Screw drill

Abstract

The invention relates to the field of petroleum drilling tools, in particular to a screw drilling tool, and aims at relieving the technical problem that in the prior art, a spherical hinge shaft limits the output rotating speed of a motor. The screw drill comprises a motor assembly, a transmission shaft assembly and a universal shaft assembly connected between the motor assembly and the transmission shaft assembly. The motor assembly comprises a rotor; the transmission shaft assembly comprises a transmission shaft body; the universal shaft assembly comprises a spherical hinge shaft, the length of the spherical hinge shaft is 1030-1050 mm, one end of the spherical hinge shaft is connected with the end of the rotor through a first arc-shaped roller, and the other end of the spherical hinge shaft is connected to the end of the transmission shaft body through a second arc-shaped roller. By adopting the screw drill, the overall stress of the ball joint shaft is reduced, the internal deformation of the ball joint shaft is reduced, the eccentric torque of the transmission shaft body is also reduced, and the fatigue risk of the transmission shaft body and the ball joint shaft is reduced, so that the service life of the universal shaft assembly and the service life of the transmission shaft assembly can be ensured under the condition that the displacement is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil drilling tools, in particular to a screw drill. BACKGROUND

[0002] In the oil drilling engineering, the turbine drill is generally used for drilling high-hardness strata, but this makes the operation cost high, and the output rotation speed of the existing screw drill is low, which cannot meet the requirement of high-speed cutting.

[0003] In the existing screw drill, one of the main reasons for limiting the output rotation speed of the motor is the universal shaft assembly. The universal shaft assembly includes a spherical hinge shaft connected with the rotor of the motor. When the rotation speed of the rotor is increased by increasing the displacement, the load at both ends of the spherical hinge shaft is increased, the rotation frequency of the spherical hinge shaft is increased, the internal deformation of the spherical hinge shaft is increased, and the service life of the universal shaft assembly is reduced, which directly affects the service life of the entire screw drill. SUMMARY

[0004] The present application aims to provide a screw drill to alleviate the technical problem of limiting the output rotation speed of the motor by the spherical hinge shaft in the prior art.

[0005] To solve the above technical problem, the technical solution provided by the present application is as follows:

[0006] The screw drill provided by the present application comprises a motor assembly, a transmission shaft assembly, and a universal shaft assembly connected between the motor assembly and the transmission shaft assembly.

[0007] The motor assembly comprises a rotor.

[0008] The transmission shaft assembly comprises a transmission shaft body.

[0009] The universal shaft assembly comprises a spherical hinge shaft, the length of the spherical hinge shaft is 1030-1050mm, one end of the spherical hinge shaft is connected with the end of the rotor through a first arc-shaped roller, and the other end of the spherical hinge shaft is connected with the end of the transmission shaft body through a second arc-shaped roller.

[0010] Further, the universal shaft assembly further comprises a rotor joint and a water cap joint.

[0011] The rotor joint is between the rotor and the first arc-shaped roller, and is fixedly connected with the rotor and the first arc-shaped roller, respectively.

[0012] The water cap joint is between the transmission shaft body and the second arc-shaped roller, and is fixedly connected with the transmission shaft body and the second arc-shaped roller, respectively.

[0013] Further, the motor assembly further comprises a stator, the rotor is arranged in the stator, and the ratio of the number of heads of the rotor to the stator is 2:3.

[0014] Further, the inner surface of the stator and the outer surface of the rotor are mutually meshed helical surfaces, and the line type of the helical surface is a short-amplitude hypocycloid.

[0015] Further, the rotor is a solid structure, and both ends of the helical surface of the rotor protrude out of both ends of the helical surface of the stator.

[0016] Further, the stator comprises a rubber bushing, and the inner surface of the rubber bushing is the helical surface.

[0017] Further, the Shore A hardness of the rubber bushing is 85-88.

[0018] Further, the motor assembly further comprises an anti-drop short section, an anti-drop pull rod, and an anti-drop nut.

[0019] The anti-drop short section is fixedly connected to one end of the stator away from the universal shaft assembly.

[0020] One end of the anti-drop pull rod is fixedly connected to one end of the rotor away from the ball hinge shaft, and the other end extends into the anti-drop short section.

[0021] The anti-drop nut is movably arranged in the anti-drop short section and is fixedly connected to the end of the anti-drop pull rod.

[0022] Further, the transmission shaft assembly further comprises a transmission shaft housing, and the universal shaft assembly further comprises a universal shaft housing.

[0023] The transmission shaft housing is sleeved on the transmission shaft body.

[0024] The universal shaft housing is sleeved on the ball hinge shaft, and one end of the universal shaft housing is fixedly connected to the transmission shaft housing, and the other end is fixedly connected to the stator.

[0025] Further, the transmission shaft assembly further comprises an upper radial bearing set, a radial thrust bearing set, and a lower radial bearing set.

[0026] Along the axial direction of the transmission shaft body, the upper radial bearing set, the radial thrust bearing set, and the lower radial bearing set are sequentially fixed in the transmission shaft housing and are all sleeved on the transmission shaft body.

[0027] The technical effects that can be achieved by the screw drill provided by the above technical solutions are as follows:

[0028] The screw drill includes a motor assembly, a transmission shaft assembly, and a universal shaft assembly connected between the motor assembly and the transmission shaft assembly; the motor assembly includes a rotor; the transmission shaft assembly includes a transmission shaft body; and the universal shaft assembly includes a spherical hinge shaft, the length of the spherical hinge shaft is 1030-1050mm, one end of the spherical hinge shaft is connected to the end of the rotor through a first arc-shaped roller, and the other end of the spherical hinge shaft is connected to the end of the transmission shaft body through a second arc-shaped roller.

[0029] In the screw drill, the two ends of the spherical hinge shaft are connected to the rotor and the transmission shaft body through the first arc-shaped roller and the second arc-shaped roller respectively, so that the spherical hinge shaft can rotate in all directions; the length of the spherical hinge shaft is 1030-1050mm, so that the axial eccentric angle of the spherical hinge shaft is reduced, and the axial eccentric angle can be reduced to ≤0.5° according to actual measurement. Through the above design, the stress of the spherical hinge shaft as a whole is reduced, the internal deformation of the spherical hinge shaft is reduced, the eccentric torque of the transmission shaft body is also reduced, and the fatigue risks of the transmission shaft body and the spherical hinge shaft are both reduced. In this way, the service life of the universal shaft assembly and the transmission shaft assembly can be guaranteed in the case of increasing the displacement. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The cross-sectional view of the screw drill provided by the embodiment of the present application;

[0032] Figure 2 The cross-sectional view of the motor assembly provided by the embodiment of the present application;

[0033] Figure 3 The cross-sectional view of the universal shaft assembly provided by the embodiment of the present application;

[0034] Figure 4 The cross-sectional view of the transmission shaft assembly provided by the embodiment of the present application.

[0035] Figure legend: 1-motor assembly; 11-rotor; 12-stator; 13-anti-drop sub; 14-anti-drop pull rod; 15-anti-drop nut; 121-rubber bushing; 122-stator housing;

[0036] 2-transmission shaft assembly; 21-transmission shaft body; 22-transmission shaft housing; 23-upper radial bearing set; 24-thrust bearing set; 25-lower radial bearing set;

[0037] 3 - universal shaft assembly; 31 - spherical hinge shaft; 32 - first arc-shaped roller; 33 - second arc-shaped roller; 34 - rotor joint; 35 - water cap joint; 36 - universal shaft housing. DETAILED DESCRIPTION

[0038] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0040] The following will be combined with the accompanying drawings for the detailed description of some embodiments of the present application. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0041] In the existing screw drill, one of the main reasons for limiting the motor output speed is the universal shaft assembly. The universal shaft assembly includes a spherical hinge shaft connected with the rotor of the motor. When the rotor speed is increased by increasing the displacement, the load at both ends of the spherical hinge shaft is increased, the rotation frequency of the spherical hinge shaft is increased, the internal deformation of the spherical hinge shaft is increased, and the service life of the universal shaft assembly is reduced, which directly affects the service life of the whole screw drill.

[0042] Therefore, the present application provides a screw drill, which comprises a motor assembly 1, a transmission shaft assembly 2 and a universal shaft assembly 3 connected between the motor assembly 1 and the transmission shaft assembly 2; the motor assembly 1 comprises a rotor 11; the transmission shaft assembly 2 comprises a transmission shaft body 21; the universal shaft assembly 3 comprises a spherical hinge shaft 31, the length of the spherical hinge shaft 31 is 1030-1050㎜, one end of the spherical hinge shaft 31 is connected with the end of the rotor 11 through a first arc-shaped roller 32, and the other end of the spherical hinge shaft 31 is connected with the end of the transmission shaft body 21 through a second arc-shaped roller 33.

[0043] In the screw drill, the two ends of the ball joint shaft 31 are connected to the rotor 11 and the transmission shaft body 21 through the first arc-shaped roller 32 and the second arc-shaped roller 33 respectively, so that the ball joint shaft 31 can be rotated in all directions; the length of the ball joint shaft 31 is 1030-1050mm, i.e. 1030mm, 1040mm or 1050mm, etc., so that the axial eccentric angle is reduced, and according to the actual measurement, it can be as low as ≤0.5°. By such design, the stress of the ball joint shaft 31 as a whole is reduced, the internal deformation is reduced, the eccentric torque of the transmission shaft body 21 is also reduced, and the fatigue risks of the transmission shaft body 21 and the ball joint shaft 31 are both reduced. In this way, in the case of increasing the displacement, the service life of the universal shaft assembly 3 and the transmission shaft assembly 2 can be guaranteed.

[0044] The following will be described in detail in combination with Figures 1 to 4 The structure and shape of the screw drill provided in the embodiment will be described in detail:

[0045] Referring to Figures 1 to 4 , from top to bottom, the motor assembly 1, the universal shaft assembly 3 and the transmission shaft assembly 2 are sequentially distributed. Regarding the motor assembly 1, specifically:

[0046] Referring to Figure 1 and Figure 2 , the motor assembly 1 further includes a stator 12, which optionally includes a rubber bushing 121 and a stator housing 122, the rubber bushing 121 being fixed to the inner wall of the stator housing 122; the rotor 11 is arranged in the stator 12, the outer surface of the rotor 11 and the inner surface of the rubber bushing 121 are helical surfaces that are engaged with each other, and the two ends of the helical surface of the rotor 11 protrude out of the two ends of the helical surface of the rubber bushing 121. In addition, the stator 12 can be an integrally formed steel pipe with an internal helical surface.

[0047] Referring to Figure 2 , more preferably, the head ratio of the rotor 11 to the stator 12 is 2:3. Compared with the conventional head ratio of 7:8, the rotational speed of the rotor 11 is more than 2.5 times under the same displacement.

[0048] More preferably, the line type of the helical surface adopts a short-amplitude internal cycloid, so that the rotor 11 eccentricity is increased, the stator 12 lead is shortened, and the flow area is reduced. According to the rotor 11 rotational speed formula n=60Q / A G NT S (wherein, n represents the rotational speed of the rotor 11, Q represents the displacement, A G represents the flow area, N represents the number of heads of the rotor 11, and T S represents the lead of the stator 12), the rotational speed of the rotor 11 can be greatly improved. For details, please refer to the following embodiments:

[0049] In practical application, the measured flow area is reduced from 3112.3 square millimeters to 2221.5 square millimeters, the eccentricity is increased from 6.5mm to 10.4mm, the stator 12 lead is shortened from 914mm to 660mm, according to the formula, the rotor 11 speed can be changed to nearly seven times the original, when the displacement of the liquid is 28 liters per second, the rotor 11 speed can reach n≥400r / min, the efficiency of the whole machine is ≥50%.

[0050] More preferably, the Shore A hardness of the rubber bushing 121 is 85-88, i.e. 85, 87 or 88, etc. With such a design, the ability of the rubber bushing 121 to resist extrusion stress is improved, thereby delaying the degree of wear, allowing the motor assembly 1 to maintain a relatively reliable seal, i.e. to improve the efficiency of the motor assembly 1 and stabilize the output performance, while also improving the service life.

[0051] More preferably, the rotor 11 is a steel solid structure, which has high overall strength and can meet the requirements of high-speed operation.

[0052] Continuing to refer to Figure 1 and Figure 2 , the motor assembly 1 further comprises a drop prevention assembly, which comprises a drop prevention sub 13, a drop prevention pull rod 14 and a drop prevention nut 15; the drop prevention sub 13 is threadedly connected to one end of the stator 12 away from the universal shaft assembly 3; one end of the drop prevention pull rod 14 is threadedly connected to one end of the rotor 11 away from the spherical hinge shaft 31, and the other end extends into the drop prevention sub 13; the drop prevention nut 15 is movably arranged in the drop prevention sub 13 and is threadedly connected to the end of the drop prevention pull rod 14.

[0053] With the above design, when the screw drill housing is broken or tripped due to abnormal reasons, it can prevent falling into the well, and at the same time, the pump pressure is increased to allow the operator to discover the problem in time and avoid accidents. It should be noted that the functional principle of the drop prevention assembly belongs to the prior art, which will not be described in detail here.

[0054] Regarding the universal shaft assembly 3 and the transmission shaft assembly 2, specifically:

[0055] Referring to Figures 1 to 4 , the universal shaft assembly 3 further comprises a rotor joint 34, a water cap joint 35 and a universal shaft housing 36; the transmission shaft assembly 2 further comprises a transmission shaft housing 22, an upper radial bearing set 23, a radial thrust bearing set 24 and a lower radial bearing set 25.

[0056] In the above, with Figure 1For example, the upper end of the universal shaft housing 36 is screwed to the stator housing 122, and the lower end is screwed to the transmission shaft housing 22; the rotor joint 34 is screwed to the lower end of the rotor 11, and the first arc-shaped roller 32 is fixed thereon; the water cap joint 35 is screwed to the upper end of the transmission shaft body 21, and the second arc-shaped roller 33 is fixed thereon. From top to bottom, the upper radial bearing set 23, the radial-thrust bearing set 24, and the lower radial bearing set 25 are sequentially fixed in the transmission shaft housing 22, and are all sleeved on the transmission shaft body 21.

[0057] Reference Figures 1 to 4 In the screw drill provided by the embodiment of the present application, the rotor 11 and the stator 12 have a head number ratio of 2:3, which makes the output rotation speed of the rotor 11 be more than 2.5 times of that of the conventional screw drill with the same displacement; the rubber bushing 121 is made of hard rubber, which increases the resistance of the rubber bushing 121 to the extrusion stress of the rotor 11 under the action of the centrifugal inertia force, delays the wear degree, reduces the extrusion stress and wear of the rubber bushing 121, and thus makes the motor assembly 1 be able to keep a relatively reliable sealing, that is, the efficiency and output performance of the motor assembly 1 are improved and stabilized, and the service life is improved; when the disc rotates, the outer housing of the screw drill rotates, and since the length of the ball joint shaft 31 is set to 1030-1050㎜, the axial eccentric angle of the ball joint shaft 31 is reduced, and the eccentric torque received by the transmission shaft body 21 is also reduced, thereby greatly reducing the fatigue risk of the ball joint shaft 31 and the transmission shaft body 21, prolonging the service life of the universal shaft assembly 3 and the transmission shaft assembly 2, and further prolonging the service life of the screw drill.

[0058] Therefore, the screw drill provided by the present application can be stably used in a high-hard formation, thereby replacing the turbine drill, and the means for prolonging the service life of the ball joint shaft 31 is simple, low in production cost, high in reliability, and convenient to maintain, can significantly reduce the failure rate of drilling operation, and improve the safety and work efficiency on site.

[0059] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A screw drill, characterized by It comprises: a motor assembly (1), a transmission shaft assembly (2) and a universal shaft assembly (3) connected between the motor assembly (1) and the transmission shaft assembly (2); the motor assembly (1) comprises a rotor (11); the transmission shaft assembly (2) comprises a transmission shaft body (21); the universal shaft assembly (3) comprises a spherical hinge shaft (31), the length of the spherical hinge shaft (31) is 1030-1050mm, one end of the spherical hinge shaft (31) is connected with the end of the rotor (11) through a first arc-shaped roller (32), and the other end of the spherical hinge shaft (31) is connected with the end of the transmission shaft body (21) through a second arc-shaped roller (33).

2. The screw-in drill according to claim 1, characterized in that The universal shaft assembly (3) further comprises a rotor joint (34) and a water cap joint (35); the rotor joint (34) is between the rotor (11) and the first arc-shaped roller (32) and is fixedly connected with the rotor (11) and the first arc-shaped roller (32) respectively; the water cap joint (35) is between the transmission shaft body (21) and the second arc-shaped roller (33) and is fixedly connected with the transmission shaft body (21) and the second arc-shaped roller (33) respectively.

3. The screw-in drill according to claim 1, characterized in that The motor assembly (1) further comprises a stator (12), the rotor (11) is arranged in the stator (12), and the head ratio of the rotor (11) to the stator (12) is 2:

3.

4. The screw-in drill according to claim 3, characterized in that The inner surface of the stator (12) and the outer surface of the rotor (11) are helical surfaces that mesh with each other, and the line type of the helical surface is short-amplitude epitrochoid.

5. The screw-in drill according to claim 4, characterized in that The rotor (11) is of solid structure, and both ends of the helical surface of the rotor (11) protrude beyond both ends of the helical surface of the stator (12).

6. The screw-in drill according to claim 5, characterized in that The stator (12) comprises a rubber bushing (121), and the inner surface of the rubber bushing (121) is the helical surface.

7. The screw-in drill according to claim 6, characterized in that The Shore A hardness of the rubber bushing (121) is 85-88.

8. The screw-in drill according to claim 3, characterized in that The motor assembly (1) further comprises an anti-drop short section (13), an anti-drop pull rod (14) and an anti-drop nut (15); the anti-drop short section (13) is fixedly connected with the end of the stator (12) away from the universal shaft assembly (3); one end of the anti-drop pull rod (14) is fixedly connected with the end of the rotor (11) away from the spherical hinge shaft (31), and the other end of the anti-drop pull rod (14) extends into the anti-drop short section (13); the anti-drop nut (15) is movably arranged in the anti-drop short section (13) and is fixedly connected with the end of the anti-drop pull rod (14).

9. The screw-in drill according to claim 3, characterized in that The transmission shaft assembly (2) further comprises a transmission shaft housing (22), and the universal shaft assembly (3) further comprises a universal shaft housing (36); the transmission shaft housing (22) is sleeved on the transmission shaft body (21); the universal shaft housing (36) is sleeved on the spherical hinge shaft (31), and one end of the universal shaft housing (36) is fixedly connected with the transmission shaft housing (22), and the other end of the universal shaft housing (36) is fixedly connected with the stator (12).

10. The screw-in drill according to claim 9, characterized in that The transmission shaft assembly (2) further comprises an upper radial bearing set (23), a radial thrust bearing set (24) and a lower radial bearing set (25); Along the axial direction of the transmission shaft body (21), the upper radial bearing set (23), the radial-thrust bearing set (24) and the lower radial bearing set (25) are sequentially fixed in the transmission shaft housing (22) and are all sleeved on the transmission shaft body (21).

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