Shaft with surface finished ridges
AssigneeApple Inc.
InventorsSina Mobasher Moghaddam, Troy A. Carter, Jonathan L. Hall
Life of this patent
Estimating the term…
Abstract
A ball screw spline actuator includes a shaft, a ball nut, and a ball spline. The shaft includes a helical groove and a spline groove intersecting the helical groove forming intersections having a least one ridge including a first surface finish formed by a first manufacturing operation. The ridge is subsequently reformed through a second manufacturing operation to include a second surface finish to reduce stress concentrations in the ridge from cyclical loading from at least one of the ball nut or the ball spline. In one example, the second manufacturing operation reforms the ridge to include a surface finished edge.
Claims20
A ball screw spline actuator, comprising:
- a shaft having a longitudinal axis, the shaft defining a helical groove extending along the shaft and a spline groove extending along the shaft, with the spline groove intersecting the helical groove at a plurality of intersections each defining a ridge, wherein each of the ridges comprises a radius;
- a ball nut engaged with the helical groove configured to apply a first torque to the shaft about the longitudinal axis;
- and
- a ball spline engaged with the spline groove configured to apply a second torque to the shaft about the longitudinal axis to counteract the first torque to the shaft preventing a rotation of the shaft about the longitudinal axis and allowing the shaft to linearly translate along the longitudinal axis relative to the ball nut and the ball spline.
A ball screw spline actuator, comprising:
- a shaft having a longitudinal axis, the shaft defining a helical groove and a spline groove each having an arcuate cross-section and extending along the shaft, the spline groove intersecting the helical groove at an intersection and defining four ridges, wherein each of the four ridges comprises a radius;
- a ball nut engaged with the helical groove configured to apply a first torque to the shaft about the longitudinal axis;
- and
- a ball spline engaged with the spline groove configured to apply a second torque to the shaft about the longitudinal axis configured to linearly translate the shaft along the longitudinal axis relative to the ball nut and the ball spline and preventing rotation of the shaft about the longitudinal axis.
An actuator comprising:
- a shaft having a longitudinal axis and defining a helical groove extending along the shaft and a spline groove extending along the shaft, the spline groove intersecting the helical groove at an intersection defining a ridge extending toward a center of the intersection, the ridge further comprising:
- curved sidewalls formed by the helical groove and the spline groove, the curved sidewalls converging at an edge forming a radius;
- and
- a ball portion engaged with the helical groove, the spline groove, or a combination thereof and configured to apply a torque to the shaft about the longitudinal axis.
Dependencies are inferred from the claim text.