Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)

The durability of a hybrid ceramic 25-mm-bore ball bearing having a single outer land-guided retainer was evaluated and improved in liquid hydrogen at speeds up to 120,000 rpm (120,000 min-1) (3 million DN) by comparing the propagation of superficial thermal microcracks on Si3N4 balls at various spe...

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Autores principales:	Masataka Nosaka, Satoshi Takada, Makoto Yoshida, Masataka Kikuchi, Takayuki Sudo, Shohei Nakamura
Formato:	article
Lenguaje:	EN
Publicado:	Japanese Society of Tribologists 2010
Materias:	cryogenic tribology solid-lubrication ball bearing hybrid ceramic bearing si3n4 ball thermal shock crush load thermal cracks jet cooling bearing acceleration Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/1c5118125fa74da89a8231a6d5a0ff69
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spelling	oai:doaj.org-article:1c5118125fa74da89a8231a6d5a0ff692021-11-05T09:27:18ZImprovement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)1881-219810.2474/trol.5.60https://doaj.org/article/1c5118125fa74da89a8231a6d5a0ff692010-02-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/trol/5/1/5_1_60/_pdf/-char/enhttps://doaj.org/toc/1881-2198The durability of a hybrid ceramic 25-mm-bore ball bearing having a single outer land-guided retainer was evaluated and improved in liquid hydrogen at speeds up to 120,000 rpm (120,000 min-1) (3 million DN) by comparing the propagation of superficial thermal microcracks on Si3N4 balls at various speeds. To select a tough Si3N4 ball capable of restraining crack propagation, bearing tests were conducted for three kinds of the Si3N4 balls with different jet-cooling systems. The test results showed that the Si3N4 ball having high fracture toughness as well as high thermal shock resistance could restrain the propagation of wide-ditch microcracks. With regard to the jet-cooling system, four nozzles were better than two nozzles with increasing jet speed. Furthermore, the jet flow aimed at the retainer was superior to that aimed at the inner race, and its result indicated that microcracks might be generated at the trace in contact with the outer raceway under insufficient cooling conditions with a large centrifugal force. Thus, decreasing the maximum contact stress of the outer race to 2.0 GPa by a limited race curvature of 0.51 could restrain the propagation of superficial microcracks.Masataka NosakaSatoshi TakadaMakoto YoshidaMasataka KikuchiTakayuki SudoShohei NakamuraJapanese Society of Tribologistsarticlecryogenic tribologysolid-lubricationball bearinghybrid ceramic bearingsi3n4 ballthermal shockcrush loadthermal cracksjet coolingbearing accelerationPhysicsQC1-999Engineering (General). Civil engineering (General)TA1-2040Mechanical engineering and machineryTJ1-1570ChemistryQD1-999ENTribology Online, Vol 5, Iss 1, Pp 60-70 (2010)
institution	DOAJ
collection	DOAJ
language	EN
topic	cryogenic tribology solid-lubrication ball bearing hybrid ceramic bearing si3n4 ball thermal shock crush load thermal cracks jet cooling bearing acceleration Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999
spellingShingle	cryogenic tribology solid-lubrication ball bearing hybrid ceramic bearing si3n4 ball thermal shock crush load thermal cracks jet cooling bearing acceleration Physics QC1-999 Engineering (General). Civil engineering (General) TA1-2040 Mechanical engineering and machinery TJ1-1570 Chemistry QD1-999 Masataka Nosaka Satoshi Takada Makoto Yoshida Masataka Kikuchi Takayuki Sudo Shohei Nakamura Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
description	The durability of a hybrid ceramic 25-mm-bore ball bearing having a single outer land-guided retainer was evaluated and improved in liquid hydrogen at speeds up to 120,000 rpm (120,000 min-1) (3 million DN) by comparing the propagation of superficial thermal microcracks on Si3N4 balls at various speeds. To select a tough Si3N4 ball capable of restraining crack propagation, bearing tests were conducted for three kinds of the Si3N4 balls with different jet-cooling systems. The test results showed that the Si3N4 ball having high fracture toughness as well as high thermal shock resistance could restrain the propagation of wide-ditch microcracks. With regard to the jet-cooling system, four nozzles were better than two nozzles with increasing jet speed. Furthermore, the jet flow aimed at the retainer was superior to that aimed at the inner race, and its result indicated that microcracks might be generated at the trace in contact with the outer raceway under insufficient cooling conditions with a large centrifugal force. Thus, decreasing the maximum contact stress of the outer race to 2.0 GPa by a limited race curvature of 0.51 could restrain the propagation of superficial microcracks.
format	article
author	Masataka Nosaka Satoshi Takada Makoto Yoshida Masataka Kikuchi Takayuki Sudo Shohei Nakamura
author_facet	Masataka Nosaka Satoshi Takada Makoto Yoshida Masataka Kikuchi Takayuki Sudo Shohei Nakamura
author_sort	Masataka Nosaka
title	Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
title_short	Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
title_full	Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
title_fullStr	Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
title_full_unstemmed	Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)
title_sort	improvement of durability of hybrid ceramic ball bearings in liquid hydrogen at 3 million dn (120,000 rpm)
publisher	Japanese Society of Tribologists
publishDate	2010
url	https://doaj.org/article/1c5118125fa74da89a8231a6d5a0ff69
work_keys_str_mv	AT masatakanosaka improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm AT satoshitakada improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm AT makotoyoshida improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm AT masatakakikuchi improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm AT takayukisudo improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm AT shoheinakamura improvementofdurabilityofhybridceramicballbearingsinliquidhydrogenat3milliondn120000rpm
_version_	1718444333982547968

Improvement of Durability of Hybrid Ceramic Ball Bearings in Liquid Hydrogen at 3 Million DN (120,000 rpm)

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