Power head rotation control system, control method thereof and drilling machine

Abstract

The invention discloses a power head rotation control system, a control method thereof and a drilling machine. The system comprises a pump and a main valve which are used for providing pressure oil for the system; the first pressure valve is arranged at the outlet end of the pump and used for limiting system oil pressure when oil is supplied to the power head motor or supplemented to the power head motor; and the control valve group is arranged between an oil outlet A1 and an oil return port B1 of the main valve and is used for conducting an A port oil way and a B port oil way of the power head motor when the system pressure exceeds a preset high threshold value so as to control the system pressure or realize system energy release. The torque release of the power head can be realized after the drilling machine top driving power head rotates clockwise, particularly when the power head stops suddenly or shackles after fast clockwise rotation, a power head motor is prevented from being damaged due to air suction, meanwhile, the system pressure can be buffered when the power head suddenly operates or the instantaneous pressure of a rotating system is too high, and the reliability of the drilling machine top driving power head is improved. And the working safety of the power head is ensured.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery technology, and more specifically, relates to a power head rotation control system and its control method, as well as a drilling rig. Background Technology

[0002] Deep well drilling rigs are specialized equipment for shallow resource extraction. They are mainly used for drilling and extracting resources such as coalbed methane, shale gas, shallow oil, geothermal energy, and groundwater. They have the advantages of large hole diameter and high drilling efficiency, and are also used in special occasions such as mine rescue and gas extraction.

[0003] The main working principle of the drilling rig is as follows: The top drive head moves up and down on the drilling rig under the action of hydraulic cylinders and wire ropes. Simultaneously, the hydraulic motor drives the top drive head to rotate the drill bit, drill rod, and other drilling tools, cutting and breaking the rock strata to achieve rock drilling and hole formation. An air compressor or mud pump, connected to the air / mud manifold, uses pressure to expel the rock debris from the well to the surface. When a new drill rod connected to the power head is drilled down, the upper and lower clamps of the uncoupling device clamp the drill collar at the front of the power head and the downhole drill rod, respectively. The reverse rotation of the upper clamp breaks the connecting threads. Then, the counterclockwise rotation of the power head disconnects the drill rod connected to the downhole. The power head quickly moves to the top of the drilling rig and then connects to the new drill rod. Drilling depths range from several hundred meters to over 3000 meters.

[0004] The applicant has discovered the following problems with existing drilling rigs during construction: 1. The top drive head drives the downhole drill pipe and other drilling tools to rotate clockwise. Especially when it rotates rapidly and then suddenly stops, the resistance of the downhole drill pipe and other drilling tools is very large. The downhole drill pipe and other drilling tools connected to the top drive head are hundreds of meters or even two or three thousand meters long. At this time, the downhole drill pipe and other drilling tools drive the power head to rotate counterclockwise (reverse rotation). The oil port of the top drive head sucks in air, which causes the motor to overheat and be damaged. 2. When the uncoupling device is used to disconnect the drill pipe connected to the top drive head, the power head motor is stationary. The lower clamp of the uncoupling device clamps the upper end of the drill pipe at the wellhead, and the upper clamp clamps the drill pipe or drill collar at the front of the power head. The rotating cylinder drives the upper clamp to rotate in the opposite direction (counterclockwise) in order to disconnect the threads connecting the drill pipe. At this time, the motor oil port is sucked into the air, which reduces the life of the internal components of the motor or causes damage. 3. When the power head suddenly starts running or the pressure of the rotating system suddenly increases, there is no buffer component, which leads to a reduction in the lifespan of hydraulic system components. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned shortcomings by providing a power head rotation control system, its control method, and a drilling rig. This system not only enables the release of torque from the power head when it suddenly stops or is uncoupled after the top drive head of the drilling rig rotates clockwise, especially after the power head has rotated rapidly clockwise, thus preventing the power head motor from losing its lifespan or being damaged due to cavitation, but also buffers system pressure when the power head suddenly starts or the rotation system experiences excessively high instantaneous pressure, ensuring the safe operation of the power head.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a power head rotation control system, including a pump and a main valve for providing pressurized oil to the system; Pressure valve 1, located at the pump outlet, is used to limit the system oil pressure when supplying or replenishing oil to the power head motor. The control valve assembly, located between the oil outlet A1 and the oil return B1 of the main valve, is used to open the oil circuits A and B of the power head motor when the system pressure exceeds a preset high threshold, in order to control the system pressure or release system energy.

[0007] Furthermore, the control valve assembly includes pressure valve two, pressure valve three, and solenoid valve one; The pressure valve 2 is used to open the inlet and return oil circuits to control the system pressure when the oil pressure at port A of the power head motor exceeds a preset high threshold. The pressure valve three is used to open the inlet and return oil circuits to control the system pressure when the oil pressure at port B of the power head motor exceeds a preset high threshold. The solenoid valve is used to open ports A and B of the power head motor to release system energy.

[0008] Furthermore, the P2 port of the pressure valve is connected to the A port of the power head motor through the first check valve and to the B port of the power head motor through the second check valve.

[0009] Furthermore, the P2 port of the pressure valve one is connected to the displacement control port of the power head motor through the solenoid valve two.

[0010] Furthermore, the P1 port of the second solenoid valve is connected to the first check valve, the S port of the second check valve, and the P2 port of the first pressure valve, while the T port of the second solenoid valve is connected to the oil tank.

[0011] Furthermore, the P1 port of the pressure valve is connected to the P port of the pump, and the T port of the pressure valve is connected to the oil tank.

[0012] Furthermore, the A1 port of the main valve is connected to solenoid valve one, check valve one, pressure valve two, pressure valve three and the A port of the power head motor via pipelines; the B1 port of the main valve is connected to solenoid valve one, check valve two, pressure valve two, pressure valve three and the B port of the power head motor via pipelines.

[0013] Furthermore, it also includes switch one, switch two, solenoid valve one coil and solenoid valve two coil. Switch one and switch two are used to control the energization and de-energization of solenoid valve one coil and solenoid valve two coil, thereby controlling the commutation of solenoid valve one and solenoid valve two.

[0014] Furthermore, switch one is a self-resetting push-button switch, and switch two is a self-locking push-button switch. One end of switch one and switch two are connected to the positive terminal of the power supply via a wire, and the other end is connected to the positive terminals of the coils of solenoid valve one and solenoid valve two, respectively. The negative terminals of the coils of solenoid valve one and solenoid valve two are connected to the negative terminal of the power supply.

[0015] In a second aspect, the present invention also provides a control method for the power head rotation control system described in the first aspect, comprising: When the oil pressure output from the main valve to the power head motor is lower than the preset low threshold, the oil output from the pump is output to the power head motor through pressure valve 1 for oil replenishment. When the oil pressure output from port A1 of the main valve to port A of the power head motor is higher than the preset high threshold, ports A and B of pressure valve three are connected, allowing some high-pressure oil to flow from port B of pressure valve three into port B1 of the main valve; when the oil pressure output from port B1 of the main valve to port B of the power head motor is higher than the preset high threshold, ports A and B of pressure valve two are connected, allowing some high-pressure oil to flow from port A of pressure valve two into port A1 of the main valve. When the main valve stops running, the power head motor is passively rotated counterclockwise, which opens the A and B ports of solenoid valve one, thereby realizing the release of system energy. When the stratum is hard and the power head motor needs to rotate at high speed, the oil output by the pump is output to the G port of the power head motor through pressure valve one and solenoid valve two.

[0016] Furthermore, when the oil pressure output from the main valve to the power head motor is lower than a preset low threshold, it is divided into port A and port B. When the oil pressure output from port A1 of the main valve to port A of the power head motor is lower than the preset low threshold, the oil output by pump 10 flows out through pressure valve one to check valve one, and then flows out through check valve one to port A of the power head motor, thereby replenishing the oil to the power head motor. When the oil pressure output from port B1 of the main valve to port A of the power head motor is lower than the preset low threshold, the oil output by pump 10 flows out through pressure valve one to check valve two, and then flows out through check valve two to port B of the power head motor, thereby replenishing the oil to the power head motor.

[0017] Thirdly, the present invention also provides a drilling rig equipped with the power head rotation control system described in the first aspect.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The power head rotation control system and control method described in this invention can not only release the torque of the power head when it suddenly stops or is unhooked after the top drive head of the drilling rig rotates clockwise, especially when the power head rotates rapidly clockwise, thus preventing the power head motor from being damaged due to cavitation, but also buffer the system pressure when the power head suddenly runs or the instantaneous pressure of the rotation system is too high, thus ensuring the working safety of the power head. Attached Figure Description

[0019] Figure 1 A schematic diagram of the hydraulic control structure of a power head rotation control system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the electrical control principle of the power head rotation control system described in the embodiment; In the diagram: 1. Pressure valve one; 2. Solenoid valve one; 3. Check valve one; 4. Check valve two; 5. Pressure valve two; 6. Pressure valve three; 7. Oil tank; 8. Power head motor; 9. Solenoid valve two; 10. Pump; 11. Main valve; 12. Switch one; 13. Switch two; 14. Solenoid valve one coil; 15. Solenoid valve two coil. Detailed Implementation

[0020] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings and specific examples.

[0021] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0022] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0023] The singular forms “a” and “the” used in this specification and the appended claims include plural references unless otherwise expressly stated herein. It should be noted that the term “or” is generally used to mean “and / or” unless otherwise expressly stated herein.

[0024] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] For ease of understanding, the drilling rig and its main working process described in this invention are explained below: The drilling rig mainly consists of a traveling chassis, working devices (including the drilling tower, top drive head, tool winch, uncoupler, and mud manifold), and power, hydraulic, and electrical systems. The operator's cab is the primary operating position for the operator during drilling operations. The top drive head moves up and down on the drilling tower under the action of hydraulic cylinders and wire ropes. Simultaneously, a hydraulic motor drives the top drive head to rotate the drill bit, drill rod, and other drilling tools, cutting and breaking the rock formation to achieve rock drilling and hole formation. An air compressor or mud pump, connected to the air / mud manifold, uses pressure to expel the rock debris from the well to the surface. After a single drill rod is drilled, a new drill rod is connected from the top, with a maximum drilling depth of nearly 4000 meters. Winches, uncouplers, and rod changers work together to enable rapid loading and unloading of drill rods.

[0026] Operating the "Power Head Rotation" handle forward will rotate the power head clockwise, and operating the handle backward will rotate it counterclockwise. The greater the range of motion of the handle, the faster the power head rotates. Rotation stops when the handle returns to its original position. Operating the "Power Head Feed" handle forward will move the power head upward, and operating the handle backward will move it downward. The greater the range of motion of the handle, the faster the power head moves up and down. Up and down movement stops when the handle returns to its original position.

[0027] Example 1 This embodiment provides a power head rotation control system, the hydraulic control structure of which is as follows: Figure 1 As shown, it includes a pump 10 and a main valve 11 that provide pressurized hydraulic fluid to the system, a power head motor 8 that provides rotational power to the top drive head, and an oil tank 7 for storing hydraulic fluid in the hydraulic system.

[0028] In this embodiment, the power head motor 8 is a two-point variable motor. Its G port is the displacement control oil port. When pressurized oil flows into the G port, the motor rotates at high speed, thereby driving the top drive head to rotate at high speed. When oil enters the motor through the A port and exits through the B port, the motor rotates clockwise to realize the normal drilling of the drilling rig or the connection of the drill rod. When oil enters the motor through the B port and exits through the A port, the motor rotates counterclockwise to realize the disassembly of the drill rod of the drilling rig.

[0029] In this embodiment, it also includes a pressure valve 1 for limiting system oil pressure, a pressure valve 5 for controlling system pressure, a pressure valve 6 for controlling system pressure, and a solenoid valve 2 for releasing system energy; it also includes a check valve 3 and a check valve 4 for ensuring one-way flow of oil.

[0030] like Figure 1 As shown, in this embodiment, the oil inlets of check valve 3 and check valve 4 are connected to port S, and the oil outlets of check valve 3 and check valve 4 are connected to ports A and B respectively. The ports A of solenoid valve 2, check valve 3, pressure valve 5, and pressure valve 6 are connected together through pipelines, and the ports B of solenoid valve 2, check valve 4, pressure valve 5, and pressure valve 6 are connected together through pipelines.

[0031] The A1 port of the main valve 11 is connected to the A port of the solenoid valve 2, check valve 3, pressure valve 5, pressure valve 6 and motor 8 through a pipeline. The B1 port of the main valve 11 is connected to the B port of the solenoid valve 2, check valve 4, pressure valve 5, pressure valve 6 and motor 8 through a pipeline.

[0032] The T port and G port of the motor 8 are respectively connected to the oil tank 7 and the A2 port of the second solenoid valve 9 through pipelines. The P1 port and T port of the second solenoid valve 9 are respectively connected to the one-way valve 3, the S port of the one-way valve 4, the P2 port of the pressure valve 1, and the oil tank 7. The P1 port and T port of the pressure valve 1 are respectively connected to the P port of the pump 10 and the oil tank 7.

[0033] The power head rotation control system described in this embodiment also includes electrical components, such as... Figure 2 As shown, the system includes switch 12, switch 2 13, solenoid valve 1 coil 14, and solenoid valve 2 coil 15. Switch 12 is a self-resetting push-button switch, and switch 2 13 is a self-locking push-button switch. Switches 12 and 2 13 control the energization or de-energization of solenoid valve 1 coil 14 and solenoid valve 2 coil 15, thereby controlling the switching of solenoid valve 1 2 and solenoid valve 2 9. The positive terminal of the DC 24V power supply is connected to terminal a of switch 12 and switch 2 13 via a wire. Terminal b of switch 12 and switch 2 13 is connected to the positive terminals of coil 1 14 and coil 2 15, respectively. The negative terminals of coil 1 14 and coil 2 15 are connected to the negative terminal of the power supply.

[0034] Example 2 This embodiment provides a control method for the power head rotation control system described in Embodiment 1. Its specific working process and principle are as follows: When the drilling rig is working, by pushing the rotating handle forward at a certain angle, the pressurized oil output from port A1 of the main valve 11 flows into port A of the power head motor 8 and out through port B of the power head motor 8 to port B1 of the main valve 11. The power head motor 8 drives the top drive head to rotate clockwise. The lower end of the top drive head rotates clockwise through the drill collar connected to the drill rod and other drilling tools, cutting and breaking the rock strata. At the same time, by pushing the feed handle backward at a certain angle, the top drive head moves downward so that the top drive head drives the drill rod to drill downward. If the oil pressure output from port A1 of main valve 11 to port A of power head motor 8 is lower than the set value (e.g., 250 bar), then the oil output from port P of pump 10 flows into port P1 of pressure valve-1 (pressure can be set as needed), flows out through port P2 to port S of check valve-3, and then flows out through port A of check valve-3 to port A of power head motor 8, thus replenishing oil to power head motor 8 and preventing the motor from being damaged by cavitation due to low system pressure. Since the replenishment pressure to power head motor 8 cannot be too high, the pressure oil output from pump 10 is depressurized by pressure valve-1. When the formation is hard, the top drive head needs to drive the drill pipe and other drilling tools to rotate rapidly. At this time, when switch 13 is pressed, the a end of switch 13 is connected to the b end, the coil 15 of solenoid valve 2 is energized, and solenoid valve 9 is reversed. At this time, the oil output from the P port of pump 10d flows in through the P1 port of pressure valve 1, flows out through the P2 port to the P1 port of solenoid valve 9, and flows out through the A2 port of solenoid valve 9 to the G port of the power head motor 8. The power head motor 8 rotates rapidly, and the downhole drill pipe and other drilling tools rotate rapidly in order to quickly cut the harder formation.

[0035] After a drill pipe penetrates the formation, a new drill pipe is connected via a tool winch, unlatcher, and power head. Due to the depth of the borehole, the top drive head connects dozens to hundreds of underground drill pipes via drill collars. When the rotary handle is suddenly pushed forward, the pressure of the system rotating clockwise suddenly increases due to the significant resistance from the downhole rock, soil, or mud. This means the oil pressure output from port A1 of the main valve 11 to port A of the power head motor 8 suddenly increases, potentially damaging the rotary power head motor 8. At this time, ports A and B of pressure valve 6 are connected (the connection pressure can be set as needed), and some high-pressure oil flows from port B of pressure valve 6 into port B1 of the main valve 11. Alternatively, if the oil pressure output from port A1 of the main valve suddenly increases due to other reasons, it may also damage the rotary power head motor 8 or the hydraulic system. In this case, ports A and B of pressure valve 6 are connected, and some high-pressure oil flows from port B of pressure valve 6 into port B1 of the main valve 11, ensuring the stability of the system pressure and thus ensuring the safe operation of the motor.

[0036] When the top drive head needs to connect a new drill pipe, or when it needs to rotate clockwise for some reason and suddenly stops, due to the large number of drill pipes connected downhole and the high resistance, even though the drive head rotation handle has returned to the neutral position, the downhole drill pipes and other drilling tools will rotate counterclockwise (reverse rotation). At this time, the A1 port of the main valve 11 has stopped outputting oil to the drive head motor 8, and the B1 port has stopped returning oil. The drive head motor 8 then passively rotates counterclockwise, and a cavitation phenomenon occurs at the B port of the drive head motor 8. At this moment, pressing switch 12 connects terminals a and b of switch 12, energizing the coil 14 of solenoid valve 1. Solenoid valve 2 reverses direction, connecting terminals A and B of solenoid valve 2, which in turn connects terminals A and B of the drive head motor 8. This allows for rapid energy release from the drive head motor 8 and the internal system, achieving the purpose of protecting the hydraulic system and the drive head motor 8.

[0037] After the drill pipe connected to the top drive head is drilled downhole, the threaded connection between the drill collar at the front of the drive head and the downhole drill pipe needs to be disconnected to connect a new drill pipe. After drilling is completed, the previously connected drill pipe needs to be disassembled. At this time: ① Operate the "uncoupling device" control handle up or down to adjust the height of the uncoupling device so that the upper and lower clamps can clamp the two connected drill pipes respectively; ② Operate the "uncoupling device" control handle to the left to make the uncoupling device swing inward until the center of the clamp is aligned with the center of the drill pipe; ③ Simultaneously operate the lower end of the "uncoupling device upper clamp" and "uncoupling device lower clamp" rocker switches to make the upper and lower clamps hold the upper and lower drill pipes respectively; ④ Operate the lower or upper end of the "up / uncoupling" rocker switch to perform the uncoupling or uncoupling operation. If the upper drill rod cannot be unhooked or tightened in one go, operate the upper end of the "Unhooking Device Upper Clamping" rocker switch to loosen the drill rod, press the upper end of the "Up / Unhooking" rocker switch, and after the unhooking cylinder rotates in the opposite direction, the unhooking device upper clamping cylinder will tighten the drill rod again. Repeat the unhooking / uphooking operation until the hook between the two drill rods breaks open or tightens.

[0038] Since the power head is stationary at this time, and the drill pipe below is also stationary, clamped by the lower clamp of the uncoupling device, the upper clamp of the uncoupling device clamps the upper drill pipe or the drill collar in front of the power head and rotates counterclockwise to uncouple. At this time, the stationary top drive motor 8 is passively rotated counterclockwise, resulting in very low pressure between port B1 of the main valve 11 and port B of the power head motor 8. The power head motor 8 is very prone to cavitation (no lubrication) and thus its lifespan is reduced or it is damaged. At this time, the oil output from port P of pump 10 flows in through port P1 of pressure valve 1, flows out through port P2 to port S of check valve 3, and flows out through port B of check valve 3 to the power head. Port B of motor 8 provides oil replenishment to the power head motor 8, preventing damage due to low system pressure. Since the replenishment pressure to the power head motor 8 cannot be too high, the pressure oil output from pump 10 is depressurized via pressure valve 1. Simultaneously, pressing switch 12 connects terminals a and b, energizing coil 14 of solenoid valve 1. This causes solenoid valve 2 to switch direction, connecting ports A and B, which in turn connects ports A and B of the power head motor 8. This allows for rapid energy release from the power head motor 8 and the hydraulic system, thus protecting the system and the power head motor 8.

[0039] Operating the handle backwards rotates the power head counterclockwise. The greater the range of the handle movement, the faster the power head rotates. At this time, the oil output from port B1 of the main valve 11 flows into port B of the power head motor 8, and then flows out from port A of the power head motor 8 back to port A1 of the main valve. The power head motor 8 drives the top drive head to rotate counterclockwise. If the oil pressure output from port B1 of the main valve 11 to port B of the power head motor 8 is lower than the set value (e.g., 250 bar), At this time, the oil output from port P of pump 10 flows into port P1 of pressure valve 1, flows out through port P2 to port S of check valve 4, and flows out through port B of check valve 4 to port B of power head motor 8, thus replenishing the oil to power head motor 8 and preventing power head motor 8 from being damaged by cavitation due to low system pressure. Since the replenishment pressure to power head motor 8 cannot be too high, the pressure oil output from pump 10 plays a pressure reduction role through pressure valve 1. In addition, if the oil pressure output from port B1 of main valve 11 suddenly increases due to other reasons, it may also damage the rotating power head motor 8 or the hydraulic system. At this time, port B of pressure valve 5 is connected to port A, and some high-pressure oil flows from port B of pressure valve 5 into port A1 of main valve, thereby ensuring the safe operation of power head motor 8. When the handle is reset, the rotation of power head motor 8 stops.

[0040] Example 3 This embodiment provides a drilling rig, which is equipped with the power head rotation control system described in Embodiment 1.

[0041] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and principles of the described embodiments, and these modifications and variations should also be considered within the scope of protection of the present invention.

Claims

1. A powerhead rotation control system, characterized by, Pump (10) and main valve (11) for providing pressure oil for the system; Pressure valve one (1) arranged at the outlet of pump (10) for limiting the system pressure when supplying or supplementing oil to power head motor (8); Control valve group arranged between A1 port and B1 port of main valve (11) for conducting A port and B port of power head motor (8) to control the system pressure or release the system energy when the system pressure exceeds the preset high threshold.

2. The head rotation control system according to claim 1, characterized by, The control valve group comprises pressure valve two (5), pressure valve three (6) and electromagnetic valve one (2); The pressure valve two (5) is used for conducting the inlet oil path and the return oil path to control the system pressure when the A port oil path pressure of power head motor (8) exceeds the preset high threshold; The pressure valve three (6) is used for conducting the inlet oil path and the return oil path to control the system pressure when the B port oil path pressure of power head motor (8) exceeds the preset high threshold; The electromagnetic valve one (2) is used for conducting the A port and the B port of power head motor (8) to release the system energy when the main valve (11) stops working.

3. The head rotation control system according to claim 2, characterized by, The P2 port of pressure valve one (1) is connected with the A port of power head motor (8) through one-way valve one (3) and connected with the B port of power head motor (8) through one-way valve two (4).

4. The head rotation control system according to claim 3, characterized by The P2 port of pressure valve one (1) is connected with the displacement control port of power head motor (8) through electromagnetic valve two (9).

5. The head rotation control system of claim 4, wherein The P1 port of electromagnetic valve two (9) is connected with the S port of one-way valve one (3) and one-way valve two (4) and the P2 port of pressure valve one (1), and the T port of electromagnetic valve two (9) is connected with oil tank (7).

6. The head rotation control system of claim 3, wherein The P1 port of pressure valve one (1) is connected with the P port of pump (10), and the T port of pressure valve one (1) is connected with oil tank (7).

7. The head rotation control system of claim 3, wherein The A1 port of main valve (11) is connected with electromagnetic valve one (2), one-way valve one (3), pressure valve two (5), pressure valve three (6) and the A port of power head motor (8) through pipelines, and the B1 port of main valve (11) is connected with electromagnetic valve one (2), one-way valve two (4), pressure valve two (5), pressure valve three (6) and the B port of power head motor (8) through pipelines.

8. The head rotation control system of claim 4, wherein Switch one (12) and switch two (13) are used for controlling the power-on and power-off of electromagnetic valve one coil (14) and electromagnetic valve two coil (15) to control the commutation of electromagnetic valve one (2) and electromagnetic valve two (9).

9. A control method of the head rotation control system according to any one of claims 1 to 8, characterized by, Comprise: When the oil pressure output from main valve (11) to power head motor (8) is lower than the preset low threshold, the oil output from pump (10) is output to power head motor (8) for supplementing oil through pressure valve one (1); When the oil pressure of the A1 port of the main valve (11) output to the A port of the power head motor (8) is higher than the preset high threshold, the A port and the B port of the pressure valve three (6) are conducted, and part of the high pressure oil flows into the B1 port of the main valve (11) from the B port of the pressure valve three (6); when the oil pressure of the B1 port of the main valve (11) output to the B port of the power head motor (8) is higher than the preset high threshold, the A port and the B port of the pressure valve two (5) are conducted, and part of the high pressure oil flows into the A1 port of the main valve (11) from the A port of the pressure valve two (5); When the main valve (11) stops running and the power head motor (8) is passively counterclockwise rotated, the A port and the B port of the electromagnetic valve one (2) are conducted, so that the system energy is released; When the formation is relatively hard and the power head motor (8) needs to rotate at high speed, the oil output by the pump (10) is output to the G port of the power head motor (8) through the pressure valve one (1) and the electromagnetic valve two (9).

10. A rig characterized by, The drilling rig is provided with the power head rotation control system of any one of claims 1 to 8.

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