A screw drill

Abstract

This invention provides a screw drill bit, including a rotor, a stator housing, and a rubber bushing. The rubber bushing is disposed within the stator housing and has a first mounting hole along its axial direction. The rotor is disposed within the mounting hole and forms a conjugate sealing cavity with the mounting hole. The conjugate sealing cavity is connected to drilling fluid. The rotor has a first through hole along its axial direction and multiple second through holes spaced apart along its radial direction. The second through holes connect the first through holes to the conjugate sealing cavity, and the first through holes are connected to lubricant. By providing the first through holes on the rotor, which are connected to the lubricant, the drilling fluid enters the conjugate sealing cavity and drives the rotor to rotate. During the rotor's rotation, the lubricant enters the conjugate sealing cavity from the first through holes through the second through holes, achieving lubrication and drag reduction for the rotor and the rubber bushing. The screw drill bit of this embodiment has a simple structure and improves the service life of the rotor and the rubber bushing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of power drilling tools, and particularly relates to a screw rod drilling tool. BACKGROUND

[0002] The screw rod drilling tool motor assembly is the core of the screw rod drilling tool and the power source of the screw rod drilling tool, and is usually composed of a rotor and a stator. The rotor is a steel screw rod with a wear-resistant material plated on the surface thereof. The stator includes a steel outer cylinder and a rubber bushing injected into the inner wall of the outer cylinder. The rotor and the stator rubber bushing are engaged with each other. The lead difference between the rotor and the stator rubber bushing forms a plurality of continuous but different space conjugate sealing cavities between the curved surfaces of the rotor and the stator rubber bushing to accommodate the drilling fluid. When the drilling fluid passes through the plurality of continuous sealing cavities, the rotor is driven to rotate. The sealing cavities move along the axial direction and are continuously generated and disappeared to complete energy conversion. The torque and the rotating speed are transmitted to the drill bit through the universal shaft and the transmission shaft.

[0003] However, during the use of the screw rod drilling tool, the motor assembly mainly has the following problems: ① rotor abrasion. During the operation of the motor, the rotor and the stator are exposed to the drilling fluid and are abraded by the solid particles in the drilling fluid. At the same time, the rotor and the stator rubber bushing are in interference fit, and the rotor rotates at a high speed relative to the stator. The continuous frictional resistance between the rotor and the stator will further deteriorate the abrasion of the surface of the rotor, and even form an abrasion hole on the surface of the rotor. ② Rubber bushing thermal failure. With the rotation of the rotor, the stator rubber bushing bears the high-frequency cyclic alternating load of the rotor. The alternating load and the continuous friction will cause heat accumulation and form hysteresis heat. With the increase of the temperature, the physical properties of the stator rubber bushing decrease, the aging is accelerated, and phenomena such as chunking and falling off occur. At the same time, the rubber bushing is deformed by volume expansion, which increases the interference amount between the stator and the rotor, further aggravates the abrasion of the contact surface between the stator and the rotor and the generation of friction heat, and accelerates the damage of the stator and the rotor. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a high-life bionic light-weight screw rod drilling tool motor assembly to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0006] A screw rod drilling tool includes a rotor, a stator shell and a rubber bushing. The rubber bushing is arranged in the stator shell. The rubber bushing is provided with a first mounting hole in the axial direction. The rotor is arranged in the mounting hole and forms a conjugate sealing cavity with the mounting hole. The conjugate sealing cavity is connected with the drilling fluid. The rotor is provided with a first through hole in the axial direction. A plurality of second through holes are arranged in the axial direction in the radial direction. The second through holes are used to connect the first through hole and the conjugate sealing cavity. The first through hole is connected with a lubricant.

[0007] Preferably, each of the second through holes is provided with a steel ball, which is matched with the second through hole and can roll within the second through hole.

[0008] Preferably, the stator housing is further provided with a second mounting hole, which communicates with the first mounting hole. An elastic bladder is provided in the second mounting hole, and lubricant is provided in the elastic bladder. The elastic bladder communicates with the first through hole. The second mounting hole is also provided with a flow pipe, which communicates with the conjugate sealing cavity. Drilling fluid enters the conjugate sealing cavity through the flow pipe.

[0009] Preferably, the rubber bushing has multiple main leaf vein through holes arranged circumferentially along its axial direction, and multiple branch leaf vein through grooves arranged axially at intervals along its radial direction. The branch leaf vein through grooves communicate with the main leaf vein through holes, and supercoolant is pre-placed in the branch leaf vein through grooves and the main leaf vein through holes.

[0010] Preferably, the screw drill further includes: foam steel, disposed in the first through hole, the foam steel body having holes that communicate with the first through hole.

[0011] Preferably, the rotor is a screw, and the rubber bushing is threaded to match the rotor, with each main blade vein through hole following the thread of the rubber bushing.

[0012] Preferably, the outer circumference shape of the rotor is characterized by alternating spiral ridges and spiral grooves, with a second through hole located on the spiral ridge.

[0013] Preferably, the subcoolant is an ethylene glycol-based coolant.

[0014] Preferably, the screw drill also includes a top cover;

[0015] The top cover is located on the side of the stator housing near the second mounting hole and is used to connect to the drilling fluid pipeline to transport drilling fluid.

[0016] Preferably, the top cover, stator housing, rubber bushing and rotor are coaxially arranged.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] (I) The screw drill of the present invention is based on the dorsal hole morphology of earthworms and the rotor is biomimeticly designed. By setting a first through hole on the rotor, the first through hole is connected to the lubricant. After the drilling fluid enters the conjugate sealed cavity, it drives the rotor to rotate. During the rotation of the rotor, the lubricant enters the conjugate sealed cavity from the first through hole through the second through hole, thereby achieving the lubrication and drag reduction effect on the rotor and the rubber bushing. The screw drill of this embodiment has a simple structure and improves the service life of the rotor and the rubber bushing.

[0019] (II) The present invention sets a steel ball in the second through hole. When the steel ball is squeezed and rolled against the inner wall of the stator rubber bushing, it carries out lubricating fluid for lubrication and cooling, so as to simulate the automatic control opening and closing function of the earthworm dorsal hole.

[0020] (III) Based on the parallel vein structure of frangipani, the present invention makes a biomimetic design on the rubber bushing. Several spiral main vein through holes are set in the axial direction and several branch vein through grooves are set in the radial direction to connect the main vein through holes. The coolant can be fully filled in the main vein through holes and the branch vein through grooves, and can cool the rubber bushing in a timely and efficient manner during the operation of the motor.

[0021] (IV) The rotor of this invention adopts a central blind hole structure, which can accommodate lubricating fluid and reduce the weight of the screw motor. However, this structure is prone to buckling deformation under lateral loads. To solve this problem, foam steel is embedded in the first through hole. This not only ensures the flow channel of lubricating fluid, but also the foam steel has excellent impact resistance, energy absorption and vibration damping properties. When the screw motor is working, it can effectively absorb the vibration energy generated by pressure fluctuations and avoid rotor deformation and damage.

[0022] (V) This invention uses high-pressure drilling fluid to push lubricant into the foamed steel, requiring no additional equipment, and the implementation method is simple and reliable; moreover, the elastic bladder and the rotor are connected by threads, which can conveniently replenish lubricant into the elastic bladder, ensuring continuous and effective lubrication and cooling of the screw motor assembly. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of the screw drill bit of the present invention;

[0024] Figure 2 This is the present invention. Figure 1 AA section view;

[0025] Figure 3 This is a schematic diagram of the rotor structure of the present invention;

[0026] Figure 4 This is a cross-sectional view of the rotor of the present invention;

[0027] Figure 5 This is a schematic diagram of the structure of the rubber bushing of the present invention;

[0028] Figure 6 This is the invention Figure 5 CC section view;

[0029] Figure 7 This is a schematic diagram of the structure of the foamed steel of the present invention;

[0030] Figure 8 This is the inventionFigure 7 BB cross-sectional view.

[0031] The meanings of the labels in the diagram are as follows:

[0032] 1-Rotor, 2-Stator housing, 3-Rubber bushing, 4-Foam steel, 5-Elastic bladder, 6-Flow tube, 7-Top cover, 8-Steel ball, 9-Lubricant;

[0033] 11-First through hole, 12-Second through hole, 13-Rotor helical ridge, 14-Rotor helical groove;

[0034] 31-Main vein through-hole, 32-Branch vein through-groove;

[0035] 41-hole;

[0036] 61 - Through-flow hole;

[0037] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0038] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0039] The directional terms used in this document, such as “radial,” “axial,” and “circumferential,” correspond to the specific directions on the paper in the accompanying drawings or the corresponding directions in the space shown in the drawings.

[0040] Example:

[0041] A type of screw drill bit, such as Figures 1-7 As shown, the device includes a rotor 1, a stator housing 2, and a rubber bushing 3. The rubber bushing 3 is disposed inside the stator housing 2. The rubber bushing 3 has a first mounting hole along its axial direction. The rotor 1 is disposed inside the mounting hole and forms a conjugate sealing cavity with the mounting hole. The conjugate sealing cavity is connected to drilling fluid. The rotor 1 has a first through hole 11 along its axial direction and multiple second through holes 12 are provided at intervals along its radial direction in the axial direction. The second through holes 12 are used to connect the first through hole 11 and the conjugate sealing cavity. The first through hole 11 is connected to lubricant 9.

[0042] In this embodiment of the screw drill bit, a first through hole 11 is provided on the rotor 1, which is connected to the lubricant. After the drilling fluid enters the conjugate sealing cavity, it drives the rotor to rotate. During the rotation of the rotor 1, the lubricant enters the conjugate sealing cavity from the first through hole 11 through the second through hole 12, thereby achieving the lubrication and drag reduction effect on the rotor 1 and the rubber bushing 3. The screw drill bit of this embodiment has a simple structure and improves the service life of the rotor 1 and the rubber bushing 3.

[0043] The lubricant used in this embodiment is a grease with a large cone penetration made from a low-viscosity base oil, which can maintain good lubrication performance in a high-speed rotor environment.

[0044] As a preferred embodiment, each of the second through holes 12 is provided with a steel ball 8, which matches the second through hole 12 and can roll within the second through hole 12.

[0045] The purpose of including the steel ball 8 is to adaptively control the speed and flow rate of lubricant flowing out of the second through hole 12, thereby improving the uniformity of lubrication. Specifically, the steel ball 8 is rotatably and equidistantly installed within the second through hole 12. As the rotor 1 rotates, the steel ball 8 continuously undergoes compression and rolling friction with the inner wall of the stator rubber bushing 3, causing the steel ball 8 to roll within the second through hole 12, thereby carrying out the lubricant 9 to achieve lubrication and cooling of the rotor 1 and the stator rubber bushing 3.

[0046] As a preferred embodiment, the stator housing 2 is further provided with a second mounting hole, which communicates with the first mounting hole. An elastic bladder 5 is provided in the second mounting hole, and lubricant 9 is provided in the elastic bladder 5. The elastic bladder 5 communicates with the first through hole 11, and the elastic bladder 5 is connected to the rotor 1 by a thread, which allows for convenient replenishment of lubricant 9 into the elastic bladder 5, ensuring continuous and effective lubrication and cooling of the screw motor assembly.

[0047] The second mounting hole of the stator housing 2 is also provided with a flow pipe 6, which is connected to the conjugate sealing cavity. Drilling fluid enters the conjugate sealing cavity through the flow pipe 6.

[0048] Specifically, the high-pressure drilling fluid enters the flow pipe 6, squeezes the elastic bladder 5, and pushes the lubricant 9 inside the elastic bladder 5 to flow into the first through hole 11. Under the thrust of the elastic bladder 5, the lubricant inside the elastic bladder 5 enters the second through hole 12 of the rotor. The high-pressure drilling fluid enters the conjugate sealing cavity through the flow pipe 6 to drive the rotor to rotate.

[0049] As a preferred embodiment, the rubber bushing 3 has a plurality of main leaf vein through holes 31 arranged circumferentially along its axial direction, and a plurality of branch leaf vein through grooves 32 arranged axially at intervals along its radial direction. The branch leaf vein through grooves 32 communicate with the main leaf vein through holes 31, and supercoolant is pre-placed in the branch leaf vein through grooves 32 and the main leaf vein through holes 31.

[0050] The subcoolant pre-placed in the branch vein through-slots 32 and main vein through-holes 31 of the rubber bushing 3 continuously cools the rubber bushing 3, preventing thermal deformation and failure of the stator rubber bushing 3. The through-holes are sealed with plugs on both sides, allowing for periodic replacement of the subcoolant.

[0051] In this embodiment, the subcoolant is an ethylene glycol-based coolant, which has the characteristics of high boiling point, low foaming tendency, good viscosity-temperature performance, corrosion resistance and scale prevention, and is widely used with excellent cooling effect.

[0052] As a preferred embodiment, the screw drill bit further includes:

[0053] Foam steel 4 is disposed in the first through hole 11. The foam steel 4 body is provided with holes 41, which are connected to the first through hole 11.

[0054] The foamed steel 4 is formed by pressing and sintering metal powder, pore-forming agent and binder, and its matrix contains a large number of irregular pores 41. The foamed steel 4 is embedded in the first through hole 11 of the rotor and is fixedly connected to the rotor 1 by interference fit.

[0055] A first through hole 11 is provided inside the rotor, which can accommodate the lubricant 9 and also reduce the weight of the screw. However, this structure is prone to buckling deformation under lateral loads. To solve this problem, foam steel 4 is embedded in the first through hole. This not only ensures the flow channel of the lubricant 9, but also the foam steel 4 has excellent impact resistance, energy absorption and vibration damping properties. When the screw is working, it can effectively absorb the vibration energy generated by pressure fluctuations and prevent the rotor 1 from deforming and being damaged.

[0056] As a preferred embodiment, the rotor 1 is a screw, the rubber bushing 3 is threaded to match the rotor 1, and each main blade vein through hole 31 is arranged along the thread of the rubber bushing 3.

[0057] In a preferred embodiment, the outer circumference of the rotor 1 is characterized by alternating spiral ridges 13 and spiral grooves 14, with a second through hole 12 located on the spiral ridges 13. During rotor 1 rotation, the steel ball 8, which is movably fixed on the second through hole 12, can actively engage in rolling friction contact with the spiral grooves of the stator rubber bushing 3, thereby more smoothly carrying out the lubricant 9.

[0058] As a preferred embodiment, the subcoolant is an ethylene glycol-based coolant.

[0059] As a preferred embodiment, the screw drill tool further includes a top cover 7;

[0060] The top cover 7 is located on the side of the stator housing 2 near the second mounting hole and is used to connect with the drilling fluid pipeline to transport drilling fluid.

[0061] The usage process of this embodiment:

[0062] High-pressure drilling fluid enters the flow pipe 6 through the top cover 7, squeezing the elastic bladder 5 and pushing the lubricant 9 inside the elastic bladder 5 into the foam steel 4. The foam steel 4 is pre-filled with lubricant 9. Under the thrust of the elastic bladder 5, the lubricant inside the elastic bladder 5 and the pre-filled lubricant inside the foam steel 4 flow in the holes 41 of the foam steel 4 and enter the rotor second through hole 12; the lubricant 9 fills the holes 41 of the foam steel 4 and enters the second through hole 12.

[0063] Meanwhile, high-pressure drilling fluid enters the conjugate sealing cavity between rotor 1 and rubber bushing 3 through the through-flow hole 61 of the through-flow pipe 6, driving rotor 1 to rotate. During the rotation of rotor 1, steel ball 8 and the inner wall of rubber bushing 3 are squeezed and rolled, causing steel ball 8 to roll in the second through hole 12, thereby carrying out lubricant 9 to achieve lubrication and cooling of rotor 1 and stator rubber bushing 3. At the same time, the supercoolant filled in the main blade vein through hole 31 and the branch blade vein through groove 32 continuously cools rubber bushing 3.

Claims

1. A screw drill bit, comprising a rotor (1), a stator housing (2), and a rubber bushing (3), wherein the rubber bushing (3) is disposed within the stator housing (2), and a first mounting hole is provided along the axial direction of the rubber bushing (3), and the rotor (1) is disposed within the first mounting hole and forms a conjugate sealing cavity with the first mounting hole, the conjugate sealing cavity being connected to drilling fluid, characterized in that, The rotor (1) has a first through hole (11) in its axial direction and a plurality of second through holes (12) are provided in its radial direction at intervals in the axial direction. The second through holes (12) are used to connect the first through hole (11) and the conjugate sealing cavity. The first through hole (11) is connected to the lubricant (9). Each of the second through holes (12) is provided with a steel ball (8), which is matched with the second through hole (12) and can roll within the second through hole (12); The stator housing (2) is also provided with a second mounting hole, which is connected to the first mounting hole. An elastic bladder (5) is provided in the second mounting hole, and lubricant (9) is provided in the elastic bladder (5). The elastic bladder (5) is connected to the first through hole (11). The second mounting hole is also provided with a flow pipe (6), which is connected to the conjugate sealing cavity. Drilling fluid enters the conjugate sealing cavity through the flow pipe (6). The rubber bushing (3) has multiple main leaf vein through holes (31) arranged circumferentially along its axial direction, and multiple branch leaf vein through grooves (32) arranged axially at intervals along its radial direction. The branch leaf vein through grooves (32) are connected to the main leaf vein through holes (31), and supercooling agents are pre-placed in the branch leaf vein through grooves (32) and the main leaf vein through holes (31). The screw drill also includes: foam steel (4), which is disposed in the first through hole (11). The foam steel (4) body is provided with holes (41), which are connected to the first through hole (11).

2. The screw drill bit as described in claim 1, characterized in that, The rotor (1) is a screw, and the rubber bushing (3) is threaded to match the rotor (1). The main blade vein through holes (31) are arranged along the thread of the rubber bushing (3).

3. The screw drill bit as described in claim 2, characterized in that, The outer periphery of the rotor (1) is formed by alternating rotor spiral ridges (13) and rotor spiral grooves (14), and the second through hole (12) is provided on the rotor spiral ridges (13).

4. The screw drill bit as described in claim 1, characterized in that, The supercoolant used is ethylene glycol-based coolant.

5. The screw drill bit as described in claim 3, characterized in that, The screw drill also includes a top cover (7); The top cover (7) is located on the side of the stator housing (2) near the second mounting hole and is used to connect with the drilling fluid pipeline to transport drilling fluid.

6. The screw drill bit as described in claim 5, characterized in that, The top cover (7), stator housing (2), rubber bushing (3) are coaxially arranged with the rotor (1).

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