Co-rotational scroll apparatus with optimized coupling

A co-rotational scroll apparatus comprised of:

• a hermetic shell having a suction pressure portion for containing a suction pressure fluid;
• a first rotatable scroll member disposed in said suction pressure portion, said first scroll member having a first scroll end plate, a first scroll wrap including a first upstanding involute portion disposed on said first scroll end plate, and a drive shaft defining an axis of rotation disposed on said first end plate, said first scroll member being subject to a varying tipping moment as it rotates in operation;
• a second rotatable scroll member disposed in said suction pressure portion, said second scroll member having a second scroll end plate, a second scroll wrap including an upstanding involute portion disposed on said second scroll end plate, said second scroll wrap defining a line, in cooperation with said first scroll wrap, of zero crank angle, and an idler shaft disposed on said second end plate, said idler shaft defining an axis of rotation offset from the axis of rotation of said drive shaft, said second scroll member cooperating with said first scroll member to define a centerline, said centerline being parallel to both said axis of rotation of said drive shaft, and said axis of rotation of said idler shaft and equidistant therebetween, said second scroll member being subject to a varying tipping moment as it rotates in operation;
• selectively positioned means for drivingly coupling said first scroll member and said second scroll member, said coupling means having a center of gravity disposed at a predetermined angle from said line of zero crank angle so that the movement, mass and selective positioning of said coupling, when said scroll apparatus is in operation, produces a moderating moment which proactively enhances the nutational stability of said scroll apparatus by acting in opposition to and reducing the tipping moment to which at least one of said first and said second scroll members is subjected;
• means for rotatably supporting said idler shaft in said suction portion of said hermetic shell;
• and
• means for rotating said first scroll drive shaft.

A refrigeration system for circulating refrigerant in closed loop connection comprised of:

• a condenser for condensing refrigerant to liquid form;
• an expansion device for receiving liquid refrigerant from said condenser and expanding the refrigerant;
• an evaporator for receiving the refrigerant from said expansion device and evaporating the refrigerant to vapor form;
• a compressor for receiving the refrigerant from the evaporator, compressing the refrigerant, and sending the refrigerant to the condenser, said compressor having
• i. a hermetic shell having a suction pressure portion for containing a suction pressure fluid;
• ii. a first scroll member disposed in said suction pressure portion and subject to a varying tipping moment when said compressor is in operation, said first scroll member having a first scroll end plate, a first scroll wrap, said first scroll wrap being an upstanding involute portion disposed on said first scroll end plate, and a drive shaft having an axis of rotation, said drive shaft being disposed on said first end plate;
• iii. a second scroll member disposed in said suction pressure portion and subject to a varying tipping moment when said compressor is in operation, said second scroll member having a second scroll end plate, a second scroll wrap, said second scroll wrap being an involute portion disposed on said second scroll end plate, said second scroll member having an idler shaft disposed on said second end plate, said idler shaft having an axis of rotation offset from said axis of rotation of said drive shaft, said second scroll member cooperating with said first scroll member to define a line of zero crank angle and a centerline, said centerline being parallel to said axis of said drive shaft and said axis of said idler shaft and equidistant therebetween;
• iv. selectively positioned means for drivingly coupling said first scroll member and said second scroll member, said coupling means being of a predetermined mass and having a center of gravity disposed at a predetermined angle from the line of zero crank angle, the selective positioning of said coupling producing a moderating moment which proactively enhances the nutational stability of said scroll compressor by acting in opposition to and reducing the maximum tipping moment to which a selected one of said first and said second scroll members is subjected when said compressor is in operation;
• v. means for rotatably supporting said idler shaft in said suction portion of said hermetic shell;
• and
• vi. means for rotating said first scroll drive shaft.

A method of enhancing the nutational stability of a co-rotational scroll apparatus having a driven scroll member, said driven scroll member having an axis about which it rotates through a cycle of angular positions, said driven scroll member including a first involute scroll wrap, and an idler scroll member having an axis about which it rotates through said cycle of angular positions said idler scroll member including a second involute scroll wrap in interleaving engagement with said first scroll wrap, said drive scroll member being subject to a tipping moment and said idler scroll member being subject to a tipping moment when said scroll apparatus is in operation, said method comprising the steps of:

• determining a line of zero crank angle;
• determining the instantaneous tipping moment to which at least said idler scroll member is subjected at each said angular position when said scroll apparatus is in operation;
• determining the maximum tipping moment to which at least said idler scroll member is subjected when said scroll apparatus is in operation and the angular position at which said maximum tipping moment occurs with respect to said line of zero crank angle;
• determining an angle from said line of zero crank angle at which to dispose a mass for producing a moderating moment for counteracting said maximum tipping moment to which at least said idler scroll member is subjected;
• and
• engaging said drive scroll member and said idler scroll member with coupling means for joint rotation, said coupling means having a predetermined mass and center of gravity disposed at said angle, so that the mass of said coupling means produces said moderating moment for counteracting said maximum tipping moment to which at least said idler scroll member is subjected to when said scroll apparatus is in operation.