Kiruna Truck Mining

rNew Series of Underground Trucks from Kiruna Truck
Kiruna Truck has introduced a new articulated four-wheel drive underground truck line, the M40/M50 units of 40 and 50 mt net load capacity. For decades the Kiruna Truck design has offered one of the best capacity- to-net-weight ratios on the market. The new models are no exception and are designed for high transport capacity in small haulagetunnels and development/production drifts.
The new trucks are powered with the new water-cooled Deutz V 6-8 or the Detroit Series 2000 V8 engines in combination with the latest Allison automatic transmission with integrated retarder for maximum braking efficiency, especially downhill loaded. This along with a two-speed Drop box, integrated longitudinal differential, and Kiruna drive axles give thebest power-to-weight ratio and improve tire economy. Kiruna Truck says the installed power-to-net-weight ratio is significantly better than competitors -- in some cases almost 80% better. This is especially advantageous in ramp haulage giving increased speeds and lower journey times and transport costs.
The two-speed Drop box makes it possible to utilize optimum engine torque in every gear, andthe longitudinal differential eliminates driveline windup during turning. A typical articulated underground mining truck has its turning center located closer to the front axle, which results in the front and rear axles following different tracks when turning. Without longitudinal differential, a full steer and 180 degrees turn results in some 5-6 revolutions windup in the propeller shafts betweenfront and rear axles that needs to be compensated for by wheel slip.
In addition, the load distribution of a typical two-axle articulated truck causes different tire-rolling radii and driveline windup. This distribution is normally 45% front and 55% rear. When traveling on a 1:7 incline, the load distribution changes to 42% front and 58% rear. In a truck with a total weight of 80 mt and 29.5 x 29tires front and rear, the 16% difference in load distribution results in about a 22-mm difference in loaded radius. The rolling circumference for the front wheel will then be around 5,425 mm for the front axle and 5,290 mm for the rear axle. Assuming the total ratio in the drive axle is 25:1, for every 1,000 m traveled in a 1:7 incline the windup in the driveline will be 120 revolutions, whichalso needs to be compensated for. The compensation by wheel slip results in shock forces in the driveline and consequent higher wear and maintenance. This problem is eliminated by the longitudinal differential.
The new trucks have multiple wet disc brakes with forced cooling on all wheels and a spring-applied fail-safe parking and emergency brake for optimum safety. Kiruna Truck says that itsunique solution of combining hydraulic-applied service brakes with spring-applied parking/emergency brake avoids the typical "bad pedal feel" that goes with negative (spring-applied) service brakes that are the common solution.
Full 360 degrees oscillation eliminates torsion stresses between front and rear frames and ensures that all wheels have the same ground contact in all conditions. Theturning-ring oscillating hitch in front of the steering pivot equalizes the load on both front wheels despite the turning angle. This eliminates the problem of a standard hitch located behind the steering pivot, which results in load distribution from inner to outer wheels and increases with the turning angle giving the outer wheel more load and sink during turning.
The A-frame front axle suspensionsystem is said to give the driver optimum comfort and the chassis suspension with rubber elements and shock absorbers is a low-maintenance solution with high durability. To reduce loading shakes and further enhance driver comfort, the same suspension is also used for the rear axle.
The truck is equipped with a load sensing system with a variable piston pump to optimize the use of energy for the...