Structural suspension of radial turret bearings
A structural suspension of radial turret bearing wheels in a turret bearing comprises a rail support structure mounted on a turret bearing support structure, a circular rail mounted to the rail support structure, and a plurality of radial wheels running on the mainly vertical inner side of the rail. The suspension includes a vertical flexible shaft, for each radial wheel, supported by an upper and lower support with a part of the shaft protruding with the radial wheel mounted close to the outer end. The inner side of the rail is a frustum with the shortest radius at the top and an aperture of 2 , and the outer mainly planar contacting surface of the wheel has an angle θ relative to the rotational axis of the wheel, and is overlaid with a convex curvature across the contacting surface.
1. A structural suspension of radial turret bearing wheels in a turret bearing, comprising:
a rail support structure mounted on a turret bearing support structure;
a circular rail mounted to the rail support structure, the rail having a mainly vertical inner side and a top;
a plurality of radial wheels running on the vertical inner side of the rail, the radial wheels each having a mainly planar contacting surface;
a mainly vertical flexible shaft, for each radial wheel being supported by an upper shaft support and a lower shaft support with a part of the vertical flexible shaft protruding like a cantilever with the radial wheel mounted close to an outer end of the vertical flexible shaft,
wherein the vertical inner side of the circular rail is a frustum with a shortest radius at the top,
wherein the outer planar contacting surface of the wheel has an angle θ relative to a rotational axis of the radial wheel, and is overlaid with a convex curvature across the planar contacting surface,
wherein a distance between a radial wheel and the vertical inner side of the rail is adjusted by:
the vertical flexible shaft comprising at least two lockable rotational positions, an upper shaft portion of the vertical flexible shaft having a centerline offset relative to a rotational axis of the shaft.
2. The suspension according to claim 1 wherein the at least two lockable positions are provided by the lower shaft support comprising a shape that mates with a similar shape on a lower end of the shaft in at least two angular positions.
3. The suspension according to claim 2 wherein the shape on the lower shaft support is a hexagon or an octagon.
4. The suspension according to claim 2 wherein the shape on the lower shaft support is a cogwheel with at least two teeth.
5. The suspension according to claim 1 , wherein the rotational axis of the radial wheel is tilting an angle A relative to an unloaded condition of the axis, when the vertical flexible shaft is under maximum load, and wherein an angle E between the vertical inner side of the rail and a tangent of the convex curvature across the planar contacting surface is less than zero at a top for conditions without load and larger than A at a bottom for conditions with maximum load.
6. The suspension according to claim 1 wherein a pipe is mounted between the lower shaft support and the upper shaft support to cover the vertical flexible shaft.
7. The suspension according to claim 1 wherein the radial wheel is supported by a bushing, which is able to slide on the vertical flexible shaft the same distance as a maximum vertical movement of a turret relative to the circular rail under maximum load and a vertical movement imposed by angular deflection A of the radial wheel.
8. The suspension according to claim 1 wherein a flange is mounted on an upper rim of the radial wheel.
9. The suspension according to claim 1 wherein the radial wheel is vertically locked to the circular rail by having a lower flange mounted on a top rim of the radial wheel.
10. The suspension according to claim 1 wherein the outer mainly planar contacting surface of the radial wheel with an angle θ relative to the rotational axis of the radial wheel is overlaid with a convex curvature having a shorter radius at a top of the radial wheel and a longer radius at the bottom of the radial wheel.
11. The suspension according to claim 1 wherein the upper shaft support comprises a spherical bearing assembly comprising a spherical ring with a sliding surface and a spherical ball inside the spherical ring with a material matching the sliding surface of the spherical ring, and a housing comprising a top lid fastened to the housing by bolts.
12. The suspension according to claim 1 wherein a cantilevered length, H 1 , between the upper shaft support and the center of the radial wheel is about three times the length, H 2 , between the lower shaft support and the upper shaft support.
13. The suspension according to claim 1 wherein a cross section of the vertical flexible shaft is tapered downward and upward from a largest diameter d 1 at the upper shaft support, downward to a diameter d 3 at the lower shaft support and upward to a diameter d 2 at a lower side of the radial wheel, wherein d 2 is in the range of 50 to 80% of d 1 and d 3 is in the range of 40 to 60% of d 1 .
14. The suspension according to claim 1 wherein the material of the vertical flexible shaft is a steel alloy comprising Molybdenum and Chrome.