SH/T 0326-1992 Determination of leakage of lubricating grease for automotive wheel bearings

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0326-92
• Chinese name: Determination of leakage of lubricating grease for automotive wheel bearings
• English name: not provided in the available source (the supplementary notes mention reference adoption of ASTM D 1263-86)
• Replacement relationship: replaces ZB E36 023-89
• Reference adoption: ASTM D 1263-86 "Determination of leakage of lubricating grease for automotive wheel bearings"
• Approval/implementation: approved by China Petrochemical Corporation 1992-05-20, implemented on 1992-05-20

2. Scope of application and non-applicability

• Applicable: determination of leakage of automotive wheel bearing lubricating grease under laboratory test conditions; can be used to distinguish products with obviously different leakage characteristics; is the main means for screening and evaluating the leakage performance of lubricating grease.
• Not applicable/limitations: the magnitude of the measured result cannot indicate the length of the actual service life of the lubricating grease, nor can it be used to distinguish products with similar leakage.

3. Method principle

Place the sample into a modified front wheel hub and axle assembly; the hub rotates at a speed of 660±30 r/min, and the axle gradually heats up and is maintained at 104.5±1.5 ℃, operating for a total of 360±5 min. Determine the leakage of lubricating grease or oil (or both), and at the end of the test observe the bearing surface condition.

4. Reagents and materials (purity / preparation)

4.1 Reagents

• 4.1.1 n-Heptane: chemically pure; the washing solvent that must be selected for arbitration testing.
• 4.1.2 Petroleum ether: 90～120 ℃, analytically pure.

4.2 Materials

• Rubber industry solvent naphtha.

5. Apparatus and equipment

• 5.1 Wheel bearing grease leakage testing machine: as shown in Figure 1, detailed description see Appendix A. The testing machine consists of a dedicated front wheel hub and axle assembly; the hub is driven by a motor through a V-shaped belt. The assembly is installed in a constant-temperature box, and the box is equipped with devices for measuring the ambient temperature inside the box and the axle temperature. A torque wrench suitable for hex nuts of size 31.75 mm is also required.
• 5.2 Thermometer: meets the requirements of clause 3.8 in GB/T 6536 for a low-temperature-range thermometer −2～300 ℃ (requires confirmation against the source standard (source-text extraction): the original text is "[unreadable sign]2～300C", suspected to be "−2～300 ℃").
• Figure 1 schematic diagram labels of the testing machine (source-text extraction excerpt, requires confirmation against the source standard (source-text extraction)): 1— motor, speed 1750±25 r/min; 2— motor shaft seal; 3— motor extension; 4— fan; 5— liquid transmission type temperature control bulb; 6— box cover frame; 7— driving pulley, outer diameter 81.3 mm; 8—V-shaped belt; 9— thermostat; 10— motor switch; 11— control heater switch; 12— auxiliary heater switch; 13— indicator light; 14— driven pulley, outer diameter 213 mm; 15— hub and axle assembly; 16— spindle thermometer; 17— thermometer insertion hole about 19.1 mm.
• Appendix A Equipment (supplementary element):
  • A1 Main assembly: consists of a dedicated front wheel hub and axle assembly, and is installed in a controllable constant-temperature box; the hub is driven by a motor through a V-shaped belt, with the structure shown in Figure 1. Two heaters are installed on the base of the instrument, one is the control heater and the other is the auxiliary heater, and constant temperature control is possible. Note: It is specified that all new testing machines should use a liquid expansion type temperature regulator, and the position of its bulb is shown in Figure 1. Other types of temperature regulators that can maintain the specified temperature and positioning may also be used. Thermocouples may be used to measure the ambient (inside the box) and axle temperatures, or a low-temperature mercury glass thermometer, rod type, meeting the thermometer requirements of clause 5.2 of this standard may also be used.
  • A2 Bearing spindle: the spindle structure is shown in Figure A1.
  • A3 Bearing hub: the bearing hub structure is shown in Figure A2.
  • A4 Leakage receiver: the leakage receiver is used to collect the lubricating grease leaking from the inner end of the hub, and its structure is shown in Figure A3. This receiver is detachable so as to determine the loss of lubricating grease; it is fitted on the axle and fixed at the place against the large bearing. Note: Because accelerated leakage is desired during laboratory testing, ordinary grease retainers cannot be used, and in actual use retainers are also often found to be defective.
  • A5 Fan: the fan structure is shown in Figure A4.

6. Recommended operating conditions

• Speed: 660±30 r/min.
• Box temperature: 113±3 ℃ (before the temperature inside the box rises to 113 ℃, the auxiliary heater may be used).
• Axle temperature: 104.5±1.5 ℃.
• Operating time: total 360±5 min.
• Heating time requirements: use a temperature regulator or constant-temperature device to make the box temperature reach 113±3 ℃ within 15±5 min; and make the axle temperature reach 104.5±1.5 ℃ within 60±10 min, and continue operating for 300±15 min until the end of the test.
• Heater power: the testing machine is equipped with a heater of 660 W (Note: the heat it generates can generally reach the required temperature within the specified time. If it is found that the requirement cannot be met, it should be replaced with a heater of the required power. Ventilation can affect the heating speed, so attention should be paid to the placement position of the testing machine).
• Grounding requirement: the instrument (axle, box, and motor) must be grounded; otherwise, due to accumulated static electricity, the thermocouple may fail to function. Instrument grounding is shown in Figure 1.

7. Sampling and sample preparation

• 6.1 Weigh 90±1 g of lubricating grease sample on a flat plate; use a scraper to load 2±0.1 g of sample into the small bearing and 3±0.1 g of sample into the large bearing; evenly coat the remaining sample (85 g) inside the hub, and coat a thin layer of sample on the bearing outer ring inside the hub.
  • Note ①: It is more suitable to use a narrow wedge-shaped scraper to pack the sample into the bearing.
  • Note ②: In practice, the remaining sample will fill the hub and even the outer ring; except for samples with very strong fibrous properties, a scraper 150 mm long can be used to spread the sample evenly very easily.
• 6.2 Weigh the leakage receiver and hub cover separately, accurate to 0.1 g; install the leakage receiver and the large (inner) bearing at the appropriate position on the axle; install the hub and the small (outer) bearing onto the axle, then install the loose-fitting retainer ring. Use a torque wrench to tighten the hex nut fixing the hub assembly with a torque of 6.8±0.1 N·m, then back off the hex nut by 60°±5 (or one flat of the nut), and then lock it in that position with the second nut. Screw on the hub cover, install the V-shaped belt on the pulleys, and then put on the box cover.
  • Note ①: Users without a balance with a scale interval of 0.1 g may choose a balance with a scale interval of 0.5 g for weighing. For arbitration testing, a balance with a scale interval of 0.1 g must be used for weighing.
  • Note ②: The leakage receiver should be carefully checked to ensure that the inner edge is flush with the sealing surface; otherwise, this edge will hinder the correct positioning of the inner bearing.
  • Note ③: When assembling the hub filled with sample onto the axle, prevent the sample from contacting the axle.
  • Note ④: Frequently check the driving pulley and driven pulley to keep them aligned in one plane; otherwise, leakage will change.
  • Note ⑤: Excessive end play of the hub assembly is sometimes caused by bearing wear; therefore, after every 250 tests, or when inspection reveals bearing wear or other damage, new bearings should be replaced. The inner ring number of the large (inner) bearing is Timken (Timken) 15118, and the corresponding outer ring number is 15250. The inner ring number of the small (outer) bearing is Timken (Timken) 09074, and the corresponding outer ring number is 09196.

8. Analytical procedure

• 6.3 After putting on the box cover, turn on the motor and the two sets of heaters, with a speed of 660±30 r/min. Use a temperature regulator or constant-temperature device to make the box temperature reach 113±3 ℃ within 15±5 min (before the temperature inside the box rises to 113 ℃, the auxiliary heater may be used) and make the axle temperature reach 104.5±1.5 ℃ within 60±10 min, and continue operating for 300±15 min until the end of the test. Total operation 360±5 min.
• 6.4 At the end of the 360 min test period (counted from when the motor and heaters are turned on), turn off the power and disassemble the instrument while hot (wear suitable protective equipment).
• 6.5 After the instrument has cooled, weigh the leakage receiver and hub cover separately, accurate to 0.1 g.
  • Note: If the leakage receiver overflows, the overflowed lubricating grease or oil (or both) should be weighed and included in the recorded total leakage.
• 6.6 Soak the two bearings in n-heptane (petroleum ether or solvent naphtha) at room temperature for 2 min to remove the sample. Carefully inspect the bearing surfaces for varnish, gum, or lacquer-like deposits.
  • Note: It has been found that some soaps in wheel bearing lubricating grease cannot be completely washed off the bearings with solvent; therefore, a soap film may remain on the bearings. This film is easily distinguished from varnish, gum, or lacquer-like deposits produced by deterioration of the lubricant.

9. Qualitative and quantitative determination and calculation formula

The total leakage of the sample is expressed as X (g), and is calculated according to the following formula:

X = (m₂ − m₁) + (m₄ − m₃)

Where:

• m₂——mass of leakage receiver and grease after the test, g;
• m₁——mass of leakage receiver before the test, g;
• m₄——mass of hub cover and grease after the test, g;
• m₃——mass of hub cover before the test, g.

(requires confirmation against the source standard (source-text extraction): the original formula and symbol subscripts contain source-text extraction noise, such as "m [unreadable sign]m" "m [unreadable sign]ms" "m" "ms", etc.; they have been organized according to context, and verification against the formal text is recommended.)

10. Precision

Judge the reliability of the test results according to the following provisions (95% confidence level).

• 8.1 Repeatability: the difference between two results obtained by the same operator from repeated determinations shall not exceed the following values.
  • Leakage amount range ≤2 g: repeatability 1.5 g (requires confirmation against the source standard (source-text extraction): the original table layout is garbled, and the correspondence of values requires verification)
  • Leakage amount range 15～20 g: repeatability 9 g (requires confirmation against the source standard (source-text extraction))
• 8.2 Reproducibility: the difference between two results submitted by different laboratories shall not exceed the following values.
  • Leakage amount range ≤2 g: reproducibility 4 g (requires confirmation against the source standard (source-text extraction))
  • Leakage amount range 15～20 g: reproducibility 9 g (requires confirmation against the source standard (source-text extraction))
• Note: the precision for other leakage amount ranges has not been determined.

11. Report

• 9.1 Take the arithmetic mean of two results from repeated determinations as the test result.
• 9.2 Report any deposits of paint film, gum, or varnish-like material adhering to the bearing surface.

12. Referenced documents

• GB/T 6536 Distillation test method for petroleum products

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick reference for questions and answers