Valve open and close period control device

A valve open and close period control device comprising:

• a driving-side rotor that rotates synchronously with a crankshaft of an internal combustion engine about a rotational axis center;
• a driven-side rotor that is disposed coaxially with the rotational axis center on an inner side of the driving-side rotor, and rotates integrally with a camshaft for valve opening and closing of the internal combustion engine;
• and
• a phase adjustment mechanism that sets a relative rotation phase between the driving-side rotor and the driven-side rotor, wherein
• the phase adjustment mechanism includes:
• an output gear provided on the driven-side rotor coaxially with the rotational axis center;
• an input gear that is connected to the driving-side rotor and rotates about an eccentric axis center that is in an orientation parallel to the rotational axis center;
• and
• an eccentric member that has a tubular shape, supports the input gear from an inner peripheral side via a support bearing, and rotates the input gear,
• the eccentric member is configured to rotate to revolve the eccentric axis center to change a position of a meshing portion between the output gear and the input gear,
• the driven-side rotor has a support wall portion connected to an end portion of the camshaft, in an orientation orthogonal to the rotational axis center, and
• the support wall portion has an oil supply passage through which lubricating oil can be supplied from an outside of the driven-side rotor to an inside of the driven-side rotor,
• the driving-side rotor has a front plate on a side opposite to the camshaft with respect to the eccentric member, in a direction along the rotational axis center, and
• the valve open and close period control device has an oil reservoir structure that reduces a discharge amount of the lubricating oil discharged from an inside of the driving-side rotor, as compared to a supply amount of the lubricating oil supplied from the oil supply passage to the inside of the driven-side rotor when the driving-side rotor is rotating, wherein
• the phase adjustment mechanism further includes an Oldham's coupling having an annular portion and a pair of external engagement arms protruding radially outward from the annular portion along a direction in which the pair of external engagement arms are opposed to each other,
• the driving-side rotor is formed with a pair of guide grooves having a penetrating groove shape and extending radially outward along a direction in which the pair of guide grooves are opposed to each other from the inside of the driving-side rotor to an outside of the driving-side rotor, at an opening edge portion with which the front plate comes into contact,
• the pair of external engagement arms are individually engaged with the pair of guide grooves,
• each of the pair of guide grooves has a discharge flow path formed by notching from the inside of the driving-side rotor to the outside of the driving-side rotor, and
• the oil reservoir structure is configured to have a less oil amount of the lubricating oil discharged from the discharge flow path than an oil amount of the lubricating oil flowing through the oil supply passage when the driving-side rotor is rotating.