CA2034625A1 - Earth boring bit with axially radiussed roller bearing race - Google Patents
Earth boring bit with axially radiussed roller bearing raceInfo
- Publication number
- CA2034625A1 CA2034625A1 CA 2034625 CA2034625A CA2034625A1 CA 2034625 A1 CA2034625 A1 CA 2034625A1 CA 2034625 CA2034625 CA 2034625 CA 2034625 A CA2034625 A CA 2034625A CA 2034625 A1 CA2034625 A1 CA 2034625A1
- Authority
- CA
- Canada
- Prior art keywords
- roller
- race
- cutter
- bearing shaft
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Rolling Contact Bearings (AREA)
- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A bearing shaft roller race that is axially radiussed to have a crowned region underneath the outer end of the roller to minimize abrupt change in the stress imposed upon the race by the ends of the roller to reduce spalling.
The crowned region is tapered beginning about 1/4 inch from the end of the rollers. The taper is about 0.0005 inch deep at a location on the roller race underneath the outermost end of the roller. The taper is a radius which is tangent to the roller race.
A bearing shaft roller race that is axially radiussed to have a crowned region underneath the outer end of the roller to minimize abrupt change in the stress imposed upon the race by the ends of the roller to reduce spalling.
The crowned region is tapered beginning about 1/4 inch from the end of the rollers. The taper is about 0.0005 inch deep at a location on the roller race underneath the outermost end of the roller. The taper is a radius which is tangent to the roller race.
Description
CROSS REFERENCE TO REl~TED APPLlCATlON 203~625 3 This Application is related to an application, Earth Boring Bi~ With 4 Convergent Cutter Bearing, Serial No. 277,61G, filed November 29, 1988 by Eric C. Sullivan et al, U.S. Patent No. 4,899,838 said patent having been 6 assigned to Hughes Tool Company, which is the wholly owned subsidiary of 7 Baker Hughes Incorporated, the assignee of this application.
. ,. : , , .
.. ~.
. .
.
~, ' .
Z~346 BACKGROUND OF'rHE INVENTION
.. ~.
. .
.
~, ' .
Z~346 BACKGROUND OF'rHE INVENTION
3 1. Field of the Invention:
4 This invention relates generally to earth boring bits, especially to lhose having conical cutters supported upon lubricated bearing shafts, the 6 improvement relating to a bearing configuraeion to reduce s~ress on roller 7 bearing races.
8 2. Description of the Prior Art:
9 Earth boring bits typically have conically shaped cutters which are supported on lubricated bearings, some of which use roller bearings. Of the many types of earth boring bits, two are especially significant here:
12 (1) The three cone type used to drill holes in the mining 13 and the oil and gas industry, and 4 (2) Shaft cutter bits which utilize a number of individually mounted conical cutters dispersed across the face of a 6 bit body large enough to drill ventilation and other 17 shafts in mines.
18 For many years it has been comrnon to use what are called "crowned"
19 rollers, which are tapered or radiussed at the end to reduce the stress imposed upon the roller race and thereby reduce spalling of the race. The 21 $ypical crowned roller utilizes a large radius which begins about 1/4 inch from 22 the end of the roller and decreases the diameter of the roller at the end by 23 about 0.001 inch. The radius is usually tangent to the cylindrical surface of 24 the roller.
2 s However, crowning of individual rollers in the above manner increases 2 6 substantially the cost of each individual roller. Further, i$ is unnecessary that 27 both ends of the rollers be crowned. Spalling of the journal roller race 28 generally begins at a point below the outermost end of the roller, meaning at 2 9 the end of the roller nearer to the wall of the borehole.
.
;
- ' , ' ,' ' . '' ~ , , SUM~Y OF THE lNVENTION ~03~6~5 3 It is therefore the general object of the invention to provide an earth 4 boring bit of the type having a rotatable cutter supported on a bearing shaft with improved means to reduce the stress upon the rollers and roller race 6 between the shaft and the cutter.
7 The above and other objects of the invention are achieved by a 8 bearing shaft roller race that is axially radiussed to have a crowned region9 underneath the outer end of the roller to min~mize abrupt change oP loading 0 on the race by the ends of the roller to reduce spalling. I~e crowned regionis tapered beginning about 1/4 inch from the outer end of the rollers. The 2 taper is about 0.0005 inch deep at a location on the roller race underneath 13 the outer end of the roller. The taper is preferably a radius which is tangent 14 to the cylindrical surface of the roller race.
Additional objects, features and advantages of the invention will 16 become apparent in the following description.
.
DES(: I~IPTION OF THE ~RAWINGS
3 FIG. 1 is a longitudinal section of an earth boring bit of the shaft 4 cutter type, which includes the cutter, the bearing shaft, the bearing means and other components such as the seal means.
6 FIG. 2 is an enlarged, fragmentary portion to show in greater detail 7 the configuration of the roller race which includes the improvement of the 8 invention.
.
, , .
- - , . .
, .
.
.
~3~ 5 DE:SCRIPTION OF ~E PREFE~D EMBODIMEN'r 3 The numeral 11 in the drawings designates a bearing shaft which 4 supports a seal retainer 12 and a metal face seal means 13. Spaced outwardly from the metal faced seal 13 is a small roller bearing 14, a ball bearing 15 in a 6 bearing cage 16, a larger or outer roller bearing 17, a seal seat 18, a seal 7 retainer I9 and a metal face seal 36. The bearing shaft 11 includes a thread 8 protector 20, snap ring 219 O-ring 22 and a zirk fitting 23 associated with a 9 lubrication plug 24, one end of which engages the ball bearing 15 to lo cooperatively form a retainer means to confine the conical cutter 26 to the11 bearing shaft. The conical cutter is truncated, having an inner end 27 that is 12 smàller in diameter than the outer end 28. The outer end 28 is normally 13 positioned in the hole closer to the wall of the hole than is the inner end 27.
14 A plurality of sintered tungsten carbide inserts 29 are retained by interference fit in the conical cutter 26 to disintegrate earth formation during6 drilling.
7 The larger and outermost roller bearing 17 (i.e. that nearest-the wall 8 of the hole during drilling) is positioned near the outer, larger end 28 of the 19 cutter 26, resulting in greater forces and stresses being applied to the 2 o associated race. This is the location where spalling is most likely to occur.
21 Referring now to FIG. 2, a ball bearing race 31 is adjacent the 22 outermost roller race 32 in the bearin~ shaft 11. The larger and outermost 23 roller bearings 17 of FIG. 1 engage the roller bearing race 32. The roller 2~ race 32 has a crowned region 33 which extends between the cylindrical portion 32 of the race and a break corner 34 which is shown as a be~lel but is 26 sometimes a radius of about 0.050 inch. The crowned region 33 is a taper, 27 actually an axial extending spherical radius, beginning a distance designated 28 as X in FIG. 2 from the outer end of the location of the end of the roller 29 bearings 17 of FIG. 1, a distance of about 1/4 inch. The end of the roller is normally aligned with the intersection of the break corner 34 and crowned 31 region 33. Further, the taper is a distance of about 0.0005 inch deep as 32 indicated by Y in FIG. 2. This distance Y, which measures the depth of the ;~3~
crowned region, is at the outer end of the rollers 17 shown in FIC:;. 1. The 2 crowned region 33 is preferably defined by a radius R which is tangent to the 3 cylindrical roller race 32 4 A mounting means 35 is provided fs~r rnounting the shaft 11 to the bit(not shown). The truncated, conical shaft cutter 26 is mounted on the 6 bearing shaft 11, the larger diameter of which is positioned generally over the 7 outer roller race 32. Seal means 36 between the cutter and ~he bearing shaft 8 confine the lubricant between the shaft and cutter roller bearing and around g the roller bearing A retainer means, here a ball bearing 15 confined by Ihe o end of the lube plug 24, secures the cutter to the bearing shaft.
The use of a crowned region on the region race beneath the rollers 12 avoids abrupt changes in the stress imposed on the rollers and the roller race 13 There is a significant reduction in stress and a significant reduction of 14 spalling.
When used with a shaft cutter of the type shown in the drawings, only 6 the outermost region of the outer roller race is usually crowned. This is the 17 location of greatest stress and the first place spalling is likely to begin There 18 is usually a greater distribution of force and hence greater stress at the outer 19 end of the cutter, which is nearer the wall of the hole on a larger radius from 2 o the center of the hole, than the inner end of the cutter. The outer roller race 21 is usually larger in diameter and longer than the inner roller race Thus, the 2 2 stress is greater at the outer end of the large roller race.
2 3 While the invention has been shown in only one of its forms, it should24 be apparent to those skilled in the art that it is not thus limited, but is susceptible to various changes and modifications without departing from the 2 6 spirit thereof.
.. ~ . .. .
. -. . ' ~ . ' : . .
- ~. .
. ' ' : ' .
.
8 2. Description of the Prior Art:
9 Earth boring bits typically have conically shaped cutters which are supported on lubricated bearings, some of which use roller bearings. Of the many types of earth boring bits, two are especially significant here:
12 (1) The three cone type used to drill holes in the mining 13 and the oil and gas industry, and 4 (2) Shaft cutter bits which utilize a number of individually mounted conical cutters dispersed across the face of a 6 bit body large enough to drill ventilation and other 17 shafts in mines.
18 For many years it has been comrnon to use what are called "crowned"
19 rollers, which are tapered or radiussed at the end to reduce the stress imposed upon the roller race and thereby reduce spalling of the race. The 21 $ypical crowned roller utilizes a large radius which begins about 1/4 inch from 22 the end of the roller and decreases the diameter of the roller at the end by 23 about 0.001 inch. The radius is usually tangent to the cylindrical surface of 24 the roller.
2 s However, crowning of individual rollers in the above manner increases 2 6 substantially the cost of each individual roller. Further, i$ is unnecessary that 27 both ends of the rollers be crowned. Spalling of the journal roller race 28 generally begins at a point below the outermost end of the roller, meaning at 2 9 the end of the roller nearer to the wall of the borehole.
.
;
- ' , ' ,' ' . '' ~ , , SUM~Y OF THE lNVENTION ~03~6~5 3 It is therefore the general object of the invention to provide an earth 4 boring bit of the type having a rotatable cutter supported on a bearing shaft with improved means to reduce the stress upon the rollers and roller race 6 between the shaft and the cutter.
7 The above and other objects of the invention are achieved by a 8 bearing shaft roller race that is axially radiussed to have a crowned region9 underneath the outer end of the roller to min~mize abrupt change oP loading 0 on the race by the ends of the roller to reduce spalling. I~e crowned regionis tapered beginning about 1/4 inch from the outer end of the rollers. The 2 taper is about 0.0005 inch deep at a location on the roller race underneath 13 the outer end of the roller. The taper is preferably a radius which is tangent 14 to the cylindrical surface of the roller race.
Additional objects, features and advantages of the invention will 16 become apparent in the following description.
.
DES(: I~IPTION OF THE ~RAWINGS
3 FIG. 1 is a longitudinal section of an earth boring bit of the shaft 4 cutter type, which includes the cutter, the bearing shaft, the bearing means and other components such as the seal means.
6 FIG. 2 is an enlarged, fragmentary portion to show in greater detail 7 the configuration of the roller race which includes the improvement of the 8 invention.
.
, , .
- - , . .
, .
.
.
~3~ 5 DE:SCRIPTION OF ~E PREFE~D EMBODIMEN'r 3 The numeral 11 in the drawings designates a bearing shaft which 4 supports a seal retainer 12 and a metal face seal means 13. Spaced outwardly from the metal faced seal 13 is a small roller bearing 14, a ball bearing 15 in a 6 bearing cage 16, a larger or outer roller bearing 17, a seal seat 18, a seal 7 retainer I9 and a metal face seal 36. The bearing shaft 11 includes a thread 8 protector 20, snap ring 219 O-ring 22 and a zirk fitting 23 associated with a 9 lubrication plug 24, one end of which engages the ball bearing 15 to lo cooperatively form a retainer means to confine the conical cutter 26 to the11 bearing shaft. The conical cutter is truncated, having an inner end 27 that is 12 smàller in diameter than the outer end 28. The outer end 28 is normally 13 positioned in the hole closer to the wall of the hole than is the inner end 27.
14 A plurality of sintered tungsten carbide inserts 29 are retained by interference fit in the conical cutter 26 to disintegrate earth formation during6 drilling.
7 The larger and outermost roller bearing 17 (i.e. that nearest-the wall 8 of the hole during drilling) is positioned near the outer, larger end 28 of the 19 cutter 26, resulting in greater forces and stresses being applied to the 2 o associated race. This is the location where spalling is most likely to occur.
21 Referring now to FIG. 2, a ball bearing race 31 is adjacent the 22 outermost roller race 32 in the bearin~ shaft 11. The larger and outermost 23 roller bearings 17 of FIG. 1 engage the roller bearing race 32. The roller 2~ race 32 has a crowned region 33 which extends between the cylindrical portion 32 of the race and a break corner 34 which is shown as a be~lel but is 26 sometimes a radius of about 0.050 inch. The crowned region 33 is a taper, 27 actually an axial extending spherical radius, beginning a distance designated 28 as X in FIG. 2 from the outer end of the location of the end of the roller 29 bearings 17 of FIG. 1, a distance of about 1/4 inch. The end of the roller is normally aligned with the intersection of the break corner 34 and crowned 31 region 33. Further, the taper is a distance of about 0.0005 inch deep as 32 indicated by Y in FIG. 2. This distance Y, which measures the depth of the ;~3~
crowned region, is at the outer end of the rollers 17 shown in FIC:;. 1. The 2 crowned region 33 is preferably defined by a radius R which is tangent to the 3 cylindrical roller race 32 4 A mounting means 35 is provided fs~r rnounting the shaft 11 to the bit(not shown). The truncated, conical shaft cutter 26 is mounted on the 6 bearing shaft 11, the larger diameter of which is positioned generally over the 7 outer roller race 32. Seal means 36 between the cutter and ~he bearing shaft 8 confine the lubricant between the shaft and cutter roller bearing and around g the roller bearing A retainer means, here a ball bearing 15 confined by Ihe o end of the lube plug 24, secures the cutter to the bearing shaft.
The use of a crowned region on the region race beneath the rollers 12 avoids abrupt changes in the stress imposed on the rollers and the roller race 13 There is a significant reduction in stress and a significant reduction of 14 spalling.
When used with a shaft cutter of the type shown in the drawings, only 6 the outermost region of the outer roller race is usually crowned. This is the 17 location of greatest stress and the first place spalling is likely to begin There 18 is usually a greater distribution of force and hence greater stress at the outer 19 end of the cutter, which is nearer the wall of the hole on a larger radius from 2 o the center of the hole, than the inner end of the cutter. The outer roller race 21 is usually larger in diameter and longer than the inner roller race Thus, the 2 2 stress is greater at the outer end of the large roller race.
2 3 While the invention has been shown in only one of its forms, it should24 be apparent to those skilled in the art that it is not thus limited, but is susceptible to various changes and modifications without departing from the 2 6 spirit thereof.
.. ~ . .. .
. -. . ' ~ . ' : . .
- ~. .
. ' ' : ' .
.
Claims (8)
1. An earth boring bit having a cutter with an outer end positioned closest to the wall of a bore hole and an inner end, which comprises:
a bearing shaft;
a bearing shaft roller race;
a plurality of roller bearings disposed around the bearing shaft roller race, each roller having an outer end and an inner end corresponding with the outer and inner ends of the cutter;
a cutter rotatably mounted on the bearing shaft; and a cutter roller race, having an outer end and an inner end to confine the ends of the roller bearings while permitting rotation in the shaft and cutter bearing races, characterized by 3, the bearing shaft roller race having a crowned region underneath the outer ends of the rollers to minimize abrupt changes in stress imposed upon the race by the rollers to reduce spalling.
a bearing shaft;
a bearing shaft roller race;
a plurality of roller bearings disposed around the bearing shaft roller race, each roller having an outer end and an inner end corresponding with the outer and inner ends of the cutter;
a cutter rotatably mounted on the bearing shaft; and a cutter roller race, having an outer end and an inner end to confine the ends of the roller bearings while permitting rotation in the shaft and cutter bearing races, characterized by 3, the bearing shaft roller race having a crowned region underneath the outer ends of the rollers to minimize abrupt changes in stress imposed upon the race by the rollers to reduce spalling.
2. The invention of claim 1 in which the crowned region is tapered beginning about 1/4 inch from the end of the rollers.
3. The invention of claim 2 in which the taper is about 0.0005 inch deep at the end of the roller.
4. The invention of claim 3 in which the taper is a radius tangent to the roller race.
5. An earth boring bit of the shaft cutter type, each cutter having an outer end positioned closest to the wall of a borehole and an inner end, which comprises:
a bearing shaft, mounting means for mounting the shaft to the bit;
an inner and an outer bearing shaft roller race corresponding with the inner and outer ends;
a plurality of roller bearings disposed around the inner and outer bearing shaft roller races;
a truncated, conical shaft cutter rotatably mounted on the bearing shaft, the largest diameter positioned generally over the outer roller race;
an inner and an outer cutter roller race opposite the bearing shaft inner and outer roller races to confine the ends of the roller bearings while permitting rotation in the shaft and cutter bearing races;
means to provide lubricant to the roller bearings; and retainer means to confine the cutter to the bearing shaft, characterized by;
the outer bearing shaft roller race having a crowned region underneath the outer ends of the associated rollers to minimize abrupt changes in stress imposed upon the race by the rollers to reduce spalling.
a bearing shaft, mounting means for mounting the shaft to the bit;
an inner and an outer bearing shaft roller race corresponding with the inner and outer ends;
a plurality of roller bearings disposed around the inner and outer bearing shaft roller races;
a truncated, conical shaft cutter rotatably mounted on the bearing shaft, the largest diameter positioned generally over the outer roller race;
an inner and an outer cutter roller race opposite the bearing shaft inner and outer roller races to confine the ends of the roller bearings while permitting rotation in the shaft and cutter bearing races;
means to provide lubricant to the roller bearings; and retainer means to confine the cutter to the bearing shaft, characterized by;
the outer bearing shaft roller race having a crowned region underneath the outer ends of the associated rollers to minimize abrupt changes in stress imposed upon the race by the rollers to reduce spalling.
6. The invention of claim 5 in which the crowned region is tapered beginning about 1/4 inch from the end of the rollers.
7. The invention of claim 6 in which the taper is about 0.0005 inch deep at the end of the roller.
8. The invention of claim 7 in which the taper is a radius tangent to the roller race.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US47770990A | 1990-02-09 | 1990-02-09 | |
| US477,709 | 1990-02-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2034625A1 true CA2034625A1 (en) | 1991-08-10 |
Family
ID=23897034
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2034625 Abandoned CA2034625A1 (en) | 1990-02-09 | 1991-01-21 | Earth boring bit with axially radiussed roller bearing race |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2034625A1 (en) |
| ZA (1) | ZA91356B (en) |
-
1991
- 1991-01-17 ZA ZA91356A patent/ZA91356B/en unknown
- 1991-01-21 CA CA 2034625 patent/CA2034625A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| ZA91356B (en) | 1992-02-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0775245B1 (en) | Modular rotary drill bit | |
| US5586612A (en) | Roller cone bit with positive and negative offset and smooth running configuration | |
| US4899838A (en) | Earth boring bit with convergent cutter bearing | |
| US4958692A (en) | Downhole stabilizers | |
| US5944125A (en) | Rock bit with improved thrust face | |
| USRE34526E (en) | Two cone bit with non-opposite cones | |
| CA1195319A (en) | Composite floating element thrust bearing | |
| US4260203A (en) | Bearing structure for a rotary rock bit | |
| US4572306A (en) | Journal bushing drill bit construction | |
| US5570750A (en) | Rotary drill bit with improved shirttail and seal protection | |
| EP0317089B1 (en) | Precision roller bearing for rock bits | |
| US7117961B2 (en) | Dynamic seal with soft interface | |
| US4722404A (en) | Drill bit bearing seal | |
| US5381868A (en) | Sealed bearing roller reamer | |
| US20110100722A1 (en) | Rotary roller reamer | |
| WO1982001910A1 (en) | Rotary drill bit | |
| US4316515A (en) | Shaft drill bit with improved cutter bearing and seal arrangement and cutter insert arrangement | |
| US6053264A (en) | Cutter head mounting for drill bit | |
| US3820613A (en) | Roller reamer stabilizer | |
| US5186267A (en) | Journal bearing type rock bit | |
| EP0415519B1 (en) | Dual seal system for rotary drill bit | |
| US4330158A (en) | Rotary rock bit with improved thrust flange | |
| CA2034625A1 (en) | Earth boring bit with axially radiussed roller bearing race | |
| US4572589A (en) | Journal bearing | |
| US5307887A (en) | Earth boring bit with improved thrust bearing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |