Study on rating life and frictional wear characteristics in the high temperature of the ceramic ball bearings
Grant-in-Aid for Scientific Research (C)
|Allocation Type||Single-year Grants |
Materials/Mechanics of materials
|Research Institution||Institute of technologists (2002-2003)|
Takushoku University (2001)
ICHIKAWA Shigeki Institute of technologists, Department of Manufacturing Technologists, Assistant professor, 技能工芸学部・製造技能工芸学科, 助教授 (80193431)
|Project Period (FY)
2001 – 2003
Completed (Fiscal Year 2003)
|Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥2,400,000 (Direct Cost: ¥2,400,000)
|Keywords||Basic load rating / Ceramic ball bearings / Staircase method / Weibull method / Fatigue life / Wear life / 14S-N testing method / 高温特性 / ワイブル法 / 14S-N試験法 / S-N試験法 / 寿命試験 / 高温寿命 / 14-SN 試験法|
In the atmosphere of high-temperature 200℃, frictional wear characteristics and rating life of the ceramic ball bearings were obtained. By changing conventional Weibull method, the lifetest of the ceramic ball bearings was carried out using stairecase method which was one of the fatigue test method. The similar test was also carried out and was compared on steel ball bearings and stainless steel ball bearings of the marketing. The result is shown in the following.
1. The steel ball bearings in lubricating at high temperature 200℃ comes to the life of the abrasion. About 70% is the fracture by the flaking on the stainless steel ball bearings, and then, 30% of the remainder is the wear life. In case of the ceramic ball bearings, 50% of bearing element parts is fractured in the flaking, and 50% of the remainder is the wear life.
2. In the unlubricating condition, the bearing mainly comes to the life by the abrasion. This is not based on the type of the ball bearings. Surface roughness of ra
ceways is made to deteriorate by generated abrasion powder. As the result, it is a cause that the ball bearings is damaged with large vibration.
3. The basic load rating of the ceramic ball bearings in lubricating at high-temperature 200℃ is small with 1/1.84 times of the steel ball bearings of the equal condition. The basic load rating of the ceramic ball bearings becomes 1.46 times further than basic load rating of the stainless steel ball bearings at 200℃ in case of the unlubricating condition, and it is excellent in the high temperature property.
4. The slope of the 14S-N testing method is tested in staircase method in which the initial condition is not determined. Next, average load and standard deviation were obtained using the approximate curve of the slope. The average load was made to be the first test load, and the standard deviation was made to be the step size. These values are made to be an initial conditions in the staircase method. It was possible to carry out the staircase method from the preliminary experiment of 14S-N testing method, when there is no load data which becomes a reference like the unlubricating condition in high temperature even in.
5. Estimation average and estimation standard deviation in numbers of samples of 20 were calculated by the consideration of the labor spent with number of samples which can be prepared for the test. However, it is necessary to calculate the accuracy of large sample size, when that there are small data as a reference is considered. Expectation values of estimation average and estimation standard deviation newly calculated numbers of samples of 24. As the result, expectation value of standard deviation is improved from 0.8σ at 0.9σ accuracy, when number of samples are increased from 20 in 24. Less
Report (4 results)
Research Products (14 results)