3. REINFORCING SIDE RAILS
Reinforcing side rails requires special care, as stress easily accumu-
lates near the borders between reinforced and unreinforced locations. It
is best to avoid reinforcing the frame in order to preserve a suitable distri
-
bution of mass for the chassis frame. However, when reinforcement is
unavoidable, the following precautions should be observed.
1) REINFORCEMENT MATERIALS
a Reinforcement material that come into contact with the outer edge of
side rails must be of the same material as the side rail.
Side rails material, 44000 psi {303 MPa, 31 kgf/mm
2
} yield (Hot-rolled
steel sheets and plates for automobile construction)
Thickness : 0.177 in (4.5 mm)
b For inner reinforcement materials, 36000 psi {248 MPa, 25 kgf/mm
2
}
yield hot-rolled steel for general construction is suitable.
Maximum thickness : 0.177 in (4.5 mm)
c When reinforcement materials are made into ]-shaped parts, it is
difficult to match them with the shape of the side rails. Therefore the
use of L-shaped parts is recommended.
2) SHAPE OF REINFORCEMENT MATERIALS AND MOUNTING
PRECAUTIONS
a Do not make the edges of reinforcement parts the same as those of
other reinforcement parts and crossmembers, spring brackets and
other locations where great stress is generated or where mass is
centralized.
b Do not cut the edges of reinforcement parts at right angles to the
surface. Cut them at 45º angles or less to avoid sudden changes in
side rail strength.
c Use plug welds or rivets on webbed portions to join reinforcement
parts to side rails.
d Fasten L-shaped reinforcement parts so the flange is on the side to
which side rail tensile stress is applied.
e Rivets and plug welds used to fasten reinforcement parts should be
around 2.76 to 5.91 in (70 to 150 mm) in pitch distance.
3) RIVETING
a As a rule, do not re-rivet to the same hole using a rivet of the same
diameter. In such cases, use a larger size rivet.
b When additional rivets are required due to addition of reinforcement
materials, a larger size rivet must be used.
c The edges of rivet holes should be at least 0.98 in (25 mm) from upper
and lower flanges. However, when there are inner reinforcement
materials, this distance should be at least 1.18 in (30 mm).
4) PLUG WELDS
a When making plug welds, be sure that there are at least 2.76 in (70
mm) from rivets, bolts and the like in order to avoid being damaged
by heat.
b Welding holes should be approximately 0.59 to 0.79 in (15 to 20 mm)
in diameter.
c Weld no closer than 0.98 in (25 mm) from the reinforcement material
to the edge of the welding hole.
C11
To Next Page
Loading...