Common symbols and units of springs

A - cross-sectional area of ​​spring material (mm2); equivalent bending stiffness (N/mm); coefficient

a - the length of the side of the angular section material perpendicular to the spring axis (mm); coefficient

B - bending stiffness of the plate (N/mm); coefficient

b - height-to-diameter ratio; the length of the side of the angular section material parallel to the spring axis (mm); coefficient

C - winding ratio of helical spring; disc spring diameter ratio; coefficient

D - spring middle diameter (mm)

D1 - inner diameter of spring (mm)

D2 - outer diameter of spring (mm)

d - spring material diameter (mm)

E - spring modulus (MPa)

F - load of spring (N)

F' - stiffness of spring

Fj - working limit load of spring (N)

Fo - initial tension of cylindrical tension spring (N)

Fr - radial load of spring (N)

Fr - radial stiffness of spring (N/mm)

Fs - test load of spring (N)

f - deformation of spring (mm)

fj - deformation under working limit load Fj (mm)

fr - static deformation of spring (mm)

fs——deformation of the spring under the test load Fs (mm); linear static deformation (mm)

fo——hypothetical deformation of the extension spring corresponding to the tension Fo (mm); central deformation of the diaphragm (mm)

G——shear modulus of the material (MPa)

g——gravitational acceleration, g=9800mm/s2

H——working height (length) of the spring (mm)

Ho——free height (length) of spring (mm)

Hs——height (length) of spring under test load (mm)

h——internal load cone height of disc spring (mm)

I——moment of inertia (mm4)

Ip——polar moment of inertia (mm4)

K——curvature coefficient; coefficient

Kt——temperature correction coefficient

ρ——density of material (kg/mm3)

σ——normal stress of spring at work (Mpa)

σb——tensile strength of material (Mpa)

σj——working limit stress of material (Mpa)

σs——tensile yield point of material (Mpa)

τ——shear stress of spring at work (Mpa)

k——coefficient

L——expanded length of spring material (mm)

l——expanded length of effective working circle of spring material (mm); free chord length of leaf spring (mm)

M——bending moment (N·mm)

m——mass of object acting on spring (kg)

ms——mass of spring (kg)

N——Number of variable load cycles

n——Number of working coils of the spring

nz——Number of supporting coils of the spring

n1——Total number of coils of the spring

pˊ——Stiffness of a single coil of the spring (N/mm)

R——Medium radius of the spring coil (mm)

R1——Inner radius of the spring coil (mm)

R2——Outer radius of the spring coil (mm)

r——Damping coefficient

S——Safety factor

T——Torque; torque (N·mm)

Tˊ——Torsional stiffness (N·mm / (o))

t——Spring pitch

tc——Cable pitch (mm)

U——Deformation energy (N·mm); (N·mm·rad)

V——Volume of the spring (mm3)

v——Velocity of the impact body (mm/s)

Zm——Bending section coefficient (mm3)

Zt——Torsional section coefficient (mm3)

α——Helix angle (o); coefficient

β——Cable twist angle (o); Cone half angle (o); coefficient

δ——Axial clearance of spring coil (mm)

δr——Radial clearance of combined spring coil (mm)

ζ——Coefficient

η——Coefficient

θ——Torsional angle of torsion bar per unit length (rad)

κ——Coefficient

μ——Poisson's ratio; length coefficient

ν——Natural frequency of the spring (Hz)

Vr——Excitation frequency of the variable load on the spring (Hz)

τb——Shear strength of the material (Mpa)

τj——Working limit shear stress of the spring (Mpa)

τo——Pulsating torsional fatigue limit of the material (Mpa)

τs——Torsional yield point of the material (Mpa)

τ-1——Symmetrical cyclic torsion fatigue limit of the material (Mpa)

φ——Torsional deformation angle (o); (rad)