Abstract: Respective outer peripheral surfaces (33, 35) of opening-side end portions (30, 31) of a front cover (12) and a pump shell (7), which have been shaped by pressing, are formed by slimming such that the outside diameters of the slimmed outer peripheral surfaces are equal to each other. With the opening-side end portions abutting against each other, a high-energy beam such as a laser beam (R) is radiated toward the abutment surfaces (30, 31) from the radially outer side to weld the abutment surfaces to each other. Consequently, it is possible to perform welding accurately through easy processing in order to easily manufacture a fluid coupling with high precision that facilitates post-processing.

Abstract: Respective outer peripheral surfaces (33, 35) of opening-side end portions (30, 31) of a front cover (12) and a pump shell (7), which have been shaped by pressing, are formed by slimming such that the outside diameters of the slimmed outer peripheral surfaces are equal to each other. With the opening-side end portions abutting against each other, a high-energy beam such as a laser beam (R) is radiated toward the abutment surfaces (30, 31) from the radially outer side to weld the abutment surfaces to each other. Consequently, it is possible to perform welding accurately through easy processing in order to easily manufacture a fluid coupling with high precision that facilitates post-processing.

Abstract: A drive plate includes a plate section coupled to a crankshaft of an engine and a rim section including a plurality of teeth that meshes with a pinon gear of a cell motor for cranking the engine. The plate section and the rim section are integrally molded by press working the drive plate in an axial direction. A free end on a side opposite to a base end which is connected to the plate section of the rim section is brought closer than the base end to a central axis of the plate section, that is, the drive plate.

Abstract: A lockup clutch mechanism of a hydraulic transmission device includes a lockup piston that is capable of moving toward a front cover to press first and second friction plates, and a flange member that together with the lockup piston defines an engagement-side oil chamber. The front cover and the lockup piston define a first lubricant passage that supplies hydraulic oil to the first and second friction plates. A second lubricant passage communicating with the first lubricant passage is formed in a centerpiece of the front cover. A first shaft oil passage communicating with the engagement-side oil chamber and a second shaft oil passage communicating with the second lubricant passage are formed in an input shaft.

Abstract: In a hydraulic transmission apparatus, a lockup piston of a lockup clutch mechanism is placed on the opposite side of first and second friction plates from a sidewall portion of a front cover. A damper device is placed on the opposite side of the lockup piston from the first and second friction plates. An outer peripheral portion of the lockup piston is located closer to the outer periphery than an outer peripheral portion of a flange member. A part of the lockup piston is placed in a region located between first and second springs and a third spring of the damper device in a radial direction and in the range of an axial width of the third spring located closer to the lockup piston.

Abstract: A damper device including an input element to which power from a motor is transmitted; a first elastic body to which power is transmitted from the input element; a first intermediate element to which power is transmitted from the first elastic body; a second elastic body to which power is transmitted from the first intermediate element; a second intermediate element to which power is transmitted from the second elastic body; a third elastic body to which power is transmitted from the second intermediate element; and an output element to which power is transmitted from the third elastic body. A stiffness of the first elastic body is higher than a stiffness of the second elastic body.

Abstract: A lockup clutch mechanism of a hydraulic transmission device includes a lockup piston that is capable of moving toward a front cover to press first and second friction plates, and a flange member that together with the lockup piston defines an engagement-side oil chamber. The front cover and the lockup piston define a first lubricant passage that supplies hydraulic oil to the first and second friction plates. A second lubricant passage communicating with the first lubricant passage is formed in a centerpiece of the front cover. A first shaft oil passage communicating with the engagement-side oil chamber and a second shaft oil passage communicating with the second lubricant passage are formed in an input shaft.

Abstract: In a hydraulic transmission apparatus, a lockup piston of a lockup clutch mechanism is placed on the opposite side of first and second friction plates from a sidewall portion of a front cover. A damper device is placed on the opposite side of the lockup piston from the first and second friction plates. An outer peripheral portion of the lockup piston is located closer to the outer periphery than an outer peripheral portion of a flange member. A part of the lockup piston is placed in a region located between first and second springs and a third spring of the damper device in a radial direction and in the range of an axial width of the third spring located closer to the lockup piston.

Abstract: A damper device including an input element to which power from a motor is transmitted; a first elastic body to which power is transmitted from the input element; a first intermediate element to which power is transmitted from the first elastic body; a second elastic body to which power is transmitted from the first intermediate element; a second intermediate element to which power is transmitted from the second elastic body; a third elastic body to which power is transmitted from the second intermediate element; and an output element to which power is transmitted from the third elastic body. A stiffness of the first elastic body is higher than a stiffness of the second elastic body.

Abstract: The disclosed method produces a spline-grooved cylindrical member, e.g. torque converter front cover, including a cylindrical portion having a target wall thickness t2, from a plate blank having a plate thickness t1. An outer peripheral portion of a disc-shaped blank is plastically deformed by pressing it against a mandrel with the concave peripheral edge of a thickness-increasing roller, so that a thick wall portion, of a thickness greater than the plate thickness t1 of the blank, is formed in the cylindrical portion. The thick wall portion is then pressed against the mandrel by forming rollers to form spline grooves therein. Thus, the other portions of the product have a wall thickness which is not unnecessarily increased. In this manner, the wall thickness t2 of the cylindrical portion is not entirely dictated by the wall thickness t1 of the blank material.

Abstract: A surface hardening method, in which a surface layer on a thin steel plate member is stably melted and solidified to provide a high surface resistance against wear includes irradiation with a high density energy beam to melt a process surface portion of the steel member followed by rapid cooling. The melted surface portion includes a fully melted layer and an adjacent imperfectly or partially melted layer. At least the cooling to solidify the molten steel is performed in a short time period less than an austenitic transformation completion time at temperatures below melting, e.g., one-twentieth of the normal austenitic transformation time, and preferably both heating to melt the surface layer and cooling to solidify and harden the surface layer are performed in a time period less than the normal austenitic transformation completion time period. The high density energy beam can be divided to irradiate plural regions to melt the surfaces of the plural regions at the same time.

Abstract: A lockup clutch for torque converter which prevents engaging and disengaging shock when a transmission torque suddenly changes, includes a lockup clutch assembly, a lockup clutch piston operating the lockup clutch assembly, and a damper device disposed between the lockup clutch piston and an output member for absorbing changes of transmission torque occurring in association with the operation of the lockup clutch assembly. The lockup clutch piston is made of steel and has a thermally treated portion placed at a surface in contact with springs of the damper device wherein the thermally treated portion is hardened by rapid local melting with high density energy radiation such as electron beam followed by rapid cooling.