Provided is a welding method enabling enhancement of quality of welding between an upper plate and a lower plate. One aspect of the present disclosure is the welding method including welding the upper plate and the lower plate overlapped with the upper plate by irradiating a surface of the upper plate with a laser beam. The welding includes: forming an auxiliary welding path that is continuous and includes a reciprocating or circling path; and forming a main welding path that intersects a welding advancing direction and that includes turning points, after formation of the auxiliary welding path.

Provided is a welding method enabling enhancement of quality of welding between an upper plate and a lower plate. One aspect of the present disclosure is the welding method including welding the upper plate and the lower plate overlapped with the upper plate by irradiating a surface of the upper plate with a laser beam. The welding includes: forming an auxiliary welding path that is continuous and includes a reciprocating or circling path; and forming a main welding path that intersects a welding advancing direction and that includes turning points, after formation of the auxiliary welding path.

A laser welding method is provided to ensure a sufficient joining strength between metal plates by increasing the area of a joining region while preventing “burn through” of a molten metal. In the laser welding method by applying a laser beam to a surface of multiple metal plates superimposed on each other, a scanning locus with the laser beam is sequentially shifted from an inner circular scanning locus to an outer one in a predetermined joining region on the metal plates, and an emission interval is provided to temporally stop the metal-plate-surface irradiation when the scanning locus is shifted. Thus, every time the scanning locus is shifted, the molten metal due to the previous irradiation is cooled and increases its viscosity. Accordingly, the “burn through” is prevented regardless of increase of the area of the joining region, which results in a sufficient joining strength between the metal plates.

A piston for an internal combustion engine and a method for producing a piston are disclosed. The piston includes an upper piston part and a lower piston part that together delimit a circumferential cooling channel for receiving a cooling medium both radially inside and radially outside. The upper piston part and the lower piston part are connected to one another via a radially outer weld connection and a radially inner weld connection. The radially outer weld connection includes a radially outer weld bead that projects radially inwards into the cooling channel for forming a deflection element for the cooling medium received in the cooling channel.

A piston for an internal combustion engine and a method for producing a piston are disclosed. The piston includes an upper piston part and a lower piston part that together delimit a circumferential cooling channel for receiving a cooling medium both radially inside and radially outside. The upper piston part and the lower piston part are connected to one another via a radially outer weld connection and a radially inner weld connection. The radially outer weld connection includes a radially outer weld bead that projects radially inwards into the cooling channel for forming a deflection element for the cooling medium received in the cooling channel.

A button-type secondary battery includes an electrode assembly in which electrodes and separators are alternately layered; a can case having an internal accommodation space in which the electrode assembly is accommodated; and an electrode tab having one side connected to each of the electrodes of the electrode assembly and the other side welded to the can case. A welding pattern appearing at a welding part, at which the electrode tab is welded to the can case, includes a circular shape and an additional shape in addition to the circular shape.

A secondary battery includes an electrode assembly, a current collector coupled to the electrode assembly, a case accommodating the electrode assembly and the current collector, a cap plate coupled to the case, the cap plate sealing the electrode assembly and the current collector in the case, and a terminal plate connected to the current collector, the terminal plate being exposed through the cap plate, wherein the current collector is welded to at least one of the electrode assembly and the terminal plate by both a dual beam welding and a wobble welding.

A transmission gear box is provided, which comprises a box body (10), at least one end cover (20, 20′) and a fitting structure. A cavity suitable for arranging gears is defined in the box body (10). The at least one end cover (20, 20′) is fixed on at least one opening end, which is axially opened, of the cavity of the box body (10). The fitting structure comprises an inner fitting surface (11) provided on the surface of the cavity of one of the box body (10) and the end cover (20, 20′), and an outer fitting surface (21) provided on the peripheral surface of the other one of the box body and the end cover, and the inner fitting surface (11) and the outer fitting surface (21) are fixed to each other by means of welding. At least one clearance fit area (30) and interference fit areas (40) located on both sides of the clearance fit area (30) are configured between the inner fitting surface (11) and the outer fitting surface (21). The provided transmission gear box can effectively avoid product deformation caused due to the fact that a molten body presses the box body (10) and the end cover (20, 20′) during welding.

A manufacturing method for a joint part in which a first metal piece and a second metal piece are joined to each other by performing welding by irradiating a high-energy beam to a joint surface on which the first metal piece and the second metal piece face each other, the first metal piece including a first flow path for passage of a fluid provided at a specific depth from a surface on a side exposed to the high-energy beam, the second metal piece including a second flow path for passage of the fluid provided at a specific depth from the surface on the side exposed to the high-energy beam, and the first flow path and the second flow path being coupled to each other on the joint surface.

A tool arrangement is provided for accommodating portions of an optical tool in a park position, having an optical tool and having a housing with an opening suitable for accommodating portions of the optical tool in a housing interior, with a housing discharge connected to the housing in a fluid-conducting manner, and with a sealing sleeve arranged at the opening of the housing, wherein the sealing sleeve has a fluid-carrying line for adapting a variable fill volume of the sealing sleeve. In addition, a method is provided for accommodating portions of an optical tool in a park position.