17-4.Leaf spring
17-4. Leaf spring
Symbol description and unit
(1) Rectangular spring
Maximum stress:
Ð
max
=6*W*L/(b*t
2
)@@kkgf/mm
2
l
Ð
max
=
Deflection:
Â=4*W*L
3
/(E*b*t
3
)@kmml
Â=
WF Load applied to the spring@kkgfl
LF span@kmml
bF Leaf spring width@kmml
tF Leaf spring thickness@kmml
EF Young's modulus@kkgf/mm
2
l
(2) Trapezoidal spring
Maximum stress:
Ð
max
=6*W*L/(b
0
*t)@@kkgf/mm
2
l
Ð
max
=
Correction factor for shape:
k=12/(1-b
1
/b
0
)
3
*(1/2-2*b
1
/b
0
+(b
1
/b
0
)
2
*(3/2-log
e
b
1
/b
0
))
k=
Deflection:
Â=k*W*L
3
/(E*b
0
*t
3
)@kmml
Â=
WF Load applied to the spring@kkgfl
LFspan@kmml
b
0
F Leaf spring width 1@kmml
b
1
FLeaf spring width 2 @kmml
tF Leaf spring thickness@kmml
EF Young's modulus@kkgf/mm
2
l
(3) Laminated leaf spring
Bending stress:
Ð
max
=3*W*L/(2*n*b*t
2
) kkgf/mm
2
l
Ð
max
=
Deflection:
Â=3*W*L
3
/(n*b*t
3
*E)@kmml
Â=
WFLoad applied to the spring@kkgfl
nFNumber of boards@
LF span@kmml
bF Leaf spring width@kmml
tF Leaf spring thickness@kmml
EF Young's modulus@kkgf/mm
2
l
(1) Rectangular spring
(2) Trapezoidal spring
(3) Laminated leaf spring
References: "Machine Official Collection" (co-authored by Masaaki Oishi / Tatsuo Inami) Mechanical design springs, page 100, refer to rectangular springs, trapezoidal springs, and laminated leaf springs.