Thermal test method for sealed electromagnetic relay with low thermal disturbance

Abstract

The invention discloses a sealed electromagnetic relay thermal test method with low thermal disturbance, and the method comprises the following steps: S1, calculating space and time domain thermal changes based on finite element simulation data, screening an optimal region in combination with a Pareto rule, locking a temperature center through calculating a shortest plane Euclidean distance, and determining a hole opening coordinate; step S2, constructing a low thermal disturbance channel and implanting a thermocouple, carrying out instantaneous positioning on the lead by adopting a rapid curing agent in sequence, carrying out backfill sealing on the pores by adopting a backfill medium, and carrying out in-situ reconstruction on an airtight boundary and a heat conduction layer of the relay; and S3, extracting and outputting a temperature-time change curve of the key measuring point. The technical problems that in an existing metal sealing relay temperature rise testing technology, the internal core temperature cannot be accurately obtained through surface measurement, the original air tightness and the convection heat dissipation environment of the relay are damaged through traditional trepanning measurement, and consequently testing data are distorted, and the coverage range is incomplete are solved.

Description

Technical Field

[0001] This invention belongs to the field of electrical component testing technology, and relates to a thermal testing method for a sealed electromagnetic relay, specifically a full-range thermal testing method for a sealed relay based on low thermal disturbance opening and infrared coupling. Background Technology

[0002] Electromagnetic relays, as core components in automatic control circuits, are widely used in high-reliability fields such as aerospace, power protection, and rail transportation. To meet requirements for airtightness, electromagnetic shielding, and resistance to environmental corrosion, these relays are typically encapsulated in a fully sealed metal casing. Under long-term operation or overload conditions, the coil and contacts inside the relay are the main heat sources. If the internal temperature rise exceeds the tolerance limit of the insulating material or causes fatigue of the internal solder joints, it will seriously affect the safety and reliability of the system.

[0003] Currently, the temperature rise test for this type of sealed relay mainly employs the following existing technologies, but all of them have significant technical limitations in practical applications:

[0004] 1. Surface Contact Measurement Method and its Limitations: Existing technologies mostly involve attaching sensors to the surface of a metal casing for indirect measurement. However, to meet electrical safety standards, an insulating air gap must exist between the high-voltage heating components inside the relay and the metal casing. This air layer constitutes a significant thermal resistance, causing a substantial numerical decay and time lag in the casing temperature relative to the internal core temperature. This measurement method makes it difficult to establish an accurate heat conduction model and cannot precisely determine the true thermal response of the internal core components under transient overload.

[0005] 2. Destructive Measurement Methods and Their Limitations: To directly investigate the temperature rise of internal core components, traditional processes often employ invasive measurement methods such as opening the metal casing or drilling large holes. However, this method suffers from a fundamental flaw: "damaging the airtight environment leads to data distortion." For gas-sealed relays, physical opening inevitably results in the leakage of internal high-pressure insulating gas and a sudden drop in sealing pressure, completely destroying the relay's original gas insulation characteristics and natural convection heat transfer model. Temperature data measured in this "unsealed, low-pressure" environment has thermal conduction boundary conditions that are drastically different from actual operating conditions, failing to represent the product's actual thermal performance under sealed operating conditions, thus losing its validity as a basis for product designation.

[0006] In summary, existing relay thermal testing technologies face a dilemma: "temperature differences exist in indirect surface measurements" and "direct measurements after opening the casing disrupt the seal." In particular, current technologies generally lack guidance from numerical calculations and simulation theories, leading to temperature measurement point selection often relying on experience or being random and haphazard, failing to maintain the original airtight heat dissipation environment after invasive measurements. Therefore, there is an urgent need to develop a testing method that can scientifically pinpoint measurement using numerical calculations and achieve accurate internal temperature measurement through low-thermal-disturbance processes. Summary of the Invention

[0007] This invention provides a thermal testing method for sealed electromagnetic relays with low thermal disturbance, aiming to solve the technical problems in existing metal-sealed relay temperature rise testing technology, where surface measurement cannot accurately obtain the internal core temperature, and traditional open-hole measurement destroys the original airtightness and convection heat dissipation environment of the relay, resulting in distorted test data and incomplete coverage.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A thermal testing method for a sealed electromagnetic relay with low thermal disturbance includes the following steps:

[0010] Step S1: Hole coordinate locking based on dual optimization of two-dimensional plane mapping and spatiotemporal characteristics: Based on finite element simulation data, spatial and temporal thermal changes are calculated, and the optimal region is selected by combining the Pareto principle. The temperature center is locked by calculating the shortest plane Euclidean distance, and the hole coordinates are determined. The specific steps are as follows:

[0011] Step S1-1: Import the three-dimensional model of the sealed relay into the finite element numerical simulation platform, perform full-time transient thermal analysis, extract the mesh node data of the relay shell surface, and project or unfold it onto the two-dimensional plane coordinate system.

[0012] Step S1-2: Construct a two-dimensional global node set :

[0013]

[0014] in, The total number of nodes in the plane, for any node in the set. ( It contains two sets of feature data:

[0015] Planar coordinate characteristics: , indicating the position of the node on the two-dimensional unfolded surface.

[0016] Thermal time-domain characteristics: This represents the full-time temperature response sequence corresponding to that node. For time;

[0017] Steps S1-3: Extract the steady-state temperature of each node at thermal equilibrium. The plane temperature gradient modulus at each node is calculated using a two-dimensional differential operator. :

[0018]

[0019] For sets The planar temperature gradient values ​​of all nodes are sorted in ascending order. According to the Pareto principle, the top 20% of the nodes are directly selected to construct the spatial steady-state node set. ;

[0020] Steps S1-4: For the set For each node in the equation, calculate the time-domain fluctuation of its temperature-time response curve. :

[0021]

[0022] In the formula, This is the simulation end time; for the set Fluctuation of all nodes Sort the nodes in ascending order and select the top 20% according to the Pareto principle to construct the time-domain response node set. ;

[0023] Steps S1-5: For the set and Taking the mathematical intersection yields the optimal set in two-dimensional spacetime. :

[0024]

[0025] If the intersection contains multiple discrete regions, select the two-dimensional connected subdomain with the largest area.

[0026] Steps S1-6: To ensure the maximum tolerance for planar machining at the opening point, a two-dimensional boundary distance transformation algorithm is used to lock the temperature center.

[0027] Planar boundary extraction: Identifying two-dimensional regions Construct a set of boundary nodes based on the outline boundary. Its planar coordinate characteristics are , ;

[0028] Planar safety margin calculation: Traverse every node within the region Calculate its boundary set The shortest plane Euclidean distance is defined as the punching distance. :

[0029]

[0030] Search within the planar domain The node with the largest value is defined as the temperature center, and its coordinates are recorded as the opening position.

[0031] Step S2, Low Thermal Disturbance Channel Construction and In-situ Repair of Airtightness and Thermal Field: A low thermal disturbance channel is constructed and a thermocouple is implanted. A rapid curing agent is used for instantaneous positioning of the leads, and a backfill medium is used to seal the pores. The airtightness boundary and thermal conductivity layer of the relay are reconstructed in situ. The specific steps are as follows:

[0032] Step S2-1: Based on the temperature center coordinates output in step S1, select a precision micro drill bit or laser drilling equipment equipped with a depth limiting ring to perform layer-by-layer depth processing on the relay metal shell and the insulation skeleton layer that may exist inside.

[0033] Step S2-2: After the channel is processed and the hole wall is confirmed to be smooth and burr-free, select a T-type or K-type thermocouple as a sensor and slowly insert it through the micro-hole until the sensing end accurately touches the preset internal temperature measuring point.

[0034] Step S2-3: Apply a fast-curing agent to the opening where the thermocouple leads pass through the metal casing.

[0035] Step S2-4: After the lead wire position is fixed and locked, use a precision dispensing syringe with a micro needle to slowly inject the fluid backfill medium from the micropore gap until the channel is completely filled and slightly protrudes from the surface of the shell. After the backfill medium is completely cured, an elastic elastomer filling layer is formed.

[0036] Step S3, Spatiotemporal Mapping of Thermal Data: Extract and output the temperature-time variation curves of key measuring points. The specific steps are as follows:

[0037] Step S3-1: Build a thermocouple testing platform and connect the thermocouple signal line pre-embedded in step S2 to the multi-channel data acquisition instrument to ensure good contact.

[0038] Step S3-2: Based on the thermal inertia characteristics of the sealed relay, set the test timing and high-frequency sampling frequency to fully capture the transient temperature rise details at the moment of power-on;

[0039] Step S3-3: Apply the rated load to the sealed relay and synchronously trigger the acquisition command to record and save the discrete temperature data of the internal thermocouple in real time, and extract and output the temperature-time change curves of key measuring points.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. A standardized method for selecting perforation locations in the casing based on simulation optimization has been established. Addressing the "blind selection" of perforation locations in existing technologies, which rely on experience and lack scientific guidance, this invention introduces a scientific selection strategy. By calculating spatial and temporal thermal change characteristics and combining this with the Pareto algorithm, the optimal region with the most uniform temperature distribution and the most linear thermal response is selected. Within this region, the shortest planar Euclidean distance is calculated to obtain the maximum safety margin, thereby accurately determining the temperature measurement center. This method mathematically locks in the optimal perforation location, ensuring that the perforation location is consistent with the relay's operating state.

[0042] 2. Ensuring the authenticity and effectiveness of internal temperature measurements under sealed conditions. Addressing the shortcomings of traditional "destructive measurement by opening the casing," which leads to insulation gas leakage and failure of the natural convection model, this invention employs an in-situ repair process of "precise drilling + thermally conductive sealant backfilling." This method, while implanting the probe, utilizes sealant with thermophysical properties matched to the casing to rebuild the airtight barrier, maintaining the original high-pressure gas insulation environment and natural convection heat transfer boundary inside the relay. Verification has shown that this method ensures that the measured temperature data accurately represents the actual thermal performance of the relay under fully sealed, gas-filled operating conditions. Attached Figure Description

[0043] Figure 1 A schematic diagram of the overall process for thermal testing of sealed electromagnetic relays with low thermal disturbance;

[0044] Figure 2 This is a schematic diagram of the relay contacts and the iron core measuring points;

[0045] Figure 3 This is a schematic diagram of adhesive repair.

[0046] Figure 4 This is the relay temperature-time curve. Detailed Implementation

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0048] This invention provides a low-thermal-disturbance thermal testing method for sealed electromagnetic relays. First, finite element simulation software is used to calculate spatial and temporal thermal change characteristics. Combined with the Pareto algorithm, the optimal region with the most uniform temperature distribution and the most linear thermal response is selected. Within this region, the shortest planar Euclidean distance is calculated to obtain the maximum safety margin, thereby accurately determining the temperature measurement center. Then, through low-thermal-disturbance insertion and in-situ repair technology of the insulating medium, the sealed thermal field boundary of the relay is reconstructed at the physical level. Finally, relay thermal characteristic data with the true internal core temperature rise are constructed, achieving accurate characterization of the thermal behavior of the sealed relay under operating conditions. This invention effectively solves the problem of airtight environment distortion caused by traditional destructive testing by locking the coordinates of low-thermal-disturbance micro-holes through simulation combined with algorithms and micro-hole sealing technology, realizing accurate thermal monitoring of sealed relays under real operating conditions. Figure 1 As shown, the specific steps are as follows:

[0049] Step S1: Hole coordinate locking based on dual optimization of two-dimensional plane mapping and spatiotemporal characteristics: Based on finite element simulation data, spatial and temporal thermal changes are calculated, and the optimal region is selected by combining Pareto's law. The temperature center is locked by calculating the shortest plane Euclidean distance, and the hole coordinates are determined.

[0050] This step aims to treat the relay housing surface as an equivalent two-dimensional planar region and use finite element numerical calculation data to find a temperature center on this plane with the most uniform spatial distribution and the most linear time response, which will serve as the unique coordinate for the physical opening.

[0051] First, the 3D model of the sealed relay is imported into a finite element numerical simulation platform for full-time transient thermal analysis. Mesh node data from the relay housing surface is extracted and projected or unfolded onto a 2D plane coordinate system. A 2D global node set is then constructed. :

[0052]

[0053] in, This represents the total number of nodes in the plane. For any node in the set... ( It contains two sets of feature data:

[0054] Planar coordinate characteristics: , indicating the position of the node on the two-dimensional unfolded surface.

[0055] Thermal time-domain characteristics: This represents the full-time temperature response sequence corresponding to that node. For time (s).

[0056] Extract the steady-state temperature of each node at thermal equilibrium. The plane temperature gradient modulus at each node is calculated using a two-dimensional differential operator. :

[0057]

[0058] For sets The planar temperature gradient values ​​of all nodes are sorted in ascending order. Following the Pareto principle, the top 20% of nodes are selected to construct the spatial steady-state node set. .

[0059] For sets For each node in the equation, calculate the time-domain fluctuation of its temperature-time response curve. :

[0060]

[0061] In the formula, The simulation end time is determined by the actual steady-state response speed. For the set... Fluctuation of all nodes Sort the nodes in ascending order. Following the Pareto principle, directly select the top 20% of the sorted nodes to construct the time-domain response node set. .

[0062] For sets and Taking the mathematical intersection yields the optimal set in two-dimensional spacetime. :

[0063]

[0064] If the intersection contains multiple discrete regions, the two-dimensional connected subdomain with the largest area is selected. To ensure that the opening point has the maximum tolerance for planar machining errors, a two-dimensional boundary distance transformation algorithm is used to lock the temperature center.

[0065] Planar boundary extraction: Identifying two-dimensional regions Construct a set of boundary nodes based on the outline boundary. Its planar coordinate characteristics are , .

[0066] Planar safety margin calculation: Traverse every node within the region Calculate its boundary set The shortest plane Euclidean distance is defined as the punching distance. :

[0067]

[0068] Search within the planar domain The node with the largest value is defined as the temperature center. Finally, this two-dimensional coordinate is obtained as the final opening location.

[0069] Step S2, Low thermal disturbance channel construction and in-situ repair of airtight thermal field: Construct a low thermal disturbance channel and implant a thermocouple, use a fast curing agent to instantaneously position the lead wire, and use silicone rubber to backfill and seal the pores to reconstruct the airtight boundary and thermal conduction layer of the relay in situ.

[0070] Based on the temperature center coordinates output in step S1, a precision micro drill bit or laser drilling equipment equipped with a depth limiting ring is selected to perform layer-by-layer, depth-determined machining on the relay's metal casing and any internal insulating skeleton layers. During the drilling operation, a high-negative-pressure dust extraction device must be activated simultaneously and placed close to the drill bit's working point. For ferromagnetic metal casings, a strong magnetic adsorption fixture can also be used to remove fine metal debris and dust generated during cutting in real time through a dual method of "adsorption + magnetic capture," strictly preventing conductive foreign objects from falling into the relay's internal cavity, contaminating the contacts, or damaging the electrical insulation strength.

[0071] After the channel processing is completed and the hole walls are confirmed to be smooth and burr-free, a T-type or K-type thermocouple with an extremely fine wire diameter and a high-temperature resistant insulating layer is selected as the sensor. It is slowly inserted through a micro-hole until the sensing end precisely contacts the preset internal temperature measurement point. To ensure the stability of the temperature measurement point contact, 606 fast-curing agent is first applied to the opening where the thermocouple lead exits the metal casing. Utilizing the fast curing speed and strong adhesion of 606 curing agent, instantaneous positioning and mechanical anchoring of the thermocouple lead are achieved within seconds, preventing fluid disturbance during subsequent adhesive application from causing displacement or detachment of the internal temperature sensing end.

[0072] After the lead wire position is fixed and locked, the critical airtightness and thermal field repair stage begins. 703 silicone rubber, with its excellent electrical insulation and high / low temperature resistance, is selected as the backfill medium. Using a precision dispensing syringe with a micro-needle, the fluid-like 703 silicone rubber is slowly injected through the micropores, with strict control of the injection speed to ensure the adhesive fully wets the pore walls and displaces residual air, until the adhesive completely fills the channels and slightly protrudes from the outer shell surface. After the 703 silicone rubber absorbs moisture from the air and undergoes a vulcanization reaction at room temperature and fully cures, it forms an elastic elastomer filling layer. This filling layer not only re-seales the micropores in terms of physical structure, rebuilding the airtight barrier boundary of the relay; but also, utilizing the excellent insulation and thermal conductivity properties of 703 silicone rubber, it effectively repairs the thermal conduction break caused by the opening and buffers stress concentration, thereby ensuring that the original gas convection circulation and heat distribution state inside the relay is maintained, achieving low-disturbance restoration of the test environment.

[0073] Step S3, Spatiotemporal mapping of hot data:

[0074] First, a thermocouple testing platform is set up, and the thermocouple signal lines pre-embedded in step S2 are connected to a multi-channel data acquisition instrument, ensuring good contact. Based on the thermal inertia characteristics of the sealed relay, a rigorous test sequence and high-frequency sampling frequency are set to fully capture the transient temperature rise details at the moment of energization. Subsequently, a rated load is applied to the relay and the acquisition command is triggered synchronously, recording and saving the discrete temperature data of the internal thermocouple in real time, and extracting and outputting the temperature-time change curves of key measuring points.

[0075] Example:

[0076] This embodiment uses a single-coil balanced force sealed electromagnetic relay with three sets of changeover contacts as the test object. This relay is hermetically sealed with a metal casing, has one electromagnetic coil and three independent pairs of moving and stationary contacts, and features a compact internal structure and a sensitive balancing force mechanism. The specific implementation steps are as follows:

[0077] Step S1: Layout of housing opening coordinates based on three sets of contact point models:

[0078] First, based on specific thermal testing requirements, two specific internal temperature measurement target points are planned:

[0079] Measurement point A (iron core): Select the non-magnetic pole contact surface on the side of the static iron core of the electromagnetic system to avoid affecting the air gap of the magnetic circuit.

[0080] Test point B (contact): For the three sets of side-by-side contact structures, the normally open stationary contact of the middle set is selected to lead out from the root of the contact plate. The stationary contact is chosen to avoid the complex sweeping stroke of the moving spring in the balancing force mechanism and to prevent the test lead from interfering with the mechanical action.

[0081] Finite element method (FEM) simulation software was used to calculate the spatial and temporal thermal variation characteristics of the outer shell surface. The Pareto algorithm was then used to select the optimal region with the most uniform temperature distribution and the most linear thermal response. Within this region, the shortest planar Euclidean distance was calculated to obtain the maximum safety margin and accurately determine the coordinates of the temperature measurement center. The locations of the contact points, the iron core temperature measurement points, and the shortest Euclidean distance are as follows: Figure 2 As shown.

[0082] Step S2, precision drilling, insulation implantation, and stepped seal repair:

[0083] Based on the temperature measurement center coordinates output in step S1, determine the drilling location and perform physical drilling using a bench drill:

[0084] Step S2-1, Composite Drilling Process: Use a 1.20mm diameter alloy drill bit with low-speed feed, combined with negative pressure dust extraction to drill through the metal shell. Then, use a 90° chamfering tool to slightly cut into the hole opening to create a chamfered band with a diameter of 1.25mm, and thoroughly clean the metal chips inside the hole with compressed air.

[0085] Step S2-2, Sensor Implantation and Double Insulation Protection: Prepare two 0.5mm diameter T-type thermocouples. Insert the two thermocouples into their respective micro-holes: probe A touches the side wall of the stationary iron core; probe B is bonded to the root of the intermediate stationary contact using thermally conductive adhesive.

[0086] Step S2-3, Two-component adhesive repair (606 glue for positioning + 703 glue for sealing):

[0087] Instantaneous positioning (606 adhesive): Adjust the sensor position to ensure good contact at the temperature sensing end and no stress on the leads. Apply a small amount of 606 fast-curing adhesive to the annular gap between the 1.25mm diameter chamfer and the thermocouple circuit. Utilizing the bonding bevel provided by the 90° chamfer, the 606 adhesive cures within 3-5 seconds, firmly locking the thermocouple circuit to the metal shell and providing a tensile-resistant mechanical anchoring effect.

[0088] Deep sealing (703 adhesive): After positioning, inject 703 silicone rubber into the remaining gaps in the hole using a micro-syringe. Because the 1.20mm diameter hole provides sufficient fluid channels, the 703 silicone rubber can smoothly penetrate deep into the hole, displacing residual air. The chamfered edge here acts as a buffer against excess adhesive, ensuring a smooth transition between the cured silicone cap and the outer casing surface. The cured 703 silicone layer rebuilds the relay's airtight boundary and repairs the local heat conduction path of the casing. A schematic diagram of the adhesive repair is shown below. Figure 3 As shown.

[0089] Step S3: Extraction and export of temperature-time curves at key measuring points:

[0090] Step S3-1: Connect the internal channels: Connect the iron core and contact thermocouples to the channels of the data acquisition instrument.

[0091] Step S3-2, Operating Condition Loading: Apply the rated voltage to the coil and apply the rated load current in series to the three sets of contacts. Trigger the acquisition system to simultaneously record the internal temperatures at two points.

[0092] Step S3-3: Import the collected data into the analysis software, align the time axis, and directly extract and export the temperature-time change curve to characterize the thermal characteristics of the relay: extract the real-time temperature data of the iron core sidewall and the root of the intermediate group of stationary contacts respectively, and generate the internal temperature rise trajectory curve, such as... Figure 4 As shown.

Claims

1. A thermal testing method for a sealed electromagnetic relay with low thermal disturbance, characterized in that... The method includes the following steps: Step S1: Hole coordinate locking based on dual optimization of two-dimensional plane mapping and spatiotemporal characteristics: Based on finite element simulation data, spatial and temporal thermal changes are calculated, and the optimal region is selected by combining Pareto's law. The temperature center is locked by calculating the shortest plane Euclidean distance, and the hole coordinates are determined. Step S2, Low thermal disturbance channel construction and in-situ repair of airtight thermal field: Construct a low thermal disturbance channel and implant a thermocouple, use a fast curing agent to instantaneously position the lead wire, and use a backfill medium to backfill and seal the pores, and rebuild the airtight boundary and thermal conduction layer of the relay in situ. Step S3, Spatiotemporal mapping of thermal data: Extract and output the temperature-time change curves of key measuring points.

2. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 1, characterized in that... The specific steps of step S1 are as follows: Step S1-1: Import the three-dimensional model of the sealed relay into the finite element numerical simulation platform, perform full-time transient thermal analysis, extract the mesh node data of the relay shell surface, and project or unfold it onto the two-dimensional plane coordinate system. Step S1-2: Construct a two-dimensional global node set : in, The total number of nodes in the plane, for any node in the set. ( It contains two sets of feature data: Planar coordinate characteristics: , indicating the position of the node on the two-dimensional unfolded surface. Thermal time-domain characteristics: This represents the full-time temperature response sequence corresponding to that node. For time; Steps S1-3: Extract the steady-state temperature of each node at thermal equilibrium. The plane temperature gradient modulus at each node is calculated using a two-dimensional differential operator. For sets The planar temperature gradient values ​​of all nodes are sorted in ascending order. According to the Pareto principle, the top 20% of the nodes are directly selected to construct the spatial steady-state node set. ; Steps S1-4: For the set For each node in the equation, calculate the time-domain fluctuation of its temperature-time response curve. ; For sets Fluctuation of all nodes Sort the nodes in ascending order and select the top 20% according to the Pareto principle to construct the time-domain response node set. ; Steps S1-5: For the set and Taking the mathematical intersection yields the optimal set in two-dimensional spacetime. : If the intersection contains multiple discrete regions, select the two-dimensional connected subdomain with the largest area. Steps S1-6: To ensure the maximum tolerance for planar machining at the opening point, a two-dimensional boundary distance transformation algorithm is used to lock the temperature center. Planar boundary extraction: Identifying two-dimensional regions Construct a set of boundary nodes based on the outline boundary. Its planar coordinate characteristics are , ; Planar safety margin calculation: Traverse every node within the region Calculate its boundary set The shortest plane Euclidean distance is defined as the punching distance. Search within the planar domain The node with the largest value is defined as the temperature center, and its coordinates are recorded as the opening position.

3. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 2, characterized in that... The The calculation formula is: 。 4. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 2, characterized in that... The The calculation formula is: In the formula, This is the simulation end time.

5. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 2, characterized in that... The The calculation formula is: 。 6. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 1, characterized in that... The specific steps of step S2 are as follows: Step S2-1: Based on the temperature center coordinates output in step S1, select a precision micro drill bit or laser drilling equipment equipped with a depth limiting ring to perform layer-by-layer depth processing on the relay metal shell and the insulation skeleton layer that may exist inside. Step S2-2: After the channel is processed and the hole wall is confirmed to be smooth and burr-free, select a thermocouple as a sensor and slowly insert it through the microhole until the sensing end accurately touches the preset internal temperature measuring point. Step S2-3: Apply a fast-curing agent to the opening where the thermocouple leads pass through the metal casing. Step S2-4: After the lead wire position is fixed and locked, use a precision dispensing syringe with a micro-needle to slowly inject the fluid backfill medium from the micropores until it completely fills the channel and slightly protrudes from the outer shell surface. After the backfill medium is completely cured, an elastic elastomer filling layer is formed.

7. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 6, characterized in that... The thermocouple is a type T or a type K thermocouple.

8. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 6, characterized in that... The backfill medium is silicone rubber.

9. The thermal testing method for a sealed electromagnetic relay with low thermal disturbance according to claim 1, characterized in that... The specific steps of step S3 are as follows: Step S3-1: Build a thermocouple testing platform and connect the thermocouple signal line pre-embedded in step S2 to the multi-channel data acquisition instrument to ensure good contact. Step S3-2: Based on the thermal inertia characteristics of the sealed relay, set the test timing and high-frequency sampling frequency to fully capture the transient temperature rise details at the moment of power-on; Step S3-3: Apply the rated load to the sealed relay and synchronously trigger the acquisition command to record and save the discrete temperature data of the internal thermocouple in real time, and extract and output the temperature-time change curves of key measuring points.

Images