The composite camshaft is still gaining ground in the marketplace. The main reason for this is the considerable weight reduction it brings, compared to its one-piece rival. The composite version is by now also widely used in the HGV sector. However, the main disadvantage of many current assembly processes is the high joining force applied, which creates unacceptable tolerances in positioning and alignment of the cams. By contrast, the patented heat shrink assembly process from EMAG offers a decisive advantage, as it ensures that “ready-to-fit“ camshafts, gear shafts and other precision composite units can be produced without problems.
The advantages of the composite camshaft are well known: less expense, less weight, the possibility to use different materials for the various constituent components, greater flexibility in production and the ability to implement new cam geometries, such as negative radii, with ease. The necessary reduction in fuel consumption – and with it those of CO2 emissions – are easier to achieve with an increasing use of composite camshafts.
Alternative processes for the joining of cam and shaft have one serious disadvantage: the two components cannot be joined with the necessary accuracy to avoid a subsequent finish grinding process. In many cases, the joining of cam to tube is carried out using a form-fit process like press-fitting, knurling and/or spline/serrated gearing. The joining forces required for these processes can deform the components and result in unacceptable tolerances in cam position and orientation.