GB1040784A - Infinitely variable speed power transmission, especially ball friction transmission - Google Patents

Abstract

1,040,784. Variable-speed friction gear. O. STIEBER. June 19, 1964, No. 25375/64. Heading F2D. A continuously variable friction gear comprises a ball 6 frictionally engaging internal conical surfaces 4a, 5a of offset parallel input and output shafts 4, 5 respectively and shifted to vary the gear ratio by a transverse screwthreaded adjuster 7 which abuts the ball 6 and is arranged on the side nearer to the input shaft 4b than the output shaft. The adjuster 7 may be at right angles to the axes of the input and output shafts, or may be acutely inclined towards the input shaft (Figs. 3 to 5, not shown) and adjustable along a line parallel to the flanks of the conical surfaces 4a, 5a, in contact with the ball. The adjuster abutment 7 may be formed as a flat contact surface or as a roller, or may be a freely journalled disc (Figs. 2 and 4, not shown) providing point contact with the ball 6. In Fig. 5 (not shown) four balls, journalled in a carrier in turn journalled in the adjuster, abut the transmission ball 7. Three or more balls may be in abutment in this manner. Either or both input and output shafts 4b, 5b are axially adjustable in a housing 1 to pre-load the ball 7. The whole arrangement may be turned through 180 degrees such that the abutment control is directly beneath the transmission ball 7. To provide a control range in the order of 1: 9, the diameter of the ball exceeds 60%, preferably 85% to 90% of the maximum diameter of the conical surfaces 4a, 5a which have an included angle of approximately 150 degrees.