A method for forming features in an exterior surface of a heat transfer tube includes forming a plurality of channels into the surface, where the channels are substantially parallel to one another and extend at a first angle to a longitudinal axis to the tube. A plurality of cuts are then made into the surface substantially parallel to one another and extend at a second angle to a longitudinal axis to the tube different from the first angle. Individual fin segments extend from the surface and are separated from one another by the channels and the cuts. The fin segments have a first channel-adjacent edge adjacent substantially parallel to the channel, a first cut-adjacent edge substantially parallel to the cut, and a corner formed by a second channel-adjacent edge and a second cut-adjacent edge. A tube formed using this method can be used as a condenser tube.

The invention relates to a steering shaft (1) for a vehicle, and to a method for producing a steering shaft of this type. The steering shaft (1) comprises a tubular shaft body (10) which extends along the longitudinal axis (L) and has a first shaft end (11) and a second shaft end (12), a bending section (13) being arranged between the first shaft end (11) and the second shaft end (12), the bending section (13) having a plurality of grooves (21, 22, 23, 24) which run in the circumferential direction of the shaft body (10) for the formation of a groove structure, characterized in that the groove structure is of non-uniform configuration in the direction of the longitudinal axis (L).

A helically wound tubular structure is disclosed. The tubular structure has a first sheet metal helically wound about a longitudinal axis, a second sheet metal having voids disposed therein helically wound about the longitudinal axis and coaxially about the first sheet metal, and a third sheet metal helically wound about the longitudinal axis and coaxially about the first sheet metal and the second sheet metal.

A tubular structure is disclosed. The tubular structure has a first sheet metal having a machine direction. The first sheet metal is convolutely wound about a longitudinal axis and has a tail portion. The tail portion of the first sheet metal is disposed upon and bonded to an immediately subjacent convolution of the first sheet metal.

An elongate tubular structure is disclosed. The elongate tubular structure has a first and second tubular structure wherein a first end of the first tubular structure is matingly and fasteningly engaged to a first end of the second tubular structure. The first and second tubular structures each have a first sheet metal having a machine direction being convolutely wound about a first longitudinal axis. The first sheet metal has a tail portion that is disposed upon and bonded to an immediately subjacent convolution of the first sheet metal to form the respective first and second tubular structures.

A method for forming features in an exterior surface of a heat transfer tube includes forming a plurality of channels into the surface, where the channels are substantially parallel to one another and extend at a first angle to a longitudinal axis to the tube. A plurality of cuts are then made into the surface substantially parallel to one another and extend at a second angle to a longitudinal axis to the tube different from the first angle. Individual fin segments extend from the surface and are separated from one another by the channels and the cuts. The fin segments have a first channel-adjacent edge adjacent substantially parallel to the channel, a first cut-adjacent edge substantially parallel to the cut, and a corner formed by a second channel-adjacent edge and a second cut-adjacent edge. A tube formed using this method can be used as a condenser tube.

An exterior surface of a heat transfer tube has a plurality of channels formed into the surface, where the channels are substantially parallel to one another and extend at a first angle to a longitudinal axis to the tube. A plurality of cuts are then made into the surface substantially parallel to one another and extend at a second angle to a longitudinal axis to the tube different from the first angle. Individual fin segments extend from the surface and are separated from one another by the channels and the cuts. The fin segments have a first channel-adjacent edge adjacent substantially parallel to the channel, a first cut-adjacent edge substantially parallel to the cut, and a corner formed by a second channel-adjacent edge and a second cut-adjacent edge. The tube can be used as a condenser tube.

A method for forming features in an exterior surface of a heat transfer tube includes forming a plurality of channels into the surface, where the channels are substantially parallel to one another and extend at a first angle to a longitudinal axis to the tube. A plurality of cuts are then made into the surface substantially parallel to one another and extend at a second angle to a longitudinal axis to the tube different from the first angle. Individual fin segments extend from the surface and are separated from one another by the channels and the cuts. The fin segments have a first channel-adjacent edge adjacent substantially parallel to the channel, a first cut-adjacent edge substantially parallel to the cut, and a corner formed by a second channel-adjacent edge and a second cut-adjacent edge. A tube formed using this method can be used as a condenser tube.

A method for forming features in an exterior surface of a heat transfer tube includes forming a plurality of channels into the surface, where the channels are substantially parallel to one another and extend at a first angle to a longitudinal axis to the tube. A plurality of cuts are then made into the surface substantially parallel to one another and extend at a second angle to a longitudinal axis to the tube different from the first angle. Individual fin segments extend from the surface and are separated from one another by the channels and the cuts. The fin segments have a first channel-adjacent edge adjacent substantially parallel to the channel, a first cut-adjacent edge substantially parallel to the cut, and a corner formed by a second channel-adjacent edge and a second cut-adjacent edge. A tube formed using this method can be used as a condenser tube.

A helically wound tubular structure formed from helically wound sheet metals is disclosed. The tubular structure has a first sheet metal helically wound about a longitudinal axis. A second sheet metal having voids disposed therein is helically wound about the longitudinal axis and coaxially about the first sheet metal. A third sheet metal is helically wound about the longitudinal axis and coaxially about the first sheet metal and the second sheet metal.