Friction gearing continuously variable transmission

• US 6,390,945 B1
• Filed: 04/13/2001
• Issued: 05/21/2002
• Est. Priority Date: 04/13/2001
• Status: Expired due to Fees

• Current Assignee: Ratio Disc Corp.
• Original Assignee: Ratio Disc Corp.
• Inventors: Young, James Robert
• Primary Examiner(s): Marmor, Charles A
• Assistant Examiner(s): Parekh, Ankur
• Application Number:
  US09/834,714
• Time in Patent Office: 403 Days
• Field of Search: 475/186, 475/191, 475/195, 476/47, 476/50, 476/54, 476/56, 476/57
• US Class Current: 475/186
• CPC Class Codes: F16H 15/12 in which one or each member is duplicated, e.g. for obtaining better transmission, for lessening the reaction forces on the bearings

Abstract

Continuously variable transmission consists of two rolling friction planetaries with a transversely mounted disk interposed between wheels of the planetaries. Varying the position of the disk varies the speed ratio. Transmitted forces urge an idler wheel into a converging space between the internal ring and the wheel in contact with the disk so as to establish contact forces as a function of transmitted torque. Ratio change is made easy by temporarily moving the disk laterally and utilizing the resultant change in contact position to establish a velocity vector which urges the disk toward a new position using only the power being transmitted. Well-known gear systems are used to extend the ratio range. Well-known tractants, or friction enhancing lubricants are used as lubricants to prevent wear yet maximize capacity.

Claims

1. A friction gearing transmission, comprising:

driving and driven means;

a friction gearing planetary;

said planetary includes a rotatable ring, a rotatable sun wheel and at least two rotatable planet wheels, a support for said sun wheel, and a support for said planet wheels;

a disc interposed between the sun wheel and a first planet wheel of said at least two planet wheels;

said disc being rotatably mounted about an axis transverse to the axes of the sun wheel and the at least two planet wheels, and in friction contact with said sun wheel and said first planet wheel;

means to cause normal forces to exist between adjacent rotatable members of said planetary and of said disc; and

,

whereby, power may be transmitted in either direction between the ring and the disc, and in either direction of rotation, at a ratio substantially determined by the size of the ring and the position of the disc.

2. The friction gearing transmission of claim 1, further including:

means to vary the position of the axis of said disc with respect to the contact between said disc with said planet wheel and said sun wheel, thereby, varying the rotation ratio between said ring and said disc.

3. The friction gearing transmission of claim 2, further including:

a second friction gearing planetary, comprising a rotatable ring, a rotatable sun wheel and at least two rotatable planet wheels, a support for said sun wheel, and a support for said planet wheels;

said second friction gearing planetary being positioned on the opposite side of said disc to the first friction gearing planetary, and positioned so that the disc is interposed between the sun wheel and a planet wheel of said second friction gearing planetary;

means to cause normal forces to exist between adjacent rotatable members of said second friction gearing planetary and said disc; and

,

whereby power may be transmitted from one of said planetary rings to the other, through the disc and planet members at a rotation ratio substantially determined by the size of the rings and their respective positions with regard to the axis of said disc, and in either direction of rotation.

4. The friction gearing transmission of claim 3, further including:

means to vary the position of the axis of said disc with respect to the two planetaries,

thereby changing the relative rotation ratio between the rings of the planetaries and achieving the effects of a continuously variable transmission.

5. The friction gearing transmission of claim 1 wherein said means to cause normal forces comprises:

means to establish a preload, when no torque is being transmitted;

two converging wedge shaped gaps formed by a radial gap between the peripheral surface of said sun wheel and the internal surface of said ring, a second planet wheel of said at least two planet wheels positioned in one wedge shape gap and in friction contact with the sun wheel and with the ring, and a third planet wheel of said at least two planet wheels positioned in the other wedge shaped gap and in friction contact with the sun wheel and the ring;

means to vary the position of said second planet wheel, in response to the transmitted torque, so that said second planet wheel is urged further into said one wedge shaped gap when the torque is in a first direction; and

said second planet wheel is prevented from movement out of said one wedge shaped gap when the torque is in the opposite direction;

means to vary the position of said third planet wheel, in response to transmitted torque, so that said third planet wheel is urged further into said other wedge shaped gap when the torque is in the opposite direction; and

said third planet wheel is prevented from moving out of said other wedge shaped gap when the torque is in the first direction,

thereby creating forces between all friction members, substantially in proportion to the transmitted torque, in such a manner as to prevent damaging slippage between members transmitting power.

6. The friction gearing transmission of claim 5, wherein, said preload results from means to urge at least one of the planet wheels into one of the wedge shaped gaps between the sun wheel and the ring of said planetary.

7. The friction gearing transmission of claim 1, further including:

means to move the axis of said disc parallel to the plane of said planetary so as to create a force, in the area of contact, urging the disc either closer to, or further from, the plane of said planetary;

means to permit movement of said disc axis either closer to or further from the plane of said planetary,

thereby utilizing the power being transmitted through the disc to aid in changing the rotation ratio between the disc and the ring.

8. The friction gearing transmission of claim 7, wherein said means to move the axis of said disc includes:

an eccentric mounted to the rotatable means of the disc;

and means to move said eccentric.

9. The friction gearing transmission of claim 8, wherein:

said eccentric is rotationally movable by a lever;

said lever being capable of being set to a new position and causing power through the unit to drive the disc axis until it aligns with the new position of said lever,

thereby using the position of the lever to determine a new rotation ratio which is approached asymptotically.

10. The friction gearing transmission of claim 1, further comprising a friction enhancing lubricant which includes polymers of trifluorochloroethylene.

11. The friction gearing transmission of claim 1, further comprising a friction enhancing fused alicyclic lubricant.

12. The friction gearing transmission of claim 3, wherein the ring of the first planetary and the ring of the second planetary rotate in opposite directions.

13. The friction gearing transmission of claim 3, wherein the ring of the first planetary and the ring of the second planetary rotate in the same direction.

14. The friction gearing transmission of claim 4, where at least one of said rotatable members of said planetaries and of said disc are mounted in sliding hydrodynamic bearings, rather than rolling contact bearings.

15. The friction gearing transmission of claim 1, wherein the planetary members include:

a sun wheel having friction contacts on at least two different circumferences, where at least one of said circumferences is in contact with a circumference of a planet wheel which is intermediate the sun wheel and the ring, and one of said friction contacts is with the disc;

at least one intermediate planet wheel having at least one friction contact with the ring and one friction contact with the sun;

the planet wheel between the disc and the ring having at least two different circumferences, where at least one circumference is in friction contact with the ring and a different circumference in friction contact with the disc;

the ring having at least one inner surface for contacting the planets and an annular clearance for the circumference of the planet wheel which is in friction contact with the disc,

thereby reducing the number of stress cycles on the planetary members, for longer life, and, also, thereby permitting design freedom to choose surface curvatures which overcome hydroplaning and maximize traction.