Precise height adjustment in rail grinding machines

What was needed: Linear axes for precise grinding depth adjustment and for optimising transverse movements.

Requirements: High accuracy, low clearances, lubrication-free and low-maintenance systems for lifting, lowering and transverse movements.

Industry: Railway technology

Customer success: The linear axes in the ZAK grinding machines' lifting and lowering mechanism ensure precise grinding depth adjustment and minimise clearances in the system. Through the use of lubrication-free components, maintenance requirements have been reduced and the machines' performance increased. Further developments with new solutions for transverse movements promise additional weight reduction and durability.

The Polish manufacturer KARYA sp. z o.o. based in Lublin develops grinding machines such as the two models ZAK-1P and ZAK-2, which are used for the precise machining of rails and points in the railway and tram sector. In the course of production, KARYA faced several challenges: to achieve a consistently high grinding quality, precise grinding depth adjustment was necessary – even with changing inclination angles of the grinding wheel in a range of -60 to +60 degrees. Earlier solutions with multiple splined shafts showed clearances that could impair accuracy.

In addition, it was essential to find a durable and low-maintenance solution to minimise downtime during intensive machine operation. Reliable mechanical components are crucial, particularly when grinding rails, as the components are subjected to intense sparking and mechanical loads. In addition to the main movements of the grinding unit, the transverse movement of the system should also be improved in order to save weight and further increase the service life.

To meet the high requirements of the ZAK grinding machines, linear axes of the type SLW-2080 were integrated into the lifting and lowering mechanism of the grinding units. These components allow for precise adjustment of the grinding depth to ensure precise rail machining. Thanks to the design of the linear axes, the previously occurring clearance could be eliminated to improve grinding accuracy.

The axes are particularly robust, completely lubrication-free and maintenance-free, which proves their durability in a demanding environment such as rail grinding. Additional covers were attached to the guides to protect the mechanism from sparks during the grinding process.

Optimisation work is currently underway to improve the transverse movement of the grinding unit. Planned innovations involving lubrication-free and lightweight igus components are intended to ensure weight reduction and an extended service life.