An overcurrent protection relay

Abstract

The application provides an overcurrent protection relay and relates to the field of relays. The overcurrent protection relay comprises a relay main body, an iron core and a lock catch connecting rod installed in the relay main body, a supporting rod and an armature installed in the relay main body, and connecting pieces installed between the supporting rod and the armature, and elastic sheets are installed between the fixed parts of the two connecting pieces; the gravity of the armature and the elastic sheets form an included angle between the fixed part and the movable part of the connecting piece. The overcurrent protection relay forms a surface contact between the armature and the iron core, improves the adsorption efficiency of the iron core, shortens the response time, and adopts eccentric setting for the convex part, and the radius of the convex part increases along the rotation direction; the eccentric setting makes the length of the force arm of the convex part increase with the increase of the angle when the convex part rotates, and the radius of the convex part increases, so that the pushing force on the lock catch connecting rod is continuously amplified during the rotation process; even if the lubricating grease carbonizes and the friction problem exists at the fulcrum, the lock catch connecting rod can still be quickly pushed, the response time is further shortened, and the movement lag of the armature is prevented.

Description

Technical Field

[0001] This invention relates to the field of relays, specifically to an overcurrent protection relay. Background Technology

[0002] An overcurrent protection relay is a relay device that automatically detects and triggers protective action when an abnormal situation occurs in a circuit or electrical equipment, exceeding its rated current. By monitoring the current magnitude, it quickly cuts off the circuit or issues an alarm signal when the current exceeds a preset threshold to prevent equipment damage due to overcurrent. A relay current transformer is used to proportionally convert large currents in the main circuit into smaller currents for relay detection. It is typically wrapped around the conductors of the main circuit and operates on the principle of electromagnetic induction. The relay coil is connected to the current transformer, generating a magnetic field through the current. The number of turns and wire diameter of the coil are designed according to the relay's rated current and sensitivity. There is a certain air gap between the relay's iron core and armature. When current flows through the coil, the iron core generates a magnetic field, attracting the armature. The relay's return spring provides a reaction force to balance the electromagnetic attraction. When the electromagnetic attraction exceeds the force of the return spring... When the relay is activated, the armature actuates. When the armature actuates, the moving contact closes or opens with the stationary contact, thereby controlling the on / off state of the circuit. The contact system usually has two types: normally open contacts and normally closed contacts. Normally open contacts are open when the relay is not activated and closed when it is activated, while normally closed contacts are the opposite. When the overcurrent protection is activated, the trip unit and the lever mechanism are linked. After the trip unit, such as an electromagnetic trip unit or a thermal trip unit, is triggered, the force is transmitted to the driven end through the lever. The driven end pushes the trip half shaft or the trip latch, causing the relay to open. After the relay is de-energized, the coil remains energized. At this time, the iron core and the armature are in the attracted state, but the contacts have cut off the main circuit, not the control circuit where the coil is located. The coil is usually connected in series in the control circuit, while the contacts are connected in series in the main circuit. When the main circuit is overcurrent, the contacts disconnect the main circuit, but the coil in the control circuit is still energized, maintaining the attracted state of the armature until manual reset or manual disconnection of the control circuit power supply after the fault is cleared.

[0003] When a traditional relay operates under overcurrent protection, the iron core attracts the armature, which drives the lever to move. The fulcrum, driving end, and driven end of the lever form a mechanical transmission structure. The driven end is used to push the tripping and locking mechanism, such as the tripping half-shaft or locking linkage, to release the mechanical lock on the moving contact. This allows the moving contact to quickly disconnect under the drive of the tripping spring, thus achieving circuit disconnection protection.

[0004] According to actual test data, during long-term operation of the relay, carbonization of the grease at the fulcrum will extend the time for the iron core to attract the armature from 12ms to 45ms. In addition, environmental dust or copper shavings generated during breakage will enter the fulcrum gap and cause foreign matter accumulation. Oxidation and rust on the metal surface, if caused by humidity or corrosive gases, will further increase frictional resistance. As the axis of lever rotation, the increased friction at the fulcrum will directly hinder the lever transmission, resulting in a longer attraction time and a delayed armature movement. Ultimately, this will delay the action of the locking linkage, causing overcurrent protection to be delayed or fail to operate. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an overcurrent protection relay that solves the problem of increased fulcrum friction hindering lever transmission, leading to prolonged adsorption time and delayed armature movement.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: an overcurrent protection relay, including a relay body and an iron core and a locking rod installed in the relay body, and also including a support rod and an armature installed in the relay body, with a connecting member installed between the two. An elastic sheet is installed between the fixed parts of the two connecting members. The gravity of the armature, together with the elastic sheet, causes the fixed part and the movable part of the connecting member to form an angle, and limits the movement trajectory of the armature to move in a direction perpendicular to the end face of the iron core.

[0007] One of the connectors has a "6"-shaped protrusion at the end near the support rod. The radius of the protrusion increases sequentially from the starting point to the ending point along the direction of rotation, and the protrusion of the connector contacts the locking link.

[0008] Preferably, the connector includes a fixed fastener and a sling, the fastener being mounted on the support rod via a cylinder, and the sling being mounted on the armature via a cylinder.

[0009] Preferably, there are multiple fasteners and slings, and the multiple slings are distributed in a matrix.

[0010] Preferably, the elastic sheet is initially bent, and both ends of the elastic sheet are rotatably connected to the adjacent fixing members via connecting rods.

[0011] Preferably, there is a gap between the armature and the iron core in the initial state, and when the iron core attracts the armature, the two form a surface contact.

[0012] Preferably, the protrusion of the connector is provided with a groove that is conjugate to the outer periphery of the protrusion, and the locking link is located in the groove and contacts the groove in the protrusion.

[0013] Preferably, the armature is collinear with the central axis of the iron core.

[0014] Preferably, the protrusion of the connector is eccentrically positioned relative to the support rod, with the support rod positioned closer to the end of the protrusion with a smaller radius.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the armature and the iron core are collinear, and the vertical movement trajectory is limited by the elastic sheet and gravity, so that the armature and the iron core form a surface contact, which improves the iron core adsorption efficiency and shortens the response time. The protrusion is eccentrically set, and the radius increases along the rotation direction. The eccentric setting makes the lever arm of the protrusion longer as the angle increases when the protrusion rotates. With the increase of the radius of the protrusion, the thrust on the locking link is continuously amplified during the rotation. Even if there are problems such as grease carbonization and friction at the fulcrum, the locking link can still be pushed quickly, which further shortens the response time and prevents the armature movement from lagging. The direct contact between the protrusion and the locking link eliminates the energy loss at the moment of collision, reduces the kinetic energy loss of the transmission link, and improves the transmission efficiency. At the same time, the contact transmission is uniformly stressed, avoiding plastic deformation caused by frequent collisions and uneven stress, ensuring the accuracy and stability of long-term use and improving the service life. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the relay body of the present invention;

[0017] Figure 2 This is a schematic diagram of the internal structure of the overall frame of the relay body of the present invention;

[0018] Figure 3 This is a top view of part of the structure of the present invention;

[0019] Figure 4 This is a front view of the entire core of the present invention after the armature is attracted;

[0020] Figure 5 This is a front view of the connector of the present invention;

[0021] Figure 6 This is a cross-sectional view of the front view of the connector of the present invention;

[0022] Figure 7 This is a partial schematic diagram of the iron core before the armature is attracted to the iron core in this invention;

[0023] Figure 8 This is a partial schematic diagram of the iron core after the armature is attracted to the iron core of the present invention;

[0024] Figure 9 This is a top view of the connector of the present invention;

[0025] Figure 10 This is a schematic diagram of the structure of the connector and protrusion of the present invention.

[0026] Among them, 1. Relay body; 101. Iron core; 102. Locking rod; 103. Armature; 104. Support rod; 3. Connector; 301. Fixing part; 302. Lifting strap; 303. Protrusion; 4. Elastic sheet; 5. Groove. Detailed Implementation

[0027] like Figures 1-10 As shown, an overcurrent protection relay includes a relay body 1, an iron core 101 and a locking rod 102 installed inside the relay body 1, a support rod 104 and an armature 103 installed inside the relay body 1, and a connector 3 installed between them. The connector 3 includes a fixing part 301 and a sling 302 that are fixed together. The fixing part 301 is installed on the support rod 104 through a cylinder, and the sling 302 is installed on the armature 103 through a cylinder. The fixing part 301 serves as the fixed part of the connector 3, and the sling 302 serves as the movable part of the connector 3. Both the fixing part 301 and the sling 302 are fixed to the cylinders that are close to each other. Several fixing parts 301 and several slings 302 are provided, and the several slings 302 are distributed in a matrix, which makes the armature 103 more stable. The protrusion 303 of the connector 3 The protrusion 303 has a groove 5 that is conjugate to its outer periphery. The radius of the groove 5 also increases sequentially along the rotation direction. The locking link 102 is located in the groove 5 and contacts the groove 5 in the protrusion 303. The armature 103 is collinear with the central axis of the iron core 101. An elastic plate 4 is installed between the fixed parts of the two connecting parts 3. The elastic plate 4 is initially bent. Both ends of the elastic plate 4 are rotatably connected to the fixed parts 301 that are close to it through a connecting rod. The gravity of the armature 103, together with the elastic plate 4, makes the fixed part and the movable part of the connecting part 3 form an angle, and limits the movement trajectory of the armature 103 to move in a direction perpendicular to the end face of the iron core 101. In the initial state, there is a gap between the armature 103 and the iron core 101. When the iron core 101 attracts the armature 103, the two form a surface contact.

[0028] One of the connectors 3 has a "6"-shaped protrusion 303 at one end near the support rod 104. The radius of the protrusion increases sequentially from the starting point to the ending point along the rotation direction. The protrusion 303 of the connector 3 is in contact with the locking link 102. The radius of the protrusion 303 increases at a constant rate. When the iron core 101 attracts the armature 103, the protrusion 303 rotates around the support rod 104 as the axis. The spiral arc surface pushes the locking link 102 to move linearly, releasing the lock on the moving contact in the relay body 1. The protrusion 303 of the connector 3 is eccentrically set with the support rod 104, and the support rod 104 is closer to the end with the smaller radius of the protrusion 303.

[0029] During use, if an overcurrent occurs in the circuit, the current will flow through the coil on the iron core 101. As the current flows, a magnetic field is immediately generated around the coil. Due to the high magnetic permeability of the iron core 101, the magnetic field is concentrated and amplified, thus enhancing the magnetism of the iron core 101. The enhanced magnetic field forms a magnetic field loop between the iron core 101 and the armature 103. The armature 103 is also made of magnetically permeable material. Under the influence of the magnetic field, the armature 103 is magnetized, becoming a temporary magnet. Based on the fundamental properties of magnets, unlike magnetic poles attract each other. The magnetic force between the iron core 101 and the armature 103 overcomes the elastic force of the elastic plate 4 and the gravity of the armature 103, generating an attractive force pointing towards the iron core 101. Since the central axes of the armature 103 and the iron core 101 are collinear, and the two ends of the connector 3 are connected to the armature 103 and the support rod 104 respectively, the gravity of the elastic plate 4 and the armature 103 causes the two ends of the connector 3 to form a fixed angle. When the armature 103 moves, this angle acts like a track, allowing the armature 103 to move perpendicularly to its end face, so that the magnetic force can be evenly applied to the armature 103, ensuring the stability of the force on the armature 103 and avoiding the influence of magnetic force. The uneven magnetic field distribution and attraction loss caused by the offset of armature 103 allow the iron core 101 to attract armature 103 with higher efficiency. As the current continues to increase, the magnetic field strength continuously increases. When the magnetic force is sufficient to overcome the elastic force of the elastic sheet 4, armature 103 begins to move towards the iron core 101 in a direction perpendicular to the end face of the iron core 101. The air gap between the two gradually decreases until it comes into close contact with the iron core 101, forming a surface contact state. At the surface contact, the contact area between the iron core 101 and armature 103 is the largest, which can maximize the effect of electromagnetic attraction and ensure that armature 103 is reliably attracted, which is beneficial to subsequent unlocking and disconnection actions.

[0030] Next, as Figure 7 and Figure 8As shown, when the iron core 101 attracts the armature 103, the armature 103 will drive the connected connector 3 to move. One end of the connector 3 is sleeved on the support rod 104 through the fixing member 301. The connector 3 rotates around the support rod 104. One end of the connector 3 near the support rod 104 has a "6"-shaped protrusion 303. At this time, the protrusion 303, as the end of the connector 3 near the support rod 104, will start to rotate around the support rod 104 as the axis. When the protrusion 303 rotates around the support rod 104, its radius increases sequentially from the starting point to the ending point along the direction of rotation, and the protrusion 303 of the connector 3 contacts the bottom end of the locking link 102. The groove 5 of the starting part 303 continuously pushes the locking link 102 to move linearly. The locking link 102, which was originally locked to the moving contact, will be unlocked after being pushed. The moving contact will quickly disconnect the circuit under the elastic force of the opening spring, realizing overcurrent protection. It should be noted that in the whole process, the rotation of the protrusion 303 is like the handle of a switch. The electromagnetic force pulling the armature 103 is the power to turn the handle. The eccentric setting of the protrusion 303 and the support rod 104 and the radius of the protrusion 303 increase in sequence, so that the pushing force of the protrusion 303 on the locking link 102 gradually increases. In this process, the two work together to overcome the fulcrum friction, ensuring smooth rotation, timely protection, and more effortless and efficient operation.

[0031] Next, it should be noted that the protrusion 303 and the support rod 104 are eccentrically positioned, with the support rod 104 closer to the smaller radius end of the protrusion. This causes the center of rotation of the protrusion to be not at the exact center of the protrusion 303, but rather offset towards the smaller radius side. Like using an off-center key to open a door, this generates greater twisting force when rotating. When the protrusion rotates around the support rod 104, the distance from the support rod 104 to the center of the protrusion forms a lever arm. As the protrusion rotates, the lever arm gradually lengthens, thus amplifying the thrust on the locking link 102 and easily overcoming fulcrum friction. The radius of the protrusion 303 gradually increases from the starting point to the ending point, resembling the pattern of a snail shell. When the protrusion begins to rotate, the smaller radius end contacts the locking link 102 first. As the rotation angle increases, the radius of the protrusion gradually increases... The lever mechanism in this device uses increasingly longer levers to push the locking link 102, resulting in a greater and greater pushing force from the protrusion 303 on the locking link 102 during rotation. Even if there is friction at the fulcrum, such as carbonized grease, the increasing pushing force from the protrusion ensures that the locking link 102 is pushed. Traditional relays use lever mechanisms, which collide with the locking link 102 through swinging motion. The impact force at the moment of collision is large, leading to energy loss. Long-term frequent collisions and uneven force distribution, coupled with fulcrum friction and vibration, make the lever prone to plastic deformation, reducing transmission accuracy and affecting relay performance and service life. In contrast, the protrusion 303 of this device contacts the locking link 102, eliminating collisions during transmission, reducing energy loss, and ensuring uniform force distribution through contact transmission, reducing the probability of deformation and extending service life.

[0032] Finally, after the locking linkage 102 completes its movement, the locking of the moving contact in the relay body 1 is released. The moving contact quickly disconnects the circuit under the drive of the tripping spring, realizing the overcurrent protection function. After the circuit fault is cleared and the current returns to normal, the relay needs to be reset. After the power is cut off, the magnetic field of the iron core 101 disappears, and the restoring force of the elastic sheet 4 and the gravity of the armature 103 work together to make the connecting piece 3 rotate in the opposite direction and return to the initial state, waiting for the next operation.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An overcurrent protection relay, comprising a relay body (1) and an iron core (101) and a locking linkage (102) installed within the relay body (1), characterized in that: It also includes a support rod (104) and an armature (103) installed in the relay body (1), and a connector (3) is installed between the two. An elastic plate (4) is installed between the fixed parts of the two connectors (3). The gravity of the armature (103) and the elastic plate (4) make the fixed part and the movable part of the connector (3) form an angle, and limit the movement trajectory of the armature (103) to move in a direction perpendicular to the end face of the iron core (101). One of the connectors (3) has a "6"-shaped protrusion (303) at one end near the support rod (104), the radius of which increases sequentially from the starting point to the ending point along the rotation direction, and the protrusion (303) of the connector (3) contacts the locking link (102); The connector (3) includes a fixed member (301) and a sling (302) that are fixed together. The fixed member (301) is installed on the support rod (104) through a cylinder, and the sling (302) is installed on the armature (103) through a cylinder. Several fasteners (301) and several slings (302) are provided, and the several slings (302) are distributed in a matrix. The elastic sheet (4) is initially bent, and both ends of the elastic sheet (4) are rotatably connected to the fixing member (301) close to it by a connecting rod. The protrusion (303) of the connector (3) is eccentrically positioned with respect to the support rod (104), and the support rod (104) is closer to the end of the protrusion (303) with a smaller radius. The protrusion (303) of the connector (3) is provided with a groove (5) that is conjugate to the outer periphery of the protrusion (303); When the iron core (101) attracts the armature (103), the armature (103) will drive the connected connector (3) to move. One end of the connector (3) is sleeved on the support rod (104) through the fixing piece (301). The connector (3) rotates around the support rod (104). One end of the connector (3) near the support rod (104) has a "6"-shaped protrusion (303). At this time, the protrusion (303) serves as the end of the connector (3) near the support rod (104). The connecting piece (3) begins to rotate around the support rod (104); when the protrusion (303) rotates around the support rod (104), its radius increases sequentially from the starting point to the ending point along the direction of rotation, and the protrusion (303) of the connecting piece (3) contacts the bottom end of the locking link (102). The groove (5) arc surface of the protrusion (303) will continuously push the locking link (102) to make a linear motion. The locking link (102) originally locked the moving contact, but it will be unlocked after being pushed.

2. The overcurrent protection relay according to claim 1, characterized in that: The armature (103) initially has a gap with the iron core (101). When the iron core (101) attracts the armature (103), the two form a surface contact.

3. An overcurrent protection relay according to claim 1, characterized in that: The locking link (102) is located in the groove (5) and contacts the groove (5) in the protrusion (303).

4. An overcurrent protection relay according to claim 1, characterized in that: The armature (103) and the core (101) are collinear.

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