U.S. patent number 3,761,145 [Application Number 05/232,134] was granted by the patent office on 1973-09-25 for seal means for drill bit bearings.
This patent grant is currently assigned to G. W. Murphy Industries, Inc.. Invention is credited to Percy W. Schumacher, Jr..
United States Patent |
3,761,145 |
Schumacher, Jr. |
September 25, 1973 |
SEAL MEANS FOR DRILL BIT BEARINGS
Abstract
A drill bit including a roller cutter mounted on a greased
bearing journal having a grease seal ring therearound and resilient
means mounted between the seal ring and bearing journal to urge the
seal ring against a sealing surface on the cutter in such a manner
that the seal ring may be forced away from the cutter surface by
some predetermined pressure from within the cutter but wherein the
seal ring arrangement provides a substantially positive seal from
pressures externally of the cutter to prevent detritus or other
foreign material from entering into the bearing area interiorly of
the drill bit cutter. Elastomeric material may be provided between
the seal ring and the cutter sealing surface. The abstract is
neither intended to define the invention of the application which,
of course, is measured by the claims, nor is it intended to be
limiting as to the scope of the invention in any way.
Inventors: |
Schumacher, Jr.; Percy W.
(Houston, TX) |
Assignee: |
G. W. Murphy Industries, Inc.
(Houston, TX)
|
Family
ID: |
22871995 |
Appl.
No.: |
05/232,134 |
Filed: |
March 6, 1972 |
Current U.S.
Class: |
384/94; 384/489;
277/336; 175/371; 277/382 |
Current CPC
Class: |
F16J
15/344 (20130101); F16C 33/78 (20130101); F16C
33/72 (20130101); E21B 10/25 (20130101); F16C
2352/00 (20130101) |
Current International
Class: |
F16J
15/34 (20060101); F16C 33/76 (20060101); F16C
33/78 (20060101); E21B 10/22 (20060101); E21B
10/08 (20060101); F16c 033/76 () |
Field of
Search: |
;308/8.2,187.1
;175/371,372 ;277/92,96 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myhre; Charles J.
Assistant Examiner: Grossman; Barry
Claims
What is claimed is:
1. A roller cutter earth boring bit comprising:
a bearing shaft arranged on said bit,
a roller cutter mounted on said shaft,
a seal ring encircling said shaft,
the seal ring having a contoured surface and a sealing face,
a sealing surface on said cutter,
resilient means between the shaft and the seal ring,
said resilient means being in frictional contact with said seal
ring and shaft to insure that said resilient ring and seal ring
will not rotate,
said resilient means coacting with the shaft and and contoured
surface of said seal ring to bias the seal ring face into sealing
engagement with the sealing surface on said cutter.
2. A roller cutter earth boring bit according to claim 1
wherein
the said seal ring contoured surface comprises an inner conical
surface.
3. A roller cutter earth boring bit according to claim 2
wherein
the shaft has an oppositely tapered conical surface confronting the
inner conical surface of the seal ring and said resilient means is
located between said conical surfaces.
4. A roller cutter earth boring bit according to claim 1
wherein
the seal ring is biased into engagement with the cutter sealing
surface so that there is greater contact pressure between the outer
margin of the seal ring face and the cutter sealing surface than
there is between the inner margin of the seal ring face and the
cutter sealing surface.
5. A roller cutter earth boring bit comprising:
a bearing shaft arranged on said bit,
a roller cutter mounted on said shaft,
a sealing surface on said cutter,
said shaft having an outer tapered surface,
a seal ring having an inner tapered surface and a sealing face and
being in encircling relationship to the shaft tapered surface,
resilient means coacting with the tapered surfaces to bias the seal
ring into engagement with the cutter sealing surface so that there
is greater contact pressure between the outer margin of the seal
ring face and the cutter sealing surface than there is between the
inner margin of the seal ring face and the cutter sealing
surface,
said resilient means being in frictional contact with said seal
ring and shaft to insure that said resilient ring and seal ring
will not rotate.
6. An earth boring bit cutter assembly comprising:
a cutter support,
journal means on said support,
a roller cutter on said journal means,
a sealing surface on said cutter,
a seal ring encircling said journal means,
said seal ring having an inner conical surface and a sealing
face,
resilient means between the journal means and the seal ring,
said resilient means being in frictional contact with said seal
ring and journal means to insure that said resilient ring and seal
ring will not rotate,
said resilient means coacting with said journal means and conical
surface of said seal ring to bias said seal ring face into sealing
engagement with the sealing surface on said cutter.
7. An earth boring bit cutter assembly comprising:
a cutter support,
journal means on said support,
a roller cutter on said journal means,
a sealing surface on said cutter,
the journal means having an outer tapered surface,
a seal ring having an inner tapered surface and a sealing face and
being in encircling relationship to the tapered surface on said
journal means, and
means adapted to coact with the tapered surfaces to bias the seal
ring into engagement with the cutter sealing surface so that there
is greater contact pressure between the outer margin of the seal
ring face and the cutter sealing surface than there is between the
inner margin of the seal ring face and the cutter sealing surface
and said seal ring tends to pivot about an end of its sealing face.
Description
SUMMARY
This invention relates to a seal arrangement between a roller
cutter and the bearing journal on which it is mounted, to confine a
lubricant in the bearing area interiorly of the cutter and to keep
formation cuttings and other detritus out of such bearing area.
It is an object of this invention to provide a new and improved
seal arrangement for drill bit cutter bearings.
Another object is to provide a drill bit cutter seal arrangement
which requires small axial space so that more bearing capacity can
be utilized for the cutter.
Another object is to provide a drill bit cutter seal arrangement
which may function somewhat as a check valve in that the seal may
be forced open by a predetermined grease pressure from within the
cutter but which cannot readily be forced open by external pressure
or from detritus being wedged or lodged around the seal externally
of the cutter.
Another object is to provide a drill bit cutter seal means which
does not rotate with respect to the shaft so that external abrasive
wear thereof is alleviated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal sectional view through a drill bit cutter
together with its associated bearing journal and support
illustrating a seal arrangement constructed in accordance with this
invention.
FIG. 2 is a fragmentary enlarged view of that portion of FIG. 1
appearing within the broken circle 2.
FIG. 3 is a longitudinal sectional view through another type of
drill bit cutter together with its associated bearing journal and
support illustrating the seals of the invention employed in
opposite ends of such cutter.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 and 2, there is shown at 10 a cone type of
well drill of generally conventional construction comprising a bit
head 11 and a threaded shank 12 for connection to a drill stem (not
shown). A cutter support 13 extends downwardly from the bit head
and a bearing journal 14 extends downwardly and inwardly from the
support 13.
A roller cutter 15 is rotatably mounted on the bearing journal 14
on friction bearing 16 and 17 and ball bearings 18. After the ball
bearings have been inserted into place, a retaining pin 19 serves
to keep them in place. The roller cutter 15 may be made of alloy
steel and may have cutting inserts 30 thereon, or other suitable
cutting elements.
The cutter 15 is counterbored as at 21 to provide a radially
extending sealing surface 22. The bearing journal 14 may have a
tapered or conical surface 23. A seal ring 24 is disposed within
the counterbore 21 and has a substantially radially extending seal
face 25. The seal ring 24 may have its inner surface contoured as
at 26 to form a conical surface or the like with the result that
the seal ring portion 27 opposite the seal face 25 is
attenuated.
A resilient ring 28 which may be an O-ring or the like is provided
between the bearing journal 14 and the seal ring 24. The resilient
ring 28 may have a round cross section in its relaxed condition and
may be made of Buna-N having a 70 durometer hardness or any other
suitable elastomer.
When the cutter 15 is installed in position on the journal 14, the
resilient ring 28 is distorted and coacts with conical surfaces 23
and 26, as is clearly shown in FIGS. 1 and 2, to bias the seal ring
24 against the cutter sealing surface 22 with a force of from 50 to
500 pounds. I have found from actual field experience that a force
of approximately 100 to 150 pounds is satisfactory for bits in the
range of 7 to 10 inches in diameter.
In addition to the axial load applied by the resilient ring 28 to
the seal ring 24 against the sealing surface 22, the resilient ring
when so distorted exerts a radial stress on the seal ring 24. Since
the ring 24 is attenuated at 27 opposite the ring seal face 25, the
ring 24 which may be made from a stiff but flexible material such
as plastic or metal, will be expanded radially more at the portion
27 than at the seal face 25 with the result that the ring 24 tends
to pivot about point 29 so that there is greater contact pressure
between the outer margin of the seal ring face 25 and the cutter
sealing surface 22 than there is between the inner margin of the
seal ring face 25 and the cutter sealing surface 22. This is to
insure that there is no initial gap between the seal ring face 25
and the cutter sealing surface 22 at point 29 because if a gap
exists at this point, abrasive particles of formation may work
their way between the seal ring face and cutter surface 22 and
gradually abrade away these surfaces destroying the seal and
contaminating the cutter grease resulting in bearing failure.
If desired, an elastomeric material may be disposed on surface 22,
on seal ring face 25 or between the surface and ring face to insure
better sealing effectiveness under certain conditions.
The resilient ring 28 is in frictional contact with the conical
surface 23 of the journal 14 and the conical surface 26 of the seal
ring 24 thereby insuring that the resilient ring 28 and seal ring
24 will not rotate with respect to the journal 14, to alleviate
external abrasive wear of the seal means.
In most instances the seal ring face 25 is stepped or otherwise cut
away as at 25a to insure that the seal ring 24 may be more readily
forced open by a predetermined grease pressure from within the
cutter.
It will also be appreciated that in some instances, the journal
area confronting the inner surface 26 of the seal ring 24 need not
be conical as shown at 23, but may be cylindrical or the like and
still provide the improved cutter seal arrangement of the
invention.
Referring to FIG. 3, a cutter support 40 is shown having a base 41
suitable for welding or otherwise being secured to a bit head (not
shown). The support 40 is in the form of a yoke or saddle having
legs 42 and 43. A bearing journal 44 extends between legs 42 and 43
and may be secured to the support by bolt means 45.
A roller cutter 46 is rotatably mounted on the journal 44 on roller
bearings 47, 48 and 49 and ball bearings 50 in suitable races.
Toward one end of the journal 44 is a flange 51 having a conical
surface 52. The cutter 46 is counterbored as at 53 to provide a
radially extending sealing surface 54. A seal ring 55 encircles the
journal 44 and conical surface 52 and has a sealing face engaging
the surface 54. The seal ring has a conical inner surface 56
oppositely disposed to the conical surface 52. A resilient ring 57
is disposed between these conical surfaces and serves to bias the
seal ring against the cutter sealing surface 54 in a manner
identical to that described in the structures shown in FIGS. 1 and
2.
A similar seal arrangement is shown at the other end of the cutter
46 comprising a seal ring 60, a resilient ring 61 and a journal
insert 62 which may be pressed on or otherwise secured to the
journal 44. This seal arrangement also functions identically to
that described in the construction shown in FIGS. 1 and 2.
The seal arrangement of the invention thus provides a seal ring
which occupies small axial space so that more bearing capacity may
be provided in the limited space available, and a cutter seal which
may act somewhat as a check valve in that the seal may be forced
open by a predetermined grease pressure interiorly of the cutter
but which cannot readily be opened by external pressure or by
detritus around the seal externally of the cutter.
The foregoing disclosure and description of the invention are
illustrative and explanatory thereof, and various changes in the
size, shape and materials, as well as in the details of the
illustrated construction, may be made within the scope of the
appended claims without departing from the spirit of the
invention.
* * * * *