CN101384792A - Sealed Blade Rings for Rolling Cone Drilling Bits - Google Patents

Abstract

A formation drilling bit has a bit body with a suspension support pin. A cutting edge ring is mounted on the support pin. The cutting edge ring has an inner diameter larger than the outer diameter of the support pin, thereby defining a gap between the cutting edge ring and the support pin to allow the cutting edge ring to float relative to the axis of the support pin. An inner seal is sealingly engaged with the support pin and the inner diameter of the cutting edge ring. A roller cone is rotatably mounted on the support pin, the roller cone having a cavity containing an outer sealing groove. The outer seal, located within the outer sealing groove, dynamically seals with the outer diameter of the cutting edge ring. An anti-rotation element engages a portion of the cutting edge ring to prevent rotation of the cutting edge ring.

Description

Sealed Blade Rings for Rolling Cone Drilling Bits

priority statement

This application claims priority to US Provisional Patent Application Serial No. 60/756,901, filed January 6,2006.

technical field

The present invention relates generally to rolling cone formation drilling bits, and more particularly to a blade ring mounted between support pins and seals for resistance to wear and corrosion.

Background technique

A typical rolling cone formation drilling bit has a bit body with three roller cone bit palms. A support pin protrudes from the palm of each roller cone bit, and a cone is rotatably mounted on the support pin. The bearing surface between the cavity of the cone and the bearing pin is filled with lubricant. A seal sits between the cone and the bearing pin to seal lubricant inside and prevent ingress of drilling fluid.

Seals of many configurations have been proposed and used. A seal includes an elastomeric ring positioned in a groove in a cone near a mouth of a cavity. The ring normally rotates with the cone and seals against the stationary support pins. The ring and seal groove are designed to provide a selected contact pressure of the inner diameter of the ring to the support pin. During operation, a large downward force is applied to the bit, resulting in a higher contact pressure on the underside of the support pin than on the upper side. Also, during operation, there may be slight movement of the cone relative to the axis of the support pin. This movement causes a change in the contact pressure on both the bearing and the seal. Variations in contact pressure can cause overheating and wear in certain areas of the seal, reducing life. Also, cuttings from the formation can contact portions of the seal, often causing it to wear.

US Patents 5,005,989, 5,570,750 and 4,934,467 disclose mounting a rigid blade ring on the support pin for engaging the inner diameter of the seal ring. The blade ring is made of a harder material than the support pins to reduce wear on the seal ring. In the FIG. 7 embodiment of the '989 patent, the blade ring is positioned on the support pin and is secured relative to the support pin by a vulcanized layer.

Contents of the invention

The formation drilling bit of the present invention has a rigid blade ring mounted on support pins. The blade ring has an inner diameter greater than the outer diameter of the support pin so as to define a gap between the blade ring and the support pin to allow the blade ring to float relative to the axis of the support pin. An inner seal is in sealing engagement with the support pin and the inner diameter of the blade ring. A cone is rotatably mounted on the support pin, the cone having a cavity containing an outer sealing groove. An outer seal is seated in the outer seal groove and is in dynamic sealing engagement with the outer diameter of the blade ring. An anti-rotation element mounted to a portion of the drill body engages a portion of the blade ring to prevent rotation of the blade ring.

Preferably, the blade has a uniform thickness around its periphery. In a preferred embodiment, the anti-rotation element is a pin having an axis perpendicular to the portion of the seal ring it engages. Also, in a preferred embodiment the blade ring has a radially extending flange that abuts the palm of the roller cone bit. The flange on the blade ring is partially recessed into an annular groove formed on the palm of the roller cone bit. Preferably, the inner seal is seated in a groove formed on the support pin.

Description of drawings

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of a cone and support pin of a formation drilling bit constructed in accordance with the present invention.

FIG. 2 is a partially enlarged view of a portion of the support pin and the cone shown in FIG. 1. FIG.

Figure 3 is an elevational view of the drill bit of Figure 1 with a portion of the blade ring removed from the drill bit.

Detailed ways

Referring to FIG. 1, the drill bit 11 has a main body composed of a plurality of roller cone bit legs 13, but only a part of a roller cone bit leg is shown in the figure. Typically, the drill bit 11 has three roller cone bit legs 13, each roller cone bit leg 13 being suspended from the bit body. A support pin 15 comprising a cylindrical element extends downwardly from the roller cone bit leg 13 towards the axis of rotation of the bit 11 .

An annular groove 17 is formed around the junction of the roller cone bit leg 13 and the support pin 15 . The dimple 17 is formed on a portion of the roller cone bit leg 13 referred to as the last machined surface 19 . The final machined surface 19 is a substantially flat surface lying in a plane perpendicular to the bearing pin axis 23 . A final machined surface 19 extends radially outwards from the annular groove 17 . A portion of the last machined surface 19 on the underside of the roller cone bit leg 13 is referred to as the leg edge 12 . The dimple 17 has a radial width approximately equal to the radial width of the last machined surface 19 at the palm bottom edge 21 .

A rigid blade ring 25 is mounted on the support pin 15 at the junction with the bit leg 13 of the roller cone bit. The blade ring 25 is preferably an L-shaped element in cross-section having a cylindrical portion 27 extending around the support pin 15 and a flange portion 29 extending radially outward from the cylindrical portion 27 . The flange portion 29 is located within the recess 17 and has a matching profile. In this embodiment, the flange portion 29 has a thickness approximately twice the depth of the recess 17 so that it protrudes a short distance forward from the last machined surface 19 . In this embodiment, the flange portion 29 is thicker than the cylindrical portion 27 . The cylindrical portion 27 tapers at its front end. The thickness of the cylindrical portion 27 is preferably uniform around the periphery of the ring 25 .

In a preferred embodiment, the inner diameter of cylindrical portion 27 is slightly larger than the outer diameter of support pin 15 by a few thousandths of an inch. The clearance between the inner diameter of the cylindrical portion 27 and the outer diameter of the support pin 15 allows slight, non-rotational movement or float of the blade ring 25 relative to the axis of the support pin 15 . An inner seal 31 , in this embodiment an elastomeric O-ring, sits in a groove formed in the support pin 15 , sealing against the inner diameter of the cylindrical portion 27 of the blade ring 25 . The inner seal 31 preferably has a uniform cross-sectional thickness around its periphery.

An anti-rotation element prevents rotation of the blade ring 25 relative to the support pin 15 . In this embodiment, a dimple or slot 33 is formed in one or more places on the periphery of the flange portion 29 as shown in FIG. 3 . The slot 33 is semicircular, although it could be of a different shape, or could be a complete hole if desired. An anti-rotation pin 35 ( FIGS. 1 and 2 ) engages the slot 33 and is inserted into the final machined surface 19 to prevent rotation of the blade ring 25 relative to the support pin 15 .

Referring again to FIG. 1 , a cone 37 is rotatably mounted to each support pin 15 . The cone 37 has an outer surface containing a plurality of cutting elements 39 which may be teeth machined into the outer surface of the cone 37 . Alternatively, the cutting element 39 may also be a tungsten carbide insert pressed into a mating hole in the outer surface of the cone 37 . The cone 37 has a cone cavity 41 that closely fits the support pin 15 .

A wide variety of different bearing arrangements between the cone 37 and the support pin 15 may be employed. In the example shown, a set of rear cylindrical roller bearings 43 are carried in grooves in the cavity 41 for engaging the support pin 15 . This embodiment also discloses a set of middle roller bearings 45 engaging the smaller diameter portion of the support pin 15 and a set of front roller bearings 47 engaging the smaller diameter portion of the support pin 15 . A thrust washer 49 sits on the thrust shoulder of the bearing pin 15 for engaging a mating surface within the cone cavity 41 . The cone 37 is retained on the support pin 15 by a plurality of balls 51 that engage mating recesses in the cone cavity 41 and on the support pin 15 .

The cone cavity 41 is filled with lubricant supplied to the space between the cone 37 and the support pin 15 through a channel (not shown) from a lubricating oil tank and a pressure compensator (not shown). Various seals are used to seal the lubricant inside the cone cavity 41 to prevent erosion from the drill bit fluid from the outside. In this embodiment, the seal comprises an elastomeric seal 53 located inside a seal groove 55 formed near the entrance or mouth of the cone cavity 41 . Referring to FIG. 2 , the sealing groove 55 preferably has parallel side walls, each of which lies in a plane perpendicular to the axis of the support pin 15 . Seal 53 , also referred to as an “outer” seal 53 , has an inner diameter portion that slidably engages the outer surface of blade ring cylindrical portion 27 . The sealing member 53 generally rotates synchronously with the cone 37 , but there may also be a certain rotation or sliding relative to the cone 37 . In this embodiment, the seal 53 has generally planar front and rear sides parallel to each other and semi-cylindrical chamfered inner and outer diameter portions. In this embodiment, the distance between the inner and outer diameter portions is significantly greater than the distance between the flat front and rear portions, but other shapes are possible.

Still referring to FIG. 2 , cone 37 has a mouthed back that surrounds cone cavity 41 . The back includes an inner back portion 57 extending radially outwardly from the mouth of the cavity 41 relative to the bearing pin axis 23 ( FIG. 1 ). The inner back portion 57 is not flat; rather, in this embodiment it is curved to match the contour of the blade ring flange 29 . The inner back portion 57 curves around the blade ring flange 29 and extends rearwardly to define an annular rib 59 adjacent the outer diameter of the blade ring flange 29 . There is a slight gap between the inner back portion 57 and the blade ring 25 . In this embodiment, the cone back includes an outer portion 61 that is recessed from the annular rib 59 in a forward direction. The outer back portion 61 extends radially outward to intersect a gage surface 65 of the cone 37 .

An annular rib 59 extends over a portion of the blade ring flange 29 , having a plane separated from the last machined surface 19 by a small gap. The width of this gap is smaller than the thickness of the flange 29, thereby limiting the entry of drilling chips. The outer seal groove 55 is spaced slightly forward from the inner back portion 57 toward the bit rotational axis. The portion of the cone 37 between the inner back portion 57 and the groove 55 is a thin flange 62 which separates the outer seal 53 from the blade ring flange 29 . Outer seal 53 thus does not contact blade ring flange 29 .

The anti-rotation pin 35 has a flat surface which is separated from the cone annular rib 59 by a small gap. In this embodiment, the surface of the anti-rotation pin 35 is substantially flush with the portion of the last machined surface 19 radially outward from the annular groove 17 which receives the blade ring flange 29 . The hole for receiving the anti-rotation pin 35 is located partly in the groove 17 and partly in the last machined surface 19 just outward from the groove 17 . Therefore, a part of the anti-rotation pin 35 protrudes from the base of the groove 17 .

One or more deflector pins 63 fit in holes in the roller bit leg 13 and protrude forward, each deflector pin 63 having an axis parallel to the support pin axis 23 (FIG. 1). The front end of the deflector pin 63 is flat, and the space between it and the outer back portion 61 of the cone is small. The deflector pin 63 is used to divert cuttings and drilling fluid from the space between the back surface of the roller cone 37 and the adjacent surface of the roller cone bit palm 13 . The deflector pin 63 can also be omitted if desired. Also, the outer back portion 61 may extend in a straight line from the annular rib 59 to the scale surface 65, rather than being concave as shown.

In operation, each cone 37 rotates about the support pin axis 23 as the drill bit 11 rotates. Drilling fluid is pumped down the drill string, exits the nozzles, and returns around the exterior of the drill bit 11 along with cuttings. Seal 53 normally rotates synchronously with cone 37 and slidably engages the outer surface of blade ring cylindrical portion 27 . Due to the gravitational force applied to the drill bit 11 , the cone 37 oscillates or moves slightly relative to the axis of the support pin 15 . The blade ring 25 tends to rotate with the cone 37 , thereby floating relative to the axis of the support pin 15 . This floating motion helps maintain the desired contact pressure between the outer seal 53 and the floating blade ring 25 .

If used, the deflector pin 63 can reduce the amount of chips and debris that would otherwise enter the space between the last machined surface 19 and the back portions 57 and 61 . However some chips and debris will still contact the blade ring 25 . The blade ring 25 is preferably formed of a metal that is more resistant to wear and corrosion than the material of the roller cone bit leg 13, bearing pin 15, and roller cone 37, to prevent the galling typically present at the intersection between the last machined surface 19 and the bearing pin 15 .

The present invention has clear advantages. The blade ring reduces the contact pressure differential applied to the seal. The blade ring also provides protection against the seal from chips and debris.

While the invention has been shown in only one form thereof, it will be apparent to those skilled in the art that the invention is not limited thereto and various changes may be made therein without departing from the scope of the invention.

Claims (20)

1. stratum bore bit comprises:

Drill main body, this drill main body has the hanger bearing pin, limits a basal region at the joint of drill main body and fulcrum post;

Be installed in the rigid blade ring on the fulcrum post, insert ring has the internal diameter greater than the fulcrum post external diameter, thereby limits a gap between insert ring and fulcrum post, to allow insert ring unsteady with respect to fulcrum post;

Inner seal liner, this inner seal liner and fulcrum post and insert ring internal diameter sealed engagement;

Be rotatably installed in the gear wheel on the fulcrum post, described gear wheel has the cavity that contains outer seal groove;

Be positioned at the outside seal may of outer seal groove, this outside seal may engages with the dynamic seal (packing) of insert ring external diameter; With

Prevent the anti-rotation element of insert ring rotation.

2. drill bit as claimed in claim 1, wherein, insert ring has uniform thickness around its periphery.

3. drill bit as claimed in claim 1, wherein, anti-rotation element is outstanding from basal region, and has the axis perpendicular to the joint ring part of its joint.

4. drill bit as claimed in claim 1, wherein, anti-rotation element comprises the pin of the pit that engages insert ring.

5. drill bit as claimed in claim 1, wherein,

Basal region comprises cylindrical surface on the fulcrum post and the adjacent last machining surface on the main body;

Insert ring has the radially extending flange of the described last machining surface of butt; And

Anti-rotation element comprises from the outstanding pin of described last machining surface, and the pit in the flange of this outstanding pin and insert ring engages.

6. drill bit as claimed in claim 1, wherein,

Basal region comprises cylindrical surface on the fulcrum post and the adjacent flat surface on the main body; Wherein drill bit also comprises:

Annular groove on the described flat surfaces; With

Flange on the insert ring is recessed in the annular groove this flange portion.

7. drill bit as claimed in claim 6, wherein,

Gear wheel has the annular back face around the mouth of cavity, and this annular back face has outstanding circular rib, and described circular rib extends on the part of flange outside diameter.

8. drill bit as claimed in claim 1, wherein,

Insert ring has radially extending flange;

Outer seal groove has parallel side wall, and one of them sidewall defines the circular rib of the gear wheel between flange and outer seal ring.

9. drill bit as claimed in claim 1, wherein, inner seal liner comprises:

Be formed on the interior sealed groove on the fulcrum post;

Elastomeric ring in the interior sealed groove, this elastomeric ring and insert ring internal diameter sealed engagement.

10. stratum bore bit comprises:

Drill main body, this drill main body has the bit leg that has the hanger bearing pin, limits a basal region at the joint of bit leg and fulcrum post;

Be installed in the rigid blade ring on the fulcrum post, insert ring has the internal diameter greater than the fulcrum post external diameter, thereby limits a gap between insert ring and fulcrum post, to allow insert ring unsteady with respect to fulcrum post;

Be formed on the interior sealed groove on the fulcrum post;

Elastic body inner seal ring in the interior sealed groove, this elastic body inner seal ring and insert ring internal diameter sealed engagement;

Gear wheel with cavity, this gear wheel is rotatably installed on the fulcrum post;

Be arranged in the outside seal may of cavity, this outside seal may and gear wheel and insert ring external diameter sealed engagement; With

Be installed to the pin linear element on the basal region, this pin linear element projects to the part of insert ring and engages, to prevent the insert ring rotation.

11. drill bit as claimed in claim 10, wherein, insert ring and inner seal liner have homogeneous thickness around its periphery.

12. drill bit as claimed in claim 10, wherein,

Basal region comprises cylindrical surface on the fulcrum post and the adjacent last machining surface on the main body;

Insert ring has the radially extending flange of the described last machining surface of butt; And

The pin linear element is outstanding from described last machining surface, engages with pit in the flange of insert ring.

13. drill bit as claimed in claim 10, wherein, outside seal may comprises:

Be formed on the outer seal groove in the cavity; With

Be positioned at the elastic body outer seal ring of outer seal groove inside.

14. drill bit as claimed in claim 13, wherein,

Insert ring has radially extending flange;

Outer seal groove has two parallel side walls, and described sidewall defines the circular rib of the gear wheel between flange and outer seal ring.

15. drill bit as claimed in claim 10, wherein,

Basal region comprises cylindrical surface on the fulcrum post and the adjacent flat surface on the main body; Wherein drill bit also comprises:

Annular groove on the described flat surfaces; With

Flange on the insert ring is recessed in the annular groove this flange portion.

16. drill bit as claimed in claim 15, wherein,

Gear wheel has the annular back face around the mouth of cavity, and this back side has outstanding circular rib, and described circular rib extends on the part of flange outside diameter.

17. a stratum bore bit comprises:

Drill main body, this drill main body has the bit leg that has the hanger bearing pin;

The rigid blade ring, this rigid blade ring has the flange portion and the cylindrical part of the part of butt bit leg, cylindrical part has the internal diameter greater than the fulcrum post external diameter, thereby between the cylindrical part of insert ring and fulcrum post, limit a gap, to allow insert ring unsteady with respect to fulcrum post;

Be formed on the interior sealed groove on the fulcrum post;

Elastic body inner seal ring in the interior sealed groove, the cylindrical part sealed engagement of this elastic body inner seal ring and insert ring;

Gear wheel with cavity, this gear wheel is rotatably installed on the fulcrum post;

Be formed on the outer seal groove in the cavity, this outer seal groove has parallel side wall;

The elastic body outer seal ring, the cylindrical part sealed engagement of this elastic body outer seal ring and outer seal groove and insert ring, one of them sidewall of outer seal groove separates the flange of outer seal ring with insert ring; With

Be installed to the pin linear element on the part of drill main body, this pin linear element projects to the part of insert ring and engages, to prevent the insert ring rotation.

18. drill bit as claimed in claim 17, wherein, insert ring and inner seal ring have homogeneous thickness around its periphery.

19. drill bit as claimed in claim 17, wherein,

Flange portion on the insert ring partly is recessed in the annular groove that forms on the bit leg.

20. drill bit as claimed in claim 19, wherein: gear wheel has the back side around the mouth of cavity, and this back side has outstanding circular rib, and described circular rib partly extends on the flange portion external diameter of insert ring.

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