Control tool for screw drill

Abstract

The control tool comprises an inner shaft and a shell, the upper end of the shell is used for being connected with an upper drill column, a transmission control part is arranged between the inner shaft and the shell, and the transmission control part is used for transmitting the torque of the upper drill column to the tool face of the screw drill so as to smoothly transmit bit pressure. The counter-torque balancing device is used for balancing the counter-torque acting on the shell of the screw drill, so that an upper drill column can rotate normally; the lower end of the inner shaft is used for being connected with an MWD measuring nipple. According to the embodiment of the invention, the friction torque can be regulated and controlled to balance the reaction torque of the shell of the screw drill; the upper drill column and the lower screw drill can rotate in the whole process to eliminate the conditions such as backing pressure, and the purposes of reducing friction, reducing resistance and increasing speed are achieved; when the screw drill performs directional sliding drilling, the friction torque can be controlled to balance the reaction torque of the shell of the screw drill, so that the rotation angle of the tool face of the screw drill is effectively controlled, and the controllability of a well track is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil drilling tools, and particularly relates to a control tool for a positive displacement motor (PDM). Background Art

[0002] Currently, PDMs are widely used in drilling operations of complex structure wells such as deep wells, ultra-deep wells, directional wells, extended reach wells, and long horizontal wells. A PDM is a commonly used downhole motor drill in the drilling process of new and old oil and gas fields.

[0003] When the PDM is in the process of directional sliding drilling, the drilling fluid drives the rotor of the PDM to drive the drill bit to rotate clockwise to generate torque to break the rock, and at the same time, a counter-torque in the counterclockwise direction is generated on the stator of the PDM. The counter-torque acts on the outer shell of the PDM; the outer shell of the PDM is connected to the upper drill string, and the counter-torque of the PDM will cause the PDM and the upper drill string to rotate counterclockwise by a certain angle, which will cause the angle of the tool face to change and deviate, thus affecting the control of the wellbore trajectory. Therefore, in order to offset the counter-torque of the PDM to ensure that the tool face of the PDM is in a stable state, the upper drill string must be stopped from rotating; the stop of the upper drill string will cause a huge axial friction between the upper drill string and the wellbore wall, especially in the drilling process of long horizontal section horizontal wells and extended reach wells, which will cause very serious sticking pressure, thereby resulting in unsmooth transfer of the drilling pressure, low mechanical drilling rate, and greatly reducing the drilling efficiency of the PDM. In addition, the common method for adjusting the tool face angle of a conventional PDM is generally: adjusting the rotation angle of the upper drill string according to actual needs and observing the tool face angle through a measurement-while-drilling instrument to make the adjusted working face angle equal to the expected angle. This method has the disadvantage of long time consumption, and because of the existence of sticking pressure, the drilling pressure and torque are difficult to be transmitted to the drill bit, so the adjustment of the tool face angle is also difficult.

[0004] In the prior art, the disadvantages of sticking pressure and inability to independently control the tool face seriously restrict the application of conventional PDMs in complex drilling processes. Summary of the Invention

[0005] In order to solve all or part of the above problems, the purpose of the present invention is to provide a control tool for a PDM. The control tool for a PDM of the present invention can transmit the torque of the upper drill string to the tool face of the PDM to smoothly transmit the drilling pressure, and can balance the counter-torque acting on the outer shell of the PDM, so that the upper drill string can rotate normally.

[0006] According to an aspect of the present invention, a control tool for a positive displacement motor is provided, including an inner shaft and a housing. The upper end of the housing is used to connect with the upper drill string. A transmission control part is arranged between the inner shaft and the housing. The transmission control part is used to transfer the torque of the upper drill string to the tool face of the positive displacement motor to smoothly transfer the drilling pressure, and to balance the reaction torque acting on the outer shell of the positive displacement motor, so that the upper drill string can rotate normally. The lower end of the inner shaft is used to connect with an MWD measurement sub.

[0007] Further, the transmission control part includes a buffer spring sleeved on the inner shaft and limited on the inner shaft. A friction assembly is limited between the inner shaft above the buffer spring and the housing. A rotating cavity is arranged above the friction assembly. A moving spline sleeve is sleeved on the inner shaft above the rotating cavity. The moving spline sleeve can transfer the torque of the housing to the inner shaft, and when the moving spline sleeve moves to the rotating cavity, the moving spline sleeve cannot transfer the torque of the housing to the inner shaft.

[0008] The upper end of the inner shaft is fixedly and sealingly connected with a support end. The lower end of the inner shaft is sealingly connected with the housing. A hydraulic piston is arranged in the sealed hydraulic cavity formed by the inner shaft, the support end and the housing. The upper end of the moving spline sleeve is fixedly connected with the hydraulic piston. A first return spring is arranged between the moving spline sleeve and the hydraulic piston. The lower end of the first return spring is limited by the shoulder of the housing.

[0009] The support end is fixedly and sealingly connected with an external structure. A circuit board protection chamber is fixedly and sealingly arranged between the support end and the external structure. A drive assembly is fixedly arranged on the support end. The drive assembly is located in the inner cavity formed by the support end, the external structure and the circuit board protection chamber. The drive assembly is connected with a hydraulic control unit. The hydraulic control unit is used to supply high-pressure oil to the high-pressure oil cavity above the hydraulic piston.

[0010] The friction assembly is used to generate a friction torque under the action of the hydraulic piston.

[0011] Further, a locking piston is hermetically arranged in the sealed hydraulic cavity. The locking piston is located between the support end and the hydraulic piston. A high-pressure oil cavity is formed between the locking piston and the hydraulic piston. The cavities on the side of the locking piston away from the hydraulic piston and on the side of the hydraulic piston away from the locking piston are both low-pressure oil cavities. A second return spring is arranged between the locking piston and the support end. A locking block is arranged in the radial movement hole of the hydraulic piston. When the hydraulic piston moves axially, the locking block moves radially along the inclined plane of the chute on the outer surface of the inner shaft. After the locking piston moves to the unlocking position in the direction of the low-pressure oil cavity away from the hydraulic piston, the locking piston is disengaged from the locking block.

[0012] Further, the lower end of the buffer spring is limited by a shoulder arranged on the inner shaft, and the upper end of the buffer spring is limited by a first elastic retaining ring fixed on the inner shaft.

[0013] The friction assembly includes a plurality of rotor friction plates. A plurality of the rotor friction plates are all arranged above the buffer spring. A plurality of the rotor friction plates are key-connected to the inner shaft. A stator friction plate is arranged between adjacent two of the rotor friction plates. A plurality of the stator friction plates are key-connected to the housing. The lowermost rotor friction plate is limited by a support ring between it and the buffer spring. The uppermost rotor friction plate is limited by a second elastic retaining ring fixed on the inner shaft. The rotating cavity is arranged above the uppermost rotor friction plate.

[0014] Further, the external structure includes a protection cylinder arranged outside the support end. The support end is fixedly and hermetically connected to the protection cylinder. The protection cylinder is fixedly and hermetically connected to the upper end of the protection chamber. The circuit board protection chamber is arranged in the inner cavity formed by the support end and the upper end of the protection chamber. The circuit board protection chamber is key-connected to both the support end and the upper end of the protection chamber, and is hermetically arranged between the circuit board protection chamber and the support end and the upper end of the protection chamber.

[0015] Further, a pressure sensor is fixedly and hermetically connected to the upper end of the protection chamber. A mud pressure taking cavity, a mud channel, and a mud pressure taking hole that are sequentially communicated are formed on the upper end of the protection chamber. The pressure sensor extends into the mud pressure taking hole. The pressure sensor is used to measure the mud pressure in the central flow channel of the upper end of the protection chamber. A mud sieve plate is fixed at the mud pressure taking cavity through an elastic retaining ring.

[0016] Further, a first thrust bearing group is sleeved on the upper end head of the protection bin. The lower end of the inner ring of the first thrust bearing group is limited by a shoulder provided on the upper end head of the protection bin. A first fixing ring is threadedly connected to the upper end head of the protection bin, and the first fixing ring is used to limit the upper end of the inner ring of the first thrust bearing group. The upper end of the housing is threadedly connected with an upper joint, and the housing and the upper joint are fixedly connected. The upper joint is used to be connected with the upper drill string, and the upper joint is used to limit the upper end of the outer ring of the first thrust bearing group. The lower end of the outer ring of the first thrust bearing group is limited by a step provided on the housing.

[0017] Further, the drive assembly includes a motor reduction assembly. The motor reduction assembly is fixed on a motor reduction assembly fixing frame. The output shaft of the motor reduction assembly is connected to the hydraulic control unit through a coupling. The cable of the motor reduction assembly is connected to a corresponding joint of a first electrical sealing joint. The first electrical sealing joint is fixedly and sealingly connected to a first plug. The first plug is fixedly and sealingly connected to a motor reduction assembly protection cylinder. One end of the motor reduction assembly protection cylinder is fixedly and sealingly connected to a coupling nipple. The other end of the coupling nipple is fixedly and sealingly connected to the support end head.

[0018] Further, the hydraulic control unit includes a hydraulic pump fixedly connected to the coupling. One end of the hydraulic oil outlet of the hydraulic pump is fixedly and sealingly connected to one end of an oil outlet pipe. The oil outlet pipe is provided with a central hole for the oil outlet pipe. The first electrical sealing joint, the first plug, the motor reduction assembly protection cylinder, the oil outlet pipe, the coupling nipple and the support end head form a closed hydraulic oil tank. The hydraulic pump is fixed on the motor reduction assembly fixing frame. A three-position four-way directional control valve is sealingly arranged in a hydraulic reversing through hole of the support end head. An overflow valve is fixedly and sealingly connected in an overflow hole of the support end head. A check valve is fixedly and sealingly connected to the support end head. The hydraulic oil outlet of the hydraulic pump is communicated with a third communication hole of the three-position four-way directional control valve. The check valve is arranged between the hydraulic oil outlet of the hydraulic pump and the third communication hole. The low-pressure oil chamber is communicated with a fourth communication hole of the three-position four-way directional control valve. A first communication hole of the three-position four-way directional control valve is communicated with the hydraulic oil tank. One end of the overflow valve is connected between the first communication hole and the hydraulic oil tank. The other end of the overflow valve is connected between the inlet of the check valve and the hydraulic oil outlet of the hydraulic pump. A second communication hole of the three-position four-way directional control valve is communicated with the high-pressure oil chamber.

[0019] Furthermore, the support end is fixedly and hermetically connected with a high-pressure pressure sensor for detecting the pressure of the high-pressure oil chamber; the support end is fixedly and hermetically connected with a low-pressure pressure sensor for measuring the liquid pressure of the low-pressure oil chamber; the support end is provided with a main high-pressure oil passage and a high-pressure oil through-hole, and the second communication hole of the three-position four-way directional control valve is communicated with the high-pressure oil chamber through the main high-pressure oil passage and the high-pressure oil through-hole.

[0020] Furthermore, it further includes a control circuit: the control circuit includes a motor drive circuit protection cylinder, one end of the motor drive circuit protection cylinder is fixedly and hermetically connected with a second power sealing joint, the other end of the motor drive circuit protection cylinder is fixedly and hermetically connected with a second plug, the second plug is fixedly and hermetically connected with a third power sealing joint, the motor drive circuit protection cylinder is fixedly connected with the circuit board protection chamber, a circuit support plate is fixedly connected inside the motor drive circuit protection cylinder, a motor drive circuit is fixedly connected to the circuit support plate, and the second power sealing joint, the third power sealing joint and the motor drive circuit are electrically connected;

[0021] A power supply battery, a wireless communication circuit and an intelligent control circuit are fixedly connected to the circuit board protection chamber, and the low-pressure pressure sensor, the high-pressure pressure sensor, the three-position four-way directional control valve motor drive circuit and the power supply battery are all connected to the intelligent control circuit.

[0022] Furthermore, a transmission shaft is fixedly connected to the lower end of the inner shaft for connecting with the MWD measurement sub, a lower housing is fixedly connected to the lower end of the housing, an upper moving coil housing, an upper moving ring alloy sleeve, a second thrust bearing group, a half ring, a lower static alloy, a lower moving alloy, a spacer ring, a pressure-bearing ring, an upper static coil housing, an upper static coil alloy sleeve and a lower moving housing are sleeved on the transmission shaft, and the upper moving coil housing and the lower moving housing are fixedly connected to the transmission shaft, the upper moving ring alloy sleeve is fixed on the upper moving coil housing, the upper static coil alloy sleeve is sleeved outside the upper moving ring alloy sleeve and a dynamic friction pair structure is formed between them, the upper static coil alloy sleeve is fixedly connected with the upper static coil housing, the lower moving alloy is fixed on the lower moving housing, the lower static alloy is fixed on the lower static housing, the lower static housing is fixedly connected with the lower housing, and a dynamic friction pair structure is formed between the lower moving alloy and the lower static alloy;

[0023] Wherein, a second thrust bearing group is arranged between the transmission shaft and the lower housing, the inner ring of the second thrust bearing group is limited by the pressure-bearing ring and the upper moving coil housing, and the outer ring of the second thrust bearing group is limited by the spacer ring and the upper static coil housing.

[0024] As can be seen from the above technical solutions, a control tool for a positive displacement motor provided by the present invention has the following beneficial effects:

[0025] The embodiments of the present invention can adjust the magnitude of the frictional torque to balance the reaction torque of the outer shell of the positive displacement motor; it can enable the upper drill string and the lower positive displacement motor to rotate throughout the process to eliminate situations such as drag, thereby achieving the purpose of reducing friction and resistance and increasing the drilling speed; when the positive displacement motor is drilling in a directional sliding mode, it can control the magnitude of the frictional torque to balance the reaction torque of the outer shell of the positive displacement motor, and then effectively control the rotation angle of the tool face of the positive displacement motor to achieve controllability of the wellbore trajectory; moreover, the upper drill string can rotate forward to smoothly transmit the drilling pressure, effectively solving problems such as drag and low mechanical drilling speed generated during the sliding drilling of conventional positive displacement motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the front view of a control tool for a positive displacement motor according to an embodiment of the present invention;

[0027] Figure 2 is the left view of a control tool for a positive displacement motor according to an embodiment of the present invention;

[0028] Figure 3 is Figure 2 the sectional view taken along the line A-A of

[0029] Figure 4 is Figure 3 the partial enlarged view at M in

[0030] Figure 5 is Figure 2 the upper part of the sectional view taken along the line B-B of

[0031] Figure 6 is Figure 2 the upper part of the sectional view taken along the line C-C of

[0032] Figure 7 is Figure 2 the middle part of the sectional view taken along the line D-D of

[0033] [[ID=۴۴]] Figure 8 is Figure 1 the sectional view taken along the line E-E of

[0034] Figure 9 is Figure 1 the sectional view taken along the line F-F of

[0035] Figure 10 is Figure 1 the sectional view taken along the line G-G of

[0036] Figure 11 is Figure 1 the sectional view taken along the line H-H of

[0037] Figure 12 is Figure 1 the sectional view taken along the line I-I of

[0038] Figure 13 It is a schematic diagram of the hydraulic control unit part. Specific implementation manner

[0039] To better understand the purpose, structure and function of the present invention, the following further describes in detail a control tool for a positive displacement motor in conjunction with the accompanying drawings.

[0040] As Figure 1 , Figure 2 shown, it shows a control tool for a positive displacement motor according to an embodiment of the present invention, including an inner shaft 48 and a housing. The upper end of the housing is used to connect with the upper drill string. A transmission control part is arranged between the inner shaft 48 and the housing. The transmission control part is used to balance the reaction torque acting on the outer shell of the positive displacement motor, so that the upper drill string can rotate normally to smoothly transmit the drilling pressure; the lower end of the inner shaft is used to connect with the MWD measurement sub.

[0041] The housing of this embodiment includes a protective shell 3, a connecting sub 5 and an upper housing 7: Among them, the connecting sub 5 is connected to the upper housing 7 through tapered pipe threads, and a static seal is formed between the two through two O-ring seals. The connecting sub 5 and the upper housing 7 are also connected through four first locking pins 6 to prevent the upper housing 7 from loosening; the protective shell 3 is connected to the connecting sub 5 through flat threads, and a static seal is formed between the two through two O-ring seals. The protective shell 3 and the connecting sub 5 are also connected through four second locking pins 4 to prevent the protective shell 3 from loosening.

[0042] Regarding the transmission control part: As Figure 3 , Figure 4 shown, it includes a buffer spring 34 sleeved on the inner shaft 48 and limited on the inner shaft 48; specifically, the lower end of the buffer spring 34 is limited by a shoulder provided on the inner shaft 48, and the upper end of the buffer spring after pre-compression is limited by a first elastic retaining ring 33 fixed on the inner shaft 48; during specific installation, after the buffer spring 34 is pre-compressed, it is sleeved on the inner shaft 48 together with the retaining ring 50, and the first elastic retaining ring 33 is stuck in a groove on the inner shaft 48 to limit the buffer spring 34 and the retaining ring 50.

[0043] A friction assembly is limited between the inner shaft 48 above the buffer spring 34 and the housing. A rotating cavity 016 is arranged above the friction assembly. A moving spline sleeve is sleeved on the inner shaft 48 above the rotating cavity 016. The moving spline sleeve can transmit the torque of the housing to the inner shaft 48, and when the moving spline sleeve 31 moves to the rotating cavity 016, the moving spline sleeve 31 cannot transmit the torque of the housing to the inner shaft 48.

[0044] During specific implementation, eight key grooves are machined on the inner side of the moving spline sleeve 31 to cooperate with the eight long keys on the outer side of the inner shaft 48. Ten long keys are machined on the outer side of the moving spline sleeve 31 to cooperate with the ten key grooves on the inner side of the connecting short section 5. The moving spline sleeve 31 is sleeved on the inner shaft 48. The eight key grooves on the inner side of the moving spline sleeve 31 can freely axially move along the eight long keys on the outer side of the inner shaft 48, and the ten long keys on the outer side of the moving spline sleeve 31 can freely axially move along the ten key grooves on the inner side of the connecting short section 5. Therefore, the moving spline sleeve 31 can move relative to the inner shaft and the housing along the axis direction of the inner shaft 48. When the connecting short section 5 rotates again, the moving spline sleeve 31 can transmit the torque of the connecting short section 5 to the inner shaft 48 to drive the inner shaft 48 to rotate together. And when the moving spline sleeve 31 moves to the rotating cavity 016, since there are no long keys at the rotating cavity, the moving spline sleeve 31 cannot transmit the torque of the housing to the inner shaft 48.

[0045] A support end 25 is fixedly and sealingly connected to the upper end of the inner shaft 48. The lower end of the inner shaft 48 is sealingly connected to the housing. A hydraulic piston is arranged in the sealed hydraulic cavity formed by the inner shaft 48, the support end 25 and the housing. The upper end of the moving spline sleeve 31 is fixedly connected to the hydraulic piston 27. A first return spring 30 is arranged between the moving spline sleeve 31 and the hydraulic piston 27. The lower end of the first return spring 30 is limited by the shoulder of the housing.

[0046] For the hydraulic piston 27, the hydraulic piston 27 is sleeved on the inner shaft 48, and the hydraulic piston 27 can freely axially move along the optical axis surface of the inner shaft 48. The moving spline sleeve 31 is connected to the hydraulic piston 27 through a flat thread. The first return spring 30 is installed between the moving spline sleeve 31 and the hydraulic piston 27. The moving spline sleeve 31 and the hydraulic piston 27 are also connected by four fourth locking pins 29 to prevent the hydraulic piston 27 from loosening. Two first Chebyshev piston rod seals 28 are installed in the inner groove of the hydraulic piston 27 to form a dynamic seal between the hydraulic piston 27 and the inner shaft 48. Two second Chebyshev piston seals 26 are installed in the outer groove of the hydraulic piston 27 to form a dynamic seal between the hydraulic piston 27 and the support end 25. The inner shaft 48 and the support end 25 are fixedly connected by a flat thread. Two O-ring seals are arranged before and after the flat thread position to form a static seal between the inner shaft 48 and the support end 25. The hydraulic piston 27 can freely axially move in the hydraulic cylinder structure formed by the inner shaft 48 and the support end 25.

[0047] The support end 25 is fixedly and sealingly connected to an external structure. A circuit board protection chamber 21 is fixedly and sealingly arranged between the support end 25 and the external structure. A drive assembly is fixedly arranged on the support end 25. The drive assembly is located in the inner cavity formed by the support end 25, the external structure and the circuit board protection chamber 21. The drive assembly is connected to the hydraulic control unit. The hydraulic control unit is used to supply high-pressure oil to the high-pressure oil chamber 059 above the hydraulic piston 27.

[0048] The friction assembly of this embodiment is used to generate friction torque under the action of the hydraulic piston 27.

[0049] Specifically, the friction assembly includes a plurality of movable friction plates 52, which are all arranged above the buffer spring 34, and are connected to the inner shaft 48 through keys. A stator friction plate 32 is arranged between two adjacent movable friction plates 52, and the stator friction plates 32 are connected to the shell through keys. The lowest movable friction plate 52 is limited by a support ring 51 between it and the buffer spring 34, and the support ring 51 can compress the buffer spring 34 and move downward after being subjected to force, and the highest movable friction plate 52 is limited by a second elastic retaining ring 53 fixed on the inner shaft.

[0050] Regarding the friction assembly: eight long keys are processed on the outside of the inner shaft 48, and eight key slots are processed on the inside of each movable friction plate 52. The key slots of the movable friction plate 52 cooperate with the long keys on the inner shaft 48, so that the inner shaft 48 and the movable friction plate 52 rotate together; ten long keys are processed on the outside of the stator friction plate 32, and ten key slots are processed on the inside of the connecting short section 5. The long keys of the stator friction plate 32 cooperate with the key slots on the connecting short section 5, so that the stator friction plate 32 and the connecting short section 5 rotate together; three stator friction plates 32 and four movable friction plates 52 are arranged alternately and are passed on the inner shaft 48 together with the support ring 51. The second elastic retaining ring 53 is clamped in the clamping groove on the inner shaft 48 to position the uppermost movable friction plate 52.

[0051] The rotating cavity 016 is arranged above the uppermost rotor friction plate 52. In a specific implementation, the rotating cavity 016 can be formed by removing the aforementioned keyway in the middle position of the connecting short section 5.

[0052] The control tool for the screw drill according to the embodiment of the present invention is explained again as follows: the drive assembly is used to drive the hydraulic control unit, and the hydraulic control unit is used to pump high-pressure oil into the high-pressure oil chamber. The high-pressure oil causes the hydraulic piston 27 to move toward the low-pressure oil chamber. After the hydraulic piston 27 moves to the rotating chamber, it continues to move downward, causing the friction assembly to generate a friction torque. The friction torque at this location causes the inner shaft 48 to be in a critical equilibrium state where it stops rotating, thereby keeping the tool face stationary, or the friction torque causes the inner shaft 48 to rotate clockwise or counterclockwise, thereby achieving adjustment of the tool face.

[0053] The embodiments of the present invention can adjust the magnitude of the frictional torque to balance the reaction torque of the outer shell of the positive displacement motor; enable the upper drill string and the lower positive displacement motor to rotate throughout to eliminate situations such as drag, and achieve the purpose of reducing friction and resistance and increasing the drilling speed; when the positive displacement motor is drilling with directional sliding, it can control the magnitude of the frictional torque to balance the reaction torque of the outer shell of the positive displacement motor, and then effectively control the rotation angle of the tool face of the positive displacement motor to realize the controllability of the wellbore trajectory; and the upper drill string can rotate forward smoothly to transmit the drilling pressure, effectively solving problems such as drag and low mechanical drilling speed generated during the sliding drilling of conventional positive displacement motors.

[0054] When compound drilling, lock the outer shell of the positive displacement motor and the upper drill string together for normal compound drilling.

[0055] In one embodiment, as Figure 5 shown, a locking piston 74 is hermetically arranged in the sealed hydraulic cavity. The locking piston 74 is located between the support end 25 and the hydraulic piston 27. A high-pressure oil cavity 059 is formed between the locking piston 74 and the hydraulic piston 27. The cavities on the side of the locking piston 74 away from the hydraulic piston 27 and the cavities on the side of the hydraulic piston away from the locking piston 74 are both low-pressure oil cavities 041; a second return spring 71 is arranged between the locking piston 74 and the support end 25. A locking block 75 is arranged in the radial movement hole of the hydraulic piston 27. When the hydraulic piston 27 moves axially, the locking block 75 moves radially along the chute slope on the outer side surface of the inner shaft 48. And after the locking piston 74 moves to the unlocking position in the direction of the low-pressure oil cavity 041 away from the hydraulic piston 27, the locking piston 74 is disengaged from the locking block 75.

[0056] The locking piston 74 and the second return spring 71 are inserted into the piston locking hole of the support end 25. The locking piston 74 can move axially freely. The stop ring 73 is installed in the piston locking hole of the support end 25 through a flat thread. The locking block 75 is inserted into the radial movement hole of the hydraulic piston 27. When the hydraulic piston 27 moves axially, the locking block 75 can move radially along the chute slope on the outer side surface of the inner shaft 48. After the locking piston 74 moves to the unlocking position, the baffle of the locking piston 74 is disengaged from the locking block 75, and the locking piston 74 is disengaged from the locking block 75.

[0057] Among them, the external structure includes a protection cylinder 20 arranged on the outer side of the support end 25. The support end 25 is fixedly and hermetically connected to the protection cylinder 20. The protection cylinder 20 is fixedly and hermetically connected to the upper end head 15 of the protection chamber. The circuit board protection chamber 21 is arranged in the inner cavity formed by the support end 25 and the upper end head 15 of the protection chamber. The circuit board protection chamber 21 is in key connection with both the support end 25 and the upper end head 15 of the protection chamber, and is hermetically arranged between the circuit board protection chamber 21 and the support end 25 and the upper end head 15 of the protection chamber.

[0058] Specifically, the support end 25 is connected to the protection cylinder 20 by a flat thread, and a static seal is formed between the two by two O-ring seals; the other end of the protection cylinder 20 is connected to the upper end head 15 of the protection chamber by a flat thread, and a static seal is formed between the two by two O-ring seals; the support end 25 and the protection cylinder 20, and the protection cylinder 20 and the upper end head 15 of the protection chamber are respectively connected by four locking pins 57 to prevent the protection cylinder 20 from loosening; both ends of the circuit board protection chamber 21 are inserted into the inner cavities of the upper end head 15 of the protection chamber and the support end 25, and the keys at both ends of the circuit board protection chamber 21 are respectively inserted into the key grooves in the inner cavities of the upper end head 15 of the protection chamber and the support end 25 to transmit torque, and static seals are formed between the circuit board protection chamber 21 and the upper end head 15 of the protection chamber, and between the circuit board protection chamber 21 and the support end 25 by two O-ring seals respectively.

[0059] As Figure 5 shown, a pressure sensor 83 is fixedly and sealingly connected to the upper end head 15 of the protection chamber. A mud pressure tapping cavity 046, a mud channel 047, and a mud pressure tapping hole 048 that are sequentially communicated are formed on the upper end head 15 of the protection chamber. The pressure sensor 83 extends into the mud pressure tapping hole 048. The pressure sensor 83 is used to measure the mud pressure in the central flow channel of the upper end head 15 of the protection chamber. A mud sieve plate 86 is fixed at the mud pressure tapping cavity 046 by an elastic retaining ring 84.

[0060] Specifically, the pressure sensor 83 is installed on the upper end head 15 of the protection chamber by a flat thread, and a static seal is formed between the two by two O-ring seals; a mud pressure tapping cavity 046, a mud channel 047, and a mud pressure tapping hole 048 that are sequentially communicated are formed on the upper end head 15 of the protection chamber. The mud pressure tapping hole 048 is a through hole axially penetrating the upper end head 15 of the protection chamber. The end of the mud pressure tapping hole 048 away from the central flow channel is sealed by a sealing plug 85; the sealing plug 85 is installed on the upper end head 15 of the protection chamber by a flat thread, and a static seal is formed between the two by an O-ring seal; the elastic retaining ring 84 fixes the mud sieve plate 86 on the upper end head 15 of the protection chamber. The mud sieve plate 86 is used to ensure that only mud enters the mud pressure tapping cavity 046 to prevent it from being blocked. The pressure sensor 83 is used to measure the pressure of the mud passing through the central channel of the upper end head 15 of the protection chamber through the mud pressure tapping cavity 046, the mud channel 047, and the mud pressure tapping hole 048.

[0061] Among them, a first thrust bearing group 14 is sleeved on the upper end head 15 of the protection bin. The lower end of the inner ring of the first thrust bearing group 14 is limited by a shoulder provided on the upper end head 15 of the protection bin. A first fixing ring 13 is threadedly connected to the upper end head 15 of the protection bin. The first fixing ring 13 is used to limit the upper end of the inner ring of the first thrust bearing group 14. The upper end of the housing is threadedly connected with an upper joint 1. The housing and the upper joint 1 are fixedly connected. The upper joint 1 is used to connect with the upper drill string. The upper joint 1 is used to limit the upper end of the outer ring of the first thrust bearing group 14. The lower end of the outer ring of the first thrust bearing group 14 is limited by a step provided on the housing.

[0062] Regarding the upper joint 1: The upper joint 1 is connected to the protection shell 3 through a flat thread, and the two form a static seal through two O-ring seals. Four sixth locking pins 2 are also connected between the two to prevent the upper joint 1 from loosening. The upper joint 1 is connected to the upper drill string through a tapered pipe thread.

[0063] A second fixing ring 16 is also provided between the upper end head 15 of the protection bin and the protection shell 3. The second fixing ring 16 is used to limit the first Chebyshev sealing spacer ring 17, O-ring seal 18, and first Chebyshev rotary seal ring 19 below it.

[0064] The first thrust bearing group 14 is sleeved on the upper end head 15 of the protection bin. The first fixing ring 13 is connected to the upper end head 15 of the protection bin through a flat thread to fix the upper end of the inner ring of the first thrust bearing group 14 through the first fixing ring 13. The first fixing ring 13 and the upper end head 15 of the protection bin are fixed through four fifth locking pins 12 to prevent the first fixing ring 13 from loosening; the upper joint 1 is used to limit the upper end of the outer ring of the first thrust bearing group 14. The lower end of the outer ring of the first thrust bearing group 14 is limited by a step on the protection shell 3. The lower end of the inner ring of the first thrust bearing group 14 is limited by a shoulder on the upper end head 15 of the protection bin. The first thrust bearing group 14 in this embodiment can offset the axial and radial vibrations transmitted by the upper end head 15 of the protection bin.

[0065] Among them, as Figure 5 shown, the drive assembly includes a motor reduction assembly 62. The motor reduction assembly 62 is fixed on a motor reduction assembly fixing bracket 65. The output shaft of the motor reduction assembly 62 is connected to the hydraulic control unit through a coupling 64. The cable of the motor reduction assembly 62 is connected to the corresponding joint of the first electrical sealing joint 59. The first electrical sealing joint 59 is fixedly and sealingly connected to the first plug 60. The first plug 60 is fixedly and sealingly connected to the motor reduction assembly protection cylinder 63. The motor reduction assembly protection cylinder 63 is fixedly and sealingly connected to one end of a pair of screws 68. The other end of the pair of screws 68 is fixedly and sealingly connected to the support end head 25.

[0066] Specifically, the motor reduction assembly 62 is fixed to the motor reduction assembly fixing bracket 65 by four screws. The first plug 60 is connected to the motor reduction assembly protection cylinder 63 through a flat thread, and the two are statically sealed by two O-ring seals. The first plug 60 axially fixes the motor reduction assembly 62 through the support pipe 61 to prevent the axial movement of the motor reduction assembly 62. The first electrical sealing joint 59 is connected to the first plug 60 through a flat thread, and the two are statically sealed by two O-ring seals. The inner eight pins of the first electrical sealing joint 59 are connected to the eight flexible cables of the motor reduction assembly 62. The output shaft of the motor reduction assembly 62 is connected to the hydraulic pump 66 of the hydraulic control unit through a coupling 64. The motor reduction assembly 62 and the coupling 64 are locked by a locking pin. The other end of the motor reduction assembly fixing bracket 65 is connected to the hydraulic pump 66 through a flat thread.

[0067] Among them, as Figure 13 shown, the hydraulic control unit includes a hydraulic pump 66 fixedly connected to the coupling 64. The hydraulic oil outlet of the hydraulic pump 66 is fixedly and sealedly connected to one end of the oil outlet pipe 67. The oil outlet pipe 67 is provided with an oil outlet pipe central hole 037. The first electrical sealing joint 59, the plug 60, the motor reduction assembly protection cylinder 63, the oil outlet pipe 67, the coupling nut 68 and the support end 25 form a closed hydraulic oil tank. The hydraulic pump 66 is fixed on the motor reduction assembly fixing bracket 65. A three-position four-way directional control valve 22 is hermetically arranged in the hydraulic reversing through hole of the support end 25. An overflow valve 96 is fixedly and sealedly connected in the overflow hole of the support end 25. A check valve 69 is fixedly and sealedly connected to the support end 25. The hydraulic oil outlet of the hydraulic pump 66 is communicated with the No. 3 communication hole 08 of the three-position four-way directional control valve 22. The check valve is arranged between the hydraulic oil outlet of the hydraulic pump 66 and the No. 3 communication hole 08. The low-pressure oil cavity 041 is communicated with the No. 4 communication hole 05 of the three-position four-way directional control valve 22. The No. 1 communication hole 011 of the three-position four-way directional control valve 22 is communicated with the hydraulic oil tank. One end of the overflow valve is connected between the No. 1 communication hole 011 and the hydraulic oil tank, and the other end of the overflow valve is connected between the inlet of the check valve 69 and the hydraulic oil outlet of the hydraulic pump 66. The No. 2 communication hole 09 of the three-position four-way directional control valve 22 is communicated with the high-pressure oil cavity 059.

[0068] Specifically, for the hydraulic pump and the coupling, the input end one-way key of the hydraulic pump 66 is inserted into the one-way key groove at the other end of the coupling 64. The connection of the hydraulic pump 66, the coupling 64 and the motor reduction assembly 62 enables the motor reduction assembly 62 to drive the hydraulic pump 66 to work properly.

[0069] As Figure 10 shown, the support end 25 is provided with a high-pressure oil main channel 051 and a high-pressure oil through hole 052. The No. 2 communication hole 09 of the three-position four-way directional control valve 22 is communicated with the high-pressure oil cavity 059 through the high-pressure oil main channel 051 and the high-pressure oil through hole 052.

[0070] The hydraulic oil outlet of the hydraulic pump 66 is connected to the oil outlet pipe 67 by a flat thread, and a static seal is formed between the two through an O-ring seal combination; the other end of the motor reduction assembly protection cylinder 63 is connected to the nipple 68 by a flat thread, and a static seal is formed between the two through two O-ring seals; the other end of the nipple 68 is installed on the support end 25 by a flat thread, and a static seal is formed between the two through two O-ring seals; the oil outlet pipe 67 is installed on the oil outlet of the support end 25 by a flat thread, and a static seal is formed between the two through two O-ring seals; the first electric seal joint 59, the first plug 60, the motor reduction assembly protection cylinder 63, the oil outlet pipe 67, the nipple 68 and the support end 25 form a micro hydraulic oil tank and are filled with hydraulic oil; the check valve 69 is installed on the support end 25 by a flat thread, and a static seal is formed between the two through an O-ring seal; the plug 70 is installed in the main oil supply passage of the support end 25 by a flat thread, and a static seal is formed between the plug 70 and the main oil supply passage of the support end 25 through two O-ring seals.

[0071] For the sealed hydraulic chamber, the chamber between the hydraulic piston 27 and the locking piston 74 is the high-pressure oil chamber 059 of the sealed hydraulic chamber. When injecting oil into the high-pressure chamber, hydraulic oil is injected into the high-pressure oil chamber 059 through the first oil injection hole 042 of the support end 25. The first NPT seal plug 76 is used to seal the first oil injection hole 042. During the oil injection process through the first oil injection hole 042, the high-pressure oil main passage 051 and the high-pressure oil through hole 052 are vent holes.

[0072] For the low-pressure oil chamber 041 of the sealed hydraulic chamber, the inner cavity 18 of the moving spline sleeve, the rotating chamber 016 and other low-pressure oil chambers 041 are filled with hydraulic oil through the second oil injection hole 030 on the upper end head 15 of the protection chamber, the transition oil chamber 031, and the oil passing groove 029 on the outside of the protection cylinder. During the oil injection process, exhaust is carried out through the exhaust hole 049 of the upper end head 15 of the protection chamber, and sealing is carried out respectively through the second NPT seal plug 58 and the third NPT seal plug 87.

[0073] Among them, the overflow valve 96 is installed on the support end 25 by a flat thread, and a static seal is formed between the two through an O-ring seal; the overflow valve 96 is inserted into the overflow hole of the support end 25, and a static seal is formed between the two through an O-ring seal group.

[0074] The three-position four-way directional valve is an electromagnetic three-position four-way threaded cartridge valve. The three-position four-way directional valve 22 is inserted into the hydraulic direction-changing through hole of the support end 25, and the two are connected by a flat thread and a static seal is formed through an O-ring seal; as Figure 12As shown, a first support end-connector communication hole 04 is provided on the support end. The two sides of the first support end-connector communication hole 04 on the support end and the second support end-connector communication hole 07 form a static seal with the protection cylinder 20 through two O-ring seals. The two sides of the four hydraulic channels of the three-position four-way directional control valve 22, namely the fourth communication hole 05, the third communication hole 08, the second communication hole 09, and the first communication hole 011, form a static seal with the support end 25 through O-ring seal groups respectively.

[0075] Regarding the flow of hydraulic oil: The hydraulic pump 66 starts under the drive of the motor reduction assembly 62. After starting, the hydraulic pump 66 sucks in hydraulic oil from its oil suction port 033. The sucked hydraulic oil is pumped out from its oil outlet 034 after being boosted by the hydraulic pump 66. The high-pressure hydraulic oil opens the one-way valve 69 through the central hole 037 of the oil outlet pipe and enters the main oil supply through-hole 039. Then it passes through the annular hydraulic channel 043, the second support end-connector communication hole 07, the third communication hole 08, the second communication hole 09 and enters the main high-pressure oil channel 051. Finally, the high-pressure hydraulic oil enters the high-pressure oil cavity 059 through the high-pressure oil through-hole 052. The hydraulic oil returning in the low-pressure oil cavities 041 such as the return spring cavity 013, the rotation cavity 016, and the inner cavity of the moving spline sleeve 018 enters from the second row of hydraulic radial communication holes 017 of the inner shaft, and successively passes through the inner shaft hydraulic through-hole 019, the first row of hydraulic radial communication holes 020 of the inner shaft, the support end hydraulic radial communication hole 021, the support end hydraulic through-hole 024, the adapter center hole 025, the adapter radial hole 027, the support end communication hole 026, the first support end-connector communication hole 04 and then enters the fourth communication hole 05. Then it successively passes through the main return oil radial through-hole 012, the main return oil through-hole 057, the return oil radial through-hole 058, the return oil channel 036 and the return oil transition cavity 035 and then enters the oil storage cavity 032; one end of the inner shaft hydraulic through-hole 019 is provided with an NPT seal plug 47, and the upper end of the main return oil through-hole 057 is provided with a seal, as Figure 11 As shown, the main return oil through-hole 057 and the return oil radial through-hole 058 are provided on the support end 25.

[0076] Among them, a high-pressure pressure sensor 93 is fixedly and sealedly connected to the support end 25. The high-pressure pressure sensor 93 is used to detect the pressure in the high-pressure oil cavity 059; a low-pressure pressure sensor 56 is fixedly and sealedly connected to the support end 25. The low-pressure pressure sensor 56 is used to measure the liquid pressure in the low-pressure oil cavity 041.

[0077] Specifically, the high-pressure pressure sensor 93 is connected to the first adapter 94 through a flat thread, and the two form a static seal through two O-ring seals; the first adapter 94 is installed on the support end 25 through a flat thread, and the two form a static seal through two O-ring seals. The low-pressure pressure sensor 56 is connected to the second adapter 55 through a flat thread, and the two form a static seal through two O-ring seals; the second adapter 55 is installed on the support end 25 through a flat thread, and the two form a static seal through two O-ring seals.

[0078] Among them, the control tool for the positive displacement motor of the present invention further includes a control circuit, and the control circuit is used to control the drive assembly and the like.

[0079] Specifically, the control circuit includes a motor drive circuit protection cylinder 79. One end of the motor drive circuit protection cylinder 79 is fixedly and sealingly connected to a second electrical seal joint 77. The other end of the motor drive circuit protection cylinder 79 is fixedly and sealingly connected to a second plug 78. The second plug 78 is fixedly and sealingly connected to a second electrical seal joint 82. The motor drive circuit protection cylinder 79 is fixedly connected to the circuit board protection chamber 21. A circuit support plate 81 is fixedly connected inside the motor drive circuit protection cylinder 79. A motor drive circuit 80 is fixedly connected to the circuit support plate 81. The second electrical seal joint 77 and the third electrical seal joint 82 are electrically connected to the motor drive circuit 80.

[0080] The second electrical seal joint 77 is installed on the second plug 78 through a flat thread, and the two form a static seal through two O-ring seals; the second plug 78 is connected to the motor drive circuit protection cylinder 79 through a flat thread, and the two form a static seal through two O-ring seals; the motor drive circuit 80 is fixed to the circuit support plate 81 by four fixing screws; the circuit support plate 81 is connected to the motor drive circuit protection cylinder 79 through a flat thread, and the two form a static seal through two O-ring seals; the third electrical seal joint 82 is installed on the circuit support plate 81 through a flat thread, and the two form a static seal through two O-ring seals; the inner needles of the third electrical seal joint 82 and the second electrical seal joint 77 are both connected to the motor drive circuit 80 through a flexible cable. The motor drive circuit 80 is located in the drive circuit protection chamber 045; the motor drive circuit protection cylinder 79 is filled with encapsulating glue. The motor drive circuit protection cylinder 79 is fixed to the circuit board protection chamber 21 by eight fixing screws. The first electrical seal joint 59 and the second electrical seal joint 77 are connected by a flexible cable.

[0081] A power supply battery 91, a wireless communication circuit 97 and an intelligent control circuit 98 are fixedly connected to the circuit board protection chamber 21. The low-pressure pressure sensor 56, the high-pressure pressure sensor 93, the three-position four-way directional control valve 22 and the motor drive circuit 80 are all connected to the intelligent control circuit 98.

[0082] Specifically, as Figure 6 shown, two fourth power seal joints 89 are installed on the circuit board protection bin 21 through flat threads, and static seals are respectively formed between the two fourth power seal joints 89 and the circuit board protection bin 21 through two O-ring seals; an installation hole for placing the intelligent control circuit 98 is provided on the circuit board protection bin 21, and a cover plate 98 is connected at this installation hole; the power supply battery 91 is fixed on the circuit board protection bin 21 through four fixing screws and filled with encapsulating glue, and the inner five needles of the two fourth power seal joints 89 are connected to the power supply battery 91 through a flexible cable; the first cover plate 92 is fixed on the circuit board protection bin 21 through a plurality of fixing screws, and a static seal is formed between the two through an O-ring seal; four fifth power seal joints 100 are installed on the circuit board protection bin 21 through flat threads, and static seals are respectively formed between them and the circuit board protection bin 21 through two O-ring seals; the wireless communication circuit 97 and the intelligent control circuit 98 are connected through a flexible cable, and the wireless communication circuit 97 and the intelligent control circuit 98 are fixed on the circuit board protection bin 21 through fixing screws; the inner five needles of the four fifth power seal joints 100 are respectively connected to the intelligent control circuit 98 through a flexible cable and filled with encapsulating glue; the second cover plate 98 is fixed on the circuit board protection bin 21 through a plurality of fixing screws, and a static seal is formed between the two through an O-ring seal. The low-pressure pressure sensor 56, the pressure sensor 83, the high-pressure pressure sensor 93, the three-position four-way directional control valve 22, and the motor drive circuit 80 are all connected to the intelligent control circuit 98 through a flexible cable with the power supply battery 91. An oil injection hole 050 for injecting oil into the annulus 02 of the circuit board bin is provided on the upper end head 15 of the protection bin, and this oil injection hole 050 is sealed by a sealing plug. The annulus 02 of the circuit board bin is filled with anti-seismic oil, which can not only buffer vibrations but also transfer the heat generated by electronic components.

[0083] When the embodiment of the present invention is used for the control tool of the positive displacement motor to detect the working condition at the wellhead, the tool detection signal can be transmitted in real time through the wireless communication circuit 97, that is, the wireless communication circuit 97 is used for the communication between the wellhead and the intelligent control circuit 98, the intelligent control circuit 98 is used to control the three-position four-way directional control valve 22 and the motor drive circuit 80, and the intelligent control circuit 98 is also used to adjust the output pump pressure of the hydraulic pump.

[0084] Further, a transmission shaft 11 is fixedly connected to the lower end of the inner shaft. The transmission shaft is used to connect with the MWD measurement sub. A lower housing 8 is fixedly connected to the lower end of the housing. An upper moving coil housing 37, an upper moving ring alloy sleeve 38, a second thrust bearing group 39, a half ring 40, a lower static alloy 41, a lower moving alloy 42, a spacer ring 43, a pressure-bearing ring 44, an upper static coil housing 45, an upper static coil alloy sleeve 46 and a lower moving housing 10 are sleeved on the transmission shaft 11. The upper moving coil housing 37 and the lower moving housing 10 are fixedly connected to the transmission shaft 11. The upper moving ring alloy sleeve 38 is fixed on the upper moving coil housing 37. The upper static coil alloy sleeve 46 is sleeved outside the upper moving ring alloy sleeve 38 and a dynamic friction pair structure is formed between them. The upper static coil alloy sleeve 46 is fixedly connected to the upper static coil housing 45. The lower moving alloy 42 is fixed on the lower moving housing 10. The lower static alloy 41 is fixed on the lower static housing 9. The lower static housing 9 is fixedly connected to the lower housing 8. A dynamic friction pair structure is formed between the lower moving alloy 42 and the lower static alloy 41.

[0085] A second thrust bearing group 39 is arranged between the transmission shaft 11 and the lower housing 8. The inner ring of the second thrust bearing group 39 is limited by the pressure-bearing ring 44 and the upper moving coil housing 37. The outer ring of the second thrust bearing group 39 is limited by the spacer ring 43 and the upper static coil housing 45.

[0086] Specifically, the upper moving coil housing 37, the upper moving ring alloy sleeve 38, the second thrust bearing group 39, the half ring 40, the lower static alloy 41, the lower moving alloy 42, the spacer ring 43, the pressure-bearing ring 44, the upper static coil housing 45 and the upper static coil alloy sleeve 46 are sleeved on the transmission shaft 11; the lower moving housing 10 is fixed on the transmission shaft 11 through a flat thread. The upper moving coil housing 37 is fixed on the transmission shaft 11 through a flat thread. The upper moving ring alloy sleeve 38 is installed on the upper moving coil housing 37. The upper static coil alloy sleeve 46 is sleeved on the outer layer of the upper moving ring alloy sleeve 38. The upper moving ring alloy sleeve 38 and the upper static coil alloy sleeve 46 form a dynamic friction pair structure; the lower moving alloy 42 is installed on the lower moving housing 10. The lower static alloy 41 is installed on the lower static housing 9. The lower static alloy 41 and the lower moving alloy 42 form a dynamic friction pair structure; the lower static housing 9 is fixed on the lower housing 8 through a flat thread. The upper static coil housing 45 is installed at the step surface of the lower housing 8; the second thrust bearing group 39, the half ring 40 and the pressure-bearing ring 44 are fixedly clamped in the middle to effectively offset the axial and radial vibrations of the transmission shaft 11.

[0087] The upper housing 7 is connected to the housing 8 through a tapered pipe thread, and the inner shaft 48 is connected to the transmission shaft 11 through a flat thread. Again, a radial communication hole 01 is provided on the upper housing 7, and the radial communication hole 01 communicates with the central flow channel of the lower housing 8. A sealing structure is provided above the radial communication hole (01), and this sealing structure is used to prevent the mud from flowing upward; for the sealing structure: four second Chebyshev sealing spacer rings 35 and the second Chebyshev rotary sealing ring 36 are sleeved on the inner shaft 48 to form a rotary dynamic seal. The four second Chebyshev sealing spacer rings 35 and the second Chebyshev rotary sealing ring 36 are fixed in the inner cavity of the upper housing 7 through the third fixing ring 49. The four second Chebyshev sealing spacer rings 35 and the inner cavity of the upper housing 7 form a static seal through four O-ring seals. The setting of the radial communication hole 01 enables the mud circulating in the wellbore annulus to flow into the central flow channel of the lower housing 8, thereby lubricating and cooling components such as the upper moving coil housing 37, the upper moving ring alloy sleeve 38, the second thrust bearing group 39, the half ring, the lower static alloy 41, the lower moving alloy 42, the spacer ring 43, the pressure-bearing ring 44, the upper static coil housing 45, the upper static coil alloy sleeve 46 and the inner shaft 48.

[0088] For the control tool for the positive displacement motor according to the embodiment of the present invention: The housing structure composed of components such as the upper sub 1, the protective shell 3, the connecting nipple 5, the upper housing 7, the housing 8, the lower static housing 9, etc. can rotate with the upper drill string; the transmission shaft structure composed of components such as the lower moving housing 10, the transmission shaft 11, the upper end head of the protection chamber 15, the protection cylinder 20, the circuit board protection chamber 21, the support end head 25, the upper moving coil housing 37, the inner shaft 48, etc. can rotate together with the MWD measurement nipple and the housing of the positive displacement motor.

[0089] For the control tool for the positive displacement motor according to the embodiment of the present invention, the introduction of its working principle is as follows:

[0090] (1) Automatic balance anti-torque working principle:

[0091] The upper sub 1 is connected to the upper drill string, the transmission shaft 11 is connected to the MWD measurement nipple, the MWD measurement nipple is connected to the housing of the positive displacement motor, and the anti-torque of the drill bit acts on the housing of the positive displacement motor, and the anti-torque of the drill bit acts on the transmission shaft 11 through the MWD measurement nipple.

[0092] During directional drilling, after the tool face of the positive displacement motor is monitored by the MWD measurement sub to reach the predetermined position I for directional drilling, the wellhead sends the balanced torque pressure pulse command A. After the pressure sensor 83 measures this pressure pulse command, it transmits the command to the intelligent control circuit 98. The intelligent control circuit 98 automatically issues an instruction to the three-position four-way directional control valve 22 for commutation. The three-position four-way directional control valve 22 commutates from the leftmost position I to the middle position II. The intelligent control circuit 98 automatically issues a motor drive instruction to the motor drive circuit 80. The motor drive circuit 80 energizes the motor reduction assembly 62 to rotate. The motor reduction assembly 62 drives the hydraulic pump 66 to work through the coupling 64. The high-pressure hydraulic oil pumped out by the hydraulic pump enters the high-pressure oil chamber 059 (the path of the hydraulic oil entering the high-pressure oil chamber has been described before and will not be elaborated here). The hydraulic oil in the high-pressure oil chamber 059 drives the locking piston 74 to compress the second return spring 71 and move towards the low-pressure oil chamber 041. When the locking piston 74 moves to the unlocking position, the locking piston 74 disengages from the locking block 75. The hydraulic piston 27 continues to compress the return spring 30 under the action of the hydraulic oil in the high-pressure oil chamber 059 and drives the moving spline sleeve 31 to move towards the rotary chamber 016 together.

[0093] When the moving spline sleeve 31 moves along the inner shaft 48 and the connecting sub 5 to the rotary chamber 016, the inner shaft 48 disengages from the torque transmission of the upper drill string with the connecting sub 5. The moving spline sleeve 31 continues to move along the inner shaft 48 against the first rotor friction plate 52. The first rotor friction plate 52 transfers the pressure to the first stator friction plate 32. The first stator friction plate 32 moves along the connecting sub 5 and sequentially transfers the pressure to the mating rotor friction plates 52 and stator friction plates 32. The contact surface between the rotor friction plate 52 and the stator friction plate 32 generates frictional force under the action of the pressure. The rotor friction plate 52 rotates with the inner shaft 48 and the transmission shaft 11. The stator friction plate 32 rotates with the connecting sub 5 and follows the upper drill string. The frictional force on the contact surface between the rotor friction plate 52 and the stator friction plate 32 becomes frictional torque. The rotor friction plate 52 and the stator friction plate 32 move towards the buffer spring 34 under the action of the moving spline sleeve 31. The fourth rotor friction plate 52 moves against the support ring 51. The support ring 51 moves against the retaining ring 50 and compresses the buffer spring 34 at the same time. The intelligent control circuit 98 adjusts the frictional torque acting on the rotor friction plate 52 and the stator friction plate 32 by the hydraulic piston 27 by adjusting the output pump pressure of the hydraulic pump 66. The greater the pressure acting on the rotor friction plate 52 and the stator friction plate 32 by the hydraulic piston 27, the greater the generated frictional torque. The rotor friction plate 52 and the stator friction plate 32 can move to the position of the first snap ring 33. This buffer distance can prevent the sudden increase in the frictional torque of the rotor friction plate 52 and the stator friction plate 32 caused by the sudden increase in the hydraulic pressure of the hydraulic pump 6 June ]

[0094] After that, the mover friction plate 52 and the stator friction plate 32 stop moving, and the frictional torque increases with the increase of the output pressure of the hydraulic pump 66. The spline keyway 015 in the connecting sub and the communicating groove 060 can conduct hydraulic oil. As Figure 8 shown, the communicating groove 060 is arranged on the inner shaft 48. During the process of the hydraulic piston 27 moving towards the rotating cavity 016, the hydraulic oil return in the low-pressure cavities such as the reset spring cavity 013, the rotating cavity 016, and the inner cavity 018 of the moving spline sleeve enters from the second row of hydraulic radial communication holes 017 of the inner shaft, and successively passes through the hydraulic through hole 019 of the inner shaft, the first row of hydraulic radial communication holes 020 of the inner shaft, the hydraulic radial communication hole 021 of the support end, the hydraulic through hole 024 of the support end, the center hole 025 of the adapter, the radial hole 027 of the adapter, the communication hole 026 of the support end, and the communication hole 04 of the support end, and then enters the fourth communication hole 05 of the three-position four-way directional control valve; the low-pressure pressure sensor 56 can measure the hydraulic oil pressure in the low-pressure oil cavity 041. The hydraulic oil return enters the main return radial through hole 012, and then as Figure 7 , Figure 9 shown, it successively passes through the main return hole 057, the return radial through hole 058, the center hole 037 of the outlet pipe, the return oil passage 036, and the return oil transition cavity 035 and enters the oil storage cavity 032. The working principle diagram of the hydraulic control system is as Figure 13 shown.

[0095] The intelligent control circuit 98 can measure the rotation angle of the inner shaft 48 in real time. According to the mechanical transmission structure, the intelligent control circuit 98 can measure the tool face angle of the positive displacement motor in real time. The intelligent control circuit 98 controls the motor reduction assembly 62 to drive the hydraulic pump 66 to continuously increase the pressure on the mover friction plate 52 and the stator friction plate 32 until the frictional torque between the mover friction plate 52 and the stator friction plate 32 makes the inner shaft 48 in a critical equilibrium state of stopping rotation, that is, the equilibrium torque. At this time, for example, the equilibrium hydraulic oil pressure at the outlet of the hydraulic pump 66 is P A , and at this time, the intelligent control circuit 98 monitors that the inner shaft 48 remains stationary, that is, the tool face remains stationary at a°.

[0096] That is to say, the present invention can pump high-pressure oil into the high-pressure oil cavity through the hydraulic pump, so that the frictional torque between the mover friction plate 52 and the stator friction plate 32 converted from the acting force of the hydraulic piston 27 on the mover friction plate 52 and the stator friction plate 32 can balance the aforementioned reaction torque, thereby keeping the tool face stationary.

[0097] (2) Automatic balance working principle of the tool face 0±5°:

[0098] When the tool face angle a° is in the range of 0 to 180° clockwise, the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically reduce the output pump pressure to P B, to reduce the frictional torque between the mover friction plate 52 and the stator friction plate 32, which is less than the balancing torque, causing the inner shaft 48 to rotate counterclockwise until the intelligent control circuit 98 monitors that the tool face rotates to around 0 ± 5°, then the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically increase the output pump pressure to the balancing hydraulic oil pressure P A , when the intelligent control circuit 98 measures that the tool face at 0 ± 5° remains stationary, the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to continuously output the pump pressure P A .

[0099] When the tool face angle a° is in the range of 180 - 360° clockwise, the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically increase the output pump pressure to the hydraulic oil pressure P C , increasing the frictional torque between the mover friction plate 52 and the stator friction plate 32, which is greater than the balancing torque to drive the inner shaft 48 to rotate clockwise until the intelligent control circuit 98 monitors that the tool face rotates to around 0 ± 5°, then the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically reduce the output pump pressure to the balancing hydraulic oil pressure P A And continuously supply pressure.

[0100] (3) Working principle of automatically adjusting the tool face to b°:

[0101] The MWD measurement sub monitors that the tool face angle of the current positive displacement motor is around 0 ± 5° and transmits this monitoring signal to the surface. It is necessary to adjust the tool face angle of the positive displacement motor to b°:

[0102] When the adjusted angle b° is in the range of 0 - 180° clockwise, the wellhead sends an angle adjustment pressure pulse command B, and each command adjusts the positive rotation by X° (X = 5°). After the pressure sensor 83 measures this command, it transmits this command to the intelligent control circuit 98, and the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically increase the output pump pressure to P C And continuously supply pressure, increasing the frictional torque between the mover friction plate 52 and the stator friction plate 32, which is greater than the balancing torque to drive the inner shaft 48 to rotate clockwise until the intelligent control circuit 98 monitors that the tool face rotates to around X°, then the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically reduce the output pump pressure to the balancing hydraulic oil pressure P AAnd continuously supply pressure to keep the tool face stationary near X°. The MWD measurement sub monitors that the tool face angle of the current positive displacement motor is near X°, and repeats the "wellhead sends an angle adjustment pressure pulse command B" (b / X - 1) times until the tool face intelligent monitoring circuit 27 monitors that the tool face angle of the positive displacement motor is near b°. The MWD measurement sub monitors that the tool face angle of the current positive displacement motor is near b°, and transmits this monitoring signal to the ground to start directional drilling.

[0103] When the adjusted angle b° is in the range of 180 - 360° clockwise, the wellhead sends an angle adjustment pressure pulse command C, and each command adjusts the reverse rotation by X° (X = 5°). After the pressure sensor 83 measures this command, it transmits this command to the intelligent control circuit 98, and the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically reduce the output pump pressure to P B And continuously supply pressure to reduce the frictional torque between the rotor friction plate 52 and the stator friction plate 32. This frictional torque is less than the balancing torque to drive the inner shaft 48 to rotate counterclockwise until the intelligent control circuit 98 monitors that the tool face rotates to near -X°. Then the intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically increase the output pump pressure to the balanced hydraulic oil pressure P A And continuously supply pressure to keep the tool face stationary near -X°. The MWD measurement sub monitors that the tool face angle of the current positive displacement motor is near -X°, and repeats the "wellhead sends an angle adjustment pressure pulse command C" (b / X - 1) times until the intelligent control circuit 98 monitors that the tool face angle of the positive displacement motor is near b°. The MWD measurement sub monitors that the tool face angle of the current positive displacement motor is near b°, and transmits this monitoring signal to the ground to start directional drilling.

[0104] (4) Working principle of compound drilling:

[0105] When directional drilling is completed and compound drilling is required for well deviation control, after the MWD measurement sub monitors that the tool face of the positive displacement motor reaches the predetermined position II for compound drilling, the wellhead sends a reset pressure pulse command D. After the pressure sensor 83 measures this command, it transmits this command to the intelligent control circuit 98, and the intelligent control circuit 98 automatically sends a hydraulic commutation from the leftmost I position to the rightmost III position to the three - position four - way directional valve 22. The intelligent control circuit 98 automatically controls the motor reduction assembly 62 to drive the hydraulic pump 66 to automatically reduce the output pump pressure to the hydraulic oil pressure P DAnd continuously supply pressure, the hydraulic piston 27 drives the moving spline sleeve 31 to move toward the high-pressure oil chamber 059, and the locking piston 74 moves toward the high-pressure oil chamber 059. The moving spline sleeve 31 continues to move to the initial position and engages with the inner spline groove of the connecting short section 5, which can transmit the torque of the upper drill string to the tool surface of the screw drill. At this time, the locking block 75 moves along the inclined surface of the baffle of the locking piston 74 and the inclined surface of the outer side of the inner shaft 48 to the initial locking position, and the buffer spring 34 returns to the initial position and pushes the movable friction plate 52 and the stator friction plate 32 back to the initial position. At this time, the movable friction plate 52 and the stator friction plate 32 are in a free state, and there is no friction torque between them. The intelligent control circuit 98 rotates continuously clockwise with the upper drill string for 20 seconds or more, and the intelligent control Circuit 98 automatically issues a hydraulic reversal from position III to position II to the three-position four-way directional valve 22, and simultaneously automatically issues a motor shutdown command. The intelligent control circuit 98 enters an automatic sleep mode until it reaches the next directional position, at which point it exits sleep mode and enters a working mode. At this point, the three-position four-way directional valve 22 is in the middle position II, which makes the hydraulic pressures on both sides of the locking piston 74 and the hydraulic piston 27 the same. The return spring 30 and the return spring 71 ensure that the locking piston 74 and the hydraulic piston 27 return to their initial positions. The relief valve 96 ensures that the hydraulic control system can release pressure after an abnormal increase in pressure, ensuring the normal operation of the hydraulic control system. The MWD measuring sub detects that the tool face of the screw drill continuously rotates in the forward direction with the upper drill string, and composite drilling begins.

[0106] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A control tool for a positive displacement motor, characterized in that It includes an inner shaft (48) and a housing. The upper end of the housing is used to connect with the upper drill string. A transmission control part is arranged between the inner shaft (48) and the housing. The transmission control part is used to transfer the torque of the upper drill string to the tool face of the positive displacement motor to smoothly transfer the weight on bit, and is used to balance the reaction torque acting on the outer shell of the positive displacement motor, so that the upper drill string can rotate normally; the lower end of the inner shaft is used to connect with the MWD measuring sub.

2. The control tool for a positive displacement motor according to claim 1, characterized in that The transmission control part includes a buffer spring (34) sleeved on the inner shaft (48) and limited on the inner shaft (48); a friction assembly is limitedly arranged between the inner shaft (48) above the buffer spring (34) and the housing, and a rotating cavity (016) is arranged above the friction assembly; a moving spline sleeve (31) is sleeved on the inner shaft (48) above the rotating cavity (016). The moving spline sleeve (31) can transfer the torque of the housing to the inner shaft (48), and when the moving spline sleeve (31) moves to the rotating cavity (016), the moving spline sleeve (31) cannot transfer the torque of the housing to the inner shaft (48); The upper end of the inner shaft (48) is fixedly and sealingly connected with a support end (25). The lower end of the inner shaft (48) is sealingly connected with the housing. A hydraulic piston (27) is arranged in the sealed hydraulic cavity formed by the inner shaft (48), the support end (25) and the housing. The upper end of the moving spline sleeve (31) is fixedly connected with the hydraulic piston (27). A first return spring (30) is arranged between the moving spline sleeve (31) and the hydraulic piston (27). The lower end of the first return spring (30) is limited by the shoulder of the housing; The support end (25) is fixedly and sealingly connected with an external structure. A circuit board protection chamber (21) is fixedly and sealingly arranged between the support end (25) and the external structure. A drive assembly is fixedly arranged on the support end (25). The drive assembly is located in the inner cavity formed by the support end (25), the external structure and the circuit board protection chamber (21). The drive assembly is connected with a hydraulic control unit. The hydraulic control unit is used to supply oil to the high-pressure oil cavity (059) above the hydraulic piston (27); The friction assembly is used to generate a friction torque under the action of the hydraulic piston (27).

3. The control tool for a positive displacement motor according to claim 2, wherein A locking piston (74) is hermetically arranged in the sealed hydraulic chamber. The locking piston (74) is located between the support end (25) and the hydraulic piston (27). A high-pressure oil chamber (059) is formed between the locking piston (74) and the hydraulic piston (27). The chambers on the side of the locking piston (74) away from the hydraulic piston (27) and the chambers on the side of the hydraulic piston away from the locking piston (74) are both low-pressure oil chambers (041). A second return spring (71) is arranged between the locking piston (74) and the support end (25). A locking block (75) is arranged in the radial movement hole of the hydraulic piston (27). When the hydraulic piston (27) moves axially, the locking block (75) moves radially along the chute slope on the outer surface of the inner shaft (48). After the locking piston (74) moves towards the low-pressure oil chamber (041) away from the hydraulic piston (27) to the unlocking position, the locking piston (74) is disengaged from the locking block (75).

4. The control tool for a positive displacement motor according to claim 2, characterized in that The lower end of the buffer spring (34) is limited by a shoulder arranged on the inner shaft (48), and the upper end of the buffer spring is limited by a first elastic retaining ring (33) fixed on the inner shaft (48). The friction assembly includes a plurality of rotor friction plates (52). A plurality of the rotor friction plates (52) are all arranged above the buffer spring (34). A plurality of the rotor friction plates (52) are key-connected to the inner shaft (48). A stator friction plate (32) is arranged between adjacent two of the rotor friction plates (52). A plurality of the stator friction plates (32) are key-connected to the housing. The lowermost rotor friction plate (52) is limited by a support ring (51) between it and the buffer spring (34). The uppermost rotor friction plate (52) is limited by a second elastic retaining ring (53) fixed on the inner shaft. The rotating chamber (016) is arranged above the uppermost rotor friction plate (52).

5. The control tool for a positive displacement motor according to claim 2, characterized in that, The external structure includes a protection cylinder (20) arranged on the outer side of the support end (25). The support end (25) is fixedly and hermetically connected to the protection cylinder (20). The protection cylinder (20) is fixedly and hermetically connected to the upper end head (15) of the protection chamber. The circuit board protection chamber (21) is arranged in the inner cavity formed by the support end (25) and the upper end head (15) of the protection chamber. The circuit board protection chamber (21) is key-connected to both the support end (25) and the upper end head (15) of the protection chamber, and is hermetically arranged between the circuit board protection chamber (21) and the support end (25) and the upper end head (15) of the protection chamber.

6. The control tool for a positive displacement motor according to claim 5, wherein A pressure sensor (83) is fixedly and sealingly connected to the upper end head (15) of the protection bin. A mud pressure-taking cavity (046), a mud channel (047), and a mud pressure-taking hole (048) which are sequentially communicated are formed in the upper end head (15) of the protection bin. The pressure sensor (83) extends into the mud pressure-taking hole (048). The pressure sensor (83) is used for measuring the mud pressure in the central flow channel of the upper end head (15) of the protection bin. A mud sieve plate (86) is fixed at the mud pressure-taking cavity (046) through an elastic retaining ring (84).

7. The control tool for a positive displacement motor according to claim 5, characterized in that, A first thrust bearing group (14) is sleeved on the upper end head (15) of the protection bin. The lower end of the inner ring of the first thrust bearing group (14) is limited by a shoulder provided on the upper end head (15) of the protection bin. A first fixing ring (13) is threadedly connected to the upper end head (15) of the protection bin. The first fixing ring (13) is used for limiting the upper end of the inner ring of the first thrust bearing group (14). An upper joint (1) is threadedly connected to the upper end of the housing. The housing and the upper joint (1) are fixedly connected. The upper joint (1) is used for connecting with the upper drill string. The upper joint (1) is used for limiting the upper end of the outer ring of the first thrust bearing group (14). The lower end of the outer ring of the first thrust bearing group (14) is limited by a step provided on the housing.

8. The control tool for a positive displacement motor according to claim 3, wherein The drive assembly includes a motor reduction assembly (62). The motor reduction assembly (62) is fixed on a motor reduction assembly fixing frame (65). The output shaft of the motor reduction assembly (62) is connected to the hydraulic control unit through a coupling (64). The cable of the motor reduction assembly (62) is connected to a corresponding joint of a first electrical sealing joint (59). The first electrical sealing joint (59) is fixedly and sealingly connected to a first plug (60). The first plug (60) is fixedly and sealingly connected to a motor reduction assembly protection cylinder (63). The motor reduction assembly protection cylinder (63) is fixedly and sealingly connected to one end of a coupling nipple (68). The other end of the coupling nipple (68) is fixedly and sealingly connected to the support end head (25).

9. The control tool for a positive displacement motor according to claim 8, wherein The hydraulic control unit includes a hydraulic pump 66 fixedly connected to the coupling (64). One end of the hydraulic oil outlet of the hydraulic pump 66 is fixedly and sealingly connected to one end of an oil outlet pipe (67). An oil outlet pipe central hole (037) is provided on the oil outlet pipe (67). The first electrical sealing joint (59), the first plug (60), the motor reduction assembly protection cylinder (63), the oil outlet pipe (67), the coupling nut (68) and the support end (25) form a closed hydraulic oil tank. The hydraulic pump 66 is fixed on the motor reduction assembly fixing bracket (65). A three-position four-way directional control valve (22) is sealingly arranged in the hydraulic reversing through hole of the support end (25). An overflow valve (96) is fixedly and sealingly connected in the overflow hole of the support end (25). A check valve (69) is fixedly and sealingly connected to the support end (25). The hydraulic oil outlet of the hydraulic pump 66 communicates with the third communication hole (08) of the three-position four-way directional control valve (22). The check valve is arranged between the hydraulic oil outlet of the hydraulic pump 66 and the third communication hole (08). The low-pressure oil chamber (041) communicates with the fourth communication hole (05) of the three-position four-way directional control valve (22). The first communication hole (011) of the three-position four-way directional control valve (22) communicates with the hydraulic oil tank. One end of the overflow valve is connected between the first communication hole (011) and the hydraulic oil tank. The other end of the overflow valve is connected between the inlet of the check valve (69) and the hydraulic oil outlet of the hydraulic pump (66). The second communication hole (09) of the three-position four-way directional control valve (22) communicates with the high-pressure oil chamber (059).

10. The control tool for a positive displacement motor according to claim 9, wherein The support end (25) is fixedly and sealingly connected with a high-pressure pressure sensor (93) which is used to detect the pressure of the high-pressure oil chamber (059); the support end (25) is fixedly and sealingly connected with a low-pressure pressure sensor (56) which is used to measure the liquid pressure of the low-pressure oil chamber (041); a high-pressure oil main channel (051) and a high-pressure oil through hole (052) are provided on the support end (25). The second communication hole (09) of the three-position four-way directional control valve (22) communicates with the high-pressure oil chamber (059) through the high-pressure oil main channel (051) and the high-pressure oil through hole (052).

11. The control tool for a positive displacement motor according to claim 10, characterized in that, It also includes a control circuit: The control circuit includes a motor drive circuit protection cylinder (79). One end of the motor drive circuit protection cylinder (79) is fixedly and sealingly connected to a second power sealing joint (77). The other end of the motor drive circuit protection cylinder (79) is fixedly and sealingly connected to a second plug (78). The second plug (78) is fixedly and sealingly connected to a third power sealing joint (82). The motor drive circuit protection cylinder (79) is fixedly connected to the circuit board protection chamber (21). A circuit support plate (81) is fixedly connected inside the motor drive circuit protection cylinder (79). A motor drive circuit (80) is fixedly connected to the circuit support plate (81). The second power sealing joint (77), the third power sealing joint (82), and the motor drive circuit (80) are electrically connected. A power supply battery (91), a wireless communication circuit (97), and an intelligent control circuit (98) are fixedly connected to the circuit board protection chamber (21). The low-pressure pressure sensor (56), the high-pressure pressure sensor (93), the three-position four-way directional control valve (22), the motor drive circuit (80), and the power supply battery (91) are all connected to the intelligent control circuit (98).

12. The control tool for a positive displacement motor according to any one of claims 1-11, characterized in that, The lower end of the inner shaft is fixedly connected to a transmission shaft (11). The transmission shaft is used to connect to the MWD measuring sub. The lower end of the housing is fixedly connected to a lower housing (8). An upper moving coil housing (37), an upper moving ring alloy sleeve (38), a second thrust bearing set (39), a half ring (40), a lower static alloy (41), a lower moving alloy (42), a spacer ring (43), a pressure-bearing ring (44), an upper static coil housing (45), an upper static coil alloy sleeve (46), and a lower moving housing (10) are sleeved on the transmission shaft (11). The upper moving coil housing (37) and the lower moving housing (10) are fixedly connected to the transmission shaft (11). The upper moving ring alloy sleeve (38) is fixed on the upper moving coil housing (37). The upper static coil alloy sleeve (46) is sleeved outside the upper moving ring alloy sleeve (38), and a dynamic friction pair structure is formed between them. The upper static coil alloy sleeve (46) is fixedly connected to the upper static coil housing (45). The lower moving alloy (42) is fixed on the lower moving housing (10). The lower static alloy (41) is fixed on a lower static housing (9). The lower static housing (9) is fixedly connected to the lower housing (8). A dynamic friction pair structure is formed between the lower moving alloy (42) and the lower static alloy (41). Wherein, a second thrust bearing set (39) is arranged between the transmission shaft (11) and the lower housing (8). The inner ring of the second thrust bearing set (39) is limited by the pressure-bearing ring (44) and the upper moving coil housing (37). The outer ring of the second thrust bearing set (39) is limited by the spacer ring (43) and the upper static coil housing (45).

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