Material handling refers to the transport of goods and merchandise within storage areas. This requires highly specialised and sophisticated technology to be built into industrial trucks such as order pickers, counterbalance forklifts, high- and low-lift trucks or very narrow aisle trucks. The hydraulics of vehicles in this field differ in their design and requirements from those in other applications, such as construction or agricultural vehicles. One important factor is that about 80 % of the vehicles are already electrically powered, and that number is growing. Moreover, it can be expected that this share will increase considerably in material handling over the next ten years.
The focus is shifting towards the various energy systems in which lithiumion batteries have taken up a significant share and are being used more and more. Until now, lead-acid batteries have been widely used, but they are significantly inferior to lithium-ion batteries in terms of their charging time, performance, lifespan, sustainability and compactness. The latter factor is crucial because a compact design is essential in this sector. In industrial trucks, the entire drive technology has to fit into a very small space, with the trend being towards ever more compact vehicles. At the same time, the compact build must not be at the expense of performance and safety, continually presenting manufacturers and developers with great challenges.
Sustainability through energy recovery
Sustainability is a hot topic – not just in the hydraulics industry – both in terms of the components and technologies used as well as throughout the entire supply chain. In addition to common sustainability measures, the field of material handling can set new standards in energy recovery. The challenge is to recover the maximum amount of energy from movements that only last a few seconds. In high rack stackers, for example, this is accomplished when braking or lowering loads. The action of the hydraulic pump that normally supplies the volume flow for lifting is reversed, causing it to act as a motor. At the same time, the electric motor serves as a generator that recharges the battery. Up to 20 % of the applied energy can be recovered in this way. From a technical point of view, a higher degree of recovery is certainly possible, although this can lead to increased development effort as well as considerable costs. It can be expected that the costs will go down and the recovery rates will also become economically viable as the development work progresses.
