VARIABLE SPEED TRANSMISSION

• US 3,707,888 A
• Filed: 07/31/1970
• Issued: 01/02/1973
• Est. Priority Date: 07/31/1970
• Status: Expired due to Term

• Current Assignee: Henry Schottler
• Original Assignee: Henry Schottler
• Inventors: Schottler, Henry
• Primary Examiner(s): Kaufman, Milton
• Assistant Examiner(s): Perry, Thomas C.
• Application Number:
  US05/060,073
• Time in Patent Office: 886 Days
• Field of Search: 74/796,198,200
• US Class Current: 475/189
• CPC Class Codes: F16H 15/503 in which two members co-operate by means of balls or rollers of uniform effective diameter, not mounted on shafts
• CPC Class Codes: F16H 61/664 Friction gearings
• CPC Class Codes: F16H 61/6649 characterised by the means for controlling the torque transmitting capability of the gearing
• CPC Class Codes: Y10S 475/904 Particular mathematical equation

Abstract

A variable speed transmission for transmitting torque to an output shaft at a substantially constant selected speed. Driving balls arranged in constant rolling frictional contact with pairs of inner and outer concentric and axially separable ball races. One pair of races is associated with an input shaft, and the other pair of races is associated with an output shaft. The driving balls and races engage along contact tracks defined on the races and balls to thereby transmit torque between the shafts at a speed ratio determined by the contact tracks. Control means adjusts the axial positioning of one pair of races within a selected range to infinitely vary the contact tracks and thereby vary the speed ratio. Pressure regulator means responds to differential twist torque between the shafts to maintain the balls and races in frictional rolling contact throughout said selected range of adjustment and vary the contact pressure between races and balls in proportion to the output torque.

Claims

1. A variable speed transmission comprising:

first and second rotatable shaft means;

a first pair of annular races defining circular concentric tracks, with one of said first races being axially shiftable and including means to prevent rotation thereof during the operation of the transmission, and the other first race being joined for imparting rotation to said first shaft means;

a second pair of annular races, one of said second races being joined for rotation in an axially fixed position to said second shaft and defining a circular contact track, substantially parallel to said track defined by said other first race, and the other second race defining a concave contact track having a selected radius of curvature;

spherical drive ball means positioned between said races in frictional rolling engagement with said contact tracks to transmit torque between said pairs of races at a speed ratio determined by the relationship of said contact tracks, said ball means having a radius smaller than the radius of curvature of said concave track defined by said other second race;

speed control means for infiNitely varying the axial position of said one first race within a selected range, to move said drive ball means along said concave contact track and between said substantially parallel contact tracks defined on said one second race and said other first race and thereby infinitely vary the relationship between said contact tracks and the resulting speed ratio of said transmission; and

a torque-responsive pressure regulator joining said other second race to said second shaft, said regulator comprising;

an annular cam member joined for rotation with said second shaft and defining cam lobe means extending axially toward said other second race, and cam rolling means positioned between said cam member and said other second race and engagable with said cam lobe means to simultaneously rotate said other second input race in response to the rotation of said second shaft and to urge said second races axially with respect to each other and thereby vary the contact pressure between said drive ball means and said races in proportion to the differential twist torque existing between said second races, said pressure regulator further being arranged to provide relative axial movement of said second races in response to the adjustment of said speed control means which permits said drive ball means to move along said concave track between said parallel contract tracks defined by said one second race and said other first race;

whereby said pressure regulator permits a selected speed ratio to be established by said speed control means and maintains said drive ball means in frictional rolling engagement with said races such that each selected speed ratio established within said range will be substantially constant.

2. A variable speed transmission in accordance with claim 1 wherein said concave track defined by said other second race is opposed to said control race along a diameter of said drive ball means.

3. A variable speed transmission comprising:

input and output shafts;

a pair of annular output races defining circular contact tracks with one of said output races being axially shiftable and including means to prevent rotation thereof during the operation of the transmission, and the other output race being joined for imparting rotation to said output shaft;

a pair of annular input races, one of said input races being joined for rotation in an axially fixed position to said input shaft and defining a circular contact track substantially parallel to said track defined by said other output race, and the other input race defining a concave contact track having a selected radius of curvature;

spherical drive ball means positioned between said races in frictional rolling engagement with said contact tracks to transmit torque between said pairs of races at a speed ratio determined by the relationship of said contact tracks, said ball means having a radius smaller than the radius of curvature of said concave track defined by said other input race;

speed control means for infinitely varying the axial position of said one output race within a selected range, to selectively move the drive ball means along said concave track and between said substantially parallel contact tracks defined on said one input race and said other output race and thereby infinitely vary the relationship between said contact tracks and the resulting speed ratio of said transmission; and

a torque-responsive pressure regulator joining said other input race to said input shaft, said regulator comprising;

an annular cam member joined for rotation with said input shaft and defining cam lobe means extending axially toward said other input race, and cam rolling means positioned between said cam member and said other input race and engagable with said cam lobe means to simultaneously rotate said other input race in response to the rotation of said input shaft and to urge said input races axially with respect to each other and thereby vary the contact pressure between said Drive ball means and said races in proportion to the differential twist torque existing between said input races, said pressure regulator further being arranged to provide relative axial movement of said input races in response to the adjustment of said speed control means which permits said drive ball means to move along said concave track between said parallel contact tracks defined by said one input race and said other output race;

whereby said pressure regulator permits a selected speed ratio to be established by said speed control means and maintains said drive ball means in frictional rolling engagement with said races such that each selected speed ratio established within said range will be substantially constant.

4. A variable speed transmission comprising:

first and second rotatable shaft means;

a first pair of annular races defining circular concentric tracks, with one of said first races being axially shiftable and including means to prevent rotation thereof during the operation of the transmission, and the other first race being joined for imparting rotation to said first shaft means;

a second pair of annular races, one of said second races being joined for rotation in an axially fixed position to said second shaft and defining a circular contact track substantially parallel to said track defined by said other first race, and the other second race defining a concave contact track having a selected radius of curvature;

spherical drive ball means positioned between said races in frictional rolling engagement with said contact tracks to transmit torque between said pair of races at a speed ratio determined by the relationship of said contact tracks, said ball means having a radius smaller than the radius of curvature of said concave track defined by said other second race;

speed control means for infinitely varying the axial position of said one first race within a selected range, to move said drive ball means along said concave contact track and between said substantially parallel contact tracks defined on said one second race and said other first race and thereby infinitely vary the relationship between said contact tracks and the resulting speed ratio of said transmission; and

a torque-responsive pressure regulator means joining said other second race to said second shaft means, said regulator means comprising;

an annular cam member connected for rotation with said second shaft means including a plurality of cam lobes extending axially toward other said other second race, with each lobe defining a pair of symmetrical cam rise surfaces;

annular non-lobed roller track means axially aligned with said cam lobes and joined for rotation with said other second race; and

a plurality of cam rolling means positioned between said cam lobes and said roller track means and engagable with said cam lobes to simultaneously roll along said roller track in a single geometric plane and to rotate said other second race in response to the rotation of said second shaft means and further to urge said second races together for either clockwise or counter-clockwise rotation of said second shaft means;

said pressure regulator thereby varying the contact pressure between said second races and ball means in proportion to the differential twist torque existing between said second races and maintaining said ball means in frictional engagement with said races for each selected speed ratio within said range, so that the selected speed ratio will be maintained substantially constant for each direction of rotation of said second shaft means.