Abstract: A flange of a left rear side portion (aluminum member) includes a plane section extending toward a vertical wall of a left side member (steel plate-like member). The left side member includes a bent portion formed as a result of being bent between a flange and the vertical wall of the left side member, and a base section, which serves as a start point at which the bent section starts to be bent from the flange of the left side member. The plane section of the left rear side portion is provided such that it covers an area substantially up to the base section of the left side member.

Abstract: Disclosed is a friction stir welding tool (10) equipped with a probe (13) and a holder (16). At the tip of the probe (13) there is a pin part (11) and at the base there are probe-side protrusions (24) and probe-side recesses (25). At the tip of the holder (16) there are holder-side recesses (27) which mate with the probe-side protrusions (24), and holder-side protrusions (28) which mate with the probe-side recesses (25). External force applied to the probe (13) is transmitted from the probe-side protrusions (24) to the holder-side recesses (27) and from the probe-side recesses (25) to the holder-side protrusions (28).

Abstract: Disclosed is a friction-stir joining method for joining a first member, having a base metal covered with a substance different from the base metal, with a second member with the second member placed on the first member by moving a joining tool along a joining line having thereon a joining start point and a joining finish point. The method includes steps of: inserting the joining tool into the second member at the joining start point; moving the joining tool a predetermined distance along the joining line in a direction opposite the joining finish point; causing the joining tool to turn back at a turning-back point spaced the predetermined distance from the joining start point; moving the joining tool along the joining line to the joining finish point past the joining start point; and pulling the joining tool out from the second member at the joining finish point.

Abstract: Friction stir welding is performed in the following manner. In the state in which a probe is rotated in a predetermined rotation direction, the probe is inserted into a flange of a rear sub frame, thereby starting friction stir welding to weld the flange of the rear sub frame and a flange of a front sub frame positioned on the inner side of the rear side of a vehicle. The probe is sequentially moved along the direction of arrow R1?arrow R2 (predetermined direction). When the probe reaches the end point of the direction indicated by arrow R2, the probe is inserted into the flange on the outer side across a protruding portion disposed between the flanges. Then, the probe is sequentially moved in the direction of arrow R4?arrow R5?arrow R6, which is opposite to the direction of arrow R1?arrow R2.

Abstract: Extending portions of a front sub-frame are each formed by stacking two thin plates made of steel, and flange portions of the front sub-frame and flange portions of a rear sub-frame made of aluminum are superimposed on each other, and are friction stir welded, with a seal material applied to the superimposed surfaces. Of the two thin plates, the thin plate joined to the rear sub-frame made of aluminum has, at each end thereof, a bent portion and an extending part. The bent portion is formed by bending. The end of the extending part extends outward farther than the rear sub-frame. The extending part is covered by the seal material. The bent portion is disposed at a farther end of the extending part.

Abstract: A flange of a left rear side portion (aluminum member) includes a plane section extending toward a vertical wall of a left side member (steel plate-like member). The left side member includes a bent portion formed as a result of being bent between a flange and the vertical wall of the left side member, and a base section, which serves as a start point at which the bent section starts to be bent from the flange of the left side member. The plane section of the left rear side portion is provided such that it covers an area substantially up to the base section of the left side member.

Abstract: Disclosed is a friction stir welding tool (10) equipped with a probe (13) and a holder (16). At the tip of the probe (13) there is a pin part (11) and at the base there are probe-side protrusions (24) and probe-side recesses (25). At the tip of the holder (16) there are holder-side recesses (27) which mate with the probe-side protrusions (24), and holder-side protrusions (28) which mate with the probe-side recesses (25). External force applied to the probe (13) is transmitted from the probe-side protrusions (24) to the holder-side recesses (27) and from the probe-side recesses (25) to the holder-side protrusions (28).

Abstract: Disclosed is a friction-stir joining method for joining a first member, having a base metal covered with a substance different from the base metal, with a second member with the second member placed on the first member by moving a joining tool along a joining line having thereon a joining start point and a joining finish point. The method includes steps of inserting the joining tool into the second member at the joining start point; moving the joining tool a predetermined distance along the joining line in a direction opposite the joining finish point; causing the joining tool to turn back at a turning-back point spaced the predetermined distance from the joining start point; moving the joining tool along the joining line to the joining finish point past the joining start point; and pulling the joining tool out from the second member at the joining finish point.

Abstract: The present invention comprises: a front subframe consisting of steel and divided in the front-rear direction of the vehicle; and a rear subframe consisting of light metal such as an aluminum alloy. The front subframe comprises a press-formed body formed by pressing. The rear subframe comprises a die-cast body formed by die-casting. The front subframe and the rear subframe are joined together by friction stir welding while the left and right rear side sections of the rear subframe are superposed on the upper surfaces of the thin plate sections of the front subframe.

Abstract: In a structure for mounting a subframe, located under a vehicle body, to the vehicle body via an elastic assembly, the elastic assembly includes: a first mounting member located under the vehicle body and over the subframe; a second mounting member located immediately above the first mounting member; and an elastic member disposed between the first and second mounting members. The first mounting member is mounted to the vehicle body, while the second mounting member is mounted to the subframe.

Abstract: A friction stir welding member is formed by welding a second member to a first member in such a manner that a second member is stacked on a first member, a material property of the second member being different from a material property of the first member, a pin of a welding tool using a Friction Stir Welding technique is inserted into the second member, welding is started at one end of the second member, and the pin is pulled out at a welding terminal portion before the pin reaches the other end of the second member. A projection projecting toward the welding tool is provided integrally with the second member, the projection is formed so as to have a height that is higher than a length of the pin, and the projection is provided with the welding terminal portion.

Abstract: In a structure for mounting a subframe, located under a vehicle body, to the vehicle body via an elastic assembly, the elastic assembly includes: a first mounting member located under the vehicle body and over the subframe; a second mounting member located immediately above the first mounting member; and an elastic member disposed between the first and second mounting members. The first mounting member is mounted to the vehicle body, while the second mounting member is mounted to the subframe.