Universal joint
View Patent ↗A tripot universal joint includes a first rotatable shaft member having a first longitudinal axis and three longitudinal guide channels disposed parallel to the first longitudinal axis, each having two opposing concave side surfaces and a back surface. The joint also includes a rotatable second shaft member having a second longitudinal axis and comprising a spider having three radially extending trunnions equally, each of the trunnions having a convex outer surface disposed within an associated longitudinal guide channel. The joint further includes three rotatable rollers, each rotatably disposed on a convex outer surface of a respective trunnion, each roller having a convex outer surface that is configured for disposition within the concave side surfaces of the longitudinal guide channel with which it is associated for moveable engagement within the channel and an inner surface that is rotatably disposed on the convex surface of the trunnion.
1. A tripot universal joint, comprising:
a first rotatable shaft member having a first longitudinal axis and a housing, the housing having three longitudinal guide channels disposed parallel to the first longitudinal axis and equally spaced circumferentially from one another, each one of the three longitudinal guide channels defined by two opposing concave side surfaces and a back surface, the back surface of each guide channel facing radially inwardly with respect to the first longitudinal axis, the opposing concave side surfaces of each guide channel disposed parallel to one another and separated circumferentially with respect to the outer drive member by the back surface of that guide channel;
a rotatable second shaft member having a second longitudinal axis and comprising a spider having three radially extending trunnions equally spaced circumferentially from one another and on respective coplanar radial axes which intersect the second longitudinal axis at a spider center, each of the trunnions having a convex outer surface disposed within an associated longitudinal guide channel and facing the opposing concave side surfaces thereof; and
three rotatable rollers, each rotatably disposed on the convex outer surface of a respective trunnion and configured to tilt and rotate about the trunnion and to slide along the radial axis of the trunnion, each roller having a convex outer surface that is configured for disposition within the concave side surfaces of the longitudinal guide channel with which it is associated for moveable engagement within the channel and an inner surface that is rotatably disposed on and abutting the convex surface of the trunnion.
2. The universal joint of claim 1 , wherein the moveable engagement of the rollers within the channels comprises rotatable or slidable engagement.
3. The universal joint of claim 1 , wherein the concave side surfaces have side surface curvatures and the outer surfaces of the respective rollers have outer surface curvatures, and the side surface curvatures are less than the outer surface curvatures.
4. The universal joint of claim 3 , wherein the outer surface curvatures and the side surface curvatures establish a single point of contact between the rollers and respective side surfaces.
5. The universal joint of claim 1 , wherein the outer surfaces of the rollers comprise truncated ellipsoids.
6. The universal joint of claim 1 , wherein the inner surfaces of the rollers have inner surface curvatures and the outer surfaces of the respective trunnions have outer surface curvatures, and the inner surface curvatures are less than the outer surface curvatures.
7. The universal joint of claim 6 , wherein the inner surface curvatures of the rollers and the outer surface curvatures of the respective trunnions establish a single point of contact between the rollers and trunnions.
8. The universal joint of claim 1 , wherein the inner surfaces of the rollers have cylindrical shapes that are configured for engagement with the convex outer surfaces of the respective trunnions.
9. The universal joint of claim 8 , wherein the cylindrical shapes are right cylindrical shapes.
10. The universal joint of claim 1 , wherein the inner surface of each roller has a concave shape that is configured for engagement with the convex outer surface of the associated trunnion.
11. The universal joint of claim 10 , wherein the concave shapes of the inner surfaces of the rollers comprise truncated toroids.
12. The universal joint of claim 1 , wherein the outer surfaces of the trunnions comprise truncated toroids.
13. The universal joint of claim 1 , wherein the inner surfaces of the rollers proximate their inner edges further comprise trunnion retention features.
14. The universal joint of claim 13 , wherein the inner surfaces of the rollers are cylindrical and the trunnion retention features comprise raised portions proximate the inner edges.
15. The universal joint of claim 13 , wherein the inner surfaces of the rollers have concave curvatures and the trunnion retention features comprise the concave curvatures proximate the inner edges.
16. The universal joint of claim 1 , wherein the guide channels each have an outer guide wall or a center guide wall, or a combination thereof.
17. The universal joint of claim 1 , wherein the guide channels each have an outer guide wall.
18. The universal joint of claim 1 , wherein the guide channels each have a center guide wall.