the cover plate 37 together with the arched ribs 34 form arch shaped air channels 44 interconnecting the air channels 41 and 42 in the second embodiment of the invention as shown in fig4 a sewing machine 60 39 includes a cooling system 52 39 with a flow system disposed on the underside of bottom 29 39 of the oil pan 2 39 between the long sidewalls 25 39 and 26 39 drawn down and the short end wall 27 39 longitudinal ribs the central one of which is marked 45 while the others have the reference symbol 46 in this embodiment a baffle formed by the short end wall 27 39 of oil pan 2 39 serves as the cooling air deflection means the ends 47 of the outer longitudinal ribs 46 facing the short end wall 27 are spaced closer to the short end wall 27 than the ends 47 of the inner longitudinal ribs 46 the end 48 of the longitudinal rib 45 in the center is spaced the furthest apart like the longitudinal ribs 31 and 32 of the first embodiment of the invention the longitudinal ribs 45 and 46 are covered by the cover plate 37 39 thus here again cover plate 37 39 forms a group c of air channels 49 located on the one side of the longitudinal center rib 45 and connected to the air chute 40 39 and a group d of air channels 50 located on the other side of the longitudinal center rib 45 and opposite the cutout 43 in the cover plate 37 furthermore the cover plate 37 together with the bottom 29 the short sidewall 27 and the ends 47.