ISO 14218 pdf download.Aerospace — Airframe ball bearings, single-row, self-aligning, sealed, heavy duty — Inch series
1 Scope
This International Standard specifies the characteristics, boundary dimensions, tolerances, internal clearances and permissible loads of inch series, single-row, self-aligning, sealed, heavy duty ball bearings used in airframe applications. These bearings are full complement (without cage) with a single row of balls. These bearings are designed to withstand only slow rotations and oscillations under radial load and are intended for use between fixed and moving parts of an aircraft structure and their control surfaces. The airframe ball bearings covered by this International Standard are designed to operate in the temperature range of – 54 °C to + 1 50 °C.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 683-1 7:— 1 ) , Heat-treated steels, alloy steels and free-cutting steels — Part 1 7: Ball and roller bearing steels . ISO 1 1 32:1 980, Rolling bearings — Tolerances — Definitions . ISO 2082:1 986, Metallic coatings — Electroplated coatings of cadmium on iron or steel . ISO 4520:1 981 , Chromate conversion coatings on electroplated zinc and cadmium coatings . ISO 5593:1 997, Rolling bearings — Vocabulary . ISO 8075:1 985, Aerospace — Surface treatment of hardenable stainless steel parts . ISO 1 41 90:1 998, Aerospace — Airframe rolling bearings: ball and spherical roller bearings — Technical specification . AMS 241 7E:1 993, Plating, zinc-nickel alloy
3 Definitions
For the purposes of this International Standard, the definitions given in ISO 5593 apply.
4 Symbols
4.1 For the purposes of this International Standard, the symbols given in ISO 1 1 32 apply. The symbols (except those for tolerances) shown in figure 1 and the values given in tables 1 and A.1 denote nominal dimensions unless specified otherwise.
5 Required characteristics
5.1 Dimensions — Tolerances — Internal clearances — Loads Values are given in table 1 . Where plating is specified, tolerances are applicable after plating. Configuration is given in figure 1 . The configuration for and installation process of seals are at the manufacturer’s option. 5.2 Surface roughness Inner and outer ring raceways and rolling elements shall have a surface roughness of R a = 0,2 µm max. Bore, side faces and cylindrical outer surface shall have a surface roughness of R a = 0,8 µm max. before surface treatment.
7 Surface treatment
7.1 All elements manufactured from corrosion-resistant steel which are not cadmium plated or zinc-nickel plated (code letter C) shall be passivated in accordance with ISO 8075 or cleaned by a mechanical method. 7.2 If made of corrosion-resistant steel, cadmium plating (code letter H) shall be subject to agreement between the customer and the manufacturer. 7.3 Where cadmium plating is specified (code letters D, M and H), it shall be in accordance with ISO 2082. The external surfaces of bearing rings, except the bore of the inner ring, shall be cadmium plated. Plating on the internal surfaces shall be at the manufacturers option, except the raceways shall not be plated. The thickness of the plating shall not be less than 7 µm and not more than 1 5 µm, except plating on the chamfers of the bore may vary from the specified thickness. The bearing shall be embrittlement-relieved within 4 h of plating by heat treatment at 1 40 °C ± 1 0 °C for a minimum of 8 h followed by chromate treatment in accordance with ISO 4520 (code letters D and H only). 7.4 Where zinc-nickel plating is specified (code letter Z), it shall be in accordance with AMS 241 7E, type 2. The surface coverage of the plating shall be as specified in 7.3. The thickness of the plating shall not be less than 7 µm or more than 1 5 µm.