One of the key parameters when assembling the right wheel is the load capacity. What might at first appear to be a simple parameter does, in practice, present some challenges.
For industrial wheels, the load capacity is, by definition, specified at speeds of 4 to 16 km/h.
It is the manufacturer’s responsibility to determine the load capacity, based on the above-mentioned factors. Vulkoprin has a lot of experience and is equipped with a modern test stand to carry out simulations and tests.
Consult the ‘Vulkoprin Wheel’ team for an accurate analysis of the load capacity.
Load capacity - influences
The load capacity of a wheel is influenced by:
- The dimensions: the diameter and the width have a significant influence on which load the wheel can bear.
- The shape factor: due to the shape factor, a wheel with a thick elastomer cover will deform more than a wheel with a thin elastomer cover.
- The modulus: the stiffness of the elastomer that is used will determine how much the cover deforms under load. The hardness, expressed in Shore A, of the elastomer correlates well with the elasticity modulus. A hard elastomer will impress less than a soft elastomer (comparable to a hard or less hard inflated bicycle tyre).
- The speed and time period: all elastomers exhibit viscoelastic behaviour. This means that some of the energy required to deform the cover under load is not recovered after relieving the load. This creates a rolling resistance and a heating of the elastomer. The size, frequency and duration of the deformity determine how much energy is pumped into the wheel. When this quantity exceeds a critical limit the elastomer will have a thermal defect.
- The wheel centre and the bearings of the wheel also affect, besides the cover, the load capacity.
- The setup of the wheels is important when choosing the load capacity.
- The surrounding factors like high shock loads, ambient temperature and a warm runway reduce the load capacity of the wheel.
- The friction on swivel castors and traction wheels also reduce the load capacity.