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CN-121994184-A - Contact surface roughness prediction method based on three-section decay function

CN121994184ACN 121994184 ACN121994184 ACN 121994184ACN-121994184-A

Abstract

The invention discloses a contact surface roughness prediction method based on three-section decay functions, which comprises the following steps of 1, measuring relay contact roughness of different action times under a rated working condition and a 2-time rated overload working condition, 2, predicting a contact surface roughness change rule under the rated working condition and the 2-time rated overload working condition by using the three-section decay functions to obtain a contact roughness prediction calculation model under the rated condition and the 2-time rated overload working condition, and 3, fitting the contact surface roughness change condition of the working condition between the rated working condition and the 2-time rated overload working condition to obtain a contact roughness prediction calculation model under the rest load condition. The invention can accurately predict the change degree of the contact surface roughness under certain working conditions based on the measured data, can obtain the change of the contact surface roughness of the nominal state, the 2 times nominal overload state and the working conditions between the nominal state and the nominal overload state through fitting, and can evaluate the contact performance and the contact resistance of the contact more efficiently.

Inventors

  • ZHANG YUCHEN
  • YOU JIAXIN
  • QIAO YUFEI
  • LI BO
  • WANG SHUYI
  • JIN XINYU

Assignees

  • 哈尔滨工业大学

Dates

Publication Date
20260508
Application Date
20260123

Claims (7)

  1. 1. The contact surface roughness prediction method based on the three-section decay function is characterized by comprising the following steps of: Step 1, measuring the roughness of the contact points of the relay with different action times under the rated working condition and the 2 times of rated overload working condition to obtain the surface roughness change data of the contact points; Step 2, predicting the change rule of the contact surface roughness under the rated working condition and the 2-time rated overload working condition by utilizing three-section attenuation functions according to the contact surface roughness change data, and obtaining a contact roughness prediction calculation model under the rated state and the 2-time rated overload state; And 3, fitting the contact surface roughness change condition of the working condition between the rated working condition and the 2-time rated overload working condition based on the three-section attenuation function, and obtaining a contact roughness prediction calculation model under the 1-2-time rated overload condition.
  2. 2. The contact surface roughness prediction method based on three-stage decay function of claim 1, wherein the specific steps of step 1 are as follows: step 1-1, measuring the surface roughness of at least 10 groups of relays when not working; Step 1-2, under rated load, determining the action times according to the average life expectancy under the rated working condition of the relay, measuring the surface roughness of the contact after every 1000 actions, directly ending the experiment if the relay fails and recording the working times at the moment, and prolonging the experiment if the relay does not fail after reaching the preset action times, and still recording the roughness at intervals of every 1000 times until the relay fails; and under the condition of 2 times rated overload of the relay, determining the action times according to the average life expectancy of the relay under the 2 times rated overload working condition, measuring the surface roughness of the contact after each 100 actions, directly ending the experiment if the relay fails, recording the working times at the moment, and prolonging the experiment if the relay still fails after reaching the preset action times, and recording the roughness still at intervals of 100 times until the relay fails.
  3. 3. The contact surface roughness prediction method based on three-segment decay function of claim 1, wherein the three-segment decay function has the following calculation formula: ; in the formula, For the initial average roughness of the sheet material, For the average roughness at the end of the initial phase, For the average roughness at the end of the wave phase, In order to average the roughness at the time of failure, In order to initiate the number of times the working phase ends, In order to stabilize the number of times the working phase is ended, In order to be able to work for the number of times of failure, And As the roughness attenuation coefficient, the degree of roughness, For the amplitude of the wave motion, Is a random perturbation term.
  4. 4. The contact surface roughness prediction method based on three-stage decay function of claim 3, wherein the specific steps of said step 2 are as follows: step 2-1, obtaining initial roughness according to the surface roughness measured in the step 1 when the relay is not in operation ; Step 2-2, determining according to experimental data and the contact surface roughness 、 、 And reach 、 、 Roughness corresponding to the next time 、 、 And determining the coefficients of the three-section decay function formula according to experimental data.
  5. 5. The contact surface roughness prediction method based on three-stage decay function of claim 1, wherein the specific steps of step 3 are as follows: according to the number of times of ending each stage determined under rated working condition 、 、 And average roughness at the beginning of each stage 、 、 And determined in case of 2 times rated overload 、 、 And 、 、 Determining intermediate operating states from power function interpolation 、 、 And 、 、 。
  6. 6. The method for predicting the surface roughness of a contact based on a three-stage decay function of claim 1, wherein in said step 3, the rated overload is 1 to 2 times 、 、 And 、 、 The calculation formula of (2) is as follows: Wherein, the 、 For the number of ends of the initial working phase at rated load and 2 times rated overload, 、 For the average roughness at the end of the initial working phase at rated load and 2 times rated overload, 、 For the number of ends of the steady operation phase at rated load and 2 times rated overload, 、 For the average roughness at the end of the steady-state operating phase at rated load and 2 times rated overload, 、 For rated load and failure times at 2 times rated overload, 、 The average roughness of the relay contacts is the average roughness of the relay contacts when the relay contacts fail under rated load and2 times of rated overload.
  7. 7. The three-segment decay function based contact surface roughness prediction method as in claim 6, wherein said contact surface roughness is characterized by , wherein, As a result of the load factor, For the rated current to be the same, Is the actual operating current.

Description

Contact surface roughness prediction method based on three-section decay function Technical Field The invention belongs to the technical field of relays, relates to a relay surface roughness prediction method, and in particular relates to a contact surface roughness prediction method based on a three-section decay function. Background The surface morphology of the relay contacts directly determines the stability and reliability of the relay contact performance. The smooth and clean contact surface can reduce contact resistance, promote conductive efficiency and reduce joule heat loss, while the rough surface is easy to form microscopic protrusions and depressions, so that the actual contact area between contacts is reduced, the contact resistance is suddenly increased, and even local overheating and fusion welding failure are caused. In the working process of the contact, a series of cumulative changes can occur on the surface state of the contact, namely, an arc generated in the moment of switching on and off of the relay can melt the contact, and concave-convex shapes such as melting pits, burrs and the like are formed after cooling. If an oxide film exists on the surface of the contact, the electric arc in the on-off moment is more easily concentrated at the weak part or the damage point of the film layer, the melting and evaporation of local metal are increased, the loss of contact materials and the degradation of surface morphology are accelerated, and the service life of the contact is shortened. As the contact acts, the contact surface roughness may continuously increase, resulting in degradation of contact performance, continuous increase in contact resistance, damage to the conductive path, and eventually failure of the contact. Disclosure of Invention In order to accurately predict the contact surface roughness, the invention provides a contact surface roughness prediction method based on a three-section decay function. The method can evaluate the change of the surface roughness of the contact under a certain working condition, and is convenient for evaluating the contact performance of the relay. The invention aims at realizing the following technical scheme: A contact surface roughness prediction method based on a three-section decay function comprises the following steps: Step 1, measuring the roughness of the contact points of the relay with different action times under the rated working condition and the 2 times of rated overload working condition to obtain the roughness change data of the contact points, wherein the specific steps are as follows: step 1-1, measuring the surface roughness of at least 10 groups of relays when not working; Step 1-2, under rated load, determining the action times according to the average life expectancy under the rated working condition of the relay, measuring the surface roughness of the contact after every 1000 actions, directly ending the experiment if the relay fails and recording the working times at the moment, and prolonging the experiment if the relay does not fail after reaching the preset action times, and still recording the roughness at intervals of every 1000 times until the relay fails; Under the condition of 2 times rated overload, determining the action times according to the average life expectancy of the relay under the 2 times rated overload working condition, measuring the surface roughness of the contact after each 100 actions, directly ending the experiment if the relay fails and recording the working times at the moment, and prolonging the experiment if the relay still fails after reaching the preset action times, and recording the roughness still at intervals of 100 times until the relay fails; And 2, predicting the change rule of the surface roughness of the contact under the rated working condition and the 2-time rated overload working condition by utilizing three-section attenuation functions according to the change data of the surface roughness of the contact, and obtaining a contact roughness prediction calculation model under the rated state and the 2-time rated overload state, wherein the three-section attenuation functions have the following formulas: ; in the formula, For the initial average roughness of the sheet material,For the average roughness at the end of the initial phase,For the average roughness at the end of the wave phase,In order to average the roughness at the time of failure,In order to initiate the number of times the working phase ends,In order to stabilize the number of times the working phase is ended,In order to be able to work for the number of times of failure,AndAs the roughness attenuation coefficient, the degree of roughness,For the amplitude of the wave motion,Is a random disturbance term; And 3, fitting the contact surface roughness change condition of the working condition between the rated working condition and the 2-time rated overload working condition based on the three-section attenuation function