Abstract: A turbomolecular pump is disclosed which has reduced axial length so as to provide a small-sized pump, and which also has improved stability during high-speed operation, is simple in construction, and is able to operate at much higher speeds than prior art devices.

Abstract: An improved Stirling engine has a piston and a crosshead slidably disposed inside a cylinder and secured to one another by a piston rod so as to reciprocate as a single body with a space formed between the crosshead and the piston. An oil-deflecting guard for deflecting oil which is scattered by the movement of the crosshead is disposed between the crosshead and the piston and is supported so as to move with the crosshead. A first oil-absorbing member for absorbing oil which enters the space above the oil-deflecting guard is disposed on the oil-deflecting guard on the piston side thereof. A second oil-absorbing member is disposed between the first oil-absorbing member and the piston with a space therebetween. The space between the crosshead and the piston can be connected with the inside of a crankcase by oil drainage holes.