U.S. patent application number 10/570320 was filed with the patent office on 2008-08-28 for rotary roller reamer.
This patent application is currently assigned to GEARHART UNITED PTY LTD.. Invention is credited to Terry Michael McManus.
Application Number | 20080202818 10/570320 |
Document ID | / |
Family ID | 34230066 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080202818 |
Kind Code |
A1 |
McManus; Terry Michael |
August 28, 2008 |
Rotary Roller Reamer
Abstract
A bore hole rotary reamer (1) includes a body (2) having cutters
(4) contained in respective recesses (3) formed in the body (2).
Each cutter (4) is rotatably mounted by one or more respective
spindles (5). A bearing region (10) is formed by an inner bearing
surface (11) rotatable on an outer surface of the spindle (5). At
least one annular seal (12) about the spindle (5) prevents ingress
of contaminant to the bearing region (b 10). A circumferential void
(13) is formed between the inner bearing surface (11) and the outer
bearing surface of the spindle (5) adjacent the seal (12). At least
one passageway (17) extends in an axial direction of the spindle
(5) to the circumferential void (13) and a piston (19) movable in
the passageway (17) in response to supply of pressure to an outer
side (19a) of the piston (19) from the environment which surrounds
the reamer (1). The piston (19) transfers pressure to fluid in the
cylindrical passage (17) on an inner side of the piston (19) to
supply pressure to the circumferential void (13) and thereby to the
seal (12) that is substantially determined by the pressure of the
environment surrounding the reamer (1).
Inventors: |
McManus; Terry Michael;
(South Australia, AU) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW, SUITE 900
WASHINGTON
DC
20004-2128
US
|
Assignee: |
GEARHART UNITED PTY LTD.
Wingfield, South Australla
AU
|
Family ID: |
34230066 |
Appl. No.: |
10/570320 |
Filed: |
September 3, 2004 |
PCT Filed: |
September 3, 2004 |
PCT NO: |
PCT/AU2004/001198 |
371 Date: |
May 13, 2008 |
Current U.S.
Class: |
175/393 |
Current CPC
Class: |
E21B 10/30 20130101;
E21B 10/24 20130101 |
Class at
Publication: |
175/393 |
International
Class: |
E21B 10/23 20060101
E21B010/23 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2003 |
AU |
2003904796 |
Claims
1. A bore hole rotary reamer comprising a body having cutters
contained in respective recesses formed in the body, each cutter
being rotatably mounted by one or more respective spindles and a
bearing region formed by an inner bearing surface rotatable on an
outer surface of the spindle; at least one annular seal about the
spindle to prevent ingress of contaminant to the bearing region; a
circumferential void formed between the inner bearing surface and
the outer bearing surface of the spindle adjacent said seal; at
least one passageway extending in an axial direction of the spindle
to said circumferential void; and a piston movable in said
passageway in response to supply of pressure to an outer side of
said piston from the environment which surrounds the reamer,
whereby the piston transfers pressure to fluid in said cylindrical
passage on an inner side of said piston to supply pressure to said
circumferential void and thereby to said seal that is substantially
determined by the pressure of the environment surrounding the
reamer.
2. A bore hole rotary reamer according to claim 1, wherein the
pressure that is applied to said seals via said apertures is
substantially the pressure of the environment surrounding the
reamer.
3. A bore hole rotary reamer according to claim 1, wherein said
piston is freely floatable in said passageway to impart the
pressure supplied from the environment which surrounds the reamer
to fluid on said inner side of the piston.
4. A bore hole rotary reamer according to claim 1, wherein, in use,
the fluid on said inner side of said piston is a lubricant and said
piston impels a flow of lubricant to said circumferential void to
apply pressure to said seal.
5. A bore hole rotary reamer according to claim 1, wherein said
passageway includes a cylindrical portion extending axially of the
spindle containing said piston and an aperture communicating
between said cylindrical portion and said circumferential void.
6. A bore hole rotary reamer according to claim 1, comprising an
annular seal at each end of said bearing region each annular seal
having an adjacent circumferential void and one or more of said
passageway extending to each circumferential void.
7. A bore hole rotary reamer according to claim 6, wherein a
separate passageway respectively extends to each of said
circumferential voids and each passageway includes one said movable
piston.
8. A bore hole rotary reamer according to claim 6, wherein each
cutter is rotatably mounted on a central region of a respective
spindle and said bearing region is formed by an inner surface of
the cutter rotatable on an outer surface of the spindle.
9. A bore hole rotary reamer according to claim 8, wherein a
separate passageway respectively extends between each of said
circumferential voids and a corresponding cuter end of the
respective spindle.
10. A bore hole rotary reamer according to claim 1, wherein said
circumferential voids are formed by grooves on the outer surface of
the spindle.
11. A bore hole rotary reamer according to claim 1, wherein said
circumferential voids are formed by grooves in said inner bearing
surface.
12. A bore hole rotary reamer comprising a body having cutters
contained in respective recesses formed in the body, each cutter
being rotatably mounted in a central region of a respective spindle
and having a bearing region formed by an inner bearing surface of
the cutter rotatable on an outer surface of the spindle; annular
seals interposed between the cutter and spindle at each end of the
bearing region to prevent ingress of contaminant; a circumferential
void formed between the inner bearing surface and the outer bearing
surface of the spindle at each end of the bearing region adjacent
each said seal, at least one cylindrical passage extending in an
axial direction in each spindle, respective apertures extending
from said cylindrical passage to each of said circumferential
voids; and a piston freely floatable in said cylindrical passage
between an outer end of said cylindrical passage and said
apertures, an outer end of said piston being supplied with pressure
substantially equal to the pressure of the environment which
surrounds the reamer, whereby the piston imparts that pressure to
lubricant when contained in said cylindrical passage and impels a
flow of said lubricant to said circumferential voids to apply a
lubricant pressure to each of said seals that is substantially the
pressure of the environment surrounding the reamer.
13. (canceled)
Description
FIELD OF THE INVENTION
[0001] This invention relates to a bore roller hole rotary reamer.
Rotary reamers of this type are used for reaming a hole made by a
drill on the end of a drill string. The rotary reamer generally
serves the function of maintaining the hole size when wear causes
the effective diameter of a drill to reduce and also to smooth the
surface of the bore hole.
BACKGROUND
[0002] The general construction of commercially successful roller
rotary reamers are shown in the applicants Australian patents
594885 and 675186.
[0003] Australian patent 675186 describes a rotary roller reamer in
which the pressure of the environment surrounding the reamer is
applied to the lubricant supplied to the roller bearing surface by
means of a freely floating piston contained in a cylindrical
passage. This results in significantly improved lubrication and
reduction of the ingress of contaminant material to the bearing
surface. Whilst the rotary roller reamer described in Australian
patent 675186 has a significantly extended life for the wear
components the present invention seeks to provide a further
improved rotary roller reamer.
[0004] The objective of the pressure equalisation system described
in Australian patent 675186 is to reduce or eliminate the
differential pressure across the sealing device provided between
the roller and spindle on which it is mounted to prevent ingress of
contaminant to the bearing region. The sealing device is often an
O-ring or a more complex seal. In the case of O-rings and most
other types of seal, a reduction of the differential pressure will
reduce the contact pressure between the seal and the sealing
surface. This in turn will assist in reducing wear and subsequent
seal failure.
[0005] In the rotary roller reamer described in Australian patent
675186 the lubricant is supplied to the bearing surface through
apertures from a central passage which supply the lubricant to flat
formed on the spindle that effectively provides a passageway
extending along the bearing. Thus, the lubricant reaches the seals
largely by being transmitted along the bearing surface. It has been
recognised in this configuration the bearing itself acts as a
pressure barrier partly because of the rotation of the roller at
around three times the speed of the drill string. Additionally in
the arrangement described in Australian patent 675186 the thrust
bearing ball race is also interposed between the supply of
lubricant and the seal at one end of the roller. This also acts as
a pressure barrier.
DISCLOSURE OF THE INVENTION
[0006] It is an object of the present invention to provide an
improved rotary roller reamer.
[0007] Accordingly, one aspect of this invention provides a bore
hole rotary reamer comprising a body having cutters contained in
respective recesses formed in the body, each cutter being rotatably
mounted by one or more respective spindles and a bearing region
formed by an inner bearing surface rotatable on an outer surface of
the spindle; at least one annular seal about the spindle to prevent
ingress of contaminant to the bearing region; a circumferential
void formed between the inner bearing surface and the outer bearing
surface of the spindle adjacent said seal; at least one passageway
extending in an axial direction of the spindle to said
circumferential void; and a piston movable in said passageway in
response to supply of pressure to an outer side of said piston from
the environment which surrounds the reamer, whereby the piston
transfers pressure to fluid in said cylindrical passage on an inner
side of said piston to supply pressure to said circumferential void
and thereby to said seal that is substantially determined by the
pressure of the environment surrounding the reamer.
[0008] Preferably the pressure that is applied to the seals via the
apertures is substantially the pressure of the environment
surrounding the reamer. The piston is preferably freely floatable
in the passageway to impart the pressure supplied from the
environment which surrounds the reamer to fluid on the inner side
of the piston.
[0009] In use the fluid on the inner side of the piston is a
lubricant and the piston impels a flow of lubricant to the
circumferential void to apply pressure to the seal. In the
preferred form of the invention the passageway includes a
cylindrical portion extending axially of the spindle that contains
the piston. In this form of the invention an aperture preferably
communicates between the cylindrical portion and the
circumferential void. The aperture is preferably a radially
extending aperture.
[0010] In the preferred form of the invention annular seals are
provided on each of two ends of the bearing region and each annular
seal has an adjacent circumferential void. One or more passageways
preferably extend to each circumferential void. More preferably, a
separate passageway extends to each circumferential void and each
passageway includes a movable piston.
[0011] Each cutter is preferably rotatably mounted on a central
region of a respective spindle and the bearing region is formed by
inner-surface of the cutter rotatable on an outer surface of the
spindle. In this form of the invention a separate passageway
preferably respectively extends between each of the circumferential
voids and a corresponding outer end of the spindle. It will be
apparent that although the preferred form of the invention
described an arrangement in which the cutter is rotatably mounted
on a central portion of the spindle, in other forms of the
invention the cutter can be mounted fixed to a spindle or have
spindle portions extending from each end. In these configurations
the spindles are rotatably mounted in the body so that the bearing
region is formed between an inner surface of the body and the outer
surface of the spindle.
[0012] The circumferential voids are preferably formed by grooves
on the outer surface of the spindle or by grooves on the inner
bearing surface.
[0013] It will be apparent that the use of two freely floating
pistons in the preferred form of the invention respectively in
passageways between the respective one of the voids and the
adjacent outer end of the spindle provides significant advantages
over the prior art. In particular the lubricant in each cylindrical
passage is independently pressurised and caused to flow through the
apertures to the circumferential voids. The use of the two pistons
improves the transmission of the pressure of the environment to the
lubricant and ultimately to the voids adjacent the seals.
[0014] The provision of the circumferential voids adjacent the
seals spaces the seals from the bearing surface. This is thought to
be a further advantage of the invention because the fluid filled
load carrying bearing also generates its own internal pressure to
carry the load. The interposing of the circumferential voids
between the load carrying region and the seals serves to reduce or
eliminate any effect that this pressure has on the pressure applied
to the seal. In some embodiments the void may need to be spaced a
small distance from the seal. In this case additional clearance is
provided between the outer surface of the spindle and inner surface
of the cutter so that there is no bearing between the void and
seal.
[0015] The rotary roller reamer of this invention thus provides
improved equalisation of the pressure across the seals which
extends the seal fife and consequently the life of the wear
components of the reamer.
[0016] Embodiments of the invention will now be described, by way
of example only, with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic cross section of part of a rotary
roller reamer according to a first embodiment of the present
invention including enlarged scrap sections of the indicated
portions; and
[0018] FIG. 2 is a schematic cross section and scrap section
similar to FIG. 1 showing a second embodiment of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0019] The rotary roller reamer 1 of this invention has a number of
components of substantially conventional type as described in
Australian patents 594885 and 675186, the contents of which are
incorporated herein by cross reference.
[0020] As shown in FIG. 1 the rotary roller reamer 1 of the first
embodiment has a body 2 in which recesses 3 (only one is shown) are
formed to receive a roller or cutter 4. As will be appreciated by
those skilled in the art a number of cutters 4 are mounted in
similar recesses around the circumference of the reamer body 2. The
cutter 4 is rotatably mounted in a central region of spindle 5.
Spindle 5 is retained in the body 2 by top block 6 and bottom block
7. Blocks 6 and 7 are retained in the body 2 using the wedge system
(not shown) described in the applicant's Australian patents 594885
and 675186. The spindle 5 is retained by in interference fit in the
top 6 and in the bottom block by grub screw 8. Both the cutters 4
and blocks 6, 7 have a number of tungsten carbide inserts 9 of
conventional type to reduce wear.
[0021] A bearing region 10 is formed by an inner bearing surface 11
of cutter 4 that is rotatable on an outer surface of the spindle.
Annular seals 12 are interposed between the cutter 4 and spindle 5
at each end of the bearing region 10. The seals 12 are a lip type
and prevent ingress of contaminant into the bearing region 10.
Circumferential voids 13 are formed adjacent each seal 12. Each
void is partly formed by a circumferential groove 14 in the spindle
5 and a circumferential groove 15 adjacent the seal formed in the
inner surface 11 of cutter 4. A conventional thrust race 16 of
steel bearings to absorb longitudinal forces is provided toward one
end of the cutter 4. Cylindrical passageways 17 extends axially
from each outer end of the spindle 5. Two smaller passageway
portions 17a connect to piston apertures 18 to provide
communication between the cylindrical passageway 17 and the
circumferential voids 13. Freely floating pistons 19 are provided
in each of the passageways 17. Removable annular bungs 20 at the
end of each passageway 17 are provided for removal of the piston
and charging of the cylindrical passageway 17 with lubricant such
as grease. Annular bungs 20 have a central hole 21 which provides
communication via a breather aperture 22 to the environment around
the reamer body 2. A flat 23 is formed on the outer surface between
apertures 18 to provide a passageway for the flow of lubricant
along the spindle 5. The passageway can be formed by another shape
or groove to give a larger cross sectional area.
[0022] It will be apparent that the freely floating pistons 19 are
provided on their outer ends 19a with a pressure substantially
equal to the pressure of the environment surrounding the reamer
body 2. The freely floating pistons 19 transmit this pressure to
the lubricant contained in cylindrical passageway 17. This causes
the lubricant to be forced through apertures 18 into voids 13 and
along flat 23 to lubricate the bearing region 10. The lubricant
forced into void 13 applies a pressure to the respective adjacent
seal 12 that is substantially equal to the pressure surrounding the
reamer body 2.
[0023] By providing a more effective communication of the pressure
surrounding the reamer to the interior of the seals the pressure
differential across the seal is minimised. As a result the seal
life is considerably extended and consequently the life of the
bearings considerably extended. Additionally it will be appreciated
that the voids 13 provide a spacing between the effective bearing
surface of the cutter 4 and the seals. This spacing, and the
transmission of the external pressure to those voids reduces or
eliminates the transmission of the pressure generated by the
rotation of the bearing itself to the seals 12.
[0024] FIG. 2 shows a rotary roller reamer 1 according to a second
embodiment. Most of the components are common with the first
embodiment and the same reference numerals have been used in the
second embodiment voids 13 are formed on annular grooves in the
inner surface 11 of cutter 4. The seal 12 is formed by an O-ring
12A and packing 12B. A clearance is provided between cutter 4 and
inner surface 11 of cutter 4 in the region between seal 12 and void
13 to prevent the generation of pressure by rotation of the cutter.
In all other respects the rotary reamer shown in FIG. 2 operates in
the manner described above for the FIG. 1 embodiment.
[0025] Throughout this specification and the claims which follow,
unless the context requires otherwise, the word "comprise", and
variations such as "comprises" and "comprising", will be understood
to imply the inclusion of a stated integer or step or group of
integers or steps but not the exclusion of any other integer or
step or group of integers or steps.
[0026] The reference to any prior art in this specification is not,
and should not be taken as, an acknowledgement or any form of
suggestion that that prior art forms part of the common general
knowledge in Australia.
[0027] The foregoing describes only one embodiment of the present
invention and modifications can be made without departing from the
scope of the invention.
* * * * *