4391 (ISO International Standard Hydraulic fluid power - Pumps, motors and integral transmissions --- Parameter definitions and letter symbols Transmissions hydrauliques -- Pompes, moteurs et variateurs - Definitions des grandeurs et lettres utilisees comme symboles Second edition - 1983-06-15 UDC 621.8.032 : 621.65/.67 Ref. No. ISO 4391-1983 (E) SO 4391-1983 Descriptors : fluid power, hydraulic fluid power, hydraulic equipment, pumps, hydraulic motors, hydraulic variable speed drive units, definitions. symbols, letters (symbols). Price based on 10 pages Copyright International Organization for Standardization Not for Resale Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (IsO member bodies). The work of developing inter- national Standards is carried out through ISo technical committees. Every member body interested in a subject for which a technical committee has been set up has the and non-governmental, in liaison with IsO, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the isO Council. international Standard ISO 4391 was developed by Technical Committee ISO/TC 131, Fluidpowersystems. This second edition was submitted directly to the iSo Council, in accordance with clause 6.11.2 of part 1 of the Directives for the technical work of ISO. It cancels and replaces the first edition (i.e. ISO 4391-1982), which had been approved by the member bodies of the following countries : Finland Netherlands Australia France Norway Austria Belgium Germany, F.R. Poland Bulgaria India Romania Canada Italy Spain Chile Sweden Japan Libyan Arab Jamahiriya Czechoslovakia USSR The member bodies of the following countries had expressed disapproval of the docu- ment on technical grounds : United Kingdom USA @ international Organization for Standardization, 1983 Printed in Switzerland i ited withoutlicense from IHS Not for Resale Contents Page 0Introduction Scope 2 Field of application 3References . Definitions . 4 Guidelines for the use of letter symbols and suffixes 5 6 Identification statement . 2 Letter symbois for characteristics . 2 Suffixes for symbols for characteristics . . . 8 3 Examples for the use of symbols with suffix for general characteristics . 9 5 Exampies for the use of symbols with suffix for pumps and motors . . . . 10 5 Examples for the use of symbols with suffix for integral transmissions . 11 8 12Definition of terms without symbols . . 9 ili tted without license from IHS Not for Resale