A lower-mounted electric cylinder connecting mechanism with a convenient oil seal

Abstract

The utility model discloses a lower -positioned electric cylinder connecting mechanism convenient to replace oil seal, the utility model discloses an electric cylinder shell and the electric cylinder swing frame below of bearing seat connection upper, the bottom fixed support cylinder of bearing seat, set up the diaphragm coupling in the support cylinder inside, utilize the diaphragm coupling and be connected in the ball screw of electric cylinder shell and the output shaft of servo motor in the electric cylinder swing frame, this kind of structure form does not exist the risk of high altitude operation, and only need to dismantle diaphragm coupling can carry out maintenance or replacement to the skeleton oil seal of main bearing bottom, effectively solved the skeleton oil seal periodical dismounting replacement problem, improved system convenient maintainability.

Description

Technical Field

[0001] This utility model relates to the field of petroleum extraction technology, and in particular to a bottom-mounted electric cylinder connection mechanism that facilitates the replacement of oil seals. Background Technology

[0002] In order to overcome the shortcomings of existing oilfield pumping units, which are bulky and energy-consuming, and to widely apply new pumping units, it is necessary to redesign existing pumping units to achieve more efficient, energy-saving and safer oil pumping operations.

[0003] Electric cylinder pumping units are a widely promoted energy-saving, environmentally friendly, and efficient oil extraction method, and also a long-term focus of the applicant's petroleum equipment manufacturing efforts. The electric cylinder pumping unit uses a servo motor as its output power, which, through the application of a ball screw, directly forms the electric cylinder drive system to drive the walking beam up and down. Assisted by an adjustable counterweight, the up-and-down swing of the walking beam drives the pumping head up and down, thus achieving stable and effective oil extraction. The electric cylinder drive system, which provides the power, is a key component in this process.

[0004] In recent years, the applicant has made significant efforts in research and development and has applied for a series of patents related to oil pumping units, including 201810655255.X, 202021887556.4, and 202110293327.2. These patents mainly focus on the design and use of electric cylinder-driven oil pumping units. Currently, some of these devices are already undergoing experimental and production practice in oil fields. These advancements significantly surpass those of domestic and international competitors, paving the way for large-scale application in oil fields and enabling energy-saving and high-efficiency oil pumping.

[0005] Currently, the servo motor is located at the top of the pumping unit's electric cylinder drive system. The high installation position of the servo motor makes maintenance or repair difficult. In case of a malfunction, in addition to stopping the machine, the electric cylinder drive system of the pumping unit must be disassembled to open the servo motor. In order to facilitate motor maintenance and avoid working at height, it is considered to design the servo motor at the bottom of the pumping unit's drive electric cylinder. However, this design requires solving the problem of potential oil leakage in the oil sump inside the electric cylinder and the problem of regularly disassembling and replacing the oil seal. Summary of the Invention

[0006] In view of this, the present invention provides a lower-mounted electric cylinder connection mechanism that facilitates the replacement of oil seals, in order to solve the problems existing in the background art.

[0007] A bottom-mounted electric cylinder connection mechanism for easy oil seal replacement includes a bearing housing embedded in the top of the electric cylinder swing frame and fixedly connected to the bottom of the electric cylinder housing, a support cylinder disposed inside the electric cylinder swing frame and fixed to the bottom of the bearing housing, and a diaphragm coupling disposed inside the support cylinder.

[0008] The bearing housing is equipped with a main bearing. The lower end of the ball screw, which is vertically installed inside the electric cylinder housing, passes downward through the main bearing and connects to one end of the diaphragm coupling.

[0009] The electric cylinder swing frame is equipped with a servo motor located below the support cylinder. The output shaft of the servo motor passes upward through the support cylinder and is connected to the other end of the diaphragm coupling.

[0010] Preferably, the bottom of the support cylinder is fixed with a motor support by fasteners, and the servo motor is fixed on the motor support.

[0011] Preferably, a permanent magnet brake is also provided on the output shaft of the servo motor, and the top of the permanent magnet brake is fixed to the bottom of the support cylinder.

[0012] Preferably, the support cylinder is a cylindrical structure with an open top. The support cylinder is fixed to the bearing seat by fasteners, and a through hole is opened in the center of the bottom of the support cylinder to allow the output shaft of the servo motor to pass through.

[0013] Preferably, the diaphragm coupling is a split diaphragm coupling.

[0014] Preferably, the bottom of the bearing housing is further provided with an oil seal seat, an oil slinger, and an oil receiving tray. The oil seal seat is fixed to the bottom of the bearing housing and is equipped with a PTFE oil retainer ring, a skeleton oil seal, and a magnetic suction device. The PTFE oil retainer ring and the skeleton oil seal are both mounted on the ball screw, with the opening of the skeleton oil seal facing the same direction. The oil slinger is mounted on the ball screw and is used to sling the oil leaking from the skeleton oil seal into the oil receiving tray. The oil receiving tray is fixed to the oil seal seat.

[0015] The beneficial effects of this utility model are:

[0016] 1. This application utilizes a bearing housing to connect the upper electric cylinder housing and the lower electric cylinder swing frame. A support cylinder is fixed at the bottom of the bearing housing, and a diaphragm coupling is installed inside the support cylinder. The diaphragm coupling connects the ball screw located inside the electric cylinder housing and the output shaft of the servo motor located inside the electric cylinder swing frame. This structure eliminates the risk of working at height, and the skeleton oil seal at the bottom of the main bearing can be maintained or replaced simply by removing the diaphragm coupling. This effectively solves the problem of periodically disassembling and replacing the skeleton oil seal, improving the system's maintainability.

[0017] 2. The bearing housing base of this application is also provided with an oil seal seat, an oil slinger, and an oil receiving tray. A PTFE oil retainer ring and a skeleton oil seal are provided in the gap between the oil seal seat and the ball screw. The PTFE oil retainer ring and the skeleton oil seal cooperate to prevent the lubricating oil in the oil sump from leaking out, so as to ensure the cleanliness of the inside of the support cylinder and the electric cylinder swing frame. In case of oil leakage, the oil slinger can throw the leaked lubricating oil into the oil receiving tray as the ball screw rotates. The oil receiving tray can collect the leaked lubricating oil. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the lower-mounted electric cylinder connection mechanism of this utility model.

[0020] Figure 2 This is a schematic diagram of a bottom-mounted electric cylinder drive system.

[0021] Figure 3 This is a schematic diagram of the connection between the ball screw and the inner and outer tubes in a bottom-mounted electric cylinder drive system.

[0022] Figure 4 This is an enlarged view of the structure of the oil seal seat, oil slinger, and oil receiving tray installed at the bottom of the bearing housing.

[0023] The meanings of the labels in the diagram are as follows:

[0024] 1—Servo motor, 2—Electric cylinder swing frame, 3—Bearing seat, 4—Diaphragm coupling, 5—Ball screw, 6—Ball screw nut, 7—Main bearing, 8—Outer tube of electric cylinder, 9—Inner tube of electric cylinder, 10—Inner tube swing seat, 11—Radial adjusting bearing, 12—Inner and outer tube straightening and anti-leakage device, 13—Support cylinder, 14—Oil seal seat, 15—Oil slinger, 16—Oil receiving tray, 17—Lubricating oil pool, 18—Permanent magnet brake, 19—Inner and outer tube straightening guide bar, 20—Screw locking nut, 21—Upper guide sleeve of inner and outer tube, 22—Fixing nut, 23—Lower guide sleeve of inner and outer tube, 24—PTFE oil retainer ring, 25—Skeleton oil seal, 26—Magnet, 27—Motor support. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the present utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present utility model.

[0026] To better understand the technical solution of this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings.

[0027] This utility model provides a bottom-mounted electric cylinder connection mechanism for convenient oil seal replacement. This connection mechanism is located between the electric cylinder housing and the electric cylinder swing frame of the pumping unit drive electric cylinder, and is used to connect the servo motor 1 and the ball screw 5. The pumping unit drive electric cylinder is a bottom-mounted electric cylinder drive system, meaning the servo motor is located at the bottom of the electric cylinder drive system.

[0028] Specifically, the lower-mounted electric cylinder connection mechanism of this application includes a bearing seat 3, a support cylinder 13 disposed inside the electric cylinder swing frame 2 and fixed to the bottom of the bearing seat 3, and a diaphragm coupling 4 disposed inside the support cylinder 13.

[0029] The bearing seat 3 is embedded in the top of the electric cylinder swing frame 2 and fixedly connected to the bottom of the electric cylinder housing. The electric cylinder swing frame 2 is located below, and the electric cylinder housing is located above. The main bearing 7 is installed on the bearing seat 3. The lower end of the ball screw 5, which is vertically installed in the electric cylinder housing, passes downward through the main bearing 7 and is connected to one end of the diaphragm coupling 4.

[0030] The electric cylinder swing frame 2 is equipped with a servo motor 1 inside, and the servo motor 1 is located below the support cylinder 13. The output axis of the servo motor 1 passes through the support cylinder 13 upward and is connected to the other end of the diaphragm coupling 4.

[0031] In this embodiment, the support cylinder 13 is a cylindrical structure with an open top. The support cylinder 13 is fixed to the bearing seat 3 by fasteners. A through hole is opened in the center of the bottom of the support cylinder 13 to allow the output shaft of the servo motor 1 to pass through.

[0032] Specifically, when installing the servo motor, a motor support 27 can be fixed to the bottom of the support cylinder 13 with fasteners, and the servo motor can be fixed on the motor support 27. The output end of the servo motor 1 passes through the through hole in the center of the support cylinder 13 and is connected to the lower end of the diaphragm coupling 4.

[0033] The servo motor 1 can be a servo motor with a brake, that is, a permanent magnet brake 18 is provided on the output shaft of the servo motor 1. The servo motor with a brake has a stop braking function. In order to increase the braking effect and achieve double braking insurance, a permanent magnet brake 18 is specially set to enhance the braking effect. The braking component of the permanent magnet brake 18 is clamped on the output shaft of the servo motor 1.

[0034] During installation, the permanent magnet brake 18 is clamped onto the output shaft of the servo motor 1, and the top of the permanent magnet brake 18 is fixed to the support cylinder 13. The top of the support cylinder 13 is fixed to the bottom of the bearing seat 3. A coupling 4 is provided inside the support cylinder 13. One end of the coupling 4 is connected to the output shaft of the servo motor 1, and the other end is connected to the bottom of the ball screw 5.

[0035] In this embodiment, the coupling 4 is a split diaphragm coupling, which detachably connects the output shaft of the servo motor 1 and the end of the ball screw 5. The purpose of setting up the split diaphragm coupling is to facilitate maintenance and repair of the components at the bottom of the main bearing 7.

[0036] In a preferred embodiment, the bottom of the bearing housing is further provided with an oil seal seat, an oil slinger, and an oil receiving tray. The oil seal seat is fixed to the bottom of the bearing housing and is equipped with a PTFE oil retainer ring 24, a skeleton oil seal 25, and a magnet 26. The PTFE oil retainer ring 24 and the skeleton oil seal 25 are both sleeved on the ball screw 5. The combination of the PTFE oil retainer ring and the skeleton oil seal prevents lubricating oil leakage. The magnet 26 is embedded in the oil seal seat 14 and is used to adsorb iron-containing impurities in the lubricating oil, thereby achieving cleaning and impurity removal. Specifically, the PTFE oil retainer ring 24 and the skeleton oil seal 25 are both sandwiched in the gap between the oil seal seat 14 and the ball screw 5, with the skeleton oil seal 25 located below the PTFE oil retainer ring 24. When installing the skeleton oil seal, its opening faces upward to prevent lubricating oil from leaking downward. The oil slinger is sleeved on the ball screw and is used to throw the leaking oil from the skeleton oil seal into the oil receiving tray, which is fixed to the oil seal seat.

[0037] In this embodiment, the PTFE oil retainer ring 24 is a boss-shaped ring structure made of PTFE material. The PTFE oil retainer ring 24 is mainly used to isolate the impact of the lubricating oil driven by the servo motor 1 during forward and reverse rotation on the oil seal lip of the skeleton oil seal 25, so as to ensure the sealing stability of the skeleton oil seal 25. At the same time, it can also reduce the pressure of the lubricating oil on the oil seal lip of the skeleton oil seal 25. The assembly gap between the PTFE oil retainer ring and the ball screw does not exceed 0.01mm. The magnet is a flat cylinder and is embedded in the upper surface of the oil seal seat.

[0038] The oil seal seat, oil slinger, and oil receiving plate are all located inside the support cylinder, which keeps the exterior clean.

[0039] To facilitate understanding of the structure of this application, the structure of the aforementioned lower-mounted electric cylinder drive system is described below.

[0040] The lower-mounted electric cylinder drive system includes an outer cylinder tube 8, an inner cylinder tube 9, a ball screw 5, a servo motor 1, and an electric cylinder swing frame 2. The outer cylinder tube 8 and the inner cylinder tube 9 form the outer casing of the electric cylinder, the ball screw 5 is installed inside the inner cylinder tube 9, and the servo motor 1 is installed inside the electric cylinder swing frame 2.

[0041] The bottom of the electric cylinder swing frame 2 is connected to the electric cylinder base of the pumping unit, typically using a swingable connection method. A bearing seat 3 is located at the top of the electric cylinder swing frame 2, which is embedded in the inner wall of the frame to ensure a secure fixation and prevent wobbling, primarily to withstand greater weight and vibration. The servo motor 1, which provides output power, is typically a braked servo motor and drives the electric cylinder according to program instructions.

[0042] The servo motor 1 is fixed to the bearing housing 3 via a support cylinder 13. Specifically, one end of the servo motor 1 is fixed to one end of the support cylinder 13, and the other end of the support cylinder 13 is fixed to the bearing housing 3, ensuring that the centers of the servo motor 1, the support cylinder 13, and the bearing housing 3 are on the same axis. It can be seen that the servo motor 1 is integrally arranged at the bottom of the electric cylinder drive system, hence the name "bottom-mounted electric cylinder drive system." This ensures that the servo motor 1 is always at the bottom of the electric cylinder drive system, facilitating daily maintenance and allowing for timely inspection and repair in case of malfunction. Therefore, compared to existing technologies where the motor is located at the top, this system offers greater safety and maintenance convenience.

[0043] The output shaft of the aforementioned servo motor 1 is connected upwards to the coupling 4 via the support cylinder 13. The lower end of the ball screw 5, which extends downwards from the main bearing 7, is fixed by the screw locking nut 20 and is also connected to the coupling 4. That is, both the ball screw 5 and the output shaft of the servo motor 1 are connected to the coupling 4 to transmit rotational motion from the motor to the ball screw.

[0044] The ball screw nut 6 on the ball screw 5 is fixedly connected to the bottom of the inner tube 9 of the electric cylinder. The top of the ball screw 5 is slidably mounted in the inner tube 9 of the electric cylinder via a radial adjusting bearing 11. That is, the top of the ball screw 5 slides up and down in the inner tube 9 of the electric cylinder along with the radial adjusting bearing 11. A guide strip, typically made of PTFE, is embedded on the edge sidewall of the radial adjusting bearing, and slides in contact with the inner wall of the inner tube 9. The ball screw nut 6 moves forward or backward on the ball screw 5, causing the inner tube 9 of the electric cylinder to move forward or backward. The top of the inner tube 9 of the electric cylinder is connected to the walking beam of the pumping unit via an inner tube swing seat 10.

[0045] like Figure 2As shown, the bottom of the outer tube 8 of the electric cylinder is fixed to the bearing seat 3 at the top of the electric cylinder swing frame 2 by screws. The inner tube 9 of the electric cylinder is threadedly connected to the roller screw nut 6 and moves linearly up and down within the outer tube 8 with the roller screw nut 6, thereby driving the walking beam of the pumping unit to swing up and down around the central fulcrum. An electric cylinder piston mechanism is provided between the outer tube 8 and the inner tube 9, specifically including upper guide sleeves 21, a fixing nut 22, and lower guide sleeves 23. The inner tube 9 is fixed to the roller screw nut 6 by the fixing nut 22 through the upper guide sleeves 21 and the lower guide sleeves 23. The upper guide sleeves 21 are located above the fixing nut 22, while the lower guide sleeves 23 are located below the fixing nut 22. The upper guide sleeves 21 and the lower guide sleeves 23 constitute the electric cylinder piston mechanism, allowing the inner tube 9 to move piston-like within the outer tube 8.

[0046] At the bottom of the outer tube 8 and the inner tube 9 of the electric cylinder, there is a lubricating oil pool 17 surrounding the ball screw 5. The bottom of the lubricating oil pool 17 is the main bearing 7 and the bearing seat 3, and the outer tube 8 of the electric cylinder is around it. The top of the lubricating oil pool 17 is the ball screw nut 6 and the lower guide sleeve 23 of the inner and outer tubes of the electric cylinder piston mechanism.

[0047] The oil seal seat 14, oil slinger 15 and oil receiving plate 16 provided at the bottom of the bearing housing 3 can prevent lubricating oil leakage, recycle and dispose of unavoidable leaked lubricating oil, and ensure that the inside of the support cylinder 13 remains clean and free of oil leakage from the outside of the electric cylinder swing frame 2.

[0048] The area formed between the oil seal seat 14 and the bearing seat 3 is also a lubricating oil pool 17 filled with lubricating oil, which surrounds the lower end of the ball screw 5, the main bearing 7 and the screw locking nut 20.

[0049] The upper part of the outer tube 8 and the inner tube 9 of the electric cylinder are connected by the inner and outer tube straightening guide strips 19 to straighten the inner tube 9 inside the outer tube 8, ensuring smooth and efficient up-and-down movement of the inner tube 9 and preventing the lubricating oil from being carried out of the outer tube 8 when the inner tube 9 moves up and down.

[0050] The top of the outer tube 9 of the electric cylinder is fixed with a flange by screws. The inner tube 9 of the electric cylinder passes through the through hole in the center of the flange. An annular groove for installing a skeleton oil seal is provided on the flange. The inner wall of the skeleton oil seal is in close contact with the outer wall of the inner tube 9 of the electric cylinder to prevent the inner tube 9 of the electric cylinder from carrying out lubricating oil when it rises. The opening of the skeleton oil seal faces downward to prevent lubricating oil from leaking out from bottom to top. Several grooves are provided on the flange. Inner and outer tube straightening guide strips 19 are provided in the grooves. The inner and outer tube straightening guide strips 19 are usually designed with multiple ribbons to straighten the inner tube 9 of the electric cylinder in the outer tube 8 of the electric cylinder, thereby ensuring that the inner tube 9 of the electric cylinder moves up and down smoothly and efficiently.

[0051] This bottom-mounted electric cylinder drive system adopts a servo motor design at the bottom. The servo motor at the bottom provides upward power, driving the ball screw to rotate. The ball screw nut drives the inner tube of the electric cylinder to move up and down, and then the swing beam moves up and down through the swing seat of the inner tube. By placing the servo motor in the swing frame of the electric cylinder at the bottom, closer to the pumping unit base on the ground, it is possible to stop and repair in time if a problem occurs, thus avoiding the high-altitude operation of the original technology and greatly improving safety and maintenance convenience.

[0052] It should be understood that the described embodiments are merely some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

Claims

1. A bottom-mounted electric cylinder connection mechanism for easy oil seal replacement, characterized in that, It includes a bearing housing embedded in the top of the electric cylinder swing frame and fixedly connected to the bottom of the electric cylinder housing, a support cylinder disposed inside the electric cylinder swing frame and fixed to the bottom of the bearing housing, and a diaphragm coupling disposed inside the support cylinder. The bearing housing is equipped with a main bearing. The lower end of the ball screw, which is vertically installed inside the electric cylinder housing, passes downward through the main bearing and connects to one end of the diaphragm coupling. The electric cylinder swing frame is equipped with a servo motor located below the support cylinder. The output shaft of the servo motor passes upward through the support cylinder and is connected to the other end of the diaphragm coupling.

2. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 1, characterized in that, The bottom of the support cylinder is fixed with a motor bracket by fasteners, and the servo motor is fixed on the motor bracket.

3. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 2, characterized in that, A permanent magnet brake is also provided on the output shaft of the servo motor, and the top of the permanent magnet brake is fixed to the bottom of the support cylinder.

4. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 1, 2, or 3, characterized in that, The support cylinder is a cylindrical structure with an open top. The support cylinder is fixed to the bearing seat by fasteners. A through hole is opened in the center of the bottom of the support cylinder to allow the output shaft of the servo motor to pass through.

5. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 1, characterized in that, The diaphragm coupling is a split-type diaphragm coupling.

6. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 1, characterized in that, The bottom of the bearing housing is also provided with an oil seal seat, an oil slinger, and an oil receiving tray. The oil seal seat is fixed to the bottom of the bearing housing and is equipped with a PTFE oil retainer ring and a skeleton oil seal. Both the PTFE oil retainer ring and the skeleton oil seal are mounted on the ball screw, with the opening of the skeleton oil seal facing the same direction. The oil slinger is mounted on the ball screw and is used to sling the oil leaking from the skeleton oil seal into the oil receiving tray. The oil receiving tray is fixed to the oil seal seat.

7. The lower-mounted electric cylinder connection mechanism for convenient oil seal replacement according to claim 6, characterized in that, The oil seal seat is also equipped with a magnet for adsorbing impurities in the lubricating oil.

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