This document specifies the fundamental formulae for use in the determination of the surface load capacity of cylindrical gears with involute external or internal teeth. It includes formulae for all influences on surface durability for which quantitative assessments can be made. It applies primarily to oil\u2011lubricated transmissions, but can also be used to obtain approximate values for (slow\u2011running) grease\u2011lubricated transmissions, as long as sufficient lubricant is present in the mesh at all times.<\/p>\n
The given formulae are valid for cylindrical gears with tooth profiles in accordance with the basic rack standardized in ISO 53. They can also be used for teeth conjugate to other basic racks where the actual transverse contact ratio is less than \u03b5\u03b1<\/sub><\/i>n<\/sub> = 2,5. The results are in good agreement with other methods (see References [5], [7], [10], [12]).<\/p>\n These formulae cannot be directly applied for the assessment of types of gear tooth surface damage such as plastic yielding, scratching, scuffing and so on, other than that described in Clause 4.<\/p>\n The load capacity determined by way of the permissible contact stress is called the \u201csurface load capacity\u201d or \u201csurface durability\u201d.<\/p>\n If this scope does not apply, refer to ISO 6336\u20111:2019, Clause 4.<\/p>\n Calculation of load capacity of spur and helical gears – Calculation of surface durability (pitting)<\/b><\/p>\nPDF Catalog<\/h4>\n
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\n PDF Pages<\/th>\n PDF Title<\/th>\n<\/tr>\n \n 2<\/td>\n undefined <\/td>\n<\/tr>\n \n 7<\/td>\n Foreword <\/td>\n<\/tr>\n \n 8<\/td>\n Introduction <\/td>\n<\/tr>\n \n 11<\/td>\n 1 Scope
2 Normative references <\/td>\n<\/tr>\n\n 12<\/td>\n 3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
3.2 Symbols and abbreviated terms <\/td>\n<\/tr>\n\n 16<\/td>\n 4 Pitting damage and safety factors <\/td>\n<\/tr>\n \n 17<\/td>\n 5 Basic formulae
5.1 General <\/td>\n<\/tr>\n\n 18<\/td>\n 5.2 Safety factor for surface durability (against pitting), SH
5.3 Contact stress, \u03c3H <\/td>\n<\/tr>\n\n 19<\/td>\n 5.4 Permissible contact stress, \u03c3HP
5.4.1 General <\/td>\n<\/tr>\n\n 20<\/td>\n 5.4.2 Determination of permissible contact stress, \u03c3HP \u2014 Principles, assumptions and application
5.4.3 Permissible contact stress, \u03c3HP: Method B <\/td>\n<\/tr>\n\n 21<\/td>\n 5.4.4 Permissible contact stress for limited and long life: Method B <\/td>\n<\/tr>\n \n 23<\/td>\n 6 Zone factor, ZH, and contact factors, ZB and ZD
6.1 General <\/td>\n<\/tr>\n\n 24<\/td>\n 6.2 Zone factor, ZH
6.2.1 General
6.2.2 Graphical values
6.2.3 Determination by calculation
6.3 Contact factors, ZB and ZD, for \u03b5\u03b1 \u2264 2 <\/td>\n<\/tr>\n\n 27<\/td>\n 6.4 Contact factors, ZB and ZD, for \u03b5\u03b1 > 2
7 Elasticity factor, ZE <\/td>\n<\/tr>\n\n 28<\/td>\n 8 Contact ratio factor, Z\u03b5
8.1 General
8.2 Determination of contact ratio factor, Z\u03b5
8.2.1 Graphical values <\/td>\n<\/tr>\n\n 29<\/td>\n 8.2.2 Determination by calculation <\/td>\n<\/tr>\n \n 30<\/td>\n 8.3 Calculation of transverse contact ratio, \u03b5\u03b1, and overlap ratio, \u03b5\u03b2
8.3.1 Transverse contact ratio, \u03b5\u03b1
8.3.2 Overlap ratio, \u03b5\u03b2 <\/td>\n<\/tr>\n\n 31<\/td>\n 9 Helix angle factor, Z\u03b2
10 Strength for contact stress
10.1 General
10.2 Allowable stress numbers (contact), \u03c3H lim: Method B <\/td>\n<\/tr>\n\n 32<\/td>\n 10.3 Allowable stress number values: Method BR
11 Life factor, ZNT (for flanks)
11.1 General
11.2 Life factor, ZNT: Method A
11.3 Life factor, ZNT: Method B <\/td>\n<\/tr>\n\n 34<\/td>\n 12 Influence of lubricant film, factors ZL, Zv and ZR
12.1 General
12.2 Influence of lubricant film: Method A
12.3 Influence of lubricant film, factors ZL, Zv and ZR: Method B
12.3.1 General <\/td>\n<\/tr>\n\n 35<\/td>\n 12.3.2 Factors ZL, Zv and ZR for reference stress <\/td>\n<\/tr>\n \n 40<\/td>\n 12.3.3 Factors ZL, Zv and ZR for static stress
13 Work hardening factor, ZW
13.1 General
13.2 Work hardening factor, ZW: Method A <\/td>\n<\/tr>\n\n 41<\/td>\n 13.3 Work hardening factor, ZW: Method B
13.3.1 Surface-hardened steel pinion with through-hardened steel gear <\/td>\n<\/tr>\n\n 43<\/td>\n 13.3.2 Through-hardened steel pinion with through-hardened steel gear <\/td>\n<\/tr>\n \n 44<\/td>\n 13.3.3 Surface-hardened steel pinion with ductile iron gear <\/td>\n<\/tr>\n \n 46<\/td>\n 14 Size factor, ZX <\/td>\n<\/tr>\n \n 47<\/td>\n Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" \n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n BSI<\/b><\/a><\/td>\n 2020<\/td>\n 48<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":362871,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2641],"product_tag":[],"class_list":{"0":"post-362861","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-bsi","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/362861","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/362871"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=362861"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=362861"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=362861"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}