A lubrication ring for a mechanical expander (1) for sizing large pipes comprises a conventionally manufactured ring (12) made of steel, in particular construction steel. Fluid bores are provided in the ring (12). A part (13) of the lubrication ring (6) is manufactured by an additive manufacturing technology.

Some embodiments disclosed herein are directed to a tubular member including a central axis, a first end, a second end opposite the first end, an upset region between and axially spaced from the first end and the second end, and a first outer diameter axially spaced midway between the first end and the upset region. The upset region includes a second diameter which is larger than the first diameter, does not include a weld joint, and includes redistributed material from the tubular member.

Some embodiments disclosed herein are directed to a tubular member including a central axis, a first end, a second end opposite the first end, an upset region between and axially spaced from the first end and the second end, and a first outer diameter axially spaced midway between the first end and the upset region. The upset region includes a second diameter which is larger than the first diameter, does not include a weld joint, and includes redistributed material from the tubular member.

A method for joining members according to the present invention includes: providing a first member, a second member, a guide shaft member, a rubber member, a first plunger, a second plunger, and a drive mechanism; inserting the second member into a hole portion of the first member; inserting the guide shaft member into a through-hole of the rubber member; inserting the rubber member, into which the guide shaft member is inserted, inside the second member; arranging an assembly in which the first member, the second member, the rubber member, and the guide shaft member so as to horizontally extend; arranging the assembly so as to be sandwiched by the first plunger and the second plunger; and moving the second plunger toward the first plunger; compressing the rubber member by the first plunger and the second plunger in a direction where the guide shaft member extends, and expanding the rubber member radially outside the guide shaft member; and thus expanding and deforming at least a portion of the second member that is inserted into the hole portion to join the portion to the first member by press-fitting.

A method for joining members according to the present invention includes: providing a first member, a second member, a guide shaft member, a rubber member, a first plunger, a second plunger, and a drive mechanism; inserting the second member into a hole portion of the first member; inserting the guide shaft member into a through-hole of the rubber member; inserting the rubber member, into which the guide shaft member is inserted, inside the second member; arranging an assembly in which the first member, the second member, the rubber member, and the guide shaft member so as to horizontally extend; arranging the assembly so as to be sandwiched by the first plunger and the second plunger; and moving the second plunger toward the first plunger; compressing the rubber member by the first plunger and the second plunger in a direction where the guide shaft member extends, and expanding the rubber member radially outside the guide shaft member; and thus expanding and deforming at least a portion of the second member that is inserted into the hole portion to join the portion to the first member by press-fitting.

A bead forming method includes the steps of preparing a bumper stay having a partition wall that partitions an internal space and extends in a longitudinal direction, an elastic body that can be inserted into the bumper stay, and a pusher that presses the elastic body; inserting the elastic body into the bumper stay and arranging the elastic body in the bumper stay so as not to come into contact with the partition wall; and forming a buckling bead by compressing the elastic body in the longitudinal direction of the bumper stay by the pusher to expand the elastic body outward in a radial direction without coming into contact with the partition wall, thereby bulging a part of an outer wall of the bumper stay outward in the radial direction without deforming the partition wall.

A bead forming method includes the steps of preparing a bumper stay having a partition wall that partitions an internal space and extends in a longitudinal direction, an elastic body that can be inserted into the bumper stay, and a pusher that presses the elastic body; inserting the elastic body into the bumper stay and arranging the elastic body in the bumper stay so as not to come into contact with the partition wall; and forming a buckling bead by compressing the elastic body in the longitudinal direction of the bumper stay by the pusher to expand the elastic body outward in a radial direction without coming into contact with the partition wall, thereby bulging a part of an outer wall of the bumper stay outward in the radial direction without deforming the partition wall.

A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion. Thus, effects such as improving the precision with which the side wall portion of the case, the heat transfer tube, and a connecting tube are fitted to each other can be achieved, and as a result, the respective parts can be brazed easily and appropriately.

A heat exchanger includes a tube expansion portion formed by expanding a heat transfer tube so that an outer peripheral surface of the heat transfer tube is pressed against an inner peripheral surface of a hole provided in a side wall portion of a case. The tube expansion portion includes first and second bulge portions positioned respectively on the inside and the outside of the side wall portion so as to sandwich the side wall portion in an axial length direction of the heat transfer tube and configured such that respective outer peripheral surfaces thereof partially bulge outward in a radial direction of the heat transfer tube, an end portion tip end of the heat transfer tube is positioned apart from the second bulge portion, and the end portion tip end and a part in the vicinity thereof are expanded so as to be included in a part of the tube expansion portion. Thus, effects such as improving the precision with which the side wall portion of the case, the heat transfer tube, and a connecting tube are fitted to each other can be achieved, and as a result, the respective parts can be brazed easily and appropriately.

A heat exchanger includes tube expansion portions provided respectively on a plurality of heat transfer tubes such that outer peripheral surfaces of the heat transfer tubes are respectively pressed against inner peripheral surfaces of a plurality of first holes provided in a side wall portion of a case, and a plurality of first concave surface portions provided in an outer surface of the tube expansion portion so that first gaps, into which brazing material of a first brazed portion advances, are formed between the outer surface of the tube expansion portion and the inner peripheral surface of the first hole. At least one of the plurality of first concave surface portions is positioned in an outside peripheral surface portion of the outer peripheral surface of the heat transfer tube. According to this configuration, the strength with which the heat transfer tubes are attached to the case can be increased while simplifying a manufacturing operation and reducing the manufacturing cost.