Cylindrical Roller Bearings for Multi-roll Mill Backup Rolls
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Koyo Cylindrical Roller Bearings for Multi-roll Mill Backup Rolls

JTEKT started producing cylindrical roller bearings for backup rolls for Sendzimir mills in the 1950s and has continued to provide superior products for customers around the world. As regards to the backup rolls assembling products, which is the Key component of the Sendzimir mill, we concluded a production agreement for licensing with SENDZIMIR JAPAN, LTD. in 1970 and now supply over 100 products for Sendzimir mills around the world. We support our customer’s operations stability not only with cylindrical roller bearings for backup rolls, but with cylindrical roller thrust bearings for...

Multi-roll mills enable our customers to utilize extremely small diameter work rolls with a choice of 12 or 20 rolls. Thereby, we are now capable of rolling hard materials such as stainless steel sheets and electrical steel sheets as well as rolling ultrathin copper. Cylindrical roller bearings for backup rolls play a significant role in obtaining this high level of efficiency. Photo by: SENDZIMIR JAPAN, LTD. 02

Cylindrical roller bearings for multi-roll mill backup rolls JTEKT has provided Cylindrical roller bearings for backup rolls with high durability and precision, contributing to the utmost performance in multi-roll mills. Required performance and issues Seal structure that maintains a favorable lubricated state Improving outer ring durability Longer inner ring rolling fatigue service life Improving outer ring rotational accuracy Improving ease of outer ring regrinding work (P15-16) Bearing configuration and features The bearings which are used for multi-roll mill backup rolls are attached to...

Long life, highly corrosion-resistant JHS is driving innovations in steel production equipment. Iron manufacturing and rolling mill lines must operate continuously while maintaining high reliability in severe production environments. Answering these needs through the realization of epoch-making long-life and high corrosion resistance is JTEKT Hyper Strong (JHS). By adopting newly developed materials and processes for bearing steel, seal materials and other components, we have realized a 2-to-4-fold increase in bearing service life compared to previously used bearings. Continuing on from...

Bearing instruction Here is an illustration of how we disassemble, assemble and inspect the bearings. Please follow this for bearing maintenance. Snap ring (2 pieces) Bearing for oil mist lubrication Cage (2 pieces) Roller (2 rows) Inner ring (2 pieces) Outer ring (1 piece) Inner ring disassembling points ※ Please use 10-40kPa for oil mist manifold pressure. Inner ring inspection points Confirm for no axial scratches on raceway Confirm no discoloration due to temperature raise Confirm no abrasion on rib face (1) Remove inner rings (both rings) Shield will be removed with inner rings due to the...

Oil seal disassembling points Oil seal inspection points (2) Remove snap ring (both pieces) (3) Remove oil seals (both pieces) 【 】 ！ Caution Be careful to not scratch the oil seal when removing the snap ring and oil seal. Confirm no cracking or chipping on seal lip part 【 】 ！ Caution In case of cleaning the oil seal with cleaning oil, please wipe off the cleaning oil immediately. Roller・Cage disassembling points Roller inspection points Confirm no abrasion Confirm no discoloration due to temperature rise Confirm no cracking or chipping Confirm no rust (4) Hold the cage and remove it with the...

Bearing instruction Here is an illustration of how we disassemble, assemble and inspect the bearings. Please follow this for bearing maintenance. Assembling cylindrical roller bearings for backup rolls (1) Complete cleaning of each part before re-assembling. (2) Assemble the bearings in the reverse order of disassembling. (3) Before inserting the inner ring (with shield), supply the initial lubricate oil (mist oil) into the bearing. 【 】 ！ Caution ・ careful to insert only appropriate bearing parts. There are no compatible parts Be with other products. ・ During re-assembly, be careful not to...

Roller・ Cage disassembling points Roller inspection points Confirm no cracking or chipping (2) Hold the cage and remove it with roller (2 rows and 1 row) 【 】 ！ Caution Be sure to keep all rollers and other parts separate from other bearing parts and manage each bearing independently. Confirm no discoloration due to temperature rise Outer ring inspection points Confirm no slipping scratches or brinelling Confirm no cracking or chipping Confirm no discoloration due to temperature rise Confirm no rust Confirm that race way has no unbalanced, asymmetrical roller contact mark on 3 rows Assembling...

< Probable causes> •Slip with the intermediate roll (Sheet jam, involution and so on) <Countermeasures> •Review operating conditions <Countermeasures> •After removing the slipping scratches on outer surface of the outer ring, a minimum of 0.5mm re-grinding on outer ring diameter needs to be done. < Probable causes> • Improper regrinding of outer ring (Heavy grinding, lack of grinding fluid, clogged grinding stone, etc.) <Countermeasures> • Optimizing the grinding conditions, improving grinding stone <Countermeasures> •dispose < Probable causes> •Improper regrinding of outer ring(Clogged...

Raceway roller flaking ・ Rust scratches ・ Rust Raceway flaking Roller flaking ＜Countermeasures＞ ･After use, disassemble and clean as soon as possible ･perform rust prevention maintenance ･confirm the seals condition ＜Countermeasures＞ ･Reusable by lapping using ＜Probable causes＞ ･After use, equipment has been left for a long oil grinding stone or sandpaper period without disassembling ･In case of severe condition, ・ Improper storage condition dispose ・ Intrusion of mill water Scratches ＜Probable causes＞ ･Rolling fatigue service life, excessive loading, improper lubrication ＜Countermeasures＞...

Steel production equipment Applicable multi-roll mill rolls arrangement Note 1) The numbers in parentheses, show necessary bearing quantities per mill. Differences in numbers in parentheses mean it is necessary to use other bearings as well.