The present invention relates to a rotor of the self-supporting type for a turbo-machine. The rotor has no main shaft therethrough, but instead comprises a plurality of blade-carrying discs which are held together by axial bolts and are mutually guided by spacing rings only. This construction is above all intended for multi-stage machines, the discs in the rotor described being provided with central holes which leave free space for a through shaft of another stage in the turbomachine.
In turbo-machines of this kind, great demands are made on the guiding of the discs by the spacing rings, especially in large machines where the dead weight of the rings causes great stresses in the rings because of the rotational forces. In order to limit the elongation in the rings and thus avoid play between these and the circular edges of the discs, the rings must have a sufficient cross-sectional area. However, there must be taken into consideration that an increase in this cross-sectional area will also increase the dead weight of the rings and therefore the rotational forces.