ISO 19690-1:2017

Disc springs - Part 1: Calculation

ISO 19690-1:2017 specifies design criteria and features of disc springs, whether as single disc springs or as stacks of disc springs. It includes the definition of relevant concepts, as well as design formulae, and covers the fatigue life of such springs.

Rondelles ressorts — Partie 1: Calcul

General Information

• Status: Published
• Publication Date: 19-Mar-2017
• ICS: 21.160 - Springs
• Technical Committee: ISO/TC 227 - Springs
• Drafting Committee: ISO/TC 227 - Springs
• Current Stage: 9093 - International Standard confirmed
• Start Date: 22-Jun-2022
• Completion Date: 13-Dec-2025

Overview

ISO 19690-1:2017 - Disc springs - Part 1: Calculation specifies design criteria, definitions and calculation methods for disc springs used singly or in stacks. The standard provides the required design formulae, symbols and units, guidance on dimensions and designation, and methods to evaluate fatigue life, spring load, stress and energy capacity. It is intended for engineers and manufacturers performing mechanical design and verification of disc-spring elements.

Key topics and technical requirements

• Scope and applicability: Formulae apply to typical geometries where 16 < D/t < 40 and 1.8 < D/d < 2.5; consult manufacturers for unusual designs or materials.
• Terms, symbols and units: Conforms to ISO 26909 (vocabulary) and ISO 16249 (symbols).
• Dimensions and groups: Defines disc spring groups by thickness and the use of flat bearings (groups 1–3) and provides dimensional series (A, B, C).
• Design formulae (Clause 6): Includes test-load definition, coefficients, spring load calculations, design stresses at key positions (OM, I–IV), spring rate (non‑linear), and energy capacity integrals.
• Coefficients and corrections: Formulas for C, k and other coefficients, including special treatment when flat bearings or chamfer radius are present.
• Load characteristics: Non‑linear load/deflection behaviour for single springs as a function of h/t and modified curves for springs with flat bearings. Guidance on actual vs. design curves (noting deviations when s/h > 0.75).
• Stacking rules: Behavior and calculation for springs stacked in series, parallel, and mixed arrangements; guidance on guides (inner/outer) and necessary clearances.
• Fatigue and loading types: Coverage of static, moderate fatigue and dynamic loading conditions and how to account for fatigue life in design.

Applications and users

ISO 19690-1:2017 is used by:

• Mechanical and design engineers calculating disc-spring loads, stresses and spring rate
• Spring manufacturers and component suppliers for specification and quality control
• Systems engineers and safety assessors in industries using disc springs (valves, clutches, actuators, vibration isolation, power transmission) who need validated calculation methods and fatigue guidance
• Procurement and standards teams referencing consistent dimensional series and designation

Practical benefits include consistent disc spring design, reliable estimation of fatigue life, predictable stack behavior, and improved component interchangeability.

Related standards

• ISO 19690 series (other parts)
• ISO 16249 - Springs: Symbols
• ISO 26909 - Springs: Vocabulary

Keywords: ISO 19690-1:2017, disc springs, calculation, design formulae, spring rate, load/deflection, fatigue life, stacking, disc spring design.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19690-1
First edition
2017-03
Disc springs —
Part 1:
Calculation
Ressorts à disques —
Partie 1: Calcul
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
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ii © ISO 2017 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units . 1
5 Dimensions and designation . 3
5.1 General . 3
5.2 Disc spring groups . 3
5.3 Dimensional series . 4
6 Design formulae for springs . 4
6.1 General . 4
6.2 Test load . 4
6.3 Coefficients used in calculation . 4
6.4 Spring load . 5
6.5 Design stresses . 5
6.6 Spring rate . 6
6.7 Energy capacity of springs . 6
7 Load characteristics . 6
7.1 Load characteristics for a single disc spring . 6
7.1.1 Load/deflection curve . 6
7.1.2 Design and actual load characteristics. 7
7.2 Load characteristics for stacks of disc springs . 8
7.2.1 General. 8
7.2.2 Stacking in parallel . 8
7.2.3 Stacking in series . 9
7.2.4 Stacking in parallel and series.10
8 Design stresses .11
9 Types of loading .12
9.1 Static loading and moderate fatigue conditions .12
9.2 Dynamic loading .12
Bibliography .13
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
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ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
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World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 227, Springs.
A list of all the parts in the ISO 19690 series can be found on the ISO website.
iv © ISO 2017 – All rights reserved

INTERNATIONAL STANDARD ISO 19690-1:2017(E)
Disc springs —
Part 1:
Calculation
1 Scope
This document specifies design criteria and features of disc springs, whether as single disc springs or
as stacks of disc springs. It includes the definition of relevant concepts, as well as design formulae, and
covers the fatigue life of such springs.
2 Normative references
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 16249, Springs — Symbols
ISO 26909, Springs — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 26909 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at www .iso .org/ obp
— IEC Electropedia: available at www .electropedia .org
4 Symbols and units
For the purposes of this document, the symbols and units given in ISO 16249 and Table 1 apply.
Table 1 — Symbols and units for design calculation
Symbol Unit Parameter
C , C , C , C — coefficients
1 2 3 4
D mm external diameter of spring
D mm diameter of centre of rotation
d mm internal diameter of spring
modulus of elasticity of material
2 2
E N/mm (carbon steel and carbon alloy steel: 206 000 N/mm )
(other materials: respective modulus of elasticity of material )
F N spring load
F N design spring load when spring is in the flattened position
c
F N spring load at the time of combining springs
G
F N spring test load at H
t t
H mm height of spring when measuring spring load, H = H – 0,75 h
t t 0 0
H mm free height of spring
h mm initial cone height of springs without flat bearings, h = H – t
0 0 0
h , mm initial cone height of springs with flat bearings, h , = H – t
0 f 0 f 0 f
i — number of springs combined in series
k , k — coefficients
1 2
L mm free height at the time of combining springs
N — number of cycles for fatigue life
n — number of springs piled in parallel
OM — point at upper surface of the spring perpendicular to the centre line at point P
P — theoretical centre of rotation of disc cross section
R N/mm spring rate
r mm chamfer radius at edge
s mm deflection of spring
s mm deflection of stack
G
t mm thickness of spring
t mm reduced thickness of single disc spring with flat bearings
f
V mm length of lever arms
V mm length of lever arms with flat bearings
f
W N·mm energy capacity of springs
α — ratio of external diameter to internal diameter
ν — Poisson’s ratio of material
σ N/mm stress at position OM
OM
σ N/mm stress at position I
I
σ N/mm stress at position II
II
σ N/mm stress at position III
III
σ N/mm stress at position IV
IV
NOTE  N/mm = MPa
2 © ISO 2017 – All rights reserved

5 Dimensions and designation
5.1 General
Figure 1 illustrates a single disc spring, including the relevant positions of loading.
a) Without flat bearings: group 1 and group 2
b) With flat bearings: group 3
Key
D external diameter of spring t thickness of spring
D diameter of centre of rotation V length of lever arms
d internal di
...