DIN Standards Committee Petroleum and Natural Gas Industries
DIN ISO 21940-32
Mechanical vibration - Rotor balancing - Part 32: Shaft and fitment key convention (ISO 21940-32:2012)
Mechanische Schwingungen - Auswuchten von Rotoren - Teil 32: Behandlung von Passfederverbindungen (ISO 21940-32:2012)
Overview
DIN ISO 21940-32 It is often impossible or economically unreasonable to balance rotors with fitments after they have been assembled; the rotor components which also may originate from different suppliers are therefore balanced separately. For coupling the fitment(s) to the shaft, keys are often used. There are three methods (or key conventions) for balancing shafts and fitments coupled together with keys: - full-key convention; - half-key convention; - no-key convention. This standard unifies the key conventions used throughout the world and gives instructions on a marking of components balanced in accordance with the key convention applied. This standard specifies the use of half-keys. It applies to rotors balanced in a balancing machine, in their own bearings or in situ. The key convention can also be applied when measuring the residual unbalance and/or vibration of rotors with keyways, but to which fitments have not yet been assembled. This standard also applies to keys mounted on tapered shaft surfaces, to woodruff, gibhead, dowel and other special keys. The underlying International Standard ISO 21940-32 "Mechanical vibration - Rotor balancing - Part 32: Shaft and fitment key convention" has been prepared by Technical Committee ISO/TC 108/SC 2 "Measurement and evaluation of mechanical vibration and shock as applied to machines, vehicles and structures", the secretariat of which is held by DIN. Regarding the German collaboration the responsible committee is NA 001-03-06-01 (NALS/VDI C 6.1) "Auswuchten und Auswuchtmaschinen" ("Balancing and balancing machines") at the Acoustics, Noise Control and Vibration Engineering Standards Committee at DIN and VDI. This standard differs from DIN ISO 8821:1991-10 as follows: a) the number of the standard has been changed; b) statements relating to the elapsed implementation date, expired transition period and key convention usage in the past have been deleted; c) the standard has been editorially revised and adopted to the current terminology.
