U.S. patent application number 14/369583 was filed with the patent office on 2014-12-11 for split sleeves for rolling cutters.
The applicant listed for this patent is SMITH INTERNATIONAL, INC.. Invention is credited to Michael George Azar, Jibin Shi, Youhe Zhang.
Application Number | 20140360792 14/369583 |
Document ID | / |
Family ID | 48698598 |
Filed Date | 2014-12-11 |
United States Patent
Application |
20140360792 |
Kind Code |
A1 |
Azar; Michael George ; et
al. |
December 11, 2014 |
SPLIT SLEEVES FOR ROLLING CUTTERS
Abstract
A cutter assembly may include a multi-piece split sleeve, an
inner cutting element having a groove or protrusion formed in a
side surface thereof and disposed in the multi-piece split sleeve,
and at least one component interfacing at least a portion of the
groove or the protrusion to limit axial movement of the inner
cutting element with respect to the multi-piece split sleeve, in
which the multiple pieces of the split sleeve are joined together
at an overlapping joint.
Inventors: |
Azar; Michael George; (The
Woodlands, TX) ; Shi; Jibin; (Spring, TX) ;
Zhang; Youhe; (Spring, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SMITH INTERNATIONAL, INC. |
Houston |
TX |
US |
|
|
Family ID: |
48698598 |
Appl. No.: |
14/369583 |
Filed: |
December 27, 2012 |
PCT Filed: |
December 27, 2012 |
PCT NO: |
PCT/US2012/071701 |
371 Date: |
June 27, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61581542 |
Dec 29, 2011 |
|
|
|
Current U.S.
Class: |
175/432 |
Current CPC
Class: |
E21B 10/5735 20130101;
E21B 10/62 20130101; E21B 10/43 20130101 |
Class at
Publication: |
175/432 |
International
Class: |
E21B 10/573 20060101
E21B010/573 |
Claims
1. A cutter assembly, comprising: a multi-piece split sleeve; an
inner cutting element having a groove or protrusion formed in a
side surface thereof and disposed in the multi-piece split sleeve;
and at least one component interfacing at least a portion of the
groove or the protrusion to limit axial movement of the inner
cutting element with respect to the multi-piece split sleeve,
wherein the multiple pieces of the split sleeve are joined together
at an overlapping joint.
2. The cutter assembly of claim 1, wherein the inner cutting
element is rotatable within the multi-piece split sleeve.
3. The cutter assembly of claim 1, wherein the sleeve split
comprises at least two inner surface radii, a first sleeve radius
being smaller than a second sleeve radius, wherein the inner
cutting element comprises a side surface having at least two radii,
a first cutting element radius being smaller than a second cutting
element radius and axially positioned between a cutting face and
the second cutting element radius, and wherein the sleeve is
adjacent to at least a portion of the inner cutting element side
surface, such that the first sleeve radius mates with the first
cutting element radius and the second sleeve radius mates with the
second cutting element radius.
4. The cutter assembly of claim 1, wherein a groove or protrusion
extend circumferentially around at least a portion of the inner
cutting element.
5. (canceled)
6. The cutter assembly of claim 1, wherein the interfacing
component is the sleeve.
7. The cutter assembly of claim 1, wherein the interfacing
component is a separate component from the sleeve.
8. The cutter assembly of claim 1, wherein the multi-piece split
sleeve extends around only a portion of the circumference of the
inner cutting element.
9. The cutter assembly of claim 1, wherein the multi-piece split
sleeve extends around greater than 180 degrees of the inner cutting
element and up to the entire circumference of the inner cutting
element.
10. (canceled)
11. The cutter assembly of claim 1, wherein the inner cutting
element comprises a smooth and curved transition between
neighboring surfaces defining different inner cutting element
radii.
12. (canceled)
13. The cutter assembly of claim 1, wherein the inner cutting
element consists of diamond.
14. The cutter assembly of claim 1, wherein a bottom surface of the
inner cutting element has curvature.
15. A cutting tool, comprising: a tool body; a plurality of blades
extending from the tool body; at least one cutter pocket formed in
the plurality of blades; at least one cutter assembly of claim 1
disposed in the at least one cutter pocket.
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. (canceled)
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. The cutting tool of claim 15, wherein the overlapping joint is
sufficient to resist capillary flow of braze therethrough.
28. (canceled)
29. (canceled)
30. The cutting tool of claim 15, wherein at least one piece of the
multi-piece sleeve is cast into the blade.
31. The cutting tool of claim 15, wherein at least one piece of the
multi-piece sleeve is brazed into the cutter pocket.
32. A cutting tool, comprising: a tool body; a plurality of blades
extending from the tool body; at least one rotatable cutting
element disposed on at least one blade, wherein the rotatable
cutting element has a groove formed in a side surface thereof; and
at least one retention element interfacing the rotatable cutting
element at the groove and limiting axial movement of the rotatable
cutting element, wherein the rotatable cutting element comprises a
smooth and curved transition between the groove and the neighboring
side surface.
33. The cutting tool of claim 32, wherein the rotatable cutting
element comprises a smooth and curved transition between the side
surface and a bottom surface of the rotatable cutting element.
34. The cutting tool of claim 32, wherein the rotatable cutting
element is disposed in a sleeve, where the sleeve is brazed in a
cutter pocket formed in the at least one blade.
35. The cutting tool of claim 34, wherein the sleeve is a
multi-piece sleeve.
36. The cutting tool of claim 35, wherein the multiple pieces of
the split sleeve are joined together at an overlapping joint.
37. The cutting tool of claim 35, wherein the multi-piece sleeve
comprises a sleeve component and the cutter pocket.
38. The cutting tool of claim 32, wherein the rotatable cutting
element is disposed in a cutter pocket.
39. A cutting tool, comprising: a tool body; a plurality of blades
extending from the tool body; at least one rotatable cutting
element disposed in a cutter pocket on at least one blade, wherein
the rotatable cutting element has a groove formed in a side surface
thereof; and at least one retention element interfacing the
rotatable cutting element; wherein the at least one retention
element extends greater than 180 degrees and less than 360 degrees
around the rotatable cutting element.
40. The cutting tool of claim 39, wherein the at least one
retention element comprises a protrusion that mates with the groove
and limits axial movement of the rotatable cutting element.
41. The cutting tool of claim 39, wherein the at least one
retention element comprises a multi-piece sleeve.
42. The cutting tool of claim 41, wherein at least one piece of the
multi-piece sleeve is cast into the blade.
43. The cutting tool of claim 39, wherein at least one piece of the
multi-piece sleeve is brazed into the blade.
44. The cutting tool of claim 38, wherein the at least one
retention mechanism comprises a sleeve and a portion of the cutter
pocket.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] Embodiments disclosed herein relate generally to
polycrystalline diamond compact cutters and bits or other cutting
tools incorporating the same. More particularly, embodiments
disclosed herein relate to cutters retained within a sleeve and/or
rolling cutters having curved transitions and bits or other cutting
tools incorporating the same.
[0003] 2. Background Art
[0004] Various types and shapes of earth boring bits are used in
various applications in the earth drilling industry. Earth boring
bits have bit bodies which include various features such as a core,
blades, and cutter pockets that extend into the bit body or roller
cones mounted on a bit body, for example. Depending on the
application/formation to be drilled, the appropriate type of drill
bit may be selected based on the cutting action type for the bit
and its appropriateness for use in the particular formation.
[0005] Drag bits, often referred to as "fixed cutter drill bits,"
include bits that have cutting elements attached to the bit body,
which may be a steel bit body or a matrix bit body formed from a
matrix material such as tungsten carbide surrounded by a binder
material. Drag bits may generally be defined as bits that have no
moving parts. However, there are different types and methods of
forming drag bits that are known in the art. For example, drag bits
having abrasive material, such as diamond, impregnated into the
surface of the material which forms the bit body are commonly
referred to as "impreg" bits. Drag bits having cutting elements
made of an ultra hard cutting surface layer or "table" (typically
made of polycrystalline diamond material or polycrystalline boron
nitride material) deposited onto or otherwise bonded to a substrate
are known in the art as polycrystalline diamond compact ("PDC")
bits.
[0006] PDC bits drill soft formations easily, but they are
frequently used to drill moderately hard or abrasive formations.
They cut rock formations with a shearing action using small cutters
that do not penetrate deeply into the formation. Because the
penetration depth is shallow, high rates of penetration are
achieved through relatively high bit rotational velocities.
[0007] PDC cutters have been used in industrial applications
including rock drilling and metal machining for many years. In PDC
bits, PDC cutters are received within cutter pockets, which are
formed within blades extending from a bit body, and are typically
bonded to the blades by brazing to the inner surfaces of the cutter
pockets. The PDC cutters are positioned along the leading edges of
the bit body blades so that as the bit body is rotated, the PDC
cutters engage and drill the earth formation. In use, high forces
may be exerted on the PDC cutters, particularly in the
forward-to-rear direction. Additionally, the bit and the PDC
cutters may be subjected to substantial abrasive forces. In some
instances, impact, vibration, and erosive forces have caused drill
bit failure due to loss of one or more cutters, or due to breakage
of the blades.
[0008] In a typical application, a compact of polycrystalline
diamond (PCD) for other ultrahard material) is bonded to a
substrate material, which is typically a sintered metal carbide to
form a cutting structure. PCD comprises a polycrystalline mass of
diamonds (typically synthetic) that are bonded together to form an
integral, tough, high-strength mass or lattice. The resulting PCD
structure produces enhanced properties of wear resistance and
hardness, making PCD materials extremely useful in aggressive wear
and cutting applications where high levels of wear resistance and
hardness are desired.
[0009] A PDC cutter is conventionally formed by placing a sintered
carbide substrate into the container of a press. A mixture of
diamond grains or diamond grains and catalyst binder is placed atop
the substrate and treated under high pressure, high temperature
conditions. In doing so, metal binder (often cobalt) migrates from
the substrate and passes through the diamond grains to promote
intergrowth between the diamond grains. As a result, the diamond
grains become bonded to each other to form the diamond layer, and
the diamond layer is in turn integrally bonded to the substrate.
The substrate often comprises a metal-carbide composite material,
such as tungsten carbide-cobalt. The deposited diamond layer is
often referred to as the "diamond table" or "abrasive layer."
[0010] An example of a prior art PDC bit having a plurality of
cutters with ultra hard working surfaces is shown in FIGS. 1A and
1B. The drill bit 100 includes a bit body 110 having a threaded
upper pin end 111 and a cutting end 115. The cutting end 114
typically includes a plurality of ribs or blades 120 arranged about
the rotational axis L (also referred to as the longitudinal or
central axis) of the drill bit and extending radially outward from
the bit body 210. Cutting elements, or cutters, 150 are embedded in
the blades 120 at predetermined angular orientations and radial
locations relative to a working surface and with a desired back
rake angle and side rake angle against a formation to be
drilled.
[0011] A plurality of orifices 116 are positioned on the bit body
110 in the areas between the blades 120, which may be referred to
as "gaps" or "fluid courses," The orifices 116 are commonly adapted
to accept nozzles. The orifices 116 allow drilling fluid to be
discharged through the bit in selected directions and at selected
rates of flow between the blades 120 for lubricating and cooling
the drill bit 100, the blades 120 and the cutters 150. The drilling
fluid also cleans and removes the cuttings as the drill bit 100
rotates and penetrates the geological formation. Without proper
flow characteristics, insufficient cooling of the cutters 150 may
result in cutter failure during drilling operations. The fluid
courses are positioned to provide additional flow channels for
drilling fluid and to provide a passage for formation cuttings to
travel past the drill bit 100 toward the surface of a wellbore (not
shown).
[0012] Referring to FIG. 1B, a top view of a prior art PDC bit is
shown. The cutting face 118 of the bit shown includes six blades
120. Each blade includes a plurality of cutting elements or cutters
generally disposed radially from the center of cutting face 118 to
generally form rows. Certain cutters, although at differing axial
positions, may occupy radial positions that are in similar radial
position to other cutters on other blades.
[0013] Cutters are conventionally attached to a drill bit or other
downhole tool by a brazing process. In the brazing process, a braze
material is positioned between the cutter and the cutter pocket.
The material is melted and, upon subsequent solidification, bonds
(attaches) the cutter in the cutter pocket. Selection of braze
materials depends on their respective melting temperatures, to
avoid excessive thermal exposure (and thermal damage) to the
diamond layer prior to the bit (and cutter) even being used in a
drilling operation. Specifically, alloys suitable for brazing
cutting elements with diamond layers thereon have been limited to
only a couple of alloys which offer low enough brazing temperatures
to avoid damage to the diamond layer and high enough braze strength
to retain cutting elements on drill bits.
[0014] A significant factor in determining the longevity of PDC
cutters is the exposure of the cutter to heat. Conventional
polycrystalline diamond is stable at temperatures of up to
700-750.degree. C. in air, above which observed increases in
temperature may result in permanent damage to and structural
failure of polycrystalline diamond. This deterioration in
polycrystalline diamond is due to the significant difference in the
coefficient of thermal expansion of the binder material, cobalt, as
compared to diamond. Upon heating of polycrystalline diamond, the
cobalt and the diamond lattice will expand at different rates,
which may cause cracks to form in the diamond lattice structure and
result in deterioration of the polycrystalline diamond. Damage may
also be due to graphite formation at diamond-diamond necks leading
to loss of microstructural integrity and strength loss, at
extremely high temperatures.
[0015] Exposure to heat (through brazing or through frictional heat
generated from the contact of the cutter with the formation) can
cause thermal damage to the diamond table and eventually result in
the formation of cracks (due to differences in thermal expansion
coefficients) which can lead to spalling of the polycrystalline
diamond layer, delamination between the polycrystalline diamond and
substrate, and conversion of the diamond back into graphite causing
rapid abrasive wear. As a cutting element contacts the formation, a
wear flat develops and frictional heat is induced. As the cutting
element is continued to be used, the wear flat will increase in
size and further induce frictional heat. The heat may build-up that
may cause failure of the cutting element due to thermal mis-match
between diamond and catalyst discussed above. This is particularly
true for cutters that are immovably attached to the drill bit, as
conventional in the art.
[0016] Accordingly, there exists a continuing need to develop ways
to extend the life of a cutting element.
SUMMARY OF INVENTION
[0017] This summary is provided to introduce a selection of
concepts that are further described below in the detailed
description. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used as an aid in limiting the scope of the claimed
subject matter.
[0018] According to one aspect, embodiments disclosed herein relate
to a cutter assembly that includes a multi-piece split sleeve, an
inner cutting element having a groove or protrusion formed in a
side surface thereof and disposed in the multi-piece split sleeve,
and at least one component interfacing at least a portion of the
groove or the protrusion to limit axial movement of the inner
cutting element with respect to the multi-piece split sleeve, in
which the multiple pieces of the split sleeve are joined together
at an overlapping joint.
[0019] According to another aspect, embodiments disclosed herein
relate to a cutting tool that includes a tool body, a plurality of
blades extending from the tool body, at least one cutter pocket
formed in the plurality of blades, at least one cutter assembly
disposed in the at least one cutter pocket, the at least one cutter
assembly including a multi-piece split sleeve, an inner cutting
element having a groove or protrusion formed in a side surface
thereof and disposed in the multi-piece split sleeve, and at least
one component interfacing at least a portion of the groove or the
protrusion to limit axial movement of the inner cutting element
with respect to the multi-piece split sleeve, in which the multiple
pieces of the split sleeve are jointed together at an overlapping
joint, in which the multi-piece sleeve is brazed into the at least
one cutter pocket.
[0020] According to another aspect, embodiments disclosed herein
relate to a cutting tool that includes a tool body, a plurality of
blades extending from the tool body, at least one rotatable cutting
element disposed on at least one blade, in which the rotatable
cutting element has a groove formed in a side surface thereof, and
at least one retention element interfacing the rotatable cutting
element at the groove and limiting axial movement of the rotatable
cutting element, in which the rotatable cutting element includes a
smooth and curved transition between the groove and the neighboring
side surface.
[0021] Other aspects and advantages of the claimed subject matter
will be apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIGS. 1A and 1B show a side and top view of a conventional
drag bit.
[0023] FIGS. 2A and 2B show a side and top cross-sectional view of
an inner cutting element disposed within a multi-piece split
sleeve, in which the sleeve extends around only a portion of the
circumference of the inner cutting element, according to
embodiments disclosed herein.
[0024] FIGS. 3A and 3B show a side and top cross-sectional view of
an inner cutting element disposed within a multi-piece split
sleeve, in which the sleeve extends around the entire circumference
of the inner cutting element, according to embodiments disclosed
herein.
[0025] FIG. 4 shows a cross-sectional view of an inner cutting
element disposed within a sleeve, in which the inner cutting
element includes a smooth and curved transition between the groove
and the neighboring side surface, according to embodiments
disclosed herein.
[0026] FIG. 5 shows a cross-sectional view of an inner cutting
element disposed within a sleeve, in which a bottom surface of the
inner cutting element has curvature, according to embodiments
disclosed herein.
[0027] FIGS. 6A and 6B show a side and top view of an inner cutting
element having a groove formed in a side surface thereof, in which
the protrusion extends around only a portion of the inner cutting
element, according to embodiments disclosed herein.
[0028] FIG. 7 shows a cross-sectional view of an inner cutting
element disposed within a sleeve, in which an outer diameter of the
sleeve is equal to an outer diameter of the inner cutting element,
according to embodiments disclosed herein.
[0029] FIG. 8 shows a cross-sectional view of an inner cutting
element disposed within a sleeve, in which the inner cutting
element includes a smooth and curved transition between the groove
and the neighboring side surface, and in which an outer diameter of
the sleeve is equal to an outer diameter of the inner cutting
element, according to embodiments disclosed herein.
[0030] FIG. 9 shows a perspective view of a cutter assembly
disposed in a cutter pocket, according to embodiments of the
present disclosure.
[0031] FIG. 10 shows an exploded view of a cutter assembly and a
cutter pocket, according to embodiments of the present
disclosure.
[0032] FIG. 11 shows a cross-sectional view of a cutter assembly
disposed in a cutter pocket, according to embodiments of the
present disclosure.
[0033] FIG. 12 shows a perspective view of a partial sleeve
according to embodiments of the present disclosure.
[0034] FIG. 13 shows a perspective view of a partial sleeve
according to embodiments of the present disclosure.
DETAILED DESCRIPTION
[0035] In one aspect, embodiments disclosed herein relate to
polycrystalline diamond compact cutters being retained on a drill
bit or other cutting tool by a mechanism that interfaces the cutter
along a side surface thereof such that the cutter is free to rotate
about its longitudinal axis or is mechanically retained therein.
Embodiments of the present disclosure also relate to a cutting
element having curved transitional surfaces that is retained within
a sleeve structure or directly within a cutter pocket.
Illustrations of each of these embodiments are shown.
[0036] Certain terms are used throughout the following description
and claims refer to particular features or components. As those
having ordinary skill in the art will appreciate, different persons
may refer to the same feature or component by different names. This
document does not intend to distinguish between components or
features that differ in name but not function. The figures are not
necessarily to scale. Certain features and components herein may be
shown exaggerated in scale or in somewhat schematic form and some
details of conventional elements may not be shown in interest of
clarity and conciseness.
[0037] In the following discussion and in the claims, the terms
"including" and "comprising" are used in an open-ended fashion, and
thus should be interpreted to mean "including, but not limited to .
. . . " Further, the terms "axial" and "axially" generally mean
along or substantially parallel to a central or longitudinal axis,
while the terms "radial" and "radially" generally mean
perpendicular to a central, longitudinal axis.
[0038] Referring to FIGS. 2A and 2B, an inner cutting element 200
disposed within a multi-piece split sleeve 210, in which the sleeve
210 extends around only a portion of the circumference of the inner
cutting element 200, in accordance with embodiments disclosed
herein, is shown.
[0039] In one or more embodiments, the inner cutting element 200
may be a rotatable cutting element that may be rotatable (about its
axis L) within the sleeve 210. Further, in one or more embodiments,
the inner cutting element 200 may include an ultrahard layer 202
that forms a cutting face and edge and a substrate 204. In one or
more embodiments, the inner cutting element 200 may have a groove
206 formed in a side surface thereof. As shown in FIG. 2A, the
inner cutting element 200 has the groove 206 formed in the
substrate 204.
[0040] In one or more embodiments, at least one component may
interface at least a portion of the groove 206 to limit axial
movement of the inner cutting element 200 with respect to the
sleeve 210. As shown, the sleeve 210 includes a protrusion 208 that
is configured to engage or interface with the groove 206 of the
inner cutting element 200. In one or more embodiments, the axial
movement or displacement of the inner cutting element 200 may be
limited by this engagement between the at least one component
(e.g., the protrusion 208 of the sleeve 210) and the groove 206 of
the inner cutting element 200.
[0041] Alternatively, in one or more embodiments, the inner cutting
element 200 may include a protrusion (not shown) formed on a side
surface thereof instead of the groove 206. Further, in one or more
embodiments, the sleeve 210 may include a corresponding groove (not
shown) configured to engage or interface with the protrusion of the
inner cutting element 200 instead of the protrusion 208. As such,
in one or more embodiments, axial movement or displacement of the
inner cutting element 200 with respect to the sleeve 210 may be
limited by an engagement between the protrusion of the inner
cutting element 200 and the groove of the sleeve 210.
[0042] In one or more embodiments, the groove 206 of the inner
cutting element 200 may extend circumferentially around the entire
inner cutting element 200, and the corresponding protrusion 208 of
the sleeve 210 may also extend circumferentially around the entire
extent of the sleeve 210. Alternatively, in one or more
embodiments, the groove 206 of the inner cutting element 200 may
extend around only a portion of the inner cutting element 200. In
other words, in one or more embodiments, the groove 206 of the
inner cutting element 200 may not extend around the entire
circumference of the inner cutting element 200.
[0043] As discussed above, one or more embodiments may include a
protrusion (not shown) formed on the inner cutting element 200
instead of the groove 206, and the sleeve 210 may include a
corresponding groove (not shown) configured to engage with the
protrusion of the inner cutting element 200 instead of the
protrusion 208. As such, in one or more embodiments, the protrusion
formed on the inner cutting element 200 may extend
circumferentially around the entire cutting element 200, and the
corresponding groove of the sleeve 210 may also extend
circumferentially around the entire extent of the sleeve 210.
Alternatively, in one or more embodiments, the protrusion formed on
the inner cutting element 200 may extend around only a portion of
the inner cutting element 200. In other words, in one or more
embodiments, the protrusion of the inner cutting element 200 may
not extend around the entire circumference of the inner cutting
element 200.
[0044] In one or more embodiments, although the groove 206 (or
protrusion) of the inner cutting element 200 may extend around only
a portion of the inner cutting element 200 and may not extend
around the entire circumference of the inner cutting element 200,
the corresponding protrusion 208 (or groove) of the sleeve 210 may
extend around the entire circumference of the inner cutting element
200. This may allow the inner cutting element 200 to be rotatable
within the sleeve 210 while still restricting axial movement or
displacement of the inner cutting element 200 with respect to the
sleeve 210.
[0045] Alternatively, as will be discussed below, in one or more
embodiments, the corresponding protrusion 208 (or groove) of the
sleeve 210 may also only extend around a portion of sleeve 210 and
may be formed to engage with the groove 206 (or protrusion) of the
inner cutting element 200. This may restrict both rotation of the
inner cutting element 200 within the sleeve 210 and axial movement
or displacement of the inner cutting element 200 with respect to
the sleeve 210.
[0046] Furthermore, as shown in FIG. 2A, the sleeve split of the
split sleeve 210 may include at least two inner surface radii: a
first sleeve radius RS1 being smaller than a second sleeve radius
RS2. In one or more embodiments, the inner cutting element 200 may
include a side surface having at least two radii: a first cutting
element radius RC1 being smaller than a second cutting element
radius RC2 and axially positioned between a cutting face the
ultrahard layer 202 of the inner cutting element 200) and the
second cutting element radius RC2. In one or more embodiments, the
sleeve 210 is adjacent to at least a portion of the inner cutting
element 200 side surface (e.g., a surface of the substrate 204),
such that the first sleeve radius RS1 mates or engages with the
first cutting element at radius RC1) such that first sleeve radius
RS1 mates or engages with first cutting element radius RC1 and the
second sleeve radius RS2 mates or engages with the second cutting
element radius RC2.
[0047] Thus, in one or more embodiments, the interfacing component
interfacing at least a portion of the groove or the protrusion of
an inner cutting element to limit axial movement of the inner
cutting element may be the sleeve 210. For example, as shown in
FIG. 2A, the interfacing component to limit axial movement of the
inner cutting element 200 with respect to the sleeve 210 is the
protrusion 208 of the sleeve 210. Alternatively, in one or more
embodiments, the interfacing component may be a separate component
from the sleeve. For example, an alternate interfacing component
(not shown), such as retention balls or a pin, may be disposed
between the sleeve 210 and the inner cutting element 200 that may
limit axial movement or displacement of the inner cutting element
200 relative to the sleeve 210.
[0048] As shown in FIG. 2B, the multi-piece split sleeve 210 is a
two-piece split sleeve. Those having ordinary skill in the art will
appreciate that the multi-piece split sleeve may be formed from
more than two pieces. For example, in one or more embodiments, the
multi-piece split sleeve may be a three-piece, four-piece,
five-piece, or more, split sleeve.
[0049] Further, as shown in FIG. 2B, the two pieces of the split
sleeve 210 are joined together at an overlapping joint 212. As
discussed above, in one or more embodiments, the multi-piece split
sleeve may be formed from two or more pieces. As such, in one or
more embodiments, an overlapping joint (e.g., the overlapping joint
212) may be formed where any pieces of the split sleeve 210 are
joined together or engaged at multiple sets of interfacing surfaces
(each set of interfacing surfaces angled with respect to one
another) instead a single set of mating parallel surfaces.
Generally, mating, parallel surfaces may assist in capillary flow
of a braze material into a gap between the surface that may be
formed when the parallel surfaces are close enough to assist
capillary attraction because an adhesive force between a solid and
a liquid being greater than cohesive forces within the liquid. As
such, an overlapping joint (e.g., the overlapping joint 212) may be
sufficient to resist capillary flow of braze material between the
pieces of the split sleeve 210 when the sleeve is brazed in a
cutter pocket in a bit or other downhole cutting tool. As shown in
FIG. 2B, the overlapping joint 212 has three sets of mating
surfaces, with each set being substantially perpendicular to the
adjacent set(s). However, more or less sets of mating surfaces and
other angles may be used to create an overlapping joint.
[0050] In one or more embodiments, the overlapping joint 212 may
run substantially parallel to a line (not shown) that is tangent to
the circumference inner cutting element 200. In one or more
embodiments, the overlapping joint 212 may be substantially
parallel to a line (not shown) that is tangent to the circumference
of the split sleeve 210. Alternatively, in one or more embodiments,
the overlapping joint 212 may not necessarily be parallel to a line
that is tangent to the circumference of the inner cutting element
200 or tangent to the circumference of the split sleeve 210. For
example, in one or more embodiments, the overlapping joint 212 may
be angled or slanted and may not be parallel to a line that is
tangent to the circumference of the inner cutting element 200 or
tangent to the circumference of the split sleeve 210.
[0051] Furthermore, as shown in FIG. 2B, the multi-piece split
sleeve 210 may extend around only a portion of the circumference of
the inner cutting element 200. In one or more embodiments, the
sleeve 210 may extend around greater than 180 degrees of the inner
cutting element. In other words, in one or more embodiments, the
sleeve 210 may extend at least 180 degrees around the circumference
of the inner cutting element 200. This may allow the inner cutting
element that is disposed within the sleeve 210 to be secured within
the sleeve 210 without the sleeve 210 extending around the entire
circumference of the inner cutting element 200. In a particular
embodiment, the sleeve 210 may extend anywhere from greater than
180 degrees up to 360 degrees around the inner cutting element.
Other embodiments, circumferential extent of the sleeve may be from
any of a lower limit of 180, 190, 225, 270, or 315 degrees to any
of an upper limit of 225, 270, 315, or 360 degrees, with any lower
limit being use with any upper limit.
[0052] Referring to FIGS. 3A and 3B, an inner cutting element 300
disposed within a multi-piece split sleeve 310, in which the sleeve
310 extends around the entire circumference of the inner cutting
element 300, in accordance with embodiments disclosed herein, is
shown.
[0053] In one or more embodiments, the inner cutting element 300
may be a rotatable cutting element that may be rotatable about its
axis L within the sleeve 310. Further, in one or more embodiments,
the inner cutting element 300 may include an ultrahard layer 302
and a substrate 304. In one or more embodiments, the inner cutting
element 300 may have a groove 306 formed in a side surface thereof.
As shown, the inner cutting element 300 has the groove 306 formed
in the substrate 304.
[0054] In one or more embodiments, at least one component may
interface at least a portion of the groove 306 to limit axial
movement of the inner cutting element 300 with respect to the
sleeve 310. As shown, the sleeve 310 includes a protrusion 308 that
is configured to engage or interface with the groove 306 of the
inner cutting element 300. However, as discussed above, other
interfacing components may be used as well. In one or more
embodiments, the axial movement or displacement of the inner
cutting element 300 may be limited by this engagement between the
at least one component (e.g., the protrusion 308 of the sleeve 310)
and the groove 306 of the inner cutting element 300. As discussed
above with respect to FIGS. 2A-B, mating groove 306 and/or
protrusion 308 may around the entire circumference of inner cutting
element 300 or some lesser portion.
[0055] As shown, the sleeve 310 extends around the entire
circumference of the inner cutting element 300. Further, as shown,
the sleeve 310 is a two-piece split sleeve with two overlapping
joints 312. As discussed above, an overlapping joint (e.g., the
overlapping joints 312) may be formed where any pieces of the split
sleeve 310 are joined together or engaged. Further, as discussed
above, those having ordinary skill in the art will appreciate that
the multi-piece split sleeve may be formed from more than two
pieces. For example, in one or more embodiments, the multi-piece
split sleeve may be a three-piece, four-piece, five-piece, or more,
split sleeve. Furthermore, as discussed above, an overlapping joint
(e.g., the overlapping joint 312), similar to the one described
with respect to FIGS. 2A-B may be provided at joining of the
multiple pieces of sleeve that is overlapping in an amount
sufficient to resist capillary flow of braze material between the
pieces of the split sleeve 310. Further, while the embodiment
illustrated in FIG. 2B only possesses a single overlapping joint
212, the embodiment illustrated in FIG. 3B includes two overlapping
joints 312, one at each point at which the multiple sleeve pieces
are joined together.
[0056] Referring to FIG. 4, an inner cutting element 400 disposed
within a sleeve 410 (optionally a multi-piece sleeve, as described
above), in which the inner cutting element 400 includes a smooth
and curved transition 407 between a groove 406 and a neighboring
side surface, in accordance with embodiments disclosed herein, is
shown.
[0057] In one or more embodiments, the inner cutting element 400
may be a rotatable cutting element that may be rotatable within the
sleeve 410. Further, in one or more embodiments, the inner cutting
element 400 may include an ultrahard layer 402 and a substrate 404.
In one or more embodiments, the inner cutting element 400 may have
a groove 406 formed in a side surface thereof. As shown, the inner
cutting element 400 has the groove 406 formed in the substrate
404.
[0058] In one or more embodiments, at least one component may
interface at least a portion of the groove 406 to limit axial
movement of the inner cutting element 400 with respect to the
sleeve 410. As shown, the sleeve 410 includes a protrusion 408 that
is configured to engage or interface with the groove 406 of the
inner cutting element 400. In one or more embodiments, the axial
movement or displacement of the inner cutting element 400 may be
limited by this engagement between the at least one interfacing
component (e.g., the protrusion 408 of the sleeve 410) and the
groove 406 of the inner cutting element 400.
[0059] As shown, the inner cutting element 400 includes smooth and
curved transitions 407 between the groove 406 and the neighboring
side surface, e.g., an outer surface of the substrate 404.
Accordingly, in one or more embodiments, the sleeve 410 includes
corresponding smooth and curved transitions between the protrusion
408 and the neighboring side surfaces, e.g., an inner surface of
the sleeve 410, to engage or interface with the inner cutting
element 400.
[0060] As discussed above, in one or more embodiments, the inner
cutting element 400 may include a protrusion (not shown) formed on
a side surface thereof instead of the groove 406. Further, in one
or more embodiments, the sleeve 410 may include a corresponding
groove (not shown) configured to engage or interface with the
protrusion of the inner cutting element 400 instead of the
protrusion 408. As such, in one or more embodiments, axial movement
or displacement of the inner cutting element 400 with respect to
the sleeve 410 may be limited by an engagement between the
protrusion of the inner cutting element and the groove of the
sleeve 410.
[0061] Accordingly, in one or more embodiments, the inner cutting
element 400 may include a smooth and curved transition between a
protrusion formed on a side surface thereof and the neighboring
side surface and/or curved side surfaces. Further, in one or more
embodiments, the sleeve 410 may include corresponding smooth and
curved transitions between the groove of the sleeve 410 and the
neighboring side surfaces and/or curved side surface to engage or
interface with the inner cutting element 400. In one or more
embodiments, the side surface of the inner cutting element is a
continuously curved surface. Optionally, the inner cutting element
400 may also include smooth and curved transitions 411 between the
side surface, e.g., an outer surface of the substrate 404, and the
bottom surface 409 of the inner cutting element.
[0062] Those having ordinary skill in the art will appreciate that
the smooth and curved transitions discussed above with regard to
the inner cutting element 400 and the sleeve 410 may of any radius
known in the art. In other words, embodiments disclosed herein may
include smooth and curved transitions having any radius of
curvature known in the art. Further, those having ordinary skill in
the art will appreciate that the smooth and curved transitions
discussed above are not limited to circular curves and arcs. For
example, the smooth and curved transitions discussed above may be
elliptical, or otherwise irregular, in profile, such that the
smooth or curved transitions do not include sharp edges or corners.
As used herein, "smooth and curved transitions" refer to
transitions between surfaces that do not include sharp edges or
corners.
[0063] As the inner cutting element 400 may be rotatable within the
sleeve 410, the smooth and curved transitions 407 between the
groove 406 and the neighboring side surfaces may reduce friction
between the inner cutting element 400 and the sleeve 410. Reduced
friction between the inner cutting element 400 and the sleeve 410
may extend the life of the inner cutting element 400, as the inner
cutting element 400 is exposed to external forces and conditions
that may force the inner cutting element 400 against the sleeve
410, axially, and may also force the inner cutting element 400 to
rotate within the sleeve 410.
[0064] Referring to FIG. 5, an inner cutting element 500 disposed
within a sleeve 510 (optionally a multi-piece sleeve, as described
above), in which a bottom surface. 509 of the inner cutting element
500 has curvature, in accordance with embodiments disclosed herein,
is shown.
[0065] In one or more embodiments, the inner cutting element 500
may be a rotatable cutting element that may be rotatable within the
sleeve 510. Further, in one or more embodiments, the inner cutting
element 500 may include an ultrahard layer 502 and a substrate 504.
In one or more embodiments, the inner cutting element 500 may have
a groove 506 formed in a side surface thereof. As shown, the inner
cutting element 500 has the groove 506 formed in the substrate
504.
[0066] In one or more embodiments, at least one component may
interface at least a portion of the groove 506 to limit axial
movement of the inner cutting element 500 with respect to the
sleeve 510. As shown, the sleeve 510 includes a protrusion 508 that
is configured to engage or interface with the groove 506 of the
inner cutting element 500. In one or more embodiments, the axial
movement or displacement of the inner cutting element 500 may be
limited by this engagement between the at least one component
(e.g., the protrusion 508 of the sleeve 510) and the groove 506 of
the inner cutting element 500.
[0067] As shown, the inner cutting element 500 includes smooth and
curved transitions 511 between the side surface, e.g., an outer
surface of the substrate 504, and the bottom surface 509 of the
inner cutting element. Accordingly, in one or more embodiments, the
sleeve 510 includes corresponding smooth and curved transitions
between an inner side surface of the sleeve 510 and the neighboring
inner bottom surface of the sleeve 510 to engage or interface with
the curved bottom surface 509 of the inner cutting element 500.
[0068] Further, as shown, the bottom surface 509 of the inner
cutting element 500 has curvature. In other words, in one or more
embodiments, the bottom surface 509 of the cutting element 500 is a
curved surface. As shown, the bottom surface 509 of the cutting
element 500 is a curved surface and is convex in shape. In one or
more embodiments, the inner surface of the sleeve 510 that may
engage the bottom surface 509 of the inner cutting element 500 may
not be conformed to the curved bottom surface 509 of the inner
cutting element 500. In other words, although the bottom surface
509 of the inner cutting element 500 may be curved and convex, the
contacting surface of the sleeve 510 may not necessarily be curved
or concave. Rather, in one or more embodiments, the contacting
surface of the sleeve 510 may be straight such that contact between
the bottom surface 509 of the inner cutting element 500 and the
sleeve 510 is minimized.
[0069] Alternatively, in one or more embodiments, the contacting
surface of the sleeve 510 may be a curved surface, but may curve
away, or in an opposite direction, to the curved bottom surface 509
of the inner cutting element 500 such that contact and surface area
between the inner cutting element 500 and the sleeve 510 is
minimized. Other examples of cutting elements with curved or
conic-shaped surfaces are included in U.S. Provisional Application
No. 61/479,183, which is herein incorporated by reference in its
entirety.
[0070] As the inner cutting element 500 may be rotatable within the
sleeve 510, the curved bottom surface 509 of the inner cutting
element 500 may minimize the surface area of the bottom surface 509
that contacts the sleeve 510. The surface area of contact between
the bottom surface 509 of the inner cutting element 500 and the
sleeve 510 may be minimized by creating a point of contact between
the bottom surface 509 of the inner cutting element 500 and the
sleeve 510, as opposed to the entire bottom surface 509 contacting
the sleeve 510. Minimization of the surface area of the bottom
surface 509 of the inner cutting element 500 that may contact the
inner surface of the sleeve 510 may result in reduced friction
between the inner cutting element 500 and the sleeve 510. As
discussed above, reduced friction between the inner cutting element
500 and the sleeve 510 may extend the life of the inner cutting
element 500, as the inner cutting element 500 is exposed to
external forces and conditions that may force the inner cutting
element 500 against the sleeve 510, axially, and may also force the
inner cutting element 500 to rotate within the sleeve 510.
[0071] In one or more embodiments, one or more ball bearings or
roller bearings (not shown) may be disposed along the outer
diameter of the inner cutting element 500 and/or op the bottom
surface 509 of the inner cutting element 500 to minimize friction
between the inner cutting element 500 and the sleeve 510.
[0072] Referring to FIGS. 6A and 6B, an inner cutting element 600
having a protrusion 606 formed on a side surface thereof, in which
the groove 606 extends around only a portion of the inner cutting
element 600, is shown.
[0073] In one or more embodiments, the inner cutting element 600
may include an ultrahard layer 602 and a substrate 604. In one or
more embodiments, the inner cutting element 600 may have the groove
606 formed in a side surface thereof. As shown, the inner cutting
element 600 has the groove 606 formed in the substrate 604, where
groove only extends around a portion of the circumference of the
inner cutting element 600. Cutting element 600 may be retained in a
sleeve 610 (optionally a multi-piece sleeve, as described
above).
[0074] In one or more embodiments, at least one interfacing
component may interface at least a portion of the groove 606 to
limit axial movement of the inner cutting element 600 with respect
to the sleeve 610. In one or more embodiments, the sleeve 610 may
include a protrusion (not shown) that is configured to engage or
interface with the groove 606 of the inner cutting element 600. In
one or more embodiments, the axial movement or displacement of the
inner cutting element 600 may be limited by this engagement between
the at least one interfacing component (e.g., the protrusion of the
sleeve 610) and the groove 606 of the inner cutting element
600.
[0075] In one or more embodiments, the corresponding protrusion (or
groove) of the sleeve 610 may not extend around the entire
circumference of the inner cutting element and may be formed to
engage with the groove 606 (or protrusion) of the inner cutting
element 600. In other words, in one or more embodiments, the
dimensions of the protrusion of the sleeve 610 may substantially
match the dimensions of the groove 606 of the inner cutting element
600, such that the protrusion of the sleeve 610 may be formed to
interface or engage with the corresponding groove 606 formed in the
inner cutting element 600. This may restrict both rotation of the
inner cutting element 600 within the sleeve 610 and axial movement
or displacement of the inner cutting element 600 with respect to
the sleeve 610.
[0076] Referring to FIG. 7, an inner cutting element 700 disposed
within a sleeve 710 (optionally, a multi-piece sleeve, as discussed
above), in which an outer diameter DS of the sleeve 710 is equal to
an outer diameter DC of the inner cutting element 700, is
shown.
[0077] In one or more embodiments, the inner cutting element 700
may include an ultrahard layer 702 and a substrate 704. In one or
more embodiments, the inner cutting element 700 may have the groove
706 formed in a side surface thereof. As shown, the inner cutting
element 700 has the groove 706 formed in the substrate 704.
[0078] In one or more embodiments, at least one interfacing
component may interface at least a portion of the groove 706 to
limit axial movement of the inner cutting element 700 with respect
to the sleeve 710. In one or more embodiments, the sleeve 710 may
include a protrusion 708 that is configured to engage or interface
with the groove 706 of the inner cutting element 700. In one or
more embodiments, the axial movement or displacement of the inner
cutting element 700 may be limited by this engagement between the
at least one component (e.g., the protrusion 708 of the sleeve 710)
and the groove 706 of the inner cutting element 700.
[0079] As shown, the inner cutting element 700 is disposed within
the sleeve 710. In one or more embodiments, the inner cutting
element 700 may be a rotatable cutting element that may be
rotatable within the sleeve 710. As shown, the outer diameter DS of
the sleeve 710 is substantially equal to the outer diameter DC of
the inner cutting element 700.
[0080] As shown in FIG. 8, an inner cutting element 800 disposed
within a sleeve 810 (optionally a multi-piece sleeve, as described
above), in which the inner cutting element 800 includes a smooth
and curved transition 807 between a groove 806 and a neighboring
side surface, and in which an outer diameter DS of the sleeve 810
is equal to an outer diameter DC of the inner cutting element 800,
in accordance with embodiments disclosed herein, is shown.
[0081] In one or more embodiments, the inner cutting element 800
may be a rotatable cutting element that may be rotatable within the
sleeve 810. Further, in one or more embodiments, the inner cutting
element 800 may include an ultrahard layer 802 and a substrate 804.
In one or more embodiments, the inner cutting element 800 may have
the groove 806 formed in a side surface thereof. As shown, the
inner cutting element 800 has the groove 806 formed in the
substrate 804.
[0082] In one or more embodiments, at least one component may
interface at least a portion of the groove 806 to limit axial
movement of the inner cutting element 800 with respect to the
sleeve 810. As shown, the sleeve 810 includes a protrusion 808 that
is configured to engage or interface with the groove 806 of the
inner cutting element 800. In one or more embodiments, the axial
movement or displacement of the inner cutting element 800 may be
limited by this engagement between the at least one interfacing
component (e.g., the protrusion 808 of the sleeve 810) and the
groove 806 of the inner cutting element 800. As shown, the outer
diameter DS of the sleeve 810 is substantially equal to the outer
diameter DC of the inner cutting element 800.
[0083] Further, as shown, the inner cutting element 800 includes
smooth and curved transitions 807 between the groove 806 and the
neighboring side surface, e.g., an outer surface of the substrate
804. Accordingly, in one or more embodiments, the sleeve 810
includes corresponding smooth and curved transitions between the
protrusion 808 and the neighboring side surfaces, e.g., an inner
surface of the sleeve 810, to engage or interface with the inner
cutting element 800.
[0084] As discussed above, in one or more embodiments, the inner
cutting element 800 may include a protrusion (not shown) formed on
a side surface thereof instead of the groove 806. Further, in one
or more embodiments, the sleeve 810 may include a corresponding
groove (not shown) configured to engage or interface with the
protrusion of the inner cutting element 800 instead of the
protrusion 808. As such, in one or more embodiments, axial movement
or displacement of the inner cutting element 800 with respect to
the sleeve 810 may be limited by an engagement between the
protrusion of the inner cutting element and the groove of the
sleeve 810.
[0085] Accordingly, in one or more embodiments, the inner cutting
element 800 may include a smooth and curved transition between a
protrusion formed on a side surface thereof and the neighboring
side surface and/or curved side surfaces. Further, in one or more
embodiments, the sleeve 810 may include corresponding smooth and
curved transitions between the groove of the sleeve 810 and the
neighboring side surfaces and/or curved side surface to engage or
interface with the inner cutting element 800. In one or more
embodiments, the side surface of the inner cutting element is a
continuously curved surface. Optionally, the inner cutting element
800 may also include smooth and curved transitions 811 between the
side surface, e.g., an outer surface of the substrate 804, and the
bottom surface 809 of the inner cutting element.
[0086] Those having ordinary skill in the art will appreciate that
the smooth and curved transitions discussed above with regard to
the inner cutting element 800 and the sleeve 810 may of any radius
known in the art. In other words, embodiments disclosed herein may
include smooth and curved transitions having any radius of
curvature known in the art. Further, those having ordinary skill in
the art will appreciate that the smooth and curved transitions
discussed above are not limited to circular curves and arcs. For
example, the smooth and curved transitions discussed above may be
elliptical, or otherwise irregular, in profile, such that the
smooth or curved transitions do not include sharp edges or corners.
As used herein, "smooth and curved transitions" refer to
transitions between surfaces that do not include sharp edges or
corners.
[0087] As the inner cutting element 800 may be rotatable within the
sleeve 810, the smooth and curved transitions 807 between the
groove 806 and the neighboring side surfaces may reduce friction
between the inner cutting element 800 and the sleeve 810. Reduced
friction between the inner cutting element 800 and the sleeve 810
may extend the life of the inner cutting element 800, as the inner
cutting element 800 is exposed to external forces and conditions
that may force the inner cutting element 800 against the sleeve
810, axially, and may also force the inner cutting element 800 to
rotate within the sleeve 810.
[0088] In one or more embodiments, a cutting tool may include a
tool body, a plurality of blades extending from the tool body, at
least one cutter pocket formed in the plurality of blades, at least
one cutter assembly disposed in the at least one cutter pocket, the
at least one cutter assembly including a multi-piece split sleeve,
an inner cutting element having a groove or protrusion formed in a
side surface thereof and disposed in the multi-piece split sleeve,
and at least one component interfacing at least a portion of the
groove or the protrusion to limit axial movement of the inner
cutting element with respect to the multi-piece split sleeve, in
which the multiple pieces of the split sleeve are joined together
at an overlapping joint, in which the multi-piece sleeve is brazed
into the at least one cutter pocket.
[0089] Referring back to FIG. 2, the inner cutting element 200 may
be a rotatable cutting element that may be rotatable within the
multi-piece split sleeve 210. The inner cutting element 200 may be
disposed within the multi-piece split sleeve 210, which may be
disposed in a cutter pocket formed on at least one blade on a tool
body. As discussed above, the sleeve 210 may include at least one
overlapping joint 212 formed at any point where any pieces of the
split sleeve 210 are joined together or engaged. The multi-piece
sleeve may be brazed into the at least one cutter pocket. As
discussed above, an overlapping joint (e.g., the overlapping joint
212) may be sufficient to resist capillary flow of braze material
between the pieces of the split sleeve 210.
[0090] In one or more embodiments, a cutting tool may include a
tool body, a plurality of blades extending from the tool body, at
least one rotatable cutting element disposed on at least one blade,
in which the rotatable cutting element has a groove formed in a
side surface thereof, and at least one retention element
interfacing the rotatable cutting element at the groove and
limiting axial movement of the rotatable cutting element, in which
the rotatable cutting element includes a smooth and curved
transition between the groove and the neighboring side surface. In
one or more embodiments, the rotating cutting element may include a
smooth and curved transition between the side surface and a bottom
surface of the rotatable cutting element and/or curved side
surfaces and/or bottom surface
[0091] Further, in one or more embodiments, the rotatable cutting
element may be disposed in a sleeve, in which the sleeve may be
brazed into a cutter pocket formed in the at least one blade. In
one or more embodiments, the rotatable cutting element may be
disposed in a cutter pocket without a sleeve. In one or more
embodiments, the sleeve may be a multi-piece sleeve (i.e., the
multi-piece sleeve 210 of FIG. 2), in which the multiple pieces of
the split sleeve are joined together at an overlapping joint (i.e.,
the overlapping joint 212 of FIG. 2).
[0092] According to some embodiments, a multi-piece sleeve or a
combination of the sleeve and cutter pocket may extend greater than
180 degrees around the circumference of the inner cutting element
to radially retain in the inner cutting element within the cutter
pocket. For example, a cutter assembly may include a multi-piece
sleeve and an inner cutting element having a groove or protrusion
formed in a circumferential side surface thereof and disposed in
the sleeve. At least one component may interface at least a portion
of the groove or the protrusion to limit axial movement of the
inner cutting element with respect to the multi-piece sleeve, while
the multi-piece sleeve or a combination of the sleeve and cutter
pocket may extend greater than 180 degrees around the circumference
of the inner cutting element to radially retain in the inner
cutting element within the cutter pocket.
[0093] For example, FIGS. 9-11 show a cutter assembly that has an
inner cutting element retained within a cutter pocket using a
combination of a sleeve and the cutter pocket inner side surface to
extend around greater than 180 degrees of the outer circumferential
side surface of the inner cutting element. As shown in FIGS. 9-11,
a segment of a bit blade 2000 has an inner cutting element 2020
assembled within a cutter pocket 2010. Particularly, the inner
cutting element 2020 has a cutting face 2022, an outer
circumferential surface 2024, and a circumferential channel or
groove 2026 formed within the outer circumferential surface 2024.
The cutter pocket 2010 has a back surface 2012 and an inner side
surface 2014, wherein a receptacle 2015 (represented by the shaded
area) is formed within the side surface 2014 to receive a partial
sleeve 2040. The receptacle 2015 extends from the leading side 2002
of the blade 2000 a distance D along the length of the cutter
pocket 2010 and a radial distance around the side surface of the
cutter pocket 2010. A partial sleeve 2040 may be positioned
adjacent to the inner cutting element 2020, such that the partial
sleeve 2040 extends partially around the outer circumferential
surface 2024 of the inner cutting element 2020. In the embodiment
shown in FIGS. 9-11, the sleeve 2040 is a partial sleeve formed of
a single piece. However, in other embodiments, the sleeve may be a
multi-piece split sleeve, as discussed above. Further, the partial
sleeve 2040 may have a lip or a protrusion 2046 formed thereon that
mates with the circumferential groove 2026 of the inner cutting
element 2020. The inner cutting element 2020 and the partial sleeve
2040 may then be inserted into the cutter pocket 2010. The partial
sleeve 2040 may be attached to the cutter pocket 2010 to form part
of the cutter pocket side surface, wherein the inner cutting
element 2020 may rotate within the cutter pocket 2010 and partial
sleeve 2040. Methods of attaching the partial sleeve 2040 to the
rolling cutter pocket 2010 may include, for example, brazing,
welding, or mechanical locking.
[0094] As shown, the partial sleeve 2040 and the cutter pocket side
surface 2014 may form an arc A. The arc may extend around the inner
cutting element 2020 greater than 180 degrees. Thus, in such
embodiments, the cutter pocket and the partial sleeve may function
similar to the multi-piece split sleeves described above, wherein
the cutter pocket forms one or more pieces surrounding the inner
cutting element and the partial sleeve forms another piece
surrounding the inner cutting element. Advantageously, in some
embodiments having an arc extending greater than 180 degrees, an
inner cutting element may be retained within a cutter pocket using
only the side surface of the cutter pocket and the partial sleeve.
For example, a side surface retention mechanism (the mating
protrusion (or groove) formed along the cutter pocket side
surface/partial sleeve and circumferential groove (or protrusion)
formed within the inner cutting element) may retain the inner
cutting element axially within the cutter pocket and sleeve, while
the extension of the cutter pocket side surface (in combination
with the partial sleeve) greater than 180 degrees may inhibit the
inner cutting element from being dislodged (pulled out from the top
face) from the cutter pocket.
[0095] Further, the shape of a partial sleeve and a corresponding
receptacle may vary. For example, as shown in FIGS. 12 and 13, two
partial sleeves according to embodiments of the present disclosure
are shown. A partial sleeve 2340 has a lower surface 2341 and an
upper surface 2342, wherein the upper surface 2342 is positioned
adjacent to a rolling cutter and forms at least part of the side
surface of a rolling cutter pocket once inserted into a rolling
cutter pocket receptacle. Particularly, the upper surface 2342 of a
partial sleeve 2340 may have an arc shape, which extends around
part of the circumference of a rolling cutter once the partial
sleeve 2340 is assembled with a rolling cutter. Further, as
described above, the upper surface 2342 of a partial sleeve 2340
may have at least one lip 2346 (and/or at least one channel) formed
thereon. The shape of a partial sleeve may be described with
reference to its width W (the distance the partial sleeve extends
from a leading face of a blade into the rolling cutter pocket),
depth D (the distance between the upper surface of the partial
sleeve to the lower surface of the partial sleeve), and arc length
L (the distance around the arc of the upper surface). As shown in
FIG. 12, the depth D of the partial sleeve 2340 may extend a
constant distance from the upper surface 2342 to the lower surface
2341 of the partial sleeve 2340, as measured around the arc length
L. Thus, in such embodiments, the cross-sectional shape along the
length of the partial sleeve 1740 may be an arc, or
partial-circular shape. Alternatively, as shown in FIG. 13, the
depth D of the partial sleeve 2340 may extend a varying distance
from the upper surface 2342 to the lower surface 2341 of the
partial sleeve 2340, as measured around the arc length L. In such
embodiments, the cross-sectional shape along the length of the
partial sleeve may be irregular shapes. Additionally, the width W
of a partial sleeve 2340 may constant or varying, as measured
around the arc length L. One skilled in the art may appreciate that
receptacles according to embodiments of the present disclosure may
have corresponding shapes to the partial sleeve shapes described
above. Particularly, a receptacle may have a negative shape (i.e.,
the shape of the void, or empty space) that mates with a
corresponding partial sleeve.
[0096] In embodiments using a sleeve, such sleeve may be fixed to
the bit body (or other cutting tool) by any means known in the art,
including by casting in place during sintering the bit body (or
other cutting tool) or by brazing the element in place in the
cutter pocket (not shown). Brazing may occur before or after the
inner rotatable cutting element is retained within the sleeve;
however, in particular embodiments, the inner rotatable cutting
element is retained in the sleeve before the sleeve is brazed into
place. Further, in embodiments using a multi-piece sleeve, one or
more pieces of the sleeve may be cast in place during sintering the
bit body and one or more pieces of the sleeve may be fixed to the
bit body by other means, such as brazing. For example, referring
again to FIGS. 9-11, the inner side surface 2014 of the cutter
pocket 2010 may be formed from pieces of a multi-piece sleeve that
are cast in place during sintering of the bit body, while the
partial sleeve 2040 may be another piece of the multi-piece sleeve
that is brazed in place.
[0097] Each of the embodiments described herein have at least one
ultrahard material included therein. Such ultra hard materials may
include a conventional polycrystalline diamond table (a table of
interconnected diamond particles having interstitial spaces
therebetween in which a metal component (such as a metal catalyst)
may reside, a thermally stable diamond layer (i.e., having a
thermal stability greater than that of conventional polycrystalline
diamond, 750.degree. C.) formed, for example, by removing
substantially all metal from the interstitial spaces between
interconnected diamond particles or from a diamond/silicon carbide
composite, or other ultra hard material such as a cubic boron
nitride. Further, in particular embodiments, the inner rotatable
cutting element may be formed entirely of ultrahard material(s),
but the element may include a plurality of diamond grades used, for
example, to form a gradient structure (with a smooth or non-smooth
transition between the grades). In a particular embodiment, a first
diamond grade having smaller particle sizes and/or a higher diamond
density may be used to form the upper portion of the inner
rotatable cutting element (that forms the cutting edge when
installed on a bit or other tool), while a second diamond grade
having larger particle sizes and/or a higher metal content may be
used to form the lower, non-cutting portion of the cutting element.
Further, it is also within the scope of the present disclosure that
more than two diamond grades may be used.
[0098] As known in the art, thermally stable diamond may be formed
in various manners. A typical polycrystalline diamond layer
includes individual diamond "crystals" that are interconnected. The
individual diamond crystals thus form a lattice structure. A metal
catalyst, such as cobalt, may be used to promote recrystallization
of the diamond particles and formation of the lattice structure.
Thus, cobalt particles are typically found within the interstitial
spaces in the diamond lattice structure. Cobalt has a significantly
different coefficient of thermal expansion as compared to diamond.
Therefore, upon heating of a diamond table, the cobalt and the
diamond lattice will expand at different rates, causing cracks to
form in the lattice structure and resulting in deterioration of the
diamond table.
[0099] To obviate this problem, strong acids may be used to "leach"
the cobalt from a polycrystalline diamond lattice structure (either
a thin volume or entire tablet) to at least reduce the damage
experienced from heating diamond-cobalt composite at different
rates upon heating. Examples of "leaching" processes can be found,
for example, in U.S. Pat. Nos. 4,288,248 and 4,104,344. Briefly, a
strong acid, typically hydrofluoric acid or combinations of several
strong acids may be used to treat the diamond table, removing at
least a portion of the co-catalyst from the PDC composite. Suitable
acids include nitric acid, hydrofluoric acid, hydrochloric acid,
sulfuric acid, phosphoric acid, or perchloric acid, or combinations
of these acids. In addition, caustics, such as sodium hydroxide and
potassium hydroxide, have been used to the carbide industry to
digest metallic elements from carbide composites. In addition,
other acidic and basic leaching agents may be used as desired.
Those having ordinary skill in the art will appreciate that the
molarity of the leaching agent may be adjusted depending on the
time desired to leach, concerns about hazards, etc.
[0100] By leaching out the cobalt, thermally stable polycrystalline
(TSP) diamond may be formed. In certain embodiments, only a select
portion of a diamond composite is leached, in order to gain thermal
stability without losing impact resistance. As used herein, the
term TSP includes both of the above (i.e., partially and completely
leached) compounds. Interstitial volumes remaining after leaching
may be reduced by either furthering consolidation or by filling the
volume with a secondary material, such by processes known in the
art and described in U.S. Pat. No. 5,127,923, which is herein
incorporated by reference in its entirety.
[0101] Alternatively, TSP may be formed by forming the diamond
layer in a press using a binder other than cobalt, one such as
silicon, which has a coefficient of thermal expansion more similar
to that of diamond than cobalt has. During the manufacturing
process, a large portion, 80 to 100 volume percent, of the silicon
reacts with the diamond lattice to form silicon carbide which also
has a thermal expansion similar to diamond. Upon heating, any
remaining silicon, silicon carbide, and the diamond lattice will
expand at more similar rates as compared to rates of expansion for
cobalt and diamond, resulting in a more thermally stable layer. PDC
cutters having a TSP cutting layer have relatively low wear rates,
even as cutter temperatures reach 1200.degree. C. However, one of
ordinary skill in the art would recognize that a thermally stable
diamond layer may be formed by other methods known in the art,
including, for example, by altering processing conditions in the
formation of the diamond layer.
[0102] The substrate on which the cutting face is optionally
disposed may be formed of a variety of hard or ultra hard
particles. In one embodiment, the substrate may be formed from a
suitable material such as tungsten carbide, tantalum carbide, or
titanium carbide. Additionally, various binding metals may be
included in the substrate, such as cobalt, nickel, iron, metal
alloys, or mixtures thereof. In the substrate, the metal carbide
grains are supported within the metallic binder, such as cobalt.
Additionally, the substrate may be formed of a sintered tungsten
carbide composite structure. It is well known that various metal
carbide compositions and binders may be used, in addition to
tungsten carbide and cobalt. Thus, references to the use of
tungsten carbide and cobalt are for illustrative purposes only, and
no limitation on the type substrate or binder used is intended. In
another embodiment, the substrate may also be formed from a diamond
ultra hard material such as polycrystalline diamond and thermally
stable diamond. While the illustrated embodiments show the cutting
face and substrate as two distinct pieces, one of skill in the art
should appreciate that it is within the scope of the present
disclosure the cutting face and substrate are integral, identical
compositions. In such an embodiment, it may be preferable to have a
single diamond composite forming the cutting face and substrate or
distinct layers. Specifically, in embodiments where the cutting
element is a rotatable cutting element, the entire cutting element
may be formed from an ultrahard material, including thermally
stable diamond (formed, for example, by removing metal from the
interstitial regions or by forming a diamond/silicon carbide
composite).
[0103] The sleeve may be formed from a variety of materials. In one
embodiment, the sleeve may be formed of a suitable material such as
tungsten carbide, tantalum carbide, or titanium carbide.
Additionally, various binding metals may be included in the outer
support element, such as cobalt, nickel, iron, metal alloys, or
mixtures thereof, such that the metal carbide grains are supported
within the metallic binder. In a particular embodiment, the outer
support element is a cemented tungsten carbide with a cobalt
content ranging from 6 to 13 percent. It is also within the scope
of the present disclosure that the sleeve and/or substrate may also
include one more lubricious materials, such as diamond to reduce
the coefficient of friction therebetween. The components may be
formed of such materials in their entirely or have portions of the
components including such lubricious materials deposited on the
component, such as by chemical plating, chemical vapor deposition
(CVD) including hollow cathode plasma enhanced CVD, physical vapor
deposition, vacuum deposition, arc processes, or high velocity
sprays). In a particular embodiment, a diamond-like coating may be
deposited through CVD or hallow cathode plasma enhanced CVD, such
as the type of coatings disclosed in US 2010/0108403, which is
assigned to the present assignee and herein incorporated by
reference in its entirety.
[0104] In other embodiments, the sleeve may be formed of alloy
steels, nickel-based alloys, and cobalt-based alloys. One of
ordinary skill in the art would also recognize that cutting element
components may be coated with a hardfacing material for increased
erosion protection. Such coatings may be applied by various
techniques known in the art such as, for example, detonation gun
(d-gun) and spray-and-fuse techniques.
[0105] The cutting elements of the present disclosure may be
incorporated in various types of cutting tools, including for
example, as cutters in fixed cutter bits or hole enlargement tools
such as reamers. Bits having the cutting elements of the present
disclosure may include a single rotatable cutting element with the
remaining cutting elements being conventional cutting elements, all
cutting elements being rotatable, or any combination therebetween
of rotatable and conventional cutting elements.
[0106] In some embodiments, the placement of the cutting elements
on the blade of a fixed cutter bit may be selected such that the
rotatable cutting elements are placed in areas experiencing the
greatest wear. For example, in a particular embodiment, rotatable
cutting elements may be placed on the shoulder or nose area of a
fixed cutter bit. Additionally, one of ordinary skill in the art
would recognize that there exists no limitation on the sizes of the
cutting elements of the present disclosure. For example, in various
embodiments, the cutting elements may be formed in sizes including,
but not limited to, 9 mm, 13 mm, 16 mm, and 19 mm.
[0107] Further, one of ordinary skill in the art would also
appreciate that any of the design modifications as described above,
including, for example, side rake, back rake, variations in
geometry, surface alteration/etching, seals, bearings, material
compositions, etc, may be included in various combinations not
limited to those described above in the cutting elements of the
present disclosure. In one embodiment, a cutter may have a side
rake ranging from 0 to .+-.45 degrees. In another embodiment, a
cutter may have a back rake ranging from about 5 to 35 degrees.
[0108] A cutter may be positioned on a blade with a selected back
rake to assist in removing drill cuttings and increasing rate of
penetration. A cutter disposed on a drill bit with side rake may be
forced forward in a radial and tangential direction when the bit
rotates. In some embodiments because the radial direction may
assist the movement of inner rotatable cutting element relative to
outer support element, such rotation my allow greater drill
cuttings removal and provide an improved rate of penetration. One
of ordinary skill in the art will realize that any back rake and
side rake combination may be used with the cutting elements of the
present disclosure to enhance rotatability and/or improve drilling
efficiency.
[0109] As a cutting element contacts formation, the rotating motion
of the cutting element may be continuous or discontinuous. For
example, when the cutting element is mounted with a determined side
rake and/or back rake, the cutting force may be generally pointed
in one direction. Providing a directional cutting force may allow
the cutting element to have a continuous rotating motion, further
enhancing drilling efficiency.
[0110] Embodiments of the present disclosure may provide at least
one of the following advantages. The use of an inner cutting
element with a curved or convex bottom surface may minimize the
contact area between the bottom surface of the inner cutting
element and the sleeve. Because the contact area between the bottom
surface of the inner cutting element and the sleeve may be
minimized, friction may be reduced between the bottom surface of
the inner cutting element and the sleeve may be minimized, which
may extend the life of the inner cutting element. Further, the use
of a multi-piece split sleeve may allow side retention of an inner
cutting element within a cutting assembly without obstructing any
portion of the cutting surface on top of the inner cutting element.
Further, the use of a multi-piece split sleeve having one or more
overlap joints located where any pieces of the split sleeve are
joined together or engaged may allow for the side retention of the
inner cutting element discussed above, while also sufficiently to
resisting capillary flow of braze material between the pieces of
the split sleeve.
[0111] Although only a few example embodiments have been described
in detail above, those skilled in the art will readily appreciate
that many modifications are possible in the example embodiments
without materially departing from this invention. Accordingly, all
such modifications are intended to be included within the scope of
this disclosure as defined in the following claims. In the claims,
means-plus-function clauses are intended to cover the structures
described herein as performing the recited function and not only
structural equivalents, but also equivalent structures. Thus,
although a nail and a screw may not be structural equivalents in
that a nail employs a cylindrical surface to secure wooden parts
together, whereas a screw employs a helical surface, in the
environment of fastening wooden parts, a nail and a screw may be
equivalent structures. It is the express intention of the applicant
not to invoke 35 U.S.C. .sctn.112, paragraph 6 for any limitations
of any of the claims herein, except for those in which the claim
expressly uses the words `means for` together with an associated
function.
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