{"id":357031,"date":"2024-10-20T01:15:01","date_gmt":"2024-10-20T01:15:01","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bsi-pd-iso-ts-145212020\/"},"modified":"2024-10-26T01:40:52","modified_gmt":"2024-10-26T01:40:52","slug":"bsi-pd-iso-ts-145212020","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bsi-pd-iso-ts-145212020\/","title":{"rendered":"BSI PD ISO\/TS 14521:2020"},"content":{"rendered":"

This document specifies formulae for calculating the load capacity of cylindrical worm gears and covers load ratings associated with wear, pitting, worm deflection, tooth breakage and temperature. Scuffing and other failure modes are not covered by this document.<\/p>\n

The load rating and design procedures are only valid for tooth surface sliding velocities, , less than or equal to 25 m\/s and contact ratios greater than 2,1. For wear, load rating and design procedures are only valid for tooth surface sliding velocities which are above 0,1 m\/s. The rules and recommendations for the dimensioning, lubricants or materials selected by this document only apply to centre distances of 50 mm and larger. For centre distances below 50 mm, method A applies.<\/p>\n

The choice of appropriate methods of calculation requires knowledge and experience. This document is intended for use by experienced gear designers who can make informed judgements concerning factors. It is not intended for use by engineers who lack the necessary experience. See 4.7<\/span>.<\/p>\n

\n
\n WARNING\n <\/div>\n

The geometry of worm gears is complex, therefore the user of this document is encouraged to make sure that a valid working geometry has been established.<\/p>\n<\/div>\n

PDF Catalog<\/h4>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
PDF Pages<\/th>\nPDF Title<\/th>\n<\/tr>\n
2<\/td>\nundefined <\/td>\n<\/tr>\n
8<\/td>\nForeword <\/td>\n<\/tr>\n
9<\/td>\nIntroduction <\/td>\n<\/tr>\n
11<\/td>\n1 Scope
2 Normative references
3 Terms, definitions and symbols
3.1 Terms and definitions <\/td>\n<\/tr>\n
12<\/td>\n3.2 Symbols <\/td>\n<\/tr>\n
17<\/td>\n4 General consideration
4.1 Worm gear load capacity rating criteria <\/td>\n<\/tr>\n
18<\/td>\n4.2 Basis of the method
4.3 Concept of absolute and relative parameters <\/td>\n<\/tr>\n
19<\/td>\n4.4 Applicability <\/td>\n<\/tr>\n
20<\/td>\n4.5 Validity <\/td>\n<\/tr>\n
21<\/td>\n4.6 System considerations
4.7 Calculation methods A, B, C
4.7.1 Generality on methods A, B and C <\/td>\n<\/tr>\n
22<\/td>\n4.7.2 Notes on numerical formulae
4.7.3 Base conditions, interaction <\/td>\n<\/tr>\n
23<\/td>\n4.7.4 Other notes
4.8 Standard reference gear
5 Required date for calculation
5.1 Input variable <\/td>\n<\/tr>\n
25<\/td>\n5.2 Safety factors
6 Forces, speeds and parameters for the calculation of stresses
6.1 General
6.2 Tooth forces
6.2.1 Application factor
6.2.2 Dynamic factor
6.2.3 Load distribution factor <\/td>\n<\/tr>\n
26<\/td>\n6.2.4 Tooth force components <\/td>\n<\/tr>\n
27<\/td>\n6.3 Sliding velocity at reference diameter
6.4 Physical parameters
6.4.1 Generality on physical parameters <\/td>\n<\/tr>\n
28<\/td>\n6.4.2 Parameter for the mean Hertzian stress <\/td>\n<\/tr>\n
29<\/td>\n6.4.3 Parameter for the mean lubricant film thickness <\/td>\n<\/tr>\n
30<\/td>\n6.4.4 Parameter for the mean sliding path <\/td>\n<\/tr>\n
31<\/td>\n6.5 Calculation of mean contact stress <\/td>\n<\/tr>\n
32<\/td>\n6.6 Calculation of mean lubricant film thickness <\/td>\n<\/tr>\n
33<\/td>\n6.7 Calculation of the wear path
6.8 Calculation of the lubricant kinematic viscosity
7 Efficiency and power loss
7.1 General <\/td>\n<\/tr>\n
34<\/td>\n7.2 Total efficiency
7.2.1 Method A
7.2.2 Method B
7.3 Total power loss
7.3.1 Methods of calculation <\/td>\n<\/tr>\n
35<\/td>\n7.3.2 Idle running power loss
7.3.3 Bearing load power loss
7.3.4 Sealing power loss <\/td>\n<\/tr>\n
36<\/td>\n7.3.5 Adaptation of the calculation procedure to a specific test
7.4 Gear efficiency
7.4.1 Efficiency calculation
7.4.2 Base coefficient of friction, \u00b5OT, of the standard reference gear <\/td>\n<\/tr>\n
38<\/td>\n7.4.3 Size factor <\/td>\n<\/tr>\n
39<\/td>\n7.4.4 Geometry factor
7.4.5 Material factor
7.4.6 Roughness factor
7.4.7 Adaptation of the calculation procedure to a specific test <\/td>\n<\/tr>\n
40<\/td>\n7.5 Meshing power loss
7.5.1 Method A
7.5.2 Method B
7.5.3 Method C
8 Wear load capacity
8.1 General
8.2 Wear safety factor <\/td>\n<\/tr>\n
41<\/td>\n8.3 Expected wear
8.3.1 Method A
8.3.2 Methods B, C <\/td>\n<\/tr>\n
45<\/td>\n8.4 Permissible wear <\/td>\n<\/tr>\n
46<\/td>\n8.5 Adaptation of the calculation procedure to a specific test
9 Surface durability (pitting resistance)
9.1 General
9.2 Pitting safety factor <\/td>\n<\/tr>\n
47<\/td>\n9.3 Actual contact stress
9.3.1 Method A
9.3.2 Methods B, C
9.4 Limiting value of contact stress <\/td>\n<\/tr>\n
48<\/td>\n9.5 Adaptation of the calculation procedure to specific test
10 Deflection
10.1 General <\/td>\n<\/tr>\n
49<\/td>\n10.2 Deflection safety factor
10.3 Actual deflection
10.3.1 Method A
10.3.2 Method B
10.3.3 Method C <\/td>\n<\/tr>\n
50<\/td>\n10.4 Limiting value of deflection
11 Tooth root strength
11.1 Safety factor for tooth breakage
11.2 Actual tooth root stress
11.2.1 Method A
11.2.2 Method B
11.2.3 Method C <\/td>\n<\/tr>\n
52<\/td>\n11.3 Limiting value of shear stress at tooth root
11.3.1 General
11.3.2 Shear endurance limit, \u03c4F lim T
11.3.3 Life factor, YNL <\/td>\n<\/tr>\n
54<\/td>\n11.4 Adaptation of the calculation procedure to a specific test
12 Temperature safety factor
12.1 Temperature safety factor for splash lubrication
12.1.1 General <\/td>\n<\/tr>\n
55<\/td>\n12.1.2 Determination of oil sump temperature <\/td>\n<\/tr>\n
56<\/td>\n12.1.3 Limiting values
12.2 Temperature safety factor for oil spray lubrication
12.2.1 General
12.2.2 Cooling capacity PK <\/td>\n<\/tr>\n
57<\/td>\n13 Determination of the wheel bulk temperature
13.1 Wheel bulk temperature with splash lubrication
13.1.1 General <\/td>\n<\/tr>\n
58<\/td>\n13.1.2 Method A
13.1.3 Method B
13.1.4 Method C
13.2 Wheel bulk temperature with spray lubrication
13.2.1 General
13.2.2 Method A
13.2.3 Method B <\/td>\n<\/tr>\n
59<\/td>\n13.2.4 Method C <\/td>\n<\/tr>\n
60<\/td>\nAnnex A (informative) Notes on physical parameters <\/td>\n<\/tr>\n
61<\/td>\nAnnex B (normative) Methods for the determination of the parameters <\/td>\n<\/tr>\n
66<\/td>\nAnnex C (normative) Lubricant film thickness according to the Elasto Hydrodynamic Lubrication (EHL) theory <\/td>\n<\/tr>\n
68<\/td>\nAnnex D (normative) Wear path definition <\/td>\n<\/tr>\n
71<\/td>\nAnnex E (informative) Notes on calculation wear <\/td>\n<\/tr>\n
72<\/td>\nAnnex F (informative) Notes on tooth root strength <\/td>\n<\/tr>\n
73<\/td>\nAnnex G (informative) Adaptation of formulae for the reference gear with results from testing <\/td>\n<\/tr>\n
76<\/td>\nAnnex H (informative) Life time estimation for worm gears with a high risk of pitting damage <\/td>\n<\/tr>\n
78<\/td>\nAnnex I (informative) Examples <\/td>\n<\/tr>\n
94<\/td>\nAnnex J (informative) Examples of limit load capacity in a range of working conditions <\/td>\n<\/tr>\n
97<\/td>\nBibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Gears. Calculation of load capacity of worm gears<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
BSI<\/b><\/a><\/td>\n2020<\/td>\n100<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":357041,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2641],"product_tag":[],"class_list":{"0":"post-357031","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\/357031","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\/357041"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=357031"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=357031"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=357031"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}