Abstract: Gear wheel that is provided with spokes (17) which extend between a rim (16) supporting a gear mesh (15) and a corresponding gear hub (18), whereby free spaces (19) are located between the spokes (17) which extend between the rim (16) and the gear hub (18), characterised in that at least one of said free spaces (19) is filled with a block (20) made of a rigid, incompressible material, whereby between the gear wheel (10) on the one hand and the block (20) on the other hand a viscoelastic material (21) is located.

Abstract: An element for compressing or expanding a gas including a rigid housing (2) containing an internal chamber; a rotor (3a, 3b) situated in the internal chamber and comprising a rotor shaft (4a, 4b); one or more bearings (7) in which the rotor shaft (4a, 4b) is bearing-supported, wherein the rotor (3a, 3b) with its rotor shaft (4a, 4b) is rotatably mounted with respect to the housing (2) by means of these bearings (7), wherein the rotor (3a, 3b) is mounted with one or more clearances with respect to a wall (5) of the internal chamber, and the element (1) is provided with a separate yielding component (10) which is positionally adjustable with respect to the housing (2) in such a way that at least one of the clearances can be acted upon, wherein the separate yielding component (10) is not directly attached to the rotor (3a, 3b).

Abstract: An element for compressing or expanding a gas including a rigid housing (2) containing an internal chamber; a rotor (3a, 3b) situated in the internal chamber and comprising a rotor shaft (4a, 4b); one or more bearings (7) in which the rotor shaft (4a, 4b) is bearing-supported, wherein the rotor (3a, 3b) with its rotor shaft (4a, 4b) is rotatably mounted with respect to the housing (2) by means of these bearings (7), wherein the rotor (3a, 3b) is mounted with one or more clearances with respect to a wall (5) of the internal chamber, and the element (1) is provided with a separate yielding component (10) which is positionally adjustable with respect to the housing (2) in such a way that at least one of the clearances can be acted upon, wherein the separate yielding component (10) is not directly attached to the rotor (3a, 3b).

Abstract: A piston compressor, comprising at least one piston compressor element (3) that is provided with a housing (8) with a compression chamber (13) in which a piston (10) is arranged movably back and forth in an axial direction (X-X?) between an upper dead point and a lower dead point by means of a drive shaft (5) driven by a rotary motor (6), and in which between this drive shaft (5) and the piston (10), a kinematic transmission (20) is provided for the primary drive of the piston (10), characterized in that the piston (10) is provided with a complementary drive (25) in the form of an electromagnetic linear drive.