ISO 3019-1:2001

Overview

ISO 3019-1:2001 - Hydraulic fluid power - Dimensions and identification code for mounting flanges and shaft ends of displacement pumps and motors - Part 1: Inch series shown in metric units specifies sizes, dimensional tolerances and an identification code for two- and four-bolt mounting flanges and shaft ends used on positive-displacement rotary hydraulic pumps and motors. The part covers cylindrical keyed shafts (with and without external thread), conical keyed shafts with external thread and 30° involute spline shaft ends (in accordance with SAE J744). It presents the inch-series geometry converted to metric units for clear international use.

Key topics and requirements

• Dimensional specifications for two-bolt and four-bolt mounting flanges and multiple shaft-end types, with illustrative figures and tables for nominal sizes (e.g., 50-2, 101-4 flange codes).
• Identification code system:
  • For flanges: the number before the hyphen approximates the flange pilot diameter in millimetres; the number after the hyphen is the number of bolt holes.
  • For shaft ends: the number before the hyphen approximates the shaft major diameter in millimetres; suffix codes indicate shaft type (‑1 cylindrical keyed without thread, ‑2 cylindrical keyed with external thread, ‑3 conical keyed with external thread, ‑4 30° involute spline).
• Tolerances and geometric control: dimensions without explicit tolerances are nominal; form and position tolerances align with ISO 1101. Required flange/shaft concentricity and perpendicularity are specified (see figures), and note that rigid couplings may require closer tolerances.
• Mating component compatibility: guidance to ensure mating parts respect the specified dimensions/tolerances to avoid undue body strain or excessive transverse shaft loads.
• Preferred flange/shaft combinations and guidance for alternative combinations by agreement between purchaser and supplier.
• Normative references include ISO 68-2 (inch screw threads), ISO 1101 (geometrical tolerancing), ISO 5598 (fluid power vocabulary) and SAE J744 for spline form. Annex A gives inch thread basic dimensions.

Applications and users

ISO 3019-1 is essential for:

• Hydraulic pump and motor manufacturers and design engineers for standardizing mounting interfaces.
• OEMs and machine builders specifying interchangeable pump/motor mounts and shaft connections.
• Maintenance, procurement and quality teams ensuring parts compatibility and correct replacement components.
• Coupling and transmission designers checking shaft/flange fit, concentricity and run-out requirements.

Using ISO 3019-1 reduces design rework, improves cross-brand interchangeability and simplifies procurement of hydraulic displacement pumps and motors.

Related standards

• ISO 3019-2 (Metric series)
• ISO 68-2 (Inch screw threads)
• ISO 1101 (Geometrical tolerancing)
• SAE J744 (Involute spline dimensions)