Overview
ISO 11687-1:2020 - Plain bearings - Pedestal plain bearings - Part 1: Pillow blocks specifies the design characteristics and dimensional requirements for pillow blocks (pedestal plain bearings) in size ranges 9 to 28 and 35 to 71. The standard covers bearing housings, shaft design, materials, tolerances, surface finish and lubrication/cooling options, and is intended primarily for use in the electrical and turbo engineering industries.
Key topics and technical requirements
- Types and designation
- Classification by housing (G = without cooling fins, R = with cooling fins), heat dissipation (N, W, U, T, Z), bore shape and lubrication (C, L, Y, V), and thrust bearing type (Q, B, K, A).
- Example designation format: Pillow block ISO 11687-1 - 14 - 125 - RZLK.
- Dimensions and interchangeability
- Dimensional tables and figures define required dimensions for the two size ranges; conformance is required to specified dimensions rather than to illustrated shapes.
- Shaft and bearing geometry
- Includes shaft dimensions (see tables) and recommendations for bore shapes (cylindrical, lobed) and split oil ring options.
- Materials
- Housing: grade 300 grey cast iron (ISO 185) or by agreement.
- Half‑bearing/backing and bearing materials: examples include S235 B, C10R/C15R, GE 200/GS 200 and tin-casting alloy bearing metal (ISO 4381).
- Oil ring and seals: copper-zinc alloy (ASTM B124/B124M) and various copper/aluminum/plastic options by agreement.
- Surface finish and tolerances
- Machined surfaces: ISO 2768-1/-2 tolerances (mH); unmachined castings: ISO 8062-3 grading.
- Surface roughness per ISO 1302: mounted surfaces Ra = 3.2 µm, sliding surfaces Ra = 0.8 µm.
- Design and features
- Housing protection against corrosion, oil‑resistant paint for internal surfaces, lifting/handling provisions, interconnected oil spaces for pressure compensation, and provisions for inspection plates and drain/connection points.
- Special conditions
- Options for cooling (natural, water, circulation, external oil cooling) and design variants to suit space or application constraints; seals and some connections are by agreement.
Applications and users
- Targeted industries: electrical engineering, turbo machinery, power generation and any application using pedestal plain bearings.
- Primary users:
- Bearing and machine designers, OEMs and component manufacturers
- Maintenance and reliability engineers specifying replacements
- Procurement and standards/quality managers preparing technical specifications
- Practical uses: specifying interchangeable pillow block housings and shafts, ensuring correct lubrication/cooling arrangements, and achieving consistent tolerances and finishes for long service life.
Related standards
Normative references in ISO 11687-1:2020 include:
Keywords: ISO 11687-1:2020, pillow blocks, pedestal plain bearings, bearing housing, shaft design, surface roughness, tolerances, lubrication, cooling, bearing materials.