The present invention provides a coupler comprising: an inner insertion part including a through-hole; and an outer support part for encompassing the outside of the inner insertion part, wherein the inner insertion part includes a connection groove through which the outer support part passes, the outer support part includes at least one projection part protruding in the center direction of the through-hole, and the projection part includes a groove part.

The present invention provides a coupler comprising: an inner insertion part including a through-hole; and an outer support part for encompassing the outside of the inner insertion part, wherein the inner insertion part includes a connection groove through which the outer support part passes, the outer support part includes at least one projection part protruding in the center direction of the through-hole, and the projection part includes a groove part.

Roll grooved pipe fittings useful in the assembly of a variety of mechanically joined piping systems. These pipe fittings are roll grooved so that they can be mechanically joined directly with other like pipe fittings and/or with roll grooved straight pipe thereby substantially simplifying assembly. In addition, hybrid pipe fittings and systems are also disclosed. Methods and apparatus for manufacturing these aforementioned roll grooved pipe fittings are also disclosed and address both the roll grooving process itself, as well as various methodology and apparatus for correcting deformations that can occur as a result of the roll grooving process. Methods for using the aforementioned apparatus are also disclosed.

Roll grooved pipe fittings useful in the assembly of a variety of mechanically joined piping systems. These pipe fittings are roll grooved so that they can be mechanically joined directly with other like pipe fittings and/or with roll grooved straight pipe thereby substantially simplifying assembly. In addition, hybrid pipe fittings and systems are also disclosed. Methods and apparatus for manufacturing these aforementioned roll grooved pipe fittings are also disclosed and address both the roll grooving process itself, as well as various methodology and apparatus for correcting deformations that can occur as a result of the roll grooving process. Methods for using the aforementioned apparatus are also disclosed.

The objective of the present invention is to improve the rigidity of a vehicle knuckle made from an aluminum alloy with respect to a force directed from the outside to the inside in the width direction of a vehicle. A vehicle knuckle (11) is provided with a bearing support portion (111), a knuckle upper portion (113) and a knuckle lower portion (112). With the vehicle knuckle (11) in a position fitted to a vehicle main body, the knuckle upper portion (113) has a shape in which, if the knuckle upper portion (113) is divided equally into five or more regions in a vertical direction, and the center of the bearing support portion (111) is fixed and a horizontal load F is applied to a knuckle upper end portion (115) from the outside toward the inside in the width direction of the vehicle, the minimum value of a value obtained by dividing the strain energy in each of the five or more regions other than a first region (11A) by the mass of the corresponding region is at least equal to 0.70 times the maximum value thereof.

The objective of the present invention is to improve the rigidity of a vehicle knuckle made from an aluminum alloy with respect to a force directed from the outside to the inside in the width direction of a vehicle. A vehicle knuckle (11) is provided with a bearing support portion (111), a knuckle upper portion (113) and a knuckle lower portion (112). With the vehicle knuckle (11) in a position fitted to a vehicle main body, the knuckle upper portion (113) has a shape in which, if the knuckle upper portion (113) is divided equally into five or more regions in a vertical direction, and the center of the bearing support portion (111) is fixed and a horizontal load F is applied to a knuckle upper end portion (115) from the outside toward the inside in the width direction of the vehicle, the minimum value of a value obtained by dividing the strain energy in each of the five or more regions other than a first region (11A) by the mass of the corresponding region is at least equal to 0.70 times the maximum value thereof.

A forging method for a shaft member includes preforming at least one of a plurality of enlarged diameter portions to obtain a semi-finished member, and forming a remainder of the enlarged diameter portions in the semi-finished member using a mold. The mold includes a punch, split dies, and a workpiece receiving member. The forming of the remainder of the enlarged diameter portions includes allowing the semi-finished member having the at least one of the enlarged diameter portions to be placed on the workpiece receiving member, cramping the semi-finished member in its radial direction by closing the split dies, and filling the semi-finished member into forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member is cramped.

A forging method for a shaft member includes preforming at least one of a plurality of enlarged diameter portions to obtain a semi-finished member, and forming a remainder of the enlarged diameter portions in the semi-finished member using a mold. The mold includes a punch, split dies, and a workpiece receiving member. The forming of the remainder of the enlarged diameter portions includes allowing the semi-finished member having the at least one of the enlarged diameter portions to be placed on the workpiece receiving member, cramping the semi-finished member in its radial direction by closing the split dies, and filling the semi-finished member into forming surfaces of the split dies by the pressure applied by the punch under the state in which the semi-finished member is cramped.

The objective of the present invention is to improve the rigidity of a vehicle knuckle made from an aluminum alloy with respect to a force directed from the outside to the inside in the width direction of a vehicle. A vehicle knuckle (11) is provided with a bearing support portion (111), a knuckle upper portion (113) and a knuckle lower portion (112). With the vehicle knuckle (11) in a position fitted to a vehicle main body, the knuckle upper portion (113) has a shape in which, if the knuckle upper portion (113) is divided equally into five or more regions in a vertical direction, and the center of the bearing support portion (111) is fixed and a horizontal load F is applied to a knuckle upper end portion (115) from the outside toward the inside in the width direction of the vehicle, the minimum value of a value obtained by dividing the strain energy in each of the five or more regions other than a first region (11A) by the mass of the corresponding region is at least equal to 0.70 times the maximum value thereof.

The objective of the present invention is to improve the rigidity of a vehicle knuckle made from an aluminum alloy with respect to a force directed from the outside to the inside in the width direction of a vehicle. A vehicle knuckle (11) is provided with a bearing support portion (111), a knuckle upper portion (113) and a knuckle lower portion (112). With the vehicle knuckle (11) in a position fitted to a vehicle main body, the knuckle upper portion (113) has a shape in which, if the knuckle upper portion (113) is divided equally into five or more regions in a vertical direction, and the center of the bearing support portion (111) is fixed and a horizontal load F is applied to a knuckle upper end portion (115) from the outside toward the inside in the width direction of the vehicle, the minimum value of a value obtained by dividing the strain energy in each of the five or more regions other than a first region (11A) by the mass of the corresponding region is at least equal to 0.70 times the maximum value thereof.