Page 263 - Automotive Engineering Powertrain Chassis System and Vehicle Body
P. 263

Steering      CHAPTER 9.1

                                                              ball bearings 2 and 3, the lock-nut must be loosened and
                                                              the sealing housing cover re-tightened.
                                                                Only a few standard design larger saloons can be found
                                                              on the road with manual recirculating ball steering. For
                                                              reasons of comfort, newer passenger cars of this type have
                                                              hydraulic power-assisted steering. The same applies to
                                                              commercial vehicles; only a few light vans are still fitted
                                                              with manual configurations as standard and even these are
                                                              available with power-assisted steering as an option.
           Fig. 9.1-14 Lemfo ¨ rder Fahrwerktechnik pre-lubricated tie rod
           joint, used on passenger cars and light vans. The joint housing 1
           has a fine thread on the shaft (M14   1.5 to M22   1.5) and is  9.1.4 Power steering systems
           made of annealed steel C35V; surface-hardenable steel 41Cr4V is
           used for the ball pivot 2.
           The actual bearing element – the one-part snap-on shell 3 made  Power steering systems have become more and more
           from polyacetal (e.g. DELRIN, made by Dupont) – surrounds the  widely used in the last few years, due to the increasing
           ball; the rolled-in panel cover 4 ensures a dirt- and waterproof
           seal. The polyurethane or rubber sealing gaiter 5 is held against  front axle loads of vehicles on the one hand and the
           the housing by the tension ring 6. The gaiter has a bead at  trend towards vehicles with more agile steering prop-
           the bottom (which the second tension ring 7 presses against the  erties and hence direct transmission steering systems on
           spigot) and a sealing lip, which comes into contact with the  the other. With the exception of some members of the
           steering arm.                                      ‘sub-compact’ class, power steering systems are op-
           The ball pivot 2 has the normal 1:10 taper and a split pin hole
           (position 8). If there is a slit or a hexagonal socket (with which  tionally or automatically included as one of the standard
           the spigot can be held to stop it twisting), a self-locking nut can  features.
           be used instead of a slotted castle nut and split pin.  Manual steering systems are used as a basis for power
                                                              steering systems, with the advantage that the mechani-
           slightly angular arrangement of the gearing can be seen  cal connection between the steering wheel and the
           top right. This is necessary for alignment bolt 1 to over-  wheel and all the components continues to be main-
           come the play of the wheels when pointing straight  tained with or without the help of the auxiliary power.
           ahead, by axial adjustment. If play occurs in the angular  The steering-wheel torque applied by the driver is





































           Fig. 9.1-15 Mercedes Benz recirculating ball steering suitable for passenger cars and light vans; today, apart from in a few exceptional
           cases, this is only fitted as a hydraulic power-assisted version. Pitman arm 9 is mounted onto the tapered toothed profile with a
           slotted castle nut 11 (Fig. 9.1-24).


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