Earth auger rotary bit and method
By adopting a consistent leg and gear design on the rotary drill bit, combining angle and linear offset, the problem of rotary drill bit imbalance is solved, achieving balanced and efficient drilling effect.
Patent Information
- Application Number
- CN202380064489.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-09-16
- Filing Date
- 2023-09-15
- Publication Date
- 2025-04-25
AI Technical Summary
Existing rotary drills have structural imbalances due to inconsistent cutting wheel designs, resulting in additional loads and interference, affecting drilling efficiency and cost.
The consistent leg and gear design is adopted, combining angular offset and linear offset to ensure that the gear tools do not interfere with each other during rotation and achieve a balanced structure.
The balance of rotary drill bits is achieved, reducing additional load, improving drilling efficiency and reducing maintenance costs, while providing good cutting capabilities.
Smart Images
Figure CN119895113A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an earth boring bit for rotary drilling.
[0002] The present invention further relates to a method of forming a rotary drill bit.
[0003] The field of the invention is defined more particularly in the preambles of the independent claims. Background Art
[0004] In mines and other work sites, different types of rock drilling machines are used to drill out boreholes. In rotary drilling, a drilling tool including one or more drill pipes is connected to a rock drilling machine or unit and rotated by a rotary device. At the far end there is a rotary drill bit for cutting and crushing rock material. The rotary drill bit comprises a number of cutting teeth, which are rotatably arranged to the body of the rotary drill bit and comprise a number of cutting elements. Typically, all cutting teeth have different designs so that the cutting edges of adjacent cutting teeth do not collide when the teeth rotate. However, the use of cutting teeth with different designs results in an unbalanced structure. Attempts have been made to achieve a balanced rotary drill bit, but no suitable solution has been found. Therefore, the known solutions have shown some disadvantages. Summary of the invention
[0005] An object of the present invention is to provide a new and improved rotary drill bit and method of forming the same.
[0006] The rotary drill bit according to the invention is characterized by the features of the independent device claim.
[0007] The method according to the invention is characterized by the features of the independent method claim.
[0008] The idea of the disclosed solution is that the earth drill rotary drill bit comprises a drill bit body having a longitudinal drill bit axis and three consistent legs. Three consistent rolling cone cutters are rotatably mounted to the consistent legs of the drill bit body. The rolling cone is mounted to a bearing journal and is provided with an axis of rotation about which the rolling cone can rotate. The cone cutter has an angular offset between the axis of rotation and the drill bit axis, whereby the axis of rotation of the cone cutter does not intersect the drill bit axis. The cone cutter also has a linear offset, which defines the distance between the projection of the axis of rotation of the cone cutter and a line parallel to the mentioned projection and intersecting the drill bit axis. For all three cone cutters, the angular offset and the linear offset are consistent. The magnitude of the angular offset is 2-17°, and the magnitude of the linear offset is 1.6-18 mm. In addition, the diameter of the rotary drill bit is 6-16 inches (152.4-406.4 mm).
[0009] In other words, the disclosed solution uses a consistent structure and specially designed and relatively high offset values to provide a balanced structure and prevent interference between cutting elements on adjacent roller cutters.
[0010] An advantage of the disclosed solution is that the angular offset and the linear offset are carefully designed so that no collision occurs in a three-cone rotary drill bit even if the rotary drill bit has three identical legs and roller cutters.
[0011] The consistent characteristics adopted in the rotary drill bit are to achieve a balanced rotary drill bit, in which the rotating masses are balanced and no harmful centrifugal forces are generated. In this way, no additional loads directed to the structure of the drilling equipment occur. It has been noted that the balanced characteristics also have a positive impact on drilling efficiency and drilling costs.
[0012] Another advantage is that the disclosed structure is relatively simple and inexpensive to manufacture and maintain because of the consistent structure and because the number of rotating cutting teeth is reduced since the rotating cutting teeth are all similar.
[0013] The disclosed solution with high offset values allows the use of cutting elements that protrude sufficiently to provide good cutting capabilities for the rotary drill bit.
[0014] The three coincident cones have the same rotational speed during drilling, which is beneficial. When the legs and cones are not coincident, then each cone has a different rotational speed.
[0015] The cutting elements are arranged so that each row overlaps the adjacent row of cones, making the cutting arrangement effective. A combination of linear and angular offsets are used to place the journals on the legs. This arrangement allows all three cones to rotate freely without interfering with adjacent cones.
[0016] According to one embodiment, the disclosed rotary drill bit is specifically designed for drilling in softer ground or soil formations.
[0017] According to one embodiment, the cutting cones of the disclosed rotary drill bit are provided with positively protruding cutting elements, whereby the disclosed rotary drill bit can provide high penetration rates in softer formations and soil layers.
[0018] According to one embodiment, the mentioned values of the angular offset and the linear offset depend on the projection on the cutting element (shaft or tooth) on the cone. The higher the value of the projection, the greater the values of the angular offset and the linear offset within the mentioned range.
[0019] According to one embodiment, a disclosed three-cone rolling cutter drill bit has consistent characteristics, thereby balancing the three-cone rotary drill bit. The consistent characteristics mean that the three legs of the drill bit body are similar, the three roller cutters are similar, the offset of each roller cutter is similar, and the three roller cutters and the legs are evenly distributed on the rotary drill bit, that is, they have similar spacing between them. In addition, in a consistent roller cutter, the number of cutting elements is the same, the position and orientation of the cutting elements are the same, and the shape of the body of the roller cutter is also similar.
[0020] According to one embodiment, the roller cutter comprises a plurality of hard metal cutting elements inserted into and protruding from a tapered surface of the roller cutter. In other words, the insert is made of a different material than the basic body of the roller cutter.
[0021] According to one embodiment, the hard metal cutting element is a tungsten carbide tooth.
[0022] According to one embodiment, the hard metal cutting elements are press-fit into holes drilled in the tapered cutting cutter such that they partially protrude outwardly.
[0023] According to one embodiment, the toothing is provided with a circular cross section and has a toothing diameter TCIØ. The linear offset Lo can be dimensioned according to the following formula Lo≥0.4*TCIØ. Therefore, the linear offset Lo depends on the toothing diameter TCIØ. Furthermore, the angular offset Ao can be dimensioned based on the calculated linear offset Lo and according to the following formula Ao≥0.5*Lo. When the offset is dimensioned by means of these formulas, there is sufficient clearance between the teeth of adjacent cutting teeth. The formula provides a minimum offset, which means that the offset value can be larger if necessary. The mentioned formula has been developed based on tests and empirical studies.
[0024] According to one embodiment, the cross-sectional diameter of the insert tooth is 12-16 mm. Example of determining the offset: Drill bit diameter 9" The diameter of the toothing is 14 mm TCI Ø Linear offset Lo: 0.4*14=5.6 mm, the calculated linear offset Lo is within the recommended range of 1.6-18 mm Angular offset Ao: 0.5*5.6=2.3°, thus the calculated angular offset Ao is within the recommended range of 2-17°.
[0025] According to one embodiment, the roller cutter comprises a plurality of milled cutting teeth formed on and protruding from a conical surface of the roller cutter. In other words, the cutting element is a tooth that is milled on the cutting roller and has the same base material as the body of the cutting roller. However, the teeth may be coated or treated with different techniques, for example, to improve their wear resistance.
[0026] According to one embodiment, the cutting element is a tooth formed on the cutting tooth wheel, and each milling cutting tooth has a uniform tooth width Tw at the outer end of the tooth. The linear offset Lo can be specified according to the following formula Lo≥0.4*Tw. Therefore, the linear offset Lo depends on the tooth width Tw. In addition, the specification of the angular offset Ao can be determined based on the calculated linear offset Lo and according to the following formula Ao≥0.5*Lo. When the specification of the offset is determined by means of these formulas, there is sufficient clearance between the adjacent cutting teeth. The formula provides a minimum offset, which means that the offset value can be larger if necessary. The mentioned formula was developed based on testing and empirical research.
[0027] According to one embodiment, the width of the tooth is 12-16 mm. The width value is defined at the top of the tooth and represents the minimum width of the tooth.
[0028] According to one embodiment, the rolling cone cutter comprises a body made of a steel material, and an outer surface of the body is provided with at least one wear-resistant layer.
[0029] According to one embodiment, the body of the roller cutter has a carburized surface on the milling cutting element.
[0030] According to one embodiment, the body of the roller cutter has a coating made of a wear resistant material.
[0031] According to one embodiment, the rolling cone cutter is provided with flat surfaces between the cutting elements protruding from its outer surface. In other words, the rolling cone cutter does not have any grooves between the cutting elements. Since no grooves or intermeshing grooves are required, the structure can be more rigid compared to solutions where grooves need to be provided to avoid collision of the cutting edges of adjacent rolling cone cutters. In solutions where the cutting elements are made of slotted teeth, there is more supporting base material surrounding the slotted teeth, thereby providing proper support for the slotted teeth.
[0032] According to one embodiment, the disclosed solution is used for rotary drilling, wherein no percussion equipment is used during the drilling process.
[0033] According to one embodiment, the disclosed solution relates to a method of forming a rotary drill bit for an earth drill. The method comprises: providing an elongated drill bit body having a longitudinal drill bit axis; providing a drill bit body having three consistent legs; rotatably mounting three consistent rolling cone cutters to the three legs; arranging the rolling cone cutters to be rotatable about the rotation axis; providing the cone cutters with an angular offset between the rotation axis and the drill bit axis so that the rotation axis of the cone cutters does not intersect the drill bit axis; and providing the cone cutters with a linear offset, the linear offset defining the distance between a projection of the rotation axis of the cone cutters and a line parallel to the mentioned projection and intersecting the drill bit axis. The method further comprises: applying a consistent angular offset and a linear offset to all of the three cone cutters; determining the magnitude of the angular offset to be 2-17° and the magnitude of the linear offset to be 1.6-18 mm; and using a rotary drill bit having a diameter of 6-16 inches (152.4-406.4 mm).
[0034] The above disclosed embodiments may be combined to form a suitable solution having desired ones of the above features. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Some embodiments are described in more detail in the accompanying drawings, in which
[0036] Figure 1 is a schematic side view of a ground drilling rig intended for rotary drilling,
[0037] Figure 2 is a schematic side view of a rotary drill bit of an earth auger,
[0038] Figure 3 is a schematic diagram of a rotating drill head viewed in the longitudinal direction and from one side at the bottom of a borehole,
[0039] Figure 4 is a schematic diagram showing how the cutting elements of the three roller cutters mesh with each other.
[0040] Figure 5 is a schematic side view of a roller cutter having a flat surface disposed between the cutting elements,
[0041] Figure 6 It is a schematic diagram of the bearing journal of the toothed tool.
[0042] Figure 7 It is a schematic diagram of the intermeshing cutting teeth of adjacent tooth wheel cutters.
[0043] Figure 8 is a schematic side view of a leg of a rotary drill bit provided with a roller cutter,
[0044] Fig. 9 is a schematic diagram of the intermeshing cutting teeth of adjacent tooth-wheel cutters.
[0045] Fig.10 is a schematic diagram of a rotary drill bit provided with milling teeth and viewed in the longitudinal direction and from one side at the bottom of a drill hole,
[0046] Fig.11 is a schematic side view of a three-cone rotary drill bit provided with machined cutting teeth, and
[0047] Fig.12 is a schematic diagram showing how the cutting teeth of adjacent roller cutters mesh with each other.
[0048] For the sake of clarity, the drawings show some embodiments of the disclosed solution in a simplified manner. In the drawings, the same reference numerals represent the same elements. DETAILED DESCRIPTION
[0049] Figure 1 A rock drilling rig 1 for ground drilling is shown. The rock drilling rig 1 comprises a movable carrier 2 and at least one drilling mast 3 connected to the carrier 2. The mast 3 is provided with a drilling unit 4 provided with a rotary head 5 supported on the mast 3 and movable in a drilling direction A and a return direction B by means of a feeding device 6. The rotary head 5 is connected to a drilling tool 7 by means of a subassembly 8. For the sake of clarity, the drilling tool 7 is shown in a simplified manner. The drilling tool 7 comprises one or more tubular elongated drill pipe assemblies and a rotary drill bit 9 at its distal end. The rotary drill bit 9 is typically 6-16 inches in diameter. The rotary head 5 rotates the drilling tool 7 about its longitudinal axis R and the drilling tool 7 is simultaneously fed towards the rock surface being drilled. This is known as a rotary drilling method. Drill cuttings are flushed by feeding a flushing fluid from a flushing system Fs via the drilling tool 7 to the borehole 10 being drilled so that the drill cuttings are flushed out of the borehole 10. The drilling unit 4 may be hydraulic, whereby it may be connected to a hydraulic system Hs.
[0050] Figure 2A rotary drill bit 9 is disclosed, comprising a drill bit body 11 having a longitudinal drill bit axis BA and three consistent legs 12. Three consistent rolling cone cutters 13 are rotatably mounted to the legs 12 and are provided with a rotation axis RA or bearing axis. The cone cutters 13 comprise a number of cutting elements 14, in this case hard metal cutting element splines 15, which are inserted into a conical surface of the cone cutters 13. The splines 15 protrude from the conical surface. The cone cutters 13 are consistent and mounted to the legs 12 in a similar manner. There may or may not also be additional cutting splines mounted on the radial surface of the legs 12. In order to perform flushing, one or more flushing openings 16 are arranged on the body 11. Furthermore, at the second end of the body 11 there is a connecting portion 17, which is used to mount the rotary drill bit 9 to a drill pipe. The connecting portion 17 typically comprises a connecting thread.
[0051] Figure 3 A rotary drill bit 9 is disclosed, which is provided with three consistent roller cutters 13, which are arranged so that the hard metal cutting teeth 15 of the roller cutters do not collide when the roller cutters 13 rotate due to the rotation of the entire rotary drill bit 9. The roller cutters 13 rotate around a rotation axis RA, which does not intersect the drill bit axis BA, and the entire rotary drill bit 9 rotates around the drill bit axis BA during drilling. Therefore, the roller cutters 13 have an angular offset Ao between the rotation axis RA and the drill bit axis BA. In addition, the roller cutters 13 have a linear offset Lo, which defines the distance between the projection of the rotation axis RA of the roller cutters 3 and a line parallel to the projection and intersecting the drill bit axis BA. The angular offset Ao and the linear offset Lo are consistent for all three roller cutters 13 and their sizes are within the ranges given in this document.
[0052] Figure 4 It is shown that when the roller cutter 13 is arranged according to the features disclosed in this document, the plungers 15 do not collide.
[0053] Figure 5 It is shown that no grooves are required between the cutting teeth 15 of the roller cutter 13. This is because the roller cutter 13 is based on the previous Figure 3 and Figure 4 The surface 18 between the prongs 15 can be flat.
[0054] Figure 6 A bearing arrangement or bearing journal 19 having an axis of rotation RA is disclosed. The roller cutter can be mounted on the bearing journal 19 and can rotate freely.
[0055] Figure 7Two cutting inserts 15 of two adjacent roller cutters are shown and how they are positioned relative to each other when the mentioned angular and linear offsets are met. The heads of the insert teeth 15 overlap and there is an offset in the transverse direction. There is a gap between the flank surfaces.
[0056] Figure 8 A leg 12 is disclosed which is provided with a roller cutter 13 comprising a number of cutting elements 14 .
[0057] Figure 9-12 An embodiment is disclosed in which all three roller cutters 13 are identical and provided with milling teeth 20. The teeth 20 have Fig. 9 The tooth width Tw disclosed in the document. The roller cutter 13 is oriented according to the features disclosed in this document, whereby the angular offset Ao and the linear offset Lo appear within the disclosed range. Since the main features correspond to Figures 2 to 4 The structures disclosed in the drawings are not described in detail and therefore these features do not need to be described in detail.
[0058] The drawings and the related description are intended only to illustrate the idea of the invention. The invention may vary in its details within the scope of the claims.
Claims
1. A soil drill rotary drill bit (9), comprising: a drill body (11) having a longitudinal drill axis (BA) and three coincident legs (12); three identical rolling cone cutters (13) rotatably mounted to the leg (11) and provided with a rotation axis (RA); The roller cutter (13) has an angular offset (Ao) between the rotation axis (RA) and the drill bit axis (BA), whereby the rotation axis (RA) of the roller cutter (13) does not intersect the drill bit axis (BA); and The roller cutter (13) has a linear offset (Lo), which defines the distance between a projection of the rotation axis (RA) of the roller cutter (13) and a line parallel to the projection and intersecting the drill bit axis (BA); It is characterized in that The angular offset (Ao) and the linear offset (Lo) are consistent for all three roller cutters (13); And wherein the magnitude of the angular offset (Ao) is 2-17°, and the magnitude of the linear offset (Lo) is 1.6-18 mm; And wherein the diameter (D) of the rotary drill bit (9) is 6-16 inches (152.4-406.4 mm).
2. The rotary drill bit according to claim 1, characterized in that: The roller cutter (13) comprises a plurality of hard metal cutting element teeth (15) which are inserted into and protrude from a tapered surface of the roller cutter (13).
3. The rotary drill bit according to claim 2, characterized in that: The insert (15) is provided with a circular cross section and has an insert diameter (TCI Ø) And wherein the linear offset (Lo) is specified according to the following formula: Lo ≥ 0.4*TCI Ø; And wherein the specification of the angular offset (Ao) is determined based on the calculated linear offset (Lo) and according to the following formula: Ao≥0.5*Lo.
4. The rotary drill bit according to claim 1, characterized in that: The roller cutter (13) comprises a plurality of milling cutting teeth (20) which are formed on a conical surface of the roller cutter (13) and protrude from the conical surface.
5. The rotary drill bit according to claim 4, characterized in that: Each of the milling cutting teeth (20) has a uniform tooth width (Tw) at an outer end of the tooth (20); And wherein the linear offset (Lo) is specified according to the following formula: Lo ≥ 0.4*Tw; And wherein the specification of the angular offset (Ao) is determined based on the calculated linear offset (Lo) and according to the following formula: Ao≥0.5*Lo.
6. The rotary drill bit according to any one of claims 1 to 5, characterized in that: The rolling cone cutter (13) comprises a main body made of steel material, and the outer surface of the main body is provided with at least one wear-resistant layer.
7. The rotary drill bit according to any one of claims 1 to 6, characterized in that The rolling cone cutter (13) is provided with a flat surface (18) between cutting elements (14) protruding from its outer surface.
8. A method of forming a rotary drill bit (9) for an earth boring machine, the method comprising: Providing an elongated drill bit body (11) having a longitudinal drill bit axis (BA); Providing the drill body (11) with three identical legs (12); rotatably mounting three identical rolling cone cutters (13) to the three legs (12); Arranging the rolling cone cutter (13) to be rotatable about a rotation axis (RA); The roller cutter (13) is arranged so that the roller cutter (13) has an angular offset (Ao) between the rotation axis (RA) and the drill bit axis (BA), so that the rotation axis (RA) of the roller cutter (13) does not intersect the drill bit axis (BA); as well as The roller cutter (13) is arranged so that the roller cutter (13) has a linear offset (Lo), the linear offset (Lo) defining the distance between a projection of the rotation axis (RA) of the roller cutter (13) and a line parallel to the projection and intersecting the drill bit axis (BA); The features include: Implementing consistent angular offset (Ao) and linear offset (Lo) for all three roller cutters (13); The specification of the angular offset (Ao) is determined to be 2-17°, and the specification of the linear offset (Lo) is determined to be 1.6-18 mm; And a rotary drill bit (9) having a diameter (D) of 6-16 inches (152.4-406.4 mm) is used.