Slew drive gearbox with torque tube
View Patent ↗A slew drive includes a housing, a worm shaft having a worm thread carried within the housing for rotational movement, and a torque tube having an outer diameter and a central socket. The torque tube is carried by the housing for rotational movement perpendicularly to the worm shaft and worm thread. A ring gear section having teeth, is carried by the torque tube so that the teeth extend beyond the outer diameter of the torque tube and engage the worm threads. Rotation of the worm shaft rotates the worm threads engaging the teeth of the ring gear section, thereby rotating the ring gear section which rotates the torque tube relative the housing.
1. A slew drive comprising:
a housing;
a worm shaft having a worm thread carried within the housing for rotational movement, wherein the worm thread comprises a plurality of threads distributed along a longitudinal portion of the worm shaft in an hourglass shape;
a torque tube having an outer diameter and a central socket, the torque tube carried by the housing for rotational movement perpendicular to the worm shaft and the worm thread, wherein the torque tube comprises: (i) an annular body, (ii) a pair of annular extensions spaced apart from each other and extending radially outwardly from the annular body, and (iii) a tab radially extending from one annular extension of the pair of annular extensions; and
a ring gear section having teeth that extend around less than a full circumference of the torque tube, wherein the ring gear section is provided on only one substantially planar face of the tab with the teeth extending beyond the radius of the tab and engaging the worm thread, wherein the ring gear section is located between the pair of annular extensions;
whereby rotation of the worm shaft rotates the worm thread engaging the teeth of the ring gear section with the plurality of threads that is distributed along the longitudinal portion of the worm shaft in the hourglass shape, thereby rotating the ring gear section which rotates the torque tube relative the housing.
2. A slew drive as claimed in claim 1 , wherein the housing further comprises:
an annular portion defining an annular volume encircling a central aperture, the torque tube carried within the annular portion; and
a tubular portion coupled to the annular portion and defining a volume having a longitudinal axis forming a tangent to an outer diameter of the annular portion, the annular volume defined by the annular portion and the volume defined by the tubular portion are in communication, with the volume defined by the tubular portion overlapping the annular volume defined by the annular portion as a chord with respect to the outer diameter of the annular portion, the worm shaft having the worm thread carried within the volume defined by the tubular portion, with at least a portion of the worm thread extending into the annular volume at the chord and engaging the teeth of the ring gear section.
3. A slew drive as claimed in claim 1 , wherein the torque tube further comprises:
an annular inset surface formed at each opposed end of a pair of opposed ends of the annular body;
a bearing element positioned over each opposed end, abutting each annular extension of the pair of annular extensions and forming bearing surfaces; and
a seal member carried at each opposed end and seated in the annular inset surfaces.
4. A slew drive as claimed in claim 1 , further including a drive motor coupled to the worm shaft.
5. A slew drive as claimed in claim 4 , wherein the drive motor is coupled to the worm shaft by a planetary gear assembly.
6. A slew drive as claimed in claim 1 , wherein the ring gear section is formed as a single piece with the tab.
7. A slew drive as claimed in claim 1 , wherein the ring gear section is removably coupled to the tab.
8. A slew drive as claimed in claim 1 , wherein the ring gear section is permanently coupled to the tab.
9. A slew drive as claimed in claim 1 , wherein the ring gear section is located radially offset from and between the pair of annular extensions.
10. A slew drive as claimed in claim 1 , wherein the tab comprises another substantially planar face that is axially opposite to the substantially planar face on which the ring gear section is provided.
11. A slew drive as claimed in claim 1 , wherein the ring gear section comprises a substantially planar portion that is coupled to the substantially planar face of the tab.
12. A slew drive as claimed in claim 11 , wherein the ring gear section comprises another substantially planar portion that is exposed.
13. A slew drive comprising:
a gearbox including:
a housing having a tubular portion and an annular portion, the annular portion defining an annular volume encircling a central aperture, the tubular portion coupled to the annular portion and defining a volume having a longitudinal axis forming a tangent to an outer diameter of the annular portion, the annular volume defined by the annular portion and the volume defined by the tubular portion are in communication, with the volume defined by the tubular portion overlapping the annular volume defined by the annular portion as a chord with respect to the outer diameter of the annular portion;
a worm shaft having a worm thread carried within the volume defined by the tubular portion, wherein at least a portion of the worm thread extends into the annular volume at the chord, wherein the worm thread comprises a plurality of threads distributed along a longitudinal portion of the worm shaft in an hourglass shape;
a torque tube having an outer diameter and a central socket, the torque tube carried by the housing for rotational movement within the annular portion of the housing, wherein the torque tube comprises: (i) an annular body, (ii) a pair of annular extensions spaced apart from each other and extending radially outwardly from the annular body, and (iii) a tab radially extending from one annular extension of the pair of annular extensions; and
a ring gear section having teeth that extend around less than a full circumference of the torque tube, wherein the ring gear section is provided on only one substantially planar face of the tab with the teeth extending beyond the radius of the tab and engaging the portion of the worm thread extending into the annular volume at the chord, wherein the ring gear section is located between the pair of annular extensions; and
a drive motor coupled to the worm shaft.
14. A slew drive as claimed in claim 13 , wherein the torque tube further comprises:
an annular inset surface formed at each opposed end of a pair of opposed ends of the annular body;
a bearing element positioned over each opposed end, abutting each annular extension of the pair of annular extensions; and
a seal member carried at each opposed end and seated in the annular inset surfaces.
15. A slew drive as claimed in claim 13 , wherein the ring gear section is formed as a single piece with the tab.
16. A slew drive as claimed in claim 13 , wherein the ring gear section is removably coupled to the tab.
17. A slew drive as claimed in claim 13 , wherein the ring gear section is permanently coupled to the tab.
18. A slew drive as claimed in claim 13 , wherein the drive motor is coupled to the worm shaft by a planetary gear assembly.