Detail of GB/T 273.3-2020

Introduction of GB/T 273.3-2020

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. GB/T 273 Rolling bearings—Boundary dimensions, general plan consists of three parts: ——Part 1: Tapered roller bearings; ——Part 2: Thrust bearings; ——Part 3: Radial bearings. This is part 3 of GB/T 273. This part is developed in accordance with the rules given in GB/T 1.1-2009. ——This part replaces GB/T 273.3-2015 Rolling bearings—Boundary dimensions, general plan—Part 3: Radial bearings and the following technical changes with regards to GB／T 273.3-2015: ——The width value and smallest single chamfer dimension of radial bearings for some dimension series in diameter series 8, 9, 0 and 1 are supplemented (see Tables 2-5; Tables 2-5 of Edition 2015); ——The dimension range of radial bearings of diameter series 8, 9, 0, 1, 2, 3 and 4 has been expanded (see Tables 2-8; Tables 2-8 of Edition 2015); ——Some normative references are referred to as bibliography(see bibliography; clause 2 of Edition 2015); This part, by means of translation, is identical to ISO 15: 2017 Rolling bearings—Radial bearings—Boundary dimensions, general plan. The Chinese documents consistent and corresponding with the normative international document in this part are as follows: ——GB/T 305-2019 Rolling bearings—Snap ring grooves and snap rings for radial bearings—Dimensions，geometrical product specifications (GPS) and tolerance values (ISO 464: 2015, MOD) ——GB/T 6930-2002 Rolling bearings—Vocabulary (ISO 5593: 1997, IDT) ——GB/T 20057-2012 Rolling bearings—Cylindrical roller bearings—Chamfer dimensions for loose rib and non-rib sides (ISO 12043: 2007, IDT) ——GB/T 20058-2017 Rolling bearings—Single-row angular contact ball bearings—Chamfer dimensions for outer ring non-thrust side (ISO 12044: 2014, IDT) Editorial changes have been made in this part as follows: ——To be consistent with the existing standard series, the standard name is changed to Rolling bearings—Boundary dimensions, general plan—Part 3: Radial bearings; This part was proposed by the China Machinery Industry Federation. This part is under the jurisdiction of the National Technical Committee on Rolling Bearing of Standardization Administration of China (SAT/TC 98). The previous editions of this part are as follows: ——GB 273-1964; ——GB 273.3-1982，GB 273.3-1988，GB/T 273.3-1999，GB/T 273.3-2015. Introduction This part of GB/T 273 is to restrict the number of radial bearing sizes just enough to ensure economic production, yet provide a sufficient number of sizes to satisfy present and future needs of bearing users. These needs are comprehensive and varying. Therefore, this document needs to embrace a wide range of numerically determined sizes and proportions and can even be extended according to the guidelines given in Annex A. Tapered roller bearings, insert bearings and some types of needle roller bearings and instrument precision bearings standardized do not conform to this part because the dimensions given are not found to be optimal for the bearings in question. Rolling bearings— Boundary dimensions, general plan— Part 3: Radial bearings 1 Scope This part of GB／T 273 specifies preferred boundary dimensions for radial bearings of the diameter series 7, 8, 9, 0, 1, 2, 3 and 4. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. ISO 464 Rolling bearings—Radial bearings with locating snap ring—Dimensions，geometrical product specifications (GPS) and tolerance values ISO 5593 Rolling bearings—Vocabulary ISO 12043 Rolling bearings—Single row cylindrical roller bearings—Chamfer dimensions for loose rib and non-rib side ISO 12044 Rolling bearings—Single-row angular contact ball bearings—Chamfer dimensions for outer ring non-thrust side 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 5593 apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: ——ISO Online browsing platform: available at https: //www.iso.org/obp ——IEC Electropedia: available at http://www.electropedia.org/ 4 Symbols For the purposes of this document, the symbols given in ISO 15241[3] and the following apply. The symbols shown in Figure 1 and given in Tables 1 to 8 denote nominal dimensions, unless specified otherwise. Key: B——earing width; D——bearing outside diameter; d——bearing bore diameter; r——chamfer dimension; rsmin——smallest permissible single chamfer dimension. Figure 1 Radial bearings 5 Boundary dimension Boundary dimensions for radial bearings of the diameter series 7, 8, 9, 0, 1, 2, 3 and 4 are given in Tables 1 to 8. The chamfer dimensions given in Tables 1 to 8 do not always apply to the following: ——the groove side of bearing rings with snap ring groove (these shall be in accordance with ISO 464); ——the loose rib and the non-rib sides of cylindrical roller bearing rings (these shall be in accordance with ISO 12043); ——the non-thrust side of angular contact bearing outer rings (these shall be in accordance with ISO 12044). Chamfer dimension, r, applies at the corners indicated in Figure 1 and is specified with rsmin in Tables 1 to 8. The chamfer dimensions for inner rings of bearings with tapered bore may be smaller than those shown in Tables 1 to 8. The corresponding largest single chamfer dimensions to the rsmin dimensions in Tables 1 to 8 are given in ISO 582[2].

Contents of GB/T 273.3-2020

Foreword i Introduction iii 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols 5 Boundary dimension Annex A (Informative) Guidelines for the extension of boundary dimensions for radial bearings Bibliography