Page 234 - Automotive Engineering Powertrain Chassis System and Vehicle Body

CH AP TER 8 .1 Types of suspension and drive

Fig. 8.1-56 Lancia front axle. The McPherson strut consists of the wheel hub carrier 1 and the damping part 2; the two are
connected by three screws. The lower spring seat 3 sits firmly on the outer tube and also acts as a buffer for the supplementary
spring 4. This surrounds the outer tube 2 giving a longer bearing span (path l–o, Fig. 8.1-11). The supporting bearing 5 is arranged
diagonally and thus matches the position of the coil spring which is offset to reduce damping friction. The rubber bearing 6 absorbs
the spring forces, and the rubber bearing 7 absorbs the forces generated by the damping. Disc 8 acts as a compression buffer and
plate 9 acts as a rebound buffer for this elastic bearing. Both parts come into play if the damping forces exceed certain values.
The centre of the CV joint 10 lies in the steering axis and the wheel hub 11 fits onto a two-row angular (contact) ball bearing. Guiding
joint 12 sits in a cone of the wheel hub carrier 1 and is bolted to the lower transverse control arm 13. Inelastic ball joints provide the
connection to the anti-roll bar 14. The steering axis inclination s between the centre point of the upper strut mount and guiding joint
12 and the (here slightly positive) kingpin offset at ground (scrub radius) r s are included.

poor braking force distribution (about 75% to the compensated with a drive slip control (ASR) or by
front and 25% to the rear); shifting the weight to the front axle. On the XM
complex gear shift mechanism which can also be models, Citroe ¨n moved the rear axle a long way to the
influenced by power plant movements. rear resulting in an axle load distribution of about 65%
to the front and 35% to the back. The greater the load
The disadvantage of the decreased climbing perfor- on the front wheels, the more the car tends to
mance on wet roads and those with packed snow can be understeer, causing adverse steering angles and heavy

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