Page 7 - BPW axles with air suspension Series O SL AL

Tri-axle unit with self-steering axle 3.1

G Geenneerraall
BPW axles with air suspension can be used as single axles or as multi-axle units. The axles are
connected to the vehicle chassis via trailing arms, hanger brackets and air bags.

T Trraaiilliinngg aarrmm
The rolled parabolic trailing arms control the tracking movements and braking forces. The U-shape
configuration of axle beam and trailing arms operates as a stabilizer to counteract tilting of the
superstructure during angular acceleration.

V Veerrttiiccaall ffoorrcceess
The vertical forces are introduced through the hanger brackets and air bags into the vehicle chassis.

T Trraannssvveerrssee ffoorrcceess
The transverse forces are only introduced into the chassis through the hanger brackets. They therefore
have to be reinforced to ensure that the admissible torsion loads of the chassis longitudinal member are
not exceeded. To minimise the torsion stresses, the hanger brackets of the most common BPW air sus-
pension systems are short, thus giving the transverse forces a small lever arm.

L Laatteerraall SSttaabbiilliittyy
Well matched vibration dampers and trailing arms have a positive effect on lateral stability and travel
comfort. The air suspension counteracts severe vibrations from the frame and roadway. This ensures a
uniform wheel force on the road at all times.

E Eqquuaalliissaattiioonn ooff ssttaattiicc aanndd ddyynnaammiicc aaxxllee llooaaddss
The air bags are connected to each other via air lines to ensure equalisation of static and dynamic axle
loads under all operational conditions:
- uniform axle loads on uneven road surfaces and with the superstructure at a large inclination,
e.g. through different fifth-wheel heights of the tractor units
- uniform braking action on all axles
- quiet running, also during braking
- uniform road adhesion and reduced locking tendency, less wear on tyres
- uniform brake cylinder sizes and lever length on all axles.

Remarks:
To guarantee good axle load equalisation, the air lines connecting the air bags must not have an internal
diameter of less than Ø 8 (e.g. Ø 12 x 1.5 or Ø 10 x 1).

R Raaiissiinngg aanndd lloowweerriinngg -- mmoorree fflleexxiibbiilliittyy
The vehicle can be raised and lowered with a switching valve / rotary slide valve to quickly attach and
detach semi-trailers or to adapt to different ramp heights.

A Addddiittiioonnaall aacceessssoorriieess
Further accessories and system solutions are contained in the BPW technical documentation.

D Diimmeennssiioonnss
These installation instructions only contain general dimensions and design drawings. Your contact at
BPW will be only too pleased to give you any further advice you may need.

BPW-EA-Luft 1023701e 7