Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
S1~9
INTERMITTENTLY ROTATABLE DOWN HOLE DRILI,ING TOOL
THRUST BEARING FOR USE THEREIN AND METHOD OF
ASS~MBLY OF SUCH THRUST BEARING
Back round of the Invention
g _ _
This invention in accordance with one aspect thereof is
eoncerned with drilling tools of the type which may be used
for drilling oil and gas wells to a great depth in the
earth's crust.
It is eommon praetice to provide such a drilling tool in
which the drill bit which is disposea at the lower end of the
tool is operatively rotated, during which fluid commonly
referred to as drilling mud is pumped throu~h the drill
string and the associated heavy drill eollars to flushing
ducting in the drill bit from whieh the drilling mud exits
in the form of a pressurised jet or jets, this jet or jets
of drilling mud serving to clean the bottom of the bore hole
being cut by the drill bit with the cuttings and ehips formed
by the drill bit being carried upwardly by the drilling mud
along an annular space between the drill string and the wall
oE the bore hole ~ormed by the drill bit to the surface at
which the drilling mud may be cleaned and reused.
. As will be appreciated, the torque required to rotate the long
drill string is very considerable in view of the weight of the
drill collars disposed above the drill bit and, more particu-
larly, in view of the frictional resistance which requires to
be overcome, the drill string in view of its very considerable
length seldom being truly straight so that this frictional
s~
resistance is thereby increased. With the view to eliminating
or at least minimizing these disadvantages it has hitherto
been known to provide a down hole motox for operatively driving
the drill bit and which is disposed at the lower end portion
of the drill string and above the d~ill bit, or to provide
a hammer or percussive motor by which a hammer or percussive
effect is operatively applied to the drill bit.
A number of designs of such down hole motor and percussive
or hammer motor devices have been developed, one of the most
widely used designs which utilizes a positive displacement
motor being that marketed under the trademark Dynadrill, but
certain disadvantages inherent to this design such as, for
example, the relatively low torque available from the motor
and its relatively short operating life together with the fact
that a principal component of the motor is constructed frorn
- an elastomer which precludes use of the motor in thermal bore
holes have restricted the use of this design of device to
cases where higher costs and shorter operational life are
acceptable.
In alternative designs of down hole motors the motors are
constituted by axial flow turbines, but these forms of motors
which are known as turbodrills require that at the surface the
fluid for operation of the turbines be at an extremely high
pressure and high volume fluid flows are required. Further-
more, such motors are also very expensive to manufacture andmaintain, and since low torque but high rotational speed are
characteristics of these turbodrills the use of such down hole
motors which have mainly been restricted to cases where the
drill bits are diamond tipped is not ideal where the motors
operatively drive core rock bits.
In all the above-described prior forms of down hole motors
the drill bits are operatively continuously rotated so that
in these down hole motors, and also in percussive or hammer
devices whcre the drill bits are operatively continuously
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Z~56~
rotated from the surface by the drill string, there are still
substantial associated frictional forces and there is an
inevitable reduction in the pressure of the drilling mud 1
leaving from t~e drïll bits because of the work required to
be performed by the drilling mud in rotating the drill bits,
or in actuating the percussive or hammer motors. The cleaning
action of the jet or jets on t~e bottom of the bore hole being
formed by the drill bit is thus correspondingly reduced.
Furthermore, the continuous operative rotation of the drill
bit impedes the drilling mud jet or jets from the drill bit
so that turbulence is created with resultant loss in the
pressure and energy of t~e drilling mud jet or jets and hence
with a resultant reduction in the cleaning action on the bottom
of the bore hole, this turbulence being further increased if
the drill bit incorporates toothed cones which also rotate
during operative rotation of the drill bit. Thus, cuttings
and chips tend to remain on the bottom of the ~ore hole and
act as a cushion against which the drill bit operates thereby
significantly reducing the rate of drilling.
In the hitherto known forms of percussive or hammer devices
the member which provides the percussive or hammer effect is
spaced from the drill bit, or from a member on which the drill
bit is directly or indirectly mounted, except at the moment of
impact during each cycle of operation of the device, and in
use such percussive or hammer devices can result in breakage
of the drill bit or other damage to the device.
A ~urther aspect of the present invention is concerned with
axial thrust bearings which may be used in down hole drilling
tools in accordance with said one aspect of the present
invPntion but which may also be used in other f~rms of
apparatus particularly where high axial thrust forces are
involved, and a still further aspect of the present invention
is concerned with the provision of a method of assembly of
such an axial thrust bearing.
~L2~5~i~
Summary of the Invention
It is a primary object of said one aspect of the present
invention to provide a down hole drilling tool which is of
improved form in that the above-described disadvantages of
the hitherto known forms of down hole motors and percussive
or hammer devices are substantially o~tviated or mitigated,
since the above-mentioned tur~ulence in the drilling mud jet
or jets with the drill bit tending to operate on a cushion
of cuttings or chips at the bottom of the bore hole is
substantially avoided, and the forces operatively applied
to the drill bit are substantially automatically controlled
thereby to reduce ri~k of breakage of the drill bit or other
damage to the tool.
A down hole drilling tool in accordance with this one aspect
of the present invention comprises an elongated hollow housing
having a longitudinal axis and having an upper end and a lower
end, and a fluid control valve which is mounted within the
housing for axial movement between an upper position and a
lower position. The fluid control valve comprises a first
valve member and a second valve member movable relative to
the first valve member between a closed condition of the
valve in which the valve substantially pxevents downward flow
of pressurised fluid through the housing and an open condition
of the valve in which downward flow of pressurised ~luid is
~5 permitted through the valve, the valve being upwardly urged.
The valve presents valve actuation means which on operative
downward movement of the valve under the influence of
pressurised fluid thereabove and against the influence of the
upward urging of the valve and during which the valve is in
its closed condition causes actuation of the valve to its
open condition when the valve attains its lower position. On
operative upward movement of the valve under the influence of
the upward urging of the valve and during which the valve is
in its open condition the valve actuation means causes
actuation of the valve to its closed condition when the valve
attains its upper position. A torque member is rotatably
t
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mounted within the housing and is continuously coupled to the
first valve member. Helically disposed first coupling means
and second coupling means engaged with the first coupling
means axe provided for operative rotation of the torque member
in one direction during downward movement of the first valve
member and operative rotation of the torque member in the
opposite direction during upward movement of the first valve
member. A drill bit is rotatably mounted on and projects
downwardly from the lower end of the housingl and a one-way
clutch interconnects the torque member and the drill bit for
drivingly coupling the torque member to the drill bit only
during operative rotation of the torque member in said one
direction whereby the drill bit is operatively intermittently
rotated. Fluid flushing ducting is provided in the drill bit,
and fluid flow passage means interconnects the valve with the
fluid flushing ducting for operative flow of pressurised fluid
through the valve, the fluid flow passage means and the fluid
flushing ducting in the drill bit only while the torque member
is operatively rotating in said opposite direction during which
the valve is in its open condition and the drill bit is non-
rotating.
It is a primary object of said further aspect of the present
invention to provide an axial thrust bearing which is of simple
form and may be easily and inexpensively manufactured and which
can accommodate extremely high axial thrust forces.
According to this further aspect of the present invention there
is provided an axial thrust bearing for use in a down hole
drilling tool, the axial thrust bearing comprising a cylindrical
tubular housing member having an inner face, a cylindrical rotor
member disposed within said housing member and having an outer
face adjacent the inner face of said housing member, at least
one annular groove in the inner face of said housing member, an
annular groove in the outer face of said rotor member in align-
ment with said groove in said housing member, said aligned
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grooves together constituting a ball bearing track, a plurality
of freely movable ball bearings disposed in the ball bearing
track partially in each of said grooves whereby downward axial
thrust on said housing member may be transmitted through the
ball bearings to said rotor member, an annular pocket provided
in one of said faces of said members and having one side and
an opposed side, said one side of said pocket being in commu-
nication with the annular groove in said one of said faces of
said members, and an annular lip bounding said opposed side of
the pocket at said one of said faces of said members for
retaining the ball bearings wholly within -the pocket when,
during assembly and disassembly of said members, the members
are disposed with the annular lip up~ardly directed and the
members are axially relatively moved.
In accordance with said still further aspect of the present
invention there is provided a method of assembly of an axial
thrust bearing according to said further aspect of the invention.
Thus, in accordance with said still further aspect of the inven-
tion there is provided a method of assembly of an axial thrust
bearing which is for use in a down hole drilling tool and which
comprises a cylindrical tubular housing member having an inner
face, a cylindrical rotor member disposed within said housing
member and having an outer face adjacent the inner face of said
housing member, at least one annular groove in the inner face
o said housing member, an annular groove in the outer face of
said rotor member in alignment with said groo~e in said housing
member, said aligned grooves together constituting a ball
bearing track, a plurality of freely movable ball bearings
disposed in the ball bearing track partially in each of said
grooves constituting the ball bearing track, and an annular
lipped pocket provided in one of said faces of said members in
communication with the annular groove therein, the method
comprising the steps of assembling the thrust bearing by
disposing the plurality of ball bearings in the annular pocket
35 ~ with the lip thereon upwardly directed to retain the ball
bearings therein, relatively axially moving said members to
2~
- 6a -
- bring the annular pocket into alignment with the groove in
the other of said members, and inverting said members and
further relatively axially moving said members to align the
grooves in said members, with the plurali~y of ball bearings
being transferred from the annular pocket to be disposed
partially in each groove of the aligned grooves.
Brie~ Description of the Drawings
In order that the invention may be more clearly understood
and more readily carried into effect the same will now, by
way of example, be more fully described with reference to
the accompanying drawings in which:
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5~
Fig. 1 is a view of well drilling tool according to a preferred
embodiment of said one aspect of the present invention, and
incorporating an axial thrust bearing according to a preferred
embodiment of said further aspect of the invention;
Figs. 2, 3, 4, 5 and 6 together show on an enlarged scale the
well drilling tool of Fig. 1, and the axial thrust bearing
incorporated therein, in longitudinal axial section on one
side of a longitudinal axis thereof, with the left-hand end
of Fig. 3 being a continuation from the right-hand end of
Fig. 2, the left-hand end of Fig. 4 being a continuation from
the right-hand end of Fig. 3, the left-hand end of Fig. 5
being a continuation from the right-hand end of Fig. 4, and
the left-hand end of Fig. 6 being a continuation from the
right-hand end of Fig. 5;
Fig. 7 is a sectioned view on the line 7-7 in Fig. 4;
Fig. 8 is a sectioned view on the line 8~8 in Fig. 5;
Fig. 9 is a view of a portion of the tool shown in the preceding
views;
Figs. 10 and 11 are views corresponding to Figs. 2 and 3,
respectively, but showing the tool in a different operative
condition;
Fig. 12 is a view substantially corresponding to Fig. 4, but
showing a portion of a tool according to a modified form sf
the preferred embodiment of the invention;
Fig. 13 is a sectioned view on the line 13-13 in Fig. 12;
Fig. 14 is a view of part of the portion of the tool shown
in Fig. 12 in the direction of the arrow 14 in Fig. 12;
Fig. 15 is a view generally corresponding to Fig. 4 but showing
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a portion of a tool according to a further modified form of
- the preferred embodiment of the invention;
Fiy. 16 is a sect;on view on the line 16 16 in Fig. 15;
Fig. 17 is a view generally corresponding to part of Fig. 5
but on a further enlarged scale and showing the tool only to
one side of the longitud;nal axis, this view illustrating a
further modified form of the preferred embodiment of the
invention;
Fig~ 18 is a view substantially corresponding to Fig. 17, but
showing the portion in question of the tool according to a
still further modifîed form of the preferred embodiment of
the invention;
Fig. 19 is a sectioned view on the line 19-19 in Fig. 18;
Figs,20 and 21 are views in the direction of the section line
19-19 in Fig. 18 of parts illustrated therein;
Figs.22-and 23 together show a portion of a well drilling
tool according to a further preferred embodiment of said one
aspect of the invention, these views showing the tool in
longitudinal axial section on one side of a longitudinal
axis thereof, with the left-hand end of Fig. 23 being a
continuation from the right-hand end of Fig. 22;
Fig. 24 is a sectioned view on the line 24-24 in Fig. 23;
Fig. 25 is a sectioned view on the line 25-25 in Fig. 23;
Fig. 26 is a view generally corresponding to Fig. 23, but
showing the tool in a different operative condition; and
Fig. 27 is a view corresponding to Fig. 22, but showing a
portion of a tool according to a modified form of said
further preferred embodiment of the invention.
~2~
Descxiption of the Preferred Embodiments
Refexring to the drawings and in particular to Figs. 1 to
11, inclusive, 10 denotes genPrally an elongated hollow
housing which comprises a plurality of pipe sections or subs
lOA through lOF, inclusive, disposed at the lower end of a
drill string 11 (Fig. 1), the subs lOA to lOE, inclusive,
being interconnected by tapered screw-th~eading 12 as is
conventional in the art. The section lOF is connected to
the section lOE by axial screw threading 13. The housing 10
has a substantially vertical longitudinal axis 14, with the
end 15 of the housing 10, i.e. the left-hand end of the sub
lOA as viewed in Fig. 2 operatively constituting the upper end
of the housing 10 and the end 16 of the housing 10, i.e. the
right-hand end of the pipe section lOF as viewed in Fig.
operatively constituting the lower end of the housing 10.
- Mounted within the housing 10 is a fluid control valve denoted
generally by the reference numeral 17 and comprising in the
preferred embodiment shown in Figs. 1 to 21, inclusive, a spool
valve incorporating a first valve member 18 which includes an
inner cylindrical member 19, and a second valve member 20 which
includes an outer cylindrical member 21 coaxially slidably
mounted on the inner cylindrical member 19, rows-of angularly
spaced fluid flow openings 22 being provided in the inner
cylindrical member 19, and corresponding rows of angularly
spaced fluid flow openings 23 being provided in the outer
cylindrical member 21, so that on relative axial movement
between the first and second valve members 18, 20 as herein-
after more fully described the rows of apertures 22, 23 may
be brought into overlapping relationship (Fig. 11) in which the
valve 17 is in an open condition thereof, and into non-
overlapping relationship (Fig. 3) in which the valve 17 is in
a closed condition thereof. As will be appreciated there
could, of course, be only one row of openings with only one
corresponding row of openings 23, or merely one opening 22
with one corresponding opening 23~ Spaced piston rings 24
are mounted on the inner cylindrical member 19 in sealing
~2~
contact with the outer cylindrical member 21, and further
spaced piston rings 25, together with spaced wear rings 26
are mounted on the inner cylindrical member 19 in sealing
contact with the sub lOB.
,
At its upper end portion the outer cylindrical member 21 has
an inwardly directed annular shoulder 27 and a short cylind-
rical portion 28 which is secured by means of angularly
spaced pins 29 to a cylindrical sleeve 30. This sleeve 30
is axially slidably mounted on a shaft 31, the upper end
portion of which is screw threadedly connected to the lower
end of a further shaft 32. Screw threadedly mounted on the
upper end of the sleeve 30 is a collar 33 on which is mounted
a wiper ring 34 and an O-ring seal 35 bearing on the shaft 31.
A bracket 36 comprising a flange 37 and a short cylindrical
portion 38 which is in abutting contact with a shoulder 39
presented by the sub lOA is slidably mounted on the shaft 32
with a compression coil spring 40 surrounding the shaft 32 and
acting between the bracket 36 and a spring support member 41
mounted on the upper end portion of the shaft 32. This
mounting of the member 41 on the shaft 32 comprises an annular
groove 42 provided in the upper end portion of the shaft 32 and
an aligned annular groove 43 provided in a skirt portion 44 of
the member 41, a plurality of ball bearings 45 each being
disposed partially within the groove 42 and partially within
~5 the groove 43. The spring support member 41 is also provided
with an annular pocket 46 which is disposed above and in commu-
nication with the groove 43, this pocket 46 having a radial
width sufficient to accommodate the plurality of ball
bearings 45 when, during assembly of the member 41 on the
shàft 32, the shaft 32 is initially disposed through the
member 41. The bottom of the annular pocket 46 is inwardly
and downwardly inclined so that when the member 41 is urged
downwardly against the influence of the spring 40 the ball
bearings 45 descend downwardly and inwardly across this
inclined bottom of the pocket 46 to be partially disposed
~2~5~
in the groove 42. The member 41 is then released whereupon
under the influence of the spring 40 the member 41 moves
axially upwardly relative to the shaft 32 partially to
dispose the ball bearings 45 in the groove 42 and partially
in the groove 43. With the ball bearings 45 so disposed (as
shown in Fig. 2) ~he ball bearings 45 serve to prevent further
upward movement of the member 41 relative to the shaft 32
and thereby secure the spring 40 about the shaft 32. In
order to disassemble the spxing 40 rom the shaft 32 the
above-described operations are performed in reverse and in
the reverse sequence, and as will be appreciated this assembly ~
~ provides a simple and convenient arrangement for assembly and
disassembly of the spring 4Q on the shaft 32~ ~ fluid flow
openiny or openings 47 are provided in the skirt portion 44 ~
and a guide flange portion 4S of the member 41 and in the
flange 37 of the bracket for a purpose which is hereinafter
explained.
Presented by the second valve member 20 is an abutment means
49 which in the preferred embodiment of Figs. 1 to 21,
: 20 inclusive, comprises an inner flange portion 50 t an outer
flange portion 51 and an intermediate cylindrical portion 52,
a fluid flow opening or preferably angularly spaced fluid
flow openings 53 being provided in the inner flange portion 50
and in the cylindrical portion 52. The abutment means 49 is
preferably slidably mounted on the sleeve 30 between two
springs 54, 55 which may be of the Belleville type, the
spring 54 being disposed between one face of the flange portion
50 and the adjacent end of the collar 33, and the spring 55
bein~ disposed between the opposed face of the flange portion
50 and an annular rib 56 presented by the sleeve 30.
The inner cylindrical member 19 is screw threadedly connected
to the shaft 31 and presents a sleeve portion 57 slidably
mounted on the sleeve 30, an O-ring 58 being mounted on the
sleeve 30 in sealing contact with the sleeve portion 57. A
relatively light spring 59 is disposed around the sleeve
`` portion 57 and acts between the shoulder 27 and the inner
- 12 --
6~
cylindrical member 19, with.an opening or openings 60 being
provided in the outer cylindrical member 21 in communication
with the chamber 61 in which the spring 59 is disposed.
Screw threadedly mounted on the lower end portion of the inner
cylindrical mem~er 19 is a cylindrical extension membex 62, a
stud or preferably a plurality of angularly spaced studs 63
being mounted in the member 62 with each stud 63 having an
outwardly projecting end portion on which a roller 64 is
rotatably mounted by means of a ball beaxing race 65. The
lQ rollers 64 are each engaged within an axially disposed groove
66 provided in the inner face o~ the.sub lOC, for p~eventing
rotation of the first valve member 18, the rollers 64 each
being freely rotatable a~out an axis substantially at right
angles to the longitudinal axis of the respective groove 66.
A fuxther stud or prefera~ly a further plurality of angularly
spaced studs 67 are mounted in the member 62 with end portions
of these studs 67 projecting inwardly therefrom and each
having a roller 68 rotatably mounted thereon by means of a
ball bearing race 69, these rollers 68 each being disposed
within a helical groove 70 provided in a hollow tubular torque
member 71, the upper end of which. has screw-threadedly mounted
thereon an end collar 72. The helical grooves 70 thus con-
stitute helically disposed first coupling means with the
rollers 68 constituting second coupling means continuously
engaged with the first coupling means, the rollers 68 each
being freely rotatable about an axis substantially at right
angles to the longitudinal axis of the respective groove 7QO
The lower end portion 73 of the torque member 71 is coaxially
disposed around the upper end portion 74 of a hollow cylind-
rical rotor 75, these end portions 73, 74 constituting elements
of a one-way clutch 76 which may be of conventional form and
which also comprises an intermediate roller cage 77 in which
rollers 78 disposed in tapered slots 79 in the end portion 74
are rotatably mounted. As shown in Fig. 5, a spring 80 is
connected between the cage 77 and a screw 81 which is mounted
in the end portion 74 and which is positioned in a part-
~.;
~ 13 -
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circumferential slot 82 in the cage 77, thereby resiliently
to maintain the clutch 7~ in the condition in which it is
ready for driviny engagement. The torque member 71 is
resiliently urged downwardly by a spring 83 acting on an
annular member 84, a.ball bearing race 85 being disposed
between the member 84 and the torque member 71. A further
ball bearing race 173 is disposed between the upper end of
the upper end portion 74 of the rotor 75 and the adjacent
face of the torque member 71, a sleeve 174 which supports the
ball bearing race 173 being screw-threadedly mounted on the
torque member 71~ Also fluid flow ducting 175 is provided
in the rotor 75 for drainage of any fluid in the space
occupied by the lower end portion 73 of the torgue member
71 into the interior of the rotor 75.
Below the one-way clutch 76` there is incorporated an axial
thrust bearing 86 which comprises a cylindrical tubular
member constituted by the sub.10~ and a cylindrical member
constituted by the rotor 75, a plurality of annular grooves 87
being provided i.n the inner face of the sub lOE, and a corres-
ponding plurality of annular grooves 88 being provided in the
outer face of the rotor 75 with each groove 88 being in align-
ment with one of the grooves 87. Each groove 87 and the aligned
groove 88 together constitute a ball bearing track, a plurality
of freely movable ball bearings 89 being disposed in this ball
bearing track partially in each of the grooves 87, 88, so that
downward axial thrust on the housing 10 is operatively trans-
mitted through thQ thrust bearing 86 to the rotor 75. An
annular pocket 90 is also provided in the rotor 75 above and
. in communication with each annular groove 88, the upper edge
o each pocket 90 being in the form of a downwardly directed
lip 91. It will, of course, be appreciated that there could
be only one groove 87 and one corresponding groove 88, in
which case there would be a single ball bearing track
constituted by the aligned grooves 87, 88, and a single
pocket 90 in communication with the groove 88.
In the assembly of the axial thrust bearing 86 the rotor 75
is lowered while inverted, relative to its orientation when
the -tool is operatively in use, into the sub lOE, the ball
bearings 89 ~eing disposed during this lowering of the rotor
75 into the sub lOE within the pockets 90 (as shown in broken
l.ines in.Fig. 6) and being retained in these pockets 90 by
the lips 91 which during th~ lowering of the rotor 75 into
the sub lOE are, of course, upwardly directed. By relative
axial movement between the rotor 75 and the sub lOE the
grooves S7 are brought into alignment with the pockets 90
whereupon the rotor 75 and the pipe section lOE are inverted
into the operative orientation when the tool is in use, with
the result that the ball bearings 89 drop along the inclined
faces of the poc~ets 90 to be disposed partially within the
grooves 87. Thereafter, by appropriate relative axial move-
ment between the rotor 75 and the sub lOE the ball bearings
89 are disposed partially within the grooves 87 and partially
within the aligned grooves 88.
As will be appreciated, the disassembly of the axial thrust
20 . bearing 86 is achieved by performing the above-described
steps in.reverse and in the reverse sequence.
The above-described assembly of the axial thrust bearing 86
is initially performed after the sub lOE has been hardened
by appropriate heat treatment but before the rotor 75 has been
so hardened. Thereafter, the assembled axial thrust bearing
86 is mounted in a ~ig (not shown) in which the rotor 75 and
the sub 13E are rotated relative to one another for an
appropriate period of time until the unhardened edge 92 of
. each groove 88 is ground to conform to the shape o~ the ball
bearings 89 with all the ball bearings 89 in solid contact
with the respective grooves 87, 88. The thrust bearing 86
is then disassembled, the rotor 75 is heat treated and
hardened and the thrust bearing 86 is reassembled.
The above-described procedure is preferably adopted in order
, 35 to ensure that when the axial thrust bearing 86 is operatively
. - 15 -
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in use the downward axial thrust on the sub lOE is transmitted
to the rotor 75 through the ball bearings 89 disposed in all
the ball bearing tracks constituted by the aligned grooves 87,
88. If in the production of the rotor 75 the grooves 88 were
formed in their final form, and the rotor 75 was hardened
prior to the initial assembly of the thrust bearing 86 it
is probable that when operatively in use the axial thrust on
thè sub lOE would be transmitted to the rotor 75 only through
the ball bearings 89 in one of.the ball bearing tracks
constituted by the aligned grooves 87, 88, unless the grooves
87, 88 were manufactured to substantially no manufacturing
tolerances. This would, of course, make the manufacture of
the axial thrust.bearing 86 extremely time-consuming and hence
costly.
It will of course be appreciated that alternatively the initial
assembly of the thrust bearing 86 could be performed after
hardening of the rotor 75 but before hardening of the sub lOE
or before hardening of the rotor 75 and sub lOE, with the
unhardened member or members being hardened after the sub-
~ se~uent disassembly and before the re-assembly of the bearing
8~. .
.~ ring 93 and packing 94 are disposed between the rotor 75
and the sub lOE and a split ring 95 retains the rotor 75
within the housing 10, this split ring 95 being disposed
between members 96, 97 with packing 98 and a ball bearing
race 99 also being provided. An O-ring 100 is mounted between
the subs lOE, lOF, and a roller bearing race 101 together
with a seal 102 are provided between the rotor 75 and the
sub lOF.
Screw-threadedly secured on the lower end of the rotor 75 is
a drill bit 103 (Fig. 1) which as is conventional may incor-
porate a plurality of, say, three equally spaced toothed
cones 104, these toothed cones 104 being operatively rotated
during turning of the drill bit 103. Fluid flow ducting
preferably comprising bores disposed between the toothed
~ 2C~
cones 104 is provided in the drill bit 103.
In operation, pressurised drilling mud or other fluid is
continuously pumped down the drill string 11 ~nd hollow
housing 10, this pressurised drilling mud freely flowing
through the openings 47 in the member 41 and through the
openings 47 in the bracket 36. The pressurised drilling mud
likewise freely flows through the openings 53 in the abutment
means 49 and, with the valve 17 in its closed condition shown
in Fig. 3 in which the valve 17 substantially prevents
flow of the pressurised drilling mud down the housing 10,
acts on the valve 17 to move the valve 17 downwardly within
the housing 10, the effective area on which the high pressure
drilling mud operatively acts in so moving the valve 17 down-
wardly being an area having the diameter a (Fig. 3) since an
annular chamber 105 is provided by spacing the lower end of
the sleeve 30 from the inner cylindrical member 19 with radial
vent passages 106 formed in the shaft 31 interconnecting this
annular chamber 105 with an axial vent passage 107 formed in
the shaft 31 and since the high pressure drilling mud opera-
tively flows through the openings 60 in the outer cylindricalmember 21 and between the shoulder 27 and the adjacent end of
the sleeve portion 57 of the inner cylindrical member 19.
This downward movement of the valve 17 includes, of course,
downward movement of the extension member 62 which is
restrained against rotation by the action of the rollers 64
in the axial grooves 66. However, the axial downward movement
of the extension member 62 causes turning of the torque
member 71 as a result of the action of the rollers 68 within
the helical grooves 70. This turning of the torque member 71
is transmitted through the one-way clutch 76 to the rotor 75
which together with the drill bit 103 mounted in the lower
end thereof is thus also turned.
When the flange portion 51 of the abutment means 49 abuts a
lower shoulder 108 further downward movement of the outer
- 17 -
cylindrical member 21 of the valve 17 is thereby prevented,
- this arresting of the downward movement of the outer cylin-
drical member 21 being cushioned by the spring 54. However,
continued downward movement of the first valve member 18
brings the apertures 22, 23 in the inner and outer cylind-
rical members 19, 21 of the valve 17 into overlapping
relationship in which the valve 17 is in its open condition,
thereby equalizing the drilling mud pressure on the upstream
and downstream sides of the valve 17 (Fig. 11~.
It will of course be appreciated that during the above- -
described downward movement of the valve 17 the downward
movement of the shaft 32 results in corresponding downward
movement of the spring support member 41 thereby compressing
the spring 40 to the condition shown in Fig. 10 when the
valve 17 is in its open condition shown in Fig. 11. Under
the influence of the spring 40 the first valve member 18,
together with the second valve member 20, are moved upwardly
within the housing 10, the relatively light spring 59 serving
to maintain the valve 17 in its open condition during this
upward movement of the valve 17. When the flange portion 51
of the abutment means 49 contacts an upper shoulder 109
constituted by the lower end of the sub lOA the second valve
member 20 is thereby restrained against further upward move-
ment, this arresting of the upward movement of the second
valve member 20 being cushioned by the spring 55. However,
under the influence of the spring 40 the upward movement of
the first valve member 18 continues, with compression of the
light spring 59, until the valve 17 is again in its closed
condition ~Fig. 3~, whereupon the above-described cycle of
operations is repeated. The abutment means 49, together with
the shoulders 108, 109, thus constitutes valve actuation means
for causing actuation of the valve 17 to its open condition
when the valve 17 attains its lower position and actuation
of the ~alve 17 to its closed condition when the valve 17
attains its upper position.
- 18 ~
It will of course be appreciated that during the abo~e-
described upward movement of the val~e 17 the extension
member 62 is likewise upwardly moved and is restrained
against rotation by the engagement of the rollers 64 within
the axial grooves 66. Fur~hermore, during this upward move-
ment of the valve 17 the engagement of the rollers 68 in
the helical grooves 70 in the torque member 71 causes turning
of this torque member 71 in the opposite direction. However,
this turning of the torque member 71 in said opposite direction
is not transmitted through the one-way clutch 76 to the rotor
75 50 that the drill bit 103 remains stationary during the
upward movement of the valve 17, the rotation of the drill
bit 103 thus being intermittent during operation of the tool.
It will also be appreciated that during the upward movement of
the valve 17 the pressurised drilling mud flows through the
valve 17, which as described above is in its open condition,
through the hollow torque member 71 and the hollow rotor 75
and is discharged as flushing ~ets through the bores in the
drill bit 103 thereby to clean cuttings and chips from the
bottom of the bore hole 110 (Fig 1) being formed by the
drill bit 103. While the drill bit 103 is being operatively
turned flushing jets of drilling mud are, of course, also
discharged through the bores in the drill bit 103 under the
influence of the downward movement of the vàlve 17 which is
in its closed condition but these flushing jets are of
relatively low pressure and volume, whereas the substantially
higher pressure and ~olume flushing jets of drilling mud while
the valve 17 is in its open condition are provided only while
the drill bit 103 is stationary so that turbulence which
would create a resultant loss in the pressure and energy of
these drilling mud jets with a resultant reduction in the
cleaning action on the bottom of the bore hole 110 being
drilled is substantially minimized.
Figs. 12, 13 and 14 show a modified form of a portion of the
preferred embodiment of the tool as hereinbefore described
with particular reference to Figs. 1 to 11. Fig. 12 sub-
.
s~
stantially corresponds to Fig. 4~ and as will be noted in thismodified form of the preferred embodiment the studs 63 and the
associated rollers 64 are omitted t and instead an endless ball
bearing track or prefera~ly a plurality of angularly spaced
endless ball bearing tracks are provided. As is most clearly
shown in Fig. 13, each of these endless ball bearing tracks
comprisPs one of the axially disposed grooves 66 in the sub lOC
and an axially disposed first groove 111 in the extension
mem~er 62 of the first valve member 18, this first groove 111
being aligned with ~he groove 66 with these aligned grooves
together constituting one run of the endless ball bearing track
the xeturn run of which is constituted by a further groove 112
in the extension member 62. The ends of the grooves 111, 112
in the extension member 62 are interconnected as shown at 113,
and a plurality of freely mova~le.ball bearings 114 are disposed
in the ball bearing track..
.. . ..
Since the freely movable ball bearings 114 disposed within
said one run of the endless ball bearing track are each
disposed partially in the groove 111 in the extension member
62 and partially in the groove 66 in the sub lOC the first
valve member 18 is thereby restrained against.rotation during
operative upward and downward movement of the valv$ 17, the
ball bearings 114 operatively returning along the groove 112
which is wholly in the extension member 62 and which consti-
tutes the return run of the endless ball bearing track.
In this modified form of the preferred embodiment a corres-
ponding endless ball bearing track or preferably a plurality
of corresponding angularly spaced endless ball bearing tracks
each having a plurality of freely movable ball bearings disposed
therein constitute said first and second coupling means for
operatively turning the torque member 71 during upward and
downward movement of the first valve member 18. These endless
ball bearing tracks and associated freely movable ball bearings
substantially correspond to those hereinbefore described and
corresponding primed reference numerals are used to denote
\ - 20 ~ S6~
corresponding parts, the only difference being th~t in each
endless ball bearing track the groov~ 70 in the torque member
71 is helically disposed and the aligned groove 111' which is
provided in the extens;on member 62 is correspondingly heli-
cally disposed, The helically- disposed grooves 70 in the
tor~ue member 71 constitute the first coupling means and the
aligned grooves 111' ;n the extension member 62 constitute the
second coupling means, with the ball ~earings 114' constituting
intermediate means continuously engaging said first and second
coupling means, thereby to pro~ide continuous en~agement
between said first and second coupling means.
Referring now to Figs. 15 and 16 w~ch shbw a further modified
form of the preferred emhodiment, it will be noted that in
this further modified form the studs 63 and the associated
rollers 64 are replaced by an axial spline 115 mounted in the
extension member 62 and which is slida~ly disposed within the
axial groove 66 formed in t~e sub lOC thereby to prevent
rotation of the first valve member 18 during upward and down-
ward movement of thP valve 17. Furthermore, the first coupling
means comprises a helical rib or preferably a plur~lity of
angularly spaced helical ribs 11~ presented by the torque
member 71, each of these ribs 116 being slidably disposed
within an aligned helical groove 117 which is provided in the
extension member 62 and which constitutes the second coupling
means. Annular seals 187 bearing against the member i9 are
provided in recesses in the sub lOC.
Furthermore, as shown in Fig. 15 the spring 40 may be re-
located to surround the torque member 71 and act between the
lower end of the extension member 62 and an upwardly facing
shoulder (not shown) pxesented by the sub lOC, in order to
provide said upward urging of the first valve member 18.
Referring to Fig. 17 which shows a modified form of the one-
way clutch 76, it will be noted that the spring 80, the scxew
81 and the slot 82 as hereinbefore described with reference
. . .
- 21
to Fig. 5 are omitted, and instead a coil spring 176 is
connected between the cage 77 and the upper end portion 74
of the rotor 75 in order resili.ently to maintain the clutch
76 in the condition in which it is ready for driving engage-
ment, the spring 176 being disposea within an annular recess177 in the upper end of t~e upper end portion 74 of the
rotor 75. An annular.sleeve 178 is mounted on the torque
member 71 by means of a clip 179, the sleeve 178 extending
downwardly within the upper end portion 74 of the rotor 75.
Furthermore, the lower end of the lower end portîon 73 of
the torque member 71~and the adjacent face of the rotor 75
are of complementary conical form as indicated by the
reference numeral 180, whereby during downward operative
movement of the valve 17 the. interengagement between the
lS first and second coupling means results in a downward force
on the torque member 71 which causes the conical lower end
of the lower end portion 73 of the torque member 71 to be
urged into mating frictional engagement with the conical face
. of the rotor 75. This assists ;n the driven turning of the
rotor 75 by the torque member 71 through the one-way clutch
76. During upward operati.ve movement of the valve 17 the
interengagement between the first and second coupling means
results in an upward force on the torque member 71 which
causes the conical lower Pnd of the lower end portion 73 of
the torque member 71 to be moved out of mating frictional
engagement with the conical face of the rotor 75 so that the
rotor 75 is not driven by the torque member 71.
In the modified form of the one-way clutch 76 illustrated in
Figs. 18 to 21, inclusive, the adjacent annular faces of the
upper end portion 74 of the hollow, cylindrical rotor 75 and
the surrounding lower end portion 73 of the torque member 71
are each provided with a longitudinally extending groove
or preferably a plurality of longitudinally extending,
angularly spaced grooves 181, a plurality of first annular clutch
plates 182 which alternate with a plurality of second annular
clutch plates 183 being disposed between end rings 184 with
. - 22 -
~2~5~
the outer edges of the plates 182 having teeth 185 which
engage within the grooves 181 in the lower end portion 73 of
the torque member 71 and the inner edges of the plates 183
having teeth 186 which engage within the grooves 181 in the
upper end portion 74 of the rotor 75. Thus during downward
operative movement of the valve 17 the downward force on the
torque member 71 causes the plates 182, 183 to be urged into
matiny frictional engagement with resultant dri~en turning
of the rotor 75 by the torque member 71 through the one-way
clutch 76, while during upward operative movement of the
valve 17 the upward force on the torque member 71 removes
the mating frictional engagement between the plates 182, 183
so that the rotor 75 is not driven by the torque member 71,
Referring now to Figs. 22 to 26, inclusive, in which there is
illustrated a portion of a down hole drilling tool according
to an alternative preferred embodiment of the invention, the
: first valve member 18 of the valve 17 of this alternative
preferred embodiment comprises,a cylindrical member 118 on the
lower end portion of which is screw threadedly mounted a
tubular member 119. The upper end portion of the member 118
has screw threadedly connected thereto a sleeve portion 120 of
a bracket 121 which also comprises parallel diametrically
opposed arms 122 extending axially upwards from the sleeve
portion 120 and the upper ends of which are connected by radial
arms 123 to a centrally disposed, internally screw threaded
boss 124. The lower end of a shaft 125 is screw-threadedly
disposed through this boxx 124 and is secured thereby by a
lock nut 126.
The second valve member 20 of the valve 17 comprises a member
30 127 having a downwardly projecting central rod portion 128 on
which is mounted a tubular sleeve 129 having a plurality of
say, three radial arms 130 on which the member 118 of the first
valve member 18 is slidably mounted thereby to guide the member
11~ during operative axial movement of the first valve member
18 relative to the second valve member 20. The upper end
~;
- .
~2~S~
portion of the member 127 is in the form of a short cylind-
rical stub 131, two diametrically opposed and axially extending
limb portions 132 of a sleeve member 133 being mounted on the
stub 131 and being connec~ed thereto by means of a transversely
extending pin 134. The upper end portion of the sleeve 133
presents a downward directed shoulder 135, with a relatively
light spring 136 being mounted on the shaft 125 between this
shoulder 135 and the upper face of the boss 124.
As in the case of the preferred embodiment hereinbefore
described with particular reference to Figs. 1 to 11, inclusive,
a coil compression spring 137 acts on the shaft 125 upwardiy
to urge the first valve memher 18. This spring 137 acts
between a collar 138 and the upper end face of a member 139
the lower end portion of which presents an annular flange 140
with the outer end portion 141 , this flange 140 being radially
disposed and being operatively clamped between a shoulder 142
and a sleeve 143~ e collar 138 is mounted on the shat 125
in a manner corresponding to the manner of mounting of the
spring support member 41 on the shaft 32, and corresponding
reference numerals are used to denote corresponding parts.
Below the sleeve 143 is a liner 144 the lower end portion of
.. .. . . . ..
which is provided with recessing comprising an axially exten-
ding slot or preferably a plurality of axially extending r
annularly spaced slots 145, the purpose of which is hereinafter
more fully explained. Instead o the collar 72 the upper end
of the torque member 71 is provided with a shock absorber
assembly which may be a multi-stage assembly comprising, as
shown in Fig. 21, a spring 146 disposed within an enlarged
.diameter chamber 147 in the upper end portion of the hollow
torque member 71, this spring 146 being between a plate 172
at the bottom of the chamber 147 and the base 148 of a cylin-
drical cup 149 slidably mounted within the chamber 147. A
further spring 150 is disposed within the cup 149 between the
base 148 and a plug 151 slidably mounted in the cup 149, a
transverse pin 152 being disposed through the base 148 of the
cup 149 with the ends of the pin 152 in axially elongated
- 2~ -
slots153 in the upper end portion of the torque member 71
thereby to limit slidable movement oE the cup 149 within the
upper end portion of the torque member 71, and a further
transverse pin 154 being disposed through the plug 151 with
the ends of the pin 154 in axially elongated slots 155 in
the cup 149 thereby likewise to limit slidable movement of
the plug 151 within the cup 149. The springs 146, 145 may
be of the Belleville type. Below the sleeve portion 120
of the bracket 121 there is mounted on the member 118 a
plurality of piston rings 156 in sliding contact with the
liner 144, and a bypass port or preferably a plurality of
angularly spaced bypass ports 157 is provided in the member
118 below the piston rings 156. Annular wear rings 188 are
mounted on the member 118 below the ports 157.
The member 139 is screw threadedly connected to the lower end
portion of a sleeve 158 the upper end portion of which is
screw threadedly connected to a plug member 159, with the
sleeve 158 constituting a casing within which the spring 137
is disposed thereby, in this preferred embodiment, to
facilitate assembly of the tool with minimized abrasion on
the spring 137 during this assembly and disassembly of the
tool~ By replacing a screw 160 in the plug member 159 with
a longer screw 155 this longer screw may be caused to operate
on the upper end of the shat 125 thereby to move the shaft
125 downwardly and thus remove the influence of the spring
137 from the shaft 125. By then separating the subs lOA, lOB
and removing the lock nut 12Ç the shaft 125 may be disconnec-
ted from the boss 124 in order conveniently to replace the
assembly comprising the shaft 125, the member 139, the
sleeve 158, the plug member 159, the collar 138 ard the spring
137, wrench flats 161 formed on the shaft.l25 being exposed
when the shaft 125 is moved downwardly as described above for
engagement by a suitable form of wrench (not shown) to
facilitate unscrewing of the shaft 125 from the boss 124.
In operation of this alternative preferred embodiment of
- ~5 -
~2~'~35~
Figs. 22 to 26, inclusive, pressurized drilling mud or other
fluid is, as in the case of the operation of the preferred
embodiment hereinbefore descri~ed with reference ko Figs. 1
to 11, inclusive, continuously pumped down the drill string
11 and elongated hollow housing 10, this pressurized drilling
mud freely flowing through an opening or angularly spaced
openings 162 in the flange 140 of the member 139 and, with
the valve 17 in its closed condition shown in Fig. 23, acting
on the valve 17 to move t~e valve 17 downwardly within the
housing 10.
As hereinbefore described with reference to Figs 1 to 11,
inclusive, 12, 13 and 14, or 15 and 16, this downward movement
of the valve 17 causes turning of the torque member 71 in said
one direction with resultant turning of the rotor 75 and the
drill bit 103 through the one-way clutch 76.
When the lower end of the rod portion 128 of the second valve
member 20 contacts the plug 151 this plug 151 is urged down-
wards against the influence of the spring 150 and the cup 149
together with the plug 151 is then urged downwards against
the influence of the spring 146, thereby arresting the downward
movement of the second valve member 20 in a cushioned manner.
Continued downward movement of the first valve member lS results
in opening of the valve 17 ~Fig~ 26), as hereinbefore described
with reference to Figs. 1 to 11, inclusive.
As the downward movement of the second valve member 20 is being
arrested by the multi-stage shock absorber incorporating the
springs 146, 150 the uppermost of the piston rings 156 passes
below the upper ends of the slots 1~5 in the liner 144, where-
upon the high pressure drilling mud flows around the valve 17,
3u into these slots 145 and through the bypass ports 157 to act
on the downstream side of the valve 17. This equalization of
the drilling mud pressure on the upstream and downstream sides
of the valve 17 further assists in arresting the downward
movement of the valve 17.
- 26 -
~gS~
,
The valve 17 is then moved upwards in the housing 10 under the
influence of the spring 137 which has, of course, been COM-
pressed during the downward movement o:E the valve 17 as in
the preferred embodiment hereinbefore described with particular
re~erence to Figs. 1 to 11, inclusive. During this upward
movement of the valve 17, the valve 17 is of course maintained
in its open condition under the influence of the relatively
light spring 136. When the upper end of the sleeve 133 of the
second valve member 20 contacts a resiliently deformable ring
1~ 163 disposed between the upper end of the sleeve 133 and the
mernber 139 the second val~e member 20 is thereby restrained
against further upward movement, this arresting of the
upwar~ movement of the second valve member 20 being cushioned
by the resiliently deformable ring 163. However, under the
influence of the spring 137 the upward movement of the first
valve member 18 continues, with compression of the relatively
light spring 136, until the valve 17 is again in its closed
condition (Fig.23 ), whereupon the above-described cycle of
opexations is repeated.
During the above-described upward movement of the valve 17 the
torque member 71 is turned in the opposite direction with, as
a result of the one-way clutch 76, ~he rotor 75 and the drill
bit 103 being stationary as is fully described hereinbefore
with reference to the preferred embodiment of Figs. 1 to 11,
inclusive, the rotation of the drill bit 103 thus again being
intermittent during operation of the tool, and high pressure
and volume drilling mud flushing jets again servin~ to provide
improved cleaning of the bottom of the bore hole 110 being
drilled by the drill bit 103 while the drill bit 103 is
stationary.
Referring to Fig. 27 which shows a modified form of the
assembly incorporating the spring 137, this modified assembly
comprises a cylinder 164 which is screw-threadedly connected
to the member 139. The upper end portion of the cylinder 164
is closely spaced from the inner wall of the sub lOA to
- 27 -
\
provide a restricted annular throat 165 and this throat 165
is in communication with the upper end portion of the interior
of the cylinder 164 through a port or prefera~ly a plurality
of angularly spaced ports 166. Within the cylinder 164 is
slidably mounted a piston 167 to which the upper end of the
shaft 125 is screw t~readedly conn~cted, the shaft 125 being
sealed relative to the piston 167 by an O~ring 168, and piston
rings 169 together with a wear~ring 170 ~eing mounted on the
piston 167 in sliding contact with the inner wall of the
cylinder 164.
An opening or angularly spaced openings 171 are provided in
the cylinder 164 below the piston 167, so that in operation
high pressure drilling mud passes through these openings I71
and acts on the piston I67 upwardly to urge the piston 167
15. and hence also the shat 125, the high pressure drilling mud
as it flows through the restricted annular throat 165 creating
a venturi effect which results in reduced pressure in the
upper end portion of the interior of the cylinder i64 above
the piston 167. : -
Thus, this modified form of Fig. 22 serves upwardly to urge
the shaft 12~, and in some cases this modified form of Fig. 22
may be preferable to the assembly incorporating the spring 137
since it avoids potential problems of breakage or damage to
the spring 137.
In a further alternative embodiment ~not shown) the first
coupling means comprising the helically disposed grooves 70
may be provided in the first valve member 18 with the second
coupling means which i5 continuously engaged with the first
coupling means being presented by the housing 10 or a member
fixedly mounted thereon, and with the torque member 71
continuously connected to the first valve member 18 by axial
splining. Thus, on downward and upward movement of the first
valve member 18 relative to the torque member 71 the first
- ~8 -
56~
valve member 18 and hence also the torque member 71 is turned
in the appropriate direction by the interaction of the first
and second coupling means.
In such a further alternative embodiment the first valve
member 18 is of course operatively rotated, but if this i5
not desirable the first valve member 18 could be coupled to
an intermediate member throu~h a connection such that -the
intermediate member and the first valve member 18 operatively
move upwardly and downwardly as a unit, but with the inter-
mediate member being rotatable relative to the first valve
member 18. In this case the first coupling means with which
the second coupling means is continuously engaged and which
comprises the helically disposed grooves 70 is provided in the
intermediate member, and the axial splining connection of the
torque member 71 is with the intermediate member.
It will of course be appreciated that th~ modified form of the
means for upward urging of the valve 17 as shown in Fig. 27
may be substituted in the pxeferred embodiment hereinbefore
described with reference to Figs. 1 to 11, inclusive, or the
modified forms thereof of Figs. 12, 13 and 14, or 15 and 16.
Also,(the modified forms of the one-way clutch 76 as shown in
Fig. 17 or Figs. 18 to 21, inclusive, could of course be
substituted in the alternative preferred embodiment herein-
before described with reference to Figs. 22 to 26, inclusive,
or the modified form thereof of Fig. 27. Furthermore, in any
particular case the form of the valve 17 to be used will be
at least partly dependent on the diameter of the tool and the
viscosity of the drilling mud operatively to be used with the
tool.
