A shaft-hub connection of a double gearwheel (2) on a transmission shaft (5), in which the double gearwheel (2) has a first gearwheel (3) and a second gearwheel (4), which are connected to one another in a rotationally fixed manner. The shaft-hub connection is in the form of a shrink fit (7) between a hub (8) of the first gearwheel (3) and the transmission shaft (5). A maximum of the torque to be transmitted can be transmitted by virtue of the shrink fit (7).

A connecting device for a chainring of a bicycle is disclosed, including a connecting disc, a shaft, and a crank. The connecting disc is adapted to be engaged with a chainring, and has an axial bore, a bulging portion bulging from a central portion of the connecting disc, and a surrounding portion, which is flat, and surrounds an outer periphery of the bulging portion. The shaft passes through the axial bore to be fixedly engaged with the connecting disc. The shaft has a connecting end. The crank has a connecting end engaged with the connecting end of the shaft, and a bearing end adapted to bear an external force to make the crank rotate around the shaft. Whereby, the amount of materials used to make the connecting device is decreased. At the same time, the manufacturing cost, the size, and the weight of the connecting device are all reduced.

A connecting device for a chainring of a bicycle is disclosed, including a connecting disc, a shaft, and a crank. The connecting disc is adapted to be engaged with a chainring, and has an axial bore, a bulging portion bulging from a central portion of the connecting disc, and a surrounding portion, which is flat, and surrounds an outer periphery of the bulging portion. The shaft passes through the axial bore to be fixedly engaged with the connecting disc. The shaft has a connecting end. The crank has a connecting end engaged with the connecting end of the shaft, and a bearing end adapted to bear an external force to make the crank rotate around the shaft. Whereby, the amount of materials used to make the connecting device is decreased. At the same time, the manufacturing cost, the size, and the weight of the connecting device are all reduced.

A drive shaft is for selectively connecting a drive input to an output. The drive shaft has a tubular portion, a first diaphragm member, and a second diaphragm member displaced axially along the shaft from the first diaphragm member. The first and second diaphragm members each are formed with two axial ends. At least one undulation extends radially of the ends. The tubular portion connects the first and second diaphragm members. The first and second diaphragm members and the tubular portion are formed of fiber-reinforced polymer matrix composites. The first and second diaphragm members are connected to first and second axial ends of the tubular portion through a mechanical connection at joints. There is also a method of forming a drive shaft.

A method for manufacturing a torque-transmitting assembly includes turning an inner component and machining an outermost surface of the inner component such that the outermost surface of the inner component has a continuous convex shape. The method further includes turning an external component and machining an innermost surface of the external component such that the innermost surface of the external component has a continuous convex shape. The method also includes heating the innermost surface of the external component to expand a size of the innermost surface after machining the innermost surface of the external component and placing the heated external component onto the inner component while the inner component is maintained at room temperature.

A method for manufacturing a torque-transmitting assembly includes turning an inner component and machining an outermost surface of the inner component such that the outermost surface of the inner component has a continuous convex shape. The method further includes turning an external component and machining an innermost surface of the external component such that the innermost surface of the external component has a continuous convex shape. The method also includes heating the innermost surface of the external component to expand a size of the innermost surface after machining the innermost surface of the external component and placing the heated external component onto the inner component while the inner component is maintained at room temperature.

An exhaust-gas turbocharger (1) having a shaft (2), a turbine wheel (5), which is fastened to the shaft (2), and a heat throttle (8) between the shaft (2) and the turbine wheel. An end face (3) of the shaft (2) is provided with a protrusion (4), with an outside diameter (A.sub.4) which is smaller than the outside diameter (A.sub.2) of the shaft (2). The turbine wheel (5) has a hollow receiving portion (7), which is formed integrally on the wheel rear side (6) and the inside diameter (I.sub.7) corresponds to the outside diameter (A.sub.4) of the protrusion (4) and the outside diameter (A.sub.7) corresponds to the outside diameter (A.sub.2) of the shaft (2). The protrusion (4) engages into the receiving portion (7). The heat throttle (8) is formed by a cavity (8A, 8B), which has an outside diameter (A.sub.8) which is smaller than the outside diameter (A.sub.4) of the protrusion (4) and extends from the protrusion (4) into the receiving portion (7).

An exhaust-gas turbocharger (1) having a shaft (2), a turbine wheel (5), which is fastened to the shaft (2), and a heat throttle (8) between the shaft (2) and the turbine wheel. An end face (3) of the shaft (2) is provided with a protrusion (4), with an outside diameter (A.sub.4) which is smaller than the outside diameter (A.sub.2) of the shaft (2). The turbine wheel (5) has a hollow receiving portion (7), which is formed integrally on the wheel rear side (6) and the inside diameter (I.sub.7) corresponds to the outside diameter (A.sub.4) of the protrusion (4) and the outside diameter (A.sub.7) corresponds to the outside diameter (A.sub.2) of the shaft (2). The protrusion (4) engages into the receiving portion (7). The heat throttle (8) is formed by a cavity (8A, 8B), which has an outside diameter (A.sub.8) which is smaller than the outside diameter (A.sub.4) of the protrusion (4) and extends from the protrusion (4) into the receiving portion (7).

A welding method for an outer joint member of a constant velocity universal joint includes constructing a cup section having track grooves, which engage with torque transmitting elements, formed along an inner periphery thereof and a shaft section that is formed on a bottom portion of the cup section by two or more separate members, joining a cup member forming the cup section and a shaft member forming the shaft section, and melt-welding end portions of the cup member and the shaft member. The cup member and the shaft member are shaped so that a sealed hollow cavity portion is formed when the end portions of the cup member and the shaft member are brought into abutment against each other, the melt-welding of the end portions being performed when the sealed hollow cavity portion is under atmospheric pressure or lower.

A welding method for an outer joint member of a constant velocity universal joint includes constructing a cup section having track grooves, which engage with torque transmitting elements, formed along an inner periphery thereof and a shaft section that is formed on a bottom portion of the cup section by two or more separate members, joining a cup member forming the cup section and a shaft member forming the shaft section, and melt-welding end portions of the cup member and the shaft member. The cup member and the shaft member are shaped so that a sealed hollow cavity portion is formed when the end portions of the cup member and the shaft member are brought into abutment against each other, the melt-welding of the end portions being performed when the sealed hollow cavity portion is under atmospheric pressure or lower.