A rotatable composite sheet for PDC drill bits

Abstract

This invention relates to the field of drilling tool technology, specifically to a rotatable composite blade for PDC drill bits, comprising a fixed base and a cutting section. The fixed base has a rotating hole at its front end, and a rotating shaft is coaxially mounted at the rear end of the cutting section. The rotating shaft is rotatably positioned within the rotating hole, with a rotational clearance between the rotating hole and the rotating shaft. A rotating assembly is disposed within the rotational clearance to limit axial displacement between the rotating shaft and the rotating hole. This invention addresses the problem in existing technologies where PDC composite blades are mostly fixed structures, making it impossible to rotate the cutting surface. This results in extremely low overall utilization of the composite blade, requiring frequent tripping and bit replacement, which not only prolongs the drilling cycle but also significantly increases drilling operation costs.

Description

Technical Field

[0001] This invention relates to the field of drilling tool technology, and more specifically to a rotatable composite sheet for PDC drill bits. Background Technology

[0002] PDC drill bits, with their high rock-breaking performance, have become the mainstream drilling tool in oil and gas exploration, geological drilling, and other fields. The PDC composite blade, as its core cutting component, directly determines the drilling efficiency and service life of the drill bit. In complex formations with high abrasiveness and high ground stress, the cutting surface of the PDC composite blade experiences rapid wear and fracture only in the localized area in contact with the rock, while the remaining areas remain intact. This localized failure results in extremely low overall utilization of the composite blade, requiring frequent tripping and bit replacement, which not only prolongs the drilling cycle but also significantly increases drilling operation costs. Existing PDC composite blades are mostly fixed structures, unable to achieve rotating use of the cutting surface, making it difficult to solve the core problem of localized wear. Therefore, there is an urgent need for a composite blade structure that allows rotation and uniform wear of the cutting surface. Summary of the Invention

[0003] The purpose of this invention is to provide a rotatable composite sheet for PDC drill bits, which solves the problem that in the prior art, most PDC composite sheets are fixed structures, which cannot achieve the rotation of cutting surfaces, resulting in extremely low overall utilization of the composite sheet and the need for frequent tripping up and down of the drill bit to replace the drill bit. This not only prolongs the drilling cycle but also significantly increases the drilling operation cost.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A rotatable composite disc for PDC drill bits includes a fixed base and a cutting part. The front end of the fixed base is provided with a rotating hole, and the rear end of the cutting part is coaxially provided with a rotating shaft. The rotating shaft is rotatably disposed in the rotating hole, and a rotating gap is left between the rotating hole and the rotating shaft. A rotating assembly is disposed in the rotating gap, and the rotating assembly is used to limit the axial displacement between the rotating shaft and the rotating hole.

[0006] A further technical solution is that the outer wall of the rotating shaft is set as a first conical surface, the diameter of the first conical surface gradually decreases from back to front, the hole wall of the rotating hole is set as a second conical surface, the taper of the second conical surface matches the taper of the first conical surface, and the opposite sides of the rotating assembly slide against the first conical surface and the second conical surface respectively.

[0007] A further technical solution is that the rotating assembly includes several needle rollers, which are arranged along the length of the rotating shaft and surround the rotating shaft within the rotation gap.

[0008] A further technical solution is that the wall of the rotating hole is recessed along the hole direction of the rotating hole, and several rotating grooves are provided along the wall of the rotating hole, with several needle rollers respectively rotating and disposed in the rotating grooves.

[0009] A further technical solution is that the front end of the fixed base is recessed around the rotating hole with an adjustment ring groove, and a limit block is set in the adjustment ring groove. The front end of the cutting part is provided with a polycrystalline diamond layer. Several through holes penetrating both sides are provided around the cutting part near the edge. A limit rod is set in the through hole. The rear end of the limit rod is placed in the adjustment ring groove. The front end of the limit rod is provided with a fragile section, and the front end of the fragile section abuts against the rear side of the polycrystalline diamond layer. The adjustment ring groove is recessed on one side of the limit block with a first spring groove. A spring piece is provided at the opening of the first spring groove. One end of the spring piece is connected to the opening of the first spring groove on the side away from the limit block, and the other end abuts against the limit block. A spring is provided in the first spring groove. The front end of the spring abuts against the rear side of the spring piece, and the rear end of the spring abuts against the bottom of the first spring groove. A second spring groove is provided at the rear end of the rotating shaft. A torsion spring is provided in the second spring groove. The front end of the torsion spring is connected to the groove wall of the second spring groove. An end cap is provided at the rear end of the fixed base, and the rear end of the torsion spring is connected to the end cap.

[0010] A further technical solution is that the groove wall of the second spring groove is recessed along the axial direction of the rotation shaft and a slot is provided. The front end of the torsion spring is locked in the slot. A stop bar is provided at the front end of the end cover. The rear end of the torsion spring abuts against the stop bar. A knob groove is provided at the rear end of the end cover. The end cover is welded and fixed to the fixed base.

[0011] A further technical solution is that the rotating component includes a conical steel ball fixing frame, which is sleeved on the outer wall of the rotating shaft. The thickness of the steel ball fixing frame is less than the spacing of the rotation gap. The steel ball fixing frame is provided with several mounting holes that pass through both sides. A first steel ball is placed in the mounting hole. The two sides of the first steel ball protrude from the opposite sides of the mounting hole and roll in contact with the first conical surface and the second conical surface.

[0012] A further technical solution is that the steel ball fixing frame is composed of multiple first tiles spliced ​​together.

[0013] A further technical solution is that the rotating component includes several second steel balls, which are evenly distributed within the rotation gap.

[0014] A further technical solution is that the rotating component includes several second tiles, which are spliced ​​together in a cone shape and set in the rotation gap.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. During drilling, the cutting part adaptively rotates around the axis with the rock-breaking cutting force, so that the cutting surface is worn evenly, which greatly improves the overall utilization rate of the composite piece, extends its service life by 30%-50%, reduces the number of tripping in and out of the hole, and reduces drilling costs. It is suitable for high-efficiency drilling operations in highly abrasive and complex formations; 2. By setting a rotating component, the smoothness of rotation between the rotating hole and the rotating shaft can be improved. Attached Figure Description

[0016] Figure 1 This is a side cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiments 1 and 2 of the present invention.

[0017] Figure 2 This is a cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiments 1 and 2 of the present invention.

[0018] Figure 3 This is a side cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 3 of the present invention.

[0019] Figure 4 This is a cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 3 of the present invention.

[0020] Figure 5 This is a side cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 5 of the present invention.

[0021] Figure 6 This is a cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 5 of the present invention.

[0022] Figure 7 This is a side cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 4 of the present invention.

[0023] Figure 8 This is a schematic diagram of the front end of a fixing base for a rotatable composite sheet for a PDC drill bit in Embodiment 4 of the present invention.

[0024] Figure 9 for Figure 7 A cross-sectional view of point A from another perspective.

[0025] Figure 10 This is a side cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 6 of the present invention.

[0026] Figure 11 This is a cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 6 of the present invention.

[0027] Figure 12This is a cross-sectional schematic diagram of a rotatable composite sheet for PDC drill bits in Embodiment 7 of the present invention.

[0028] Icons: 1-Fixed base, 2-Cutting part, 3-Rotating hole, 4-Rotating shaft, 5-First conical surface, 6-Second conical surface, 7-Adjusting ring groove, 8-Limiting block, 9-Polycrystalline diamond layer, 10-Through hole, 11-Limiting rod, 12-Fragile section, 13-First spring groove, 14-Spring piece, 15-Second spring groove, 16-Torsion spring, 17-End cap, 18-Card slot, 19-Stop bar, 20-Steel ball fixing bracket, 21-Mounting hole, 22-First steel ball, 23-First tile, 24-Second steel ball, 25-Second tile, 26-Needle roller, 27-Rotating groove, 28-Rotating clearance, 29-Spring, 30-Knob groove. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1:

[0031] like Figures 1 to 12 As shown, a rotatable composite sheet for PDC drill bits includes a fixed base 1 and a cutting section 2. The front end of the fixed base 1 has a rotating hole 3, and the rear end of the cutting section 2 is coaxially mounted with a rotating shaft 4. The rotating shaft 4 is rotatably positioned within the rotating hole 3, and a rotating clearance 28 is provided between the rotating hole 3 and the rotating shaft 4. A rotating assembly is disposed within the rotating clearance 28 to limit the axial displacement between the rotating shaft 4 and the rotating hole 3. During drilling, the cutting section 2 adaptively rotates axially with the rock-breaking cutting force, resulting in uniform wear of the cutting surface. This significantly improves the overall utilization rate of the composite sheet, extends its service life by 30%-50%, reduces the number of tripping operations, and lowers drilling costs. It is suitable for high-efficiency drilling operations in highly abrasive and complex formations. The rotating assembly improves the smoothness of rotation between the rotating hole 3 and the rotating shaft 4. During assembly, the composite sheet is welded and fixed to the PDC drill bit body via the fixed base 1.

[0032] The outer wall of the rotating shaft 4 is configured as a first conical surface 5, with the diameter of the first conical surface 5 gradually decreasing from back to front. The wall of the rotating hole 3 is configured as a second conical surface 6, and the taper of the second conical surface 6 matches the taper of the first conical surface 5. The opposite sides of the rotating assembly slide against the first conical surface 5 and the second conical surface 6, respectively. With the cooperation of the first conical surface 5 and the second conical surface 6, when there is a rotating assembly between the first conical surface 5 and the second conical surface 6 and the rotation gap 28, the rotating shaft 4 is restricted from moving forward axially. This prevents the cutting part 2 from separating from the fixed base 1 during use, while ensuring that the cutting part 2 can rotate between the fixed base 1 and the fixed base 1.

[0033] Example 2:

[0034] like Figure 1 and Figure 2 As shown, the rotating assembly includes a plurality of needle rollers 26, which are arranged along the length of the rotating shaft 4 and surround the rotating shaft 4 within the rotating gap 28. In this embodiment, the needle rollers 26 replace the first steel ball 22 and the steel ball fixing frame 20, serving to assist rotation and limit axial displacement.

[0035] Example 3:

[0036] like Figure 3 and Figure 4 As shown, a rotating groove 27 is recessed along the hole wall of the rotating hole 3, and several rotating grooves 27 are provided along the hole wall of the rotating hole 3. Several needle rollers 26 are respectively rotatably disposed in the rotating grooves 27. In this embodiment, the position of the needle rollers 26 is restricted by adding rotating grooves 27 to prevent the needle rollers 26 from tilting during use.

[0037] Example 4:

[0038] like Figure 7 , Figure 8 and Figure 9As shown, the front end of the fixed base 1 is recessed around the rotating hole 3 with an adjusting ring groove 7. A limit block 8 is provided in the adjusting ring groove 7. The front end of the cutting part 2 is provided with a polycrystalline diamond layer 9. Several through holes 10 extending through both sides are provided around the cutting part 2 near the edge. A limit rod 11 is provided in the through holes 10. The rear end of the limit rod 11 is placed in the adjusting ring groove 7. The front end of the limit rod 11 is provided with a fragile section 12. The front end of the fragile section 12 abuts against the rear side of the polycrystalline diamond layer 9. The adjusting ring groove 7 is recessed on one side of the limit block 8 with a first spring groove 13. The groove is provided with a spring piece 14. One end of the spring piece 14 is connected to the groove of the first spring groove 13 on the side away from the limiting block 8, and the other end abuts against the limiting block 8. A spring 29 is provided in the first spring groove 13. The front end of the spring 29 abuts against the rear side of the spring piece 14, and the rear end of the spring 29 abuts against the bottom of the first spring groove 13. A second spring groove 15 is provided at the rear end of the rotating shaft 4. A torsion spring 16 is provided in the second spring groove 15. The front end of the torsion spring 16 is connected to the groove wall of the second spring groove 15. An end cap 17 is provided at the rear end of the fixed base 1. The rear end of the torsion spring 16 is connected to the end cap 17. During operation, the PDC drill bit rotates at high speed. Due to differences in cutting positions and PDC models, the composite discs at different locations may rotate autonomously or fail to rotate effectively during drilling. Therefore, this embodiment adds an auxiliary rotation structure to control the composite disc's automatic rotation after wear at the rock contact point, ensuring the unworn portion remains in contact with the rock. Specifically, during drilling, the edge of the polycrystalline diamond layer 9 typically impacts the rock, breaking up the rock strata for drilling. Figure 3 and Figure 4 As shown, when installing the torsion spring 16, by rotating the torsion spring 16, a force is generated on the rotating shaft 4 as follows: Figure 4The force is clockwise as shown. When the polycrystalline diamond layer 9 is not worn, the limiting rod 11, under the thrust of the torsion spring 16, abuts against the limiting block 8, preventing the rotating shaft 4 from rotating. When the polycrystalline diamond layer 9 is worn, the through hole 10 is exposed, and the fragile segment 12, under the thrust of the spring 29 and the spring piece 14 in the first spring groove 13, is pushed out of the through hole 10 and impacts the rock. During the impact, the fragile segment 12 is quickly consumed, and the limiting rod 11 located at the position of the limiting block 8 is pushed to the front end of the limiting block 8. At this time, the limiting rod 11 can no longer cooperate with the limiting block 8 to restrict the rotation of the torsion spring 16, so the torsion spring 16 will push the rotating shaft 4 to rotate until the next limiting rod 11 is in contact with the limiting block 8. During the rotation of the rotating shaft 4, the next limiting rod 11 will be in contact with the front side of the spring piece 14 to squeeze the spring piece 14 and the spring 29, causing the spring piece 14 and the spring 29 to be compressed and reset. The fragile section 12 can be hollow, so that after it breaks, it can quickly create space that allows the limiting rod 11 to move forward. The fragile section 12 can be made of brittle plastic or other brittle materials. The cutting edge of the polycrystalline diamond layer 9 has a chamfered structure with a radius of C0.5-C1.5mm.

[0039] The second spring groove 15 has a recessed groove 18 along the axial direction of the rotation shaft 4. The front end of the torsion spring 16 is engaged in the groove 18. The front end of the end cover 17 has a stop bar 19, and the rear end of the torsion spring 16 abuts against the stop bar 19. The rear end of the end cover 17 has a knob groove 30, and the end cover 17 is welded to the fixing base 1. By providing the groove 18, the front end of the torsion spring 16 can be engaged in the groove 18 when installing the torsion spring 16, and the front end of the torsion spring 16 can be pushed into the second spring groove 15. An end cap 17 groove is provided at the rear end of the fixed base 1 for installing the end cap 17. The bottom of the end cap 17 groove is connected to the rotating hole 3. By providing a knob groove 30 and a stop bar 19, the end cap 17 can be placed into the end cap 17 groove during installation. After fixing the fixed base 1, a tool is inserted into the knob groove 30 to rotate the end cap 17. During rotation, the stop bar 19 abuts against the rear end of the torsion spring 16, and as the end cap 17 rotates, it drives the torsion spring 16 to rotate, applying a certain number of rotations, thereby facilitating the generation of elastic potential energy in the torsion spring 16. After the rotating groove is rotated into place, the end cap 17 and the end cap 17 groove are fixed by welding.

[0040] Example 5:

[0041] like Figure 5 and Figure 6As shown, the rotating assembly includes a conical steel ball holder 20, which is sleeved on the outer wall of the rotating shaft 4. The thickness of the steel ball holder 20 is less than the spacing of the rotation gap 28. The steel ball holder 20 has several through-holes 21 on both sides. A first steel ball 22 is placed in each of the through-holes 21. The two sides of the first steel ball 22 protrude from the opposite sides of the through-holes 21 and roll in contact with the first conical surface 5 and the second conical surface 6. In this embodiment, the steel ball holder 20 and the first steel ball 22 are designed to facilitate rotation between the rotating shaft 4 and the rotating hole 3, while the first steel ball 22 restricts axial displacement between the rotating hole 3 and the rotating shaft 4.

[0042] The steel ball fixing bracket 20 is composed of multiple first tiles 23 spliced ​​together. Each first tile 23 is provided with several mounting holes 21. This arrangement allows the first steel ball 22 to be placed into the mounting holes 21 and then the first tile 23 to be pushed into the rotation gap 28 when installing the steel ball fixing bracket 20, improving the ease of installation and avoiding the problem that if the steel ball fixing bracket 20 is installed as a whole, a large number of first steel balls 22 may not be effectively fixed, making installation difficult.

[0043] Example 6:

[0044] like Figure 10 , Figure 11 As shown, the rotating assembly includes several second steel balls 24, which are evenly distributed within the rotation gap 28. In this embodiment, the second steel balls 24 are used to replace the first steel balls 22 and the steel ball fixing bracket 20, which facilitates the control of rotation between the rotating shaft 4 and the rotating hole 3. At the same time, the second steel balls 24 can restrict axial displacement between the rotating hole 3 and the rotating shaft 4.

[0045] Example 7:

[0046] like Figure 12 As shown, the rotating assembly includes several second tiles 25, which are spliced ​​together in a conical shape and disposed within the rotation gap 28. In this embodiment, the second tiles 25 replace the first steel ball 22 and the steel ball fixing frame 20, serving to assist rotation and limit axial displacement.

[0047] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A rotatable composite sheet for PDC drill bits, characterized in that, The device includes a fixed base (1) and a cutting part (2). The front end of the fixed base (1) is provided with a rotating hole (3), and the rear end of the cutting part (2) is coaxially provided with a rotating shaft (4). The rotating shaft (4) is rotatably disposed in the rotating hole (3), and a rotating clearance (28) is left between the rotating hole (3) and the rotating shaft (4). A rotating assembly is provided in the rotating clearance (28), and the rotating assembly is used to limit the axial displacement between the rotating shaft (4) and the rotating hole (3). The front end of the fixed base (1) surrounds the rotating hole (3). The cutting part (2) is provided with an adjustment ring groove (7) and a limit block (8) is provided in the adjustment ring groove (7). A polycrystalline diamond layer (9) is provided at the front end of the cutting part (2). Several through holes (10) are provided around the cutting part (2) near the edge, and a limit rod (11) is provided in the through hole (10). The rear end of the limit rod (11) is placed in the adjustment ring groove (7). The front end of the limit rod (11) is provided with a fragile section (12). The front end of the fragile section (12) abuts against the rear side of the polycrystalline diamond layer (9). Next, the adjusting ring groove (7) is recessed on one side of the limiting block (8) with a first spring groove (13). A spring piece (14) is provided at the opening of the first spring groove (13). One end of the spring piece (14) is connected to the opening of the first spring groove (13) away from the limiting block (8), and the other end abuts against the limiting block (8). A spring (29) is provided in the first spring groove (13). The front end of the spring (29) abuts against the rear side of the spring piece (14), and the rear end of the spring (29) is connected to the bottom of the first spring groove (13). The rotating shaft (4) is provided with a second spring groove (15) at its rear end. A torsion spring (16) is provided in the second spring groove (15). When the polycrystalline diamond layer (9) is not worn, the limiting rod (11) abuts against the limiting block (8) under the thrust of the torsion spring (16), so that the rotating shaft (4) will not rotate. The front end of the torsion spring (16) is connected to the groove wall of the second spring groove (15). The fixed base (1) is provided with an end cap (17) at its rear end. The rear end of the torsion spring (16) is connected to the end cap (17).

2. The rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The outer wall of the rotating shaft (4) is set as a first conical surface (5), the diameter of the first conical surface (5) gradually decreases from back to front, the hole wall of the rotating hole (3) is set as a second conical surface (6), the taper of the second conical surface (6) matches the taper of the first conical surface (5), and the opposite sides of the rotating assembly slide against the first conical surface (5) and the second conical surface (6) respectively.

3. A rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The rotating assembly includes a plurality of needle rollers (26), which are arranged along the length of the rotating shaft (4), and the plurality of needle rollers (26) are arranged around the rotating shaft (4) within the rotating gap (28).

4. A rotatable composite sheet for PDC drill bits according to claim 3, characterized in that: The rotating hole (3) has a recessed rotating groove (27) along the hole direction of the rotating hole (3). Several rotating grooves (27) are provided along the hole wall of the rotating hole (3), and several needle rollers (26) are respectively rotatably disposed in the rotating grooves (27).

5. A rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The second spring groove (15) has a groove (18) recessed along the axial direction of the rotating shaft (4). The front end of the torsion spring (16) is engaged in the groove (18). The front end of the end cover (17) is provided with a stop bar (19). The rear end of the torsion spring (16) abuts against the stop bar (19). The rear end of the end cover (17) is provided with a knob groove (30). The end cover (17) is welded and fixed to the fixed base (1).

6. A rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The rotating assembly includes a conical steel ball holder (20), which is sleeved on the outer wall of the rotating shaft (4). The thickness of the steel ball holder (20) is less than the spacing of the rotation gap (28). The steel ball holder (20) is provided with a plurality of mounting holes (21) that pass through both sides. A first steel ball (22) is provided in the mounting hole (21), and the two sides of the first steel ball (22) protrude from the opposite sides of the mounting hole (21).

7. A rotatable composite sheet for PDC drill bits according to claim 6, characterized in that: The steel ball fixing frame (20) is composed of multiple first tiles (23) spliced ​​together, and each first tile (23) is provided with several mounting holes (21).

8. A rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The rotating assembly includes a plurality of second steel balls (24), which are evenly distributed within the rotating gap (28).

9. A rotatable composite sheet for PDC drill bits according to claim 1, characterized in that: The rotating assembly includes several second tiles (25), which are spliced ​​together in a cone shape and disposed in the rotating gap (28).

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