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Tooth chain in the automotive industry

01 March 2019

Automotive supplier Hirschvogel Eisennach relies on Renold tooth chains for a long-lasting and safe solution for the transport of hot steel blanks.

"The interlinking of steelworking machines is a huge challenge," affirms Dennis Reinhardt. The reasons for this vary: first, the 1,200 ° C hot parts are directly on the transport chain, so that it must be absolutely heat-resistant. The Renold transport chain solves this problem by their involute teeth, so that the chain does not expand despite the heat.

Furthermore, aggravating added that form on the surfaces of the steel parts by heating oxide layers and this scale then peels off. The tinder is hard and crumbles and settles like salt in the joints. Therefore, additional cleaning discs are used, with which the chain is cleaned with each deflection over the gear, so that the scale falls out and cannot stick to the chain. Dennis Reinhardt comments on these conditions: "That's what a chain has to endure. Here, the statement of functional reliability and long service life due to low wear reaches a completely new dimension. We can only confirm both here."

High-alloyed, stable & fast

The Renold tooth chain for high-temperature applications consists of a high-quality tempered steel. The sprockets are made of high-alloyed tool steel with natural core strength, which is additionally vacuum-hardened. Hirschvogel Eisenach uses the transport chains in the standard widths of 85 and 100 mm, of which the longest chain measures 10 m with a center distance of 5 m. The chains run here without lubrication, as a lubricant in the hot environment char and thus could cause even more pollution or wear. Due to the high production rate of 15 seconds, the chains move despite the sliding friction on the sliding bed at 1m / sec at high speed. "That's why they have to run at such a high speed because the heated parts would otherwise cool down on the approximately 5 m long path between the annealing furnace and the press and would then be unworkable," Reinhardt adds.

Werner Weber, owner of the engineering office Weber in Heilbad-Heiligenstadt, put out the transport chains for the Marksuhl plant. "To be on the safe side, we duplicated the middle guide of the transport chain so that each chain link now has a guide that engages in the groove of the sprocket," he explains. There were good reasons for the continuity: both the long wheelbase and the workpieces slid across the conveyor belt, which could push the chain to the side, were the decisive criteria. At the same time, this extension causes the wear of the guide plates is reduced and their life is increased.

As an automotive supplier, Hirschvogel has to continuously produce Eisenach, prevent unplanned plant shutdowns and ensure reliable means of production. Therefore, the tinder accumulation and the forging necessary, hardening release agent particularly stressed chain was divided. The part leading directly to the machine can now be simply pulled out on a stand and cleaned every week.
Dennis Reinhardt sums up the positive changes that have occurred in terms of maintenance through the use of Renold transport chains: "Previously, we had to replace the conveyor belt every three months because the teeth were rubbing off on the pinions. Each time nearly six hours of production time have been lost through removal, cleaning and assembly. In contrast, we now plan the chain change in the context of the scheduled annual maintenance of the system, keep the required 7 maintenance shutdowns saved material and thus save seven maintenance downtime only in terms of the means of transport. "
In addition to the transport chains for the glowing hot workpieces, Hirschvogel Eisenach also uses another Renold toothed chain with a width of 270 mm for transporting pallets. Due to their high shear and flexural strength, the chain can easily withstand the heavy pressure of the heavyweight goods.