of both sides in the width direction of the movable contact piece, respectively, and are located in close proximity to one of the two movable contacts of the movable contact piece, and the magnetic poles of the first magnetic steel and the second magnetic steel facing the movable contact are the same, and the third magnetic steel of the three magnetic steels is arranged on one side in the length direction of the movable contact piece, and is located in close proximity to the other of the two movable contacts of the movable contact piece, and the pole face of the third magnetic steel is almost perpendicular to the pole faces of the first magnetic steel and the second magnetic steel. With the configuration of the present invention, in addition to realizing arc extinction by magnetic steel, it is also possible to make the Lorentz force generated in the extinction magnetic field formed by the three magnetic steels of the movable contact piece almost zero, and short-circuit resistance against short-circuit current can be improved.

[0031] The present invention will be described in more detail below with reference to the drawings and examples. However, the DC relay capable of withstanding a short circuit current and extinguishing an arc according to the present invention is not limited to the examples. [Brief description of the drawings]

[0032] The above and other features and advantages of the present invention will become more apparent from the following detailed description of illustrative embodiments thereof, taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of a partial configuration of a first embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of a partial configuration (angle rotation) of the first embodiment of the present invention; [Diagram 3] FIG. 2 is an exploded view of a portion of the configuration of the first embodiment of the present invention. [Figure 4] FIG. 2 is a top view of a partial configuration of the first embodiment of the present invention. [Diagram 5] FIG. 2 is a front view of a partial configuration of the first embodiment of the present invention. [Figure 6] 6 is a cross-sectional view taken along line AA in FIG. 5. [Figure 7] FIG. 2 is a schematic diagram of a configuration including a fixed upper yoke, a driven upper yoke, and a push rod assembly in the first embodiment of the present invention. [Figure 8]FIG. 2 is a schematic diagram of a configuration including a driven upper yoke, a movable contact piece, a lower armature, and a push rod assembly in the first embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram of a configuration of a driven upper yoke in the first embodiment of the present invention. [Figure 10] FIG. 2 is a schematic diagram showing the configuration of a first U-shaped bracket in the first embodiment of the present invention. [Figure 11] FIG. 2 is a schematic diagram of a configuration of a lower armature in the first embodiment of the present invention. [Figure 12] FIG. 11 is a schematic diagram of a partial configuration of a second embodiment of the present invention. [Figure 13] FIG. 11 is an exploded view of a portion of the configuration of the second embodiment of the present invention. [Figure 14] FIG. 11 is a top view of a partial configuration of the second embodiment of the present invention. [Figure 15] FIG. 11 is a front view of a partial configuration of the second embodiment of the present invention. [Figure 16] 16 is a cross-sectional view taken along line BB in FIG. 15. [Figure 17] FIG. 11 is a schematic diagram of a partial configuration of the third embodiment of the present invention. [Figure 18] FIG. 11 is an exploded view of a portion of the configuration of the third embodiment of the present invention. [Figure 19] FIG. 13 is a top view of a partial configuration of the third embodiment of the present invention. [Figure 20] FIG. 11 is a front view of a partial configuration of the third embodiment of the present invention. [Figure 21] 21 is a cross-sectional view taken along line CC in FIG. 20. [Figure 22] FIG. 13 is a schematic diagram of a partial configuration of a fourth embodiment of the present invention. [Figure 23] FIG. 13 is a top view of a partial configuration of the fourth embodiment of the present invention. [Figure 24] 24 is a cross-sectional view of the line DD in FIG. 23. [Diagram 25] FIG. 13 is a schematic diagram of a partial configuration of the fifth embodiment of the present invention. [Figure 26] FIG. 13 is an exploded view of a portion of the configuration of the fifth embodiment of the present invention. [Figure 27] FIG. 13 is a top view of a partial configuration of the fifth embodiment of the present invention. [Figure 28]FIG. 13 is a top view of a portion of the configuration of the fifth embodiment of the present invention (forward current). [Figure 29] FIG. 13 is a top view of a portion of the configuration of the fifth embodiment of the present invention (reverse current). [Diagram 30] FIG. 13 is a schematic diagram of a partial configuration of the sixth embodiment of the present invention. [Diagram 31] FIG. 13 is an exploded view of a portion of the configuration of the sixth embodiment of the present invention. [Diagram 32] FIG. 13 is a schematic diagram of a configuration consisting of a movable contact piece, an upper yoke, a lower armature and a push rod assembly in a sixth embodiment of the present invention. [Diagram 33] FIG. 13 is an exploded view of a portion of a configuration including a movable contact piece, an upper yoke, a lower armature, and a push rod assembly in a sixth embodiment of the present invention. [Diagram 34] FIG. 13 is a schematic diagram of a configuration including a movable contact piece, an upper yoke, and a lower armature in a sixth embodiment of the present invention. [Diagram 35] FIG. 13 is a schematic diagram of a configuration including a movable contact piece, an upper yoke, and a lower armature in the sixth embodiment of the present invention (another angle). [Diagram 36] FIG. 13 is a schematic diagram of a configuration consisting of a first U-shaped bracket and an upper yoke in a sixth embodiment of the present invention. [Figure 37] FIG. 13 is a schematic diagram of a configuration consisting of a movable contact piece and a lower armature in a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Next, the illustrated embodiment will be described in more detail with reference to the accompanying drawings. However, the illustrated embodiment may be implemented in various forms and should not be construed as being limited to the embodiments described herein. In this specification, relative terms such as "upper" and "lower" are used to describe the relative relationship between a certain component and another component, but these terms are used only for convenience, for example according to the orientation of the embodiment described in the accompanying drawings. It is understood that when the device shown by the reference numeral is rotated upside down, the part described as "upper" becomes the part described as "lower". Other relative terms such as "top" and "bottom" are used in the same sense. When a structure is "on" another structure, it can mean that the structure is integrally formed on the other structure, that the structure is "directly" set on the other structure, or that the structure is "indirectly" set on the other structure through the other structure.

[0034] The terms "a," "an," "the," and "said" are used to indicate the presence of one or more elements / components etc. The terms "including" and "having" are used to indicate an open-ended inclusiveness and mean that there may be additional elements / components etc. other than the listed elements / components etc. The terms "first," "second," "third," etc. are used as indicative only and do not limit the number of objects.

[0035] Example 1 As shown in Figs. 1 to 11, the DC relay capable of withstanding short circuit current and extinguishing arc in this embodiment 1 includes two static contacts drawn-out ends 1, one straight sheet-shaped movable contact piece 2, and one push rod assembly 3. The movable contact piece 2 is attached to the push rod assembly 3, whereby the action of the push rod assembly 3 realizes the operation of two movable contacts at both ends of the movable contact piece 2 and two static contacts at the bottom ends of the drawn-out ends 1 of the two static contacts. In this embodiment 1, the two movable contacts of the movable contact piece 2 are formed at both ends of the movable contact piece 2, and the static contacts of the drawn-out ends 1 of the static contacts are formed at the bottom ends of the drawn-out ends 1 of the static contacts.

[0036] As shown in FIG. 1, FIG. 2, FIG. 3 and FIG. 6, in this embodiment, the DC relay further includes one fixed upper yoke 4, one driven upper yoke 5 and one lower armature 6. The fixed upper yoke 4 is fixed above the push rod assembly 3, located above the movable contact 2, and corresponds to a position between two movable contacts of the movable contact 2. The driven upper yoke 5 is fixed to the push rod assembly 3, located above the movable contact 2, and located below the fixed upper yoke 4, and corresponds to a position between two movable contacts of the movable contact 2. The lower armature 6 is fixed to the bottom end surface of the movable contact 2, and corresponds to a position between two movable contacts of the movable contact 2. The fixed upper yoke 4, the driven upper yoke 5 and the lower armature 6 are distributed along the width direction W of the movable contact 2. When the movable contact comes into contact with the static contact, both ends of the lower armature 6 are close to or in contact with both ends of the fixed upper yoke 4 and the driven upper yoke 5, respectively, thereby forming a magnetic ring whose two parts overlap in the width direction W of the movable contact piece 2. When a large fault current occurs in the movable contact piece 2, an electromagnetic attractive force coincident with the direction of the contact pressure is generated in the magnetic ring, which can counteract the electromotive repulsive force generated by the fault current between the movable contact piece 2 and the lead-out end 1 of the static contact.

[0037] 3 and 10, in this embodiment, the push rod assembly 3 includes a first U-shaped bracket 31, a spring 32, a spring seat 33 and a push rod 34. An upper portion of the push rod 34 is fixed to the spring seat 33, and the first U-shaped bracket 31 is inverted U-shaped and includes two opposing side walls 310 and a bottom wall 311 connected to one end of the two side walls 310, and the bottom wall 311 is fixed to the spring seat 33. The driven upper yoke 5 is fixed to the inside of the bottom wall 311 of the first U-shaped bracket 31, and the spring 32 abuts between the lower armature 6 at the bottom end of the movable contact piece 2 and the spring seat 33.

[0038] 3 and 11, in this embodiment, a mounting slot 61 for mounting the spring is provided at the bottom end of the lower armature 6. The thickness T1 of the lower armature 6 is greater than the thickness T2 of the driven upper yoke 5.

[0039] As shown in Figures 10 and 11, in this embodiment, the fixed upper yoke 4 and the driven upper yoke 5 are each shaped like a straight line. The lower armature 6 is U-shaped and includes two opposing side walls 65 and a bottom wall 66 connected to one end of the two side walls 65. A through hole 312 is provided in the bottom wall 311 of the first U-shaped bracket 31, and both side walls 65 of the lower armature 6 pass through the through hole 312 and contact or approach the upper fixed upper yoke 4. The lower armature 6, the fixed upper yoke 4, and the driven upper yoke 5, which are shaped like a straight line, form a magnetic ring in which two parts overlap each other.

[0040] As shown in Figures 9 and 11, in this embodiment 1, a step 62 is further provided on the upper part of both side walls 65 of the lower armature 6, and a convex portion 63 is formed at the high part of the step 62, and the convex portion 63 passes through the through hole 312 of the bottom wall 311 of the first U-shaped bracket 31 and contacts or is close to the fixed upper yoke 4 to form one magnetic ring, and the steps 62 of both side walls 65 of the lower armature 6 contact or are close to the driven upper yoke 5 to form another magnetic ring, and the two magnetic rings overlap the lower armature 6.

[0041] As shown in Figures 9 and 11, in this embodiment, recesses 51 for retracting the protrusions 63 of the lower armature 6 are provided on both ends of the driven upper yoke 5, and bosses 52 for engaging with the through holes 312 of the bottom wall 311 of the first U-shaped bracket 31 are provided on the inside of the recesses 51.

[0042] As shown in Figures 3, 6 and 7, in this embodiment, the DC relay further includes a yoke plate 71, and the yoke plate 71 is provided with a through hole 711. The first U-shaped bracket 31, the spring 32 and the spring seat 33 of the push rod assembly are located on the yoke plate 71. The push rod 34 of the push rod assembly passes through the through hole 711 of the yoke plate 71 downward and is fixed to the movable core under the yoke plate. The yoke plate 71 is provided with a second U-shaped bracket 72 having an inverted U shape, and includes two opposing side walls 722 and a bottom wall 721 connected to one end of the two side walls 722. The fixed upper yoke 4 is fixed to the inside of the bottom wall 721 of the second U-shaped bracket 72.

[0043] The second U-shaped bracket 72 is made of diamagnetic or weakly magnetic material, such as non-magnetic stainless steel, aluminum, etc.

[0044] 3, in this embodiment, the thickness T3 of the fixed upper yoke 4 is greater than the thickness T1 of the lower armature 6. By increasing the thickness T3 of the fixed upper yoke 4, the attractive force of the fixed upper yoke 4 can be increased.

[0045] In the DC relay of this embodiment, when the push rod assembly 3 does not move upward, the upper surface of the movable contact piece 2 abuts against the bottom surface of the driven upper yoke 5 due to the action of the spring 32, and when the push rod assembly 3 moves to an appropriate position, the two movable contacts at both ends of the movable contact piece 2 contact the bottom ends of the drawn-out ends 1 of the two static contacts, respectively. At this time, the steps 62 on both side walls of the lower armature 6 contact the driven upper yoke 5, respectively, and the protrusions 63 on both side walls of the lower armature 6 contact or are close to the fixed upper yoke 4, respectively. Then, the push rod assembly 3 continues to move upward, and the driven upper yoke 5 moves upward together with the push rod assembly 3, and the movable contact piece 2 has already contacted the bottom ends of the pull-out ends 1 of the two static contacts, so that the movable contact piece 2 cannot continue to move upward, resulting in overtravel of the contacts, and the contact pressure is provided by the spring 32, and a certain gap is formed between the bottom end of the driven upper yoke 5 and the upper surface of the movable contact piece 2, so that a magnetic gap is formed between the bottom surface of the driven upper yoke 5 and the upper surface of the lower armature 6.

[0046] In the present invention, this configuration makes it possible to increase the attractive force against the lower armature 6 by utilizing the fixed upper yoke 4. For example, the thickness of the fixed upper yoke 4 can be increased to increase the magnetic attractive force, or the driven upper yoke 5 can be used to magnetically short-circuit a portion of the attractive force when the limiting current is interrupted, making interruption easier. In the DC relay capable of withstanding short circuit current and extinguishing arc in this embodiment 1, the DC relay is provided with one fixed upper yoke 4, one driven upper yoke 5 and one lower armature 6, the fixed upper yoke 4 is fixed on the corresponding push rod assembly 3 between two movable contacts of the movable contact piece 2, the driven upper yoke 5 is fixed to the push rod assembly 3 on the movable contact piece 2 corresponding to said position, the lower armature 6 is fixed to the bottom end surface of the movable contact piece 2 corresponding to said position, the fixed upper yoke 4, the driven upper yoke 5 and the lower armature 6 are respectively distributed along the width direction of the movable contact piece 2, and when the contacts come into contact, both ends of the lower armature 6 are brought close to or into contact with both ends of the fixed upper yoke 4 and the driven upper yoke 5, respectively, thereby forming a magnetic ring having two overlapping parts in the width direction of the movable contact piece 2.

[0047] With this configuration of the present invention, when a large fault current occurs in the movable contact 2, an electromagnetic attractive force is generated in the direction of the contact pressure, which can counter the electromotive repulsive force generated by the fault current between the movable contact and the pull-out end of the static contact. The present invention significantly improves the short-circuit resistance of the product, making it capable of withstanding a short-circuit current of up to 16kA.

[0048] In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke and a lower armature has stronger short-circuit resistance than the configuration consisting of a driven upper yoke and a lower armature. In the case of the configuration consisting of a driven upper yoke and a lower armature, the upper yoke is fixed to the push rod which cooperates with it, and the push rod is stationary by the magnetic force of the iron core, so when the short-circuit current becomes large to a certain extent, the electromagnetic magnetic force generated between the short-circuit rings is also large, for example reaching 105N, and at this time, the magnetic force of the coil of the iron core is only 100N, and the relay does not hold the iron core, the iron core is released, and the contacts are separated. In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke and a lower armature uses part of the magnetic force as the magnetic force of the iron core and the other part as the fixed yoke, and the driven upper yoke can offset part of the magnetic force at the time of breaking the limit current by magnetic short circuit, which is advantageous for breaking the current, because the influence of the load on the driven upper yoke on the magnetic force is small and its thickness is small.

[0049] Example 2 As shown in Figs. 12 to 16, the DC relay capable of withstanding a short circuit current and extinguishing an arc in the second embodiment differs from the first embodiment in that a magnetic steel member 81 for extinguishing an arc is further provided next to the contact.

[0050] As shown in Figure 13, there are two magnetic steel pieces 81 for extinguishing the arc, and the two magnetic steel pieces 81 are provided on the outside of both ends of the movable contact piece 2 in the longitudinal direction L, located in close proximity to the two movable contacts of the movable contact piece 2, and the magnetic poles of the opposing surfaces of the two magnetic steel pieces 81 are opposite.

[0051] 13 and 14, in this embodiment 2, the DC relay further includes two U-shaped yoke clamps 82, and the U-shaped yoke clamp 82 includes two opposing side walls 822 and a bottom wall 821 connected to one end of the two side walls 822. The bottom walls 821 of the two yoke clamps 82 are respectively connected to the opposing surfaces of the two magnetic steel pieces 81, and the ends of the both side walls 822 of the two yoke clamps 82 exceed positions corresponding to the adjacent movable contacts and approach each other at a central position between the two movable contacts.

[0052] In the DC relay capable of withstanding a short circuit current and extinguishing an arc in this second embodiment, a magnetic steel plate 81 for extinguishing an arc is further arranged next to the contact, there are two magnetic steel plates 81 for extinguishing an arc, the two magnetic steel plates 81 are arranged at positions corresponding to the movable contacts outside both ends in the longitudinal direction of the movable contact piece 2, and the magnetic poles of the opposing faces of the two magnetic steel plates 81 are opposite. With this configuration of the present invention, in addition to realizing arc extinguishing by the magnetic steel plates, the Lorentz force generated in the arc extinguishing magnetic field formed by the two magnetic steel plates of the movable contact piece becomes almost zero, and short circuit resistance against a short circuit current can be improved.

[0053] Example 3 As shown in Figures 17 to 21, the DC relay capable of withstanding a short circuit current and extinguishing an arc in the third embodiment differs from the first embodiment in that a magnetic steel 81 for extinguishing an arc is further disposed next to the contact.

[0054] As shown in Figs. 18 and 19, there are three magnetic steels 81 for extinguishing the arc, and a first magnetic steel and a second magnetic steel of the three magnetic steels 81 are arranged on both sides of the width direction W of the movable contact piece 2. The first magnetic steel and the second magnetic steel are spaced apart from the movable contact piece 2. The first magnetic steel and the second magnetic steel are located at positions corresponding to one movable contact (right side) of the two movable contacts of the movable contact piece 2, and the magnetic poles of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact are the same. The third magnetic steel of the three magnetic steels 81 is located on one side of the length direction L of the movable contact piece 2, and is located adjacent to the other movable contact (left side) of the two movable contacts of the movable contact piece 2, and the pole face of the third magnetic steel (left side) is approximately perpendicular to the pole faces of the first magnetic steel and the second magnetic steel (right side).

[0055] In this third embodiment, the magnetic pole facing the movable contact of the third magnetic steel (left side) is the same as the magnetic pole of the surfaces facing the movable contacts of the first magnetic steel and the second magnetic steel (right side), so that the blow arc directions of the two movable contacts of the extinguishing magnetic field formed by the three magnetic steels 81 face outward in opposite directions.

[0056] As shown in Fig. 18 to Fig. 20, the DC relay in the second embodiment further includes two U-shaped yoke clamps 82. Each of the U-shaped yoke clamps 82 includes two opposing side walls 822 and a bottom wall 821 connected to one end of the two side walls 822. Here, both side walls 822 of one yoke clamp 82 (right side) are connected to the surfaces facing the movable contacts of the first magnetic steel and the second magnetic steel (right side), respectively, and the bottom wall 821 is located on the right side in the length direction of the movable contact piece 2, and the bottom wall 821 of the other yoke clamp 82 (left side) is connected to the surface facing the movable contact of the third magnetic steel (left side), and both side walls 822 are located on both sides in the width direction of the movable contact piece 2, respectively, and correspond to the other movable contact (left side).

[0057] In the DC relay capable of withstanding a short circuit current and extinguishing an arc in the third embodiment, a magnetic steel 81 for extinguishing an arc is further arranged next to the contact. Here, there are three magnetic steels 81 for extinguishing an arc, and a first magnetic steel and a second magnetic steel 81 of the three magnetic steels 81 are arranged on the outside of both sides in the width direction of the movable contact piece 2, respectively, one of which is located at a position corresponding to the movable contact (right side), and the magnetic poles of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact are the same. A third magnetic steel of the three magnetic steels 81 is arranged on the outside of one side (left side) in the length direction of the movable contact piece 2, located at a position relative to the other movable contact (left side), and the pole surface of the third magnetic steel 81 (left side) is approximately perpendicular to the pole surfaces of the first magnetic steel and the second magnetic steel 81 (right side). This configuration of the present invention not only achieves arc extinction using magnetic steel, but also makes the Lorentz force generated in the arc extinction magnetic field formed by the three magnetic steel pieces 81 of the movable contact piece almost zero, thereby improving short-circuit resistance against short-circuit currents.

[0058] In addition, the arc extinction configurations of magnetic steel in conventional DC relays are an arc extinction configuration using two magnetic steel pieces and an arc extinction configuration using four magnetic steel pieces. In the conventional technology, the arc extinction configuration using four magnetic steel pieces is such that the four magnetic steel pieces are arranged at positions corresponding to the movable contacts on both sides of the width direction of the movable contact piece, and the surfaces of the two magnetic steel pieces corresponding to the same movable contact piece facing the movable contact have opposite magnetic poles, and the surfaces of the two magnetic steel pieces corresponding to the same side of the width direction of the movable contact piece facing the corresponding movable contact have the same magnetic poles. The disadvantages of this magnetic steel configuration are that, firstly, the Lorentz force that the movable contact piece receives from the arc extinction magnetic field caused by the magnetic blow is downward, which affects the reliable contact between the movable contacts, causing them to separate and fail to extinction, and reducing the short-circuit resistance of the product. Secondly, there is a polarity requirement for the load wiring, and there is a large difference between forward arc extinction and reverse arc extinction.

[0059] Therefore, the present invention provides a DC relay that can withstand short-circuit current and extinguish arcs, and by improving the structure of the arc-extinguishing magnetic circuit, it eliminates the drawback of the reduction in the short-circuit resistance of the product due to the arc-extinguishing magnetic field, while there is no polarity requirement for the load wiring, and the effects of forward and reverse arc-extinguishing are the same.

[0060] According to one aspect of the present invention, a DC relay with short circuit resistance and arc extinction includes two static contacts drawn out, one straight sheet-shaped movable contact piece, one push rod assembly, and three magnetic steel pieces, the movable contact piece is attached to the push rod assembly, so that the operation of the movable contacts at both ends of the movable contact piece and the static contacts at the bottom ends of the drawn out ends of the two static contacts is realized by the action of the push rod assembly, a first magnetic steel piece and a second magnetic steel piece of the three magnetic steel pieces are respectively arranged on both sides in the width direction of the movable contact piece, the first magnetic steel piece and the second magnetic steel piece are respectively spaced apart between the movable contact pieces, and the The first magnetic steel and the second magnetic steel are adjacent to one of the two movable contacts of the movable contact piece, the magnetic poles of the surfaces of the first magnetic steel and the second magnetic steel facing the adjacent movable contact are the same, a third magnetic steel of the three magnetic steels is arranged on one side of the length direction of the movable contact piece, a gap is provided between the third magnetic steel and the movable contact piece, the third magnetic steel is adjacent to the other of the two movable contacts of the movable contact piece, and the pole face of the third magnetic steel is approximately perpendicular to the pole faces of the first magnetic steel and the second magnetic steel, so that the Lorentz force generated in the extinguishing magnetic field formed by the movable contact piece and the three magnetic steels is approximately zero.

[0061] In one embodiment, the magnetic pole of the surface of the third magnetic steel facing the movable contact is the same as the magnetic pole of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact, so that the blow arc directions at the two movable contacts of the arc-extinguishing magnetic field formed by the three magnetic steels face in opposite outward directions, respectively.

[0062] In one embodiment, the DC relay further includes two U-shaped yoke clamps, each of which includes two opposing side walls and a bottom wall connected to one end of the two side walls, wherein the two side walls of one yoke clamp are connected to the surfaces of the first and second magnetic steels facing away from the movable contacts, respectively, and the bottom wall is located on one side of the movable contact piece in the longitudinal direction, and the bottom wall of the other yoke clamp is connected to the surface of the third magnetic steel facing away from the movable contact, and the two side walls are located on the outer sides of both sides in the width direction of the movable contact piece, respectively.

[0063] In one embodiment, the push rod assembly includes a first U-shaped bracket having an inverted U-shape, a spring, a spring seat, and a push rod, an upper portion of the push rod is fixed to the spring seat, the first U-shaped bracket includes two opposing side walls and a bottom wall connected to one ends of the two side walls, the bottom wall of the first U-shaped bracket is fixed to the spring seat, the movable contact piece is attached to the first U-shaped bracket by the spring, and the DC relay is provided with a short-circuit resistant configuration of at least two magnetic rings, and when a large fault current occurs in the movable contact piece, an attractive force is generated in the pressure direction of the contact, which counters the electromotive repulsive force generated by the fault current between the movable contact piece and the drawn-out end of the static contact.

[0064] In one embodiment, the short-circuit resistant structure includes an upper yoke and a lower armature, wherein the upper yoke is fixed to the inside of the bottom wall of the first U-shaped bracket, located on the movable contact piece, and corresponding to a position between two movable contacts of the movable contact piece, the lower armature is fixed to the bottom end surface of the movable contact piece, and corresponding to a position between two movable contacts of the movable contact piece, the upper yoke and the lower armature are distributed along the width direction of the movable contact piece, and on both sides of the width direction of the movable contact piece, the upper yoke and the lower armature are distributed along the width direction of the movable contact piece, and ... At least one through hole is provided in the contact piece, so that the upper yoke and lower armature pass through the through hole and come close to or into contact with each other, and at least two magnetic rings are formed by the upper yoke and lower armature in the width direction of the movable contact piece, and by utilizing the increased magnetic pole surface at the position of the corresponding through hole of each of the magnetic rings, when a large fault current occurs in the movable contact piece, an attractive force is generated in the direction of the contact pressure, and the electromotive repulsive force generated by the fault current between the movable contact piece and the pull-out end of the static contact is countered.

[0065] In one embodiment, the upper yoke is a single linear upper yoke, the lower armature is a plurality of U-shaped lower armatures, the plurality of U-shaped lower armatures and corresponding parts of the linear upper yoke form a plurality of independent magnetic rings, and the two U-shaped lower armatures of two adjacent magnetic rings do not come into contact with each other.

[0066] In one embodiment, the upper yoke is a plurality of linear upper yokes, the lower armatures are a corresponding number of U-shaped lower armatures, the U-shaped lower armatures and the corresponding linear upper yokes form a plurality of independent magnetic rings, and the two U-shaped lower armatures of two adjacent magnetic rings do not contact each other.

[0067] In one embodiment, the plurality of U-shaped lower armatures, the number of which corresponds to the plurality of linear upper yokes, are arranged in a linear fashion along the width direction of the movable contact piece.

[0068] In one embodiment, a plurality of U-shaped lower armatures corresponding to the plurality of line-shaped upper yokes are arranged at intervals along the width direction of the movable contact piece.

[0069] In one embodiment, the upper yoke is one or two straight-shaped upper yokes, the lower armature is two U-shaped lower armatures, the two U-shaped lower armatures are matched with the corresponding parts of the straight-shaped upper yoke or the two straight-shaped upper yokes to form two independent magnetic rings, each side wall of the two U-shaped lower armatures is attached to the corresponding side wall in the width direction of the movable contact piece, the other side walls of the two U-shaped lower armatures pass through the same through hole or through holes at two different positions of the movable contact piece, and there is a gap between the other side walls of the two U-shaped lower armatures.

[0070] In one embodiment, the short-circuit resistant arrangement includes a fixed upper yoke, a driven upper yoke and a lower armature, the fixed upper yoke is fixed at a predetermined fixed position on a first U-shaped bracket, is located above the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, the driven upper yoke is fixed to the inside of a bottom wall of the first U-shaped bracket and can move together with the first U-shaped bracket, the driven upper yoke is located above the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, and the lower armature is fixed to a bottom end surface of the movable contact piece. and corresponds to a position between the two movable contacts of the movable contact piece, the fixed upper yoke, the driven upper yoke and the lower armature are distributed along the width direction of the movable contact piece, and on both sides of the width direction of the movable contact piece, the lower armature is close to or in contact with the fixed upper yoke and the driven upper yoke, and two magnetic rings are formed in the width direction of the movable contact piece by the lower armature, the fixed upper yoke and the driven upper yoke, and when a large fault current occurs in the movable contact piece, an attractive force is generated in the direction of the contact pressure to counteract the electromotive repulsive force generated by the fault current between the movable contact piece and the pull-out end of the static contact.

[0071] In one embodiment, the predetermined fixing point is an inner bottom wall of a case of the relay.

[0072] In one embodiment, the predetermined fixing point is an inner side of a bottom wall of a second U-shaped bracket of an inverted U-shape fixed to a yoke plate of the relay.

[0073] In one embodiment, the fixed upper yoke and the driven upper yoke are each shaped like a straight line, the lower armature is shaped like a U and includes two opposing side walls and a bottom wall connected to one ends of the two side walls, and the bottom wall of the first U-shaped bracket is provided with through holes through which both side walls of the lower armature protrude upward and contact or approach the upper fixed upper yoke, and a magnetic ring is formed in which two parts overlap with each other, the lower armature being shaped like a U, the fixed upper yoke being shaped like a straight line, and the driven upper yoke.

[0074] In one embodiment, steps are further provided on both side walls of the lower armature, and a convex portion is formed at the higher portion of the step, and the convex portion passes through a through hole in the bottom wall of the first U-shaped bracket and contacts or is adjacent to the fixed upper yoke to form one magnetic ring, and the steps on both side walls of the lower armature contact or are adjacent to the driven upper yoke, respectively, to form another magnetic ring, and the two magnetic rings overlap the lower armature.

[0075] In one embodiment, a recess is provided at each end of the driven upper yoke to accommodate the protrusion of the lower armature, and a boss is provided on the inside of the recess to engage with a through hole in the bottom wall of the first U-shaped bracket.

[0076] Compared with the conventional technology, the advantages of the present invention are as follows:

[0077] 1. In the present invention, three magnetic steels are provided at the contacts of a DC relay, and the first and second magnetic steels of the three magnetic steels are arranged on the outside of both sides of the movable contact piece in the width direction, respectively, and are located at the position of one of the movable contact pieces, and the magnetic poles of the surfaces of the first and second magnetic steels facing the movable contact piece are the same, and the third magnetic steel is arranged on the outside of one side of the movable contact piece in the length direction, and is located at a position corresponding to the other movable contact piece, and the pole surface of the third magnetic steel is approximately perpendicular to the pole surfaces of the first and second magnetic steels. With this configuration of the present invention, in addition to realizing arc extinction by the magnetic steels, the Lorentz force generated in the extinction magnetic field formed by the three magnetic steels of the movable contact piece becomes almost zero, and short-circuit resistance against short-circuit current can be improved.

[0078] 2. In the present invention, the magnetic pole of the surface of the third magnetic steel facing the movable contact is the same as the magnetic pole of the surfaces of the first and second magnetic steel facing the movable contact. With this configuration of the present invention, the blow arc directions of the arc-extinguishing magnetic field formed by the three magnetic steels at the two movable contacts are respectively in opposite outward directions, there is no polarity requirement for the load wiring, the effect of forward arc-extinguishing and reverse arc-extinguishing is the same, and the relay is easy to use.

[0079] 3. In the present invention, two U-shaped yoke clamps are added, and the side walls of one of the yoke clamps are connected to the surfaces of the first and second magnetic steels facing the movable contact, respectively, and the bottom wall is located outside the other side of the length direction of the movable contact piece, and the bottom wall of the other yoke clamp is connected to the surface of the third magnetic steel facing the movable contact, and the side walls are located outside both sides of the width direction of the movable contact piece, respectively, corresponding to the other movable contact. With this configuration of the present invention, the magnetic concentration of the U-shaped yoke clamp greatly improves the strength of the arc-extinguishing magnetic field and improves the arc-extinguishing effect.

[0080] 4. In the present invention, the movable contact is provided with a short-circuit-resistant structure having at least two magnetic rings consisting of an upper yoke and a lower armature. When a large fault current occurs in the movable contact, an attractive force is generated in the direction of the contact pressure to counteract the electromotive repulsive force generated by the fault current between the movable contact and the lead-out end of the static contact. When a fault current flows through the movable contact, a magnetic flux is generated in the magnetic circuit of at least two magnetic rings, and an attractive force is generated between the upper yoke and the lower armature of each magnetic circuit. This attractive force is in the direction of increasing the contact pressure to counteract the electromotive repulsive force between the contacts. By utilizing at least two magnetic rings, the fault current passing through the magnetic circuit of each magnetic ring is only Imax / n, making the magnetic circuit less likely to be saturated. The larger the passing current, the greater the increase in contact pressure and the greater the attractive force generated in the magnetic circuit.

[0081] 5. In the present invention, the short-circuit resistant structure includes a fixed upper yoke, a driven upper yoke and a lower armature, the fixed upper yoke is fixed to a predetermined fixed position on the first U-shaped bracket, is located on the movable contact piece, and corresponds to a position between the two movable contact pieces of the movable contact piece, the driven upper yoke is fixed to the inside of the bottom wall of the first U-shaped bracket and can move together with the first U-shaped bracket, the driven upper yoke is located on the movable contact piece, and corresponds to a position between the two movable contact pieces of the movable contact piece, and the lower armature is fixed to the bottom end surface of the movable contact piece, and corresponds to a position between the two movable contact pieces of the movable contact piece. Compared with the structure consisting of a driven upper yoke and a lower armature, it has stronger short-circuit resistance. In the case of a configuration consisting of a driven upper yoke and a lower armature, the upper yoke is fixed to the push rod with which it cooperates, and the push rod remains stationary by relying on the attractive force of the iron core, so when the short-circuit current becomes large to a certain extent, the electromagnetic attractive force generated between the short-circuit rings is also large, for example reaching 105 N, and at this time, the attractive force by the coil of the iron core is only 100 N, and the relay does not hold the iron core, the iron core is released, and the contacts are separated. In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke, and a lower armature uses part of the attractive force as a holding force for the iron core and the other part as a fixed yoke, and the driven upper yoke can offset part of the attractive force at the time of limit current interruption by magnetic short circuit, which is advantageous for current interruption, and although the load on the driven upper yoke affects the attraction, this is small and its thickness is small.

[0082] Hereinafter, the present invention will be described in detail with reference to the drawings and embodiments, but the DC relay capable of withstanding a short circuit current and extinguishing an arc according to the present invention is not limited to these embodiments.

[0083] Example 4 As shown in Figs. 22 to 25, the DC relay capable of withstanding a short circuit current and extinguishing an arc in this fourth embodiment includes two drawn-out ends 1 of static contacts, one straight sheet-shaped movable contact piece 2, one push rod assembly (not shown), and three magnetic steel pieces 81. The movable contact piece 2 is attached to the push rod assembly, and thus the operation of the movable contacts at both ends of the movable contact piece 2 and the static contacts at the bottom ends of the drawn-out ends 1 of the two static contacts is realized by the action of the push rod assembly. In this fourth embodiment, the movable contacts of the movable contact piece 2 are formed at both ends of the movable contact piece 2, and the static contacts of the drawn-out ends 1 of the static contacts are formed at the bottom ends of the drawn-out ends 1 of the static contacts. The first magnetic steel piece and the second magnetic steel piece of the three magnetic steel pieces 81 are respectively arranged on both sides of the width direction W of the movable contact piece 2, and are located at positions corresponding to the left contact, which is one of the movable contacts, and the magnetic poles of the surfaces of the first magnetic steel piece and the second magnetic steel piece (left side) facing the movable contact are the same. The third magnetic steel of the three magnetic steels 81 is disposed on the outside of one side (right side) in the longitudinal direction of the movable contact piece, and is located at a position corresponding to the right contact, which is the other movable contact. The pole face of the third magnetic steel 81 (right side) is nearly perpendicular to the pole faces of the first magnetic steel and the second magnetic steel 81 (left side), so that the Lorentz force generated in the extinguishing magnetic field formed by the three magnetic steels 81 of the movable contact piece 2 becomes nearly zero.

[0084] In this fourth embodiment, the magnetic pole of the surface of the third magnetic steel (right side) facing the movable contact is the same as the magnetic pole of the surfaces of the first magnetic steel and the second magnetic steel (left side) facing the movable contacts, so that the blow arc directions at the two movable contacts of the extinguishing magnetic field formed by the three magnetic steels 81 are directed in opposite outward directions.

[0085] In this fourth embodiment, the magnetic poles of the surfaces of the first magnetic steel and the second magnetic steel (left side) facing the movable contact (left side) are S poles, and the magnetic poles of the surfaces of the third magnetic steel (right side) facing the movable contact (right side) are also S poles.

[0086] In the DC relay capable of withstanding a short circuit current and extinguishing an arc in the fourth embodiment, three magnetic steels 81 are arranged at the contacts of the DC relay, and the first and second magnetic steels of the three magnetic steels 81 are arranged on the outside of both sides of the movable contact piece in the width direction, respectively, and are located at a position corresponding to one of the movable contacts (left side), and the magnetic poles of the surfaces of the first and second magnetic steels facing the movable contact are the same, and the third magnetic steel is arranged on the outside of one side of the movable contact piece 2 in the length direction, and is located at a position corresponding to the other movable contact (right side), and the pole face of the third magnetic steel (right side) is almost perpendicular to the pole faces of the first magnetic steel and the second magnetic steel (left side). With this configuration of the present invention, after realizing extinction by the magnetic steel, the Lorentz force generated in the extinguishing magnetic field formed by the three magnetic steels 81 of the movable contact piece becomes almost zero, and short circuit resistance against short circuit current can be improved.

[0087] In the DC relay capable of withstanding short circuit current and extinguishing arc in the fourth embodiment, the magnetic pole of the surface of the third magnetic steel (right side) facing the movable contact is the same as the magnetic pole of the surfaces of the first magnetic steel and the second magnetic steel (left side) facing the movable contact. With this configuration of the present invention, the arc blow directions of the arc extinguishing magnetic field formed by the three magnetic steels 81 at the two movable contacts are respectively directed in opposite outward directions, the product has no polarity requirement for the load wiring, the effect of forward arc extinguishing and reverse arc extinguishing is the same, and the use of the relay is convenient.

[0088] Example 5 As shown in Fig. 25 to Fig. 29, the difference between the DC relay capable of withstanding a short circuit current and extinguishing an arc in the fifth embodiment and the fourth embodiment is that the fifth embodiment includes two U-shaped yoke clamps 82, each of which includes two opposing side walls 822 and a bottom wall 821 connected to one end of the two side walls 822. Here, both side walls 822 of one yoke clamp 82 (left side) are connected to the surfaces facing the movable contacts of the first magnetic steel and the second magnetic steel (left side), respectively, and the bottom wall 821 is located outside the movable contact piece 2 in the length direction, and the bottom wall 821 of the other yoke clamp 82 (right side) is connected to the surface facing the movable contact of the third magnetic steel (right side), and the two side walls 822 are located on both sides in the width direction of the movable contact piece 2, respectively, and correspond to the other movable contact (right side). In this embodiment 5, when the surfaces of the three magnetic steels 81 facing the movable contacts are S poles, and when the lead-out end 1 of the left static contact is connected to the anode and the lead-out end 1 of the right static contact is connected to the cathode, the blow arc direction at the two movable contacts of the extinguishing magnetic field formed by the three magnetic steels 81 is as shown by the arrows in Fig. 28, and when the lead-out end 1 of the left static contact is connected to the cathode and the lead-out end 1 of the right static contact is connected to the anode, the blow arc direction at the two movable contacts of the extinguishing magnetic field formed by the three magnetic steels 81 is as shown by the arrows in Fig. 29. In this way, the positive and reverse electrodes show a centrally symmetrical distribution of the arc due to the magnetic blow extinguishing magnetic field.

[0089] In the DC relay of the fifth embodiment, two U-shaped yoke clamps 82 are added, and here, both side walls of one yoke clamp 82 (left side) are connected to the surfaces of the first magnetic steel and the second magnetic steel (left side) facing the movable contacts, respectively, and the bottom wall is located outside one side (left side) in the longitudinal direction of the movable contact piece 2, and the bottom wall of the other yoke clamp 82 (right side) is connected to the surface of the third magnetic steel 81 (right side) facing the movable contact, and both side walls are located on both sides in the width direction of the movable contact piece 2 and correspond to the other movable contact (right side). With this configuration of the present invention, the magnetic concentration of the U-shaped yoke clamp 82 greatly improves the strength of the arc-extinguishing magnetic field, improving the arc-extinguishing effect.

[0090] Example 6 30 to 37, in the DC relay capable of withstanding a short circuit current and extinguishing an arc in this embodiment 6, the push rod assembly includes a first U-shaped bracket 31, a spring 32, a spring seat 33 and a push rod 34, and an upper portion of the push rod 34 is fixed to the spring seat 33. The first U-shaped bracket 31 is in an inverted U shape and includes two opposing side walls 310 and a bottom wall 311 connected to ends of the two side walls 310, the bottom wall 311 of the first U-shaped bracket 31 is fixed to the spring seat 33, and the movable contact piece 2 is attached to the first U-shaped bracket 31 via the spring 32. The difference between Example 6 and Example 5 is that the DC relay further includes a short-circuit resistant structure having at least two magnetic rings each consisting of an upper yoke and a lower armature. When a large fault current occurs in the movable contact, an attractive force is generated in the direction of the contact pressure to counteract the electromotive repulsive force generated by the fault current between the movable contact and the lead-out end of the static contact.

[0091] In this sixth embodiment, the short-circuit resistant structure includes an upper yoke 4 and a lower armature 6. The upper yoke 4 is fixed to the inside of the bottom wall 311 of the first U-shaped bracket 31 and is located above the movable contact piece 2, corresponding to a position between the two movable contacts of the movable contact piece 2, and the lower armature 6 is fixed to the bottom end surface of the movable contact piece 2, corresponding to a position between the two movable contacts of the movable contact piece 2. The upper yoke 4 and the lower armature 6 are distributed along the width direction of the movable contact piece 2, and on both sides of the width direction of the movable contact piece 2, the upper yoke 4 and the lower armature 6 are adjacent to or in contact with each other, and at least one through hole 211 is further provided in the movable contact piece 2 at said position, so that the upper yoke 4 and the lower armature 6 are adjacent to or in contact with each other through the through hole 211, and at least two magnetic rings are formed by the upper yoke 4 and the lower armature 6 in the width direction of the movable contact piece, and by utilizing the increased magnetic pole surface at the position of the corresponding through hole in each magnetic ring, when a large fault current occurs in the movable contact piece 2, an attractive force is generated in the direction of the contact pressure to counteract the electromotive repulsive force generated by the fault current between the movable contact piece and the lead-out end of the static contact.

[0092] In this sixth embodiment, the upper yoke 4 includes two straight-shaped upper yokes 41, the lower armature 6 includes two U-shaped lower armatures 60, and the two U-shaped lower armatures 60 are fitted to the two straight-shaped upper yokes 41 to form two independent magnetic rings, each side wall of one of the two U-shaped lower armatures 60 is attached to a corresponding side wall in the width direction of the movable contact piece 2, each of the other side walls of the two U-shaped lower armatures 60 passes through a single through hole 211 of the movable contact piece, and there is a gap between each other side wall of the two U-shaped lower armatures 60.

[0093] In the sixth embodiment, the movable contact piece 2 is provided with enlarged portions 212 on both sides in the width direction at a position corresponding to the through hole 211, thereby increasing the current carrying capacity of the movable contact piece 2.

[0094] In this sixth embodiment, the U-shaped lower armature 60 is fixed to the bottom end surface of the movable contact 2, so that the upper end of the spring 32 abuts against the bottom end of the U-shaped lower armature 60, and a protrusion 601 is further provided at the bottom end of the U-shaped lower armature 60 to limit the position of the spring 32.

[0095] In the present invention, two magnetic rings, i.e., two magnetic circuits, are formed in the movable contact 2, and two U-shaped lower armatures 60 have a configuration of four side wall upper surfaces and a one-shaped upper yoke 41, i.e., two U-shaped lower armatures 60 have four magnetic pole faces, and compared with one magnetic circuit (only two magnetic pole faces), when the configuration of the lower armatures 60 is maintained, two magnetic pole faces (two magnetic pole faces at the through hole position of the movable contact are added) are increased, which improves the magnetic efficiency and increases the attractive force. When a large fault current occurs in the movable contact 2, an attractive force is generated in the two independent magnetic circuits, which counteracts the electric repulsive force generated by the fault current between the movable contact and the lead end of the static contact, and the short-circuit current (fault current) resistance function of the present invention can be greatly improved.

[0096] Due to the constraints of the configuration conditions, the magnetic circuit does not have a cross-sectional area with sufficient magnetic permeability, and in the case of a fault current, one magnetic circuit is very likely to saturate, and the attractive force cannot be increased. The two magnetic circuits in the embodiment of the present invention divide the current flow direction into two cross-sectional areas, each cross-sectional area is a shunt current, and the shunt current is basically less than half of the fault current, so the magnetic circuit is not magnetically saturated, the magnetic flux increases, and the generated attractive force also increases, so that the two magnetic circuits of the present invention increase the short-circuit resistance current by a factor of 1 compared with the single magnetic circuit of the prior art. According to the level of the system fault current and the cross-sectional area of ​​the magnetic conduction, the magnetic circuits may be arranged in N numbers.

[0097] When the push rod assembly does not move upward, the upper surface of the movable contact piece 2 abuts against the bottom surface of the straight-shaped upper yoke 41 under the action of the spring 32. When the push rod assembly moves to a suitable position, the movable contacts at both ends of the movable contact piece 2 respectively contact the bottom ends of the drawn-out ends 1 of the two static contacts. Then, the push rod assembly continues to move upward, and the straight-shaped upper yoke 41 moves upward together with the push rod assembly. Since the movable contact piece 2 has already contacted the bottom ends of the drawn-out ends 1 of the two static contacts, the movable contact piece 2 cannot continue to move upward, resulting in overtravel of the contacts. The spring 32 provides contact pressure, and a certain gap is formed between the bottom end of the straight-shaped upper yoke 41 and the upper surface of the movable contact piece 2. Thus, a magnetic gap is formed between the bottom surface of the straight-shaped upper yoke 41 and the upper surface of the U-shaped lower armature 60.

[0098] In the DC relay capable of withstanding short-circuit current and extinguishing arc in the sixth embodiment, the movable contact 2 is arranged with a short-circuit resistant structure having at least two magnetic rings consisting of an upper yoke 4 and a lower armature 6. When a large fault current occurs in the movable contact 2, an attractive force in the direction of the contact pressure is generated, which counteracts the electromotive repulsive force generated by the fault current between the movable contact and the lead-out end of the static contact. When a fault current flows through the movable contact, a magnetic flux is generated in the magnetic circuit of at least two magnetic rings, and an attractive force is generated between the upper yoke and the lower armature of each magnetic circuit. This attractive force is in the direction of increasing the contact pressure, which counteracts the electromotive repulsive force between the contacts. By utilizing at least two magnetic rings, the fault current passing through the magnetic circuit of each magnetic ring is only Imax / n, which makes the magnetic circuit less likely to be saturated. The larger the passing current, the greater the increase in contact pressure and the greater the attractive force generated in the magnetic circuit.

[0099] Example 7 As shown in FIGS. 1 to 21, the DC relay capable of withstanding a short-circuit current and extinguishing an arc in the seventh embodiment differs from the fifth embodiment in the short-circuit resistant structure attached to the movable contact piece 2.

[0100] In this embodiment 7, the short-circuit resistant structure includes a fixed upper yoke 4, a driven upper yoke 5 and a lower armature 6. The fixed upper yoke 4 is fixed at a predetermined fixed position on the first U-shaped bracket, and is located on the movable contact 2 and corresponds to the position between the two movable contacts of the movable contact 2; the driven upper yoke 5 is fixed to the inside of the bottom wall of the first U-shaped bracket 31 and can move together with the first U-shaped bracket 31; the driven upper yoke 5 is located on the movable contact 2 and corresponds to the position between the two movable contacts of the movable contact 2; and the lower armature 6 is fixed to the bottom end surface of the movable contact 2 and corresponds to the position between the two movable contacts of the movable contact 2. The fixed upper yoke 4, the driven upper yoke 5 and the lower armature 6 are distributed along the width direction of the movable contact 2 respectively. On both sides of the width of the movable contact piece 2, the lower armature 6 is close to or in contact with the fixed upper yoke 4 and the driven upper yoke 5, respectively, and the lower armature 6, the fixed upper yoke 4, and the driven upper yoke 5 form a magnetic ring in the width direction of the movable contact piece 2, with two overlapping parts.When a large fault current occurs in the movable contact piece 2, an attractive force is generated in the direction of the contact pressure, which counters the electromotive repulsive force generated by the fault current between the movable contact piece and the pull-out end of the static contact.

[0101] In this embodiment 7, the predetermined fixing location is an inner location of the bottom wall of an inverted U-shaped second U-shaped bracket 72 fixed to a relay-like yoke plate 71, and the push rod 34 of the push rod assembly passes through the yoke plate 71 and is fixed to a movable iron core that is a part of the magnetic circuit of the relay.

[0102] In this seventh embodiment, the fixed upper yoke 4 and the driven upper yoke 5 are each shaped like a straight line, the lower armature 6 is shaped like a U, and the bottom wall 311 of the first U-shaped bracket 31 is provided with through holes 312 that allow both side walls of the lower armature 6 to protrude upward and contact or come close to the upper fixed upper yoke 4, and a magnetic ring is formed in which the two parts of the U-shaped lower armature 6, the straight-shaped fixed upper yoke 4, and the driven upper yoke 5 overlap each other.

[0103] In this embodiment 7, steps 62 are further provided on both side walls 65 of the lower armature 6, and convex portions 63 are formed at the higher portions of the steps of both side walls 65 of the lower armature 6, and the convex portions 63 pass through the through holes 312 in the bottom wall 311 of the first U-shaped bracket 31 and come into contact with or close to the fixed upper yoke 4 to form one magnetic ring, and the steps 62 on both side walls of the lower armature 6 come into contact with or close to the driven upper yoke 5 to form another magnetic ring, and the two magnetic rings overlap the lower armature 6.

[0104] In this seventh embodiment, a recess 51 for receiving the protrusion 63 of the lower armature is provided on each end of the driven upper yoke 5, and a boss 52 for engaging with a through hole in the bottom wall of the first U-shaped bracket of the push rod assembly is provided on the inside of the recess 51.

[0105] When the push rod assembly does not move upward, the upper surface of the movable contact piece 2 abuts against the bottom surface of the driven upper yoke 5 under the action of the spring 32. When the push rod assembly moves to a suitable position, the two movable contacts at both ends of the movable contact piece 2 respectively contact the bottom ends of the drawn-out ends 1 of the two static contacts. At this time, the steps 62 on both side walls of the lower armature 6 respectively contact the driven upper yoke 5, and the protrusions 63 on both side walls of the lower armature 6 respectively contact or are close to the fixed upper yoke 4. Then, the push rod assembly continues to move upward, and the driven upper yoke 5 moves upward together with the push rod assembly. Since the movable contact piece 2 has already contacted the bottom ends of the drawn-out ends 1 of the two static contacts, the movable contact piece 2 cannot continue to move upward, resulting in overtravel of the contacts. The spring 32 provides contact pressure, and a certain gap is formed between the bottom end of the driven upper yoke 5 and the upper surface of the movable contact piece 2. This configuration of the present invention allows the fixed upper yoke 4 to be stationary to increase the attractive force against the lower armature 6, for example by increasing the thickness of the fixed upper yoke 4 to increase the magnetic attractive force, or by utilizing the driven upper yoke 5 to magnetically counteract a portion of the attractive force when the limiting current is interrupted, making it easier to interrupt the current.

[0106] In the seventh embodiment of the present invention, a fixed upper yoke 4 is fixed at a fixed position on the first U-shaped bracket above the position between the two movable contacts of the movable contact, a driven upper yoke 5 is fixed to the inside of the bottom wall of the first U-shaped bracket above the position between the two movable contacts of the movable contact and moves together with the first U-shaped bracket, and a lower armature 6 is fixed to the bottom end surface of the movable contact at the position, and has stronger short-circuit resistance than a configuration consisting of a driven upper yoke and a lower armature. In the case of a configuration consisting of a driven upper yoke and a lower armature, the upper yoke is fixed to the push rod with which it cooperates, and the push rod remains stationary by relying on the attractive force of the iron core, so that when the short-circuit current becomes large to a certain extent, the electromagnetic attractive force generated between the short-circuit rings is also large, for example reaching 105N, and at this time, the attractive force by the coil of the iron core is only 100N, and the relay does not hold the iron core, the iron core is released, and the contacts are separated. In the present invention, the configuration consisting of a fixed upper yoke, a driven upper yoke, and a lower armature uses part of the attractive force as a holding force for the iron core, and the other part is assigned to the fixed yoke, and the driven upper yoke can offset part of the attractive force when the limiting current is interrupted by magnetic short circuit, which is advantageous for current interruption, the effect of turning on the load of the driven upper yoke on the attraction is small, and its thickness is small.

[0107] It should be noted that the present invention is not limited in its application to the detailed construction and arrangement of the components shown in this specification. The present invention is capable of other embodiments and can be realized and carried out in various ways. The above-mentioned variations and modifications are within the scope of the present invention. It is understood that the invention disclosed and limited by this specification extends to all alternative combinations of two or more individual features mentioned or apparent in the text and / or the accompanying drawings. All of these different combinations constitute multiple alternative aspects of the invention. The embodiments described herein are illustrative of the best ways known for carrying out the invention and will enable those skilled in the art to utilize the invention.

Claims

1. A DC relay with short circuit current resistance and arc extinction, comprising two static contact lead ends, one straight sheet-shaped movable contact piece, one push rod assembly and three magnetic steels, The movable contact piece is attached to a push rod assembly, whereby the action of the push rod assembly realizes the operation of the movable contacts at both ends of the movable contact piece and the static contacts at the bottom ends of the drawn-out ends of the two static contacts, the first magnetic steel and the second magnetic steel of the three magnetic steels are respectively arranged on both sides in the width direction of the movable contact piece, the first magnetic steel and the second magnetic steel are respectively spaced apart from each other between the movable contact pieces, the first magnetic steel and the second magnetic steel are adjacent to one of the two movable contacts of the movable contact piece, the magnetic poles of the surfaces of the first and second magnetic steels facing the adjacent movable contact are the same, a third magnetic steel of the three magnetic steels is arranged on one side of the movable contact piece in the longitudinal direction, a gap is provided between the third magnetic steel and the movable contact piece, the third magnetic steel is adjacent to the other of the two movable contacts of the movable contact piece, and the pole faces of the third magnetic steel are approximately perpendicular to the pole faces of the first and second magnetic steels, whereby the Lorentz force generated in the extinguishing magnetic field formed by the movable contact piece and the three magnetic steels is approximately zero; The DC relay is provided with a short-circuit-resistant structure, which includes an upper yoke and a lower armature, in which the upper yoke is located on the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, and the lower armature is fixed to a bottom end surface of the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, and when a large fault current occurs in the movable contact piece, an attractive force is generated in the pressure direction of the contacts, which counteracts the electromotive repulsive force generated by the fault current between the movable contact piece and the drawn-out end of the static contact. A DC relay characterized by:

2. Since the magnetic pole of the surface of the third magnetic steel facing the movable contact is the same as the magnetic pole of the surfaces of the first magnetic steel and the second magnetic steel facing the movable contact, the blow arc directions at the two movable contacts of the arc-extinguishing magnetic field formed by the three magnetic steels are directed in opposite outward directions.

2. A DC relay according to claim 1.

3. The DC relay further includes two U-shaped yoke clamps, each of which includes two opposing side walls and a bottom wall connected to one end of the two side walls, wherein the two side walls of one yoke clamp are connected to the surfaces of the first magnetic steel and the second magnetic steel facing away from the movable contact, respectively, and the bottom wall is located on one side of the movable contact piece in the length direction, and the bottom wall of the other yoke clamp is connected to the surface of the third magnetic steel facing away from the movable contact, and the two side walls are located on the outer sides of both sides in the width direction of the movable contact piece, respectively.

2. A DC relay according to claim 1.

4. The push rod assembly includes a first U-shaped bracket having an inverted U shape, a spring, a spring seat, and a push rod, an upper portion of the push rod is fixed to the spring seat, the first U-shaped bracket includes two opposing side walls and a bottom wall connected to one ends of the two side walls, the bottom wall of the first U-shaped bracket is fixed to the spring seat, and the movable contact piece is attached to the first U-shaped bracket by the spring.

4. A DC relay according to claim 1, wherein the first and second terminals are electrically connected to each other.

5. The upper yoke is fixed to the inside of the bottom wall of the first U-shaped bracket, the upper yoke and the lower armature are distributed along the width direction of the movable contact piece, and at least one through hole is provided in the movable contact piece on both sides of the width direction of the movable contact piece, so that the upper yoke and the lower armature pass through the through hole and approach or contact each other, and at least two magnetic rings are formed by the upper yoke and the lower armature in the width direction of the movable contact piece, and by utilizing the increased magnetic pole surface at the position of the corresponding through hole of each of the magnetic rings, when a large fault current occurs in the movable contact piece, an attractive force is generated in the direction of the contact pressure to counteract the electromotive repulsive force generated by the fault current between the movable contact piece and the pull-out end of the static contact.

5. A DC relay according to claim 4.

6. The upper yoke is a single straight-shaped upper yoke, the lower armature is a plurality of U-shaped lower armatures, and a plurality of independent magnetic rings are formed by the plurality of U-shaped lower armatures and corresponding parts of the straight-shaped upper yoke, and two U-shaped lower armatures of two adjacent magnetic rings are not in contact with each other.

6. A DC relay according to claim 5.

7. The upper yoke is a plurality of linear upper yokes, and the lower armatures are a corresponding number of U-shaped lower armatures, and a plurality of independent magnetic rings are formed by the U-shaped lower armatures and the corresponding linear upper yokes, and two U-shaped lower armatures of two adjacent magnetic rings are not in contact with each other.

6. A DC relay according to claim 5.

8. A plurality of U-shaped lower armatures, the number of which corresponds to the plurality of linear upper yokes, are arranged in a linear fashion along the width direction of the movable contact piece.

8. A DC relay as claimed in claim 7.

9. A plurality of U-shaped lower armatures corresponding to the plurality of line-shaped upper yokes are arranged at intervals along the width direction of the movable contact piece.

8. A DC relay as claimed in claim 7.

10. The upper yoke is one or two straight-shaped upper yokes, the lower armature is two U-shaped lower armatures, and the two U-shaped lower armatures are matched with the corresponding parts of one straight-shaped upper yoke or two straight-shaped upper yokes to form two independent magnetic rings, each side wall of the two U-shaped lower armatures is attached to the corresponding side wall in the width direction of the movable contact piece, the other side walls of the two U-shaped lower armatures pass through the same through hole or through holes at two different positions of the movable contact piece, and there is a gap between the other side walls of the two U-shaped lower armatures.

6. A DC relay according to claim 5.

11. The short-circuit resistant structure includes a fixed upper yoke, a driven upper yoke and a lower armature, the fixed upper yoke is fixed to a predetermined fixed position on a first U-shaped bracket, is located on the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, the driven upper yoke is fixed to the inside of a bottom wall of the first U-shaped bracket and can move together with the first U-shaped bracket, the driven upper yoke is located on the movable contact piece and corresponds to a position between two movable contacts of the movable contact piece, and the lower armature is fixed to a bottom end surface of the movable contact piece; The fixed upper yoke, the driven upper yoke and the lower armature are distributed along the width direction of the movable contact piece, corresponding to the position between the two movable contacts of the movable contact piece, and on both sides of the width direction of the movable contact piece, the lower armature is close to or in contact with the fixed upper yoke and the driven upper yoke, and two magnetic rings are formed in the width direction of the movable contact piece by the lower armature, the fixed upper yoke and the driven upper yoke, and when a large fault current occurs in the movable contact piece, an attractive force is generated in the direction of the contact pressure, which counters the electromotive repulsive force generated by the fault current between the movable contact piece and the lead-out end of the static contact.

5. A DC relay according to claim 4.

12. The predetermined fixing location is the inner bottom wall of the relay case.

12. A DC relay as claimed in claim 11.

13. The predetermined fixing location is the inside of the bottom wall of a second U-shaped bracket of an inverted U-shape fixed to the yoke plate of the relay.

12. A DC relay as claimed in claim 11.

14. The fixed upper yoke and the driven upper yoke are each shaped like a straight line, the lower armature is shaped like a U and includes two opposing side walls and a bottom wall connected to one end of the two side walls, and the bottom wall of the first U-shaped bracket is provided with through holes through which both side walls of the lower armature protrude upward and contact or approach the upper fixed upper yoke, and a magnetic ring is formed with two overlapping portions of the lower armature, the fixed upper yoke, and the driven upper yoke, which are shaped like a straight line.

12. A DC relay as claimed in claim 11.

15. A step is further provided on both side walls of the lower armature, and a convex portion is formed at a high portion of the step, and the convex portion passes through a through hole in the bottom wall of the first U-shaped bracket and contacts or is adjacent to the fixed upper yoke to form one magnetic ring, and the steps on both side walls of the lower armature contact or are adjacent to the driven upper yoke, respectively, to form another magnetic ring, and the two magnetic rings overlap the lower armature.

15. A DC relay as claimed in claim 14.

16. The driven upper yoke is provided at both ends with recesses for receiving the protrusions of the lower armature, and bosses are provided on the inside of the recesses to engage with through holes in the bottom wall of the first U-shaped bracket.

16. A DC relay as claimed in claim 15.

Images