| 主权项 |
1. A valve timing control apparatus for an internal combustion engine, comprising:
a generally cylindrical housing body rotatable by a rotational force that is transmitted from a crankshaft of the engine to the housing body, the housing body being opened to at least one axial end thereof, the housing body having a plurality of shoes projecting on an inner periphery thereof to define a plurality of hydraulic chambers; a vane rotor comprising a rotor body fixed to a camshaft, and a plurality of vanes projecting on an outer periphery thereof to divide the plurality of hydraulic chambers into phase-advance hydraulic chambers and phase-retard hydraulic chambers, the vane rotor being rotatable relative to the housing body toward a phase-advance side by supplying hydraulic pressure to the phase-advance hydraulic chambers and discharging hydraulic pressure from the phase-retard hydraulic chambers, the vane rotor being rotatable relative to the housing body toward a phase-retard side by supplying hydraulic pressure to the phase-retard hydraulic chambers and discharging hydraulic pressure from the phase-advance hydraulic chambers; a front plate fixed to an axial end of the housing body, the front plate comprising a cylindrical sleeve portion that projects from a central portion of the front plate, and a cutout portion formed on a side of an axial end of the sleeve portion, the cutout portion extending through a circumferential wall of the sleeve portion in parallel to a radial direction of the sleeve portion over a predetermined angular range in a circumferential direction of the sleeve portion; and a torsion spring having one end portion fixed to the vane rotor and another end portion bent in a radially outward direction of the torsion spring and fixedly engaged with the cutout portion, wherein the cutout portion comprises one side wall surface, another side wall surface opposed to the one side wall surface in a substantially parallel relation thereto, and an end wall surface with which the another end portion of the torsion spring is engaged, the cutout portion being formed such that a first straight line extending through the end wall surface toward an inner peripheral side of the sleeve portion is located closer to the central axis of the sleeve portion than a second straight line extending through the another side wall surface toward the inner peripheral side of the sleeve portion, wherein the cutout portion comprises a stop to restrict displacement of the another end portion of the torsion spring in an axial direction of the torsion spring, wherein the cutout portion has a first circumferential width on the side of the axial end of the sleeve portion and a second circumferential width on a side of an opposite axial end of the sleeve portion which is larger than the first circumferential width, the stop extending by a difference between the first circumferential width and the second circumferential width. |
