ISO/DIS 8139:2026(en)

ISO/TC 131/SC 3

Date: 2025-12-20

Secretariat: DIN

Pneumatic fluid power — Cylinders, 1 000 kPa (10 bar) series — Mounting dimensions of rod-end spherical eyes

Transmissions pneumatiques — Vérins, série à 1 000 kPa (10 bar) — Dimensions d'interchangeabilité des tenons à rotule d'extrémité de tige

© ISO 2026

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Contents Page

Foreword iv

Introduction v

1 Scope 1

2 Normative references 1

3 Terms and definitions 1

4 Mounting dimensions 1

5 Application instructions 3

5.1 Installation 3

5.2 Bearing life 3

5.3 Lubrication 3

6 Example of ordering designation 3

7 Identification statement (reference to this document) 3

Bibliography 4

Foreword

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This document was prepared by Technical Committee ISO/TC 131, Fluid power systems, Subcommittee SC 3, Cylinders.

This fourth edition cancels and replaces the third edition (ISO 8139:2009), which has been technically revised.

The main changes are as follows:

— updating the normative references;

— updating Figure 1 to display the position of the dimension EN taking into account the previous position of the dimension EN as mentioned in ISO 12240 series.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

In pneumatic fluid power systems, power is transmitted and controlled through a gas under pressure within a circuit.

One component of such systems is the pneumatic fluid power cylinder. This is a device that converts power into linear mechanical force and motion. It consists of a movable element, i.e. a piston and piston rod, operating within a cylindrical bore.

Pneumatic fluid power — Cylinders, 1 000 kPa (10 bar) series — Mounting dimensions of rod-end spherical eyes

This document specifies the mounting dimensions required for interchangeability of rod-end spherical eyes of pneumatic cylinders. The rod-end spherical eyes have been designed specifically for use with 1 000 kPa [10 bar^[1]] series cylinders manufactured in accordance with ISO 6432 and ISO 15552, but this does not limit their application.

The spherical bearing end eyes are used on piston rods of pneumatic cylinders for mechanically transmitting the cylinder force under oscillatory rotational and tilting movements. The design of the rod-end spherical eyes is based on the maximum forces resulting from the specified internal diameter of the cylinders and pressure according to ISO 6432, ISO 15552 and ISO 21287.

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 5598, Fluid power systems and components — Vocabulary

ISO 6099, Fluid power systems and components — Cylinders — Identification code for mounting dimensions and mounting types

For the purposes of this document, the terms and definitions given in ISO 5598 apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https://www.iso.org/obp

— IEC Electropedia: available at https://www.electropedia.org/

The identification code for mounting dimensions and mounting types is in accordance with ISO 6099.

See Figure 1 and Table 1 for mounting dimensions.

Figure 1 — AP6 — Rod-end spherical eyes

Table 1 — Dimensions of AP6 — Rod-end spherical eyes

Dimensions in millimetres

5.1.1 Usually a tolerance of m6 (see ISO 286‑2) is used for the shaft fitting the spherical plain bearing bore.

However, in exceptional cases (for example cylinder installation difficulties), a tolerance of f7 can be admitted. In this instance, a case-hardened shaft is recommended as movement occurs between the shaft and the bearing bore. Lubrication shall then be effected through the shaft.

5.1.2 The specified tilting angle of ±4° can still be obtained when the clevis inner faces abut the side faces of the inner ring of the spherical plain bearing.

5.1.3 The rod-end spherical eyes shall be locked with a locking nut.

5.2.1 The life of the spherical plain bearing is influenced by many factors such as specified load, direction of load, angle of oscillation, type of lubricant and frequency of lubrication.

5.2.2 The spherical plain bearings are designed to give an acceptable bearing life under normal operating conditions.

5.2.3 When a constant unidirectional load is applied or other unusual operating conditions exist, consultation with the supplier is recommended.

5.3.1 Sufficient lubrication shall be provided for the satisfactory performance of the rod-end spherical eyes.

5.3.2 The method and frequency of such lubrication depend on the particular operating conditions.

A rod-end spherical eye with a bore of CN = 20 mm and steel-on-steel surface shall be designated as follows:

AP6 ISO 8139:—, 20

It is strongly recommended to manufacturers who have chosen to conform to this document that the following statement be used in test reports, catalogues and sales literature:

“Pneumatic cylinder rod-end spherical eye mounting dimensions in accordance with ISO 8139:—, Pneumatic fluid power — Cylinders, 1 000 kPa (10 bar) series — Mounting dimensions of rod-end spherical eyes.”

Bibliography

[1] ISO 286‑2, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes — Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts

[2] ISO 6432, Pneumatic fluid power — Single rod cylinders, 1 000 kPa (10 bar) series, bores from 8 mm to 25 mm — Basic and mounting dimensions

[3] ISO 15552, Pneumatic fluid power — Cylinders with detachable mountings, 1 000 kPa (10 bar) series, bores from 32 mm to 320 mm — Basic, mounting and accessories dimensions

[4] ISO 21287, Pneumatic fluid power — Cylinders — Compact cylinders, 1 000 kPa (10 bar) series, bores from 20 mm to 100 mm

1. 1 bar = 0,1 MPa = 10⁵ Pa; 1 MPa = 1 N/mm². ↑