STRESS REDUCTION FOR PULVERIZER MAIN SHAFT VIA FLEXIBLE STRUCTURE
A yoke bushing that reduces the cyclic movement between the main shaft of a ball-and-race type coal pulverizer, thereby resulting in longer shaft life and reduced incidences of shaft failure. The yoke bushing is comprised of a flexible structure that provides individual contact areas which will have, at the same locations, equal stress fields between the main shaft and the yoke bushing.
1 . An assembly comprising an upright rotatable shaft extending into a rotatable yoke, a flexible tubular bushing interposed between the shaft and the yoke, the bushing including spaced upper and lower portions contacting the shaft.
2 . The assembly according to claim 1 , including flexile means connecting the upper and lower portions of the bushing.
3 . The assembly according to claim 2 , wherein the transverse thickness of the flexile means is less than that of the upper and lower portions of the bushing.
4 . The assembly according to claim 2 , wherein the flexile means includes a band bordering upon the yoke.
5 . The assembly according to claim 4 , including an elastomeric material located between the flexile means and the shaft.
6 . The assembly according to claim 2 , wherein the flexile means includes a band medially nested between the shaft and the yoke.
7 . The assembly according to claim 2 , wherein the flexile means includes a band bordering upon the shaft.
8 . The assembly according to claims 4 , 6 , or 7 , wherein the band is formed with perforations.
9 . The assembly according to claim 2 , wherein the flexile means includes a plurality of circularly-spaced vertical rods extending between the upper and lower portions of the bushing.
10 . The assembly according to claim 9 , wherein the rods are equally spaced from one another.
11 . The assembly according to claim 1 , including flexile means interposed between the upper and lower portions of the bushing.
12 . The assembly according to claim 11 , wherein the flexile means includes an elastomeric sleeve.
13 . The assembly according to claim 11 , wherein the flexile means includes a plurality of vertically stacked annular disks.
14 . The assembly according to claim 11 , wherein the flexile means includes a plurality bushing portions.
15 . The assembly according to claim 11 , wherein the flexibility is achieved by an air gap between the upper and lower portions of the bushings.