An axial motion amplifier for a screw drill

Abstract

The application relates to an axial motion amplifier for a screw drill, comprising an outer shell which is a hollow pipe structure with both ends communicated, a first curve periodically fluctuating along the axial direction of the outer shell is arranged on the inner wall of the outer shell; a lower shaft is arranged in the outer shell and is spaced from the outer shell, a second curve periodically fluctuating along the axial direction of the lower shaft is arranged on the outer wall of the lower shaft; a coupling rod is arranged between the first curve of the outer shell and the second curve of the lower shaft, the period of the first curve is greater than that of the second curve; the lower shaft drives the axial reciprocating motion of the outer shell through the coupling rod, and the axial displacement of the outer shell is amplified, so that the axial displacement of the outer shell is greater than the axial displacement of the lower shaft. When the rotary punching assembly drives the axial reciprocating motion of the lower shaft, the second curve of the lower shaft doubles the driving of the coupling rod to drive the axial reciprocating motion of the outer shell, and then the axial motion amplifier doubles the small axial displacement generated by the rotary punching assembly, so that the efficiency of drilling is improved.

Description

Technical Field

[0001] This application relates to the field of rotary screw drill tools for oil and gas drilling, and particularly to an axial motion amplifier for screw drill tools. Background Technology

[0002] In oil and gas extraction, rotary screw drills are increasingly widely used. A rotary screw drill mainly consists of a motor assembly, a universal joint housing, a universal joint assembly, and a rotary impact assembly. The universal joint assembly converts the planetary motion of the motor rotor into the fixed-axis motion of the upper and lower main shafts of the rotary impact assembly. This allows the torque and speed generated by the motor to be transmitted to the drive shaft, where the rotary impact assembly generates axial impact, driving the drill bit to increase its rock-breaking energy. Therefore, the rotary impact assembly of the rotary screw drill is a crucial component; its output axial impact force determines the drill bit's rock-breaking efficiency.

[0003] Currently, the magnitude of the axial impact force of the rotary punch assembly in a rotary punch screw drill is determined by the maximum and minimum heights of its cam. Although there is a certain height difference in the cam design, due to the high rotational speed of the rollers in the rotary punch assembly, the impact does not occur from the highest point to the lowest point of the cam. Instead, the impact occurs from the highest point in the middle to a point in the middle of the cam curve, the exact point of which is determined by the motor speed.

[0004] Therefore, it is evident that the impact force generated by the rotary impact assembly is not fully utilized, resulting in a less significant drilling speed-up effect. However, directly increasing the height difference between the highest and lowest points of the cam increases the slope of the cam curve, creating difficulties for the rollers to climb on the cam surface, thus reducing the torque generated by the motor. Furthermore, this method of increasing the roller impact on the cam can significantly increase the impact stroke. Summary of the Invention

[0005] This application provides an axial motion amplifier for screw drills to solve the problem that the impact force generated by the rotary punch assembly in related technologies has a poor effect on drilling speed.

[0006] This application provides an axial motion amplifier for a screw drill, comprising:

[0007] The outer shell is a hollow tube structure with both ends connected, and the inner wall of the outer shell is provided with a first curve that periodically fluctuates along the axial direction of the outer shell.

[0008] The lower shaft is located inside the outer casing and spaced apart from the outer casing. The outer wall of the lower shaft is provided with a periodically fluctuating second curve along the axial direction of the lower shaft.

[0009] A coupling rod is located between a first curve of the outer shell and a second curve of the lower shaft, wherein the period of the first curve is greater than the period of the second curve;

[0010] The lower shaft drives the outer shell to reciprocate axially via the coupling rod, and amplifies the axial displacement of the outer shell so that the axial displacement of the outer shell is greater than the axial displacement of the lower shaft.

[0011] In some embodiments, a retainer is also included. The retainer is a hollow tube structure and is sleeved on the outer periphery of the lower shaft. The retainer has radially opened positioning through holes for axially and circumferentially positioning the coupling rod.

[0012] In some embodiments: a plurality of positioning through holes are provided on the retainer, and the plurality of positioning through holes are arranged sequentially at intervals along the axial and circumferential directions of the retainer;

[0013] The coupling rod is provided in multiple ways, and each of the multiple coupling rods is located in a corresponding position through hole.

[0014] In some embodiments: the coupling rod includes a cylinder located in the positioning through hole and perpendicular to the axis of the lower shaft, one end of the cylinder is provided with a first ball head that contacts the curved surface of the first curve, and the other end of the cylinder is provided with a second ball head that contacts the curved surface of the second curve.

[0015] In some embodiments: the radius of curvature of the first ball head is smaller than the radius of curvature of the first curve, and the radius of curvature of the second ball head is smaller than the radius of curvature of the second curve.

[0016] In some embodiments: the lower end of the outer casing is provided with a shoulder with a reduced aperture, the top of the shoulder is provided with a mounting hole for mounting an elastic buffer, the diameter of the mounting hole is larger than the diameter of the lower shaft, and the bottom surface of the lower shaft is in contact with the elastic buffer.

[0017] In some embodiments: the top of the outer casing and the top of the lower shaft are connected by a key, and keyways are provided on the inner wall of the outer casing and the outer wall of the lower shaft. The key is located in the keyway so that the outer casing and the lower shaft can rotate synchronously in the circumferential direction.

[0018] In some embodiments: the top of the outer casing limits the lower shaft to a locking nut inside the outer casing, the locking nut being located on top of the key and threadedly connected to the inner wall of the outer casing, and an axial clearance is pre-set between the locking nut and the key.

[0019] In some embodiments: a mud flow channel is provided inside the lower shaft along the axial direction of the lower shaft, and a threaded hole for connecting the drill bit is provided at the bottom of the outer casing, and the threaded hole is in communication with the mud flow channel.

[0020] In some embodiments: the first curve and the second curve are both sine curves or cosine curves, the wavelength of the second curve is greater than the wavelength of the first curve, and the minimum gap between the peaks of the first curve and the second curve is less than the length of the coupling rod.

[0021] The beneficial effects of the technical solution provided in this application include:

[0022] This application provides an axial motion amplifier for a screw drill. The axial motion amplifier includes an outer shell, which is a hollow tube structure with both ends connected. A first curve, periodically oscillating along the axial direction of the outer shell, is provided on the inner wall of the outer shell. A lower shaft is located inside the outer shell and spaced apart from it. A second curve, periodically oscillating along the axial direction of the lower shaft, is provided on the outer wall of the lower shaft. A coupling rod is located between the first curve of the outer shell and the second curve of the lower shaft. The period of the first curve is greater than the period of the second curve. The lower shaft drives the outer shell to reciprocate axially through the coupling rod, amplifying the axial displacement of the outer shell so that the axial displacement of the outer shell is greater than the axial displacement of the lower shaft.

[0023] Therefore, the axial motion amplifier for screw drills of this application has a first periodic oscillation curve and a second periodic oscillation curve respectively set on the inner wall of the housing and the outer wall of the lower shaft. The period of the first curve is greater than the period of the second curve, so that the slope of the first curve is less than the slope of the second curve. When the rotary punch assembly drives the lower shaft to reciprocate axially, the second curve of the lower shaft doubles the driving force of the coupling rod to drive the housing to reciprocate axially. The coupling rod drives the first curve on the inner surface of the housing, thereby accelerating the axial motion amplifier to double the amplification of the small axial displacement generated by the rotary punch assembly, increasing the impact force generated by the rotary punch assembly, increasing the rock-breaking energy, and improving drilling efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the outer casing of an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the lower shaft structure according to an embodiment of this application;

[0028] Figure 4 This is a schematic diagram of the coupling rod in an embodiment of this application;

[0029] Figure 5 for Figure 1 A cross-sectional view along the AA direction.

[0030] Figure label:

[0031] 1. Lower shaft; 2. Locking nut; 3. Key; 4. Cage; 5. Coupling rod; 6. Elastic buffer; 7. Outer shell; 1a. Second curve; 2a. Axial clearance; 7a. First curve. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] This application provides an axial motion amplifier for screw drills, which can solve the problem that the impact force generated by the rotary punch assembly has a poor effect on drilling speed in related technologies.

[0034] See Figures 1 to 4 As shown, this application embodiment provides an axial motion amplifier for a screw drill bit, comprising:

[0035] The outer shell 7 is a hollow tube structure with both ends connected. A first curve 7a is provided on the inner wall of the outer shell 7, which is periodically fluctuating along the axial direction of the outer shell 7. The first curve 7a is preferably, but not limited to, a sine curve.

[0036] The lower shaft 1 is coaxially located inside the outer shell 7 and spaced apart from the outer shell 7. A periodically fluctuating second curve 1a is provided on the outer wall of the lower shaft 1 along the axial direction of the lower shaft 1. The second curve 1a is preferably, but not limited to, a sine curve.

[0037] The coupling rod 5 is located between the first curve 7a of the outer shell 7 and the second curve 1a of the lower shaft 1. The period of the first curve 7a is greater than the period of the second curve 1a, so that the radius of curvature of the first curve 7a is greater than the radius of curvature of the second curve 1a, and thus the slope of the second curve 1a is greater than the slope of the first curve 7a.

[0038] When the lower shaft 1 drives the outer shell 7 to reciprocate axially through the coupling rod 5, since the slope of the second curve 1a is greater than the slope of the first curve 7a, the first curve 1a of the lower shaft 1 will drive the coupling rod 5 to reciprocate axially more than the first curve 7a, thereby amplifying the ratio of the axial displacement of the outer shell 7 to the axial displacement of the lower shaft 1.

[0039] The axial motion amplifier for a screw drill tool in this embodiment has a first periodic oscillation curve 7a and a second periodic oscillation curve 1a respectively provided on the inner wall of the housing 7 and the outer wall of the lower shaft 1. The period of the first curve 7a is greater than the period of the second curve 1a, so that the slope of the first curve 7a is less than the slope of the second curve 1a.

[0040] When the rotary punch assembly drives the lower shaft 1 to reciprocate axially, the second curve 1a of the lower shaft 1 doubles the driving force of the coupling rod 5 to drive the outer shell 7 to reciprocate axially. The coupling rod 5 drives the first curve 7a on the inner surface of the outer shell 7, thereby accelerating the axial motion amplifier to double the amplification of the small axial displacement generated by the rotary punch assembly, increasing the impact force generated by the rotary punch assembly, increasing the rock-breaking energy, and improving drilling efficiency.

[0041] In some alternative embodiments: see Figure 1 As shown, this application embodiment provides an axial motion amplifier for a screw drill bit. The axial motion amplifier also includes a retainer 4, which is a hollow tube structure and is sleeved on the outer periphery of the lower shaft 1. The retainer 4 has a positioning through hole for axial and circumferential positioning coupling rods 5 radially opened.

[0042] Multiple positioning through holes are provided on the retainer 4, and these holes are arranged sequentially and at intervals along the axial and circumferential directions of the retainer 4. Multiple coupling rods 5 are provided, each corresponding to one of the multiple positioning through holes. The multiple coupling rods 5 can work synchronously or independently.

[0043] In this embodiment, a retainer 4 for positioning coupling rods 5 is provided between the lower shaft 1 and the outer casing 7. The retainer 4 has radially opened positioning through holes for axial and circumferential positioning coupling rods 5. The coupling rods 5 can be arranged axially and circumferentially on the retainer 4 to increase the axial force between the lower shaft 1 and the outer casing 7, thereby improving the service life and working efficiency of the axial motion amplifier.

[0044] In some alternative embodiments: see Figure 4 As shown, this application embodiment provides an axial motion amplifier for a screw drill. The coupling rod 5 of the axial motion amplifier includes a cylinder located in a positioning through hole and perpendicular to the axis of the lower shaft. One end of the cylinder is provided with a first ball head that contacts the curved surface of the first curve 7a, and the other end of the cylinder is provided with a second ball head that contacts the curved surface of the second curve 1a.

[0045] The radius of curvature of the first ball head is smaller than that of the first curve 7a, and the radius of curvature of the second ball head is smaller than that of the second curve 1a, so that the first ball head and the second ball head of the coupling rod 5 can reliably contact the valley bottom of the first curve 7a and the valley bottom of the second curve 1a, respectively.

[0046] In some alternative embodiments: see Figure 1 and Figure 2 As shown, this application embodiment provides an axial motion amplifier for a screw drill. The lower end of the outer housing 7 of the axial motion amplifier is provided with a shoulder with a reduced aperture. A mounting hole for mounting an elastic buffer 6 is provided on the top of the shoulder. The diameter of the mounting hole is larger than the diameter of the lower shaft 1. The bottom surface of the lower shaft 1 is in contact with the elastic buffer 6.

[0047] In this embodiment, an elastic buffer 6 for buffering the lower shaft 1 is provided at the lower end of the outer shell 7. The elastic buffer 6 is preferably, but not limited to, multiple overlapping butterfly springs. The number of butterfly springs can be adjusted according to the magnitude of the buffering force. The elastic buffer 6 is in contact with the bottom surface of the lower shaft 1 to buffer the impact axial force of the lower shaft 1 on the outer shell 7 and avoid damage to the screw drill due to excessive impact axial force.

[0048] In some alternative embodiments: see Figure 1 and Figure 5 As shown, this application embodiment provides an axial motion amplifier for a screw drill. The top of the outer housing 7 of the axial motion amplifier is connected to the top of the lower shaft 1 by a key 3. Both the inner wall of the outer housing 7 and the outer wall of the lower shaft 1 are provided with keyways. The key 3 is located in the keyway so that the outer housing 7 and the lower shaft 1 can rotate synchronously in the circumferential direction.

[0049] In this embodiment, the top of the outer shell 7 and the top of the lower shaft 1 are connected by a key 3 so that the outer shell 7 and the lower shaft 1 rotate synchronously in the circumferential direction, so that the torque of the lower shaft 1 is transmitted to the outer shell 7, so that the drill bit at the bottom of the outer shell 7 cuts the formation.

[0050] In some alternative embodiments: see Figure 1 As shown, this application embodiment provides an axial motion amplifier for a screw drill. The top of the outer housing 7 of the axial motion amplifier limits the lower shaft 1 to a locking nut 2 inside the outer housing 7. The locking nut 2 is located on top of the key 3 and is threadedly connected to the inner wall of the outer housing 7. The lower shaft 1 is located inside the locking nut 2 and extends out of the outer housing 7. An axial clearance 2a is preset between the locking nut 2 and the key 3 to allow the outer housing 7 to move axially relative to the lower shaft 1.

[0051] A mud flow channel is provided inside the lower shaft 1 along the axial direction of the lower shaft 1. A threaded hole for connecting the drill bit is provided at the bottom of the outer shell 7. The threaded hole and the mud flow channel are interconnected. Drilling fluid flows through the mud flow channel and the threaded hole in sequence into the drill bit to circulate the rock cuttings in the wellbore and cool the drill bit.

[0052] In some alternative embodiments: see Figure 1 As shown, this application embodiment provides an axial motion amplifier for a screw drill. The first curve 7a and the second curve 1a of this axial motion amplifier are both sine or cosine curves. The wavelength of the second curve 1a is greater than the wavelength of the first curve 7a. The gap between the peaks of the first curve 7a and the second curve 1a is less than the length of the coupling rod 5, so that the coupling rod 5 transmits the axial force of the lower shaft 1 to the outer casing 7. The first curve 7a is preferably a helical structure rotating about the axis of the outer casing 7, and the second curve 1a is preferably a helical structure rotating about the axis of the lower shaft 1, facilitating the insertion of the retainer 4 and the coupling rod 5 into the outer casing 7.

[0053] Working principle

[0054] This application provides an axial motion amplifier for a screw drill. The axial motion amplifier includes a housing 7, which is a hollow tube structure with both ends connected. A first curve 7a, periodically oscillating along the axial direction of the housing 7, is provided on the inner wall of the housing 7. A lower shaft 1 is located inside the housing 7 and spaced apart from it. A second curve 1a, periodically oscillating along the axial direction of the lower shaft 1, is provided on the outer wall of the lower shaft 1. A coupling rod 5 is located between the first curve 7a of the housing 7 and the second curve 1a of the lower shaft 1. The period of the first curve 7a is greater than the period of the second curve 1a. The lower shaft 1 drives the housing 7 to reciprocate axially through the coupling rod 5, amplifying the axial displacement of the housing 7 by a factor of the axial displacement of the lower shaft 1.

[0055] Therefore, the axial motion amplifier for screw drills of this application has a periodically fluctuating first curve 7a and a periodically fluctuating second curve 1a respectively set on the inner wall of the housing 7 and the outer wall of the lower shaft 1. The period of the first curve 7a is greater than the period of the second curve 1a, so that the slope of the first curve 7a is less than the slope of the second curve 1a. When the rotary punch assembly drives the lower shaft 1 to reciprocate axially, the second curve 1a of the lower shaft 1 doubles the driving force of the coupling rod 5 to drive the housing 7 to reciprocate axially. The coupling rod 5 drives the first curve 7a on the inner surface of the housing 7, thereby accelerating the axial motion amplifier to double the amplification of the small axial displacement generated by the rotary punch assembly, increasing the impact force generated by the rotary punch assembly, increasing the rock-breaking energy, and improving drilling efficiency.

[0056] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0057] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An axial motion amplifier for screw drills, characterized in that, include: The outer shell (7) is a hollow tube structure with both ends connected. The inner wall of the outer shell (7) is provided with a first curve (7a) that periodically fluctuates along the axial direction of the outer shell (7). The lower shaft (1) is located inside the outer shell (7) and spaced apart from the outer shell (7). The outer wall of the lower shaft (1) is provided with a periodically fluctuating second curve (1a) along the axial direction of the lower shaft (1). The coupling rod (5) is located between the first curve (7a) of the outer shell (7) and the second curve (1a) of the lower shaft (1), wherein the period of the first curve (7a) is greater than the period of the second curve (1a); The lower shaft (1) drives the outer shell (7) to reciprocate axially through the coupling rod (5) and amplifies the axial displacement of the outer shell (7) so that the axial displacement of the outer shell (7) is greater than the axial displacement of the lower shaft (1).

2. The axial motion amplifier for a screw drill as described in claim 1, characterized in that: It also includes a retainer (4), which is a hollow tube structure and is sleeved on the outer periphery of the lower shaft (1). The retainer (4) has radially opened positioning through holes for axially and circumferentially positioning the coupling rod (5).

3. The axial motion amplifier for a screw drill as described in claim 2, characterized in that: Multiple positioning through holes are provided on the retainer (4), and the multiple positioning through holes are arranged sequentially and at intervals along the axial and circumferential directions of the retainer (4); The coupling rod (5) is provided in multiple ways, and the multiple coupling rods (5) are respectively located in the multiple positioning through holes.

4. An axial motion amplifier for a screw drill as described in claim 2, characterized in that: The coupling rod (5) includes a cylinder located in the positioning through hole and perpendicular to the axis of the lower shaft. One end of the cylinder is provided with a first ball head that contacts the curved surface of the first curve (7a), and the other end of the cylinder is provided with a second ball head that contacts the curved surface of the second curve (1a).

5. An axial motion amplifier for a screw drill as described in claim 4, characterized in that: The radius of curvature of the first ball head is smaller than the radius of curvature of the first curve (7a), and the radius of curvature of the second ball head is smaller than the radius of curvature of the second curve (1a).

6. An axial motion amplifier for a screw drill as described in claim 1, characterized in that: The lower end of the outer shell (7) is provided with a shoulder with a reduced aperture. The top of the shoulder is provided with a mounting hole for installing an elastic buffer (6). The diameter of the mounting hole is larger than the diameter of the lower shaft (1). The bottom surface of the lower shaft (1) is in contact with the elastic buffer (6).

7. An axial motion amplifier for a screw drill as described in claim 1, characterized in that: The top of the outer shell (7) is connected to the top of the lower shaft (1) by a key (3). The inner wall of the outer shell (7) and the outer wall of the lower shaft (1) are both provided with keyways. The key (3) is located in the keyway so that the outer shell (7) and the lower shaft (1) can rotate synchronously in the circumferential direction.

8. An axial motion amplifier for a screw drill as described in claim 7, characterized in that: The top of the outer casing (7) is provided with a locking nut (2) that limits the lower shaft (1) inside the outer casing (7). The locking nut (2) is located on the top of the key (3) and is threaded to the inner wall of the outer casing (7). An axial gap (2a) is preset between the locking nut (2) and the key (3).

9. An axial motion amplifier for a screw drill as described in claim 1, characterized in that: A mud flow channel is provided inside the lower shaft (1) along the axial direction of the lower shaft (1), and a threaded hole for connecting the drill bit is provided at the bottom of the outer shell (7), and the threaded hole is connected to the mud flow channel.

10. An axial motion amplifier for a screw drill as described in claim 1 or 2, characterized in that: The first curve (7a) and the second curve (1a) are both sine curves or cosine curves. The wavelength of the second curve (1a) is greater than the wavelength of the first curve (7a). The gap between the peak of the first curve (7a) and the peak of the second curve (1a) is less than the length of the coupling rod (5).

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