Valve timing control device

A hydraulic-type valve timing control device for an internal combustion engine for controlling an opening and/or closing timing of a valve, in which engine torque is transmitted from a crank shaft of the engine to a cam shaft in order to open and/or close the valve, comprising:

• a housing rotor to be rotated in a circumferential direction in synchronism with the crank shaft, the housing rotor having multiple shoes each of which extends in a radial-inward direction from a housing body of a cylindrical shape, the housing rotor defining multiple vane accommodating chambers in the circumferential direction between neighboring shoes;
• a vane rotor to be rotated in the circumferential direction in synchronism with the cam shaft, the vane rotor being rotatably accommodated in the housing rotor so that a rotational phase of the vane rotor with respect to the housing rotor is adjusted, the vane rotor having multiple vanes each of which extends in a radial-outward direction from a rotating shaft and is accommodated in each of the vane accommodating chambers so that an advancing chamber and a retarding chamber are formed in the circumferential direction in each of the vane accommodating chamber, the rotational phase of the vane rotor being advanced when working fluid is introduced into the advancing chamber and working fluid is discharged from the retarding chamber, and the rotational phase of the vane rotor being retarded when the working fluid is introduced into the retarding chamber and the working fluid is discharged from the advancing chamber;
• and
• a sealing member supported by a holding surface and sliding on a sealing surface for sealing the advancing chamber and the retarding chamber from each other, the holding surface being formed by one of an inner peripheral surface of the housing rotor and an outer peripheral surface of the vane rotor, and the sealing surface being formed by the other of the inner peripheral surface of the housing rotor and the outer peripheral surface of the vane rotor,
• wherein the sealing member is composed of;
• a pressure-receiving surface for receiving pressure of the working fluid from a working chamber, which is either one of the advancing chamber and the retarding chamber, the pressure of the working fluid being directed toward the sealing surface;
• a diffuser surface for forming a sealing gap between the diffuser surface and the sealing surface in a radial direction of the vane rotor, the sealing gap being increased as the sealing gap is more separated from the working chamber in the circumferential direction, the diffuser surface diffusing the working fluid flowing through the sealing gap;
• and
• a deformable portion having the pressure-receiving surface and the diffuser surface, the deformable portion keeping the diffuser surface at an initial position when the pressure of the working fluid is not applied to the pressure-receiving surface so that the diffuser surface is separated from the sealing surface, the diffuser surface being more strongly pushed to the sealing surface as the pressure of the working fluid applied to the pressure-receiving surface is increased.