Torsion damping mechanism for a supercharger

A rotary blower of the backflow-type comprising a housing;

• first and second meshed lobed rotors rotatably disposed in the housing for transferring relatively low pressure inlet port air to outlet port air controllable between relatively low and high pressures;
• first and second meshed timing gears respectively fixed to the first and second rotors for preventing contact of the meshed lobes;
• and an input drive adapted to be rotatably driven by a positive torque about an axis in one drive direction at speeds proportional to speeds of a periodic combustion, torque transmitting engine selectively controllable between idle and maximum speeds;
• the improvement comprising:
• a torsion damping mechanism for transmitting engine torque to the first timing gear, said mechanism including drive and driven means and first and second spring means, said drive and driven means respectively secured for rotation with the input drive and the first timing gear and mounted for limited rotation relative to each other, said first spring means having opposite ends reacting between the drive and driven means in said one drive direction, said second spring means having opposite ends reacting between the drive and driven means in a direction opposite the one drive direction, and said second spring means having a spring rate greater than the spring rate of the first spring means.

A torsion damping mechanism for reducing audible noise of at least first and second continuous mesh gears operating at low loading and rotatably driven by torque in one direction from a periodic combustion engine operating in a speed range near engine idle;

• said mechanism comprising:
• drive and driven means driven in said one direction, mounted for limited relative rotation, respectively driven by the engine and driving the first gear;
• first spring means having opposite ends reacting between the drive and driven means for transmitting torque in said one drive direction for attenuating torsionals, said first spring means having a low torque transmitting capacity relative to full torque transmitting capacity of said gears and having relatively low spring rate for reducing gear tooth rattle of said gears;
• first stop means for contacting a portion of the drive means and arresting said relative rotation in said one drive direction in response to the engine speed being increased a predetermined amount above engine idle and for limiting stored energy in the first spring means;
• second stop means for contacting another portion of the drive means and arresting said relative rotation in a direction opposite said one drive direction, said second spring means having a spring rate greater than the spring rate of the first spring means;
• second spring means having opposite ends reacting between the drive and driven means for absorbing torque in said opposite drive direction, said second spring means being sized to normally prevent engagement of the second stop means.

A torsion damping mechanism for reducing audible noise of at least first and second continuous mesh gears operating at low loading and rotatably driven by torque in one direction from a periodic combustion engine operating in a speed range near engine idle;

• said mechanism comprising:
• drive and driven means driven in said one direction, mounted for limited relative rotation, respectively driven by the engine and driving the first gear;
• first spring means having opposite ends reacting between the drive and driven means for transmitting torque in said one drive direction for attenuating torsionals;
• first stop means for contacting a portion of the drive means and arresting said relative rotation in said one drive direction in response to the engine speed being increased a predetermined amount above engine idle and for limiting stored energy in the first spring means;
• second stop means for contacting another portion of the drive means and arresting said relative rotation in a direction opposite said one drive direction;
• second spring means having opposite ends reacting between the drive and driven means for absorbing torque in said opposite drive direction, said second spring means being sized to normally prevent engagement of the second stop means;
• and
• means for increasing the spring rate of said second spring means in response to torque in said opposite direction exceeding a predetermined amount.