Material

ZX-324V11T

Description of the application

A profi led shaft with three slide rails drives several sliding pieces (movable gears) into a packaging machine. Its stroke, transverse to the conveyor belt, has got a range of ± 720°, and moves itself in the axial direction, along the band, for ± 370 mm. The high-torque drive toothing on the outer diameter of the sliding pieces drives a toothed belt. The cycle time for a packaging operation is 0,75 s. During this time, 3/5 units of product are packed. Onto the grooves of the profi led shaft, ZX-530 sliding strips are bonded. The heat dissipation of the plastic-plastic-mating was verifi ed with a calculation. The wear is minimal.  Depending on the machine’s size, three to fi ve sliding pieces are assembled of the profi led shaft of the packaging machine. The profi led shaft is fi x next to the conveyor belt. Through the axial degree of freedom, each sliding piece is enforced to run with the belt and stays always next to the to be packaged product.

Load

The moving weight is 1.5 kg.
The belt pretension force is 100 N.

Problem

The component should be designed, in order to obtain an excellent dynamics, low weight, minimal space requirement and maintenance-free. It must have both the function of a gear and of a linear guide.

Problem-solving

Thanks to the special machining on the inner diameter and the toothing on the outer diameter, the bushing meets the two  requirements: the geometry of the inner diameter provides the axial degree of freedom and the toothing on the outer diameter drives the plunger, which carries the products in their packaging.

Working life

The packaging plant works in two shifts, 220 days per year. The bushing has got a working life of 1,44 x 10^8 cycles, which  corresponds to a duration of approximately 8,5 years.

Advantages

Thanks to the lightweight construction, only
small acceleration forces are required. The
sliding piece needs only a unique lubrication
when assembled.