1
Automobile Design-Frame Designs
The vehicle frame is the basic platform to which all suspension and steering linkage
parts attach. A vehicle will neither steer nor handle well if the frame is too flexible. A rigid
frame structure may pass unnecessary vibrations into the passenger compartment. The
frame and suspension design will affect the ride quality, handling, and durability, as well
as the levels of both noise and vibration.
Manufacturers use several different types of construction on their vehicles. Of these,
separate body and frame construction was the most common through the 1970's. It is
still used in large vans, pickups, and trucks. In this type of construction, the engine, drive
line,
running
gear,
and
body
mount
to
the
frame
through
insulators.
Insulators
are
synthetic rubber pads that keep road and engine noise and vibration from going into the
passenger compartment.
A second type of construction is the unitized body. This, design is by far the most
popular
in
modern
vehicles.
The
unitized
design
has
a
lightweight
structure
with
the
required strength. Tn this type of construction, the frame is welded into the body as part
of the body structure. Body panels add strength to the frame pieces. The running gear
and
drive
line
are mounted
to
the
unitized
body
through
large,
soft
synthetic
rubber
insulators. The insulators minimize the transfer of noise and vibration. If the insulators
are
too
soft,
they
will
allow
too
much
running
gear
and
drive
line
movement.
This
movement, called compliance, affects vehicle handling and control. If the insulators are
too
hard,
they
will
not
insulate noise
and
vibration
as
they
should.
The manufacturer
carefully designs the insulators and puts them where they will be in a vehicle with low