Rotary angle control and braking device for directional drilling power head

Abstract

The present application belongs to the technical field of coal mine drilling machine, and relates to a rotating angle control and braking device for a power head of a directional drilling machine, comprising a transmission shaft, a driving piston, a fixed gear disc, a movable gear disc, an end cover, a rotating seat, a connecting seat and a rotating reducer with self-locking function. One end of the transmission shaft is fixedly connected with a driving shaft in the power head of the directional drilling machine. The driving piston, the fixed gear disc and the movable gear disc are all sleeved on the transmission shaft, and the fixed gear disc is fixedly connected with the transmission shaft in the circumferential direction. A spring is arranged between the movable gear disc and the end cover. The helical gears arranged between the movable gear disc and the fixed gear disc are engaged under the action of the spring. A sealing cavity is arranged between the connecting seat and the driving piston. The driving piston and the movable gear disc are driven to move towards the end cover by injecting oil into the sealing cavity to release the engagement of the helical gears. The rotating seat is fixedly connected with the outside of the movable gear disc in the circumferential direction and is fixedly connected with the output disc of the rotating reducer.

Description

Technical Field

[0001] This invention belongs to the field of coal mine drilling rig technology, and relates to a rotation angle control and braking device for the power head of a directional drilling rig. Background Technology

[0002] During directional drilling, the drilling trajectory direction is typically changed by adjusting the tool face angle. Existing directional drilling rigs have power heads that are essentially the same as traditional drilling rigs, lacking a device for accurately controlling the rotation angle. Tool face angle adjustment relies on a drilling rotary motor, which rotates at high speeds. Combined with the large inertia of the power head transmission system, this results in poor control accuracy and low adjustment efficiency. Existing directional drilling rigs usually have only one (or a set of) motors, namely the main motor that drives the spindle. Therefore, the main motor is also used to drive the spindle when adjusting the tool face angle. However, during drilling, multiple drill rods are inevitably connected by threads inside the hole. Therefore, adjusting the tool face angle can only be done by using the main motor to drive the spindle and drill rods in the forward direction; reversing the direction could loosen the threaded connections of the drill rods inside the hole, leading to drill loss. Based on the drilling speed requirements of coal mines, the main motor drives the drill rods at a relatively high speed, even at low speeds of approximately 50 r / min (300° / s). Therefore, the adjustment accuracy of this system is very low. In addition, the power head transmission system (spindle, gears, etc.) has a large mass and inertia, and often cannot stop accurately when the tool face angle is adjusted to the correct position. Once the preset angle is missed, it must rotate forward about one revolution and readjust, which leads to very low adjustment efficiency and inaccuracy.

[0003] Chinese patent CN103061669B is a typical representative of existing technology. It discloses a power head for a large-diameter through-hole directional drilling rig in coal mines with braking function. Its key features include a motor, gearbox, main shaft, I-axis, and chuck. The motor is connected to the main shaft via the gearbox. The I-axis meshes with the main shaft via gears in the gearbox. The chuck is located at the front end of the main shaft. A support ring is installed at the rear end of the main shaft. An oil distribution sleeve is fitted on the main shaft. The I-axis is connected to a brake via the gearbox. The brake adopts a wet friction disc structure. The brake's dial is connected to the I-axis of the power head via a spline. The active friction plate... The fork-like connection of the dial, the passive friction plates connected to the end cover shaft fixed on the brake end cover via splines, and the brake equipped with a piston rod, on which six piston rod springs are evenly distributed in a circle, are mounted. A pressure plate is located at the front end of the piston rod, with six active friction plates and five passive friction plates stacked on top of each other at the front end of the pressure plate. The rear end of the piston rod abuts against the front end of the end cover shaft, and a pressure cap is installed in a slot at the front end of the end cover shaft, with a shaft end spring at the bottom of the pressure cap; a locking nut is located at the front end of the end cover shaft; the oil drain port of the motor is connected to the lower oil port of the brake housing, and the oil flows back to the oil tank through the upper oil port of the brake housing. The piston rod springs are tightly fitted with the piston rod. This allows the large-diameter power head of the coal mine directional drilling rig to have a spindle braking function and simultaneously meet both rotary drilling and bottom-hole motor directional drilling processes. However, the power head of the large-diameter directional drilling rig in this coal mine does not have a device to accurately control the rotation angle of the tool face. Adjusting the rotation angle of the tool face still requires the use of the spindle motor, so the tool face angle cannot be precisely adjusted. Secondly, its braking device has a single function. Not only does it not have an angle adjustment function, but it also uses the traditional friction plate method. It has many vulnerable parts inside, which require frequent replacement of parts and maintenance, making maintenance difficult in later operation. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a rotation angle control and braking device for the power head of a directional drilling rig, so as to solve the problem that the tool face angle cannot be accurately adjusted in the existing directional drilling process.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A rotation angle control and braking device for a power head of a directional drilling rig is provided, which includes a drive shaft, a drive piston, a fixed gear disc, a movable gear disc, an end cover, a rotary seat, a connecting seat, and a rotary reducer with a self-locking function. One end of the drive shaft is circumferentially fixedly connected to the drive shaft of the main motor in the directional drilling rig power head, and the other end is rotatably connected to the end cover. The drive piston, the fixed gear disc, and the movable gear disc are all sleeved on the drive shaft, and the drive piston is located at the end of the drive shaft closer to the drive shaft. The end of the drive piston away from the drive shaft is connected to the movable gear disc. The fixed gear disc is circumferentially fixedly connected to the drive shaft, and the fixed gear disc is located between the drive piston and the movable gear disc.

[0007] The movable gear disk is a disc-shaped part with a central through hole, and the central through hole is a stepped through hole. The stepped through hole has a large diameter through hole on the side facing the end cover. The movable gear disk is sleeved on the end cover and slidably connected through the large diameter through hole. The end face of the movable gear disk facing the driving piston is provided with a first helical tooth distributed along the circumference. The fixed gear disk is provided with a second helical tooth that meshes with the first helical tooth. A spring is provided between the inner end face of the large diameter through hole and the end face of the end cover corresponding to the inner end face, so that the first helical tooth and the second helical tooth mesh under the thrust of the spring.

[0008] The outer circular surface of the movable gear disk is provided with evenly distributed bosses. The rotary seat is sleeved on the movable gear disk and is provided with grooves that match the bosses so as to be circumferentially fixedly connected to the movable gear disk. One end of the rotary seat is provided with a rotary reducer connecting plate that is fixedly connected to the output plate of the rotary reducer so as to transmit the rotation of the output plate in the rotary reducer to the movable gear disk.

[0009] The connecting seat is sleeved on the drive piston. The outer circle of the connecting seat is divided into three diameters, with the middle section having the largest diameter. The two end faces of the middle section are respectively connected to the directional drilling rig power head and the rotary reducer to achieve relative axial positioning between the directional drilling rig power head, the connecting seat, and the rotary reducer. The inner diameter of the connecting seat is divided into three apertures, with the two apertures furthest from the directional drilling rig power head matching the outer diameter of the drive piston and sleeved on the drive piston. The output disc of the rotary reducer is coaxial with the rotary seat.

[0010] The drive piston is a two-stage stepped shaft. Its small-diameter end has a sealing groove on its outer circle. A sealing ring is installed in the sealing groove and cooperates with the corresponding position of the connecting seat fitted on it to form a first seal. The large-diameter end cooperates with the sealing ring installed at the corresponding position of the connecting seat to form a second seal. A sealing cavity is formed between the first seal and the second seal between the drive piston and the connecting seat. An oil inlet communicating with the sealing cavity is provided on the connecting seat so that the drive piston pushes the moving gear plate towards the end cover under the action of hydraulic oil.

[0011] Furthermore, a transmission piston is provided between the drive piston and the movable gear disk. The transmission piston is sleeved on the transmission shaft and slidably connected. One end of the transmission piston is connected to the drive piston, and the other end is connected to the movable gear disk to transmit the thrust of the drive piston.

[0012] Furthermore, the rotary seat is cylindrical, and an end cap connecting plate is provided at one end away from the rotary reducer connecting plate to be fixedly connected to the end cap.

[0013] Furthermore, the fixed gear disc has a gear disc and a fixed shaft located at the center of the gear disc. The second helical tooth is disposed on the gear disc. The fixed shaft is inserted into the central through hole of the movable gear disc and a keyway is provided in the fixed shaft so that the fixed gear disc is circumferentially fixedly connected to the transmission shaft by a key connection.

[0014] Furthermore, the rotary reducer is a worm gear rotary reducer with a self-locking function.

[0015] Furthermore, the transmission shaft and the drive shaft are connected by a spline.

[0016] Furthermore, the end cover is a three-tiered hollow disc structure, which is sleeved on the drive shaft by bearings. Its maximum outer diameter section is provided with a flange connected to the rotary seat, and the maximum outer diameter section is located at the end away from the drive shaft. The middle diameter section is used to support the rotary seat and limit the axial movement distance of the moving gear plate. The minimum diameter section is axially slidably connected to the large diameter through hole of the moving gear plate, and the end face of the minimum diameter section is provided with a plurality of spring mounting holes evenly distributed along the circumference for installing springs.

[0017] Furthermore, the drive shaft is housed within the gearbox in the power head of the directional drilling rig. One end face of the middle section of the connecting seat is connected to the gearbox. A section of the connecting seat near the gearbox is inserted into the gearbox and serves as an axial stop for the bearing mounted on the drive shaft. A section near the rotary reducer extends into the rotary reducer for installation guidance.

[0018] Furthermore, the smaller diameter end of the drive piston is the end closest to the drive shaft.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention provides a rotation angle control and braking device for the power head of a directional drilling rig. It simultaneously features accurate tool face angle adjustment and drive shaft locking to prevent rotation. This achieves accurate and efficient tool face angle adjustment while preventing the power head spindle from rebounding due to drill rod elastic deformation. It solves the problem in existing drilling rigs where the lack of a dedicated tool face angle adjustment device results in low trajectory adjustment accuracy and efficiency, hindering automatic directional drilling. Furthermore, it significantly reduces the driving force required for tool face angle adjustment, resulting in better energy savings. It simplifies the structure of the main motor's rotation braking device, converting the functions of many internal parts into an external rotary reducer, thus eliminating the need for numerous friction plates, significantly reducing maintenance difficulty, and minimizing the consumption of vulnerable parts.

[0021] Secondly, the present invention preferably uses a worm gear reducer with a self-locking function. The transmission ratio of existing worm gear reducers can reach more than 1:100. However, the minimum spindle speed driven by the main motor in the prior art is 50 r / min (300° / s). This rotation angle control and braking device can control the spindle output speed to within 1 / 100 of that in the prior art (≤3° / s) through the worm gear reducer. This will be very beneficial for accurate adjustment and timely stopping, and will greatly improve the tool face angle adjustment accuracy and efficiency.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0024] Figure 1 This is a schematic diagram of a rotation angle control and braking device for a directional drilling rig power head according to the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the driving piston in this invention;

[0026] Figure 3 This is a schematic diagram of the structure of the movable gear disk in this invention;

[0027] Figure 4 This is a schematic diagram of the fixed gear disc structure in this invention;

[0028] Figure 5 This is a schematic diagram of the end cap structure in this invention;

[0029] Figure 6 This is a schematic diagram of the rotary seat in this invention;

[0030] Figure 7 This is a schematic diagram of the connecting seat in the present invention;

[0031] Figure 8 for Figure 1 A magnified view of a portion of the image.

[0032] Reference numerals: 1-Drive shaft, 2-Drive piston, 201-Sealing groove, 202-Outer diameter of large diameter end, 3-Rotary reducer, 4-Drive piston, 5-Fixed gear disc, 501-Gear disc, 502-Fixed shaft, 6-Moving gear disc, 601-Boss, 602-First helical tooth, 7-End cover, 701-Maximum outer diameter section, 702-Intermediate diameter section, 703-Minimum diameter section, 704-Spring mounting hole 8-Bearing cap, 9-Spring, 10-Slewing seat, 1001-Slewing reducer connecting plate, 1002-End cover connecting plate, 1003-Groove, 11-Flat key, 12-Connecting seat, 1201-Left section, 1202-Middle section, 1203-Right section, 1204-Left inner section, 1205-Middle inner section, 1206-Right inner section, 13-Drive shaft, 14-Gearbox, 15-Main motor. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0036] Please see Figures 1 to 8 This invention relates to a rotation angle control and braking device for a directional drilling rig power head, comprising a drive shaft 1, a rotary seat 10, a connecting seat 12, a bearing cover 8, a spring 9, a drive piston 2, a transmission piston 4, a fixed gear disc 5, a movable gear disc 6, and an end cover 7, sequentially mounted on the drive shaft 1 from left to right, and a rotary reducer 3 with a self-locking function. The transmission ratio of the rotary reducer 3 is greater than the transmission ratio of the gearbox 14 in the directional drilling rig power head. The left end of the drive shaft 1 is splined and inserted into the drive shaft 13 of the main motor 15 in the directional drilling rig power head. The drive shaft 13 has a connection point with the drive shaft 1. The keyway on the drive shaft 1 matches the spline, so that the drive shaft 1 and the drive shaft 13 form a spline connection, thereby forming a circumferential fixed connection. The right end of the drive shaft 1 is connected to the fixed gear disk 5 sleeved on the drive shaft 1 by a flat key 11 to form a circumferential fixed connection, and is rotatably connected to the end cover 7 by a bearing. The end cover 7 is located on the side of the fixed gear disk 5 away from the drive shaft 13 and on the right side of the fixed gear disk 5. Spacer sleeves are provided on both sides of the bearing, and a bearing cover 8 is provided on the side of the end cover 7 away from the fixed gear disk 5, which is fixedly connected by bolts to position the bearing.

[0037] The drive piston 2 is a hollow two-stage stepped shaft, which is sleeved on the drive shaft 1. The outer circle of the small diameter end is provided with a sealing groove 201, in which a sealing ring is installed. It cooperates with the inner hole of the corresponding position of the connecting seat 12 sleeved on it to form a first seal. The outer circle 202 of the large diameter end cooperates with the sealing ring in the sealing ring mounting groove at the corresponding position on the connecting seat 12 to form a second seal. The first seal and the second seal form a sealing cavity Y between the drive piston 2 and the connecting seat 12. The connecting seat 12 is provided with an oil inlet that communicates with the sealing cavity Y. Hydraulic oil enters the sealing cavity Y through the oil inlet on the connecting seat 12, pushing the drive piston 2 from the small diameter end to the large diameter end. The small diameter end of the drive piston 2 is the end closer to the drive shaft 13.

[0038] Preferably, the drive piston 2 has two stepped inner holes, and the side facing the end cover 7 has a large-diameter inner hole. The drive shaft 1 has a corresponding shoulder that matches the two stepped inner holes, thereby limiting the displacement distance of the drive piston 2 in the axial direction.

[0039] The transmission piston 4 is a disc-shaped part with a central through hole. It is sleeved on the transmission shaft 1, with its left end in contact with the large-diameter end of the drive piston 2 and its right end in contact with the moving gear disk 6. Its main function is to transmit the driving force of the drive piston 2 (the driving force for displacement to the right) to the moving gear disk 6, causing it to move towards... Figure 1 The right end of the movement;

[0040] The main body of the movable gear disk 6 is a disc-shaped part with a central through hole. The middle is a stepped through hole for the transmission shaft 1 and the fixed shaft 502 of the fixed gear disk 5 to pass through. The through hole facing the end cover is a large-diameter through hole. The inner end face of the large-diameter through hole is used to bear the end thrust of the spring 9. The end face of the movable gear disk 6 facing the transmission piston 4 is provided with first helical teeth 602 distributed along the circumference, and the outer circular surface is provided with evenly distributed bosses 601, which cooperate with the groove 1003 in the inner hole of the rotary seat 10 to transmit the rotation of the rotary reducer 3 connected to the rotary seat 10.

[0041] The fixed gear disk 5 has a gear disk 501 and a fixed shaft 502 located at the center of the gear disk 501. The fixed shaft 502 is a hollow shaft with a keyway in its internal through hole, allowing the fixed gear disk 5 to form a keyed connection with the transmission shaft 1, thereby fixing the connection in the circumferential direction and restricting rotation between the fixed gear disk 5 and the transmission shaft 1. The end face of the gear disk 501 facing the movable gear disk 6 has second helical teeth distributed circumferentially, which mesh with the first helical teeth 602 of the movable gear disk 6. Specifically, the fixed gear disk 5 is fixed to the transmission shaft 1 by a flat key 11 to prevent relative rotation between the fixed gear disk 5 and the transmission shaft 1. The two ends of the fixed gear disk 5 are further axially stopped by the shaft shoulders and spacer sleeves of the transmission shaft 1.

[0042] The end cover 7 has a three-tiered hollow disc structure, which is mounted on the drive shaft 1 via bearings. The largest outer diameter section 701 is provided with a flange connected to the rotary seat 10 mounted on the movable gear disc 6 and a flange connected to the bearing cover 8. The middle diameter section 702 is used to cooperate with the rotary seat 10 and limit the axial movement distance of the movable gear disc 6. The smallest diameter section 703 is used to cooperate with the movable gear disc 6, that is, the large diameter through hole in the movable gear disc 6 matches the outer circle of the smallest diameter section 703 and forms an axial sliding connection. The end face of the smallest diameter section 703 is provided with multiple circumferentially distributed spring mounting holes 704 for mounting springs 9. The smallest diameter section 703 is the end of the end cover 7 closest to the drive shaft 13. The bearing cover 8 is fixed to the outside of the end cover 7 with bolts to limit the axial movement of the bearing. The spring 9 is installed between the end cover 7 and the movable gear disc 6 through the mounting holes 704 to provide a thrust to the movable gear disc 6 toward the fixed gear disc 5.

[0043] The rotary seat 10 is cylindrical in shape and is fitted on the outside of the movable gear disk 6. Its left end is a rotary reducer connecting plate 1001, which is used to connect the output plate of the rotary reducer 3 with self-locking function. Its right end is an end cover connecting plate 1002, which is used to install the end cover 7 and is connected with the middle diameter section 702 in the end cover 7 to leave space for installing the movable gear disk 6. The interior of the rotary seat 10 is a through hole and has a groove 1003 corresponding to the boss 601 of the movable gear disk 6. The boss 601 and the groove 1003 form a circumferential fixed connection between the rotary seat 10 and the movable gear disk 6, and the movable gear disk 6 can be axially displaced relative to the rotary seat 10.

[0044] The connecting seat 12 is used to connect the rotation angle control and braking device to the transmission 14 in the power head of the directional drilling rig. The transmission 14 is sleeved on the drive shaft 13 and is mainly used to transmit the torque and rotation of the drive shaft 13 to the spindle or drill rod. The connecting seat 12 is a hollow cylinder with its outer circle divided into three diameters. The diameter of the middle section 1202 is the largest to form a central protrusion. The end faces on both sides of the middle section 1202 are respectively attached to and fixedly connected to the transmission 14 and the rotary reducer 3 to achieve relative axial positioning between the three components. The left section 1201 (the end closer to the drive shaft 13) is inserted into the cavity of the transmission 14 and connects with the bearing sleeved on the drive shaft 13, serving as an axial stop for the bearing sleeved on the drive shaft 13. It is provided with a sealing groove, and the cavity of the transmission 14 is sealed by installing a sealing ring. The right section 1203 extends into the rotary reducer 3 to facilitate the installation of the rotary reducer 3 as a guide.

[0045] The inner diameter of the connecting seat 12 is also divided into three levels. The inner diameter of the left inner section 1204 matches the drive shaft 1 and is provided with a sealing groove, which provides secondary sealing to the transmission 14 by installing a sealing ring. The middle inner section 1205 and the right inner section 1206 match the outer diameters of the two-stage stepped shaft of the drive piston 2, respectively. A sealing ring mounting groove is provided on the right inner section 1206, and a sealing ring is installed thereon. Thus, the middle inner section 1205 and the right inner section 1206 match the outer diameters of the small and large diameter ends of the drive piston 2, respectively, forming a first seal and a second seal, thereby forming a sealing cavity Y. A sealing ring is installed corresponding to the middle inner section 1205. The sealing groove 201 of the sealing ring is provided on the drive piston 2 to form a first seal. The right inner section 1206 is provided with a sealing groove and a sealing ring is installed to match the large diameter outer circle 202 to form a second seal. The first seal and the second seal form a sealing cavity Y between the connecting seat 12 and the drive piston 2. An oil inlet is provided on the outer surface of the connecting seat 12 at a position corresponding to the sealing cavity Y. Hydraulic oil enters the sealing cavity Y through the oil inlet on the connecting seat 12, pushing the drive piston 2 to move from the right end, and then pushing the transmission piston 4 and the moving gear 6. The moving gear 6 further compresses the spring 9, thereby releasing the helical tooth mesh between the moving gear 6 and the fixed gear 5.

[0046] The rotary reducer 3 is sleeved on the right section 1203 of the connecting seat 12 and fixedly connected to the middle section 1202 of the connecting seat 12. The output disc (such as a gear disc or worm gear) of the rotary reducer 3 is fixedly connected to the rotary seat 10 by bolts, thereby restricting the relative rotation between the output disc of the rotary reducer 3 and the rotary seat 10. The rotary reducer 3 has two main functions: first, it drives the drive shaft 13 to rotate relatively slowly (compared to the drive of the main motor 15) through the transmission shaft 1, and transmits this rotation through the gearbox 14, thereby accurately controlling the output rotation angle. Second, because the rotary reducer 3 has a self-locking function, and the self-locking torque of the rotary reducer 3 is greater than the output torque of the main motor 15, it can prevent the main motor 15 from driving the drive shaft 13 to rotate under the locking condition, thereby achieving the locking and anti-rotation of the entire gearbox 14.

[0047] Preferably, the rotary reducer 3 is a worm gear rotary reducer with a self-locking function. That is, the rotary reducer connecting plate 1001 connects to the worm gear, which serves as the output plate in the worm gear rotary reducer, and the worm gear is sleeved on the transmission shaft 1 through the connecting seat 12 and the drive piston 2 to ensure the synchronous rotation of the worm gear and the rotary seat 10. The transmission ratio of existing worm gear rotary reducers can reach more than 1:100. However, the minimum speed of the spindle driven by the main motor 15 in the prior art (the spindle is driven by the gearbox 14) is at least 50 r / min (300° / s). Therefore, this rotation angle control and braking device can control the spindle output speed to within 1 / 100 of the prior art (≤3° / s) through the worm gear rotary reducer, which will be very beneficial for accurate adjustment and timely stopping, and greatly improve the tool face angle adjustment accuracy and adjustment efficiency.

[0048] Specifically, the worm gear rotary reducer includes a drive source, a worm, a worm wheel, and a slewing bearing. The slewing bearing is sleeved on the connecting seat and fixedly connected by bolts. The worm wheel is rotatably connected to the outer circle of the slewing bearing via a raceway and engages with the worm, thereby achieving coaxiality between the output disc (i.e., the worm wheel) of the rotary reducer and the slewing bearing. The drive source is connected to one end of the worm to drive its rotation. Because worm gear transmission has a reverse self-locking characteristic, it can achieve reverse self-locking, meaning that only the worm can drive the worm wheel, and the worm wheel cannot drive the worm, thus providing a self-locking function. The drive source is an electric motor or a hydraulic motor; in this embodiment, a hydraulic motor is preferred to suit complex underground coal mine operations.

[0049] In another embodiment, the rotary reducer is any one of the rotary reducers such as RV reducer and harmonic reducer, and the structure of the rotary reducer 3 described above, which serves as the output disk (or rotary disk), is fixedly connected to the rotary base 10.

[0050] The aforementioned rotation angle control and braking device for the power head of a directional drilling rig has two working conditions, and its working principle is as follows:

[0051] Locked-in condition: No pressurized oil enters the sealed cavity Y formed by the drive piston 2 and the connecting seat 12 from the oil inlet of the connecting seat 12. This rotation angle control and braking device is not driven by externally supplied pressurized oil. The spring 9 always applies an axial force towards the fixed gear 5 to the moving gear 6, keeping the helical teeth of the moving gear 6 meshing with the helical teeth of the fixed gear 5. At this time, the main motor 15 and the drive shaft 13 are connected to the rotary reducer 3 through the transmission shaft 1, the fixed gear 5, the moving gear 6, and the rotary seat 10. The rotary reducer 3 is within its working capacity range. It has a self-locking function (i.e., the self-locking torque of the rotary reducer 3 is greater than the output torque of the main motor 15), thereby locking the transmission system of the gearbox 14, and the main motor 15 cannot transmit motion through the gearbox 14; however, if the rotary reducer 3 is driven at this time, the rotary reducer 3 can drive the drive shaft 13 to rotate at a relatively slow speed (compared to the main motor drive), and transmit this rotation and torque through the gearbox 14, thereby accurately controlling the rotation angle of the spindle and drill rod, and thus making precise and efficient adjustment of the tool face angle.

[0052] Unlocking condition: Pressurized oil is injected into the sealed cavity Y between the drive piston 2 and the connecting seat 12 through the oil inlet of the connecting seat 12. The hydraulic pressure drives the drive piston 2 and pushes the transmission piston 4 and the moving gear 6 in the direction of disengaging from the fixed gear 5. At this time, the spring 9 is compressed by the moving gear 6 and contracts. The helical teeth of the moving gear 6 and the fixed gear 5 are disengaged. The self-locking effect of the rotary reducer 3 cannot be transmitted to the transmission shaft 1, the drive shaft 13 and the main motor 15. Therefore, the main motor 15 can drive the drive shaft 13 to rotate, and then output rotation and torque through the transmission 14.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A rotation angle control and braking device for a power head of a directional drilling rig, characterized in that: The system includes a drive shaft, a drive piston, a fixed gear disc, a movable gear disc, an end cover, a rotary seat, a connecting seat, and a rotary reducer with a self-locking function. One end of the drive shaft is circumferentially fixedly connected to the drive shaft of the main motor in the directional drilling rig's power head, and the other end is rotatably connected to the end cover. The drive piston, fixed gear disc, and movable gear disc are all sleeved on the drive shaft, with the drive piston located at the end of the drive shaft closest to the drive shaft and the end of the drive piston away from the drive shaft connected to the movable gear disc. The fixed gear disc is circumferentially fixedly connected to the drive shaft and is located between the drive piston and the movable gear disc. The movable gear disk is a disc-shaped part with a central through hole, and the central through hole is a stepped through hole. The stepped through hole has a large diameter through hole on the side facing the end cover. The movable gear disk is sleeved on the end cover and slidably connected through the large diameter through hole. The end face of the movable gear disk facing the driving piston is provided with a first helical tooth distributed along the circumference. The fixed gear disk is provided with a second helical tooth that meshes with the first helical tooth. A spring is provided between the inner end face of the large diameter through hole and the end face of the end cover corresponding to the inner end face, so that the first helical tooth and the second helical tooth mesh under the thrust of the spring. The outer circular surface of the movable gear disk is provided with evenly distributed protrusions. The rotary seat is sleeved on the movable gear disk and is provided with grooves that match the protrusions so as to be circumferentially fixedly connected to the movable gear disk. One end of the rotary seat is provided with a rotary reducer connecting plate that is fixedly connected to the output plate of the rotary reducer so as to transmit the rotation of the output plate in the rotary reducer to the movable gear disk. The connecting seat is sleeved on the drive piston. The outer circle of the connecting seat is divided into three diameters, with the middle section having the largest diameter. The two end faces of the middle section are respectively connected to the directional drilling rig power head and the rotary reducer to achieve relative axial positioning between the directional drilling rig power head, the connecting seat, and the rotary reducer. The inner diameter of the connecting seat is divided into three apertures, with the two apertures furthest from the directional drilling rig power head matching the outer diameter of the drive piston and sleeved on the drive piston. The output disc of the rotary reducer is coaxial with the rotary seat. The drive piston is a two-stage stepped shaft. Its small-diameter end has a sealing groove on its outer circle. A sealing ring is installed in the sealing groove and cooperates with the corresponding position of the connecting seat fitted on it to form a first seal. The large-diameter end cooperates with the sealing ring installed at the corresponding position of the connecting seat to form a second seal. A sealing cavity is formed between the first seal and the second seal between the drive piston and the connecting seat. An oil inlet communicating with the sealing cavity is provided on the connecting seat so that the drive piston pushes the moving gear plate towards the end cover under the action of hydraulic oil.

2. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: A transmission piston is also provided between the drive piston and the movable gear disk. The transmission piston is sleeved on the transmission shaft and slidably connected. One end of the transmission piston is connected to the drive piston, and the other end is connected to the movable gear disk to transmit the thrust of the drive piston.

3. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The rotary seat is cylindrical, and an end cap connecting plate is provided at one end away from the rotary reducer connecting plate to be fixedly connected to the end cap.

4. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The fixed gear disk has a gear disk and a fixed shaft located at the center of the gear disk. The second helical tooth is disposed on the gear disk. The fixed shaft is inserted into the central through hole of the movable gear disk and a keyway is provided in the fixed shaft so that the fixed gear disk is circumferentially fixedly connected to the transmission shaft by a key connection.

5. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The rotary reducer is a worm gear rotary reducer with a self-locking function.

6. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The transmission shaft and the drive shaft are connected by a spline.

7. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The end cover is a three-tiered hollow disc structure, which is mounted on the drive shaft via bearings. Its maximum outer diameter section has a flange connected to the rotary seat, and the maximum outer diameter section is located at the end away from the drive shaft. The middle diameter section is used to support the rotary seat and limit the axial movement distance of the moving gear plate. The minimum diameter section is axially slidably connected to the large diameter through hole of the moving gear plate, and the end face of the minimum diameter section has several spring mounting holes evenly distributed along the circumference for installing springs.

8. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The drive shaft is housed in the gearbox within the power head of the directional drilling rig. One end face of the middle section of the connecting seat is connected to the gearbox. A section of the connecting seat near the gearbox is inserted into the gearbox and serves as an axial stop for the bearing mounted on the drive shaft. A section near the rotary reducer extends into the rotary reducer for installation guidance.

9. The rotation angle control and braking device for the power head of a directional drilling rig according to claim 1, characterized in that: The smaller diameter end of the drive piston is the end closest to the drive shaft.

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