GB/T 14229-2021 English PDFUS$629.00 · In stock
Delivery: <= 6 days. True-PDF full-copy in English will be manually translated and delivered via email. GB/T 14229-2021: Test method of surface contact strength for gear load capacity Status: Valid GB/T 14229: Historical versions
Basic dataStandard ID: GB/T 14229-2021 (GB/T14229-2021)Description (Translated English): Test method of surface contact strength for gear load capacity Sector / Industry: National Standard (Recommended) Classification of Chinese Standard: J17 Word Count Estimation: 34,310 Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration GB/T 14229-2021: Test method of surface contact strength for gear load capacity---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.(Gear contact fatigue strength test method) ICS 21.200 CCSJ17 National Standards of People's Republic of China Replace GB/T 14229-1993 Gear contact fatigue strength test method Released on 2021-05-21 2021-12-01 implementation State Administration of Market Supervision and Administration Issued by the National Standardization Management Committee Table of contentsForeword Ⅲ 1 Scope 1 2 Normative references 1 3 Terms and definitions, code 1 4 Test principle 3 5 Test purpose 4 5.1 Determination of basic data 4 5.2 Performance comparison 4 5.3 Other 5 6 Test method 5 6.1 Overview 5 6.2 Conventional group method 6 6.3 Fewer points combination method 6 6.4 Lifting and Variable Load Method 7 6.5 Ladder increase method 8 6.6 Other methods 8 6.7 Comparison of test methods 8 7 Test equipment 9 7.1 Testing machine 9 7.2 Test gear 10 8 Failure criterion 11 8.1 Discriminant method 11 8.2 Criteria 11 9 Test procedure 12 9.1 Preparation 12 9.2 Preliminary test 12 9.3 Formal test 12 9.4 Supplement and removal of test points 13 9.5 Failure Analysis 13 10 Statistical processing of test data 13 10.1 Conventional group method and few-point combination method 13 10.2 Lifting and Variable Load Method 16 10.3 Step-by-step loading method 16 11 Test report 17 Appendix A (Informative) Statistical Processing Method Considering Confidence Level 18 Appendix B (informative) Data processing example of conventional group method 20 Appendix C (informative) Data processing example of lifting and variable loading method 25 Appendix D (informative) Example of data processing with step-by-step loading method 27 References 29 Gear contact fatigue strength test method1 ScopeThis document specifies the principles, objectives, methods, equipment, failure criteria, procedures, and data for the contact fatigue strength test of involute cylindrical gears. According to processing and test reports. This document is suitable for determining the basic data required for the design of the contact fatigue bearing capacity of the involute cylindrical gear tooth surface of steel or cast iron, and It is suitable for comparative analysis of the contact fatigue performance of gears under different materials, different processes, and different modification methods. Gears of other materials or non Similar tests for involute gears can be used as reference.2 Normative referencesThe contents of the following documents constitute the indispensable clauses of this document through normative references in the text. Among them, dated quotations Only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to This document. GB/T 1356 Standard basic rack tooth profile for cylindrical gears for general machinery and heavy machinery GB/T 3358.1 Statistics Vocabulary and Symbols Part 1.General Statistical Terms and Terms Used in Probability GB/T 3480.1 Calculation of load-carrying capacity of spur gears and helical gears Part 1.Basic principles, overview and general influence coefficients GB/T 3480.2 Calculation of load-bearing capacity of spur gears and helical gears Part 2.Calculation of tooth surface contact strength (pitting) GB/T 10095 (all parts) Cylindrical gear precision system JB/T 8831 Lubricant Selection Method for Industrial Closed Gears 3 Terms and definitions, code names The terms and definitions defined in GB/T 3358.1, GB/T 3480.1 and GB/T 3480.2 and the codes in Table 1 apply to this document. Table 1 Code, meaning and unit ---Surface treatment (such as coating, shot peening, super finishing, etc.); ---Manufacturing processes; ---Gear geometry parameters; ---Tooth surface modification; ---lubricating oil; ---Operating temperature; ---Pitch circle line speed. 5.2.2 According to the comparison of 5.2.1, the material, technology and lubrication conditions of the gear can be optimized. In order to improve efficiency, it is advisable to Test under limited life stress level. The number of test points should be determined according to the dispersion of test results. The number of test points for each comparison is inappropriate Less than five. 5.2.3 If it is necessary to compare the endurance fatigue limit stress, the test shall be carried out in accordance with the requirements of 6.4 or 6.5. 5.3 Other Except for 5.1 and 5.2, other test purposes can be set by the researchers themselves. For example, discuss the failure mechanism of gear contact fatigue, and make Suppression method of fixed tooth surface damage, etc.6 Test method6.1 Overview 6.1.1 When contact fatigue failure occurs on the tooth surface, or the number of stress cycles reaches the cycle base N0 and the tooth surface does not fail (referred to as the "exit point"), The test is terminated and a life value under the current test stress value is obtained, forming a data set (called "test point"). When the test process is the same Usually, the test point is called the "effective test point", otherwise it is called the "abnormal test point". 6.1.2 There are a variety of data combination methods for gear contact fatigue tests, such as conventional group method, few-point combination method, lifting variable load method, and step increase load method. Wait. In the development stage of the test plan, a reasonable selection should be made according to the test purpose and test period. 6.1.3 The contact stress of the tooth surface of the test gear shall be calculated according to the formula (1) according to GB/T 3480.1 and GB/T 3480.2 (where. "" is used For external gearing, "-" is used for internal gearing). σH= ZH·ZE·Zε·Zβ ZV·ZL·ZR·ZW·ZX Ftu±1 ·KA·Kγ·Kv·KHα·KHβ d1·b·u (1) Where. ZH ---node area coefficient; ZE --- coefficient of elasticity; Zε ---coincidence coefficient for calculation of contact strength; Zβ --- helix angle coefficient for contact strength calculation; ZV ---speed coefficient; ZL ---Lubricant coefficient; ZR --- Roughness coefficient calculated by contact strength; ZW --- working hardening coefficient of tooth surface; ZX --- size factor for calculation of contact strength; Ft --- Tangential load on the upper end face of the index circle, in Newton (N); KA ---use factor; Kγ --- Average load factor, Kγ=1 in this document; Kv --- dynamic load factor; KHα---the load distribution coefficient between teeth when calculating the contact strength; KHβ---Helix load distribution coefficient when calculating contact strength; 8.2.2 For case hardened gears (including carburizing, nitriding, carbonitriding, flame or induction hardened gears), pitting corrosion generally occurs first in a few teeth. Appeared on the surface. The set pitting damage limit value is shown in formula (6) and formula (7). RS=4% (6) RT=0.5% (7) When the value of formula (6) is reached, the corresponding gear should be judged to be invalid; when the value of formula (7) is reached, the gear pair should be judged to be invalid. 8.2.3 Tooth surface stress cycle base N0 is generally set to 5×107.When the number of test stress cycles reaches N0 and the tooth surface pitting does not reach damage At the limit, the test can be stopped and it is determined that the test point is exceeded.9 Test procedure9.1 Preparation 9.1.1 Determine the purpose of the test, formulate the test plan according to the test gear manufacturing and inspection technical documents, select the test type and determine the test method. 9.1.2 Visual inspection after cleaning the test gear, the tooth surface must not have corrosion, rust or other forms of damage, and then respond to the test gear and gear teeth. And the tooth surface are numbered. 9.1.3 Check the testing machine. 9.1.4 Install the test gear according to the requirements of the test machine. 9.2 Preliminary test 9.2.1 Check the contact condition of the tooth surface of the test gear. After being loaded to the test load, the contact spots on the tooth surface should not be less than the width of the working tooth 90%, along the tooth height direction should not be less than 80%. 9.2.2 Carry out a running-in test for a certain time (not less than 2h) with a load value lower than 50% of the estimated contact fatigue limit stress. Observe the operation. 9.2.3 According to the requirements of Chapter 6, the test stress levels are divided. If necessary, one or two test points should be tested for each stress level in advance. Determine the rationality of the stress level setting. 9.3 Formal test 9.3.1 The formal test shall be started according to the stress level determined by the preliminary test. 9.3.2 During the test, attention should be paid to the operation of the testing machine, and the quality, flow, and temperature of the lubricating oil should be monitored. Unchangeable in the test The loaded testing machine should monitor the load change, shut down at any time according to the degree of load drop, adjust and restore the load, and make detailed records. 9.3.3 During the test, the interval of tooth surface inspection shall be determined according to the magnitude of the stress level. At the beginning of the test, a 10x magnifying glass can be used to observe the tooth surface, and It should be handled as follows. a) If pitting damage is found but the damage limit has not been reached, continue the test and check it later according to the damage morphology and expansion trend. The time interval; b) If the pitting area rate exceeds the damage limit, the midpoint of the inspection interval is taken as the end of the tooth surface failure time; c) If other damages occur early during the test, such as abnormal wear, slight bonding, etc., record the damage changes in detail, and modify Good lubrication conditions and operating parameters; d) If there is moderate or above wear, gluing, or tooth fracture, the gear is judged as non-contact fatigue failure, and this set of data cannot be used for For the test point. 9.3.4 The pitting corrosion damage morphology, location, tooth surface serial number and stress cycle times shall be tracked and inspected, and records shall be made (e.g. coating or Take pictures).Appendix A(Informative) Statistical processing method considering the degree of confidence A.1 Determine the parameters of the CRSN curve using the conventional group method A.1.1 Interpretation The CRSN curve is the RSN curve considering the degree of confidence, that is, the curve of "confidence-reliability-stress-number of cycles". A.1.2 Calculation of the lower confidence limit of the reliable life The calculation of different distribution forms is as follows. a) For the normal distribution, considering the confidence level C (C≥50%), the calculation of the one-sided lower confidence limit of the reliable life is shown in the formula (A.1). NL,R,C=μN kR,CσN (A.1) Where. μN --- the population mean of the normal distribution function; kR, C---the one-sided tolerance coefficient of normal distribution, its value is related to the number of test points n, the confidence C and the reliability R, see Appendix A of GB/T 4885-2009; σN --- The population standard deviation of the normal distribution function. b) For the lognormal distribution, the calculation of the one-sided lower confidence limit of the reliable life is shown in formula (A.2). NL,R,C=exp[μlnN kR,CσlnN] (A.2) Where. μlnN --- Logarithmic mean of the population of the lognormal distribution function; σlnN --- The logarithmic standard deviation of the population of the lognormal distribution function. c) For the Weibull distribution, Pl NL is the one-sided lower confidence limit of the failure probability P NL when the confidence level is C, see formula (A.3). Pl NLi = i/ni 1 i/ni 1 F1-C,2(ni 1),2i (A.3) Where. F1-C,2(ni 1),2i ---the value of F distribution when the degrees of freedom are 2n-i 1 and 2i, and Pl F2 (ni 1), 2i > F1-C, 2 (ni 1), 2i > 1-C. According to 10.1.2~10.1.4, the life distribution function assumption, fitting and reliable life calculation are carried out. A.1.3 CRSN curve fitting A.1.3.1 The following formula should be used to fit the SN curve, see formula (A.4). σmH·NL,R,C=C (A.4) Where. m --- the exponent of the SN curve equation; C ---SN curve equation constant. A.1.3.2 Take the "stress-cycle times" with the same reliability and confidence of each stress level as the sub-sample, and use the least squares method to fit, and obtain a Series of CRSN curves with different confidence and reliability. A.2 Determine the fatigue limit stress using the lifting and variable load method The calculation of the lower confidence limit of the fatigue limit stress with a confidence of C and a reliability of R is shown in formula (A.5). σR,C=μσ kR,Csσ (A.5) Where. μσ---average value of stress; sσ ---Stress standard deviation. ......Tips & Frequently Asked Questions:Question 1: How long will the true-PDF of GB/T 14229-2021_English be delivered?Answer: Upon your order, we will start to translate GB/T 14229-2021_English as soon as possible, and keep you informed of the progress. The lead time is typically 4 ~ 6 working days. 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