BS ISO 16287:2021 pdf download.Plain bearings — Thermoplastic bushes — Dimensions and tolerances.
1 Scope This document specifies the dimensions and tolerances for inserted thermoplastic bushes used as plain bearings with or without lubrication grooves in accordance with ISO 12128. These thermoplastic bushes are dimensionally exchangeable to wrapped bushes according to ISO 3547-1. This document is not applicable to reinforced plastics.
2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 554, Standard atmospheres for conditioning and/or testing — Specifications ISO 3547-2, Plain bearings — Wrapped bushes — Part 2: Test data for outside and inside diameters ISO 6691, Thermoplastics polymers for plain bearings — Classification and designation
3 Terms and definitions No terms and definitions are listed in this document. 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
B nominal width of bush
B fl flange thickness
C i inside chamfer
C o outside chamfer
D fl flange diameter
D H nominal housing bore diameter
D i nominal inside diameter of the bush
D i,ch inside diameter of the bush when inserted in a ring gauge middle H7
D o nominal outside diameter of the bush
r radius for flange bushes
5 Dimensions The dimensions and tolerances of the thermoplastic bushes are shown in Figures 1 and 2, according to whether cylindrical (type C) or flanged (type F), and given, in millimetres, in Tables 1, 2, 3 and 4. The surface finishes x and y represented in Figures 1 and 2 are given in Table 5. For the determination of the IT value (see ISO 286-1) of the coaxiality tolerance, the dimensions of D o are applicable. For the determination of the IT value (ISO 286-1) of the axial run-out tolerance, the dimensions of D fl are applicable.
6 Material Thermoplastics shall be in accordance with ISO 6691, e.g. PA, PET, PE, POM. For modified or other materials, details shall be subject to agreement between the supplier and the purchaser. NOTE Thermoplastics have a higher coefficient of linear thermal expansion than metals. PA absorbs more moisture than the other materials given and thus, in addition, will alter in volume. With the tolerance zones and fits specified in this document, these properties are taken into account under the following conditions: a) the bearing clearance is designed for an operating temperature of the bush of −10 °C to +50 °C and a relative ambient humidity of 20 % to 95 %; b) interference fit in the housing is achieved by the insertion interference (limit deviation of D o ) and is also maintained at operating temperatures of −10 °C to +50 °C;BS ISO 16287 pdf download.