German components supplier ZF is applying technology to ensure that working machines continue to be efficient, safe and productive, reports Bhushan Mhapralkar.
Destined to move earth, construction material and aid in the building of roads, dams, structures under challenging and arduous conditions, off-highway equipment like excavators, wheel loaders, and backhoes pack technology. Their form may not suggest as much but they are supported by component suppliers like ZF, which ensure their efficiency, and make them safe and productive. Manufacturing axles and transmissions (including transit mixer gearboxes) in India at its new site at Coimbatore, ZF caters to clients like JCB, Tata Hitachi, Ashok Leyland John Deere, LeeBoy and Sonalika (for tractors).
According to Prasanna Shanker, Deputy General Manager (Sales & Engineering), Industrial Technology Division (Off-highway Systems), ZF India, what would look like a simple gearbox that turns at a low rpm in a transit mixer, and has an output of 45,000 Nm, bears the load of the drum as well as the material in it, and keeps it turning so that the mixture does not solidify, rendering the material as well as the superstructure useless. The gearbox, according to Prasanna Shanker, also ensures that the drum does not come crashing into the vehicle cabin which could lead to serious safety implications.
The clutch modulator provided by ZF in a wheel loader, or back hoe loader is unique; it is made up of wet multi-disc clutches, and is a part of the ZF-WG transmission, ensuring seamless power transmission that is essential when shifting earth over a terrain that includes steep gradients. Termed as Powershift, the WG transmission series increases oil change interval to 2,000 operating hours. This brings down operating costs, increases uptime and helps to preserve environment. Primarily characterised by its versatility, the 4WG 94 transmission, which is a hydrodynamic powershift transmission, enables four-forward and three-reverse gear movements for extreme manoeuvrability. It is designed for engine output power in the range of 65 kW to 90 kW at 2,600 rpm, making it suitable for backhoe loaders especially.
As the only manufacturer offering close rear differential (with a dog clutch), according to Prasanna, the ZF Multisteer MS-B 300 front axle for backhoe loaders is designed to bear extreme stress peaks during a breakout with the bucket while retaining steering precision. The steering system is hydrostatic and the steering cylinder is integrated into the axle housing for protection; it also operates symmetrically. Combined with a negative scrub radius, this allows high manoeuvrability even with large front wheels. The Multitrac MT-B rear axle is a rigid axle designed to bear high loads; it has internal wet multi-disc brakes with high braking torques. Available with a hydraulically actuated dog-clutch, multi-disc lock or as a limited slip differential, the maximum output torque ranges from 65,000 to 123,000 Nm. The robustness of the axles becomes apparent with the static and dynamic axle load range between 9.5 and 13 tonne.
The ZF MT-G 3000 axle systems for wheel graders are robust and designed to handle up to 125,000 Nm output torque, 27-tonne vehicle weight and speed range of up to 50 kmph. Despite the highest stability and transferred power, the axle has compact dimensions and a low weight. Apart from the complete system, including chain lockers, the central part of the axle as well as the wheel ends can be ordered separately. The hydraulically actuated, power-shifting differential lock and a powerful parking brake, which serves also as safety brake, round off the axle system.
Pointing at modular axles, fail safe brakes (SAHR), lock-up converter that helps to achieve a hundred per cent fuel efficiency, the USP of ZF, concludes Prasanna, is the technology that reflects from the WG 90 Powershift transmission and MT-B 3060 axle on the Tata Hitachi TH 76 backhoe loader. This is technology that shows through the WG 160 Powershift transmission on Leeboy Motorgrader 785i, and Powershift WG 98 and MTL 3055 axle on the JCB 432 backhoe loader.