A drive shaft body extends between axial ends and has an outer peripheral surface with undulations extending between relatively greater and smaller outer diameters. The undulations extend along a non-zero angle relative to a circumferential direction defined relative to a drive axis of the drive shaft. The undulations extend along a spiral. The drive shaft body is formed of a fiber-reinforced composite material.

An assembly has a radial ball bearing including a bearing inner ring, and a rotatable shaft with a shaft end region with a bearing seat. The bearing seat has a shoulder on one side, on which the bearing inner ring of the radial ball bearing is seated for supporting the shaft. The bearing seat is shortened in the longitudinal direction relative to the radial ball bearing, and extends toward a height of the radial ball bearing. The bearing seat terminates at a distance (L) from an orthogonal projection from the proximalmost points of a distalmost row of balls onto the bearing seat surface such that L=k*D, wherein k is in a range between 0.7 and 0.5.

An assembly has a radial ball bearing including a bearing inner ring, and a rotatable shaft with a shaft end region with a bearing seat. The bearing seat has a shoulder on one side, on which the bearing inner ring of the radial ball bearing is seated for supporting the shaft. The bearing seat is shortened in the longitudinal direction relative to the radial ball bearing, and extends toward a height of the radial ball bearing. The bearing seat terminates at a distance (L) from an orthogonal projection from the proximalmost points of a distalmost row of balls onto the bearing seat surface such that L=k*D, wherein k is in a range between 0.7 and 0.5.

A shaft connection 1 for a longitudinal shaft assembly, has at least a first shaft having a first and second ends, and a second shaft, disposed so as to be coaxial with the first shaft, having first and second ends; the shafts extending axially. The first end forms a hollow portion. The first shaft end forms a first journal having a displacement portion. The first shaft end at least in an initial position of the shaft connection extends through the hollow portion which axially by the displacement portion forms a guide portion and circumferentially forms a form-fitting first connection. In the initial position a mutual axial displacement of the first and second shafts is prevented by an axial securing feature. In a crash the axial securing feature; is releasable by an axial release force. The first shaft is axially displaceable relative to the second shaft.

An easily inspected shaft assembly is provided and includes a shaft, a sleeve receptive of a portion of the shaft and an optically activatable layer including first and second sections disposed on respective exterior surfaces of the shaft and the sleeve, respectively, such that the first and second sections move relative to one another as the shaft and the sleeve move relative to one another.

A rotating shaft for a rotary machine includes a first shaft portion centered on a central axis and a variable lattice structure in an interior of the rotating shaft. The variable lattice structure includes a first region of the rotating shaft having a first lattice structure and a second region of the rotating shaft having a second lattice structure. The second lattice structure of the second region is denser than the first lattice structure of the first region. The second region is a deflection region or a stress region of the rotating shaft.

A drive shaft (1, 3) for use with a rotation device (10, 20) includes an outer layer (11, 31) and an inner layer (12, 32). The outer layer is a tubular structure, and the inner layer is accommodated in a space defined by the outer layer and defines a central lumen (13, 33) for receiving therein an external mechanism. The outer layer is rotatable about the central lumen, and the inner layer is rollable relative to both the outer layer and the external mechanism and thus allows rolling friction to occur between the drive shaft and the external mechanism. Such a structure of the drive shaft can reduce friction between the drive shaft and a guidewire as well as loss due to such friction, avoiding failure of the guidewire due to excessive friction between the guidewire and the drive shaft. Therefore, it is ensured that the drive shaft is suitable for use with guidewires commonly used in clinical practice, resulting in improved surgical operability and lower surgical cost. Also disclosed is a rotation device including an instrument (2, 4) and the drive shaft. The instrument is disposed at one end of the drive shaft and is coupled to the outer layer of the drive shaft so as to be able to be driven by the outer layer to rotate.

A forced induction device (100) includes: a rotor (1) which includes a turbine side shaft portion (11), a compressor side shaft portion (12), and a connection shaft portion (13) connecting these to each other; a turbine side bearing (5) which supports the turbine side shaft portion (11); and a compressor side bearing (6) which supports the compressor side shaft portion (12). A rigidity of the connection shaft portion (13) is lower than that of the turbine side shaft portion (11) and the compressor side shaft portion (12) so that a node in a mode shape at each critical speed involving with an operating rotational speed region of the rotor (1) is located between the turbine side bearing (5) and the compressor side bearing (6).

A forced induction device (100) includes: a rotor (1) which includes a turbine side shaft portion (11), a compressor side shaft portion (12), and a connection shaft portion (13) connecting these to each other; a turbine side bearing (5) which supports the turbine side shaft portion (11); and a compressor side bearing (6) which supports the compressor side shaft portion (12). A rigidity of the connection shaft portion (13) is lower than that of the turbine side shaft portion (11) and the compressor side shaft portion (12) so that a node in a mode shape at each critical speed involving with an operating rotational speed region of the rotor (1) is located between the turbine side bearing (5) and the compressor side bearing (6).

A turbocharger shaft includes a connection portion at a connection with a wheel of the turbocharger. The shaft includes a stainless steel cladding at least along one or more grooves of the connection portion to reduce the risk of cold cracking and bending fatigue.