Abstract: A friction engagement device of an automatic transmission is provided, which includes a rotational member comprised of at least one of a drum member and a hub member including a spline part engaged with a friction plate to be movable in axial directions of the automatic transmission, and a drive force transmitting part for exchanging a drive force with another rotational element. The drive force transmitting part of the rotational member is made of a ferrous metal. A part of the rotational member other than the drive force transmitting part is made of a clad material containing a first material that is easily joined to the ferrous metal and a second material that is less easily joined to the ferrous metal compared to the first material and weighs less than the ferrous metal.

Abstract: A friction engagement device of an automatic transmission is provided, which includes a rotational member comprised of at least one of a drum member and a hub member including a spline part engaged with a friction plate to be movable in axial directions of the automatic transmission, and a drive force transmitting part for exchanging a drive force with another rotational element. The drive force transmitting part of the rotational member is made of a ferrous metal. A part of the rotational member other than the drive force transmitting part is made of a clad material containing a first material that is easily joined to the ferrous metal and a second material that is less easily joined to the ferrous metal compared to the first material and weighs less than the ferrous metal.

Abstract: In a clutch manufacturing method, inner peripheral portions of drum members, of two clutches are connected to a sleeve member, and a piston, a seal plate and a return spring are provided between the drum members, an insulator to apply electric isolation between the piston and the drum member or between the seal plate and another drum member is attached to either the piston or the seal plate. Then, the drum member, to which the electric isolation with the insulator is not applied, is connected to the sleeve member. Then, the piston, return sprig and seal plate are assembled to the sleeve member to which the drum member has been connected. Finally, the drum member, to which the electric isolation with the insulator has been applied, is connected to the sleeve member with electric welding.

Abstract: In a clutch manufacturing method, inner peripheral portions of drum members, of two clutches are connected to a sleeve member, and a piston, a seal plate and a return spring are provided between the drum members, an insulator to apply electric isolation between the piston and the drum member or between the seal plate and another drum member is attached to either the piston or the seal plate. Then, the drum member, to which the electric isolation with the insulator is not applied, is connected to the sleeve member. Then, the piston, return sprig and seal plate are assembled to the sleeve member to which the drum member has been connected. Finally, the drum member, to which the electric isolation with the insulator has been applied, is connected to the sleeve member with electric welding.