Abstract: The vehicle roof structure includes: a closely facing section that abuts or is adjacent to a side outer panel; a negative curved-surface section that is positioned more inwards in the vehicle width direction than the closely facing section of the roof panel, and has a recessed face that is indented downwards; and a mounting surface that is formed in the side outer panel at an inner side in the vehicle width direction to downwards of the vehicle towards, and at which the closely facing section abuts or is adjacent, in which an edge, on a side of the roof panel, of the brazing material that has solidified to join the roof panel and the side outer panel is positioned on the negative curved-surface section.

Abstract: The vehicle roof structure includes: a closely facing section that abuts or is adjacent to a side outer panel; a negative curved-surface section that is positioned more inwards in the vehicle width direction than the closely facing section of the roof panel, and has a recessed face that is indented downwards; and a mounting surface that is formed in the side outer panel at an inner side in the vehicle width direction to downwards of the vehicle towards, and at which the closely facing section abuts or is adjacent, in which an edge, on a side of the roof panel, of the brazing material that has solidified to join the roof panel and the side outer panel is positioned on the negative curved-surface section.

Abstract: While steel sheets are positioned and held by a holding mechanism, a first laser beam is applied to a heating region of the steel sheet to space the steel sheet from the other steel sheet by a predetermined distance. A second laser beam is applied to a welding region to weld the steel sheets. An amount of heat applied by the first laser beam, a moving speed of the first laser beam, and a focused spot diameter of the first laser beam are set to keep the sheet irradiated with the first laser beam in an unmelted state and plastically deform the sheet.

Abstract: While steel sheets are positioned and held by a holding mechanism, a first laser beam is applied to a heating region of the steel sheet to space the steel sheet from the other steel sheet by a predetermined distance. A second laser beam is applied to a welding region to weld the steel sheets. An amount of heat applied by the first laser beam, a moving speed of the first laser beam, and a focused spot diameter of the first laser beam are set to keep the sheet irradiated with the first laser beam in an unmelted state and plastically deform the sheet.

Abstract: A welding condition monitoring device for monitoring the welding state of a welding work portion by taking an image thereof by an image sensor having a wide dynamic range and capable of taking an image covering a very bright welding portion and relatively dark portion. The monitoring device selectively emphasizes the outputs of the image sensor for any of luminance areas of the image taken by the image sensor using a sensor output characteristic table and can provide an image clearly showing both the very bright welding portion and the dark bead portion with a sufficient contrast allowing an observer to reliably recognize the objects in the image.

Abstract: A welding condition monitoring device for monitoring the welding state of a welding work portion by taking an image thereof by an image sensor having a wide dynamic range and capable of taking an image covering a very bright welding portion and relatively dark portion. The monitoring device selectively emphasizes the outputs of the image sensor for any of luminance areas of the image taken by the image sensor using a sensor output characteristic table and can provide an image clearly showing both the very bright welding portion and the dark bead portion with a sufficient contrast allowing an observer to reliably recognize the objects in the image.

Abstract: An apparatus for adjusting an optical component has a reference beam unit for emitting a reference laser beam L whose optical axis has established, and an optical axis unit detecting the optical axis and focal point of a reflected beam La from a parabolic mirror to which the reference laser beam L is applied. The optical axis unit comprises first and second pinhole plates spaced a given distance from each other and having respective small holes defined therein.

Abstract: A welding condition monitoring device for monitoring the welding state of a welding work portion by taking an image thereof by an image sensor having a wide dynamic range and capable of taking an image covering a very bright welding portion and relatively dark portion. The monitoring device selectively emphasizes the outputs of the image sensor for any of luminance areas of the image taken by the image sensor using a sensor output characteristic table and can provide an image clearly showing both the very bright welding portion and the dark bead portion with a sufficient contrast allowing an observer to reliably recognize the objects in the image.

Abstract: An apparatus for adjusting an optical component has a reference beam unit (10) for emitting a reference laser beam L whose optical axis has established, and an optical axis unit (70) detecting the optical axis and focal point of a reflected beam La from a parabolic mirror (222) to which the reference laser beam L is applied. The optical axis unit (70) comprises first and second pinhole plates (74, 76) spaced a given distance from each other and having respective small holes (80, 90) defined therein.