US3761145A - Seal means for drill bit bearings - Google Patents

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.

Description

United States Patent [191 Schumacher, Jr.

[ SEAL MEANS FOR DRILL BIT BEARINGS [75] Inventor: Percy W. Schumacher, Jr., Houston,

Tex.

[73] Assignee: G. W. Murphy Industries, Inc., Houston, Tex.

[22] Filed: Mar. 6, 1972 [21] Appl. No.: 232,134

[52] U.S. Cl 308/82, 175/371, 277/92,

[51] Int. Cl. Fl6c 33/76 [58] Field of Search .1. 308/82, 187.1; 175/371, 372; 277/92, 96

[56] References Cited UNITED'STATES PATENTS 3,449,024 6/1969 Lichte 308/82 3,004,807 10/1961 Kniepkamp... 308/l87.1

3,467,448 9/1969 Galle 1 308/82 3,572,452 3/1971 Winberg... 308/82 3,604,523 /1971 Lichte 1 308/82 3,612,196 10/1971 Dixon 308/82 3,656,764 4/1972 Robinson 308/82 3,140,902 7/1964 Herbst 1 1 308/361 3,307,645 3/1967 Hildebrandt 308/187.1

[ Sept. 25, 1973 1/1968 Ferrand ..308/l87.1 5/1970 Mancel 277/96 [5 7 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.

7 Claims, 3 Drawing Figures SEAL MEANS FOR DRILL BIT BEARINGS 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 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, there is shown at a cone type of well drill of generally conventional construction comprising a bit head 11 and a threadedshank 12 for connection to a drill stern (not shown). Acutter support 13 extends downwardly from the bit head and abearingjournal 14 extends downwardly and inwardly from thesupport 13.

Aroller cutter 15 is rotatably mounted on thebearing journal 14 on friction bearing 16 and 17 andball bearings 18. After the ball bearings have been inserted into place, a retainingpin 19 serves to. keep them in place. Theroller cutter 15 may be made of alloy steel and may have cutting inserts 30 thereon, or other suitable cutting elements.

Thecutter 15 is counterbored as at 21 to provide a radially extendingsealing surface 22. Thebearing journal 14 may have a tapered orconical surface 23. Aseal ring 24 is disposed within thecounterbore 21 and has a substantially radially extendingseal face 25. Theseal ring 24 may have its inner surface contoured as at 26 to form a conical surface or the like with the result that theseal ring portion 27 opposite the seal face is attenuated.

Aresilient ring 28 which may be an O-ring or the like is provided between thebearing journal 14 and theseal ring 24. Theresilient 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 thecutter 15 is installed in position on thejournal 14, theresilient ring 28 is distorted and coacts withconical surfaces 23 and 26, as is clearly shown in FIGS. 1 and 2, to bias theseal ring 24 against thecutter sealing surface 22 with a force of from 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 theresilient ring 28 to theseal ring 24 against the sealingsurface 22, the resilient ring when so distorted exerts a radial stress on theseal ring 24. Since thering 24 is attenuated at 27 opposite thering seal face 25, thering 24 which may be made from a stiff but flexible material such as plastic or metal, will be expanded radially more at theportion 27 than at theseal face 25 with the result that thering 24 tends to pivot aboutpoint 29 so that there is greater contact pressure between the outer margin of theseal ring face 25 and thecutter sealing surface 22 than there is between the inner margin of theseal ring face 25 and thecutter sealing surface 22. This is to insure that there is no initial gap between theseal ring face 25 and thecutter sealing surface 22 atpoint 29 because if a gap exists at this point, abrasive particles of formation may work their way between the seal ring face andcutter 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 onsurface 22, onseal ring face 25 or between the surface and ring face to insure better sealing effectiveness under certain conditions.

Theresilient ring 28 is in frictional contact with theconical surface 23 of the journal 14' and theconical surface 26 of theseal ring 24 thereby insuring that there silient ring 28 andseal ring 24 will not rotate with respect to thejournal 14, to alleviate external abrasive wear of the seal means.

In most instances theseal ring face 25 is stepped or otherwise cut away as at 25a to insure that theseal 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 theinner surface 26 of theseal 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, acutter support 40 is shown having a base 4] suitable for welding or otherwise being secured to a bit head (not shown). Thesupport 40 is in the form of a yoke orsaddle having legs 42 and 43.'Abearing journal 44 extends betweenlegs 42 and 43 and may be secured to the support by lbolt means 45.

Aroller cutter 46 is rotatably mounted on thejournal 44 onroller bearings 47, 48 and 419 andball bearings 50 in suitable races. Toward one end of thejournal 44 is a flange 51 having aconical surface 52. Thecutter 46 is counterbored as at 53 to provide a radially extendingsealing surface 54. Aseal ring 55 encircles thejournal 44 andconical surface 52 and has a sealing face engaging thesurface 54. The seal ring has a conicalinner surface 56 oppositely disposed to theconical surface 52. Aresilient ring 57 is disposed between these conical surfaces and serves to bias the seal ring against thecutter 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 thecutter 46 comprising aseal ring 60, aresilient ring 61 and ajournal insert 62 which may be pressed on or otherwise secured to thejournal 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.

What is claimed is:

l. 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 wherein the said seal ring contoured surface comprises an inner conical surface. 3. A roller cutter earth boring bit according toclaim 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 i 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 4 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.

Claims (7)

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.

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