the inside diameter 44 of the locking sleeve 29 so that the socket wrench 27 can be rotatably arranged in the locking sleeve 29 the outer surface of the locking sleeve 29 is provided with an external hexagon 46 which interacts with the internal hexagon 43 of the bush 42 and respectively with the internal hexagon 28 of the hub 16 of the compressor wheel 14 fig4 the outside diameter 45 of the socket wrench 27 corresponds over part of its length with the through bore 20 of the hub 16 in addition the socket wrench 27 has an internal hexagon 47 on its side facing the compressor wheel 14 which internal hexagon 47 corresponds with the external hexagon 26 of the shaft end 19 fig3 if the dismantling of the compressor wheel is necessary or if components arranged further on the inside such as for example the bearings 48 have to be exchanged first of all the filter muffler 36 is removed from the compressor casing 13 then the screws 34 arranged between the air outlet side casing part 33 and the air inlet side casing part 32 are released and the air inlet side casing part 32 including the diffuser 17 is removed fig1 the mounting plate 38 is then screwed up in the tapped holes 37 of the air outlet side casing 33 whereupon the locking sleeve 29 is inserted through the central recess 41 or the bush 42 of the mounting plate 38 into the compressor wheel 14 fig3 fig4 in the process the external hexagon 46 of the locking sleeve 29 comes into engagement with the internal hexagon 28 of the hub 16 and respectively with the internal hexagon 43 of the bush 42 so that the compressor wheel 14 is.