Torque converter

A torque converter comprising:

• a casing coupled to an output shaft of an engine;
• a pump disposed within the casing and adapted to be rotated integrally with the casing;
• a turbine disposed opposed to the pump from a side of the engine with respect to the pump;
• a stator disposed between the pump and the turbine;
• a multi-plate lockup clutch adapted to directly couple the turbine and the casing;
• and
• a lockup damper adapted to absorb shock during engagement of the lockup clutch,
• wherein the pump, the turbine and the stator define a torus which serves as a fluid working section for causing fluid within the casing to circulate therearound, and
• a part of the outer peripheral portion of a turbine shell being convexly curved toward the engine and being a widest region of the turbine shell,
• wherein the lockup clutch and the lockup damper being arranged laterally within a space between the torus and a surface of the casing on the side of the engine in such a manner that a part of the lockup clutch and the part of the outer peripheral portion of the turbine shell corresponding to the widest region being disposed to overlap with each other in an imaginary plane oriented perpendicular to a rotational axis of the lockup clutch,
• the lockup clutch being disposed entirely on a radially inner side with respect to the widest region of the turbine shell where an axial dimension of the turbine shell becomes largest, and the lockup damper being disposed entirely on a radially outer side with respect to the widest region of the turbine shell,
• the casing has a bulged portion in a radially intermediate part of a wall section closer to the engine, the bulged portion bulging toward the engine more than a radially inner part of the wall section, and
• the lockup clutch has a piston which is driven in an axial direction by an oil pressure, the piston being disposed only within a radial range of the bulged portion,
• the torque converter further comprising:
• a fixed plate member attached onto an inner surface of the wall section of the casing on a radially inner side of the lockup clutch;
• and
• an oil passage formed between the wall section of the casing and the plate member so as to supply therethrough a working pressure to the piston,
• the fixed plate member having an outer peripheral end extending to a position within the bulged portion, and
• an end of the piston located furthest away from the engine being disposed closer to the engine than an end of the fixed plate member located furthest away from the engine.

A torque converter comprising:

• a casing coupled to an output shaft of an engine;
• a pump disposed within the casing and adapted to be rotated integrally with the casing;
• a turbine disposed opposed to the pump from a side of the engine with respect to the pump;
• a stator disposed between the pump and the turbine;
• a multi-plate lockup clutch adapted to directly couple the turbine and the casing;
• and
• a lockup damper adapted to absorb shock during engagement of the lockup clutch,
• wherein the pump, the turbine and the stator define a torus which serves as a fluid working section for causing fluid within the casing to circulate therearound, and
• a part of the outer peripheral portion of a turbine shell being convexly curved toward the engine and being a widest region of the turbine shell,
• wherein the lockup clutch and the lockup damper being arranged laterally within a space between the torus and a surface of the casing on the side of the engine in such a manner that a part of the lockup clutch and the part of the outer peripheral portion of the turbine shell corresponding to the widest region being disposed to overlap with each other in an imaginary plane oriented perpendicular to a rotational axis of the lockup clutch,
• the lockup clutch being disposed entirely on a radially inner side with respect to a widest region of the turbine shell where an axial dimension of the turbine shell becomes largest, and the lockup damper being disposed entirely on a radially outer side with respect to the widest region of the turbine shell,
• a ratio D1/D2 is set in a range of 1.5 to 1.6, where D1 is an outer diameter of the torus, and D2 is an inner diameter of the torus, and
• the lockup clutch is engaged when a speed ratio is not less than 0.3 and less than 1, where the speed ratio is a ratio of a rotation speed of the turbine to a rotation speed of the pump.