GB/T 24607-2023Rolling bearings—Test and assessment for life and reliability (English PDF)

3.1 Test for life

A test conducted to estimate or verify product life.

3.2 Test for reliability

A test conducted to measure, evaluate, analyze and improve product reliability levels.

3.3 Failures of rolling bearing

Rolling bearings are unable to meet predetermined design performance requirements due to defects or damage.

3.4 Figure estimation

A method of parameter estimation with the help of Weibull probability plots.

3.5 Best liner invariant estimation

A numerical calculation method that uses tables to estimate parameters using the best linear invariant estimate.

3.6 Sequential method

A method of analyzing and judging test data one by one based on sequential tests.

7.1 General requirements

7.1.1 The test equipment shall be a bearing life testing machine whose performance parameters can meet the usage requirements or performance assessment capabilities and which have been regularly calibrated. The test equipment shall have some necessary monitoring means during the test process, such as monitoring of rotation speed, load, temperature, vibration, lubrication and other parameters.

7.1.2 The same batch of bearing samples shall be tested on testing equipment with the same main structure and performance parameters.

7.2 Tolerance zone requirements for test spindles and bearing housing holes that fit with bearings

7.2.1 When the inner ring of the bearing rotates and the outer ring is fixed, the tolerance zone of the test spindle and the bearing seat hole that matches the bearing is recommended to be selected according to Table 1.

7.2.2 When the bearing is subjected to a large radial load, the interference between the inner ring of the bearing and the test spindle shall be appropriately increased while ensuring the working clearance of the bearing to prevent relative sliding between the inner ring of the bearing and the test spindle during operation.

7.2.3 For bearings operating in other ways, the fit shall be determined through consultation with the user.

8.1 Sampling

During sampling inspection, bearing samples shall be randomly selected from the finished products that pass the inspection.

8.2 Sample size

The recommended test sample size is 8 to 20 sets. Also prepare 5 to 10 sets of spare samples.

8.3 Sample serial number

Bearing samples shall have clearly identifiable unique identification.

9.1 General requirements

The test conditions can be formulated according to the bearing parameters or the bearing operating conditions. When formulating test conditions, the effects of temperature, bearing contact stress, spindle deflection and other factors on the bearing need to be considered. For conventional bearing tests, when circulating oil lubrication is used, the bearing outer ring temperature shall not exceed 95°C.

9.2 Test speed

When the inner ring of the bearing rotates, the test speed is generally 20% ~ 60% of the bearing's limit speed. When the user has needs, it can be determined through consultation with the user.

9.3 Test load

9.3.1 General

The bearing test load can be selected based on the equivalent dynamic load. The equivalent dynamic load P generally takes 20%~35% of the basic rated dynamic load C. Usually refer to the test speed.

9.3.2 Equivalent dynamic load calculation

The equivalent dynamic load calculation is divided into the following three situations.

9.4 Bearing lubrication

9.4.1 Oil lubrication

9.4.1.1 Lubricant designation

The lubricating oil shall be L-HM32 hydraulic oil that complies with GB 11118.1-2011.

When the test load is large and the test temperature is high, hydraulic oil with a higher viscosity grade can be selected, such as L-HM46, L-HM68, etc. The circulating lubricating oil for special testing (including additives added to the oil, etc.) shall be determined in consultation with the user.

9.4.1.2 Lubricating oil quality control

The test lubricating oil meets the following requirements. […]

9.4.2 Grease lubrication

9.4.2.1 When testing grease-lubricated bearings, the lubricating oil circuit of the test bearing shall be closed.

9.4.2.2 The grease used for testing open grease-lubricated bearings shall be determined in consultation with the user. During the test process, the bearing temperature changes shall be monitored and the grease loss shall be checked. Add grease when necessary to avoid affecting the lubrication effect.

10.1 Test preparation

10.1.1 Pre-installation inspection

Before the test, the number and size of the main parts of the test shall be reviewed and inspected to ensure that there is no interference between the parts. Review and inspect the dimensions of the test spindle and bearing seat holes that match the inner and outer rings of the bearing to ensure that they meet the technical requirements of relevant drawings and documents.

10.1.2 Installation

10.1.2.1 Installation of bearing inner ring and test spindle

The installation of the bearing inner ring and the test spindle generally uses press mounting, but hot mounting can also be used. The heating temperature of sealed bearings generally does not exceed 80°C. The heating temperature of open bearings generally does not exceed 100°C. The installation force shall not be transmitted through the rolling elements during installation.

10.1.2.2 Installation of bearing outer ring and bearing seat hole

To install the bearing outer ring and the bearing seat hole, push the bearing gently and install it in place.

10.2 Test equipment debugging and calibration

10.2.1 After the test body and the test equipment are assembled, rotate the test spindle.

10.3 Running-in test

For oil lubricated bearing testing, the lubricating oil circuit shall be opened and the test bearing shall be fully lubricated. Oil-lubricated or grease-lubricated bearings shall first apply a small amount of load, and then start the testing machine to start the bearing.

When applying combined loads, the axial load shall be applied first and then the radial load. Under normal circumstances, the load and speed shall be slowly increased to the set value within 3 h. When the test load is large or the temperature rise changes rapidly, the running-in time shall be appropriately extended. Generally, it is no more than 24 h.

10.4 Formal test

After the running-in test, conduct the formal test. Record the monitoring data and test time during the test. The rotation speed, load and temperature shall be controlled within the required range.

10.5 Data collection

Sample failure during the test due to reasons other than the bearing itself (such as equipment reasons, human reasons, accidents, etc.) shall not be included in the normal failure data.

10.6 Termination of test

The test shall be stopped when the test reaches the predetermined time or the bearing fails.

10.7 Inspection after test

After the test is completed, the sample shall be inspected to determine whether the sample has rejected. If necessary, the cause analysis of typical failure samples can be carried out in the test report. Failures include.

10.8 Test sample processing

Bearing samples after testing shall be properly stored. Take photos of rejected samples and their failure morphology for storage. […]