Abstract: A deburring tool for cutting burr generated when members are welded to each other by friction stir welding is provided. The deburring tool includes a tool center portion contacting a welding portion, and a blade portion formed on an outer circumference of the tool center portion to cut the burr. The tool center portion includes a protrusion protruding downward from a ridge line of the blade portion to control a burr cutting amount.

Abstract: A decompression path conductance factor calculation device 110 obtains a cavity pressure change characteristic representing a pressure change characteristic of a cavity portion 30 from an exhaust speed of a decompression device 70, a cavity conductance factor, an overflow conductance factor, a decompression path conductance factor, and respective volumes of inside spaces of a cavity portion 30, an overflow portion 50, and a decompression path 60, obtains a decompression path pressure change characteristic representing a pressure change characteristic of the decompression path 60 from the exhaust speed of the decompression device 70, the volume of the inside space of the decompression path 60, and the decompression path conductance factor, and obtains the decompression path conductance factor such that a difference between respective approximate curves representing the obtained cavity pressure change characteristic and the obtained decompression path pressure change characteristic becomes a threshold value or

Abstract: The present invention makes it possible to weld workpieces to each other efficiently firmly by friction stir welding while reducing labor and man-hours. A friction stir welding method includes a fixing step, a temporary welding step S2, and a main welding step as follows. The fixing step includes fixing the workpieces W1 and W2 to a receiving table by pressing the workpieces W1 and W2 against the receiving table by means of a plurality of spring pins 10 that, are spaced apart from one another. The temporary welding step S2 includes spot-welding the workpieces W1 and W2 to each other by friction stir welding at locations different from positions of the spring pine 10. The main welding step includes line-welding the spot-welded workpieces W1 and W2 to each other by friction stir welding.

Abstract: A decompression path conductance factor calculation device 110 obtains a cavity pressure change characteristic representing a pressure change characteristic of a cavity portion 30 from an exhaust speed of a decompression device 70, a cavity conductance factor, an overflow conductance factor, a decompression path conductance factor, and respective volumes of inside spaces of a cavity portion 30, an overflow portion 50, and a decompression path 60, obtains a decompression path pressure change characteristic representing a pressure change characteristic of the decompression path 60 from the exhaust speed of the decompression device 70, the volume of the inside space of the decompression path 60, and the decompression path conductance factor, and obtains the decompression path conductance factor such that a difference between respective approximate curves representing the obtained cavity pressure change characteristic and the obtained decompression path pressure change characteristic becomes a threshold value or

Abstract: A fine metal particle producing mechanism has a metal holder for housing a body of magnesium, a tube for supplying an argon gas to the body of magnesium, an argon gas flow rate controller for controlling a rate at which the argon gas is supplied to the tube, and an argon gas heating controller for heating the argon gas supplied to the tube to a predetermined temperature.

Abstract: A cylinder sleeve for being inserted in a cylinder bore defined in a block body of a cylinder block for an internal combustion engine. The cylinder bore includes a first annular recess and a second annular recess, and projecting walls. The cylinder sleeve comprises a hollow cylindrical body that is inserted into the cylinder block with at least part of an outer circumferential wall thereof adjacent to an inner circumferential wall of the projecting walls of the cylinder block, a larger-diameter portion projecting diametrally outwardly from an upper end of the outer circumferential wall of the hollow cylindrical body, a step disposed on an outer circumferential wall of said larger-diameter portion, by which the larger-diameter portions of adjacent cylinder sleeves are stacked, and a reduced-diameter portion provided by reducing a diameter of an inner circumferential wall of said hollow cylindrical body.

Abstract: A fine metal particle producing mechanism has a metal holder for housing a body of magnesium, a tube for supplying an argon gas to the body of magnesium, an argon gas flow rate controller for controlling a rate at which the argon gas is supplied to the tube, and an argon gas heating controller for heating the argon gas supplied to the tube to a predetermined temperature.

Abstract: A fine metal particle producing mechanism has a metal holder for housing a body of magnesium, a tube for supplying an argon gas to the body of magnesium, an argon gas flow rate controller for controlling a rate at which the argon gas is supplied to the tube, and an argon gas heating controller for heating the argon gas supplied to the tube to a predetermined temperature.

Abstract: A reduced-diameter portion (44) with a taper portion (46), a portion whose diameter is reduced in a tapered form, is provided on an inner peripheral wall of a cylinder sleeve (20a, 20b, 20c). On the outer peripheral wall of the top end of the cylinder sleeve (20a, 20b, 20c) is provided a large diameter portion (36a, 36b, 36c) projected outward along the diameter direction. Under the action of a friction stir welding tool (50), the cylinder sleeve (20a, 20b, 20c) inserted in a communication hole (16) of a block body (18) is joined to the block body (18) with the reduced-diameter portion (44) and the large-diameter portion (36a, 36b, 36c) in between. A closed deck-type cylinder block (10) is constructed with the process above. In the cylinder block (10), the gasket face (12) side of a water jacket (22) is closed by the large-diameter portion (36a, 36b, 36c).

Abstract: A fine metal particle producing mechanism has a metal holder for housing a body of magnesium, a tube for supplying an argon gas to the body of magnesium, an argon gas flow rate controller for controlling a rate at which the argon gas is supplied to the tube, and an argon gas heating controller for heating the argon gas supplied to the tube to a predetermined temperature.