Single ball traction drive assembly

• US 4,700,581 A
• Filed: 11/18/1985
• Issued: 10/20/1987
• Est. Priority Date: 02/05/1982
• Status: Expired due to Fees

• Current Assignee: William R. Loeffler
• Original Assignee: William R. Loeffler
• Inventors: Tibbals, Edward C. Jr.
• Primary Examiner(s): Braun, Leslie
• Assistant Examiner(s): Novais, David
• Application Number:
  US06/799,547
• Time in Patent Office: 701 Days
• Field of Search: 74/200, 74/198, 74/721, 74/208, 74/214, 74/215, 74/216, 74/796
• US Class Current: 476/7
• CPC Class Codes: F16H 15/40 in which two members co-operative by means of balls, or rollers of uniform effective diameter, not mounted on shafts
• CPC Class Codes: Y10S 476/90 Overload release

Abstract

An infinitely variable speed drive mechanism which is specifically adaptable for automotive applications is made up of a single ball or spherical element interpositioned between drive and driven members in opposed facing relation to one another on opposite sides of the ball, each of the drive and driven members having generally annular, frusto-conical surface portions engageable along one of the surfaces of engagement with the ball, and control rollers are mounted under compression against a surface portion of the ball so as to urge the ball into balanced frictional engagement with the drive and driven members while establishing the axis of rotation of the ball and determining the speed ratio imparted through the ball between said drive and driven members.

Claims

1. In a variable drive transmission wherein a pair of independently rotatable input and output members are disposed in spaced facing relation to one another and a speed control mechanism therebetween to regulate the speed ratio between input and output members, said speed control mechanism comprising:

a single variable transmission element of generally spherical shape positioned between said input and output members, said transmission element being rotatable about a variable axis of rotation to impart the torque of said input member to said output member at a variable speed ratio, said input and output members being in the form of generally ring-like members having generally concave surfaces engageable with said transmission element on opposite sides of said transmission element, said output member having a bearing assembly provided with circumferentially spaced, rollable bearing elements between a pair of opposed races, one of said races defining one of said generally ring-like members including said concave surface and being journaled by said bearing elements with respect to the other of said races, internal confronting surfaces of said races having ramp members extending in a circumferential direction and angled inwardly toward said transmission element to cause the inward movement of said bearing elements along said ramp members whereby in response to increases in torque said bearing assembly means is operative to urge said one race against said transmission element and increase the pressure between said transmission element and said input and output members; and

rotatable control roller means establishing surface engagement with said transmission element symmetrically about an imaginary radial line through the center of said transmission element which radial line bisects the angle formed between imaginary radial line extending from the center of said transmission element the points of engagement of said input and output members, said rotatable control roller means including means mounting said control roller means under predetermined compression to exert force against said transmission element in a direction causing said transmission element to bear against a limited surface portion of each of said input and output members, said rotatable control roller means being pivotal about said first imaginary radial line passing therethrough so as to establish an angle of surface engagement with said transmission element to vary the axis of rotation of said transmission element and thereby to vary the speed ratio of said input member to said output member through said transmission element.

2. In a variable speed drive transmission according to claim 1, each of said input and output members being in the form of a ring having an annular annular concave surface portion engageable with said transmission element through a limited surface of engagement in the general form of an ellipse.

3. In a variable speed drive transmission according to claim 2, the surface engagement of said rotatable control roller means with said transmission element being on the order of five times the surface of engagement of said input and output members with said ball.

4. In a variable speed drive transmission according to claim 3, a common housing for said rotatable control roller means and said input members, and a tractant material contained in housing.

5. In a variable transmission according to claim 4, said common housing including circulating means

6. In a variable speed drive transmission according to claim 1, including an output shaft, said output member including clutch means to cause slippage between said output member and said output shaft in response to resistance to turning by said output shaft.

7. In a variable speed drive transmission wherein a pair of independently rotatable input and output members are disposed in facing relation to one another to impart torque from a driving member to a member to be driven, and a speed control mechanism is interposed between said input and output members to regulate the speed ratio between said input and output members, said speed control mechanism comprising:

a single variable speed transmission element in the form of a single ball rotatable about a variable axis of rotation between said input and output members to impart torque from said input member to said output member at a ratio dependent upon the axis of rotation of said ball; and

rotatable control means defined by a pair of rollers disposed in circumferentially spaced relation to one another and engageable with said ball symmetrically about an imaginary plane passing through the center of the ball which plane bisects the angle formed between imaginary radial lines extending from the loci of engagement of said input and output members to the center of the ball, each of said rollers defined by a pair of roller elements mounted for rotation on a common control shaft, said roller elements independently journaled with respect to said control shaft and having outer ball-engaging surface portions inclining inwardly toward one another, pivotal means for pivoting said control rollers in equal increments but in opposite directions to one another with respect to said imaginary plane passing therethrough so as to establish an angle of surface engagement with said ball to control its axis of rotation and thereby determine the speed and torque ratio imparted by said input member to said output member through said ball, said input and output members being in the form of generally ring-like members having generally concave surfaces engageable with said transmission element on opposite sides of said transmission element, said output member having a bearing assembly provided with circumferentially spaced, rollable bearing elements between a pair of opposed races, one of said races defining one of said generally ring-like members including said concave surface and being journaled by said bearing elements with respect to the other of said races, internal confronting surfaces of said races having ramp members extending in a circumferential direction to control the inward movement of said bearing elements along said ramp members whereby in response to increases in torque is operative to urge said one race against said transmission element and increase the pressure between said ball and said input and output members, the included angle formed between imaginary radial lines extending from the center of said ball through the points of engagement of said pair of rollers substantially corresponding to the angle of separation between the loci of engagement of said input and output members with said ball.