All-metal cam-type screw impact drill and application thereof

Abstract

The application provides a full-metal cam screw impact drill and application thereof, wherein the screw impact drill comprises a bypass valve, a drop prevention unit, a motor unit, a flexible shaft unit and an impact unit connected in sequence, the impact unit comprises a shell, a cam stator in the shell, a cam rotor and a drill bit joint; the cam stator is fixedly connected with the shell, and the cam rotor is fixedly connected with the drill bit joint; the upper end surface of the cam rotor and the lower end surface of the cam stator are in abutment; the upper end surface of the cam rotor and the lower end surface of the cam stator are respectively provided with a first protrusion and a second protrusion; the cam rotor and the drill bit joint can rotate under the driving of the flexible shaft unit and make the first protrusion and the second protrusion produce periodic relative sliding, so that the cam rotor drives the drill bit joint to produce axial reciprocating motion. The application adopts full-metal materials, is resistant to high temperature and high pressure, and is resistant to impact and wear, and the rock breaking efficiency and application range can be improved by adjusting the size of the cam mechanism to adjust the impact amplitude and frequency.

Description

Technical Field

[0001] This invention relates to the field of downhole tools technology for oil and gas field development, and more specifically, to an all-metal cam-type screw impact drill and its application. Background Technology

[0002] As the field of oil and gas drilling and production technology continues to develop, it faces the challenge of harsh drilling conditions such as deep wells and hard formations. The technical problems of poor drillability caused by the characteristics of high temperature, high environmental pressure, high rock confining pressure and high rock hardness at the bottom of oil wells are becoming increasingly prominent. If conventional drilling machinery is used for drilling and production, ordinary deep drilling suffers from problems such as low mechanical drilling speed and severe drill bit wear, which can no longer effectively meet engineering requirements. To solve the above technical problems, Chinese patent document "Overload-Proof Screw Drill Tool" with publication number "CN107489381A" discloses an overload-proof screw drill tool that can cope with overload conditions. It includes a bypass valve assembly, a motor assembly, a universal joint assembly, and a drive shaft assembly. These four components are connected in sequence from top to bottom by threads to form a screw drill tool. An overload-proof component is also provided between the universal joint assembly and the drive shaft assembly. When the screw drill tool is overloaded, if the torque transmitted from the drive shaft to the drive short section is too large and exceeds the set value, the pressure provided by the disc spring assembly is insufficient to maintain the contact state of the toothed structure of the spline short section and the drive short section. The toothed structure of the drive short section and the toothed structure of the spline short section will separate axially, avoiding excessive motor pressure drop caused by excessive torque and damage to the motor assembly. However, it still cannot avoid the problems of drill bit wear and screw component fatigue failure when encountering stuck drill bit or high pressure environment at the bottom of the well. Therefore, it is necessary to propose a new technical solution to this technical problem. Summary of the Invention

[0003] The purpose of this invention is to overcome at least one of the aforementioned shortcomings of the prior art. For example, one objective of this invention is to provide an all-metal cam-type screw impact drill and its application.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] This invention provides an all-metal cam-type screw impact drill, comprising a bypass valve, an anti-drop unit, a motor unit, a flexible shaft unit, and an impact unit connected sequentially from top to bottom. The impact unit includes an impact unit housing, a cam mechanism, and a drill bit connector. The cam mechanism includes a cam stator and a cam rotor arranged sequentially from top to bottom within the cavity of the impact unit housing. The cam stator is fixedly connected to the impact unit housing, and the cam rotor is fixedly connected to the drill bit connector. The upper end face of the cam rotor and the lower end face of the cam stator face each other and are always in contact. The lower end face of the cam stator and the upper end face of the cam rotor are respectively provided with a plurality of first protrusions and a plurality of second protrusions. The cam rotor and the drill bit connector can rotate circumferentially under the drive of the flexible shaft unit. During the circumferential rotation, periodic relative sliding occurs between the first and second protrusions, thereby causing the cam rotor to drive the drill bit connector to simultaneously generate axial reciprocating motion.

[0006] Alternatively, when there is more than one first protrusion, it can be non-uniformly arranged circumferentially on the lower end face of the cam stator, and when there is more than one second protrusion, it can be non-uniformly arranged circumferentially on the upper end face of the cam rotor.

[0007] Optionally, the bypass valve may include a valve body, a valve seat, a valve sleeve, a spring, and a retaining ring. The valve body has a first side hole on its side wall, and the valve seat has a through hole. The lower end of the valve body passes through the through hole. The two ends of the spring are respectively abutted against the valve body and the valve seat. The valve body can move along the axis of the valve seat towards the valve seat under the pressure of the drilling fluid and compress the spring. The valve sleeve is sleeved outside the valve body and the valve seat. The valve sleeve has several second side holes on its side wall. The drilling fluid can flow out of the bypass valve through the first side hole and the second side hole. The retaining ring is installed on the inner wall of the valve sleeve. The lower end of the valve seat abuts against the upper end of the retaining ring. The retaining ring can fix the valve seat axially.

[0008] Alternatively, the anti-drop unit may include an anti-drop plug, an anti-drop sub, and an anti-drop housing. The upper end of the anti-drop sub is fixedly connected to the anti-drop plug. Both the anti-drop plug and the anti-drop sub are inserted into the anti-drop housing. A gap is left between the outer wall of the anti-drop plug and the anti-drop sub and the inner wall of the anti-drop housing to allow drilling fluid to pass through.

[0009] Alternatively, the motor unit may include a motor stator and a motor rotor, with the motor rotor passing through the motor stator and capable of rotating about an axis under the drive of drilling fluid.

[0010] Alternatively, the outer wall of the motor rotor may be provided with several spiral fluid passage grooves, and a fluid passage hole may be provided at the lower end, so that drilling fluid can flow along the fluid passage grooves through the outer wall of the motor rotor and reach the lower end of the motor rotor along the fluid passage hole.

[0011] Alternatively, the flexible shaft unit may include a flexible shaft, a drive shaft, and a flexible shaft housing. The lower end of the flexible shaft is fixedly connected to the upper end of the drive shaft. The flexible shaft housing is sleeved outside the flexible shaft and the drive shaft. The flexible shaft and the drive shaft can rotate around an axis under the drive of the motor unit.

[0012] Alternatively, the impact drill bit may further include a sealing body and a sealing gasket, which are disposed between the motor unit and the flexible shaft unit. The lower end of the sealing body abuts against the upper end of the sealing gasket, and the sealing body and sealing gasket can prevent drilling fluid from passing through the gap between the flexible shaft and the flexible shaft housing.

[0013] Alternatively, the flexible shaft unit may further include a bearing, which is sleeved between the flexible shaft housing and the drive shaft, and the bearing can fix the drive shaft in the radial direction.

[0014] Alternatively, a drive key may be provided between the drive shaft and the drill bit connector, which can circumferentially fix the drive shaft and the drill bit connector.

[0015] Alternatively, the flexible shaft, the drive shaft, and the drill bit joint may each have a central hole that extends vertically through the center. The upper end of the central hole is connected to the fluid passage hole, allowing the drilling fluid to flow along the fluid passage hole and the central hole to the bottom of the drill bit joint.

[0016] Alternatively, the impact unit may further include an adapter sleeved on the lower end of the drill bit connector and connected to the housing of the impact unit.

[0017] Another aspect of the present invention provides an application of the all-metal cam-type screw impact drill as described above in rock breaking.

[0018] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0019] 1. This invention provides an all-metal cam-type screw impact drill, which eliminates the use of rubber materials, resulting in a longer tool life, the ability to withstand higher temperatures and pressures, and better resistance to impact and wear.

[0020] 2. This invention can adjust the impact amplitude and frequency, improve rock breaking efficiency, and to a certain extent increase the applicability of the tool.

[0021] 3. In order to improve the periodic variation of the impact, an axial motion mechanism consisting of a cam stator and a cam rotor is set up, which enables the downhole axial movement to be realized in a purely mechanical structure, reduces the complexity of the structure itself, avoids the use of an electronic control mechanism, and does not require additional energy consumption.

[0022] 4. To improve the impact effect within the cycle and make the impact have different degrees of intensity, thereby improving the rock breaking efficiency, the spacing is set differently so that it can achieve rock breaking with different forces within the cycle, thereby improving the rock breaking effect and protecting the drill bit, avoiding the continuous superposition of the same force; at the same time, the axial motion mechanism is also set with different sizes so that it can be replaced according to different strata and lithologies.

[0023] 5. The provided cam stator and cam rotor are both detachably connected, and the internal protrusions are also detachably connected. They are available in various sizes to facilitate replacement with various required sizes. Furthermore, after the contact surface is worn, it can be directly reprocessed into the next size without the need for complete scrapping, thus improving the recycling rate. Attached Figure Description

[0024] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 A cross-sectional view of an all-metal cam-type screw impact drill according to an exemplary embodiment 1 of the present invention is shown.

[0026] Figure 2 A cross-sectional view of the impact unit in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0027] Figure 3 A perspective view of the cam stator in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0028] Figure 4 A perspective view of the cam rotor in an all-metal cam-type screw impact drill according to Exemplary Example 1 of the present invention is shown.

[0029] Figure 5 This diagram illustrates the engagement of the cam stator and cam rotor in one state of an all-metal cam-type screw impact drill according to Exemplary Embodiment 1 of the present invention.

[0030] Figure 6 This diagram illustrates another state of the engagement between the cam stator and cam rotor in the all-metal cam-type screw impact drill of Exemplary Embodiment 1 of the present invention.

[0031] Figure 7 A cross-sectional view of the bypass valve in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0032] Figure 8 A cross-sectional view of the anti-drop unit in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0033] Figure 9A perspective view of the motor rotor in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0034] Figure 10 A cross-sectional view of the flexible shaft unit in an all-metal cam-type screw impact drill according to an exemplary embodiment 1 of the present invention is shown.

[0035] Figure 11 It shows Figure 1 Enlarged view of section I in the middle.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1-Bypass valve, 11-Valve body, 111-First side hole, 12-Valve sleeve, 121-Second side hole, 13-Valve seat, 14-Spring, 15-Retaining ring;

[0038] 2-Anti-drop unit, 21-Anti-drop plug, 22-Anti-drop short section, 23-Anti-drop housing;

[0039] 3-Motor unit, 31-Motor stator, 32-Motor rotor, 321-Liquid passage, 322-Liquid passage hole;

[0040] 4-Flexible shaft unit, 41-Flexible shaft, 42-Drive shaft, 43-Flexible shaft housing, 44-Drive key, 45-Bearing;

[0041] 5-Impact unit, 51-Cam mechanism, 511-Cam stator, 512-Cam rotor, 513-First protrusion, 514-Second protrusion, 52-Drill bit connector, 53-Impact unit housing;

[0042] 6-Sealing body, 7-Sealing gasket. Detailed Implementation

[0043] In the following description, an all-metal cam-type screw impact drill and its application will be explained in detail with reference to exemplary embodiments.

[0044] It should be noted that terms such as "first," "second," "third," and "fourth" are used merely for ease of description and distinction, and should not be construed as indicating or implying relative importance. Similarly, terms such as "upper," "lower," "inner," "outer," "front," "back," "left," and "right" are used merely for ease of description and to establish relative orientations or positional relationships, and do not indicate or imply that the referred component must possess that specific orientation or position. For those skilled in the art, some terms in this document, such as "pressure," are equivalent to pressure intensity.

[0045] Exemplary Example 1

[0046] This exemplary embodiment provides an all-metal cam-type screw impact drill.

[0047] Figure 1 A cross-sectional view of an all-metal cam-type screw impact drill bit according to exemplary embodiment 1 of the present invention is shown. Figure 2 A cross-sectional view of the impact unit in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown. Figure 3 A perspective view of the cam stator in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown. Figure 4 A perspective view of the cam rotor in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown. Figure 5 This diagram illustrates the engagement of the cam stator and cam rotor in one state of an all-metal cam-type screw impact drill bit according to Exemplary Embodiment 1 of the present invention. Figure 6 This diagram illustrates another state of the engagement between the cam stator and cam rotor in the all-metal cam-type screw impact drill of Exemplary Embodiment 1 of the present invention.

[0048] like Figures 1 to 6 As shown, the all-metal cam-type screw impact drill includes a bypass valve 1, an anti-drop unit 2, a motor unit 3, a flexible shaft unit 4, and an impact unit 5, which are fixedly connected from top to bottom.

[0049] In this embodiment, the lower end of the bypass valve 1 is connected to the upper end of the anti-drop unit 2 by internal and external threads, the lower end of the anti-drop unit 2 is connected to the upper end of the motor unit 3 by internal and external threads, the lower end of the motor unit 3 is connected to the upper end of the flexible shaft unit 4 by internal and external threads, and the lower end of the flexible shaft unit 4 is connected to the upper end of the impact unit 5 by internal and external threads and a key. However, the present invention is not limited to this. Other detachable connection methods besides threaded and keyed connections, such as expansion joints, can also be used for the connection methods at the above locations.

[0050] Further, the impact unit 5 includes an impact unit housing 53, a cam mechanism 51, and a drill bit connector 52. In this embodiment, the impact unit housing 53 is sleeved outside the cam mechanism 51 and the drill bit connector 52. The cam mechanism 51 includes a cam stator 511 and a cam rotor 512 arranged sequentially from top to bottom in the cavity of the impact unit housing 53. The cam stator 511 is connected to the impact unit housing 53 by countersunk bolts, so that the cam stator 511 and the impact unit housing 53 are relatively fixed. The cam rotor 512 is connected to the drill bit connector 52 by countersunk bolts, so that the cam rotor 512 and the drill bit connector 52 are relatively fixed. However, the present invention is not limited to this. In addition to countersunk bolts, the connection between the cam stator 511 and the impact unit housing 53 can also be made by threads or expansion joints on the outer wall of the cam stator 511 and the inner wall of the impact unit housing 53, or other detachable connection methods. In addition to countersunk bolts, the connection between the cam rotor 512 and the drill bit connector 52 can also be made by welding, riveting, snap-fit ​​connection, or other fixed connection methods.

[0051] Furthermore, the center of the cam stator 511 and the cam rotor 512 are respectively provided with holes for drilling fluid to flow through. The upper end face of the cam rotor 512 and the lower end face of the cam stator 511 face each other and can always abut against each other under the upward pressure of the formation on the drill bit joint 52 along the axial direction. In this embodiment, six first protrusions 513 are detachably connected to the lower end face of the cam stator 511 by bolts. These six first protrusions 513 are non-uniformly distributed along the circumference of the cam stator 511. The upper end face of the cam rotor 512 is detachably connected to six second protrusions 514 by bolts. These six second protrusions 514 are non-uniformly distributed along the circumference of the cam rotor 512. However, the present invention is not limited to this. The number of first protrusions 513 and second protrusions 514 can also be a positive integer greater than or equal to 1 other than 6. The first protrusions 513 and second protrusions 514 are respectively connected to... In addition to bolt connection, the connection between the cam stator 511 and the cam rotor 512 can also be a slide rail and groove fit or a snap-fit ​​connection or other detachable connection methods. The first protrusion 513 and the second protrusion 514 can also be evenly distributed along the circumference of the cam stator 511 and the cam rotor 512, respectively. That is to say, the distance between two adjacent first protrusions 513 on the cam stator 511 is adjustable, and the distance between two adjacent second protrusions 514 on the cam rotor 512 is also adjustable. This can generate different rock breaking forces within the cycle to adapt to different types of downhole working conditions.

[0052] Furthermore, the cam rotor 512 and drill bit joint 52 can rotate circumferentially under the drive of the flexible shaft unit 4, while the cam stator 511 and impact unit housing 53 remain fixed. Therefore, relative circumferential rotation occurs between the cam rotor 512 and the cam stator 511. During this circumferential rotation, the first protrusion 513 and the second protrusion 514 can respectively undergo periodic relative sliding and contact and collision under the drive of the cam stator 511 and the cam rotor 512, thereby causing a periodic change in the axial distance between the cam rotor 512 and the cam stator 511 (e.g., ...). Figure 5 and Figure 6 The diagram shows two engagement states between the cam rotor and the cam stator. In other words, when the cam stator 511 and the impact unit housing 53 remain fixed, the cam rotor 512 can drive the drill bit connector 52 to generate axial periodic reciprocating motion, which further causes the drill bit connected to the end of the drill bit connector 52 to generate axial reciprocating impact during drilling, thereby achieving the rock-breaking effect of the drill bit on the formation.

[0053] Furthermore, an adapter may be fitted onto the lower end of the drill bit connector 52, and the upper end of the adapter may be connected to the impact unit housing 53 by a thread. However, the present invention is not limited to this, and the adapter and the impact unit housing 53 may be connected in other ways besides the threaded connection.

[0054] Figure 7 A cross-sectional view of the bypass valve in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0055] like Figure 1 and Figure 7 As shown, the bypass valve 1 is located at the uppermost end of the all-metal cam-type screw impact drill, and includes a valve body 11, a valve sleeve 12, a valve seat 13, a spring 14, and a retaining ring 15. The two ends of the spring 14 are respectively abutted against the lower end of the valve body 11 and the upper end of the valve seat 13. The valve sleeve 12 is sleeved outside the valve body 11 and the valve seat 13. The valve seat 13 and the valve sleeve 12 are relatively fixed. The valve body 11 can move in the valve sleeve 12 along the axis of the valve sleeve 12 under the action of external force. When the valve body 11 moves toward the valve seat 13, it can compress the spring 14.

[0056] In this embodiment, the valve sleeve 12 has a central hole that runs vertically through it. The valve body 11, valve seat 13, and spring 14 are all inserted through the central hole of the valve sleeve 12. The inner wall of the valve sleeve 12 has a step. The upper end of the valve body 11 can abut against the step to prevent the valve body 11 from moving further upward along the axial direction of the valve sleeve 12. That is, after the valve body 11 abuts against the step, it is located at the uppermost end of its travel. The inner wall of the valve sleeve 12 also has an annular groove. The retaining ring 15 is installed in the annular groove and fixed. The lower end of the valve seat 13 abuts against the upper end of the retaining ring 15 to achieve axial fixation of the valve seat 13.

[0057] Furthermore, the valve seat 13 has a through hole extending vertically. The through hole is divided into an upper section and a lower section. The diameter of the lower section is larger than that of the upper section. The radial dimension of the lower end of the valve body 11 matches the diameter of the upper section of the through hole in the valve seat 13. The lower end of the valve body 11 can extend into the through hole of the valve seat 13. A blind hole is provided axially at the center of the valve body 11. The blind hole can communicate with the central hole of the valve sleeve 12. A through first side hole 111 is provided radially on the side wall of the valve body 11. The two ends of the first side hole 111 are respectively connected to the inner and outer walls of the valve body 11. That is, the two ends of the first side hole 111 are respectively connected to the blind hole of the valve body 11 and the central hole of the valve sleeve 12 below the valve body 11. In this embodiment, there are 4 first side holes 111, but the present invention is not limited to this. The number of first side holes 111 can also be any positive integer greater than or equal to 1 other than 4.

[0058] Furthermore, a radially penetrating second side hole 121 is provided on the side wall of the valve sleeve 12. The axial position of the second side hole 121 on the valve sleeve 12 is located between the valve body 11 and the valve seat 13. The two ends of the second side hole 121 are respectively connected to the inner and outer walls of the valve sleeve 12. That is, the two ends of the second side hole 121 are respectively connected to the central hole of the valve sleeve 12 and the outside of the valve sleeve 12. In this embodiment, there are two second side holes 121, but the present invention is not limited to this. The number of second side holes 121 can also be any positive integer greater than or equal to 1 other than 2.

[0059] Furthermore, at least one sealing ring is installed on the outer wall of both the valve body 11 and the valve seat 13, which can further improve the sealing performance between the valve body 11 and the valve sleeve 12, and between the valve seat 13 and the valve sleeve 12. In this embodiment, the number of sealing rings is two, and the material of the sealing rings is metal, which can improve the impact and wear resistance of the sealing rings to increase their service life. However, the present invention is not limited to this, and the number of sealing rings can also be any positive integer greater than or equal to 1 other than 2.

[0060] The working process of bypass valve 1 is described in detail below:

[0061] After the drilling fluid is injected into the central hole of the valve sleeve 12, when the downward axial pressure exerted by the drilling fluid on the valve body 11 is less than the upward elastic force exerted by the spring 14 on the valve body 11, the axial position of the valve body 11 remains fixed, and the drilling fluid can enter the blind hole of the valve body 11 along the central hole of the valve sleeve 12, and flow out to the outside of the valve sleeve 12 along the first side hole 111 and the second side hole 121. As the drilling fluid flow rate continues to increase, causing the downward axial pressure exerted by the drilling fluid on the valve body 11 to exceed the upward elastic force exerted by the spring 14 on the valve body 11, the valve body 11 begins to compress the spring and moves towards the valve seat 13. When the axial position of the first side hole 111 is located in the upper section of the through hole of the valve seat 13, the first side hole 111 is blocked by the inner wall of the valve seat 13. At this time, the drilling fluid cannot be discharged from the valve sleeve 12 through the first side hole 111 and the second side hole 121. As the valve body 11 continues to move downward under the axial pressure of the drilling fluid, when the first side hole 111 leaves the upper section of the through hole of the valve seat 13 and enters the lower section of the through hole, there is a gap between the first side hole 111 and the inner wall of the valve seat 13 that allows the drilling fluid to flow. The drilling fluid can then enter the lower part of the valve seat 13 along the first side hole 111 and continue to flow downward along the central hole of the valve sleeve 12.

[0062] When the flow rate of drilling fluid decreases until the downward pressure exerted by the drilling fluid on the valve body 11 is less than the upward elastic force exerted by the spring 14 on the valve body 11, the valve body 11 begins to move upward away from the valve seat 13. When the axial position of the first side hole 111 leaves the lower section of the through hole of the valve seat 13 and is located in the upper section of the through hole of the valve seat 13, the first side hole 111 is blocked by the inner wall of the valve seat 13. At this time, the drilling fluid cannot enter the lower part of the valve seat 13 through the first side hole 111. When the axial position of the first side hole 111 leaves the through hole of the valve seat 13 and is located above the valve seat 13, the drilling fluid can flow out along the first side hole 111 and the second side hole 121 to the outside of the valve sleeve 12.

[0063] Figure 8 A cross-sectional view of the anti-drop unit in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0064] like Figure 1 , Figure 7 and Figure 8 As shown, the anti-drop unit 2 includes an anti-drop plug 21, an anti-drop short section 22, and an anti-drop housing 23. In this embodiment, the anti-drop housing 23 is sleeved outside the anti-drop plug 21 and the anti-drop short section 22. The upper end of the anti-drop housing 23 is fixedly connected to the lower end of the valve sleeve 12 by threads, and the upper end of the anti-drop short section 22 is fixedly connected to the anti-drop plug 21 by threads. However, the present invention is not limited to this. The connection method between the anti-drop housing 23 and the valve sleeve 12, and the connection method between the anti-drop short section 22 and the anti-drop plug 21, can also be other fixed connection methods besides threaded connection.

[0065] Furthermore, the inner diameter of the anti-dumping housing 23 is larger than the outer diameter of the anti-dumping plug 21 and the anti-dumping stub 22. In other words, there is a gap between the inner wall of the anti-dumping housing 23 and the outer walls of the anti-dumping plug 21 and the anti-dumping stub 22 for drilling fluid to flow through. When the drilling fluid flows through the bypass valve 1 and enters the area below the valve seat 13, it can continue to flow downward along the gap between the inner wall of the anti-dumping housing 23 and the outer walls of the anti-dumping plug 21 and the anti-dumping stub 22.

[0066] Figure 9 A perspective view of the motor rotor in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown.

[0067] like Figure 1 , Figure 8 and Figure 9As shown, the motor unit 3 includes a motor stator 31 and a motor rotor 32. The motor stator 31 is sleeved on the outside of the motor rotor 32, and the motor rotor 32 can rotate circumferentially within the motor stator 31. In this embodiment, the upper end of the motor rotor 32 is fixedly connected to the lower end of the anti-drop section 22 by threads, and the upper end of the motor stator 31 is fixedly connected to the lower end of the anti-drop housing 23 by threads. However, the present invention is not limited to this, and the connection method between the motor rotor 32 and the anti-drop section 22, and the connection method between the motor stator 31 and the anti-drop housing 23, can also be other fixed connection methods besides threaded connection.

[0068] Furthermore, a spiral fluid passage groove 321 is provided on the outer wall of the motor rotor 32, and a step is formed at the lower end of the motor rotor 32. A fluid passage hole 322 corresponding to the fluid passage groove 321 is provided at the lower end of the step. Drilling fluid can flow from the upper end of the motor rotor 32 to the lower end of the motor rotor 32 along the fluid passage groove 321 and the fluid passage hole 322. In this embodiment, there are 5 fluid passage grooves 321 and 5 fluid passage holes 322. However, the present invention is not limited to this. The number of fluid passage grooves 321 and 5 fluid passage holes 322 can also be any positive integer greater than or equal to 1 other than 5.

[0069] The working process of motor unit 3 is described in detail below:

[0070] After passing through the bypass valve 1 and the anti-drop unit 2, the drilling fluid enters the motor unit 3. As the drilling fluid flows down along the fluid passage 321, it exerts an axial pressure on the fluid passage 321. However, since the fluid passage 321 has a spiral structure, it forms an angle with the axis of the motor rotor 32. Due to this angle, the axial pressure of the drilling fluid on the fluid passage 321 can be decomposed into a circumferential component perpendicular to the axis of the motor rotor 32. This circumferential component can drive the motor rotor 32 to rotate circumferentially in the motor stator 31. After passing through the fluid passage 321 and the fluid passage 322, the drilling fluid can flow to the bottom of the motor unit 3.

[0071] Figure 10 A cross-sectional view of the flexible shaft unit in an all-metal cam-type screw impact drill according to exemplary embodiment 1 of the present invention is shown. Figure 11 It shows Figure 1 Enlarged view of section I in the middle.

[0072] like Figure 1 , Figure 2 and Figure 10 As shown, the flexible shaft unit 4 includes a flexible shaft 41, a transmission shaft 42, a flexible shaft housing 43, a transmission key 44, and a bearing 45. The flexible shaft housing 43 is sleeved outside the flexible shaft 41 and the transmission shaft 42. Both the flexible shaft 41 and the transmission shaft 42 have through holes that extend vertically, allowing drilling fluid to flow from the upper end to the lower end of the flexible shaft unit 4 along these through holes.

[0073] In this embodiment, the upper end of the flexible shaft housing 43 is fixedly connected to the lower end of the motor stator 31 by a thread, and the upper end of the flexible shaft 41 is fixedly connected to the lower end of the motor rotor 32 by a thread. Keyways are respectively provided on the lower end of the inner wall of the flexible shaft 41, the upper and lower ends of the outer wall of the transmission shaft 42, and the upper end of the inner wall of the drill bit connector 52. The transmission key 44 is installed in the keyway and is located at the connection between the flexible shaft 41 and the transmission shaft 42, and at the connection between the transmission shaft 42 and the drill bit connector 52, respectively. This achieves circumferential connection of the motor rotor 32, the flexible shaft 41, the transmission shaft 42, and the drill bit connector 52. Fixed, meaning that the flexible shaft 41, drive shaft 42, and drill bit connector 52 can jointly achieve circumferential rotation under the drive of the motor rotor 32. The drill bit connector 52 can then further drive the drill bit connected to its end to achieve circumferential rotation and complete drilling and rock breaking operations. However, the present invention is not limited to this. The flexible shaft housing 43 and the motor stator 31, and the flexible shaft 41 and the motor rotor 32 can also be fixedly connected by other methods besides threaded connections. The flexible shaft 41 and the drive shaft 42, and the drive shaft 42 and the drill bit connector 52 can also be fixedly connected by other methods besides keyed connections. The length of the keyway at the lower end of the drive shaft 42 should be greater than the length of the drive key 44, so that the drill bit connector 52 can generate axial vibration relative to the drive shaft 42 under the action of the cam mechanism 51. The length of the keyway at the upper end of the drive shaft 42 can be greater than the length of the drive key 44, thereby facilitating the installation of the drive key 44 in the keyway.

[0074] Furthermore, the bearing 45 is installed between the flexible shaft housing 43 and the drive shaft 42 to further radially fix the drive shaft 42 within the flexible shaft housing 43, and the bearing 45 does not impede the circumferential rotation of the drive shaft 42. In this embodiment, the number of bearings 45 is one, but the invention is not limited thereto, and the number of bearings 45 may also be two or more.

[0075] The working process of flexible shaft element 4 is described as follows:

[0076] The flexible shaft 41 and the drive shaft 42 rotate circumferentially under the drive of the motor rotor 32, and at the same time transmit the torque to the drill bit joint 52 through the transmission key 44, so that the drill bit joint 52 can also drive the drill bit connected to its end to rotate circumferentially, so as to complete the drilling and rock breaking operation of the drill bit. In addition, the drilling fluid can enter the through hole of the flexible shaft 41 and the drive shaft 42 through the fluid passage hole on the motor rotor 32, and then reach the drill bit through the through hole of the drill bit joint 52, and then be discharged from the drill bit to the bottom of the well.

[0077] like Figure 11As shown, a sealing body 6 and a sealing gasket 7 are provided between the flexible shaft housing 43, the flexible shaft 41, and the motor rotor 32. The sealing body 6 and the sealing gasket 7 are located radially between the inner wall of the flexible shaft housing 43 and the outer wall of the lower end of the motor rotor 32. Axially, the upper and lower ends of the sealing gasket 7 are respectively abutted against the lower end of the sealing body 6 and the upper end of the flexible shaft 41 to achieve axial fixation of the sealing body 6 and the sealing gasket 7. Drilling fluid can flow above the sealing body 6 after passing through the gap between the motor stator 31 and the motor rotor 32, but under the sealing effect of the sealing body 6 and the sealing gasket 7, it cannot enter the gap between the flexible shaft housing 43 and the flexible shaft 41. It can only flow into the flexible shaft 41 through the fluid passage hole on the motor rotor 32.

[0078] Furthermore, sealing rings are provided on the inner and outer walls of the sealing body 6, which can further improve the sealing performance of the sealing body. In this embodiment, there are 3 sealing rings on the outer wall of the sealing body 6 and 2 on the inner wall. The sealing rings are made of metal, which can improve the impact and wear resistance of the sealing rings and thus improve their service life. However, the present invention is not limited to this. The number of sealing rings on the outer wall of the sealing body 6 can also be any positive integer other than 3 and greater than or equal to 1, and the number of sealing rings on the inner wall of the sealing body 6 can also be any positive integer other than 2 and greater than or equal to 1.

[0079] Exemplary Example 2

[0080] This exemplary embodiment provides an application of an all-metal cam-type screw impact drill in rock breaking.

[0081] The application method includes selecting cam mechanisms of different specifications according to different strata and lithological conditions. For example, the size and spacing of the cam rotor and cam stator can be adjusted to give them different impact degrees, achieve different rock-breaking forces within the cycle, avoid continuously superimposing a uniform force, further protect the drill bit, and improve the impact rock-breaking effect within the cycle.

[0082] In summary, the all-metal cam-type screw impact drill described in this invention does not use rubber materials; the entire drill is made of metal, making it adaptable to high temperatures and pressures. It also exhibits better impact and wear resistance, resulting in a longer tool lifespan. To improve the periodic variation of the impact, a cam mechanism consisting of a cam stator and a cam rotor is incorporated, enabling axial movement downhole in a purely mechanical structure. This reduces the complexity of the structure itself, avoids the use of electrical control mechanisms, and eliminates the need for additional energy. The impact amplitude and frequency can be varied by adjusting the spacing between the protrusions in the cam mechanism, improving rock-breaking efficiency and expanding the tool's applicability to some extent. Both the cam stator and cam rotor are detachably connected, as are the internal protrusions, and they are available in various sizes for easy replacement with different sizes. After the contact surfaces between the protrusions wear down, they can be directly re-machined into the next size without requiring complete scrapping, thus improving the recycling rate.

[0083] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A full-metal cam-type screw impact drill, characterized in that, The impact drill bit includes, from top to bottom, a bypass valve, an anti-drop unit, a motor unit, a flexible shaft unit, and an impact unit, wherein: The impact unit includes an impact unit housing, a cam mechanism, and a drill bit connector; the cam mechanism includes a cam stator and a cam rotor arranged sequentially from top to bottom in the cavity of the impact unit housing, the cam stator being fixedly connected to the impact unit housing, and the cam rotor being fixedly connected to the drill bit connector; The upper end face of the cam rotor and the lower end face of the cam stator face each other and always abut against each other; the lower end face of the cam stator and the upper end face of the cam rotor are respectively provided with a number of first protrusions and a number of second protrusions; the cam rotor and the drill bit joint can rotate circumferentially under the drive of the flexible shaft unit. During the circumferential rotation, the first protrusions and the second protrusions will slide periodically relative to each other, so that the cam rotor drives the drill bit joint to generate axial reciprocating motion at the same time. The bypass valve includes a valve body, a valve seat, a valve sleeve, a spring, and a retaining ring. A first side hole is provided on the side wall of the valve body, and a through hole is provided on the valve seat. The lower end of the valve body passes through the through hole. The two ends of the spring are respectively in contact with the valve body and the valve seat. The valve body can move along the axis of the valve seat towards the valve seat and compress the spring under the pressure of the drilling fluid. The valve sleeve is fitted outside the valve body and valve seat. Several second side holes are opened on the side wall of the valve sleeve, and drilling fluid can flow out of the bypass valve through the first side hole and the second side hole. The retaining ring is installed on the inner wall of the valve sleeve, and the lower end of the valve seat abuts against the upper end of the retaining ring. The retaining ring can fix the valve seat in the axial direction. The motor unit includes a motor stator and a motor rotor, with the motor rotor passing through the motor stator and capable of rotating around an axis under the drive of drilling fluid. The outer wall of the motor rotor is provided with several spiral fluid passage grooves, and the lower end is provided with fluid passage holes. Drilling fluid can flow along the fluid passage grooves through the outer wall of the motor rotor and reach the lower end of the motor rotor along the fluid passage holes. The flexible shaft unit includes a flexible shaft, a transmission shaft, and a flexible shaft housing. The lower end of the flexible shaft is fixedly connected to the upper end of the transmission shaft. The flexible shaft housing is sleeved outside the flexible shaft and the transmission shaft. The flexible shaft and the transmission shaft can rotate around the axis under the drive of the motor unit. The impact drill bit also includes a sealing body and a sealing gasket, which are disposed between the motor unit and the flexible shaft unit. The lower end of the sealing body abuts against the upper end of the sealing gasket. The sealing body and the sealing gasket can prevent drilling fluid from passing through the gap between the flexible shaft and the flexible shaft housing.

2. The all-metal cam-type screw impact drill according to claim 1, characterized in that, When there is more than one first protrusion, it is non-uniformly arranged circumferentially on the lower end face of the cam stator, and when there is more than one second protrusion, it is non-uniformly arranged circumferentially on the upper end face of the cam rotor.

3. The all-metal cam-type screw impact drill bit according to claim 1, characterized in that, The anti-drop unit includes an anti-drop plug, an anti-drop short section, and an anti-drop shell. The upper end of the anti-drop short section is fixedly connected to the anti-drop plug. Both the anti-drop plug and the anti-drop short section are inserted into the anti-drop shell. A gap is left between the outer wall of the anti-drop plug and the anti-drop short section and the inner wall of the anti-drop shell to allow drilling fluid to pass through.

4. The all-metal cam-type screw impact drill bit according to claim 1, characterized in that, The flexible shaft unit also includes a bearing, which is sleeved between the flexible shaft housing and the drive shaft, and the bearing can fix the drive shaft in the radial direction.

5. The all-metal cam-type screw impact drill according to claim 1, characterized in that, A drive key is provided between the drive shaft and the drill bit connector, which can circumferentially fix the drive shaft and the drill bit connector.

6. The all-metal cam-type screw impact drill bit according to claim 1, characterized in that, The flexible shaft, drive shaft, and drill bit joint are all provided with a central hole that runs vertically through the center. The upper end of the central hole is connected to the fluid passage hole, allowing drilling fluid to flow along the fluid passage hole and the central hole to the bottom of the drill bit joint.

7. The all-metal cam-type screw impact drill according to claim 1, characterized in that, The impact unit also includes an adapter, which is sleeved on the lower end of the drill bit connector and connected to the outer shell of the impact unit.

8. The application of an all-metal cam-type screw impact drill as described in any one of claims 1 to 7 in rock breaking.

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