A keying device of this kind is disclosed, for example, in European Patent EP-A-0 065 585.
In this arrangement, the spacing bush constitutes a friction element adapted to rotate with the shaft and the rotor of the motor. In order for this to occur, the bush is clamp fitted on the shaft and the sleeve connected to the rotor. However, the spacing bush must still be able to slide axially on the shaft to enable keying and adjustment of the axial clearance during assembly of the motor. The need to permit axial sliding of the spacing bush may lead to a mounting which is inadequately clamped to provide sufficient connection in rotation and in translation between the spacing bush, on the one hand, and the shaft and rotor of the motor, on the other hand.
Conversely, clamped mounting of the bush to ensure connection in rotation may make axial sliding difficult.
To provide efficient connection between the spacing bush and the rotor, as well as with the shaft, use of a filling material, which can be hardened, disposed between the bush and the rotor has been proposed (see German patent No. DE-A-1 538 921). However, supplying the correct quantity of material to be inserted is difficult, since the axial clearance to be taken up is not known exactly, so that the effectiveness of the connection which is made with the material which can subsequently be hardened is not always optimal.
The primary object of the invention is to provide a device for axially keying the rotor of a rotating machine of the kind defined previously, which responds better than those currently available to the various requirements in practice and which, in particular, enables better use of the material bonding the shaft, the sleeve of the insulating disc and the spacing bush.