Patent Number: 6,253,720

Title: Variable phase coupling

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft comprises a drive member for connection to the crankshaft having helical grooves of a first pitch, a driven member for connection to the engine camshaft having helical grooves of a different pitch facing towards the grooves in the drive member, an intermediate member disposed between the drive and driven members having helical grooves on its inner and outer surfaces, a first set of balls engaging in the pairs of helical grooves comprising the helical grooves in the driven member and the facing grooves on one surface of the intermediate member, a second set of balls engaging in the pairs of helical grooves that comprise the grooves in the drive member and the facing grooves on the other surface of the intermediate member, and means for axially displacing the intermediate member relative to the drive and driven members. The displacement of the intermediate member serves to move the balls relative to the helical grooves in the drive and the driven members so as to vary the phase between the drive and driven members. The helical grooves in each pair have the same pitch as one another and, in order to reduce backlash, the intermediate member is radially compliant and exerts a slight clamping force on the balls.

Inventors: Lancefield; Timothy Mark (Bicester, GB), Methley; Ian (Witney, GB)

Assignee: Mechadyne PLC

International Classification: F01L 1/344 (20060101); F01L 001/344 ()

Expiration Date: 07/03/2018