Abstract: A hydraulic transmission apparatus with a lockup clutch has a pump impeller, a turbine runner, a side cover, a lockup clutch, a clutch piston, a lockup control unit, a frictional engagement unit and a resilient member, a backward movement stopping unit, wherein a transmission capacity of the lockup clutch by virtue of a biasing force of the resilient member is set smaller than a torque absorption capacity of the pump impeller when the engine is in an idle state so that the clutch piston is held at the predetermined backward position by virtue of the pressure difference when the engine is in the idle state.

Abstract: A fluid transmitting system includes a lock-up clutch whose clutch piston is disposed between a side cover connected to a pump impeller and a turbine runner. A Belleville spring for biasing the clutch piston to a clutch turning-on direction is mounted to a piston hub of the clutch piston slidably carried on a turbine hub so that the deformation attitude thereof is changed freely. A limiting means is provided between the clutch piston and the turbine runner for limiting the amount of retraction of the clutch piston to a constant value thereby preventing excessive deformation of the Belleville spring, when the clutch piston is retracted in a clutch turning-off direction. Thus, the Belleville spring for biasing the clutch piston of the lock-up clutch in the clutch turning-on direction can exhibit an intrinsic spring characteristic, and moreover the durability of the Belleville spring can be enhanced.

Abstract: A fluid transmitting system includes a lock-up clutch whose clutch piston is disposed between a side cover connected to a pump impeller and a turbine runner. A Belleville spring for biasing the clutch piston to a clutch turning-on direction is mounted to a piston hub of the clutch piston slidably carried on a turbine hub so that the deformation attitude thereof is changed freely. A limiting means is provided between the clutch piston and the turbine runner for limiting the amount of retraction of the clutch piston to a constant value thereby preventing excessive deformation of the Belleville spring, when the clutch piston is retracted in a clutch turning-off direction. Thus, the Belleville spring for biasing the clutch piston of the lock-up clutch in the clutch turning-on direction can exhibit an intrinsic spring characteristic, and moreover the durability of the Belleville spring can be enhanced.

Abstract: A hydraulic transmission apparatus with a lockup clutch has a pump impeller, a turbine runner, a side cover, a lockup clutch, a clutch piston, a lockup control unit, a frictional engagement unit and a resilient member, a backward movement stopping unit, wherein a transmission capacity of the lockup clutch by virtue of a biasing force of the resilient member is set smaller than a torque absorption capacity of the pump impeller when the engine is in an idle state so that the clutch piston is held at the predetermined backward position by virtue of the pressure difference when the engine is in the idle state.

Abstract: A torque converter in which a flatness (2L/H) and a torus inside and outside radius ratio (r/R) satisfy the following equations: (1) 0.55<(2L/H)<0.75 and (2) 35<(r/R)<0.40. Then, assuming that an axially central position of the flow path along a rotational shaft of the torque converter is an origin, an axial direction is an X direction and a radial direction is a Y direction, the configuration of the flow path of the turbine member is set such that the position of a point of contact between a straight line inclined 45 degrees relative to the X direction and a curve constituting an external circumference surface of the flow path in the turbine member is located within an area surrounded by two straight lines expressed as (3) Y=(R/L)×X+(6/4)×R and (4) Y=(R/L)×X+(7/4)×R.

Abstract: A torque converter TC is constituted having an impeller 11, a turbine 12, a stator 13, a converter cover 11a, which covers the back side of the turbine, and is connected to the impeller, and a lock-up mechanism, which couples and uncouples the impeller and turbine. The lock-up mechanism comprises a lock-up piston 15, which is arranged by being linked to the turbine inside a space enclosed by the converter cover 11a, and lock-up is performed by the lock-up piston mating under pressure to the inner surface of the converter cover due to oil pressure inside a lock-up fastening chamber 17, which is enclosed by the lock-up piston and the back side of the turbine in a space enclosed by the converter cover.