Leaf springs - Technical specifications
1 Scope
This standard specifies the technical requirements and test methods for leaf springs.
This standard is applicable to leaf springs used in road vehicles (hereinafter referred to as "springs") and may also serve as a reference for springs used in other vehicles.
2 Normative references
The following referenced documents are indispensable for the application 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.
GB/T 224 Determination of the depth of decarburization of steels (GB/T 224-2008, ISO 3887: 2003, MOD)
GB/T 230.1 Metallic materials - Rockwell hardness test - Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T) (GB/T 230.1-2009, ISO 6508-1: 2005, MOD)
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method (GB/T 231.1-2009, ISO 6506-1: 2005, MOD)
GB/T 1805 Spring - Vocabulary
GB/T 2828.1 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (GB/T 2828.1-2012, ISO 2859-1: 1999, IDT)
GB/T 31214.1 Springs - Shot peening - Part 1: General procedures (GB/T 31214.1-2014, ISO 26910-1: 2009, IDT)
GB/T 33164.1 Spring steels for automotive suspension system - Part 1: Hot rolled spring steel flat bars
JB/T 10802 Specification for shot peening of springs
ISO 683-14 Heat-treatable steels, alloy steels and free-cutting steels - Part 14: Hot-rolled steels for quenched and tempered springs
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 1805 apply.
4 Parameter names, symbols, and units
For the purposes of this document, the parameter names, symbols, and units given in Table 1 apply. For convenience of use, working schematic diagrams of leaf springs are given in Figure 1.
Table 1 Parameter names, symbols, and units
S.N. Parameter name Symbol Unit Description
1 Spring end width bA mm Width of the spring eye or sliding end.
2 Assembled spring width bE mm Width of the assembly in the range of U-clamping.
3 Camber C mm Perpendicular distance from the first tension side surface at the spring installation center (center bolt or the center pin) to the straight line connecting the load-supporting points of the spring.
4 Free camber C0 mm Camber of the spring when free or at zero load.
5 Design camber Cd mm Camber under design (nominal) load.
6 Eye inner diameter dA mm Inner diameter of the spring eye.
7 Eye bush inner diameter di mm Inner diameter of the spring eye bush.
8 Load F N Total spring force.
9 Design load Fd N Design (nominal) load of the spring.
10 Maximum test load Fmax, t N Maximum load of the spring given during performance tests.
11 Height H mm Overall height of the spring.
12 Free height H0 mm Height of the spring when free or at zero load.
13 Design height Hd mm Height of the spring under design load.
14 Span l mm Distance between the load-supporting points of the spring.
15 Free span l0 mm Span when free or at zero load.
16 Fixed half span lA mm Length of the span between the fixed end and the center.
17 Straight span lST mm Length of the span between the load-supporting points of the spring when the first leaf is straight.
18 Fixed half straight span lST, A mm Length of the span between the fixed end and the center when the first leaf is straight.
19 Spring rate R N/mm Load required to deflect the spring by one unit of deflection.
20 Deflection s mm Variation of camber of the spring under load.
21 Design deflection Sd mm Deflection under the design load.
22 Clamping deflection Sd, j mm Design deflection of the spring in a clamped state.
23 Maximum test deflection Smax, t mm Deflection under the maximum test load.
24 Flank bending δ mm Side bending deformation of the leaf (See Figure 11).
25 Design stress σd MPa Under design load (in a clamped state):
Average stress at the root of the multi-leaf spring;
Stress at the maximum stress point of the few-leaf spring.
26 Specific stress MPa/mm Stress per unit deflection of the spring in a clamped state, i.e., σd/sd, j
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Parameter names, symbols, and units
5 Spring types
6 Technical requirements
7 Test method
8 Acceptance rules
9 Marking, packaging and storage
Annex A (Informative) Comparison between clause/subclause numbers in this standard and those in ISO 18137: 2015
Annex B (Informative) Technical deviations between this standard and ISO 18137: 2015 and their justifications
Annex C (Informative) Test methods of leaf springs
