Patent ID: 7650973

Claim:
A hydraulic power transmission device, comprising: a front cover engaged with a drive power source; a rear cover engaged with the front cover; a pump impeller attached to the rear cover; a toroid portion that includes a turbine runner that is installed such that fluid transmits a drive power from the pump impeller; a turbine hub engaged with an input shaft of a transmission and holds the turbine runner; and a lock-up device that is connected to the turbine hub, wherein: when the lock-up device is released, a power transmission route is formed by the front cover, the pump impeller, the turbine runner, the turbine hub, and the input shaft, when the lock-up device is engaged, a power transmission route is formed by the front cover, the lock-up device, the turbine hub, and the input shaft, the lock-up device includes a clutch drum, the clutch drum is engaged with the turbine hub, and overlaps with the toroid portion in an axial direction, and an engaging side oil chamber is formed to the inside of an engaging and disengaging member of the lock-up device in a radial direction.