Abstract: A torque converter 1 is provided with a lockup device 4 having a simplified structure. Damper mechanism 40 has a drive member 54, a driven member 53 and a torsion spring 52. Piston 38 has an inner peripheral surface rotatably and axially movably supported on the outer peripheral surface of the driven member 53. The piston 38 is non-rotatably and axially movably coupled to the front cover 2. The piston 38 has an inner diameter S that is larger than an outer diameter of the damper mechanism 40. The piston 38 is arranged radially outside the damper mechanism 40. A seal ring 67 is disposed between the outer peripheral surface of the driven member 53 and the inner peripheral surface of the piston 38 for sealing spaces on its axially opposite sides from each other.

Abstract: The present invention relates to a method for making an oil passing hole in a plate where the plate is first provided with a pre-formed hole having a first diameter. A punch having a guiding part with a diameter smaller than the first diameter is inserted into the pre-formed hole. The punch also includes pressing part which is larger than the first diameter. The pressing part engages the plate as the guiding part extends into the pre-formed hole. Force applied by the pressing part causes portions of the plate to deform resulting in plastic flow of the portions of the plate. The plastic flow is in a radially inward direction causing portions of the plate to surround and engage the guiding part forming the oil passing hole which has a second diameter that is smaller than the first diameter.