Variable length shaft assembly with a lash bushing

A method of assembling a shaft assembly, said method comprising:

• making a bushing as a sheet-like element with a longitudinal extent and having a plurality of longitudinally extending wedge-shaped portions, a plurality of spring portions, a plurality of hinge portions, a first projection and a second projection, said step of making a bushing including interconnecting pairs of adjacent wedge-shaped portions with one of the spring portions to form longitudinally extending lobes, interconnecting adjacent lobes with one of the hinge portions, creating the first projection at the first end portion of the bushing to extend transverse to the longitudinal extent of the bushing, and creating the second projection at a second end portion of the bushing to extend at least partially transverse to the longitudinal extent of the bushing;
• rolling the bushing into a tube-like element such that the hinge portions are flexed and the first projection of the bushing extends radially outward to provide a flange;
• providing a hollow first shaft which has an open end and an inner surface defining a plurality of elongate interior grooves with longitudinally extending sides;
• providing a second shaft which has an end portion and an exterior surface defining a plurality of elongate exterior projections with longitudinally extending sides;
• positioning the bushing within the first shaft, including positioning each of the hinge portions to extend between adjacent grooves of the first shaft, positioning each of the wedge-shaped portions in engagement with one of the sides of one of the elongate grooves, positioning one of the spring portions adjacent to a closed end of each of the elongate grooves, and positioning the first projection of the bushing such that it overlies the open end of the first shaft to prevent the first end portion of the bushing from entering the first shaft;
• and
• positioning the second shaft within the bushing, including positioning each side of each of the elongate projections in engagement with one of the wedge-shaped portions.

A shaft assembly comprising:

• a tubular first shaft extending along an axis, said first shaft having an open end and an interior surface having a plurality of elongate grooves extending parallel to the axis;
• a second shaft extending along the axis, said second shaft having an end portion located within said first shaft, said end portion of said second shaft having an exterior surface having a plurality of elongate projections extending parallel to the axis and extending into said grooves;
• and
• bushing means for transmitting torque between said first and second shafts, said bushing means having bearing portions located in said grooves for transmitting torque between said projections and said interior surface defining said grooves, said bushing means including flange means for preventing axial movement of said bushing means relative to said first shaft, said flange means abutting against said open end of said first shaft, each of said grooves of said first shaft has a remote end located at a distance from said open end of said first shaft, said interior surface of said first shaft having a tapering step with an enlarged inner diameter located adjacent to said remote end of said grooves, said bushing means including tangs for resisting removal of said bushing means from said first shaft in an axial direction, said tangs extending into said step of said first shaft.

A shaft assembly comprising:

• a tubular first shaft extending along an axis, said first shaft having an open end and an interior surface having a plurality of elongate grooves extending parallel to the axis;
• a second shaft extending along the axis, said second shaft having an end portion located within said first shaft, said second shaft having an exterior surface having a plurality of elongate projections extending parallel to the axis and mating with said elongate grooves, said exterior surface of said second shaft and said interior surface of said first shaft defining an inwardly tapered gap on each side of each elongate projection;
• and
• bushing means for transmitting torque between said first and second shafts, said bushing means extending into said first shaft, said bushing means including a plurality of wedge segments each located within a respective one of said tapered gaps for resisting relative rotation between said first and second shafts, said bushing means including spring means for biasing each wedge segment into said respective tapered gap and into engagement with said exterior surface and said interior surface, at least some of said wedge segments being slidable transverse to the axis along said respective tapered gap and slidable relative to said exterior surface and said interior surface;
• each of said elongate grooves having an end located at a distance from said open end of said first shaft, said interior surface having a tapering step with an enlarged inner diameter located at said ends of said elongate grooves, said bushing means including restraint means for preventing axial movement of said bushing means relative to said first shaft, said restraint means including tang means for preventing removal of said bushing means from said first shaft along an axial direction, said tang means extending into said tapering step of said first shaft.