Tribo-Characteristics of Cryogenic Hybrid Ceramic Ball Bearings for Rocket Turbopumps: Self-Lubricating Performance©
1997; Taylor & Francis; Volume: 40; Issue: 1 Linguagem: Inglês
10.1080/10402009708983624
ISSN1547-397X
AutoresMasataka Nosaka, Mamoru Oike, Masataka Kikuchi, Tohru Mayumi,
Tópico(s)Space Exploration and Technology
ResumoExperiments were conducted to investigate and compare the self-lubricating performance of two types of modified, 25 mm-bore ball bearings: a hybrid bearing with Si3N4 ceramic balls, and an all-steel bearing. The modified bearings had a single outer land-guided retainer with elliptical pockets and a narrow axial pocket clearance to reduce wobbling of the retainer. The bearings were tested under high thrust loads to 2840 N and at speeds up to 50,000 rpm in liquid hydrogen (LH2), liquid oxygen (LO2), or liquid nitrogen (LN2). Testing showed that the bearing torque of the modified all-steel bearing was drastically decreased to about one-half that of the conventional double outer land-guided bearing at a speed of 50,000 rpm in LH2 Furthermore, the hybrid bearing had relatively stable variation of bearing torque and better load capacity than those of the all-steel bearing in both LH2 and NH2. However, in LO2, the all-steel bearing exhibited excellent performance with high load capacity at high speeds, contrasted with poor self-lubrication by the hybrid bearing.
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