Berco targets overtime for undercarriages
22 September 2021
Berco, part of the thyssenkrupp Forged Technologies Business Unit, recently announced several additions to its product portfolio including new generations of its BPR2 (Berco Positive Pin Retention2 System) and Robustus (ROtating BUShing Undercarriage System).
The company, which manufactures undercarriage components to heavy equipment manufacturers and to the aftermarket, produces products that incorporate customized solutions for applications that operate in unique and often extreme conditions.
Robustus is a specially engineered system used in D5 and D6 class dozers. According to Berco the rotating bushing system, in conjunction with BPR2, increases the life of the lubricated track group assemblies in applications operating in highly abrasive terrain.
This will be of particular interest for operators of heavy machinery as the undercarriage accounts for 50 percent or more of the total lifetime cost of a machine, including maintenance and downtime.
Berco has this year been supplying BPR2 and Robustus components to a global equipment manufacturer for selected 150 to 250 hp range dozers (112 to 186 kW), both with the standard and rotating bushing versions designed for especially demanding work.
Francesco Grenzi, Berco’s executive director of R&D, explained that in a machine fitted with a conventional undercarriage, bushings are constantly subjected to wear because sprocket bushings slide onto the sprocket tooth roots during engagement.
With Robustus, the bushings are designed to rotate when engaged by a sprocket, reducing the wear rate of the bushings as the wear is more balanced. The company claimed that this can deliver as much as a 35% increase in track life and provide a maximum of 6,000 hours of operation without maintenance, resulting in an overall reduction of operating costs of up to 30%.
Robustus, now in its third generation, is fully compatible with existing frames and standard components of D6 and D5 class machines.
The BPR2 system strengthens the performance of Robustus as it assures more reinforcement on the sealing points, despite Robustus having four sealing points instead of two. The BPR2 system uses a metal ring plastically deformed as a mechanical locking element. The ring is pressed in between the pin and link, locking the joint to specific, pre-determined end-play levels.
Berco said that the BPR2 prevents end-play generation and increases the sealing of the joint by at least 25%, translating into an extended track life, and even machines equipped with wide shoe arrangements can mount BPR2 in order to ensure the reduction of torsional effects on the joint.
The use of the BPR2 system on conventional track group assemblies is usually recommended for heavy duty applications such as demolition, mining, large construction and any applications that generate large loads and impacts, twisting the chain and generating axial movements.
Berco targets mining excavators
Berco recently worked on extending the service intervals of its undercarriage for mining excavators.
The target of the company’s efforts was as much as 20,000 hours between maintenance, a goal that Grenzi described as difficult because of the high work efficiency of the most advanced mining excavators and the different working modes in open pit mines.
The travel rate of an undercarriage in mining is also something that can significantly vary between applications. For example, during blasting operations machines need to be evacuated from the area before detonation.
Berco said that in situations where higher travel levels are required then carburized bushings are typically recommended, because they are the most suitable bushing type for effectively reducing the speed of wear.
For applications that do not encounter frequent travel, undercarriage parts are still often subjected to significant wear. For example, continuous hammering of front shovels may not lead to accelerated bushing wear, but can cause other side effects such as cracking.
IHT bushing solution aimed at heavy application
Berco’s solution has been to use both quenched and tempered, and induction hardened and tempered (IHT) bushings. The bushing’s material is also quenched and tempered steel with boron to increase hardness. Berco claimed that the specially produced bushings deliver even more added value when fitted on reinforced chain.
The IHT bushing solution is designed for heavy application such as track chains used on 200 ton to 400 ton machines. The IHT bushing solutions were fitted in November 2020 to a pair of machines operating in Russia’s most extreme environments.
Berco declared that it provides high resistance to wear, outstanding resistance to impact and can deliver up to 20,000 hours of operation in the field without maintenance.
The company has also developed rotary forged (rotoforged) steel rollers for mining applications.
Berco maintained that it expects its rotoforged rollers to offer significant benefits to machines that encounter huge load transfers during working operations, such as mining excavators that weigh above 200 tons.
Berco insisted that for applications of this size and even heavier, 350 tons to 400 tons, then the rollers are under especially high pressure as they carry all of the inertia of the vehicle.
Steel that has undergone the rotoforging process acquires a high microstructure and compactness, resulting in toughness values double those of conventional steel.
According to Berco the rollers need to be made of perfectly formed steel, which is why the rotoforging process is an ideal solution as rotoforged rolled steel has its microstructure transformed down to the core that results in a much stronger and more robust structure.
This story first appeared in the September issue of Diesel Progress. For a free print or digital subscription, click here.