US20190178037A1

US20190178037A1 - Sealing arrangement

Info

Publication number: US20190178037A1
Application number: US15/840,489
Authority: US
Inventors: Todd Bielawa
Original assignee: Century Products Inc
Current assignee: Century Products Inc
Priority date: 2017-12-13
Filing date: 2017-12-13
Publication date: 2019-06-13

Abstract

A cone arm assembly comprises an arm having a shaft extending therefrom in which the shaft is angularly surrounded by a shoulder surface on one end thereof. A cone has a recess formed therein which receives the shaft in a manner to permit a rotation of the cone relative to the shaft about a rotational axis. The cone has a base surface facing the shoulder surface of the arm. A first seal element is positioned within the recess and forms a first seal between the shaft of the arm and the cone. A second seal element is positioned within the recess and forms a second seal between the shaft of the arm and the cone. The second seal is positioned closer to the shoulder surface than the first seal. A third seal element forms a third seal between the base surface of the cone and the shoulder surface of the arm.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

BACKGROUND

The present disclosure relates generally, but is not limited, to hole openers for horizontal and vertical drilling through rock. In particular, this disclosure relates to a sealing arrangement that can be employed in a cone arm assembly that is coupled to a bit body of a hole opener or tri-cone bit.
Tri-cone bits and hole openers are commonly used to drill and bore through rock. To break apart rock, the tri-cone bits and hole openers typically have one or more cutting elements coupled to a rotating shaft. During operation, the shaft axially loads the cutting elements by forcing the cutting elements against the rock. The rotation of the shaft then causes the hardened surfaces of the cutting elements to break apart the rock.
Cone arm assemblies are a commonly used cutting element for this process. The cone arm assemblies have an arm and a cone that rotates relative to a shaft extending outward from the arm. A primary seal is placed between the shaft and the cone to retain lubrication within the cone and to prevent debris and moisture from entering the gaps between the shaft and cone and contacting bearings within the assembly.
Due to the abrasive nature of the materials (e.g., rock) being cut and the axial and radial loading and impacts experienced by the cone arm assembly during the cutting process, the primary seal is often subject to failure. The cone arm assembly is often submersed in gritty mud and bentonite mixtures, which suspend sharp rock and abrasive materials that can come into contact with and damage the shaft and seals of the cone arm assembly during cutting. Repeated use of the cone arm assembly can also result in material buildups (e.g., cuttings or debris) forming between the shaft and the cone. The material buildups within the cone arm assembly can cause grinding between the cone and arm during rotation, which produces high temperatures within the cone arm assembly. The high temperatures experienced within the cone arm assembly can damage the primary seal. Once the primary seal has been compromised, contaminants can contact and damage the bearings, which can eventually lead to cone arm assembly failure.
Cone arm assemblies are also subject to damage from the weather, as they are often left outside for extended periods of time, where rain, snow, dust, or other debris can contact and damage the primary seal within the cone arm assembly. As more debris and moisture passes beyond the primary seal, the bearings present upon the shaft may be damaged, which can result in cone arm assembly failure.
A need exists for an improved cone arm assembly that is able to withstand the harsh conditions experienced during rock drilling and boring processes for prolonged periods of time.

BRIEF SUMMARY

The present disclosure provides a cone arm assembly having a sealing arrangement that distributes and dissipates the loading experienced by the cone arm assembly during operation to prolong the life of the primary seal. The cone arm assembly restricts moisture and abrasive materials from contacting the primary seal.
In one embodiment, the present disclosure provides a cone arm assembly. The cone arm assembly comprises an arm having a shaft extending therefrom. The shaft is angularly surrounded by a shoulder surface on one end of the shaft. A cone has a recess formed therein that receives the shaft in a manner to permit a rotation of the cone relative to the shaft about a rotational axis. The cone has a base surface facing the shoulder surface of the arm. A first seal element is positioned within the recess, and forms a first seal between the shaft of the arm and the cone. A second seal element is positioned within the recess and forms a second seal between the shaft of the arm and the cone. The second seal element is positioned closer to the shoulder surface than the first seal element. A third seal element forms a third seal between the base surface of the cone and the shoulder surface of the arm.
In some embodiments, a groove extends inward from the base surface of the cone, which can receive the third seal element. The groove can comprise a first side wall, a second side wall, and a bottom wall. The first side wall, second side wall, and the bottom wall can collectively extend circumferentially about the base surface of the cone. In some embodiments, the recess is formed of a first cylindrical section and a second cylindrical section. The first cylindrical section can be defined by a first radius and can extend inwardly away from the base surface of the cone. The second cylindrical section can be defined by a second radius smaller than the first radius, and can extend inwardly away from the first cylindrical section. A first channel and a second channel can be formed within the first cylindrical section, and the first channel can receive a portion of the first seal element, while the second channel can receive a portion of the second seal element.
In some embodiments, at least one bearing is coupled to the shaft. The at least one bearing can be positioned distally away from the first seal element, the second seal element, and the third seal element. In some embodiments, the third seal element is positioned radially outward from the first seal element and the second seal element. The first seal element, second seal element, and third seal element can each be positioned concentric with the rotational axis, but at different axial positions with respect to one another.
These and still other advantages of the invention will be apparent from the detailed description and the drawings. What follows is merely a description of some preferred embodiments of the present invention. To assess the full scope of the invention, the claims should be looked to, as these preferred embodiments are not intended to be the only embodiments within the scope of the claims.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be better understood and features, aspects and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings.

FIG. 1 is a perspective view of a cone arm assembly according to one exemplary embodiment.

FIG. 2A is a cross-sectional view of the cone arm assembly of FIG. 1 taken along line 2A-2A.

FIG. 2B is a detail view of the cone arm assembly taken along arc 2B-2B of FIG. 2A.

Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the embodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 illustrates a cone arm assembly 10 for drilling and boring through earth and rock. The cone arm assembly 10 includes an arm 12 and a cone 14 that can rotate about the arm 12. A plurality of teeth 16 can be positioned about the cone. The teeth 16 can be formed of a hardened material, like tungsten carbide. In some embodiments, the teeth 16 are tungsten carbide inserts removably coupled to the cone 14.
With further reference now to FIGS. 2A and 2B, the internal structure of the cone arm assembly 10 is shown. The arm 12 has a mounting surface 18 that can be coupled to a bit body (not shown) of a hole cutter or a tri-cone bit. In some embodiments, the mounting surface 18 of the arm 12 can be coupled to a pocket (not shown) formed in the bit body using a key and slot interface, as shown and described in U.S. Pat. No. 7,845,437 B2, which is hereby incorporated by reference in its entirety. A plurality of threaded holes 20 can extend through the mounting surface 18 to receive fasteners or pins that can be used to couple the arm 12 to the bit body.
A shoulder surface 22 extends away from the mounting surface 18. In some embodiments, the shoulder surface 22 extends away from the mounting surface 18 to form a substantially flat surface. The shoulder surface 22 can be angularly offset from the mounting surface 18. In some embodiments, the offset between the mounting surface 18 and the shoulder surface 22 forms an obtuse angle (i.e., greater than 90 degrees) between the mounting surface 18 and the shoulder surface 22. A shaft 24 extends outwardly away from the shoulder surface 22 to define a rotational axis X-X. The shaft 24 can be generally cylindrical in shape.
The cone 14 is rotatably coupled to the shaft 24. The shaft 24 is received within a recess 26 formed in the cone 14. One or more bearings 28, 30, 32 can be positioned between the shaft 24 and the recess 26 formed in the cone 14 to enable precise rotation of the cone 14 on the shaft 24 and to reduce friction between the recess 26 and the shaft 24 as the cone 14 rotates. Seal elements 34, 36, 38 are positioned between the arm 12 and cone 14 to restrict abrasive materials, moisture, and other unwanted contaminants from entering into the recess 26 and contacting or damaging the bearings 28, 30, 32. In some embodiments, the first seal element 34, the second seal element 36, and the third seal element 38 can each be positioned concentric with the rotational axis X-X, but at different axial positions with respect to one another.
The first seal element 34 can be positioned within the recess 26 and can form a first seal between the shaft 24 and the cone 14. In some embodiments, the first seal element 34 is positioned axially between the bearing 32 and a base surface 40 of the cone 14. The first seal element 34 can act as a primary seal between the bearings 28, 30, 32 and rock, earth, or moisture that is present outside the cone arm assembly 10. The first seal created by the first seal element 34 can also retain lubrication present within the bearings 28, 30, 32 to extend bearing life. The first seal element 34 can be an o-ring, and can be formed of a resilient elastomeric material. For example, the first seal element 34 can be formed of a hydrogenated nitrile butadiene rubber (HNBR).
The second seal element 36 can also be positioned within the recess 26 and can form a second seal between the shaft 24 and the cone 14. The second seal element 36 can be positioned axially between the first seal element 34 and the base surface 40 of the cone 14. The second seal element 36 can form a secondary seal between the bearings 28, 30, 32 and abrasive materials or moisture external to the cone arm assembly 10. In some embodiments, the second seal element 36 acts as a radial dampener between the cone 14 and the arm 12. The second seal element 36 can dissipate energy within the cone arm assembly 10 that is created by cyclic loading during cutting or drilling processes. The second seal element 36 can also provide shock absorption to counter intermittent shock loads that may be experienced by the cone arm assembly 10. The second seal element 36 can also be formed of an elastomeric material, and can be an o-ring, quad-ring, or other type of dynamic rotary seal. In some embodiments, the second seal element 36 can be a PolyPak® seal having an o-ring used to energize a conventional lip-type seal.
The third seal element 38 can be positioned between the base surface 40 of the cone 14 and the shoulder surface 22 of the arm 12. The third seal element 38 can form a third seal between the shoulder surface 22 and the base surface 40 of the cone 14 that further restricts abrasive materials or unwanted moisture from contacting the bearings 28, 30, 32. Due to its placement between the shoulder surface 22 and the base surface 40 of the cone 14, the third seal element 38 can restrict unwanted contaminants from entering into the recess 26 of the cone 14 altogether. The third seal element 38 can be formed of a resilient elastomeric material, such as urethane, for example. In some embodiments, the third seal element 38 has a Shore A hardness exceeding 60. In some embodiments, the third seal element 38 can have a composite seal design incorporating an elastic static energizer element and a wear-resistant material on the dynamic sealing surfaces. A PolyPak® seal, for example, can also be used as the third seal element 38.
The third seal element 38 restricts the amount of contaminants and abrasive material that can enter into the recess 26, which can improve the life of the second seal element 36 and first seal element 34 respectively. The third seal element 38 also protects the second seal element 36 and the first seal element 34 when the cone arm assembly 10 is not performing a cutting or drilling process. In many scenarios, hole openers or tri-cone bits having cone arm assemblies 10 are stored outside and are exposed to the outdoor elements for extended periods of time. Rain, dust, dirt, and other unwanted contaminants may contact the cone arm assembly 10 before, during, and after use. The third seal element 38 can protect the recess 26 from these contaminants, which could otherwise cause recess 26 wall corrosion, shaft 24 corrosion, or bearing 28, 30, 32 corrosion if left in contact with the internal components of the cone arm assembly 10. By maintaining a seal between the shoulder surface 22 and the base surface 40 of the cone 14, rust or other corrosion that may prevent or restrict rotation of the cone 14 relative to the arm 12 is reduced. Correspondingly, the bearing 28, 30, 32 life, first seal element 34 life, second seal element 36 life, and overall cone arm assembly 10 life is improved.
The third seal element 38 also serves as a dampener that counteracts axial loading experienced by the cone arm assembly 10 during cutting or drilling processes. The resilient nature of the third seal element 38 provides additional protection to internal components (e.g., bearings 28, 30, 32) present within the recess 26 of the cone 14 that may otherwise be affected by sudden impacts or shock loading imparted on the cone 14. The third seal element 38 can also help restrict sudden contact that may occur between the base surface 40 and the shoulder surface 22. In some embodiments, the shoulder surface 22 and the base surface 40 are approximately parallel to one another, and the distance between the shoulder surface 22 and the base surface 40 is between about 0.038 cm (0.015 in) and about 0.064 cm (0.025 in). The cone 14 may deflect relative to the shaft 24 when it is axially loaded during cutting or drilling, and the base surface 40 may be biased toward the shoulder surface 22. The dampening properties of the third seal element 38 can dissipate the energy from the axial loading, reducing the impact (if any) that occurs between the base surface 40 and the shoulder surface 22. The third seal element 38 can extend upwardly from the base surface 40 of the cone 14 as well, so that contact occurs between the shoulder surface 22 and the third seal element 38 before contact can occur between the shoulder surface 22 and the base surface 40.
The shape of the shaft 24 can help locate the seal elements 34, 36, 38 and the bearings 28, 30, 32 within the cone arm assembly 10. In some embodiments, the shaft 24 has a tiered structure, and includes a first section 42 proximate to the shoulder surface 22 and a second section 44 extending outwardly away from the first section 42. The first section 42 can be defined by a radius R1 larger than a radius R2 defining the second section 44. A first annular surface 46 can be formed at the meeting of the first section 42 and the second section 44. A third section 48 can extend outwardly from the second section 44, and a second annular surface 50 can be formed at the meeting of the second section 44 and the third section 48. The third section 48 can be defined by a radius R3 smaller than the radius R2. In some embodiments, a distal section 52 extends outwardly from the third section 48. The distal section 52 can be defined by a radius R4 that is larger than the radius R3. A third annular surface 54 opposing the second annular surface 50 can be formed at the junction of the third section 48 and the distal section 52. In some embodiments, the radius R4 is smaller than the radius R2. A distal end 55 of the shaft 24 can be defined by the distal section 52.
In some embodiments, a plurality of grooves 56, 58 are formed in the shaft 24 to receive bearings 28, 30, 32. For example, a first bearing groove 56 can be formed in the first section 42. In some embodiments, the first bearing groove 56 has a semicircular cross-section and extends circumferentially around the shaft 24. In some embodiments, the first bearing groove 56 acts as a race for one or more ball bearings 30. A second bearing groove 58 can also be formed in the shaft 24. The second bearing groove 58 can be defined by a portion of the second annular surface 50, the outer surface of the third section 48, and the third annular surface 54. The second bearing groove 58 can also extend circumferentially around the shaft 24, and can support one or more roller bearings 28.
The shaft 24 is received within the recess 26 formed within the cone 14. The recess 26 extends inward from the base surface 40 of the cone 14 that faces the shoulder surface 22 of the arm 12. The recess 26 can form a clearance fit with the shaft 24, permitting the rotation of the cone 14 about the shaft 24. In some embodiments, the recess 26 is formed of a first cylindrical section 60 and a second cylindrical section 62. The first cylindrical section 60 can extend inwardly away from the base surface 40 and can be defined by a radius R5. The radius R5 can be larger than the radius R1, so that the first section 42 of the shaft 24 can form a clearance fit with the first cylindrical section 60 of the recess 26. A second cylindrical section 62 can extend inwardly away from the first cylindrical section 60, and can be defined by a radius R6 smaller than the radius R5. A step 64 can be formed at the junction between the first cylindrical section 60 and the second cylindrical section 62. The radius R6 can be larger than the radii R2, R3, and R4, so that the second section 44, the third section 48, and the distal section 52 can form a clearance fit with the second cylindrical section 62 of the recess 26. When the cone 14 is coupled to the arm 12, the first annular surface 46 can engage the step 64. A thrust washer 66 can be positioned between the first annular surface 46 and the step 64. In some embodiments, a lubrication reservoir 68 extends inwardly away from the second cylindrical section 62.
The recess 26 within the cone 14 can also be defined by one or more bearing grooves 70, 72 extending circumferentially around the recess 26. In some embodiments, a first bearing groove 70 is formed in the first cylindrical section 60. The first bearing groove 70 can have a semicircular cross-section that extends inwardly from the first cylindrical section 60. When the cone 14 is coupled to the shaft 24, the first bearing groove 70 can serve as the outer race for one or more ball bearings 30, and can be axially aligned with the first bearing groove 56 formed in the shaft 24. A second bearing groove 72 can be formed in the first cylindrical section 60 of the recess 26 as well. In some embodiments, the second bearing groove 72 has a rectangular cross-section, and can support one or more roller bearings 32. The second bearing groove 72 can be positioned axially between the base surface 40 and the first bearing groove 70.
In some embodiments, the cone 14 is coupled to the shaft 24 using the ball bearings 30. The ball bearings 30 can be introduced between the first bearing groove 56 formed in the shaft and first bearing groove 70 formed in the cone 14 using a bearing insertion hole 73, which extends through a portion of the arm 12 and the shaft 24. Once the ball bearings 30 are placed within the first bearing grooves 56, 70, the ball bearings 30 restrict relative axial motion between the shaft 24 and the cone 14, coupling the shaft 24 to the cone 14. The ball bearings 30 also promote rotational motion of the cone 14 about the shaft 24.
The recess is further defined by channels 74, 76 that receive seal elements 34, 36. A first channel 74 can be formed in the first cylindrical section 60. The first channel 74 can have a rectangular cross-section and can be positioned axially between the base surface 40 and the second bearing groove 72. The first channel 74 can be defined by an upper wall 78, a lower wall 80, and a radial wall 82 extending between the upper wall 78 and lower wall 80. The radial wall 82 can extend circumferentially about the cone 14. The radial wall 82 can be defined by a radius R7 that is larger than the radius R5 that defines the first cylindrical section 60. The first seal element 34 can be received within the first channel 74, where it forms a seal between the shaft 24 and the cone 14. In some embodiments, an adhesive can be used to couple the first seal element 34 to at least one of the upper wall 78, the lower wall 80, and the radial wall 82. In other embodiments, the upper wall 78, the lower wall 80, and the radial wall 82 compress the first seal element 34 to secure the first seal element 34 in place.
The second channel 76 can be positioned axially between the base surface 40 and the first channel 74. Like the first channel 74, the second channel 76 can also be defined by an upper wall 84, a lower wall 86, and a radial wall 88 extending between the upper wall 84 and the lower wall 86. The radial wall 88 can be defined by a radius R8 that is also larger than the radius R5, and can extend circumferentially about the cone 14. In some embodiments, the radius R8 is smaller than the radius R7. The second seal element 36 is received within the second channel 76, and forms a seal between the shaft 24 and the cone 14. The second seal element 36 can be coupled to the second channel 76. In some embodiments, the second seal element 36 is compressed by the upper wall 84 and lower wall 86 to maintain the second seal element 36 within the second channel 76. Adhesive can also be used to secure the second seal element 36 within the second channel 76.
A groove 90 can be formed in the base surface 40 of the cone 14 to receive the third seal element 38. The groove 90 can be defined by a first side wall 92, a second side wall 94, and a bottom wall 96. The first side wall 92, the second side wall 94, and the bottom wall 96 can extend circumferentially about the base surface 40. The third seal element 38 can be received within the groove 90, where it can then form the third seal between the base surface 40 and the shoulder surface 22. In some embodiments, the groove 90 can instead be formed in the shoulder surface 22 of the arm 12.
In some embodiments, the bottom wall 96 of the groove 90, the upper wall 78 of the first channel 74, and the upper wall 84 of the second channel 76 each lie in approximately parallel planes. For example, each of the bottom wall 96 of the groove 90, the upper wall 78 of the first channel 74, and the upper wall 84 of the second channel 76 form flat surfaces approximately perpendicular to the rotational axis X-X. In some embodiments, the bottom wall 96 of the groove 90 is formed at a first depth D1 from the base surface 40. The upper wall 84 of the second channel 76 can be formed at a second depth D2 from the base surface 40 that is greater than the first depth D1. In some embodiments, the first side wall 92 and the second side wall 94 are positioned radially outward from the radial wall 88 of the second channel 76. The third seal element 38 can then be positioned radially outward from the first seal element 34 and the second seal element 36.
Using the seal element 34, 36, 38 configurations described in detail above, the life of the cone arm assembly 10 can be extended. The three seal element configuration present in the cone arm assembly 10 protects the internal components of the cone arm assembly 10 from corrosion and contamination during both operation and idle periods. The sealing and dampening provided by the sealing arrangement better counteracts impact loading experienced during cutting and drilling processes that could otherwise cause cone arm assembly 10 failure.
It should be appreciated that various other modifications and variations to the preferred embodiments can be made within the spirit and scope of the invention. Therefore, the invention should not be limited to the described embodiments. To ascertain the full scope of the invention, the following claims should be referenced.

Claims

We claim:

1. A cone arm assembly comprising:

an arm having a shaft extending therefrom in which the shaft is angularly surrounded by a shoulder surface on one end thereof;

a cone having a recess formed therein which receives the shaft in a manner to permit a rotation of the cone relative to the shaft about a rotational axis, the cone having a base surface facing the shoulder surface of the arm;

a first seal element positioned within the recess forming a first seal between the shaft of the arm and the cone;

a second seal element positioned within the recess forming a second seal between the shaft of the arm and the cone, the second seal being positioned closer to the shoulder surface than the first seal; and

a third seal element forming a third seal between the base surface of the cone and the shoulder surface of the arm.

2. The cone arm assembly of claim 1, wherein a groove extends inward from the base surface, the third seal element being placed within the groove.

3. The cone arm assembly of claim 2, wherein the groove comprises a first side wall, a second side wall, and a bottom wall, and the first side wall, the second side wall, and the bottom wall collectively extend circumferentially about the base surface.

4. The cone arm assembly of claim 2, wherein the recess is formed of a first cylindrical section and a second cylindrical section, the first cylindrical section being defined by a first radius and extending inwardly away from the base surface, and the second cylindrical section defined by a second radius smaller than the first radius, the second cylindrical section extending away inwardly away from the first cylindrical section.

5. The cone arm assembly of claim 4, wherein a first channel and a second channel are formed within the first cylindrical section, the first channel receiving a portion of the first seal element and the second channel receiving a portion of the second seal element.

6. The cone arm assembly of claim 5, wherein the first channel and second channel each comprise an upper wall, a radial wall, and a lower wall.

7. The cone arm assembly of claim 6, wherein the bottom wall of the groove, the upper wall of the first channel, and the upper wall of the second channel lie in approximately parallel planes.

8. The cone arm assembly of claim 6, wherein the bottom wall of the groove is formed at a first depth from the base surface and the upper wall of the second channel is formed at a second depth from the base surface greater than the first depth.

9. The cone arm assembly of claim 6, wherein the first side wall and second side wall are each positioned radially outward from the radial wall of the second channel.

10. The cone arm assembly of claim 4, wherein a thrust washer is positioned on a step formed at the junction of the first cylindrical section and the second cylindrical section.

11. The cone arm assembly of claim 4, wherein the first seal element is adhesively coupled to the first channel.

12. The cone arm assembly of claim 1, wherein at least one bearing is coupled to the shaft, the at least one bearing being positioned distally away from the first seal element, the second seal element, and the third seal element.

13. The cone arm assembly of claim 1, wherein the third seal element is positioned radially outward from the first seal element and the second seal element.

14. The cone arm assembly of claim 1, wherein the first seal element, the second seal element, and third seal element are each positioned concentric with the rotational axis, but at different axial positions with respect to one another.

15. The cone arm assembly of claim 1, wherein the third seal element has a Shore A hardness exceeding 60.

16. The cone arm assembly of claim 1, wherein the third seal element comprises urethane.

17. The cone arm assembly of claim 1, wherein a plurality of cutting carbides are coupled to an outer surface of the cone.

18. The cone arm assembly of claim 1, wherein the base surface of the cone and the shoulder surface of the arm are spaced apart from one another by between about 0.038 cm and about 0.064 cm.

19. The cone arm assembly of claim 1, wherein the second seal element is a PolyPak™ seal.

20. The cone arm assembly of claim 1, wherein each of the first seal element, the second seal element, and the third seal element are comprised of an elastomeric material.