EMAG offers multiple grinding solutions for transmission shafts
Technological advances in automotive engineering are rapidly changing the demand for production technology for new processes and the established processes like cylindrical or modular grinding of transmission shafts. Many components, to meet the changing needs, have complex geometric details to be done with very high precision. Manufacturing companies depend on mechanical engineering firms like EMAG to develop individualised grinding solutions for the shafts – ideally, integrated into complete production lines. The grinding specialists from the EMAG Group have developed solutions like the HG 208 horizontal cylindrical grinder, which is ideal for the precision machining of shafts in series production. With its modular design principle, these machines can be adapted to a wide variety of machining tasks and integrated into EMAG production lines.
Off the shelf grinding solutions are virtually impossible for many applications. Drive shafts for electric motors, complex camshafts or crankshafts as well as transmission shafts all require very different processes. Different solutions are required depending on the necessary grinding operation – single, multiple, parallel or combined internal and external. The component and applied grinding technology may demand technologies like in-process measuring devices, dressing units for CBN and corundum grinding wheels, automatic balancing units and more.
“It is these very different demands that characterise the development of the HG 208 horizontal cylindrical grinder,” Guido Hegener, Managing Director of EMAG Maschinenfabrik, headquartered in Salach, Germany. “We offer our customers a wide range of different technology modules that can be easily integrated into a standardised machine. The HG 208 can be equipped with 1 or 2 compound slides, on each of which different external and internal grinding spindles can be fitted. By using a B-axis or a centre drive, we can provide the perfect solution for each customer-specific application,” he added.
Continuously variable transmission (CVT) vindicates how developments in the automotive industry can influence and drive forward flexible manufacturing concepts. This technology is being used in modern hybrid drives, effectively combining the power of combustion engines and electric motors. The central or primary CVT shaft represents a real grinding challenge in the production process. On the one hand, the control wheel surface is precisely machined by an angle plunge. On the other hand, axial ball track grooves have to be machined.
With EMAG, both processes are performed in a single clamping operation to avoid reclamping errors and to achieve increased precision. For machining the grooves, the grinder is equipped with a dressable ceramic CBN grinding wheel. With its perfect dressing system, the quality of the ball track stays high.
For machining the taper face on the primary shaft (and similar surfaces on other shafts) EMAG has recently expanded its HG modular system: A corundum grinding wheel with a maximum diameter of 750 mm (29.5 inches) is used for this task. “This example illustrates how we continually adapt the machine and the available modules to the conditions imposed by the various components. This allows us to create the perfect technology configuration for the customer: a large corundum grinding wheel for external machining and a small CBN grinding wheel for machining the grooves, arranged on 2 separate slides with their separate dressing systems. This ensures that the requirements for quality and cycle times are met,” he said.
EMAG production lines
Another important factor for production planners in the automotive industry is the holistic approach from EMAG. The mechanical engineering company masters all processes for soft and hard machining and has extensive experience in the establishment of complete production solutions. For example, a transmission shaft is pre-processed on EMAG VTC vertical turning centres and finished on HG series grinders. With the associated line automation, EMAG completely adapts itself to customer requirements.
“The HG 208 has been on the market for around 15 years already – this means customer’s benefit from a technology that is well established, but which continues to intelligently expand to cover a variety of fields of application,” Hegener said. With these updates, the HG 208 can successfully perform cylindrical grinding operations on crankshafts and camshafts. Parallel external and internal machining of hollow shafts is also made possible with this concept. For this purpose, there is a variant of the HG 208 with a direct-driven centre drive.
EMAG grinding experts see a great opportunity in the growing electric vehicle market for the HG 208 and its associated product lines, due to its efficient grinding operation of the central drive shaft for such vehicles.
EMAG’s HG 208
A grinding spindle for corundum grinding wheels up to 750 millimeters (29.5 inches) in diameter
Guido Hegener, Managing Director of EMAG Maschinenfabrik.