Long-range pumping unit with double planet wheels and transmission belt wheel

Abstract

The invention relates to a long-range pumping unit with a double-planet-wheel transmission belt wheel. The long-range pumping unit comprises a rack, a double-planet-wheel transmission set, a belt wheel set and a pumping rod. The double-planet-wheel transmission set is arranged on the left side of the rack. The belt wheel set is connected between the double-planet-wheel transmission set and the top of the right side of the rack. The sucker rod is connected with the outer end of the belt wheel set. The pump is large in transmission ratio, high in efficiency, high in bearing capacity, long in stroke, high in pump efficiency, good in variable load balance, compact in structure and better in sealing and lubricating performance.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction equipment, and particularly to a double planetary gear drive pulley long-stroke pumping unit. Background Art

[0002] In the working condition of oil extraction from shallow wells, the beam pumping unit with sucker rod has been widely used in the later stage of oil fields in various countries around the world due to its advantages of continuous and non-impact sucker rod commutation process, simple structure and reliability.

[0003] In the working condition of oil extraction from deep wells greater than 2000m, the elastic elongation of the sucker rod is relatively large. It is necessary to increase the stroke of the sucker rod to effectively improve the pump efficiency of the pumping unit and reduce energy consumption. Directly increasing the stroke of the sucker rod of the beam pumping unit with sucker rod will cause the length and total weight of its beam to increase exponentially. For example, for a conventional beam pumping unit with a stroke of 1.5m to 6m, the machine length is about 6m to 24m. This will cause the manufacturing cost, materials, driving torque and floor area to increase exponentially, and make the safety performance worse. In the oil field working condition, sand or inclusions between the belt and the pulley of the beam pumping unit are likely to cause slipping or belt-off. Water accumulation on the ground soaking the motor is likely to conduct electricity and damage the motor. The mixture of ice, rain and snow is likely to cause the belt to freeze and slip or belt-off. The high-speed and large traction belt drive is prone to aging and belt breakage under the working condition of long-term exposure to wind, sun, rain and snow. Therefore, experts in the technical field of oil extraction equipment have been constantly working hard to design and develop various long-stroke pumping units, aiming to improve the pump efficiency of the pumping unit, extend the working life, improve the lubrication and sealing conditions, reduce the manufacturing cost, save energy and electricity, and reduce the floor area.

[0004] Some typical existing patent technologies for pumping units in this regard are as follows: The invention patent authorized in 2025 discloses a front-mounted pumping unit that uses a reducer and a motor as a counterweight. One end of the downstream beam is connected to the reducer and swings, and the other end drives the upstream beam to drive the sucker rod to reciprocate. The invention patents CN118998544B and CN118958922B authorized in 2024 respectively disclose a tower-type energy-saving pumping unit and a double-link reversing pumping unit and method. The motor reduction and mechanical reversing drive device of this type of pumping unit are located at the top of the tower. The invention patent CN108643866B authorized in 2020 discloses a mechanical automatic reversing double-well long-stroke pumping unit, which uses a conventional two-stage reduction to drive the beam to swing and drive the sucker rods at both ends to move up and down. The invention patent CN113638718B authorized in 2022 discloses a chain reversing pumping unit, and the invention patent CN1031354C authorized in 1996 discloses a chain-type long-stroke pumping unit. This type of pumping unit drives the sucker rod to move through the reversing drive of the circulating ascending and descending chain and the reversing balance box. The invention patent CN103867164B authorized in 2016 discloses a long-stroke pumping unit, in which the motor drives the large driving pulley to decelerate through a small pulley and a belt, and then drives the sucker rod to reciprocate over a long distance through multiple sets of fixed and movable pulley blocks and steel wire ropes. The invention patent CN100564794 authorized in 2009 discloses a lever-balanced crown-block long-stroke pumping unit, which uses a lower-mounted driving pendulum wheel to increase the stroke, a single crank connecting rod and a lever-type balance structure to achieve stroke increase. The invention patent with the publication number CN1061739C in 2001 discloses a motor-reversing long-stroke pumping unit that uses motor reversing instead of mechanical reversing. The invention patent with the publication number CN102704897B in 2014 discloses a gravity-balanced hydraulic long-stroke pumping unit. The invention patent with the publication number CN102352740B in 2014 discloses a compound-balanced long-stroke pumping unit, which reduces the weight of the counterweight through a compound balance structure.

[0005] The above existing technologies each have their own characteristics, but there are also the following deficiencies: 1. During the commutation process, the impact load is relatively large, the reliability is not good enough, and the structure is not compact enough. 2. For the pumping unit with the motor reduction and mechanical commutation drive device located at the top of the tower, the center height is high, the stability is poor, and the maintenance is difficult. 3. In the chain commutation process of the chain commutation pumping unit, the commutation load of the chain joint pin is large and it is easy to break, and the chain joints are easy to rust and wear. 4. The reduction ratio of the multiple sets of fixed and movable pulley blocks and steel wire rope transmission is small, and the steel wire rope is continuously subjected to large loads for a long time, and is easy to rust, wear and break due to multiple reverse winding. 5. The reliability of electrical commutation is not good enough. 6. The mechanical commutation impact load of the lever-balanced crown-block long-stroke pumping unit is large and the structure is relatively complex. 7. The counterweight generates a large bending moment on the support shaft, and the safety performance is not good. Summary of the Invention

[0006] In view of the above problems, the object of the present invention is to provide a double planetary gear drive pulley long - stroke pumping unit, which has the characteristics of large transmission ratio, high efficiency, strong bearing capacity, long stroke, high pump efficiency, good variable - load balance, compact structure, excellent sealing and lubrication performance, etc.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A double planetary gear drive pulley long - stroke pumping unit proposed by the present invention includes a frame, a double planetary gear drive group, a pulley group, and a sucker rod; the double planetary gear drive group is arranged at the lower left side of the frame; the pulley group is connected between the double planetary gear drive group and the top right side of the frame; the sucker rod is connected to the outer end of the pulley group.

[0009] Furthermore, the frame includes a bottom plate, columns, a rectangular cross - beam, inclined beams, a left vertical plate, and a right vertical plate; the columns are vertically and fixedly connected to the upper surface of the right side of the bottom plate; the rectangular cross - beam is fixedly connected to the top of the columns and is parallel to the bottom plate, and there are through - holes parallel to the short sides of the rectangle and a central slot perpendicular to the through - holes at the rear end of the rectangular cross - beam; the two ends of the inclined beams are respectively fixedly connected to the front end of the rectangular cross - beam and the bottom plate; the left vertical plate and the right vertical plate are successively and vertically fixedly connected to the left - hand side area of the upper surface of the bottom plate and are parallel to each other, and concentric through - holes perpendicular to the plate surfaces are respectively arranged at the upper ends of the left vertical plate and the right vertical plate.

[0010] Furthermore, the double planetary gear drive group includes a motor, a driving wheel, a central fixed wheel, three identical double planetary gears, a planetary gear frame box, a balance weight, an output shaft, and an output swing arm; the central fixed wheel, the driving wheel, and the three double planetary gears are all arranged inside the planetary gear frame box; the left - hand side shaft of the central fixed wheel is coaxially and rotatably connected to the inside of the left - hand side of the planetary gear frame box, and its left - hand end shaft extends to the outside of the left - hand side of the planetary gear frame box; the output shaft is coaxially and fixedly connected to the outside of the right - hand end face of the planetary gear frame box; the three double planetary gears are circumferentially evenly distributed inside the planetary gear frame box, and the two ends of the double planetary gears are respectively rotatably connected to the planetary gear frame box; the right - hand side gear of the central fixed wheel meshes with the left - hand side planetary gears of the three double planetary gears simultaneously; the motor is fixedly connected to the left - hand end of the central fixed wheel; the driving wheel is coaxially arranged in the middle of the planetary gear frame box, and one side shaft of the driving wheel is rotatably connected to the central fixed wheel, and the other side gear meshes with the right - hand side planetary gears of the three double planetary gears simultaneously; the left - hand end of the driving wheel is key - connected to the output shaft of the motor; the left - hand side shaft of the central fixed wheel is coaxially and fixedly connected to the concentric through - hole at the upper end of the left vertical plate; the output shaft is rotatably connected to the concentric through - hole at the upper end of the right vertical plate, and the right - hand end of the output shaft is fixedly connected to the left - hand side of the output swing arm; the balance weight is fixedly connected to one side of the outer circumference of the planetary gear frame box.

[0011] Furthermore, the distance from the center of gravity of the balance weight to the axis of the end hole of the output swing arm is set as the shortest distance.

[0012] Further, the pulley set includes a movable pulley, a fixed pulley, and a traction belt; the movable pulley is rotatably connected to the outer end of the output swing arm; the fixed pulley is rotatably connected to the central slot at the rear end of the rectangular cross beam; one end of the traction belt is connected to the front end of the rectangular cross beam, and the other end is sequentially wound around the movable pulley and the fixed pulley and then connected to the upper end of the sucker rod.

[0013] Further, the traction belt is composed of multiple thin steel wires covered with rubber.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The double planetary gear drive and the pulley set are in series drive, and the reversing process of the sucker rod is continuous and without impact. The required output arm length is reduced. With a 1.5m long output arm, the stroke of the sucker rod reaches 6m, the pump efficiency is high, and the energy consumption is reduced. Moreover, the base height of the double planetary gear drive is reduced, the stability is improved, the machine length is half of that of the beam pumping unit, and the structure is compact and the floor area is small.

[0016] 2. The double planetary gear drive has a large reduction ratio (up to 26:1), a short transmission chain, high efficiency, continuous single-direction rotation, stable load, long service life, good lubrication and sealing performance, avoiding the accidents of high-speed belt slipping, belt detachment, and belt aging and breakage of the beam pumping unit, and adapting to the working conditions of sand, water accumulation, ice, rain, snow, and sudden temperature changes in the oil field.

[0017] 3. The double planetary gear drive has a large anti-torsion strength; the large and small gears of the three planetary gear sets are simultaneously meshed with the central drive gear and the central fixed gear in a balanced and uniform load manner, realizing the uniform distribution and balanced and uniform load meshing of the gear meshing force, effectively improving the anti-torsion strength and the transmission torque capacity of the double planetary gear drive; the anti-torsion strength / transmission torque capacity of the gear drive is three times higher than that of the conventional two-stage reducer with the same volume and the same gear module.

[0018] 4. The double planetary gear drive uses a central fixed small gear to replace the fixed large-diameter internal gear of the existing planetary drive, increasing the reduction ratio of the double planetary gear drive and reducing the manufacturing cost.

[0019] 5. The planetary carrier box is connected to the balance weight and rotates between two support plates, reducing the torque difference between the motor and the double planetary gear drive during the lifting and lowering process of the sucker rod, and avoiding the additional bending moment generated by the cantilever rotating balance weight of the existing beam pumping unit on the output shaft. At the same time, the planetary carrier box carries and rotates the lubricating oil to continuously pour on each gear pair and rotating pair, effectively reducing the oil temperature in the box, improving the lubrication conditions, and extending the working life.

[0020] 6. The traction belt is a wire rope belt composed of multiple thin steel wires arranged side by side and wrapped with rubber, having the advantages of high tensile strength, wear resistance, corrosion resistance, and good flexibility. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the front view sectional structure of the present invention;

[0022] Figure 2 is Figure 1 the schematic side view structure diagram in

[0023] Among them, the reference numerals: 1 - frame; 1-1 - bottom plate; 1-2 - column; 1-3 - cross beam; 1-4 - inclined beam; 1-5 - left vertical plate; 1-6 - right vertical plate; 2 - motor; 3 - driving wheel; 4 - center fixed wheel; 5 - double planetary wheel; 6 - planetary wheel frame box body; 7 - balance weight; 8 - output shaft; 9 - output swing arm; 10 - movable pulley; 11 - fixed pulley; 12 - traction belt; 13 - sucker rod. Specific embodiments

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] It should be noted that in the description of the present invention, the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "one side", "the other side", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating that the device or element must have a specific orientation, be constructed and operated in a specific orientation.

[0026] Referring to the attached Figure 1-2 , a double planetary wheel drive pulley long - stroke pumping unit proposed by the present invention includes a frame 1, a double planetary wheel drive group, a pulley group, and a sucker rod 13; the double planetary wheel drive group is arranged at the lower left side of the frame 1; the pulley group is connected between the double planetary wheel drive group and the upper right side of the frame 1; the sucker rod 13 is connected to the outer end of the pulley group.

[0027] Among them, the frame 1 includes a bottom plate 1-1, columns 1-2, a rectangular cross beam 1-3, inclined beams 1-4, a left vertical plate 1-5, and a right vertical plate 1-6; the columns 1-2 are vertically and fixedly connected to the upper right surface of the bottom plate 1-1; the rectangular cross beam 1-3 is fixedly connected to the top of the columns 1-2 and is parallel to the bottom plate 1-1. There are through holes parallel to the short side of the rectangle and a central slot perpendicular to the through holes at the rear end of the rectangular cross beam 1-3; the two ends of the inclined beam 1-4 are respectively fixedly connected to the front end of the rectangular cross beam 1-3 and the bottom plate 1-1; the left vertical plate 1-5 and the right vertical plate 1-6 are sequentially and vertically fixedly connected to the left side area of the upper surface of the bottom plate 1-1 and are parallel to each other, and concentric through holes perpendicular to the plate surfaces are respectively arranged at the upper ends of the left vertical plate 1-5 and the right vertical plate 1-6.

[0028] The double planetary gear transmission set includes a motor 2, a driving wheel 3, a central fixed gear 4, three identical double planetary gears 5, a planetary gear carrier housing 6, a balance weight 7, an output shaft 8, and an output swing arm 9;

[0029] The central fixed gear 4, the driving wheel 3, and the three double planetary gears 5 are all arranged inside the planetary gear carrier housing 6; the left shaft of the central fixed gear 4 is coaxially and rotatably connected inside the left side of the planetary gear carrier housing 6, and its left end shaft extends to the outside of the left side of the planetary gear carrier housing 6; the output shaft 8 is coaxially fixedly connected to the outside of the right end face of the planetary gear carrier housing 6; the three double planetary gears 5 are circumferentially evenly distributed inside the planetary gear carrier housing 6, and both ends of the double planetary gears 5 are rotatably connected to the planetary gear carrier housing 6; the right gear of the central fixed gear 4 meshes with the left planetary gears of the three double planetary gears 5 at the same time; the motor 2 is fixedly connected to the left end of the central fixed gear 4; the driving wheel 3 is coaxially arranged in the middle of the planetary gear carrier housing 6, and one side shaft of the driving wheel 3 is rotatably connected to the central fixed gear 4, and the other side gear meshes with the right planetary gears of the three double planetary gears 5 at the same time; the left end of the driving wheel 3 is key-connected to the output shaft of the motor 2; the left shaft of the central fixed gear 4 is coaxially and fixedly connected to the concentric through hole at the upper end of the left vertical plate 1-1; the output shaft 8 is rotatably connected to the concentric through hole at the upper end of the right vertical plate 1-2, and the right end of the output shaft 8 is fixedly connected to the left side of the inner end of the output swing arm 9; the balance weight 7 is fixedly connected to one side of the outer circumference of the planetary gear carrier housing 6.

[0030] Specifically, the central fixed gear 4 is axially arranged as a coaxial cylinder, a large gear, and an axial through hole in sequence; the driving wheel 3 is axially arranged as a coaxial cylinder and a small gear in sequence, and an axial key hole is opened at the cylinder end; the double planetary gear 5 is axially arranged as a coaxial cylinder, a small gear, a large gear, and a cylinder in sequence, the module of its small gear is the same as the gear module of the central fixed gear 4, and the module of its large gear is the same as the gear module of the driving wheel 3; the planetary gear carrier housing 6 is axially arranged as a rotary shell formed by connecting a coaxial small cylinder and a large cylinder, an axial through hole at the end face of the small cylinder, an axial positioning hole at the end face of the large cylinder, and a plurality of axially threaded holes circumferentially evenly distributed, three axially through holes circumferentially evenly distributed on the same circumference of the small cylinder and the large cylinder, and a plurality of axially threaded holes circumferentially evenly distributed on the circumferential connection surface between the large cylinder and the small cylinder; the output shaft 8 is axially arranged as a coaxial frustum, a left disc, a cylinder, a right disc, and a right cylinder in sequence, and a plurality of axially through holes circumferentially evenly distributed are arranged at the positions of the left disc and the right disc corresponding to the threaded holes on the large cylinder end face of the planetary gear carrier housing 6; the output swing arm 9 is a rectangular plate, one end of which is provided with a through hole perpendicular to the rectangular plate, and the other end is provided with a through hole perpendicular to the rectangular plate and a plurality of axially through holes circumferentially evenly distributed corresponding to the axial through holes of the right disc of the output shaft 8; the balance weight 7 is an arc-shaped block, the inner arc radius of which is the same as the radius of the large cylinder of the star gear carrier housing 6, and its left end is provided with a radial boss towards the center and a plurality of circumferentially evenly distributed through holes perpendicular to the boss.

[0031] Among them, the gear of the central fixed gear 4, the gear of the driving wheel 3, and the three double planetary gears 5 are all arranged in the planetary gear carrier housing 6. The cylinder of the central fixed gear 4 is rotatably connected to the central through hole of the small cylinder end of the planetary gear carrier housing 6. The axial positioning hole at the center of the large cylinder end face of the planetary gear carrier housing 6 is coaxially positioned and connected to the round table of the output shaft 8. The circumferential threaded holes on the large cylinder end face of the planetary gear carrier housing 6 are connected to the circumferential axial through holes of the disk of the output shaft 8 with screws; the two ends of the three double planetary gears 5 are respectively rotatably connected to three through holes evenly distributed on the circumference of the planetary gear carrier housing 6; the gear of the central fixed gear 4 meshes with the small gears of the three double planetary gears 5 at the same time. The motor 2 is fixedly connected to the cylinder end of the central fixed gear 4. The output shaft of the motor 2 is key-connected to the key hole of the driving wheel 3. The cylinder of the driving wheel 3 is rotatably connected to the through hole of the central fixed gear 4. The gear of the driving wheel 3 meshes with the large gears of the three double planetary gears 5 at the same time; the cylinder of the central fixed gear 4 is coaxially and fixedly connected to the through hole at the upper end of the left vertical plate 1-5. The cylinder of the output shaft 8 is rotatably connected to the through hole at the upper end of the right vertical plate 1-6. The right cylinder of the output shaft 8 is connected to the large round through hole of the output swing arm 9. The circumferential through holes of the right disk of the output shaft 8 are fixedly connected to the circumferential through holes of the output swing arm 9 with screws; the multiple axial through holes of the arc-shaped convex platform of the balance weight 7 are fixedly connected to the multiple threaded holes on the radial connection surfaces of the large and small cylinders of the planetary gear carrier housing 6 with screws, and the distance from the center of gravity of the balance weight 7 to the axis of the end hole of the output swing arm 9 is made the shortest.

[0032] The pulley group includes a movable pulley 10, a fixed pulley 11, and a traction belt 12; the movable pulley 10 and the fixed pulley 11 have the same structure, and coaxial through holes are provided at their axles, and circumferential grooves are provided at their rims; the through hole of the movable pulley 10 is rotatably connected to the end through hole of the output swing arm 9 with a cantilever pin shaft; the fixed pulley 11 is arranged in the central slot at the rear end of the rectangular cross beam 1-3. The through hole of the fixed pulley 11 is rotatably connected to the through holes on both sides of the central slot of the rectangular cross beam 1-3 with a pin shaft; one end of the traction belt 12 is connected to the front end of the rectangular cross beam 1-3, and the other end is sequentially wound around the movable pulley 10 and the fixed pulley 11 and then connected to the upper end of the sucker rod 13.

[0033] The traction belt 12 is a rubber-coated tape arranged with multiple thin steel wires.

[0034] The motor 2 of the present invention drives the large gears of three double planetary gears 5 simultaneously through the driving wheel 3 of the double planetary gear transmission group to drive the small gears to rotate synchronously for the first-stage deceleration. The small gears of the three double planetary gears 5 are simultaneously meshed with the gears of the central fixed wheel 4, driving the planetary gear carrier housing 6 to rotate for the second-stage deceleration relative to the machine base 1. The planetary gear carrier housing 6 drives the output rotating arm 9 to rotate synchronously through the output shaft 8, driving the movable pulley 10 to rotate relative to the machine base 1. Finally, the movable pulley 10, fixed pulley 11 and traction belt 12 of the pulley group are used to traction the sucker rod 13 to reciprocate up and down. On the premise of meeting the working speeds of the motor 2 and the sucker rod 13, the present invention adopts a double planetary gear transmission with a large reduction ratio and a pulley group with stroke multiplication, effectively increasing the reciprocating stroke of the sucker rod 13. At the same time, the balance weight 7 connected to the planetary gear carrier housing 6 effectively reduces the torque fluctuation amplitude of the unidirectional continuously rotating motor 2 and the double planetary gear transmission group caused by the load difference of the reciprocating motion of the sucker rod 13, so as to achieve the dual goals of improving the pump efficiency and saving energy.

[0035] Matters not detailed in the present invention are well-known technologies.

[0036] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A double planetary gear drive pulley long stroke pumping unit, characterized in that: It includes a frame, a double planetary gear transmission group, a pulley group, and a sucker rod; the double planetary gear transmission group is arranged at the lower left of the frame; the pulley group is connected between the double planetary gear transmission group and the top right of the frame; the sucker rod is connected to the outer end of the pulley group.

2. The double planetary gear drive pulley long stroke pumping unit according to claim 1, wherein: The frame includes a bottom plate, columns, a rectangular cross beam, inclined beams, a left vertical plate, and a right vertical plate; the columns are vertically and fixedly connected to the upper right surface of the bottom plate; the rectangular cross beam is fixedly connected to the top of the columns and is parallel to the bottom plate, and a through hole parallel to the short side of the rectangle and a central slot perpendicular to the through hole are provided at the rear end of the rectangular cross beam; the two ends of the inclined beams are respectively fixedly connected to the front end of the rectangular cross beam and the bottom plate; the left vertical plate and the right vertical plate are successively and vertically fixedly connected to the left side area of the upper surface of the bottom plate and are parallel to each other, and concentric through holes perpendicular to the plate surfaces are provided at the upper ends of the left vertical plate and the right vertical plate.

3. A double planetary gear drive pulley long stroke pumping unit according to claim 2, characterized in that: The double planetary gear transmission group includes a motor, a driving wheel, a central fixed wheel, three identical double planetary gears, a planetary gear frame box, a balance weight, an output shaft, and an output rotating arm; the central fixed wheel, the driving wheel, and the three double planetary gears are all arranged inside the planetary gear frame box; the left shaft of the central fixed wheel is coaxially rotatably connected to the inside left of the planetary gear frame box, and its left end shaft extends to the outside left of the planetary gear frame box; the output shaft is coaxially fixedly connected to the outside of the right end face of the planetary gear frame box; the three double planetary gears are circumferentially evenly distributed inside the planetary gear frame box, and both ends of the double planetary gears are respectively rotatably connected to the planetary gear frame box; the right gear of the central fixed wheel meshes with the left planetary gears of the three double planetary gears at the same time; the motor is fixedly connected to the left end of the central fixed wheel; the driving wheel is coaxially arranged in the middle of the planetary gear frame box, and one side shaft of the driving wheel is rotatably connected to the central fixed wheel, and the other side gear meshes with the right planetary gears of the three double planetary gears at the same time; the left end of the driving wheel is key-connected to the output shaft of the motor; the left shaft of the central fixed wheel is coaxially fixedly connected to the concentric through hole at the upper end of the left vertical plate; the output shaft is rotatably connected to the concentric through hole at the upper end of the right vertical plate, and the right end of the output shaft is fixedly connected to the left side of the output rotating arm; the balance weight is fixedly connected to one side of the outer circumference of the planetary gear frame box.

4. A double planetary gear drive pulley long stroke pumping unit according to claim 3, characterized in that: The distance from the center of gravity of the balance weight to the axis of the end hole of the output rotating arm is set as the shortest distance.

5. The double planetary gear drive pulley long stroke pumping unit according to claim 3, characterized in that: The pulley group includes a movable pulley, a fixed pulley, and a traction belt; the movable pulley is rotatably connected to the outer end of the output rotating arm; the fixed pulley is rotatably connected to the central slot at the rear end of the rectangular cross beam; one end of the traction belt is connected to the front end of the rectangular cross beam, and the other end is successively wound around the movable pulley and the fixed pulley and then connected to the upper end of the sucker rod.

6. The double planetary gear drive pulley long stroke pumping unit according to claim 5, characterized in that: The traction belt is composed of multiple thin steel wires coated with rubber.

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