GB/T 20736-2006Fatigue test method for transmission precision roller chain (English PDF)

Foreword

This Standard is identical to the international standard ISO 15654.2004, Fatigue test

method for transmission precision roller chains (English version).

Annex A ~ Annex H of this Standard are informative annexes.

This Standard was proposed by China Machinery Industry Federation.

This Standard shall be under the jurisdiction of National Technical Committee 164 on

Chain Drives of Standardization Administration of China (SAC/TC 164).

Organization responsible for the drafting of this Standard. Jilin University (former Jilin

University of Technology).

Organizations participating in the drafting of this Standard. Hangzhou Donghua Chain

Group Co., Ltd., Jiangsu Shuangling Chain Transmission Co., Ltd., Hangzhou Xilin

Chain Manufacturing Co., Ltd., Zhejiang Hengjiu Machinery Group Co., Ltd., KMC

Chain (Shenzhen) Co., Ltd., Qingdao Zhenghe Industrial Co., Ltd.

Main drafters of this Standard. Meng Xiangbin, Ye Bin, Cao Sujian, Ma Jinhua, Shou

Feng, Chen Xinqiang, Jin Yumo.

Participating drafters of this Standard. Wang Hai'ou, Xu Meizhen, Tan Guangcheng,

Wang Zhijun, Meng Danhong, He Mingzong, Fu Zhenming, Wang Ying.

Fatigue test method for transmission precision roller chain

1 Scope

This Standard specifies an axial force fatigue test method for transmission roller chains,

the tests being of the fluctuating tension type, carried out at room temperature in air,

with the force applied along the longitudinal axis of the chain. It also specifies

procedures for statistically analyzing the test results and gives formats and elements for

presenting the results of fatigue tests and analyses.

2 Normative references

The following referenced documents are indispensable for the application of this

document. For dated references, all subsequent amendments (not including errata

content) or revisions do not apply to this standard. However, parties to agreements that

are based on this Standard are encouraged to study whether the latest versions of these

documents can be used. For undated references, the latest edition applies to this

Standard.

GB/T 1243-2006, Short-pitch transmission precision roller and bush chains,

attachments and associated chain sprockets (ISO 606.2004, IDT)

3 Terms and definitions

Symbols, terms, definitions and units are given in Table 1 and Figure 1.

4 Test principle

Fatigue tests are made on transmission roller chains to determine fatigue properties of

chain plates such as those shown on Figure B.1 or to verify conformance to dynamic

strength requirements in GB/T 1243 and GB/T 14212.

5 Test apparatus

The test fixtures shall be capable of transmitting an axial force to the test piece without

inducing a subsidiary force caused by the fixtures. Universal type fixtures shall be used

for fatigue testing of transmission chains.

6 Test specimens

At least 5 free pitches of chain shall be used as a fatigue test specimen, except for

chain pitch over 50.8 mm where a minimum of 3 free pitches are acceptable. Free

pitches are those chain pitches that do not contact the fixtures.

7 Test procedure

For analyses of fatigue test data, maximum forces shall be corrected to zero minimum

force. A test force is obtained by correcting the maximum force to zero minimum force

by means of the Johnson–Goodman method [Equation (3)]. The Johnson–Goodman

relationship is illustrated by Figure 3.

A longitudinal tensile force shall be applied, sinusoidally varying between the minimum

test force determined according to 7.1.1 and the maximum test force determined

according to 7.1.2.The fatigue test shall continue to endurance or until the specimen

fails without reaching the endurance.

8 Staircase test data analysis

It is customary to tabulate and plot the data as a staircase test progresses to ensure that

the rules for constructing a staircase are followed. An example of such a data plot (three

levels and 95% confidence level) is shown in Table 3.

The standard deviations of the staircase data shall be calculated using Equation (7).

The fatigue limit of the staircase test shall be calculated using Equation (8).

9 Report of test results

The originator shall provide to the user the following.

The originator shall provide to the user the following.

Annex A

(informative)

Survival test with abridged Probit analysis

The purpose of the survival test with abridged Probit analysis is determine the mean

fatigue limit and its standard deviation. It may also be used to determine the step size

for future staircase testing of the subject chain model.

Annex B

(informative)

Combined test method (CTM)

The purpose of the combined test method (hereinafter referred to as CTM) is to

determine the slope of the F-N line and the fatigue limit of a particular chain in a single

test series. The CTM also may be used to determine the step size for future staircase

testing.

Annex C

(informative)

Justification for adding one step to fatigue limit in staircase analysis

The staircase analyses in this Standard utilize all test points, both failures and run-outs.

The calculated minimum fatigue strength (Fb-3S) is always less than the lowest test

force. By definition, all responses at the lowest test force must be run-outs.

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