Phase controlling system for two rotatable shafts

A valve timing device for an internal combustion engine comprising;

• a driving member including a hub having a central bore therethrough and a peripheral section keyed thereto for torque transfer therebetween while allowing axial movement of said hub relative to said peripheral section;
• said hub coaxially mounted to one of the camshaft or crankshaft of said engine for movement relative thereto;
• said hub and outer peripheral section of said driving member drivenly engaged to said crankshaft and drivingly engaged to said camshaft;
• a helical tracking means interposed between said hub and said one shaft for angularly changing the relative positions of said driving member with respect to said one shaft as the hub axially moves relative to said one shaft with said camshaft, having a retarding torque load exerted thereon, operably applying a torque load on said hub;
• a coil compression spring coaxially mounted about said one shaft and in biasing relationship between said hub and shaft for biasing the hub axially along said one shaft for preventing movement of said hub relative to said one shaft when a torque load on said camshaft is below a predetermined minimum as said crankshaft and camshaft rotate and to resiliently resist movement of said hub relative to said one shaft when said torque load exceeds said predetermined minimum such that the axial and angular movement of said hub relative to said one shaft and thereby the angular retardation of said camshaft relative to said crankshaft is proportional to said torque load on said cam shaft.

A phase controlling system between a rotatable driving shaft and a driven member, said system comprising;

• a hub coaxially mounted about said driving shaft for rotational and axial movement relative thereto;
• said hub drivingly engaged to said driven member and drivingly engaged to said driving shaft;
• spring means for controlling the axial movement of said hub along said driving shaft and counterbalancing an axial directed force from said inertial and frictional loads of said driven member to allow predetermined angular and axial changes of said hub about said driving shaft for changes in the load of said driven member such that for rotational speeds of said driving shaft, said driven member is predeterminedly phase retarded with respect to said driving shaft as compared to said relative phase of said driving shaft and driven member at rest;
• said spring means having sufficient strength not to respond to normal angular accelerations and decelerations of said driven member.