Constant velocity ratio universal joint with gothic arch shaped rollers and guide grooves

A constant velocity ratio universal joint of the tripod type comprising an outer joint member (10) having a rotational axis (17) and three guide grooves (20) extending parallel to its rotational axis and equally circumferentially spaced thereabout, each guide groove having opposed side portions;

• and inner joint member (12) disposed inside the outer member (10), having a rotational axis (18) and three arms (13) equally spaced about this rotational axis extending radially into the guide grooves (20) of the outer joint member;
• each arm carrying a roller (21) having an external surface (22) which engages said opposed side portions of the guide groove (20) into which the arm extends so that the roller is constrained to roll therealong;
• each roller being able to rotate about, move lengthwise of, and tilt relative to the arm (13) by which it is carried;
• wherein the cross-sectional shape of said external surface of each roller is of a truncated gothic arch shape, and the cross-sectional shape of each guide groove side portion is of a gothic arch shape different from said truncated gothic arch shape of the roller external surface, said roller external surface and each guide groove side portion having angular contact engagement with one another at two spaced points which lie in said roller external surface and guide groove side portion which are parts of said gothic arch shapes.