Authors:
Pochi, D.; Fanigliulo, R.; Fornaciari, L.; Vassalini, G.; Fedrizzi, M.; Brannetti, G.; Cervellini, C. |
Abstract in English:
In recent years the comfort and the preservation of the health of the
operators became central issues in the evolution of agricultural machin-
ery and led to the introduction of devices aimed at improving working
conditions. Thereby, for instance, the presence of air conditioner, sound-
proof cab and driver seat suspension became normal on agricultural
tractors. The vibrations are one of the most complex issues to deal with,
being determined by the characteristics and interaction of elements
such as tyres, axles, mainframe, cab and seat suspension. In this
respect, manufacturers are trying to improve their products, even inte-
grating these elements with new devices such as the suspension on the
front axle of the tractor, aimed at reducing the level of vibrations during
the transfers at high speed. One of these underwent tests at CRA-ING.
Since its purpose is to reduce the level of vibration transmitted to the
driver, their measurements in different points of the tractor and in dif-
ferent operating conditions, were compared in order to evaluate the
effectiveness of the device, expressed as time of exposure. The suspen-
sion system of the front axle is designed to absorb the oscillations (espe-
cially pitching) determined by irregularities in the road surface, allow-
ing an increased control of the vehicle at high speed, as demonstrated
by the test results and confirmed by the driving impressions outlined by
the operator. The action of the device under these conditions results in
an increase of the exposure time, important fact because of the rele-
vance of the road transfer operations of tractors with mounted imple-
ments or trailers to tow and of the tendency to increase the speed limit
for the road tractors (in Germany were brought to 50 km h –1 for several
years). The action just described is less evident with increasing irregu-
larity of the road surface and with the decrease of the travel speed.
Nevertheless, in such conditions, the device appears to positively work
along the other directions, in particular in the Z-axis, improving the
action of the suspension of the driver seat. |