CN-121997652-A - Low-thermal-disturbance thermal test method for sealed electromagnetic relay

CN121997652ACN 121997652 ACN121997652 ACN 121997652ACN-121997652-A

Abstract

The invention discloses a thermal test method of a low-thermal-disturbance sealed electromagnetic relay, which comprises the following steps of S1, calculating space and time thermal changes based on finite element simulation data, screening an optimal area by combining a pareto rule, locking a temperature center by calculating the Euclidean distance of a shortest plane, determining an opening coordinate, S2, constructing a low-thermal-disturbance channel, implanting a thermocouple, carrying out instantaneous positioning on a lead wire by adopting a rapid curing agent in sequence, backfilling and sealing a pore by adopting a backfilling medium, reconstructing an airtight boundary and a thermal conduction layer of the relay in situ, and S3, extracting and outputting a temperature-time change curve of a key measuring point. The invention solves the technical problems that in the existing metal sealing relay temperature rise test technology, the surface measurement cannot accurately acquire the internal core temperature, and the traditional open pore measurement damages the original air tightness and convection heat dissipation environment of the relay, so that test data is distorted and coverage range is incomplete.

Inventors

YOU JIAXIN
Wang aobo
RUAN YONGGANG
NIU LEI
XUE YUTONG
Fan Pengshuai

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260508
Application Date: 20260119

Claims (9)

1. The method for testing the heat of the sealed electromagnetic relay with low heat disturbance is characterized by comprising the following steps of: Step S1, locking the open-pore coordinates based on two-dimensional plane mapping and space-time feature dual optimization, namely calculating space and time thermal variation based on finite element simulation data, screening an optimal region by combining a pareto rule, locking a temperature center by calculating the Euclidean distance of the shortest plane, and determining the open-pore coordinates; S2, constructing a low thermal disturbance channel and repairing an airtight-thermal field in situ, namely constructing the low thermal disturbance channel, implanting a thermocouple, sequentially adopting a rapid curing agent to carry out instantaneous positioning on a lead, backfilling and sealing a pore by a backfilling medium, and reconstructing an airtight boundary and a heat conduction layer of the relay in situ; and S3, performing thermal data space-time mapping, namely extracting and outputting a temperature-time change curve of the key measuring point.
2. The method for testing the heat of the sealed electromagnetic relay with low heat disturbance according to claim 1, wherein the specific steps of the step S1 are as follows: S1-1, importing a three-dimensional model of a sealed relay into a finite element numerical simulation platform, performing full-time-domain transient thermal analysis, extracting grid node data of the surface of a relay shell, and projecting or unfolding the grid node data into a two-dimensional plane coordinate system; step S1-2, constructing a two-dimensional global node set : Wherein, the For any node in the set, for the total number of nodes in the plane ( ) Two sets of characteristic data are included: Plane coordinate features: Representing the position of the node on the two-dimensional expansion surface. Thermal time domain features: representing the full time domain temperature response sequence corresponding to the node, Time is; s1-3, extracting steady-state temperature of each node at heat balance moment Calculating planar temperature gradient modulus at each node using a two-dimensional differential operator Pair aggregation The plane temperature gradient values of all the nodes in the array are arranged in ascending order, and the nodes with 20 percent of the nodes which are ranked forward are directly selected according to the pareto rule to construct a space steady-state node set ; Step S1-4, for aggregation Calculating the time domain fluctuation of the temperature-time response curve of each node in the network Pair of sets Fluctuation amount of all nodes in the network Performing ascending order arrangement, directly selecting 20% of nodes with the top order according to the pareto rule, and constructing a time domain response node set ; Step S1-5, pair aggregation And (3) with Taking the mathematical intersection to obtain a two-dimensional space-time optimal set : If the intersection contains a plurality of discrete areas, selecting a two-dimensional connected subdomain with the largest area; s1-6, in order to ensure that the perforated point has the maximum plane machining fault tolerance, locking a temperature center by adopting a two-dimensional boundary distance conversion algorithm: Planar boundary extraction, identifying two-dimensional regions Is used for constructing boundary node set The plane coordinates of the method are characterized in that , ; Plane safety margin calculation, namely traversing each node in the area Calculate it to boundary set The shortest planar Euclidean distance of (2) is defined as the punching distance Searching in a planar domain The node with the highest value is defined as the temperature center, and the coordinates of the node are recorded as the position of the opening.
3. The low thermal disturbance sealed electromagnetic relay thermal test method according to claim 2, wherein the low thermal disturbance sealed electromagnetic relay thermal test method comprises the following steps of The calculation formula of (2) is as follows: 。
4. The low thermal disturbance sealed electromagnetic relay thermal test method according to claim 2, wherein the low thermal disturbance sealed electromagnetic relay thermal test method comprises the following steps of The calculation formula of (2) is as follows: in the formula, Is the simulation end time.
5. The low thermal disturbance sealed electromagnetic relay thermal test method according to claim 2, wherein the low thermal disturbance sealed electromagnetic relay thermal test method comprises the following steps of The calculation formula of (2) is as follows: 。
6. The method for testing the heat of the sealed electromagnetic relay with low heat disturbance according to claim 1, wherein the specific steps of the step S2 are as follows: s2-1, selecting a precise micro drill bit or laser drilling equipment with a depth limiting ring according to the temperature center coordinates output in the step S1, and carrying out layer-by-layer depth fixing processing on a metal shell of the relay and an insulation framework layer possibly existing in the relay; S2-2, after the channel is processed and the smooth and burr-free hole wall is confirmed, selecting a thermocouple as a sensor, and slowly feeding the thermocouple through the micropores until the temperature sensing end accurately touches an internal preset temperature measuring point; s2-3, dispensing operation is carried out at the position where the thermocouple lead penetrates out of the orifice of the metal shell by adopting a quick curing agent; S2-4, after the position of the lead is fixed and locked, slowly injecting a fluid backfill medium from the micropore gap by using a precise dispensing injector with a micro needle until the channel is completely filled and slightly protruded on the surface of the shell, and forming an elastic elastomer filling layer after the backfill medium is completely solidified.
7. The method for testing the heat of the sealed electromagnetic relay with low heat disturbance according to claim 6, wherein the thermocouple is a T-type thermocouple or a K-type thermocouple.
8. The method for testing the heat of the sealed electromagnetic relay with low heat disturbance according to claim 6, wherein the backfill medium is silicon rubber.
9. The method for thermal testing of a low thermal disturbance sealed electromagnetic relay according to claim 1, wherein the specific steps of step S3 are as follows: step S3-1, a thermocouple testing platform is built, and a thermocouple signal wire pre-buried in the step S2 is connected into a multichannel data acquisition instrument, so that good contact is ensured; S3-2, setting a test time sequence and a high-frequency sampling frequency according to the thermal inertia characteristics of the sealing relay, and completely capturing transient temperature rise details at the moment of electrifying; and S3-3, applying rated load to the sealing relay and synchronously triggering an acquisition instruction, recording and storing discrete temperature data of the internal thermocouple in real time, and extracting and outputting a temperature-time change curve of the key measuring point.

Description

Low-thermal-disturbance thermal test method for sealed electromagnetic relay Technical Field The invention belongs to the technical field of electrical element testing, relates to a thermal testing method of a sealed electromagnetic relay, and particularly relates to a global thermal testing method of a sealed relay based on low-thermal-disturbance tapping and infrared coupling. Background Electromagnetic relays are used as core basic elements in automatic control circuits and are widely applied to the fields of high reliability such as aerospace, electric power protection and rail transit. In order to meet the requirements of air tightness, electromagnetic shielding and environmental corrosion resistance, the relay is generally packaged in a full-sealing way by adopting a metal shell. The coil and contacts inside the relay are the primary sources of heat during long-term operation or overload conditions. If the internal temperature rise exceeds the tolerance limit of the insulating material or causes fatigue of the internal welding spots, the safety and reliability of the system are seriously affected. At present, the temperature rise test for the sealing relay mainly adopts the following several prior technologies, but the practical application has obvious technical limitations: 1. The surface contact measurement method and the limitation thereof are that the prior art mostly attaches a sensor to the surface of a metal shell for indirect measurement. However, in order to meet electrical safety standards, an insulating air gap must exist between the high voltage heat generating components inside the relay and the metal housing. This layer of air medium constitutes a significant thermal conduction resistance, with a significant numerical decay and time lag of the shell temperature relative to the internal core temperature. By the measurement mode, an accurate heat conduction model is difficult to build, and the real thermal response of the internal core component under transient overload cannot be accurately known. 2. In order to directly explore the temperature rise condition of the inner core component, the traditional process usually adopts an invasive measurement mode of opening a metal shell or drilling a large hole. However, this method has a fundamental defect of "breaking the airtight environment to cause data distortion". For the inflatable sealing relay, physical shell opening inevitably leads to leakage of high-voltage insulating gas and sudden drop of sealing pressure intensity in the interior, and thoroughly damages the original gas insulating property and natural convection heat exchange model of the relay. The thermal conduction boundary conditions of the temperature data measured in the non-sealing and low-pressure environment are quite different from the actual working conditions, and the actual thermal performance of the product in the sealing running state cannot be represented, so that the effectiveness as the basis for shaping the product is lost. In summary, the existing relay thermal test technology faces the dilemma of "surface indirect measurement has temperature difference" and "open shell direct measurement breaks seal". Especially, the prior art generally lacks of numerical calculation and instruction of simulation theory, so that the selection of temperature measuring points often depends on experience or random blindness, and the original airtight heat dissipation environment cannot be maintained after invasive measurement. Therefore, development of a test method capable of realizing internal accurate temperature measurement by utilizing numerical calculation scientific fixed points and through a low-heat disturbance process is urgently needed. Disclosure of Invention The invention provides a low-thermal-disturbance heat testing method of a sealed electromagnetic relay, and aims to solve the technical problems that in the existing metal sealed relay temperature rise testing technology, surface measurement cannot accurately acquire the internal core temperature, and traditional open pore measurement damages the original air tightness and convection heat dissipation environment of the relay, so that testing data is distorted and coverage is incomplete. The invention aims at realizing the following technical scheme: A low-thermal-disturbance thermal test method for a sealed electromagnetic relay comprises the following steps: Step S1, locking the open-pore coordinates based on two-dimensional plane mapping and space-time characteristic dual optimization, namely calculating space and time thermal variation based on finite element simulation data, screening an optimal area by combining a pareto rule, locking a temperature center by calculating the Euclidean distance of the shortest plane, and determining the open-pore coordinates, wherein the method comprises the following specific steps of: S1-1, importing a three-dimensional model of a sealed relay into a finite element numerical